- Email: [email protected]
Diagnosis and management of the hypothyroid patient with chest pain
J
THoRAc CARDIOVASC SURG
86:57-60, 1983
Diagnosis and management of the hypothyroid patient with chest pain A retrospective analysis of 38 patients undergoing cardiac catheterization with the diagnoses of hypothyroidism and chest pain revealed 23 to be euthyroid while receiving replacement therapy and 15 to be hypothyroid. Cardiac index was significantly reduced (p < 0.01) in hypothyroid and euthyroid patients with thyroxine values between 4 and 7 JJ.gfdl (2.8 ± 0.7 and 3.0 ± 0.9 Ljminfm2, respectively), compared to euthyroid patients with thyroxine values greater than 7 JJ.gfdl with or without coronary artery disease (4.0 ± 1.2 and 4.0 ± 0.7 Ljminjm 2, respectively). Ten hypothyroid patients underwent coronary artery bypass. There were no deaths, and only one patient required prolonged postoperative intubation. With a mean follow-up of 36 months, there have been no myocardial infarctions and one late death, which occurred at 7 years secondary to stroke. We conclude that preoperative thyroid replacement therapy is theoretically dangerous and may not significantly improve hemodynamics until full replacement is achieved. Coronary bypass grafting can be performed safely despite hypothyroidism with excellent early results.
P. David Myerowitz, M.D., Robert W. Kamienski, M.D., David K. Swanson, Ph.D., Paramjeet S. Chopra, M.D., Herbert A. Berkoff, M.D., George M. Kroncke, M.D., George G. Rowe, M.D., Condon R. Vander Ark, M.D., and Shiraz P. Dhanani, M.D., Madison, Wis.
HypothyrOidism is characterized by general slowing of metabolism. There is a fall in cardiac output and pulse rate. Fluid retention, possibly resulting from inappropriate antidiuretic hormone secretion, results in generalized tissue edema and often a hydropericardium. There is a tendency toward hypercholesterolemia and increased atherosclerosis. Anesthetic problems include hypotension, respiratory center depression, and arrhythmias.' The possibility of thyroid hormone replacement therapy causing acute myocardial ischemia or infarction in patients with symptoms of coronary insufficiency was described by Smyth' in 1938. With the advent of coronary angiography and coronary.artery bypass grafting, several centers have described small series of patients undergoing coronary revascularization prior to or with minimal thyroid replacement therapy.>' The From the Divisions of Thoracic and Cardiovascular Surgery and Cardiology, University of Wisconsin Hospital, Madison, Wis. Received for publication Sept. 8, 1982. Accepted for publication Nov. 4, 1982. Address for reprints: P. David Myerowitz, M.D., Department of Surgery, University of Wisconsin Hospital, 600 Highland Ave., Madison, Wis. 53792.
purposes of this report are (1) to retrospectively analyze the metabolic and hemodynamic characteristics of 38 patients with chest pain and the clinical diagnosis of hypothyroidism, (2) to review the operative experience with 23 of these patients with and without thyroid replacement, and (3) to recommend a prudent method of managing this problem.
Methods We retrospectively reviewed the case records of all patients seen at the University of Wisconsin from January, 1972, to December, 1979, with the diagnoses of angina pectoris and hypothyroidism. Thirty-eight patients (23 euthyroid with replacement therapy and 15 hypothyroid) underwent cardiac catheterization with coronary angiography and right and left heart catheterization by means of the Sones technique. Left ventricular end-diastolic pressure, cardiac index, left ventricular work index, and oxygen consumption were tabulated, and coronary arteriograms were read as left main and one-, two-, or three-vessel disease. Serum total thyroxine and cholesterol were measured in all patients and triglycerides in 30 of 38 patients. This report summarizes, our observations on this group of patients with emphasis on the 10 hypothyroid patients who safely 57
58
I he Journal of Thoracic and Cardiovascular Surgery
Myerowitz et al.
