Extended septal myectomy for hypertrophic obstructive cardiomyopathy with anomalous mitral papillary muscles or chordae

A preoperative planning procedure of septal myectomy for hypertrophic obstructive cardiomyopathy using image-based computational fluid dynamics simulations and shape optimization

Although septal myectomy is the preferred treatment for medication-refractory hypertrophic obstructive cardiomyopathy (HOCM), the procedure remains subjective. A preoperative planning procedure is proposed using computational fluid dynamics simulations and shape optimization to assist in the objective assessment of the adequacy of the resection. 3 patients with HOCM were chosen for the application of the proposed procedure. The geometries of the preoperative left ventricular outflow tract (LVOT) of patients in the systolic phase were reconstructed from medical images. Computaional fluid dynamics (CFD) simulations were performed to assess hemodynamics within LVOT. Sensitivity analysis was performed to determine the resection extent on the septal wall, and the depth of the resection was optimized to relieve LVOT obstruction while minimizing damage to the septum. The optimized resection was then transferred from systole to diastole to provide surgeons with instructive guidance for septal myectomy. Comparison between preoperative and postoperative hemodynamics showed an evident improvement with respect to the pressure gradient throughout the LVOT. The resected myocardium in the diastolic phase is more extended and thinner than its state in the systolic phase. The proposed preoperative planning procedure may be a viable addition to the current preoperative assessment of patients with HOCM.

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.

2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy" provides recommendations to guide clinicians in the management of patients with hypertrophic cardiomyopathy.

METHODS

A comprehensive literature search was conducted from September 14, 2022, to November 22, 2022, encompassing studies, reviews, and other evidence on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through May 23, 2023, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Hypertrophic cardiomyopathy remains a common genetic heart disease reported in populations globally. Recommendations from the "2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy" have been updated with new evidence to guide clinicians.

2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy" provides recommendations to guide clinicians in the management of patients with hypertrophic cardiomyopathy.

METHODS

A comprehensive literature search was conducted from September 14, 2022, to November 22, 2022, encompassing studies, reviews, and other evidence on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through May 23, 2023, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Hypertrophic cardiomyopathy remains a common genetic heart disease reported in populations globally. Recommendations from the "2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy" have been updated with new evidence to guide clinicians.

Extended septal myectomy versus alcohol septal ablation: clinical results at a national referral centre

OBJECTIVES

Extended septal myectomy and alcohol septal ablation are 2 invasive treatments for hypertrophic obstructive cardiomyopathy. Our goal was to compare which of these techniques achieved a higher reduction in gradients, improvement in New York Heart Association (NYHA) functional class and reduction in medical treatment.

METHODS

It is a single-centre observational and retrospective analysis. We used multivariable regression analyses to assess the association of ablation/myectomy with different outcomes. The odds ratio or coefficient along with the 95% confidence interval was estimated according to the group and adjusted for the corresponding preprocedural variables and EuroSCORE II.

RESULTS

A total of 78 patients underwent septal myectomy, and 25 patients underwent alcohol septal ablation. Basal and Valsalva gradients after myectomy were reduced to a higher degree in comparison to ablation: 21.0 mmHg [P < 0.001, 95% confidence interval -30.7; -11.3], and 34.3 mmHg (P < 0.001, -49.1; -19.5) respectively. Those patients who received a myectomy had a lower probability of having moderate mitral regurgitation (odds ratio = 0.18, P = 0.054). Patients after septal myectomy were more likely to be NYHA functional class I (80.4%), whereas patients after ablation were more likely to be NYHA functional class III (48%). Both groups continued with beta-blocker therapy, but disopyramide could be discontinued after the myectomy in more cases (20%-36% vs 59%-1.3%; P < 0.001), and there was a tendency to discontinue calcium channel blockers (48%-16% vs 15.4-3.8%; P = 0.054).

CONCLUSIONS

After adjustment using preprocedural gradients and EuroSCORE II, myectomy achieves greater reduction in left ventricular outflow tract gradients compared to septal ablation.

Mitral Valve Interventions for Hypertrophic Obstructive Cardiomyopathy

The mitral valve (MV) plays an important role in the pathophysiology of hypertrophic obstructive cardiomyopathy (HOCM). Dynamic left ventricular outflow tract (LVOT) obstruction, caused by systolic anterior motion (SAM), is a common occurrence in most patients with hypertrophic cardiomyopathy and is directly associated with the MV apparatus. First line therapy for HOCM patients is pharmacological, and surgical intervention is often indicated for patients who do not respond to medical therapy. Emerging research on mitral disease in HOCM, specifically mitral regurgitation (MR), demonstrates that these patients frequently do not respond to standard therapeutic options, and can benefit from MV interventions. In this review, we describe the involvement of the MV in the pathogenesis of HOCM, discuss medical therapy, and explore available mitral procedures. Surgical myectomy, often combined with various modifications to the MV apparatus, is frequently necessary to achieve a durable resolution of LVOT obstruction and SAM-related MR. Alcohol septal ablation, an alternative to surgical myectomy, will be briefly mentioned. We also emphasize the role of transcatheter edge-to-edge repair (TEER) as a promising and novel therapeutic option for HOCM patients. Over time, TEER has established itself as an effective and safe procedure, demonstrating success across a spectrum of anatomical variations. The leaflet modification and movement restriction achieved through TEER help reduce SAM and, consequently, have the potential to alleviate LVOT obstruction and SAM-related MR. Furthermore, we propose a treatment algorithm for cases where TEER is a potential course of action for patients who are at high risk for other interventions.

