Factors predicting positive CT mesenteric angiography results in lower gastrointestinal haemorrhage prior to consideration of intra-arterial angio-embolisation.

INTRODUCTION: Lower gastrointestinal haemorrhage (LGIH) is a challenging phenomenon in a comorbid, elderly population. CT mesenteric angiography (CTMA) allows localisation of the site of haemorrhage, and provides a target for interventional techniques, but the intermittent nature of LGIH makes it challenging to reliably demonstrate extravasation. This study aimed to identify objective factors that may predict scan outcomes. METHODS: In this retrospective cohort study, all patients undergoing CTMA for LGIH at Monash Health from January 2011 to December 2019 (n = 854) were included. Baseline patient characteristics included age, bowel resection/endoscopic intervention within the past 14 days, known bowel malignancy, anticoagulant/antiplatelet use, duration of symptoms, vital signs, transfusion requirements in the past 24 h and investigation results (recent haemoglobin levels, platelet count, international normalised ratio and creatinine levels). Univariate analysis was performed, and significant factors were entered into a multivariate model. RESULTS: The final multivariate model was statistically significant (P < 0.001) and consisted of bowel resection/endoscopic intervention within the past 14 days (OR = 2.15), use of antiplatelet agents (OR = 2.03), blood transfusion requirement greater than 3 units per 24 h (OR = 1.79), systolic blood pressure less than 100 mmHg (OR = 1.56) and heart rate greater than 100 beats per minute (OR = 1.52). CONCLUSION: The factors identified above are objective, independently associated with positive scan outcomes, readily available to radiologists and are useful for more judicious patient selection.

Endovascular flow-diversion of visceral and renal artery aneurysms using dual-layer braided nitinol carotid stents.

BACKGROUND: Visceral and renal artery aneurysms (VRAAs) are uncommon but are associated with a high mortality rate in the event of rupture. Endovascular treatment is now first line in many centres, but preservation of arterial flow may be difficult in unfavourable anatomy including wide necked aneurysms, parent artery tortuosity and proximity to arterial bifurcations. Endovascular stenting, and in particular flow-diversion, is used in neurovascular intervention to treat intracranial aneurysms but is less often utilised in the treatment of VRAAs. The CASPER stent is a low profile dual-layer braided nitinol stent designed for carotid stenting with embolic protection and flow-diversion properties. We report the novel use of the CASPER stent for the treatment of VRAAs. We present a case series describing the treatment of six patients with VRAAs using the CASPER stent. RESULTS: Six patients with unruptured VRAAs were treated electively. There were three splenic artery aneurysms and three renalartery aneurysms. Aneurysms were treated with the CASPER stent, with or without loose aneurysm coil packing or liquid embolic depending on size and morphology. All stents were successfully deployed with no immediate or periprocedural complications. Four aneurysms completely occluded after serial imaging follow up with one case requiring repeat CASPER stenting for complete occlusion. In one patient a single aneurysm remained patent at last follow up, A single case was complicated by delated splenic infarction and surgical splenectomy. CONCLUSION: Preliminary experience with the CASPER stent suggests it is technically feasible and effective for use in the treatment of VRAAs.

Perforating arteries of the thigh: An anatomical and radiological study.

INTRODUCTION: We aimed to advance the understanding of the anatomy of the perforating branches of the profunda femoris artery to facilitate the avoidance of iatrogenic injury in surgery around the thigh and ensure safe percutaneous embolisation. METHODS: Dissection was carried out on seven cadavers, examining the relationship of the point of origin of the perforating branches of profunda femoris, relative to lines connecting palpable bony landmarks (lines A and B). These were compared with 16 computed tomography angiograms (CTA). Left to right variation within subjects and variation between the dissection and imaged group was examined. The anatomy of the two groups was then compared with that described in anatomical textbooks. RESULTS: The side to side variation in number of perforators was not significant in the dissection (P = 0.20) nor the CT group (P = 0.70). Similarly, the point of origin of the perforating vessels along lines A and B did not demonstrate any significant difference except for the fourth perforator along line B (P = 0.03). There was no significant difference in points of origin along line B between the dissection and CT groups for the first four perforators on the left (P = 0.51, P = 0.80, P = 0.66, P = 0.09 respectively) and right (P = 0.79, P = 0.45, P = 0.56, P = 0.11 respectively). The number and distribution of perforators were then compared with commonly used anatomical texts. CONCLUSION: As in other parts of the body, textbook descriptions of anatomical structures may not be reflected consistently in vivo. However, the perforating branches of the profunda femoris demonstrate a predictable topographical relationship to palpable bony landmarks.

