Comparison of elective Wiktor stent placement with conventional balloon angioplasty for new-onset lesions of the right coronary artery

Are "treatment" bare metal stents superior to "control" bare metal stents? A meta-analytic approach

BACKGROUND

It has been suggested that the benefits of drug-eluting stents compared to bare metal stents (BMS) have been overestimated in part because target lesion/vessel revascularization (TLR/TVR) rates in the BMS control group of these trials were spuriously high.

METHODS

We used meta-analytic techniques to systematically compare clinical event rates among patients treated with BMS in trials where BMS were the experimental (BMS(experimental)) rather than the control (BMS(control)) intervention. MEDLINE searches were performed to identify eligible randomized trials comparing either drug-eluting stents with BMS(control) or BMS(experimental) with balloon angioplasty in patients with nonacute coronary artery disease. Trial characteristics and 6- to 12-month rates for death, myocardial infarction, TLR/TVR, and major adverse cardiac events were extracted and assessed.

RESULTS

Eligible trials yielded 50 BMS cohorts: 19 in the BMS(control) group (4046 patients) and 31 in the BMS(experimental) group (5068 patients). Summary death and infarction rates did not differ between groups. The summary TLR/TVR rates were 16.2% (95% CI 13.5-19.3) versus 13.8% (95% CI 12.0-15.7) in BMS(control) versus BMS(experimental) groups, respectively (P = .15). Among 39 BMS cohorts with < or = 250 patients, TLR/TVR rates were significantly higher in BMS(control) versus BMS(experimental) groups (18.9% [95% CI 16.0-22.2] vs 13.7% [95% CI 11.5-16.3], P = .01). There were no between-group differences among larger BMS cohorts (P = .98).

CONCLUSIONS

Although overall clinical event rates did not differ in the BMS(control) and the BMS(experimental) groups, a higher rate of TVR/TLR was seen in the BMS(control) group among smaller trials.

Primary stenting versus primary balloon angioplasty for treating acute myocardial infarction

BACKGROUND

Balloon angioplasty following myocardial infarction (MI) reduces death, non-fatal MI and stroke compared to thrombolytic reperfusion. However up to 50% of patients experience restenosis and 3% to 5% recurrent myocardial infarction. Therefore, primary stenting may offer additional benefits compared to balloon angioplasty in patients with acute myocardial infarction.

OBJECTIVES

To examine whether primary stenting compared to primary balloon angioplasty reduces clinical outcomes in patients with acute myocardial infarction.

SEARCH STRATEGY

We searched MEDLINE, EMBASE, Pascal, Index medicus and The Cochrane Controlled Trials Register (The Cochrane Library) from 1979 to March 2002.

SELECTION CRITERIA

Randomised controlled trials of primary stenting or balloon angioplasty prior to the invasive procedure; intervention in native coronary arteries within 24 hours after onset of symptoms of myocardial infarction; report of death or reinfarction; and follow-up of at least 1 month. Trials were excluded when randomisation occurred after an invasive procedure and if they exclusively included patients with cardiogenic shock.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected and extracted data from identified trials. Outcomes included mortality, reinfarction, coronary artery bypass grafting, target vessel revascularization, need for vascular repair or blood transfusion. Peto odds ratios were calculated. To explore the stability of the overall treatment effect various sensitivity analyses were performed.

MAIN RESULTS

We included nine trials of 4433 participants. Odds ratios for mortality after stenting compared to balloon angioplasty at 30 days, 6 and 12 months were 1.16 (95% CI 0.78 to 1.73), 1.27 (95% CI 0.89 to 1.83), and 1.06 (95% CI 0.77 to 1.45). At 30 days, 6 and 12 months odds ratios for reinfarction after stenting compared to balloon angioplasty were 0.52 (95% CI 0.31 to 0.87), 0.67 (95% CI 0.45 to 1.00), and 0.67 (95% CI 0.45-0.98) and odds ratio for target vessel revascularization after stenting compared to balloon angioplasty were 0.45 (95%CI 0.34 to 0.60), 0.42 (95% CI 0.35 to 0.51), and 0.47 (95% CI 0.38 to 0.57). The odds ratio for post-interventional bleeding complications after stenting compared to balloon angioplasty was 1.34 (95% CI 0.95 to 1.88; test of heterogeneity p > 0.1).

