Hypertrophic cardiomyopathy in children

Hypertrophic cardiomyopathy (HCM) characterized by asymmetric ventricular septal hypertrophy, is the commonest cause of sudden cardiac death (SCD) in the young. The underlying etiology of HCM in the childhood and adolescent patients is diverse. Moreover, the prognosis of pediatric HCM depends on the age of presentation and etiology. Despite the complexity of children with obstructive HCM, surgical treatment results in a favorable outcome for carefully selected patients in experienced tertiary referral center in contemporary era. Implantable cardioverter-defibrillator (ICD) remains the most effective and reliable treatment to prevent SCD. New pediatric SCD risk prediction model, which has good discrimination and calibration and can distinguish patients who are most benefit from an ICD implantation, is expected to be further refined in the future.

"Do alternative approaches work in surgical septal myectomy?"

Trans-aortic septal myectomy is the gold standard for septal reduction therapy. This technique has low peri-procedural mortality and excellent long-term survival. Moreover, it relieves the heart failure symptoms and improves the quality of life. Secondary chordal cutting along with septal myectomy has shown to improve the outcome but can potentially cause deterioration of left ventricular function. In patients with relatively thin inter-ventricular septum, abnormalities of mitral valve apparatus may be the main reason for systolic anterior motion and left ventricular outflow tract obstruction. These patients may require additional procedures on the mitral valve to shift the coaptation plane away from outflow tract. Mitral valve replacement should be performed only in patients with intrinsic mitral valve abnormalities that are not suitable for repair and its routine use along with limited septal myectomy should be discouraged. Minimal access surgery although attractive in concept requires more robust data before universal application.

Surgical septal myectomy outcome for obstructive hypertrophic cardiomyopathy after alcohol septal ablation

Background

Although surgical treatment of residual obstruction after alcohol septal ablation (ASA) is often challenging in patients with obstructive hypertrophic cardiomyopathy (OHCM) there are very few relevant clinical reports. Thus, outcomes of surgical septal myectomy (SSM) in this subgroup of patients remain to be determined. Therefore, this study aimed to determine the surgical and follow-up outcomes in patients with OHCM exhibiting residual obstruction after ASA.

Methods

We collected case data for 62 patients with OHCM and residual obstruction after ASA who underwent SSM at Fuwai Hospital between January 2002 and June 2019. Propensity score matching with patients having had a myectomy as the only invasive procedure—was conducted in a 1:2 ratio. Echocardiography parameters, surgery results, and follow-up outcomes were compared between the groups.

Results

The prior ASA group had a higher incidence of complete atrioventricular block (AVB) and subsequently postoperative permanent pacemaker (PPM) implantation than the primary myectomy group (9.7% vs. 1.6%, P=0.01). Two patients died within 30 days after surgery in the prior ASA group, and one patient died in the primary myectomy group, with an operative mortality rate of 3.2% and 0.8%, respectively (P=0.2). The 5-year event-free survival rate was 86.0% in the prior ASA group (median follow-up period: 3.2 years; mean: 3.9±2.6 years; maximum, 10.6 years) and 88.5% in the primary myectomy group (median follow-up period: 2.4 years; mean 2.8±1.7 years; maximum, 9.1 years) (P=0.2). During follow-up, four of 62 (6.5%) patients in the prior ASA group and one of 124 (0.8%) patients in the primary myectomy group progressed to advanced heart failure (P=0.025).

Conclusions

Patients with OHCM following ASA are at an increased risk of developing AVB after SSM. Their surgical outcomes, and long-term survival rate were satisfactory and, osimilar to those for patients having had a myectomy as the only invasive procedure. In addition, they had an increased risk of advanced heart failure after SSM in the present study.

Propensity score matched comparison of isolated, elective aortic valve replacement with and without concomitant septal myectomy: is it worth it?

BACKGROUND

Septal myectomy during open aortic valve replacement (AVR) is an effective surgical treatment for asymmetric secondary basal septal hypertrophy. Concerns regarding higher rates of complications associated with this procedure have been raised - such as permanent pacemaker implantation. The aim of this study was to compare outcomes and complications of patients with and without concomitant septal myectomy using propensity score matching applied to a large, consecutive single center cohort.

METHODS

A total of 2199 consecutive patients undergoing either AVR with concomitant myectomy (AVR-M, N.=212) or AVR alone (N.=1987) were analyzed (2009-2015). Patients with previous cardiac or emergency surgery, concomitant cardiac procedures and endocarditis were excluded. As reference to previously published data, patient characteristics and outcomes of the overall cohort were examined and for comparison between groups propensity score matching utilized.

