Novel Applications of Noncardiac Vascular Devices for the Treatment of Coronary Artery Pathology

From the Division of Cardiology and the ^*Department of Neurological Surgery, Columbia University Medical Center, New York, New York. Disclosures: Dr. Gray discloses that he is a consultant to Abbott Vascular, Boston Scientific Corp., Medtronic, Inc., and Cordis Corp. He has also received research grants from Abbott Vascular, Cordis and Medtronic. Dr. Moses reports that he has received speaker honoraria from Abbott Vascular, Boston Scientific Corporation, and Cordis Corporation. Manuscript submitted July 2, 2008, provisional acceptance given July 14, 2008, final version accepted August 6, 2008. Address for correspondence: Srinivas Iyengar, MD, Clinical Instructor, Division of Cardiology, Columbia University Medical Center, 161 Fort Washington Avenue, HIP 5th floor, New York, NY 10032. E-mail: si2177@columbia.edu

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ABSTRACT: Transcatheter percutaneous therapy for the treatment of vascular disease has markedly expanded over the last 20 years. This growth of endovascular technology has encouraged application of these modalities to vascular pathology in numerous territories that are not optimally suited for open-surgical techniques. Though the initial development and use of these devices was directed towards specific vascular beds (i.e., coronary, peripheral, cerebro-vascular), it is becoming increasingly apparent that these devices can be effectively used in alternate situations when clinically indicated. We describe two cases of nontraditional uses of noncoronary devices (specifically biliary self-expanding stents and neurovascular coils) in patients with coronary artery pathology.

