Endocardial Prevalence of Coronary Collaterals Becomes Transmurally More Uniform in a Human Heart with Left Ventricular Hypertrophy

Abstract

AimTo quantify and characterize coronary collaterals (CC) in human hearts.MethodsWe obtained one heart with left ventricular hypertrophy (LVH), and an old inferior posterolateral infarction (64 years, 595 g) and one normal heart without prior coronary artery disease (84 years, 330 g). The coronary arteries were filled with fluorescent replica material. Hearts were frozen, alternately cut and block‐face imaged using an imaging cryomicrotome (voxel size 32 μm). Collateral transmural distribution, connectivity and diameter were determined.ResultsThree times more collaterals were detected in the normal (n=4308) compared to the LVH heart (n=1272). In the normal heart, collaterals were mainly in the LV free wall (endo: 78%, mid: 14%, epi: 5%), whereas a more uniform distribution over the LV free wall (endo: 25%, mid: 12%, epi: 21%) and septum (endo: 27%, mid: 10%, epi: 2%) was found in the LVH heart. More intraCC (within major branches) than interCC (between major branches) were detected in the normal (4191 vs. 117) and LVH (1187 vs. 85) heart. InterCC were most prevalent between LCX‐LAD (99%) in the normal and between LCX‐LAD (62%) and LAD‐RCA (33%) in the LVH heart. Most intraCC were within the LAD and LCX territories in both hearts. The median CC diameter was larger in the LVH compared to the normal heart for both interCC (92.3 vs. 71.6 μm, p<0.001) and intraCC (81.88 vs. 60.4 μm, p<0.001).ConclusionsAs in healthy canine hearts, human hearts have abundant intra‐ and interCC collaterals. Transmural distribution was more homogeneous in LVH, with fewer but larger collaterals.