Late Restenosis Rate Research Articles

Results of Coronary Stenting for Restenosis

Objectives. This study attempted to analyze immediate and long-term angiographic and clinical results of coronary stent implantation for restenosis in a consecutive group of patients.Background. The rate of stent utilization in patients with coronary artery disease has increased exponentially in recent years. There are many unanswered questions about the use of stenting in patients with restenosis, particularly with respect to late clinical and angiographic results.Methods. A total of 159 stents were implanted in 128 consecutive patients with 139 lesions (mean 1.3 stents/patient). A technique of optimal stent expansion was used in all patients, and intravascular ultrasound guidance with no subsequent anticoagulation was performed in 41 patients.Results. Stent implantation was successful in 126 patients (98%). Four patients (3.1%) had complications (in two after successful stenting): death in one, emergency bypass surgery operation in two and subacute stent thrombosis in one. Stents were implanted with a final balloon size (mean ± SD) of 3.5 ± 0.5 mm and a mean maximal pressure of 11 ± 4 atm (range 8 to 20). Angiographic restenosis occurred in 27 patients (25%). Regression analysis on clinical and angiographic variables for prediction of restenosis showed no statistical significance for any variable. Late events occurred in 23 patients (19%). The actuarial survival rate was 98% at 1 year and at 3 years, and the event-free survival rate including freedom from repeat angioplasty for restenosis was 95% and 76%, respectively.Conclusions. The late angiographic outcome, restenosis rate and total clinical events are favorable for selected patients undergoing stent implantation for the indication of restenosis.

Clinical Experience with Wiktor Stent Implantation: A Report from the French Multicentric Registry

Our objective was to evaluate, in a French multicenter study, the results of implantation of Wiktor tantalum wire coronary stents in stenosed or occluded coronary vessels or in saphenous vein bypass grafts. The study was a retrospective analysis of clinical and angiographic data from patients treated with tantalum wire stent implanted at five centers. Stenting of native coronary arteries or saphenous vein bypass grafts was attempted in 272 patients after acute or threatened closure of the target vessel, or because the lesions concerned were considered to be at particularly high risk of becoming restenosed, or because the result of primary angioplasty was inadequate. Successful stent deployment was achieved in 261 95.9%) of 272 patients. The incidence of major complications such as death, myocardial infarction (MI), or a condition requiring urgent bypass surgery was 8.1%. Major vascular complications occurred in 2.6% and actually decreased with a new anticoagulant regimen. Angiographic follow-up at a mean of 6 months after stenting showed restenosis in 23.6% with a more frequent restenosis in the group with stent size equal to 3 mm than in the group with stent size superior to 3 mm (46.1% vs 13.7%, P < 0.01). Stenting with the Wiktor tantalum wire stent is an effective means of treating acute complications and suboptimal results after angioplasty. This stent seems to offer hope of a significant reduction in the rate of late restenosis in native coronary vessels, but a prospective comparison of balloon angioplasty and stenting is needed.

Aggressive Intervention for Myocardial Infarction: Angioplasty, Stents, and Intra-aortic Balloon Pumping

Primary percutaneous transluminal coronary angioplasty (PTCA) is not used in all hospitals capable of performing it because the data regarding results are either not known or not easily interpreted. Unlike pharmaceutical trials, which receive $30–50 million in research funds, virtually all trials of PTCA have been unfunded. Nevertheless, several groups have conclusively proved the benefit of primary PTCA over thrombolysis. In a 1995 meta-analysis, PTCA proved superior to thrombolytic therapy in reducing death and reinfarction. The Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-IIB) substudy confirmed this fact with 94% certainty. Other studies were designed to refine the angioplasty technique. In the Primary Angioplasty in Myocardial Infarction (PAMI-I) study, acute catheterization was used to stratify patients and identified a low-risk population whose mortality equaled that of patients treated electively. Compared with clinical risk factors, angiographic findings enhanced the power to predict mortality three-fold. The high-risk subset with acute myocardial infarction (MI) was also randomized to treatment with or without prophylactic intra-aortic balloon pumping (IABP). Although IABP caused no complications, it had no positive effect on primary endpoints (death, recurrent MI, and reocclusion) and did not improve left ventricular function at 6 months. One limitation of primary PTCA is a high rate of late restenosis (30–50% at 6 months). In a pilot study we are examining the role of stents in conjunction with primary PTCA. Early results indicate that in the 69% of patients eligible for stent placement, in-hospital events were uncommon (no deaths, no reinfarctions, low rate of recurrent ischemia) and the need for repeat revascularization was infrequent. (Am J Cardiol 1996;78(suppl 3A):29–34)

