After an acute MI, patients in whom coronary spasm can be triggered by acetylcholine provocation have a poorer prognosis, Japanese researchers report.

After an acute MI, patients in whom coronary spasm can be triggered by acetylcholine provocation have a poorer prognosis than their peers without this finding, Japanese researchers report.

Coronary spasm is known to play a role in the pathogenesis of acute MI and progressive atherosclerosis, Dr. Kohei Wakabayashi, from Showa University Fujigaoka Hospital in Yokohama, and colleagues explain. However, the prognostic importance of provoked coronary spasm in MI patients was unclear.

The present study, reported in the Journal of the American College of Cardiology for August 12, involved 240 consecutive patients who were evaluated with acetylcholine spasm provocation tests following acute MI. Overall, 174 patients had a positive test and 66 did not.

During a mean follow-up period of 43 months, 47.1 per cent of spasm patients experienced a major adverse cardiac event (MACE), including death, acute coronary syndrome, or revascularization. In the non-spasm group, the MACE rate was only 27.3 per cent (p = 0.0055).

Multivariate analysis showed that provoked coronary spasm was an independent predictor of poor outcomes following MI.

The key question at this point is whether spasm testing is useful in the management of patients with acute coronary syndromes, Dr. Carl J. Pepine, from the University of Florida College of Medicine in Gainesville, writes in a related editorial.

This question "would require an adequately powered, randomized study assessing the outcomes impact of a routine coronary artery spasm detection and management strategy in acute coronary syndrome compared with the prevailing strategy of very restricted attempts at coronary artery spasm detection and management," he points out.

J Am Coll Cardiol 2008;52:518-530