What is the best surgical treatment for obstructive hypertrophic cardiomyopathy and degenerative mitral regurgitation?

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.

Extended septal myectomy for obstructive hypertrophic cardiomyopathy and its impact on mitral valve function

AIMS

Septal myectomy is the treatment of choice for hypertrophic obstructive cardiomyopathy (HOCM). Around 30-60% of patients with HOCM have a secondary mitral valve regurgitation due to systolic anterior motion (SAM). We report our experience with extended septal myectomy and its impact on the incidence of concomitant mitral valve procedures.

METHODS

This is a retrospective study on 84 patients who underwent SM from January 2008 to February 2022. Surgical procedure was performed according to the concept of 'extended myectomy' described by Messmer in 1994. Follow-up outcomes in terms of survival, hospital admissions for heart failure or MV disease, cardiac reoperations, and pacemaker (PMK) implantation were recorded.

RESULTS

Mean age was 61 ± 15 years. Mitral valve surgery was performed in seven cases (8%); particularly only one patient without degenerative mitral valve disease underwent mitral valve surgery, with a plicature of the posterior leaflet. In-hospital mortality was 5%. Mitral valve regurgitation greater than mild was present in four patients (5%) at discharge. Twelve-year survival was 78 ± 22%. Cumulative incidence of rehospitalization for heart failure and rehospitalization for mitral valve disease was 10 ± 4 and 2.5 ± 2.5%, respectively. PMK implantation was 5% at discharge, with a cumulative incidence of 15 ± 7%. Freedom from cardiac reoperations was 100%.

CONCLUSION

Septal myectomy for HOCM is associated with good outcomes. Although concomitant surgery on the mitral valve to address SAM and associated regurgitation has been advocated, these procedures were needed in our practice only in patients with intrinsic mitral valve disease. Adequate myectomy addresses the underlying pathophysiology in most patients.

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.

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.

Optimal Management of Mitral Regurgitation Due to Ruptured Mitral Chordae Tendineae in Patients With Hypertrophic Cardiomyopathy

There is continued controversy regarding surgical management of patients with hypertrophic cardiomyopathy (HCM) and intrinsic mitral valve disease; some clinicians favor prosthetic replacement as this corrects left ventricular outflow tract (LVOT) obstruction and valve leakage. In this study, we investigated the management and late outcome of operation for mitral regurgitation (MR) due to ruptured chordae tendineae in patients with HCM. We analyzed 49 consecutive patients with HCM and MR due to ruptured mitral valve chordae. Echocardiograms and operative reports were reviewed to classify valve anatomy and surgical methods. Information on late outcomes was obtained from electronic medical records and follow-up surveys. The mean age of the 36 men and 13 women was 61.9 ± 12.5 years; significant resting or provoked LVOT obstruction was present at the time of surgery in 46 patients. During the index operation, mitral valve repair was performed in 45 patients, and prosthetic replacement was necessary for 4 patients. Concomitant septal myectomy was performed in 46 patients. There were no hospital deaths or deaths within 30 days of operation. Five and ten-year survival estimates (Kaplan-Meier) were 92% and 71%. During follow-up at a median of 7.9 years, 3 patients underwent reoperation for MV replacement, 5 days, 3 years, and 14 years following valve repair. Ruptured mitral chordae may result in severe mitral valve regurgitation in patients with hypertrophic cardiomyopathy. Valvuloplasty at the time of septal myectomy is safe with an acceptably low rate of recurrent MR requiring prosthetic replacement.

Hypertrophic Obstructive Cardiomyopathy: Discrepancy Between Hemodynamic Measurements in the Cardiac Laboratory and Operating Room Is to Be Expected

OBJECTIVES

It is not uncommon to observe some discrepancy in hemodynamic values characterizing left ventricular outflow tract (LVOT) obstruction preoperatively and in the operating room in patients with hypertrophic obstructive cardiomyopathy. Interpretation of this discrepancy can be challenging. To clarify the extent of the discrepancy, the authors compared hemodynamic variables in patients undergoing septal myectomy at the time of preoperative and intraoperative evaluation.

DESIGN

Retrospective study.

