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1.
J Clin Lipidol ; 2024 Mar 29.
Article in English | MEDLINE | ID: mdl-38825415

ABSTRACT

Patients attending vascular or diabetic foot clinics commonly have atherosclerotic disease, are at increased risk of cardiovascular disease (CVD), merit high-intensity lipid-modifying therapy to maintain secondary prevention targets and are often sub optimally treated in primary care. We set out to assess the impact of a pharmacist led lipid optimisation clinic in these patients in an area with high levels of social deprivation. METHODS: We performed a clinical cohort study to assess the effectiveness of a pharmacist led clinic to optimise lipid lowering therapy by optimising of statin therapy and commencing additional lipid lowering therapy if applicable with monitoring of blood lipid profiles. RESULTS: Of the 216 patients (166 (77%) on statins) triaged by the pharmacist, 175 (81%) had non-HDL cholesterol levels above the target value of 97 mg/dL (2.5 mmol/L) with a mean non-HDL cholesterol level of 135.73 mg/dL (3.51 mmol/L). Pre optimisation by the prescribing clinical pharmacist 41/216 (19%) patients were at target with a mean non-HDL cholesterol of 135.5 mg/dL improving to 92/137 (67%) patients achieving the target non-HDL cholesterol level with a mean post optimisation non-HDL cholesterol of 94.35 mg/dL (2.44 mmol/L), odds ratio for being at target 8.67 [95% CI 5.30-14.20]. The calculated LDL cholesterol levels (Friedewald) demonstrated a mean reduction of 35.19 [95% CI 29.23-41.38] mg/dL (0.91 [95% CI 0.76-1.07] mmol/l). Proportion on high intensity statin increased from 65 out of 166 (39%) to 129 of 170 (76%) at follow up O.R. 4.89 [3.06-7.82], equivalent to an NNT = 3. CONCLUSIONS: A pharmacist led service in undertreated and clinically challenging vascular and diabetic foot patients in an area of high social deprivation produced significant improvements in utilization of high intensity statin and other lipid lowering therapies and attainment of lipid goals.

2.
Physiol Meas ; 2024 Jun 05.
Article in English | MEDLINE | ID: mdl-38838703

ABSTRACT

Vascular ageing is the deterioration of arterial structure and function which occurs naturally with age, and which can be accelerated with disease. Measurements of vascular ageing are emerging as markers of cardiovascular risk, with potential applications in disease diagnosis and prognosis, and for guiding treatments. However, vascular ageing is not yet routinely assessed in clinical practice. A key step towards this is the development of technologies to assess vascular ageing. In this Roadmap, experts discuss several aspects of this process, including: measurement technologies; the development pipeline; clinical applications; and future research directions. The Roadmap summarises the state of the art, outlines the major challenges to overcome, and identifies potential future research directions to address these challenges.

3.
Br J Surg ; 110(12): 1785-1792, 2023 11 09.
Article in English | MEDLINE | ID: mdl-37748866

ABSTRACT

METHODS: This was an open, multicentre, randomized controlled trial. Patients with intermittent claudication attending vascular surgery outpatient clinics were randomized (1:1) to receive either neuromuscular electrical stimulation (NMES) or not in addition to local standard care available at study centres (best medical therapy alone or plus supervised exercise therapy (SET)). The objective of this trial was to investigate the clinical efficacy of an NMES device in addition to local standard care in improving walking distances in patients with claudication. The primary outcome was change in absolute walking distance, measured by a standardized treadmill test at 3 months. Secondary outcomes included intermittent claudication (IC) distance, adherence, quality of life, and haemodynamic changes. RESULTS: Of 200 participants randomized, 160 were included in the primary analysis (intention to treat, Tobit regression model). The square root of absolute walking distance was analysed (due to a right-skewed distribution) and, although adjunctive NMES improved it at 3 months, no statistically significant effect was observed. SET as local standard care seemed to improve distance compared to best medical therapy at 3 months (3.29 units; 95 per cent c.i., 1.77 to 4.82; P < 0.001). Adjunctive NMES improved distance in mild claudication (2.88 units; 95 per cent c.i., 0.51 to 5.25; P = 0.02) compared to local standard care at 3 months. No serious adverse events relating to the device were reported. CONCLUSION: Supervised exercise therapy is effective and NMES may provide further benefit in mild IC.This trial was supported by a grant from the Efficacy and Mechanism Evaluation Program, a Medical Research Council and National Institute for Health and Care Research partnership. Trial registration: ISRCTN18242823.


Patients with intermittent claudication experience pain in their legs during walking or exercise which ends with rest. This severely impairs physical activity and quality of life. Treatment for such patients typically involves best medical therapy, which includes exercise advice. This study aimed to determine whether a neuromuscular electrical stimulation device improved the walking distance of patients with intermittent claudication compared to local standard care available (which may include supervised exercise therapy) in a trial. Supervised exercise improved walking distances but there was no difference in those that received a device in this patient group.


Subject(s)
Intermittent Claudication , Quality of Life , Humans , Intermittent Claudication/therapy , Walking , Exercise Therapy , Treatment Outcome , Electric Stimulation
4.
Physiol Meas ; 44(11)2023 Nov 29.
Article in English | MEDLINE | ID: mdl-37494945

ABSTRACT

Photoplethysmography is a key sensing technology which is used in wearable devices such as smartwatches and fitness trackers. Currently, photoplethysmography sensors are used to monitor physiological parameters including heart rate and heart rhythm, and to track activities like sleep and exercise. Yet, wearable photoplethysmography has potential to provide much more information on health and wellbeing, which could inform clinical decision making. This Roadmap outlines directions for research and development to realise the full potential of wearable photoplethysmography. Experts discuss key topics within the areas of sensor design, signal processing, clinical applications, and research directions. Their perspectives provide valuable guidance to researchers developing wearable photoplethysmography technology.


