Evidence of a Dominant Backward-Propagating “Suction” Wave Responsible for Diastolic Coronary Filling in Humans, Attenuated in Left Ventricular Hypertrophy

Abstract

Background-Coronary blood flow peaks in diastole when aortic blood pressure has fallen. Current models fail to completely explain this phenomenon. We present a new approach-using wave intensity analysis-to explain this phenomenon in normal subjects and to evaluate the effects of left ventricular hypertrophy (LVH). Method and Results-We measured simultaneous pressure and Doppler velocity with intracoronary wires in the left main stem, left anterior descending, and circumflex arteries of 20 subjects after a normal coronary arteriogram. Wave intensity analysis was used to identify and quantify individual pressure and velocity waves within the coronary artery circulation.A consistent pattern of 6 predominating waves was identified. Ninety-four percent of wave energy, accelerating blood forward along the coronary artery, came from 2 waves: first a pushing wave caused by left ventricular ejection-the dominant forward-traveling pushing wave; and later a suction wave caused by relief of myocardial microcirculatory compression-the dominant backward-traveling suction wave. The dominant backward-traveling suction wave (18.2Ϯ13.7ϫ10 3 W m Ϫ2 s

Caution Using Brachial Systolic Pressure to Calibrate Radial Tonometric Pressure Waveforms: Lessons From Invasive Study

“…Data were recorded and analyzed as described previously. 4 We found that systolic pressure rose progressively in the more peripheral arteries and was 5 mm Hg higher in the radial compared with the brachial artery (PϽ0.002; Table).These findings confirm previous studies showing that there is amplification of brachial systolic pressure and pulse pressure compared with aortic pressure but also indicate that the degree of pressure augmentation between the brachial and radial arteries may be at least as large as the augmentation between the brachial and proximal aortas. These data lend support to the concerns expressed by Segers et al 5 regarding the current practice for the calibration of radial pressure waveforms to brachial artery pressure and directly address the reservations expressed by O'Rourke and Takazawa.…”

“…Data were recorded and analyzed as described previously. 4 We found that systolic pressure rose progressively in the more peripheral arteries and was 5 mm Hg higher in the radial compared with the brachial artery (PϽ0.002; Table).…”

Clinical usefulness of wave intensity analysis

“…The most important one may be coronary blood flow. Sun et al [35,36] reported the results of wave intensity separation analysis in dogs, and Davies et al [7] reported those in humans.…”

Deleterious Effects of Cold Air Inhalation on Coronary Physiological Indices in Patients With Obstructive Coronary Artery Disease

“…Our most striking finding was that in patients with obstructive coronary stenoses, cold air during exercise abrogated the adaptive 200% increase in the backward expansion wave that accompanied exercise in room temperature (Figure 6). This microcirculatory “suction” wave results from the release of external compressive forces on resistance vessels during ventricular relaxation,23 which in turn decreases MVR. This wave is the largest magnitude wave in the cardiac cycle and enables early diastolic coronary flow acceleration following aortic valve closure 23…”

“…Net coronary wave intensity (dI) was calculated as the product of the derivatives of ensemble‐averaged distal coronary pressure (P d ) and Doppler‐flow velocity (CBF), so that: dI=dP d /dt×dCBF/dt 21. We calculated, as previously described,22, 23 the 2 dominant waves that drive coronary perfusion (Figure 2): (1) The forward compression wave, a systolic acceleratory wave generated by sudden increases in aortic pressure at the inlet during ventricular ejection. (2) The backward expansion wave, an early diastolic acceleratory wave generated by microcirculatory suction from the rapid reduction in left ventricular pressure during ventricular relaxation (relieving compression of intramyocardial vessels) 22, 23…”