The application of official policy. Prophylaxis recommendations for patients with mitral valve prolapse.

In 1977, the American Heart Association recommended that patients with mitral valve prolapse (MVP) and mitral insufficiency receive antibiotic prophylaxis prior to procedures that place them at risk for bacterial endocarditis. To study how clinicians conformed to this recommendation, the authors selected 126 patients with MVP admitted to a University Medical Center in 1978, the year following the official policy. Overall, only 47 patients (37%) had the antibiotic prophylaxis recommended. Furthermore, information that might have increased the certainty of diagnosis of MVP or the likelihood of mitral insufficiency did not influence the physician's decision: symptoms, previous history, procedures, sex, evidence for mitral insufficiency, other serious illnesses, or the use of cardiac medications. However, patients seen in consultation by a cardiologist were much more likely to have prophylaxis recommended (P less than 0.05). It was concluded that the application of an official policy about prophylaxis for a condition such as MVP, where the risks are uncertain, is likely to be guided by other factors, such as the opinions of local experts.