Innovation in surgical treatment of hypertrophic obstructive cardiomyopathy in children

Hypertrophic cardiomyopathy is the second most common cardiomyopathy affecting children and adolescents and is the main cause of sudden death of young athletes. The natural prognosis of children with severe hypertrophic obstructive cardiomyopathy is not optimistic, and it is not uncommon for children with hypertrophic obstructive cardiomyopathy who do not respond to medication. Surgical treatment is often the only solution. Conventional surgical methods in the past include classic or modified extended Morrow operation, classic or modified Konno operation, and Ross-Konno operation. In recent years, with the development of minimally invasive surgery, various minimally invasive surgical methods have emerged endlessly. Because the incision of minimally invasive cardiac surgery is significantly smaller than that of traditional surgery, it causes less trauma, recovers quickly after surgery, and has the advantage of no difference in surgical effect compared with traditional median sternotomy. Tally endoscopic transmitral myectomy, RTM, minimally right thoracotomy, and other surgical methods have achieved encouraging results in adults and some older children with hypertrophic obstructive cardiomyopathy. The appearance of transapical beating-heart septectomy has brought the treatment of hypertrophic obstructive cardiomyopathy from the era of cardiopulmonary bypass and cardiac arrest to a new era of minimally invasive beating-heart surgery. In the past, there were few articles about the treatment of children with hypertrophic obstructive cardiomyopathy. This article reviewed the new progress and prognosis of surgical treatment of children with hypertrophic obstructive cardiomyopathy at home and abroad.

Minimally invasive right infra-axillary thoracotomy for transaortic septal myectomy

Extended left ventricular septal myectomy remains the gold standard for the treatment of hypertrophic obstructive cardiomyopathy (HOCM) with refractory symptoms. On the basis of traditional modified transaortic Morrow myectomy, we innovatively performed a minimally invasive, video-assisted single-port thoracotomy through the right infra-axillary region. Our procedure can provide good visualization of the left ventricular outflow tract and hypertrophic ventricular septum for accurate resection. It also ensures optimal exposure of the mitral valve in the presence of complex mitral subvalvular structures.

Robotic Mitral Valve Surgery with Intracardiac Ultrasound Guided Septal Myectomy

Hypertrophic obstructive cardiomyopathy requires surgical myectomy when heart failure symptoms persist despite best medical therapy. Minimally invasively myectomy with robotic surgery can be performed in experienced centers allowing for surgical correction of accompanying mitral valve pathologies. The extent of myectomy is important to relieve left ventricular outflow tract obstruction while care should be taken to prevent iatrogenic ventricular septal defects or heart blocks caused by excessive removal of septal tissue. We report the use of intracardiac ultrasound during robotic surgery to intraoperatively assess the myocardium before and after myectomy to increase the safety of this procedure. Hypertrophic obstructive cardiomyopathy (HOCM) is a genetic myocardial disease characterized by thickened myocardium and obstruction of the left ventricular outflow tract (LVOT). ¹ Patients with symptoms of heart failure resistant to drug treatment are candidates for surgical septal myectomy. Conventionally performed through a midline sternotomy, septal myectomy can be carried out via transapical, transaortic, or transmitral approaches. The transmitral approach allows surgical treatment of the concomitant mitral valve pathology through a left atriotomy. Robotic septal myectomy can be performed in experienced centers with results comparable to the classical sternotomy approach with the added benefits of minimally invasive surgery. ² Excessive removal of septal tissue can result in a heart block or a ventricular septal defect while an inadequate myectomy can leave a high gradient in the LVOT. Intracardiac ultrasound can assist the surgeon in performing a safe and adequate myectomy. We describe our technique for intracardiac ultrasound guided robotic septal myectomy in a patient with HOCM and infective endocarditis.

Videoscope-assisted transaortic myectomy in patients with hypertrophic cardiomyopathy with complex left ventricular anatomy

BACKGROUND

The transaortic approach is the most common method of septal myectomy. However, difficulties arise due to a limited view of the surgical field. Here, we report our experience with videoscope-assisted transaortic myectomy.

METHODS

We reviewed myectomy operations that were performed between July 2015 and June 2019 at Chung-Ang University Hospital, Seoul, South Korea. Patients who previously had cardiac surgery, alcohol septal ablation, or concomitant disease which required combined surgery, were excluded. Among the 21 patients included, 10 patients underwent videoscope-assisted transaortic myectomy (VA group), and 11 patients underwent myectomy in a conventional manner (CO group). The preoperative data, echocardiographic images, operative records, and postoperative outcomes of these patients were reviewed.

RESULTS

There were no differences in baseline characteristics between groups VA and CO. The main indications for videoscope-assisted transaortic myectomy in group VA were midventricular septal muscle resection (70%), abnormal papillary muscle resection (40%), and abnormal chordal connection resection (30%). Eight (80%) patients had multiple indications for videoscope-assisted transaortic myectomy. There was no surgical mortality in either group. Postoperative patients showed less than moderate mitral regurgitation and a New York Heart Association class either III or IV. There were no differences in hospital days (9.5 vs. 12.0 days; p = .383), nor postoperative pressure gradient (14 vs. 15 mmHg; p > .99).

CONCLUSIONS

Videoscope-assisted transaortic myectomy is an effective surgical technique in selective hypertrophic cardiomyopathy patients with complex intraventricular anatomy, diffuse hypertrophy, and midventricular obstruction.

Transapical Septal Myectomy for Hypertrophic Cardiomyopathy With Midventricular Obstruction

BACKGROUND

Midventricular obstruction (MVO) is an uncommon variant of hypertrophic cardiomyopathy (HCM). In patients receiving septal myectomy for HCM, failure to recognize the concurrent MVO in the context of basal septum thickening can lead to inadequate excision and residual gradient. In this report, we detail the operative outcomes of MVO with and without coexistent basal septal hypertrophy.

METHODS

From February 1997 through September 2018, 196 patients underwent midventricular myectomy. Medical records and follow-up databases were reviewed to obtain patient characteristics and perioperative features.

RESULTS

At baseline, 156 patients (80%) were in New York Heart Association Functional Classification III/IV. Obstruction was isolated to the midventricle in 80 patients, and 63 (79%) were treated by isolated transapical myectomy. The remaining 116 patients had intraventricular obstruction at both subaortic and midcavity levels; in 108 (93%), a combined transaortic and transapical approach was adopted to achieve complete relief of the obstruction. After septal myectomy, the resting peak instantaneous gradient decreased from a median 48 mm Hg (interquartile range [IQR], 23-77 mm Hg) preoperatively to 8 mm Hg (IQR, 0-19 mm Hg) before hospital dismissal. Median follow-up was 2.9 years (IQR, 0.7-5.0 years), and the estimated 1-, 5-, and 10-year survivals were 99%, 98%, and 90%, respectively. There were no late complications attributable to the transapical incision.

CONCLUSIONS

Transapical exposure is a safe and effective approach for relief of midventricular obstruction, and hemodynamic results are similar to those achieved by standard myectomy for subaortic obstruction. The technique can be combined with transaortic myectomy for patients with left ventricular outflow obstruction at both levels.

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.