PURPOSE: According to the new Dana Point classification, pulmonary hypertension (PH) in patients with Chronic Renal Failure (CRF) is now classified under group 5 which includes those forms of PH where the underlying mechanism is either unclear or multi-factorial. Incidence of PH is increased in patients with CRF, especially in patients with end-stage renal disease on hemodialysis via an arterio-venous fistula (AVF). Various mechanisms have been suggested for PH in these patients including the increase in cardiac output (CO) due to the AVF, anemia, hormonal changes and left ventricular dysfunction but the exact pathogenesis remains unclear. The purpose of this study is to evaluate possible mechanisms for PH in patients with CRF.
METHODS: We examined data on 159 patients with CRF (GFR < 60) who had undergone right heart catheterization (RHC) for evaluation of PH noted on echocardiography. 57 of the 159 patients were excluded due to valvular heart disease. We compared the clinical, laboratory and hemodynamic characteristics of the remaining 102 patients with and without PH on RHC. The hemodynamic data examined included pulmonary capillary wedge pressure (PCWP), CO, mixed venous pO2 and left ventricular end diastolic pressure (LVEDP).
RESULTS: Of the 102 patients noted to have PH on echocardiography, 57 patients (56%) had PH and 45 (44%) did not have PH on RHC. 45 of 57 (79%) patients with PH had a PCWP >15 mmHg and 46 (81%) patients had a LVEDP > 15mmHg. Among the patients with and without PH, there was no significant difference in their CO but in the patients with PH, there was a significant increase in their PCWP and LVEDP.
CONCLUSION: Among patients with PH on echocardiography, a significant number of patients had no PH on RHC. The increase in PCWP and LVEDP without any increase in CO in patients with PH and CRF suggests that the cause of the PH in these patients is fluid overload or diastolic dysfunction.
CLINICAL IMPLICATIONS: Fluid overload or diastolic dysfunction is a common cause of PH in CRF.
DISCLOSURE: Vishal Sekhri, No Financial Disclosure Information; No Product/Research Disclosure Information