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


Therapeutics

Aspirin after PTCA had fewer treatment failures than did sulotroban

ACP J Club. 1996 May-June;124:62. doi:10.7326/ACPJC-1996-124-3-062


Source Citation

Savage MP, Goldberg S, Bove AA, et al. Effect of thromboxane A2 blockade on clinical outcome and restenosis after successful coronary angioplasty. Multi-Hospital Eastern Atlantic Restenosis Trial (M-HEART II). Circulation. 1995 Dec 1;92:3194-200.


Abstract

Objective

To determine whether aspirin or sulotroban improves clinical outcomes and reduces restenosis after percutaneous transluminal coronary angioplasty (PTCA).

Design

Randomized, double-blind, placebo-controlled trial with 6-month follow-up.

Setting

Tertiary care medical centers in the United States and Canada.

Patients

752 patients (mean age 57 y, 81% men) who were scheduled for PTCA. Exclusion criteria were Q-wave myocardial infarction (MI), thrombolytic therapy within 3 days of PTCA, and the inability to tolerate antiplatelet drugs.

Intervention

All patients received aspirin, 325 mg, on the day before PTCA. 210 of 248 patients allocated to aspirin (325 mg/d), 210 of 249 patients allocated to sulotroban (800 mg every 6 h), and 220 of 255 patients allocated to placebo had successful PTCA. After PTCA, oral anticoagulants and non-study antiplatelet agents were prohibited; antianginal agents were used as needed. Treatment was for 6 months.

Main Outcome Measures

Treatment failure within 6 months (cardiovascular death, MI, and clinically important restenosis associated with angina and revascularization). A secondary outcome was angiographic restenosis.

Main Results

Aspirin had a lower rate of treatment failure than did either sulotroban (30.2% vs 44.0%, P = 0.01) or placebo (30.2% vs 40.6%, P < 0.05). {For the first comparison, the absolute risk reduction [ARR] of 14% means that 7 patients would need to be treated with aspirin (rather than sulotroban) for 6 months to prevent 1 additional treatment failure, 95% CI 4 to 30; the relative risk reduction [RRR] was 31%, CI 8% to 49%. For the second comparison, the ARR of 10% means that 10 patients would need to be treated with aspirin (compared with placebo) for 6 months to prevent 1 additional treatment failure, CI 5 to 1081; the RRR was 25%, CI 0.2% to 45%.}* Aspirin led to a lower rate of MI than did placebo (1.2% vs 5.7%, P < 0.05), and aspirin had a lower rate of angiographic restenosis (by lesion) than did sulotroban (39% vs 53%, P = 0.006). None of the 3 groups differed for death or clinical restenosis.

Conclusion

Aspirin for 6 months after PTCA had fewer treatment failures than did sulotroban or placebo and less angiographic restenosis than did sulotroban.

Source of funding: SmithKline Beecham Pharmaceuticals.

For article reprint: Dr. M. Savage, Cardiac Catheterization Suite, 5360 Gibbon Building, Thomas Jefferson University Hospital, 111 South 11th Street, Philadelphia, PA 19107, USA. FAX 215-955-7029.

*Numbers calculated from data in article.


Commentary

The fond hope that aspirin would prevent coronary restenosis after PTCA was laid to rest by Schwartz and colleagues (1) in 1988; however, in the same study, those who were not given aspirin before PTCA had a 3-fold increase in acute coronary events associated with PTCA. A similar outcome was seen in a study that used ticlopidine before and after PTCA (2). This study by Savage and colleagues compared the use of a single aspirin tablet before PTCA with continued aspirin use and with a more selective antagonist of thromboxane metabolism, sulotroban. Although MIs were more common during follow-up in the placebo group, half of the excess events were clustered in the first 2 weeks and were likely procedure-related. Sulotroban did not offer a different degree of protection in this regard than did continued aspirin.

Angiographic rates of restenosis by lesion, a secondary outcome in this study, differed only between the aspirin (39%) and sulotroban (53%) groups. A difference in the proportion of patients with unstable angina on entry (44% vs 56%, respectively) may explain some of this difference, given the known higher propensity for restenosis in this group of patients. Thus, the difference could be more apparent than real.

The study results reinforce the point that antiplatelet drugs reduce occlusive coronary events in association with PTCA and indicate that a single aspirin tablet taken before the procedure does not confer enough protection for this purpose. Maintenance with aspirin therapy after PTCA simply reflects the pattern of the way we use this drug in overt coronary disease. The prevention of restenosis likely lies elsewhere.

Brian C. Morton, MD, CM
University of Ottawa Heart InstituteOttawa, Ontario, Canada


References

1. Schwartz L, Bourassa MG, Lesperance J, et al. Aspirin and dipyridamole in the prevention of restenosis after PTCA. N Engl J Med. 1988;318:1714-9.

2. White CW and the Ticlopidine Study Group. Antiplatelet agents are effective in reducing the acute ischemic events of angioplasty but do not prevent restenosis. Coronary Artery Disease. 1991;2:757-67.