I was reading on the internet that blockages in the smaller arteries may not show on heart tests such as stress echo which could mean cad from a smaller artery. is this true?

Microvascular corona: It has been taught that a maximum negative treadmill stress test, where at least 85% of one's maximal heart rate is reached , rules out clinically significant coronary artery blockages. More recently microvascular coronary artery disease.has been recognized as a cause of cardiac symptoms.& diagnosed by cardiac MRI studies,Cardiac PET scans, or.more recent endothelial function testing.