PULMONARY HYPERTENSION AND CHRONIC KIDNEY DISEASE: INVASIVE HEMODYNAMIC ETIOLOGY AND OUTCOMES IN A LARGE ELECTRONIC MEDICAL RECORD-BASED COHORT

Beyond the Lungs: Systemic Manifestations of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a disease characterized by progressive loss and remodeling of the pulmonary arteries, resulting in right heart failure and death. Until recently, PAH was seen as a disease restricted to the pulmonary circulation. However, there is growing evidence that patients with PAH also exhibit systemic vascular dysfunction, as evidenced by impaired brachial artery flow-mediated dilation, abnormal cerebral blood flow, skeletal myopathy, and intrinsic kidney disease. Although some of these anomalies are partially due to right ventricular insufficiency, recent data support a mechanistic link to the genetic and molecular events behind PAH pathogenesis. This review serves as an introduction to the major systemic findings in PAH and the evidence that supports a common mechanistic link with PAH pathophysiology. In addition, it discusses recent studies describing morphological changes in systemic vessels and the possible role of bronchopulmonary anastomoses in the development of plexogenic arteriopathy. On the basis of available evidence, we propose a paradigm in which metabolic abnormalities, genetic injury, and systemic vascular dysfunction contribute to systemic manifestations in PAH. This concept not only opens exciting research possibilities but also encourages clinicians to consider extrapulmonary manifestations in their management of patients with PAH.

Pulmonary hypertension in patients with chronic kidney disease: invasive hemodynamic etiology and outcomes

Pulmonary hypertension (PH) is common in patients with chronic kidney disease (CKD) and associated with increased mortality but the hemodynamic profiles, clinical risk factors, and outcomes have not been well characterized. Our objective was to define the hemodynamic profile and related risk factors for PH in CKD patients. We extracted clinical and hemodynamic data from Vanderbilt's de-identified electronic medical record on all patients undergoing right heart catheterization during 1998-2014. CKD (stages III-V) was defined by estimated glomerular filtration rate thresholds. PH was defined as mean pulmonary pressure ≥ 25 mmHg and categorized into pre-capillary and post-capillary according to consensus recommendations. In total, 4635 patients underwent catheterization: 1873 (40%) had CKD; 1518 (33%) stage 3, 230 (5%) stage 4, and 125 (3%) stage 5. PH was present in 1267 (68%) of these patients. Post-capillary (n = 965, 76%) was the predominant PH phenotype among CKD patients versus 302 (24%) for pre-capillary ( P < 0.001). CKD was independently associated with pulmonary hypertension (odds ratio = 1.4, 95% confidence interval = 1.18-1.65). Mortality among CKD patients rose with worsening stage and was significantly increased by PH status. PH is common and independently associated with mortality among CKD patients referred for right heart catheterization. Post-capillary was the most common etiology of PH. These data suggest that PH is an important prognostic co-morbidity among CKD patients and that CKD itself may have a role in the development of pulmonary vascular disease in some patients.

Kidney dysfunction in patients with pulmonary arterial hypertension

Pulmonary arterial hypertension (PH) and chronic kidney disease (CKD) both profoundly impact patient outcomes, whether as primary disease states or as co-morbid conditions. PH is a common co-morbidity in CKD and vice versa. A growing body of literature describes the epidemiology of PH secondary to chronic kidney disease and end-stage renal disease (ESRD) (WHO group 5 PH). But, there are only limited data on the epidemiology of kidney disease in group 1 PH (pulmonary arterial hypertension [PAH]). The purpose of this review is to summarize the current data on epidemiology and discuss potential disease mechanisms and management implications of kidney dysfunction in PAH. Kidney dysfunction, determined by serum creatinine or estimated glomerular filtration rate, is a frequent co-morbidity in PAH and impaired kidney function is a strong and independent predictor of mortality. Potential mechanisms of PAH affecting the kidneys are increased venous congestion, decreased cardiac output, and neurohormonal activation. On a molecular level, increased TGF-β signaling and increased levels of circulating cytokines could have the potential to worsen kidney function. Nephrotoxicity does not seem to be a common side effect of PAH-targeted therapy. Treatment implications for kidney disease in PAH include glycemic control, lifestyle modification, and potentially Renin-Angiotensin-Aldosterone System (RAAS) blockade.