Dobutamine Stress Echocardiography for Orthotopic Liver Transplant Evaluation

We read the article by Williams et al., entitled “Dobutamine stress echocardiography in patients undergoing liver transplant evaluation” with great interest (1). Upon careful consideration of the Materials and Methods section, as well as the Conclusions section, the following points must be made. The most notable problem is that patients at highest risk for coronary artery disease were excluded from this study. Patients with stable angina and symptoms of myocardial ischemia were sent directly to cardiac catheterization (cath). We cannot necessarily argue with this approach; however, it would be interesting to know the cath results. One of the virtues of dobutamine stress echocardiography (DSE) is to avoid the unnecessary invasiveness and cost of cath. In addition, for those that were referred for DSE, it was not clear what criteria were used when deciding whom to screen. In their series, 50% of patients did not reach target heart rate. In our published and ongoing experience, this occurs in only about 5–10%. Furthermore there is no literature to support this incredibly high rate. We do, however, support their idea of stopping β-blockers 24 hr before DSE to minimize nondiagnostic results. It would be interesting to know what, if any, further work-up occurred in their two patients with abnormal DSE results. Although they made it through liver transplantation without cardiac sequela, that does not necessarily mean that coronary artery disease was absent. Finally, none of the “significant perioperative events“ that occurred in their series related to myocardial ischemia/coronary artery disease. DSE cannot be expected to detect perioperative hemorrhage, electrolyte imbalances or other nonischemic, nonanatomic cardiac related issues. It is therefore unfair to imply that DSE was not predictive of perioperative cardiac events. In addition, the authors failed to give any data about the detection of valvular disorders, intrapulmonary shunting, cardiomyopathy, and/or portopulmonary hypertension, all of which may be detected using DSE in addition to ischemic cardiac disease. In conclusion, we stand by our published results (2) and recommend DSE as the screening study of choice to rule out coronary artery disease in patients undergoing evaluation for OLT. We would also take this opportunity to reiterate the notion that screening studies must be applied to the proper population to be cost effective, and therefore, would recommend following the guidelines we have previously published (2). Jeffrey S. Plotkin1 Lynt B. Johnson Vinod K. Rustgi Paul C. Kuo, and Amy D. Liu