Five-year outcomes following a randomized trial of femorofemoral and femoropopliteal bypass grafting with heparin-bonded or standard polytetrafluoroethylene grafts.

BACKGROUND: Cohort studies suggest superior long-term patency of luminal heparin-bonded polytetrafluoroethylene (Hb-PTFE) bypass grafts compared with standard PTFE grafts. The aim of this study was to compare the outcomes of Hb-PTFE grafts with those of standard PTFE grafts 5 years after a randomized trial. METHODS: Patients with intermittent claudication or critical limb ischaemia requiring femorofemoral or femoropopliteal bypass grafting were randomized in a clinical trial of Hb-PTFE versus standard PTFE in 11 Scandinavian centres between 2005 and 2009. Patients were followed up for 5 years with clinical assessment and surveillance Duplex ultrasound imaging. The primary endpoint of this study was primary patency. Secondary endpoints included major amputation and mortality. RESULTS: Overall, 569 patients were enrolled in the randomized trial. Some 552 had follow-up data available for analysis of the primary outcome. Use of Hb-PTFE significantly improved patency by 37 per cent at 2 years, but 5 years after randomization there was no difference in primary patency (adjusted hazard ratio (HR) 0·95, 95 per cent c.i. 0·71 to 1·28; P = 0·748). In patients with critical limb ischaemia the use of Hb-PTFE reduced the 5-year risk of loss of primary patency by 37 per cent (HR 0·63, 0·40 to 0·99; P = 0·049). CONCLUSION: In this study there was no difference in primary graft patency between Hb-PTFE and standard PTFE grafts. Patients receiving Hb-PTFE grafts for critical limb ischaemia were more likely to have a patent graft at 5 years than those with standard PTFE grafts.

Mural thrombus and the progression of abdominal aortic aneurysms: a large population-based prospective cohort study.

OBJECTIVE: To investigate whether the relative size of intraluminal thrombus (ILT) in abdominal aortic aneurysms (AAAs) is associated with AAA growth. METHODS: This large observational study was based on a randomised population-based screening trial. Six hundred and fifteen AAAs were diagnosed in men aged 65-74 years. The relative cross-sectional area covered by the mural thrombus was estimated by a semiautomatic method using ultrasound equipment to measure the area of the ellipses, and adapting the inner ellipse (IA) to the luminal border of the thrombus and the outer ellipse to the area inside the media border (OA). The relative thrombus area was then calculated as ((OA-IA)/OU) × 100%. Four hundred and sixteen of the patients with AAA were eligible for analysis. RESULTS: The mean size of the AAA was 40.6 mm, and the mean observation time was 1.78 years. In the group with AAAs measuring 30-34 mm, 42% had ILT, with a mean relative size of 12% of the outer area. In the group with AAAs measuring >64 mm, the presence of ILT increased to 100%, with a mean relative size of 70% of the outer area. Univariate analysis showed relative ILT size, aortic diameter, smoking history, and diastolic blood pressure were significantly positively associated with growth rate, while the presence of diabetes mellitus was significantly negatively associated with growth rate. The relative ILT size remained significantly positively associated with the growth rate after a multivariate linear regression adjusting for potential confounders. CONCLUSION: These findings suggest that ILT may play a part in the progression of AAAs.

The cardiac cycle is a major contributor to variability in size measurements of abdominal aortic aneurysms by ultrasound.

AIM: The objective of the study was to evaluate the impact of the cardiac cycle on ultrasound measurements of abdominal aortic aneurysm (AAA) diameters. METHODS: In total, 603 AAAs detected by screening were investigated with respect to the maximal systolic and diastolic anterior-posterior aortic diameters during the cardiac cycle using recorded ultrasound video sequences. RESULTS: On average, the systolic AAA diameter was 41.60 mm, and the diastolic AAA diameter was 39.63 mm with a paired mean difference at 1.94 mm (p < 0.0001). No association between aneurysmal size and difference in systolic and diastolic size was noted. The mean difference and variability between two observers, one measured during peak-systole and the other measured during end-diastole, was 2.65 and 2.21 mm, respectively, as compared with 0.86 and 1.52 mm, respectively, when both were measured during the peak of systole. The intraobserver variability was 0.94 during systole, 1.18 during diastole and 1.94 mm when systole and diastole measurements were combined. CONCLUSION: The lack of a standardised measurement of the AAA diameter during the cardiac cycle is a potential major contributor to the variability in ultrasonography measurements.