Mitral Annular Calcification in Obstructive Hypertrophic Cardiomyopathy: Prevalence and Outcomes

Impact of residual mitral valve regurgitation following septal myectomy for obstructive hypertrophic cardiomyopathy

OBJECTIVE

To evaluate the impact of residual mitral valve (MV) regurgitation (MR) in patients with obstructive hypertrophic cardiomyopathy immediately after myectomy on late survival and the risk of MV reintervention.

METHODS

From October 2001 to February 2024, 3061 patients with hypertrophic cardiomyopathy and dynamic left ventricular outflow tract obstruction underwent septal myectomy. A 1:1 propensity score matching was performed between patients with mild or trivial/no residual MR immediately after cardiopulmonary bypass and patients with moderate or greater residual MR. Long-term survival, MR progression, and the incidence of MV reintervention were analyzed.

RESULTS

Postbypass moderate or greater residual MR was present in 398 patients (13.9%). Matching yielded 398 pairs, with no differences in age (62.1 years vs 61.9 years, P = .397), nor in median peak left ventricular outflow tract gradient on predismissal echocardiography (3 [0-9] mm Hg vs 3 [0-10] mm Hg, P = .585). Late incidence of moderate-severe or greater MR was greater in those with residual MR (15 years: 48.0% vs 11.9%, P = .002), and the incidence of subsequent MV intervention at 15 years was 3-fold greater in those with intraoperative residual MR (14.0% vs 3.9%, P = .007). However, the overall survival of the 2 groups was similar (P = .48).

CONCLUSIONS

Residual MR after septal myectomy is not associated with early or late mortality. However, beyond 5 years' postoperatively, patients with moderate or greater residual MR experience accelerated rates of recurrent MR and require MV reintervention. Residual MR may be attributable to unrecognized mild intrinsic MV disease that progresses late postoperatively.

Durability of mitral valve repair for degenerative mitral valve disease in patients with obstructive hypertrophic cardiomyopathy

OBJECTIVE

In patients with obstructive hypertrophic cardiomyopathy and degenerative mitral regurgitation, some advocate valve replacement because it addresses both valve disease and outflow tract obstruction. To avoid late prosthesis-related complications, we have favored septal myectomy and concomitant mitral valve repair, and the present study assesses the outcomes of this approach.

METHODS

Among 3029 patients with obstructive hypertrophic cardiomyopathy undergoing septal myectomy, 120 received concomitant mitral valve repair for leaflet prolapse. Patients were matched by propensity score to those undergoing mitral valve repair for isolated degenerative mitral regurgitation.

RESULTS

Patients' median age was 63.7 years, and 35.6% were female. Preoperatively, patients with obstructive hypertrophic cardiomyopathy were less likely to have grade 2+ or greater mitral regurgitation (87.6% vs 100%, P < .001). Patients with obstructive hypertrophic cardiomyopathy more often required leaflet plication or Alfieri sutures, whereas those with isolated degenerative mitral regurgitation were more likely to undergo leaflet resections and artificial neochordae placement. Mitral annuloplasty was performed less frequently in patients with obstructive hypertrophic cardiomyopathy (60.0% vs 99.2%, P < .001). Early morbidity and mortality were comparable, with 1 (0.8%) death in each group. There were no significant differences in late survival (10 years, 79% for obstructive hypertrophic cardiomyopathy vs 82% for isolated degenerative mitral regurgitation, P = .85). Recurrence of severe mitral regurgitation at 10 years was similar between groups (10.2% for obstructive hypertrophic cardiomyopathy vs 6.5% isolated degenerative mitral regurgitation, P = .61), as was the rate of mitral valve reoperation (5.5% vs 2.7%, P = .79).

CONCLUSIONS

Mitral valve repair for concomitant degenerative mitral regurgitation in patients with obstructive hypertrophic cardiomyopathy is feasible, safe, and durable, with similar survival and reoperation rates to those of patients with isolated degenerative mitral regurgitation.

