Stent expansion in calcified coronary chronic total occlusions:  The impact of different stent platforms

To evaluate the stent expansion of the durable-polymer Zotarolimus-eluting stent (dp-ZES), the durable-polymer Everolimus-eluting stent (dp-EES), and the bioabsorbable-polymer Sirolimus-eluting stent (bp-SES) in calcified coronary chronic total occlusions (CTO).

The newer generation stents with ultrathin struts might raise concerns regarding reduced radial strength and higher stent recoil (SR) when implanted in calcified CTOs.

Between January 2017 and June 2021 consecutive patients with CTO undergoing percutaneous coronary intervention with dp-ZES, dp-EES, or bp-SES were evaluated. The analysis was performed in calcific and in noncalcific CTOs. Quantitative coronary angiography analysis was used to assess diameter stenosis (DS), absolute and relative SR, absolute and relative focal SR, absolute and relative balloon deficit (BD), and absolute and relative focal BD. The primary endpoint was DS.

A total of 213 CTOs were evaluated, 115 calcific CTOs (dp-ZES:25, dp-EES:29, bp-SES:61) and 98 non-calcific CTOs (dp-ZES:41, dp-EES:11, bp-SES:46). In calcific CTOs, residual DS was lower in dp-ZES than in dp-EES and bp-SES (-1.00% [-6.50-6.50] vs. 13.00% [7.0-19.00] vs. 15.00% [5.00-20.00]; p < 0.001). Dp-ZES was also an independent predictor of residual DS ≤ 10% (OR 11.34, 95% CI 2.6-49.43, p = 0.001). Absolute and relative focal SR and absolute and relative SR were similar between dp-ZES, dp-EES, and bp-SES (p = 0.913, p = 0.890, p = 0.518, p = 0.426, respectively). In noncalcified CTOs, the residual DS was similar in the three groups (p = 0.340). High relative focal SR was less frequent in dp-ZES than in dp-EES and in bp-SES (19.5% vs. 54.5% vs. 37.0%; p < 0.048).

The three stent platforms demonstrated an overall low residual DS when implanted in CTOs. However, dp-ZES was associated with the lowest residual DS and identified as independent predictor of residual DS ≤ 10% in patients with calcific CTOs. Dp-ZES was associated with a lower incidence of high relative focal stent recoil, in noncalcific CTOs. Balloon deficit might be considerate as a surrogate for stent expansion in calcified CTOs.