J INVASIVE CARDIOL 2009;21:60–64

Key words: self-expanding stent, vascular coil, coronary

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Application of minimally-invasive techniques to treat vascular disease has accelerated over the last two decades. Within interventional cardiology, technological improvements in catheter delivery systems have facilitated the treatment of a wide spectrum of disease, however, the available coronary equipment is not always well-suited to the interventional requirements. However, devices developed for treatment in other vascular beds may have great value in specific coronary applications. We present two cases of coronary pathology successfully treated through the offlabel application of noncoronary devices. Case 1. A 38-year-old non-smoking female presented to her primary care physician with complaints of episodes of severe chest pain that radiated to her left arm with associated nausea which had increased over a period of 3 weeks. The patient underwent an exercise nuclear stress test which revealed a fixed lateral wall defect with an ejection fraction (EF) of approximately 58% (consistent with a previous myocardial infarction [MI]). The patient was managed conservatively, but continued to experience chest pain and was admitted to an outside hospital where she was found to have a non-Q wave MI. She then underwent cardiac catheterization which showed normal left main, left anterior descending (LAD), and right coronary arteries. The left circumflex (LCX) artery revealed subtotal occlusion of the obtuse marginal-1 (OM1) artery with possible spontaneous dissection. Her EF remained normal, and she was managed conservatively, with plans for a possible percutaneous coronary intervention (PCI) if symptoms worsened. Due to ongoing symptomatology and a small enzyme release, the patient again underwent coronary angiography 3 weeks later at which time there appeared to be focal aneurysmal dilatation of the OM1 lesion. The patient was referred to our institution for high-risk PCI of the OM1 fusiform aneurysm. After review of her angiograms and further discussion with the patient, along with discussion with our neuroradiologist (PM), she was admitted for percutaneous intervention. Following sterile preparation and draping, administration of 2% lidocaine anesthesia, a 7 Fr sheath was introduced into the left femoral artery. A 7 Fr EBU 3.5 100 cm coronary guide catheter was used to intubate the left coronary artery (LCA). Anticoagulation was achieved using a weight-based heparin bolus. Initial coronary angiographic views demonstrated the size and location of the lesion in question (Figures 1 and 2). Analysis of the aneurysm morphology revealed a wide-neck origin from the OM1. For endovascular occlusion of the aneurysm, some form of vascular reconstructive device would be necessary to prevent coil prolapse into the parent artery. Options included a bare-metal stent such as is used to complement wide-neck cerebral aneurysms. A second option was to deploy a covered stent, but this was rejected due to the small vessel size, the likelihood that the stent would cover the atrioventricular groove continuation of the CX artery, and the issues of acute thrombosis and long-term patency. As a last resort, coil occlusion of the vessel proximal to the aneurysm was also considered. Under direct fluoroscopic guidance, a 0.014 inch x 300 cm Asahi Prowater guidewire (Abbott Vascular, Abbott Park, Illinois) was placed in the distal OM1 artery across the aneurysm. A Prowler 14 microcatheter (JNJ Cordis Neurovascular, Miami Lakes, Florida) was placed into the fundus of the aneurysm utilizing a 0.014 inch x 205 cm Transend EX guidewire (Boston Scientific Corp., Natick, Massachusetts). The Transend guidewire was then removed, and the catheter position was maintained within the aneurysm. At this point, a Neuroform™ 3.0 x 15 mm self-expanding nitinol stent (Boston Scientific) was deployed in the OM1 over the Prowater guidewire symmetrically across the aneurysm base, thus trapping the Prowler catheter in the aneurysm. Once the stent was deployed, a 3.0 mm x 3.0 cm Trufill DCS Orbit detachable platinum microcoil (JNJ Cordis Neurovascular) was placed in the fundus of the aneurysm through the Prowler catheter (Figure 3). Once the appropriate position was determined, the coil was hydraulically detached. Next, a 2.0 mm x 4.0 cm Trufill DCS Orbit detachable coil was placed and detached in a similar fashion (Figure 4). The Prowler catheter was then removed from behind the stent without difficulty, and final angiographic views were obtained (Figures 5 and 6). Access-site hemostasis was achieved using a StarClose™ device (Abbott Vascular). The patient was stable and had no complaints of chest pain or related symptoms post procedure. She was discharged uneventfully the next day with prescriptions for aspirin 325 mg p.o. daily and clopidogrel 75 mg p.o. daily for 1 month. At that time, the patient was instructed to reduce her aspirin to 81 mg p.o. daily. She underwent a follow-up exercise