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Published on: March 27, 2018
Impaired exercise capacity in diabetic patients after coronary bypass surgery: effects of diastolic and endothelial
Yen-Wen Wu1, Ching-Ling Hsu, Shoei-Shen Wang
1Department of Internal Medicine, National Taiwan University Hospital, College of Medicine, Taipei, Taiwan.
Insights
Patients with diabetes mellitus after coronary artery bypass graft surgery exhibit impaired diastolic function and reduced exercise capacity. These factors may increase heart failure risk and reduce long-term survival.
Area of Science:
- Cardiology
- Diabetology
- Vascular Medicine
Background:
- Coronary artery bypass graft (CABG) surgery is a common intervention for coronary artery disease.
- Diabetes mellitus (DM) is a prevalent comorbidity that can affect cardiovascular outcomes post-CABG.
- Exercise capacity is a crucial determinant of prognosis in patients post-CABG.
Purpose of the Study:
- To assess the impact of cardiac diastolic and peripheral vascular function on exercise capacity in CABG patients with and without DM.
- To investigate the relationship between exercise capacity, left ventricular (LV) diastolic function, endothelial function, and biochemical markers.
- To utilize tissue Doppler imaging (TDI) and flow-mediated dilatation (FMD) for functional assessments.
Main Methods:
- Evaluated exercise capacity, TDI, and FMD in 51 first-time CABG survivors (23 with DM) an average of 21.6 months post-surgery.
- Compared functional parameters between diabetic and non-diabetic patient groups.
- Analyzed correlations between exercise capacity and diastolic function, endothelial function, and metabolic parameters.
Main Results:
- Diabetic patients demonstrated significantly lower E', A', and peak oxygen uptake (VO(2)peak), with higher E/E' ratios compared to non-diabetic patients (p < 0.05).
- No significant difference in FMD was observed between groups (p = 0.17).
- Negative correlations were found between diastolic parameters (A, E/E') and VO(2)peak, as well as between HbA1c, triglycerides, and VO(2)peak after age adjustment.
Conclusions:
- Diabetic patients post-CABG exhibit more pronounced diastolic dysfunction and impaired oxygen extraction, contributing to reduced exercise capacity.
- These findings suggest a potential increased risk of heart failure and poorer long-term survival in diabetic patients following CABG, even with preserved systolic function.
Objectives:
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.
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