RESULTS
STUDY POPULATION . Of 212 enrolled in the study, 45 patients
with atrial fibrillation and 46 with pacemaker therapy were first
excluded. Nine patients were subsequently excluded after RHC revealed
isolated pre-capillary alterations. Ultimately, 112 patients (60 ± 16
years; 46% Female) were included in the analysis. Baseline
characteristics are presented in Table 1. All subjects demonstrated
signs and symptoms of HF, elevated NTproBNP and objective evidence of LV
systolic and/or diastolic function. Echocardiographic and invasive data
of the cohort is presented in Table 2. LV EF was reduced (<
50%) in 55 (49%) of the patients. Patients had elevated filling
pressures represented by elevated mitral E/e’, dilated LA volumes and
elevated PA systolic pressure. Further, the cohort demonstrated elevated
PA systolic, diastolic, mean pressures (PAPS,
PAPD and PAPM respectively), mean
pulmonary capillary wedge pressures (PAWPM) and
increased pulmonary vascular resistance (PVR) on RHC. Sixty-five
patients (58%) demonstrated PH, as defined by PAPM ≥
25mmHg.
FEASIBILITY AND ACCURACY OF DOPPLER PAPMALGORITHMS. Echocardiographic assessment of PAPM was
most feasible employing the approach considering RVOTATintroduced by Dabestani et al12 (86% of patients
could have PAPm assessed using this method), followed by TR-derived
assessments by Chemla et al8 (84%) and Aduen et
al5 (81%). PAPM estimated using the
PR-derived approach (Abbas et al7) was least feasible
of the 4 methods (53%). All echocardiographic PAPMalgorithms demonstrated a moderately significant correlation with
invasive variables (r = 0.41 to 0.65; p < 0.001 for all)
(Figure 2). The method proposed by Aduen et al5demonstrated the strongest relationship (r = 0.65; p < 0.001),
comparable with how recommendation-based TRVmax (r =
0.64; p < 0.001) correlated with PAPM.
Agreement between each echocardiographic approach and RHC was studied
using Bland-Altman analysis (Figure 3). Echocardiography demonstrated
good accuracy to represent invasive pressures in the methods employing
TR gradients (Aduen et al5 and Chemla et
al8), as seen in relatively low bias between
echocardiography and RHC (bias = +2.4 and -2.4mmHg respectively).
Moderate precision was observed with limits of agreement (mean value +
1.96 x SD) in the range of ±20mmHg for both methods. Relatively higher
systematic error between diagnostic modalities was observed for
approaches by Dabestani et al12 (that employed
RVOTAT) that overestimated invasive measurements (bias =
+4.2mmHg) and Abbas et al7 (that employed PR peak
velocity) that underestimated invasive measurements (bias = -6.1mmHg).
Relatively wider limits of agreement were seen in both algorithms
(Figure 3).
DIAGNOSTIC PERFORMANCE OF ECHOCARDIOGRAPHIC ALGORITHMS TO ASSIGN
PH PROBABILITY. Recommendation-based TRVmaxdemonstrated strong discriminatory ability to identify invasive
PAPM ≥ 25mmHg (AUC = 0.84, CI 0.76 to 0.91; p
< 0.001). All echocardiographic approaches demonstrated
moderate to strong discrimination (AUC range 0.70 to 0.80; p <
0.001 for all) with the Chemla et al algorithm8demonstrating strongest diagnostic performance (AUC = 0.80, CI 0.71 to
0.89; p < 0.001) (Figure 4). Sensitivity, Specificity, PPV and
NPV of TRVmax and algorithms to identify invasive
PAPM ≥ 25mmHg are presented in Table 3. The recommended
TRVmax cut-off of 2.8m/sec demonstrated 83% sensitivity
and 61% specificity to identify PAPM ≥ 25mmHg. At a
cut-off of 25mmHg, PAPM derived by Aduen et
al5 and Dabestani et al12demonstrated low specificity (38% and 35% respectively) and Abbas et
al,7 low sensitivity (48%). The only algorithm to
show comparable, strong, balanced sensitivity and specificity was that
proposed by Chemla et al8 (78% sensitivity and 67%
specificity).
ACCURACY OF ECHOCARDIOGRAPHIC RIGHT ATRIAL PRESSURE ESTIMATES.Echocardiographic RAP employing IVC size and collapse were incorporated
to calculate PAPM in all DE algorithms with the
exception of the approach postulated by Dabestani et
al.10 In 107 subjects (96%) with interpretable
images, RAP estimated by IVC was elevated (8 or 15mmHg) in 78% subjects
(n = 83, RAP = 8mmHg in 43 and 15mmHg in 40 subjects). However false
positives were frequent, as seen in 12 of 40 patients (30%) with
significantly elevated RAP estimated by echocardiography (15mmHg) that
had normal invasive RAP (≤7mmHg).