Proximal esophageal contraction after induction of ineffective distal contraction by sildenafil in healthy volunteers

BACKGROUND: Proximal esophagus is composed of striated muscle replaced by smooth muscle in the distal section. Sildenafil, an inhibitor of phosphodiesterase type 5, causes a decrease in the amplitude of contractions in distal smooth muscle esophagus, with no effect on the proximal esophageal striated muscle. The aim of this investigation was to evaluate the hypothesis that proximal contractions are affected by changes in distal contractions caused by sildenafil. METHODS: Esophageal motility was assessed by high resolution manometry in 22 healthy volunteers (12 women) aged 22-50 years (mean 38.1±7.7 years). All volunteers performed, in the sitting position, 10 swallows of liquid (5 mL of saline) and 10 swallows of solid boluses (1 cm(3) pieces of bread), before and after ingestion of 50 mg of sildenafil. We evaluated the proximal esophageal contractions in response to the changes in distal esophageal motility induced by sildenafil. RESULTS: Sildenafil caused a significant reduction in distal contractile integral and integrated relaxation pressure in the lower esophageal sphincter. In the proximal esophagus the alteration in distal esophageal contraction caused a significant increase in contraction length, contractile integral, and contraction duration. CONCLUSION: Induction of ineffective distal esophageal motility by sildenafil in healthy volunteers causes an increase in proximal esophageal motility, suggesting that proximal esophagus adapts to an induced impairment of distal esophageal motility.