Echocardiographic evaluation of hypertrophic cardiomyopathy: A review of up-to-date knowledge and practical tips

Efficacy and safety of a transaortic approach to midventricular and apical septal myectomy

OBJECTIVE

The study objective was to evaluate the safety and efficacy of a transaortic approach to midventricular and apical septal myectomy in patients with hypertrophic cardiomyopathy with left ventricular outflow tract or midventricular obstruction.

METHODS

From January 2018 to August 2023, 940 patients underwent transaortic septal myectomy at the Cleveland Clinic, of whom 682 (73%) had midventricular or apical resection. Patients who underwent isolated basal myectomies were excluded. Templated operative reports designated septal regions resected as basal (opposition to mitral valve up to the leaflet tips), midventricular (leaflet tips to just beyond the papillary muscle heads), and apical (apical third of the ventricle). Myocardial resection specimen weights, intraventricular gradients, and clinical outcomes were assessed.

RESULTS

Of the 682 patients, 582 (85%) had basal plus midventricular resection and 78 (11%) had basal, midventricular, and apical resection. Mean preoperative intraventricular gradient was 102 ± 41 mm Hg. Median resection weight was 10 g (15th, 85th percentiles: 7, 15), and mean postoperative intraventricular gradient was 16 ± 10 mm Hg, with 625 (96%) patients achieving gradients 36 mm Hg or less. There were no iatrogenic mitral or aortic valve injuries. Permanent pacemaker placement was required in 38 patients (5.6%), of whom 8 (1.2%) had normal preoperative conduction. Operative mortality occurred in 1 patient (0.1%) after an intraoperative ventricular septal defect.

CONCLUSIONS

Most patients undergoing septal myectomy for relief of obstruction required resection beyond the basal septum. With specialized instrumentation, detailed imaging and knowledge of variable septal anatomy, resecting midventricular and apical septal muscle can be safely and effectively achieved through a transaortic approach.

Different mechanisms of mitral regurgitation in hypertrophic cardiomyopathy: A clinical case and literature review

Background

Abnormalities of the mitral valve (MV) apparatus are typical features of hypertrophic cardiomyopathy (HCM). These abnormalities include leaflet elongation, thick leaflets, displacement of papillary muscle, and systolic anterior motion (SAM) of the MV anterior leaflet. Mitral valve chordal rupture associated with HCM is a rare but serious issue capable of change the clinical apparence and the prognosis of the patient.

Case summary

A 57-year-old lady with a history of diabetes, dyslipidemia, and a previous single episode of atrial fibrillation (treated with pharmacological cardioversion), presented to the Emergency Department for worsening dyspnea (New York Heart Association Classification class IV). A trans-thoracic echocardiogram (TTE) showed a significant, septal, and asymmetric left ventricular hypertrophy (basal anteroseptal wall diastolic thickness of 19 mm) with normal left ventricle systolic function. A SAM of AML was evident together with a left ventricular outflow tract gradient of 56 mmHg at rest, rising to 136 mmHg during the Valsalva maneuver. In addition, there was evidence of moderate to severe mitral regurgitation (MR) with an anteriorly directed jet, not very typical of MR related to SAM. A 2D-3D trans-esophageal echocardiogram (2D-3D TEE) revealed a combined MR mechanism based on PML degenerative prolapse with P2-flail from ruptured chordae with related eccentric anteriorly directed regurgitant jet, together with a second regurgitant posteriorly directed jet, related to SAM of AML. The patient underwent MV repair together with septal myectomy, with a good final outcome.

Conclusion

Pre-operative echocardiography (both TTE and 2D-3D TEE) is an essential tool in order to detect different MV abnormalities in patients with HCM. These types of patients should never be treated by septal reduction alone. Surgical MV repair or replacement, together with septal myectomy, may be the preferred approach.