Different mechanisms of mitral regurgitation in hypertrophic cardiomyopathy: A clinical case and literature review

Unique Aspects of Hypertrophic Cardiomyopathy in Children

Hypertrophic cardiomyopathy (HCM) is a primary heart muscle disease characterized by left ventricular hypertrophy that can be asymptomatic or with presentations that vary from left ventricular outflow tract obstruction, heart failure from diastolic dysfunction, arrhythmias, and/or sudden cardiac death. Children younger than 1 year of age tend to have worse outcomes and often have HCM secondary to inborn errors of metabolism or syndromes such as RASopathies. For children who survive or are diagnosed after 1 year of age, HCM outcomes are often favourable and similar to those seen in adults. This is because of sudden cardiac death risk stratification and medical and surgical innovations. Genetic testing and timely cardiac screening are paving the way for disease-modifying treatment as gene-specific therapies are being developed.

Comparing long-term outcomes of septal myectomy and mitral valve replacement in hypertrophic cardiomyopathy patients: A retrospective cohort study in Iran

Background

Hypertrophic cardiomyopathy (HCM) affects millions of individuals worldwide. In severe cases, it can cause life-threatening conditions such as left ventricular outflow tract (LVOT) obstruction, mitral regurgitation (MR), and sudden cardiac death, making surgical treatment necessary. This study aimed to report the long-term outcomes of HCM patients undergoing septal myectomy or mitral valve replacement (MVR) and compare the results between different types of surgeries.

Methods

This was a retrospective cohort study on HCM patients who underwent surgical treatment in an Iranian referral center between 2005 and 2021. Patients were divided into three groups according to the type of surgery received: septal myectomy, MVR, or a combination of both surgeries. Patient characteristics, surgical and echocardiographic features, and in-hospital and long-term outcomes were reported and compared between the three groups.

Results

A total of 102 patients with an average age of 53.3 ± 16.9 were included. Twenty-six patients had septal myectomy, 23 had MVR, and 53 had combined septal myectomy and MVR surgery. All surgeries were associated with a significant reduction in interventricular septum thickness and LVOT gradients. After a median of 6.8-year follow-up time, patients with an isolated septal myectomy had significantly lower mortality and major adverse cardiac and cerebrovascular events rates than the other groups.

Conclusion

Isolated septal myectomy showed better long-term survival rates and can correct HCM-related MR, while MVR should be preserved only for intrinsic valve defects. More extensive studies are needed to confirm these findings and achieve a comprehensive guideline on surgical treatment of HCM.

Prognostic Value of Mitral Regurgitation in Patients with Primary Hypertrophic Cardiomyopathy

Background and Objectives: Mitral valve pathology and mitral regurgitation (MR) are very common in patients with hypertrophic cardiomyopathy (HCM), and the evaluation of mitral valve anatomy and degree of MR is important in patients with HCM. The aim of our study was to examine the potential influence of moderate or moderately severe MR on the prognosis, clinical presentation, and structural characteristics of HCM patients. Materials and Methods: A prospective study examined 176 patients diagnosed with primary asymmetric HCM. According to the severity of the MR, the patients were divided into two groups: Group 1 (n = 116) with no/trace or mild MR and Group 2 (n = 60) with moderate or moderately severe MR. All patients had clinical and echocardiographic examinations, as well as a 24 h Holter ECG. Results: Group 2 had significantly more often the presence of the obstructive type of HCM (p < 0.001), syncope (p = 0.030), NYHA II class (p < 0.001), and atrial fibrillation (p = 0.023). Also, Group 2 had an enlarged left atrial dimension (p < 0.001), left atrial volume index (p < 0.001), and indirectly measured systolic pressure in the right ventricle (p < 0.001). Patients with a higher grade of MR had a significantly higher E/e' (p < 0.001) and, as a result, higher values of Nt pro BNP values (p < 0.001) compared to Group 1. Kaplan-Meier analysis demonstrated that the event-free survival rate during a median follow-up of 88 (IQR 40-112) months was significantly higher in Group 1 compared to Group 2 (84% vs. 45% at 8 years; log-rank 20.4, p < 0.001). After adjustment for relevant confounders, the presence of moderate or moderately severe MR remained as an independent predictor of adverse outcomes (HR 2.788; 95% CI 1.221-6.364, p = 0.015). Conclusions: The presence of moderate or moderately severe MR was associated with unfavorable long-term outcomes in HCM patients.

Mitral Valve in Obstructive Hypertrophic Cardiomyopathy: Abnormalities, Management and Controversies

Obstructive hypertrophic cardiomyopathy (obstructive HCM) is a hereditary disease characterized by septal hypertrophy and dynamic left ventricular outflow tract (LVOT) obstruction. Other than septal hypertrophy, mitral valve abnormalities are also quite common in patients with obstructive HCM, which may contribute to systolic anterior motion (SAM) of the mitral valve and LVOT obstruction. Surgical myectomy is the standard treatment to achieve anatomic correction of obstructive HCM, but controversies remain on whether and how the mitral valve procedures should be performed at the same time. In this review, we first described the mitral valve abnormalities in patients with obstructive HCM and their surgical corrections, we then explained the controversies based on current clinical studies, and we finally made a brief introduction on our surgical strategy and results.