Introduction

CardioNerds (Dr. Patrick Azcarate, Dr. Teodora Donisan, and Amit Goyal) discuss Radiation-Associated Cardiovascular Disease (RACD) with Dr. Eric Yang, cardio-oncologist, assistant professor of medicine, and associate fellowship program director at UCLA. RACD is a consequence of radiation treatment for various mediastinal tumors (breast, lung, lymphoma). It is the second most common cause of morbidity and mortality in patients treated with mediastinal radiation for cancer. While novel techniques decrease radiation exposure during cancer treatment, the incidence is expected to increase because of historical practices and delayed onset of symptoms. The prevalence of RACD is difficult to estimate given under-recognition. Additionally, most of the data comes from patients treated with radiation techniques from decades ago. In this discussion we review every nook and cranny of RACD to help guide you the next time you see a patient with a history of chest radiation. Review this CardioNerds Case Report of radiation associated cardiovascular disease for more: Episode #169. Chest pain in a Young Man – “A Gray (Gy) Area” – UC San Diego. Audio editing by CardioNerds Academy Intern, student doctor Yousif Arif. This episode is supported by a grant from Pfizer Inc. This CardioNerds Cardio-Oncology series is a multi-institutional collaboration made possible by contributions of stellar fellow leads and expert faculty from several programs, led by series co-chairs, Dr. Giselle Suero Abreu, Dr. Dinu Balanescu, and Dr. Teodora Donisan.  Pearls • Notes • References • Production Team CardioNerds Cardio-Oncology PageCardioNerds Episode PageCardioNerds AcademyCardionerds Healy Honor Roll CardioNerds Journal ClubSubscribe to The Heartbeat Newsletter!Check out CardioNerds SWAG!Become a CardioNerds Patron! Pearls and Quotes - Radiation-Associated cardiovascular disease Due to the legacy effect, the incidence of RACD will continue to increase in the next few years. When treating patients with a history of mediastinal radiation, we should remember to ask: How much radiation was given? Could the heart have been exposed? Radiation can affect every part of the heart by causing coronary artery disease (CAD), valvulopathy, myocardial disease, conduction disease, and pericardial disease. Exposure to ~25-30 Gy or more significantly increases the risk but RACD can occur at lower doses. Try to delay surgery as much as possible and do all you can in one operation to avoid re-operation in the future. For revascularization, percutaneous coronary intervention (PCI) is typically preferred over coronary artery bypass grafting (CABG) but the choice should be individualized in consultation with a multidisciplinary heart team experienced in the management of RACD. In general, for aortic valve disease, transcatheter replacement is recommended over surgical aortic valve replacement. For mitral valve disease, surgical replacement is recommended over repair. Every decision should be made with a heart team approach and made unique to that specific patient. Show notes - Radiation-Associated cardiovascular disease Notes were drafted by Dr. Patrick Azkarate. 1. Understand the pathophysiology of RACD Ionizing radiation has the potential to damage DNA. Both normal cells and cancer cells get damaged, but cancer has less effective DNA repair mechanisms and therefore malignant cells are more vulnerable to radiation therapy. After radiation causes acute damage, this sets off an inflammatory cascade leading to myofibroblast activation, fibrosis and collagen deposition, and subsequent stiffening of the myocardium and vessels. 2. What may increase one’s risk of developing RACD? Young age (<50 years-old) at the time of radiation High cumulative dose (>30 Gy) or high dose of radiation fractions (>2 Gy/day) Anterior or left chest radiation (breast cancer, lung cancer, lymphoma)