Kravtsiv, Shidlovskyi, and Shidlovskyi: Thyrotoxic Cardiomyopathy and Heart Failure in Patients with Toxic Goiter. Changes after Surgery



Problem statement and analysis of the recent research

Long-term results of surgical treatment of toxic goiter are assessed by the level of compensation of postoperative hypothyroidism, incidence of recurrent goiter and thyrotoxicosis, partial or complete laryngeal paresis, postoperative hypoparathyroidism. Almost no attention is paid to the level of compensation and restoration of changes in the heart and vascular system, which inevitably occur under the influence of excessive amounts of thyroid hormones and are combined in a clinical syndrome of thyrotoxic cardiomyopathy or the hyperthyroid heart.

The most typical signs of thyrotoxic cardiomyopathy include tachycardia, transient or permanent atrial fibrillation (AF) and atrial flutter which lead to the development of heart failure (HF) as well as determine its severity. The second most common after sinus tachycardia cause of arrhythmia, cardiac and cerebrovascular death is atrial fibrillation.

However, even radically treated thyrotoxicosis is known to be able to affect life expectancy. Thus, the mortality rate in patients with toxic goiter caused by heart rhythm disorders and heart failure is 1.2 times higher, and in case of cerebrovascular failure - 1.4 times higher compared to the general population [1, 6-9].

Thus, the evident cause of increased mortality among patients with toxic goiter is heart rhythm disorders on the background of thyrotoxic cardiomyopathy. Considering the aforementioned data, the main task of treating these patients consists in studying the severity of cardiac rhythm disorders in thyrotoxic cardiomyopathy and their changes after surgical treatment of thyrotoxicosis. However, in the literature there are only few works mainly of therapeutic and informational nature, which generally do not solve the problem of thyrotoxic cardiomyopathy, its changes and consequences in the remote period after surgical treatment of toxic goiter [2-5].

The objective of the research was to study changes in cardiac disorders in the remote period after surgical treatment of toxic goiter.

Materials and methods

The study included 150 patients operated on for toxic goiter. The cause of thyrotoxicosis in 93 cases was diffuse toxic goiter, in 47 cases it was nodular toxic goiter and in 10 cases thyrotoxicosis was caused by mixed toxic goiter. The average age of patients was from 21 to 78 years. All the patients were divided into two groups depending on the severity of thyrotoxicosis: 48 persons with moderate thyrotoxicosis (MTT) and 102 persons with severe thyrotoxicosis (STT). The duration of thyrotoxicosis ranged from 2 to 7 years. The indications for surgery included recurrent thyrotoxicosis, an increase in the severity of the disease and the general state of patients with toxic goiter. The operation of choice was thyroidectomy. After surgery, patients received thyroid hormone replacement therapy; the dose was determined by the level of TSH within the reference values. In patients with heart rhythm disorders and heart failure Class IIA and Class IIB the dose was selected individually within the range of 0.7 to 1.6 mg/kg.

The severity of heart failure and NYHA functional class were determined using the 6-min walking test. Heart rhythm disorders were evaluated by the results of 24-hour ECG monitoring. These studies were performed before surgery and one year after surgical treatment of thyrotoxicosis.

Long-term results of surgical treatment of toxic goiter were evaluated by the results of examination one year after surgery. The patient’s general condition, adequacy of compensation of postoperative hypothyroidism, changes in the severity of heart failure and cardiac disorders were taken into consideration. To evaluate long-term results they were distributed as follows: good, satisfactory, unsatisfactory results and ineffective treatment.

The results of surgical treatment were considered as good when patients noted a significant improvement in their general condition, or some of them felt well; heart failure was not found or its milder degree was observed; cardiac rhythm disorders being present before surgery were absent. The results of surgical treatment were considered as satisfactory when patients noted the improvement in their general condition. The severity of heart failure after surgery did not change; cardiac disorders being present before surgery changed for the better: they were not defined and/or permanent atrial fibrillation changed to transient one and transient atrial fibrillation disappeared or extrasystoles occurred. The results of surgical treatment were considered as unsatisfactory when patients noted the improvement in their general condition, and cardiac disorders -permanent or transient atrial fibrillation - remained unchanged. Treatment was considered as ineffective when patients did not note any improvement in their general condition after surgery; the severity of heart failure and heart rhythm disorders - permanent atrial fibrillation were unchanged.

Thus, according to the results of examinations, one year after surgery patients with MTT were divided into four subgroups: subgroup I - patients with good results of surgical treatment; subgroup II - patients with satisfactory results of surgical treatment; subgroup III - patients with unsatisfactory results of surgical treatment; subgroup IV – patients who were not diagnosed with cardiac rhythm disorders before surgery and heart failure was defined as Class I HF. The group of patients with STT was also divided into four groups using the same gradation: good, satisfactory, unsatisfactory results and ineffective treatment (Table 1).

