Aims A substantial shift in the field of pulmonary hypertension (PH) is ongoing, as
the previous practice of mean pulmonary arterial wedge pressure (PAWP(M)) is no longer
supported. Instead, aiming for a better estimate of end-diastolic pressures (EDP),
instantaneous PAWP at mid-A-wave (PAWP(mid-A)) or, in the absence of an A-wave, at
130-160 ms following QRS onset has recently been recommended. Electrocardiogram-gated
PAWP (PAWP(QRS)) has also been proposed. The quantitative differences as well as the
diagnostic and prognostic utility of these novel PAWP measurements have not been evaluated.
We set out to address these issues. Methods and results Pressure tracings of 141 patients
with PH due to left heart disease (PH-LHD) and 43 with primary pulmonary arterial
hypertension (PAH) were analysed. PAWP was measured as follows: (i) mean pressure
(PAWP(M)); (ii) per the latest consensus approach [PAWP(mid-A), or in atrial fibrillation
130, 140, 150, and 160 ms following QRS onset (PAWP(130-160))]; (iii) at QRS onset
(PAWP(QRS)); and (iv) Z-point (PAWP(Z)). For each PAWP, the corresponding pulmonary
vascular resistance (PVR) and diastolic pressure gradient were calculated. The cohort
comprised 45% female. Mean age was 66 +/- 15. PAWP(mid-A) was in good agreement with
PAWP(Z) (17.3 [14.5 to 21.2] vs. 17.6 [14.2 to 21.6] mmHg, P = 0.63), whereas PAWP(QRS)
provided significantly lower values (15.3 [12.5 to 19.2] mmHg, P < 0.001). In atrial
fibrillation, PAWP(130) and PAWP(QRS) yielded the optimal temporal and quantitative
analyses of EDPs. The ability to differentiate PAH from PH-LHD was similar for the
various PAWP measurements [PAWP(M): area under the curve (AUC) 0.98, confidence interval
(CI) 0.96-0.99; PAWP(mid-A/130): AUC 0.94, CI 0.91-0.98; PAWP(QRS): AUC 0.96, CI 0.94-0.99,
P < 0.001 for all]. PVR based on instantaneous PAWP measurements failed to provide
superior prognostic information in PH-LHD as compared with conventional PVR. Conclusions
Although instantaneous PAWP measurement might better represent EDP, they nevertheless
fail to yield incremental diagnostic or prognostic information in PH-LHD as compared
with conventional measurements.
