Embolization of IMA side branch for post-CABG ischemia.

The existence of a chest wall "steal" of blood away from the myocardium through patent internal mammary artery branches has been hypothesized as a cause of recurrent angina pectoris after coronary artery bypass grafting. Although some authors believe that such a steal is physiologically impossible because coronary flow occurs in diastole and chest wall flow in systole, we recently documented ischemia in the left anterior descending coronary artery distribution before embolization of a large left internal mammary artery first intercostal branch that had been left intact at the time of operation. After embolization of the branch, clinical and objective evidence of ischemia resolved.