Trans-aortic Alfieri stitch at the time of septal myectomy for hypertrophic obstructive cardiomyopathy

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.

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.

Adding Surgical Edge-to-Edge Mitral Valve Repair to Myectomy in Hypertrophic Obstructive Cardiomyopathy: Long-Term Functional and Echocardiographic Outcome

This study evaluates the early and long-term clinical and echocardiographic outcome of edge-to-edge (E2E) mitral valve repair (MVr) concomitant to septal myectomy (SM) in patients with symptomatic hypertrophic obstructive cardiomyopathy (HOCM). A retrospective single-center analysis was performed of patients who underwent isolated SM or SM with E2E MVr from 2011 to 2022. Exclusion criteria were primary mitral valve (MV) disease or concomitant valve surgery. Early and long-term safety, functional and echocardiographic outcomes were compared between groups. Between January 2011 and April 2022, 76 consecutive patients underwent SM for HOCM: 42 patients (55%) underwent SM without additional E2E MVr (Group 1) and 34 patients (45%) underwent SM with additional E2E MVr (Group 2). At latest follow-up, 87% of patients were in New York Heart Association (NYHA) class I-II with no significant differences in NYHA class between groups. Incidence of safety events was comparable between groups. Echocardiographic relief of left ventricular outflow tract (LVOT) obstruction was comparable at early follow-up (P = 0.68), with a significant but small difference in maximum LVOT pressure gradient at latest follow-up in favor of E2E MVr (P = 0.04). Furthermore, patients who underwent SM with E2E MVr showed less residual systolic anterior motion at early and latest follow-up (P = 0.020; P = 0.178). Reintervention on the MV was absent in both groups at 1 year and equally low at follow-up (P = 0.27). This study demonstrates that adding E2E MVr to septal myectomy is as safe as isolated myectomy for the treatment of HOCM. Moreover, the addition of E2E MVr is associated with similar excellent functional improvement and freedom from MV reintervention.

Does a standard myectomy exist for obstructive hypertrophic cardiomyopathy? From the Morrow variations to precision surgery

OBJECTIVES

The purpose of this work is to revisit the history of surgical treatment for obstructive hypertrophic cardiomyopathy (oHCM) over the last 60 years, in the light of advancing knowledge of the pathophysiology of obstruction.

METHODS

In this narrative review the contribution of the different surgical approaches to the field will be assessed in our personal experience in Florence.

RESULTS

Septal myectomy is the treatment of choice in patients with obstructive hypertrophic cardiomyopathy who remain symptomatic despite optimal medical treatment. Over the decades, numerous "theme variations" of the Morrow operation have been proposed, each of them targeting a specific pathophysiological determinant of left ventricular outflow tract obstruction.

CONCLUSIONS

Precision surgery in oHCM patients today depends on the ability of the surgeon to combine and master these variations, with the bird's eye view allowed by climbing on the shoulders of giants.

Surgical Management for Systolic Anterior Motion (SAM) of the Mitral Valve in Obstructive Hypertrophic Myopathy

In patients with obstructive hypertrophic cardiomyopathy, left ventricular outflow tract (LVOT) obstruction can be created by the hypertrophic interventricular septum (IVS) as well as systolic anterior motion (SAM) of the anterior mitral leaflet (AML). Sufficient septal myectomy is a fundamental surgical technique to treat LVOT obstruction, however, direct surgical management for SAM is another key aspect. Besides the hypertrophic IVS, mitral valve, subvalvular apparatus, and papillary muscle may play important role for SAM and several surgical techniques have been proposed to treat SAM in literature. In this review, each surgical technique is classified by the anatomical structure on which the surgical procedure is applied. The AML is the main surgical site and is applied with plication (vertical plication, resection–plication–release strategy), extension (the AML extension, transverse incision of the AML), sutured (edge-to-edge repair, anterior leaflet retention plasty), or traction (floating stitch, papillary muscle-to-anterior annulus stitches, paradoxical stitches, transposition of a directed chorda tendinea to the AML). Height reduction of the posterior mitral valve leaflet and papillary muscle reorientation are other techniques. We should understand theoretical aspects of each technique on correction of anatomical and functional abnormalities of the structure and should apply them under proper indication.

Comprehensive left ventricular outflow tract management beyond septal reduction to relieve obstruction

The surgical management of patients with hypertrophic obstructive cardiomyopathy can be extremely challenging. Relieving the left ventricular outflow tract obstruction in these patients is often achieved by performing a septal myectomy. However, in many instances, septal reduction alone is not enough to relieve the obstruction. Interventions on the sub-valvular apparatus, including the anomalous chordae tendineae and the abnormal papillary muscles, are often required. In this review, we summarize the embryology and the pathophysiology of the different elements that may contribute to the left ventricular outflow tract obstruction in the setting of hypertrophic obstructive cardiomyopathy. In addition, we highlight the different surgical procedures that a surgeon may adopt to relieve the left ventricular outflow tract obstruction, beyond the septal myectomy.

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.

Resurgence of the edge-to-edge repair of the mitral valve

PURPOSE OF REVIEW

To provide a critical review of the application and outcomes of surgical edge-to-edge (E2E) or Alfieri repair for mitral valvulopathy.

