An original method for analyzing two-dimensional motion of coronary arteries from X-ray angiogram sequences based on active contour model (snake) is presented. The convergence result of the snake in previous frame is used as the initial guess in current frame. Centerlines of interesting vessel segments at successive time instants can be detected through snake deforming from its initial position to optimal position by minimizing the proper energy function. Measurement of intensity similarity between consecutive frames is encompassed into the energy function to obtain accurate tracking. The effectiveness of the method has been demonstrated on clinical coronary artery angiogram sequences and results are encouraging.
Coronary Angiography ; Coronary Vessels ; physiology ; Humans ; Models, Biological ; Movement

A model of fluid dynamics related to the myocardial bridginged and mural coronary artery was designed and manufactured according to the physical principle and characteristic of the mural coronary artery. The model can imitate systematically well the effect of myocardial bridging on hemodynamic change of the mural coronary artery under different controlled experimental parameter. The methodology is proved to be feasible and has good prosperity of experimental study.
Coronary Vessels ; physiology ; Hemodynamics ; Humans ; Models, Cardiovascular ; Myocardial Bridging

Multi-vessel coronary artery disease (MVD) frequently features ambiguous or intermediate lesions that may be both serial and complex, suggesting that multiple regions require revascularization. Percutaneous coronary intervention (PCI) is associated with various challenges such as appropriate identification of lesions that should be treated, the choice of an optimum revascularization method, and limitations of long-term outcomes. Optimal patient selection and careful targeting of lesions are key when planning treatment. Physiology-guided decision-making (based on the fractional flow reserve) can overcome the current limitations of PCI used to treat MVD regardless of clinical presentation or disease subtype, as confirmed in recent clinical trials. Here, we review the use of physiology-guided PCI for patients with MVD, and their early and late outcomes.
Coronary Artery Disease* ; Coronary Vessels* ; Humans ; Methods ; Patient Selection ; Percutaneous Coronary Intervention* ; Physiology* ; Prognosis

The presence of myocardial ischemia is the most important prognostic factor in patients with ischemic heart disease. Fractional flow reserve (FFR) is a gold standard invasive method used to detect the stenosis-specific myocardial ischemia. FFR-guided revascularization strategy is superior to angiography-guided strategy. The recently developed hyperemia-free index, instantaneous wave free ratio is being actively investigated. A non-invasive FFR derived from coronary CT angiography is now used in clinical practice. Due to rapid expansion of invasive and non-invasive physiologic assessment, comprehensive understanding of the role and potential pitfalls of each modality are required for its application. In this review, we focus on the basic and clinical aspects of physiologic assessment in ischemic heart disease.
Angiography ; Coronary Artery Disease* ; Coronary Vessels* ; Humans ; Ischemia ; Myocardial Ischemia ; Physiology

The objectives of this investigation were to evaluate biomechanical factors in the atherosclerotic process using human in vivo hemodynamic parameters and computed numerical simulation qualitatively and quantitatively. The three-dimensional spatial patterns of steady and pulsatile flows in the left coronary artery were simulated, using a finite volume method. Coronary angiogram and Doppler ultrasound measurement of the proximal left coronary flow velocity were performed in humans. Inlet wave velocity distribution obtained from in vivo data of the intravascular Doppler study allowed for input of in vitro numerical simulation. Hemodynamic variables, such as flow velocity, pressure and shear stress of the left anterior descending coronary bifurcation site were calculated. We found that there were spatial fluctuation of flow-velocity and recirculation areas at the curved outer wall of the left anterior descending coronary artery, which were due to the differences of flow-velocity and shear stress, especially during the declaration phase of pulsatile flow. This study suggests that rheologic properties may be a part of the atherogenic process in the coronary bifurcated and curved areas.
Biomechanics ; Blood Flow Velocity/physiology ; Blood Pressure/physiology ; Coronary Arteriosclerosis/physiopathology* ; Coronary Arteriosclerosis/etiology* ; Coronary Vessels/physiopathology* ; Hemodynamics/physiology* ; Homeostasis/physiology ; Human ; Models, Cardiovascular* ; Pulsatile Flow ; Stress, Mechanical

