Ian M. Penn

A Randomized Comparison of Coronary-Stent Placement and Balloon Angioplasty in the Treatment of Coronary Artery Disease

BACKGROUND Coronary-stent placement is a new technique in which a balloon-expandable, stainless-steel, slotted tube is implanted at the site of a coronary stenosis. The purpose of this study was to compare the effects of stent placement and standard balloon angioplasty on angiographically detected restenosis and clinical outcomes. METHODS We randomly assigned 410 patients with symptomatic coronary disease to elective placement of a Palmaz-Schatz stent or to standard balloon angioplasty. Coronary angiography was performed at base line, immediately after the procedure, and six months later. RESULTS The patients who underwent stenting had a higher rate of procedural success than those who underwent standard balloon angioplasty (96.1 percent vs. 89.6 percent, P = 0.011), a larger immediate increase in the diameter of the lumen (1.72 +/- 0.46 vs. 1.23 +/- 0.48 mm, P < 0.001), and a larger luminal diameter immediately after the procedure (2.49 +/- 0.43 vs. 1.99 +/- 0.47 mm, P < 0.001). At six months, the patients with stented lesions continued to have a larger luminal diameter (1.74 +/- 0.60 vs. 1.56 +/- 0.65 mm, P = 0.007) and a lower rate of restenosis (31.6 percent vs. 42.1 percent, P = 0.046) than those treated with balloon angioplasty. There were no coronary events (death; myocardial infarction; coronary-artery bypass surgery; vessel closure, including stent thrombosis; or repeated angioplasty) in 80.5 percent of the patients in the stent group and 76.2 percent of those in the angioplasty group (P = 0.16). Revascularization of the original target lesion because of recurrent myocardial ischemia was performed less frequently in the stent group than in the angioplasty group (10.2 percent vs. 15.4 percent, P = 0.06). CONCLUSIONS In selected patients, placement of an intracoronary stent, as compared with balloon angioplasty, results in an improved rate of procedural success, a lower rate of angiographically detected restenosis, a similar rate of clinical events after six months, and a less frequent need for revascularization of the original coronary lesion.

Efficacy of Coronary Stenting Versus Balloon Angioplasty in Small Coronary Arteries

OBJECTIVES The goal of this study was to compare the efficacy of elective stent implantation and balloon angioplasty for new lesions in small coronary arteries. BACKGROUND Palmaz-Schatz stents have been designed and approved by the Food and Drug Administration for use in coronary arteries with diameters > or = 3.0 mm. The efficacy of elective stent placement in smaller vessels has not been determined. METHODS By quantitative coronary angiography, 331 patients in the Stent Restenosis Study (STRESS) I-II were determined to have a reference vessel < 3.0 mm in diameter. Of these, 163 patients were randomly assigned to stenting (mean diameter 2.69 +/- 0.21 mm), and 168 patients were assigned to angioplasty (mean diameter 2.64 +/- 0.24 mm). The primary end point was restenosis, defined as > or = 50% diameter stenosis at 6-month follow-up angiography. Clinical event rates at 1 year were assessed. RESULTS Baseline clinical and angiographic characteristics were similar in the two groups. Procedural success was achieved in 100% of patients assigned to stenting and in 92% of patients assigned to angioplasty (p < 0.001). Abrupt closure within 30 days occurred in 3.6% of patients in both groups. Compared with angioplasty, stenting conferred a significantly larger postprocedural lumen diameter (2.26 vs. 1.80 mm, p < 0.001) and a larger lumen at 6 months (1.54 vs. 1.27 mm, p < 0.001). Restenosis (> or = 50% diameter stenosis at follow-up) occurred in 34% of patients assigned to stenting and in 55% of patients assigned to angioplasty (p < 0.001). At 1 year, event-free survival was achieved in 78% of the stent group and in 67% of the angioplasty group (p = 0.019). CONCLUSIONS These findings suggest that elective stent placement provides superior angiographic and clinical outcomes than balloon angioplasty in vessels slightly smaller than 3 mm.