Invasive Management of Hypertrophic Cardiomyopathy With Clinically Important Obstruction: Surgical Myectomy Is Superior, but Only When Accessible

For patients with hypertrophic cardiomyopathy (HCM), a thickened intraventricular septum and systolic anterior motion of the mitral valve (SAM) can contribute to significant left ventricular outflow tract obstruction (LVOTO), mitral regurgitation, and debilitating symptoms. Current guidelines recommend septal reduction therapy through alcohol septal ablation or surgical septal myectomy for patients whose symptoms persist despite medical therapy. Although alcohol septal ablation is a less invasive treatment option, it is not suitable for patients with septal perforator branch anatomy that is not compatible with the procedure, those with midcavitary obstruction, and patients in whom the mechanism of LVOTO is primarily related to SAM. Septal ablation also has a notably higher rate of atrioventricular block requiring permanent pacemaker insertion, and the need for reintervention has been reported to be 15% or more. In contrast, septal myectomy offers direct visualisation and can address thickened septum and mitral valve (MV) anomalies. It can be used to treat a wider variety of anatomies, with lower rates of reoperation. Aside from the more invasive nature of the procedure, a major limitation of septal myectomy, however, is access, because relatively few surgeons specialise in the procedure. This is important because there is a significant correlation between procedural volumes and outcomes. Patients should be evaluated by a multidisciplinary heart team to ensure that they are aware of all treatment options. In this review, we explore the 2 methods of septal reduction therapy and highlight the need for further training of septal myectomy surgeons to ensure access to optimal septal reduction therapies for Canadian patients with HCM.

Comparing long-term outcomes of septal myectomy and mitral valve replacement in hypertrophic cardiomyopathy patients: A retrospective cohort study in Iran

Background

Hypertrophic cardiomyopathy (HCM) affects millions of individuals worldwide. In severe cases, it can cause life-threatening conditions such as left ventricular outflow tract (LVOT) obstruction, mitral regurgitation (MR), and sudden cardiac death, making surgical treatment necessary. This study aimed to report the long-term outcomes of HCM patients undergoing septal myectomy or mitral valve replacement (MVR) and compare the results between different types of surgeries.

Methods

This was a retrospective cohort study on HCM patients who underwent surgical treatment in an Iranian referral center between 2005 and 2021. Patients were divided into three groups according to the type of surgery received: septal myectomy, MVR, or a combination of both surgeries. Patient characteristics, surgical and echocardiographic features, and in-hospital and long-term outcomes were reported and compared between the three groups.

Results

A total of 102 patients with an average age of 53.3 ± 16.9 were included. Twenty-six patients had septal myectomy, 23 had MVR, and 53 had combined septal myectomy and MVR surgery. All surgeries were associated with a significant reduction in interventricular septum thickness and LVOT gradients. After a median of 6.8-year follow-up time, patients with an isolated septal myectomy had significantly lower mortality and major adverse cardiac and cerebrovascular events rates than the other groups.

Conclusion

Isolated septal myectomy showed better long-term survival rates and can correct HCM-related MR, while MVR should be preserved only for intrinsic valve defects. More extensive studies are needed to confirm these findings and achieve a comprehensive guideline on surgical treatment of HCM.

Hypertrophic Cardiomyopathy: Preadolescence, Mitral Valve Disease, and Midventricular Obstruction

Septal myectomy is indicated in patients with obstructive hypertrophic cardiomyopathy (HCM) who have persistent symptoms despite medical therapy, intolerance of medication side effects, or severe resting or provocable gradients. Septal myectomy at high volume centers is safe, with low operative mortality (1%) and low rates of complications such as complete heart block or ventricular septal defect (3% and 0.5%, respectively). Additionally, improved survival following myectomy has been observed when compared to patients with obstructive HCM managed medically or those with nonobstructive HCM. As a longstanding, quaternary referral center for septal myectomy, our institution has built significant experience and expertise in the surgical and medical management of HCM, including atypical HCM, defined as preadolescent patients, those with mitral valve disease, and those with isolated midventricular obstruction. The most important factor of septal myectomy in achieving complete resolution of obstruction and avoiding recurrence is the apical extent of the myectomy trough, which must extend to the septum opposite the papillary muscles. If this cannot be fully achieved via a transaortic exposure, especially in preadolescents and patients with midventricular obstruction, then a transapical approach may be needed. Mitral valve repair is rarely necessary as SAM-mediated MR resolves with adequate myectomy alone, but mitral repair is performed in cases of intrinsic valvular disease. In this manuscript we provide a summary of current operative techniques and outcomes data from our institution on the management of these various categories of HCM.

Anomalous papillary muscle insertion into the mitral valve leaflet in hypertrophic obstructive cardiomyopathy: a lip nevus sign in echocardiography

Background

Anomalous papillary muscle (APM) insertion into the mitral valve leaflet is rare but clinically important in hypertrophic obstructive cardiomyopathy (HOCM). In this study, we report the detection rate of APM insertion into the mitral valve using preoperative imaging modalities and the surgical outcomes of the patients.

Methods

By retrospectively reviewing the clinical records of patients with HOCM who underwent surgical treatment by a single operation group at our center from January 2020 to June 2023, patients with APM insertion into the mitral valve leaflet were identified. Baseline data, image characteristics, and surgical outcomes were analyzed.

Results

The incidence of APM insertion into the mitral valve leaflet was 5.1% (8/157). The insertion site was located at A3 in six cases, which was more common than at A2 (n = 2). Preoperative echocardiography was used to identify two patients (25%) with APM insertion. We observed a particular echocardiographic feature for APM in HOCM patients, which was noted as a "lip nevus sign", with a higher detection rate (62.5%). All patients successfully underwent septal myectomy with concomitant APM excision or mitral valve replacement via the transaortic (n = 5) or transmitral (n = 3) approach. The mean age was 49.0 ± 17.4 years and seven patients (87.5%) were female. Interventricular septum thickness (17.0 mm vs. 13.3 mm, P = 0.012) and left ventricular outflow gradient (117.5 mmHg vs. 7.5 mmHg, P = 0.012) were significantly decreased after surgery. Residual outflow obstruction, systolic anterior motion, and ≥3+ mitral regurgitation were negative. During the follow-up of 26.2 ± 12.2 months, there were no reported operations, adverse events, mitral regurgitation aggravations, recurrences of outflow obstruction, or instances of SAM.

Conclusions

Papillary muscles inserted into the mitral valve leaflet are a subtype of subvalvular malformation in HOCM that requires surgical correction. The lip nevus sign on echocardiography is a characteristic of APM insertion in HOCM and may improve the preoperative detection rate. Adequate myectomy with anomalous papillary muscle excision has achieved good results in reducing the outflow gradient and eliminating mitral regurgitation, with good outcomes at short-to-intermediate follow-up.