Endoluminal thoracic aortic repair in the octogenarian and nonagenarian: the New Zealand experience.

INTRODUCTION: The aim of this study was to review the New Zealand-wide experience of thoracic endovascular aortic repair to determine effect of age on outcome. METHODS: This was an observational, retrospective analytic study comparing two age groups. The New Zealand Thoracic Aortic Stent (NZTAS) registry was reviewed for patient demographics, indications for repair, risk factors, technical success, complications, length of hospital stay and in-hospital mortality. RESULTS: The 264 patients were divided into two groups: <80 (Group I, n = 245) and >80 years on the day of the procedure (Group II, n = 19). Group II comprised 11 males and 8 females with a mean age (range) of 84 (80-90) years. Using the Society of Thoracic Surgeons's scoring system for risk factors, there was no significant difference between the groups. Technical success was 84% (n = 16) in Group II. The mean hospital stay in Group II was 20 (2-90) days and the in-hospital mortality 16% (n = 3). None of these outcomes was significantly different to those in the under 80 group (Group I). CONCLUSIONS: Data from NZTAS registry show outcomes and risk factors do not significantly differ between the two age groups.

Vertebral levels of key landmarks in the neck.

Vertebral levels of key landmarks in the neck are well documented in anatomy texts but are they accurate? This study aimed to investigate the vertebral levels of the hard palate, hyoid bone, thyroid cartilage, cricoid cartilage, and bifurcation of the common carotid artery (CCA) using computed tomography (CT). After excluding patients with distorting pathology, 52 CT scans of the neck from supine adults with a standardized head position (mean age 63 ± 17 years, range 30-94 years; 21 female) were available for analysis by dual consensus reporting. Only the vertebral level of the hard palate (C1) was consistent with contemporary descriptions. Other landmarks were located most frequently at the following vertebral levels: the center of the body of the hyoid bone at C4 (54% of cases); the superior limit of the laminae of the thyroid cartilage at C4 in women (60%) and C5 in men (52%) (P = 0.02); the inferior border of the cricoid cartilage in the midline anteriorly at C6 in women (37%) and C7 in men (47%) (P = 0.008); and the bifurcation of the left and right common carotid arteries at C3 (left 56%, right 62%). The bifurcation of the CCA was a mean of 1.6 ± 1.2 cm above the superior border of the thyroid laminae. Vertebral levels of key bony/cartilaginous structures in the neck differ from standard descriptions but in the absence of a standardized cervical axial plane have limited value and clinical utility.

A reappraisal of adult abdominal surface anatomy.

Descriptions of clinically important surface landmarks often vary between and within contemporary anatomical texts. The aim of this study was to investigate the surface anatomy of major abdominal vessels, kidneys, spleen, gastroesophageal junction, and duodenojejunal flexure in living adults using computed tomography (CT). After excluding patients with distorting space-occupying lesions, scoliosis, abnormal lordosis, and obvious visceromegaly, 108 abdominal CT scans of supine adults (mean age 60 years, range 18-97 years; 64 female) at end tidal inspiration were available for analysis by dual consensus reporting. Intra-observer agreement was assessed by repeat blind assessment of a random sample of scans. The vertebral level of the aortic bifurcation and almost all of its major branches, and the origin of the inferior vena cava were consistent with current descriptions. Important differences from contemporary descriptions of surface anatomy were as follows: the renal arteries were most commonly at the L1 vertebral level (left 55%, right 43%); the midpoint of the renal hila was most frequently at L2 (left 68%, right 40%); the 11th rib was a posterior relation of the left kidney in only 28% of scans; and the spleen was most frequently located between the 10th and 12th ribs (48%) with its long axis in line with the 11th rib (55%). Although the majority of vascular surface landmarks are consistent with standard descriptions, the surface anatomy of the kidneys, renal arteries, and spleen needs to be revised in accordance with observations using modern imaging techniques in vivo.

Anatomical planes: are we teaching accurate surface anatomy?