SETTING

Single academic medical center.

INTERVENTIONS

Medical records review, study group-173 patients.

MEASUREMENTS AND MAIN RESULTS

While there was no statistically significant difference in resting peak LVOT gradients by preoperative transthoracic echocardiography (TTE) compared to intraoperative transesophageal echocardiography (46 mmHg [19-87 mmHg] v 36 mmHg [16-71 mmHg], p = 0.231), the former were higher compared to direct needle-resting LVOT gradient measurements before myectomy (49 mmHg [19-88 mmHg] v 32 mmHg [14-67 mmHg], p = 0.0022). The prevalence of systolic anterior motion was high (94.6% v 91.6%, P = 1.000) both on pre- and intraoperative evaluation. The incidence of moderate/severe mitral was higher intraoperatively (p < 0.0001). Pulmonary artery systolic pressures measured by pulmonary artery catheter provided higher values compared to preoperative TTE estimate (39 mmHg [34-45 mmHg] v 34 mmHg [28-41 mmHg], p < 0.0001).

CONCLUSIONS

Discrepancy between hemodynamic measurements in the cardiac laboratory and operating room is common and generally should not affect planned patients' care. These changes in hemodynamics might be explained by preoperative fasting, anesthetic agents, volume shifts while supine, and positive-pressure ventilation, as well as the difference in measurement techniques.

Management of the mitral valve in patients with obstructive hypertrophic cardiomyopathy

Septal myectomy is the gold standard treatment option for patients with obstructive hypertrophic cardiomyopathy whose symptoms do not respond to medical therapy. This operation reliably relieves left ventricular outflow tract gradients, systolic anterior motion of the mitral valve, and associated mitral valve regurgitation. However, there remains controversy regarding the necessity of mitral valve intervention at the time of septal myectomy. While some clinicians advocate for concomitant mitral valve procedures, others strongly believe that the mitral valve should only be operated on if there is intrinsic mitral valve disease. At Mayo Clinic, we have performed septal myectomy on more than 3000 patients with obstructive hypertrophic cardiomyopathy, and in our experience, mitral valve operation is rarely necessary for patients who do not have intrinsic mitral valve disease such as leaflet prolapse or severe calcific stenosis. In this paper, we review anatomical considerations, imaging, and surgical approaches in the management of the mitral valve in hypertrophic cardiomyopathy.

The Surgeon's View of the Left Ventricular Outflow Tract in Congenital Heart Surgery

Left ventricular outflow tract (LVOT) obstruction is a component of many forms of congenital heart disease, including hypertrophic cardiomyopathy, membranous subaortic stenosis, tunnel subaortic stenosis, and outflow tract obstruction related to atrioventricular septal defects. We have gained a particularly extensive experience with the diagnosis and treatment of hypertrophic cardiomyopathy, having performed septal myectomy in over 3,800 patients. In the setting of this review of LVOT obstruction, we use hypertrophic cardiomyopathy as a template by which other pathologies causing LVOT obstruction can be understood. We review important surgical issues in patient selection, diagnostic evaluation, interpretation of imaging, and operative management. To this end, the review focuses on obstructive hypertrophic cardiomyopathy and then broadens to discuss other pathologies causing LVOT obstruction, with important similarities and differences in their management. These other pathologies share some similar presentations and operative techniques, and at times can be confused with hypertrophic cardiomyopathy, but also have important distinctions of which the surgeon should be aware.

Minimally Invasive Surgery for Hypertrophic Obstructive Cardiomyopathy With Mitral Regurgitation

BACKGROUND

To summarize the safety and effect of minimally invasive surgery for hypertrophic obstructive cardiomyopathy (HOCM) with significant mitral regurgitation through a single transaortic approach via right minithoracotomy.

METHODS

From 2008 to 2017, 51 HOCM patients with significant mitral regurgitation underwent minimally invasive surgery via right minithoracotomy. Preoperative peak left ventricular outflow tract pressure gradient (LVOTPG) was 96.53 ± 28.72 mm Hg. Preoperative average interventricular septum thickness was 24.31 ± 3.52 mm. All patients had significant mitral regurgitation with systolic anterior motion phenomenon. An oblique incision was made on the anterior wall of ascending aorta or aortic root. Modified Morrow procedure and edge-to-edge mitral valvuloplasty were performed through the single transaortic approach via right minithoracotomy.

