Spontaneous Left Anterior Descending Coronary Artery Dissection in a Patient with Neurofibromatosis

ABSTRACT: Neurofibromatosis (NF) is a genetic disorder inherited in an autosomal dominant pattern. Subtypes I and II are the most well recognized, and among these, Type I has associated vasculopathy. Less than 3% of patients have vascular involvement, with the renal artery as the most commonly involved vessel. Dissection and rupture of aneurysms in larger arteries such as the subclavian and the aorta have been previously reported. This is the first reported case of a spontaneous coronary artery dissection in a patient with NF-I. Imperative in the percutaneous treatment of coronary artery dissections is early recognition and proactive decision making. Recognition of a possible association between NF and coronary dissections will further facilitate successful and prompt management of this otherwise rare entity.

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J INVASIVE CARDIOL 2009;21:e103–e105 Key words: Coronary artery dissection, neurofibromatosis, von Recklinghausen’s disease, acute coronary syndrome, ST-segment myocardial elevation, percutaneous intervention Case Presentation. A 58-year-old female with a past medical history significant for neurofibromatosis Type I, and hypothyroidism presented to an outside rural referral hospital with substernal chest discomfort for the past hour. Associated symptoms included nausea and dyspnea. A 12-lead electrocardiogram demonstrated normal sinus rhythm with 2 mm of ST-segment elevation in leads II, III, aVF and V4–V6. She was given 4 baby aspirin to chew and swallow followed by intravenous heparin bolus of 4,000 Units and tenecteplase. There was incomplete resolution of the ST-segment elevation and ongoing chest discomfort. She was emergently transferred to our facility for rescue percutaneous coronary intervention. On arrival, she was in no acute distress and was chest pain-free, albeit on a nitroglycerin drip. She was afebrile, with a heart rate of 82 beats per minute and a blood pressure of 125/85. First and second heart sounds were normal and there were no murmurs, rubs or gallops on cardiac auscultation. Lungs were clear bilaterally. Thorough physical exam after the cardiac catheterization was remarkable for the presence of multiple cutaneous neurofibromas (Figure 1). Coronary angiography demonstrated no evidence of obstructive disease in the left main stem, left circumflex or the dominant right coronary artery. Angiography of the left anterior descending artery (LAD) demonstrated a smooth artery with a dissection originating in the proximal LAD that spiraled to the distal LAD where the vessel was then occluded (Figure 2). The patient was anticoagulated with bivalirudin. An XB 3.5 6 Fr Guide® (Cordis Corp., Miami Lakes, Florida) was used to engage the left main artery. An initial Asahi ProwaterFlex wire (Abbott Vascular, Abbott Park, Illinois) was easily advanced to the site of distal occlusion in the LAD, but the wire could not be advanced to the apex. A Maverick 2.0 x 15 mm balloon (Boston Scientific Corp., Natick, Massachusetts) was advanced over the wire and gentle contrast injection through the balloon confirmed the location to be in the false lumen of a dissection plane. A second Asahi ProwaterFlex wire was advanced into the very apex of the LAD, with the initial wire left in place. A second Maverick 2.0 x 15 mm balloon was advanced over this second wire and contrast injection through the balloon now demonstrated intraluminal position with good downstream opacification of the apical LAD (Figure 3). The LAD was then stented with overlapping drug-eluting stents placed distal-proximal using a 2.50 x 14 mm Endeavor® (Medtronic, Inc., Minneapolis, Minnesota), a 2.50 x 30 mm Endeavor, a 3.0 x 30 Endeavor and a 3.5 x 33 mm Cypher® (Cordis). The stented segment was postdilated from 3.2 mm distally to 4.2 mm proximally. Final contrast angiography demonstrated 0% residual stenosis and thrombolysis in myocardial infarction (TIMI)-3 flow throughout the LAD. The first diagonal branch had normal flow, but evidence of dissection as well, which was left alone. Left ventriculography demonstrated an estimated ejection fraction of 35%, with mid-to-distal anterior wall hypokinesis. Right femoral artery hemostasis was accomplished via deployment of a StarClose closure device (Abbott Vascular). The patient remained hemodynamically stable throughout the procedure and her chest discomfort resolved. She was admitted to the coronary care unit and had an uneventful subsequent hospital stay. She was discharged home in stable condition on day-four. Discussion. Coronary artery dissections are broadly differentiated into two categories: spontaneous or iatrogenic. Iatrogenic dissections are an uncommon complication of coronary angiography and intervention with an unknown, but relatively rare overall incidence. Identified risk factors for catheter-induced dissection include left main stem disease, arterial calcification, use of Amplatz-shaped catheters and the presentation of acute myocardial infarction.1 Although the exact mechanism of catheter-induced dissection may vary, deep-vessel intubation, vigorous contrast injection (particularly during a dampened or ventricularized pressure tracing) and aggressive torquing of the catheter can lead to vessel trauma and antegrade or retrograde propagation of the