case single-stage operation for giant substernal goiter
TRANSCRIPT
524 Ann Thorac Cardiovasc Surg Vol. 17, No. 5 (2011)
Single-stage Operation for Giant Substernal Goiter with Severe Coronary Artery Disease
Sonya Wexler, MS,1 Kentaro Yamane, MD,2 Kyle W. Fisher, MD,3
James T. Diehl, MD,2 and Hitoshi Hirose, MD2
1The George Washington University School of Medicine and Health Sciences, Washington DC., USA 2Division of Cardiothoracic Surgery, Department of Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA 3Department of Otolaryngology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
Received: September 13, 2010; Accepted: November 17, 2010 Corresponding author: Hitoshi Hirose, MD. Division of Cardiothoracic Surgery, Department of Surgery, Thomas Jefferson University, 1025 Walnut Street Room 605, Philadelphia, Pennsylvania 19107, USA Email: [email protected] ©2011 The Editorial Committee of Annals of Thoracic and Cardiovascular Surgery. All rights reserved.
A 76-year-old female, with a history of asthma and tracheal bronchitis, presented with a non-ST elevation, myocardial infarction. Chest x-ray on admission showed a widened medi- astinum, which was further evaluated with a computed tomography (CT) scan. It disclosed a giant substernal goiter compressing the trachea and the ascending aorta. Cardiac catheter- ization showed significant coronary disease unsuitable for percutaneous intervention; thus, the patient was scheduled for coronary artery bypass grafting. Single stage thyroidectomy immediately followed by coronary artery bypass was performed. After surgery, her upper airway symptoms were improved, and no cardiac events were noted. Collaboration between otolaryngology and thoracic surgery teams contributed to good outcomes for this patient with substernal goiter and severe cardiac disease.
Keyword: coronary artery disease, thyroid disease, gioter, surgery
Ann Thorac Cardiovasc Surg 2011; 17: 524–527 doi: 10.5761/atcs.cr.10.01628
Introduction
A large substernal goiter may compress the trachea and cause upper airway symptoms.1) Persistent upper air- way obstruction due to substernal goiter may increase stress to the cardiovascular system and also increase the risk of the coronary artery disease (CAD).2) For a goiter located in the mediastinum, sternotomy is sometimes required to access the entire mass rather than approach- ing from the neck alone.1) Here, we report a patient who presented with acute myocardial infarction (MI) and was
found to have a giant substernal goiter with compressive symptoms. The patient underwent single-stage surgery combining thyroidectomy and coronary artery bypass grafting (CABG).
Case Presentation
A 76-year-old female with a past medical history of hypertension, hyperlipidemia, diabetes, obesity, asthma, and chronic tracheobronchitis presented to the emergency department complaining of shortness of breath and wheez- ing. She was unable to lie flat due to severe shortness of breath and stridor. Steroid treatment was started for symp- tomatic upper airway obstruction. The initial workup revealed a non-ST elevation MI. Subsequent cardiac catheterization showed complex CAD (severe proximal stenosis on the left anterior descending artery and bifur- cating lesion on the diagonal artery), which was not suit- able for percutaneous catheter intervention, and poor left ventricular function (ejection fraction 29%). Chest x-ray on admission showed a widened mediastinum (Fig. 1A). CT scan revealed a giant substernal goiter compressing the trachea and aorta (Fig. 1B and 1C). The tracheal diameter was 4 mm at the level of T1-T2. Thyroid function tests
Giant Goiter and CABG
Ann Thorac Cardiovasc Surg Vol. 17, No. 5 (2011) 525
cheal collapse during the surgery, we preserved a site for the emergent tracheostomy and planned to made two sep- arate incisions at the neck and sternum (Fig. 2A). The otolaryngology team performed a curvilinear collar inci- sion to the neck in order to gain access to the upper por- tion of the goiter. The right hemi-thyroid, which appeared to be larger than the left, was dissected first. The subster- nal component of the goiter was unable to be delivered despite transecting the right strap muscles and ligating the middle pole vessels. The cardiothoracic team per- formed a median sternotomy, which allowed access to the lower portion of the goiter. (Fig. 2B). The thyroid tissue was carefully dissected from the thymic remnant and underlying vasculature. The right hemi-thyroid was removed after ligating the inferior pole vessels and transecting the isthmus (Fig. 2C). The left hemi-thyroid and pyramidal lobe were then dissected and delivered in a similar fashion. The parathyroid glands and recurrent laryngeal nerves were preserved. The neck incision was packed with sponges.
