Towards a New Horizon of Coronary Devices

By Wail Nammas, MD

With the growing concerns about the problem of stent thrombosis (ST) following drug-eluting stent (DES) implantation, especially occurring late (after 1 month) and very late (after 1 year), there emerged a need to search for novel intracoronary devices with improved safety profile.[1] Pathological studies demonstrated delayed arterial healing as the most important histopathological independent predictor of late ST following DES implantation, observed as the lack of endothelial coverage over stent struts.[2] It was reported that the most important clinical predictor of late ST following first-generation DES was the premature discontinuation of P2Y12 inhibitor.[3] This has led the two leading authorities of guidelines to extend the duration of dual antiplatelet therapy following DES implantation to 1 year.[4,5]

Neointimal healing response following stent implantation largely depicts long-term clinical and angiographic outcomes. In this regard, recent concerns have focused on incomplete neointimal coverage of stent struts. Recently, optical coherence tomography (OCT) has become the state-of-the-art for evaluation of neointimal coverage of stent struts in studies comparing different stent designs. Evidence supports that stent strut coverage measured by OCT correlates well with histological neointimal healing after stenting in animal models.[6,7]

One of the promising alternatives to DES is the titanium-nitride-oxide-coated bioactive stents (BAS). The safety of BAS was demonstrated in several reports from real-life unselected populations.[8,9] Recently, two randomized controlled trials compared the long-term outcome of BAS versus DES in patients presenting with acute coronary syndrome.[10,11] In the TITAX AMI trial, BAS were superior to paclitaxel-eluting stents for the primary composite endpoint of cardiac death, recurrent myocardial infarction (MI), and target lesion revascularization, at 5-year follow-up, in patients with acute MI.[10] In the BASE ACS trial, BAS were non-inferior to everolimus-eluting stents for the primary composite endpoint of cardiac death, non-fatal MI, and ischemia-driven target lesion revascularization, at 1-year follow-up, in patients presenting with the whole spectrum of acute coronary syndrome.[11]

In a prospective registry, we sought to explore the extent of neointimal coverage of stent struts by OCT and vasodilator response by coronary flow reserve (CFR) at 30 days following the implantation of titanium-nitride-oxide-coated BAS in an unselected non-diabetic population. Patients underwent OCT and CFR examination at an average of 30.5 ± 5.7 days following stent implantation. In these, 411 cross-sections were analyzed, including 3780 struts. Binary stent strut coverage was 97.2%, and the prevalence of malapposed struts was 3.2%. No thrombi were detected by OCT. CFR data were available in 12 patients. Mean CFR was 2.3 ± 0.5. We concluded that BAS implantation in an unselected non-diabetic cohort resulted in satisfactory binary stent strut coverage, with a low prevalence of malapposed struts, and a preserved vasodilator function in a good percentage of patients, as evaluated by OCT and CFR at 30-day follow-up.

RE: Vascular Healing Early After Titanium-Nitride-Oxide-Coated Stent Implantation Assessed by Optical Coherence Tomography    Antti-Pekka Annala, MD1*,  Tuomas Lehtinen, MD1,2*,  Tuomas O. Kiviniemi, MD1,2,  Antti Ylitalo, MD1, Wail Nammas, MD1,  Pasi P. Karjalainen, MD1        J INVASIVE CARDIOL 2013;25(4):186-189

References

  1. Daemen J, et al, Lancet 2007;369:667-78
  2. Finn AV, et al, Circulation 2007;115:2435-41
  3. Iakovou I, et al, JAMA 2005:293:2126-30
  4. Levine GN, et al, JACC 2011;58:e44-e122
  5. Wijns W, et al, Eur Heart J 2010;31:2501-55
  6. Murata A, et al. JACC Cardiovasc Imaging 2010;3:76–84.
  7. Templin C, et al. Eur Heart J 2010;31:1792–1801.
  8. Mosseri M, et al. Eurointervention 2006;2:192–196.
  9. Karjalainen PP, et al. J Interv Cardiol 2011;24:1–8.

10.Tuomainen PO, et al. Int J Cardiol 2012 (in press).

11.Karjalainen PP, et al. EuroIntervention 2012;8:306–315.

Dr. Nammas is the Assistant Professor of Cardiology at the Ain Shams University in Cairo, Egypt. He is a member of the European Society of Cardiology, the American Society of Echocardiography, the European Association of Percutaneous Coronary Intervention, the European Working Group on Acute Cardiac Care. He is a member of the Editorial Board of “Translational Medicine” and on the Advisory Board for the “Anatolian Journal of Cardiology.”

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Late Stent Thrombosis of a Second-Generation Drug-Eluting Stent   Pasi P. Karjalainen, MD, PhD, Wail Nammas, MD, PhD, Antti Ylitalo, MD, PhD

Very Late Stent Thrombosis Approximately 7 Years After Deployment and One-Week Cessation of Dual Antiplatelet Therapy    Jennifer E. Taylor-Sutton, PhD and Michael C. Kim, MD

Acute Myocardial Infarction Caused By Late Stent Thrombosis after Deployment of a Paclitaxel-eluting Stent   Woong Chol Kang, MD, Seung Hwan Han, MD, Kyung Rim Choi, MD, Tae Hoon Ahn, MD, Eak Kyun Shin, MD

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