Subject(s)
Photoplethysmography , Wearable Electronic Devices , Fitness Trackers , Signal Processing, Computer-Assisted , Heart Rate/physiology
5.
J Plast Reconstr Aesthet Surg ; 81: 138-148, 2023 06.
Article in English | MEDLINE | ID: mdl-37141788

ABSTRACT

Microsurgical breast reconstruction accounts for 22% of breast reconstructions in the UK. Despite thromboprophylaxis, venous thromboembolism (VTE) occurs in up to 4% of cases. Using a Delphi process, this study established a UK consensus on VTE prophylaxis strategy, for patients undergoing autologous breast reconstruction using free-tissue transfer. It captured geographically divergent views, producing a guide that reflected the peer opinion and current evidence base. METHODS: Consensus was ascertained using a structured Delphi process. A specialist from each of the UK's 12 regions was invited to the expert panel. Commitment to three to four rounds of questions was sought at enrollment. Surveys were distributed electronically. An initial qualitative free-text survey was distributed to identify likely lines of consensus and dissensus. Each panelist was provided with full-text versions of key papers on the topic. Initial free-text responses were analyzed to develop a set of structured quantitative statements, which were refined via a second survey as a consensus was approached. RESULTS: The panel comprised 18 specialists: plastic surgeons and thrombosis experts from across the UK. Each specialist completed three rounds of surveys. Together, these plastic surgeons reported having performed more than 570 microsurgical breast reconstructions in the UK in 2019. A consensus was reached on 27 statements, detailing the assessment and delivery of VTE prophylaxis. CONCLUSION: To our knowledge, this is the first study to collate current practice, expert opinion from across the UK, and a literature review. The output was a practical guide for VTE prophylaxis for microsurgical breast reconstruction in any UK microsurgical breast reconstruction unit.


Subject(s)
Mammaplasty , Venous Thromboembolism , Humans , Anticoagulants/therapeutic use , Venous Thromboembolism/prevention & control , Surveys and Questionnaires , United Kingdom
6.
Angiology ; 74(9): 859-867, 2023 10.
Article in English | MEDLINE | ID: mdl-35980897

ABSTRACT

Peripheral arterial disease (PAD) is associated with cerebral and coronary artery disease. Symptomatic PAD affects about 5% of people over 55 years; many more have asymptomatic PAD. Early detection enables modification of arterial disease risk factors. Diagnostically, assessment of symptoms or signs can be unreliable; ankle brachial pressure index (ABPI) testing is time-consuming and few healthcare professionals are properly trained. This study assessed the diagnostic accuracy of multi-site photoplethysmography (MPPG), an alternative non-invasive test for PAD, in primary care. PAD patients identified from general practice registers were age- and sex-matched with controls. Participants were assessed using MPPG, ABPI and duplex ultrasound (DUS). Outcome measures were sensitivity and specificity of MPPG and ABPI (relative to DUS) and concordance. MPPG test results were available in 249 of 298 eligible participants from 16 practices between May 2015 and November 2016. DUS detected PAD in 101/249 (40.6%). MPPG sensitivity was 79.8% (95% confidence interval [CI] 69.9-87.6%), with specificity 71.9% (95% CI 63.7-79.2%). ABPI sensitivity was 80.2% (95% CI 70.8-87.6%), with specificity 88.6% (95% CI 82-93.5%). With comparable sensitivity to ABPI, MPPG is quick, automated and simpler to do than ABPI; it offers the potential for rapid and accessible PAD assessments in primary care.


Subject(s)
Peripheral Arterial Disease , Photoplethysmography , Humans , Prospective Studies , Peripheral Arterial Disease/diagnosis , Ankle Brachial Index , Primary Health Care
7.
Eur J Vasc Endovasc Surg ; 64(2-3): 210-216, 2022.
Article in English | MEDLINE | ID: mdl-35472448

ABSTRACT

OBJECTIVE: Duplex ultrasound (DUS), a non-invasive means of arterial mapping, allows for the reliable diagnosis of peripheral arterial disease (PAD). One of the authors (C.P.O.), developed a standardised DUS based scoring system, devised for rapid detection and reporting of PAD. The purpose of this study was to validate this system, and to determine the diagnostic performance both overall and per disease severity. METHODS: In total, 250 participants were recruited, based on diagnosis of (n = 125) or absence of PAD (n = 125) from general practice registers. Right and left legs per subject were handled as independent readings, determining actual PAD status via ankle brachial pressure index (ABPI) < 0.9, and then further grading disease severity using suggested ABPI ranges. Data were excluded if no corresponding ABPI value was obtained per DUS determination or if the ABPI reading was > 1.4, owing to the risk of false negatives due to incompressible vessels. Diagnostic sensitivity and specificity were obtained overall, and per severity classification. Furthermore, inter-rater agreement between ABPI and DUS determined PAD severity was determined by linear weighted Cohen's kappa. RESULTS: The sensitivity and specificity in the detection of disease overall was 81.0% (95% confidence interval [CI] 73.4 - 87.2) and 86.3% (95% CI 82.3 - 89.8), respectively. From mild to severe PAD, sensitivity increased from 71.1% (95% CI 55.7 - 83.6) to 89.3% (95% CI 71.8 - 97.7). Furthermore, a Cohen's kappa value of 0.63 (95% CI 0.57 - 0.69) was obtained, indicating moderate agreement between the two diagnostic methods. CONCLUSION: The findings of this study validate the diagnostic performance of the standardised DUS scoring system, as well as its capacity to grade severity of disease, offering a potential tool for the identification of PAD in community/research settings following initial screening methods. Confirmatory work could include a comparison of DUS determined disease with gold standard methods of non-invasive angiography, and novel tools such as toe flex near infrared spectroscopy and multisite photoplethysmography.


Subject(s)
Peripheral Arterial Disease , Humans , Predictive Value of Tests , Peripheral Arterial Disease/diagnostic imaging , Ultrasonography, Doppler, Duplex , Ankle Brachial Index , Sensitivity and Specificity
8.
Cochrane Database Syst Rev ; 1: CD005258, 2022 01 28.
Article in English | MEDLINE | ID: mdl-35089599