Anatomical planes used in clinical practice and teaching anatomy are largely derived from cadaver studies. Numerous inconsistencies in clinically important surface markings exist between and within anatomical reference texts. The aim of this study was to reassess the accuracy of common anatomical planes in vivo using computed tomographic (CT) imaging. CT scans of the trunk in supine adults at end tidal inspiration were analyzed by dual consensus reporting to determine the anatomy of five anatomical planes: sternal angle, transpyloric, subcostal, supracristal, and the plane of the pubic crest. Patients with kyphosis, scoliosis, or abnormal lordosis, distorting space-occupying lesions, or visceromegaly were excluded. Among 153 thoracic CT scans (mean age 63 years, 53% female), the sternal angle was most common at T4 (females) or T4/5 (males) vertebral level, and the tracheal bifurcation, aortic arch, and pulmonary trunk were most often below this plane. In 108 abdominal CT scans (mean age 60 years, 59% female), the subcostal and supracristal planes were most often at L2 (58%) and L4 (69%), respectively. In 52 thoracoabdominal CT scans (mean age 61 years, 56% female), the transpyloric plane was between lower L1 and upper L2 (75%); in this plane were the superior mesenteric artery (56%), formation of the portal vein (53%), tip of the ninth rib (60%), and the left renal hilum (54%), but the right renal hilum and gallbladder fundus were more often below. The surface anatomy of anatomical planes needs revising in the light of results from living subjects using modern imaging techniques.

A reappraisal of adult thoracic surface anatomy.

Accurate surface anatomy is essential for safe clinical practice. Numerous inconsistencies in clinically important surface markings exist between and within anatomical reference texts. The aim of this study was to investigate key thoracic surface anatomical landmarks in vivo using computed tomographic (CT) imaging. High-resolution thoracic CT scans from 153 supine adults (mean age 63, range 19-89 years; 53% female) taken at end tidal inspiration were analyzed by dual consensus reporting to determine the surface anatomy of the sternal angle, central veins, heart, lungs, and diaphragm. Patients with kyphosis/scoliosis, distorting space-occupying lesions, or visceromegaly were excluded. The position of the cardiac apex, formation of the brachiocephalic veins, and vertebral levels of the sternal angle, xiphisternal joint, and aortic hiatus were consistent with commonly accepted surface markings although there was a wide range of normal variation. In contrast, common surface markings were markedly inaccurate for the following: the position of the tracheal bifurcation, aortic arch, and azygos vein termination (below the plane of the sternal angle at T5-T6 vertebral level in most individuals); the superior vena cava/right atrial junction (most often behind the fourth costal cartilage); the lower border of the lung (adjacent to T12 vertebra posteriorly); and the level at which the inferior vena cava and esophagus traverse the diaphragm (T11 in most). Surface anatomy must be reappraised using modern imaging in vivo if it is to be evidence based and fit for purpose. The effects of gender, age, posture, respiration, build, and ethnicity also deserve greater emphasis.

Association of statin prescription with small abdominal aortic aneurysm progression.

BACKGROUND: Statins have been suggested to reduce expansion of abdominal aortic aneurysms (AAAs) independent of lipid-lowering effects. METHODS: We assessed the association of statin treatment and serum low-density lipoprotein (LDL) concentrations with small AAA expansion. Six hundred fifty-two patients undergoing surveillance of small AAAs were entered into the study from 5 vascular centers. In a subset, fasting lipids (n = 451) and other biomarkers (n = 216) were measured. The AAA diameter was followed by ultrasound surveillance for a median of 5 years. RESULTS: Three hundred forty-nine (54%) of the patients were prescribed statins. Adjusting for other risk factors, statin prescription was not associated with AAA growth (odds ratio [OR] 1.23, 95% CI 0.86-1.76). Above-median AAA growth was positively associated with initial diameter (OR 1.78 per 4.35-mm-larger initial aortic diameter, 95% CI 1.49-2.14) and negatively associated with diabetes (OR 0.37, 95% CI 0.22-0.62). Above-median serum LDL concentration was not associated with AAA growth. Patients receiving statins had lower serum C-reactive protein concentrations but similar matrix metalloproteinase-9 and interleukin-6 concentrations to those not prescribed these medications. CONCLUSIONS: We found no association between statin prescription or LDL concentration with AAA expansion. The results do not support the findings of smaller studies and suggest that statins may have no benefit in reducing AAA progression.

Endovascular repair of chronic mesenteric occlusive disease: the role of duplex surveillance.

BACKGROUND: Chronic occlusive mesenteric ischaemia can be treated surgically or endovascularly. Endovascular techniques as elsewhere in the vascular tree are limited by restenosis. The aim of this study was to determine if duplex ultrasound proven restenosis correlates with recurrence of symptoms. METHODS: Our study looks at successful percutaneous revascularization of the mesenteric circulation associated proven restenosis using colour Doppler ultrasound and the relation to recrudescence of symptoms or weight loss. A retrospective review of five patients treated endovascularly at our institution for mesenteric angina secondary to visceral artery stenosis was carried out. RESULTS: Technical success was achieved in four out of the five patients in our study. One patient had a procedure complicated by thrombus in the coeliac axis and superior mesenteric artery (SMA) stents, subsequently showed SMA occlusion and 90% stenosis of the CA and inferior mesenteric artery and required an aorto-mesenteric graft. Three of the four patients with a technically successful procedure had significant (>70%) restenosis of the SMA. All three, including one patient with both SMA restenosis and chronic inferior mesenteric artery occlusion, remain asymptomatic and have maintained their postprocedural weight gain. CONCLUSION: Although ultrasound is a convenient, non-invasive tool for follow up of endovascular treatment of mesenteric stenosis, its use is unclear as in our study restenosis did not correlate with recrudescence of symptoms.