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.

Invasive therapies for symptomatic obstructive hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a genetic condition with multiple different genetic and clinical phenotypes. As awareness for HCM increases, it is important to also be familiar with potential treatment options for the disease. Treatment of HCM can be divided into two different categories, medical and interventional. Typically for obstructive forms of the disease, in which increased septal hypertrophy, abnormally placed papillary muscles, abnormalities in mitral valve or subvalvular apparatus, lead to dynamic left ventricular outflow tract (LVOT) obstruction, treatment is targeted at decreasing obstructive gradients and therefore symptoms. Medications like beta blockers, calcium channel blockers, disopyramide can often accomplish this. However, in patients with severe obstruction or symptoms refractory to medical therapy, either surgical correction of the LVOT obstruction or percutaneous via alcohol septal ablation, are treatment options. In this review, we will focus on the invasive treatment of hypertrophic obstructive cardiomyopathy.

Is Congenital Muscular Mitral-Aortic Discontinuity Another Feature of Obstructive Hypertrophic Cardiomyopathy? A Pathology Validation Study

Hypertrophic cardiomyopathy (HCM) is an inherited myocardial disease at risk of sudden cardiac death and heart failure, even requiring heart transplantation. A "muscular mitral-aortic discontinuity" has been reported during surgery in the obstructive form. We aimed to validate these findings through pathological analysis of HCM heart specimens from the cardiovascular pathology tissue registry. Hearts with septal asymmetric HCM from sudden cardiac death, other causes of death, or heart transplantation were included. Sex-matched and age-matched patients without HCM served as controls. Gross and histologic analysis of the mitral valve (MV) apparatus and the mitral-aortic continuity were performed. Thirty HCM hearts (median age, 29.5 years; 15 men) and 30 controls (median age, 30.5 years; 15 men) were studied. In HCM hearts, a septal bulging was present in 80%, an endocardial fibrous plaque in 63%, a thickening of the anterior MV leaflet in 56.7%, and an anomalous insertion of papillary muscle in 10%. All cases but 1 (97%) revealed a myocardial layer overlapping the mitral-aortic fibrous continuity on the posterior side, corresponding to the left atrial myocardium. A negative correlation between the length of this myocardial layer and the age and the anterior MV leaflet length was found. The length did not differ between HCM and controls. Pathologic study of obstructive HCM hearts does not confirm the existence of a "muscular mitral-aortic discontinuity". An extension of left atrial myocardium, overlapping posteriorly the intervalvular fibrosa, is rather visible, and its length decreases with age, possibly as a consequence of left atrial remodeling. Our study highlights the fundamental role of thorough gross examination and the value of organ retention for further analysis in order to validate new surgical and imaging findings.

Hypertrophic obstructive cardiomyopathy with left ventricle outflow tract chordae insertion: Surgery or alcohol septal ablation? A case report

Anomalous insertion of chordae is a rare disease that could be associated with hypertrophic obstructive cardiomyopathy (HOCM), but clinical and echocardiographic diagnoses tend to be delayed. Alcohol septal ablation has emerged as an alternative to surgical myomectomy in HOCM. When a patient showed an anomalous insertion of chordae, physicians generally opt for surgery and not alcohol septal ablation. In this report, we present the case of a lady, with symptomatic HOCM associated with a chord inserted on the left ventricular outflow tract. We succeeded to relieve obstruction by alcohol septal ablation without the need for surgery.

The Role of the Submitral Apparatus in Hypertrophic Obstructive Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiovascular disease, is characterized by unexplained hypertrophy of any myocardial segment, and has a prevalence of 0.2% to 0.5% among the general population. As one of the phenotypes of hypertrophic cardiomyopathy, left ventricular outflow tract obstruction (LVOTO) is associated with high morbidity and mortality, including cardiac death. The integration of various factors, including septal hypertrophy, malformation of the mitral valve apparatus, and an anomalous mitral subvalvular apparatus, may contribute to the occurrence of LVOTO. Previous studies have thoroughly discussed the role of the mitral valve in the mechanisms of systolic anterior motion and LVOTO. Recent studies have shown the importance of determining the potential mechanism of the submitral apparatus in inducing systolic anterior motion and LVOTO. The authors review recent advances in knowledge regarding the submitral apparatus of patients with hypertrophic cardiomyopathy.

Multi-modality management of hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is an autosomal dominant inherited condition defined by left ventricular wall thickness greater than 15 mm in the absence of other conditions that could explain that degree of hypertrophy. Obstructive HCM associated with left ventricular outflow tract obstruction is defined by an intraventricular systolic pressure gradient greater than or equal to 30 mm Hg. Over the past couple of decades, there has been an expansion of both invasive and pharmacotherapeutic options for patients with HCM, with recent guidelines calling for a melody of invasive and non-invasive treatment strategies. There are several invasive therapies including proven therapies such as alcohol septal ablation and septal myectomy. Novel invasive therapies such as MitraClip, radiofrequency septal ablation and SESAME procedure have more recently been promoted. Pharmacological therapy has also dramatically evolved and includes conventional medications such as beta-blockers, calcium channel blockers, and disopyramide. Mavacamten, a novel cardiac myosin inhibitor, may significantly change management. Other myosin inhibitors and modulators are also being developed and tested in large clinical trials. Given significant phenotypical variability in patients with HCM, clinical management can be challenging, and often requires an individualized approach with a combination of invasive and non-invasive options.

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.

