Microalbuminuria Predicts Elevated Right Ventricular Filling Pressure in Non-Obstructive Coronary Artery Disease.

Background: While microalbuminuria is established in left heart dysfunction prognostication, its relationship with right ventricular (RV) function remains unclear. We investigated whether microalbuminuria predicts early-stage RV dysfunction in patients with normal coronary arteries. Methods: This cross-sectional analysis involved 117 patients with angiography-verified non-obstructive CAD. Comprehensive RV echocardiography (including E/e' ratio) and morning urine albumin-creatinine ratio (UACR) measurements were performed. The study patients were categorized into 67 with normal albuminuria (mAlb (-): UACR <30 mg/g) and 50 with microalbuminuria (mAlb (+): UACR 30-300 mg/g). Multivariable logistic regression evaluated microalbuminuria's relationship with RV metrics, adjusting for sex, age, and BMI. A P<0.05 denoted statistical significance. Results: The mAlb (+) group demonstrated significantly higher RV E/e' ratios (P=0.026), persisting after adjustment. Logistic regression revealed that microalbuminuria independently predicted elevated RV filling pressure (OR 2.88, 95% confidence interval 1.22-6.84, P=0.016). Male sex showed non-significant trends (OR 1.69, P=0.286). RV systolic dysfunction prevalence was comparable between groups (16.4% overall, p=NS). Conclusion: Microalbuminuria independently associates with elevated RV filling pressures in non-obstructive CAD patients, suggesting shared microvascular pathophysiology. This supports albuminuria screening's potential role in identifying subclinical RV dysfunction, though longitudinal studies are needed to establish causality.