Table 1

Distribution of patients according to the results of surgical treatment of thyrotoxicosis

Group and subgroup Severity of thyrotoxicosis
moderate subgroup severe subgroup
Good results 13 (27.1%) I 9 (8.8%) I
Satisfactory results 21 (43.8%) II 36 (35.3%) II
Unsatisfactory results 1 (2.0%) III 33 (32.4%) III
Ineffective treatment 24 (23.5%) IV
No heart rhythm disorders before surgery and heart failure is defined as Class I HF 13 (27.1%) IV

Statistical processing was performed using parametric and nonparametric methods. To assess the differences between quantitative data of groups Student’s t-test was used. The difference was considered statistically significant at p < 0.05.

Results and Discussion

The preliminary analysis of the final results of the research showed that in all patients there were obvious cardiac disorders, manifestations of which increased with increasing severity of heart failure and changed in different ways after surgical treatment of toxic goiter (Table 2).

At admission, in all the patients regardless of the severity of thyrotoxicosis, there was observed tachycardia within the range of 98 to 163 beats per minute without any significant differences between groups and subgroups of patients. With the increase in the severity of heart failure, in addition to disturbances in heart rate, disturbances in the regularity and consistency of heart rate, including extrasystole, transient and persistent AF occurred.

Table 2

Cardiac disorders in patients with toxic goiter

Cardiac disorder Group of patients according to the severity of thyrotoxicosis
moderate (n=48), subgroups severe (n=102), subgroups
1 (n=13) 2 (n=21) 3 (n=1) 4 (n=13) 1 (n=9) 2 (n=36) 3 (n=33) 4 (n=24)
Tachycardia A 13 21 1 13 9 36 33 24
B - - - - - - - -
C - - - - - - - -
Normocardia A 4 5 - 10 7 13 - -
B 13 5 - 13 7 13 - -
C 13 19 - 13 9 28 - -
Extrasystole A 6 - - 3 2 3 - -
B - - - - 2 3 - -
C - - - - - - - -
Transient atrial fibrillation A 3 10 - - - 12 14 -
B - 10 - - - 12 14 -
C - 2 - - - 8 14 -
Persistent atrial fibrillation A - 6 1 - - 8 19 24
B - 6 1 - - 8 19 24
C - - 1 - - - 19 24

Notes:

A - at admission to hospital;

B - after preoperative preparation (before surgery);

C - a year after surgery.

In case of MTT in the subgroup of patients with good outcomes of surgical treatment at admission to the hospital 3 patients were diagnosed with transient AF, 6 patients were diagnosed with extrasystole and 4 patients suffered from heart rhythm disorders, heart failure was defined as Class IIA HF. Heart rhythm disorders disappeared after the preoperative preparation; normocardia occurred and there were no changes in the severity of heart failure. When examining these patients one year after surgery no cardiac rhythm disorders were detected and heart failure was defined as Class I HF. During hospitalization of 21 patients with satisfactory results of surgical treatment in 5 patients there were no heart rhythm disorders; 10 patients were diagnosed with transient AF; 6 patients suffered from persistent AF. All patients had Class IIA HF. There were no changes in cardiac rhythm disorders and heart failure after the preoperative preparation. 1 year after surgery, in all patients the severity of heart failure remained at the preoperative level. In 2 cases persistent AF transformed into transient AF; in the remaining patients normocardia was found. In one case of unsatisfactory results 1 year after surgery heart rhythm disorders and the severity of heart failure did not change. During hospitalization of 13 patients (subgroup IV) 3 patients had Class I HF and 10 patients suffered from Class IIA HF that in 3 cases was accompanied by extrasystole. After the preoperative preparation, all the patients had no cardiac disorders and heart failure was defined as Class I HF. A year after surgery, in 5 patients HF was not defined, and in 8 patients it remained at the preoperative level (Class I HF).

Out of 102 patients with STT good results of surgical treatment of thyrotoxicosis were observed in 9 patients. During hospitalization heart failure was defined as Class IIA HF; extrasystole was detected in 2 cases. After the preoperative preparation both heart failure and heart rhythm disorders were unchanged. After surgery, in all these patients Class I HF was found; there were no heart rhythm disorders. Out of 36 patients with satisfactory results in 13 persons normocardia was diagnosed during hospitalization and after the preoperative preparation. In 23 cases there were cardiac rhythm disorders: extrasystole was diagnosed in 3 patients, transient AF was found in 12 patients, persistent AF was seen in 8 patients. The severity of HF was defined as Class IIA. One year after surgery normocardia was found in 28 cases; transient AF was detected in 8 patients. The severity of heart failure did not change. Unsatisfactory results of surgical treatment of thyrotoxicosis were found in 33 cases. Before surgery, heart failure in these patients was defined as Class IIA HF. All patients had heart rhythm disorders: transient AF was present in 14 persons, persistent AF was detected in 19 persons. The examination one year after surgery revealed that the severity of heart failure and heart rhythm disorders did not change. Surgical treatment was ineffective in 24 patients. All of them suffered from persistent AF and Class IIB HF. A year after surgery, the severity of heart failure and heart rhythm disorders remained at the level of the indicators before surgery.

