Background: In patients with heart failure with preserved ejection fraction (HFpEF), worse kidney function is associated with worse overall cardiac mechanics. The direct relationship between right ventricular function and kidney function is unclear. Right ventricular stroke work index (RVSWI) is a marker of right ventricular function. Increased RVSWI indicates higher right ventricular workload. The aim of our study was to determine the relationship between RVSWI and glomerular filtration rate (GFR) in patients with HFpEF.
Hypothesis: There is a relationship between RVSWI and GFR in patients with HFpEF
Method: This was a single center cross sectional study. HFpEF is defined as patients with documented HFpEF with ejection fraction >50% and pulmonary wedge pressure > 15 mmHg from right heart catheterization. Patients with significant valvular heart disease, end-stage renal disease, prosthetic valve and organ transplant were excluded. Right ventricular stroke work index (RVSWI, normal value 8-12 g/m/beat/m2) was calculated using the formula, RVSWI= 0.0136x Stroke volume index x (Mean pulmonary artery pressure-mean right atrial pressure). Glomerular filtration rate was calculated using MDRD formula. Univariate and multivariate linear regression analysis was done to study the correlation between RVSWI and GFR.
Result: Ninety-one patients were included in the study. The patients were predominantly female (n=64, 70%) and African American (n=61, 67%). Mean age was 66±12 years. Eighty-six (78%) patients had hypertension, 63(69%) had diabetes mellitus. Mean GFR was 59±35 ml/min/1.73m2. Mean RVSWI was 11±6 g/m/beat/m2. Linear regression analysis showed that there was a significant inverse relationship between RVSWI and GFR (unstandardized coefficient = -1.48, p= 0.01). After adjusting for confounders including age, sex, race, hypertension, diabetes mellitus, dyslipidemia and smoking status, the association remained significant (unstandardized coefficient = -1.3, p= 0.029).
Conclusion: High right ventricular workload indicated by high right ventricular stroke work index is associated with worse renal function in patients with HFpEF. Further prospective studies are needed to better understand this association.