RECENT FINDINGS

The E2E repair is a surgical technique to address mitral regurgitation, particularly suited when the responsible mechanism is bileaflet prolapse combined with enlarged annular area. It can also be used for a range of mitral valve pathologies. Surgically, the technique has been employed as a bailout for unsuccessful repair including residual mitral regurgitation because of systolic anterior motion (SAM). E2E repair should be accompanied by a ring annuloplasty for long-term repair durability. The simplicity of this approach makes it an ideal strategy during minimally-invasive mitral valve repair. It may also be performed via a transaortic approach at the time of aortic valve surgery to address less-than-severe mitral regurgitation or to address residual SAM following myectomy for hypertrophic obstructive cardiomyopathy. We review the surgical indication, potential complications including risk of mitral stenosis and the long-term outcomes of E2E repair.

SUMMARY

The E2E surgical repair is a simple and effective surgical strategy to address a wide range of mitral regurgitation. This is an important technique in the surgical armamentarium especially in cases of minimally-invasive mitral valve surgery.

Edge-to-Edge Repair Versus Secondary Cord Cutting During Septal Myectomy in Patients With Hypertrophic Obstructive Cardiomyopathy: A Pilot Randomised Study

BACKGROUND

To evaluate whether the Alfieri technique improves clinical and haemodynamic results and compare it with transaortic mitral valve secondary cord cutting in patients scheduled for septal myectomy for severely symptomatic hypertrophic obstructive cardiomyopathy.

METHODS

Forty-eight (48) patients with moderate-to-severe systolic anterior motion (SAM)-mediated mitral regurgitation were randomly assigned to the Alfieri or Cutting groups in addition to septal myectomy. The primary endpoint was postoperative mean transmitral pressure gradient (TPG). The secondary endpoints were residual left ventricular outflow tract (LVOT) gradient after procedure, residual mitral regurgitation (MR), postoperative SAM, repeating bypass, and survival.

RESULTS

There were no 30-day mortality and ventricular septal defects. The postoperative LVOT gradient was 15.4±7.6 mmHg and 11.1±4.9 mmHg (p=0.078) in the Alfieri and Cutting groups, respectively. The Alfieri technique was associated with higher peak (7.8±3.3 vs 4.7±2.8 mmHg; p=0.014) and mean (3.9±1.7 vs 2.1±1.6 mmHg; p=0.013) TPG. The Cutting group was associated with higher mild MR rate at discharge (six vs no patients; p=0.009). One (1) patient (4.2%) in the Alfieri group required pacemaker implantation owing to conduction disturbances (p=0.312). Two-year (2-year) freedom from late mortality and sudden cardiac death rates were 95.5%±4.4% and 100% for the Alfieri and Cutting groups, respectively (log rank, p=0.317). No patients had New York Heart Association functional class III or IV or moderate or severe MR. The maximum LVOT gradient was 20.4±15.2 mmHg and 16.7±10.4 mmHg, respectively (p=0.330). There were no reoperations during follow-up.

CONCLUSIONS

Both techniques with septal myectomy effectively eliminated SAM-induced MR and LVOT obstructions in hypertrophic cardiomyopathy patients.

Emerging pharmacologic and structural therapies for hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy is the most common inherited heart disease. Although it was first described over 50 years ago, there has been little in the way of novel disease-specific therapeutic development for these patients. Current treatment practice largely aims at symptomatic control using old drugs made for other diseases and does little to modify the disease course. Septal reduction by surgical myectomy or percutaneous alcohol septal ablation are well-established treatments for pharmacologic-refractory left ventricular outflow tract obstruction in hypertrophic cardiomyopathy patients. In recent years, there has been a relative surge in the development of innovative therapeutics, which aim to target the complex molecular pathophysiology and resulting hemodynamics that underlie hypertrophic cardiomyopathy. Herein, we review the new and emerging therapeutics for hypertrophic cardiomyopathy, which include pharmacologic attenuation of sarcomeric calcium sensitivity, allosteric inhibition of cardiac myosin, myocardial metabolic modulation, and renin-angiotensin-aldosterone system inhibition, as well as structural intervention by percutaneous mitral valve plication and endocardial radiofrequency ablation of septal hypertrophy. In conclusion, while further development of these therapeutic strategies is ongoing, they each mark a significant and promising advancement in treatment for hypertrophic cardiomyopathy patients.

The Use of MitraClip for Symptomatic Patients with Hypertrophic Obstructive Cardiomyopathy

Objectives: Current nonpharmacological therapies for symptomatic patients with hypertrophic obstructive cardiomyopathy (HOCM), including septal myectomy and alcohol septal ablation (ASA), carry significant risks for serious cardiac conduction abnormalities. We present a review of the currently available published data regarding the novel use of the relatively low-risk MitraClip® system in the treatment of symptomatic patients. Methods: Data were collected from 4 separate studies on the use of the MitraClip on 15 symptomatic HOCM patients with systolic anterior motion (SAM) of the mitral valve apparatus. Information regarding the degree of mitral regurgitation (MR), left-ventricular outflow tract (LVOT) gradient, and NYHA class was consolidated. Results: After MitraClip treatment, all patients had a resolution of SAM, a reduction in MR, and a reduction in the LVOT gradient from a mean of 75.8 ± 39.7 to 11.0 ± 5.6 mm Hg. Nearly all patients demonstrated improvements in symptoms by either new NYHA class designations or improved exercise tolerance. The procedure was not associated with conduction abnormalities or arrhythmias. Conclusion: MitraClip therapy may be a safe and effective treatment for symptomatic HOCM patients; it can help to avoid the potential risks associated with alternative therapies in high-risk surgical patients.