Endovascular versus open repair of asymptomatic popliteal artery aneurysm.

BACKGROUND: Popliteal artery aneurysm (PAA) is a focal dilatation and weakening of the popliteal artery. If left untreated, the aneurysm may thrombose, rupture or the clot within the aneurysm may embolise causing severe morbidity. PAA may be treated surgically by performing a bypass from the arterial segment proximal to the aneurysm to the arterial segment below the aneurysm, which excludes the aneurysm from the circulation. It may also be treated by a stent graft that is inserted percutaneously or through a small cut in the groin. The success of the procedure is gauged by the ability of the graft to stay patent over an extended duration. While surgical treatment is usually preferred in an emergency, the evidence on first line treatment in a non-emergency setting is unclear. This is an update of a review first published in 2014. OBJECTIVES: To assess the effectiveness of an endovascular stent graft versus conventional open surgery for the treatment of asymptomatic popliteal artery aneurysms (PAA) on primary and assisted patency rates, hospital stay, length of the procedure and local complications. 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 29 January 2019. SELECTION CRITERIA: We included all randomised controlled trials (RCTs) comparing endovascular stent grafting versus conventional open surgical repair in patients undergoing unilateral or bilateral prophylactic repair of asymptomatic PAAs. DATA COLLECTION AND ANALYSIS: We collected data on primary and assisted primary patency rates (primary endpoints) as well as operating time, the length of hospital stay, limb salvage and local wound complications (secondary endpoints). We presented results as risk ratio or mean difference with 95% confidence intervals and assessed the certainty of the evidence using GRADE. MAIN RESULTS: No new studies were identified for this update. A single RCT with a total of 30 PAAs met the inclusion criteria. There was a low risk of selection bias and detection bias. However, the risks of performance bias, attrition bias and reporting bias were unclear from the study. Despite being an RCT, the certainty of the evidence was downgraded to moderate due to the small sample size, resulting in wide confidence intervals (CIs); only 30 PAAs were randomised over a period of five years (15 PAAs each in the groups receiving endovascular stent graft and undergoing conventional open surgery). The primary patency rate at one year was 93.3% in the endovascular group and 100% in the surgery group (RR 0.94, 95% CI 0.78 to 1.12; moderate-certainty evidence). The assisted patency rate at one year was similar in both groups (RR 1.00, 95% CI 0.88 to 1.13; moderate-certainty evidence). There was no clear evidence of a difference between the two groups in the primary or assisted patency rates at four years (13 grafts were patent from 15 PAA treatments in each group; RR 1.00, 95% CI 0.76 to 1.32; moderate-certainty evidence); the effects were imprecise and compatible with the benefit of either endovascular stent graft or surgery or no difference. Mean hospital stay was shorter in the endovascular group (4.3 days for the endovascular group versus 7.7 days for the surgical group; mean difference (MD) -3.40 days, 95% CI -4.42 to -2.38; P < 0.001; moderate-certainty evidence). Mean operating time was also reduced in the endovascular group (75.4 minutes in the endovascular group versus 195.3 minutes in the surgical group; MD -119.90 minutes, 95% CI -137.71 to -102.09; P < 0.001; moderate-certainty evidence). Limb salvage was 100% in both groups. Data on local wound complications were not published in the trial report. AUTHORS' CONCLUSIONS: Evidence to determine the effectiveness of endovascular stent graft versus conventional open surgery for the treatment of asymptomatic PAAs is limited to data from one small study. At one year there is moderate-certainty evidence that primary patency may be improved in the surgery group but assisted primary patency rates were similar between groups. At four years there was no clear benefit from either endovascular stent graft or surgery to primary or assisted primary patency (moderate-certainty evidence). As both operating time and hospital stay were reduced in the endovascular group (moderate-certainty evidence), it may represent a viable alternative to open repair of PAA. A large multicenter RCT may provide more information in the future. However, difficulties in recruiting enough patients are likely, unless it is an international collaboration including a number of high volume vascular centres.

The past, present and future role of artificial intelligence in imaging.

Artificial intelligence (AI) is already widely employed in various medical roles, and ongoing technological advances are encouraging more widespread use of AI in imaging. This is partly driven by the recognition of the significant frequency and clinical impact of human errors in radiology reporting, and the promise that AI can help improve the reliability as well the efficiency of imaging interpretation. AI in imaging was first envisioned in the 1960s, but initial attempts were limited by the technology of the day. It was the introduction of artificial neural networks and AI based computer aided detection (CAD) software in the 1980s that marked the advent of widespread integration of AI within radiology reporting. CAD is now routinely used in mammography, with consistent evidence of equivalent or improved lesion detection, with small increases in recall rates. Significant false positive rates remain a limitation for CAD, although these have markedly improved in the last decade. Other challenges include the difficulty clinicians encounter in trying to understand the reasoning of an AI system, which may limit their confidence in its advice, and a question mark hangs over who should be liable if CAD makes an error. The future integration of CAD with PACS promises the development of more comprehensively intelligent systems that can identify multiple, challenging diagnoses, and a move towards more individualised patient outcome predictions based upon AI analysis.