Concomitant Mitral Valve Surgery in a Modified Morrow Procedure in Patients with Hypertrophic Obstructive Cardiomyopathy

Ventricular septal myectomy (modified Morrow procedure) is the gold standard surgical intervention for hypertrophic obstructive cardiomyopathy (HOCM). However, the indications for a concomitant mitral valve (MV) procedure to relieve mitral regurgitation (MR) or intrinsic MV pathological changes remain controversial. We aimed to retrospectively analyze this series of patients to evaluate the safety and efficiency of the procedure at our center.We retrospectively reviewed a total of 56 consecutive patients with HOCM who underwent concomitant MV surgery with modified Morrow procedures at our center between January 2019 and December 2021. The baseline characteristics, perioperative data, and postoperative outcomes were examined.The operative mortality rate was 0% among all 56 patients. Two patients had complete atrioventricular block, two patients experienced renal failure, and one patient required reoperation for bleeding. The peak gradient of the left ventricular outflow tract decreased from 93.6 ± 34.4 mm Hg to 20.5 ± 13.0 mm Hg. MR was significantly relieved, and the systolic anterior motion of the MV resolved completely after concomitant MV surgery. During a mean follow-up of 13.8 ± 7.1 months, no patient required cardiac reoperation.Concomitant surgery of the MV during the modified Morrow procedure was performed safely and effectively in the treatment of most types of HOCM in our practice.

Morphological anomalies in obstructive hypertrophic cardiomyopathy: Insights from four-dimensional computed tomography and surgical correlation

Hypertrophic cardiomyopathy (HCM) is a genetic disorder in which left ventricular outflow tract obstruction critically affects symptoms and prognosis. Traditionally, left ventricular outflow tract obstruction was primarily attributed to septal hypertrophy with systolic anterior motion of the mitral valve. However, recent evidence highlights significant contributions from the mitral valve and papillary muscle anomalies, as well as an apical-basal muscle bundle observed in HCM patients. Accurate morphological assessment is essential when considering septal reduction therapy. While transesophageal echocardiography and cardiac magnetic resonance are recommended for assessing the anomalous structures, four-dimensional computed tomography offers superior spatial resolution and multiplanar reconstruction capabilities. These features enable the evaluation of details of the morphological anomalies, such as the apical-basal muscle band, papillary muscle anomalies, subaortic stenosis, and right ventricular outflow tract obstruction. Based on the detailed assessment of these morphological features, four-dimensional computed tomography has been utilized for planning of surgical correction in a comprehensive HCM center. This approach facilitates the intervention strategies and may improve outcomes in septal reduction therapy for obstructive HCM.

Systolic anterior motion-mediated mitral regurgitation and surgical management in hypertrophic obstructive cardiomyopathy

Mitral regurgitation mediated by systolic anterior motion is a typical manifestation in patients with hypertrophic obstructive cardiomyopathy. Although septal myectomy is currently the preferred treatment for patients with drug-refractory hypertrophic obstructive cardiomyopathy, surgical management of associated mitral regurgitation remains controversial. Whether septal myectomy alone or additional valve procedures are required to correct significant mitral regurgitation depends largely on the pathophysiology of each individual. For intervention purposes, it is important to identify the real systolic anterior motion-mediated mitral regurgitation and clarify the mitral structural abnormalities, as well as the other conditions, which may indicate the degree of mitral valve competence. As a first-line imaging modality in the management of hypertrophic cardiomyopathy, echocardiography could provide crucial information for surgical decision making. In this article, we focus on elucidating the typical echocardiographic features of systolic anterior motion-mediated mitral regurgitation and offer an assessment process to determine other contributors to obstruction and mitral regurgitation. Additionally, guidance for surgical decision making for mitral regurgitation in patients with hypertrophic obstructive cardiomyopathy is discussed.

2023 Korean Society of Echocardiography position paper for the diagnosis and management of valvular heart disease, part II: mitral and tricuspid valve disease

This manuscript represents the official position of the Korean Society of Echocardiography on valvular heart diseases. This position paper focuses on the diagnosis and management of valvular heart diseases with referring to the guidelines recently published by the American College of Cardiology/American Heart Association and the European Society of Cardiology. The committee sought to reflect national data on the topic of valvular heart diseases published to date through a systematic literature search based on validity and relevance. In the part II of this article, we intend to present recommendations for diagnosis and treatment of mitral valve disease and tricuspid valve disease.