ABSTRACT

BACKGROUND: It is generally assumed by practitioners and guideline authors that combined modalities (methods of treatment) are more effective than single modalities in preventing venous thromboembolism (VTE), defined as deep vein thrombosis (DVT) or pulmonary embolism (PE), or both. This is the second update of the review first published in 2008. OBJECTIVES: The aim of this review was to assess the efficacy of combined intermittent pneumatic leg compression (IPC) and pharmacological prophylaxis compared to single modalities in preventing VTE. SEARCH METHODS: The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL, and AMED databases, and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 18 January 2021. We searched the reference lists of relevant articles for additional studies.  SELECTION CRITERIA: We included randomised controlled trials (RCTs) or controlled clinical trials (CCTs) of combined IPC and pharmacological interventions used to prevent VTE compared to either intervention individually. DATA COLLECTION AND ANALYSIS: We independently selected studies, applied Cochrane's risk of bias tool, and extracted data. We resolved disagreements by discussion. We performed fixed-effect model meta-analyses with odds ratios (ORs) and 95% confidence intervals (CIs). We used a random-effects model when there was heterogeneity. We assessed the certainty of the evidence using GRADE. The outcomes of interest were PE, DVT, bleeding and major bleeding. MAIN RESULTS: We included a total of 34 studies involving 14,931 participants, mainly undergoing surgery or admitted with trauma. Twenty-five studies were RCTs (12,672 participants) and nine were CCTs (2259 participants). Overall, the risk of bias was mostly unclear or high. We used GRADE to assess the certainty of the evidence and this was downgraded due to the risk of bias, imprecision or indirectness. The addition of pharmacological prophylaxis to IPC compared with IPC alone reduced the incidence of symptomatic PE from 1.34% (34/2530) in the IPC group to 0.65% (19/2932) in the combined group (OR 0.51, 95% CI 0.29 to 0.91; 19 studies, 5462 participants, low-certainty evidence). The incidence of DVT was 3.81% in the IPC group and 2.03% in the combined group showing a reduced incidence of DVT in favour of the combined group (OR 0.51, 95% CI 0.36 to 0.72; 18 studies, 5394 participants, low-certainty evidence). The addition of pharmacological prophylaxis to IPC, however, increased the risk of any bleeding compared to IPC alone: 0.95% (22/2304) in the IPC group and 5.88% (137/2330) in the combined group (OR 6.02, 95% CI 3.88 to 9.35; 13 studies, 4634 participants, very low-certainty evidence). Major bleeding followed a similar pattern: 0.34% (7/2054) in the IPC group compared to 2.21% (46/2079) in the combined group (OR 5.77, 95% CI 2.81 to 11.83; 12 studies, 4133 participants, very low-certainty evidence). Tests for subgroup differences between orthopaedic and non-orthopaedic surgery participants were not possible for PE incidence as no PE events were reported in the orthopaedic subgroup. No difference was detected between orthopaedic and non-orthopaedic surgery participants for DVT incidence (test for subgroup difference P = 0.19).  The use of combined IPC and pharmacological prophylaxis modalities compared with pharmacological prophylaxis alone reduced the incidence of PE from 1.84% (61/3318) in the pharmacological prophylaxis group to 0.91% (31/3419) in the combined group (OR 0.46, 95% CI 0.30 to 0.71; 15 studies, 6737 participants, low-certainty evidence). The incidence of DVT was 9.28% (288/3105) in the pharmacological prophylaxis group and 5.48% (167/3046) in the combined group (OR 0.38, 95% CI 0.21 to 0.70; 17 studies; 6151 participants, high-certainty evidence). Increased bleeding side effects were not observed for IPC when it was added to anticoagulation (any bleeding: OR 0.87, 95% CI 0.56 to 1.35, 6 studies, 1314 participants, very low-certainty evidence; major bleeding: OR 1.21, 95% CI 0.35 to 4.18, 5 studies, 908 participants, very low-certainty evidence). No difference was detected between the orthopaedic and non-orthopaedic surgery participants for PE incidence (test for subgroup difference P = 0.82) or for DVT incidence (test for subgroup difference P = 0.69). AUTHORS' CONCLUSIONS: Evidence suggests that combining IPC with pharmacological prophylaxis, compared to IPC alone reduces the incidence of both PE and DVT (low-certainty evidence). Combining IPC with pharmacological prophylaxis, compared to pharmacological prophylaxis alone, reduces the incidence of both PE (low-certainty evidence) and DVT (high-certainty evidence). We downgraded due to risk of bias in study methodology and imprecision. Very low-certainty evidence suggests that the addition of pharmacological prophylaxis to IPC increased the risk of bleeding compared to IPC alone, a side effect not observed when IPC is added to pharmacological prophylaxis (very low-certainty evidence), as expected for a physical method of thromboprophylaxis. The certainty of the evidence for bleeding was downgraded to very low due to risk of bias in study methodology, imprecision and indirectness. The results of this update agree with current guideline recommendations, which support the use of combined modalities in hospitalised people (limited to those with trauma or undergoing surgery) at risk of developing VTE. More studies on the role of combined modalities in VTE prevention are needed to provide evidence for specific patient groups and to increase our certainty in the evidence.


Subject(s)
Pulmonary Embolism , Venous Thromboembolism , Anticoagulants/therapeutic use , Hemorrhage , Humans , Leg , Pulmonary Embolism/prevention & control , Venous Thromboembolism/prevention & control
9.
Cochrane Database Syst Rev ; 10: CD010837, 2021 10 01.
Article in English | MEDLINE | ID: mdl-34597414