Anomalous papillary muscle insertion into mitral valve leaflet: Autopsy study and implications

Anomalous papillary muscle (APM) insertion into the anterior mitral valve leaflet is often associated with hypertrophic cardiomyopathy (HCM) but is reported in other cases as a rare finding. Mere presence does not strictly imply hemodynamic disturbance, and several types exist, with various impacts on left ventricular outflow tract (LVOT) obstruction. The interpretation of isolated anomaly is challenging at autopsy because significant LVOT obstruction is dynamic. We analyzed autopsy cases with APM regarding the site of PM insertion and origin, number of PM bellies, anomalous insertions, heart weight, left ventricle (LV) thickness, LV endocardial fibrosis, subjects' age, sex, cause, and manner of death. A total of 20 cases were identified. Fourteen were identified incidentally, while in 670 systematically examined hearts, the APM was identified in six cases, indicating a prevalence of 0.9%. In eight cases, the manner of death was natural (one case with HCM), and in 12 non-natural. Type II anomaly of PM was most frequent (n = 8), followed by Type III (n = 7) and Type I (n = 5). Subjects who died of natural causes were significantly older and had heavier hearts (median 455 g vs. 330 g; p < 0.05) without difference in LV thickness (median 16 mm vs. 15 mm; p > 0.05). Histology performed in four cases showed a pattern of direct insertion of cardiomyocytes into the leaflet's thick fibrous tissue with a narrow overlapping zone. The APM is rare, can be easily overlooked, and does not imply significant pathology per se. We discussed proper assessment of the significance of this anomaly at autopsy.

[Mitral valve replacement in patients with obstructive hypertrophic cardiomyopathy]

OBJECTIVE

To analyze the incidence and causes of mitral valve replacement in patients with obstructive hypertrophic cardiomyopathy (HCM).

MATERIAL AND METHODS

There were 172 patients (98 women and 74 men) with obstructive HCM and severe mitral valve insufficiency between November 2017 and May 2023. All patients complained of chronic heart failure NYHA class III. Surgical correction of left ventricular outflow tract (LVOT) obstruction and mitral valve repair with elimination of systolic anterior motion were technically successful in 160 (93.0%) patients.

RESULTS

The need for mitral valve replacement was noted in 12 (7.0%) patients. Mean cardiopulmonary bypass time was 83.5±19.2 min (94; 127), aortic cross-clamping - 62.8±14.3 min (70; 102). In 5 cases, primary mitral valve replacement was scheduled due to obvious organic lesion of the mitral valve (tearing of chords, rheumatic lesion with leaflet restriction). In 7 patients, valve replacement was forced after ineffective primary septal myectomy (LVOT pressure gradient, severe mitral insufficiency).

CONCLUSION

Mitral valve replacement is an involuntary strategy after ineffective myectomy with severe mitral insufficiency and high LVOT pressure gradient.

Intraoperative accurate assessment of septal myectomy for hypertrophic obstructive cardiomyopathy (HOCM)

Surgical restoration of the left ventricular outflow tract (LVOT) is necessary for patients suffering from hypertrophic obstructive cardiomyopathy (HOCM), when symptoms are present despite the administration of medical treatment. One point of great significance during the procedure is the evaluation of the LVOT gradient after completion of septal myectomy. Most physicians choose to measure this value by transesophageal echocardiography (TEE) in combination with the direct measurement with the use of needles inserted into the aorta and left ventricle. In this article, we present the implementation of a new technique to estimate the peak-to-peak pressure gradient between the left ventricle and the aorta intraoperatively using a single double lumen central venous catheter inserted through the antegrade cardioplegia cannulation site across the aortic valve into the left ventricle.

Review of Contemporary Invasive Treatment Approaches and Critical Appraisal of Guidelines on Hypertrophic Obstructive Cardiomyopathy: State-of-the-Art Review

BACKGROUND

Hypertrophic obstructive cardiomyopathy (HOCM) is a heterogeneous disease with different clinical presentations, albeit producing similar dismal long-term outcomes if left untreated. Several approaches are available for the treatment of HOCM; e.g., alcohol septal ablation (ASA) and surgical myectomy (SM). The objectives of the current review were to (1) discuss the place of the standard invasive treatment modalities (ASA and SM) for HOCM; (2) summarize and compare novel techniques for the management of HOCM; (3) analyze current guidelines addressing HOCM management; and (4) offer suggestions for the treatment of complex HOCM presentations.

METHODS

We searched the literature and attempted to gather the most relevant and impactful available evidence on ASA, SM, and other invasive means of treatment of HOCM. The literature search yielded thousands of results, and 103 significant publications were ultimately included.

RESULTS

We critically analyzed available guidelines and provided context in the setting of patient selection for standard and novel treatment modalities. This review offers the most comprehensive analysis to-date of available invasive treatments for HOCM. These include the standard treatments, SM and ASA, as well as novel treatments such as dual-chamber pacing and radiofrequency catheter ablation. We also account for complex pathoanatomic presentations and current guidelines to offer suggestions for tailored care of patients with HOCM. Finally, we consider promising future therapies for HOCM.

CONCLUSIONS

HOCM is a heterogeneous disease associated with poor outcomes if left untreated. Several strategies for treatment of HOCM are available but patient selection for the procedure is crucial.

Non-pharmaceutical Interventions for Hypertrophic Cardiomyopathy: A Mini Review

Hypertrophic cardiomyopathy is an inherited cardiovascular disease, and 70% of patients have left ventricular outflow tract obstruction. Ventricular septal myectomy has been the gold standard treatment for most patients with refractory symptoms. Due to higher mortality associated with medical facilities with less experience, alcohol septal ablation has been accepted as an alternative to conventional surgical myectomy. It offers lower all-cause in-hospital complications and mortality, which could be potentially more preferable for patients with serious comorbidities. In recent years, radiofrequency ablation, providing another option with reproducibility and a low risk of permanent atrioventricular block, has become an effective invasive treatment to relieve left ventricular outflow tract obstruction. Moreover, substantial progress has been made in gene therapy for hypertrophic cardiomyopathy. The principal objective of this review is to present recent advances in non-pharmaceutical interventions in hypertrophic cardiomyopathy.

Surgery for Hypertrophic Obstructive Cardiomyopathy: Comprehensive LVOT Management beyond Septal Myectomy

Hypertrophic cardiomyopathy (HCM) is a complex, underestimated, multifaceted disease frequently associated with left ventricular outflow tract (LVOT) obstruction. It is clearly demonstrated that this is due not only to septal hypertrophy but also to systolic anterior motion (SAM) of mitral valve leaflets secondary to mitral valve/subvalvular apparatus abnormalities. Surgical treatment involves performing an extended septal myectomy, eventually followed by ancillary procedures to those structures responsible for maintaining LVOT obstruction, if necessary. In this review, we describe the spectrum of possible surgical techniques beyond septal myectomy and their pathophysiologic rationale.