Insights into the Inherited Basis of Valvular Heart Disease

PURPOSE OF REVIEW: Increases in the availability of genetic data and advances in the tools and methods for their analyses have enabled well-powered genetic association studies that have significantly enhanced our understanding of the genetic factors underlying both rare and common valve diseases. Valvular heart diseases, such as congenital valve malformations and degenerative valve lesions, increase the risk of heart failure, arrhythmias, and sudden death. In this review, we provide an updated overview of our current understanding of the genetic mechanisms underlying valvular heart diseases. With a focus on discoveries from the past 5 years, we describe recent insights into genetic risk and underlying biological pathways. RECENT FINDINGS: Recently acquired knowledge around valvular heart disease genetics has provided important insights into novel mechanisms related to disease pathogenesis. Newly identified risk loci associated valvular heart disease mainly regulate the composition of the extracellular matrix, accelerate the endothelial-to-mesenchymal transition, contribute to cilia formation processes, and play roles in lipid metabolism. Large-scale genomic analyses have identified numerous risk loci, genes, and biological pathways associated with degenerative valve disease and congenital valve malformations. Shared risk genes suggest common mechanistic pathways for various valve pathologies. More recent studies have combined cardiac magnetic resonance imaging and machine learning to offer a novel approach for exploring genotype-phenotype relationships regarding valve disease. Progress in the field holds promise for targeted prevention, particularly through the application of polygenic risk scores, and innovative therapies based on the biological mechanisms for predominant forms of valvular heart diseases.

Treatment Strategies for Hypertrophic Cardiomyopathy: Surgical

Septal myectomy is a well-established procedure for septal reduction in patients with obstructive hypertrophic cardiomyopathy (HCM) who have not responded to medical treatment. The surgical approach is tailored to the unique pathophysiology and septal morphology of the patient. Extended transaortic myectomy is the standard procedure for patients with isolated subaortic obstruction, the most common type of HCM. However, transapical myectomy is a useful adjunct for patients with long or midventricular obstruction and is our preferred technique for ventricular enlargement in patients with severe symptomatic diastolic heart failure because of extensive apical hypertrophy. Septal myectomy provides excellent postoperative outcomes as regards symptom relief and functional improvement, and operative morbidity and mortality rates are low in experienced centers. This article summarizes our current surgical management of patients with HCM and details operative methods and outcomes.

Contemporary Surgical Management of Hypertrophic Cardiomyopathy

More than half of symptomatic patients with hypertrophic cardiomyopathy (HCM) have left ventricular outflow tract (LVOT) obstruction. Septal reduction therapy by septal myectomy can dramatically relieve exertional dyspnea, chest pain, and presyncope in properly selected patients and is an important management pathway for many patients. The distribution and degree of hypertrophy in patients with obstructive HCM are variable and, as discussed in this review, can influence clinical manifestations of the disease and surgical management. Subaortic septal hypertrophy is the most common phenotype of obstructive HCM associated with LVOT obstruction, but midventricular obstruction and apical hypertrophy may occur in isolation or in conjunction with subaortic septal hypertrophy. In many comprehensive HCM centers, transaortic septal myectomy is the preferred method of septal reduction therapy for symptomatic patients with obstructive HCM. Early surgical approaches aimed at alleviating left LVOT obstruction were hampered by a lack of understanding of the anatomy and pathophysiology of obstructive HCM. With the advent of Doppler echocardiography and, more recently, cardiac magnetic resonance imaging, surgeons can precisely assess the location and degree of obstruction, left ventricular size and function, and morphology and function of the mitral valve. This review discusses the current understanding of the role of septal myectomy in the management of patients with HCM and details contemporary operative methods.

Mitral annular calcification in obstructive hypertrophic cardiomyopathy: Incidence, risk factors, and prognostic value after myectomy

BACKGROUND

Mitral annular calcification (MAC) is a risk factor for cardiac surgery, but there is limited study on the prognosis value and the impact for valve function of MAC based on computed tomography (CT) diagnosis after myectomy for hypertrophic obstructive cardiomyopathy (OHCM).

METHODS

Consecutive OHCM patients underwent septal myectomy were compared according to the existence of MAC and its severity in preoperative CT scans. The survival data were evaluated and compared by Kaplan Meier analysis and log rank test. Cox regression analysis was used to evaluate the impact of MAC on endpoint events.

RESULTS

From the entire cohort of 1035 patients, 10.8% had MAC. In multivariate regression, female (OR = 2.23), age (OR = 1.07), aortic annular calcification (OR = 2.52), aortic calcification (OR = 2.56), systolic anterior motion of the mitral valve (SAM) (OR = 0.42), mitral valve thickening (OR = 2.13), and tricuspid regurgitation (OR = 3.12) were independent predictors of MAC. All-cause mortality (3.57% vs. 1.08%, p = 0.031), major adverse cardiovascular and cerebrovascular events (MACCE) (23.32% vs. 13.65%, p = 0.014), recurrent MR > 2+ (8.04% vs. 2.49%, p = 0.001) and NYHA III-IV (11.61% vs. 5.53%, p = 0.012) were more frequent in OHCM patients with MAC after myectomy. MAC was discovered to be an independent predictor of postoperative recurrent MR > 2+ after other risk factors were taken into account (HR 2.47, 95% CI 1.08-5.67, p = 0.0329). Moderate-to-severe MAC was an independent risk factor (HR 2.03, 95% CI 1.09-3.75, p = 0.0244) for long-term major adverse cardiovascular and cerebrovascular events (MACCE).

