Image-Based Modeling of Blood Flow in Human Coronary Arteries With and Without Bypass Grafts During Rest and Simulated Exercise

2008 ◽  
Author(s):  
Jessica Shih ◽  
Hyun Jin Kim ◽  
Charles A. Taylor
Keyword(s):  
Coronary Artery ◽  
Coronary Bypass ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Ventricular Pressure ◽  
Bypass Grafts ◽  
Heart Model ◽  
Intramyocardial Pressure ◽  
Image Based Modeling ◽  
Lumped Parameter

The number of patients with coronary artery disease continues to rise, with approximately 469,000 coronary bypass procedures in 2005 alone [1]. A priori knowledge of the flow features within the coronary vascular system could prove useful in predicting flow changes due to coronary bypass surgery. Image-based modeling and 3-D computational simulations could be used to compute flow and pressure in a patient-specific manner. However, modeling coronary flow requires knowledge of the intramyocardial pressure that compresses coronary vessels, resulting in decreased flow in systole and increased flow in diastole. Left ventricular pressure can provide an estimate to intramyocardial pressure, but the aortic pressure and left ventricular pressure must be coupled in systole when the aortic valve is open. Previously, we have developed a method to couple a lumped-parameter heart model to the inlet of a 3-D model to compute aortic and ventricular pressure [2]. In this study, we use the lumped-parameter heart model and computational fluid dynamics to calculate flow dynamics in a patient model with coronary artery bypass grafts.

Heart function after injection of small air bubbles in coronary artery of pigs

1993 ◽  
Vol 75 (3) ◽  
pp. 1201-1207 ◽  
Author(s):  
J. H. Van Blankenstein ◽  
C. J. Slager ◽  
J. C. Schuurbiers ◽  
S. Strikwerda ◽  
P. D. Verdouw
Keyword(s):  
Coronary Artery ◽  
Heart Function ◽  
Left Ventricular Pressure ◽  
Relative Increase ◽  
Left Ventricular ◽  
Ventricular Pressure ◽  
Relative Reduction ◽  
Air Bubbles ◽  
First Derivative ◽  
A Minor

By its nature, vaporization of atherosclerotic plaques by laser irradiation or spark erosion may produce a substantial amount of gas. To evaluate the effect of gas embolism possibly caused by vaporization techniques, air bubbles with diameters of 75, 150, or 300 microns, each in a volume of 2 microliters/kg, were selectively injected subproximal in the left anterior descending coronary artery of seven anesthetized pigs (28 +/- 3 kg). Systemic hemodynamics such as heart rate, left ventricular pressure and its peak positive first derivative, and mean arterial pressure did not change after air injection, whereas there was a minor change in peak negative first derivative of left ventricular pressure. After injection of air bubbles there was a maximal relative reduction of systolic segment shortening (SS) in the myocardium supplied by the left anterior descending coronary artery of 27, 45, and 58% for 75-, 150-, and 300-microns bubbles, respectively, and a relative increase of postsystolic SS (PSS) of 148, 200, and 257% for 75-, 150-, and 300-microns bubbles, respectively. Recovery of SS and PSS started after 2 min and was completed after 10 min. A difference in SS and PSS changes between different bubble size injections could be demonstrated. From this study it is clear that depression of regional myocardial function after injection of air bubbles could pass unnoticed on the basis of global hemodynamic measurements.

Regional Left Ventricular Systolic Function in Humans During Off-Pump Coronary Bypass Surgery

Circulation ◽  
1999 ◽  
Vol 100 (suppl_2) ◽  
Author(s):  
Philip M. Brown ◽  
Victor B. Kim ◽  
Bret J. Boyer ◽  
Robert M. Lust ◽  
W. Randolph Chitwood ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Coronary Stenosis ◽  
Systolic Function ◽  
Coronary Bypass ◽  
Inverse Correlation ◽  
Left Ventricular Pressure ◽  
Left Ventricular Systolic Function ◽  
Left Ventricular ◽  
Off Pump ◽  
Clinically Significant

