Neither perioperative aspirin nor clonidine prevents MI

Myriad, and sometimes opposing, mechanisms contribute to perioperative MI, including excess bleeding, dramatic fluid shifts, unrelenting tachycardia, myocardial stress with fixed coronary obstruction, profound hypo- or hypertension, coronary plaque rupture, and coronary spasm, said Dr. Prashant Vaishnava and Dr. Kim A. Eagle.

So it shouldn’t be surprising that a medical therapy aimed at one of these mechanisms may actually augment a different mechanism, and end up raising MI risk. "Aspirin may reduce coronary thrombosis at the expense of excess bleeding; clonidine may reduce hypertensive swings only to be countered by clinically important hypotension," they noted.

On balance, the POISE-2 results provide cogent evidence against the use of either perioperative aspirin or clonidine.

Dr. Vaishnava and Dr. Eagle are at the Samuel and Jean A. Frankel Cardiovascular Center at the University of Michigan Health System, Ann Arbor. They reported no potential conflicts of interest. These remarks were taken from their editorial accompanying the POISE-2 trial reports (New Engl. J. Med. 2014 March 31 [doi:10.1056/NEJMe1402976]).