RESULTS

In the unmatched cohort, AVR-M patients were older (71.2±8 vs. 67.6±10 years, P<0.001) and more often female (68% vs. 37%, P<0.001) in comparison to patients receiving only AVR. After matching (N.=374) no significant difference in baseline features was evident. No significant difference in hospital mortality (2.1% vs. 1.6%, P=1.000) and pacemaker-implantation rate (5.3% vs. 3.7%, P=0.621) was observed. Mid-term survival was comparable between the two groups (86.1±5% vs. 84.4±5% after 6 years, P=0.957). The overall patient cohort showed a survival comparable to that of an adjusted regional normal population (P=0.178).

CONCLUSIONS

This study demonstrates that concomitant myectomy in patients undergoing AVR is a safe surgical technique resulting in comparable hospital mortality and mid-term survival. Concomitant septal myectomy seems not to be associated with an increased pacemaker implantation rate.

Predictors of long-term outcome after septal myectomy in symptomatic hypertrophic obstructive cardiomyopathy patients with previous alcohol septal ablation and residual obstruction

BACKGROUND AND AIM

Recently alcohol septal ablation (ASA) has emerged as an alternative treatment for drug-refractory hypertrophic obstructive cardiomyopathy (HOCM) and a subgroup of HOCM patients with previous ASA may need myectomy. However, subsequent outcome and mechanism of residual obstruction has not been determined. This study aims to determine outcome after myectomy and mechanism of residual obstruction in HOCM patients with previous ASA.

METHODS

From February 2009 to June 2017, 38 HOCM patients with previous ASA underwent surgical septal myectomy at our institution. Seventy-six patients who underwent surgical septal myectomy initially were included as the comparison group through one-to-two propensity score matching method.

RESULTS

Fourteen available cardiac magnetic resonance images revealed inferior location and small area of infarcted myocardium induced by ASA in 12 patients and outside targeted location in two patients. During follow-up (median, 2.4; maximum, 7.8 years), event-free survival at 7 years was 83.2% in the previous ASA group and 94.6% in the comparison group, respectively (P = 0.0378). Multivariable analysis indicated previous ASA (hazard ratio, 4.28; 95% confidence intervals [CI], 1.20-15.26; P = 0.025) and postoperative left ventricular end-diastolic diameter (hazard ratio, 1.14; 95% CI, 1.05-1.23; P = 0.002) were independent predictors of adverse events.

CONCLUSIONS

This study demonstrated that uncontrollable extent and location of infarcted myocardium induced by ASA may attribute to residual obstruction after previous ASA, and the long-term event-free survival after myectomy was inferior. It may provide special precaution to patient selection and the increased number of ASA practiced worldwide.

Surgical Ventricular Septal Myectomy for Patients With Noonan Syndrome and Symptomatic Left Ventricular Outflow Tract Obstruction

Approximately 20% to 30% of patients with Noonan syndrome (NS) have asymmetric left ventricular hypertrophy (LVH) and LV outflow tract obstruction (LVOTO). The role of surgical myectomy in such patients is unknown. We sought to compare clinical features and outcomes of patients with NS and LVOTO with age- and gender-matched patients with nonsyndromic, obstructive hypertrophic cardiomyopathy (HC) after myectomy. Two cohorts were selected and retrospectively analyzed using Mayo Clinic databases from 1996 to 2014. Subjects included patients with NS with LVH and LVOTO and nonsyndromic controls with obstructive HC. Twenty-three patients with NS and LVH were identified, of whom 12 (8 males) underwent myectomy (10 septal and 2 combined septal/apical) for severe LVOTO (10 pediatric and 2 adults; 13 ± 10 year old [range 1 to 39]). Similar echocardiographic improvements were noted in both groups. There were no perioperative deaths. Residual gradients were slightly higher in patients with NS. No improvement was noted in left atrial volume after myectomy in patients with NS. At early follow-up, the majority showed improvement in the New York Heart Association class (88% in NS vs 82% in HC, median of 6 and 2 months, respectively). At late follow-up (median of 7 years), the survival rate was 92% in NS and 100% in HC. In patients with NS with LVH and symptomatic LVOTO, myectomy reduces both gradient and the New York Heart Association class, similar to patients with nonsyndromic obstructive HC. Residual gradients were slightly higher, and left atrial dilation persisted in patients with NS. In conclusion, myectomy should be considered in patients older than 1 year with NS and symptomatic LVOTO.

Surgery for hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a genetically determined cardiac disease characterised by otherwise unexplained myocardial hypertrophy of the left ventricle, and may result in left ventricular outflow tract obstruction. It is the most common cause of sudden cardiac death in young adults due to arrhythmias. Septal myectomy is a surgical treatment for HCM with moderate to severe outflow tract obstruction, and is indicated for patients with severe symptoms refractory to medical therapy. The surgical approach involves obtaining access to the interventricular septum via transaortic, transapical or transmitral approaches, and excising a portion of the hypertrophied myocardium to relieve the outflow tract obstruction. Large, contemporary series from centres experienced in septal myectomy patients have demonstrated a low early mortality of <2 %, excellent long-term survival that matches the general population, and durable relief of symptoms.