Frank J. Rivera

Stenting of the iliac arteries with the palmaz stent: Experience from a multicenter trial

Balloon-expandable, intraluminal stenting of the iliac arteries with the Palmaz stent was the subject of a multicenter study for 4 years. A total of 486 patients underwent 587 procedures. Four hundred and five patients had unilateral and 81 had bilateral iliac stent placements. Follow-up ranged from 1 to 48 months (mean 13.3±11 months). Sustained clinical benefit of the treated patients was obtained in 90.9% at 1 year, 84.1% at 2 years, and 68.6% at 43 months. Angiographic patency rate was 92%. Diabetes mellitus and poor runoff had significant negative influence on the clinical outcome. The 10% incidence of procedural complications was not altered by operator experience.

Mesenteric angioplasty in the treatment of chronic intestinal ischemia

PURPOSE This study was undertaken to determine the safety and efficacy of percutaneous transluminal angioplasty (PTA) in the treatment of chronic mesenteric ischemia (CMI) in very high-risk surgical patients. METHODS Twenty-four focal mesenteric stenoses treated from 1984 to 1994 by PTA in 19 patients with CMI were reviewed. All 19 patients were considered poor surgical candidates. Seventeen patients had classic symptoms of CMI, and two patients had atypical abdominal complaints. Vessels dilated included the superior mesenteric artery (18), celiac artery (3), inferior mesenteric artery (1), aorta-superior mesenteric artery vein graft (1), and aorta-splenic artery vein graft (1). Complete follow-up was possible in all patients, with the exception of one patient who had no symptoms when last seen 17 months after the procedure. RESULTS PTA was technically successful in 18 of 19 patients (95%) and 23 of 24 stenoses (96%). The lone technical failure resulted in superior mesenteric artery dissection with thrombosis and bowel infarction; the patient died despite emergent laparotomy and revascularization (mortality rate, 5%). Complete symptomatic relief was attained in 15 patients (79%), with follow-up showing continued relief of symptoms for a mean of 39 months (range, 4 to 101 months). Partial symptomatic relief was attained in three patients. Recurrent symptoms developed in three patients (20%) at a mean interval of 28 months (range, 9 to 43 months). Repeat PTA performed in two patients provided good technical results and relief from clinical symptoms. One patient had a symptomatic axillary sheath hematoma that required surgical decompression. CONCLUSIONS Mesenteric PTA is a valuable treatment option in patients who have CMI and are considered very high operative risks. The initial technical success rate is excellent, with the majority of patients having complete symptomatic improvement and continued relief of symptoms at short-term follow-up.

Aortic bifurcation stenosis: treatment with intravascular stents.

Balloon-expandable intravascular stents were employed to correct atherosclerotic stenosis of the aortic bifurcation. The devices were placed in the proximal iliac arteries with the cephalic end of the stents contacting in the midline. This arrangement provided an adequate lumen for the distal portion of the aortic wall and the proximal iliac arteries. Six of seven patients who received this form of treatment had hemodynamic and clinical improvement of their vascular insufficiency at an average follow-up of 1 year.

Influence of Anatomic Distribution of Atherosclerosis on the Outcome of Revascularization with Iliac Stent Placement

PURPOSE To determine the influence of clinical and angiographic variables, including the anatomic disease pattern, on the outcome of iliac stent placement. PATIENTS AND METHODS The 455 patients of the study population were divided in three groups according to the anatomic distribution of their peripheral atherosclerosis lesions. Pattern type 1 (focal aortoiliac and/or common iliac lesion) included 180 patients (39.6%), type 2 (external iliac lesion) comprised 58 patients (12.8%), and type 3 (multilevel lesions) included 217 patients (47.7%). RESULTS Complete relief of symptoms immediately after revascularization was observed in 88.3% and 85.4% of patients with pattern type 1 and 2, respectively, compared to 60.1% with type 3 (P < .05). The persistence of clinical benefit at 36-month follow-up was 91.6%, 97.9%, and 60.8% in disease patterns 1, 2, and 3, respectively. The overall 1-year mortality rate was 3% with type 1 lesions, 5.7% with type 2, and 9.7% with type 3. On multivariate logistic regression, the presence of a disease pattern type 3 was the most powerful indicator (P < .001) of early unsatisfactory clinical outcome in iliac stent placement. Unexpectedly, female gender was predictive of unsatisfactory clinical outcome (P < .01) and higher periprocedural complications (P < .001) following iliac stent revascularization. CONCLUSIONS Pattern type classification helps identify patients at higher risk for cardiovascular morbidity and mortality. Ideal candidates for iliac stent placement are patients with pattern type 1 or 2 disease.

Use of Stents Covered with Polytetrafluoroethylene in Experimental Abdominal Aortic Aneurysm

PURPOSE To establish the effectiveness of covered stents in the treatment of aortic aneurysms, to investigate the histopathologic healing patterns of the device, and to determine the long-term endurance and integrity of modified polytetrafluoroethylene (PTFE). MATERIALS AND METHODS Experimental aneurysms were created in dogs by enlarging the aortic lumen with a patch of abdominal fascia. After 5 months, eight animals underwent an endoluminal bypass. The bypass device consisted of a 6-cm-long stent covered with thin PTFE. After surgery, the animals were killed at 3, 6, and 12 months in groups of three, three, and two, respectively. Specimens were processed for luminal surface studies and cross-sectional histologic study. Explanted PTFE material was analyzed for its physical characteristics and performance and was compared with retained control samples. RESULTS Before the animals were killed, aortography showed patent bypass conduits in all animals, although two of eight had leaks into the aneurysmal sac. Endothelialized neointima largely covered the luminal surface of the PTFE stent. The percentage of prosthetic surface covered by tissue did not change from 3 months to 1 year. Physical testing of the explanted PTFE material showed no structural deterioration and no change in the internodal distance. Thickness and axial tensile strength varied 12% and 17% from controls, respectively. CONCLUSION Thin-walled PTFE seems to have physicochemical characteristics that make this material adequate for endovascular use. Though limited, this study supports the establishment of preliminary clinical evaluation of metallic stents combined with PTFE for the treatment of abdominal aortic aneurysm.

Percutaneous Aortic Stent Placement for Life Threatening Aortic Rupture Due to Metastatic Germ Cell Tumor

Patients with testicular carcinoma frequently present with advanced disease and symptoms resulting from metastatic lesions. We report an unusual case of successful emergency management of a massive rupturing aortic pseudoaneurysm midway through systemic chemotherapy for stage III germ cell tumor by percutaneous trans-luminal placement of an aortic bypass stent-graft. Unstable hemorrhage was controlled, allowing our patient to complete chemotherapy and undergo elective retroperitoneal lymph node dissection with resection of the pseudoaneurysm and residual disease after normalization of tumor markers. Final pathological evaluation revealed only fibrosis in the resected tissue. Followup angiography demonstrated a patent stent-graft and the patient was without evidence of disease 1 year after retroperitoneal lymph node dissection.