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


Therapeutics

Primary angioplasty was marginally better than t-PA after MI

ACP J Club. 1998 Jan-Feb;128:6. doi:10.7326/ACPJC-1998-128-1-006

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Source Citation

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 Jun 5;336:1621-8.


Abstract

Objective

To compare primary angioplasty with recombinant tissue plasminogen activator (t-PA) in acute myocardial infarction (MI) with ST-segment elevation.

Design

Randomized controlled trial with 6-month follow-up using a factorial design.

Setting

57 hospitals in 9 countries.

Patients

1138 patients (77% men) who presented to the hospital within 12 hours of onset of symptoms of acute MI. {Exclusion criteria were treatment with warfarin, active bleeding, history of stroke, contraindications to heparin, renal insufficiency, systolic blood pressure > 200 mm Hg or diastolic blood pressure > 110 mm Hg, or potential for pregnancy.}*

Intervention

Patients were allocated to primary coronary angioplasty (n = 565) or to accelerated t-PA (maximum total dose 100 mg) (n = 573). The first 1012 patients were also allocated to heparin or hirudin for 3 to 5 days.

Main outcome measures

The primary outcome was a composite end point of death, nonfatal reinfarction, and nonfatal disabling stroke within 30 days. Secondary outcomes were death alone; a composite end point of death, reinfarction, stroke, and congestive heart failure (CHF); recurrent ischemia; and major bleeding.

Main results

Analysis was by intention to treat. The primary composite outcome occurred in fewer patients who received angioplasty than those who received t-PA (P = 0.033) (Table). Most of the relative benefit of angioplasty occurred between 5 and 10 days after MI. At 6 months, the groups did not differ for the primary outcome. Angioplasty was associated with fewer secondary outcomes than t-PA, and only intracranial hemorrhage reached statistical significance (0% vs 1.4%, {P < 0.005}†). No differences occurred between angioplasty plus heparin compared with angioplasty plus hirudin.

Conclusion

A modest benefit was found with the use of angioplasty compared with tissue plasminogen activator in patients with acute myocardial infarction and electrocardiographic evidence of ST-segment elevation.

Sources of funding: Guidant Corporation and Ciba-Geigy.

For article reprint: Dr. S.G. Ellis, The Cleveland Clinic Foundation, 9500 Euclid Avenue, F-25, Cleveland, OH 44195, USA. FAX 216-445-6714.

*Gusto IIb Investigators. N Engl J Med. 1996;335:775-82.

P value calculated from data in article.


Table. Angioplasty vs tissue plasminogen activator (t-PA)‡

Outcome at 30 d Angioplasty EER t-PA CER RRR (5% CI) ARR |EER-CER| NNT (CI)
Death, reinfarction, or stroke 9.6% 13.6% 29.8% (2.8 to 49.3) 4.0% 25 (13 to 296)

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


Commentary

Thrombotic occlusion of a coronary artery is the primary cause of an acute MI. Prompt restoration of antegrade flow through the occluded artery is associated with improved survival, limitation of infarction size, and improved left ventricular function. Potential approaches to restoration of flow include angioplasty, thrombolytic therapy, or coronary artery bypass grafting. Few centers can mobilize a surgical team quickly enough to do a bypass procedure. Therefore, angioplasty and thrombolysis are the 2 approaches currently being debated for the immediate treatment of patients with acute MI.

Routine immediate angioplasty or delayed post-thrombolytic angioplasty have not been shown to improve survival (1). As an alternative to thrombolysis, immediate angioplasty may offer some advantages but is only available in approximately 15% of hospitals in the United States. In an earlier report from the GUSTO trial group, U.S. patients who had an MI were compared with Canadian patients. U.S. patients were more likely to receive angioplasty and had better functional outcomes (2). The current GUSTO report shows a modest short-term benefit for a combined outcome but not for survival alone. Longer follow-up did not reveal substantial differences. At present, angioplasty, if immediately available, is a clear alternative for patients with contraindications to thrombolysis and should be considered in patients with large infarctions and hemodynamic instability. However, thrombolysis is more widely available.

Brian P. Schmitt, MD
Northwestern University Medical SchoolChicago, Illinois, USA

Brian P. Schmitt, MD
Northwestern University Medical School
Chicago, Illinois, USA


References

1. Bates DW, Miller E, Bernstein SJ, Hauptman PI, Leape LL. Coronary angiography and angioplasty after acute myocardial infarction. Ann Intern Med. 1997; 126:539-50.

2. Mark DB, Naylor CD, Hlatky MA, et al. Use of medical resources and quality of life after acute myocardial infarction in Canada and the United States. N Engl J Med. 1994; 331:1130-5.