nuclear stress test 1 month after the procedure. The results revealed no inducible ischemia, a fixed defect in the lateral wall and an EF of 66%. She was able to achieve 95% of her predicted maximum heart rate and did not have any symptoms during the test. Additional aneurysm surveillance using cerebral magnetic resonance angiography (MRA) revealed no evidence of cerebral aneurysm or other vascular malformation. She has since remained asymptomatic and chest pain-free. Case 2. A 43-year-old female who had recently given birth via C-section presented to her primary care physician’s office 2 weeks after hospital discharge with complaints of orthopnea and increasing lower-extremity edema. The patient was hemodynamically stable and tests to rule out post-partum eclampsia (complete blood count, urinalysis, liver function tests, etc.) were negative. She had an electrocardiogram (ECG) performed which revealed new anterolateral T-wave inversions. The patient was referred to an outside hospital for further evaluation. She was found to have a positive troponin which peaked at 1.1 and a pro-brain natriuretic peptide (BNP) level of 5,180. A transthoracic echocardiogram (TTE) was performed which showed anteroseptal hypokinesis, mild mitral regurgitation, with a mildly hypertrophied left ventricle and a EF of 45%. A spiral CT was also performed which was negative for pulmonary embolism. After diuresis, the patient underwent cardiac catheterization which revealed a normal-caliber LAD, with dissection extending from the ostium to the mid-portion of the vessel, that appeared otherwise normal. The right and CX arteries were of normal caliber, without evidence of coronary artery disease angiographically. The EF was approximately 40%. The patient was transferred to our facility for further evaluation and PCI to treat her peri-partum spontaneous coronary dissection. The patient was brought to our catheterization laboratory. Following sterile preparation and draping, administration of 2% lidocaine anesthesia, an 8 Fr vascular sheath was introduced to the left femoral artery. The LCA was intubated with an 8 Fr JL 4 100 cm coronary guide catheter. Anticoagulation was achieved using a weight-based heparin bolus. Initial angiographic views demonstrated the presence of a linear dissection in the ostial/proximal LAD (Figures 7 and 8). A 0.014 inch x 190 cm Universal BMW coronary guidewire (Guidant Corp., Indianapolis, Indiana) was advanced to the distal LCX. A 2nd 0.014 inch x 190 cm Universal BMW wire was carefully advanced across the lesion to the distal LAD. Intravascular ultrasound (IVUS) of the LAD was performed utilizing a Boston Scientific Atlantis 2.5 Fr x 135 cm catheter and an iLab IVUS imaging system (Boston Scientific). Pre-stent true lumen minimal lumen diameter (MLD) and the lumen cross-sectional area (LCSA) of the proximal LAD were 0.65 mm and 3.81 mm², respectively. Given the relatively large size of the vessel, the length and nonatherosclerotic nature of the lesion, and the desire to avoid the barotrauma requisite in a balloon-expandable stent implantation, an Xpert 5.0 x 20 mm self-expanding nitinol stent (Abbott Vascular) was chosen as primary therapy (Figure 9). The stent was deployed from the LAD ostium to the mid-vessel without use of balloon angioplasty; angiography post-stent deployment demonstrated complete resolution of the dissection. IVUS was repeated and confirmed these findings, with a post-MLD and LCSA of 4.22 mm and 15.9 mm², respectively, and no residual dissection flap or false lumen. Coronary wires were removed and final angiographic cine images were obtained (Figures 10 and 11). After removal of the guide catheter, vascular hemostasis was achieved utilizing a Perclose closure device (Abbott Vascular). The patient tolerated the procedure well. She was discharged 3 days after admission on aspirin 325 mg p.o. daily and clopidogrel 75 mg p.o. daily for 1 month. After 1 month had elapsed, the patient was instructed to reduce her aspirin to 81 mg p.o. daily and to undergo a follow-up cardiac angiogram in 6 months’ time. At approximately 3 months post PCI, the patient underwent a TTE which revealed an improved/normalized EF of 55% with no gross valvular abnormalities. Cerebral MRA was also performed in the interim, given her history of coronary dissection and the recent onset of headaches, and revealed no cerebrovascular abnormalities. The patient had indicated that she still experienced occasional atypical chest pressure with left arm numbness, but significantly less discomfort since the stent implantation. At 6 months post PCI, the patient underwent repeat coronary angiography and IVUS evaluation. Angiographic images of the LAD demonstrated a widely patent vessel with no in-stent restenosis of the ostial/proximal/mid-segment and no progression of disease elsewhere in the LCA (Figures 12 and 13). IVUS measurements revealed an MLD and LCSA of 3.95 mm and 15.03 mm2, respectively. The patient tolerated the procedure without complications and was discharged the following day.