Mitral Valve Cleft-like Indentations in Hypertrophic Obstructive Cardiomyopathy: Insights From Intraoperative Three-Dimensional Transesophageal Echocardiography

OBJECTIVES

Cleft-like indentations (CLIs) of the mitral valve (MV) are best assessed with three-dimensional (3D) transesophageal echocardiography (TEE). The present study examined the prevalence, characteristics, and surgical effect of MV CLIs in patients with hypertrophic cardiomyopathy (HCM).

DESIGN

Prospective, observational, case-control study.

SETTING

Tertiary medical center.

PARTICIPANTS

The study comprised 90 patients with HCM undergoing myectomy and 59 patients undergoing cardiac surgery for non-MV related indications.

MEASUREMENTS AND MAIN RESULTS

Intraoperative 3D TEE was used to evaluate the presence and characteristics of MV CLIs compared, with a random control group of 59 patients undergoing cardiac surgery for non-MV related indications. Ninety patients with HCM (mean age 54.8 ± 13.3 y, 67.8% male) were compared with 59 control patients (mean age 67 ± 12.7 y, 79.7% male). Three-dimensional TEE images were interpreted by consensus of two experienced echocardiographers. At least one MV CLI was present in 84 patients with HCM (93.3%), compared with 23 control patients (39%; p < 0.01). Compared with control patients, patients with HCM were more likely to have deep MV CLIs (85.6% v 25.4%; p < 0.01) and ≥2 CLIs (52.2% v 26.1%; p = 0.02). Six HCM patients (7%) appeared to have true congenital posterior leaflet clefts versus 0% in control patients (p = 0.08). Preoperative mitral regurgitation severity and jet direction were not associated with the presence of deep or multiple MV CLIs (all p > 0.2). None of the MV CLIs in the HCM group required MV surgical intervention or second pump runs for MV regurgitation correction after myectomy.

CONCLUSION

Deep and multiple MV CLIs are common in patients with HCM undergoing septal myectomy, including possible true posterior clefts, but they are not associated with the premyectomy severity of mitral regurgitation or jet direction, and do not result in surgical MV intervention.

Assessment of mitral valve function in children and young adults with hypertrophic cardiomyopathy using three-dimensional echocardiography

OBJECTIVE

The objective of this study was to assess papillary muscle (PM) and mitral valve (MV) structure and function in children and young adults with mild and moderate hypertrophic cardiomyopathy (HCM) using real-time three-dimensional echocardiography (3DE) and to correlate them with HCM related adverse outcomes.

METHODS

Transthoracic research 3DE was performed in HCM patients and controls matched for age and gender. Anterolateral and posteromedial PM mass, apical displacement of anterolateral PM, and left ventricular (LV) mass were measured and indexed to body surface area. The MV annulus and leaflet structure and function were analyzed. Individual PMs were manually planimetered by tracing the endocardial borders on each mid systole frame, taking care to distinguish PMs as distinct from the LV wall. Apical PM displacement was expressed as ratio of the distance between the apex and the base of the anterolateral PM to the entire length of the LV lateral wall (APL index). All 3DE measurements were correlated to adverse outcomes.

RESULTS

Forty subjects were studied, including 20 HCM patients (age 18.1 ± 9.6 years, 16 male and 4 female), and 20 controls (18.2 ± 9.6 years, 16 male and 4 female). The indexed LV mass in HCM was 74.8 ± 25.8 g/m² compared to 50.8 ± 12.4 g/m² in controls (p = 0.001). The anterolateral, posteromedial and combined PM mass were 3.1 ± 2.2 g/m², 1.7 ± 1.2 g/m² and 4.9 ± 2.7 g/m² in HCM, in contrast to respective measurements of 1.1 ± 0.6 g/m², 1.2 ± 0.6 g/m² and 2.3 ± 0.8 g/m² in controls (p < 0.001, p = 0.062, and p < 0.001, respectively). The mitral valve annular parameters (annulus circumference, height and area) in HCM were not significantly different from controls. The APL index in HCM was less than in controls (0.44 ± 0.07 vs. 0.55 ± 0.04, p < 0.001). The LV lateral wall length and LV mass correlated with adverse HCM outcomes, while the APL index and PM total mass were not associated with adverse events.

CONCLUSION

It is feasible to evaluate PM muscles and MV annulus geometry in children and young adults with HCM using 3DE. The morphologic and functional changes of anterolateral PM may occur in the absence of MV annulus changes. Prospective validation will be required to determine if LV lateral wall length and LV mass may be used as predictors of adverse events.

Mitral endocarditis in hypertrophic obstructive cardiomyopathy with leaflet perforation

We present a case of mitral endocarditis in hypertrophic obstructive cardiomyopathy with systolic anterior motion of anterior leaflet. Perforated anterior leaflet was repaired and extended septal myectomy was concomitantly performed to control systolic anterior motion and mitral regurgitation.

The Role of Mitral Valve in Hypertrophic Obstructive Cardiomyopathy: An Updated Review

Hypertrophic cardiomyopathy (HCM) is the most common inherited heart disease and the most common cause of sudden cardiac death in young population, especially in athletes under 35 years old. Mutations occur primarily in the β-myosin heavy chain gene and involve the cardiac myosin-binding protein C gene. In this review we would like to focus on the importance of the examination of mitral valve apparatus and the mitral valve abnormalities in patients with HCM. Abnormalities in mitral valve (elongated mitral leaflets, displacement of papillary muscles, and systolic anterior motion) may be the primary pathognomonic elements, even in the absence of hypertrophy. Echocardiography is the gold standard for the diagnosis of HCM. Magnetic resonance imaging emerges as one of the most important imaging modalities for precise diagnosis, assisting in risk stratification and treatment strategy. Mitral valve abnormalities take part fundamentally in the formation of systolic anterior motion of the mitral valve and, they have substantially been repaired surgically. Although myectomy addresses the septum reduction, obstruction relief should be maximally achieved with a potential combination of myectomy and mitral valve repair.

