Unveiling Cardiac Amyloidosis, its Characteristics, and Outcomes Among Patients With MR Undergoing Transcatheter Edge-to-Edge MV Repair

Prevalence and clinical outcomes of isolated or combined moderate to severe mitral and tricuspid regurgitation in patients with cardiac amyloidosis

AIMS

Evidence on the epidemiology and prognostic significance of mitral regurgitation (MR) and tricuspid regurgitation (TR) in patients with cardiac amyloidosis (CA) is scarce.

METHODS AND RESULTS

Overall, 538 patients with either transthyretin (ATTR, n = 359) or immunoglobulin light-chain (AL, n = 179) CA were included at three Italian referral centres. Patients were stratified according to isolated or combined moderate/severe MR and TR. Overall, 240 patients (44.6%) had no significant MR/TR, 112 (20.8%) isolated MR, 66 (12.3%) isolated TR, and 120 (22.3%) combined MR/TR. The most common aetiologies were atrial functional MR, followed by primary infiltrative MR, and secondary TR due to right ventricular (RV) overload followed by atrial functional TR. Patients with isolated or combined MR/TR had a more frequent history of heart failure (HF) hospitalization and atrial fibrillation, worse symptoms, and higher levels of NT-proBNP as compared to those without MR/TR. They also presented more severe atrial enlargement, atrial peak longitudinal strain impairment, left ventricular (LV) and RV systolic dysfunction, and higher pulmonary artery systolic pressures. TR carried the most advanced features. After adjustment for age, sex, CA subtypes, laboratory, and echocardiographic markers of CA severity, isolated TR and combined MR/TR were independently associated with an increased risk of all-cause death or worsening HF events, compared to no significant MR/TR [adjusted HR 2.75 (1.78-4.24) and 2.31 (1.44-3.70), respectively].

CONCLUSION

In a large cohort of patients with CA, MR, and TR were common. Isolated TR and combined MR/TR were associated with worse prognosis regardless of CA aetiology, LV, and RV function, with TR carrying the highest risk.

Prevalence of valvular heart disease in cardiac amyloidosis and impact on survival

BACKGROUND

Limited data exists on the prognostic impact of valvular heart disease in cardiac amyloidosis (CA). We therefore sought to define the prevalence of valvular disease in patients with CA and assess the effects of significant valve disease on survival.

METHODS

This multi-center retrospective cohort study included consecutive patients with confirmed transthyretin (TTR) or light chain (AL) amyloidosis. Echocardiographic data closest to the date of amyloid diagnosis was reviewed, and severity was graded according to ASE guidelines. Kaplan-Meier survival analysis was performed to compare survival between patients with moderate or greater valve disease against those with mild or less disease.

RESULTS

We included 345 patients (median age 76 years; 73 % men; 110 AL, 235TTR). The median survival for the total patient cohort with cardiac amyloidosis was 2.92 years, with 30 % of patients surviving at five years after their diagnosis. Median survival comparing AL vs ATTR was 2.58 years vs 2.82 years (p = 0.67) The most common valvular abnormalities in the total cohort were mitral (62 %) and tricuspid (66 %).regurgitation There was a statistically significant difference in median survival between patients with no or mild MR compared to those with moderate or severe MR (2.92 years vs 3.35 years, p = 0.0047) (Fig. 5). There was a statistically significant difference in median survival in patients with no or mild TR compared to those with moderate or severe TR (3.35 years vs 2.3 years, p = 0.015).

CONCLUSION

Our study demonstrates a significant prevalence of mitral and tricuspid regurgitation in CA, with patients with moderate to severe MR and TR having a poorer prognosis.