ABSTRACT

BACKGROUND: Venous thromboembolism (VTE) is a collective term for two conditions: deep vein thrombosis (DVT) and pulmonary embolism (PE). A proportion of people with VTE have no underlying or immediately predisposing risk factors and the VTE is referred to as unprovoked. Unprovoked VTE can often be the first clinical manifestation of an underlying malignancy. This has raised the question of whether people with an unprovoked VTE should be investigated for an underlying cancer. Treatment for VTE is different in cancer and non-cancer patients and a correct diagnosis would ensure that people received the optimal treatment for VTE to prevent recurrence and further morbidity. Furthermore, an appropriate cancer diagnosis at an earlier stage could avoid the risk of cancer progression and lead to improvements in cancer-related mortality and morbidity. This is the third update of the review first published in 2015. OBJECTIVES: To determine whether testing for undiagnosed cancer in people with a first episode of unprovoked VTE (DVT of the lower limb or PE) is effective in reducing cancer- or VTE-related mortality and morbidity and to determine which tests for cancer are best at identifying treatable cancers early. SEARCH METHODS: The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 5 May 2021. We also undertook reference checking to identify additional studies. SELECTION CRITERIA: Randomised and quasi-randomised trials in which people with an unprovoked VTE were allocated to receive specific tests for identifying cancer or clinically indicated tests only were eligible for inclusion. DATA COLLECTION AND ANALYSIS: Two review authors independently selected studies, assessed risk of bias and extracted data. We assessed the certainty of the evidence using GRADE criteria. We resolved any disagreements by discussion. The main outcomes of interest were all-cause mortality, cancer-related mortality and VTE-related mortality. MAIN RESULTS: No new studies were identified for this 2021 update. In total, four studies with 1644 participants are included. Two studies assessed the effect of extensive tests including computed tomography (CT) scanning versus tests at the physician's discretion, while the other two studies assessed the effect of standard testing plus positron emission tomography (PET)/CT scanning versus standard testing alone. For extensive tests including CT versus tests at the physician's discretion, the certainty of the evidence, as assessed according to GRADE, was low due to risk of bias (early termination of the studies). When comparing standard testing plus PET/CT scanning versus standard testing alone, the certainty of evidence was moderate due to a risk of detection bias. The certainty of the evidence was downgraded further as detection bias was present in one study with a low number of events. When comparing extensive tests including CT versus tests at the physician's discretion, pooled analysis on two studies showed that testing for cancer was consistent with either benefit or no benefit on cancer-related mortality (odds ratio (OR) 0.49, 95% confidence interval (CI) 0.15 to 1.67; 396 participants; 2 studies; low-certainty evidence). One study (201 participants) showed that, overall, malignancies were less advanced at diagnosis in extensively tested participants than in participants in the control group. In total, 9/13 participants diagnosed with cancer in the extensively tested group had a T1 or T2 stage malignancy compared to 2/10 participants diagnosed with cancer in the control group (OR 5.00, 95% CI 1.05 to 23.76; low-certainty evidence). There was no clear difference in detection of advanced stages between extensive tests versus tests at the physician's discretion: one participant in the extensively tested group had stage T3 compared with four participants in the control group (OR 0.25, 95% CI 0.03 to 2.28; low-certainty evidence). In addition, extensively tested participants were diagnosed earlier than control group (mean: 1 month with extensive tests versus 11.6 months with tests at physician's discretion to cancer diagnosis from the time of diagnosis of VTE). Extensive testing did not increase the frequency of an underlying cancer diagnosis (OR 1.32, 95% CI 0.59 to 2.93; 396 participants; 2 studies; low-certainty evidence). Neither study measured all-cause mortality, VTE-related morbidity and mortality, complications of anticoagulation, adverse effects of cancer tests, participant satisfaction or quality of life. When comparing standard testing plus PET/CT screening versus standard testing alone, standard testing plus PET/CT screening was consistent with either benefit or no benefit on all-cause mortality (OR 1.22, 95% CI 0.49 to 3.04; 1248 participants; 2 studies; moderate-certainty evidence), cancer-related mortality (OR 0.55, 95% CI 0.20 to 1.52; 1248 participants; 2 studies; moderate-certainty evidence) or VTE-related morbidity (OR 1.02, 95% CI 0.48 to 2.17; 854 participants; 1 study; moderate-certainty evidence). Regarding stage of cancer, there was no clear difference for detection of early (OR 1.78, 95% 0.51 to 6.17; 394 participants; 1 study; low-certainty evidence) or advanced (OR 1.00, 95% CI 0.14 to 7.17; 394 participants; 1 study; low-certainty evidence) stages of cancer. There was also no clear difference in the frequency of an underlying cancer diagnosis (OR 1.71, 95% CI 0.91 to 3.20; 1248 participants; 2 studies; moderate-certainty evidence). Time to cancer diagnosis was 4.2 months in the standard testing group and 4.0 months in the standard testing plus PET/CT group (P = 0.88). Neither study measured VTE-related mortality, complications of anticoagulation, adverse effects of cancer tests, participant satisfaction or quality of life. AUTHORS' CONCLUSIONS: Specific testing for cancer in people with unprovoked VTE may lead to earlier diagnosis of cancer at an earlier stage of the disease. However, there is currently insufficient evidence to draw definitive conclusions concerning the effectiveness of testing for undiagnosed cancer in people with a first episode of unprovoked VTE (DVT or PE) in reducing cancer- or VTE-related morbidity and mortality. The results could be consistent with either benefit or no benefit. Further good-quality large-scale randomised controlled trials are required before firm conclusions can be made.


Subject(s)
Neoplasms , Venous Thromboembolism , Humans , Morbidity , Neoplasms/complications , Positron Emission Tomography Computed Tomography , Quality of Life , Venous Thromboembolism/etiology
10.
Cochrane Database Syst Rev ; 8: CD005624, 2021 08 11.
Article in English | MEDLINE | ID: mdl-34378180

