title: Influence of coronary venous retroinfusion and vasodilatation on regional myocardial blood flow measurement with microspheres. An analysis of 'microsphere loss' from ischaemic and reperfused porcine hearts.
abstract: The influence of coronary venous retroinfusion and a vasoselective calcium antagonist felodipine on the microsphere loss in a porcine model of myocardial ischaemia and reperfusion was studied. Sixteen open-chest pigs underwent 45 min of myocardial ischaemia induced by occlusion of the left anterior descending coronary artery followed by 4 h of reperfusion. Either felodipine (felo-retro group, 7 nmol kg-1, n = 6) or the corresponding amount of vehicle (vehicle-retro group, n = 5) was infused retrogradely into the coronary veins over 30 min, starting 5 min before reperfusion. In a third group, the same amount of felodipine was administered intravenously (felo-iv group, n = 5). Myocardial regional blood flow was measured with radiolabelled microspheres (phi = 15 microns) injected before ischaemia to investigate a possible loss during ischaemia. In the felo-retro group, the apparent blood flow in the ischaemic areas, expressed as a percentage of the corresponding values in the non-ischaemic areas (%-flow), were 73 +/- 15, 73 +/- 11 and 75 +/- 19 in the subendocardial, midmyocardial and subepicardial layers, respectively. The corresponding percentage flows were 64 +/- 11, 70 +/- 11 and 62 +/- 9 in the vehicle-retro group and 75 +/- 18, 77 +/- 15 and 76 +/- 11 in the felo-iv group. The differences between the groups were not statistically significant. It is concluded that in this open-chest preparation microsphere loss observed in the ischaemic and reperfused myocardium is not increased by coronary venous retroinfusion or by a concomitantly administered vasodilative agent like felodipine.
authors.affiliation: Department of Cardiology, Karolinska Hospital, Stockholm, Sweden.
authors.forename: Y
authors.initials: Y
authors.lastname: Haga
authors.forename: R
authors.initials: R
authors.lastname: Nordlander
authors.forename: P O
authors.initials: PO
authors.lastname: Sjöquist
authors.forename: L
authors.initials: L
authors.lastname: Rydén
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D001794:Blood Pressure; D005260:Female; D006339:Heart Rate; D008297:Male; D008863:Microspheres; D017202:Myocardial Ischemia / Q000503:physiopathology*; D015425:Myocardial Reperfusion; D014664:Vasodilation