Vascular Medicine

Propionyl-l-carnitine (PLC) may improve exercise performance in patients with peripheral artery disease, but results from clinical trials have been inconsistent. The safety and efficacy of PLC for treatment of claudication was evaluated by a systematic review and meta-analysis of clinical trials for which data were available through September 2010. Eighty-five studies were identified, of which 13 were randomized controlled trials. Owing to database availability for the six phase III studies carried out with PLC (1 g orally, twice daily), a patient-level meta-analysis was conducted as the primary analysis. Treadmill performance data from these six studies were harmonized to peak walking distance (PWD) on a 7% grade at a speed of 3 km/hour. PLC (n = 440) was associated with a net 16 meter improvement (95% CI, 8–20 meters) in PWD as compared with placebo (n = 427) in the primary analysis (p = 0.002). The effect of PLC was similar in subpopulations defined using clinical and demographic variables, with possible enhanced benefit in patients engaged in an exercise program or enrolled at study sites in Russia. The systematic review of the effect of PLCs on claudication identified seven additional randomized controlled trials for a total of 13 trials, which included 681 patients on placebo and 672 on PLC. This meta-analysis confirmed a 45 meter net improvement on PLC using a random-effects model. In conclusion, oral PLC is associated with a statistically significant increase in PWD in patients with claudication, which may be clinically relevant.

The aim of this study was to assess the association between peripheral arterial tonometry (PAT) and two more traditional measures of endothelial function – flow-mediated dilation (FMD) and its hyperemic stimulus, hyperemic peak velocity time integral (VTI). We related three vascular function measures (natural log transformed PAT, FMD, and VTI) from 304 patients (mean age 48.9 ± 12.5 years), including 105 with coronary artery disease (CAD). Using linear regression, we studied the relationships between lnPAT, FMD, and VTI, and compared differences in these parameters in those with and without CAD. Although FMD and lnPAT both had a correlation with VTI (Pearson’s r = 0.119, p = 0.039 and r = 0.167, p = 0.004, respectively), lnPAT had no correlation with FMD (r = −0.0471, p = 0.414). lnPAT was also lower in patients with CAD compared to controls (mean 0.51 ± 0.19 versus 0.65 ± 0.26, respectively, p < 0.0001). In multivariate analysis, VTI remained associated with lnPAT (standardized β = 0.1369, p = 0.04). Among this group of subjects with and without CAD, lnPAT was found to be unrelated to FMD but correlated with VTI. This would suggest that lnPAT is a measure of microvascular function. Although it is unrelated to FMD, lnPAT is decreased in patients with pre-existing cardiovascular disease. Further studies are required to determine if this can be used clinically as a tool for cardiac risk stratification and prediction of CAD.

Critical limb ischemia (CLI) is a major cause of limb loss and mortality among patients with advanced peripheral artery disease. Our objective was to evaluate the gender-specific differences in patient characteristics and clinical outcomes among patients with CLI. We performed a retrospective analysis of 97 women and 122 men presenting with CLI who underwent angiography from 2006 to 2010. Baseline demographics, procedural details, and lesion characteristics were assessed for each patient. Kaplan–Meier analysis was used to assess long-term patient and lesion-level outcomes. Cox proportional hazard modeling was used to evaluate the relationship between gender and major adverse cardiovascular events (MACE). Compared to men, women were less likely to have a history of coronary artery disease (39% vs 54%, p = 0.02) or diabetes (57% vs 70%, p = 0.05) but had similar baseline medical therapy. At angiography, women were more likely to have significant femoropopliteal (77% vs 67%, p = 0.02) and multi-level infrainguinal disease (63% vs 51%, p = 0.02). Women were also more likely to undergo multi-vessel percutaneous intervention (69% vs 55%, p = 0.05), but had similar rates of limb salvage after percutaneous intervention or surgical bypass (HR 0.94 [95% CI 0.45–1.94], p = 0.9). During follow-up, women had higher rates of subsequent major adverse cardiovascular events (HR 1.63 [95% CI 1.01–2.63], p = 0.04). In conclusion, women with CLI are more likely to present with femoropopliteal and multi-level infrainguinal disease. Despite similar rates of limb salvage, women with CLI have an increased rate of subsequent major adverse cardiovascular events.

Since the long-term patency of axillofemoral (AXF) grafts is inferior to aorto-bifemoral (ABF) grafts, limb salvage procedures are crucial in this group of patients. Emerging endovascular devices have helped in the successful restoration of flow for acute limb ischemia in both native arteries as well as bypass grafts. One such device, the Trellis™ thrombectomy system is being used more frequently in this setting. The device has previously been used in veins, native arteries, and rarely in aortofemoral grafts. We present its first successful use for the treatment of occluded AXF bypass graft. The use of this device helped to isolate the treatment zone in the occluded graft, which allowed the use of a lower dose of thrombolytics, less systemic release of thrombolytics, and less distal embolization. Resolution of extensive clot burden was achieved and, with subsequent stenting of the graft at the distal anastomotic site, arterial flow to the leg through the AXF graft was restored and a revision surgery was avoided.

Inferior vena cava (IVC) thrombosis remains under-recognised as it is often not pursued as a primary diagnosis. The aetiology of IVC thrombosis can be divided into congenital versus acquired, with all aetiological factors found among Virchow’s triad of stasis, injury and hypercoagulability. Signs and symptoms are related to aetiology and range from no symptoms to cardiovascular collapse. Painful lower limb swelling combined with lower back pain, pyrexia, dilatation of cutaneous abdominal wall veins and a concurrent rise in inflammatory markers are suggestive of IVC thrombosis. Following initial lower limb venous duplex, magnetic resonance imaging (MRI) is the optimal non-invasive imaging tool. Aetiology directs treatment, which ranges from anticoagulation and lower limb compression to open surgery, with endovascular therapies increasingly favoured. The objective of this review is to assess current literature on the aetiology, presentation, investigation, treatment, prognosis and other factors pertaining to IVC thrombosis.

Corrigendum to: The effects of vitamin D repletion on endothelial function and inflammation in patients with coronary artery disease. Seth I Sokol et al.

This article was published in VMJ 17(6) 394–404. DOI: 10.1177/1358863X12466709.

A co-author would like to include his middle initial in his name. It should read Amir H. Lebastchi.