dissection. Angiographic predictors of angioplasty-induced dissection include calcified lesions, eccentric lesions, long lesions, complex lesion morphology, severe vessel tortuosity and balloon-to-artery ratio > 1.2.19,20 Spontaneous coronary artery dissections are an uncommon cause of acute coronary syndrome, with fewer than 200 reported cases in the literature.2 They have been defined as coronary artery dissection in the absence of aortic dissection or provoking factors such as coronary angiography or angioplasty, and the reported incidence is between 0.04 and 0.2%.3 Spontaneous dissections occur more commonly in women, typically of child-bearing age or in the peripartum period, due to increased relaxins and other hemodynamic and biochemical alterations.3 The other broad categories of spontaneous dissection are those associated with atherosclerotic disease and the so-called idiopathic case.4 The LAD is involved in up to 75% of reported cases.5 Associated medical conditions that appear to predispose patients to spontaneous dissection include hypertension, coronary spasm, fibromuscular dysplasia and inflammatory and connective tissue diseases such as systemic lupus erythematosis and the antiphopholipid syndrome.6–10 In the pre-stent era, the NHLBI (National Heart, Lung and Blood Institute) developed a classification system for coronary artery dissections from A–F in increasing severity (Table 1). Their management thus varies depending on the severity of the dissection. Types A and B may be managed conservatively if they remain angiographically stable for 5–10 minutes.11 Types C–F should ideally be treated with stenting. It is critical for the angiographer to identify a dissection when present and recognize those factors described previously that may predispose a patient to this problem. Once identified, a careful attempt to wire the true lumen with the use of a soft-tip medium body, nonhydrophilic wire is reasonable. Verification of wire placement in the true lumen can be confirmed by injecting a small quantity of contrast through a 1.5 mm balloon to opacify the distal vessel and branches. If, however, the wire is in the false lumen, it should ideally be left in place and a second wire advanced. The first wire may act to deflect the second wire into the true lumen. Intravascular ultrasound may be considered as an adjunctive diagnostic modality to identify the distal extent of the dissection prior to stenting. After successful wiring of the true lumen, we suggest stenting distal-to-proximal to prevent further propagation of the dissection downstream. The choice of stent type should be based on the risk of restenosis considering the dissection length, vessel size and presence of diabetes. In this case, we chose to use drug-eluting stents given the length of the dissection to reduce restenosis long term.12,13 Neurofibromatosis is a genetic condition with an autosomal dominant mode of inheritance and an incidence of 1 in 3,000 live births. Among the several subtypes, Types I and II are the best defined. The vascular system is involvement mainly in NF-I, the subtype resulted from a mutation on the long arm of the chromosome.17 The clinical manifestations of NF-I are diverse including, but not limited to, café-au-lait spots, Lisch nodules, kyphoscoliosis, tibial pseudoarthrosis and increases in neoplasias such as acoustic neuromas, meningiomas, neurofibrosarcomas, and malignant schwannomas. Vascular involvement can occur in vessels of all calibers. Cases in the literature have mainly involved dissection and rupture of medium- and large-sized arteries.14,15 The mechanism of vasculopathy in neurofibromatosis remains unknown. Vascular injury is thought to occur either by invasion and weakening of the arterial wall by neuromatous tissue or via proliferation of spindle cells originating from smooth muscles.16,17 The most common reported vascular manifestation is aneurysmal dissection and/or rupture. The renal artery is the most commonly affected vessel and usually manifests clinically as renovascular hypertension.18 To our knowledge, this is the first reported case of a spontaneous coronary artery dissection in a patient with neurofibromatosis Type I. The recognition that vasculopathy in NF-I might involve the coronary tree should heighten the awareness of the potential risk of spontaneous dissection and therefore the rapid institution of definitive therapy. ______________________________ From Baystate Medical Center, Springfield, Massachusetts. Disclosures: Dr. Giugliano discloses the following relationships: member of the speakers bureau for Abbott, Cordis Corp., CardioVascular Therapeutics, Merck, Pfizer, Radi, Schering Pharmaceuticals, and The Medicines Company; is a consultant for Cordis, Medtronic, Gerson Lehrman Group, and The Medicines Company; has received research/grant support from AstraZeneca, Boston Scientific, CardioVascular Therapeutics, Cordis, Medtronic, Eli Lilly, Novartis and The Medicines Company. Dr. Sethi has no potential conflicts of interest to disclose. Manuscript submitted December 31, 2008, provisional acceptance given March 27, 2009, and final version accepted March 30. 2009. Address for correspondence: Gregory R. Giugliano, MD, SM, FACC, FSCAI, Baystate Medical Center, 759 Chestnut Street, Cardiology S4659, Springfield, MA 01199. E-mail: Gregory.giugliano@bhs.org

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