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To the Editor: In their study of primary percutaneous coronary intervention (PCI) vs thrombolysis, Dr Stenestrand and colleagues¹ reported long-term outcomes among patients presenting with ST-segment elevation myocardial infarction (STEMI) in Sweden between 1999 and 2004.¹ They documented divergent outcomes stratified by initial reperfusion strategy. We would like to offer a different interpretation of the data.

Observational cohort studies have serious limitations in efficacy assessment because therapies are not determined randomly but in response to patient characteristics. Multivariable analyses take into account measured baseline variables but do not substitute for randomization. In this study, there are important differences in baseline clinical characteristics of the participants. Patients selected for primary PCI were younger, more often male, and less likely to have a history of heart failure; a significantly greater proportion was in Killip Class I. In addition, patients in each group were managed differently following selection of initial reperfusion. Only about . . . [Full Text of this Article]

Charanjit S. Rihal, MD
rihal@mayo.edu

Allan S. Jaffe, MD; David R. Holmes, Jr, MD; Henry H. Ting, MD; Bernard J. Gersh, MD; Malcolm R. Bell, MBBS
Mayo Clinic
Rochester, Minn