CHEST PAIN (38)
/~
EUTHYROID ON REPLACEMENT (23)
~
/\
CATHETERIZATION
NORMAL (8) 35%
CAD (15) 65%
1\
SURGERY (13)
MEDICAL THERAPY
(2)
HYPOTHYROID (15)
/, ~
CATHETERIZATION
NORMAL (I) 7%
CAD (14) 93%
/\
SURGERY (10)
MEDICAL THERAPY
(4)
Fig. 1. Categorization of 38 hypothyroid patients with chest pain undergoing catheterization.
underwent cardiac catheterization and coronary revascularization.
Results Fig. 1 summarizes the 38 patients who constituted the patient population. Table I outlines the variables measured for each subgroup. Of 23 patients who were euthyroid while receiving thyroid replacement therapy, eight had normal coronary arteries (35%) on catheterization. The mean age of this group was 51 years (range 44 to 55 years) with seven of eight being female. Of the 15 patients with severe coronary artery disease (65%), two (62 and 65-year-old men) were treated medically because of poor left ventricular function and diffuse distal coronary disease. Thirteen patients subsequently underwent successful coronary artery bypass grafting. The mean age of this group was 59 years (range 50 to 66 years) with six female and seven male patients. Of the 15 hypothyroid patients with chest pain who underwent catheterization, only one had normal coronary arteries (7%). This patient was a 50-year-old woman. Of the 14 patients with coronary artery disease (93%), four were treated medically. Three patients had diffuse distal coronary artery disease, two had poor left ventricular function because of previous myocardial infarctions, and one patient refused the operation. The mean age of this group was 57 years (range 54 to 59) with three women and one man. Ten patients underwent successful coronary revascularization. The mean age of this group was 61 years (range 46 to 72 years) with three women and seven men. Four subgroups were subsequently isolated (Table II) to determine whether thyroid replacement prior to operation was beneficial and to compare this group with euthyroid patients who had normal coronary arteries.
With normal thyroxine values in our laboratory being 4 to 12 JLg/dl, hypothyroid was defined as thyroxine less than 4 JLg/dl, low euthyroid as thyroxine 4 to 7 JLg/dl, and high euthyroid as thyroxine 7 to 12 JLg/dl. All hypothyroid patients also had clinical stigmata suggestive of that diagnosis. A subset of patients with thyroxine values above 7 JLg/dl were separated from the euthyroid group who underwent operation to see if the level of thyroid replacement affected the variables that were investigated. Although cholesterol values were all within the normal limits of our laboratory, the hypothyroid group had cholesterol values statistically significantly higher than euthyroid patients with normal coronary arteries (p = 0.05) but not significantly different from euthyroid patients with coronary artery disease. Triglyceride values were not statistically significantly different between groups. Left ventricular end-diastolic pressures were not significantly different between groups. Cardiac index and left ventricular work index were significantly lower in the hypothyroid and low euthyroid group than the euthyroid group with normal coronary arteries (p < 0.Q1 for all comparisons). The hypothyroid group had a significantly lower cardiac index than the high euthyroid group (p < 0.05). Otherwise, there were no statistically significant differences in any hemodynamic variables between the hypothyroid and low euthyroid, the low and high euthyroid, and the high euthyroid and euthyroid with normal coronary arteries groups. Oxygen consumption was significantly lower in the hypothyroid group than the euthyroid group with normal coronary arteries (p < 0.01). Specific attention was paid to the 10 patients who were hypothyroid at the time of cardiac catheterization and coronary bypass grafting. Nine had severe threevessel disease (including two with left main coronary artery stenosis) and one had two-vessel disease. Two to five grafts were placed in each patient (grafting to a mean of 3.3 vesselsper patient). There were no operative deaths. Follow-up ranged from 8 months to 7 years (mean 36 months). There were no myocardial infarctions in the follow-up period. Recurrent angina occurred in one patient because of incomplete revascularization demonstrated at recatheterization postoperatively. His chest pain was controlled by drug therapy. There was one late death in a 72-year-old woman, who had multiple strokes and pneumonia 7 years following the bypass operation. Nine of 10 patients were chemically euthyroid at the time of follow-up study. Eight of 10 patients had received no thyroid replacement therapy at all prior to operation. The other two patients were still clinically and chemically hypothyroid despite small
Volume 86 Number 1
Hypothyroidism and chest pain
July, 1983
59
Table I. Summary of hemodynamics and blood values for each subgroup of thyroid patients Hypothyroid group
Euthyroid group Normal
No. of patients Mean age (yr) Male/female T, (!'g/dl) Cholesterol (rng/dl) Triglycerides (rng/dl) LVEDP (mm Hg) Cardiac index (Lyrnin/m') LV work (kg. m/rnin/rn-) 0, consumption (ml O,jm'/min)
coronary
Operation
Medical therapy
arteries
Operation
10 61 7/3 2.1 276 213 16.9 2.8 4.3 112
4 57 1/3 2.9 245 213 27 2.5 3.7 122
I 50 0/1 2.3 375 187 10 2.0
13 59 7/6 5.1
2.2 79
Normal coronary arteries
Medical therapy
2
223
63 2/0 7.9 150
218 15.9 3.2 4.7 135
25 3.0 5.1 191
8 51 1/7 8.1 214 130* 15.6 4.0 6.3 147
Legend: T,. Thyroxine. LVEDP. Left ventricular end-diastolic pressure. LV. Left ventricular. *Excluding one value of 780 mg/dl.