ABSTRACT

BACKGROUND: Great saphenous vein (GSV) incompetence, causing varicose veins and venous insufficiency, makes up the majority of lower-limb superficial venous diseases. Treatment options for GSV incompetence include surgery (also known as high ligation and stripping), laser and radiofrequency ablation, and ultrasound-guided foam sclerotherapy. Newer treatments include cyanoacrylate glue, mechanochemical ablation, and endovenous steam ablation. These techniques avoid the need for a general anaesthetic, and may result in fewer complications and improved quality of life (QoL). These treatments should be compared to inform decisions on treatment for varicosities in the GSV. This is an update of a Cochrane Review first published in 2011. OBJECTIVES: To assess the effects of endovenous laser ablation (EVLA), radiofrequency ablation (RFA), endovenous steam ablation (EVSA), ultrasound-guided foam sclerotherapy (UGFS), cyanoacrylate glue, mechanochemical ablation (MOCA) and high ligation and stripping (HL/S) for the treatment of varicosities of the great saphenous vein (GSV). SEARCH METHODS: The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL, and AMED databases, and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 2 November 2020. We undertook reference checking to identify additional studies. SELECTION CRITERIA: We included randomised controlled trials (RCTs) treating participants for varicosities of the GSV using EVLA, RFA, EVSA, UGFS, cyanoacrylate glue, MOCA or HL/S. Key outcomes of interest are technical success, recurrence, complications and QoL. DATA COLLECTION AND ANALYSIS: Two review authors independently selected trials, applied Cochrane's risk of bias tool, and extracted data. We calculated odds ratios (ORs) with 95% confidence intervals (CIs) and assessed the certainty of evidence using GRADE. MAIN RESULTS: We identified 11 new RCTs for this update. Therefore, we included 24 RCTs with 5135 participants. Duration of follow-up ranged from five weeks to eight years. Five comparisons included single trials. For comparisons with more than one trial, we could only pool data for 'technical success' and 'recurrence' due to heterogeneity in outcome definitions and time points reported. All trials had some risk of bias concerns. Here we report the clinically most relevant comparisons. EVLA versus RFA Technical success was comparable up to five years (OR 0.98, 95% CI 0.41 to 2.38; 5 studies, 780 participants; moderate-certainty evidence); over five years, there was no evidence of a difference (OR 0.85, 95% CI 0.30 to 2.41; 1 study, 291 participants; low-certainty evidence). One study reported recurrence, showing no clear difference at three years (OR 1.53, 95% CI 0.78 to 2.99; 291 participants; low-certainty evidence), but a benefit for RFA may be seen at five years (OR 2.77, 95% CI 1.52 to 5.06; 291 participants; low-certainty evidence). EVLA versus UGFS Technical success may be better in EVLA participants up to five years (OR 6.13, 95% CI 0.98 to 38.27; 3 studies, 588 participants; low-certainty evidence), and over five years (OR 6.47, 95% CI 2.60 to 16.10; 3 studies, 534 participants; low-certainty evidence). There was no clear difference in recurrence up to three years and at five years (OR 0.68, 95% CI 0.20 to 2.36; 2 studies, 443 participants; and OR 1.08, 95% CI 0.40 to 2.87; 2 studies, 418 participants; very low-certainty evidence, respectively). EVLA versus HL/S Technical success may be better in EVLA participants up to five years (OR 2.31, 95% CI 1.27 to 4.23; 6 studies, 1051 participants; low-certainty evidence). No clear difference in technical success was seen at five years and beyond (OR 0.93, 95% CI 0.57 to 1.50; 5 studies, 874 participants; low-certainty evidence). Recurrence was comparable within three years and at 5 years (OR 0.78, 95% CI 0.47 to 1.29; 7 studies, 1459 participants; and OR 1.09, 95% CI 0.68 to 1.76; 7 studies, 1267 participants; moderate-certainty evidence, respectively). RFA versus MOCA There was no clear difference in technical success (OR 1.76, 95% CI 0.06 to 54.15; 3 studies, 435 participants; low-certainty evidence), or recurrence (OR 1.00, 95% CI 0.21 to 4.81; 3 studies, 389 participants; low-certainty evidence). Long-term data are not available. RFA versus HL/S No clear difference in technical success was detected up to five years (OR 5.71, 95% CI 0.64 to 50.81; 2 studies, 318 participants; low-certainty evidence); over five years, there was no evidence of a difference (OR 0.88, 95% CI 0.29 to 2.69; 1 study, 289 participants; low-certainty evidence). No clear difference in recurrence was detected up to three years (OR 0.93, 95% CI 0.58 to 1.51; 4 studies, 546 participants; moderate-certainty evidence); but a possible long-term benefit for RFA was seen (OR 0.41, 95% CI 0.22 to 0.75; 1 study, 289 participants; low-certainty evidence). UGFS versus HL/S Meta-analysis showed a possible benefit for HL/S compared with UGFS in technical success up to five years (OR 0.32, 95% CI 0.11 to 0.94; 4 studies, 954 participants; low-certainty evidence), and over five years (OR 0.09, 95% CI 0.03 to 0.30; 3 studies, 525 participants; moderate-certainty evidence). No clear difference was detected in recurrence up to three years (OR 1.81, 95% CI 0.87 to 3.77; 3 studies, 822 participants; low-certainty evidence), and after five years (OR 1.24, 95% CI 0.57 to 2.71; 3 studies, 639 participants; low-certainty evidence). Complications were generally low for all interventions, but due to different definitions and time points, we were unable to draw conclusions (very-low certainty evidence). Similarly, most studies evaluated QoL but used different questionnaires at variable time points. Rates of QoL improvement were comparable between interventions at follow-up (moderate-certainty evidence). AUTHORS' CONCLUSIONS: Our conclusions are limited due to the relatively small number of studies for each comparison and differences in outcome definitions and time points reported. Technical success was comparable between most modalities. EVLA may offer improved technical success compared to UGFS or HL/S. HL/S may have improved technical success compared to UGFS. No evidence of a difference was detected in recurrence, except for a possible long-term benefit for RFA compared to EVLA or HL/S. Studies which provide more evidence on the breadth of treatments are needed. Future trials should seek to standardise clinical terminology of outcome measures and the time points at which they are measured.


Subject(s)
Catheter Ablation , Saphenous Vein/surgery , Sclerotherapy/methods , Varicose Veins/surgery , Venous Insufficiency/surgery , Female , Humans , Male , Randomized Controlled Trials as Topic , Saphenous Vein/pathology
11.
JRSM Open ; 12(5): 20542704211001220, 2021 May.
Article in English | MEDLINE | ID: mdl-34104452

ABSTRACT

Femoral venous aneurysms are a rare disease entity, yet they carry the risk of significant mortality due to venous thromboembolism, as demonstrated by a case report of an otherwise fit and well 74-year-old gentleman.

