title: Effects of alcohol septal ablation on coronary microvascular function and myocardial energetics in hypertrophic obstructive cardiomyopathy.
abstract: 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.
authors.affiliation: Dept. of Cardiology, 5F, VU Univ. Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
authors.forename: Stefan A J
authors.initials: SA
authors.lastname: Timmer
authors.forename: Paul
authors.initials: P
authors.lastname: Knaapen
authors.forename: Tjeerd
authors.initials: T
authors.lastname: Germans
authors.forename: Pieter A
authors.initials: PA
authors.lastname: Dijkmans
authors.forename: Mark
authors.initials: M
authors.lastname: Lubberink
authors.forename: Jurrien M
authors.initials: JM
authors.lastname: Ten Berg
authors.forename: Folkert J
authors.initials: FJ
authors.lastname: Ten Cate
authors.forename: Iris K
authors.initials: IK
authors.lastname: Rüssel
authors.forename: Marco J W
authors.initials: MJ
authors.lastname: Götte
authors.forename: Adriaan A
authors.initials: AA
authors.lastname: Lammertsma
authors.forename: Albert C
authors.initials: AC
authors.lastname: van Rossum
mesh_terms: D055011:Ablation Techniques; D000465:Algorithms; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000601:surgery*; D003326:Coronary Circulation; D004452:Echocardiography; D004699:Endocardium / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology*; D000431:Ethanol; D005260:Female; D006346:Heart Septum / Q000601:surgery*; D006439:Hemodynamics; D006801:Humans; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption; D010496:Pericardium / Q000502:physiology; D049268:Positron-Emission Tomography; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000378:metabolism / Q000601:surgery; D016277:Ventricular Function, Left
chemical_list: D000431:Ethanol