Current status of pulmonary arterial hypertension in Korea

Epidemiology of PAH in Korea: An Analysis of the National Health Insurance Data, 2002–2018

BACKGROUND AND OBJECTIVES

Pulmonary arterial hypertension (PAH) is a rare but fatal disease. Recent advances in PAH-specific drugs have improved its outcomes, although the healthcare burden of novel therapeutics may lead to a discrepancy in outcomes between developing and developed countries. We analyzed how the epidemiology and clinical features of PAH has changed through the rapidly advancing healthcare infrastructure in South Korea.

METHODS

PAH was defined according to a newly devised 3-component algorithm. Using a nationwide health insurance claims database, we delineated annual trends in the prevalence, incidence, medication prescription pattern, and 5-year survival of PAH in Korea. Cumulative survival and potential predictors of mortality were also assessed among 2,151 incident PAH cases.

RESULTS

Between 2002 or 2004 and 2018, the prevalence and incidence of PAH increased 75-fold (0.4 to 29.9 per million people) and 12-fold (0.5 to 6.3 per million person-years), respectively. The proportion of patients on combination PAH-specific drug therapy has also steadily increased up to 29.0% in 2018. Among 2,151 incident PAH cases (median [interquartile range] age, 50 [37-62] years; 67.2% female), the 5-year survival rate and median survival duration were 71.8% and 13.1 years, respectively. Independent predictors of mortality were age, sex, etiology of PAH, diabetes, dyslipidemia, and chronic kidney disease.

CONCLUSIONS

This nationwide study delineated that the prevalence and incidence of PAH have grown rapidly in Korea since the early 2000s. The use of combination therapy has also increased, and the 5-year survival rate of PAH in Korea was similar to those in western countries.

Pulmonary Hypertension Definition, Classification, and Epidemiology in Asia

Pulmonary hypertension (PH) is caused by a range of conditions and is important to recognize as it is associated with increased mortality. Pulmonary arterial hypertension refers to a group of PH subtypes affecting the distal pulmonary arteries for which effective treatment is available. The hemodynamic definition of pulmonary arterial hypertension has recently changed which may lead to greater case recognition and earlier treatment. The prevalence of specific PH etiologies may differ depending on geographic region. PH caused by left heart disease is the most common cause of PH worldwide. In Asia, there is greater proportion of congenital heart disease- and connective tissue disease- (especially systemic lupus erythematosus) related PH relative to the West. This review summarizes the definition, classification, and epidemiology of PH as it pertains to Asia.

Prevalence, incidence, and survival of pulmonary arterial hypertension: A systematic review for the global burden of disease 2020 study

Pulmonary arterial hypertension (PAH) is characterized by increased resistance in the pulmonary arterioles as a result of remodeled blood vessels. We sought all available epidemiologic data on population‐based prevalence, incidence, and 1‐year survival of PAH as part of the Global Burden of Disease Study. We performed a systematic review searching Global Index Medicus (GIM) for keywords related to PAH between 1980 and 2021 and identified population‐representative sources of prevalence, incidence, and mortality for clinically diagnosed PAH. Of 6772 articles identified we found 65 with population‐level data: 17 for prevalence, 17 for incidence, and 58 reporting case fatality. Reported prevalence ranged from 0.37 cases/100,000 persons in a referral center of French children to 15 cases/100,000 persons in an Australian study. Reported incidence ranged from 0.008 cases/100,000 person‐years in Finland, to 1.4 cases/100,000 person‐years in a retrospective chart review at a clinic in Utah, United States. Reported 1‐year survival ranged from 67% to 99%. All studies with sex‐specific estimates of prevalence or incidence reported higher levels in females than males. Studies varied in their size, study design, diagnostic criteria, and sampling procedures. Reported PAH prevalence, incidence, and mortality varied by location and study. Prevalence ranged from 0.4 to 1.4 per 100,000 persons. Harmonization of methods for PAH registries would improve efforts at disease surveillance. Results of this search contribute to ongoing efforts to quantify the global burden of PAH.

Dapagliflozin has No Protective Effect on Experimental Pulmonary Arterial Hypertension and Pulmonary Trunk Banding Rat Models

Sodium-glucose cotransporter-2 (SGLT2) inhibitors, a novel class of hypoglycemic drugs, show excellent cardiovascular benefits, and have further improved heart failure outcomes, significantly reducing cardiovascular and all-cause mortality irrespective of diabetes status. However, the efficacy of SGLT2 inhibitors in pulmonary arterial hypertension (PAH) and right ventricular (RV) dysfunction remains unknown. This study aimed to evaluate the effects of dapagliflozin in rats with PAH and RV dysfunction. PAH was induced in rats by monocrotaline (MCT) subcutaneous injection (60 mg/kg). Isolated RV dysfunction was induced in another group of rats by pulmonary trunk banding (PTB). Dapagliflozin (1.5 mg/kg) was administered daily via oral gavage one day (prevention groups) or two weeks (reversal groups) after modeling. Echocardiography and hemodynamic assessments were used to observe pulmonary vascular resistance and RV function. Histological staining was used to observe pulmonary vascular and RV remodeling. As compared with MCT group, dapagliflozin treatment did not significantly improve the survival of rats. Pulmonary arterial media wall thickness in MCT group was significantly increased, but dapagliflozin did not significantly improved vascular remodeling both in the prevention group and reversal group. In MCT group, RV hypertrophy index, RV area, the fibrosis of RV increased significantly, and RV function decreased significantly. Consistently, dapagliflozin did not show protective effect on the RV remodeling and function. In the PTB model, we also did not find the direct effect of dapagliflozin on the RV. This is a negative therapeutic experiment, suggesting human trials with dapagliflozin for PAH or RV failure should be cautious.

