Ann Thorac Surg 2006;81:2296-2298
© 2006 The Society of Thoracic Surgeons
Case report
Management of Type A Aortic Dissection and a Large Pheochromocytoma: A Surgical Dilemma
Frank W. Bowen, MD
a
,
*
,
Jessie Civan, BS
a
,
Anton Orlin, BS
a
,
Thomas Gleason, MD
b
a Division of Cardiothoracic Surgery, Department of Surgery, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
b Northwestern Memorial Cardiovascular Institute, Division of Cardiothoracic Surgery, Northwestern University School of Medicine, Chicago, Illinois
Accepted for publication August 12, 2005.
* Address correspondence to Dr Bowen, Department of Cardiothoracic Surgery, 6th Floor Silverstein Pavilion, Hospital of the University of Pennsylvania, 34th and Spruce Streets, Philadelphia, PA 19103 (Email: bowenf{at}uphs.upenn.edu).
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Abstract
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The concomitant presence of an undiagnosed pheochromocytoma at the time of an acute type A aortic dissection creates a difficult management dilemma. The case of a patient with an acute type A aortic dissection and pheochromocytoma was stabilized with catecholamine blockade before undergoing ascending aortic and total arch replacement. Fourteen days later the patient underwent resection of the pheochromocytoma. Temporizing medical stabilization of the pheochromocytoma with catecholamine blockade for a period of 5 days allowed for safe aortic reconstruction and seems to be prudent, provided that the aortic dissection remains relatively stable.
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Introduction
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Triplett and Atuk [1] reported the first case of a patient with dissecting aortic aneurysm and pheochromocytoma in 1975. More recently, Azizi and colleagues [2] reported a case of concomitant type A dissection and pheochromocytoma. There have been other reports of pheochromocytoma associated with dissecting abdominal aortic aneurysm and carotid artery dissection.
Type A aortic dissection is a surgical emergency with increasing mortality as time elapses between diagnosis and surgical intervention. Initial management of type A aortic dissection always includes strict blood pressure stabilization with intravenous antihypertensive medications, but in the presence of a catecholamine-secreting pheochromocytoma, control can be extremely difficult. Moreover, surgical manipulation of a pheochromocytoma may trigger an intractable hypertensive crisis and lead to aortic disruption [3]. Both lesions present life-threatening situations that pose a major management dilemma. The following case illustrates an integrated approach to the management of a concomitant type A dissection and pheochromocytoma that facilitated safe aortic arch replacement.
The patient is a 49-year-old man that presented with the acute onset of atrial fibrillation to an outside institution. After several unsuccessful attempts at pharmacologic and electrical cardioversion, he was admitted for catheter-based radiofrequency ablation by the cardiologist. During recovery from the ablation in the electrophysiology lab, the patient had chest pain develop, and emergent cardiac catheterization suggested the presence of type A aortic dissection. The patient was started on intravenous labetalol to titrate systolic blood pressure to less than 100 mm Hg and heart rate to less than 70. He also underwent computed tomographic angiography of the chest and abdomen. This confirmed the diagnosis of type A dissection with intramural hematoma (Fig 1) and also incidentally revealed a 6.7 cm x 9.2 cm hypervascular retroperitoneal mass anterior to the inferior vena cava (Fig 2). The mass extended from the first portion of the duodenum to below the aortic bifurcation. The patient was transferred to our institution. Differential diagnosis at that time included extra-adrenal pheochromocytoma, germ cell tumor, or retroperitoneal sarcoma. Appropriate diagnostic tests for pheochromocytoma including serum and urinary catecholamine were sent at that time, but the results were not available for 48 hours. At presentation the patient was hemodynamically stable and demonstrated no evidence of aortic rupture or malperfusion syndrome. Initially he was taken to the operating room for emergent repair of the aortic dissection. During induction of anesthesia the patient had a hypertensive crisis develop with a systolic pressure of greater than 250 mm Hg that ultimately responded to intravenous phentolamine, and the procedure was aborted because the diagnosis of pheochromocytoma was suspected. While awaiting return of diagnostic laboratory studies, the patient was started on phenoxybenzamine (20 mg po twice a day) and metoprolol (25 mg po 4 times a day). Doses were titrated to achieve a systolic blood pressure of less than 100, and heart rate of less than 70. The diagnosis of pheochromocytoma was subsequently confirmed by elevated serum levels of norepinephrine (14,000 pg/mL [normal < 410 pg/mol]) and epinephrine (59 pg/mL [normal < 5 pg/mol]), as well as elevated urine levels of vanillylmandelic acid (102 mg/day [normal < 10 mg/day]), metanephrines (403 mg/day [normal < 1.3 mg/day]), and normetanephrines (51,646 mg/day [normal < 0.9 mg/day]).
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Fig 1. Computed tomographic angiography demonstrating intramural hematoma and dissection flap (arrow) in the ascending aorta indicating type A dissection.
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Fig 2. Computed tomographic angiography demonstrating 6.7 cm x 9.2 cm hypervascular mass (arrow), which was later confirmed to be extra-adrenal pheochromocytoma.
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Now our objective was to achieve adequate catecholamine blockade (heart rate of 50 to 60 and systolic blood pressure <110) to prevent another intraoperative hypertensive crisis upon induction of anesthesia prior to attempting repair of the type A dissection again. After consultation with our endocrinologist and endocrine surgeon it was agreed that 5 days of phenoxybenzamine and metoprolol represented the minimum amount of time required for satisfactory blockade. Recognizing the volatility of the type A dissection, the patient was serially scanned with a computed tomographic angiography every 36 to 48 hours during this period to ensure that the aortic dissection was stable. He was closely monitored in the intensive care unit. After 5 days of catecholamine blockade, the ascending aortic and total aortic arch replacement was completed with a circumferential dissection of the entire arch and the proximal innominate and left common carotid arteries. Cerebral protection was maintained with deep hypothermic circulatory arrest using antegrade cerebral perfusion through the right axillary artery and direct ostial left carotid cannulation using retrograde cerebral perfusion for final removal of air. Anesthetic induction was uneventful. After recovery, alpha blockade and beta blockade were continued, and 14 days later he underwent resection of the pheochromocytoma through a midline laparotomy. He recovered uneventfully, and 12 months after repair he is doing well.
