For risk of MI, the same type of gradient was observed. Relative to devices with thick struts, devices with ultrathin struts were associated with a 27% reduction, devices with thin struts were associated with a 21% reduction, and devices with struts of intermediate thickness were associated with a 15% reduction. Only the difference for the intermediate-thickness devices fell short of statistical significance.
There were 22 different stent devices represented in this analysis. Bare metal stents and stents with bioresorbable scaffolds were excluded, but devices from all three generations of drug-eluting stents, including devices with bioabsorbable polymers, were included.
Other outcomes, including mortality, cardiovascular mortality, and major adverse cardiovascular events, were evaluated, but a gradient relationship between strut thickness and these outcomes was less apparent. For example, when devices with thick struts were compared to devices with thinner struts, only the ultrathin devices achieved a significant, 15%, reduction in cardiovascular mortality. The 10% reduction in all-cause mortality fell short of statistical significance.
Emphasizing that other factors, such as stent geometry, polymer type, and type of eluting drug, were not considered in this analysis, Dr. Iantorno acknowledged that there are important limitations of this study, but the data are consistent with the hypothesis that “reducing strut thickness might be the key to improving the efficacy and safety profile of coronary stents.”