The diastolic pulmonary gradient does not predict survival in patients with pulmonary hypertension due to left heart disease

Abstract

Objectives: This study sought to evaluate if diastolic pulmonary gradient (DPG) can predict survival in patients with pulmonary hypertension due to left heart disease (PH-LHD).

Background: Patients with combined post- and pre-capillary PH-LHD have worse prognosis than those with passive pulmonary hypertension. The transpulmonary gradient (TPG) and pulmonary vascular resistance (PVR) have commonly been used to identify high-risk patients. However, these parameters have significant shortcomings and do not always correlate with pulmonary vasculature remodeling. Recently, it has been suggested that DPG may be better a marker, yet its prognostic ability in patients with cardiomyopathy has not been fully assessed.

Methods: A retrospective cohort of 1,236 patients evaluated for unexplained cardiomyopathy at Johns Hopkins Hospital was studied. All patients underwent right heart catheterization and were followed until death, cardiac transplantation, or the end of the study period (mean time 4.4 years). The relationships between DPG, TPG, or PVR and survival in subjects with PH-LHD (n = 469) were evaluated with Cox proportional hazards regression and Kaplan-Meier analyses.

Results: DPG was not significantly associated with mortality (hazard ratio [HR]: 1.02, p = 0.10) in PH-LHD whereas elevated TPG and PVR predicted death (HR: 1.02, p = 0.046; and HR: 1.11, p = 0.002, respectively). Similarly, DPG did not differentiate survivors from non-survivors at any selected cut points including a DPG of 7 mm Hg.

Conclusions: In this retrospective study of patients with cardiomyopathy and PH-LHD, an elevated DPG was not associated with worse survival.

Keywords: diastolic pulmonary gradient; left heart disease; pulmonary hypertension; survival.

Figure 1. Kaplan-Meir survival curves in all patients evaluated for heart failure

A. In patients with PH-LHD (mPAP ≥25mmHg and PCWP >15mmHg), higher DPG (≥7mmHg) failed to discriminate survivors. Patients without PH had better survival. B. In the subgroup of increased TPG, low DPG did not discriminate survivors. C. In subjects with PH-LHD and PVR ≥3WU, lower DPG showed a trend towards worse survival (P=0.051). * P <0.05, ** P <0.001; PH = Pulmonary Hypertension. DPG = Diastolic Pulmonary Gradient. TPG = Transpulmonary Gradient. PVR = Pulmonary Vascular Resistance. WU = Wood units.