The cardiothoracic team then harvested the left inter- nal mammary artery (LIMA) and a saphenous vein graft. Heparin was given before cardiopulmonary bypass. CABG with a LIMA graft to the left anterior descending artery and a saphenous vein graft to the first diagonal artery were performed. Cardiopulmonary bypass was weaned off and protamine was then given to the patient. After completion of the CABG, the neck was examined for hemostasis and 2 Jackson-Pratt drains were placed within the thyroid bed. These were placed to high wall suction and removed by postoperative day 3.
Pathology showed the large thyroid mass consisted of the right lobe, 14 × 8 × 4 cm, left lobe 5.5 × 5 × 2.2 cm, and isthmus 4.5 × 4.2 × 2.2 cm (Fig. 3). Multinodular areas were identified with multiple foci of firm tan-white calcification. Histopathology of the specimen was consis- tent with multinodular goiter.
On postoperative day 1, the patient was electively extu- bated with otolaryngology and anesthesia backup present. No stridor or wheezing was observed after extubation. She did not experience hoarseness or difficulty of swallowing after surgery. On postoperative day 9, the patient was dis- charged home in stable condition with close follow-up with cardiology, otolaryngology, endocrinology and speech pathology. At 2 weeks after discharge from the hospital, laryngoscopy was repeated and revealed normal vocal fold motion. At 6 weeks after discharge from the hospital, she denied any upper airway obstruction symptoms, was free from cardiac events, and returned to her previous activities.
Fig. 1 Preoperative chest x-ray shows widened mediastinum (A). Preoperative CT scan shows narrowed trachea (B) and large substernal goiter (C).
were consistent with a euthyroid state (TSH 0.42 uIU/ml, T3 70 ng/dl, Free T4 1.0 ng/dl, and Free T3 2.3 pg/ml). The patient was scheduled for a combined CABG and thyroidectomy.
In the operating room, an arterial line and Swan-Gantz catheter were placed under local anesthesia. The otolar- yngology team successfully intubate the patient using direct laryngoscopy. To minimize the risk of sudden tra-
A
B
C
526
Ann Thorac Cardiovasc Surg Vol. 17, No. 5 (2011)
rowed more than 50% from the normal size. Stridor at rest is a sign of severe upper airway obstruction, indicat- ing the airway is narrower than 3 mm in diameter.1) The chest CT from our patient showed a 4 mm tracheal nar- rowing. The respiratory symptoms in our patient may have been worsened by her large body habitus and pres- ence of acute MI. She did have CAD risk factors; how- ever, the presence of chronic upper airway obstruction by the giant substernal goiter may have further contributed to accelerating CAD, hypertension, and ventricular dys- function.2)
Surgery for substernal goiter with significant CAD should be planned carefully. Hemodynamic monitoring should be performed before anesthesia induction. The risk of thyrotoxicosis during thyroidectomy is low as long as the patient remains euthyroid or hypothyroid before sur- gery, although thyrotoxicosis can be observed in euthyroid patients.1) The anesthesiology team must be alerted if severe tracheal narrowing exists in a patient with subster- nal goiter. Fiberoptic and rigid bronchoscopes, as well as instruments for emergency tracheostomy, should be made available and opened before anesthesia induction. In a patient with a history of recent acute MI or severe CAD
Fig. 2 Incision plan of this patient (A). A giant substernal goiter is visible from sternotomy incision (B). The right hemithy- roid is delivered from neck incision after additional dis- section from the sternal incision (C).
Comments
The presence of symptomatic airway obstruction in patient with substernal goiter is an indication for thyroi- dectomy in patients with substernal goiter. The upper air- way symptoms may be masked for years due to slow growth of the goiter. The symptoms occasionally mimic tracheobronchitis or asthma, as was the case with our patient’s previous diagnosis.1) Substernal giant goiter is easily diagnosed by CT scan. Patients may complain of respiratory symptoms if their tracheal diameter is nar-
Fig. 3 Pathology specimen of the giant goiter. A large right hemithyroid (A) and smaller left hemithyroid (B).
