Preoperative NT-proBNP Predicts Midterm Outcome After Septal Myectomy

Mitral Valve Prolapse in Obstructive Hypertrophic Cardiomyopathy

Obstructive hypertrophic cardiomyopathy (oHCM) and mitral valve (MV) prolapse (MVP) are the 2 conditions which could cause symptomatic heart failure and sudden cardiac death. The clinical characteristics and surgical outcomes of patients with oHCM and MVP have not been well reported. From April 2012 to February 2018, 84 patients with oHCM (28 patients with MVP and 56 gender- and age-matched patients without MVP) who underwent septal myectomy at our institution were enrolled in this study. Information on clinical characteristics and outcomes was obtained from electronic medical records and follow-up surveys. Compared with those without MVP, patients with MVP were more symptomatic (New York Heart Association class III to IV; 96% vs 77%), more often moderate-to-severe mitral regurgitation (86% vs 48%), atrial fibrillation (39% vs 11%) and higher incidence of nonsustained ventricular tachycardia (44% vs 15%). Twenty (71%) had MV repair and 8 (29%) had MV replacement. Compared with patients without MVP, those with MVP had a longer postoperative hospital stay (10.9 ± 6.4 vs 7.8 ± 2.8 days). None of the 84 study patients died during hospital or follow-up. At the most recent echocardiographic evaluation, left ventricular outflow tract gradient significantly decreased from 69.7 ± 35.4 millimeters of mercury to 7.3 ± 5.1 millimeters of mercury and the degree of mitral valve regurgitation improved from grade 2.43 ± 0.69 to grade 0.5 ± 0.69. In conclusion, MVP occurs rarely in oHCM, and was related to atrial fibrillation, ventricular arrhythmia and mitral regurgitation. Mitral valve surgery in combination with myectomy is effective and safe for patients with oHCM and MVP, relieving substantially left ventricular outflow tract gradients and mitral regurgitation.

Metalloproteinases and Hypertrophic Cardiomyopathy: A Systematic Review

Hypertrophic cardiomyopathy (HCM) is a genetic condition determined by an altered collagen turnover of the extracellular matrix. Matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) are abnormally released in patients with HCM. The purpose of this systematic review was to thoroughly summarize and discuss the existing knowledge of MMPs profile in patients with HCM. All studies meeting the inclusion criteria (detailed data regarding MMPs in patients with HCM) were selected, after screening the literature from July 1975 to November 2022. Sixteen trials that enrolled a total of 892 participants were included. MMPs-particularly MMP2-levels were found higher in HCM patients compared to healthy subjects. MMPs were used as biomarkers after surgical and percutaneous treatments. Understanding the molecular processes that control the cardiac ECM's collagen turnover allows for a non-invasive evaluation of HCM patients through the monitoring of MMPs and TIMPs.

New Era: Mavacamten for Obstructive Hypertrophic Cardiomyopathy

Obstructive hypertrophic cardiomyopathy results from asymmetric septal hypertrophy, which eventually obstructs the outflow of the left ventricle. Obstructive hypertrophic cardiomyopathy is linked to mutations in genes that encode for sarcomere proteins, including actin, β-myosin heavy chain, titin, and troponin. The mutations lead to structural abnormalities in myocytes and myofibrils, causing conduction irregularities and abnormal force generation. Obstructive hypertrophic cardiomyopathy is a chronic disease that worsens over time, and patients become at higher risk of developing atrial fibrillation, heart failure, and stroke. Up until recently, there were no disease- specific medications for obstructive hypertrophic cardiomyopathy. Nevertheless, the US Food and Drug Administration approved mavacamten on April 28, 2022, for the treatment of symptomatic obstructive hypertrophic cardiomyopathy (New York Heart Association class II to III) in adults to improve functional capacity and symptoms. Its approval was based on data from EXPLORER- HCM and EXPLORER-LTE (NCT03723655). Mavacamten is a novel, first-in-class, orally active, allosteric inhibitor of cardiac myosin ATPase, which decreases the formation of actin- myosin cross-bridges, and thus, it reduces myocardial contractility, and it improves myocardial energetics. It represents a paradigm-shifting pharmacological treatment of obstructive hypertrophic cardiomyopathy. In this review, we describe its chemical and mechanistic aspects as well as its pharmacokinetics, adverse effects and warnings, potential drug-drug interactions, and contraindications.

Circulating Biomarkers in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy is the most common genetic heart disease. Biomarkers, molecules measurable in the blood, could inform the clinician by aiding in diagnosis, directing treatment, and predicting outcomes. We present an updated review of circulating biomarkers in hypertrophic cardiomyopathy representing key pathologic processes including wall stretch, myocardial necrosis, fibrosis, inflammation, hypertrophy, and endothelial dysfunction, in addition to their clinical significance.

Prognostic value of age-sex adjusted NT-proBNP ratio in obstructive hypertrophic cardiomyopathy

BACKGROUND

We sought to determine the incremental prognostic value of age-sex adjusted N-terminal prohormone brain natriuretic peptide (NT-pro BNP) ratio in obstructive hypertrophic cardiomyopathy (oHCM) patients.

METHODS

The study included 2119 consecutive oHCM patients (age 55 ± 13 years, 53% men, maximal LVOT ≥30 mmHg) evaluated between 6/2002-12/2018 with BNP or NT-pro BNP measured at baseline. NT-pro BNP ratio was calculated as: NT-proBNP/ upper limit of normal NT-proBNP derived from age-sex matched controls. Septal reduction therapy (SRT) during follow-up was recorded. Primary endpoint was death, need for cardiac transplantation or appropriate internal cardioverter defibrillator (ICD) discharge.

