Unveiling cardiac amyloidosis, its characteristics and outcomes among patients with mitral regurgitation undergoing transcatheter edge-to-edge mitral valve repair

Background

Mitral regurgitation (MR) and cardiac amyloidosis (CA) both primarily affect older patients. Data on co-existence and prognostic implications of MR and CA are currently lacking.

Purpose

We aimed to identify prevalence, clinical characteristics and outcomes of MR-CA compared to lone MR.

Methods

Consecutive patients undergoing transcatheter edge-to-edge repair (TEER) for MR were screened for concomitant CA at two Austrian centers using a multi-parametric approach including core-lab 99mTc-DPD bone scintigraphy and echocardiography, and immunoglobulin light-chain assessment. Transthyretin-CA (ATTR) was diagnosed by DPD (Perugini Grade-1: early infiltration; Grades-2/3: clinical CA) and absence of monoclonal protein, and light-chain-(AL)-CA via tissue biopsy. Mass spectroscopy was performed in case of conflicting immunohistochemical results. All-cause mortality and hospitalization for heart failure (HHF) served as composite endpoint.

Results

In total, 120 patients (76.9±8.1 years, 55.8% male) were recruited. Clinical CA was diagnosed in n=14 (11.7%; 12 ATTR, 1 AL, 1 combined ATTR/AL), and early amyloid infiltration in n=9 (7.5%). MR-CA had higher troponin levels, thicker left ventricular walls, and a higher prevalence of carpal tunnel syndrome and left anterior fascicular block compared to lone MR (all p<0.05). Independent predictors of MR-CA were increased posterior wall thickness, and presence of left anterior fascicular block on ECG. Procedural success (MR reduction ≥1 grade) and periprocedural complications of TEER were similar in MR-CA and lone MR (p for all=n.s.).

After a median of 1.7 years, 25.8% had experienced death and/or HHF. MR-CA had worse outcomes compared to lone MR with regard to the composite endpoint (HR 2.2, 95% confidence interval [95% CI] 1.0–4.7, p=0.039), driven by a 2.5-fold higher risk for HHF (HR 2.5, 95% CI 1.1–5.9), but comparable mortality (HR 1.6, 95% CI 0.4–6.1; Graphical abstract).

Conclusions

Dual pathology of MR-CA is common in elderly MR patients undergoing TEER, and has worse post-interventional outcomes compared to lone MR. Given technical feasibility of TEER in MR-CA, valvular repair should be considered as an option to improve forward volume in a state with typically low output. Future studies should evaluate the prognostic benefits of TEER and CA-specific treatment in MR-CA.

Funding Acknowledgement

Type of funding sources: None.

MicroRNA Let-7 targets AMPK and impairs hepatic lipid metabolism in offspring of maternal obese pregnancies

Nutritional status during gestation may lead to a phenomenon known as metabolic programming, which can be triggered by epigenetic mechanisms. The Let-7 family of microRNAs were one of the first to be discovered, and are closely related to metabolic processes. Bioinformatic analysis revealed that Prkaa2, the gene that encodes AMPK α2, is a predicted target of Let-7. Here we aimed to investigate whether Let-7 has a role in AMPKα2 levels in the NAFLD development in the offspring programmed by maternal obesity. Let-7 levels were upregulated in the liver of newborn mice from obese dams, while the levels of Prkaa2 were downregulated. Let-7 levels strongly correlated with serum glucose, insulin and NEFA, and in vitro treatment of AML12 with glucose and NEFA lead to higher Let-7 expression. Transfection of Let-7a mimic lead to downregulation of AMPKα2 levels, while the transfection with Let-7a inhibitor impaired both NEFA-mediated reduction of Prkaa2 levels and the fat accumulation driven by NEFA. The transfection of Let-7a inhibitor in ex-vivo liver slices from the offspring of obese dams restored phospho-AMPKα2 levels. In summary, Let-7a appears to regulate hepatic AMPKα2 protein levels and lead to the early hepatic metabolic disturbances in the offspring of obese dams.