12.
Cochrane Database Syst Rev ; 6: CD003748, 2021 06 30.
Article in English | MEDLINE | ID: mdl-34192807

ABSTRACT

BACKGROUND: Peripheral arterial disease (PAD) affects between 4% and 12% of people aged 55 to 70 years, and 20% of people over 70 years. A common complaint is intermittent claudication (exercise-induced lower limb pain relieved by rest). These patients have a three- to six-fold increase in cardiovascular mortality.  Cilostazol is a drug licensed for the use of improving claudication distance and, if shown to reduce cardiovascular risk, could offer additional clinical benefits. This is an update of the review first published in 2007. OBJECTIVES: To determine the effect of cilostazol on initial and absolute claudication distances, mortality and vascular events in patients with stable intermittent claudication. SEARCH METHODS: The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL, and AMED databases, and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registries, on 9 November 2020. SELECTION CRITERIA: We considered double-blind, randomised controlled trials (RCTs) of cilostazol versus placebo, or versus other drugs used to improve claudication distance in patients with stable intermittent claudication. DATA COLLECTION AND ANALYSIS: Two authors independently assessed trials for selection and independently extracted data. Disagreements were resolved by discussion. We assessed the risk of bias with the Cochrane risk of bias tool. Certainty of the evidence was evaluated using GRADE. For dichotomous outcomes, we used odds ratios (ORs) with corresponding 95% confidence intervals (CIs) and for continuous outcomes we used mean differences (MDs) and 95% CIs. We pooled data using a fixed-effect model, or a random-effects model when heterogeneity was identified. Primary outcomes were initial claudication distance (ICD) and quality of life (QoL). Secondary outcomes were absolute claudication distance (ACD), revascularisation, amputation, adverse events and cardiovascular events. MAIN RESULTS: We included 16 double-blind, RCTs (3972 participants) comparing cilostazol with placebo, of which five studies also compared cilostazol with pentoxifylline. Treatment duration ranged from six to 26 weeks. All participants had intermittent claudication secondary to PAD. Cilostazol dose ranged from 100 mg to 300 mg; pentoxifylline dose ranged from 800 mg to 1200 mg. The certainty of the evidence was downgraded by one level for all studies because publication bias was strongly suspected. Other reasons for downgrading were imprecision, inconsistency and selective reporting. Cilostazol versus placebo Participants taking cilostazol had a higher ICD compared with those taking placebo (MD 26.49 metres; 95% CI 18.93 to 34.05; 1722 participants; six studies; low-certainty evidence). We reported QoL measures descriptively due to insufficient statistical detail within the studies to combine the results; there was a possible indication in improvement of QoL in the cilostazol treatment groups (low-certainty evidence). Participants taking cilostazol had a higher ACD compared with those taking placebo (39.57 metres; 95% CI 21.80 to 57.33; 2360 participants; eight studies; very-low certainty evidence). The most commonly reported adverse events were headache, diarrhoea, abnormal stools, dizziness, pain and palpitations. Participants taking cilostazol had an increased odds of experiencing headache compared to participants taking placebo (OR 2.83; 95% CI 2.26 to 3.55; 2584 participants; eight studies; moderate-certainty evidence).Very few studies reported on other outcomes so conclusions on revascularisation, amputation, or cardiovascular events could not be made. Cilostazol versus pentoxifylline There was no difference detected between cilostazol and pentoxifylline for improving walking distance, both in terms of ICD (MD 20.0 metres, 95% CI -2.57 to 42.57; 417 participants; one study; low-certainty evidence); and ACD (MD 13.4 metres, 95% CI -43.50 to 70.36; 866 participants; two studies; very low-certainty evidence). One study reported on QoL; the study authors reported no difference in QoL between the treatment groups (very low-certainty evidence). No study reported on revascularisation, amputation or cardiovascular events. Cilostazol participants had an increased odds of experiencing headache compared with participants taking pentoxifylline at 24 weeks (OR 2.20, 95% CI 1.16 to 4.17; 982 participants; two studies; low-certainty evidence). AUTHORS' CONCLUSIONS: Cilostazol has been shown to improve walking distance in people with intermittent claudication. However, participants taking cilostazol had higher odds of experiencing headache. There is insufficient evidence about the effectiveness of cilostazol for serious events such as amputation, revascularisation, and cardiovascular events. Despite the importance of QoL to patients, meta-analysis could not be undertaken because of differences in measures used and reporting. Very limited data indicated no difference between cilostazol and pentoxifylline for improving walking distance and data were too limited for any conclusions on other outcomes.


Subject(s)
Cilostazol/therapeutic use , Intermittent Claudication/drug therapy , Platelet Aggregation Inhibitors/therapeutic use , Tetrazoles/therapeutic use , Aged , Bias , Humans , Intermittent Claudication/etiology , Middle Aged , Myocardial Infarction/prevention & control , Pentoxifylline/therapeutic use , Peripheral Vascular Diseases/complications , Peripheral Vascular Diseases/drug therapy , Placebos/therapeutic use , Platelet Aggregation Inhibitors/adverse effects , Randomized Controlled Trials as Topic , Stroke/prevention & control , Tetrazoles/adverse effects , Walking
13.
Access Microbiol ; 3(1): acmi000183, 2021.
Article in English | MEDLINE | ID: mdl-33997614

ABSTRACT

Lawsonella clevelandensis is an anaerobic, partially acid-fast, Gram-positive bacillus associated with abscess formation. We present the case of a 70-year-old male with chronic contained rupture of abdominal aortic aneurysm (CCR-AAA) complicated by intra-abdominal abscess formation. An abdominal computed tomography scan revealed a rim-enhancing retroperitoneal collection tracking into the subcutaneous layer of the left flank and buttock, suggestive of CCR-AAA with infected haematoma. He underwent ultrasound-guided needle aspiration of the intra-abdominal collection. Conventional culture techniques failed to isolate L. clevelandensis , and the diagnosis was only confirmed by means of 16S rRNA PCR. The patient underwent branched endovascular repair of his aneurysm, and was commenced on treatment with co-amoxiclav, resulting in significant reduction in the size of the infected collection. This is only the second reported case of infection with L. clevelandensis in the UK, and the first reported case of this organism causing infected CCR-AAA.

14.
Physiol Meas ; 42(5)2021 06 17.
Article in English | MEDLINE | ID: mdl-33878743

ABSTRACT

Objective.A proof-of-concept study to assess the potential of a deep learning (DL) based photoplethysmography PPG ('DLPPG') classification method to detect peripheral arterial disease (PAD) using toe PPG signals.Approach.PPG spectrogram images derived from our previously published multi-site PPG datasets (214 participants; 31.3% legs with PAD by ankle brachial pressure index (ABPI)) were input into a pretrained 8-layer (five convolutional layers + three fully connected layers) AlexNet as tailored to the 2-class problem with transfer learning to fine tune the convolutional neural network (CNN).k-fold random cross validation (CV) was performed (fork = 5 andk = 10), with each evaluated over k training/validation runs. Overall test sensitivity, specificity, accuracy, and Cohen's Kappa statistic with 95% confidence interval ranges were calculated and compared, as well as sensitivities in detecting mild-moderate (0.5 ≤ ABPI < 0.9) and major (ABPI < 0.5) levels of PAD.Main results.CV with eitherk = 5 or 10 folds gave similar diagnostic performances. The overall test sensitivity was 86.6%, specificity 90.2% and accuracy 88.9% (Kappa: 0.76 [0.70-0.82]) (atk= 5). The sensitivity to mild-moderate disease was 83.0% (75.5%-88.9%) and to major disease was 100.0% (90.5%-100.0%).Significance.Substantial agreements have been demonstrated between the DL-based PPG classification technique and the ABPI PAD diagnostic reference. This novel automatic approach, requiring minimal pre-processing of the pulse waveforms before PPG trace classification, could offer significant benefits for the diagnosis of PAD in a variety of clinical settings where low-cost, portable and easy-to-use diagnostics are desirable.