Improved Clinical Outcome after Widespread Use of Coronary-Artery Stenting in Canada

Background The introduction and refinement of coronary-artery stenting dramatically changed the practice of percutaneous coronary revascularization in the mid-1990s. We analyzed one-year follow-up data for all percutaneous coronary interventions performed in a large, unselected population in Canada to determine whether the use of coronary stenting has been associated with improved outcomes. Methods Prospectively collected data on all percutaneous coronary interventions performed on residents of British Columbia, Canada, between April 1994 and June 1997 were linked to province-wide health care data bases to provide the date of the following end points: subsequent target-vessel revascularization, myocardial infarction, and death. Base-line characteristics and procedural variables were identified and Kaplan–Meier survival curves were generated for 9594 procedures divided into seven groups, one for each sequential half-year period. Results The overall burden of coexisting illnesses remained stable throughout ...

Thrombosis and restenosis after stenting in failed angioplasty: Comparison with elective stenting

The results of Palmaz-Schatz stent implantation in failed angioplasty in 60 consecutive patients were compared with those of elective stent implantation in 100 consecutive patients. Stent implantation was successful in all of the failed group and in 99% of the elective. Stent thrombosis occurred in 16.7% of the failed group and 2% of the elective (p = 0.001). In the failed angioplasty group, stent thrombosis was associated with a greater frequency of preprocedure complex morphology (40% vs 12% in the nonthrombosis group, p = 0.05), persistent uncovered dissection after stenting (60% vs 14%, p = 0.004), and greater residual stenosis (39.9% +/- 25.3% vs 24.9% +/- 13.08%, p = 0.008) after stenting. Vessel patency was reestablished by angioplasty in 5 of 10 with stent thrombosis. Of these 5 patients, however, 2 suffered repeat stent thrombosis; 1 died suddenly four months later; and restenosis occurred in the remaining 2. Follow-up angiography was performed in 98% of the elective group at 6.3 +/- 2.6 months and 96% of the failed angioplasty group at 6.4 +/- 2.1 months. Restenosis (> or = 50% stenosis) occurred in 32% of the elective group and 50% of the failed angioplasty group (p = 0.041). Multiple logistic regression analysis identified multiple stent implantation (F = 6.75, p = 0.01) and triple-vessel disease (F = 3.46, p = 0.06) as independent positive predictors of restenosis. In conclusion, stent implantation in cases of failed angioplasty could be performed with a success similar to that of elective stent implantation but was associated with a greater frequency of stent thrombosis and restenosis.

First international new intravascular rigid-flex endovascular stent study (FINESS): Clinical and angiographic results after elective and urgent stent implantation

OBJECTIVES The purpose of this study was to determine the feasibility, safety and efficacy of elective and urgent deployment of the new intravascular rigid-flex (NIR) stent in patients with coronary artery disease. BACKGROUND Stent implantation has been shown to be effective in the treatment of focal, new coronary stenoses and in restoring coronary flow after coronary dissection and abrupt vessel closure. However, currently available stents either lack flexibility, hindering navigation through tortuous arteries, or lack axial strength, resulting in suboptimal scaffolding of the vessel. The unique transforming multicellular design of the NIR stent appears to provide both longitudinal flexibility and radial strength. METHODS NIR stent implantation was attempted in 255 patients (341 lesions) enrolled prospectively in a multicenter international registry from December 1995 through March 1996. Nine-, 16- and 32-mm long NIR stents were manually crimped onto coronary balloons and deployed in native coronary (94%) and saphenous vein graft (6%) lesions. Seventy-four percent of patients underwent elective stenting for primary or restenotic lesions, 21% for a suboptimal angioplasty result and 5% for threatened or abrupt vessel closure. Fifty-two percent of patients presented with unstable angina, 48% had a previous myocardial infarction, and 45% had multivessel disease. Coronary lesions were frequently complex, occurring in relatively small arteries (mean [+/-SD] reference diameter 2.8 +/- 0.6 mm). Patients were followed up for 6 months for the occurrence of major adverse cardiovascular events. RESULTS Stent deployment was accomplished in 98% of lesions. Mean minimal lumen diameter increased by 1.51 +/- 0.51 mm (from 1.09 +/- 0.43 mm before to 2.60 +/- 0.50 mm after the procedure). Mean percent diameter stenosis decreased from 61 +/- 13% before to 17 +/- 7% after intervention. A successful interventional procedure with < 50% diameter stenosis of all treatment site lesions and no major adverse cardiac events within 30 days occurred in 95% of patients. Event-free survival at 6 months was 82%. Ninety-four percent of surviving patients were either asymptomatic or had mild stable angina at 6 month follow-up. CONCLUSIONS Despite unfavorable clinical and angiographic characteristics of the majority of patients enrolled, the acute angiographic results and early clinical outcome after NIR stent deployment were very promising. A prospective, randomized trial comparing the NIR stent with other currently available stents appears warranted.

