Impact of the revised hemodynamic definition on the diagnosis of precapillary pulmonary hypertension: a retrospective single-center study in China

Abstract

Background: In the 6^th World Symposium on Pulmonary Hypertension (PH), the hemodynamic definition of PH was reduced from a mean pulmonary artery pressure (mPAP) ≥25 to >20 mmHg. This study aimed to evaluate the impact of the revised hemodynamic definition on the diagnosis of precapillary PH.

Methods: We retrospectively enrolled patients who underwent right heart catheterization from January 2012 to December 2018. All included patients were reassessed according to the revised hemodynamic definition.

Results: A total of 1,251 patients were included for analysis, of whom 1,044 patients had precapillary PH and 182 patients had mPAP <25 mmHg. After applying the revised definition, 33 (18.1%) of 182 patients with mPAP <25 mmHg were reclassified as having PH. However, only 7 of these 33 patients had a pulmonary vascular resistance ≥3 wood units and could be considered to have precapillary PH, accounting for 0.7% of the existing precapillary PH population. More importantly, 12 patients with mPAP ≥25 mmHg were delisted from precapillary PH for pulmonary vascular resistance <3 wood units (5 patients from Group III, 4 patients from Group IV, 3 patients from Group V). Overall, there was a net 0.5% decrease [(12-7)/1044×100%] in the population with precapillary PH.

Conclusions: The revised hemodynamic definition had a minor impact on the diagnosis of precapillary PH. It should be noted that the revised definition would influence not only patients with mPAP =21-24 mmHg, but also patients with mPAP ≥25 mmHg.

Keywords: Pulmonary hypertension; diagnosis; hemodynamics; precapillary pulmonary hypertension.

Figure 1

The differences in hemodynamic definitions among the 2009 ESC/ERS guidelines, 2015 ESC/ERS guidelines and 6^th WSPH. CO, cardiac output; ERS, European Respiratory Society; ESC, European Society of Cardiology; mPAP, mean pulmonary arterial pressure; PAWP, pulmonary arterial wedge pressure; PVR, pulmonary vascular resistance; WSPH, World Symposium on Pulmonary Hypertension.

Figure 2

Flowchart of the included and excluded patients in our study. *, One IPAH and 4 CHD-PAH could no longer be subgrouped as Group I for PVR ≤3 wood units under the 2015 ESC/ERS guidelines. **, One PH associated with tumor obstruction and 4 PH associated with vasculitis were reclassified as Group IV. ***, All patients had congenital heart disease associated with pulmonary hypertension, but they could not be subgrouped as Group I for PVR ≤3 wood units under the 2015 ESC/ERS guidelines. CHD-PAH, pulmonary arterial hypertension associated with congenital heart disease; ERS, European Respiratory Society; ESC, European Society of Cardiology; IPAH, idiopathic pulmonary arterial hypertension; PAWP, pulmonary arterial wedge pressure; PH, pulmonary hypertension; PVR, pulmonary vascular resistance.

Figure 3

The 6^th WSPH was used to reclassify PH patients diagnosed by the 2015 ESC/ERS guidelines. *, Those patients could no longer be considered as having precapillary PH due to PVR<3 wood units under the 6^th WSPH criteria. ^#, The underlying etiology of the PH of the patients (mPAP 21–24 mmHg, PVR <3 wood units) is shown in Figure 4. ^$, All patients had chronic thromboembolic pulmonary hypertension. ERS, European Respiratory Society; ESC, European Society of Cardiology; mPAP, mean pulmonary arterial pressure; PH, pulmonary hypertension; PVR, pulmonary vascular resistance; WSPH, World Symposium on Pulmonary Hypertension.

Figure 4

The underlying etiology of precapillary PH in 1,102 patients, stratified by mPAP and PVR. *, Classification is based on the 6^th WSPH. **, One patient was diagnosed as IPAH by the 2009 ESC/ERS guidelines at first and then reclassified as having unclassifiable PH by the 2015 ESC/ERS guidelines due to PVR ≤3. Therefore, the underlying etiology of PH in this patient is considered unclear/multifactorial. The remaining 3 patients were from Group V as directly diagnosed by the 2015 ESC/ERS guidelines (see Figures 2,3). CHD, congenital heart disease; CTD, connective tissue diseases; CTE, chronic thromboembolism; CTEPH, chronic thromboembolic pulmonary hypertension; COPD, chronic obstructive pulmonary disease; ERS, European Respiratory Society; ESC, European Society of Cardiology; IPAH, idiopathic pulmonary arterial hypertension; mPAP, mean pulmonary arterial pressure; PAWP, pulmonary arterial wedge pressure; PH, pulmonary hypertension; PVR, pulmonary vascular resistance.