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.

The Role of Left-Atrial Mechanics Assessed by Two-Dimensional Speckle-Tracking Echocardiography to Differentiate Hypertrophic Cardiomyopathy from Hypertensive Left-Ventricular Hypertrophy.

Hypertrophic cardiomyopathy (HCM) and arterial hypertension (HTN) are conditions with different pathophysiology, but both can result in left-ventricular hypertrophy (LVH). The role of left-atrial (LA) functional changes detected by two-dimensional speckle-tracking echocardiography (STE) in indicating LVH etiology is unknown. METHODS: We aimed to characterize LA mechanics using STE in LVH patients with HCM and HTN. LA 2D volumetric and STE parameters were analyzed in 86 LVH patients (43 HCM and 43 isolated HTN subjects) and 33 age- and sex-matched controls. RESULTS: The volumetric study showed that LA reservoir and conduit function were impaired in the HCM group compared to controls, while, in the HTN group, only LA conduit function was deteriorated. The HCM group had all three STE-derived LA functions impaired compared to controls. The HTN group, consistently with volumetric analysis, had solely LA conduit function reduced compared to controls. Ratios of LA booster-pump strain (S) and strain rate (SR) to interventricular septum (IVS) thickness were the most accurate parameters to discriminate between HCM and HTN. The subgroup harboring sarcomeric pathogenic (P)/likely pathogenic (LP) variants had reduced LA booster-pump S and SR compared with the genotype-negative subgroup. CONCLUSIONS: LA reservoir, conduit, and pump functions are decreased in HCM compared to HTN patients with similar LVH. We report the ratios between LA contraction S/SR and IVS thickness as novel parameters with high accuracy in discriminating LVH due to HCM. The presence of P/LP variants in sarcomeric or sarcomeric-associated genes could be associated with more severe LA dysfunction.

Yield of Rare Variants Detected by Targeted Next-Generation Sequencing in a Cohort of Romanian Index Patients with Hypertrophic Cardiomyopathy.

BACKGROUND: The aim of this study was to explore the rare variants in a cohort of Romanian index cases with hypertrophic cardiomyopathy (HCM). METHODS: Forty-five unrelated probands with HCM were screened by targeted next generation sequencing (NGS) of 47 core and emerging genes connected with HCM. RESULTS: We identified 95 variants with allele frequency < 0.1% in population databases. MYBPC3 and TTN had the largest number of rare variants (17 variants each). A definite genetic etiology was found in 6 probands (13.3%), while inconclusive results due to either known or novel variants were established in 31 cases (68.9%). All disease-causing variants were detected in sarcomeric genes (MYBPC3 and MYH7 with two cases each, and one case in TNNI3 and TPM1 respectively). Multiple variants were detected in 27 subjects (60%), but no proband carried more than one causal variant. Of note, almost half of the rare variants were novel. CONCLUSIONS: Herein we reported for the first time the rare variants identified in core and putative genes associated with HCM in a cohort of Romanian unrelated adult patients. The clinical significance of most detected variants is yet to be established, additional studies based on segregation analysis being required for definite classification.

Current management and surgical advances in patients with hypertrophic obstructive cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is a genetic disease and the most frequent primary cardiomyopathy, affecting 1:500 of the general population. Integrated multimodality imaging, including transthoracic echocardiography, 2- and 3­dimensional transesophageal echocardiography, stress echocardiography, and cardiac magnetic resonance, has provided answers to questions on the management of HCM, leading to standardized protocols. The late 1990s brought the news of a nonsurgical treatment of obstruction in HCM. It is now increasingly evident that septal ablation cannot address all the mechanisms of the left ventricular outflow tract (LVOT) gradient, especially mitral valve involvement. According to American and European guidelines, surgical septal myectomy is the current gold standard treatment. However, deep septal myectomy requires specific operator and institutional experience; therefore, it should not be performed in small community hospitals but only in centers of excellence for HCM treatment. The so-called Ferrazzi technique involves cutting the fibrotic secondary chordae of the mitral valve (MV) and thus helps avoid a deep myectomy by moving the anterior mitral leaflet and the coaptation point of the MV posteriorly away from the septum. This technique, together with careful mobilization of the papillary muscles, helped us achieve excellent results since November 2015, with no mortality, resolution of the LVOT gradient, and MV preservation in all 72 patients. Owing to recent advances in the surgical treatment of hypertrophic obstructive cardiomyopathy, addressing not only the septum but also the MV, the procedure of a deep myectomy has been simplified and mitral regurgitation adequately corrected.