Summary
In 24 unanesthetized dogs, we monitored reactive hyperemia responses in the coronary vascular bed after different durations of coronary occlusion and during coronary artery reperfusion. After two hours of occlusion, no significant changes in functional capacity occurred, evidenced by unchanged peak reactive hyperemia, reactive hyperemia flow and repayment of flow debt responses. With occlusions of six hours or more, these responses were impaired upon reperfusion, and remained diminished for up to five days. In those animals reperfused after two and six hours of coronary occlusion, myocardial infarcts were significantly smaller than those seen in animals reperfused after 24 to 72 hours of occlusion (4%, 14%, 20% and 21%, respectively). Thus, the effectiveness of any reperfusion procedure depends on its early institution when the coronary vascular bed has minimal change in functional capacity and the size of the infarct can still be reduced.
Zusammenfassung
Die hyperämische Reaktion der Koronararterien wurde in 24 unbetäubten Hunden nach Koronarverschluß von verschiedener Dauer und während Wiederdurchblutung der Kranzarterien gemessen. Nach 2stündigem Verschluß ergaben sich keine bedeutsamen Veränderungen der funktionellen Kapazität, bewiesen anhand unveränderter, reaktiver Höchsthyperämie, reaktiver Hyperämiefluß und “repayment of flow debt”. Nach 6stündigem Verschluß waren diese Reaktionen nach Wiederdurchblutung beeinträchtigt und blieben bis zu 5 Tagen erniedrigt. In den nach 2 bis 6 Stunden wiederdurchbluteten Tieren waren die Herzinfarkte wesentlich kleiner als bei Tieren, die 24 bis 72 Stunden nach Verschluß wiederdurchblutet wurden (4%, 14%, 20% und 21%, entsprechend). Die Wirksamkeit einer Wiederdurchblutung hängt demnach von einem frühen Eingriff ab, wenn das Koronargefäßnetz geringe Veränderungen in funktioneller Kapazität aufweist und wenn die Ausdehnung des Infarkts noch verkleinert werden kann.
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Bloor, C.M., White, F.C. Coronary artery reperfusion: Effects of occlusion duration on reactive hyperemia responses. Basic Res Cardiol 70, 148–158 (1975). https://doi.org/10.1007/BF01905616
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DOI: https://doi.org/10.1007/BF01905616