Collateral perfusion

Fuchs S, Baffour R, Zhou YF, Shou M, Pierre A, Tio FO, Weissman NJ, Leon MB, Epstein SB, Kornowski R. Transendocardial delivery of autologous bone marrow enhances collateral perfusion and regional function in pigs with chronic experimental myocardial ischemia. JAm Coll Cardw/2001 37 1726-1732. 

Kamihata H, Matsubara H, Nishiue T, Fujiyama S, Amano K, Iba O, Imada T, Iwasaka T. Improvement of collateral perfusion and regional function by implantation of peripheral blood mononuclear cells into ischemic hibernating myocardium. Arterioscler Thromb Vase Ko/2002 22 1804-1810. 

Kinnaird T, Stabile E, Burnett MS, Shou M, Lee CW, Barr S, Fuchs S, Epstein SE. Local delivery of marrow-derived stromal cells augments collateral perfusion through paracrine mechanisms. Circulation 2004 109 1543-1549. 

Sellke FW, Wang SY Friedman M, et al. Basic FGF enhances endothelium-dependent relaxation of the collateral-perfused coronary microcirculation. Am J Physiol I 994 267(4 Pt 2) H1303-H13 I I. 

Rajanayagam MA, Shou M, Thirumurti V et al. Intracoronary basic fibroblast growth factor enhances myocardial collateral perfusion in dogs. J Am Coll Cardiol 2000 35(2) 519-526. 

Kamihata, H., Matsubara, H., Nishiue, T., Fujiyama, S., Tsutsumi, Y., Ozono, R., Masaki, H., Mori, Y., Iba, O., Tateishi, E., Kosaki, A., Shintani, S., Murohara, T., Imaizumi, T., and Iwasaka, T. 2001. Implantation of bone marrow mononuclear cells into ischemic myocardium enhances collateral perfusion and regional function via side supply of angioblasts, angiogenic ligands, and cytokines. Circulation 4 1046-1052. 

Rajanayagam, M.A., Shou, M., Thirumurti, V., Lazarous, D.F., Quyyumi, A.A., Goncalves, L., Stiber, J., Epstein, S.E., and Unger, E.F. 2000. Intracoronary basic fibroblast growth factor enhances myocardial collateral perfusion in dogs. J. Am. Coll. Cardiol. 35 519-526. 

Fig. 8.7 Nondeconvolution-based perfusion measurements in various hemodynamic conditions. Typical concentration-vs.-time curves are shown illustrating (U) underperfused brain tissue, (C) perfusion via collateral pathways resulting in preserved blood flow but delayed bolus arrival, and (H) postischemic hyperemia. A normal curve is presented for comparison (N). Bolus arrival time (Tmax) is late for collaterally perfused tissue, and is typically late for underperfused tissue, but is often early for hyperperfused tissue. TTP is late for underperfused and collaterally perfused tissue, and is often early for hyperperfused tissue...

If good collateral perfusion is unlikely, one then must consider whether one can afford to let the tissue become ischemic. As an example, it would be very reasonable to embolize a peripheral renal artery branch that was injured during a biopsy and sacrifice a small section of renal parenchyma, since it would have negligible effect on renal function. However if the main renal artery was ruptured during PTA, you would not want to embolize this artery except in dire situations since it would sacrifice the entire kidney. 

It should be noted that, in two of these studies, " the perfusion parameter used to define the mismatch was not CBF or MTT, but instead the time it took for contrast concentration to reach peak concentration in each image voxel after contrast injection ( time to peak or TTP). TTP measurements are often used as rough approximations of MTT measurements because calculation of CBF and MTT are somewhat complex, requiring a mathematical process called deconvolution. The details of deconvolution are beyond the scope of this chapter, and the reader is referred to other sources for further explanation. In many clinical settings, maps of parameters like TTP that do not require deconvolution may be available much more quickly than those that do require deconvolution. TTP is less specific than MTT in detecting underperfused tissue because it does not distinguish between delayed contrast arrival time (such as that related to perfusion via collateral vessels) and truly prolonged intravascular transit time. 

Stable angina pectoris Decreased myocardial oxygen consumption -decreased LV end-diastolic dimension -decreased LV filling pressure -decreased LV systolic pressure -decreased PVR Increased coronary blood flow -epicardial coronary artery dilation -stenotic segment dilation -coronary collateral vessel dilation -increased subendocardial perfusion... 

Increased collateral flow Improved perfusion to ischemic myocardium... 

Hippocampal slices (400-500 frm) were quickly prepared from male Wistar rats (8- to 9-weeks-old) and maintained in a chamber at 35 °C, where they were continuously perfused with artificial cerebrospinal fluid as described in our previous paper [11]. A bipolar tungsten electrode was placed in the stratum radiatum to stimulate Schaffer collateral and commissural afferents. The evoked potential was extracellularly recorded from the pyramidal cell layer of the CA1 subfield with a glass capillary microelectrode. A single test stimulation (0.05 msec duration) was applied at intervals of 30 sec. Drugs were delivered by perfusion. To induce potentiation of the evoked potentials, tetanic stimulation was applied at the same intensity through the same stimulating electrode as used for the test stimulation. The magnitude of LTP was evaluated by the population spike amplitude 30 min after tetanic stimulation. 

Tsurumi, Y., Takeshita, S., Chen, D., Kearney, M., Rossow, S.T., Passeri, J. et al. (1996) Direct intramuscular gene transfer of naked DNA encoding vascular endothelial growth factor augments collateral development and tissue perfusion. Circulation, 94, 3281-3290. 

Preliminary studies of collateral circulation in high grade stenoses or occlusions using ultra fast dynamic MRA with temporal resolution in the range of a second did show delayed contrast enhancement in the affected vascular territory, but did not provide relevant additional information compared with conventional MRI and perfusion techniques probably due to the reduced spatial resolution (Wetzel et al. 2001). A dedicated analysis of collateral circulations, especially extra-intracranially, is still the domain of DSA as far as the exact depiction of anatomical connections is of importance. If the exact anastomotic vascular anatomy is not of primary interest, the collateral supply is better determined by MR perfusion techniques. 

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