Discussion

These two case reports demonstrate the successful management of unusual coronary pathology by the judicious use of noncoronary devices borrowed from other territories of typical application: cerebrovascular and biliary. The first case dealt with the use of a neurovascular stent-assisted detachable coil occlusion to treat a saccular aneurysm of the coronary circulation. Initially, the use of coil embolization for the treatment of aneurysms was primarily used in intracranial vessels, beginning in 1991 with the introduction of the platinum Gugliemi detachable coils (Boston Scientific).¹ These original Gugliemi coils relied on electrolysis for detachment of their platinum microcoils. Long-term results utilizing these coils have been clinically favorable in this specific vascular bed.^2,3 Given the growth of this particular area for new devices, a number of alternative methods of deployment (other than with electrolysis) have been developed. In our report, the use of hydraulic pressure produced by an insufflator to facilitate coil release was the method employed. Initially, prior to stent technology, balloon-assisted coil deployment in the cerebrovasculature represented a viable treatment strategy. Balloon-neck remodeling still has applicability in the cerebral circulation, and it avoids deployment of a stent requiring dual antiplatelet therapy, which is a vexing problem in cerebrovascular disease due to the risk of hemorrhage. Utilized in the coronary circulation, however, stent-assisted scaffolding provides less alteration of coronary blood flow, and thus potentially less ischemia and risk of arrhythmia. Additionally, the coronary artery aneurysm in patient #1 was of a fusiform morphology with a significant portion of the parent artery involved. Given the dynamic nature of the coronary vasculature compared with the stationary cerebral vasculature, there is concern that the balloon-only method could result in subacute prolapse of the coils into the parent artery, thereby resulting in post-procedural occlusion and MI. The introduction of the Neuroform self-expanding stent has allowed treatment of broad-neck and fusiform cerebral aneurysms not previously amenable to endovascular techniques.^4,5 Applications of these devices to the coronary circulation, however, have been less well-elucidated in the literature. Although the indications for treatment of coronary aneurysms are not clearly defined, there are reported data demonstrating an overall 5-year survival rate of only 71% in patients with untreated coronary aneurysms (generally in patients with primary atherosclerotic disease).⁶ There have been reported case series primarily using the balloon-expandable stent-assisted coil embolization technique to treat pseudo-aneurysms in the coronary circulation.⁷ However, the approach described herein differs in that a cerebrovascular self-expanding, rather than a balloon-expandable, stent was employed. This neurointerventional technique may help to ensure proper positioning of the coils via a secure catheter position prior to stent deployment. It is essential that patients who receive vascular devices for offlabel uses undergo close clinical and angiographic follow up. Our patient became, and remained, asymptomatic after coil embolization and therefore refused angiographic follow up despite several attempts to arrange it. The lack of any clinical signs of restenosis noted in this patient follows prior experiences in treating aneurysms in the cerebral circulation, demonstrating the low overall rates of restenosis with these devices for this indication.⁴ Our second case involved the treatment of a peripartum spontaneous coronary dissection. Though MI with subsequent coronary dissection during the time of pregnancy occurs infrequently,^8–10 it can be associated with disastrous outcomes. Additionally, these patients can suffer not only from coronary vascular derangements, but cerebrovascular involvement as well.¹¹ It is unclear whether it is the physical stress of pregnancy coupled with hormonal changes that lead to changes in the coronary vascular endothelium, or an acceleration of an already present atherosclerotic process that results in dissection. In Patient #2, the dissection was of significant length and width and caused marked luminal obstruction, which ultimately resulted in abnormalities in ventricular function. Given the lack of atherosclerotic or obstructive CAD, along with the desire to minimize procedural trauma in an already fragile vessel, a nontraditional self-expanding biliary stent on a low-profile 4 Fr delivery system well-matched to coronary guiding equipment, was chosen to seal the dissection flap. The use of self-expanding stents in the coronary circulation has been described both in native vessels and in saphenous vein grafts (SVGs),^12,13 although to our knowledge, this is the first report of an Xpert nitinol self-expanding biliary stent used to treat a native coronary peripartum dissection.

Conclusions

The use of noncardiac vascular devices for coronary artery pathology is an area where there has been a significant amount of interest over the last decade. Historically, the majority of data relating to the use of these tools in this setting has been largely made up of case reports and anecdotal evidence. Given the continuous technological advances of percutaneous therapy for vascular disease, along with the expanding skill sets of operators from various disciplines, it appears a natural progression that certain devices initially studied in alternate vascular beds could have multiple systemic applications. Given the offlabel use of these devices and unknown long-term prognosis, clinical and angiographic follow up is strongly endorsed when possible. As we have demonstrated in these two case reports, proper utilization of these devices in the appropriate clinical context can produce both short- and long-term favorable results and could potentially add to the armamentarium for the practicing interventional cardiologist. Additionally, collaboration between interventional specialties, in this instance neurointerventional radiology, expands the available repertoire of devices and expertise.

References

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