Effect of left ventricular assist device implantation on right ventricular function: Assessment based on right ventricular pressure-volume curves.

Right ventricular (RV) failure is significantly associated with morbidity and mortality after left ventricular assist device (LVAD) implantation. However, it remains unclear whether LVAD implantation could worsen RV function. Therefore, we aimed to investigate the effect of LVAD implantation on RV function by comparing RV energetics derived from the RV pressure-volume curve between before and after LVAD implantation. This exploratory observational study was performed between September 2016 and January 2018 at a national center in Japan. Twenty-two patients who underwent LVAD implantation were included in the analysis. We measured RV energetics parameters: RV stroke work index (RVSWI), which was calculated by integrating the area within the RV pressure-volume curve; RV minute work index (RVMWI), which was calculated as RVSWI × heart rate; and right ventriculo-arterial coupling, which was estimated as RV stroke volume/RV end-systolic volume. We compared RV energetics between before and after LVAD implantation. Although RVSWI was similar [424.4 mm Hg · mL/m2 (269.5-510.3) vs. 379.9 mm Hg · mL/m2 (313.1-608.8), P = 0.485], RVMWI was significantly higher after LVAD implantation [29 834.1 mm Hg · mL/m2 /min (18 272.2-36 357.1) vs. 38 544.8 mm Hg · mL/m2 /min (29 016.0-57 282.8), P = 0.001], corresponding to a significantly higher cardiac index [2.0 L/min/m2 (1.4-2.2) vs. 3.7 L/min/m2 (3.3-4.1), P < 0.001] to match LVAD flow. Right ventriculo-arterial coupling was significantly higher after LVAD implantation [0.360 (0.224-0.506) vs. 0.480 (0.343-0.669), P = 0.025], suggesting that the efficiency of RV performance improved. In conclusion, higher RVMWI with higher cardiac index to match LVAD flow and improved efficiency of RV performance indicate that LVAD implantation might not worsen RV function.

Comparison of Right Ventricular Function Between Patients With and Without Pulmonary Hypertension Owing to Left-Sided Heart Disease: Assessment Based on Right Ventricular Pressure-Volume Curves.

OBJECTIVES: Right ventricular (RV) failure with pulmonary hypertension (PH) is frequently encountered in patients with advanced left-sided heart disease (LHD). However, RV energetics in patients with postcapillary PH because of LHD has not been well studied. The authors investigated intraoperative RV energetics in patients with PH due to LHD based on pressure-volume curves with three-dimensional transesophageal echocardiography and pulmonary artery catheterization. DESIGN: Exploratory study. SETTING: National center. PARTICIPANTS: Thirty-three patients who underwent cardiac surgery for LHD were enrolled. Ten patients had PH (mean pulmonary artery pressure ≥ 25 mmHg). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: RV stroke work index (RVSWI) was calculated by integrating the area bounded by the pressure-volume curve. RV minute work index (RVMWI) was calculated as RVSWI × heart rate. Right ventriculo-arterial coupling was estimated as stroke volume divided by end-systolic volume (SV/ESV). The authors compared RV energetics between patients with and without PH because of LHD. RVSWI and RVMWI were significantly higher in patients with PH (690.7 mmHg·mL/m2 [601.6-737.1] v 440.9 mmHg·mL/m2 [330.8-585.3], p = 0.015, and 60,068 mmHg·mL/m2/min [35,547-68,741] v 26,351 mmHg·mL/m2/min [17,316-32,517], p = 0.011, respectively), although cardiac index was nearly identical. SV/ESV was significantly lower in patients with PH (0.520 [0.305-0.810] v 0.820 (0.650-1.090), p = 0.007). CONCLUSIONS: Although cardiac index was similar, RVSWI and RVMWI were significantly higher and SV/ESV was significantly lower in patients with PH because of LHD, suggesting that patients with postcapillary PH have inefficient RV performance.

Modern Invasive Hemodynamic Assessment of Pulmonary Hypertension.

