Myectomy plus Alfieri technique for outflow tract obstruction in hypertrophic cardiomyopathy

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.

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.

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.

Clinical utility of cardiovascular magnetic resonance in hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is characterized by substantial genetic and phenotypic heterogeneity, leading to considerable diversity in clinical course including the most common cause of sudden death in young people and a determinant of heart failure symptoms in patients of any age. Traditionally, two-dimensional echocardiography has been the most reliable method for establishing a clinical diagnosis of HCM. However, cardiovascular magnetic resonance (CMR), with its high spatial resolution and tomographic imaging capability, has emerged as a technique particularly well suited to characterize the diverse phenotypic expression of this complex disease. For example, CMR is often superior to echocardiography for HCM diagnosis, by identifying areas of segmental hypertrophy (ie., anterolateral wall or apex) not reliably visualized by echocardiography (or underestimated in terms of extent). High-risk HCM patient subgroups identified with CMR include those with thin-walled scarred LV apical aneurysms (which prior to CMR imaging in HCM remained largely undetected), end-stage systolic dysfunction, and massive LV hypertrophy. CMR observations also suggest that the cardiomyopathic process in HCM is more diffuse than previously regarded, extending beyond the LV myocardium to include thickening of the right ventricular wall as well as substantial morphologic diversity with regard to papillary muscles and mitral valve. These findings have implications for management strategies in patients undergoing invasive septal reduction therapy. Among HCM family members, CMR has identified unique phenotypic markers of affected genetic status in the absence of LV hypertrophy including: myocardial crypts, elongated mitral valve leaflets and late gadolinium enhancement. The unique capability of contrast-enhanced CMR with late gadolinium enhancement to identify myocardial fibrosis has raised the expectation that this may represent a novel marker, which may enhance risk stratification. At this time, late gadolinium enhancement appears to be an important determinant of adverse LV remodeling associated with systolic dysfunction. However, the predictive significance of LGE for sudden death is incompletely resolved and ultimately future large prospective studies may provide greater insights into this issue. These observations underscore an important role for CMR in the contemporary assessment of patients with HCM, providing important information impacting diagnosis and clinical management strategies.

Progress in perioperative echocardiography: focus on safety, clinical outcomes, 3-dimensional imaging, and education

Gastric decompression with an orogastric tube after anesthetic induction does not appear to enhance image quality for routine cases. The insertion of a transesophageal echocardiographic (TEE) probe can cause significant upper-airway trauma, which can be minimized with rigid laryngoscopy. Limited TEE imaging without transgastric views appears to be safe and clinically adequate in patients with advanced liver disease and esophageal varices. Although esophagogastric perforation because of transesophageal echocardiography is rare, the risk is significantly higher with advanced age and female sex. The echocardiographic assessment of right ventricular function and left ventricular diastolic function can improve the prediction of atrial arrhythmias after elective lung resection. Furthermore, asymptomatic left ventricular systolic or diastolic dysfunction is an independent predictor of cardiovascular mortality and morbidity after open vascular surgery. Advances in 3D echocardiography have shown that hypertrophic cardiomyopathy frequently is associated with changes in the mitral valve complex that predispose to left ventricular outflow tract obstruction. Furthermore, 3D imaging of the mitral apparatus has highlighted the importance of the annular saddle shape and the anatomic variability in ischemic mitral regurgitation. Education in perioperative echocardiography is experiencing high demand that can be satisfied partially with simulators and Internet-based educational activities. These modalities will aid in the dissemination of echocardiography through perioperative practice.