STUDY LIMITATIONS
The major limitation of our study was echo window quality. Good echo window is sine qua non for an accurate speckle tracking imaging. Despite a high quality echocardiography machine we used and experienced cardiologists, we couldn’t overcome this problem completely when particularly the problem is patient related. Another limitation was that we could not exclude microvascular disease in our study. Furthermore, regrettably in some patients coronary lesion severity was evaluated visually and FFR technique was not available for all patients.