Echocardiography in patients with suspected endocarditis: A cost-effectiveness analysis

PURPOSE: We sought to determine the appropriate use of echocardiography for patients with suspected endocarditis. PATIENTS AND METHODS: We constructed a decision tree and Markov model using published data to simulate the outcomes and costs of care for patients wit h suspected endocarditis. RESULTS: Transesophageal imaging was optimal for patients who had a prior p robability of endocarditis that is observed commonly in clinical practice ( 4% to 60%). In our base-case analysis (a 45-year-old man with a prior proba bility of endocarditis of 20%), use of transesophageal imaging improved qua lity-adjusted life expectancy (QALYs) by 9 days and reduced costs by $18 pe r person compared with the use of transthoracic echocardiography. Sequentia l test strategies that reserved the use of transesophageal echocardiography For patients who had an inadequate transthoracic study provided similar QA LYs compared with the use of transesophageal echocardiography alone, but co st $230 to $250 more. For patients with prior probabilities of endocarditis greater than 60%, the optimal strategy is to treat for endocarditis withou t reliance on echocardiography for diagnosis. Patients with a prior probabi lity of less than 2% should receive treatment for bacteremia without imagin g. Transthoracic imaging was optimal for only a narrow range of prior proba bilities (2% or 3%) of endocarditis. CONCLUSION: The appropriate use of echocardiography depends on the prior pr obability of endocarditis. For patients whose prior probability of endocard itis is 4% to 60"/o, initial use of transesophageal echocardiography provid es the greatest quality-adjusted survival at a cost that is within the rang e for commonly accepted health interventions. (C)1999 by Excerpta Medica, I nc.