Myocardial microvascular perfusion after transfusion of liposome-encapsulated hemoglobin evaluated in cross-circulated rat hearts using tracer digital radiography.
The effect of hemodilution with Neo Red Cell (NRC, liposome-encapsulated hemoglobin) on myocardial perfusion was evaluated in cross-circulated rat hearts under 300-bpm pacing and 100-mmHg perfusion pressure. In NRC-transfused hearts (n = 5), NRC volume fraction and hematocrit were 9% +/- 3% and 22% +/- 4%, respectively; the latter decreased from 43% +/- 3% before NRC transfusion. Coronary perfusion rate and left ventricular isovolemic developed pressure increased after NRC transfusion to 4.6 +/- 1.0 ml/min/g and 127 +/- 32 mmHg from basal values of 2.5 +/- 0.3 ml/min/g and 115 +/- 28 mmHg, respectively. In contrast, the flow increase during reperfusion following 30-s flow cessation decreased from 74% +/- 24% to 64% +/- 24%. The arteriovenous difference in O2 saturation was slightly higher after NRC transfusion. Within-layer regional flow distributions from subepicardium to subendocardium assessed by tracer digital radiography (100-microm resolution) showed that coefficients of variation of flows in 400 x 400-microm regions were 0.41 +/- 0.10 in NRC-transfused hearts and 0.54 +/- 0.11 in nontransfused hearts (n = 5); i.e., the myocardial flow distribution was more uniform in NRC-transfused hearts. These results suggest that NRC is superior to erythrocytes in terms of the homogenization of O2 delivery, indicating its potential therapeutic value in myocardial microcirculatory failure.
Asano
Takahisa
T
Department of Medical Engineering and Systems Cardiology, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192, Japan. taasano@med.kawasaki-m.ac.jp
Matsumoto
Takeshi
T
Tachibana
Hiroyuki
H
Takemoto
Mami
M
Kajiya
Fumihiko
F
D000818:Animals; D001802:Blood Substitutes; D003427:Cross Circulation; D006321:Heart / Q000502:physiology*; D006454:Hemoglobins; D018056:Hemorheology; D008081:Liposomes; D008833:Microcirculation / Q000502:physiology; D010101:Oxygen Consumption; D011856:Radiographic Image Enhancement; D051381:Rats
D001802:Blood Substitutes; D006454:Hemoglobins; D008081:Liposomes