was drained. Two days after surgery, the thoracic drain could be removed. No complications occurred. Left arterial pulses were present. The patient was discharged symptom-free 7 days after admittance and is doing well 5 months after surgery. Comment Three similar cases have been published describing a timely relation between the ingestion of a PDE-5 inhibitor and the occurrence of an acute aortic dissection [1–3]. In all three, the dissection occurred in the critical time interval between the peak plasma concentration time (30 –120 minutes) and half-life (3–5 hours) of sildenafil. Because no patient had a history of any triggering factor (eg, mechanical stress, trauma), sildenafil was considered the instigating factor of the dissection. However, all three reported cases and our case had at least one wellestablished predisposing factor such as hypertension, cocaine abuse, and bicuspid aortic valve with ascending aortic aneurysm. As in the other cases, chemical analysis of the remaining half of the tablet was not performed; the same holds true for determining the serum levels of sildenafil and, in our case, tadalafil. In humans, sildenafil decreases aortic stiffness. The local production of nitric oxide (NO) by the aortic endothelium regulates vascular tone through stimulation of soluble guanylyl cyclase, resulting in cyclic guanosine monophosphate (cGMP) synthesis. It has been demonstrated that basal activity of soluble guanylyl cyclase (probably driven by NO) in aortic smooth muscle produces cGMP concentrations sufficient to induce strong vasorelaxation when PDE-5– dependent cGMP breakdown is reduced [4]. These findings corroborate previous reports in which vascular relaxation mediated by PDE-5 inhibitors (eg, sildenafil) was found to be related to the NO/cGMP signaling pathway in the rat aorta. Possibly, the effect of PDE-5 inhibitors differs between the layers of the aortic wall, thus favoring an intimal tear. In contrast to our patient, the other three used sildenafil for months before the aortic dissection occurred. Although sildenafil has an antiproliferative effect on vascular smooth muscle cells in the pulmonary circulation, it is possible to speculate that chronic, intermittent use of a PDE-5 inhibitor also induces changes in the aortic wall that ultimately can lead to dissection [5]. It is possible that similar effects on the aorta lead to noninflammatory smooth muscle cell loss in the aortic media, rendering it more vulnerable to dissection. Epidemiologic data on acute aortic dissection are scarce. An incidence of 3.5 per 100,000 person-years (95% confidence interval, 2.4 – 4.6) has been estimated. A correlation between vigorous sexual exercise and aortic dissection has been postulated in literature [6]. The dissection during sexual activities will be related to the increase of blood pressure during vigorous exercise. In a rat model, the central aortic pressure increases up to 19% during exercise [7]. Furthermore, it has been shown in an animal aortic aneurysm model that exercise leads to a more turbulent flow within the aorta, and this in turn © 2012 by The Society of Thoracic Surgeons Published by Elsevier Inc CASE REPORT SUN AND ROSS POSTERIOR FOSSA MENINGIOMA DURING CPB 653 increases shear pressures on its wall [8]. Undoubtedly, our case and the three other cases described in literature were subject to multifactorial commencement including predisposing factors, sexual activity, and the use of a PDE-5-inhibitor. Four case reports add another dimension to the various predisposing factors of acute aortic dissection. If a clinician is considering the prescription of a PDE-5 inhibitor in patients with predisposing factors of aortic dissection, the exclusion of aortic abnormalities is indicated. However, until more evidence is available, the precise role of PDE-5 inhibitors in the causation of aortic dissection remains speculative. References 1. Famularo G, Polchi S, Di Bona G, Manzara C. Acute aortic dissection after cocaine and sildenafil abuse. J Emerg Med 2001;21:78 –9. 2. Nachtnebel A, Stöllberger C, Ehrlich M, Finsterer J. Aortic dissection after sildenafil-induced erection. South Med J 2006;99:1151–2. 3. Tiryakioglu SK, Tiryakioglu O, Turan T, Kumbay E. Aortic dissection due to sildenafil abuse. Interact Cardiovasc Thorac Surg 2009;9:141–3. 