Effects of percutaneous transluminal septal myocardial ablation for obstructive hypertrophic cardiomyopathy on systolic and diastolic left ventricular function assessed by pressure-volume loops

Short- and long-term outcome after alcohol septal ablation in obstructive hypertrophic cardiomyopathy: Experience of a reference center

INTRODUCTION

In obstructive hypertrophic cardiomyopathy (HCM), alcohol septal ablation (ASA) can lead to gradient reduction and symptom improvement. We aimed to assess the efficacy and safety of ASA in a long-term outcome study.

METHODS

We analyzed patients who underwent ASA over a seven-year period in a tertiary center. The primary echocardiographic endpoint was >50% reduction in left ventricular outflow tract (LVOT) gradient within a year of the procedure. The primary clinical endpoints were improvement in functional capacity and a combined endpoint of cardiac death and rehospitalization for cardiac cause. The follow-up period was 4.17±2.13 years.

RESULTS

A total of 80 patients, mean age 63.9±12.3 years, 30.0% male, were analyzed. Baseline LVOT gradient was 96.3±34.6 mmHg and interventricular septal thickness was 21.6±3.1 mm. Minor complications were observed in 6.3% and major complications in 2.5%, and 8.8% received a permanent pacemaker. The primary echocardiographic endpoint was achieved by 85.7%. At three-month follow-up, LVOT gradient was 25.8±26.0 mmHg in the successful procedure group, compared to 69.2±35.6 mmHg in the other patients (p=0.001). At six months, LVOT gradient was 27.1±27.4 vs. 58.2±16.6 mmHg (p=0.024). Among 74 patients in NYHA class III/IV before the procedure, 57 (77%) improved to NHYA class I/II. The combined primary clinical endpoint (cardiac death and rehospitalization for cardiac cause) was observed in 27.5% (n=22). In the unsuccessful group, the combined endpoint was observed in 54.5%, compared to only 22.7% in the successful group. Only two patients died of cardiac causes.

CONCLUSION

ASA is a safe procedure with a high success rate. Patients who achieved significant reductions in LVOT gradient suffered less cardiac death and rehospitalization for cardiac cause.

Effects of alcohol septal ablation on left ventricular diastolic filling patterns in obstructive hypertrophic cardiomyopathy

Alcohol septal ablation (ASA) has been shown to improve left ventricular (LV) diastolic function in patients with obstructive hypertrophic cardiomyopathy (HCM). However, its beneficial effect on diastolic function assessed by cardiac magnetic resonance (CMR) has not been reported. We investigated the mid-term changes of diastolic function by CMR combined with echocardiography in HCM patients after ASA at a median of 14-month follow-up. CMR parameters of diastolic function including peak filling rate (PFR), and time to peak filling rate (TPFR) were evaluated in 43 patients (aged 48 ± 9 years). LV diastolic function improved significantly measured by echocardiography with the decrease in ratio of transmitral early LV filling velocity (E) to early diastolic mitral lateral annular velocity (E') (14.20 ± 1.17 to 11.58 ± 1.16, p < 0.001) and E-wave deceleration time (194.04 ± 19.30 to 168.45 ± 12.58 ms, p < 0.001). PFR increased significantly with associated decrease in TPFR after ASA (both p < 0.001) at follow-up. Furthermore, patients with larger decrease in LVOT gradients had a greater improvement of LV diastolic function, as measured by the reduction of E/E' (p < 0.001) and increase of PFR (p < 0.001). In conclusion, this study demonstrated that successful ASA results in both echocardiographic and CMR indices of diastolic function improvement after ASA at 14-month follow-up. ASA therapy can significantly reduce LVOT gradient and mitral regurgitation, both of which may contribute to the improvement of diastolic function.

Biventricular reverse remodeling after successful alcohol septal ablation for obstructive hypertrophic cardiomyopathy

