Eur J Cardiothorac Surg 2003;24:712-715
© 2003 Elsevier Science NL
Interventions in heart and thyroid surgery: can they be safely combined?
Bassam Abbouda*,
Ghassan Sleilatyb,
Bechara Asmarb,
Victor Jebarab
a Department of General and Endocrine Surgery, Hotel Dieu deFrance Hospital, Faculty of Medicine, Saint-Joseph University, Alfred Naccache Street, Beirut, Lebanon
b Department of Thoracic and Cardiovascular Surgery, Hotel Dieu deFrance Hospital, Faculty of Medicine, Saint-Joseph University, 166830 Beirut, Lebanon
Received 9 May 2003;
received in revised form 18 June 2003;
accepted 18 June 2003.
* Corresponding author. Tel.: +961-1-615300; fax: +961-1-615295
e-mail: dbabboud{at}yahoo.fr
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Abstract
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Objective: Thyroid diseases are relatively common problems in patients with cardiac disease. The aim of this study was to evaluate the feasibility of combined interventions in heart and thyroid surgery. Methods: A retrospective study of 2530 cardiac operations yielded six patients who underwent thyroid intervention combined with cardiac surgery (coronary artery bypass grafting, valvular surgery or both) between 1996 and 2003. All patients were examined for age, gender, cardiac problems, thyroid pathology and related symptoms. Results: four males and two females were operated for coronary artery disease, valvular disease or both and for thyroid pathologies. All patients had anticoagulation with intravenous heparin peroperatively and then postoperatively. No patient suffered from bleeding at the neck neither per- or postoperatively. No hemodynamic or cardiovascular compromises were noted. Conclusion: The combined staged thyroid and cardiac surgery was feasible with a little risk for the both operations.
Key Words: Heart • Thyroid • Surgery
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1. Introduction
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Thyroid disease in patients with cardiac disease, either coronary or valvular, is a common finding, reaching 11% [1]. Its prevalence depends of the nature of thyroid disease, patients’ age, frequency of screening as well as concomitant cardiac medications that affect thyroid metabolism. Thyroid dysfunction affects cardiovascular physiology by different means, including myocardial inotropy, heart rate, cardiac output and peripheral arteries reactivity [2].
While anti-thyroid drugs and radioactive iodine are used to treat hyperthyroid diseases (e.g. Graves’ disease), thyroid surgery remains the mainstay treatment of these and other disorders of the thyroid gland. It is performed under general anesthesia. Thus, apart of risks of the act itself, general anesthesia carries out considerable risks for patients suffering from advanced coronary artery and/or valvular heart disease, mainly toxic crisis for unprepared hyperthyroid patients, and various serious manifestations in the hypothyroid patients.
Timing of thyroid surgery in candidates for major cardiovascular surgery, mainly coronary artery bypass grafting surgery (CABG) or valve surgery is still not answered. It would be prohibitive, in terms of cardiac risk, to propose thyroid surgery prior to cardiac surgery. On the other hand, performing thyroidectomy weeks or months after initial CABG/valvular surgery exposes patients to the cumulative risk of two independent interventions. Thus, managing both thyroid and cardiac problems in the same-staged operation seems rational and tempting [3,4].
The aim of this study was to evaluate the feasibility of combined interventions in heart and thyroid surgery.
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2. Patients and methods
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This retrospective study was designed to evaluate the risk of combined interventions in cardiac and thyroid. Between July 1996 and March 2003, six patients out of 2530 admitted at our institution and planned for elective cardiac surgery were suffering from thyroid disease amenable to surgery. All patients’ charts were reviewed for age, gender, cardiac pathology, thyroid pathology, type of surgery, pathology reports, and postoperative laboratory examinations.
Patients were admitted electively for cardiac surgery. Free thyroxine and thyrotropin levels were measured to assess thyroid function, and blood urea nitrogen and creatinine levels were measured to assess renal function. Fasting serum calcium and phosphorus were measured preoperatively and measurements were repeated immediately after operation. All patients with hyperthyroidism were treated with combination of methimazole and propranolol until free thyroxin and triiodothyronine levels were normalized.