Subject(s)
Deep Learning , Peripheral Arterial Disease , Heart Rate , Humans , Leg , Peripheral Arterial Disease/diagnosis , Photoplethysmography
15.
Angiology ; 72(5): 474-479, 2021 May.
Article in English | MEDLINE | ID: mdl-33401955

ABSTRACT

The Edinburgh Claudication Questionnaire (ECQ) was developed to help identify peripheral arterial disease (PAD) in the general population but has not been validated against diagnostic arterial imaging methods such as Duplex Vascular Ultrasound Scanning (DUS). In the present study, we assessed the accuracy of the ECQ for diagnosis using DUS. As part of a National Institute of Health Research funded project looking at novel diagnostic methods, 250 patients were studied from 15 general practices across North East England from May 2015 and November 2016. Practices identified those with a PAD diagnosis from their registers as well as age- and sex-matched controls. All the ECQs were recorded by a vascular specialist nurse. Duplex vascular ultrasound scanning was used as a reference standard for the diagnosis of occlusive PAD. The ECQ had a sensitivity of 52.5% (95% CI: 42.3%-62.5%), specificity of 87.1% (95% CI: 80.6%-92.0%), positive likelihood ratio of 4.06 (95% CI: 2.57-6.42), and negative likelihood ratio of 0.55 (95% CI: 0.44-0.68) compared with reference standard DUS. The ECQ has relatively poor overall diagnostic test accuracy in isolation. It may be helpful in ruling out PAD or as a supplementary test to improve diagnosis of symptomatic disease in General Practice.


Subject(s)
General Practice , Intermittent Claudication/diagnosis , Peripheral Arterial Disease/diagnosis , Primary Health Care , Surveys and Questionnaires , Aged , Aged, 80 and over , Case-Control Studies , England , Female , Humans , Male , Middle Aged , Predictive Value of Tests , Reproducibility of Results , Ultrasonography, Doppler, Duplex
17.
Health Technol Assess ; 24(69): 1-80, 2020 12.
Article in English | MEDLINE | ID: mdl-33275096

ABSTRACT

BACKGROUND: Patients admitted to hospital for surgery are at an increased risk of venous thromboembolism. Pharmaco-thromboprophylaxis and mechanical prophylaxis (usually graduated compression stockings or intermittent pneumatic compression) have been shown to reduce the incidence of venous thromboembolism. The evidence base supporting the National Institute for Health and Care Excellence's recommendation for the use of graduated compression stockings for venous thromboembolism prevention in the UK has recently been challenged. It is unclear if the risks and costs associated with graduated compression stockings are justified for deep-vein thrombosis prevention in moderate- and high-risk elective surgical inpatients receiving low-dose low-molecular-weight heparin pharmaco-thromboprophylaxis. OBJECTIVES: The primary objective was to compare the venous thromboembolism rate in elective surgical inpatients at moderate or high risk of venous thromboembolism who were receiving either graduated compression stockings and low-dose low-molecular-weight heparin (standard care) or low-dose low-molecular-weight heparin alone (intervention). DESIGN: This was a pragmatic, multicentre, prospective, non-inferiority, randomised controlled trial. SETTING: This took place in secondary care NHS hospitals in the UK. PARTICIPANTS: Patients aged ≥ 18 years who were assessed to be at moderate or high risk of venous thromboembolism according to the NHS England venous thromboembolism risk assessment tool (or the trust equivalent based on this form) and who were not contraindicated to low-molecular-weight heparin or graduated compression stockings were deemed eligible to take part. INTERVENTIONS: Participants were randomised 1 : 1 to either low-molecular-weight heparin or low-molecular-weight heparin and graduated compression stockings. MAIN OUTCOME MEASURES: The primary outcome measure was venous thromboembolism up to 90 days after surgery. A combined end point of duplex ultrasound-proven new lower-limb deep-vein thrombosis (symptomatic or asymptomatic) plus imaging-confirmed symptomatic pulmonary embolism. Secondary outcomes included quality of life, compliance with graduated compression stockings and low-molecular-weight heparin during admission, and all-cause mortality. RESULTS: A total of 1905 participants were randomised and 1858 were included in the intention-to-treat analysis. A primary outcome event occurred in 16 out of 937 (1.7%) patients in the low-molecular-weight heparin-alone arm compared with 13 out of 921 (1.4%) patients in the low-molecular-weight heparin plus graduated compression stockings arm. The risk difference between low-molecular-weight heparin and low-molecular-weight heparin plus graduated compression stockings was 0.30% (95% confidence interval -0.65% to 1.26%). As the 95% confidence interval did not cross the non-inferiority margin of 3.5% (p < 0.001 for non-inferiority), the results indicate that non-inferiority of low-molecular-weight heparin alone was shown. LIMITATIONS: In total, 13% of patients did not receive a duplex ultrasound scan that could have detected further asymptomatic deep-vein thrombosis. However, missing scans were balanced between both trial arms. The subpopulation of those aged ≥ 65 years assessed as being at a moderate risk of venous thromboembolism was under-represented in the study; however, this reflects that this group is under-represented in the general population. CONCLUSIONS: For elective surgical patients at moderate or high risk of venous thromboembolism, administration of pharmaco-thromboprophylaxis alone is non-inferior to a combination of pharmaco-thromboprophylaxis and graduated compression stockings. These findings indicate that graduated compression stockings may be unnecessary for most elective surgical patients. FUTURE WORK: Further studies are required to evaluate whether or not adjuvant graduated compression stockings have a role in patients receiving extended thromboprophylaxis, beyond the period of hospital admission, following elective surgery or in patients undergoing emergency surgical procedures. TRIAL REGISTRATION: Current Controlled Trials ISRCTN13911492. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 69. See the NIHR Journals Library website for further project information.


WHY DID WE CONDUCT THIS RESEARCH?: People undergoing operations are at risk of developing blood clots in their legs, which is known as a deep-vein thrombosis. Blood clots occur for several reasons, such as not being able to move around after an operation, changes in the blood or damage to the veins in which blood travels. To decrease the risk of getting deep-vein thrombosis, patients having operations are given tight elastic socks to wear called graduated compression stockings. They are also given blood thinning medicine to prevent clotting. There is little evidence that wearing elastic socks in hospital will reduce the risk of blood clots if blood thinners are also given. Many patients say that the socks can hurt or cause bruising and can be difficult to put on. The graduated compression as an adjunct to thromboprophylaxis in surgery (GAPS) trial investigated whether or not patients having an operation would benefit from wearing elastic socks as well as getting blood thinners, or if blood thinners on their own prevented blood clots. WHAT DID WE DO?: A total of 1905 patients who were having operations at seven hospitals in England agreed to take part. They were randomly assigned to different treatments by a computer program. Half of the patients were given elastic socks plus blood thinners, and the other half were given the blood thinners alone. WHAT DID WE FIND?: There was no significant difference in the number of people who had a blood clot in either study group. This could mean that blood thinners are as good at stopping blood clots as blood thinners and elastic socks for patients having operations. WHAT COULD BE CARRIED OUT NEXT?: The NHS spends around £63M per year across England on elastic stockings. This research indicates that patients might not get extra benefit from wearing them if they have taken blood thinners.