Valvular heart disease in patients with cardiac amyloidosis

Cardiac amyloidosis (CA) is an underdiagnosed condition caused by the deposition of misfolded proteins, namely immunoglobulin light chains and transthyretin, in the extracellular spaces of the heart. Any cardiovascular structure can be affected by amyloid infiltration, including the valves. Amyloid accumulation within the cardiac valves may lead to their structural and functional impairment, with a profound impact on patients' prognosis and quality of life. The most common forms of valvular disease in CA are aortic stenosis (AS), mitral regurgitation (MR), and tricuspid regurgitation (TR). CA and AS share similar risk factors, disease mechanisms, and remodeling patterns, which make their diagnosis particularly challenging. Patients with both CA and AS experience worse outcomes than CA or AS alone, and transcatheter aortic valve replacement may represent a useful therapeutic strategy in this population. Data on MR and TR are quite limited and mainly coming from case reports or small series. This review paper will summarize our current understanding on the epidemiology, disease mechanisms, echocardiographic features, clinical implications, and therapeutic options of AS, MR, and TR in patients with CA.

Valvular heart disease and cardiomyopathy: reappraisal of their interplay

Cardiomyopathies and valvular heart diseases are typically considered distinct diagnostic categories with dedicated guidelines for their management. However, the interplay between these conditions is increasingly being recognized and they frequently coexist, as in the paradigmatic examples of dilated cardiomyopathy and hypertrophic cardiomyopathy, which are often complicated by the occurrence of mitral regurgitation. Moreover, cardiomyopathies and valvular heart diseases can have a shared aetiology because several genetic or acquired diseases can affect both the cardiac valves and the myocardium. In addition, the association between cardiomyopathies and valvular heart diseases has important prognostic and therapeutic implications. Therefore, a better understanding of their shared pathophysiological mechanisms, as well as of the prevalence and predisposing factors to their association, might lead to a different approach in the risk stratification and management of these diseases. In this Review, we discuss the different scenarios in which valvular heart diseases and cardiomyopathies coexist, highlighting the need for an improved classification and clustering of these diseases with potential repercussions in the clinical management and, particularly, personalized therapeutic approaches.

Cardiac Amyloidosis and Valvular Heart Disease

Growing interest has accrued in the co-existence of cardiac amyloidosis and valvular heart disease. Amyloid infiltration from either transthyretin (ATTR) or of light chain (AL) origin may affect any structure of the heart, including the valves. The recent literature has mainly focused on aortic stenosis and cardiac amyloidosis, improving our understanding of the epidemiology, diagnosis, treatment and prognosis of this dual pathology. Despite being of high clinical relevance, data on mitral/tricuspid regurgitation and cardiac amyloidosis are rather scarce and mostly limited to case reports and small cases series. It is the aim of this review article to summarize the current evidence of concomitant valvular heart disease and cardiac amyloidosis by including studies on epidemiology, diagnostic approaches, screening possibilities, therapeutic management, and prognostic implications.

A case report of transcatheter repair of severe functional mitral regurgitation in cardiac amyloidosis

Background

Transcatheter therapy has become an alternative for functional mitral regurgitation (FMR) in patients at high surgical risk. However, the intervention of FMR in cardiac amyloidosis (CA) with transcatheter edge-to-edge repair (TEER) is controversial due to the potential risk of left atrial pressure (LAP) elevation.

Case summary

An 83-year-old woman with repeated heart failure (HF) and severe mitral regurgitation (MR) was referred to our centre for TEER. Pre-procedural transthoracic echocardiography (TTE) and transoesophageal echocardiography (TOE) confirmed the degree of MR and a functional aetiology. A peculiar LAP increase in this patient occurred immediately after successful TEER clip implantation and her n-terminal prohormone of brain natriuretic peptide significantly increased post-operatively. The diagnosis of CA was suspected and was subsequently established through endomyocardial biopsy. Aggressive anti-HF therapy was initiated and the patient was discharged after her HF symptoms were relieved. At 6-month follow-up, the patient was still alive and no episode of acute HF was experienced.

Discussion

Severe functional MR in CA treated with TEER has the potential risk of increasing LAP. During the short-term follow-up, TEER appears beneficial for left heart function (reduction of MR) but harmful for right heart function (increase of LAP). CA patients with severe FMR should be carefully evaluated about the benefits and potential harm of TEER intervention.