Background The prognostic implications of combined pre- and post-capillary pulmonary hypertension (Cpc-PH) in patients with pulmonary hypertension due to left heart disease (PH-LHD) remain controversial. The aim of this retrospective study was to evaluate the new PH-LHD criteria, recommended by the 6th World Symposium on Pulmonary Hypertension and to determine the prognostic value of Cpc-PH. Methods A total of 701 patients with symptomatic heart failure who had undergone right-heart catheterization were divided into the following four groups: (i) Isolated post-capillary PH (Ipc-PH) group; mean pulmonary artery pressure (mPAP) 20 mmHg, pulmonary artery wedge pressure (PAWP) 15 mmHg, and pulmonary vascular resistance (PVR) 20 mmHg, PAWP 15 mmHg, and PVR [greater than or equal to]3 WU (iii) borderline-PH group; mPAP 20 mmHg and PAWP [less than or equal to]15 mmHg (iv) non-PH group; mPAP [less than or equal to]20 mmHg. Multivariate Cox hazard analysis was used to investigate whether Cpc-PH was associated with cardiac outcomes. Results The study subjects were allocated into the Ipc-PH (n = 268), Cpc-PH (n = 54), borderline-PH (n = 112), or non-PH (n = 267) groups. The Cpc-PH group was associated significantly with adverse cardiac events even after adjustment for clinically relevant confounding factors for heart failure prognosis (vs. non-PH group: HR 2.98 [95% CI 1.81-4.90], P Conclusions The new definitions of PH-LHD stratified patients into 4 categories. Long-term clinical outcomes were significantly different between the four categories, with Cpc-PH having the worst cardiac outcomes.