Retrospective Study of Patients Undergoing Percutaneous Intervention of the Transplant Renal Artery Stenosis (TRAS Study)

Renal transplantation is the standard treatment for patients with end-stage chronic kidney disease, as it is effective in reducing the morbidity and mortality of patients in this condition. Despite satisfactory results, some patients have graft dysfunction and difficult-to-control hypertension, with the main cause of transplanted renal artery stenosis (TRAS).

The incidence of TRAS varies from 1 to 23% in the various series in the literature, depending on the definition and diagnostic techniques used, most commonly occurring between the 3rd month and the 2nd year after transplantation. However, it may present at any time with refractory hypertension and / or graft dysfunction in the absence of rejection, ureteral obstruction or infection.

About 50% of TRAS cases occur at the anastomosis site and there seems to be no relationship with the type of anastomosis, whether end-to-end or end-to-side. TRAS is generally a consequence of clamp perfusion injury, incorrect suture technique, or fibrotic inflammatory reaction to suture material. Other factors attributed to TRAS are secondary to graft rejection, cytomegalovirus infection, and cadaveric donor graft. The last two factors are controversial in the literature. Late TRAS is related to progressive atherosclerosis.

The diagnosis of TRAS is made by clinical manifestations and / or by complementary exams. In addition to refractory hypertension, patients with TRAS may have increased serum creatinine, sudden graft deterioration and acute pulmonary edema. Color Doppler ultrasonography is the most commonly used method due to its easy access, low cost and does not require the use of contrast or radiolabels. However, its biggest limitation is the heavy reliance on operator expertise. It has a sensitivity of 87 to 94% and a specificity of 86 to 100%. TRAS is suspected when Doppler ultrasound has a peak systolic velocity (PSV) above 180 cm / s and a resistance index <0.50.

Computed tomography provides three-dimensional images that may be superior to those of selective angiography, with the advantage of not requiring arterial puncture and requiring less contrast. Nuclear magnetic resonance is even superior to tomography, with a sensitivity of 67 to 100% and specificity of 75 to 100%. However, its availability is still limited, besides presenting high costs.