Table II. Summary data offour subsets of patients to determine the effects of thyroid replacement preoperatively
No. of patients T, (!'g/dl) Cholesterol (rng/dl) Triglycerides (rng/dl) LVEDP (mg Hg) Cardiac index (L/min/m') LV work index (kg· m/rnin/m-) 0, consumption (ml O,/m'/min)
Group I: Hypothyroid, operation
Group II: Euthyroid, operation (T, < 7 !,g/dl)
10 1.7 ± 1.0 276 ± 77* 213 ± III 16.9 ± 5.4 2.8 ± 0.7tt 4.3 ± 1.2t 112 ± 18t
10 4.2 ± 0.8 225 ± 40 178 ± 41 17.0 ± 8.2 3.0 ± 0.9t 4.4 ± J.2t 131 ± 32
Group Ill: Euthyroid, operation (T, > 7 !,g/dl) 7.9 217 298 13.0 4.0 5.3 147
3 ± 0.8 ± 48 ± 187 ± 4.4 ± 1.2 ± 1.7 ± 51
Group IV Euthyroid, normal coronary arteries 8.1 214 130 15.6 4.0 6.3 147
8 ± 4.0 ± 39 ± 36 ± 4.9 ± 0.7 ± 1.2 ± 17
Legend: All values are ± standard deviation. For abbreviations see Table I. *p < 0.05 compared to Group IV. tp < 0.01 compared to Group IV. :j:p < 0.05 compared to Group III.
doses of thyroid replacement preoperatively. One severe adrenal insufficiency developed 1 month postoperatively in one patient after starting thyroid replacement. This was controlled with steroid therapy. The mean follow-up for the 13 euthyroid patients who underwent bypass grafting was 45 months (range 20 to 71 months). Seven of 11 patients (64%) are asymptomatic. Four patients were recatheterized for recurrent chest pain. Two of these four patients had patent grafts. One patient had four of six grafts patent and no further intervention was performed. One patient has stenosis of two of four grafts, but because of distal disease reoperation is not planned. ~ Discussion
The diagnosis and management of angina pectoris in the hypothyroid patient presents the physician with a dilemma. Because of the risk of increasing angina or
myocardial infarction with thyroid hormone replacement, cardiac catheterization in these patients is mandatory. In this series as well as others reported in the literature, this procedure can be accomplished with low morbidity and mortality.'? Standard electrocardiographic diagnosis of myocardial ischemia may be difficult because of inverted T waves and conduction abnormalities that may occur secondary to the hypothyroidism." Cardiac catheterization, therefore, not only accurately defines the presence or absence of coronary artery disease but also determines the severity of such disease, so that an appropriate plan for thyroid replacement therapy can be devised. Although 35% of patients who were receiving thyroid replacement at the time they developed angina pectoris had normal coronary arteries, only one of 15 patients (7%) who were severely hypothyroid had normal coronary arteriograrns. Therefore, the hypothyroid patient with angina pectoris is very likely to
60
The Journal of Thoracic and Cardiovascular Surgery
Myerowitz et al.