710-3 Stent Placement is Safe and Effective in the Treatment of Older (>4 Years) Saphenous Vein Graft Lesions

Conventional balloon angioplasty (PTCA) in older (&gt;4 years) saphenous vein grafts (SVGs) is associated with reduced procedural success and less favorable late clinical outcomes. To determine if stent (S) implantation neutralizes the adverse effects of SVG age on clinical events, we analyzed the early and late results of 617 consecutive pts from the Palmaz-Schatz SVG S registry. In 69 pts (13.3%), SVG age was ≤4 (mean 2.1 ± 1.3) years and in 448 pts (86.7%), SVG age was &gt;4 (mean 9.9 ± 3.5) years. There were no significant differences in pt demographics and lesion characteristics between the 2 groups. Procedural success was defined as successful S deployment with &lt;50% residual stenosis without major complications (death/Q-wave MI/CABG). Follow-up angiograms were obtained in 63% of pts with SVG ≤ 4 years and in 60% of pts with SVG &gt; 4 years. MLD = minimal lumen diameter. SVG Age ≤ 4 years SVG Age &gt;4 years Angiographic Findings: Final MLD (mm) [% stenosis] 3.3 ± 0.7 [7 ± 12] 3.4 ± 0.6 [6 ± 10] Follow-up MLD [% stenosis] 2.1 ± 1.3 [42 ± 36] 2.3 ± 1.3 [33 ± 36] Restenosis (&gt;50% stenosis) 35.6 28.7 Clinical Results: 1%) Procedural success 97.1 97.0 In hospital death/O-wave MI/CABG 14/0/14 1.7/04/09 Follow-up target lesion CABG/PICA 57/143 54/9.5 12·month event free survival 73.0 77.0 All comparisons between the 2 groups were not statistically significant. After S placement, irrespective of SVG age, 1) acute and late angiographic results and restenosis rates were similar and 2) clinical results (i.e. procedural success, major complications, target lesion revascularization and 12-months event free survival) were comparable. Thus, unlike PTCA, in appropriate SVG lesions, the favorable early and 12-month clinical outcomes after S therapy are not diminished by advanced SVG age.

751-1 Efficacy of Tranilast on Restenosis After Coronary Angioplasty: is There Any Rebound Phenomenon After Ceasing Tranilast at 3 Months?

Tranilast, an anti-allergic drug, is also effective for the prevention of keloid. We have already reported that 3 months (mos) administration of tranilast limited restenosis at 3 mos. To elucidate the efficacy of 3 mos administration of tranilast for the prevention of restenosis at 6 mas after angioplasty, patients with stable effort angina were studied with following 3 conditions. (1) ACC/AHA type A lesion, (2) reference vessel diameter ≥ 2.5 mm, (3) more than 20% improvement of % stenosis after angioplasty with smooth dilatation. One hundred lesions (group T) were treated with tranilast 600 mg/day for 3 mos and administrations were ceased at the end of 3 mos. Control group (group C) consists of 105 lesions matched with group T. Both group T and Creceived antiplatelet agents, nitrates and Ca antagonists. Angiographic follow-up was done at 3 and 6 mas after angioplasty. More than 50% loss of % stenosis gained by angioplasty was defined as restenosis. Resu/ts: (1) Changes in % stenosis: group T (vs group C); before angioplasty 73.4% ± 12.3% (71.1% ± 11.5%, ns). immediately after angioplasty 12.8% ± 11.6% (18.5% ± 11.0%, ns), at 3 mos 25.8% ± 18.2% (33.2 ± 26.8%, P &lt; 0.01). at 6 mos 22.0% ± 14.1% (32.3% ± 21.4%, nsl. (2) Restenosis rate: group T (vs C); at 3 mas 15.0% (38.1%, p &lt; 0.01) , at 6 mos 22.0% (45.7% , P &lt; 0.01) . Group T showed lower restenosis rate at 3 mos and at 6 mos, and ceasing tranilast at 3 mos did not increase the late restenosis rate. There is no rebound phenomenon after ceasing tranilast treatment. Thus, 3 mos administration of tranilast is sufficient to limit restenosis at 6 mos following angioplasty.

