Multicenter prospective investigation on cardiovascular adverse effects of tacrolimus in kidney transplantations

To clarify the incidence and pathophysiological mechanism of cardiovascular adverse effects of tacrolimus, the present prospective study performed scheduled cardiovascular examinations at 1, 2, 4, 8, 16, 20, and 24 weeks after starting the tacrolimus therapy in 68 consecutive kidney transplantation recipients enrolled from 26 institutes in Japan. Patients with previous coronary artery disease or congestive heart failure were excluded. The examinations included any subjective symptoms, changes in resting ECG, ambulatory Holter's dynamic ECG, two-dimensional echocardiography, and monitoring of serum drug concentrations and cardiac troponin T levels. Cardiac nuclear imaging and/or coronary angiography were performed in the case of suspicious coronary events. During the investigation, chest pain in 9 (13.2%) and palpitation in 6 patients (8.8%) were reported, both closely related to elevated blood drug concentrations (37.2 +/- 18.7 ng/mL, mean +/- SD). Cardiovascular examinations detected development of resting ECG abnormalities in 12 patients (17.6%), asymptomatic ST depression following increased heart rate in 11 (16.2%) and ventricular arrhythmias in 7 patients (10.3%) on Holter's dynamic ECG. Elevation of troponin T was detected in 3 patients (4.4%), which was also closely related to elevated drug concentrations and interpreted as myocardial damage associated with the therapy. Assessments by thallium(Tl)-201 myocardial scintigraphy and/or coronary angiography in patients with suspicious coronary events revealed only two patients (2.9%) were considered to be myocardial ischemia associated with coronary vasospasm or microcirculatory disturbance. Sequential evaluations on echocardiography revealed significant (p < 0.05) decrease in LV end-diastolic dimension (4, 8, 18 and 24 weeks) and LV end-systolic dimension (from 1 to 24 weeks), and significant (p < 0.05) increase in LV ejection fraction 1 to 4 weeks after the kidney transplantation. Thickening of LV wall (>2 mm compared with baseline) was detected in only one patient. The present prospective study detected totally 30.9% incidence of cardiovascular adverse events. Symptomatic events and troponin T elevation were closely related to elevated blood drug concentrations (>20 ng/ml). Coronary vasomotor dysfunction seemed to be related to these adverse events especially when the blood drug concentration was exceeding 20 ng/ml.