have severe coronary artery disease and to be at significant risk of increasing angina or myocardial infarction upon institution of thyroid replacement therapy. Once the coronary anatomy is known and coronary artery bypass is decided upon, the question of preoperative thyroid replacement therapy must be faced. All previous reports have described complications following attempted thyroid replacement preoperatively. Paine and associates,' from the University of Alabama, reported one death in six patients secondary to a massive myocardial infarction when preoperative thyroid replacement therapy was attempted. Nelson, Palmer, and Bowyer' reported one death in three patients in a similar situation. Although Hay and colleagues' reported no deaths with thyroid replacement therapy in nine of 18 hypothyroid patients prior to coronary bypass grafting, four patients had their first myocardial infarction within 1 to 10 months after the initiation of therapy. Nelson, Palmer, and Bowyer' treated one patient who had increased perioperative morbidity secondary to inappropriate secretion of antidiuretic hormone, adynamic ileus, and pneumonia; they recommended early postoperative intravenous thyroid replacement, their patient having done well on this regimen. Paine and associates' reported on three patients receiving minimal thyroid replacement and one receiving no thyroid replacement preoperatively and concluded that thyroid replacement was unnecessary preoperatively. Our group of 10 patients (eight of whom received no thyroid replacement preoperatively) would support the University of Alabama experience. The only significant postoperative morbidity directly related to hypothyroidism was significant adrenal insufficiency, which developed in one patient 1 month postoperatively. The occurrence of adrenal insufficiency secondary to thyroid hormone replacement in myxedema has been described. Latent adrenal insufficiency may be unmasked at this point in therapy. Therefore, these patients should be observed closely in the early phase of thyroid replacement. Although the operative mortality in this small group of patients was low, the cardiac surgeon would be well advised to take special care when handling tissues in these patients. All surgeons involved in this series noted increased friability and edema of the tissues. No patient, however, had either hemodynamic or respiratory problems, as one might expect in the hypothyroid patient. All of the patients but one were extubated on the first postoperative day, as is our routine. Vasopressor support
was required in two of 10 patients and was discontinued within 48 hours of operation. Although hemodynamic parameters including cardiac index, left ventricular work index, and oxygen consumption are significantly depressed below those obtained in normal persons or euthyroid patients with normal coronary arteries who are receiving thyroid replacement therapy, they are not dissimilar from those of euthyroid patients with abnormal coronary arteries. Thyroid replacement preoperatively in doses which did' not bring the thyroxine values up to the midnormal range did not appear to significantly improve hemodynamics. Only when thyroxine values were above 7 /J.gjdl did hemodynamic data appear to improve somewhat. Partial thyroid replacement preoperatively does not appear to be of hemodynamic consequence. Cardiac catheterization and' coronary artery bypass should be performed in the hypothyroid patient with coronary artery disease prior to thyroid replacement therapy. Our series indicates that this can be accomplished with low morbidity and mortality and with good long-term results. Extra care must be taken in handling tissues because of edema and increased friability. Thyroid replacement therapy preoperatively carries a significant risk of increasing angina pectoris, myocardial infarction, and death. Postoperatively, one must be aware that associated endocrinologic abnormalities may be unmasked.
