Effects of Exercise Training on Left Ventricular Function in Type 2 Diabetic Patients Post Coronary Artery Bypass Graft

Study Overview
=================
Brief Summary
-----------------
The purpose of this study is to investigate the changes of cardiorespiratory fitness and left ventricular function in type 2 diabetes after uncomplicated coronary artery bypass graft (CABG) surgery. We hypothesize that exercise capacity, left ventricular diastolic function, and biochemical data improves after 12-wk exercise training in patients with type 2 diabetes underwent CABG.

Detailed Description
-----------------
Patients with type 2 diabetes mellitus have higher incidence of coronary artery disease or left ventricular dysfunction, particularly diastolic dysfunction. Coronary artery bypass surgery is known to decrease the mortality rate in diabetes. Further exercise training can improve their cardiorespiratory fitness and the control of risk factors in these patients. However, the extent of improvement and the mechanism, especially the changes in left ventricular function, in diabetes after exercise training have not been fully explored. Subjects will be assigned to the intervention or control group by randomization. Subjects in the intervention group will receive 60% VO2 max moderate aerobic exercise training, twice per week under supervision and three times per week at home, for 12 weeks. All subjects receive left ventricular function test by echocardiography and impedance cardiography, graded maximal exercise test, and biochemical analyses of sugar and lipid before and after 12 weeks. Their dietary intake and physical activity will be inquired every 4 weeks by questionnaires.

Official Title
-----------------
Effects of Exercise Training on Left Ventricular Function in Type 2 Diabetic Patients Post Coronary Artery Bypass Graft

Conditions
-----------------
Diabetes Mellitus, Non-Insulin-Dependent, Coronary Arteriosclerosis, Post Coronary Artery Bypass Grafting

Intervention / Treatment
-----------------
* Behavioral: Exercise training
* Other: Control


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: well-controlled diabetes no history of myocardial infarction stable post CABG for at least 3 months Exclusion Criteria: heart failure valvular disease abnormal kidney or liver function cerebrovascular disease primary pulmonary disease other systemic or acute illness that may impede the testing or training

Ages Eligible for Study
-----------------
Minimum Age: 40 Years
Maximum Age: 70 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Control<br>Received oral general education about proper diet, regular physcial activity and other medical care if necessary | Other: Control<br>* Subjects received general education including proper diet, regular physical activity or medical care if necessary through an interview with a physical therapist.<br>|
| Experimental: Exercise training<br>Received a supervised structure treadmill training | Behavioral: Exercise training<br>* Subjects attended a supervised treadmill training session three times per week in an outpatient facility for three months. Training duration was 30 minutes per session, including a 5-minute warm-up and cool-down phase. Training intensity was initially set at about 60% of HR reserve and close to the anerobic threshold (AT) and the gradually increased as tolerated.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Exercise capacity | Exercise capacity was assessed by peak oxygen uptake (VO2peak)via exercise testing. VO2peak was measured by a metabolic measurement system (Vmax229 Metabolic Measurement System, Sensor Medics, Anaheim, CA). | Three months after the start of the intervention | 
| Diastolic heart function | Echocardiographic examination including color B mode TDI with a commercially available 2.5- to 3.75-MHz phased array transducer (Philips, SONOS 5500, Andover, MA)was used to evaluate diastolic function. | Three months after the start of the intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Endothelial function | Examined by flow-mediated vasodilation | Three months after the start of the intervention | 
| Hemodynamics | Heart rate (HR) and stroke volume (SV) were collected at rest, during the exercise test, and during the recovery phase by a noninvasive bioimpedance cardiograph device (PhysioFlow PF-05, Manatec Biomedical, Paris, France). Cardiac output (CO) and arteriovenous oxygen difference ((a-v)O2 difference) were then determined by the following equations: CO=HR*SV and (a-v)O2 difference=VO2/SV*HR | Three times after the start of the intervention | 
| Blood test | Including fasting glucose, HbA1c, total cholesterol (TC), high-density liporpotein (HDL-c) and triglyceride (TG). | Three months after the start of the intervention |