Restenosis after successful emergency coronary angioplasty for acute myocardial infarction; comparison with elective angioplasty

We investigated the initial and late restenosis rate after successful emergency coronary angioplasty in 64 patients with acute myocardial infarction, and compared these results with those of 100 patients (110 lesions) who had successful angioplasty on an elective basis. The majority of the baseline clinical and angiographic variables were similar in the myocardial infarction and elective groups. The restenosis rate at 1 month was high in patients undergoing emergency angioplasty for acute myocardial infarction (23 vs. 12%). At 3–6 months, the angiographie restenosis rate was low for the infarction group (26 vs. 37%). The overall restenosis rate was similar in the infarction and elective groups (39 vs. 40%). Lesion regression after coronary angioplasty was more frequent in the infarction than in the elective angioplasty group (27 vs. 14%, P < 0.05). These findings suggest that considering the high restenosis rate at 1 month and the lower, but still 20% or more, rate at 3–6 months, a follow-up angiography should be performed both prior to discharge and at 3–6 months after the procedure, in patients with acute myocardial infarction.

Clinical experience with the Wiktor stent in native coronary arteries and coronary bypass grafts.

To evaluate the results of implantation of Wiktor tantalum wire coronary stents in stenosed or occluded coronary vessels or in saphenous vein bypass grafts. A retrospective analysis of clinical and angiographic data from patients treated with tantalum wire stents implanted by one operator at two centres. 52 patients undergoing conventional balloon angioplasty had 67 lesions treated by stents after acute or threatened closure of the target vessel, or because the lesions concerned were considered to be at particularly high risk of becoming restenosed, or because the result of primary angioplasty was inadequate. 65 of the 67 lesions were successfully stented although in two cases the first attempt failed and a second stent was then implanted successfully. There were no cases of stent occlusion and no myocardial infarctions in hospital or in the follow up period of 1-20 months. Eight patients had haemorrhagic complications that were minor in 4. One patient later had coronary bypass surgery after failure to stent a lesion. Angiographic follow up at a mean of 6 months after stenting showed restenosis associated with 4 of 47 stents studied. All patients with chest pain had had repeat angiography, and 84% of those without symptoms also agreed to reinvestigation after about 6 months. The Wiktor tantalum wire stent is an effective means of treating acute complications during angioplasty and seems to offer hope of a significant reduction in the rate of late restenosis in both native coronary vessels and saphenous vein bypass grafts. A prospective comparison of balloon angioplasty and stenting is needed.

Early luminal deterioration following successful percutaneous transluminal coronary angioplasty

In order to develop a predictive model for the risk of early lesion deterioration following successful coronary balloon angioplasty (PTCA) based on clinical, pre-angioplasty and procedural characteristics, 154 lesions in 146 consecutive patients undergoing successful PTCA for stable/unstable angina were examined by quantitative coronary analysis immediately after and within 24 h of angioplasty. An angiographic complication score was used prospectively, classifying the lesion morphology post-PTCA into class 0: no complication and classes 1 to 3, according to purely descriptive morphological characteristics. Significant deterioration, defined as a decrease in minimal luminal diameter of more than 2 standard deviations of duplicate measurements post-intervention (0.54 mm; 95% confidence limit for variability using quantitative angiography) was found in 28 lesions (18%), and a total reocclusion in seven lesions (5%). The angiographic complication score (P = 0.019), prior to myocardial infarction (P = 0.076), minimal luminal diameter immediately post-intervention (P = 0.021) and gain of PTCA (P = 0.042) were found to be independently predictive of early lesion deterioration by multiple logistic regression analysis. Identification of these factors and their associated risk should improve success, and understanding of the early vascular response following coronary angioplasty. Moreover, these results have implications for clinical restenosis studies, particularly those assessing the effect of pharmacological interventions on late restenosis rates.

Long-term clinical and angiographic follow-up after placement of Palmaz-Schatz coronary stent: a single center experience.