Safety, success, and restenosis after elective coronary implantation of the Palmaz-Schatz stent in 100 patients at a single center

We report the immediate safety, efficacy, and 6-month angiographic follow-up after elective implantation of the Palmaz-Schatz stent (Johnson & Johnson Interventional Systems, Warren, N.J.) in the first 100 consecutive patients at a single center. Patients with suitable cardiac anatomy and no contraindications to anticoagulation were prospectively entered into the study. One hundred two stents were successfully implanted in 99 patients. The mean diameter stenosis was 70% +/- 11% before implantation and was reduced to 20% +/- 11% after stent implantation. There were no deaths, Q-wave myocardial infarcts, urgent bypass operations, or strokes during the procedure or follow-up period. Stent thrombosis occurred in two patients; in both vessel patency was successfully accomplished by balloon angioplasty. There were three gastrointestinal hemorrhages, two of which required transfusion. Angiographic follow-up was performed in 98% of patients at 6.3 +/- 2.6 months after the procedure. Restenosis (> or = 50% stenosis within or immediately adjacent to the stent) occurred in 32%. Stent restenosis was associated with male sex (36% vs 7% for female subjects; p = 0.03) and stent implantation in a restenosis lesion (47% vs 25% for de novo lesions; p = 0.03); it was inversely associated with current cigarette smoking (0% vs 36% for nonsmokers; p = 0.02). In conclusion, the Palmaz-Schatz stent can be electively implanted with high success and low complication rates. The restenosis rate appears to be similar to that of balloon angioplasty.

A novel endovascular clip system for the treatment of intracranial aneurysms: technology, concept, and initial experimental results. Laboratory investigation.

OBJECT The authors describe a novel device for the endovascular treatment of intracranial aneurysms, the endovascular clip system (eCLIPs). Descriptions of the device and its delivery system as well as the results of flow model tests and the treatment of experimental aneurysms are provided. METHODS The eCLIPs comprises a flexible hybrid implantable device (an anchor and a covered leaf) and a balloon catheter delivery system, designed to be positioned and activated in the parent vessel in such a way that the covered portion will abut the aneurysm neck. The eCLIPs was subjected to testing in glass, elastomeric, and cadaveric flow models to determine its navigability, orientation, and activation compared with commercially available stents. In a second experiment, 8 carotid artery sidewall aneurysms in swine were treated using eCLIPs. The degree of occlusion was observed on angiography immediately following and 30 days after device activation, and a histological analysis was performed at 30 days. RESULTS The device could navigate tortuous glass models and human cadaveric vessels. Compared with commercially available stents, the eCLIPs performed well. It could be navigated, oriented, and activated easily and reliably. With regard to the 8 porcine experimental aneurysms, immediate postactivation angiograms confirmed complete occlusion of 4 lesions and near occlusion of the other 4. Angiographic follow-up at 30 days postactivation showed occlusion of all 8 aneurysms and patency of all parent vessels. Histopathological analysis revealed aneurysm healing, with smooth-muscle cells growing across the lesion neck to allow reendothelialization. CONCLUSIONS Aneurysm occlusion with a single extrasaccular endovascular device has potential advantages. The authors believe that eCLIPs may prove to be a useful tool in the endovascular treatment of cerebral aneurysms. The system should reduce risks associated with coiling, procedure time, costs, and radiation exposure. The device satisfactorily occluded 8 experimental sidewall aneurysms. The observed healing pattern is similar to that seen after microsurgical clipping.