In the operating room, patients were positioned as for coronary artery bypass surgery via median sternotomy with hyperextension of the neck. A Swan–Ganz catheter was inserted routinely for hemodynamic surveillance. Iodine-free solutions such chlorehexidine were used in swabbing the anterior neck region in order to avoid iodine absorption and subsequent perturbation of thyroid tests and function. Staff surgeons performed all operations. Thyroidectomy was performed via a transverse cervicotomy. During this first stage, patient was closely monitored for any hemodynamic disturbance and the cardiovascular team was ready for any abrupt incident. Hemostasis in the surgical field was meticulous. By the end of the intervention, the cardiovascular team began cardiac surgery using cardiopulmonary bypass via a classical sternotomy. The neck wound was left open during all the procedure, allowing monitoring any bleeding from operating site under the full heparinization (3 mg/kg) that accompanied cardiopulmonary bypass. At the end of the CABG surgery and following administration of adequate protamine dose in order to reverse heparinization, the neck wound was closed without drains.
All patients were admitted postoperatively in the cardiovascular surgical unit. Thyroid function tests, calcium and phosphorus serum levels were added to the routine blood tests. Patients were followed by serial hemodynamic measurements via the Swan–Ganz catheter. Levothyroxine therapy was begun on the day following surgery. Anticoagulants were prescribed as usual: heparin was began 12 h postoperatively; for CABG surgery, low-dose aspirin was initiated at day 1; oral anticoagulants were prescribed at day 1 also for valve surgery patients. Monitoring of the cervical wound was assessed closely for the first postoperative day than twice daily for the remaining period of hospitalization.
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3. Results
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The six patients (two women and four men) who underwent thyroidectomy with combined cardiac surgery during the study period were included. Patients’ ages ranged from 42 to 77 years, with an average age of 59.3 years.
Etiologies of thyroid disorder as well as patients characteristics are summarized in Table 1: four patients were hyperthyroid, and two were eutyhroid with a substernal goiter. No patients had previous thyroid operation. Related symptoms were: dyspnea, dysphagia, nervousness, palpitations, tachycardia, asthenia and weight loss.
Thyroid disease was present for a mean duration of 24 years (range 2–40 years). Thyroid disease history preceded cardiac disease in four cases (Cases 2, 3, 5 and 6), while it appeared after coronary heart disease in the case 1. A direct relation between amiodarone administration and thyroid disease was ascertained in this latter case (Case 1). Patients 1, 3, 5 and 6 had pretreatment with tapazole to control hyperthyroidism prior to surgical intervention.
Individual thyroid function tests along with neck imaging characteristics and modalities of surgery are shown in Table 2: values of thyroid-stimulating hormone (TSH) ultrasonography, free tetra-iodothyronine (FT4) and tri-iodothyronine (T3) varied from 0.001 to 2.7 mIU/l, 1.2 to 5.4 ng/dl, and 0.87 to 1.3 ng/ml, respectively. Calcium and phosphorous values varied from 2.2 to 2.43 and 0.93 to 1.2, respectively. Imaging studies included chest X ray (n=6), cervicomediastinal computed tomography (CT) scan (n=2), thyroid scintigraphy with technetium (n=4).
Mean operative cervical surgery time was 65±10 min. Thyroidectomy was possible in all cases. A standard thyroid lobectomy and isthmusectomy was performed in two patients, and a bilateral thyroid resection was completed in four patients. Cardiac interventions immediately succeeded neck surgery. Types of cardiac interventions are shown in Table 3. Cardiac interventions in these patients were: Mitral valve replacement (n=2), aortic valve replacement (n=2), coronary artery bypass surgery with aortic valve replacement (n=1), and coronary artery bypass surgery with aortic and mitral valve replacement (n=1).
Pathology findings are listed in Table 1: Toxic multinodular goiter (n=4), and follicular adenoma (n=2). The weight of resected thyroid tissue varied from 150 to 420 g.
No patient suffered from bleeding at the thyroidectomy site, neither per-operatively nor in the postoperative period. Until discharge from hospital, no hemodynamic and cardiovascular compromises were noted. Postoperative serum calcium, phosphorus, and thyroid tests were normal in all patients.
