Page 50 - Assessing right ventricular function and the pulmonary circulation in pulmonary hypertension Onno Anthonius Spruijt

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Relationship between metrics of right heart function and hemodynamics
The different parameters of right heart size and function are not independent of each other; their inter-relationship is important to consider before outcome models are built. As expected, there was also strong collinearity between parameters of RV function (R2=0.61 between RVFAC and TAPSE [p<0.001] and R2=0.51 between RVFAC and RVMPI [p<0.001]), as well as between RVEDA and RA area (R2=0.51; p<0.001). Table 2 summarizes factors independently associated with RVFAC, RA area index, active and passive RAEF, and log NT-proBNP levels. We favored including in the model factors that were not only correlates but also potential determinants. As covariates, factors considered included demographic factors (age and sex), load parameters (PVRI and right atrial pressure [RAP]), functional indexes (tricuspid regurgitation and TAPSE), or renal function for NT-proBNP. Among other associations, we found that pericardial effusion, which was present in 17 patients, was strongly related to both RAP and RA size (chi-square=22; p=0.01). Systolic blood pressure (SBP) was significantly correlated with cardiac output, as well as the use of intravenous prostanoids (R2=0.28; p<0.011; r=0.40 with cardiac output and r=-0.28 with prostanoids).
R2 Correlates
RVFAC
0.32 PVRI (r=-0.44) Male (r=-0.30)
RAI
0.61 RAP (r=0.44) TR (r=0.45)
RAEFactive
0.41
RAP (r=-0.27) TAPSE (r=0.33) Male (r=-0.27)
RAEFpassive
0.27
Age (r=-0.35) TAPSE (r=0.47)
Log NT-proBNP
0.59 RVFAC (r=-0.48) RAI (r=0.40) eGFR (r=-0.31) Male (r=-0.24)
Table 2: The multivariate models presented are all p < 0.001. PVRI is based on the most recent right heart catheterization. r corresponds to partial correlation coefficients. NT-proBNP = N-terminal pro–B-type natriuretic peptide; RAEF = right atrial emptying fractions; RAI = right atrial area index; RVFAC = right ventricular fractional area change; TAPSE = tricuspid annular systolic excursion; TR = tricuspid regurgitation; other abbreviations as in Table 1.
Outcome analysis in the derivation cohort
The composite endpoint occurred in 34 patients (36%), including 26 deaths and 8 lung transplants. Event-free survival at 1, 3, and 5 years was 95%, 89%, and 81%, respectively. The predicted NIH survival equation 1-, 3-, and 5-year survival estimates were 66%, 44%, and 33%, respectively, and the revised NIH prediction scores were 91%, 71%, and 63% [17]. Several parameters of right heart structure and function were strongly related to outcome on univariate analysis (Table 3).