4. Teixeira CE, Priviero FB, Webb RC. Differential effects of the phosphodiesterase type 5 inhibitors sildenafil, vardenafil, and tadalafil in rat aorta. J Pharmacol Exp Ther 2006;316:654 – 61. 5. Tantini B, Manes A, Fiumana E, Pignatti C, Guarnieri C, Zannoli R, et al. Antiproliferative effect of sildenafil on human pulmonary artery smooth muscle cells. Basic Res Cardiol 2005;100:131– 8. 6. Morris-Stiff G, Coxon M, Ball E, Lewis MH. Post coital aortic dissection: a case report. J Med Case Reports 2008;16:2– 6. 7. Niederhoffer N, Kieffer P, Desplanches D, LartaudIdjouadiene I, Sornay MH, Atkinson J. Physical exercise, aortic blood pressure, and aortic wall elasticity and composition in rats. Hypertension 2000;35:919 –24. 8. Khanafer KM, Bull JL, Upchurch GR Jr, Berguer R. Turbulence significantly increases pressure and fluid shear stress in an aortic aneurysm model under resting and exercise flow conditions. Ann Vasc Surg 2007;21:67–74. Fatal Hemorrhagic Infarction of Posterior Fossa Meningioma During Cardiopulmonary Bypass Hai Sun, MD, PhD, and Donald A. Ross, MD Department of Neurological Surgery, Oregon Health & Science University and Portland Veterans Medical Center, Portland, Oregon Few publications address cardiac surgery in the presence of meningioma. Individual complications include transient visual loss from a suprasellar meningioma, hemiparesis after mitral valve replacement with recovery after resection, and non-fatal hemorrhage into a posterior fossa meningioma. The largest report of 16 patients with Accepted for publication June 30, 2011. Address correspondence to Dr Ross, Department of Neurological Surgery, Oregon Health & Science University, 3303 SW Bond Ave, CH8N, Portland, OR 97239; e-mail: rossdo@ohsu.edu. 0003-4975/$36.00 doi:10.1016/j.athoracsur.2011.06.097 FEATURE ARTICLES Ann Thorac Surg 2012;93:653– 6 654 CASE REPORT SUN AND ROSS POSTERIOR FOSSA MENINGIOMA DURING CPB Ann Thorac Surg 2012;93:653– 6 known meningiomas over 11 years suggested a benign course, with no new neurologic symptoms and no required resection of a meningioma over an average follow-up of 31 months. In 2 cases we report a presumed posterior fossa meningioma led to fatal outcome after cardiac surgery performed on bypass. Possible causes and future considerations are discussed. (Ann Thorac Surg 2012;93:653– 6) © 2012 by The Society of Thoracic Surgeons A symptomatic meningiomas are commonly discovered in the era of magnetic resonance (MR) imaging. The elderly are especially likely to harbor undetected meningiomas. Many such incidental meningiomas are followed without intervention. The finding of an incidental meningioma has been reported in 0.28% of people in their sixth decade and 1.6% of people in their seventh decade of life. We report 2 patients with asymptomatic petrous face meningiomas, one known about and one not previously detected, who experienced fatal hemorrhagic infarction of the tumor after an otherwise uncomplicated cardiac surgery done on cardiopulmonary bypass. Case Reports Patient 1 FEATURE ARTICLES An 84-year-old man who could not undergo magnetic resonance imaging because of retained shrapnel was known to have at least two meningiomas. He had undergone resection of a large right occipital World Health Organization grade I meningioma 2 years earlier at another institution. A second tumor on the left petrous face and tentorial incisura was deemed high risk for resection and was under observation. A computed tomography (CT) scan in January 2011 did not show any interval enlargement of the tumor (Fig 1). He underwent coronary artery bypass grafting and aortic valve replacement with a porcine valve 3 months after the head CT scan. His blood pressure was extremely labile during and immediately after the operation. During the procedure, he was anticoagulated with a heparin infusion and his activated coagulation time (ACT) level was monitored and maintained in the target range. His ACT during the coronary artery bypass grafting and valve replacement portion of the surgery was 629, which was within the target range for the procedure. His anticoagulation was reversed at the end of the procedure with protamine (ACT 150, which was also within the target range), but he continued to bleed clinically at the