Progression of Aortic Stenosis With Radiation
What are the differences in progression and outcomes in patients with moderate aortic stenosis (AS) due to mediastinal radiotherapy (XRT) compared to others with AS?
This study compared 81 patients with moderate XRT-associated AS and at least two echocardiograms at least 1 year apart in comparison to 162 patients with similar age, gender, and AS severity, but without XRT. The progression of AS by gradients and valve area, and outcomes including mortality and valve replacement, were compared between groups.
There were no significant differences between groups in measured clinical variables. There were no differences in baseline aortic valve area or mean gradient between groups, with no significant differences in progression over time. At follow-up (3.6 ± 2.0 years), patients with prior XRT had higher rates of valve replacement compared to others (80% vs. 50%, p < 0.01). At a mean follow-up of 6.6 ± 4.0 years, there was higher mortality in the XRT group (40% vs. 11%, p < 0.01).
Patients with moderate AS in the setting of XRT have similar rates of intermediate-term progression of AS compared to individuals without XRT. Patients with prior XRT are more likely to be treated with valve replacement and experience increased mortality.
This study demonstrates a similar rate of progression of AS in patients with versus without prior history of XRT during an intermediate-term follow-up, although it is not known whether differences in progression would be observed during a longer follow-up period. Also, it is not known how many individuals had a bicuspid aortic valve. Given the young mean age (61 years), it is possible that bicuspid aortic valves were present in a significant number of patients and could have been more prevalent in the control group, potentially impacting the rate of progression. Despite the lack of differences in progression during the study interval, patients with XRT had increased rates of valve replacement. The reasons for this difference are not clear; it is possible patients with XRT had earlier onset of symptoms, or there may be unmeasured differences between groups. The increased mortality in patients with prior XRT is consistent with prior studies of individuals undergoing cardiac surgery, and needs to be considered when evaluating these patients for aortic valve replacement. The effect of transcatheter aortic valve replacement on long-term outcomes in this population also needs to be investigated.
Keywords: Aortic Valve Stenosis, Cardiac Surgical Procedures, Diagnostic Imaging, Echocardiography, Heart Valve Diseases, Heart Valve Prosthesis, Outcome Assessment, Health Care, Radiation, Radiotherapy, Transcatheter Aortic Valve Replacement
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