Transcoronary intravascular transport functions obtained via a stable deconvolution technique

Following left atrial injection of indocyanine green in closed-chest, anesthetized dogs, 60 simultaneous input-output pairs of dilution curves were sampled via identical catheter sampling systems from the aortic root, C_in(t), and the coronary sinus, C_out(t). Assuming that C_out(t) was the convolution of a transport function, h(t), and C_in(t), a new deconvolution technique was used to solve for the h(t)'s which was not sensitive to noise, recirculation, or the form of h(t). The 60 transcoronary h(t)'s were observed to be unimodal, right-skewed frequency distribution functions with mean transit times, {Mathematical expression}, ranging from 3 to 7 sec. The relative dispersions (standard deviation σ, divided by {Mathematical expression}) averaged 0.38±0.05, the skewness averaged 1.40±0.37 and the kurtosis averaged 6.1±1.8; this means that the h(t)'s are more sharply peaked than Gaussian distributions. The fact that parameters were statistically independent of the mean transit time implied the constancy of the shape of the various h(t)'s and this was verified by the coincidence of the h(t)'s plotted as a function of t/ {Mathematical expression}. This "similarity" of the h(t)'s strongly suggests that changes in the transit time through any particular vascular pathway of the coronary bed are in proportion to the changes in other parallel pathways.