surgical site. An additional 60 mg of protamine was administered despite a normal ACT. He continued to bleed after surgery and was further transfused with packed red blood cells, fresh frozen plasma, cryoprecipitate, and platelets. He initially awoke from the procedure and was at his neurologic baseline for 2 days, but then become progressively somnolent. Examination showed no response to voice or command and weak withdrawal of the lower but not the upper extremities consistent with a cruciate paralysis. A CT scan revealed a large left petrous face low attenuation Fig 1. Axial, unenhanced computed tomography scan taken 3 months before cardiac surgery showing a large, left petrous face mass with mild mass effect on the fourth ventricle, reportedly unchanged from a scan from 2 years earlier. mass with adjacent hemorrhage and edema with marked compression and distortion of the brainstem and incipient hydrocephalus (Fig 2). A ventriculostomy was placed and drained at 15 cm above the tragus. He remained deeply comatose. When he did not improve after 5 days of aggressive support, support was withdrawn and he immediately died. Patient 2 A 72-year-old woman with no previous history of headaches or neurological complaints underwent coronary bypass grafting for atherosclerotic occlusive disease. The procedure was uncomplicated. She was kept intubated and sedated the night of her surgery. The next morning, the sedation was discontinued in preparation for extubation. The patient, however, did not awaken. She was given additional time to emerge from the sedation. When she was still not awake 2 days postoperatively, a noncontrast head CT was obtained. This showed massive obstructive hydrocephalus secondary to a large, low attenuation, sessile mass arising from the left petrous face and consistent with a meningioma. A ventriculostomy was placed and cerebrospinal fluid drained at 10 cm above the tragus. After a week of drainage, she had not improved and remained deeply comatose. After consultation with the family, support was withdrawn and she died. Comment There are few publications addressing cardiac surgery in the presence of a meningioma [1– 6]. Individual case Fig 2. Axial, unenhanced computed tomography scan revealed a large left petrous face low attenuation mass with adjacent hemorrhage and edema with marked compression and distortion of the brainstem and incipient hydrocephalus. complications reported include transient visual loss from a suprasellar meningioma [5], hemiparesis 2 days after mitral valve replacement requiring resection of a parasagittal meningioma with recovery of neurologic function [3], and hemorrhage into a posterior fossa meningioma [4]. The last, while somewhat similar to our cases, responded to nonoperative management and was later treated with radiosurgery. The largest group of patients reported is 16 patients with a known preoperative diagnosis of meningioma, accumulated over an 11-year period and studied retrospectively [1]. Nine tumors were falcine, four convexity, and three cerebellopontine angle in location. Only 1 patient received perioperative dexamethasone at the recommendation of a neurosurgical consultant. No patient reported any new neurologic symptoms related to their meningioma and none required resection of their meningioma over an average follow-up period of 31 months. In the two cases we report here, the presence of a presumed posterior fossa meningioma led to fatal outcome after cardiac surgery performed on bypass. The patient in the first case suffered hemodynamic instability and postprocedural bleeding diathesis requiring aggressive reversal of anticoagulation, while there were no apparent intraoperative and perioperative adverse events during the second case. Possible causes of tumor CASE REPORT SUN AND ROSS POSTERIOR FOSSA MENINGIOMA DURING CPB 655 swelling and infarction may include relative hypotension while on bypass resulting in poor perfusion to the tumor, decreased plasma osmolality with a resulting increase in peritumoral brain edema, a hypercoagulable state after reversal of anticoagulation at the end of the procedure, and increased blood brain barrier permeability during cardiopulmonary bypass [7]. Meningiomas are often quite vascular and may therefore undergo therapeutic embolization