Abnormal Epicardial Coronary Resistance in Patients With Diffuse Atherosclerosis but “Normal” Coronary Angiography

Abstract

Background-Coronary arteries without focal stenosis at angiography are generally considered non-flow-limiting.However, atherosclerosis is a diffuse process that often remains invisible at angiography. Accordingly, we hypothesized that in patients with coronary artery disease, nonstenotic coronary arteries induce a decrease in pressure along their length due to diffuse coronary atherosclerosis. Methods and Results-Coronary pressure and fractional flow reserve (FFR), as indices of coronary conductance, were obtained from 37 arteries in 10 individuals without atherosclerosis (group I) and from 106 nonstenotic arteries in 62 patients with arteriographic stenoses in another coronary artery (group II). In group I, the pressure gradient between aorta and distal coronary artery was minimal at rest (1Ϯ1 mm Hg) and during maximal hyperemia (3Ϯ3 mm Hg). Corresponding values were significantly larger in group II (5Ϯ4 mm Hg and 10Ϯ8 mm Hg, respectively; both PϽ0.001). The FFR was near unity (0.97Ϯ0.02; range, 0.92 to 1) in group I, indicating no resistance to flow in truly normal coronary arteries, but it was significantly lower (0.89Ϯ0.08; range, 0.69 to 1) in group II, indicating a higher resistance to flow. In 57% of arteries in group II, FFR was lower than the lowest value in group I. In 8% of arteries in group II, FFR was Ͻ0.75, the threshold for inducible ischemia. Conclusion-Diffuse coronary atherosclerosis without focal stenosis at angiography causes a graded, continuous pressure fall along arterial length. This resistance to flow contributes to myocardial ischemia and has consequences for decision-making during percutaneous coronary interventions.

Structural epicardial disease and microvascular function are determinants of an abnormal longitudinal myocardial blood flow difference in cardiovascular risk individuals as determined with PET/CT

“…According to this, a longitudinal, base-to-apex MBF gradient during hyperemic flows, most likely reflecting an impairment of a flow-mediated coronary vasodilation and/or structural CAD, should be more pronounced with higher flow increases as a consequence of higher increases in intracoronary resistance associated with a pressure drop along the epicardial artery. 12 With this in mind, we aimed to investigate whether epicardial structural disease, as evidenced by CTAdetermined coronary morphology, may affect the manifestation of a longitudinal decrease in MBF from the mid to mid-distal segment of the left ventricle (LV) or longitudinal MBF difference during hyperemic flows in cardiovascular risk individuals, and its dependency on the hyperemic flow increase.…”

Doença aterosclerótica difusa desmascarada pela avaliação fisiológica invasiva da circulação coronária

“…It has already been demonstrated by intravascular ultrasound and also by pressure measurements, that the presence of a focal stenosis is almost always associated with diffuse atherosclerosis of coronary vasculature [3][4][5][6] . Even after successful stenting of a focal stenosis, a residual gradient may remain with an abnormal FFR if pressure is measured in the distal part of the artery.…”

“…In diffuse disease, hyperemic decline is often observed and can even be responsible for inducible ischemia 6 .…”

“…Therefore, to evaluate whether the stent has fully re-established the conductance of a previously stenotic stented segment, FFR should be calculated from the ratio of the pressure just distal to just proximal to the stented segment during a pullback maneuver under maximal hyperemia. The pressure gradient between the two edges of the stent indicates the status of the stented segment alone, whereas the pullback pressure recording along the length of the artery indicates the conductance of the entire epicardial artery, including the stented segment 6 , and also indicates if ischemia will be inducible at exercise.…”

“…De Bruyne et al showed that diffusely atherosclerotic epicardial coronary arteries in contrast to truly normal coronary arteries often cause a continuous pressure decline along their length, reduce fractional flow reserve, contribute to myocardial ischemia and abnormal perfusion during exercise and pharmacological vasodilatation, and are identifiable by intracoronary pressure measurements 6 .…”