Early and intermediate term clinical outcome after multiple coronary stenting

Objective To examine the immediate and intermediate term clinical outcome of multiple coronary stenting. Design Consecutive patients were prospectively entered on a dedicated database. Follow up information was obtained from outpatient and telephone interviews with patients and family physicians. Setting A tertiary referral centre. Patients 140 consecutive patients underwent multiple coronary stenting between April 1994 and November 1996. Most patients had unstable coronary syndromes. Main outcome measures Death, cerebrovascular accidents, myocardial infarction (MI), coronary artery bypass surgery (CABG), and repeat angioplasty (PTCA). Results The angiographic success rate was 100% and the clinical procedural success rate 93%. The mean (SD) follow up was 11.9 (7.2) months (range 2–32). The mean (SD) number of stents per patient was 2.4 (0.7). The mean (SD) number of lesions treated per patient was 1.4 (0.6). There were four in-hospital deaths (2.9%) and five patients (3.6%) had an MI before hospital discharge. All in-hospital deaths occurred in patients presenting with an acute MI and cardiogenic shock. Three patients (2.2%) had a late MI. One patient with stent thrombosis underwent emergency CABG. Three patients (2.2%) underwent late CABG. Eight patients (5.7%) had a repeat PTCA. Eighty three patients (61.5%) were asymptomatic at follow up and 121 (86.4%) were free from major clinical events. Conclusion In an era of increased operator experience, high pressure stent deployment, and reduced anticoagulation with antiplatelet treatment alone, multiple coronary stenting may be performed with a high procedural success rate and good intermediate term outcome.

Improved Clinical Outcome After Widespread Use of Coronary-Artery Stenting in Canada

BACKGROUND The introduction and refinement of coronary-artery stenting dramatically changed the practice of percutaneous coronary revascularization in the mid-1990s. We analyzed one-year follow-up data for all percutaneous coronary interventions performed in a large, unselected population in Canada to determine whether the use of coronary stenting has been associated with improved outcomes. METHODS Prospectively collected data on all percutaneous coronary interventions performed on residents of British Columbia, Canada, between April 1994 and June 1997 were linked to province-wide health care data bases to provide the date of the following end points: subsequent target-vessel revascularization, myocardial infarction, and death. Baseline characteristics and procedural variables were identified and Kaplan-Meier survival curves were generated for 9594 procedures divided into seven groups, one for each sequential half-year period. RESULTS The overall burden of coexisting illnesses remained stable throughout the study period. A large increase in the rate of coronary stenting (from 14.2 percent in the period from April to June 1994 to 58.7 percent in the period from January to June 1997) was associated with a significant reduction in the rate of adverse cardiac events at one year (from 28.8 percent to 22.8.percent; adjusted relative risk, 0.79; 95 percent confidence interval, 0.69 to 0.90; P<0.001). This reduction in adverse events was exclusively due to a large reduction in subsequent target-vessel revascularization (from 24.4 percent to 17.0 percent; adjusted relative risk, 0.72; 95 percent confidence interval, 0.62 to 0.83; P<0.001) without significant changes in the overall rates of myocardial infarction (5.4 percent, P=0.28) or death (3.9 percent, P=0.65). CONCLUSIONS The need for target-vessel revascularization during one year of follow-up decreased after percutaneous coronary intervention during the mid-1990s. The reduction was coincident with the introduction and subsequent widespread use of coronary stenting.