Abstract
BackgroundThe 6th World Symposium on Pulmonary Hypertension (Nice 2018) proposed a new definition of pre-capillary pulmonary hypertension (PH) as a condition with mean pulmonary artery pressure (mPAP) > 20 mmHg, pulmonary artery wedge pressure ≤ 15 mmHg, and pulmonary vascular resistance (PVR) ≥ 3 Wood units (WU). The characteristics and prognosis of patients with pre-capillary PH, according to this new definition, is unclear. Therefore, we determined the characteristics and survival of patients with borderline pre-capillary PH.MethodsWe retrospectively enrolled 683 patients who underwent their first right heart catheterization at Chiba University, Japan. Among them, 489 patients met the pre-capillary PH requirement with mPAP ≥ 25 mmHg (conventional pre-capillary PH group), while 22 patients met the borderline pre-capillary PH criteria (borderline pre-capillary PH group). Additionally, 16 patients with a mean PAP of 20–25 and PVR of 2–3 WU were also examined.ResultsThe borderline pre-capillary PH group comprised 4.3% of the total patients with pre-capillary PH, and the majority was in Group 3 (40.9%) or 4 (45.5%). The survival of the borderline pre-capillary PH group tended to be better than that of the conventional pre-capillary PH group. The prognosis of Group3 PH was the worst among the patients with borderline precapillary PH. There was no significant difference in survival between the borderline pre-capillary PH group with PVR ≥ 3 WU and that with PVR of 2–3 2WU, although none of the patients in the latter group died due to right heart failure.ConclusionsThis is the first study conducted in a PH center in an Asian country to reveal the characteristics of patients with pre-capillary PH, according to the Nice 2018 definition. They comprised 4.3% of the total population with pre-capillary PH, and the majority of the pre-capillary PH cases were in either Group3 or 4. The prognosis may be affected by the patients’ underlying diseases. Further prospective studies are needed to determine whether the new definition, including the PVR cut-off, is beneficial in clinical practice.
Highlights
The 6th World Symposium on Pulmonary Hypertension (Nice 2018) proposed a new definition of pre-capillary pulmonary hypertension (PH) as a condition with mean pulmonary artery pressure > 20 mmHg, pulmonary artery wedge pressure ≤ 15 mmHg, and pulmonary vascular resistance (PVR) ≥ 3 Wood units (WU)
Recent data obtained for patients undergoing right heart catheterization (RHC) have shown that normal mean pulmonary artery pressure (mPAP) was 14.0 ± 3.3 mmHg in healthy subjects, and two standard deviations above this mean value would suggest that mPAP > 20 mmHg is above the upper normal limit [1, 2]
According to the clinical classification, most of the patients with borderline PH among the total patients in their specific Groups were in Group 3 (15%), and only 6.8% were in Group 4 (Table 1)
Summary
The 6th World Symposium on Pulmonary Hypertension (Nice 2018) proposed a new definition of pre-capillary pulmonary hypertension (PH) as a condition with mean pulmonary artery pressure (mPAP) > 20 mmHg, pulmonary artery wedge pressure ≤ 15 mmHg, and pulmonary vascular resistance (PVR) ≥ 3 Wood units (WU). The mPAP value is inadequate to define pulmonary vascular disease since this value can be affected by the cardiac output (CO) or pulmonary arterial wedge pressure (PAWP) Considering these aspects, the task force of the 6th WSPH in 2018 proposed that if all three criteria are met, namely, mPAP > 20 mmHg, PAWP ≤ 15 mmHg, and pulmonary vascular resistance (PVR) ≥ 3 Wood units (WU), the new definition of pre-capillary PH would be satisfied [1]. This study was conducted in a Japanese PH center that is associated with respiratory medicine and is one of the high-volume pulmonary endarterectomy (PEA) centers in Japan
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