Hemodynamics of the diastolic pressure gradients in acute heart failure: implications for the diagnosis of pre-capillary pulmonary hypertension in left heart disease.

The diastolic pressure gradient (DPG) has been proposed as the metric of choice for the diagnosis of pulmonary vascular changes in left heart disease. We tested the hypothesis that this metric is less sensitive to changes in left atrial pressure and stroke volume (SV) than the transpulmonary gradient (TPG). We studied the effect of dynamic changes in pulmonary capillary wedge pressure (PCWP), SV, and pulmonary artery capacitance (PAC) on DPG and TPG in 242 patients with acute heart failure undergoing decongestive therapy with continuous hemodynamic monitoring. There was a close impact of PCWP reduction on TPG and DPG, with a 0.13 mmHg (95% confidence interval [CI] 0.07-0.19, P < 0.0001) and 0.21 mmHg (95% CI 0.16-0.25, P < 0.0001) increase for every 1 mmHg decrease in PCWP, respectively. Changes in SV had a negligible effect on TPG and DPG (0.19 and 0.13 mmHg increase, respectively, for every 10-mL increase in SV). Heart rate was positively associated with DPG (0.41-mmHg increase per 10 BPM [95% CI 0.22-0.60, P < 0.0001]). The resistance-compliance product was positively associated with both TPG and DPG (2.65 mmHg [95% CI 2.47-2.83] and 1.94 mmHg [95% CI 1.80-2.08] for each 0.1-s increase, respectively). In conclusion, DPG is not less sensitive to changes in left atrial pressure and SV compared with TPG. Although DPG was not affected by changes in PAC, the concomitant increase in the resistance-compliance product increases DPG.