Hemodynamic changes in hyperthyroidism-related pulmonary hypertension: a prospective echocardiographic study.
BACKGROUND
Recent reports suggest an association between hyperthyroidism and pulmonary hypertension (PHT), although the potential mechanisms and clinical implications remain unclear.


OBJECTIVE
Our objective was to determine the prevalence of PHT related to hyperthyroidism and the associated hemodynamic changes and outcome.


RESULTS
We performed serial echocardiographic examinations in 75 consecutive patients with hyperthyroidism (43 +/- 2 yr, 47 women) to estimate pulmonary artery systolic pressure (PASP), cardiac output (CO), total vascular resistance (TVR), and left ventricular (LV) filling pressure. Examinations were performed at baseline and 6 months after initiation of antithyroid treatment. Results were compared with 35 age- and sex-matched healthy controls. All hyperthyroid patients had normal LV systolic function, and 35 patients (47%) had PHT with PASP of at least 35 mm Hg. There were no significant differences in the clinical characteristics of hyperthyroid patients with or without PHT (all P > 0.05). Nonetheless, those with PHT had significantly higher CO, PASP, peak transmitral early diastolic flow velocity (E), and ratio of E to early diastolic mitral annular velocity (E') compared with those without PHT and controls (all P < 0.05). Hyperthyroid patients with PHT also had significantly lower TVR than controls (P < 0.05). Among the 35 hyperthyroid patients with PHT, 25 (71%) had pulmonary arterial hypertension (PAH) with normal E/E', and 10 (29%) had pulmonary venous hypertension (PVH) with elevated E/E'. Hyperthyroid patients with PAH had a significantly higher CO and a lower TVR compared with those with PVH. In contrast, hyperthyroid patients with PVH had lower E' and a higher E/E' ratio compared with those with PAH. These hemodynamic abnormalities and PHT were reversible in patients with PAH or PVH after restoration to a euthyroid state.


CONCLUSIONS
In patients with hyperthyroidism and normal LV systolic function, up to 47% had PHT due to either PAH with increased CO (70%) or PVH with elevated LV filling pressure (30%). Most importantly, hyperthyroidism-related PHT was largely asymptomatic and reversible after restoration to a euthyroid state.
Siu
Chung-Wah
CW
Cardiology Division, Department of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong, China.
Zhang
Xue-Hua
XH
Yung
Cindy
C
Kung
Annie W C
AW
Lau
Chu-Pak
CP
Tse
Hung-Fat
HF
D000328:Adult; D013956:Antithyroid Agents / Q000627:therapeutic use; D001794:Blood Pressure / Q000502:physiology; D002231:Carbimazole / Q000627:therapeutic use; D002302:Cardiac Output / Q000502:physiology; D004452:Echocardiography; D015150:Echocardiography, Doppler; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006976:Hypertension, Pulmonary / Q000000981:diagnostic imaging* / Q000209:etiology* / Q000503:physiopathology; D006980:Hyperthyroidism / Q000150:complications* / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011441:Propylthiouracil / Q000627:therapeutic use; D011446:Prospective Studies; D016896:Treatment Outcome; D014655:Vascular Resistance / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology
D013956:Antithyroid Agents; D011441:Propylthiouracil; D002231:Carbimazole