August 15th, 2013
Remote Ischemic Preconditioning Beneficial Before CABG
For several decades cardiologists have been intrigued by the concept of ischemic preconditioning. A small body of research has consistently found that brief episodes of ischemia appeared to somehow prepare the body to better handle a major episode of ischemia. Now a new study from Germany holds out the promise that deliberate ischemic preconditioning prior to bypass surgery might prevent ischemic injury caused by the surgery and may even improve long-term survival. But the investigators themselves say that the results need to be confirmed in a larger study.
Matthias Thielman and colleagues randomized 329 patients scheduled for elective CABG surgery at the West-German Heart Center in Essen, Germany to remote ischemic preconditoning or no preconditioning. Patients in the treatment group underwent three cycles of ischemic preconditioning, consisting of inflation of a blood pressure cuff for 5 minutes, followed by a 5-minute period of reperfusion.
Patients in the preconditioning group had significantly less cardiac damage than did controls in the first 3 days following surgery: the area under the curve for release of cardiac troponin I was 17% lower (CI 3-30%) in the treatment group (266 ng/ml) compared with the control group (321 ng/ml). This short-term difference appeared to result in long-term clinical benefits, yielding significant reductions in mortality and myocardial infarction at 1 year.
“The results of our study are very encouraging that remote ischemic preconditioning not only reduces heart muscle injury but also improves long-term health outcomes for heart bypass patients, and we hope that these benefits will be confirmed in larger prospective studies which are currently taking place” said Gerd Heusch, the senior author of the study, in a press release.
In an accompanying editorial, Nathan Mewton and Michel Ovize write that the “exciting findings… need to be supported by strong experimental evidence and elucidation of the mechanisms underlying the effects of remote conditioning.” The results also need to be tested in large phase 3 studies, they write, such as the ERICCA trial and the RIPHeart-Study which are now underway.