Anomalous papillary muscles-Implications in the surgical treatment of hypertrophic obstructive cardiomyopathy

OBJECTIVES

To categorize and assess the functional significance of anomalous papillary muscles in patients undergoing surgical management of obstructive hypertrophic cardiomyopathy.

METHODS

We reviewed the records of operations for obstructive hypertrophic cardiomyopathy and identified 73 patients with an anomalous papillary muscle. Anomalous papillary muscles inserting directly into the body of the anterior mitral valve leaflet were classified as type I, those with both direct insertion into the body of the leaflet and attachment to the free edge of the anterior leaflet were categorized as type II, and anomalous papillary muscles inserting into the free edge of the anterior leaflet were grouped as type III. Additionally, we investigated detection rates by preoperative transthoracic echocardiography, intraoperative transesophageal echocardiography, and cardiac magnetic resonance imaging.

RESULTS

The mean age of patients was 51.9 ± 12.3 years, and 49.3% were male. The anomalous papillary muscle was classified as type I in 31.5% of patients, type II in 35.6%, and type III in 32.9%. Only type I and type II anomalous papillary muscles contributed to left ventricular outflow tract obstruction. The anomalous papillary muscle was detected on preoperative transthoracic echocardiography in 11% of patients and by intraoperative transesophageal echocardiography in 27.4% of patients. No anomalous papillary muscles were identified on cardiac magnetic resonance imaging. All patients underwent septal myectomy with or without (n = 34) associated excision of the anomalous papillary muscle. Excision of the papillary muscles was more common in patients with type I and II (76.4% and 80.8%, respectively) when compared with type III (4.2%). Ten patients underwent mitral valve repair, and 1 patient had mitral valve replacement.

CONCLUSIONS

Papillary muscle abnormalities are important findings in patients with obstructive hypertrophic cardiomyopathy but are not identified preoperatively in the majority of patients. Recognition of anomalous papillary muscles intraoperatively and understanding of the morphologic subtypes are critical to adequate gradient relief and preservation of mitral valve function. The optimum approach involves a transaortic extended septal myectomy associated with the resection of the anomalous papillary muscles in patients with type I and II anatomy.

Aortic regurgitation is common in hypertrophic cardiomyopathy: An echocardiography and cardiovascular magnetic resonance study

PURPOSE

To investigate the incidence, mechanism, and risk factors of aortic regurgitation (AR) in patients with hypertrophic cardiomyopathy (HCM) by using echocardiography and cardiac magnetic resonance (CMR).

METHODS

105 HCM patients, 52 hypertension (HTN) patients and 50 healthy controls (HC) were retrospectively recruited. HCM patients were divided into 38 with AR (HCMAR) subject and 67 without AR. The subaortic complex, D1 (the largest distance of the interventricular septum that protruded into the LVOT) and D3 (the LVOT effective width) were assessed and compared between the two groups of HCM patients.

RESULTS

AR was more common in HCM than in HTN and HC (36 %, 17 %, and 10 %, respectively, P = 0.001). HCM patients with AR were older (58 ± 11 vs. 45 ± 16 years, P < 0.001) and had a higher incidence of hypertension (55 % vs. 33 %, P = 0.03). D1 was greater (13.5 ± 4.4 vs. 10.6 ± 4.0 mm, P = 0.001), and D3 was shorter in the HCMAR group (10.2 ± 5.3 vs. 13.7 ± 5.9 mm, P = 0.003). Anterior mitral leaflet length and left atrial diameter were greater in HCMAR group (all P < 0.05). On multivariable logistic regression analysis, the independent risk factors of AR in HCM patients were LVOTO and age.

CONCLUSIONS

This study demonstrated that AR is a common comorbidity of HCM, especially in patients with LVOTO. LVOTO and age were independent risk factors of AR in HCM patient.

Importance of surgical expertise in septal myectomy for obstructive hypertrophic cardiomyopathy

OBJECTIVE

In 2011, a multidisciplinary hypertrophic cardiomyopathy (HCM) program with a dedicated myectomy surgeon was implemented at our institution. We hypothesized that a dedicated approach allows better identification and management of mitral regurgitation (MR) during septal myectomy (SM) for obstructive HCM with significant mitral regurgitation.

METHODS

Between 2006 and 2018, 181 patients had SM at our institution. This study consists of 53 patients with preoperative moderate or greater MR associated with systolic anterior motion who underwent isolated SM with or without mitral intervention. Patients were divided into those who underwent SM by a dedicated myectomy surgeon (group D, n = 31) or by a non-dedicated surgeon (group ND, n = 22). Primary outcome of interest was rate of mitral valve replacement (MVR) at SM. Secondary outcomes include in-hospital mortality, need for permanent pacemaker, mitral valve reoperation, and residual MR and left ventricular outflow tract gradient on postoperative echocardiography.

RESULTS

12 patients (55%) had a concomitant MVR during septal myectomy in group ND compared to 2 patients (6%) in group D (p < 0.01). Among patients who did not undergo MVR, patients in group D less commonly had residual MR than patients in ND after SM (p < 0.01). Group D had 100% survival with NYHA class I in 94% patients at follow-up visit (p = 0.01). Reoperation for MVR was required in four patients in group ND vs. none in group D (p < 0.01).

CONCLUSIONS

A dedicated surgeon is able to spare the mitral valve in patients undergoing SM. This study emphasizes the importance of surgical expertise in this cohort.

THE PLACE OF CARDIAC COMPUTED TOMOGRAPHY IN PREOPERATIVE PLANNING OF EXTENDED SEPTAL MYECTOMY IN PATIENTS WITH OBSTRUCTIVE FORM OF HYPERTROPHIC CARDIOMYOMATHY

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiomyopathy. Extended septalmyectomy (ESM) is one of the priority methods of treatment of drug-refractory obstructive HCM. In recent years,hospital mortality during surgical correction of obstructive HCM in expert centers does not exceed 1-2 %. However,typical threatening complications of septal myectomy, such as iatrogenic ventricular septal defect (VSD) and rupture of the anterior or posterior walls of the left ventricle (LV), remain a topical issue in surgery of HCM.