Background —Controversy exists as to whether off-pump CABG with local occlusion results in clinically significant myocardial ischemia during the occlusion period. This study was undertaken to delineate the effects of transient local coronary artery occlusion on regional systolic function. Methods and Results —Eight consenting patients undergoing left internal mammary to left anterior descending coronary artery (LAD) bypass were instrumented with a left ventricular pressure catheter and 2 subepicardial cylindrical ultrasonic dimension transducers placed in the minor axis dimension in the region served by the LAD. A digital sonomicrometer was used to collect data before, during, and after coronary occlusion from which percent systolic shortening and pressure-dimension loops were derived. Measuring devices were removed immediately after the final time point. All patients tolerated the procedure well, and there were no complications. Average duration of local occlusion needed for CABG was 15.9±4.4 minutes (range, 12 to 26 minutes). Local occlusion was associated with a decrease in peak systolic shortening from 5.8±0.8% to 1.8±0.8%. In all cases, function returned to baseline after restoration of flow. Pressure-dimension loops confirmed these findings and no evidence of diastolic creep. Linear repression analysis of degree of stenosis versus change in segmental shortening revealed a significant inverse correlation. Conclusions —Local occlusion of the LAD resulted in a transient decrease in myocardial function during occlusion with complete recovery during reperfusion. This change was less significant with increasing degrees of coronary stenosis. These data suggest that local occlusion is not associated with permanent myocardial injury but that ischemic changes do occur that may be clinically significant, especially in patients with lesser degrees of coronary stenosis.

Prediction of coronary blood flow with a numerical model based on collapsible tube dynamics

1990 ◽  
Vol 258 (5) ◽  
pp. H1606-H1614 ◽  
Author(s):  
C. Guiot ◽  
P. G. Pianta ◽  
C. Cancelli ◽  
T. J. Pedley
Keyword(s):  
Vascular System ◽  
Left Ventricular Pressure ◽  
Pressure Change ◽  
External Pressure ◽  
Left Ventricular ◽  
Lumped Parameter Model ◽  
Ventricular Pressure ◽  
Physiological Data ◽  
Lumped Parameter ◽  
Early Systole

We present a theoretical, hydrodynamic model of the vascular system feeding the left ventricle from which the inflow and outflow waveforms can be predicted given the waveforms of aortic and left ventricular pressure. The main feature of the model is that the central portion of the tubes representing intramyocardial vessels is subjected to an external pressure equal to left ventricular pressure, and they therefore collapse (and empty) when that pressure exceeds the internal pressure. The model is a one-dimensional model, so that the propagation of the collapse waves into the vessels can be properly described; this process takes a finite time, and volume change is not in phase with transmural pressure change. Parameters of the model are assessed from independent physiological data. The predicted inflow waveform is compared with experimental data, and the model is shown to reproduce all the main features, in particular the second minimum of flow rate in late systole as well as the first minimum in early systole. The corresponding lumped-parameter model, which cannot take account of wave propagation, is shown not to agree with experiments and in particular to predict unphysiological spikes in the inflow waveform.

scholarly journals Analysis of left ventricular pressure during isovolumic relaxation in coronary artery disease.

Circulation ◽  
1982 ◽  
Vol 65 (4) ◽  
pp. 690-697 ◽  
Author(s):  
D S Thompson ◽  
C B Waldron ◽  
S M Juul ◽  
N Naqvi ◽  
R H Swanton ◽  
...  
Keyword(s):  
Coronary Artery Disease ◽  
Coronary Artery ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Ventricular Pressure ◽  
Artery Disease ◽  
Isovolumic Relaxation

Intramyocardial Pressure and Coronary Extravascular Resistance

1985 ◽  
Vol 107 (1) ◽  
pp. 46-50 ◽  
Author(s):  
P. D. Stein ◽  
H. N. Sabbah ◽  
M. Marzilli
Keyword(s):  
Blood Flow ◽  
Coronary Blood Flow ◽  
Coronary Flow ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Driving Pressure ◽  
Ventricular Pressure ◽  
Intramyocardial Pressure ◽  
Extravascular Resistance

Intramyocardial pressure is an indicator of coronary extravascular resistance. During systole, pressure in the subendocardium exceeds left ventricular intracavitary pressure; whereas pressure in the subepicardium is lower than left ventricular intracavitary pressure. Conversely, during diastole, subepicardial pressure exceeds both subendocardial pressure and left ventricular pressure. These observations suggest that coronary flow during systole is possible only in the subepicardial layers. During diastole, however, a greater driving pressure is available for perfusion of the subendocardial layers relative to the subepicardial layers. On this basis, measurements of intramyocardial pressure contribute to an understanding of the mechanisms of regulation of the phasic and transmural distribution of coronary blood flow.

scholarly journals Effects of left ventricular pressure on sonicated albumin microbubbles: Evaluation using an isolated rabbit heart model

1994 ◽  
Vol 24 (7) ◽  
pp. 1779-1785 ◽  
Author(s):  
Victor Mor-Avi ◽  
Sanjeev G. Shroff ◽  
Kimberley A. Robinson ◽  
Arthur F. Ng ◽  
Bernard P. Cholley ◽  
...  
Keyword(s):  
Left Ventricular Pressure ◽  
Rabbit Heart ◽  
Left Ventricular ◽  
Ventricular Pressure ◽  
Heart Model ◽  
Isolated Rabbit Heart