RESULTS

All patients successfully underwent the minimally invasive surgery through the single transaortic approach via right minithoracotomy. At discharge, postoperative peak LVOTPG (18.16 ± 6.41 mm Hg) and interventricular septum thickness (14.33 ± 1.99 mm) were significantly decreased compared with preoperative values (P < .05). All patients had no or trivial mitral regurgitation. The average peak mitral valve pressure gradient was 3.39 ± 1.82 mm Hg. Systolic anterior motion phenomenon disappeared in all patients. During follow-up, peak LVOTPG was 19.27 ± 6.10 mm Hg; average interventricular septum thickness was 14.67 ± 1.87 mm. All patients had no or trivial mitral regurgitation. Average peak mitral valve pressure gradient was 3.04 ± 1.52 mm Hg. No systolic anterior motion phenomenon occurred.

CONCLUSIONS

Minimally invasive surgery of modified Morrow procedure and edge-to-edge mitral valvuloplasty through a single transaortic approach via right minithoracotomy could be safely and effectively applied for patients with HOCM and significant mitral regurgitation, which could also effectively eliminate systolic anterior motion phenomenon and without mitral valve stenosis.

Surgical management of hypertrophic obstructive cardiomyopathy

OBJECTIVE

Septal myectomy is the most effective treatment modality for hypertrophic obstructive cardiomyopathy. A retrospective study was conducted to evaluate outcomes of surgical myectomy alone or with concomitant mitral valve procedures.

METHODS

From December 2011 through December 2016, a total of 41 patients with symptomatic hypertrophic obstructive cardiomyopathy were operated. There were 14 females and 27 males, aged between 18 and 73 years (mean 49.8 years). All patients had drug refractory symptoms (dyspnea, palpitation, chest pain, fainting, limitation of daily physical activities). Twenty-one patients received septal myectomy alone, 10 patients had SM with mitral valve repair and 10 patients had SM with mitral valve replacement. The average follow-up was 38.45 ± 12.18 months.

RESULTS

Surgery led to symptomatic improvement in all patients. None of the patients were left with NYHA Class III and IV symptoms after surgery. The improvement in left ventricular outflow tract gradient was from 116.65 mmHg preoperatively to 22.47 mmHg. Mean septal thickness decreased from 2.35 to 1.74 cm. Post procedure permanent pacemaker implantation was required for one patient due to complete heart block, and 2 intracardiac devices were implanted due to resistant arrthymia. None of the patients required a repeat procedure during follow-up period. Operative mortality was 2.4%.

CONCLUSION

Septal myectomy is safe and effective. Concomitant mitral operations do not increase morbidity and mortality.

Robotic Septal Myectomy Without Anterior Leaflet Incision during Mitral Valve Repair

Bulging subaortic septum in hypertrophic cardiomyopathy is a potential risk factor for systolic anterior motion after mitral valve repair. Systolic anterior motion may cause postoperative mitral regurgitation and left ventricular outflow tract obstruction despite conservative management. During "minimally invasive endoscopic" and "robotic" mitral repair procedures, systolic anterior motion is prevented with concomitant septal myectomy through the mitral valve orifice. Technically, the exposure of the bulging subaortic septum is traditionally done with detachment of the anterior mitral leaflet from its annulus, leaving a 2-mm rim of leaflet attached to the annulus. The leaflet is then sutured after myectomy. As an alternative technique in robotic surgery, the exposure of the subaortic septum is feasible without anterior leaflet incision with the use of dynamic atrial retractor in mitral repair procedures. Here, we present a patient who underwent concomitant robotic mitral valve repair with posterior chordal implantation, ring annuloplasty, and septal myectomy without anterior leaflet incision using the da Vinci surgical system.