before resection. After successful embolization, tumors are known to swell from cytotoxic edema and other processes related to necrosis, including upregulation of some vascular endothelial growth factor RNA isoforms [8]. Meningioma resective surgery is therefore usually scheduled to follow shortly after embolization so that the edema does not become symptomatic. Some authors have recommended mild hypocapnea, perioperative dexamethasone administration, and use of hypertonic saline during cardiac surgery in patients with known meningiomas [2], but it is speculative as to whether any of these interventions would have altered our patients’ outcomes. Some have undertaken off pump coronary artery bypass grafting to avoid complications with a known tumor, but not all cardiac surgeries can be performed off bypass [6]. It is difficult to make recommendations about future similar cases. The unfortunate outcome of the two cases reported here certainly highlights the risk associated with patients with posterior fossa meningioma undergoing cardiac surgery on bypass. It would not, however, be cost-effective to recommend cranial imaging on every patient undergoing cardiopulmonary bypass as meningiomas are common in older patients. Even if every posterior fossa mass were detected preoperatively, not all such tumors can be resected with acceptable neurologic morbidity and many patients scheduled for cardiac surgery are elderly or have significant medical comorbidities and, therefore, may not be candidates for resection of these tumors before repair of their cardiac pathology. Consideration should be given to off bypass surgery where feasible, the use of perioperative steroids, maintenance of high normal serum osmolality, adequate cerebral perfusion, careful reversal of anticoagulants, and avoidance of intraoperative and perioperative hemodynamic instability. Noninvasive intraoperative monitoring of central nervous system function with motor evoked potentials, somatosensory evoked potentials, or electroencephalography might be useful in patients with known intracranial masses, but would not be cost-effective for use in all cardiac surgery cases. Early postoperative brain imaging of patients not awakening promptly from cardiac anesthesia and of patients with known intracranial masses could be recommended, as early discovery of complications such as cerebellar hemorrhage and acute hydrocephalus is crucial since there may be only a brief window of time during which the patient might be salvaged. Immediate detection of a symptomatic posterior fossa mass could lead to life saving ventriculostomy or posterior fossa decompression. FEATURE ARTICLES Ann Thorac Surg 2012;93:653– 6 656 CASE REPORT AVLONITIS ET AL SHUNT OCCLUSION AFTER CLOPIDOGREL CESSATION The authors thank Shirley McCartney, PhD, for editorial assistance and Andy Rekito, MS, for illustrative assistance. References 1. Aleksic I, Sommer SP, Kottenberg-Assenmacher E, et al. Cardiac operations in the presence of meningioma. Ann Thorac Surg 2009;88:1264 – 8. 2. Grigore AM, Grocott HP, Newman MF. Anesthetic management of a patient with a brain tumor for cardiac surgery. J Cardiothorac Vasc Anesth 2000;14:702– 4. 3. Kurisu K, Hisahara M, Ando Y, Tominaga R. An unusual manifestation of brain tumor: development of delayed hemiplegia after cardiopulmonary bypass. J Card Surg 2007;22: 417– 8. 4. Maeda K, Gotoh H, Chikui E, Furusawa T. Intratumoral hemorrhage from a posterior fossa tumor after cardiac valve surgery– case report. Neurol Med Chir (Tokyo) 2001;41:548 –50. 5. Slavin ML. Acute remitting visual loss after coronary artery bypass surgery caused by a suprasellar meningioma. Am J Ophthalmol 1987;104:434 –5. 6. Tashiro T, Zaitu R, Nakamura K, et al. Off-pump CABG for a patient with a brain tumor. Ann Thorac Cardiovasc Surg 2000;6:193–5. 7. Harris DN, Oatridge A, Dob D, Smith PL, Taylor KM, Bydder GM. Cerebral swelling after normothermic cardiopulmonary bypass. Anesthesiology 1998;88:340 –5. 