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Phosphodiesterase type 5 inhibition does not reverse endothelial dysfunction in patients with coronary heart disease
S D Robinson1, C A Ludlam, N A Boon
1Centre for Cardiovascular Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK. simon.robinson@ed.ac.uk
Insights
Sildenafil citrate does not improve blood vessel or blood clotting function in patients with coronary heart disease. This phosphodiesterase type 5 inhibitor is unlikely to reverse generalized vascular dysfunction in these patients.
Area of Science:
- Cardiovascular Medicine
- Pharmacology
Background:
- Coronary heart disease (CHD) is associated with endothelial dysfunction.
- Sildenafil citrate, a phosphodiesterase type 5 (PDE5) inhibitor, has shown vasodilatory effects.
Purpose of the Study:
- To investigate the effect of sildenafil citrate on endothelial vasomotor and fibrinolytic function in patients with CHD.
Main Methods:
- Randomized, double-blind, placebo-controlled, crossover study.
- 16 male patients with CHD and 8 healthy men received intravenous sildenafil or placebo.
- Forearm blood flow and tissue plasminogen activator release were measured in response to various infusions.
Main Results:
- Sildenafil reduced mean arterial blood pressure in both patients and controls.
- Sildenafil enhanced endothelium-independent vasodilation but did not affect endothelium-dependent responses.
- Sildenafil did not alter the release of tissue plasminogen activator.
Conclusions:
- Sildenafil does not improve peripheral endothelial vasomotor or fibrinolytic function in patients with CHD.
- PDE5 inhibitors are unlikely to reverse generalized vascular dysfunction in CHD.
Objectives:
To investigate whether sildenafil citrate, a selective phosphodiesterase type 5 inhibitor, may improve endothelial vasomotor and fibrinolytic function in patients with coronary heart disease.
Design:
Randomised double blind placebo controlled crossover study.
Patients And Methods:
16 male patients with coronary heart disease and eight matched healthy men received intravenous sildenafil or placebo. Bilateral forearm blood flow and fibrinolytic parameters were measured by venous occlusion plethysmography and blood sampling in response to intrabrachial infusions of acetylcholine, substance P, sodium nitroprusside, and verapamil.
Main Outcome Measures:
Forearm blood flow and acute release of tissue plasminogen activator.
Results:
Mean arterial blood pressure fell during sildenafil infusion from a mean (SEM) of 92 (1) to 82 (1) mm Hg in patients and from 94 (1) to 82 (1) mm Hg in controls (p < 0.001 for both). Sildenafil increased endothelium independent vasodilatation with sodium nitroprusside (p < 0.05) but did not alter the blood flow response to acetylcholine or verapamil in patients or controls. Substance P caused a dose dependent increase in plasma tissue plasminogen activator antigen concentrations (p < 0.01) that was unaffected by sildenafil in either group.
Conclusions:
Sildenafil does not improve peripheral endothelium dependent vasomotor or fibrinolytic function in patients with coronary heart disease. Phosphodiesterase type 5 inhibitors are unlikely to reverse the generalised vascular dysfunction seen in patients with coronary heart disease.
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