Individualized surgical strategies for left ventricular outflow tract obstruction in hypertrophic cardiomyopathy

OBJECTIVES

Surgical strategies to treat drug refractory left ventricular outflow tract obstruction (LVOTO) in hypertrophic cardiomyopathy include septal myectomy (SM) and, less frequently, mitral valve (MV) repair or replacement. The primary aim of this study was to report the surgical technique and management outcomes in a consecutive group of patients with variable phenotypes of hypertrophic cardiomyopathy in a broad national specialist practice.

METHODS

A total of 203 consecutive patients, 132 men (mean age 48.6 ± 14.6 years) underwent surgery for the management of LVOTO. Surgical approaches included SM (n = 159), SM with MV repair (n = 25), SM with MV replacement (n = 9) and MV replacement alone (n = 10). Specific surgical approaches were performed based on the underlying mechanism of obstruction. Eleven (5.4%) patients had previous alcohol septal ablation for the management of LVOTO. Concomitant non-mitral cardiac procedures were carried out in 22 (10.8%) patients.

RESULTS

Operative survival rate was 99.0% with 2 deaths within 30 days. The mean bypass time was 92.9 ± 47.8 min, with a mean length of hospital stay of 10.5 ± 7.8 days. Surgical complications included 3 ventricular septal defects requiring repair (1.5%), 1 Gerbode defect surgically repaired, 2 aortic valve repairs (1.0%), 2 transient ischaemic attacks (1.0%) and 4 strokes (2.0%). Thirty-nine (19.2%) patients had perioperative new-onset atrial fibrillation and 8 (3.9%) patients had unexpected atrioventricular block requiring a permanent pacemaker. Mean resting left ventricular outflow tract gradient improved from 70.6 ± 40.3 mmHg preoperatively to 11.0 ± 10.5 mmHg at 1 year postoperatively (P < 0.001). Mean New York Heart Association class improved from 2.6 ± 0.5 preoperatively to 1.6 ± 0.6 at 1 year after the procedure.

CONCLUSIONS

In variable phenotypes of LVOTO in hypertrophic cardiomyopathy, an individualized surgical approach provided effective reductions in left ventricular outflow tract gradients and good symptomatic relief with acceptable mortality and morbidity.

Numerical simulation study on systolic anterior motion of the mitral valve in hypertrophic obstructive cardiomyopathy

BACKGROUND

The hydrodynamic mechanisms of systolic anterior motion (SAM) of the mitral valve in hypertrophic obstructive cardiomyopathy (HOCM) remain unclear.

METHODS

Based on computed tomography (CT) images and clinical data, pre- and post-operative computational models of the left ventricle were constructed for 6 HOCM patients receiving septal myectomy. SAM was abolished in 5 patients and persisted in one after septal myectomy surgery. The obtained simulation results including flow field of the left ventricle and mechanical behaviors of the mitral valve (MV) between pre- and post-operative FSI models were compared.

RESULTS

The pressure difference and shear stress on the mitral valve leaflets (MVL) were relatively high pre-operatively, and decreased significantly after satisfactory surgery, but remained high following failed surgery. The significant increase in coaptation-to-septal distance was found when SAM was abolished.

CONCLUSIONS

Our results indicated that high pressure difference and shear stress on the MVL might directly initiate SAM in HOCM. Successful septal myectomy enlarged the coaptation-to-septal distance sufficiently to keep the MVL away from the ejection flow, thereby eliminating SAM.

Surgical treatment for hypertrophic cardiomyopathy: a historical perspective

Our understanding of hypertrophic cardiomyopathy (HCM) as a disease entity has increased dramatically over the last half century. There has been a concerted effort by several surgical groups to develop operative techniques to relieve left ventricular outflow tract (LVOT) obstruction and alleviate symptoms. This paper traces the development of transaortic septal myectomy, the current gold standard therapy for relief of LVOT obstruction, in symptomatic patients refractory to medical treatment. In addition, we introduce newer methods for myectomy that have expanded the role of surgery in patients with various forms of HCM.

Hypertrophic obstructive cardiomyopathy: the Mayo Clinic experience

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is a primary myocardial disease characterized by left ventricular hypertrophy in the absence of other etiologies. Clinical presentation may vary from asymptomatic to sudden cardiac death. Medical treatment is the first-line therapy for symptomatic patients. Extended left ventricular septal myectomy is the procedure of choice if medical treatment is unsuccessful or intolerable.

