Percutaneous pulmonary valve replacement: autologous tissue-engineered valved stents.

AIMS: Percutaneous implantation has already been used clinically and is a great option for treating young patients. The use of autologous tissue-engineered valved stents might solve the problem of degeneration and limited durability of biological heart valves. METHODS AND RESULTS: Porcine pulmonary heart valves and small intestinal submucosa were obtained from a slaughterhouse. The intestinal submucosa was used to cover the inside of the porcine pulmonary valved stents. Endothelial cells (ECs) and autologous myofibroblasts (MFs) were used from carotid artery segments of juvenile sheep. After MF seeding, constructs were placed in a dynamic bioreactor system and cultured for 16 days. After additional EC seeding, tissue-engineered valved stents were percutaneously deployed into the annulus of the pulmonary valve (n = 9). Angiography was performed at implantation and 4-week follow-up. Constructs were analysed radiographically, by post-mortem examination, and microscopically. In all but one case, orthotopic positioning of the stents (n = 6) at the time of implantation and explantation was observed angiographically, macroscopically, and by computer tomography scan and demonstrated normal valve function (n = 7). Gross morphology confirmed excellent opening and closure characteristics of all leaflets after 4 weeks (n = 7). Strong expression of α-smooth muscle actin in neo-interstitial cells and of von Willebrand factor and PECAM-1 in ECs was revealed by immunocytochemistry. CONCLUSION: Good functioning and morphological characteristics were observed after percutaneous tissue-engineered valved stent implantation with autologous cells. This implantation of autologous tissue-engineered valved stents will become a valid future option in adolescents.

Prospective, randomized single-center trial to compare cryoplasty versus conventional angioplasty in the popliteal artery: midterm results of the COLD study.

PURPOSE: To evaluate safety and efficacy of cryoplasty versus conventional angioplasty for focal popliteal arterial occlusive disease. MATERIALS AND METHODS: Patients with focal atherosclerotic stenoses and occlusions of the popliteal artery were randomized to cryoplasty or conventional angioplasty as the initial treatment strategy. The primary objective was target lesion patency. The secondary endpoint was treatment success without the need for stents. Duplex ultrasonography was performed at 3, 6, 9, and 15 months. RESULTS: Eighty-six patients (mean age, 72 years; age range, 50-94 years) were enrolled in this study. Forty patients were randomized to cryoplasty and 46 to conventional angioplasty. Demographics, risk factors, clinical stage of disease, and lesion details were comparable. On intention-to-treat basis, initial success was 35% for cryoplasty versus 54% for conventional angioplasty (P = .02). The rate of grade C dissection was 35% after cryoplasty and 26% after conventional angioplasty (P = .4). Optional long-term percutaneous transluminal angioplasty (PTA) was performed in 58% of cryoplasty patients. The rate of stent placement for dissection and/or residual stenosis was 30% after cryoplasty (including long-term dilation) and 39% after conventional angioplasty (P = .34). The mean (+/-standard deviation) target lesion patency at 9 months was 79.3% +/- 7.5 for cryoplasty and 66.7% +/-8.1 for conventional angioplasty; however, the results are not significant (P = .14). CONCLUSIONS: Cryoplasty of the popliteal artery alone showed a lower anatomic success when compared with conventional angioplasty. Combined with optional long-term PTA, however, stent placement was not needed more often. There was a trend toward higher patency after cryoplasty, but differences were not statistically significant and results of long-term follow-up have to be awaited.

Low-profile primary stent placement for the treatment of focal calcified ulcerated stenosis in the infrarenal aorta.

PURPOSE: To analyze the immediate and midterm success of low-profile stent placement in calcified ulcerated lesions of the infrarenal aorta in patients with arterial occlusive disease. MATERIALS AND METHODS: In this prospective case series, 13 symptomatic patients (eight men, five women; mean age, 64.8 years +/- 12.1; age range, 44-84 years) with focal calcified ulcerated stenoses of the infrarenal aorta were treated with stent placement by using a low-profile technique in a radiology intervention center during a 4-year period. Clinical examinations and duplex ultrasonography were used to evaluate the stents? patency and clinical success. Kaplan-Meier graphs were calculated to analyze the freedom-of-symptom rate. RESULTS: The initial technical success rate was 92% (12 of 13 patients). Due to extended calcifications, a residual stenosis of 50%-60% remained in one patient. No peri-interventional complications occurred. The mean follow-up was 26 months (range, 5-53 months). During follow-up, one patient had a restenosis after 7 months and presented clinically with Fontaine stage IIb. Two patients had iliac and/or femoral stenoses, and both presented with Fontaine stage IIb. One patient's symptoms originated from the lumbar spine. Primary patency and primary clinical success rates were 85% and 69%, respectively. According to Kaplan-Meier tables, the freedom-from-symptom rates were 92%, 84%, 73%, and 63% at 0, 7, 12, and 21 months, respectively. CONCLUSIONS: Low-profile stent placement in calcified, ulcerated lesions of the infrarenal aorta is an effective and safe treatment for symptomatic stenoses in patients with arterial occlusive disease after a mean follow-up of 26 months.