Characteristics of Patients with Patent versus Closed Left Internal Thoracic Artery Grafts before Redo Revascularization

Abstract

BACKGROUND: The aim of this study was to examine the impact of internal thoracic artery (ITA) graft patency on clinical course between initial and redo coronary artery bypass grafting (CABG). METHODS: 82 patients out of 553 redo CABG between 1990 and 1999 underwent ITA grafting to the left anterior descending artery (LAD) and vein grafting to other vessels at initial revascularization. At reoperation 54 patients (group I) showed a patent ITA, while 28 patients (group II) showed ITA occlusion. All patients underwent coronary angiography prior to initial and redo CABG. RESULTS: Absence of angina after initial CABG and time to redo operation was longer in group I (I vs. II: 5.1 ± 3.3 vs. 3.4 ± 3.6 years, p = 0.01; 6.0 ± 3.2 vs. 3.9 ± 3.6 years, p = 0.03; respectively). The incidence of myocardial infarction (MI) in the lateral/posterior myocardium was higher in group I (I vs. II: 38.9 % vs. 14.3 %; p = 0.021). MI rate of the anterior wall was comparable between both groups. Rate of interventional revascularization between operation was significantly lower in group I (I vs. I: 11.1 % vs. 32.1 %; p = 0.019). The rate of stenoses in the circumflex coronary artery (RCX) and the right coronary artery (RCA) increased significantly in group I compared to group II (p = 0.002 for RCX of 80–95 %; p = 0.034 for RCX > 95 %; p = 0.047 for RCA > 95 %). The number of occluded vein grafts to RCX and RCA was higher in group I (I vs. II: 48 % vs. 22 %, p = 0.028; 50 % vs. 17 %, p = 0.023; respectively). CONCLUSIONS: The angina-free interval after initial CABG between operations is longer in patients with patent ITA. However, the increase of lesions number in native vessels as well as in vein grafts is significantly higher in RCX and RCA systems in such patients due to a longer period between operations compared to patients with closed ITA. Hence, the risk for MI in the lateral/posterior myocardium in RCX/RCA territories is higher, which remains undetected in many cases because of sufficient perfusion of the anterior wall by patent ITA.