The new diagnostic criteria for pre-capillary pulmonary hypertension may correspond more to the aims of the 6th World Symposium on Pulmonary Hypertension (WSPH) by recognizing patients with early forms of pulmonary vascular disease and poor prognosis, according to study results published in the journal CHEST.

Researchers retrospectively analyzed medical records from patients with pulmonary arterial wedge pressure ≤15 mm Hg who were undergoing right heart catheterization at a single site. Patient diagnoses and outcomes were compared between those who met the recently updated 6th WSPH definition of pre-capillary pulmonary hypertension and the previous definition. The aim of the study was to evaluate the effects of the new definition on the number and composition of patients with pre-capillary pulmonary hypertension.

Of the 630 patients undergoing right heart catheterization, the average age was 66 years (69% women). Patients were divided into 4 groups based on the previous and new definitions: (1) both definitions no pre-capillary pulmonary hypertension; (2) only the previous definition; (3) only the new definition; and (4) both definitions. A total of 281 patients were in group 1, 30 in group 2, 30 in group 3, and 289 patients in group 4. 

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Patients in group 1 had the lowest mean pulmonary arterial pressure (mPAP; 17 mm Hg) and pulmonary vascular resistance (PVR; 1.8 Wood units) values while those in group 4 had the highest (mPAP, 41 mm Hg and PVR, 7.7 Wood units). Since the number of patients in group 2 and 3 (only the previous definition and only the new definition, respectively) were the same, the absolute number of patients with pre-capillary pulmonary hypertension did not change. However, patients in group 3 tended to have shorter 6-minute walk distance scores compared with patients in group 2 (341 vs 387 meters, respectively) as well as lower diffusion capacity for carbon monoxide (59.2±16.4 vs 70.1±23.9 percent predicted, respectively; P =.07).

“[T]he new criteria for pre-capillary PH will be met by the same number of patients as the old criteria,” the study authors wrote.  “However, the hemodynamic and clinical profiles of ‘new pre-capillary PH’ patients correspond more to the aims of the 6th WSPH to recognize patients with early forms of pulmonary vascular disease and poor prognosis.”

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.


Kovacs G, Zeder K, Rosenstock P, et al. Clinical impact of the new definition of pre-capillary pulmonary hypertension. CHEST. Published online January 5, 2021. doi:10.1016/j.chest.2020.11.070