Pulmonary Hypertension, Right Ventricular Remodeling and Outcomes in CKD

Pulmonary hypertension (PH), defined as a mean pulmonary artery pressure >20 mm Hg, is a common comorbidity in patients with CKD. The prevalence of PH increases as kidney function declines, and PH is associated with a higher risk of cardiovascular complications and mortality. The pathophysiology of PH in CKD has not been studied in detail primarily because studies incorporating right heart catheterization, the gold-standard test for diagnosing and phenotyping PH, are rare, and therefore, data regarding the hemodynamic phenotypes of PH in patients with CKD are sparse. Factors such as left-sided heart failure, anemia, and the presence of arteriovenous fistulas all likely play a role in the development of PH in patients with CKD. As pressures in the pulmonary arteries increase, maladaptive changes, such as hypertrophy and dilation, occur in the right ventricle to maintain cardiac output, eventually leading to clinical heart failure and death. Although this pathologic cycle is well characterized in patients with pulmonary arterial hypertension, there are few data on longitudinal changes in the RV in patients with PH and CKD. There are no specific treatments that have been evaluated for PH in the CKD population although there are several strategies which may mitigate the effects of PH including improved volume management, reduction in flow of high-flow arteriovenous fistulas, and potentially kidney transplantation. The role of medications used for pulmonary arterial hypertension in patients with CKD is unclear because patients with advanced CKD were excluded from most clinical trials of these therapies. More research is needed including the characterization of longitudinal right ventricular changes in patients with CKD, refinement of the molecular pathways implicated in the pathogenesis of PH, fistula flow rates which put patients at risk for the development of PH, and clinical trials of PH therapies in patients with CKD.