Impaired exercise capacity in diabetic patients after coronary bypass surgery: effects of diastolic and endothelial function.
OBJECTIVE
The aims of this study were to clarify the influence of cardiac diastolic and peripheral vascular function on the exercise capacity of patients with coronary bypass surgery (CABG) and diabetes mellitus (DM) by tissue Doppler imaging (TDI) and flow-mediated vasodilatation (FMD), and to investigate interrelations between exercise capacity and LV diastolic function, endothelial function and biochemical parameters.


METHODS
We analyzed the exercise capacity, TDI at the mitral annulus and FMD in 51 uncomplicated first-time CABG survivors (23 DM) at an average interval of 21.6 +/- 12.2 months after surgery.


RESULTS
Diabetics had lower E', A', VO(2)peak, (a-v)O(2) difference, and higher E/E' ratios (p < 0.05) than non-DM patients, but not FMD (p = 0.17). The A and E/E' ratios correlated negatively with VO(2)peak after age adjustment (r = -0.336, p = 0.024). In addition, HbA(1c), and triglyceride also correlated negatively with VO(2)peak (r = -0.377, -0.307, respectively, p < 0.05).


CONCLUSIONS
Diabetics after CABG had more advanced diastolic dysfunction and oxygen extraction impairment than non-DM. It suggests these factors could contribute to lower exercise capacity, risk of developing heart failure despite preserved systolic function and poorer long-term survival of diabetic patients after CABG.
Department of Internal Medicine, National Taiwan University Hospital, College of Medicine, Taipei, Taiwan.
Yen-Wen
YW
Wu
Ching-Ling
CL
Hsu
Shoei-Shen
SS
Wang
Mei-Wun
MW
Tsai
Shu-Hsiun
SH
Chu
Yih-Sharng
YS
Chen
Wei-Shiung
WS
Yang
Ying-Tai
YT
Wu
D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D001916:Brachial Artery; D001026:Coronary Artery Bypass; D003327:Coronary Disease / Q000150:complications / Q000503:physiopathology* / Q000601:surgery; D048909:Diabetes Complications; D003971:Diastole; D015150:Echocardiography, Doppler; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D014664:Vasodilation; D016277:Ventricular Function, Left