Impact of the Cross-Sectional Geometry of the Post-Deployment Coronary Stent on In-Stent Neointimal Hyperplasia. An Intravascular Ultrasound Study.

Abstract

n-stent neointimal hyperplasia (INH) is the main cause of restenosis after stenting 1 and several mechanisms have been proposed as determinants of the degree of in-stent neointimal proliferation: the amount of residual plaque burden; 2 the degree of rupture or dissection of the vessel wall after balloon dilation; 3 the aggressiveness of the stent implantation technique; 4 the degree of overexpansion or oversizing of the balloon; 5,6 multiple stents; 7 high acute gain; 7,8 high inflation pressure; 7,9 length of the stenosis; 7 small reference diameter; 7 small stent size; 10,11 and stent design. 12-14 Among these reports, Garasic et al documented the effect of local stent geometry on INH in rabbit arteries, 13 but there are no reports on the role of local stent geometry in intimal hyperplasia in human coronary arteries in vivo.Intravascular ultrasound (IVUS) can visualize INH in vivo, so it was used in the present study to examine the relationship between the cross-sectional geometry of the post-deployment coronary stent and the degree of INH. Circulation Journal Vol.66, May 2002 Methods Patient SelectionTwenty-three patients (13 men, 10 women; 63±10 years old, range, 31-79 years) with coronary stents (13 Multilink, 10 GFX stents) were selected and underwent follow-up cardiac catheterization at approximately 6 months (mean, 6.5±1.1 months) after stent implantation between 1997 and 2000. Exclusion criteria included a stented left main coronary artery, extreme tortuosity of the lesions, additional cardiac events during the 6 months since implantation, lesions with calcification of more than a 90°arc, lesions with poor IVUS image quality because of significant dropout, artifact and/or non-uniform rotational distortion, lesions wedged with a IVUS catheter. All stents had been deployed with an expanded balloon pressure of 10 atm.The study was approved by the Institutional Review Board of Clinical Research of Yamaguchi University. All patients gave informed written consent before IVUS imaging. IVUS ImagingFollow-up IVUS images were obtained with a 3.2 or 2.6Fr short monorail imaging catheter (30MHz Ultracross  and/or 40 MHz Discovery  or Atlantis  /Boston Scientific, Natick, MA, USA). Therapeutic anticoagulation was achieved with 5,000 IU heparin iv. Intracoronary isosorbide dinitrate (1.0 mg) was administered just before IVUS imaging. The transducer was then advanced as distally as possible, after To establish the relationship between the cross-sectional geometry of the post-deployment stent and the degree of in-stent neointimal hyperplasia (INH), intravascular ultrasound (IVUS) was used to examine cross-sections of the coronary arteries from 23 patients with coronary stents 6 months after implantation. Stent cross-sectional area (Sa) and stent perimeter (Sp) from 200 stent cross-sections, and the stent radius (Sr) and thickness of INH (Id) of 2,880 radial axes, were measured, and the mean degree of roundness (Rd) of stent cross-section was calculated for each stent as Rd = 4 Sa / Sp 2 . The degree of deformity (Df...

Alterations in wall shear stress predict sites of neointimal hyperplasia after stent implantation in rabbit iliac arteries

“…However, few studies have examined detailed time-and space-dependent distributions of WSS or attempted to correlate these alterations in WSS with neointimal hyperplasia after stent implantation in vivo. Moreover, it is well known that restenosis varies with stent geometry (11,32,35,50), but the geometric influence of stent properties on spatial and temporal WSS patterns has not been thoroughly investigated. Thus we tested the hypothesis that local alterations in spatial WSS associated with stent implantation temporally predict sites of neointimal hyperplasia in vivo.…”

Ultrasonic Tissue Characterization of the Atherosclerotic Carotid Artery-Histological Correlates of Carotid Integrated Backscatter-

“…2,3 It is well known that the degree of coronary stenosis is not related to the likelihood of myocardial infarction, and that pre-infarction coronary stenosis is found in less than 75% of the patients with myocardial infarction. 4 Acute coronary syndromes and acute cerebral infarction are caused in most cases by plaque rupture, and therefore, it is particularly important to assess the stability of the plaque.…”

Directional atherectomy before stenting versus stenting alone in percutaneous coronary interventions: A meta-analysis

“…Second, Prati et al demonstrated that residual plaque burden after stenting measured by IVUS is a major determinant of restenosis; thus, DCA might reduce post stenting plaque burden by mechanically cutting plaque material [2]. Third, the rounded cross section obtained after atherectomy has been associated with lower neointimal proliferation [17]. In our metaanalysis patients treated by DCA plus stenting exhibited a higher acute gain than patients treated by stent alone, thus suggesting that the utilization of larger stents played an important role in determining the lower restenosis or TLR rate, in spite of a similar late loss.…”