Current issues of ACP Journal Club are published in Annals of Internal Medicine


Therapeutics

Benefit-risk trade-off was found for stent vs balloon coronary angioplasty

ACP J Club. 1995 Jan-Feb;122:11. doi:10.7326/ACPJC-1995-122-1-011


Source Citation

Serruys PW, de Jaegere P, Kiemeneij F, et al. A comparison of balloon-expandable-stent implantation with balloon angioplasty in patients with coronary artery disease. N Engl J Med. 1994 Aug 25;331:489-95.


Abstract

Objective

To compare the effectiveness and safety of balloon-expandable coronary artery stent implantation with that of standard balloon angioplasty in patients with stable angina pectoris and a single new lesion in a coronary artery.

Design

Randomized controlled trial with 7-month follow-up.

Setting

28 centers in Europe.

Patients

520 patients (mean age, 58 y; 81% men) with stable angina pectoris and a single new lesion < 15 mm long in a coronary artery > 3 mm in diameter. Exclusion criteria were contraindication to anticoagulant or antiplatelet therapy; unsuitability for coronary bypass surgery; an ostial lesion; a lesion at a bifurcation or in a previously grafted vessel; or a suspected intracoronary thrombus.

Intervention

259 patients were allocated to a stent implantation and 257 patients were allocated to standard balloon angioplasty.

Main Outcome Measures

The primary clinical end points were death, cerebrovascular accident, myocardial infarction (MI), need for coronary artery bypass surgery, or a second percutaneous intervention involving the previously treated lesion. The primary angiographic end point was the minimal luminal diameter at follow-up.

Main Results

The procedural success rates were 93% in the stent group and 91% in the angioplasty group. A primary clinical end point was reached by 52 patients (20.1%) in the stent group compared with 76 patients (29.6%) in the angioplasty group {95% CI for the 9.5% absolute risk reduction [ARR], 2.1% to 16.9%; P = 0.01; relative risk reduction [RRR], 32%; number needed to treat [NNT], 11; CI, 6 to 48}*. This difference was explained mainly by a reduced need for a second coronary angioplasty in the stent group (13.5% vs. 23.3%; {CI for the 9.8% ARR, 3.2% to 16.5%; P < 0.001; RRR, 42.1%; NNT, 10; CI, 6 to 31}*). The occurrence of restenosis was 22% after stent implantation compared with 32% after balloon angioplasty (P = 0.02). The incidence of bleeding and vascular complications was higher in the stent group than in the angioplasty group (14% vs. 3%; P < 0.001), as was the mean hospital stay (8.5 vs. 3.1 days; P < 0.001).

Conclusion

The clinical and angiographic outcomes were better, but bleeding and vascular complications were more frequent and hospital stay was longer, in patients with stable angina and a single coronary artery lesion who received a stent than in those who received standard coronary angioplasty.

Sources of funding: Johnson and Johnson Interventional Systems; Schneider and Co., Switzerland; Lorex Pharmaceutica, the Netherlands.

For article reprint: Dr. R.W. Serruys, Catheterization Laboratory, Thorax Center, Erasmus University Rotterdam, P.O. Box 1738, 3000 DR Rotterdam, the Netherlands. FAX 31-10-436-9154.

*Numbers calculated from data in article


Commentary

Coronary artery restenosis after balloon angioplasty occurs in 30% to 50% of patients. More than 50 randomized trials have failed to show a successful pharmacologic intervention, and the first 2 trials with directional atherectomy (1, 2) produced equivocal results. In these 2 stent trials, the angiographic results were remarkably similar for both post-procedural and follow-up minimum luminal diameter and percent diameter stenosis. Each showed an absolute 10% reduction in angiographic restenosis with stenting, a significant advance in this field.

The clinical outcome results can be interpreted in various ways. A more negative analysis than that presented by the authors can be summarized by tabulating the results for stenting rather than angioplasty in 100 patients. In the Benestent study, 10 patients were spared repeat angioplasty at a cost of 1 extra acute coronary artery closure, 2 more bypass operations, 10 extra bleeding or vascular complications, and 540 additional acute hospital days. The clinical outcome data in the Stent Restenosis Study (STRESS) are more difficult to interpret because the patients having angioplasty had a higher-than-expected bypass surgery rate (8.4%) and a lower-than-expected repeat angioplasty rate (12.4%) for a restenosis rate of 42%. For 100 patients, 1 less angioplasty and 3.5 fewer bypass operations with stenting cost 2 extra coronary artery closures, 4 more bleeding and vascular complications, and 300 extra acute hospital days. Not counted is the additional cost of the stent ($1600), procedure times that are often longer and involve more contrast medium use and radiation exposure than does angioplasty, rigorous periprocedural management, extended bed rest, and the inconvenience of monitoring anticoagulation for 1 month.

It should be noted that these trials were designed to test whether a new device was superior to balloon angioplasty in relatively large arteries ≥ 3.0 mm) that were at low risk for acute closure (short lesions, not ostial, without thrombus). It is a difficult comparison to win given the excellent results obtained by experienced high-volume operators with current angioplasty equipment. Moreover, restenosis is usually not a life-threatening condition. Most patients can be redilated electively with 1 balloon catheter and discharged from the hospital the next day.

Some coronary artery stenoses do not initially respond well to balloon angioplasty or recur despite successful angioplasty. Anecdotal experience suggests that stenting some of these lesions may produce a successful outcome. Stenting is already the treatment of choice of many for nonanastomotic saphenous vein bypass graft stenoses because restenosis rates are lower than with angioplasty (25% vs 70%). A different coronary stent used for the unstable situation of acute closure that complicates angioplasty successfully decreases the rates of acute MI and emergency bypass surgery.

It is increasingly clear that the best means of decreasing the risk for restenosis is to obtain the largest possible acute luminal diameter. More recent stent deployment strategies (larger balloons), often using intravascular ultrasound to ensure complete stent expansion, can often totally relieve the stenosis or produce a larger diameter than the reference segments, an accomplishment not consistently obtainable by other catheter interventions. Because stenting in these 2 studies reduced restenosis rates despite a residual stenosis of 20%, the studies suggest that a greater effect may be achieved. Moreover, intravascular ultrasound-guided deployment and aggressive antiplatelet drug therapy may obviate the need for anticoagulation with heparin and warfarin, which would dramatically decrease length of hospital stay and number of groin complications, altering the cost analysis. In the future, it is possible that stenting will be the treatment of choice for arteries > 3 mm in diameter. Currently, however, balloon angioplasty remains the best strategy for de novo coronary artery stenoses.

Eric R. Bates, MD
University of Michigan Medical Center Ann Arbor, Michigan