Dobutamine stress echocardiography during follow-up surveillance in heart transplant patients: Diagnostic accuracy and predictors of outcomes

Background Cardiac allograft vasculopathy (CAV), a major cause of graft failure and mortality at >3 years after orthotopic heart transplantation (OHT), is commonly evaluated using dobutamine stress echocardiography (DSE). We sought to study: (a) the incidence of positive results and diagnostic accuracy of DSE; and (b) the predictors of adverse outcomes in OHT patients. Methods We studied 497 consecutive patients (63 ± 10 years, 78% men) with OHT who had undergone DSE as part of routine surveillance at our center between 1998 and 2013. Every DSE and coronary angiogram performed during follow-up was reviewed. CAV was regraded according to the 2010 recommendations of the International Society for Heart and Lung Transplantation. Composite events (death, coronary revascularization, myocardial infarction and retransplantation) were recorded. Results There were 1,243 DSE studies performed during a median of 8.7 (6.2 to 11.9) years after transplantation. Only 22 studies (1.8%) were positive, 978 (78.7%) were negative and 243 (19.5%) were non-diagnostic (sub-maximal heart rate response) for ischemia. Among 497 patients, only 20 (4%) had at least one positive DSE study. There were 310 diagnostic DSEs with coronary angiograms performed within 1 year of one another other. In this subgroup, the sensitivity, specificity, positive predictive value and negative predictive value of DSE were 7%, 98%, 82% and 41%, respectively, to detect any CAV, and 28%, 98%, 71% and 89% to detect CAV Grades 2 or 3, respectively. There were no deaths during DSE. At 5.6 ± 3.6 years after DSE, there were 201 (40%) events. Degree of CAV (and not DSE-based ischemia, p = 0.3) independently predicted outcomes ( p < 0.001). Conclusions The incidence of a positive result is very low in OHT patients undergoing surveillance DSE. DSE is insufficiently sensitive for detection of early CAV. Degree of CAV and not DSE-based ischemia independently predicted outcomes.