MAYO CLINIC EXPERIENCE

More than 3,000 patients have had septal myectomy for HCM at the Mayo Clinic (MN, USA) from 1993 to 2016. Risk of hospital death after isolated septal myectomy for obstructive HCM is <1% and is similar to the risk of operation for elective mitral valve repair. Complications, such as complete heart block requiring permanent pacemaker, are uncommon (2%), although partial or complete left bundle branch block is a frequent finding on the postoperative ECG. Relief of left ventricular outflow tract (LVOT) obstruction with septal myectomy dramatically improves symptoms and exercise capacity in symptomatic patients with obstructive HCM. More than 90% of severely symptomatic patients have improvement by at least two functional classes, and reduction of outflow gradients by myectomy decreases or eliminates symptoms of dyspnea, angina and/or syncope. Basal obstruction with systolic anterior motion (SAM) is treated by transaortic myectomy. The transapical approach was applied in 115 patients with obstructive midventricular and apical variants of HCM between 1993 and 2012. All patients with midventricular obstruction had gradient relief and none developed an apical aneurysm or ventricular septal defect. Recurrent obstruction after satisfactory myectomy was rare.

CONCLUSIONS

Septal myectomy effectively and definitively relieves LVOT obstruction and cardiac symptoms in patients with obstructive HCM. In experienced centers, early mortality for isolated septal myectomy is less than 1%, and overall results are excellent and continue to improve in the current era.

Long-term outcome of simultaneous septal myectomy and anterior mitral leaflet retention plasty in hypertrophic obstructive cardiomyopathy: the Berlin experience

BACKGROUND

Various surgical strategies designed to relieve left ventricular outflow tract obstruction (LVOTO) and correct mitral regurgitation (MR) in hypertrophic obstructive cardiomyopathy (HOCM) have evolved, yet reports on the long-term outcomes of each technique are scarce. We provide an update on over 20 years' experience at our institution in the standardized surgical treatment of HOCM.

METHODS

Between April 1986 and April 2014, 320 cases of endomyocardial resection and 305 septal myectomies were performed at our institution. Out of this sample, 57 patients (mean age 38±2.5 years, median 16.2, range 3 months-79.8 years) underwent surgery for HOCM involving septal myectomy and anterior leaflet retention plasty (ALRP), intended to obviate the systolic anterior motion (SAM) phenomenon. The preoperative mean LVOT pressure gradient was 98.98±26.2 (median 90, range 60-160) mmHg with moderate-severe MR. Standard transaortic septal myectomy was performed by resecting long blocks of septal myocardium, continued apically beyond the point of the mitral-septal contact. Through a left atriotomy, the segment of anterior mitral leaflet (AML) closest to the trigones was sutured to the corresponding posterior annulus on both sides. Cardiopulmonary bypass was resumed for repeat septal myectomy if the LVOT pressure gradient was greater than 20 mmHg.

RESULTS

Following surgical correction, the mean LVOT pressure gradient was significantly decreased to 12.3±2.7 (median 14, 18-25) mmHg (P<0.001). Septal thickness was reduced from a preoperative mean of 28.2±3.4 (median 30, 25-34) to 10.5±1.1 (12, 15-23) mm (P<0.001). During a mean follow-up of 17.5±1.3 years (median 12, range 1-23.2 years), MR was trivial in 87% and SAM was non-existent in all, outcomes that were maintained at the latest follow-up. Two patients underwent mitral valve (MV) replacement 1 and 5 years after ALRP for recurrent MR. Two patients eventually underwent heart transplantation for end-stage heart failure, 2 and 11 years later, respectively. Twenty-year freedom from repeat MV intervention and cumulative survival rate was 92.9% and 91.2%, respectively.

CONCLUSIONS

Long-term follow up of HOCM patients who underwent simultaneous septal myectomy and ALRP showed sustained absence of SAM, attenuation of MI, absence of residual LVOT obstruction and sustained improvement in hemodynamic and functional status.