Subject(s)
Anticoagulants/therapeutic use , Heparin, Low-Molecular-Weight/therapeutic use , Inpatients , Stockings, Compression , Venous Thromboembolism/prevention & control , Aged , Elective Surgical Procedures , Female , Humans , Male , Middle Aged , Risk Factors , United Kingdom
18.
Physiol Meas ; 41(7): 074001, 2020 08 11.
Article in English | MEDLINE | ID: mdl-32784270

ABSTRACT

OBJECTIVE: It is accepted that changes in the peripheral pulse waveform characteristics occur with ageing. Pulse risetime is one important feature which has clinical value. However, it is unclear how it varies across the full age spectrum from child to senior and for different peripheral measurement sites. The objectives of this study were to determine the association between age and pulse risetime characteristics over an 8-decade age range at the ears, fingers, and toes, and to consider effects arising from differences in systolic blood pressure (SBP), height and heart rate. APPROACH: Multi-site photoplethysmography (MPPG) pulse waveforms were recorded non-invasively from the right and left ears, fingers, and toes of 304 normal healthy human subjects (range 6-87 years; 156 male and 148 female). SBP, height, and heart rate were also measured. Multi-site PPG pulse risetimes, and their site differences, were determined. MAIN RESULTS: Univariate regression analysis showed positive correlations with risetime for age (ears, fingers and toes: + 0.8, + 1.9, and + 1.1 ms/year, respectively), SBP (+0.5, + 1.3, and + 0.9 ms/mmHg) and height (+0.5, + 1.2, and + 1.0 ms/cm), but with a clear inverse association with heart rate (-1.8, - 2.5, and - 1.6 ms min) (P < 0.0001). No significant differences between male and female subjects were found for pulse risetime. SIGNIFICANCE: Normative multi-site PPG risetime characteristics have been defined in over 300 subjects and are shown to increase with age linearly up to the 8th decade. In contrast, we have shown that heart rate has a clear inverse relationship with risetime for all measurement sites.


Subject(s)
Aging , Heart Rate , Photoplethysmography , Adolescent , Adult , Aged , Aged, 80 and over , Child , Ear , Female , Fingers , Humans , Male , Middle Aged , Pulse , Toes , Young Adult
19.
Cureus ; 12(3): e7486, 2020 Mar 31.
Article in English | MEDLINE | ID: mdl-32351863

ABSTRACT

Introduction The ability to undertake simple practical procedures is essential for graduating medical students and is typically assessed using simulated models. Feedback is a key component of the learning process in developing proficiency in these key skills. Video feedback (VF) has previously shown promise, however, negative effects of VF-related anxiety on performance have been previously reported. Our aim was to investigate for a difference in participant anxiety between supervised individualised video feedback (SIVF) and unsupervised generic video feedback (UGVF) when undertaking simulated basic practical procedures. Methods Undergraduate medical students participating in a clinical skills study to compare UGVF and SIVF completed a Likert scale questionnaire detailing perceived anxiety. During the study, students were recorded performing three basic surgical skills (simple interrupted suturing, intravenous cannulation, urinary catheterisation). Feedback was then provided by one of two methods: (1) SIVF - participant video footage reviewed together with a tutor providing targeted feedback, and (2) UGVF - participant video footage reviewed alone with concurrent access to a generic pre-recorded 'expert tips' video clip for comparison. Each participant received SIVF and UGVF at least once. Results The majority of participants did not find either SIVF (81.7%) or UGVF (78.8%) stressful. Students had a strong preference for SIVF (77.5%) and disagreed that similar 'face-to-face' feedback had impaired learning in the past (80.3%). Conclusion Medical student-perceived anxiety is negligible when video feedback is employed during simulated core practical skill training.

20.
Vascular ; 28(5): 612-618, 2020 Oct.
Article in English | MEDLINE | ID: mdl-32356682

ABSTRACT

OBJECTIVES: Resuscitative endovascular balloon occlusion of the aorta is an alternative to resuscitative thoracotomy in non-compressible torso haemorrhage. Low-profile, compliant balloon catheter systems have been developed, which can be deployed without the need for fluoroscopy. However, concern exists for over inflation and aortic injury, especially as compliant balloon material can stretch reducing syringe feedback and limiting the effectiveness of a safety valve. An alternative material would be a semi-compliant balloon material, but its performance is unknown. The aim of this study was to compare the inflation characteristics of compliant versus semi-compliant balloon systems and to determine whether a pressure relief safety valve can be practically applied to a semi-compliant balloon catheter as a safety device. METHODS: This was an ex vivo study using porcine segments of thoracic aorta. The study consisted of two phases. The first phase involved intermittent inflation of six compliant balloon and six semi-compliant balloon balloons until balloon or aortic rupture. In the second phase, six semi-compliant balloons with the pressure-relief valve set at 0.45 atmospheres were inflated in the aortas until the valve release, followed by injection with additional 30 mL. Data including pressure, volume, balloon working length, diameter and circumferential stretch ratio were collected. RESULTS: At failure, mean balloon volume was almost double in compliant balloon group vs semi-compliant balloon group - 49.83 mL (±23.25) and 25.16 mL (±8.93), respectively (p = 0.004), with 36% increase in working length in the compliant balloon group - 81.17 mm (±19.11) vs 59.49 (±4.86) for semi-compliant balloon (p = 0.023). When plotted, the relationship pattern between volume and pressure fit a linear model for the compliant balloon, and a quadratic model for the semi-compliant balloon. Following attempted over inflation with the pressure valve, there was no change in parameters before and after attempted over inflation. CONCLUSIONS: The inflation profile differs between balloon designs. In contrast to semi-compliant balloons, compliant balloons will accommodate more volume to mitigate increase in pressure. This does not completely eliminate the risk of over inflation. The inflation characteristics of the semi-compliant balloon permit pairing it with a safety valve, which could lead to a development of a safer balloon technology in the future.


Subject(s)
Aorta, Thoracic , Balloon Occlusion/instrumentation , Endovascular Procedures/instrumentation , Vascular Access Devices , Animals , Equipment Design , Equipment Failure Analysis , Pressure , Sus scrofa
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