Dobutamine stress echocardiography after cardiac transplantation: implications of donor-recipient age difference

Dobutamine stress echocardiography (DSE) is widely used during follow-up after cardiac transplant for the diagnosis of allograft vasculopathy. We investigated the effect of donor-recipient age difference on the ability to reach target heart rate (HR) during DSE. All cardiac transplant patients who were undergoing DSE over a 3-year period in a single institution were reviewed. Target HR was specified as 85%×(220 - patient age). Further patient and donor demographics were obtained from the local transplant database. 61 patients (45 male, 55±12 years) were stressed with a median dose of 40 mcg/kg per min dobutamine. Only 37 patients (61%) achieved target HR. Donor hearts were mostly younger (mean 41±14 years, P<0.001), with only 11 patients (18%) having donors who were older than they were. Patients with older donors required higher doses of dobutamine (median 50 vs 30 mcg/kg per min, P<0.001) but achieved a lower percentage target HR (mean 93% vs 101%, P=0.003) than those with younger donors did. Patients with older donors were less likely to achieve target HR (18% vs 67%, P=0.003). In conclusion, donor-recipient age difference affects the likelihood of achieving target HR and should be considered when a patient is consistently unable to achieve 'adequate' stress according to the patient's age.