In vivo assessment of ventricular-arterial coupling and determinants of coronary blood flow

The interaction between the contracting left ventricle and the conduit arterial tree is of fundamental relevance to cardiovascular functioning, yet remains incompletely characterized. This interaction determines the central aortic blood pressure (CBP) waveform, left ventricular systolic load, coronary perfusion and load on the conduit vascular tree with important implications in a range of disease states including arterial hypertension, heart failure and myocardial ischaemia. The overarching goal of this compendium of work was to investigate ventricular-vascular interaction as manifested by the CBP waveform, with particular attention to its measurement, morphological characteristics, interaction with coronary blood flow and relationship to cardiovascular outcomes. The findings presented in this compendium of work provide further insights into the influence of ventricular vascular interaction on the CBP waveform and coronary blood flow. The following principal conclusions may be drawn: • Non-invasive measurement of CBP is highly device dependent. Errors introduced by calibration to brachial blood pressures may result in significant output error. • Parameters derived from the CBP waveform are predictive of cardiovascular outcome and provide incremental value in risk prediction • Left ventricular systolic motion is temporally associated with morphological features of the CBP waveform, indicating a role for ventricular-vascular interactions in influencing this waveform. • Early diastolic suction generated within the myocardial microcirculation is a critical determinant of coronary blood flow and the response to increased myocardial oxygen consumption. • The presence of an epicardial coronary artery stenosis attenuates the transmission of the two major accelerative waves, in systole and diastole. Restoration of early diastolic suction wave intensity may represent the principal mode by which PCI enhances coronary blood flow