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4. Discussion
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Concomitant cardiac surgery and thyroidectomy is only rarely reported in the literature. A MEDLINE search with all possible entries and key-words on this combined procedure (thyroid/cardiac/coronary/valve/surgery) sorted out two single articles [3,4]. Matsuyama et al. [3] reported the case of a 65-year-old woman harboring unstable angina precipitated by hyperthyroidism from Graves’ disease unresponsive to drug therapy. She was operated on for coronary artery bypass grafting, aortic valve replacement, and total thyroidectomy with uneventful postoperative course. This patient was operated on an emergency basis and differs somehow from our patients’ profile. Wolfhard et al. [4] operated on 14 patients with no complications reported.
The anatomical vicinity of the thyroid and the heart facilitates surgical feasibility of this combined staged procedure. Inclusion of both organs in the same operative field allows prompt cardiac intervention in the event of potential failing hemodynamics complicating thyroidectomy under general anesthesia before initiating cardiopulmonary bypass. Moreover, risk of surgical site bleeding is not increased with full-dose heparinization if careful surgical homeostasis is undertaken. Moreover, surveillance of the thyroidectomy site is carried out during the whole period of cardiopulmonary bypass. In consequence, this combined approach avoids the patient any additional independent intervention on the thyroid gland.
In fact, performing thyroidectomy in patients with coronary artery disease candidate for CABG surgery cannot be undertaken without substantial coronary risk from general anesthesia. Thus, thyroidectomy alone preceding CABG surgery in this group of patients could be hazardous, especially in cases of overt hyperthyroidism known to augment myocardial oxygen consumption and thereby worsening ischemic heart disease. This latter argument holds true for postoperative course following cardiac surgery, when hyperthyroidism is least desirable for it predisposes to supraventricular tachyarrhythmias, superimposed on increased myocardial consumption. Adjunction of antiarrhythmic drugs, such as amiodarone, well known to interfere with thyroid gland metabolism, could further obscure management of these patients.
All the aforementioned arguments favor this approach, by assessing its technical feasibility and showing its beneficial impact on the coronary patient. In-depth relation between thyroid hormone levels modification during thyroidectomy and intraoperative as well as immediate postoperative cardiovascular physiology is documented. The effect of thyroid hormone on cardiovascular pathophysiology has been extensively studied [5,6]. Thyroid hormone can increase myocardial inotropy and heart rate and dilate peripheral arteries to increase cardiac output [2]. Hypothyroidism is associated with a decreased cardiac output and concomitant increased vascular resistances [5]. Cardiopulmonary bypass (CPB) per se affects thyroid hormone metabolism [7] and produces acute hypothyroidism by reversing tri-iodothyronine (T3) to reverse the tri-iodothyronine ratio [8]. Indeed, CPB induces a low T3 syndrome up to 3 days after surgery characterized by low T3 and free T3 concentrations, elevated reverse T3 concentrations in the presence of a significant fall of TSH [9]. However, randomized trials failed to demonstrate clinical benefits of T3 administration during cardiac surgery despite mild myocardial performance in the treated group [10–12]. Lack of thyroid hormone is not associated to increased risk from major cardiac surgery nor it is a contraindication to CABG surgery [13].
Since all six operated patients were free from complications in the postoperative period, we believe that thyroidectomy immediately preceding cardiac surgery is a safe procedure. Moreover, none of the patients showed disturbances in thyroid function as assessed by postoperative thyroid blood tests, nor they harbored hemodynamic disturbances such as decreased cardiac output, elevated systemic vascular resistances or increased need for vasoactive drugs.
A potential limitation of this series report is the reduced prevalence of the cases in the settings of cardiac surgery patients. Indeed, our patients constitute 0.23% (six out of 2530) of the population presenting for elective cardiac surgery. Furthermore, thyroid status of the majority of these subjects is unknown because of lack of systematic thyroid screening. For instance, thyroid disease was present in 11.2% of adult patients admitted to elective CABG surgery in one series and this proportion justified preoperative screening of thyroid disorders [1].
While the main purpose of this study was to demonstrate the surgical feasibility of the combined-staged thyroid and cardiac surgery, it would be useful to screen thyroid status in all patients undergoing cardiac surgery in order to assess prevalence of this disorder. Then identifying the subset of patients with surgical thyroid disease would be a further step to select patients for this combined procedure.
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References
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- Jones T.H., Hunter S.M., Price A., Angelini G.D. Should thyroid function be assessed before cardiopulmonary bypass operations?. Ann Thorac Surg 1994;58:434-436.[Abstract]
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Abstract
1. Introduction
