Cardiac amyloidosis in patients undergoing aortic valve replacement for aortic stenosis

Abstract

Abstract Background Transthyretin cardiac amyloidosis (ATTR) has been increasingly recognized in patients with degenerative aortic stenosis (AS). In some reports, the uptake of Tc-99m labeled bone radiotracers in cardiac amyloidosis has been documented. Tc-99m pyrophosphate (PYP) scintigraphy in the absence of evidence of a monoclonal gammopathy was diagnostic for transthyretin cardiac amyloidosis, providing a cost-effective and non-invasive technique with a specificity and positive predictive value of nearly 100%. We sought to determine the prevalence of ATTR as detected by the bone scan tracer among the patients with severe AS requiring surgical valve replacement. Methods We retrospectively analyzed clinical and echocardiographical data for 44 patients with severe AS requiring surgical valve replacement between Jan. 2009 and Dec. 2016. All eligible patients were offered Tc-99m PYP scintigraphy. Retention of Tc-99m PYP in the heart was assessed using both a semiquantitative visual score (range, 0 [no uptake] to 3 [uptake greater than bone]). Positive uptake was defined score 2 and 3. Results Myocardial deposition of Tc-99m PYP (Score 2–3) was identified in 4 of 44 patients (9%), all >70 years and 75% male. Patients with myocardial deposition of the tracer were older (78±8 years vs. 70±12 years), and had more mean interventricular septum thickness (18±3 mm vs. 14±5 mm). Both groups had at least ejection fraction and abnormal global longitudinal strain with no significant difference between groups. Pre-operative serum median NT-pro BNP level was similar between two groups, but post-operative improvement of NT-pro BNP was larger in non-deposition of the tracer group. During the post operative follow-up, survival was significantly worse if patients had amyloid deposition compared with no deposition subjects (25% vs. 7.5%). Conclusion Incidental transthyretin cardiac amyroidosis had a prevelance of 9% among patients undergoing surgical aortic valve replacement and was associated with a poor outcome. Funding Acknowledgement Type of funding source: None