Risk Score to Predict Right Heart Failure in LVAD Recipients

Study Questions:

Is the novel risk score for early right-sided heart failure (RHF) after left ventricular assist device (LVAD) implantation valid?

Methods:

The study authors used the European Registry for Patients With Mechanical Circulatory Support (EUROMACS) to identify adult patients undergoing continuous-flow LVAD implantation with mainstream devices. They randomly divided eligible patients (n = 2,988, age >18 years) into derivation (n = 2,000) and validation (n = 988) cohorts. The primary outcome was early (<30 days) severe postoperative RHF. They defined RHF as receiving short- or long-term right-sided circulatory support, continuous inotropic support for ≥14 days, or nitric oxide ventilation for ≥48 hours. The secondary outcome was all-cause mortality and length of stay in the intensive care unit. They entered covariates found to be associated with RHF (exploratory univariate p < 0.10) into a multivariable logistic regression model. They then generated a risk score using the relative magnitude of the exponential regression model coefficients of independent predictors at the last step after checking for collinearity, likelihood ratio test, c index, and clinical weight at each step.

Results:

The mean age of the cohort was 53 ± 13 years, and 18% (n = 523) were women. The majority were white (68%, n = 2,022). The main type of HF was nonischemic (66%, n = 1,985). The main indication for LVAD was bridge to candidacy (37%, n = 1,102), followed by bridge to transplantation (24.5%, n = 731). HeartWare HVAD was the most used LVAD brand (50.5%, n = 1,509), followed by HeartMate II (40.3%, n = 1,204), and the minority received Heart-Mate 3 (8%, n = 240). Early severe RHF occurs in one fifth of patients with LVAD in this study and 88% of patients have mild or more impairment of right ventricular (RV) systolic function. The study authors examined 82 potential preoperative predictors from which they created a 9.5-point risk score incorporating five variables (Interagency Registry for Mechanically Assisted Circulatory Support class, use of multiple inotropes, severe RV dysfunction on echocardiography, ratio of right atrial [RA]/pulmonary capillary wedge pressure [PCWP], hemoglobin). Patients in INTERMACS class 1-3 had a 27% risk of RHF versus 12% risk for those in INTERMACS class 4-7 (p < 0.001). Additionally, patients on ≥3 inotropic agents in the preoperative period had 42% risk of RHF versus 22% risk for those on ≤2 inotropic agents (p < 0.001). In terms of semi-quantitative echocardiographic assessment, patients with severe RV dysfunction on visual score had 50% risk of RHF versus 23% for those with better RV function. Furthermore, patients with an RA/PCWP ratio >0.54 had 27.1% risk of RHF versus 16.1% for those with a lower ratio (p < 0.001). Finally, patients with hemoglobin ≤10 g/dl had 35% risk of RHF versus 23% risk for those with hemoglobin >10 g/dl (p < 0.001). The mean scores in the derivation and validation cohorts were 2.7± 1.9 and 2.6 ± 2.0, respectively (p = 0.32). RHF in the derivation cohort occurred in 433 patients (21.7%) after LVAD implantation and was associated with a lower 1-year (53% vs. 71%; p < 0.001) and 2-year (45% vs. 58%; p < 0.001) survival compared with patients without RHF. RHF risk ranged from 11% (low risk score 0–2) to 43.1% (high risk score >4; p < 0.0001). Median intensive care unit stay was 7 days (interquartile range, 4–15 days) versus 24 days (interquartile range, 14–38 days) in patients without versus with RHF, respectively (p < 0.001). The use of multiple inotropes has the greatest weight in predicting post-LVAD RHF among all five predictors. The EUROMACS-RHF risk score outperformed (p < 0.0001) previously published scores and known individual echocardiographic and hemodynamic markers of RHF.

Conclusions:

The study authors concluded that this novel EUROMACS-RHF risk score outperformed currently known risk scores and clinical predictors of early postoperative RHF.

Perspective:

This is an important study because this simple and elegant risk score better predicts RHF in continuous-flow LVADs. Validation of this risk score in prospective studies is the next step, and if these findings are confirmed, this risk score should better predict RHF in continuous-flow LVAD patients.


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