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


Therapeutics

Immediate angioplasty was better than streptokinase in acute MI

ACP J Club. 1994 Sept-Oct;121:42. doi:10.7326/ACPJC-1994-121-2-042

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Source Citation

de Boer MJ, Hoorntje JC, Ottervanger JP, Reiffers S, Suryapranata H, et al. Immediate coronary angioplasty versus intravenous streptokinase in acute myocardial infarction: left ventricular ejection fraction, hospital mortality and reinfarction. J Am Coll Cardiol. 1994 Apr;23:1004-8.


Abstract

Objective

To examine the differences in mortality, reinfarction, and left ventricular function in patients with acute myocardial infarction (MI) treated with coronary angioplasty compared with intravenous streptokinase.

Design

3-year randomized, single-blind controlled trial.

Setting

Coronary care unit in the Netherlands.

Patients

301 patients (mean age 60 y, 248 [82%] men) were eligible if they were aged < 76 years; had symptoms of acute MI for > 30 minutes; presented within 6 hours after symptom onset or between 6 and 24 hours if evidence of continuing ischemia existed; and had no contraindication to thrombolytic intervention.

Intervention

Patients were randomly assigned to receive intravenous streptokinase, 1.5 million U in 1 hour (n = 149), or immediate coronary angioplasty (n = 152) if their coronary anatomy was deemed suitable by coronary angiography. 140 of the 152 patients assigned to angioplasty received it. 1 patient assigned to receive streptokinase died after randomization.

Main outcome measures

Death, recurrent MI before hospital discharge, and radionuclide-measured left ventricular ejection fraction before discharge. Recurrences were defined as chest pain with changes in ST-T waves or new Q-waves and a second increase in creatine kinase levels of > 2 times the upper limit of normal or over the previous value if it had not decreased below the upper limit of normal.

Main results

3 patients (2%) in the angioplasty group died compared with 11 (7%) in the streptokinase group (P = 0.02) (Table). Recurrent MI occurred in 2 patients (1%) in the angioplasty group compared with 15 (10%) in the streptokinase group (P < 0.001) (Table). Patients in the angioplasty group had a higher mean left ventricular ejection fraction compared with patients in the streptokinase group (50% [SD 11%] vs 44% [SD 11%], P < 0.001).

Conclusion

Immediate coronary angioplasty resulted in lower rates of hospital mortality and reinfarction and in higher left ventricular ejection fraction compared with intravenous streptokinase in patients with acute myocardial infarction.

Source of funding: The Netherlands Heart Foundation.

For article reprint: Dr. F. Zijlstra, Hospital de Weezenlanden, Department of Cardiology, Groot Wezenland 20, 8011 JW Zwolle, the Netherlands. FAX 31-38-230-005.


Table. Immediate coronary angioplasty vs intravenous streptokinase*

Outcomes at hospital discharge Immediate coronary angioplasty Intravenous streptokinase RRR (95% CI) NNT (CI)
Death 2% 7% 73% (13 to 92) 19 (10 to 138)
Myocardial infarction 1% 10% 87% (50 to 97) 12 ( 7 to 26)

*Abbreviations defined in Glossary; RRR, NNT, and CI calculated from data in article.


Commentary

Rapid, early restoration of brisk coronary blood flow improves the outcomes in acute MI. Clinical trials have shown that either pharmacologic or mechanical methods of coronary reperfusion are effective, but the relative merits of alternative methods to achieve and sustain reperfusion are not completely established. Because coronary angioplasty can reduce residual coronary stenoses as well as break up most thrombi, it was hypothesized that percutaneous transluminal coronary angioplasty (PTCA) would improve outcomes in patients with acute MI. Several early randomized trials showed that PTCA immediately after thrombolysis actually worsened outcomes, probably because of increased complications of PTCA in the lytic state. Several recent randomized trials show that using PTCA instead of thrombolysis (primary PTCA) leads to equivalent or even better outcomes (mortality, reinfarction, stroke, left ventricular function). All PTCA trials have been done by highly experienced operators in centers committed to providing emergency PTCA. Because PTCA results are operator-dependent, these findings cannot necessarily be generalized to the "average" center.

Primary PTCA in MI requires considerable resources, including a laboratory and support staff available to provide PTCA within 60 minutes at any time of the day or night. The reported trials suggest that PTCA may be economically competitive with thrombolysis, but most patients given thrombolysis in these trials had predischarge coronary angiography and revascularization anyway (1)

Subsequent studies confirm the overall benefits of primary PTCA compared with thrombolysis in acute ST-segment elevation MI (2-4). A cost-effectiveness analysis suggests that primary angioplasty is cost-effective in existing high-volume cardiac catheterization laboratories, but that construction of new laboratories to provide primary PTCA is not justified (5). Primary PTCA for acute MI should be strongly considered when it can be done in < 1 hour by an experienced operator.

Mark A. Hlatky, MD
Stanford University School of MedicineStanford, California, USA


References

1. Reeder GS, Bailey KR, Gersch BJ, et al. Cost comparison of immediate angioplasty versus thrombolysis followed by conservative therapy for acute myocardial infarction: a randomized prospective trial. Mayo Coronary Care Unit and Catheterization Laboratory Groups. Mayo Clin Proc. 1994;69:5-12.

2. The Global Use of Strategies to Open Occluded Coronary Arteries in Acute Coronary Syndromes (GUSTO IIb). Angioplasty Substudy Investigators. A clinical trial comparing primary coronary angioplasty with tissue plasminogen activator for acute myocardial infarction. N Engl J Med. 1997 336:1621-8.

3. Zijlstra F, Beukema WP, van't Hof AW, et al. Randomized comparison of primary coronary angioplasty with thrombolytic therapy in low risk patients with acute myocardial infarction. J Am Coll Cardiol. 1997; 29:908-12.

4. Weaver WD, Simes RJ, Betriu A, et al. Comparison of primary coronary angioplasty and intravenous thrombolytic therapy for acute myocardial infarction: a quantitative review. JAMA. 1997;278:2093-8.

5. Lieu TA, Gurley RJ, Lundstrom RJ, et al. Projected cost-effectiveness of primary angioplasty for acute myocardial infarction. J Am Coll Cardiol. 1997;30:1741-50.