Increased aorto-mitral curtain thickness independently predicts mortality in patients with radiation-associated cardiac disease undergoing cardiac surgery

Abstract

Background: Thoracic radiation leads to radiation-associated cardiac disease (RACD), associated with substantial cardiac morbidity and mortality, often requiring complex cardiothoracic surgery. In patients with RACD, along with valvular lesions, the aorto-mitral curtain (AMC, junction between base of anterior mitral leaflet and aortic root) thickness is increased on transthoracic echocardiography. We sought to identify clinical and transthoracic echocardiography predictors of long-term mortality in patients with RACD.

Methods: We studied 173 patients with RACD (75% women, 63±14 years, 53% with breast cancer, 27% with Hodgkin lymphoma; mean time from radiation, 18±12 years), who underwent cardiothoracic surgery (26% redo) between 2000 and 2003. Clinical, transthoracic echocardiography (along with AMC), and surgical variables were recorded. Preoperative EuroSCORE and all-cause mortality were recorded.

Results: Mean left ventricular ejection fraction, right systolic ventricular pressure, and AMC thickness were 0.49±0.13, 41±15 mm Hg, and 0.54±0.2 cm, respectively. Fifty-one percent of patients had II+ mitral regurgitation or greater, 29% patients had II+ aortic regurgitation or greater, 23% patients had severe aortic stenosis, and 34% patients had II+ tricuspid regurgitation or greater. In 7.6±3 years of follow-up, there were 95 (55%) deaths, with a 30-day mortality rate of only 7 (4%). Absence of β-blockers (hazard ratio, 0.49; 95% confidence interval, 0.31 to 0.79), aspirin (hazard ratio, 0.53; 95% confidence interval, 0.33 to 0.84), higher EuroSCORE (hazard ratio, 1.11; 95% confidence interval, 1.02 to 1.21), and greater AMC thickness (hazard ratio, 5.75; 95% confidence interval, 1.57 to 21.03; all p<0.01) independently predicted mortality. Aorto-mitral curtain thickness of at least 0.6 cm was associated with significantly increased mortality.

Conclusions: Patients with RACD undergoing cardiothoracic surgery have high long-term mortality, which is independently predicted by AMC thickness, a higher preoperative risk score, and lack of cardioprotective medications.