RESULTS

Median NT-proBNP ratio was 5.4 (IQR 2.1-12.3). Using spline analysis, log-transformed NT-pro BNP ratio of 2 (corresponding to NT-pro BNP ratio of 6) was the optimal value where primary endpoint hazards crossed 1; there were 966 patients with high and 1153 patients with low NT-pro BNP ratio. 1665 (79%) patients underwent SRT at 47 days (IQR 7-128 days). At 5.4 years of follow-up (IQR 2.8-9.2 years), the primary outcome occurred in 315 (15%) patients (deaths = 270). High NT-pro BNP ratio was associated with higher risk of primary outcome in unadjusted (30.1 vs. 17.2 events/1000 person-year, hazard ratio or (HR) 1.73, 1.37-2.17, P < 0.001) and adjusted analysis (aHR 1.69, 95% 1.19-2.38, P = 0.003) vs. low NT-pro BNP ratio. Even in asymptomatic patients, NT-pro BNP ratio remained associated with primary outcome (aHR 1.28, 95% CI 1.06-1.54, P = 0.01).

CONCLUSIONS

Age-sex adjusted NT-pro BNP ratio is independently associated with long-term outcomes in oHCM patients, including in a subgroup of asymptomatic patients.

Impact of type 2 diabetes mellitus on mid-term mortality for hypertrophic cardiomyopathy patients who underwent septal myectomy

Background

Type 2 diabetes mellitus is common in cardiovascular disease. It is associated with adverse clinical outcomes for patients who had undergone coronary artery bypass and valve operations. The aim of this study was to evaluate the impact of type 2 diabetes mellitus on the midterm outcomes of patients with hypertrophic cardiomyopathy who underwent septal myectomy.

Methods

We retrospectively analyzed the data of 67 hypertrophic cardiomyopathy patients with type 2 diabetes mellitus who underwent septal myectomy from two medical centers in China from 2011 to 2018. A propensity score–matched cohort of 134 patients without type 2 diabetes mellitus was also analyzed.

Results

During a median follow-up of 28.0 (interquartile range: 13.0–3.0) months, 9 patients died. The cause of death of all of these patients was cardiovascular, particularly sudden cardiac death in 3 patients. Patients with type 2 diabetes mellitus had a higher rate of sudden cardiac death (4.5% vs. 0.0%, p = 0.04). The Kaplan–Meier survival analysis revealed that the rates of predicted 3-year survival free from cardiovascular death (98.1% vs. 95.1%, p = 0.14) were similar between the two groups. However, the rates of predicted 3-year survival free from sudden cardiac death (100% vs. 96.7%, p = 0.01) were significantly higher in hypertrophic cardiomyopathy patients without type 2 diabetes mellitus than in those with type 2 diabetes mellitus. Furthermore, after adjustment for age and sex, only N-terminal pro-brain natriuretic peptide (hazards ratio: 1.002, 95% confidence interval: 1.000–1.005, p = 0.02) and glomerular filtration rate ≤ 80 ml/min (hazards ratio: 3.23, 95% confidence interval: 1.34–7.24, p = 0.047) were independent risk factors for hypertrophic cardiomyopathy patients with type 2 diabetes mellitus.

Conclusions

Hypertrophic cardiomyopathy patients with and without type 2 diabetes mellitus have similar 3-year cardiovascular mortality after septal myectomy. However, type 2 diabetes mellitus is associated with higher sudden cardiac death rate in these patients. In addition, N-terminal pro-brain natriuretic peptide and glomerular filtration rate ≤ 80 ml/min were independent risk factors among hypertrophic cardiomyopathy patients with type 2 diabetes mellitus.

Preoperative NT-proBNP Predicts Midterm Outcome After Septal Myectomy

Background

The prognostic value of N‐terminal pro–brain natriuretic peptide (NT‐proBNP) in patients with hypertrophic cardiomyopathy who underwent septal myectomy has not been well studied.

Methods and Results

We retrospectively evaluated NT‐proBNP levels in 758 patients (46.1±13.8 years; median follow‐up, 936 days) who underwent septal myectomy in our center between March 2011 and April 2018. The median NT‐proBNP level was 1450.5 (interquartile range 682.6‐2649.5) pg/mL. Overall, 22 (2.9%) patients died during follow‐up; of these, 86.4% were cardiovascular deaths. The 3‐year survival free from all‐cause mortality by tertile was 95.2% (95% CI 91.1% to 97.4%; NT‐proBNP >2080 pg/mL), 98.3% (95% CI 94.6% to 99.5%; NT‐proBNP, 947‐2080 pg/mL), and 99.2% (95% CI, 94.4% to 99.9%; NT‐proBNP <947 pg/mL). The 3‐year survival rate free from cardiovascular mortality by tertiles was 95.2% in the highest tertile, 98.8% in the middle tertile, and 99.2% in the lowest tertile. Cox regression analysis indicated that Ln(NT‐proBNP) was a significantly independent predictor of all‐cause mortality (hazard ratio 2.380, 95% CI 1.356‐4.178, P=0.003) and cardiovascular mortality (hazard ratio 2.788, 95% CI 1.450‐5.362, P=0.002). In addition, concomitant coronary artery bypass grafting for coronary artery disease was also an independent predictor of cardiovascular mortality (hazard ratio 5.178, 95% CI 1.597‐16.789, P=0.006).

Conclusions

Increased preoperative NT‐proBNP level is a strong predictor of midterm mortality in patients undergoing septal myectomy.