2
3
4
5
6
REFERENCES James ML: Endocrine disease and anesthesia. A review of anesthetic management in pituitary, adrenal and thyroid diseases. Anesthesia 25:232-252, 1970 Smyth CJ: Angina pectoris and myocardial infarction as complications of myxedema with special reference to the danger of treatment with thyroid preparations. Am Heart J 15:552-660, 1938 Paine TO, Rogers WJ, Baxley WA, Russell RO Jr: Coronary arterial surgery in patients with incapacitating angina pectoris and myxedema. Am J CardioI40:226-231, 1977 Nelson JC, Palmer FJ, Bowyer AF: The successful treatment of myxedema and coronary artery disease in patients intolerant of thyroid hormone. Med Arts Sci 28: 15-22, 1974 Hay ID, Duick OS, Vlietstra RE, Maloney JO, Pluth JR: Thyroxin therapy in hypothyroid patients undergoing coronary revascularization. A retrospective analysis. Ann Intern Med 95:456-457, 1981 Cohen RO, Lloyd-Thomas HG: Exercise electrocardiogram in myxoedema. Br Med J 2:327-330, 1966
THoRAc CARDIOVASC SURG
86:57-60, 1983
Diagnosis and management of the hypothyroid patient with chest pain A retrospective analysis of 38 patients undergoing cardiac catheterization with the diagnoses of hypothyroidism and chest pain revealed 23 to be euthyroid while receiving replacement therapy and 15 to be hypothyroid. Cardiac index was significantly reduced (p < 0.01) in hypothyroid and euthyroid patients with thyroxine values between 4 and 7 JJ.gfdl (2.8 ± 0.7 and 3.0 ± 0.9 Ljminfm2, respectively), compared to euthyroid patients with thyroxine values greater than 7 JJ.gfdl with or without coronary artery disease (4.0 ± 1.2 and 4.0 ± 0.7 Ljminjm 2, respectively). Ten hypothyroid patients underwent coronary artery bypass. There were no deaths, and only one patient required prolonged postoperative intubation. With a mean follow-up of 36 months, there have been no myocardial infarctions and one late death, which occurred at 7 years secondary to stroke. We conclude that preoperative thyroid replacement therapy is theoretically dangerous and may not significantly improve hemodynamics until full replacement is achieved. Coronary bypass grafting can be performed safely despite hypothyroidism with excellent early results.
P. David Myerowitz, M.D., Robert W. Kamienski, M.D., David K. Swanson, Ph.D., Paramjeet S. Chopra, M.D., Herbert A. Berkoff, M.D., George M. Kroncke, M.D., George G. Rowe, M.D., Condon R. Vander Ark, M.D., and Shiraz P. Dhanani, M.D., Madison, Wis.
HypothyrOidism is characterized by general slowing of metabolism. There is a fall in cardiac output and pulse rate. Fluid retention, possibly resulting from inappropriate antidiuretic hormone secretion, results in generalized tissue edema and often a hydropericardium. There is a tendency toward hypercholesterolemia and increased atherosclerosis. Anesthetic problems include hypotension, respiratory center depression, and arrhythmias.' The possibility of thyroid hormone replacement therapy causing acute myocardial ischemia or infarction in patients with symptoms of coronary insufficiency was described by Smyth' in 1938. With the advent of coronary angiography and coronary.artery bypass grafting, several centers have described small series of patients undergoing coronary revascularization prior to or with minimal thyroid replacement therapy.>' The From the Divisions of Thoracic and Cardiovascular Surgery and Cardiology, University of Wisconsin Hospital, Madison, Wis. Received for publication Sept. 8, 1982. Accepted for publication Nov. 4, 1982. Address for reprints: P. David Myerowitz, M.D., Department of Surgery, University of Wisconsin Hospital, 600 Highland Ave., Madison, Wis. 53792.
purposes of this report are (1) to retrospectively analyze the metabolic and hemodynamic characteristics of 38 patients with chest pain and the clinical diagnosis of hypothyroidism, (2) to review the operative experience with 23 of these patients with and without thyroid replacement, and (3) to recommend a prudent method of managing this problem.
Methods We retrospectively reviewed the case records of all patients seen at the University of Wisconsin from January, 1972, to December, 1979, with the diagnoses of angina pectoris and hypothyroidism. Thirty-eight patients (23 euthyroid with replacement therapy and 15 hypothyroid) underwent cardiac catheterization with coronary angiography and right and left heart catheterization by means of the Sones technique. Left ventricular end-diastolic pressure, cardiac index, left ventricular work index, and oxygen consumption were tabulated, and coronary arteriograms were read as left main and one-, two-, or three-vessel disease. Serum total thyroxine and cholesterol were measured in all patients and triglycerides in 30 of 38 patients. This report summarizes, our observations on this group of patients with emphasis on the 10 hypothyroid patients who safely 57
58
I he Journal of Thoracic and Cardiovascular Surgery
Myerowitz et al.
CHEST PAIN (38)
/~
EUTHYROID ON REPLACEMENT (23)
~
/\
CATHETERIZATION
NORMAL (8) 35%
CAD (15) 65%
1\
SURGERY (13)
MEDICAL THERAPY
(2)
HYPOTHYROID (15)
/, ~
CATHETERIZATION
NORMAL (I) 7%
CAD (14) 93%
/\
SURGERY (10)
MEDICAL THERAPY
(4)
Fig. 1. Categorization of 38 hypothyroid patients with chest pain undergoing catheterization.
underwent cardiac catheterization and coronary revascularization.