OBJECTIVE

to show the role of preoperative CT-planning to predict and reduce possible technical problems associated with ESM, including iatrogenic VSD.

METHODS AND MATERIALS

This study includes 217 symptomatic patients with obstructive HCM, who from April 2016to October 2019 as one of the steps of preoperative planning underwent cardiac CT prior to ESM. Cardiac CT was performed to delineate the left ventricular myocardium, assess the distribution of hypertrophy and the presence ofcrypts. Special attention was also paid to the anatomy of the mitral valve (MV) and subvalvular apparatus. Coronaryartery patency was assessed by CAD-RADS, a standardized method for reporting the results of coronary CT angiography to determine tactics for further management of the patient.

RESULTS AND DISCUSSION

In the study group, the average age of patients was (49 ± 15) years, 48 % - men. All patientshad a symptomatic, drug-refractory obstructive form of HCM. The mean maximum wall thickness of the interventricular septum (IVS) was (20 ± 5) mm (range 16-33). The average LV mass was (118 ± 23) g/m2. 195 patients (89.9 %)had systolic anterior motion ( SAM) of the MV. MV and subvalvular apparatus anomalies were detected in 62 patients(28.6 %). A zone of scarring and regression of IVS after alcohol septal ablation (ASA) was detected in 7 patients(0.3 %) with residual LV outflow gradient. Coronary arteries atherosclerosis was detected in 32 patients (14.7 %).

CONCLUSIONS

Preoperative CT-planning of septal myectomy allows to obtain information on morphology of the LV,IVS, MV and subvalvular apparatus, and gives the surgeon the advantage to form a more accurate plan for the location and volume of septal resection, and avoid complications when correcting obstructive HCM. No iatrogenic VSDwas detected in any of the patient in the study group.

Anterior mitral leaflet length and mitral annulus diameter impact the echocardiographic outcome after isolated myectomy

Background

Myectomy remains the standard surgical treatment of patients with hypertrophic cardiomyopathy (HOCM). New surgical methods developed in the last decades mainly address the mitral valve and are controversial because of their conflicting assumptions. This study assesses the influence of anterior mitral valve leaflet (AML) length and the anterior-posterior diameter of the mitral annulus (MAD) on dynamic left ventricle outflow tract obstruction and mitral regurgitation (MR) after extended myectomy.

Methods

We retrospectively analysed the transthoracic echocardiograms (TTE) of 36 patients. AML length and MAD were obtained from TTE performed before the operation. The greatest maximal left ventricle outflow tract (LVOT) gradient and MR registered in follow-up were analysed. After surgery, patients were divided into two groups; those with moderate or milder MR and/or an LVOT gradient < 30 mmHg (responders), and those with more than moderate MR and/or an LVOT gradient ≥30 mmHg (non-responders).

Results

Patients in responders group had significantly longer AML: 32.3 ± 2.3 mm vs 30.0 ± 3.8 mm (p = 0.03) [parasternal long axis view – PLAX view], 25.9 ± 2.3 mm vs 23.5 ± 2.7 mm (p = 0.008) [four chamber view - 4CH view] and larger anterior-posterior mitral annulus diameter 28.1 ± 2.8 mm vs 25.4 ± 3.2 mm (p = 0.011) than those in non-responders group. Among all analysed patients longer anterior mitral leaflet was correlated with lower postoperative LVOT gradient when measured in PLAX view (p = 0.02) and lower degree of MR due to systolic anterior motion (SAM) when measured in 4CH view (p = 0.009). Greater [AML x mitral annulus] ratio correlated with lower postoperative LVOT gradient in both projections: 4CH (p = 0.025), PLAX (p = 0.012). There was significant reduction in NYHA Class after surgery (p = 0.000). There were no significant differences in NYHA class after surgery (p = 0.633) neither in NYHA class reduction (p = 0.475) between patients divided into responders and non-responders group according to echocardiographic parameters.

Conclusions

Patients with a longer AML and a greater diameter of the mitral annulus are less likely to have mitral regurgitation due to residual SAM and increased LVOT gradient after an extended myectomy. Division of patients according to echocardiographic criteria into responders and non-responders was not in concordance with clinical improvement.

Trial registration

Retrospective study. Approved by ethics committee (IK-NPIA-0021-21/1763/19) at 16.01.2019.

Magnetic resonance imaging of the papillary muscles of the left ventricle: normal anatomy, variants, and abnormalities

Left ventricular papillary muscles are small myocardial structures that play an important role in the functioning of mitral valve and left ventricle. Typically, there are two groups of papillary muscles, namely the anterolateral and the posteromedial groups. Cardiovascular magnetic resonance (CMR) is a valuable imaging modality in the evaluation of papillary muscles, providing both morphological and functional information. There is a remarkably wide variation in the morphology of papillary muscles. These variations can be asymptomatic or associated with symptoms related to LV outflow tract obstruction, often associated with hypertrophic cardiomyopathy. Abnormalities of the papillary muscles range from congenital disorders to neoplasms. Parachute mitral valve is the most common congenital abnormality of papillary muscles, in which all the chordae insert into a single papillary muscle. Papillary muscles can become dysfunctional, most commonly due to ischemia. Papillary muscle rupture is a major complication of acute myocardial infarction that results in mitral regurgitation and associated with high mortality rates. The most common papillary neoplasm is metastasis, but primary benign and malignant neoplasms can also be seen. In this article, we discuss the role of CMR in the evaluation of papillary muscle anatomy, function, and abnormalities.

Early results of optimal septal myectomy using 3-dimensional printed models

Introduction

The completeness of septal myectomy (SM) is the key to surgery of hypertrophic obstructive cardiomyopathy (HOCM), but its planning is still based on echocardiographic findings. The need to perform radical SM requires the development of new cardio-visualisation techniques for monitoring myectomy quality.

Aim

To improve results in centres treating few patients with HOCM using a new method of optimal SM with the help of 3-dimensional models to achieve an ‘ideal’ interventricular septum (IVS) thickness of 10–11 mm.

