Elastic properties of the ascending aorta and left ventricular function in patients with hypothyroidism.
BACKGROUND
We sought to clarify the possible role of elastic properties of the ascending aorta in the development of cardiac disease associated with hypothyroidism (HT).


METHODS
A total of 37 patients with HT (age: 39.3 +/- 8.9 years) and 29 control subjects were studied. Ascending Aortic (Ao) diameter, Ao elastic indexes, strain (AoST), distensibility (AoD), stiffness index (AoSI), and pressure strain modulus were calculated from the echocardiographically derived Ao diameters. Myocardial performance index (MPI), E/A ratio, isovolumetric relaxation time (IVRT), deceleration time (DT) were measured by Doppler echocardiography to assess diastolic LV function. Patients were treated with levothyroxine and followed-up for 6 months. Thyroid function tests and echocardiographic measurements were repeated at the end of the study.


RESULTS
AoD (cm2 dyn(-1) 10(-3)) and AoST (%) were significantly lower (3.8 vs. 6.1; P < 0.001, 7.4 vs. 12.6, P < 0.001; respectively), whereas AoSI was higher in HT patients (6.2 vs. 3.3; P < 0.001). After treatment, AoD and AoST were increased (5.7; P < 0.001 and 11.8; P < 0.001; respectively), whereas AoSI was decreased significantly (3.7; P < 0.001). Also, early/late mitral peak velocity ratio (Emax/Amax) was significantly lower in HT patients (1.19 vs 1.34; P < 0.01), whereas MPI was higher (0.52 vs. 0.42; P < 0.001). MPI showed a strong correlation with aortic root indexes [AoST (r =-0.61/P < 0.001); AoD, (r =-0.57/P < 0.002); AoSI, (r = 0.53/P < 0.005)] in the HT group. After 6 months of therapy, MPI significantly decreased P < 0.001) and E/A ratios were normalized (P < 0.001).


CONCLUSIONS
Ao root functions have an important role on diastolic LV function. Levothyroxine replacement therapy can reverse all of these adverse effects of HT.
Ozhan
Hakan
H
Abant Izzet Baysal University, Duzce Faculty of Medicine, Department of Cardiology, Duzce, Turkey. ozhanhakan@yahoo.com
Yazici
Mehmet
M
Albayrak
Sinan
S
Erbilen
Enver
E
Bulur
Serkan
S
Akdemir
Ramazan
R
Uyan
Cihangir
C
D000328:Adult; D001011:Aorta / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D004548:Elasticity; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D006801:Humans; D006980:Hyperthyroidism / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D009929:Organ Size; D013314:Stress, Mechanical; D014463:Ultrasonography; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology*