Prognostic value of right ventricular global longitudinal strain in transthyretin amyloid cardiomyopathy

Background: This study was performed to investigate whether right ventricular global longitudinal strain (RV-GLS) provides prognostic information in patients with wild-type transthyretin amyloid cardiomyopathy (ATTRwt-CM).

Methods and results: Among 129 patients who were diagnosed with ATTRwt-CM at Kumamoto University Hospital from December 2002 to December 2019, 111 patients who had enough information for two-dimensional speckle tracking imaging were retrospectively analyzed. During a median follow-up of 615 days, 26 cardiovascular deaths occurred. Compared with patients in the non-event group, those in the cardiovascular death group were significantly older (81.1 ± 7.4 years vs. 78.2 ± 6.2 years, p = 0.009) and had significantly higher interventricular septal thickness in diastole (16.6 ± 3.1 mm vs. 15.3 ± 2.4 mm, p = 0.048), lower RV-GLS (10.9 ± 2.7% vs. 12.8 ± 3.5%, p = 0.010), and lower right ventricular free wall longitudinal strain (RVFWLS) (13.1 ± 3.3% vs. 15.5 ± 3.8%, p = 0.004). In the univariate Cox proportional hazard analysis, age, left atrial volume index (LAVI), RV-GLS, and RVFWLS were significantly associated with cardiovascular death [age, hazard ratio (HR), 1.10; 95% confidence interval (CI), 1.02-1.19, p = 0.010; LAVI, HR, 1.02; 95% CI, 1.00-1.03, p = 0.009; RV-GLS, HR, 0.86; 95% CI, 0.75-0.97, p = 0.017; RVFWLS, HR 0.89; 95% CI, 0.79-1.00; p = 0.041]. Multivariable Cox proportional hazard analysis showed RV-GLS was significantly and independently associated with cardiovascular death in patients with ATTRwt-CM (HR, 0.86; 95% CI, 0.74-0.99; p = 0.038). Receiver operating characteristic analysis showed that the area under the curve of RV-GLS for cardiovascular death was 0.668 and that the best cut-off value of RV-GLS was 11.59% (sensitivity, 69.2%; specificity, 63.5%). In the Kaplan-Meier analysis, patients with ATTRwt-CM who had low RV-GLS (<11.59%) had a significantly higher probability of total cardiovascular death (p = 0.004) and heart failure-related hospitalization (p = 0.013).

Conclusion: RV-GLS has significant prognostic value in patients with ATTRwt-CM and provides greater prognostic power than conventional echocardiographic findings.