Since 1998 pulmonary hypertension has been clinically classified into five well-defined, distinct categories. A definitive diagnosis of pulmonary hypertension requires the invasive confirmation of an elevated mean pulmonary artery pressure of 25 mm Hg or above during a right heart catheterization. From a hemodynamic point of view, pulmonary hypertension is classified into precapillary and postcapillary pulmonary hypertension on the basis of a pulmonary artery wedge pressure threshold value of 15 mm Hg. Pulmonary vascular resistance is better characterized by multi-point pressure/flow measurements than by single-point determination. Multi-point pulmonary vascular resistance calculation could be useful for early disease identification as well as for treatment response assessment. Occlusion analysis of the pulmonary artery pressure decay curve after balloon inflation at the tip of the pulmonary artery catheter permits locating the site of predominantly increased resistance and could be useful in differentiating proximal from distal vasculopathy, especially in chronic thromboembolic pulmonary hypertension. The pulsatile hydraulic load of the pulmonary circulation can be better appreciated by pulmonary vascular impedance or via the resistance-compliance relationship than by means of pulmonary vascular resistance. Determination of right ventriculo-arterial coupling permits assessing the impact of an elevated afterload on right ventricular function, which ultimately determines the symptoms and prognosis of patients with pulmonary hypertension. The clinical utility of combining different invasive hemodynamic approaches is still uncertain and remains to be determined.

Echocardiographic Assessment of Right Ventriculo-arterial Coupling: Clinical Correlates and Prognostic Impact in Heart Failure Patients Undergoing Cardiac Resynchronization Therapy.

BACKGROUND: Right ventriculo-arterial coupling (RV-PA) can be estimated by echocardiography using the ratio between tricuspid annular plane systolic excursion (TAPSE) and pulmonary artery systolic pressure (PASP) and it has prognostic value in the general heart failure (HF) population. We aimed to study the clinical correlates and prognostic value of RV-PA in HF patients undergoing cardiac resynchronization therapy (CRT). METHODS: We retrospectively studied 70 HF patients undergoing CRT implantation. RESULTS: RV-PA coupling was estimated by TAPSE/PASP ratio using baseline echocardiography. Non-response to CRT was defined as improvement of left ventricular ejection fraction < 5% in a follow-up echo 6-12 months after CRT. Those with lower TAPSE/PASP ratios (worse RV-PA coupling) had higher NT-proBNP concentrations and increased E/e' ratio. TAPSE/PASP ratio and PASP, but not TAPSE, predicted nonresponse to CRT with TAPSE/PASP ratio showing the best discriminative ability with a sensitivity of 76% and specificity of 71%. Among these parameters, PASP independently predicted all-cause mortality. CONCLUSIONS: RV-PA coupling estimated by TAPSE/PASP ratio was associated with established prognostic markers in HF. It numerically outperformed PASP and TAPSE in predicting the response to CRT. Our data suggest that this simple and widely available echocardiographic parameter conveys significant pathophysiological and prognostic meaning in HF patients undergoing CRT.

Right ventriculo-arterial coupling assessed by two-dimensional strain: A new parameter of right ventricular function independently associated with prognosis in chronic heart failure patients.

AIM OF THE STUDY: To evaluate whether right ventriculo-arterial coupling obtained by the estimation of the two-dimensional right ventricular (RV) longitudinal strain and of the pulmonary arterial systolic pressure (PASP) could improve prognostic stratification of chronic heart failure (CHF) outpatients. METHODS: CHF outpatients in a stable clinical condition and in conventional therapy were enrolled. The global RV longitudinal strain (RV-GLS) and the strain of the RV free wall (RV-fwLS) were evaluated. PASP was estimated on the basis of tricuspid regurgitation velocity and the estimated central venous pressure. Both RV-GLS and RV-fwLS were then indexed for PASP. RESULTS: Of the 315 patients evaluated, 69 died during follow-up. Both RV-GLS/PASP and RV-fwLS/PASP were significantly associated with an increased risk of death at univariate (HR: 0.43; 95%CI: 0.34-0.56; p<0.001 and HR: 0.44; 95% CI: 0.34-0.57; p<0.001, respectively) and multivariate analysis (HR: 0.66; 95% CI: 0.49-0.89; p: 0.008 and HR: 0.65; 95% CI: 0.49-0.85; p: 0.002, respectively) after correction for age, NYHA class, mean arterial pressure, left ventricular ejection fraction, natremia, glomerular filtration rate and NT-proBNP. CONCLUSIONS: Indexing RV function, assessed by speckle-tracking analysis, with an estimation of pulmonary systolic arterial pressure provides a parameter of ventricular arterial coupling that is independently associated with an increased risk of mortality.