CONCLUSION

MAC was detected in one-tenth of OHCM patients in preoperative CT scanning and is mainly associated with aging and atherosclerosis. OHCM patients with MAC had a worse prognosis and more recurrent mitral valve regurgitation than those without MAC after septal myectomy.

Sex Differences in Epidemiology, Morphology, Mechanisms, and Treatment of Mitral Valve Regurgitation

Sex-related disparities have been recognized in incidence, pathological findings, pathophysiological mechanisms, and diagnostic pathways of non-rheumatic mitral regurgitation. Furthermore, access to treatments and outcomes for surgical and interventional therapies among women and men appears to be different. Despite this, current European and US guidelines have identified common diagnostic and therapeutic pathways that do not consider patient sex in decision-making. The aim of this review is to summarize the current evidence on sex-related differences in non-rheumatic mitral regurgitation, particularly regarding incidence, imaging modalities, surgical-derived evidence, and outcomes of transcatheter edge-to-edge repair, with the goal of informing clinicians about sex-specific challenges to consider when making treatment decisions for patients with mitral regurgitation.

Prognostic Implication of Mitral Valve Disease and Its Progression in East Asian Patients With Hypertrophic Cardiomyopathy

Background Hypertrophic cardiomyopathy (HCM) is a genetic disorder affecting not only the myocardium but also the mitral valve (MV) and its apparatus. This study aimed to investigate the prognostic implication of MV disease and its progression in East Asian patients with HCM. Methods and Results We assessed MV structure and function on the indexed echocardiogram of 1185 patients with HCM (mean±SD age, 60±14 years; men, 67%) in a longitudinal HCM registry, and 667 patients who performed follow-up echocardiogram after 3 to 5 years were also analyzed. Progression of mitral regurgitation (MR) was defined as the increase of at least 1 grade. Clinical outcomes were defined as a composite of cardiovascular death, heart failure hospitalization, MV surgery or septal myectomy, and heart transplantation. Most of the entire cohort was nonobstructive type (n=1081 [91.2%]). A total of 278 patients (23.5%) showed at least mild MR on indexed echocardiogram. MR, systolic anterior motion, and mitral annular calcification were more prevalent in patients with obstructive HCM. During 7.0±4.0 years of follow-up, presence of MR was independently associated with poor clinical outcomes (hazard ratio [HR], 1.60 [95% CI, 1.07-2.40]; P=0.023). On follow-up echocardiogram, 67 (10.0%) patients showed MR progression, and it was independently associated with poor prognosis (HR, 2.46 [95% CI, 1.29-4.71]; P=0.007). Conclusions In East Asian patients with HCM whose major type is nonobstructive, MV disease is common. MR, systolic anterior motion, and mitral annular calcification are more prevalent in patients with obstructive HCM. The presence and progression of MR are associated with a poor prognosis in patients with HCM.

Impact of Hospital Volume on Outcomes of Septal Myectomy for Hypertrophic Cardiomyopathy

BACKGROUND

Left ventricular outflow tract obstruction is common among symptomatic patients with hypertrophic cardiomyopathy, yet septal reduction by surgical myectomy (septal myectomy [SM]) is performed infrequently in many centers. This study examined the possible relationship between institutional case volume and early outcomes of SM.

METHODS

The Society of Thoracic Surgeons Adult Cardiac Surgery Database was queried for patients with hypertrophic cardiomyopathy who underwent SM from January 2012 to December 2019. The study defined center case volume categories as <1, 1 to 4.99, 5 to 9.99, and ≥10 cases performed on average per year.

RESULTS

The study population included 5935 patients at 481 centers with 933 surgeons. The range of average center volume was <1 to 138 cases per year. Overall early mortality was 2.6%, ventricular septal defect (VSD) occurred in 1.9%, and complete heart block occurred in 9.0%. Concomitant mitral valve (MV) repair was performed in 28.7%, and MV replacement was performed in 17.1%. In multivariable analysis, the lowest annual case volume (average <1 case/y) was consistently associated with greater early mortality (odds ratio [OR], 5.4; CI, 3.0-9.9; P < .001), greater risk of VSD (OR, 9.3; CI ,4.2-20.4; P < .001), increased incidence of complete heart block (OR, 2.0; CI, 1.5-2.7; P < .001), and a higher likelihood of MV replacement (OR, 9.4; CI, 7.5-11.8; P < .001).

