Right Ventricular Free Wall Strain: A Predictor of Successful Left Ventricular Assist Device Implantation (2015)

A 54-year-old man with end-stage heart failure due to hypertrophic cardiomyopathy was admitted because of acute hemodynamic deterioration accompanied by disabling dyspnea and asthenia at rest, in association with fluid overload, poor urinary output, and a contextual increase of neurohormonal activation (brain natriuretic peptide level, 4,168 pg/mL). He was already enrolled for heart transplantation at our center.Despite continuing inotropic support (with milrinone) and high-dose diuretics, the patient developed evidence of kidney and liver dysfunction and deteriorated to Class II Interagency Registry for Mechanically Assisted Circulatory Support (Intermacs). The heart team considered him a possible candidate for left ventricular assist device (LVAD) implantation as a bridge to transplantation. Preimplantation echocardiographic evaluation revealed severely impaired left ventricular (LV) systolic function with only mild LV dilation (Fig. 1). Right ventricular (RV) evaluation revealed a fractional area change (34%) below the range of normal value (Fig. 2), low tricuspid annular plane systolic excursion (12 mm) (Fig. 3), and a tissue-Doppler peak systolic velocity (8 cm/s) of the tricuspid annulus, again below the range of normal (Fig. 4).In contrast, the value for RV free-wall longitudinal strain obtained with use of 2-dimensional speckle-tracking echocardiography and EchoPAC PC software (GE Medical Systems; Horten, Norway) was high (−16%), predicting good RV performance after implantation. The 2-dimensional speckle-tracking echocardiograms (Fig. 5) were obtained through offline analysis of grayscale conventional transthoracic images acquired during breath-hold and with a stable electrocardiogram recording. For each figure, 3 consecutive heart cycles were recorded and averaged. The frame rate was set between 60 and 80 frames.The patient successfully underwent LVAD implantation during a short hospital stay.Mechanical circulatory support is a relatively new successful option for patients with end-stage heart failure. According to the most recent Intermacs report,1 the one-year survival rates for patients with LVADs are approaching those for patients who have undergone heart transplantation, which has encouraged the technical improvement of devices and refined the accuracy of candidate selection. Right ventricular failure that requires biventricular assistance or inotropic support for longer than 2 weeks has been a major cause of postimplantation morbidity and death.2 For this reason, the accurate evaluation of RV performance—with the aid of new echocardiographic markers of prognosis—becomes necessary in selecting appropriate patients for LVAD implantation.3Two-dimensional speckle-tracking echocardiography of the RV is a relatively new technique. Because its improved signal-to-noise ratio overcomes most Doppler limits, it is not influenced by angle-dependency and tethering effect.4 Together with the use of traditional echocardiographic results and clinical variables, this new technique greatly strengthens the prognostic marking of candidates for LVAD implantation.5,6For example, RVFWLS can have an additional role in the decision-making for a subset of patients—such as those affected by end-stage hypertrophic cardiomyopathy—in whom the opportunity to implant a mechanical circulatory support device is even more challenging. Our case shows how comprehensive RV evaluation (including RVFWLS) can be used for correct prognostic stratification of candidates for LVAD implantation, when traditional echocardiographic results, considered alone, do not clearly indicate freedom from RV failure after LVAD implantation.