A
B
C
A
B
Ann Thorac Cardiovasc Surg Vol. 17, No. 5 (2011) 527
(as in this case), desaturation from a difficult airway or catecholamine surge from thyroid disease may increase the risk of perioperative acute MI. Thus, surgery was per- formed through the collaboration of otolaryngology, car- diac surgery and anesthesia teams.
Concomitant surgery for substernal giant goiter and CAD has only been reported by a few researchers in the English literature as far as we know.1, 2) In all cases, including ours, thyroidectomy was performed first with a combination of collar incision and median sternotomy. Dissection of the substernal goiter is often difficult due to the compression to the adjacent mediastinal structures and hemorrhagic degeneration of the goiter. Thus, the thyroidectomy should be done before anticoagulation for CABG to minimize the risk of bleeding. We left the neck wound open during the CABG to monitor for unexpected bleeding from anticoagulation.
Current standards of care for the patient undergoing non-cardiac surgery with severe CAD is to delay the non- cardiac surgery until coronary revascularization because of the risk of perioperative MI.1) As in our patient, the risk of MI is high in patients with recent MI and/or poor ventricular dysfunction.
A two-stage procedure, thyroidectomy after CABG would be difficult to do in a patient such as the one pre- sented herein due to the presence of extensive thyroid tis- sue in the retrosternal space. Since the entire substernal goiter was unable to be removed through the neck inci- sion without the use of sternotomy access, if we had per- formed a two-stage procedure (thyroidectomy after CABG) the patient would have required re-do sternotomy, which carries a substantial risk for injury to cardiac structures and/or grafts. The risk of MI is as high as 40% if the grafts are injured at the time of sternal re-entry.1) Moreover, with the second sternotomy for CABG there is increased scar formation from the previous sternotomy, which can make dissection of the goiter from other medi- astinal structures more difficult than would be with a pri- mary thyroidectomy. Another consideration is sudden swelling of the goiter. Cagli reported a patient with an asymptomatic substernal goiter who had developed acute upper airway obstruction and required emergent thyroi- dectomy after elective CABG.1) Tracheal obstruction clearly occurred after CABG. Cagli speculated that a sys- temic inflammatory response from cardiopulmonary bypass during CABG may have contributed to substantial swelling of the substernal goiter, which resulted in com-
pression of the upper airway followed by acute respiratory failure; thus a two-staged procedure is discouraged.
By combining a thyroidectomy and CABG, the surgi- cal team can take advantage of the proximity of these two organs. That is, if both surgical sites are within the same operating field, they can be accessed at any time during the procedure in case of cardiac or respiratory complica- tions. This single-stage surgery by multiple specialty sur- gical teams can be a significant advantage to patient care.
References
1) Mehta Y, Sujatha P, Juneja R, et al. OPCAB and Thy- roidectomy in a patient with a severely compromised airway. J Cardiothorac Vasc Anesth 2005; 19: 79-82.
2) Dempsey JA, Veasey SC, Morgan BJ, et al. Pathophys- iology of sleep apnea. Physiol Rev 2010; 90: 47-112.
3) Rios A, Rodriguez JM, Balsalobre MD, et al. The value of various definitions of intrathoracic goiter for predicting intra-operative and postoperative complica- tions. Surgery 2010; 147: 233-8.
4) Bento A, Goncalves AP. Asthma mimic—a clinical case report. Rev Port Pneumol 29; 15: 1205-9.
5) Matsuyama K, Ueda Y, Ogino H, et al. Combined car- diac surgery and total thyroidectomy: a case report. Jpn Circ J 1999; 63: 1004-6.
6) Kocak H, Becit N, Erkut B, et al. Combined coronary arterial bypass graft and thyroidectomy in a patient with giant goiter: how reliable is it? Thorac Cardiovasc Surg 2007; 55: 56-8.
7) Tang GH, Feindel CM, Gullane PJ, et al. Combined cardiac surgery and excision of a retrosternal thyroid mass: A case report. J Card Surg 2006; 21: 281-3.
8) American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines; American Society of Echocardiography; American Society of Nuclear Cardiology; Heart Rhythm Society; Society of Cardiovascular Anesthesiologists; Society for Cardiovascular Angiography and Interventions; Society for Vascular Medicine; Society for Vascular Surgery, Fleisher LA, Beckman JA, Brown KA, et al. 2009 ACCF/AHA focused update on perioperative beta blockade incorporated into the ACC/AHA 2007 guidelines on perioperative cardiovascular evaluation and care for noncardiac surgery. J Am Coll Cardiol 2009; 54: e13-e118.
