Effects of Radiotherapy in Coronary Artery Disease

This review describes the effects of radiotherapy (RT) on coronary artery disease, its mechanisms, and clinical and laboratory evidence and discusses ways to minimize radiation-induced coronary atherosclerosis.

Radiation-induced cardiac toxicity is known in patients undergoing thoracic RT. One of the damages occurs in the coronary arteries, with accelerated atherosclerosis manifesting decades later. There is clinical and laboratory evidence of coronary damage in retrospective studies, systematic reviews, and meta-analyses. Clinical studies have shown that RT cardiotoxicity occurs decades after radiation, regardless of chemotherapy, and may occur earlier in patients with pre-existing risk factors or disease. The pathogenesis of radiation-induced coronary artery disease is complex and multifactorial, including endothelial dysfunction, altered vascular tone, hemostatic imbalance, and inflammatory activation. Some factors are responsible, such as mean heart dose, RT chest site, patient position, techniques, and breathing maneuvers. There are approaches to reduce radiation-induced cardiac toxicity. Among them, besides the mentioned factors, metformin and anti-inflammatory agents can minimize coronary damage, with impact on morbidity and mortality.