Novel Methods for Detection of Coronary Artery Disease in Diabetic Patients 

Ravi Rasalingam, M.D.

Project Overview:
Patients with diabetes are at high risk for heart attacks and may not have the typical warning signs that patients without diabetes experience. Identifying which patient with diabetes will have a heart attack is difficult. Our proposal is designed to assess the ability of sound waves, interacting with the heart of a patient with diabetes while resting, to detect blockages in blood vessels that can cause heart attacks. At present the main way of finding these blockages is to perform a heart stress test where stress is induced by exercise or the use of a medication. This method is expensive, takes time and carries some risk. The current methods also rely heavily on the experience of the person interpreting the test as there are few definitive criteria to define whether the test is abnormal.

The techniques involved in our study involve using sound waves to detect the amount of blood in different regions of the heart corresponding to the course of the supplying blood vessels. We believe that our technique can detect if the amount of blood is reduced by a blockage. We are also measuring twisting and stretching of the heart muscle at different levels and believe that this motion will be reduced in regions of the heart supplied by a blocked blood vessel. The advantage of using these techniques are that they provide easily measurable numbers and can be performed in a regular sound wave test of the heart that is performed in many heart doctor’s offices with no risk to the patient. There is already information supporting the possibility of these techniques detecting changes in heart muscle and its blood supply. No studies in humans have been performed to assess whether specific blood vessels supplying the heart and the amount of blockage present can be detected using these tests.

Many people with diabetes are affected by blocked heart blood vessels which remain one of the most common reasons for poor quality of life and death. Early detection of blocked blood vessels of the heart can allow the use of proven treatments designed to reduce the progression of this problem. It has been shown in a number of studies that the early treatment of the process that causes these blockages can save lives. This is especially important for people with diabetes who are at high risk of developing heart disease and where current methods of screening are especially inadequate. We believe that our proposal will make a significant advancement in developing a screening tool that can reduce the number of people with diabetes suffering from the consequences of heart disease.

Final Report Abstract:
Diabetes is associated with an increased risk of coronary artery disease (CAD) related morbidity and mortality. Significant CAD may be associated with abnormal left ventricular function expressed as altered myocardial deformation characteristics. The purpose of this study was to determine whether resting myocardial deformation and rotation may be altered in diabetic patients with significant CAD with normal left ventricular ejection fraction. Methods and Results: Diabetic patients suspected of CAD scheduled for cardiac catheterization had a resting echocardiogram performed prior to their procedure. An echocardiographer blinded to the cardiac catheterization results performed analysis of longitudinal strain, strain rate, apical rotation and rotation rate. Echocardiographic measurements were compared between patients with and without significant CAD as determined by cardiac catheterization. Read the full Final Report.