Compliance of a cobalt chromium coronary stent alloy--the COVIS trial.

Background: Cobalt chromium coronary stents are increasingly being used in percutaneous coronary interventions. There are, however, no reliable data about the characteristics of unfolding and visibility of this stent alloy in vivo. The aim of this study is to compare cobalt chromium coronary stents with conventional stainless steel stents using intracoronary ultrasound.

Methods: Twenty de novo native coronary stenoses < or = 20 mm in length (target vessel reference diameter > or = 2.5 and < or = 4.0 mm) received under sequential intracoronary ultrasound either a cobalt chromium stent (Multi-Link Vision; n = 10) or a stainless steel stent (Multi-Link Zeta; n = 10).

Results: For optimal unfolding, the cobalt chromium stent requires a higher balloon deployment pressure (13.90 +/- 2.03 atm) than the stainless steel stent (11.50 +/- 2.12 atm). Furthermore, the achieved target vessel diameter of the cobalt chromium stent (Visibility-Index QCA/IVUS Multi-Link Vision 1.13 / Multi-Link Zeta 1.04) is more easily overrated by Quantitative Coronary Analysis.

Conclusion: These data indicate that stent material-specific recommendations for optimal implantation pressure and different stent material with an equal design should both be considered in interpreting QCA-analysis.