The cause of death was not known for a substantial proportion of subjects in this study, but cardiopulmonary causes were implicated in at least half of the deaths among radiation-exposed patients. "Why this should be the case in a group of patients who received potentially life-preserving revascularization, valve, and other procedures is unknown at present," Dr. Wu and his associates said.
In addition, patients with radiation-related heart disease had longer hospital stays, were more likely to develop atrial fibrillation after surgery, were more likely to require pacemaker implantation after surgery, had higher rates of ventricular dysfunction and of valvular regurgitation following surgery, and had higher 30-day mortality.
The finding that radiation-exposed patients "remained in hospital for a considerable period after their surgery" suggests that the procedures and postoperative courses were complicated.
"Radiation patients frequently develop pulmonary complications as a result of open heart surgery, not the least of which are recurrent pleural effusions and severe restrictive lung disease. It is our experience that respiratory complications may significantly compromise function and survival in patients with extensive prior radiation," the researchers said.
"Additionally, the presence of myocardial disease either as a result of the underlying cardiac condition (potentially exacerbated by prior chemotherapy) or as a consequence of a restrictive-type cardiomyopathy produced by the effects of radiation may play a role in impaired survival and is not necessarily improved by valvular or revascularization surgery," they said.
The radiation-exposed patients’ poor long-term survival after conventional cardiac surgery indicates that other, nonsurgical treatments may be necessary for this complex patient population, they added.
No relevant financial conflicts were reported.