Material and methods

Between 2017 and 2018, 30 patients underwent optimal SM after computed tomography angiography, creation of a virtual 3-dimensional model of the IVS, computer-aided mapping, virtual SM and 3-dimensional printing of models of the ‘ideal’ IVS and the fragment to be removed.

Results

Initial isolated extended SM (n = 29, 97%) was effective in 23/29 (79%) patients. Four non-fatal complications were observed. A permanent pacemaker was implanted in three patients. No patients required mitral valve replacement. The mean postoperative left ventricle (LV) resting systolic gradient was 7.5 ±4.4 mm Hg, and at the latest follow-up this value was 7.1 ±4.2 mm Hg. The average weight of the excised myocardium was 12.0 g (range: 5.8–22.5 g). At follow-up both volumetric and dimensional LV echocardiography parameters increased compared with preoperative values (p ≤ 0.007).

Conclusions

The proposed optimal SM provides intraoperative monitoring of the shape and volume of the myocardium resected to achieve the ‘ideal’ IVS, true radicality and an increase in the volumetric and dimensional parameters of the LV.

Muscular Mitral Chord Contribution to Left Ventricular Outflow Tract Obstruction in HOCM

Papillary muscle anomaly with a muscular chord directly attached to the anterior mitral leaflet is a rare mitral valve disease. A 62-year-old man with systolic anterior motion of the anterior mitral leaflet and hypertrophic obstructive cardiomyopathy presented to surgical intervention after unsuccessful transcoronary ablation of septal hypertrophy with alcohol. Intraoperative findings revealed a primarily not detected anomalous muscular mitral chord (0.8 × 2.2 cm) connecting the base of the A1 segment to the anterolateral papillary muscle. Resection of this chord and additional septal myectomy treated systolic anterior motion and obstruction of the outflow tract. In spite of the infrequent occurrence, anomalies of the subvalvular apparatus, such as muscular chords, should be ruled out by thorough transesophageal echocardiography imaging before decision on the therapeutical strategy.

Role of Preoperative Cardiovascular Magnetic Resonance in Planning Ventricular Septal Myectomy in Patients With Obstructive Hypertrophic Cardiomyopathy

In obstructive hypertrophic cardiomyopathy (HC), extreme heterogeneity of septal morphology makes septal myectomy particularly challenging. Although cardiovascular magnetic resonance (CMR) reconstructs ventricular anatomy with high spatial resolution, CMR is not used systematically to plan preoperatively septal myectomy. In this study, we report our results with using CMR to plan the extent of septal excision in 112 consecutive HC patients who subsequently underwent myectomy. Depth and length of the myectomy planned at CMR were compared with those of the septal muscle excised in a single piece in all patients. Anterior septum maximal thickness at CMR was 22 ± 5 mm and excised muscle thickness 9 ± 3 mm. Planned myectomy length was 35 ± 11 mm (range 17 to 65) and excised muscle length 38 ± 10 mm (range 10 to 70), indicating extension of septal resection to mid-cavity. Thickness and length of the planned myectomy showed a significant correlation with the excised muscle (R² = 0.345; p <0.001; and R² = 0.358; p <0.001, respectively). Deep septal crypts were identified at CMR in 12(11%) patients, preventing muscle excision from areas at increased risk of iatrogenic septal defect. Large aberrant muscle bundles that could decrease mid-cavity dimension were identified at CMR and excised in 26(23%) patients. In the 55 patients with postoperative CMR, qualitative comparison of pre and postoperative ventricular morphology showed a smooth and apically extended myectomy. In conclusion, CMR planning of septal myectomy provided high resolution images of septal morphology and allowed us to perform a standardized and apically extended septal excision that was associated with favorable outcome. Our novel approach could make myectomy more accessible to cardiovascular surgeons.

Correction of Left Ventricular Outflow Tract Obstruction Caused by Anomalous Papillary Muscle and Subaortic Membrane

This paper presents a case study of a 30-year-old male patient with dyspnea on exertion had echocardiographic diagnosis of aortic subvalvar stenosis. Discrete mitral regurgitation and aortic valve dysplasia with mild to moderate insufficiency and hypertrophic cardiomyopathy were also noted. During surgery, a rare condition was identified: presence of papillary muscle anomaly associated with the subaortic membrane as a cause of obstruction of the left ventricular outflow tract. With the resection of these structures and a mitral valve annuloplasty, the patient evolved with a significant improvement of clinical condition and heart failure, with no residual mitral insufficiency.

Minimally Invasive Versus Full-Sternotomy Septal Myectomy for Hypertrophic Cardiomyopathy

OBJECTIVE

Septal myectomy remains the criterion standard for the treatment of patients with hypertrophic obstructive cardiomyopathy refractory to medical therapy. There have been few reports of minimally invasive approaches. This study compared a minimally invasive septal myectomy performed at our institution with the traditional full-sternotomy approach.

METHODS

Patients receiving a stand-alone septal myectomy were retrospectively reviewed from November 1999 to December 2016 (N = 120). Patients were stratified by surgical approach: traditional full sternotomy (n = 34) and ministernotomy (n = 86). Preoperative and perioperative variables were compared as well as follow-up symptomatic and echocardiographic outcomes.

RESULTS

Both groups had a significant decrease in New York Heart Association class heart failure symptoms (P < 0.001). At a mean ± SD follow-up time of 2.0 ± 3.4 years, postoperative New York Heart Association class distribution was similar between ministernotomy and full sternotomy (P = 0.684). Follow-up resting left ventricular outflow tract gradient was also similar between ministernotomy and full sternotomy (11 mm Hg ± 15 vs 9 mm Hg ± 13, P = 0.381). Perioperatively, ministernotomy was not significantly different from full sternotomy in median cardiopulmonary bypass time (81 minutes vs 78 minutes, P = 0.101) but had a slightly longer median cross-clamp time (39 minutes vs 35 minutes, P = 0.017). Major complications were similar in the two groups. There was one 30-day mortality in the full-sternotomy group, but no in-hospital deaths.

CONCLUSIONS

Septal myectomy performed using a minimally invasive approach has similar outcomes to the criterion standard operation done through a full sternotomy. It represents a feasible option for patients with hypertrophic obstructive cardiomyopathy unresponsive to medications.