Computed tomography evaluation of regional increases in microvascular permeability after reperfusion of locally ischemic myocardium in intact pigs

Rationale and Objectives.: I evaluated how well fast computed tomography (CT) scanning could quantify altered myocardial microvascular function resulting from transient ischemia and subsequent reperfusion. Methods.: A major epicardial coronary artery of anesthetized pigs was occluded for either 0, 15, 30, 60, or 120 min. Fast X-ray CT scan sequences were performed before and during occlusion and 30, 60, and 90 min after onset of subsequent reperfusion. Regional myocardial perfusion, intramyocardial blood volume, and myocardial microcirculatory permeability-surface area product were estimated from the CT scan sequences. Results.: With the increasing duration of ischemia, the permeability-surface area product remained unchanged during reperfusion (p > .05), but an index of myocardial microvascular permeability increased with the progressive duration of ischemia and of reperfusion (p > .05). Conclusion.: These CT-based findings are consistent with published, more invasive demonstrations that capillary permeability is increased during postischemic reperfusion in proportion to the duration of the preceding ischemia.