Results Fig. 1 summarizes the 38 patients who constituted the patient population. Table I outlines the variables measured for each subgroup. Of 23 patients who were euthyroid while receiving thyroid replacement therapy, eight had normal coronary arteries (35%) on catheterization. The mean age of this group was 51 years (range 44 to 55 years) with seven of eight being female. Of the 15 patients with severe coronary artery disease (65%), two (62 and 65-year-old men) were treated medically because of poor left ventricular function and diffuse distal coronary disease. Thirteen patients subsequently underwent successful coronary artery bypass grafting. The mean age of this group was 59 years (range 50 to 66 years) with six female and seven male patients. Of the 15 hypothyroid patients with chest pain who underwent catheterization, only one had normal coronary arteries (7%). This patient was a 50-year-old woman. Of the 14 patients with coronary artery disease (93%), four were treated medically. Three patients had diffuse distal coronary artery disease, two had poor left ventricular function because of previous myocardial infarctions, and one patient refused the operation. The mean age of this group was 57 years (range 54 to 59) with three women and one man. Ten patients underwent successful coronary revascularization. The mean age of this group was 61 years (range 46 to 72 years) with three women and seven men. Four subgroups were subsequently isolated (Table II) to determine whether thyroid replacement prior to operation was beneficial and to compare this group with euthyroid patients who had normal coronary arteries.
With normal thyroxine values in our laboratory being 4 to 12 JLg/dl, hypothyroid was defined as thyroxine less than 4 JLg/dl, low euthyroid as thyroxine 4 to 7 JLg/dl, and high euthyroid as thyroxine 7 to 12 JLg/dl. All hypothyroid patients also had clinical stigmata suggestive of that diagnosis. A subset of patients with thyroxine values above 7 JLg/dl were separated from the euthyroid group who underwent operation to see if the level of thyroid replacement affected the variables that were investigated. Although cholesterol values were all within the normal limits of our laboratory, the hypothyroid group had cholesterol values statistically significantly higher than euthyroid patients with normal coronary arteries (p = 0.05) but not significantly different from euthyroid patients with coronary artery disease. Triglyceride values were not statistically significantly different between groups. Left ventricular end-diastolic pressures were not significantly different between groups. Cardiac index and left ventricular work index were significantly lower in the hypothyroid and low euthyroid group than the euthyroid group with normal coronary arteries (p < 0.Q1 for all comparisons). The hypothyroid group had a significantly lower cardiac index than the high euthyroid group (p < 0.05). Otherwise, there were no statistically significant differences in any hemodynamic variables between the hypothyroid and low euthyroid, the low and high euthyroid, and the high euthyroid and euthyroid with normal coronary arteries groups. Oxygen consumption was significantly lower in the hypothyroid group than the euthyroid group with normal coronary arteries (p < 0.01). Specific attention was paid to the 10 patients who were hypothyroid at the time of cardiac catheterization and coronary bypass grafting. Nine had severe threevessel disease (including two with left main coronary artery stenosis) and one had two-vessel disease. Two to five grafts were placed in each patient (grafting to a mean of 3.3 vesselsper patient). There were no operative deaths. Follow-up ranged from 8 months to 7 years (mean 36 months). There were no myocardial infarctions in the follow-up period. Recurrent angina occurred in one patient because of incomplete revascularization demonstrated at recatheterization postoperatively. His chest pain was controlled by drug therapy. There was one late death in a 72-year-old woman, who had multiple strokes and pneumonia 7 years following the bypass operation. Nine of 10 patients were chemically euthyroid at the time of follow-up study. Eight of 10 patients had received no thyroid replacement therapy at all prior to operation. The other two patients were still clinically and chemically hypothyroid despite small
Volume 86 Number 1
Hypothyroidism and chest pain
July, 1983
59
Table I. Summary of hemodynamics and blood values for each subgroup of thyroid patients Hypothyroid group
Euthyroid group Normal
No. of patients Mean age (yr) Male/female T, (!'g/dl) Cholesterol (rng/dl) Triglycerides (rng/dl) LVEDP (mm Hg) Cardiac index (Lyrnin/m') LV work (kg. m/rnin/rn-) 0, consumption (ml O,jm'/min)
coronary
Operation
Medical therapy
arteries
Operation
10 61 7/3 2.1 276 213 16.9 2.8 4.3 112
4 57 1/3 2.9 245 213 27 2.5 3.7 122
I 50 0/1 2.3 375 187 10 2.0
13 59 7/6 5.1
2.2 79
Normal coronary arteries
Medical therapy
2
223
63 2/0 7.9 150
218 15.9 3.2 4.7 135
25 3.0 5.1 191
8 51 1/7 8.1 214 130* 15.6 4.0 6.3 147
Legend: T,. Thyroxine. LVEDP. Left ventricular end-diastolic pressure. LV. Left ventricular. *Excluding one value of 780 mg/dl.
