Effects of surgical septal myectomy on survival in patients with hypertrophic obstructive cardiomyopathy

The triglyceride-glucose index as a potential protective factor for hypertrophic obstructive cardiomyopathy without diabetes: evidence from a two-center study

OBJECTIVE

This study aimed to investigate the relationship between the TyG (Triglyceride-glucose index) and the prognosis of patients with HOCM (hypertrophic obstructive cardiomyopathy) without diabetes.

RESEARCH DESIGN AND METHODS

A total of 713 eligible patients with HOCM were enrolled in this study and divided into two groups based on treatment: an invasive treatment group (n = 461) and a non-invasive treatment group (n = 252). The patients in both two groups were then divided into three groups based on their TyG index levels. The primary endpoints of this study were Cardiogenic death during long-term follow-up. Kaplan-Meier analysis was used to study the cumulative survival of different groups. Restricted cubic spline was used to model nonlinear relationships between the TyG index and primary endpoints. Myocardial perfusion imaging/Myocardial metabolic imaging examinations were performed to assess glucose metabolism in the ventricular septum of the HOCM patients.

RESULTS

The follow-up time of this study was 41.47 ± 17.63 months. The results showed that patients with higher TyG index levels had better clinical outcomes (HR, 0.215; 95% CI 0.051,0.902; P = 0.036, invasive treatment group; HR, 0.179; 95% CI 0.063,0.508; P = 0.001, non-invasive treatment group). Further analysis showed that glucose metabolism in the ventricular septum was enhanced in HOCM patients.

CONCLUSIONS

The findings of this study suggest that the TyG index may serve as a potential protective factor for patients with HOCM without diabetes. The enhanced glucose metabolism in the ventricular septum of HOCM patients may provide a potential explanation for the relationship between the TyG index and HOCM prognosis.

A Narrative Review of Emerging Therapies for Hypertrophic Obstructive Cardiomyopathy

Hypertrophic obstructive cardiomyopathy is a hereditary condition that affects myocardial contraction. In case of failure of pharmacological treatment, alternative approaches might be used that include surgical myectomy, percutaneous transluminal septal myocardial ablation, and radiofrequency ablation. In respect of long-term advantages, surgical septal myectomy remains the therapy of choice for symptomatic hypertrophic obstructive cardiomyopathy. Alcohol septal ablation has been considered an alternative to surgical myectomy, which confers the benefits of a shorter hospital stay, less discomfort, and fewer complications. However, only expert operators should perform it on carefully chosen patients. Further, radiofrequency septal ablation reduces the left ventricular outflow tract gradient and improves the NYHA functional class of patients with hypertrophic obstructive cardiomyopathy, despite complications like cardiac tamponade and atrioventricular block. Further research with a larger sample size is required to compare the radiofrequency approach with established invasive treatment methods for hypertrophic obstructive cardiomyopathy. Septal myectomy has low morbidity and mortality rates, making it the preferred procedure; however, the efficacy and morbidity remain debatable. Advances in invasive techniques, including percutaneous septal radiofrequency ablation and transcatheter myotomy, have provided alternative approaches for reducing left ventricular outflow tract (LVOT) obstruction in patients who are not candidates for traditional surgical septal myectomy. Candidates for alcohol and radiofrequency septal ablation include patients with symptomatic hypertrophic obstructive cardiomyopathy, older adults, and those with multiple comorbidities.

Transaortic Shallow Septal Myectomy and Cutting of Secondary Fibrotic Mitral Valve Chordae-A 5-Year Single-Center Experience in the Treatment of Hypertrophic Obstructive Cardiomyopathy

BACKGROUND

Anomalies of the mitral apparatus have been shown to contribute to left ventricular outflow obstruction in patients with hypertrophic cardiomyopathy (HCM). We report our 5-year single-center experience with a shallow myectomy procedure associated with transaortic mitral valve repair in a cohort of HCM patients.

METHODS

We studied 83 consecutive patients who underwent surgical treatment of symptomatic left ventricular outflow obstruction. In all study patients, a transaortic shallow septal myectomy was performed. Fibrous or muscular structures connecting the papillary muscles to the septum or free wall were resected, and fibrotic secondary chordae of the anterior mitral valve were cut selectively.

RESULTS

We report one death (1.2%) during hospitalization, no iatrogenic ventricular septal defects, and two (2.4%) mitral valve replacements. At discharge, no patients were in New York Heart Association (NYHA) Class III/IV, from 49 (59%) preoperatively. Mean maximal septal thickness decreased from 24 ± 6 to 16 ± 3 mm. Mean outflow gradient decreased from 93 ± 33 to 13 ± 11 mmHg. Grade 3 or 4 mitral regurgitation was noticed in one patient postoperatively, from 32 (39%) before surgery.

CONCLUSIONS

Shallow septal myectomy associated with secondary mitral valve chordal cutting and papillary muscle mobilization provided excellent results offering adequate treatment of outflow obstruction.

Association Between Thyroid Dysfunction and Incidence of Atrial Fibrillation in Patients With Hypertrophic Obstructive Cardiomyopathy

OBJECTIVE

To explore the correlation between the incidence of atrial fibrillation (AF) and thyroid dysfunction in patients with hypertrophic obstructive cardiomyopathy (HOCM).

METHODS

Thyroid function testing in 755 consecutive patients with HOCM were examined at the National Center for Cardiovascular Diseases (China) from October 2009 to December 2013. Patients were divided into four groups according to the TSH levels: TSH<0.55 mIU/L(n=37)、0.55~2.49 mIU/L (n=490)、2.50~9.9 mIU/L (n=211) and >10.00mIU/L(n=17).

RESULTS

A total of 107 patients were diagnosed with AF (14%).(1) Compared to HOCM patients without AF,HOCM patients with AF have older age (P<0.001), higher NT-proBNP (P=0.002), higher Cr (P=0.005), larger left atrial diameter(P=0.001), lower FT3 (P=0.046), higher FT4 (P=0.004).(2) In the four groups according to the TSH levels: TSH<0.55 mIU/L, 0.55~2.49mIU/L, 2.50~9.9mIU/L and ≥10.00mIU/L, the incidence of AF was 27.02%(10/37),10.20%(50/490), 19.43%(41/211), and 35.29%(6/17), respectively. Both high and low TSH levels were associated with an increased incidence of AF. After adjusting for the common risk factor (age, NT-proBNP, and so on), stepwise multiple logistic regression analysis revealed that TSH levels were significantly related to AF incidence.Compared to patients with TSH 0.55~2.49 mlU/L, the adjusted odds ratio of AF for TSH<0.55, 2.50~9.99, ≥10.00 mIU/L were 1.481 (95% CI 0.485~4.518,P=0.490), 1.977 (95%CI 1.115~3.506, p=0.02), 4.301 (95%CI 1.059~17.476, P=0.041), respectively.

CONCLUSION

Our results suggested that thyroid dysfunction was associated with an increased risk of AF in patients with HOCM.

Effects of Septal Reduction Therapy on Acute Cardiovascular Events and All-Cause Mortality in Patients with Hypertrophic Cardiomyopathy

Septal reduction therapy (SRT) -i.e. septal myectomy and alcohol septal ablation-has been performed to treat medically refractory hypertrophic cardiomyopathy (HCM) for decades. However, it is largely unknown whether SRT prevents HCM-related cardiovascular events or death. The objective was to examine the effects of SRT on acute cardiovascular events and all-cause mortality in HCM. We performed a propensity score (PS) -matched study using databases that capture all hospitalizations and outpatient visits in New York state. We identified patients with HCM who underwent SRT between 2007 and 2014 (i.e. the SRT group) and those who had never had SRT but had at least one hospitalization for HCM during the same period (i.e. the control group). We performed PS matching at a 1:1 ratio. The primary outcome was a composite of acute cardiovascular events and all-cause mortality during 0-180 days and 181-360 days. The secondary outcome was 180- and 360-day all-cause mortality. We included 846 patients with HCM (423 PS-matched pairs). Patients who underwent SRT had a lower risk of the primary outcome event (0-180 days: odds ratio [OR], 0.54; 95% confidence intervals (CI), 0.37-0.80; P = 0.002 and 181-360 days: OR, 0.33; 95% CI, 0.22-0.51; P < 0.0001). Furthermore, the risk of all-cause mortality was lower at 180 days (OR, 0.37; 95% CI, 0.22-0.63; P = 0.0003) and 360 days post-SRT (OR, 0.32; 95% CI, 0.20-0.51; P < 0.0001). In conclusion, our PS-matched study using population-based datasets demonstrated that SRT was associated with a reduced risk of a composite of acute cardiovascular events and all-cause mortality in HCM during the first post-SRT year.