title: Coronary flow reserve after L-thyroxine therapy in Hashimoto's thyroiditis patients with subclinical and overt hypothyroidism.
abstract: OBJECTIVE
  Overt and subclinical hypothyroidism are reported to be associated with increased cardiovascular disease risk. We have used coronary flow reserve (CFR) measurement by trans-thoracic Doppler echocardiography (TTDE) to determine coronary microvascular function in Hashimoto's thyroiditis patients with overt and subclinical hypothyroidism and to evaluate effects of L-thyroxine replacement on coronary endothelial function.
  
  
  METHODS
  In total, 10 overt hypothyroid patients, 10 subclinical hypothyroid patients, and 10 controls were enrolled. FT4, TSH, anti-thyroid antibodies, lipid profile, insulin, glucose, HOMA-IR, physical parameters, and CFR measured by TTDE were recorded before and after 6 months of L: -thyroxine replacement in all groups.
  
  
  RESULTS
  CFR values of all hypothyroid patients at baseline were significantly lower than those in controls. After L: -thyroxine, CFR increased significantly in overt and subclinical hypothyroidism with respect to the baseline measurements (P < 0.05). When baseline and second measurements were evaluated collectively for patients and controls, CFR was positively correlated with FT4 levels (r = 0.31, P = 0.01) and negatively correlated with TSH and HOMA-IR (r = -0.38, P = 0.002 and r = -0.42, P < 0.001, respectively).
  
  
  CONCLUSIONS
  Subclinical as well as overt hypothyroid patients have impaired coronary microvascular function which improved after L: -thyroxine therapy. Treatment of Hashimoto's thyroiditis patients with subclinical hypothyroidism should be considered to improve cardiovascular disease risk.
authors.affiliation: Department of Cardiology, Istanbul Faculty of Medicine, Istanbul University, Arpaemini M. Tatlipinar C., No: 64 D:5, Fatih, Istanbul, Turkey. huseyinoflaz@yahoo.com
authors.forename: Huseyin
authors.initials: H
authors.lastname: Oflaz
authors.forename: Ramazan
authors.initials: R
authors.lastname: Kurt
authors.forename: Fatma
authors.initials: F
authors.lastname: Sen
authors.forename: Imran
authors.initials: I
authors.lastname: Onur
authors.forename: Arif Oguzhan
authors.initials: AO
authors.lastname: Cimen
authors.forename: Ali
authors.initials: A
authors.lastname: Elitok
authors.forename: Kultigin
authors.initials: K
authors.lastname: Turkmen
authors.forename: Burak
authors.initials: B
authors.lastname: Pamukcu
authors.forename: Erdem
authors.initials: E
authors.lastname: Kasikcioglu
authors.forename: Zehra
authors.initials: Z
authors.lastname: Bugra
authors.forename: Fehmi
authors.initials: F
authors.lastname: Mercanoglu
authors.forename: Nese
authors.initials: N
authors.lastname: Ozbey
mesh_terms: D000328:Adult; D002318:Cardiovascular Diseases / Q000453:epidemiology; D016022:Case-Control Studies; D003331:Coronary Vessels / Q000502:physiology*; D004452:Echocardiography; D005260:Female; D005500:Follow-Up Studies; D050031:Hashimoto Disease / Q000150:complications / Q000188:drug therapy*; D006801:Humans; D007037:Hypothyroidism / Q000150:complications / Q000188:drug therapy*; D008297:Male; D008833:Microcirculation / Q000187:drug effects; D008875:Middle Aged; D011446:Prospective Studies; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology; D012307:Risk Factors; D013974:Thyroxine / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D013974:Thyroxine