Single-stage Operation for Giant Substernal Goiter with Severe Coronary Artery Disease
Sonya Wexler, MS,1 Kentaro Yamane, MD,2 Kyle W. Fisher, MD,3
James T. Diehl, MD,2 and Hitoshi Hirose, MD2
1The George Washington University School of Medicine and Health Sciences, Washington DC., USA 2Division of Cardiothoracic Surgery, Department of Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA 3Department of Otolaryngology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
Received: September 13, 2010; Accepted: November 17, 2010 Corresponding author: Hitoshi Hirose, MD. Division of Cardiothoracic Surgery, Department of Surgery, Thomas Jefferson University, 1025 Walnut Street Room 605, Philadelphia, Pennsylvania 19107, USA Email: [email protected] ©2011 The Editorial Committee of Annals of Thoracic and Cardiovascular Surgery. All rights reserved.
A 76-year-old female, with a history of asthma and tracheal bronchitis, presented with a non-ST elevation, myocardial infarction. Chest x-ray on admission showed a widened medi- astinum, which was further evaluated with a computed tomography (CT) scan. It disclosed a giant substernal goiter compressing the trachea and the ascending aorta. Cardiac catheter- ization showed significant coronary disease unsuitable for percutaneous intervention; thus, the patient was scheduled for coronary artery bypass grafting. Single stage thyroidectomy immediately followed by coronary artery bypass was performed. After surgery, her upper airway symptoms were improved, and no cardiac events were noted. Collaboration between otolaryngology and thoracic surgery teams contributed to good outcomes for this patient with substernal goiter and severe cardiac disease.
Keyword: coronary artery disease, thyroid disease, gioter, surgery
Ann Thorac Cardiovasc Surg 2011; 17: 524–527 doi: 10.5761/atcs.cr.10.01628
Introduction
A large substernal goiter may compress the trachea and cause upper airway symptoms.1) Persistent upper air- way obstruction due to substernal goiter may increase stress to the cardiovascular system and also increase the risk of the coronary artery disease (CAD).2) For a goiter located in the mediastinum, sternotomy is sometimes required to access the entire mass rather than approach- ing from the neck alone.1) Here, we report a patient who presented with acute myocardial infarction (MI) and was
found to have a giant substernal goiter with compressive symptoms. The patient underwent single-stage surgery combining thyroidectomy and coronary artery bypass grafting (CABG).
Case Presentation
A 76-year-old female with a past medical history of hypertension, hyperlipidemia, diabetes, obesity, asthma, and chronic tracheobronchitis presented to the emergency department complaining of shortness of breath and wheez- ing. She was unable to lie flat due to severe shortness of breath and stridor. Steroid treatment was started for symp- tomatic upper airway obstruction. The initial workup revealed a non-ST elevation MI. Subsequent cardiac catheterization showed complex CAD (severe proximal stenosis on the left anterior descending artery and bifur- cating lesion on the diagonal artery), which was not suit- able for percutaneous catheter intervention, and poor left ventricular function (ejection fraction 29%). Chest x-ray on admission showed a widened mediastinum (Fig. 1A). CT scan revealed a giant substernal goiter compressing the trachea and aorta (Fig. 1B and 1C). The tracheal diameter was 4 mm at the level of T1-T2. Thyroid function tests
Giant Goiter and CABG
Ann Thorac Cardiovasc Surg Vol. 17, No. 5 (2011) 525
cheal collapse during the surgery, we preserved a site for the emergent tracheostomy and planned to made two sep- arate incisions at the neck and sternum (Fig. 2A). The otolaryngology team performed a curvilinear collar inci- sion to the neck in order to gain access to the upper por- tion of the goiter. The right hemi-thyroid, which appeared to be larger than the left, was dissected first. The subster- nal component of the goiter was unable to be delivered despite transecting the right strap muscles and ligating the middle pole vessels. The cardiothoracic team per- formed a median sternotomy, which allowed access to the lower portion of the goiter. (Fig. 2B). The thyroid tissue was carefully dissected from the thymic remnant and underlying vasculature. The right hemi-thyroid was removed after ligating the inferior pole vessels and transecting the isthmus (Fig. 2C). The left hemi-thyroid and pyramidal lobe were then dissected and delivered in a similar fashion. The parathyroid glands and recurrent laryngeal nerves were preserved. The neck incision was packed with sponges.
The cardiothoracic team then harvested the left inter- nal mammary artery (LIMA) and a saphenous vein graft. Heparin was given before cardiopulmonary bypass. CABG with a LIMA graft to the left anterior descending artery and a saphenous vein graft to the first diagonal artery were performed. Cardiopulmonary bypass was weaned off and protamine was then given to the patient. After completion of the CABG, the neck was examined for hemostasis and 2 Jackson-Pratt drains were placed within the thyroid bed. These were placed to high wall suction and removed by postoperative day 3.
Pathology showed the large thyroid mass consisted of the right lobe, 14 × 8 × 4 cm, left lobe 5.5 × 5 × 2.2 cm, and isthmus 4.5 × 4.2 × 2.2 cm (Fig. 3). Multinodular areas were identified with multiple foci of firm tan-white calcification. Histopathology of the specimen was consis- tent with multinodular goiter.
On postoperative day 1, the patient was electively extu- bated with otolaryngology and anesthesia backup present. No stridor or wheezing was observed after extubation. She did not experience hoarseness or difficulty of swallowing after surgery. On postoperative day 9, the patient was dis- charged home in stable condition with close follow-up with cardiology, otolaryngology, endocrinology and speech pathology. At 2 weeks after discharge from the hospital, laryngoscopy was repeated and revealed normal vocal fold motion. At 6 weeks after discharge from the hospital, she denied any upper airway obstruction symptoms, was free from cardiac events, and returned to her previous activities.
Fig. 1 Preoperative chest x-ray shows widened mediastinum (A). Preoperative CT scan shows narrowed trachea (B) and large substernal goiter (C).
were consistent with a euthyroid state (TSH 0.42 uIU/ml, T3 70 ng/dl, Free T4 1.0 ng/dl, and Free T3 2.3 pg/ml). The patient was scheduled for a combined CABG and thyroidectomy.
In the operating room, an arterial line and Swan-Gantz catheter were placed under local anesthesia. The otolar- yngology team successfully intubate the patient using direct laryngoscopy. To minimize the risk of sudden tra-
A
B
C
526
Ann Thorac Cardiovasc Surg Vol. 17, No. 5 (2011)
rowed more than 50% from the normal size. Stridor at rest is a sign of severe upper airway obstruction, indicat- ing the airway is narrower than 3 mm in diameter.1) The chest CT from our patient showed a 4 mm tracheal nar- rowing. The respiratory symptoms in our patient may have been worsened by her large body habitus and pres- ence of acute MI. She did have CAD risk factors; how- ever, the presence of chronic upper airway obstruction by the giant substernal goiter may have further contributed to accelerating CAD, hypertension, and ventricular dys- function.2)
Surgery for substernal goiter with significant CAD should be planned carefully. Hemodynamic monitoring should be performed before anesthesia induction. The risk of thyrotoxicosis during thyroidectomy is low as long as the patient remains euthyroid or hypothyroid before sur- gery, although thyrotoxicosis can be observed in euthyroid patients.1) The anesthesiology team must be alerted if severe tracheal narrowing exists in a patient with subster- nal goiter. Fiberoptic and rigid bronchoscopes, as well as instruments for emergency tracheostomy, should be made available and opened before anesthesia induction. In a patient with a history of recent acute MI or severe CAD
Fig. 2 Incision plan of this patient (A). A giant substernal goiter is visible from sternotomy incision (B). The right hemithy- roid is delivered from neck incision after additional dis- section from the sternal incision (C).
Comments
The presence of symptomatic airway obstruction in patient with substernal goiter is an indication for thyroi- dectomy in patients with substernal goiter. The upper air- way symptoms may be masked for years due to slow growth of the goiter. The symptoms occasionally mimic tracheobronchitis or asthma, as was the case with our patient’s previous diagnosis.1) Substernal giant goiter is easily diagnosed by CT scan. Patients may complain of respiratory symptoms if their tracheal diameter is nar-
Fig. 3 Pathology specimen of the giant goiter. A large right hemithyroid (A) and smaller left hemithyroid (B).
A
B
C
A
B
Ann Thorac Cardiovasc Surg Vol. 17, No. 5 (2011) 527
(as in this case), desaturation from a difficult airway or catecholamine surge from thyroid disease may increase the risk of perioperative acute MI. Thus, surgery was per- formed through the collaboration of otolaryngology, car- diac surgery and anesthesia teams.
Concomitant surgery for substernal giant goiter and CAD has only been reported by a few researchers in the English literature as far as we know.1, 2) In all cases, including ours, thyroidectomy was performed first with a combination of collar incision and median sternotomy. Dissection of the substernal goiter is often difficult due to the compression to the adjacent mediastinal structures and hemorrhagic degeneration of the goiter. Thus, the thyroidectomy should be done before anticoagulation for CABG to minimize the risk of bleeding. We left the neck wound open during the CABG to monitor for unexpected bleeding from anticoagulation.
Current standards of care for the patient undergoing non-cardiac surgery with severe CAD is to delay the non- cardiac surgery until coronary revascularization because of the risk of perioperative MI.1) As in our patient, the risk of MI is high in patients with recent MI and/or poor ventricular dysfunction.
A two-stage procedure, thyroidectomy after CABG would be difficult to do in a patient such as the one pre- sented herein due to the presence of extensive thyroid tis- sue in the retrosternal space. Since the entire substernal goiter was unable to be removed through the neck inci- sion without the use of sternotomy access, if we had per- formed a two-stage procedure (thyroidectomy after CABG) the patient would have required re-do sternotomy, which carries a substantial risk for injury to cardiac structures and/or grafts. The risk of MI is as high as 40% if the grafts are injured at the time of sternal re-entry.1) Moreover, with the second sternotomy for CABG there is increased scar formation from the previous sternotomy, which can make dissection of the goiter from other medi- astinal structures more difficult than would be with a pri- mary thyroidectomy. Another consideration is sudden swelling of the goiter. Cagli reported a patient with an asymptomatic substernal goiter who had developed acute upper airway obstruction and required emergent thyroi- dectomy after elective CABG.1) Tracheal obstruction clearly occurred after CABG. Cagli speculated that a sys- temic inflammatory response from cardiopulmonary bypass during CABG may have contributed to substantial swelling of the substernal goiter, which resulted in com-
pression of the upper airway followed by acute respiratory failure; thus a two-staged procedure is discouraged.
By combining a thyroidectomy and CABG, the surgi- cal team can take advantage of the proximity of these two organs. That is, if both surgical sites are within the same operating field, they can be accessed at any time during the procedure in case of cardiac or respiratory complica- tions. This single-stage surgery by multiple specialty sur- gical teams can be a significant advantage to patient care.
References
1) Mehta Y, Sujatha P, Juneja R, et al. OPCAB and Thy- roidectomy in a patient with a severely compromised airway. J Cardiothorac Vasc Anesth 2005; 19: 79-82.
2) Dempsey JA, Veasey SC, Morgan BJ, et al. Pathophys- iology of sleep apnea. Physiol Rev 2010; 90: 47-112.
3) Rios A, Rodriguez JM, Balsalobre MD, et al. The value of various definitions of intrathoracic goiter for predicting intra-operative and postoperative complica- tions. Surgery 2010; 147: 233-8.
4) Bento A, Goncalves AP. Asthma mimic—a clinical case report. Rev Port Pneumol 29; 15: 1205-9.
5) Matsuyama K, Ueda Y, Ogino H, et al. Combined car- diac surgery and total thyroidectomy: a case report. Jpn Circ J 1999; 63: 1004-6.
6) Kocak H, Becit N, Erkut B, et al. Combined coronary arterial bypass graft and thyroidectomy in a patient with giant goiter: how reliable is it? Thorac Cardiovasc Surg 2007; 55: 56-8.
7) Tang GH, Feindel CM, Gullane PJ, et al. Combined cardiac surgery and excision of a retrosternal thyroid mass: A case report. J Card Surg 2006; 21: 281-3.
8) American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines; American Society of Echocardiography; American Society of Nuclear Cardiology; Heart Rhythm Society; Society of Cardiovascular Anesthesiologists; Society for Cardiovascular Angiography and Interventions; Society for Vascular Medicine; Society for Vascular Surgery, Fleisher LA, Beckman JA, Brown KA, et al. 2009 ACCF/AHA focused update on perioperative beta blockade incorporated into the ACC/AHA 2007 guidelines on perioperative cardiovascular evaluation and care for noncardiac surgery. J Am Coll Cardiol 2009; 54: e13-e118.