The aim of the present study was to investigate the long-term effects of alcohol septal ablation (ASA) on left ventricular (LV) and right ventricular (RV) remodeling in patients with obstructive hypertrophic cardiomyopathy (HC) using cardiovascular magnetic resonance (CMR). CMR was performed at baseline and 16 months after ASA in 38 patients with obstructive HC (mean age 48 ± 9 years) despite optimal medical treatment. ASA resulted in significant reductions of LV outflow tract gradient (mean 89 ± 22 vs 24 ± 12 mm Hg, p <0.001) and improvements in New York Heart Association functional class (p <0.001) during the follow-up period. LV remote mass and septal mass decreased from 98.34 ± 37.02 to 84.23 ± 34.71 g and from 77.56 ± 16.40 to 68.43 ± 14.02 g, respectively (p <0.001 for both) at 16-month follow-up. There were significant reductions of RV mass (mean 53.69 ± 7.12 vs 47.49 ± 6.17 g, p <0.001) and improvements in RV end-diastolic volume (mean 110.58 ± 22.47 vs 124.22 ± 24.17 ml, p <0.001) and the RV ejection fraction (p <0.001) during 16-month follow-up. Linear regression analysis showed that LV outflow tract gradient reduction was correlated significantly with LV remote mass reduction (r = 0.475, p = 0.003) and RV mass reduction (r = 0.535, p = 0.001) at 16-month follow-up. In conclusion, successful ASA can lead to positive biventricular reverse remodeling, showing significant reductions of RV and LV mass as well as increased RV and LV end-diastolic volumes during follow-up.

Heart rate-dependent left ventricular diastolic function in patients with and without heart failure

BACKGROUND

Chronic heart rate (HR) reduction in the treatment of heart failure (HF) with systolic dysfunction is beneficial, but the immediate mechanical advantages or disadvantages of altering HR are incompletely understood. We examined the effects of increasing HR on early and late diastole in humans with and without HF.

METHODS AND RESULTS

We studied force-interval relationships of the left ventricle (LV) in 11 HF patients and 14 control subjects. HR was controlled by right atrial pacing, and LV pressure was recorded by a micromanometer-tipped catheter. The time constant of isovolumic relaxation (tau) was calculated, and simultaneous sonographic images were analyzed for LV volumes. The end-diastolic pressure-volume relationship (EDPVR) was analyzed with the use of a single-beat method. Tau was shortened in response to increasing HR in both groups; the slope of this relationship was steeper in HF than in control subjects. The predicted volume at a theoretic pressure of 0 mm Hg (V30) increased at higher HRs compared with baseline, shifting the predicted EDPVR compliance curve to the right in HF patients but not in control subjects.

CONCLUSIONS

In HF, changes in HR affect early relaxation and diastolic compliance to a greater extent than in control subjects. Our study reinforces current recommendations for HR-lowering drug treatment in HF.

Evaluation of left ventricular myocardial perfusion and function using gated SPECT in patients with hypertrophic obstruction cardiomyopathy following percutaneous transluminal septal myocardial ablation

OBJECTIVE

This study was designed to evaluate the left ventricular myocardial perfusion and function in hypertrophic obstruction cardiomyopathy patients following percutaneous transluminal septal myocardial ablation (PTSMA) using rest single-photon emission computed tomography (SPECT) myocardial perfusion imaging.

PATIENTS AND METHODS

Thirty-five patients (24 men and 11 women, 48±11 years old) with hypertrophic obstruction cardiomyopathy underwent rest-gated Tc-MIBI SPECT imaging 4±10 days before (baseline) and 4.7±1.0 days (short-term) and 15.5±8.2 months (mid-term) after PTSMA. Semiquantitative and QGS quantitative evaluations of perfusion and function were carried out in 17 left ventricular segments.

RESULTS

Myocardial perfusion of the septum following PTSMA was significantly reduced compared with baseline in all patients (P<0.05), but the myocardial perfusion in the basal septum was significantly higher at mid-term compared with short-term following PTSMA (P<0.05). Left ventricular ejection fraction was significantly decreased following PTSMA (P<0.05). Regional wall motion assessed in the basal anterior, basal septum, and basal inferior areas following PTSMA was significantly reduced compared with baseline (P<0.05), and wall thickening of the interventricular septum was decreased following PTSMA (P<0.05).

CONCLUSION

Rest-gated SPECT imaging can be used to assess left ventricular myocardial perfusion and function and to investigate the efficacy of PTSMA during follow-up.

Effects of alcohol septal ablation on coronary microvascular function and myocardial energetics in hypertrophic obstructive cardiomyopathy

