Dynamics of Flow Redistribution and Vascular Remodeling in Response to Selected Vessel Ablation

Overly dense microvascular networks are treated by selective reduction of vascular elements. Inappropriate manipulation of microvessels could result in loss of host tissue function or a worsening of the clinical problem. Here, an experimental and computational model were developed to predict skin microvascular network remodeling in response to selective vessel interruption via multi-photon laser ablation without damage of the host tissue. The microvasculature was imaged non-invasively by bright-field and multi-photon laser microscopy, and Optical Coherence Tomography pre-ablation and up to 30 days post-ablation. A theoretical model of network remodeling was developed to compute intravascular pressure and identify vessels most sensitive to changes in flow direction. Immediately post-ablation, the average artery and vein diameters increased by 14% and 23%, respectively. The maximum arterial remodeling was 2.5x vs. 3.3x for a vein at day 20 post-ablation. By day 30, the average artery diameter remained 11% increased whereas the vein diameter returned to near preablation value. Venous blood flow was restored in the same location while arterial blood was redistributed through remodeling of collateral circulation with minimum angiogenesis. The theoretical model predicts that the vessels most likely to act as collaterals after flow disruption are those most sensitive to distant changes in pressure.