British randomised controlled trial of AV and VV optimization (“BRAVO”) study: rationale, design, and endpoints

Abstract

BackgroundEchocardiographic optimization of pacemaker settings is the current standard of care for patients treated with cardiac resynchronization therapy. However, the process requires considerable time of expert staff. The BRAVO study is a non-inferiority trial comparing echocardiographic optimization of atrioventricular (AV) and interventricular (VV) delay with an alternative method using non-invasive blood pressure monitoring that can be automated to consume less staff resources.Methods/DesignBRAVO is a multi-centre, randomized, cross-over, non-inferiority trial of 400 patients with a previously implanted cardiac resynchronization device. Patients are randomly allocated to six months in each arm. In the echocardiographic arm, AV delay is optimized using the iterative method and VV delay by maximizing LVOT VTI. In the haemodynamic arm AV and VV delay are optimized using non-invasive blood pressure measured using finger photoplethysmography. At the end of each six month arm, patients undergo the primary outcome measure of objective exercise capacity, quantified as peak oxygen uptake (VO2) on a cardiopulmonary exercise test. Secondary outcome measures are echocardiographic measurement of left ventricular remodelling, quality of life score and N-terminal pro B-type Natriuretic Peptide (NT-pro BNP). The study is scheduled to complete recruitment in December 2013 and to complete follow up in December 2014.DiscussionIf exercise capacity is non-inferior with haemodynamic optimization compared with echocardiographic optimization, it would be proof of concept that haemodynamic optimization is an acceptable alternative which has the potential to be more easily implemented.Trial registrationClinicaltrials.gov NCT01258829

Abnormal diastolic function underlies the different beneficial effects of cardiac resynchronization therapy on ischemic and non-ischemic cardiomyopathy

“…AV delay optimization was conducted using the iterative method. In particular, the optimal AV delay was determined based on the maximum left ventricular filling times at 6 selected AV delays: 180, 160, 140, 120, 100, and 80 ms. VV delay optimization was performed after AV delay optimization; the optimal VV delay was determined using the maximum left ventricular outflow tract velocity time integral at peak velocity (LVOT-VTImax) 12 .…”

Individualized cardiac resynchronization therapy: current status

“…79 Optimization is likely to remain low until a more technically convenient method is available, and since measurement of the CRT effect is of similar size as the variability of the measured echocardiographic parameter, a true effect is difficult to evaluate. Among studies underway to further define this area is the BRAVO study, 80 which is a noninferiority trial, comparing echocardiographic optimization of AV and VV delay with simple, noninvasive blood pressure monitoring.…”

Aktueller Stellenwert der nichtinvasiven koronaren Flussmessung

“…The within subject coefficient of variation (σ w /mean) in log NT-proBNP levels in people with chronic heart failure over 12 months has been reported to be~10%, i.e. around 190 pg/ml [57]. Assuming a log normal distribution of NT-proBNP, with 338 patients we will be able to easily detect an equivalence limit of half the clinically reported difference with >99% power at 5% significance level and have 90% power to detect an equivalence limit of 0.062 log units (i.e.…”