Percutaneous transmyocardial revascularization induces angiogenesis: A histologic and 3-dimensional micro computed tomography study

The purpose of this study was to visualize the spatial patterns and connect ion of channels created after percutaneous transmyocardial revascularizatio n (PTMR) in normal porcine hearts, and to estimate the relative contributio ns of transmyocardial and coronary perfusion. Six pigs underwent PTMR creat ing channels using radiofrequency ablative energy. Three-dimensional comput ed tomography imaging of channels 1 hr after PTMR showed the direct connect ion of PTMR channels to the myocardial capillary network and to epicardial coronary vessels. In the heart, examined 28 day after PTMR, there was a fin e, extensive, network of microvessels originating from the site of the orig inal PTMR channel, also connecting the left ventricular cavity to myocardia l capillaries. Histopathologic examination of the l-hr specimens showed num erous regions of myocardial hemorrhage and associated inflammatory cell inf iltration. In the 28-day specimens, newly developed new vascular network su ggested neovascularization within the core of these channel remnants. The i mmunoreactivity for basic fibroblast growth factor (bFGF) and vascular endo thelial growth factor (VEGF) were intense within myocardium and neovascular structure surrounding PTMR channel remnants. The vascular connections occu r by direct communication with existing myocardial vasculature acutely, and angiogenesis in these channel remnant chronically.