The following are key points to remember from this state-of-the-art review on treatment modalities for radiation-induced aortic stenosis:

1. Among patients who receive radiation to the chest, 37-81% develop valvular heart disease. The effects of radiation are dose-dependent, and >30 Gy is considered a high dose of mediastinal radiation. Among patients who receive mediastinal radiation therapy for malignancies, the aortic valve is most commonly affected, as it is directly in line with the radiation beam. Women are disproportionately affected by radiation-induced aortic stenosis (AS), likely in part due to use of radiation treatment for breast cancer. Typically, the aortomitral continuity calcifies, with a 10- to 20-year latency period between radiation treatments and the manifestation of valvular disease.
2. Patients with a history of radiation to the chest are at high risk for open heart surgery. Calcification and fibrosis of blood vessels (including porcelain aorta), mediastinal adhesions, and radiation-induced pulmonary fibrosis can lead to intraoperative technical challenges and increased risk of postoperative complications. One study showed an observed-to-expected mortality ratio of 5 among patients undergoing surgical aortic valve replacement (SAVR) for radiation-induced AS, as compared with controls with no radiation history. Hence, a history of chest radiation is now included in the Society of Thoracic Surgeons (STS) risk score for surgical morbidity and mortality. Reoperation in patients with prior chest radiation carries an extremely high risk of mortality (17% in one study, as compared with 2.3% of non-irradiated patients).
3. Transcatheter aortic valve replacement (TAVR) is a promising alternative to SAVR for patients with radiation-induced AS. In a 2020 systematic review and meta-analysis including four studies, patients undergoing TAVR for radiation-induced AS had no significant difference in 30-day mortality as compared with controls, though they had higher 1-year mortality and greater risk of heart failure exacerbation.
4. One potential downside of TAVR is limited durability, especially in young cancer survivors. Long-term studies are needed to evaluate TAVR outcomes specifically among patients who have received mediastinal radiation.
5. Unusual complications of TAVR, such as ventricular septal defect and native aortic valve leaflet rupture, have been reported among patients with a history of radiation. These appear to be uncommon.
6. Four retrospective studies have compared outcomes of TAVR and SAVR among patients with radiation-induced AS. Three of these studies showed significantly lower mortality among patients undergoing TAVR, and the fourth study showed a trend toward decreased mortality with TAVR. TAVR was associated with lower rates of complications including postoperative atrial fibrillation and respiratory complications, though the rates of complete heart block and pacemaker insertion were lower among patients undergoing SAVR.
7. Choice of treatment modality for radiation-induced AS should be based on a multidisciplinary discussion, involving the primary cardiologist, interventional cardiologist, cardiac surgeon, and oncologist, as well as shared decision making with the patient.
8. The authors propose a decision-making algorithm for treatment of severe radiation-induced AS. Among patients who are at intermediate or high risk for surgery, TAVR is recommended if technically feasible. High-risk SAVR may be performed for patients with technical impediments to TAVR (including small aortic annulus size, short coronary ostium height, and unsuitable left ventricular outflow tract calcifications). For patients at low surgical risk who have concomitant coronary artery disease requiring revascularization and/or significant involvement of other valves, SAVR + coronary artery bypass grafting (CABG) and/or concomitant valve replacement are recommended. Patients at low surgical risk with isolated AS can be considered for TAVR if no technical impediments are present. Combined, staged, and hybrid procedures (such as off-pump CABG + TAVR) may be considered.
9. The International Cardio-Oncology Society recommends obtaining routine transthoracic echocardiograms in all patients prior to thoracic radiation and every 5 years thereafter to screen for radiation-induced valvulopathy.

Clinical Topics: Arrhythmias and Clinical EP, Cardiac Surgery, Cardio-Oncology, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Valvular Heart Disease, Atherosclerotic Disease (CAD/PAD), Atrial Fibrillation/Supraventricular Arrhythmias, Aortic Surgery, Cardiac Surgery and Arrhythmias, Cardiac Surgery and VHD, Interventions and Coronary Artery Disease, Interventions and Imaging, Interventions and Structural Heart Disease, Echocardiography/Ultrasound

Keywords: Aortic Valve Stenosis, Atrial Fibrillation, Breast Neoplasms, Cardiac Surgical Procedures, Cardiotoxicity, Coronary Artery Bypass, Coronary Artery Disease, Echocardiography, Fibrosis, Heart Valve Diseases, Morbidity, Myocardial Revascularization, Pacemaker, Artificial, Radiation, Reoperation, Risk, Transcatheter Aortic Valve Replacement, Treatment Outcome

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