Analysis of the relation between stent implantation pressure and expansion

Intravascular ultrasound (IVUS) imaging has demonstrated that most coronary stents implanted at low pressure are underexpanded.(1,2) Routine high-pressure dilatation typically results in greater stent dimensions,(1-4) which has been associated with improved late clinical and angiographic outcomes.(3-5) Numerous studies have now demonstrated that the predominant predictors of freedom from restenosis after stenting are the minimal luminal diameter (MLD) and area achieved.(6-9) Although high pressures are now routinely used to increase stent expansion, the relation between stent implantation pressure and luminal dimensions has not been rigorously studied, and the level of pressure used varies widely. Therefore, to examine the relation between implantation pressure, stent expansion, and the adequacy of stent deployment, a prospective, controlled study was performed in which stents were implanted and serially dilated in each lesion at 12, 15, and 18 atm, and evaluated at each pressure level with quantitative coronary angiography and IVUS, with independent core lab assessment. A secondary goal of the study was to determine whether IVUS has utility in assessing stent expansion (beyond angiography) if high pressures are routinely used.