[The anatomical characteristics of the a. mammaria interna and their importance for the surgical results in aortocoronary bypass (a report on 2 clinical cases with large intercostal branches of the a. mammaria interna)].

This study attempted to determine the possibility for steal phenomenon after coronary surgery using internal mammary artery (IMA) as graft with unligated big side branches. The internal mammary artery (IMA) is considered to be the conduct of choice in coronary artery bypass grafting (CABH). The more IMA grafts are used, the more increases the significance of IMA anomalies and notably the large side branches for the surgical results. The importance of coronary subclavian steal syndrome is well known. We represent two clinical cases with big intercostal branches visualised at the postoperative coronary angiography, performed to evaluate the coronary and graft status cause of recurrent postoperative anginal pain. After cardiac catheterization we performed ECG stress test as follows: 1. A conventional stress test on treadmill (for control) and 2. Modified stress test loading the chest wall muscles in spine position. We expected to provoke and to evaluate steal phenomenon by the main IMA graft to the big lateral branches. At both of the patients on the arteriographic study IMA graft was patent and both had unusual large (> 50% of the IMA lumen) side branches, reducing the blood flow in the IMA graft. The modified stress test loading the chest wall muscles didn't provoke anginal pain at both patients. At the first (50 years old white male, CABG x 3-July 1193) it was evident non significant ST depression (< 2 mm) in V4-V% (suspicion of silent ischemia). At the second (70 years old white male, anterior MI-1990, GABG x 4-1992) the stress test was interrupted because of fatigue at the arm. No evident significant ecg changes. Despite we couldn't prove steal phenomenon through the angiographic study and the modified ECG stress test we suggest several logic.