CORONARY COLLATERAL CIRCULATION IN THE TRANSPLANTED HEART

Background. The concept that coronary collateral (CC) circulation can develop in cardiac transplant recipients (CTR) is controversial. Indee d, a decreased occurrence or CC in CTR has been previously reported. M ethods and Results. We reviewed 102 coronary angiograms in 73 CTR to e valuate the presence and significance of CC in denervated human hearts . These angiograms were compared with angiograms of 70 nontransplanted patients. Twenty-six CTR who had undergone at least two coronary angi ograms, thus allowing comparative evaluations, form the basis for this study. Angiograms were analyzed using a modification of CC classifica tion (Rentrop et al) from grade 0 for complete absence to grade 4 repr esenting mature collateral with clear filling of epicardial vessels. C oronary artery disease was classified according to the scheme reported by Gao et al. For the purpose of this study, all type A lesions were grouped as large vessel disease (LVD), and types B1, B2, and C were co llectively grouped as small vessel (epicardial) disease (SVD). The pre sence of CC circulation in all 73 CTR was grade 0, 7 (10%); grade 1, 4 1 (56%); grade 2, 33 (45%); grade 3, 30 (41%); and grade 4, 5 (7%). Ho wever, in control nontransplanted subjects grades 0, 1, 2, 3, and 4 we re found in 47 (67%), 22 (31%), 4 (6%), 11 (15%), and 16 (20%) patient s, respectively. The presence of mature collaterals (grade 4) in both groups were associated with type A lesions and was frequent in nontran splanted hearts. In contrast, grade 2 and grade 3 vascular channels pr obably representing CC with ''myocardial blush'' was more frequent in CTR and was mostly associated with small vessel coronary arteriopathy. Conclusions. These results suggest the presence of atypical CC in pat ients with cardiac allograft arteriopathy. It is speculated that this atypical form of CC with ''blush pattern'' may represent an angiogenic response to microvascular ischemia due to allograft coronary arteriop athy.