Comparative analysis on the anti-inflammatory/immune effect of mesenchymal stem cell therapy for the treatment of pulmonary arterial hypertension

Despite the advancement of targeted therapy for pulmonary arterial hypertension (PAH), poor prognosis remains a reality. Mesenchymal stem cells (MSCs) are one of the most clinically feasible alternative treatment options. We compared the treatment effects of adipose tissue (AD)-, bone marrow (BD)-, and umbilical cord blood (UCB)-derived MSCs in the rat monocrotaline-induced pulmonary hypertension (PH) model. The greatest improvement in the right ventricular function was observed in the UCB-MSCs treated group. The UCB-MSCs treated group also exhibited the greatest improvement in terms of the largest decrease in the medial wall thickness, perivascular fibrosis, and vascular cell proliferation, as well as the lowest levels of recruitment of innate and adaptive immune cells and associated inflammatory cytokines. Gene expression profiling of lung tissue confirmed that the UCB-MSCs treated group had the most notably attenuated immune and inflammatory profiles. Network analysis further revealed that the UCB-MSCs group had the greatest therapeutic effect in terms of the normalization of all three classical PAH pathways. The intravenous injection of the UCB-MSCs, compared with those of other MSCs, showed superior therapeutic effects in the PH model for the (1) right ventricular function, (2) vascular remodeling, (3) immune/inflammatory profiles, and (4) classical PAH pathways.

Prevalence and clinical features of bone morphogenetic protein receptor type 2 mutation in Korean idiopathic pulmonary arterial hypertension patients: The PILGRIM explorative cohort

Background

Pulmonary arterial hypertension (PAH) is a progressive chronic disease with poor outcomes. One reason for poor prognosis is the lack of understanding regarding individual variability in response to treatment. Idiopathic PAH (IPAH) patients with bone morphogenetic protein receptor type 2 (BMPR2) mutations have distinct phenotypes that are crucial for individualized therapy but evidence regarding their prevalence and clinical features in the Korean population is lacking. Therefore, the present study aimed to screen Korean IPAH patients for BMPR2 mutations and analyze their clinical phenotypes.

Methods

We enrolled 73 unrelated IPAH patients for BMPR2 mutation screening between March 2010 to November 2015 from 11 hospitals in Korea. Thirty-three lineal family members from 6 families of BMPR2 mutation carriers were also screened.

Results

Among 73 patients, 16 (22%) had BMPR2 mutations. Mutation carriers were younger (27 vs. 47 years; p = 0.02) and had a higher mean pulmonary arterial pressure (mPAP) than non-carriers (64 vs. 51 mmHg; p<0.05). Of the 16 individuals with mutations, 5 deletion, 2 splice-site, 6 nonsense, and 3 missense mutations were found, among which, 9 were newly identified mutation types. Patients less than 30 years old had more BMPR2 mutations (44 vs. 14%; p = 0.04) and a higher mPAP (64 vs. 50 mmHg; p = 0.04) compared with those equaled to or over 30 years old. There were no differences in hemodynamic profiles or the proportion of BMPR2 mutation carriers between groups according to sex.

Conclusion

The prevalence of BMPR2 mutations in Korean IPAH patients was 22%. Mutation carriers were younger and had a poorer hemodynamic profile compared with the non-carriers.

Clinical trial registration

Clinicaltrials.gov NCT01054105

Echocardiographic Screening Methods for Pulmonary Hypertension: A Practical Review

Pulmonary hypertension (PH) is a debilitating condition defined as mean pulmonary arterial pressure (mPAP) ≥ 25 mmHg. The importance of impaired right ventricular (RV) hemodynamics is increasingly being recognized in treatment of patients with PH. In World Health Organization Group 1 patients with pulmonary arterial hypertension, upfront combination therapy has recently been proposed to improve long-term survival. Also, the mPAP in Group 2 and 3 PH patients has been shown to be strongly associated with clinical outcomes. Thus, screening and monitoring of RV hemodynamics are becoming increasingly important. The gold standard for measuring RV hemodynamics is right heart catheterization (RHC). Although RHC can obtain the most accurate results, it is invasive, cumbersome to patients, and often associated with complications, making it unsuitable for a screening or monitoring modality. Echocardiography is useful in estimating hemodynamic parameters that can be obtained from RHC. Accordingly, the role of echocardiography in evaluating such patients with PH is becoming more important. In this article, we review practical echocardiographic methods in approximating RV hemodynamics for PH.