Plaque problems.

This retrospective study of over 900 patients receiving breast radiation sought to determine if the dose to LAD plaques (when present) was a better predictor of MACE than (once again) mean heart dose. The rationale stems from in vitro models suggesting that radiation leads to unstable coronary artery plaques and subsequent cardiac events. Among these patients, 18% had a LAD plaque. They calculated MHD, left ventricle (LV) V5, mean LAD dose, and mean dose to the atherosclerotic plaque. Patients with a LAD plaque had a higher risk of MACE (11.7%) compared to those without a plaque (2.8%). In patients with a plaque, mean plaque dose was the factor most strongly associated with the risk of MACE. Each additional Gy mean dose to the plaque resulted in a 19.5% relative increase in the risk of MACE. In patients without plaques, the LV V5 was most strongly associated with MACE. | Bogaard, Int J Radiat Oncol Biol Phys 2021