ABC | Volume 112, Nº4, April 2019

Original Article Yang Li Risk factors for PTSMA complications Arq Bras Cardiol. 2019; 112(4):432-438 January 2000 and July 2013. Among these 319 patients, 258 met the inclusion criteria for septal reduction therapy with resting left ventricular outflow tract gradient (LVOTG) ≥ 30 mmHg or exercise‑induced LVOTG ≥ 50 mmHg. 9 The diagnostic criteria for HOCM were end-diastolic wall thickness >15 mm, and a non-dilated LV with an ejection fraction (EF) of ≥ 50%. 10 Exclusion criteria were hypertrophy from other causes (n = 17), history of myocardial infarction (n = 10), and prior intervention with PTSMA (n = 7) or septal myectomy (n = 0). Patients with coronary artery disease (CAD) (coronary artery stenosis ≥ 50% evaluated at coronary angiography) without myocardial infarction, mild or moderate valvular heart disease unrelated to HOCM, and patients on antihypertensive therapy were not excluded. Diabetes was defined according to the guidelines. 11 Hypertension was defined as either a systolic or diastolic elevation of blood pressure (>140/90 mmHg) or ongoing antihypertensive therapy. Hypercholesterolemia was defined as a total cholesterol level >5.0 mmol/L, or current treatment with lipid-lowering medications. The present study complied with the Declaration of Helsinki. The Local Ethics Committee of the Liaoning Province Hospital approved the study protocol, and all patients provided an informed consent. Echocardiography Before and during the procedure, and at follow-up, all patients underwent transthoracic echocardiography using a Hewlett-Packard Sonos 1500 (Hewlett-Packard Co., Andover, Massachusetts, USA) echocardiograph with an interfaced 2.5‑MHz transducer. The following parameters were measured: intra-ventricular septum (IVS) thickness, left ventricular posterior wall (LVPW) thickness, and end-systolic and end-diastolic dimensions from the minor axis M-mode of the LV obtained from a 2-dimensional standard left parasternal view. LVOTGwas measured by a continuous-wave Doppler probe positioned at the cardiac apex. EF was automatically calculated. Dobutamine stress echocardiography Dobutamine was administered using an infusion pump at a starting rate of 5 μg·kg -1 ·min -1 , with increments of 5 μg·kg ‑1 ·min -1 every three minutes to a maximum dose of 40 μg·kg -1 ·min -1 if necessary. The stress-induced echocardiography endpoint is the end of the eighth stage of the dobutamine protocol, or following chest pain, dyspnea, a drop in arterial pressure of 20 mmHg or more, and an ST‑segment shift of 1 mm or more. Cardiac catheterization, gradient determination and ablation procedure The right femoral and right radial arteries, as well as the right femoral vein, were cannulated using the standard Judkins technique. After an intravenous bolus of 100-150 U/kg of heparin, a 6F temporary pacemaker lead was placed in the right ventricle, a 6F pigtail catheter was positioned in the left ventricular apex, and a 6F Judkins guiding catheter was placed in the left coronary artery. The resting LVOTG was determined by simultaneous pressure recording. Provocation after premature ventricular contraction caused by the pigtail catheter (Terumo, Japan) was performed if necessary. The adequate septal branch was identified on the coronary angiogram; after that, a 0.014‑inch guide wire (Bmw; Bebi Inc., India) was inserted into the septal branch. Then, an over-the-wire balloon catheter (1.5/2.0/2.5 mm in diameter, 10/20 mm in length; Medtronic, USA) was placed in the proximal part of the septal branch. After balloon inflation at 2-6 atm, the correct balloon position was determined by injection of the contrast medium via the guiding catheter into the left coronary artery, and by injection through the balloon catheter shaft into the septal branch. In order to determine the target septal branch, probationary balloon inflation and/or myocardial contrast echocardiography (MCE) was performed. When sufficient decrease in LVOTG was observed through probationary balloon inflation, the septal branch was identified as the target. MCE was routinely performed according to routine methods. 12 When the target septal branch was determined, after intravenous administration of 5 mg of diamorphine, 1-2 ml of absolute alcohol was slowly injected through the balloon catheter shaft. Ten minutes later, the balloon was deflated and the contrast mediumwas injected via the guiding catheter to ascertain that the septal branch was completely blocked. Patients were monitored in the Coronary Care Unit for three days after removal of the vascular sheaths. After 48 hours, when the patient appeared to have normal cardiac conduction, the temporary pacemaker was removed. If high-grade AV conduction disturbances were observed during the following days, PPM implantation was offered. Patients were discharged and followed at our outpatient clinics. Complications Complications during PTSMA procedures and in-hospital monitoring were registered. The events were acute heart failure, cardiac shock, cardiac death and arrhythmic events (bradycardia, asystole, sustained and non-sustained ventricular tachycardia, and ventricular fibrillation). Coronary artery complications were coronary dissection, coronary perforation, acute myocardial infarction, acute pericardial effusion, pericardial tamponade, and alcohol displacement. Bundle branch block and AV block including advanced heart block, which lead to PPM implantation, were registered. Advanced heart blockwas defined as bifascicular block, and second- or third-degree AV block. Asystole due to third-degree AV block was classified as third-degree AV block (i.e. advanced heart block). Puncture related complications were also included for the final analysis. Patient follow-up Patients were carefully monitored in the Coronary Care Unit for at least three days after the procedure, and back-up pacing was continued via the femoral vein when necessary. In-hospital assessment was performed for all clinical outcomes, including hemorrhagic and vascular complications (femoral artery pseudoaneurysm and puncture hematoma were also included for analysis). After discharge, monthly clinical follow-up examinations were conducted on an outpatient basis, in order to monitor the occurrence of adverse events. Examinations through catheterization were not routinely performed, and were only conducted when residual or recurrent symptoms were observed after discharge. PTSMA was repeated when necessary. A failed outcome after PTSMA was defined as the need for 433