Robotic Septal Myectomy and Mitral Valve Repair for Idiopathic Hypertrophic Subaortic Stenosis With Systolic Anterior Motion

Combined therapeutic approach with performing mitral valve repair may be necessitated for the treatment of idiopathic hypertrophic subaortic stenosis (IHSS) with systolic anterior motion. This report includes operative technique for combined robotic septal myectomy and mitral valve repair. A 45-year-old man with IHSS was admitted to our center for surgical intervention. The transthoracic echocardiography showed typical asymmetric ventricular hypertrophy. Left ventricle posterior wall thickness was 11 mm, and interventricular septum thickness was 21 mm. Mitral valve leaflets were found to be elongated. Mild-to-severe mitral regurgitation was detected with eccentric mitral jet. Aortic peak gradient was 128 mm Hg. Robotic mitral repair and septal myectomy through left atrial exposure was performed. The anterior leaflet was detached, and the septal muscle in a mass of 1 × 0.7 × 0.5 cm was resected. Next, the anterior leaflet was reattached with continuous suture. The plication of the posterior leaflet with transverse incision was performed to diminish the length of posterior leaflet. After the magic suture for posteromedial commissure was performed, a 34 Medtronic Future ring was implanted for mitral annuloplasty. Postoperative course was uneventful. The patient was discharged on the sixth postoperative day. Combined robotic septal myectomy and mitral valve repair for IHSS with systolic anterior motion may be feasible.

Minimally invasive septal myectomy for the treatment of hypertrophic obstructive cardiomyopathy and intrinsic mitral valve disease

OBJECTIVE

Transaortic left ventricular septal myectomy described by Morrow is a classical procedure for the treatment of systolic anterior motion of the mitral apparatus associated with hypertrophic obstructive cardiomyopathy (HOCM). We aimed to review our results of transmitral septal myectomy and mitral valve repair/replacement in patients with intrinsic mitral valve disease associated with HOCM, operated on through a minimally invasive approach.

METHODS

Between 2005 and 2014, 19 patients [7 men (37%); mean (SD) age, 69.4 (14.5) years] were treated with minimally invasive approach for degenerative mitral regurgitation and HOCM. Preoperative peak left ventricular outflow tract (LVOT) gradient was 66 (24) mm Hg. Severe mitral regurgitation was diagnosed in 16 cases (84%). New York Heart Association functional class III to IV heart failure was present in 13 patients (68%).

RESULTS

Fifteen patients (79%) underwent mitral valve replacement, and four patients (21%) underwent mitral valve repair. Left ventricular outflow tract obstruction was corrected directly in all patients via the mitral valve with septal myectomy/myotomy, avoiding aortotomy in majority of the patients. No significant prolongation of extracorporeal circulation/aortic cross-clamping times was observed (P = 0.41 and P = 0.67, respectively) when compared with a similar population without HOCM. No iatrogenic ventricular septal defect developed in treated patients. No hospital mortality occurred. Resting LVOT gradient reduced at discharge to 13 (22) mm Hg (P = 0.025).

CONCLUSIONS

Transmitral left ventricular septal myectomy in patients with degenerative mitral valve disease is quite a simple, feasible, and effective technique and does not require aortotomy in most cases. It can be performed with low early mortality and satisfactory resolution of LVOT obstruction in a minimally invasive setting.

Long-term benefit of myectomy and anterior mitral leaflet extension in obstructive hypertrophic cardiomyopathy