Table II. Summary data offour subsets of patients to determine the effects of thyroid replacement preoperatively
No. of patients T, (!'g/dl) Cholesterol (rng/dl) Triglycerides (rng/dl) LVEDP (mg Hg) Cardiac index (L/min/m') LV work index (kg· m/rnin/m-) 0, consumption (ml O,/m'/min)
Group I: Hypothyroid, operation
Group II: Euthyroid, operation (T, < 7 !,g/dl)
10 1.7 ± 1.0 276 ± 77* 213 ± III 16.9 ± 5.4 2.8 ± 0.7tt 4.3 ± 1.2t 112 ± 18t
10 4.2 ± 0.8 225 ± 40 178 ± 41 17.0 ± 8.2 3.0 ± 0.9t 4.4 ± J.2t 131 ± 32
Group Ill: Euthyroid, operation (T, > 7 !,g/dl) 7.9 217 298 13.0 4.0 5.3 147
3 ± 0.8 ± 48 ± 187 ± 4.4 ± 1.2 ± 1.7 ± 51
Group IV Euthyroid, normal coronary arteries 8.1 214 130 15.6 4.0 6.3 147
8 ± 4.0 ± 39 ± 36 ± 4.9 ± 0.7 ± 1.2 ± 17
Legend: All values are ± standard deviation. For abbreviations see Table I. *p < 0.05 compared to Group IV. tp < 0.01 compared to Group IV. :j:p < 0.05 compared to Group III.
doses of thyroid replacement preoperatively. One severe adrenal insufficiency developed 1 month postoperatively in one patient after starting thyroid replacement. This was controlled with steroid therapy. The mean follow-up for the 13 euthyroid patients who underwent bypass grafting was 45 months (range 20 to 71 months). Seven of 11 patients (64%) are asymptomatic. Four patients were recatheterized for recurrent chest pain. Two of these four patients had patent grafts. One patient had four of six grafts patent and no further intervention was performed. One patient has stenosis of two of four grafts, but because of distal disease reoperation is not planned. ~ Discussion
The diagnosis and management of angina pectoris in the hypothyroid patient presents the physician with a dilemma. Because of the risk of increasing angina or
myocardial infarction with thyroid hormone replacement, cardiac catheterization in these patients is mandatory. In this series as well as others reported in the literature, this procedure can be accomplished with low morbidity and mortality.'? Standard electrocardiographic diagnosis of myocardial ischemia may be difficult because of inverted T waves and conduction abnormalities that may occur secondary to the hypothyroidism." Cardiac catheterization, therefore, not only accurately defines the presence or absence of coronary artery disease but also determines the severity of such disease, so that an appropriate plan for thyroid replacement therapy can be devised. Although 35% of patients who were receiving thyroid replacement at the time they developed angina pectoris had normal coronary arteries, only one of 15 patients (7%) who were severely hypothyroid had normal coronary arteriograrns. Therefore, the hypothyroid patient with angina pectoris is very likely to
60
The Journal of Thoracic and Cardiovascular Surgery
Myerowitz et al.
