Therefore, it is logical to consider coating a metal stent with an agent that allows uniform coverage of both internal and external surfaces, does not increase the profile or affect deliverability of the device, remains stable during manipulation, allows rapid endothelialization and is biocompatible. This would prevent exposure of the stent metal to bloodstream and intimal surface. The recent advent of the BiodivYsio coated stent (Abbott Vascular Devices, Redwood City, CA) allows for the benefits of a balloon expandable stent implantation without the exposure of the thrombogenic bare metal. The phosphorylcholine (PC) coating on the stent, which acts as a passive barrier to prevent stainless steel exposure to the bloodstream or the intima of the blood vessel, is a hemocompatible polymer consisting of synthetic substances that mimic the body’s own naturally occurring chemical structure (found in the outermost membrane of red blood cells). The body does not detect stainless steel, but rather, PC, a biologically inert substance, thereby preventing platelet adhesion to the surface of metal struts and allowing effective endothelialization. Reducing the risk of thrombus formation (and possibly restenosis) is a strong argument for considering the PC-coated stent12.
While PC technology is effective in promoting positive short and long-term outcomes within the coronary arteries, the arterial access site is deserving of equal clinical concern. Achieving access site hemostasis in high-risk and highly anticoagulated patients has historically been performed outside of the catheterization lab, subjugating patients to lengthy, uncomfortable recovery periods while anticoagulation levels drop before sheath pulls can be performed safely. The use of a suture-mediated closure device (Perclose, Abbott Vascular Devices, Redwood city, CA) offers an alternative to delayed sheath removal that provides immediate, secure closure while the patient is still in the laboratory. Since the arteriotomy is secured using a suture allowing immediate tissue apposition, even high-risk patients are able to ambulate rapidly and discharge expediently. In addition, the fact that the arteriotomy site can be reaccessed, immediately and repeatedly, allows for multivessel, staged intervention.
The following case reports demonstrate the strategy of coronary revascularization using PC-coated stents followed by suture-mediated arteriotomy repair following expedited completion of procedure in high-risk patients.
Case Report 1
A 68-year-old Caucasian female presented with class III angina pectoris. Her past medical history was significant for hypertensive heart disease and Type II diabetes mellitus. Coronary angiography revealed high grade flow limiting lesion in the second obtuse marginal branch of the circumflex artery, measuring 11 mm in length (Figure 1). There was fluoroscopic evidence calcification at the site of stenosis. Additionally, the dominant right coronary artery had a high grade stenosis in the mid segment (Figure 2). The left ventricular function was mildly reduced with estimated left ventricular ejection fraction of 45%.
The patient was pretreated using aspirin, clopidogrel and an intravenous IIb/IIIa agent. A 2.5 mm, 20 mm long balloon was used to predilate the lesion in the obtuse marginal artery at 6 atm, followed by deployment of a 3.0 mm x 15 mm BiodivYsio AS stent at 12 atmosphere (Figure 3). The right coronary artery was treated using primary stenting with a 3.0 mm x 15 mm BiodivYsio AS stent at 14 atmospheres (Figure 4). The arteriotomy was repaired immediately post-procedure using suture-mediated closure (Perclose), allowing the patient to recover at 45 degrees post procedure and ambulate at 4 hours. The patient was discharged 18 hours post-stent.
At 7 months post stent procedure, the patient was evaluated for pre-operative cardiovascular clearance for abdominal surgery (due to an abnormal nuclear stress study). Coronary angiography revealed widely patent stents in both vessels with minimal intimal proliferation (Figures 5 and 6).
Case Report 2
A 72-year-old diabetic female with history of renal insufficiency (serum creatinine 2.9 mg/dl) and severe gastrointestinal bleed from colonic polyps presented with class III angina. Coronary angiography revealed a complex lesion in the mid left anterior descending artery and the first diagonal artery (Figure 7). Due to history of severe gastrointestinal bleeding, limited anticoagulation (3000 U of heparin, aspirin and clopidogrel, without intravenous IIb/IIIa antagonist) was utilized. A 3.0 mm x 15 mm BiodivYsio AS was deployed in the mid LAD lesion and a 2.5 mm x 15 mm BiodivYsio SV stent was placed in the diagonal (to bail out flow-limiting dissection) with excellent angiographic (Figure 8) and clinical results.
The lower thrombogenicity of the PC-coated stent is particularly advantageous in situations where excessive anticoagulation is prohibited by risk of serious bleeding. The arteriotomy was repaired using Perclose. At 4-month follow-up, the patient is functional class I with no evidence of clinical restenosis.
Conclusion
The BiodivYsio stent offers the advantage of PC technology (thereby reducing the risk of subacute thrombosis in high-risk patients) in addition to a newer generation stent that offers excellent deliverability and scaffolding. The thin stent struts may offer advantage of lower restenosis rates13.
In the era of aggressive anticoagulation, immediate and effective repair of arteriotomy using suture-mediated closure allows early patient ambulation and increases patient comfort. A combination of a less thrombogenic stent with effective hemostasis allows clinicians to provide definitive coronary intervention and expedient recovery. Whether the combination of a less thrombogenic stent and suture-mediated closure would improve short and long term outcome and reduce post-procedure vascular complications compared to traditional methods of sheath removal needs further evaluation in larger prospective trials.
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