The characteristics of dissemination of embolic materials during renal artery stenting

Abstract

Though one of the major complications of renal artery stenting is dissemination of embolic materials which may cause deterioration of renal function, the characteristics of this phenomenon are unclear. We investigated the characteristics of embolization in renal artery stenting by intrarenal duplex ultrasound monitoring. A total of 17 patients with 21 lesions that underwent primary renal artery stenting were prospectively included. Intrarenal artery blood flow velocity spectra exhibiting microembolic signals (MES) were examined during renal artery intervention. Renal artery stenting was successful in all cases. Predilatation was needed in eight cases, and direct stenting without predilatation was performed in 13 cases. Postdilatation or flare formation was performed in 13 cases. Multiple stenting was not performed in any patients, though stenting of both renal arteries was performed in four cases. Major embolization and no reflow/slow flow were not determined by angiography. Except for one case of technical kidney failure, real-time intrarenal duplex ultrasound monitoring was possible and the study protocol was completed. MES were detected during all procedural phases. The number of cardiac beats with MES was significantly higher in stenting (11.1 +/- 2.8) following postdilatation/flare formation (8.3 +/- 4.1) than in predilatation (3.3 +/- 2.1) (predilatation vs. stenting: P < 0.001, predilatation vs. postdilatation/flare: P = 0.009, stenting vs. postdilatation/flare: P = 0.03). The mean creatinine value was 1.31 +/- 0.68 mg/dl at baseline and 1.54 +/- 1.08 at 1 month. Deterioration of renal function was observed in 43% (3/7) of patients with renal impairment, whereas 10% (1/10) of patients without renal impairment experienced deterioration of renal function (P = 0.250). Dissemination of embolic materials was detected in all procedures. Higher MES were detected in stenting following postdilatation/flare formation. Pre-existing renal impairment yielded a trend toward the deterioration of renal function after renal artery stenting during the short-term follow-up. Protected renal artery stenting might be considered advisable, at least in atherosclerotic renal artery stenosis patients with renal impairment though a larger number and long-term study will be required.