Right ventricular dysfunction in left ventricular assist device candidates: is it time to change our prospective?

The use of left ventricular assist devices (LVAD) has significantly increased in the last years, trying to offer a therapeutic alternative to heart transplantation, in light also to the significant heart donor shortage compared to the growing advanced heart failure population. Despite technological improvements in the devices, LVAD-related mortality is still fairly high, with right heart failure being one of the predominant predictors. Therefore, many efforts have been made toward a thorough right ventricular (RV) evaluation prior to LVAD implant, considering clinical, laboratory, echocardiographic, and invasive hemodynamic parameters. However, there is high heterogeneity regarding both which predictor is the strongest as well as the relative cut-off values, and a consensus has not been reached yet, increasing the risk of facing patients in which the distinction between good or poor RV function cannot be surely reached. In parallel, due to technological development and availability of mechanical circulatory support of the RV, LVADs are being considered even in patients with suboptimal RV function. The aim of our review is to analyze the current evidence regarding the role of RV function prior to LVAD and its evaluation, pointing out the extreme variability in parameters that are currently assessed and future prospective regarding new diagnostic tools. Finally, we attempt to gather the available information on the therapeutic strategies to use in the peri-operative phase, in order to reduce the incidence of RV failure, especially in patients in which the preoperative evaluation highlighted some conflicting results with regard to ventricular function.

Systematic Left Ventricular Assist Device Implant Eligibility with Non-Invasive Assessment: The SIENA Protocol.

In patients with end-stage left ventricular (LV) heart failure who receive LV assist device (LVAD) implantation, right ventricular (RV) failure represents a possible critical complication that heavily affects morbidity and mortality. Several clinical, laboratory, hemodynamic, and echocardiographic variables have been found to be associated with RV failure occurrence after surgery. Different models and risk scores have been proposed, with poor results. No accordance has ever been reached about RV pre-operative evaluation, and time has come to introduce a standardized systematic protocol for LVAD suitability assessment according to RV function. We analyzed imaging parameters associated with LVAD implantation-related RV failure, in order to identify the minimum number for pre-operative reliable prediction of post-operative RV failure. A few echocardiographic parameters have been identified as the most reliable, or promising, and reproducible tools in this field: free-wall RV longitudinal strain, RV fractional area change, RV sphericity index, and RV ejection fraction with 3D-echocardiography. We propose the Systematic LVAD Implant Eligibility with Non-invasive Assessment protocol-the SIENA protocol-as a new and simple way of pre-operative evaluation of patients candidates to LVAD implantation.

Right atrial speckle tracking analysis as a novel noninvasive method for pulmonary hemodynamics assessment in patients with chronic systolic heart failure.

BACKGROUND: The right atrium (RA) plays multiple roles in the cardiac cycle. The reservoir phase of the RA is a dynamic rather than a static phase of cardiac cycle and RA deformation is dependent on pulmonary pressures exerted on the right ventricle and, therefore, backwards on the RA. The purpose of this study was to assess the accuracy and the clinical applicability of the speckle tracking echocardiography (STE) evaluation of the RA in predicting the invasive systolic pulmonary artery pressure (SPAP) in patients with systolic heart failure (HF) undergoing right heart catheterization (RHC). METHODS: Thirty-one hemodynamically stable, in-clinic HF patients who were undergoing RHC were included. Doppler echocardiography and RHC catheterization were simultaneously performed. Echocardiographic measures and STE where obtained as peak atrial longitudinal strain (PALS), RA strain rate, and time to peak longitudinal strain (TPLS). RA PALS was inversely correlated with invasively assessed SPAP (r =-0.81; P < 0.001) while RA strain directly correlated with SPAP (r = 0.82; P < 0.001). RA PALS and strain rate retained this correlation even after nitroprusside challenge test (r =-0.81; P < 0.001 and r = 0.91; P < 0.001, respectively). Area under the curve optimal cutoffs for predicting the SPAP > 50 mmHg were for RA PALS 10.3% (AUC:0.93, sensitivity: 100%, specificity: 78%). CONCLUSION: RA STE showed a significant correlation with pulmonary pressure. RA assessment with STE can predict pulmonary artery hypertension in HF patients. This result is consistent with nitroprusside challenge test. Although RA STE is not routinely used, its evaluation may implement right heart evaluation in HF patients.

