Visualization of transcoronary ablation of septal hypertrophy in patients with hypertrophic obstructive cardiomyopathy: a comparison between cardiac MRI, invasive measurements and echocardiography

Abstract

ObjectiveHypertrophic obstructive cardiomyopathy (HOCM) is treated by surgical myectomy or transcoronary ablation of septal hypertrophy (TASH). The aim of this study was to visualize the feasibility, success and short-term results of TASH on the basis of cardiac MRI (CMR) in comparison with cardiac catheterization and echocardiography.MethodsIn this in vivo study, nine patients with HOCM were treated with TASH. Patients were evaluated by transthoracic echocardiography, invasive cardiac angiography and CMR. Follow-up examinations were carried out after 1, 3 and 12 months. MR imaging was performed on a 1.5-T scanner. All images were processed using the semiautomatic Argus software and were evaluated by an attending thoracic radiologist and cardiologist.ResultsThe echocardiographic pressure gradient (at rest) was 69.3 ± 15.3 mmHg before and 22.1 ± 5.7 mmHg after TASH (P < 0.01, n = 9). The flux acceleration over the aortic valve examined (Vmax) was 5.1 ± 0.6 m/s before and 3.4 ± 0.3 m/s after the TASH procedure (P < 0.05). Also, there was a decrease of septum thickness from 22.0 ± 1.2 to 20.2 ± 1.0 mm (P < 0.05) after 6 ± 3 weeks. The invasively assessed pressure gradient at rest was reduced from 63.7 ± 15.2 to 21.2 ± 11.1 mmHg (P < 0.01) and the post-extrasystolic gradient was reduced from 138.9 ± 12.7 to 45.6 ± 16.5 mmHg (P < 0.01). All differences as well as the quantity of injected ethanol were plotted against the size or amount of scar tissue as assessed in the MRI. There was a statistically significant correlation between the post-extrasystolic gradient decrease and the amount of scar tissue (P = 0.03, r2 = 0.5). In addition, the correlation between the quantity of ethanol and scar tissue area was highly significant (P < 0.01, r2 = 0.6), whereas the values for the gradient deviation (P = 0.10, r2 = 0.34), ΔVmax (P = 0.12, r2 = 0.31), as well as the gradient at rest (P = 0.27, r2 = 0.17) were not significant.ConclusionTASH was consistently effective in reducing the gradient in all patients with HOCM. In contrast to the variables investigated by echocardiography, the invasively measured post-extrasystolic gradient correlated much better with the amount of scar tissue as assessed by CMR. We conclude that the optimal modality to visualize the TASH effect seems to be a combination of CMR and the invasive identification of the post-extrasystolic gradient.

Contrast-enhanced Steady-state Free Precession in the Assessment of Hypertrophic Obstructive Cardiomyopathy after Alcohol Septal Ablation

“…[6][7][8][9][10]19,20 Precontrast SSFP was not feasible for assessing myocardial injuries. We could identify MI in all patients with ceSSFP despite its lower signal ratio than LGE imaging.…”

“…[6][7][8][9][10]14,19 We documented a region of relative hypointensity (Hypo) located adjacent to the left or right ventricular cavity and surrounded by MI as induced by ASA. 9,19 Remote myocardium was defined as septal myocardium that was localized more than one cm distant from MI.…”

“…[6][7][8][9][10] Cine steady- state free precession (SSFP) imaging quantifies the myocardial wall thickness and mass and permits visualization of jet flow crossing the LVOT. 6,10 Late gadolinium enhancement (LGE) imaging is useful to visualize and quantify myocardial infarction (MI) after ASA.…”

“…[6][7][8][9][10] Cine steady- state free precession (SSFP) imaging quantifies the myocardial wall thickness and mass and permits visualization of jet flow crossing the LVOT. 6,10 Late gadolinium enhancement (LGE) imaging is useful to visualize and quantify myocardial infarction (MI) after ASA. 6,8,10 However, multiple breath holds and a side-by-side comparison of cine SSFP and LGE images are required to assess the relationship between LVOT obstruction and ASA-induced MI or microvascular obstruction (MVO).…”

“…6,10 Late gadolinium enhancement (LGE) imaging is useful to visualize and quantify myocardial infarction (MI) after ASA. 6,8,10 However, multiple breath holds and a side-by-side comparison of cine SSFP and LGE images are required to assess the relationship between LVOT obstruction and ASA-induced MI or microvascular obstruction (MVO).…”