It has been reported that a change in the cellular redox state may be involved in the regulation of vascular tone, but the underlying mechanism is not fully understood. The present study was designed to investigate the cellular effect of sulfhydryl modifying agents in the coronary artery of rabbit using the tension measurement and whole cell clamping method. The application of diamide, a sulfhydryl oxidizing agent, relaxed the endothelium denuded coronary arteries in a dose dependent manner. The fact that this diamide-induced relaxation was significantly attenuated by a pretreatment of 4-AP, and the coronary arteries precontracted with 100 mM K+ instead of histamine, suggests the involvement of 4-AP sensitive K+ channels in the diamide-induced relaxation of coronary arteries. Whole cell patch clamp studies revealed that the 4-AP sensitive IdK was significantly enhanced by the membrane permeant oxidizing agents, diamide and DTDP, and were reversed by subsequent exposure to the reducing agent, DTT. Neither the membrane impermeant oxidizing or reducing agents, GSSG or GSH, had any effect on the activity of IdK, indicating that intracellular sulfhydryl modification is critical for modulating IdK activity. The Diamide failed to significantly alter the voltage dependence of the activation and inactivation parameters, and did not change the inactivation process, suggesting that diamide increases the number of functional channels without altering their gating properties. Since IdK has been believed to play an important role in regulating membrane potential and arterial tone, our results about the effect of sulfhydryl modifying agents on coronary arterial tone and IdK activity should help understand the pathophysiology of the diseases, where oxidative damage has been implicated.
Animal ; Arteries/physiology ; Arteries/drug effects ; Arteries/cytology ; Coronary Vessels/physiology ; Coronary Vessels/drug effects* ; Coronary Vessels/cytology ; Female ; Male ; Oxidants/pharmacology* ; Potassium Channels/physiology ; Rabbits ; Reducing Agents/pharmacology* ; Sulfhydryl Compounds/metabolism*

The reliability and reliable indexes of quantitative assessment of coronary flow reserve (CFR) by using time-intensity curve (TIC) via myocardial contrast echocardiography were investigated. The TIC variables were obtained by employing acoustic densitometry (AD) technique before and after acetylcholine (Ach) injection in 12 dogs. Meanwhile, the correlation between these variables and CFR was analyzed. Among the variables derived from TIC, peak intensity (PI), area under the curve (AUC) and descending slope (DS) were increased significantly (P < 0.05) with the increase of coronary blood flow after Ach injection. Conversely, time-to-peak (TP), half-time of descent (HT), and mean-transit-time (MTT) were decreased remarkably (P < 0.0001). The PI and AUC ratios from post- to pre-Ach injection were strongly associated with CFR with the correlation coefficient (r) being 0.8366 and 0.8824, respectively. It is reliable by using the variables derived from TIC with myocardial contrast echocardiography to quantitatively evaluate regional myocardial CFR. The PI and AUC ratios from post- to pre-Ach injection are the reliable indexes for quantitative assessment of CFR.
Blood Flow Velocity/physiology ; Contrast Media ; Coronary Circulation/*physiology ; Coronary Vessels/physiology ; Coronary Vessels/ultrasonography ; *Echocardiography/methods ; *Image Processing, Computer-Assisted ; Observer Variation ; Regional Blood Flow/drug effects ; Regional Blood Flow/physiology ; Reproducibility of Results ; Ultrasonography, Interventional

In three isolated organs, spleen, cardiac and skeletal muscles, kinetic studies of red cell washout were carried out by using perfusion of the cell-free, oxygenated Ringer's solution. It is found that in each organ there are slow components for red cells to be emptied out from the vascular lumens ranging 30 to 50 minutes as the desaturation half-time. The slowest decay constants (K) are -1.48 X 10(-3) for spleen, -2.33 X 10(-3) for gastrocnemius muscle, and -4.0 X 10(-3) for cardiac muscle.
Animal ; Cats ; Coronary Vessels* ; Erythrocytes/physiology* ; Microcirculation ; Muscles/blood supply* ; Spleen/blood supply*

To explore the influence of bionic texture coronary stents on hemodynamics, a type of bioabsorbable polylactic acid coronary stents was designed, for which a finite element analysis method was used to carry out simulation analysis on blood flow field after the implantation of bionic texture stents with three different shapes (rectangle, triangle and trapezoid), thus revealing the influence of groove shape and size on hemodynamics, and identifying the optimal solution of bionic texture groove. The results showed that the influence of bionic texture grooves of different shapes and sizes on the lower wall shear stress region had a certain regularity. Specifically, the improvement effect of grooves above 0.06 mm on blood flow characteristics was poor, and the effect of grooves below 0.06 mm was good. Furthermore, the smaller the size is, the better the improvement effect is, and the 0.02 mm triangular groove had the best improvement effect. Based on the results of this study, it is expected that bionic texture stents have provided a new method for reducing in-stent restenosis.
Bionics ; Computer Simulation ; Coronary Vessels ; Hemodynamics/physiology* ; Models, Cardiovascular ; Stents ; Stress, Mechanical

This paper presents an approach for estimating the non-rigid motion of coronary arteries using digital angiographic images. Displacement vectors of vessel points are obtained by finding points correspondences in two successive frames. Smoothness of motion field and vessel deformation measurement are considered in matching, and unmatched regions are also dealt with in the fact that the vessel after deformation may have different size with its original station. The search strategy for optimal matching is carried out using dynamic programming (DP) so that computing cost is reduced. Results of this motion estimation method applied to synthetic and clinical images have shown that the method is accurate, with a root mean square error about one pixel for simulated data. For the case of actual X-ray coronary angiographic images, visual inspection of the detected pairs of points shows that the results are very encouraging.
Angiography, Digital Subtraction ; methods ; Coronary Angiography ; methods ; Coronary Vessels ; physiology ; Humans ; Movement ; Radiographic Image Interpretation, Computer-Assisted