have severe coronary artery disease and to be at significant risk of increasing angina or myocardial infarction upon institution of thyroid replacement therapy. Once the coronary anatomy is known and coronary artery bypass is decided upon, the question of preoperative thyroid replacement therapy must be faced. All previous reports have described complications following attempted thyroid replacement preoperatively. Paine and associates,' from the University of Alabama, reported one death in six patients secondary to a massive myocardial infarction when preoperative thyroid replacement therapy was attempted. Nelson, Palmer, and Bowyer' reported one death in three patients in a similar situation. Although Hay and colleagues' reported no deaths with thyroid replacement therapy in nine of 18 hypothyroid patients prior to coronary bypass grafting, four patients had their first myocardial infarction within 1 to 10 months after the initiation of therapy. Nelson, Palmer, and Bowyer' treated one patient who had increased perioperative morbidity secondary to inappropriate secretion of antidiuretic hormone, adynamic ileus, and pneumonia; they recommended early postoperative intravenous thyroid replacement, their patient having done well on this regimen. Paine and associates' reported on three patients receiving minimal thyroid replacement and one receiving no thyroid replacement preoperatively and concluded that thyroid replacement was unnecessary preoperatively. Our group of 10 patients (eight of whom received no thyroid replacement preoperatively) would support the University of Alabama experience. The only significant postoperative morbidity directly related to hypothyroidism was significant adrenal insufficiency, which developed in one patient 1 month postoperatively. The occurrence of adrenal insufficiency secondary to thyroid hormone replacement in myxedema has been described. Latent adrenal insufficiency may be unmasked at this point in therapy. Therefore, these patients should be observed closely in the early phase of thyroid replacement. Although the operative mortality in this small group of patients was low, the cardiac surgeon would be well advised to take special care when handling tissues in these patients. All surgeons involved in this series noted increased friability and edema of the tissues. No patient, however, had either hemodynamic or respiratory problems, as one might expect in the hypothyroid patient. All of the patients but one were extubated on the first postoperative day, as is our routine. Vasopressor support
was required in two of 10 patients and was discontinued within 48 hours of operation. Although hemodynamic parameters including cardiac index, left ventricular work index, and oxygen consumption are significantly depressed below those obtained in normal persons or euthyroid patients with normal coronary arteries who are receiving thyroid replacement therapy, they are not dissimilar from those of euthyroid patients with abnormal coronary arteries. Thyroid replacement preoperatively in doses which did' not bring the thyroxine values up to the midnormal range did not appear to significantly improve hemodynamics. Only when thyroxine values were above 7 /J.gjdl did hemodynamic data appear to improve somewhat. Partial thyroid replacement preoperatively does not appear to be of hemodynamic consequence. Cardiac catheterization and' coronary artery bypass should be performed in the hypothyroid patient with coronary artery disease prior to thyroid replacement therapy. Our series indicates that this can be accomplished with low morbidity and mortality and with good long-term results. Extra care must be taken in handling tissues because of edema and increased friability. Thyroid replacement therapy preoperatively carries a significant risk of increasing angina pectoris, myocardial infarction, and death. Postoperatively, one must be aware that associated endocrinologic abnormalities may be unmasked.
2
3
4
5
6
REFERENCES James ML: Endocrine disease and anesthesia. A review of anesthetic management in pituitary, adrenal and thyroid diseases. Anesthesia 25:232-252, 1970 Smyth CJ: Angina pectoris and myocardial infarction as complications of myxedema with special reference to the danger of treatment with thyroid preparations. Am Heart J 15:552-660, 1938 Paine TO, Rogers WJ, Baxley WA, Russell RO Jr: Coronary arterial surgery in patients with incapacitating angina pectoris and myxedema. Am J CardioI40:226-231, 1977 Nelson JC, Palmer FJ, Bowyer AF: The successful treatment of myxedema and coronary artery disease in patients intolerant of thyroid hormone. Med Arts Sci 28: 15-22, 1974 Hay ID, Duick OS, Vlietstra RE, Maloney JO, Pluth JR: Thyroxin therapy in hypothyroid patients undergoing coronary revascularization. A retrospective analysis. Ann Intern Med 95:456-457, 1981 Cohen RO, Lloyd-Thomas HG: Exercise electrocardiogram in myxoedema. Br Med J 2:327-330, 1966