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Comment
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We could identify only a single case in the literature detailing the concomitant presence of pheochromocytoma and acute type A aortic dissection [2]. Pheochromocytoma is a rare neoplasm that occurs in less than 0.2% of hypertensive patients. In at least 10% of patients the tumor is incidentally discovered during computed tomography or magnetic resonance imaging of the abdomen for unrelated symptoms. Elevated serum levels of epinephrine, norepinephrine, and dopamine are characteristic and are diagnostic in 95% of symptomatic patients. As much as 15% of pheochromocytomas are extra-adrenal [4]. The diagnostic studies of choice are for urinary catecholamines, metanephrine, and vanillylmandelic acid, and serum assays of norepinephrine, epinephrine, or fractionated metanephrines. These studies are usually available only in specialty laboratories and may take as many as 48 hours to confirm. Rapid testing assays are not generally available.
In a patient who has a pheochromocytoma, an acute hypertensive crisis may develop at the induction of anesthesia or intraoperatively, and this can be lethal. Manipulation of a pheochromocytoma can precipitate the release of massive amounts of catecholamines. In one study, 36 of 143 patients undergoing pheochromocytoma resection had sustained intraoperative hypertension develop [3].
To avoid hypertensive crisis at the induction of anesthesia complete alpha blockade and beta blockade are necessary. A 10-day to 14-day course of catecholamine blockade is optimal. Alternatively, metyrosine (a tyrosine hydroxylase inhibitor that blocks the synthesis of norepinephrine) is very effective but typically takes as much as 3 weeks to eliminate all norepinephrine synthesis [5].
Alternatively the hospital mortality rate of medically managed type A dissection and intramural hematoma is 55% to 58% compared with 8% to 26% for surgically managed patients [6–8], a fact that indicates the emergent need for operative repair. However, the presence of concomitant pheochromocytoma, as in this case, may preclude safe anesthetic induction and operative repair. An attempt at brief medical stabilization seems prudent to allow for acceptable catecholamine blockade as long as there is continued radiologic surveillance of the dissection process and careful interim patient monitoring. Cross-sectional imaging (computed tomographic angiography or magnetic resonance angiography) should be obtained at frequent intervals (24 to 48 hours) during this period of intensive care unit-monitored catecholamine blockade. If a change in the stability of the patient occurs, or if the extent and character of the dissection dramatically changes on computed tomographic angiography or magnetic resonance imaging, it should raise concern for impending rupture, myocardial infarction, stroke, or malperfusion. Then immediate operative intervention with adequate availability of an alpha-blocking agent (phentolamine 5 to 20 mg intravenously/dose, repeated as necessary) is recommended. Concomitant (single-stage) resection of the pheochromocytoma was entertained in this case; however, it was determined that resection of the tumor itself would still be safer after more complete alpha blockade and beta blockade (10 to 14 days). Collaboration with our endocrinology and endocrine surgical colleagues facilitated this decision for a truncated (5-day) course of catecholamine blockade prior to aortic reconstruction, collectively weighing the pros and cons of immediate, unblocked versus delayed, catecholamine blocked-surgical intervention. We recommend compiling a multidisciplinary management team that includes the cardiothoracic surgeons, anesthesiologist, endocrine surgeon, endocrinologist, and radiologist to orchestrate the care of this conundrum and potentiate safe and successful aortic reconstruction and tumor resection.
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References
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- Triplett JC, Atuk NO. Dissecting aortic aneurysm associated with pheochromocytoma South Med J 1975;68(6):748-753.[Medline]
- Azizi M, Fumeron C, Jebara V, Day M, Fagon JY, Plouin PF. Pheochromocytoma revealed by type A acute aortic dissection J Hum Hypertens 1994;8(1):69-70.[Medline]
- Kinney MA, Warner ME, vanHeerden JA, et al. Perianesthetic risks and outcomes of pheochromocytoma and paraganglioma resection Anesth Analg 2000;91(5):1118-1123.[Abstract/Free Full Text]
- Pacak K, Linehan WM, Eisenhofer G, Walther MM, Goldstein DS. Recent advances in genetics, diagnosis, localization, and treatment of pheochromocytoma Ann Intern Med 2001;134(4):315-329.[Abstract/Free Full Text]
- Roman S. Pheochromocytoma and functional paraganglioma Curr Opin Oncol 2004;16(1):8-12.[Medline]
- Hagan PG, Nienaber CA, Isselbacher EM. The International Registry of Acute Aortic Dissection (IRAD)new insights into an old disease. JAMA 2000;283(7):897-903.[Abstract/Free Full Text]
- Bavaria JE, Brinster DR, Gorman RC, Woo YJ, Gleason T, Pochettino A. Advances in the treatment of acute type A dissectionan integrated approach. Ann Thorac Surg 2002;74(5):S1848-S1852; discussion S1857-63.[Abstract/Free Full Text]
- von Kodolitsch Y, Csosz SK, Koschyk DH. Intramural hematoma of the aortapredictors of progression to dissection and rupture. Circulation 2003;107(8):1158-1163.[Abstract/Free Full Text]
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Abstract
Introduction
