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 thatC _out(t) was the convolution of a transport function,h(t), andC _in(t), a new deconvolution technique was used to solve for theh(t)'s which was not sensitive to noise, recirculation, or the form ofh(t). The 60 transcoronaryh(t)'s were observed to be unimodal, right-skewed frequency distribution functions with mean transit times,\(\bar t\), ranging from 3 to 7 sec. The relative dispersions (standard deviation σ, divided by\(\bar t\)) averaged 0.38±0.05, the skewness averaged 1.40±0.37 and the kurtosis averaged 6.1±1.8; this means that theh(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 varioush(t)'s and this was verified by the coincidence of theh(t)'s plotted as a function oft/\(\bar t\). This “similarity” of theh(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.