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(Circulation. 2007;116:2656-2657.)
© 2007 American Heart Association, Inc.

Editorial

Evaluating the Optimal Timing of Angiography

Landmark or off the Mark?

Sharon-Lise T. Normand, PhD

From the Department of Health Care Policy, Harvard Medical School, and the Department of Biostatistics, Harvard School of Public Health, Boston, Mass.

Correspondence to Sharon-Lise T. Normand, PhD, Department of Health Care Policy, Harvard Medical School, 180 Longwood Ave, Boston, MA 02115. E-mail Sharon@hcp.med.harvard.edu

Key Words: cardiovascular diseases • coronary angiography • data interpretation, statistical • outcome assessment • statistics

An extract of the first 250 words of the full text is provided, because this article has no abstract.

	Introduction

 
The study by Tricoci and colleagues¹ in the present issue of Circulation concludes that shortening the time from hospital admission to coronary angiography was associated with fewer ischemic outcomes with no increased bleeding. Although we know that use of an early invasive strategy in patients with non–ST-segment–elevation acute coronary syndromes is associated with improved outcomes, the optimal time to perform coronary angiography in those scheduled to receive an invasive strategy is unknown.

Article p 2669

The Tricoci et al¹ study capitalized on the clinical data collected as part of the Superior Yield of the New Strategy of Enoxaparin, Revascularization, and Glycoprotein IIb/IIIa Inhibitors (SYNERGY) trial² to study this question. Because the goal of the SYNERGY trial was to compare the outcomes of patients treated with enoxaparin versus unfractionated heparin, (1) patients were not randomized to different times to angiography (such as 6 hours, 6 to 12 hours, 12 to 18 hours, etc) after hospital arrival, and (2) some patients may have died or experienced an adverse event before receiving angiography. The authors adopted 2 different analytical strategies to address these issues: a landmark analysis³ and an inverse-probability–weighted approach.⁴ These 2 approaches differ in their basic assumptions and in the populations to which they apply.

	The Landmark Method

 
This method was proposed in the early 1980s in cancer studies in which many researchers had compared survival rates of treated patients whose tumors responded to a therapy to those of treated patients whose tumors did not respond. The erroneous conclusion often made from this comparison . . . [Full Text of this Article]

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