Aims: The diastolic pressure gradient (DPG) has been proposed as a marker pulmonary vascular disease in the setting of left heart failure (HF). However, its diagnostic utility is compromised by the high prevalence of physiologically incompatible negative values (DPGNEG) and the contradictory evidence on its prognostic value. Pressure pulsatility impacts on DPG measurements, thus conceivably, pulmonary artery wedge pressure (PAWP) measurements insusceptible to the oscillatory effect of the V-wave might yield a more reliable DPG assessment. We set out to investigate how the instantaneous PAWP at the trough of the Y-descent (PAWPY) influences the prevalence of DPGNEG and the prognostic value of the resultant DPGY.
Methods: Hundred and fifty-three consecutive HF patients referred for right heart catheterisation were enrolled prospectively. DPG, as currently recommended, was calculated. Subsequently, PAWPY was measured and the corresponding DPGY was calculated.
Results: DPGY yielded higher values (median, IQR: 3.2, 0.6-5.7 mmHg) than DPG (median, IQR: 0.9, - 1.7-3.8 mmHg); p < 0.001. Conventional DPG was negative in 45% of the patients whereas DPGY in only 15%. During follow-up (22 ± 14 months) 58 patients have undergone heart-transplantation or died. The predictive ability of DPGY ≥ 6 mmHg for the above defined end-point events was significant [HR 2.1; p = 0.007] and independent of resting mean pulmonary artery pressure (PAPM). In contrast, conventional DPG did not comprise significant prognostic value following adjustment for PAPM.
Conclusion: Instantaneous pressures at the trough of Y-descent yield significantly fewer DPGNEG than conventional DPG and entail superior prognostic value in HF patients with and without PH.
Keywords: Diastolic pressure gradient; Heart failure; Prognosis; Pulmonary wedge pressure; V-wave; Y-descent.