This study investigated the effects of alcohol septal ablation (ASA) on microcirculatory function and myocardial energetics in patients with hypertrophic cardiomyopathy (HCM) and left ventricular outflow tract (LVOT) obstruction. In 15 HCM patients who underwent ASA, echocardiography was performed before and 6 mo after the procedure to assess the LVOT gradient (LVOTG). Additionally, [(15)O]water PET was performed to obtain resting myocardial blood flow (MBF) and coronary vasodilator reserve (CVR). Changes in LV mass (LVM) and volumes were assessed by cardiovascular magnetic resonance imaging. Myocardial oxygen consumption (MVo(2)) was evaluated by [(11)C]acetate PET in a subset of seven patients to calculate myocardial external efficiency (MEE). After ASA, peak LVOTG decreased from 41 ± 32 to 23 ± 19 mmHg (P = 0.04), as well as LVM (215 ± 74 to 169 ± 63 g; P < 0.001). MBF remained unchanged (0.94 ± 0.23 to 0.98 ± 0.15 ml·min(-1)·g(-1); P = 0.45), whereas CVR increased (2.55 ± 1.23 to 3.05 ± 1.24; P = 0.05). Preoperatively, the endo-to-epicardial MBF ratio was lower during hyperemia compared with rest (0.80 ± 0.18 vs. 1.18 ± 0.15; P < 0.001). After ASA, the endo-to-epicardial hyperemic (h)MBF ratio increased to 1.03 ± 0.26 (P = 0.02). ΔCVR was correlated to ΔLVOTG (r = -0.82; P < 0.001) and ΔLVM (r = -0.54; P = 0.04). MEE increased from 15 ± 6 to 20 ± 9% (P = 0.04). Coronary microvascular dysfunction in obstructive HCM is at least in part reversible by relief of LVOT obstruction. After ASA, hMBF and CVR increased predominantly in the subendocardium. The improvement in CVR was closely correlated to the absolute reduction in peak LVOTG, suggesting a pronounced effect of LV loading conditions on microvascular function of the subendocardium. Furthermore, ASA has favorable effects on myocardial energetics.

A decade of percutaneous septal ablation in hypertrophic cardiomyopathy

Percutaneous septal ablation has emerged as a less invasive treatment of symptomatic patients with hypertrophic obstructive cardiomyopathy (HOCM). In the past decade, the availability of this sophisticated technique has revived the interest of cardiologists in left ventricular outflow tract obstruction, which led to the recognition that most patients with HCM have the obstructive type. Follow-up studies have already shown the safety and efficacy of the procedure, which offers symptomatic relief in most patients. Long-term survival is comparable to historical reports after surgical myectomy. Complications are rare and can be further reduced with increased experience of the operators, and the theoretical concern for possible ventricular arrhythmogenicity of the myocardial scar has not been documented by the existing data. Although there are still no randomized trials, percutaneous septal ablation is undeniably a viable alternative for patients with HOCM.

Determinants of myocardial energetics and efficiency in symptomatic hypertrophic cardiomyopathy

PURPOSE

Next to hypertrophy, hypertrophic cardiomyopathy (HCM) is characterized by alterations in myocardial energetics. A small number of studies have shown that myocardial external efficiency (MEE), defined by external work (EW) in relation to myocardial oxidative metabolism (MVO(2)), is reduced. The present study was conducted to identify determinants of MEE in patients with HCM by use of dynamic positron emission tomography (PET) and cardiovascular magnetic resonance imaging (CMR).

METHODS

Twenty patients with HCM (12 men, mean age: 55.2 + or - 13.9 years) and 11 healthy controls (7 men, mean age: 48.1 + or - 10 years) were studied with [(11)C]acetate PET to assess MVO(2). CMR was performed to determine left ventricular (LV) volumes and mass (LVM). Univariate and multivariate analyses were employed to determine independent predictors of myocardial efficiency.

RESULTS

Between study groups, MVO(2) (controls: 0.12 + or - 0.04 ml x min(-1) x g(-1), HCM: 0.13 + or - 0.05 ml x min(-1) x g(-1), p = 0.64) and EW (controls: 9,139 + or - 2,484 mmHg x ml, HCM: 9,368 + or - 2,907 mmHg x ml, p = 0.83) were comparable, whereas LVM was significantly higher (controls: 99 + or - 21 g, HCM: 200 + or - 76 g, p < 0.001) and MEE was decreased in HCM patients (controls: 35 + or - 8%, HCM: 21 + or - 10%, p < 0.001). MEE was related to stroke volume (SV), LV outflow tract gradient, NH(2)-terminal pro-brain natriuretic peptide (NT-proBNP) and serum free fatty acid levels (all p < 0.05). Multivariate analysis revealed that SV (ss = 0.74, p < 0.001) and LVM (ss = -0.43, p = 0.013) were independently related to MEE.

CONCLUSION

HCM is characterized by unaltered MVO(2), impaired EW generation per gram of myocardial tissue and subsequent deteriorated myocardial efficiency. Mechanical external efficiency could independently be predicted by SV and LVM.