AUTHORS' CONCLUSIONS

There is no evidence to suggest that primary stenting reduces mortality when compared to balloon angioplasty. Stenting seems to be associated with a reduced risk of reinfarction and target vessel revascularization, but potential confounding due to unbalanced post-interventional antithrombotic/anticoagulant therapies can not be ruled out on basis of this review.

Angiographic and clinical outcome of a new self-expanding intracoronary stent (RADIUS): results from multicenter experience in Japan

The RADIUS coronary stent featuring a multisegmented slotted tube design and self-expanding nitinol delivery system has a high radial force and flexibility, uniform expansion, and contours to the shape of the vessel. Successful stent deployment was achieved in 104 stable angina patients (106 lesions; 44% LAD, 19% circumflex, and 37% RCA). Mean minimal lumen diameter (MLD) increased from 0.77 +/- 0.46 mm to 2.88 +/- 0.61 mm and mean percent diameter stenosis (% DS) decreased from 73 +/- 14% to 6 +/- 13% immediately after the procedure. At 6-month follow-up, two patients (2%) underwent urgent target revascularization, and cerebral bleeding occurred in one patient (1%). Angiographic follow-up was performed in 94 lesions (89%) and mean MLD and mean % DS were 2.08 +/- 0.92 mm and 30% +/- 24%, respectively. Stent restenosis (>50% diameter stenosis at follow-up) was observed in 16 (17%) of all lesions. The high success rate for stent deployment, low incidence of major adverse cardiac event, and lower restenosis rate after stent implantation indicate that the RADIUS stent is useful for coronary intervention.

Benefit of intravascular ultrasound in Wiktor stent implantation

The goal of this study was to evaluate retrospectively the efficacy and safety of intravascular ultrasound (IVUS) during Wiktor stent implantation. Until 1996, the success of stent implantation was assessed by angiographic criteria only, but in 1997, the procedure was expanded to include pre- and postprocedural IVUS imaging. Sixty-six patients were included, 28 treated in 1996 (group A) and 38 treated in 1997 (group B). Stent size was larger in group B than in group A (3.6+/-0.4 vs. 3.1+/-0.2, P < 0.001). Acute gain was greater in group B than in group A (2.58+/-0.61 vs. 2.11+/-0.56, P < 0.001). Restenosis rate was 31% in group A and 14% in group B. No major acute complications due to IVUS examination occurred. IVUS is helpful in choosing optimal stent size.

Acute directional coronary atherectomy prior to stenting in complex coronary lesions: ADAPTS Study

The purpose of this study was to determine the results of directional coronary atherectomy (DCA) combined with stenting in a high-risk patient population. The use of stenting or DCA alone for aorto-ostial lesions, total chronic occlusions, long lesions, and lesions containing thrombus is associated with lowered success and a relatively high restenosis rate. Between July 1993 and October 1996, we treated 89 lesions with the combined approach of DCA and stenting in 60 consecutive patients. Thirty-one (51.7%) patients were treated because of unstable angina, 11 (18.3%) for post-myocardial infarction (MI) angina, 3 (5.0%) for acute MI, and 15 (25.0%) patients for stable angina. A total of 43 (71.7%) patients had multivessel disease, 19 (31.7%) had undergone previous coronary artery bypass graft (CABG), and 17 (28.3%) patients had undergone multivessel revascularization. The procedure was successful in all patients; and no postprocedural deaths or emergent CABG occurred. Two patients (3.3%) had non-Q-wave MI after the procedure and 1 patient (1.7%) experienced Q-wave MI due to subacute stent closure 7 days after the procedure. During follow-up ranging from 6 months to 3 years, 2 (3.3%) patients died, 2 (3.3%) required CABG surgery, 1 (1.7%) patient had an MI, and 6 patients (10.0%) required target vessel revascularization. By the quantitative coronary angiography, the initial minimal luminal diameter (MLD) averaged 0.91+/-0.45 mm (74.7+/-11.8% stenosis) increasing to 3.80+/-0.44 mm (-6.7+/-12.1%) after the combined approach procedure. Thirty patients (50.0%) met criteria for late (> or =6 months) angiographic follow-up. Late MLD loss averaged 1.13+/-1.07 mm, for a mean net gain of 1.61+/-1.23 mm. Available angiographic follow-up evaluation showed a restenosis rate of 13.3%. A combined approach, defined as the use of both DCA and stenting, is safe and yields a low restenosis rate in high-risk patients who have lesions known to respond less favorably to stenting or DCA alone.