Hypertension and tachyarrhythmias during an operation are rare presentations of an unsuspected pheochromocytoma. Cerebral events, acute myocardial infarction, and perioperative hemorrhagic complications are associated. A patient who developed severe hypertension during an elective combined coronary artery bypass grafting (CABG) and aortic valve replacement (AVR) is described.
A 60-year-old man with symptomatic severe aortic stenosis and single vessel coronary artery disease was presented. His comorbidities included diabetes mellitus on oral hypoglycemics, and hypertension treated with ACE inhibitor, calcium antagonist, and thiazide diuretic for 15 years. Duplex ultrasound performed for transient ischemic attack 10 years ago demonstrated only minor carotid artery disease. He was diagnosed with spontaneous left axillary vein thrombosis 1 year ago and had taken warfarin for 6 months.
Blood pressure recordings by his general practitioner in the preceding 5 years showed good control. The peak transvalvular gradient was 124 mm Hg, with an aortic valve area of 0.7 cm2. Moderate concentric left ventricular hypertrophy was present, with preserved systolic function (75% left ventricular ejection fraction). Preoperative serum biochemistry findings and hematology measurements were normal.
Institutional ethics committee approval and patient consent was obtained before the operation. Single vessel CABG and AVR using an investigational bioprosthesis (3f Enable; ATS Medical, Inc., Minneapolis, MN USA) was performed. His blood pressure was 97/58 mm Hg during routine anesthetic induction using fentanyl, thiopentone, and vecuronium. Inhalational anesthesia was maintained with isoflurane in an air and oxygen mixture before cardiopulmonary bypass (CPB). Anesthesia during CPB was maintained by an intravenous infusion of propofol 10%. During transesophageal echocardiography, his blood pressure rose to 271/112 mm Hg associated with sinus tachycardia of 104 beats per minute. Intravenous phentolamine (1.5 mg) and labetalol (5 mg) was administered in addition to nitroglycerin infusion. After satisfactory blood pressure control, we proceeded with the operation anticipating the need to treat his cardiac lesions regardless of the presence of an undiagnosed pheochromocytoma.
The left internal mammary artery was harvested after median sternotomy, and the patient was heparinized for routine CPB. The left-anterior descending coronary artery (LAD) was grafted using the aortic cross-clamp fibrillation technique. Then antegrade cold crystalloid cardioplegia was delivered through the coronary ostia to arrest the heart. After leaflet resection and annular decalcification, a size 23 of 3f Enable valve manufactured using a 3f Aortic bioprosthesis Model 1000 mounted on a self-expanding nitinol frame was implanted using a single-pledgeted “guiding-suture” at the annulus (Fig. 1).
The prosthesis implantation time was 10 minutes. Total aortic cross-clamp duration was 37 minutes (27 minutes for AVR) with 51 minutes on CPB. The patient was weaned off CPB uneventfully without the need for inotropes. A complete transesophageal echocardiography study showed mild paravalvular regurgitation, a peak transvalvular gradient of 15 mm Hg, and an effective orifice area of 2.6 cm2.
In the intensive care unit, he remained stable on small doses of intravenous nitroglycerin infusion. He made an uneventful recovery, and aspirin (75 mg) was recommenced for the next day. He was discharged from hospital on the sixth postoperative day, delayed only by investigations for raised plasma catecholamines.
The raised 24-hour urinary catecholamines (25.47 μmol normetanephrine [upper limit, 4.50 μmol] and 2.74 μmol metanephrine [upper limit, 1.90 μmol]) and plasma catecholamines (6368 pmol/L normetanephrine [reference range, 120–1180 pmol/L] and 60 pmol/L metanephrine [reference range, 80–510 pmol/L]) were subsequently localized to a right adrenal pheochromocytoma (Fig. 2A, B). Whole body 123I-metaiodobenzylguanidine (an iodinated norepinephrine analogue with uptake by catecholamine synthesizing tissue) nuclear scan excluded metastatic disease (Fig. 2C). He subsequently underwent successful laparoscopic adrenalectomy and remains well 11 months post-AVR.
Pheochromocytomas are tumors of chromaffin cells that produce and secrete catecholamine (mainly norepinephrine and epinephrine) but can secrete other substances such as calcitonin, somatostatin, and ACTH. Although the predominant manifestation of this condition is severe, sustained or paroxysmal hypertension and other cardiac symptoms such as arrhythmia, obstructive cardiomyopathy, and myocardial ischemia are well recognized. Vague symptoms (eg, constipation and polyuria) may be related to hypercalcemia, hyperreninemia, and hypokalemia. Suspected “paraneoplastic” prothrombotic tendency has been rarely described: (1) cerebral venous thrombosis1; (2) deep venous thrombosis2; and, in this patient, (3) spontaneous left axillary vein thrombosis.
Successful CABG both on and off-pump,3 mitral valve replacement,4 concurrent CABG with adrenalectomy,5 and even heart transplant6 have been described in patients with pheochromocytomas. We described a patient with an unanticipated pheochromocytoma undergoing combined AVR-CABG and postulate that the favorable outcome despite the hypertensive crisis was a result of (1) a high index of suspicion; (2) immediate aggressive treatment of the hypertension bearing in mind its pathophysiology, using phentolamine and labetalol; (3) expeditious surgery with short duration of aortic cross-clamping; and perhaps, (4) the quick implant time of a new sutureless prosthesis.
Optimal preparation of patients undergoing pheochromocytoma resection includes preoperative blood pressure control. Phenoxybenzamine (a nonselective irreversible α-adrenoceptor inhibitor) has been used for many years. The shorter-acting selective-α1 antagonists (eg, prazosin and doxazosin) cause less tachyarrhythmia and sedation, negating the need for concurrent β-blockade.7 β-blockade should not be started before α-blockade because the beneficial peripheral vasodilatory β2 effect is lost. In patients not receiving adrenergic inhibitors, improved operative mortality was related to the use of volume expansion for hypotension rather than noradrenaline.8
Phentolamine and labetalol7 (competitive peripheral α- and β-adrenoceptor antagonist) can be used for intraoperative hypertension. Labetalol is being preferred in cardiac patients because it reduces blood pressure, heart rate, and peripheral vascular resistance with minimal change in resting cardiac output or stroke volume. Volatile agents such as isoflurane can also rapidly decrease blood pressure. Tachyarrhythmia can be controlled with esmolol, and occasionally, lidocaine or amiodarone are needed.
We report a patient with occult pheochromocytoma presenting atypically with “paraneoplastic” axillary vein thrombosis. Intraoperative hypertensive crisis during CABG-AVR brought the diagnosis to fore. The coordinated effort of the anesthetist, perfusionist, and surgeon was crucial to the patient's good outcome.
The patient is part of a multicenter device approval study sponsored by ATS Medical, Minneapolis, MN USA.
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