Cardiac Hemodynamics, Coronary Circulation and Interventional Cardiology

Abstract

Microcirculation is the functional end of the coronary circulation and it plays a key role in the regulation of coronary blood flow, both on the local and global scales. A good understanding of its function under physiological and pathophysiological conditions is crucial but, because of its micro-scale, access to this part of the coronary circulation is extremely difficult and requires a considerable amount of innovation and new technologies. Dynamics of the coronary circulation provide the true vehicle by which blood supply reaches the myocardium- coronary vasculature is only the conducting component of that vehicle. It is highly unlikely that the pulsatile nature of the flow, the capacitance of the conducting vessels and the constant pounding of coronary vasculature by surrounding tissue are not part of the design, regulation, and function of the coronary circulation. Interventions, whether to assess or to correct coronary stenosis, continue to be the main clinical avenue to dealing with coronary heart disease. Clinical decisions rely heavily on the ability to determine the true morphology of an occlusive lesion, to predict the future course of that lesion and to assess the functional toll on coronary blood supply which it will inflict at each stage.

Analog Electrical Model of the Coronary Circulation in Case of Multiple Revascularizations

“…The other parameters of the model are taken as indicated in Table 1, although the cross-sectional area of the native LAD, LCX, and RCA probably vary during the cardiac contraction. The range of resistance variation (±50%) is chosen according to the experimental observations of Kajiya et al 11 on the compression of arterioles and venules. As expected, a decrease of the capillary resistances induces an increase of Q t and an increase of the resistances (constriction of the capillaries) induces a decrease of the flow rate.…”

Theoretical models for coronary vascular biomechanics: Progress & challenges

“…These experimental observations now include flows in the microcirculation (see reviews of Kajiya et al (2008) and van den Akker et al (2010)) and flows subject to varying mechanical conditions. These latter studies in particular have been instrumental in quantifying phasic variations throughout the cardiac cycle in both animal models (Kimura et al, 1992; Kajiya et al, 1989, 2005) and more recently humans in clinical contexts (see reviews of Spaan et al (2006, 2008), Knaapen et al (2009)). …”