Clinical study of the hypothesis of endogenous collateral wind on acute coronary syndrome: a review

Comparison of the Clinical Outcomes of Two Physiological Ischemic Training Methods in Patients with Coronary Heart Disease

The aim of the present study was to verify the effectiveness of physiological ischemic training (PIT) in patients with coronary heart disease (CHD) and compare differences in clinical outcomes between isometric exercise training (IET) and cuff inflation training (CIT).

Fifty-five CHD patients were randomized into three groups: IET group (n=19), CIT group (n=18), and no-exercise group (n=18). PIT was practiced in the IET and CIT groups. Changes in systolic blood pressure (SBP) and diastolic blood pressure (DBP) were recorded. The cardiac structure and function were evaluated and vascular endothelial growth factor (VEGF) measured.

SBP and DBP decreased significantly in both PIT groups after 3-month training (P<0.01). Cardiac function and structure were significantly improved in both PIT groups after 3-month training (P<0.01). Cardiac structure and function in the IET group were both superior to those in the CIT group by the end of training (P<0.01). The VEGF level in both PIT groups increased significantly after 3-month training (P<0.01).

PIT was safe and feasible when performed in CHD patients. An appropriate period of PIT helped improve blood pressure and the cardiac structure and function, with the outcome more positive in the IET group.

The evolving concept of physiological ischemia training vs. ischemia preconditioning

Ischemic heart diseases are the leading cause of death with increasing numbers of patients worldwide. Despite advances in revascularization techniques, angiogenic therapies remain highly attractive. Physiological ischemia training, which is first proposed in our laboratory, refers to reversible ischemia training of normal skeletal muscles by using a tourniquet or isometric contraction to cause physiologic ischemia for about 4 weeks for the sake of triggering molecular and cellular mechanisms to promote angiogenesis and formation of collateral vessels and protect remote ischemia areas. Physiological ischemia training therapy augments angiogenesis in the ischemic myocardium by inducing differential expression of proteins involved in energy metabolism, cell migration, protein folding, and generation. It upregulates the expressions of vascular endothelial growth factor, and induces angiogenesis, protects the myocardium when infarction occurs by increasing circulating endothelial progenitor cells and enhancing their migration, which is in accordance with physical training in heart disease rehabilitation. These findings may lead to a new approach of therapeutic angiogenesis for patients with ischemic heart diseases. On the basis of the promising results in animal studies, studies were also conducted in patients with coronary artery disease without any adverse effect in vivo, indicating that physiological ischemia training therapy is a safe, effective and non-invasive angiogenic approach for cardiovascular rehabilitation. Preconditioning is considered to be the most protective intervention against myocardial ischemia-reperfusion injury to date. Physiological ischemia training is different from preconditioning. This review summarizes the preclinical and clinical data of physiological ischemia training and its difference from preconditioning.