Clinical characteristics and survival analysis of class I pulmonary arterial hypertension.

Objective: To analyze the clinical data and prognosis of patients with World Health Organization (WHO) functional class I pulmonary arterial hypertension (PAH).

Methods: This research retrospectively analyzed the clinical data (baseline, laboratory as well as echocardiography and right heart catheterization data) of 63 class I PAH patients diagnosed and treated in the Department of Cardiology, First Affiliated Hospital of Zhengzhou University, between January 2021 and June 2022. The mean follow-up time was 10.7±6.5 months. The treatment and prognosis of the patients were analyzed.

Results: Among the class I PAH patients, the average age at diagnosis was 39.7±12.7 years, with females accounting for 92.1%; 44.4% of patients were at grade III or IV; 55.6% were at medium-high risk. In the subgroup analysis, there were more cases with grade III/IV cardiac function (P=0.03) and high risk in idiopathic PAH (IPAH) group than those in congenital heart disease-associated (CHD-PAH) and connective tissue disease-associated PAH (CTD-PAH) groups (P=0.04). CHD-PAH patients tended to present with higher pulmonary systolic blood pressure, mean pulmonary artery pressure and pulmonary vascular resistance than CTD-PAH patients (P<0.01), while IPAH patients had worse right ventricular end-systolic and end-diastolic volumes (P<0.05). The three subgroups showed no obvious differences in echocardiographic indexes (right atrial size, right ventricular size and pulmonary artery systolic pressure) and related laboratory indexes (blood routines and hepatorenal function). In terms of the targeted drug therapy for PAH, the proportion of dual-drug combination therapy was the highest (48.1%), followed by monotherapy (35%) and triple combination therapy (15.9%). Nearly half (48.7%) of CTD-PAH cases were first diagnosed in the Rheumatology and Immunology Department, and all of them were given targeted drug therapy for PAH. After a mean follow-up of 10.7±6.5 months, a total of 8 endpoint events occurred, including 3 deaths due to CTD-PAH complicated with serious complications of other organs. The 1-year survival rate for all the included PAH patients was 95.2%.

Conclusions: In the era of targeted therapy, class I PAH patients in China have a high early survival rate, a high proportion of combined therapy and strong multidisciplinary attention.