Use of a Custom-made Polytetrafluoroethylene-covered Stent System for the Treatment of a Coronary Aneurysm Involving a Bifurcati

Atherosclerotic coronary artery disease is infrequently associated with ectasia and aneurysms due to extreme positive remodelling.¹ Coronary artery aneurysms have been excluded with coil embolization, autologous saphenous vein-covered stent grafts, and polytetrafluoroethylene (PTFE)-covered grafts.^1–4 However, severe coronary aneurysms may pose technical challenges to interventional cardiologists, especially when they involve bifurcations and the ostia of major branches. We hereby report one case of a coronary aneurysm involving a bifurcation which was successfully treated by a custom-made PTFE-covered bifurcation stent. Case Report. A 64-year-old man with a history of previous myocardial infarction (MI) underwent coronary angiography due to ischemia in the anterior wall evaluated with a thallium stress test. Coronary angiography revealed single-vessel coronary artery disease and a large aneurysm of the proximal left anterior descending coronary artery (LAD), as well as the ostium of a major diagonal branch and a septal branch with a significant stenosis at the main branch proximally to the aneurysm (Figure 1 A and B). The usual approach to exclude a coronary aneurysm is a technique that involves deployment of a covered stent to be anchored from the distal to the proximal non-aneurysmatic segments of the artery. However, due to the involvement of the bifurcation, we used a novel custom-made bifurcation stent system. The system was prepared in the catheterization laboratory as follows: a 3.5 x 19 mm JoStent® coronary stent graft (Jomed, Helsingborg, Sweden) was expanded and with a surgical blade, an opening was created in the mid-section of the stent. The opening involved a full cell of the stent. Through this opening, a 1.5 mm coaxial balloon was sandwiched with a 3.5 mm delivery balloon. The 1.5 mm balloon slightly protruded with its tip from the created side opening in the PTFE-covered stent. The system was advanced over 2 guidewires (one in the main branch and the other in the side branch) at the level of the bifurcation until the side balloon (1.5 mm) started to protrude into the diagonal branch. The stent was then delivered by inflating each balloon separately and then together (Figure 2A). The results were optimized with a final kissing balloon inflation by using a 2.5 x 20 mm semi-compliant balloon in the side branch at 12 atm (Boston Scientific, Scimed, Maple Grove, Minnesota) and another Maverick 3.0 x 20 mm balloon in the main branch at 12 atm (Figure 2B). Due to the good final angiographic result, no stent was implanted in the side branch. The covered stent system closed the entrance of the aneurysm and partially closed the exit toward the diagonal. The final angiogram revealed a good result and the aneurysm appeared almost completely excluded in the absence of significant stenosis (Figure 3A). The postprocedure course was uneventful and the patient was discharged on aspirin indefinitely and clopidogrel for one year. He had an uneventful six-month follow-up when he returned for an elective angiogram. The aneurysm appeared completely excluded with a 58% stenosis (assessed by quantitative coronary angiography) at the proximal edge of the covered stent (Figure 3B). Since the patient was asymptomatic, this lesion was left untreated. Discussion. Coronary artery aneurysms are a rare disorder characterized by abnormal dilatation (greater than 1.5 times the normal artery) of a localized portion or diffuse segments of coronary artery.^1,2 Angiographically detected coronary aneurysms have an incidence of 0.3–4.9% among patients undergoing coronary angiography.^1–4 This infrequent coronary lesion is commonly due to atherosclerosis, systemic disorders (e.g. Kawasaki syndrome, Ehlers-Danlos syndrome), or post-percutaneous interventions. Ischemic symptoms in such patients may be due to thrombosis, distal embolization, or high-grade stenosis.^3,4 Aneurysm perforation is another rare but devastating complication.^3,4 The usual approach to exclude a coronary aneurysm is a technique which involves the deployment of a covered stent to be anchored from the distal to the proximal non-aneurysmatic segments of the artery.^5–7 The PTFE-covered stent is an ultra thin, expandable, biocompatible PTFE layer sandwiched in between two coaxial 316 L stainless steel stents. However, side branch occlusion is an important limitation of the PTFE-covered stent graft in native coronary artery indications and is associated with increased rates of non-Q-wave MI and Q-wave MI.8 In our case, the aneurysm involved the bifurcation of the LAD with a diagonal branch. Due to the lack of availability of dedicated bifurcation systems with PTFE-covered stents, we used a custom-made PTFE-covered stent with a custom-made side opening. The use of a pre-mounted balloon crossing the PTFE-covered stent enabled optimal deployment of the stent in the main branch, together with dilatation of the side branch, maintaining patency of its ostium. Final kissing balloon was also performed in order to achieve full expansion of both the PTFE-covered stent and the side branch. Despite our promising results, extreme caution should be exercised to avoid disrupting the geometry of the PTFE-covered stent during the preparation of the described system and to ensure safe usage of this custom-made device. We recently reported the exclusion of a coronary aneurysm involving bifurcation with a similar methodology by using a custom-made PTFE-covered bifurcation stent system.⁹ In the current report, we employed a modification of this technique. The difference between the two cases is that in the previous report, a bare metal stent was advanced through the opening of the side branch to cover a suboptimal result at the side branch, while in the current study, a stent was not advanced due to the optimal immediate result at the side branch. However, as in the previous report, we did advance a balloon through this opening and performed a kissing balloon inflation with a balloon in the main branch. We believe that a system employing two stents might provide better lesion coverage, but obviously at the price of increased profile. Instead, the PTFE-covered stent plus side branch balloon system warrants adequate dilatation, but with greater deliverability. Finally, our findings may be extrapolated and further application of this approach might be envisaged, such as a bifurcation stent system with two PTFE-covered stents, or a system combining a PTFE-covered stent with a drug-eluting stent. In conclusion, successful percutaneous intervention to seal an aneurysm involving bifurcation can be achieved with the use of a custom-made covered stent system. worawutkeak@yahoo.com

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