Image-Based Computational Hemodynamics Analysis of Systolic Obstruction in Hypertrophic Cardiomyopathy

Hypertrophic Cardiomyopathy (HCM) is a pathological condition characterized by an abnormal thickening of the myocardium. When affecting the medio-basal portion of the septum, it is named Hypertrophic Obstructive Cardiomyopathy (HOCM) because it induces a flow obstruction in the left ventricular outflow tract. In any type of HCM, the myocardial function can become compromised, possibly resulting in cardiac death. In this study, we investigated with computational analysis the hemodynamics of patients with different types of HCM. The aim was quantifying the effects of this pathology on the intraventricular blood flow and pressure gradients, and providing information potentially useful to guide the indication and the modality of the surgical treatment (septal myectomy). We employed an image-based computational approach, integrating fluid dynamics simulations with geometric and functional data, reconstructed from standard cardiac cine-MRI acquisitions. We showed that with our approach we can better understand the patho-physiological behavior of intraventricular blood flow dynamics due to the abnormal morphological and functional aspect of the left ventricle. The main results of our investigation are: (a) a detailed patient-specific analysis of the blood velocity, pressure and stress distribution associated to HCM; (b) a computation-based classification of patients affected by HCM that can complement the current clinical guidelines for the diagnosis and treatment of HOCM.

Abstract 17189: Radiation-induced Accelerated Multi-valve Disease In A Patient With Subaortic Membrane

A 69-year-old woman with history of right breast cancer status post lumpectomy and radiation (4.2 cGy) 18 months prior, presented with progressive NYHA class III dyspnea. TTE obtained prior to her cancer diagnosis was notable for normal LV size and wall thickness, a subaortic membrane with systolic mean Doppler gradient of 21 mmHg and a mildly thickened mitral valve without significant stenosis or regurgitation. On presentation, TTE was notable for severely increased concentric LV wall thickness (LV mass index 140 g/m 2 ), preserved ejection fraction, increased RV wall thickness, subaortic stenosis with systolic mean Doppler gradient 35 mmHg, moderate-severe aortic regurgitation, thickened mitral valve with posterior leaflet tethering and anterior leaflet override causing severe mitral regurgitation and moderate mitral stenosis (valve area 1.7 cm 2 by pressure half-time). She underwent a surgical intervention with septal myectomy, subaortic membrane resection, aortic root reconstruction, aortic and mitral valve replacement with bioprostheses. She did well post-operatively and had complete resolution of symptoms following cardiac rehabilitation. Radiation-induced valvular heart disease is linked to the total dose of radiation, use of sequential chemotherapy and time since irradiation, with a typical latency of 10-20 years. However, there is paucity of data regarding the influence of these variables in patients with pre-existing valve disease. This case illustrates dramatic acceleration of underlying aortic and mitral valve pathology in a patient with a subaortic membrane, 18 months after radiation. We also noted development of significant concentric LV hypertrophy that was disproportionate to the degree of obstruction across the sub-aortic membrane. Potential candidates for radiation therapy must be carefully screened for pre-existing valve disease, which should warrant increased vigilance and early screening for progressive valve disease.

Early post-septal myectomy outcomes for hypertrophic obstructive cardiomyopathy

Background We aimed to evaluate early outcomes of septal myectomy in patients with hypertrophic cardiomyopathy. Methods We retrospectively analyzed data collected over a 9-year period from 583 patients who underwent septal myectomy for hypertrophic cardiomyopathy at our institution. Results The mean age was 55.7 ± 13.1 years, and 338 (58%) patients were in New York Heart Association class III or IV. There were 11 (1.9%) early deaths, including 3 (0.5%) intraoperative deaths. Early mortality was lowest after isolated septal myectomy (0.8%) and highest after concomitant mitral valve replacement (6.1%). There were 4 (0.7%) and 9 (1.5%) patients with left ventricular wall rupture and ventricular septal defect, respectively, after myectomy. New pacemaker implantation caused by atrioventricular disturbances was required in 29 (5.0%) patients, and was associated with previous alcohol septal ablation (odds ratio 3.34, 95% confidence interval 1.02–11.0, P = 0.047). Left ventricular wall rupture, intraoperative residual (15.5% moderate, 0.3% severe) mitral regurgitation, and pre-discharge residual outflow tract gradient >30 mm Hg (4.6%) occurrences were surgeon-dependent. Conclusions The early results are consistent with example targets reported in the 2020 American College of Cardiology/American Heart Association guidelines for septal reduction therapy outcomes. Septal myectomy safety and efficacy are surgeon-dependent. Previous alcohol septal ablation increases the risk of permanent pacemaker implantation due to postoperative complete atrioventricular block. Therefore, continuous education, mentoring, and learning by doing may play an important role in achieving reasonable septal myectomy safety and efficacy.

Non-pharmaceutical Interventions for Hypertrophic Cardiomyopathy: A Mini Review

Hypertrophic cardiomyopathy is an inherited cardiovascular disease, and 70% of patients have left ventricular outflow tract obstruction. Ventricular septal myectomy has been the gold standard treatment for most patients with refractory symptoms. Due to higher mortality associated with medical facilities with less experience, alcohol septal ablation has been accepted as an alternative to conventional surgical myectomy. It offers lower all-cause in-hospital complications and mortality, which could be potentially more preferable for patients with serious comorbidities. In recent years, radiofrequency ablation, providing another option with reproducibility and a low risk of permanent atrioventricular block, has become an effective invasive treatment to relieve left ventricular outflow tract obstruction. Moreover, substantial progress has been made in gene therapy for hypertrophic cardiomyopathy. The principal objective of this review is to present recent advances in non-pharmaceutical interventions in hypertrophic cardiomyopathy.