Coronary microcirculatory vasoconstriction is heterogeneously distributed in acutely ischemic myocardium. Export

@article{citeulike:379636, abstract = {The classical model of coronary physiology implies the presence of maximal microcirculatory vasodilation during myocardial ischemia. However, Doppler monitoring of coronary blood flow (CBF) documented severe microcirculatory vasoconstriction during pacing-induced ischemia in patients with coronary artery disease. This study investigates the mechanisms that underlie this paradoxical behavior in nine patients with stable angina and single-vessel coronary disease who were candidates for stenting. While transstenotic pressures were continuously monitored, input CBF (in ml/min) to the poststenotic myocardium was measured by Doppler catheter and angiographic cross-sectional area. Simultaneously, specific myocardial blood flow (MBF, in ml.min(-1).g(-1)) was measured by 133Xe washout. Perfused tissue mass was calculated as CBF/MBF. Measurements were obtained at baseline, during pacing-induced ischemia, and after stenting. CBF and distal coronary pressure values were also measured during pacing with intracoronary adenosine administration. During pacing, CBF decreased to 64 +/- 24\% of baseline and increased to 265 +/- 100\% of ischemic flow after adenosine administration. In contrast, pacing increased MBF to 184 +/- 66\% of baseline, measured as a function of the increased rate-pressure product (r = 0.69; P < 0.05). Thus, during pacing, perfused myocardial mass drastically decreased from 30 +/- 23 to 12 +/- 11 g (P < 0.01). Distal coronary pressure remained stable during pacing but decreased after adenosine administration. Stenting increased perfused myocardial mass to 39 +/- 23 g (P < 0.05 vs. baseline) as a function of the increase in distal coronary pressure (r = 0.71; P < 0.02). In conclusion, the vasoconstrictor response to pacing-induced ischemia is heterogeneously distributed and excludes a tissue fraction from perfusion. Within perfused tissue, the metabolic demand still controls the vasomotor tone.}, address = {Institute of Clinical Physiology, Italian National Research Council, Pisa, Italy. battesto@ifc.cnr.it}, author = {Sambuceti, G. and Marzilli, M. and Mari, A. and Marini, C. and Schluter, M. and Testa, R. and Papini, M. and Marraccini, P. and Ciriello, G. and Marzullo, P. and L'Abbate, A.}, citeulike-article-id = {379636}, citeulike-linkout-0 = {http://dx.doi.org/10.1152/ajpheart.00870.2004}, citeulike-linkout-1 = {http://view.ncbi.nlm.nih.gov/pubmed/15840905}, citeulike-linkout-2 = {http://www.hubmed.org/display.cgi?uids=15840905}, doi = {10.1152/ajpheart.00870.2004}, issn = {0363-6135}, journal = {Am J Physiol Heart Circ Physiol}, keywords = {acute, arteries, circulation, coronary, heterogeneities, ischemia, vasoconstriction}, month = {May}, number = {5}, posted-at = {2005-11-03 18:05:58}, priority = {2}, title = {Coronary microcirculatory vasoconstriction is heterogeneously distributed in acutely ischemic myocardium.}, url = {http://dx.doi.org/10.1152/ajpheart.00870.2004}, volume = {288}, year = {2005} }

TY - JOUR ID - citeulike:379636 L3 - citeulike-article-id:379636 N2 - The classical model of coronary physiology implies the presence of maximal microcirculatory vasodilation during myocardial ischemia. However, Doppler monitoring of coronary blood flow (CBF) documented severe microcirculatory vasoconstriction during pacing-induced ischemia in patients with coronary artery disease. This study investigates the mechanisms that underlie this paradoxical behavior in nine patients with stable angina and single-vessel coronary disease who were candidates for stenting. While transstenotic pressures were continuously monitored, input CBF (in ml/min) to the poststenotic myocardium was measured by Doppler catheter and angiographic cross-sectional area. Simultaneously, specific myocardial blood flow (MBF, in ml.min(-1).g(-1)) was measured by 133Xe washout. Perfused tissue mass was calculated as CBF/MBF. Measurements were obtained at baseline, during pacing-induced ischemia, and after stenting. CBF and distal coronary pressure values were also measured during pacing with intracoronary adenosine administration. During pacing, CBF decreased to 64 +/- 24% of baseline and increased to 265 +/- 100% of ischemic flow after adenosine administration. In contrast, pacing increased MBF to 184 +/- 66% of baseline, measured as a function of the increased rate-pressure product (r = 0.69; P < 0.05). Thus, during pacing, perfused myocardial mass drastically decreased from 30 +/- 23 to 12 +/- 11 g (P < 0.01). Distal coronary pressure remained stable during pacing but decreased after adenosine administration. Stenting increased perfused myocardial mass to 39 +/- 23 g (P < 0.05 vs. baseline) as a function of the increase in distal coronary pressure (r = 0.71; P < 0.02). In conclusion, the vasoconstrictor response to pacing-induced ischemia is heterogeneously distributed and excludes a tissue fraction from perfusion. Within perfused tissue, the metabolic demand still controls the vasomotor tone. IS - 5 JF - Am J Physiol Heart Circ Physiol SN - 0363-6135 AD - Institute of Clinical Physiology, Italian National Research Council, Pisa, Italy. battesto@ifc.cnr.it TI - Coronary microcirculatory vasoconstriction is heterogeneously distributed in acutely ischemic myocardium. VL - 288 KW - acute KW - arteries KW - circulation KW - coronary KW - heterogeneities KW - ischemia KW - vasoconstriction AU - Sambuceti, G AU - Marzilli, M AU - Mari, A AU - Marini, C AU - Schluter, M AU - Testa, R AU - Papini, M AU - Marraccini, P AU - Ciriello, G AU - Marzullo, P AU - L'Abbate, A PY - 2005/05// UR - http://dx.doi.org/10.1152/ajpheart.00870.2004 ER -