Summing up the analysis of the impact of surgical treatment of toxic goiter on cardiac function, it should be noted that a year after surgery, the number of patients with heart rhythm disorders reduced. In case of moderate thyrotoxicosis, compared to the data before surgery, the number of patients reduced from 17 to 3, i.e. by 82.4%, and in case of severe thyrotoxicosis the number of patients reduced from 82 to 65 (by 20.7%). In addition, surgical treatment of thyrotoxicosis had a positive impact on the clinical course of heart failure. Among patients with MTT before surgery 13 persons had Class I HF and 35 persons suffered from Class IIA HF; after surgery, in 5 patients there was no heart failure, 21 patients had Class I HF and 22 patients had Class IIA HF. Among patients with severe thyrotoxicosis there were 78 persons with Class IIA HF and 24 persons with Class IIB HF; after surgery there were 9 persons with Class I HF, 69 persons with Class IIA HF and 24 persons with Class IIB HF (Table 3).

Table 3

Heart failure in patients with toxic goiter before and one year after surgical treatment of thyrotoxicosis

Heart failure Groups (severity of thyrotoxicosis)
ТТСТ (n=48) ТТТ (n=102)
before surgery after surgery before surgery after surgery
No HF 5 (10.4%)
Class I HF 13 (27.1%) 21 (43.8%) 9 (8.9%)
Class IIA HF 35 (72.9%) 22 (45.8%) 78 (76.5%) 69 (67.6%)
Class IIB HF 24 (23.5%) 24 (23.5%)

Thus, when assessing the results of surgical treatment considering changes in studied parameters of cardiac rhythm disorders and the severity of heart failure a year after surgery, good and satisfactory results of surgical treatment in patients with MTT were obtained in 47 (97.9%) cases, and in patients with STT they were achieved in 45 (44.1%) cases. It suggests that the overall severity of thyrotoxicosis is an important and determining factor in the development of thyrotoxic cardiomyopathy, heart failure as well as in the prediction of the results of surgical treatment of toxic goiter.

Conclusions

  • Persistent severe thyrotoxicosis results in thyrotoxic cardiomyopathy, heart failure and severe heart arrhythmias.

  • In the remote postoperative period extrasystole transforms into normocardia, and there is no heart failure; transient atrial fibrillation in MTT in 80% of cases changes to normocardia; in 33% of patients with STT it changes to normocardia and a milder degree of heart failure can be observed or there can be no changes in heart failure; persistent atrial fibrillation changes to normocardia in 16% of cases and in 84% of cases it remains unchanged; there are no changes in heart failure.

  • Long-term results of surgical treatment of toxic goiter when performing thyroidectomy depend on the severity of thyrotoxicosis. Good and satisfactory results in MTT are obtained in 98% of cases, and in STT they are achieved in 44% of cases.

Prospects for further research

The results of the research point to the importance of surgical treatment of toxic goiter. To improve long-term results of treating patients it is necessary to continue the research aimed at predicting long-term outcomes and reviewing the indications for surgical treatment.

References

1 

AYu Babenko, EN Grineva, VN Solntsev. Atrial fibrillation in thyrotoxicosis - the determinants of development and preservation. Klinicheskaya i eksperimantalnaya tireodologiya. 2013;1:29-37. Russian.

2 

OA Alekseeva. Clinical and functional state of the cardiovascular system in patients with diffuse toxic goiter in the debut of the disease and in the remote periods after medical and surgical treatment [extended abstract of dissertation for Doctor of Medical Science]. Chelyabinsk; 2010. 18 p.

3 

EV Leynova, AN Zhilina. Factors contributing to the development of changes in the cardiovascular system in thyrotoxicosis, and how to correct them. Mezhdunarodnyy nauchno-issledovatelskiy zhurnal. 2013;3(11):49-51. Russian.

4 

EV Leynova. Analysis of the effectiveness of treatment of cardiovascular complications in patients with thyrotoxicosis [extended abstract of dissertation for Doctor of Medical Science]. Volgograd; 2013. 23 p.

5 

VO Shuper. Clinical and pathogenetic characteristics and effectiveness of comprehensive treatment of patients with hyperthyroid heart [extended abstract of dissertation for Doctor of Medical Science]. Simferopol; 2003. 20 p.

6 

RWV Flynn, TM McDonald, RT Jung, et al. Mortality and vascular outcomes in patients treated for thyroid dysfunction. J Clin Endocrinol Metab. 2006;91(6):2159-2164. doi:10.1210/jc.2005-1833

7 

JA Franklyn, MC Sheppard, P Maisonneuve. Thyroid function and mortality in patients treated for hyperthyroidism. JAMA. 2005;294(1):71-80. doi:10.1001/jama.294.1.71.

8 

F Osman, J Daykin, M Sheppard, et al. Cardiac rhythm abnormalities in thyrotoxicosis - the explanation for excess vascular mortality. J Endocrinol. 2000;164:321-322.

9 

CW Siu, CY Yeung, CP Lau, et al. Incidence, clinical characteristics and outcome of congestive heart failure as the initial presentation in patients with primary hyperthyroidism. Heart. 2007;93(4):483-487. doi:10.1136/hrt.2006.100628



Copyright (c) 2017 V. V. Kravtsiv, V. O. Shidlovskyi, O. V. Shidlovskyi

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