Depiction of lower limb venous anatomy in patients undergoing interventional deep venous reconstruction-the role of balanced steady state free precession MRI.

OBJECTIVES: This study evaluates the use of balanced steady-state free precession MRI (bSSFP-MRI) in the diagnostic work-up of patients undergoing interventional deep venous reconstruction (I-DVR). Intravenous digital subtraction angiography (IVDSA) was used as the gold-standard for comparison to assess disease extent and severity. METHODS: A retrospective comparison of bSSFP-MRI to IVDSA was performed in all patients undergoing both examinations for treatment planning prior to I-DVR. The severity of disease in each venous segment was graded by two board-certified radiologists working independently, according to a predetermined classification system. RESULTS: In total, 44 patients (225 venous segments) fulfilled the inclusion criteria. A total of 156 abnormal venous segments were diagnosed using bSSFP-MRI compared with 151 using IVDSA. The prevalence of disease was higher in the iliac and femoral segments (range, 79.6-88.6%). Overall sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and the diagnostic ratio for bSSFP-MRI were 99.3%, 91.9%, 12.3, 0.007 and 1700, respectively. CONCLUSION: This study supports the use of non-contrast balanced SSFP-MRI in the assessment of the deep veins of the lower limb prior to I-DVR. The technique offers an accurate, fast and non-invasive alternative to IVDSA. Advances in Knowledge: Although balanced SSFP-MRI is commonly used in cardiac imaging, its use elsewhere is limited and its use in evaluating the deep veins prior to interventional reconstruction is not described. Our study demonstrates the usefulness of this technique in the work-up of patients awaiting interventional venous reconstruction compared with the current gold standard.

Paclitaxel-coated balloons and aneurysm formation in peripheral vessels.

We report two cases of early aneurysmal vessel dilatation after a paclitaxel-coated balloon (PCB) was used for angioplasty of the peripheral vessels. The first case refers to a failing vein bypass with a tight proximal anastomotic stenosis, whereas the second refers to a distal tibial artery occlusion. A PCB was used to treat both patients. Aneurysmal dilatation of the previously treated segment was noted in both patients during subsequent follow-up imaging. In the absence of other causal factors, we attribute both cases to PCB application. The aneurysms that formed had no detrimental effect on the patients' health and required no further treatment; however, it is important to bear in mind this potential risk of presumed paclitaxel toxicity.

Junior doctors' knowledge of applied clinical anatomy.

This study examines the level of knowledge of applied clinical anatomy among junior doctors. A multiple-choice questionnaire was designed, which covered 15 areas of anatomical knowledge essential to clinical practice, for example, important surface landmarks and interpretation of radiographs. The questionnaire was completed by 128 individuals. They comprised anatomy demonstrators, preregistration house officers (PRHOs), senior house officers (SHOs) and specialist registrars (SpRs) across the range of medical and surgical specialities. Answers were scored and analyzed by group, allowing comparison not only between newly qualified PRHOs and more senior doctors, but also with anatomy demonstrators who had undergone more traditional anatomical training. The results reveal a wide variation of knowledge among junior doctors, with PRHOs scoring an average of 72.1%, SHOs 77.1%, SpRs 82.4%, and demonstrators 82.9%. This progression in knowledge up the clinical hierarchy may reflect clinical experience building upon the foundations laid in medical school, although with demonstrators topping the league table, it seems that intensive academic training is the most beneficial. With junior doctors' training in the UK currently in flux, these results highlight the need for training in clinical anatomy to hold an important place in the development of tomorrow's clinicians.

Endogenous galanin potentiates spinal nociceptive processing following inflammation.

We have undertaken a series of experiments using galanin null mutant mice to better define the role of endogenous galanin in spinal excitability following inflammation and in response to centrally sensitizing stimuli. We have employed a behavioural paradigm, the formalin test, as a model of tonic nociception in both galanin knock-out (gal-/-) and wild-type (gal+/+) mice. In this model, we find that gal-/- mice are markedly hypo-responsive, especially in the second phase response. Additionally, we have examined the thermal hyperalgesia which develops following peripheral injection of carrageenan into the plantar surface of one hindpaw. In this inflammatory paradigm, thermal hyperalgesia is markedly attenuated in gal-/- mice. These behavioural findings suggest that endogenous galanin contributes to nociceptive processing. We have tested this hypothesis further by employing an electrophysiological measure of spinal excitability, the flexor withdrawal reflex in gal-/- and gal+/+ mice. We found no differences in acute reflex responses to single stimuli at C-fibre strength or in the time course and magnitude of wind-up induced by a short conditioning train between non-inflamed gal+/+ and gal-/- mice. However, the long-lasting post-conditioning enhancement of reflex excitability was only seen in gal+/+ mice. Moreover, following carrageenan inflammation, there was a marked increase in spinal nociceptive reflex excitability in the inflamed gal+/+ mice, but this enhanced excitability was absent in gal-/- animals. These findings illustrate that endogenous galanin is necessary for the full expression of central sensitization, and as such, plays a critical role in the development of hyperalgesia following peripheral tissue injury.