Favorable short-term outcome of transplanted hearts selected from marginal donors by pharmacological stress echocardiography.

BACKGROUND: Because of the shortage of donor hearts, the criteria for acceptance have been considerably expanded. Abnormal results on pharmacologic stress echocardiography are associated with significant coronary artery disease and/or occult cardiomyopathy on verification by cardiac autopsy. The aim of this study was to establish the feasibility of an approach based on pharmacologic stress echocardiography as a gatekeeper for extended heart donor criteria. METHODS: From April 2005 to April 2010, 39 "marginal" candidate donors (mean age, 56 ± 6 years; 21 men) were initially enrolled. After legal declaration of brain death, marginal donors underwent rest echocardiography, and if the results were normal, dipyridamole (0.84 mg/kg over 6 min, n = 25) or dobutamine (up to 40 µg/kg/min, n = 3) stress echocardiography. RESULTS: A total of 19 eligible hearts were found with normal findings. Of these, three were not transplanted because of the lack of a matching recipient, and verification by cardiac autopsy showed absence of significant coronary artery disease or cardiomyopathy abnormalities. The remaining 16 eligible hearts were uneventfully transplanted in marginal emergency recipients. All showed normal (n = 14) or nearly normal (minor single-vessel disease in two) angiographic, intravascular ultrasound, hemodynamic and ventriculographic findings at 1 month. At follow-up (median, 14 months; interquartile range, 4-31 months), 14 patients survived and two had died, one at 2 months from general sepsis and one at 32 months from allograft vasculopathy in recurrent multiple myeloma. CONCLUSIONS: Pharmacologic stress echocardiography can safely be performed in candidate heart donors with brain death and shows potential for extending donor criteria in heart transplantation.

Serial assessment of peak VO2 and VO2 kinetics early after heart transplantation.

PURPOSE: Serial evaluation of aerobic metabolism and exercise tolerance early after heart transplantation (HT). METHODS: Fifteen heart transplant recipients (HTR), aged 52.0 +/- 9.9 yr (mean +/- SD), not undergoing structured rehabilitation programs, were tested two to four times during the first 2 yr post-HT. As a reference, a group of 11 healthy untrained controls (C) was utilized. Peak heart rate (peak HR), peak O2 uptake (peak VO2), and ventilatory threshold (VT) were determined during incremental bicycle exercise to voluntary exhaustion. VO2 kinetics were evaluated during constant-load exercise below VT, with determination of the duration of the "cardiodynamic" component (TDp) and of the time constant of the "primary" component (taup). RESULTS: Peak VO2 (L.min-1) was positively related to months post-HT (y=1.17 + 0.02x, P=0.003), and it increased by approximately 30% during the investigated period, although values in HTR were lower than in C (2.19 +/- 0.24). Peak HR was lower in HTR (136 +/- 15 beats.min-1) than in C (168 +/- 5), and it was not related to time post-HT. TDp was longer in HTR (31.4 +/- 6.3 s) than in C (23.2 +/- 6.1), and it was not related to time post-HT. A subgroup of HTR with markedly longer taup during the first months post-HT showed a significant decrease of this parameter as a function of time post-HT. CONCLUSIONS: Aerobic metabolism is impaired in HTR. Both central (cardiovascular) and peripheral (skeletal muscle) factors contribute to the reduced exercise tolerance. HTR showed, during the first 2 yr post-HT, a significant increase in peak VO2 and (in the patients with the slowest VO2 kinetics during the first months after HT) a significant improvement of the VO2 kinetics. The main gains seem to occur at the peripheral level.