Influence of nonuniformity on rate of left ventricular pressure fall in the dog

1989 ◽  
Vol 256 (1) ◽  
pp. H222-H232 ◽  
Author(s):  
W. Y. Lew ◽  
C. M. Rasmussen
Keyword(s):  
Coronary Artery ◽  
Left Ventricle ◽  
Ventricular Function ◽  
Anterior Segment ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Ventricular Pressure ◽  
Low Flow ◽  
High Dose ◽  
Pressure Fall

We examined the influence of nonuniformity in regional ventricular function on the rate of left ventricular pressure fall in 10 anesthetized dogs. Ultrasonic segment gauges were implanted in the midwall of the anterior, lateral, and posterior left ventricle. In seven dogs, nonuniformity was produced by infusing isoproterenol (0.4 microgram/ml) into the mid-left anterior descending coronary artery at low flow (0.5 +/- 0.7 ml/min) and high flow (1.5 +/- 1.2 ml/min) rates, for total doses of 0.1 +/- 0.1 and 0.3 +/- 0.2 micrograms, respectively. This produced a dose-dependent increase in anterior segment shortening so that shortening was completed earlier and marked segment lengthening occurred during isovolumic relaxation. Lateral and posterior segments were not directly stimulated. The heart rate, left ventricular end-diastolic pressure, and peak systolic pressure remained constant. However, tau, the time constant of left ventricular pressure fall, increased from 32 +/- 8 to 37 +/- 10 ms with the low dose, and from 35 +/- 6 to 49 +/- 12 ms with the high dose of isoproterenol. Similar results occurred in two dogs when isoproterenol was infused into the proximal, mid, or distal left anterior descending and in three dogs with infusions in the left circumflex coronary artery. We conclude that nonuniformity of regional left ventricular function is an important and independent factor regulating the rate of pressure fall in the intact ejecting left ventricle.

scholarly journals Coronary Artery Remodeling in a Model of Left Ventricular Pressure Overload Is Influenced by Platelets and Inflammatory Cells

PLoS ONE ◽  
2012 ◽  
Vol 7 (8) ◽  
pp. e40196 ◽  
Author(s):  
Fanmuyi Yang ◽  
Anping Dong ◽  
Paul Mueller ◽  
Jessica Caicedo ◽  
Alyssa Moore Sutton ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Pressure Overload ◽  
Left Ventricular Pressure ◽  
Inflammatory Cells ◽  
Left Ventricular ◽  
Ventricular Pressure ◽  
Artery Remodeling

Effects of regional ischemia and ventricular pacing on LV dP/dtmax-end-diastolic volume relation

1987 ◽  
Vol 252 (5) ◽  
pp. H933-H940 ◽  
Author(s):  
W. C. Little ◽  
R. C. Park ◽  
G. L. Freeman
Keyword(s):  
Coronary Artery ◽  
Right Ventricular ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Ventricular Free Wall ◽  
Ventricular Pressure ◽  
Free Wall ◽  
Ventricular Pacing ◽  
End Diastolic Volume ◽  
The Right

We investigated the effects of coronary artery occlusion and pacing from ventricular sites on the relation of the maximum rate of rise of left ventricular pressure (dP/dtmax) to the end-diastolic volume (VED) in dogs previously instrumented to measure left ventricular pressure and to determine left ventricular volume from three ultrasonically measured dimensions. The dP/dtmax-VED relation was generated by vena caval occlusion and compared with the simultaneously produced end-systolic pressure-end-systolic volume (PES-VES) relation. The dP/dtmax-VED relation was described by a straight line during all conditions. Occlusion of the left circumflex coronary artery produced a rightward shift of the dP/dtmax-VED relation, increasing the volume intercept by 11.3 +/- 5.3 (SD) ml (P less than 0.05). Compared with atrial pacing, the dP/dtmax-VED relation was shifted to the right with the volume intercept increasing by 4.8 +/- 4.4 ml (P less than 0.05) during pacing from the right ventricular free wall, 3.7 +/- 5.0 ml (P less than 0.05) during pacing from the right ventricular apex, and 3.7 +/- 2.4 ml (P less than 0.05) during pacing from the left ventricular free wall. Similar increases were observed in the volume intercepts of the PES-VES relations during coronary occlusion or ventricular pacing. These results are consistent with the predictions of the time-varying elastance model and support its use as a conceptual framework to understand left ventricular performance during isovolumic contraction and at end systole, both in the normal ventricle and the ventricle with regional abnormalities of contraction.

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