Prevalence of cardiac amyloidosis in patients undergoing transcatheter edge-to edge mitral valve repair

Abstract

Abstract Introduction Cardiac amyloidosis (CA) is associated with severe aortic stenosis, however, its prevalence in patients with severe mitral regurgitation in elderly patients is unknown. Methods Patients scheduled for transcatheter edge-to edge mitral valve repair (TMVR) were prospectively screened for CA using 99m technetium-3,3-diphosphono-1,2-propanodicarboxylic acid (DPD) bone scintigraphy and subsequent serum as well as urine free light-chain quantification in case of a positive DPD scan, defined as visual cardiac update based on the Perugini grading scale. Results Out of 100 patients undergoing TMVR, 28 patients (28.0%) had a positive DPD-scan (DPD+). 14 patients (14.0%) showed Perugini grade I enhancement, 9 patients (9.0%) grade II enhancement, and in 5 patients (5.0%), grade III enhancement was present. 28 patients suffered from TTR and two from AL- amyloidosis (one patient had a combination of TTR and AL-amyloidosis). When compared to patients with a negative scan (DPD-), DPD+ patients presented with similar baseline characteristics such as age (DPD- vs DPD+ 76y/o vs 77y/o, p=0.44), gender (female; 62.7% vs 50.0%, p=0.25), coronary artery disease (59.7% vs 42.9%, p=0.13), previous valve surgery (25.4% vs 14.3%, p=0.24) and atrial fibrillation (68.7% vs 78.6%, p=0.33). Also, NYHA functional class and EuroScore II were similar (NYHA ≥ III; 85.1% vs 82.1%, p=0.72, and EuroScore II 9.9±9.8% vs 7.0±4.8%, p=0.21, respectively). On echocardiography, DPD+ patients presented with more pronounced left and right ventricular hypertrophy (interventricular septum: 15mm vs 13mm, p<0.01) but similar left ventricular ejection fraction (44.9% vs 42.3%, p=0.34). At 3-months after TMVR, DPD+ patients showed significant improvement in BNP serum levels when compared to DPD- patients (DPD+ vs DPD-: +315±2569pg/ml vs −2404±8696pg/ml, p=0.03), while NYHA functional class remained unchanged (NYHA improvement ≥1 class: 57.6% vs 50.0%, p=0.52) Conclusions In this single centre experience, CA was highly prevalent among elderly patients with severe mitral regurgitation scheduled for TMVR. TMVR in CA patients resulted in significant improvement of NT-pro BNP levels. Future studies need to clarify the prognostic relevance of CA in this specific patient population. Funding Acknowledgement Type of funding sources: None.