DOI: 10.1177/15266028261502671 ISSN: 1526-6028

Bare-Metal vs Covered Balloon-Expandable Stents for Transplant Renal Artery Stenosis: A Retrospective Comparative Study

Andrea Discalzi, Enrico Sanna, Maria Antonella Ruffino, Matilde Mandolini, Floriana Nardelli, Jacopo Brino, Thaira Albarello, Caterina Tallia, Marco Calandri, Luigi Biancone
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Purpose:

To compare short- and long-term outcomes of bare-metal (BMS) vs covered (CS) balloon-expandable stents in transplant renal artery stenosis (TRAS).

Materials and Methods:

This retrospective study evaluated patients who underwent elective stent placement for TRAS between 2016 and 2023. Short-term efficacy was assessed by clinical improvement (resolution of resistant hypertension/hypervolemia) and reduction in serum creatinine (sCr) within 14 days post-procedure. Long-term outcomes included Doppler ultrasound parameters – peak systolic velocity (PSV), acceleration time (AT) and resistive index (RI) – and restenosis/occlusion rates requiring or not intervention. Graft survival at the latest follow-up was recorded.

Results:

A total of 40 patients (mean age 58 ± 13 years, 68% male) were treated with BMS (n = 31) or CS (n = 9). Clinical improvement was observed in 71% of BMS and 83% of CS patients ( P  = 1.00). Median sCr decreased by 26% and 33% in BMS and CS patients, respectively ( P  = .30). At a median follow-up of 29 months, there were no statistically significant differences between groups in median PSV reduction (47% BMS vs 47% CS; P  = .44), AT improvement (36% BMS vs 25% CS; P  = .38) or RI increase (15% BMS vs 33% CS; P  = .12). In the BMS group, 2 cases of in-stent restenosis occurred (6.5%). In the CS group, 1 stent occlusion occurred (11%), resulting in graft loss. At final follow-up, overall graft survival was 85%.

Conclusion:

In this pilot study, BMS and CS showed no significant differences in TRAS outcomes. Further studies are warranted to better guide stent selection.

Clinical Impact

In transplant renal artery stenosis, balloon-expandable covered stents achieved clinical, biochemical and Doppler outcomes comparable to bare-metal stents, despite being used in more complex, atherosclerotic and longer lesions. This first direct comparison suggests that covered stents may be a reasonable option when heavy calcification, a friable wall or mural thrombus raise concern for embolisation or rupture, while bare-metal stents remain appropriate for most lesions. The single late covered-stent occlusion with graft loss highlights the need for careful platform selection and antiplatelet management. These pilot data should inform adequately powered multicentre registries rather than directly change practice.

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