Severely symptomatic patients with obstructive hypertrophic cardiomyopathy (HC) may benefit from surgical myectomy. In patients with enlarged mitral leaflets and mitral regurgitation, myectomy can be combined with anterior mitral leaflet extension (AMLE) to stiffen the midsegment of the leaflet. The aim of this study was to evaluate the long-term results of myectomy combined with AMLE in patients with obstructive HC. This prospective, observational, single-center cohort study included 98 patients (49 ± 14 years, 37% female) who underwent myectomy combined with AMLE from 1991 to 2012. End points included all-cause mortality and change in clinical and echocardiographic characteristics. Mortality was compared with age- and gender-matched patients with nonobstructive HC and subjects from the general population. Long-term follow-up was 8.3 ± 6.1 years. There was no operative mortality, and New York Heart Association class was reduced from 2.8 ± 0.5 to 1.3 ± 0.5 (p <0.001), left ventricular outflow tract gradient from 93 ± 25 to 9 ± 8 mm Hg (p <0.001), mitral valve regurgitation from grade 2.0 ± 0.9 to 0.5 ± 0.8 (p <0.001), and systolic anterior motion of the mitral valve from grade 2.4 ± 0.9 to 0.1 ± 0.3 (p <0.001). The 1-, 5-, 10-, and 15-year cumulative survival rates were 98%, 92%, 86%, and 83%, respectively, and did not differ from the general population (99%, 97%, 92%, and 85%, respectively, p = 0.3) or patients with nonobstructive HC (98%, 97%, 88%, and 83%, respectively, p = 0.8). In conclusion, in selected patients with obstructive HC, myectomy combined with AMLE is a low-risk surgical procedure. It results in long-term symptom relief and survival similar to the general population.

The role of hemodynamic catheterization in the evaluation of hypertrophic obstructive cardiomyopathy: A case series

Confirmation of the presence and magnitude of left ventricular outflow tract (LVOT) obstruction is a critical component of the evaluation of symptoms in patients with hypertrophic cardiomyopathy (HCM). The presence of LVOT obstruction in patients with severe symptoms refractory to pharmacologic therapy identifies a subgroup of HCM patients who may benefit from septal reduction therapy. Two-dimensional echocardiography with continuous wave Doppler is the main tool for confirming the presence and severity of LVOT obstruction in HCM. However, when uncertainty remains following non-invasive evaluation, invasive hemodynamics studies are required to confirm and quantify LVOT obstruction. In this manuscript we describe a series of 6 cases in which hemodynamic catheterization is instrumental in supplementing non-invasive imaging in the assessment of LVOT obstruction in HCM.

Basic mechanisms of mitral regurgitation

Any structural or functional impairment of the mitral valve (MV) apparatus that exhausts MV tissue redundancy available for leaflet coaptation will result in mitral regurgitation (MR). The mechanism responsible for MV malcoaptation and MR can be dysfunction or structural change of the left ventricle, the papillary muscles, the chordae tendineae, the mitral annulus, and the MV leaflets. The rationale for MV treatment depends on the MR mechanism and therefore it is essential to identify and understand normal and abnormal MV and MV apparatus function.

Myectomy and mitral repair through the left atrium in hypertrophic obstructive cardiomyopathy: the preferred approach for contemporary surgical candidates?

OBJECTIVE

Patients with hypertrophic obstructive cardiomyopathy due to diffuse hypertrophy extending to or below the papillary muscles are poor candidates for alcohol septal ablation and suboptimal candidates for transaortic septal myectomy. In addition, the outflow obstruction is often aggravated by an abnormal mitral valve and subvalvular apparatus.

METHODS

We performed transatrial myectomy in 12 patients with diffuse hypertrophy, who were highly symptomatic despite maximal medical therapy. All had at least moderate mitral regurgitation and systolic anterior motion. The anterior mitral leaflet (AML) was detached from commissure to commissure, allowing an easy myectomy through this AML toward the base of the anterior papillary muscle, with mobility fully restored. The abnormal chordae from the septum to the anterior papillary muscle and AML were divided. The continuity of this AML was restored with augmentation using an autologous pericardial patch. The height of the posterior mitral leaflet was reduced and the repair completed using an oversized annuloplasty ring.

RESULTS

The peak intraventricular gradients decreased spectacularly from 98.8 ± 6.29 to 19.2 ± 13.4 mm Hg (P < .001), and the systolic anterior motion and mitral regurgitation disappeared. One patient died of left ventricular diastolic dysfunction. All other patients left the hospital in New York Heart Association class I or II.

CONCLUSIONS

We believe that this technique is preferable for patients with hypertrophic obstructive cardiomyopathy and diffuse hypertrophy extending to the midportion of the left ventricle or beyond. It results in disappearance of outflow tract gradients and allows correction of the mitral valve abnormality.

