WHAT THIS STUDY ADDS:

• Left ventricular function and the culprit lesion help predict one-year outcome in post-MI patients with cardiogenic shock.

EVANSTON, ILL—In 1999, the SHOCK (SHould we emergently revascularize Occluded Coronaries for cardiogenic shocK) trial reported that emergency revascularization improves survival in patients with cardiogenic shock, saving about 13 lives per 100 patients treated.[1] Recently, the SHOCK investigators reexamined their data to identify factors that could help predict one-year survival in patients with cardiogenic shock. Two were found: left ventricular function and the culprit vessel.[2]

The SHOCK trial, which was conducted in 36 centers worldwide, involved 302 patients who were randomized to receive emergency revascularization (ie, angioplasty or bypass surgery as soon as possible) or initial medical stabilization with thrombolytic agents. Coronary angiography was performed in 147 of the 152 patients in the revascularization group and in 100 of the 150 patients initially given medical stabilization.

LVEF, CULPRIT VESSEL, AND SURVIVAL

Angiography was not performed in five of the patients randomized to emergency revascularization and in 45 of those assigned to medical treatment because the patients died before the procedure could be undertaken. Among those in whom the procedure was performed, angiographic findings were similar: In both groups, nearly two thirds of the patients had disease involving three vessels; their mean left ventricular ejection fraction (LVEF) was about 30%, and their degree of mitral regurgitation was about 1.2.

The left anterior descending artery was identified as the culprit vessel in 49% of the patients. In 29%, the right coronary artery was implicated.

One-year survival was 47% in the revascularization group and 34% in the medical group. Disease severity was significantly correlated with one-year survival in the medical stabilization group only; in these patients, the hazard ratio for death per diseased vessel was 2.59.

LVEF was highly correlated with one-year survival in all patients, independent of group assignment. For every five-unit increase in baseline ejection fraction, the odds of dying within one year were reduced by almost one third. Multivariate analysis of patients who had undergone left ventriculography showed that LVEF decreased progressively as number of diseased arteries increased.

The site of the disease also predicted outcome in both groups. Survival was 68% when the right coronary artery was the culprit lesion but only 14% when a saphenous vein graft was blocked.

NEED FOR ANGIOGRAPHY AND REVASCULARIZATION

“Angiography should be performed in all patients,” said primary author Timothy A. Sanborn, MD, who is Head of the Division of Cardiology at Evanston Northwestern Healthcare. Not only does it identify factors that help predict outcome, but it allows rapid revascularization with angioplasty or bypass surgery. “In many institutions, however, angiography may not be used as often as it should.”

Dr. Sanborn, who is also a Professor of Medicine at Northwestern University’s Feinberg School of Medicine in Chicago, noted that the SHOCK trial has helped revolutionize the treatment of patients with cardiogenic shock. Previously, he said, the standard procedure was to stabilize the patient first and then consider angiography and revascularization. As a result of the SHOCK trial, he observed, physicians “are much more aggressive when treating cardiogenic shock.”

—Gale Jurasek

References
1. Hochman JS, Sleeper LA, Webb JG, et al, for the SHOCK Investigators. Early revascularization in acute myocardial infarction complicated by cardiogenic shock. N Engl J Med. 1999;341:625-634.
2. Sanborn TA, Sleeper LA, Webb JG, et al for the SHOCK Investigators. Correlates of one-year survival in patients with cardiogenic shock complicating acute myocardial infarction: angiographic findings from the SHOCK trial. J Am Coll Cardiol. 2003;42:1373-1379.

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