From the Journals

Combined PH subtypes predicts poor survival in kidney disease



A combined subtype of pulmonary hypertension was significantly associated with higher mortality in adults with chronic kidney disease, based on data from a retrospective study of 12,618 patients.

Pulmonary hypertension (PH) occurs in up to 41% of chronic kidney disease (CKD) patients, but most studies of PH in this population have not examined PH subtypes, wrote Daniel L. Edmonston, MD, of Duke University, Durham, N.C., and colleagues.

“Among patients with CKD with PH, the combined pre- and postcapillary PH subtype (elevated pulmonary capillary wedge pressure with increased pulmonary vascular resistance) may be a substantial contributor to the overall PH burden in CKD” because of factors including chronic volume overload, pulmonary vascular remodeling, inflammation, and comorbid lung disease, they wrote.

In a study published in the American Journal of Kidney Diseases, The researchers investigated subtypes of precapillary, postcapillary, and combination PH, and their associations with all-cause mortality for different levels of CKD severity. The study population included 12,618 adults aged 18 years and older with qualifying right-heart catheterizations. Of these, 4,772 had chronic kidney disease. The average age was 57 years in patients without CKD and 69 years in patients with CKD.

Overall, 73.4% of patients with CKD and 56.9% of patients without CKD had PH. For CKD patients, the most common PH subtypes were isolated postcapillary (39.0%) and combined pre- and postcapillary (38.3%).

Combined pre- and postcapillary PH was associated with higher mortality risk, compared with no PH in CKD patients, with adjusted hazard ratios of 1.89, 1.87, 2.13, and 1.63 for glomerular filtration rate categories G3a, G3b, G4, and G5/G5D, respectively.

For patients without CKD, precapillary PH was the most common subtype (35.9%) and was associated with the highest mortality risk, compared with no PH (HR, 2.27).

Relationships between mortality and specific PH features of mean pulmonary artery pressure, pulmonary capillary wedge pressure, and right atrial pressure were similar for patients with and without CKD.

The study findings were limited by several factors including the observational design, potential lack of generalizability because of the use of data from a single center, and lack of data on vascular access for hemodialysis, and exclusion of patients with heart or lung transplants, the researchers noted.

However, the results suggest that “processes that increase pulmonary vascular resistance and/ or remodeling represent a prominent mechanism and potential therapeutic target for patients with CKD that is complicated by PH,” they said.

Patients with CKD and combined pre- and postcapillary PH are at increased risk for mortality and “recognition of this large combined pre- and postcapillary PH cohort in CKD may present new therapeutic options,” they concluded.

The study was supported by the National Institutes of Health and the American Society of Nephrology. The researchers had no financial conflicts to disclose.

SOURCE: Edmonston DL et al. Am J Kidney Dis. 2019;75:713-24.


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