[Exercise-induced renal ischemia after kidney transplantation: report of two cases]

Renal transplant patients are high cardiovascular risk patients. Regular ultrasound surveillance of the renal transplant artery and the iliac artery upstream from the anastomosis is required to detect potential arterial stenosis. The purpose of this article was to illustrate the hemodynamic impact of exercise in such patients and the screening efficiency of Doppler ultrasound stress testing.

Two renal transplant patients were hospitalized in our center for impaired renal function, worsening hypertension, and intermittent claudication. This association of peripheral vascular disease and renal dysfunction led us to perform a Doppler ultrasound stress test to search for vascular stenosis upstream from the graft. Hemodynamic fluctuations in the ipsilateral leg were recorded during flexion-extension exercises.

Iliac artery lesions were found in both patients: the Doppler examination showed decreased systolic velocity in the graft artery during exercise, compatible with iliac steal syndrome. Surgical treatment was performed in both patients. After surgery, the control Doppler ultrasound stress test showed that systolic flow did not decline in the graft vessels during exercise. Renal function stabilized in one patient and improved in the other; claudication disappeared after surgery.

Doppler ultrasound stress testing can be a valuable tool for detecting exercise-induced renal graft ischemia in transplant patients. Its screening performance should be determined in a larger population before routine use.