Demonstration of coronary artery flow using transthoracic Doppler echocardiography

Coronary Flow Reserve Is a Comprehensive Indicator of Cardiovascular Risk Factors in Subjects With Chest Pain and Normal Coronary Angiogram

“…9- 21 Although the normal and ischemic ranges of CFR have not been determined as yet, CFR >3.0 has been reported as normal while CFR <2.0 have been suggested to be in an ischemic range in patients with significant epicardial coronary artery stenosis. 11, 12 In terms of cardiovascular risk factor assessment in general, according to the Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III), the risk assessment for determining the 10-year risk for developing coronary heart disease (CHD) in subjects without CHD is carried out using the Framingham risk scoring system with distinction of gender. The risk factors included in the Framingham calculation of 10-year risk are: age, total cholesterol, high-density lipoprotein-cholesterol (HDL-C), systolic blood pressure, treatment for hypertension, and cigarette smoking.…”

Transthoracic Echocardiography in the Assessment of Coronary Arteries

“…As veins are larger, located closer to the right ventricle than arteries and demonstrate a three-phase predominantly systolic flow with very high respiratory variations, it is not very difficult to differentiate between the vessels. Krzanowski et al, 2003 andFoster, 2004, observed that a strong signal confusing coronary artery flow may Fig. 6.…”

“…But in published studies TTE visualization of the left internal mammary artery (IMA) graft has varied from 70% to 100%, the venous grafts to the LAD could be assessed in 91%, to the RCA -in 96%, to the Cx -in 90% (Chirillo et al, 2001(Chirillo et al, , 2004Chong et al, 2004). The Nyquist limits should be set at 20 cm/s for the IMA grafts and 10-12 cm/s for the venous grafts (Youn & Foster, 2004). In the proximal part next to the subclavian artery, patent IMA grafts demonstrate a flow pattern with predominant systolic velocity, and next to distal anastomosis site the flow pattern has predominant diastolic velocity similar to that of the coronary artery.…”

“…However, this method demonstrates some important limitations: it is semiinvasive, and has optimal feasibility in visualizing the flow in only very proximal part of the left anterior descending coronary artery (LAD) (ranging from 69% to 97%) and right coronary artery (RCA) (ranging from 66% to 83%) which allowes the assessment of transstenotic or prestenotic CFR but not poststenotic CFR (Vrublevsky et al, 2001(Vrublevsky et al, , 2004. Until recently, transthoracic echocardiography (TTE) evaluation of the CAD was aimed at the assessment of regional and global left ventricular function (Youn & Foster, 2004). Direct transthoracic visualization of the coronary arteries was attempted in children and occasionally in adults with coronary artery anomalies, arteriovenous fistulas, and aneurysms (Harada et al, 1999;Hiraishi et al, 2000; P.C.…”

Transesophageal Echocardiographic Evaluation of Atherosclerosis

“…53) Investigators have reported that LAD distal flow can be detected by TTE in 94% of patients, 53) but TTE mainly visualizes distal LAD flow. Some investigators have shown that the left circumflex coronary artery (LCX) 54) and right coronary artery (RCA) 55) can be evaluated by transthoracic echocardiography with contrast agents. However, the detection of coronary flow is not satisfactory in the clinical setting.…”