AT THE ESC CONGRESS 2016
ROME (FRONTLINE MEDICAL NEWS) – Radiation-induced aortic stenosis is associated with markedly worse long-term outcome after surgical aortic valve replacement than when the operation is performed in patients without a history of radiotherapy, Milind Y. Desai, MD, reported at the annual congress of the European Society of Cardiology.
Moreover, the Society of Thoracic Surgeons (STS) score isn’t good at risk-stratifying patients with radiation-induced aortic stenosis who are under consideration for surgical aortic valve replacement (SAVR).
“We probably need to develop a new score for these patients,” said Dr. Desai , a cardiologist at the Cleveland Clinic.
Radiation-induced heart disease is a late complication of thoracic radiotherapy. It’s particularly common in patients who got radiation for lymphomas or breast cancer. It can affect any cardiac structure, including the myocardium, pericardium, valves, coronary arteries, and the conduction system.
Aortic stenosis is the most common valvular manifestation, present in roughly 80% of patients with radiation-induced heart disease. At the Cleveland Clinic, the average time from radiotherapy to development of radiation-induced aortic stenosis (RIAS) is about 20 years. The condition is characterized by thickening of the junction between the base of the anterior mitral leaflet and aortic root, known as the aortomitral curtain, Dr. Desai explained.
He presented a retrospective observational cohort study involving 172 patients who underwent SAVR for RIAS and an equal number of SAVR patients with no such history. The groups were matched by age, sex, aortic valve area, and type and timing of SAVR. Of note, the group with RIAS had a mean preoperative STS score of 11, and the control group averaged a similar score of 10.
The key finding: During a mean follow-up of 6 years, the all-cause mortality rate was a hefty 48% in patients with RIAS, compared with just 7% in matched controls. Only about 5% of deaths in the group with RIAS were from recurrent malignancy. The low figure is not surprising given the average 20-year lag between radiotherapy and development of radiation-induced heart disease.
“In our experience, most of these patients develop a recurrent pleural effusion and nasty cardiopulmonary issues that result in their death,” according to Dr. Desai.
In a multivariate Cox proportional hazards analysis, a history of chest radiation therapy was by far the strongest predictor of all-cause mortality, conferring an 8.5-fold increase in risk.
The only other statistically significant predictor of mortality during follow-up in multivariate analysis was a high STS score, with an associated weak albeit statistically significant 1.15-fold increased risk. A total of 30 of 78 (39%) RIAS patients with an STS score below 4 died during follow-up, compared with none of 91 controls.
Thirty-four of 92 (37%) RIAS patients under age 65 died during follow-up, whereas none of 83 control SAVR patients did so.
Having coronary artery bypass surgery or other cardiac surgery at the time of SAVR was not associated with significantly increased risk of mortality compared with solo SAVR.
In-hospital outcomes were consistently worse after SAVR in the RIAS group. Half of the RIAS patients experienced in-hospital atrial fibrillation and 29% developed persistent atrial fibrillation, compared with 30% and 24% of controls. About 22% of RIAS patients were readmitted within 3 months after surgery, as were only 8% of controls. In-hospital mortality occurred in 2% of SAVR patients with RIAS; none of the matched controls did.
Dr. Desai reported having no financial interests relative to this study.