Endovascular Exclusion of Popliteal Artery Aneurysms With Expanded Polytetrafluoroethylene Stent-Grafts: Early Results

There is increasing interest in using endovascular methods instead of surgical reconstruction to treat popliteal artery aneurysms. Exclusive use of the Viabahn stentgraft, a nitinol stent covered with expanded polytetrafluoroethylene, was assessed in the treatment of patients who presented with popliteal artery aneurysms in the absence of acute limb ischemia. Technical success, endoleaks, graft patency, freedom from amputation, and aneurysm sac flow and size changes were assessed by duplex ultrasound. From June 2004 to March 2006, 16 men (mean age, 76 years; range, 65-83) underwent endovascular exclusion of 23 popliteal artery aneurysms (mean diameter, 2.5 cm; range, 1.3-6.7 cm). Nine lesions had partial thrombus on preprocedural duplex imaging. Nineteen of the 23 limbs treated had at least 2-vessel tibial artery runoff. Procedures were performed under local anesthesia using ipsilateral percutaneous antegrade arterial access. All patients received 75 mg/day of clopidogrel afterward. Follow-up assessments included direct clinical examinations and duplex ultrasonography performed 1, 3, 6, and 12 months after the procedure. Primary patency and amputation-free survival were calculated using Kaplan-Meier analysis. Complete aneurysm exclusion (technical success) was achieved in all cases. During the mean follow-up of 7 months (range, 1-21 months), 22 of 23 treated limbs remained asymptomatic. One stent-graft thrombosis occurred 6 months after the procedure and was successfully treated with percutaneous mechanical thrombectomy, balloon angioplasty of a stent-graft stenosis, and insertion of an uncovered nitinol stent. No popliteal artery aneurysm sac size enlargements or endoleaks were detected. At 12 months, the treated limb mean anklebrachial index was 1.0 (range, 0.82-1.31) and the primary and secondary patency rates were 93% and 100%, respectively. Early results with Viabahn endovascular stent-graft exclusion of asymptomatic popliteal artery aneurysms are promising. Patient selection for endovascular repair depends on suitable popliteal artery anatomy, extent of aneurysmal degeneration, and quality of tibial arterial runoff.

Effects of muscle electrical stimulation on peak VO2 in cardiac transplant patients

Peak oxygen consumption (peak VO2) has become a critical component in the evaluation of heart transplant recipients (HTR). In these patients, peak VO2 remains low after cardiac transplantation mainly because of persisting peripheral limitations in the working muscles. Muscular electrical stimulation, on the other hand, has been shown to enhance the oxidative capacity of healthy muscle. It was the purpose of our investigation to study the effects of ES on the peak VO2 of HTR. Fourteen (11 males and 3 females) HTR (age: 57+/-7yr, mean +/- SD; height: 163+/-7 cm, weight: 70.5+/-8.6 kg) were selected as subjects and each of them was randomly assigned to one of two groups: (a) group EXP (n = 7), receiving electrical stimulation on both quadriceps muscles during a period of 8 weeks, and (b) group CONT (n = 7), not receiving electrical stimulation. Before (PRE) and after (POST) the aforementioned 8-week period, respectively, all the subjects performed a cardiopulmonary exercise test (ramp protocol) on a cycle ergometer for peak VO2 determination. PRE values of peak VO2 were similar in both groups (17.1+/-2.0 vs 16.9+/-3.8ml x kg(-1) x min(-1) in EXP and CONT, respectively). However, peak values of VO2 significantly increased in EXP (p < 0.05) after the period of electrical stimulation (POST peak VO2: 18.7+/-2.0ml x kg(-1)), whereas no change was observed in CONT (POST peak VO2: 16.2+/-3.2 ml x kg(-1) x min(-1)). In conclusion, electrical stimulation could therefore be used to improve the functional capacity of HTR, and might be included in the rehabilitation programs of this population group.