The purpose of this study is to evaluate long-term clinical and angiographic follow-up results after placement of the Palmaz-Schatz stent and angiographic follow-up results of repeat interventions for stent restenosis. From June 1990 to September 1993, the Palmaz-Schatz stent was placed in 411 patients, 427 lesions. Follow-up angiography was performed in 307 lesions at 3-6 months and in 189 lesions at 1 year. Palmaz-Schatz stent implantation resulted in 97.2% procedure success and 94.6% clinical success. Stent thrombosis was observed in 2.2%. Angiographic restenosis rate was 16.3% at 3-6 months study. At 1 year study, "new" restenosis occurred only in 2.3%. Minimal lumen diameter did not change between 6 months and 1 year (2.32 +/- 0.51 mm vs 2.30 +/- 0.54 mm). With the mean follow-up interval of 22 +/- 9 months, cardiac event-free survival was achieved in 74.3%. Among 50 lesions with restenosis, stent restenosis occurred diffusely in 15 lesions (30%), focally inside the stent in 22 lesions (44%) and focally at the stent border in 13 lesions (26%). Repeat interventions were performed in 35 lesions. Restenosis at 3 months after repeat intervention was demonstrated in 9 (32.1%) out of 28 lesions restudied. Restenosis rate after repeat intervention for diffuse stent restenosis was significantly higher than that for focal in-stent restenosis (75% vs 7.7%). Palmaz-Schatz stent implantation was associated with a high initial success rate and a low late restenosis rate. Luminal renarrowing did not occur beyond 6 months up to 1 year.

Serial angiographic follow-up after palmaz-schatz stent implantation: Comparison with conventional balloon angioplasty

Objectives. Serial angiographic follow-up study was designed to evaluate the temporal mode of lumen diameter changes after Palmaz-Schatz stent implantation, and the results were compared with those from a cohort of patients undergoing balloon angioplasty.Background. Restenosis remains a major limitation of balloon angioplasty. The Palmaz-Schatz balloon expandable coronary stent is now under clinical investigation to evaluate its efficacy in preventing restenosis.Methods. Serial angiographic follow-up study was performed the day after stent implantation and at 1, 3 and 6 months after the procedure. The stent group consisted of 96 patients who had 97 lesions with a single stent. A cohort of 179 patients with 192 lesions were selected as the balloon group by the criteria of final balloon size ≥3 mm and lesion length <20 mm.Results. A significantly larger lumen diameter was obtained immediately after stent implantation (2.9 ± 0.4 mm [mean ± SD] in the stent group vs. 2.1 ± 0.5 mm in the balloon group, p < 0.001). At 3 to 6 months of follow-up, a significantly larger lumen diameter was maintained in the start group (2.2 ± 0.6 vs. 1.5 ± 9.7 mm, p < 0.001). The late restenosis rate according to a binary definition was significantly lower to the stent group (13% vs. 39%, p < 0.001). Stenosis exacerbation, frequently observed within 24 h after balloon angioplasty, was not found after stenting. Between the next day and 1 month, regression was dominant in the balloon group, whereas progression of stenosis was observed in the stent group. The greatest tendency to restenosis was observed in both groups between 1 and 3 months after the procedure. Between 3 and 6 months, significantly greater diameter loss was found in the stent group.Conclusions. The Palmaz-Schatz stent was effective in reducing the restenosis rate in this highly selected cobort of patients. Reduction in restenosis rate was dependent on a larger lumen obtained immediately. Late loss of diameter was significantly greater after stenting. The restenosis rate after stenting should be evaluated by follw-up angiography at 6 months rather than at 3 months, which is adequate after conventional balloon angioplasty.

Quantitative angiographic follow-up of the coronary Wallstent in native vessels and bypass grafts (European experience — March 1986 to March 1990)

The coronary stent has been investigated as an adjunct to percutaneous transluminal coronary angioplasty to obviate the problems of early occlusion and late restenosis. From March 1986 to March 1990, 265 patients (308 lesions) were implanted with the coronary Wallstent ® in 6 European centers. For this study, the patients were analyzed according to date of implantation (group 1, March 1986 to January 1988; group 2, February 1988 to March 1990) and vessel type (native arteries versus bypass grafts). Quantitative angiographic follow-up was performed in 82% of the study patients. The early in-hospital occlusion rate in the overall group was 15%. Group 1 patients had a 20% rate in contrast to 12% rate in group 2 (p = not significant [NS]). The early occlusion rate in native vessels and bypass grafts was 19 and 8%, respectively (p = 0.019). Restenosis was determined by 2 criteria (criterion 1, ≥0.72 mm loss in minimal luminal diameter from poststent to follow-up; criterion 2, ≥50% diameter stenosis at follow-up) within the stent and in the segments immediately proximal and distal to the stent. The restenosis rate with criterion 1 was 43% in the overall group of patients, 35% in group 1 versus 49% in group 2 (p = NS), and 34% in native vessels versus 54% in bypass grafts (p = 0.016). The second criterion was met by 27% of patients in the overall group, 21% in group 1 versus 32% in group 2 (p = NS), and 18% in native vessel versus 39% in bypass grafts (p = 0.005). The overall mortality during the study period was 6.6% in native arteries and 9% in bypass grafts (6 and 7.9% at 1 year, respectively). The actuarial event-free survival (freedom from death, myocardial infarction, bypass surgery or angioplasty) for native artery patients was 46% at 40 months and for bypass graft patients 37% at 20 months. It is concluded that early in-hospital occlusions remain a major problem with this device despite improvement in the later experience. Although patients with bypass grafts had a significantly lower early occlusion rate than those with implantation of native arteries, a significantly higher rate of late restenosis limited the early benefits of stenting. The indications for stenting remain unknown and require results of randomized clinical studies.

