Effects of Echo-optimization of Left Ventricular Assist Devices on Functional Capacity (VAFRACT) (VAFRACT)

The Effects of Echo-optimization of Left Ventricular Assist Devices on Functional Capacity, a RAndomized Controlled Trial (VAFRACT)

After the implantation of a left ventricular assist device (LVAD), many patients continue to experience exercise intolerance. LVAD echo guided optimization (EO) determines a more favorable hemodynamic profile and could provide an improvement on functional capacity (FC). VAFRACT is a prospective randomized trial to evaluate the additional benefit of an EO approach on FC, measured by cardiopulmonary exercise test (CPET), in LVAD optimization free population.

The use of Left Ventricular Assist Devices (LVAD) is a viable therapeutic option to improve survival and quality of life of patients with advanced and refractory heart failure (HF). However, after the implantation of an LVAD, patients' functional capacity (FC) is still reduced with maximum oxygen uptake (VO2 peak) values calculated at the cardiopulmonary exercise test (CPET) ranging from 11 to 20 ml/kg/min. LVAD echo guided optimization (EO) determines a more favorable hemodynamic profile, in particular for the right ventricle, and could provide an improvement on FC. VAFRACT is a prospective randomized trial to evaluate the additional benefit of an EO approach on FC, measured by CPET in LVAD optimization free population. The optimal device speed is defined as the one that allows an intermittent aortic valve opening and a neutral position of the interventricular septum without increasing aortic or tricuspid regurgitation associated or not to a dilatation of the right ventricle (RV). In this condition it is reasonable to expect a more favorable hemodynamic profile for the RV and a better response in terms of functional capacity. Subjects studied are HF patients supported with a continuous-flow LVAD: HeartMate II (Thoratec Inc., Pleasanton, CA) and HeartMate 3 (HM 3, Abbott, North Chicago, IL). Patients are recruited from our Day Hospital of the Cardiac Surgery Department at the University Hospital of Verona.

left ventricular assist device, echo-optimization, functional capacity, cardiopulmonary exercise test

Patients underwent LVAD echo-optimization; the optimal device speed is confirmed at the end of procedure.

Patients underwent LVAD echo-optimization, but the optimal device speed is not confirmed at the end of procedure.

LVAD echo-optimization consists of routine comprehensive transthoracic echocardiography at the baseline speed setting, followed by stepwise incremental adjustments to the LVAD speed (revolutions per minute: rpm), with collection of prespecified echocardiographic parameters at each new speed (eg, left ventricle end-diastolic diameter, interventricular septal position, aortic valve opening frequency/duration, tricuspid and/or mitral regurgitation severity). The optimal velocity is defined as the one that allows an intermittent aortic valve opening and a neutral position of the interventricular septum without increasing aortic or tricuspid regurgitation, associated or not to a dilatation of the right ventricle. The recommended speed range varies according to the indications given in the data sheet for each specific device.

Rate of hospitalizations for: device thrombosis, hemorrhagic events, infections, right heart failure, arrhythmias.

Changes in quality of life perceived by EuroQoL (quality of life) Scale. It is an instrument which evaluates the quality of life measuring with one question: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. The answers given to these question (1 = no problems; 2 = some problems; 3 = extreme problems) are converted into EQ-5D index, an utility scores anchored at 0 for death and 1 for perfect health. The EQ-5D questionnaire also includes a Visual Analog Scale (VAS), by which respondents can report their perceived health status with a grade ranging from 0 (the worst possible health status) to 100 (the best possible health status).

Inclusion Criteria: at least 3 months after LVAD implantation; compliance to the required follow-up schedule; age 18 or above or of legal age to give informed consent specific to state and national laws. Exclusion Criteria: distance of less than 150 meters on the six-minute walk test (6MWT) or impossibility to perform CPET recent finding of any major device-related complication (sepsis, thrombosis …).