Cardiorenal Effects of Long-Term Phosphodiesterase V Inhibition in Pre-Heart Failure

Area of Science:

• Cardiology
• Nephrology
• Pharmacology

Background:

• Phosphodiesterase V (PDEV) is elevated in heart failure, increasing cyclic guanosine monophosphate (cGMP) degradation and hindering natriuresis.
• PDEV inhibition has shown promise in animal models for enhancing renal response to B-type natriuretic peptide.
• Pre-heart failure is characterized by reduced ejection fraction and renal impairment.

Purpose of the Study:

• To investigate if long-term PDEV inhibition with tadalafil improves renal function and cardiorenal response in pre-heart failure patients after volume loading.
• To assess the impact of tadalafil on glomerular filtration rate (GFR) and urinary sodium/cGMP excretion.

Main Methods:

• A randomized trial involving 20 pre-heart failure patients with renal impairment, assigned to tadalafil or placebo (2:1 ratio).
• Baseline and post-saline load echocardiography and renal clearance studies were conducted.
• Patients received daily tadalafil (20 mg) or placebo for 12 weeks, with repeated assessments.

Main Results:

• Long-term tadalafil treatment did not significantly improve glomerular filtration rate (GFR) compared to placebo.
• No significant differences were observed in urinary sodium or cGMP excretion between the tadalafil and placebo groups after saline loading.
• The median GFR increase was 2.0 mL/min with tadalafil versus 13.5 mL/min with placebo (P=0.54).

Conclusions:

• Twelve weeks of tadalafil did not lead to significant improvements in GFR or urinary sodium/cGMP excretion in pre-heart failure patients.
• These findings do not support the use of PDEV inhibition to enhance renal response in individuals with pre-heart failure.
• Further research may be needed to explore alternative therapeutic strategies for cardiorenal dysfunction in this population.