Comparison of duplex ultrasound with digital subtraction angiography in the assessment of infra-inguinal autologous vein bypass grafts.

BACKGROUND: Postoperative surveillance of infra-inguinal vein grafts has arisen because of the high incidence of vein graft stenoses, which frequently progress to vein graft occlusion. The use of duplex ultrasound as the primary imaging method for graft surveillance is well established. This study aims to compare the accuracy of duplex ultrasound with the reference standard of digital subtraction angiography in the assessment of infra-inguinal vein grafts. METHODS: Sixty patients underwent routine postoperative duplex ultrasound as part of the local graft surveillance programme. Angiography was subsequently carried out on 18 grafts. Each lower limb arterial tree was divided into three segments (native arteries proximal to the graft, the graft itself and native arteries distal to the graft) resulting in a total of 42 comparisons. Degree of diameter stenosis on ultrasound was compared with angiography findings to determine concordance. Agreement was also expressed as a kappa value. RESULTS: Overall accuracy of duplex ultrasound was 88% (37/42). A kappa value of 0.80 indicates good agreement. In three of the five discordant cases, ultrasound correctly identified a stenosis, but overestimated the degree of stenosis compared with angiography. In each of the remaining two discordant cases, ultrasound identified a focal stenosis that was not apparent on angiography. In both cases, the area of duplex described abnormality responded to balloon angioplasty. CONCLUSION: Duplex ultrasound as part of the local vein graft surveillance programme is a reliable and accurate method in the detection of failing grafts and in some instances may be more sensitive.

Informed consent for vascular intervention.

AIM: To audit documentation of the process of informed consent in patients undergoing vascular surgical and radiological procedures. METHOD: A retrospective audit of randomly selected elective vascular radiological and surgical admissions was undertaken at Christchurch Hospital (Christchurch, New Zealand) to assess documented evidence of the consent process. Clinic letters, handwritten entries in patient notes, and consent forms were scrutinised and data collated on which medical practitioners took consent, what details of the consent process were documented, and what additional information was made available to patients. RESULTS: 100 sets of notes were reviewed (surgical n=51, radiological n=49). For patients undergoing vascular surgery, the consent form was signed by a consultant in 2 (4%) sets of notes compared to 46 (94%) for patients undergoing vascular radiological intervention (p<0.001). All radiology consent forms were signed on the day of the procedure whereas 43 (84%) of surgical consent forms were signed before the day of surgery (p<0.01). Documentation that risks had been discussed with the patient was present in 44 (86%) sets of surgical notes compared to 20 (41%) radiology notes (p<0.001). Additional information (e.g. College of Surgeons' information leaflets) was supplied to 6 (12%) surgical patients and none of the patients undergoing radiological intervention (p<0.05). CONCLUSIONS: In our centre, documentation of the process of informed consent compares favourably with the published literature. This study demonstrates significant differences in documentation between surgery and radiology.

Spectral Doppler characterization of endoleaks following endoluminal abdominal aortic aneurysm repair.

BACKGROUND: Colour Doppler ultrasound of endoluminal abdominal aortic aneurysm repair is becoming an established imaging technique in identifying endoleak. Management and treatment of endoleak is determined in part by the exact nature of the endoleak, namely its type and whether it has single or multiple vessel inflow and outflow. To date, spectral Doppler waveform analysis has provided some information about the propensity for spontaneous seal of isolated type II endoleaks, rather than assisting in their classification. METHODS: We present a collection of three case reports outlining the directionality/phasicity of the Doppler waveform profile associated with endoleaks whose type and subtype (uni- /or multi-conduital) were angiographically determined. RESULTS: In all three cases uniconduital type II endoleak demonstrated a to-and-fro waveform on Doppler ultrasound imaging. CONCLUSIONS: To-and-fro Doppler waveforms may be associated with uniconduital type II endoleaks. If upon investigation of further cases this is found to be the case, this waveform classification may facilitate determination of the subtype (uni- or multi-conduital) of endoleak, thus identifying those cases which may be more amenable to percutaneous repair.