Systolic anterior motion of the mitral valve masked by general anesthesia

Systolic anterior motion of the mitral valve is usually associated with hypertrophic obstructive cardiomyopathy that results in left ventricular outflow tract obstruction. This is sometimes treated by volume loading or negative inotropics such as beta blockers. We report a rare case of dynamic systolic anterior motion of the mitral valve, in which a beta blocker did not diminish but anesthetic agents masked intraoperatively. The patient underwent mitral valve replacement, and left ventricular outflow tract obstruction was successfully treated.

A surgical experience of symptomatic sigmoid septum: drastic exacerbation of mitral regurgitation after sufficient ventricular septal myectomy

A 74-year-old woman presented with progressive dyspnea on exertion. Transthoracic echocardiography (TTE) demonstrated significant left ventricular outflow tract (LVOT) obstruction with a pressure gradient of 100 mmHg caused by a sigmoid septum (SS). Mitral regurgitation (MR) of a mild to moderate degree occurred due to systolic anterior motion (SAM) of the anterior mitral leaflet (AML), with no intrinsic mitral valve (MV) abnormality. Myectomy of the hypertrophied septal bulge ameliorated the pressure gradient to 8 mmHg with similar MR. However, just before the sternal closure, hemodynamic status deteriorated drastically to ventricular fibrillation. MR exacerbated to a severe degree with an uncertain etiology; thus, a mechanical prosthetic valve was implanted. The postoperative course was complicated by prolonged mechanical ventilation due to massive pulmonary edema and complete atrioventricular block (CAVB) requiring permanent pacemaker implantation. One year postoperatively, the patient is asymptomatic and TTE revealed no residual pressure gradient with an iatrogenic ventricular septal defect (VSD). This case, the first published surgical experience of SS, may indicate that secondary MR, which is usually relieved by sufficient myectomy in hypertrophic cardiomyopathy (HCM), can exacerbate markedly, and that myectomy might not be advisable in SS. The therapeutic strategy must be considered carefully before embarking on surgical intervention.

Transaortic edge-to-edge mitral valve repair and left ventricular myectomy

Systolic anterior motion of mitral anterior leaflet is a serious clinical condition and it is hard to control medically. Alfieri edge-to-edge repair has been thought one of the useful techniques to improve abnormal anterior systolic motion with hypertrophic obstructive cardiomyopathy. Here, we present a 71-year-old lady who had the left ventricular outflow tract obstruction, severe mitral valve regurgitation with systolic anterior motion. The patient had a history of aortic valve replacement 5 years ago. She was successfully treated with transaortic edge-to-edge mitral valve plasty and myectomy of the left ventricle. Postoperative course was uneventful.

Mitral valve repair is underused in patients with hypertrophic obstructive cardiomyopathy

BACKGROUND

The optimal surgical approach for patients with hypertrophic obstructive cardiomyopathy (HOCM) with concomitant mitral valve (MV) regurgitation has remained controversial. The purpose of this study was to use the largest all-payer database in the United States to examine the strategy most commonly used for the correction of mitral valve pathology in the setting of HOCM.

METHODS

The Nationwide Inpatient Sample (NIS) database was searched from 2005 to 2008 to identify patients with a diagnosis of HOCM (ICD-9-CM code 425.1) who underwent MV repair (ICD-9-CM code 35.12) or replacement (ICD-9-CM codes 35.23 and 35.24). HOCM patients who underwent MV repair and those who underwent MV replacement were compared with respect to baseline characteristics, repair rates, hospital mortality, and length of stay (LOS).

RESULTS

MV repair was performed in 17.2% of cases (219/1255). Repair rates did not show a significantly increasing trend over time (P = .1419). The median LOS was significantly longer for replacement than for repair (11 days versus 7 days, P = .0001). The mortality rate for patients who underwent repair was 0.00%, compared with 11.18% for those who underwent replacement (P < .05).

CONCLUSIONS

The majority of patients with a HOCM diagnosis underwent MV replacement for the correction of MV pathology. Referral to centers with special expertise in treating patients with HOCM may positively affect the operative outcomes of this patient subset.