Stent Deployment Pressure Defines the Stent/Vessel Wall Relationship and has Important Implications for Early and Late Outcome.

OBJECTIVE: This study evaluates the effect of stent deployment pressure on stent deployment, coronary vessel injury, subacute reclosure and foreign body reaction in a porcine coronary model. METHODS: Stainless steel coil stents were deployed in the right coronary artery of 30 pigs either using a deployment pressure of 4 atm (group I), 8 atm (group II), or 14 atm (group III). Serial quantitative angiographic studies together with morphometric analysis of the stented vessels were performed. RESULTS: Three pigs died within 48 hours due to subacute thrombosis (group I: n = 1, group II: n = 0, group III: n = 2). Another 4 stents were found occluded at day 7 (group I: n = 3, group II: n = 0, group III: n = 1). Imperfect stent alignment was found in 8 coronary arteries (group I: n = 7, group II: n = 1, group III: n = 0). Deep protrusion of stent filaments was found in 7 coronary arteries (group I: n = 0, group II: n = 1, group III: n = 6). Area stenosis at 6 weeks of the patent vessels was as follows: 75.7 +/- 15.2% in group I, 31.8 +/- 12.3% in group II, and 66.9 +/- 21.4% in group III, p < 0.001). CONCLUSION: In a porcine coronary model, stent deployment pressure resulting in an optimal alignment and a minimal coronary vessel injury leads to minimal neointimal hyperplasia.

Clinical and Angiographic Experience with Coronary Stenting Using Freedomª Stent.

The immediate safety and efficacy and the 6 month clinical and angiographic follow-up of a new fish-scale designed coronary coil stainless steel stent (Freedomª) was assessed by a prospective study. During 1995, 169 patients were treated on 177 vessels using 233 Freedom stents. Procedural indication for stenting was a bail-out situation in 79 vessels, a suboptimal angioplasty result in 62 vessels and a third restenosis after PTCA in 36 vessels. Procedural success was achieved in 170 vessels (96%); in 162 patients (96%). Subacute thrombotic occlusion occurred in one patient (0.6%). Acute myocardial infarction occurred in 7 patients (4.1%). Bleeding complications, necessitating blood transfusion occurred in 6 patients (3.6%). There were two non-stent related deaths. Recurrence of stent-related angina pectoris and/or a positive stress test occurred in 10 pts (6.4%). Elective control angiography at 6 months was performed in the first 85 patients. Stent restenosis of ³ 50% diameter stenosis was found in 14 patients (16.5%).