CONCLUSIONS

Volume of SM cases varies widely among institutions reporting to the Society of Thoracic Surgeons Adult Cardiac Surgery Database. There appears to be an important association between surgical experience, as reflected by institutional case volume, and early outcomes, including mortality, as well as the occurrence of VSD, heart block, and MV replacement.

Safety and Outcomes of Alcohol Septal Ablation Prior to Transcatheter Mitral Valve Replacement

Background

Patients undergoing transcatheter mitral valve replacement (TMVR) for mitral valve disease caused by severe mitral annular calcification are at risk of left ventricular outflow obstruction. Preemptive alcohol septal ablation (ASA) can potentially mitigate the risk of this complication and is well established in patients with hypertrophic obstructive cardiomyopathy (HCM).

Methods

This retrospective study compared procedural characteristics and outcomes in patients who underwent ASA for TMVR vs HCM.

Results

In total, 102 patients were included, 22 in the TMVR group and 80 in the HCM group. Echocardiography demonstrated increased septal wall thickness in the HCM group (19 ​± ​3.1 ​mm vs 12.7 ​± ​2.0 ​mm; P ​< ​.001). The mean volume of ethanol injected was higher in the HCM group (1.4 ​± ​0.49 ​mL vs 0.8 ​± ​0.2 ​mL; P ​< ​.001). The average neo-left ventricular outflow tract area increased significantly after ASA in the patients undergoing TMVR (135 ​± ​89 ​mm2 vs 233 ​± ​111 ​mm2; P ​< ​.001). Six patients in the TMVR group did not achieve an adequate increase in the neo-left ventricular outflow tract area and required further procedures after ASA. The incidence of post-ASA complete heart block requiring a permanent pacemaker tended to be higher in the TMVR group (35% vs 21%; P ​= ​.195). No patients in either group had ventricular arrhythmia or stroke. Major bleeding complications were 4% in the HCM group and 0 in the TMVR group. The 30-day mortality was 4% in the HCM group and 0 in the TMVR group; however, 1 patient died at 37 ​days in the TMVR group, presumably from late heart block.

Conclusions

Preemptive ASA in patients undergoing TMVR demonstrated safety and short-term clinical outcomes similar to patients with HCM.

Systolic anterior motion of the mitral valve in hypertrophic cardiomyopathy: a narrative review

BACKGROUND AND OBJECTIVE

The prevalence of hypertrophic cardiomyopathy (HCM) is estimated to be 1 in 200 to 500 individuals, with systolic anterior motion (SAM) of the mitral valve (MV) and left ventricular outflow tract (LVOT) obstruction present in 60% to 70%. In this narrative review, we aim to elucidate the pathophysiology of SAM-septal contact and LVOT obstruction in HCM by presenting a detailed review on the anatomy of the MV apparatus in HCM, examining the various existing theories pertaining to the SAM phenomenon as supported by cardiac imaging, and providing a critical assessment of management strategies for SAM in HCM.

METHODS

A literature review was performed using PubMed, EMBASE, Ovid, and the Cochrane Library, of all scientific articles published through December 2021. A focus was placed on descriptive studies, reports correlating echocardiographic findings with pathologic diagnosis, and outcomes studies.

KEY CONTENT AND FINDINGS

The pathophysiology of SAM involves the complex interplay between HCM morphology, MV apparatus anatomic abnormalities, and labile hemodynamic derangements. Echocardiography and cardiac magnetic resonance (CMR) vector flow mapping have identified drag forces, as opposed to the "Venturi effect", as the main hydraulic forces responsible for SAM. The degree of mitral regurgitation with SAM is variable, and its severity is correlated with degree of LVOT obstruction and outcomes. First line therapy for the amelioration of SAM and LVOT obstruction is medical therapy with beta-blockers, non-dihydropyridine calcium-channel blockers, and disopyramide, in conjunction with lifestyle modifications. In refractory cases septal reduction therapy is performed, which may be combined with a 'resect-plicate-release' procedure, anterior mitral leaflet extension, surgical edge-to-edge MV repair, anterior mitral leaflet retention plasty, or secondary chordal cutting.

CONCLUSIONS

Recent scientific advances in the field of HCM have allowed for a maturation of our understanding of the SAM phenomenon. Cardiac imaging plays a critical role in its diagnosis, treatment, and surveillance, and in our ability to apply the appropriate therapeutic regimens. The increasing prevalence of HCM places an emphasis on continued basic and clinical research to further improve outcomes for this challenging population.