8. Ellis JA, D’Amico R, Sisti MB, et al. Pre-operative intracranial meningioma embolization. Expert Rev Neurother 2011;11: 545–56. FEATURE ARTICLES Occlusion of Modified BlalockTaussig Shunt After Clopidogrel Cessation Vassilios Spiridon Avlonitis, MD, PhD, Silvia Planas, MD, Alison M. Hayes, MBBS, FRCP, and Andrew Parry, FRCS (CTh) Bristol Heart Institute, and Histopathology Department, Bristol Royal Infirmary, Bristol; and Bristol Royal Hospital for Sick Children, Bristol, United Kingdom It has been suggested previously that rebound hypercoagulability may be responsible for morbidity and mortality following clopidogrel cessation in adults with acute coronary syndrome. We report a case of acute occlusion of a modified Blalock-Taussig shunt in an infant after clopidogrel discontinuation. (Ann Thorac Surg 2012;93:656 – 8) © 2012 by The Society of Thoracic Surgeons A cute occlusion of a modified Blalock-Taussig shunt (MBTS) is a potentially catastrophic complication. A recent study showed that patients treated with clopidogrel after acute coronary syndrome are at high risk of acute myocardial infarction and death early after discontinuation of the drug [1]. This finding suggested a possi- Accepted for publication July 26, 2011. Address correspondence to Dr Avlonitis, Bristol Heart Institute, Bristol Royal Infirmary, Upper Maudlin St, Bristol, BS2 8HW, United Kingdom; e-mail: avlonitis@hotmail.com. © 2012 by The Society of Thoracic Surgeons Published by Elsevier Inc Ann Thorac Surg 2012;93:656 – 8 ble rebound effect associated with abrupt clopidogrel cessation. We report a case of acute thrombosis of a MBTS following clopidogrel discontinuation. A male child was born at 40 weeks’ gestation with an antenatal diagnosis of tricuspid and pulmonary atresia and ventricular septal defect. At birth, echocardiography showed several major aortopulmonary collateral arteries (MAPCAs), atrial septal defect, tricuspid atresia, two ventricular septal defects, small right ventricle, pulmonary atresia, and right aortic arch. At 5 days of age, he underwent cardiac catheterization, and at 7 weeks of age he underwent unifocalization of all MAPCAs with augmentation of the central portion using autologous pericardium. A MBTS was performed between the left subclavian artery and the unifocalized arteries using a 3.5-mm polytetrafluoroethylene graft. The operation and postoperative recovery were uneventful, and the patient was discharged 9 days later, receiving aspirin (5 mg/kg) and clopidogrel (0.2 mg/kg). Oxygen saturations at discharge were 75%. At follow-up, at age 20 weeks, the child exhibited dyspnea with oxygen saturations between 70% and 75%. Echocardiography showed reduced flow in the left pulmonary artery, and cardiac catheterization confirmed stenosis of the left MAPCA as it passed over the left bronchus. The decision was made to perform an additional left MBTS to the left neopulmonary artery. The clopidogrel was discontinued in preparation for surgery, but the operation had to be postponed because the child developed viral conjunctivitis. Aspirin treatment was restarted, but clopidogrel was not because of the imminent surgery. The child was taken to surgery 7 days later with an oxygen saturation of 75%. After performing a left thoracotomy, he became increasingly cyanotic and the oxygen saturation fell dramatically, leading to bradycardia. The diagnosis of occlusion of the previous MBTS was made. The child was immediately positioned supine, cardiopulmonary resuscitation was performed, and cardiopulmonary bypass was established through cannulation of the left femoral vessels. A repeated sternotomy was performed. The previous shunt was excised and found to be occluded with a white granular clot. A new 3.5-mm central shunt was constructed between the left side of the ascending aorta and the branch pulmonary arteries. Cardiopulmonary bypass was discontinued on low-dose inotropic support, protamine was administered, the femoral vessels were repaired, and the chest was closed. The patient was transferred to the intensive care unit. During the first 24 hours, he had episodes of desaturation. Because of the preceding arrest, there were concerns regarding neurologic status. Electroencephalography showed nonconvulsive status epilepticus, which was treated with phenytoin. On the fifth postoperative day, the patient developed anisocoria. Magnetic resonance imaging of the brain showed diffuse edema and changes consistent with severe diffuse ischemic damage. The child deteriorated and died on the 12th postoperative 0003-4975/$36.00 doi:10.1016/j.athoracsur.2011.07.071