Relation between Myocardial Blood Flow and the Severity of Coronary-Artery Stenosis

Abstract

In humans, basal myocardial blood flow remains constant regardless of the severity of coronary-artery stenosis. However, during hyperemia, flow progressively decreases when the degree of stenosis is about 40 percent or more and does not differ significantly from basal flow when stenosis is 80 percent or greater.

Clinical Quantification of Myocardial Blood Flow Using PET: Joint Position Paper of the SNMMI Cardiovascular Council and the ASNC

“…85 Though initially established using 15 O-water, this finding was quickly replicated using 13 N-ammonia [86][87][88] and more recently using 82 Rb. 89,90 The application of stress MBF and MFR for improving the diagnostic accuracy of PET MPI with clinical protocols has been investigated by many groups with both 13 N-ammonia 47,48,88 and 82 Rb.…”

“…[85][86][87][88] The findings of human studies that have measured MBF and MFR noninvasively by PET, as well as angiographic stenosis severity, can be summarized as follows:…”

“…• In humans, resting MBF remains relatively preserved across a wide range of coronary stenosis severity, 85,86 which is largely related to the gradual autoregulatory vasodilation of resistive vessels to maintain resting myocardial perfusion in the setting of upstream stenosis. Resting MBF falls only in the presence of critical subocclusive stenosis and poorly developed collateral blood flow.…”

“…[85][86][87] • In general, hyperemic MBF and MFR are relatively preserved for coronary lesions with less than 70% angiographic stenosis or with preserved fractional flow reserve (FFR) ([ 0.8). 45,47,51,52,[85][86][87][88][89]91,141,142 However, both Figure 7. Receiver-operator characteristic curves for detection of severe CAD using MFR.…”

The effects of insulin and short-term hyperglycaemia on myocardial blood flow in young men with uncomplicated Type I diabetes

“…PET indicates that coronary vasoreactivity is lower in patients with coronary heart disease (CHD), Type I diabetes, hypertension, and hyperlipidaemias and correlates with the risk factors of CHD even in healthy subjects [28]. The most widely used tracer to measure myocardial perfusion is oxygen-15-labeled water ([ 15 O]-H 2 O) and adenosine induced hyperaemia has been commonly used as a measure of coronary vasoreactivity [29,30].…”