Percutaneous endovascular stenting: development, investigation and application

Percutaneous endovascular stenting (PES), a new and alternative approach of interventional radiologic techniques, has encouraging potentials for management of vascular obstructive diseases. The most important role of PES is to prevent the risk of abrupt closure and to reduce the rate of early and late post-angioplasty restenosis (PARS) of PTA. Because of different working mechanisms, various stents show different advantages and disadvantages. Specific indications of PES are: (1) further compensation for failed PTA, (2) management of complications due to PTA and (3) primary treatment of vascular obstructive diseases. Based on a preliminary comparison with atherectomy, laser angioplasty and PTA, PES seems to provide an advantage for long-term patency of large caliber vessels such as iliac arteries, while more significant problems still exist in PES with small caliber vessels such as femoral-popliteal and coronary arteries. Further comparative clinical research is required to establish the utility of PES among other intraluminal techniques of vascular interventions.

Intracoronary Stenting—Hope or Hype?

Intracoronary Stenting—Hope or Hype?

Percutaneous transluminal angioplasty versus surgery for subclavian artery occlusive disease

Twenty-one patients who underwent percutaneous transluminal angioplasty (PTA) for proximal stenosis of the subclavian artery were compared with 15 patients who underwent carotid subclavian reconstruction. This represents the first attempt to directly compare the two procedures. All patients had routine Doppler examination during follow-up. Mean follow-up was 30 ± 24 months after PTA and 40 ± 25 months after surgery. The incidences of procedural complications were similar (PTA one complication, surgery two complications). Although better early results were achieved in patients who underwent PTA (actuarial patency: PTA 91 percent, surgery 87 percent), after dilatation, we observed a continuous deterioration of the hemodynamic status of the artery, which led to a high rate of late restenosis (actuarial patency: PTA 54 percent, surgery 87 percent). There were no significant changes postoperatively. The specific role of each procedure is analyzed in view of the new acknowledgment of the clinical importance of proximal subclavian artery disease.

Late restenosis after emergent coronary angioplasty for acute myocardial infarction: Comparison with elective coronary angioplasty

The late restenosis rate after emergent percutaneous transluminal coronary angioplasty for acute myocardial infarction was assessed by performing outpatient fallow-up cardiac catheterization in 79 (87%) of 91 consecutive patients who had been discharged from the hospital with a successful coronary angioplasty. The majority of patients (90%) received high dose intravenous thrambolytic therapy with streptokinase in addition to angioplasty. Similar follow-up data were obtained in 206 (90%) of 228 consecutive patients who had successful elective angioplasty during the same period. The interval from angioplasty to follow-up was 28 ± 9 weeks for the myocardial infarction group and 30 ± 11 weeks for the elective group.Basetine clinical variables were similar for both the myocardial infarction and elective groups except for a higher percentage of men in the infarction group (81 versus 63%, p = 0.001). The number of coronary lesions undergoing angioplasty and the incidence of intimal dissection were similar, but multivessel angioplasty was more common in the elective group (13 versus 4%, p = 0.02). The rate of in-hospital reocclusion was higher in the patients receiving angioplasty for myocardial infarction (13 versus 2%, p = 0.0001). At the time of late follow-up after hospital discharge, the patients with myocardial infarction were more often asymptomatic (79 versus 55%, p = 0.0001), and the rate of angiographic coronary restenosis was lower for the infarction group both overall (19 versus 35%, p = 0.006) and when multivessel angioplasty patients were excluded (19 versus 33%, p = 0.01).These findings indicate that the rate of early reocclusion is higher and that of long-term restenosis is lower after successful emergent coronary angioplasty in the setting of thrombolytic therapy with streptokinase for acute myocardial infarction than after elective angioplasty.