Renal transplant artery stenosis.

Renal transplant artery stenosis is a relatively frequent complication after transplantation, with an incidence of up to 23% being reported. The gold standard for the diagnosis still remains renal arteriography. Several imaging techniques are available to confirm the diagnosis (duplex-Doppler, nuclear magnetic resonance, spiral computerized tomography), and their use depends, in part, on the centre's experience. The treatment can either be conservative (providing graft perfusion is not jeopardized) or by revascularization (surgical or percutaneous transluminal angioplasty). There are several unresolved questions concerning revascularization of the graft: whether and when to intervene? Is the stenosis progressive in the long term? Is hypertension alone an indication for angioplasty? How do we assess the haemodynamic significance of the stenosis? What is a significant stenosis-50, 60, 80 or 90%? Is stenosis 'good' for something? In Slovenia, since 1990, all renal transplant recipients are screened regularly for the presence of stenosis by duplex-Doppler (performed by nephrologists), and also in cases of deterioration of graft function or hypertension. In the majority of patients with a diagnosed stenosis, the latter was found to be stable over time (assessed by regular Doppler, graft function and hypertension control). In some patients, spontaneous regression of the stenosis was observed. Frequent Doppler assessment of these patients helps to be more conservative with angioplasty and angiography. Deterioration of graft function (with stenosis diagnosed by Doppler) is the main indication for angiography (and angioplasty). Better definition of significant stenosis and randomized studies comparing conservative treatment vs angioplasty are warranted. Duplex-Doppler seems to be the ideal screening and follow-up test.