Triphenyltetrazolium chloride has been used to detect irreversibly damaged tissue after regional
ischemia and reperfusion. We used this staining technique in our studies of
myocardial ischemia and reperfusion and found that a transmural
triphenyltetrazolium chloride nonstaining pattern is not an accurate predictor of myocardial
necrosis: functional recovery occurs despite nonstaining. Mongrel dogs (n = 91) were anesthetized and made ischemic by
ligation of the left anterior descending coronary artery. Regional myocardial function was assessed by means of ultrasonic crystals. Following 2, 4, or 6 hours of
ischemia, the
ligature was removed, and each heart was reperfused either in the working state or during total bypass with either normal blood or substrate-enriched blood
cardioplegic solution of differing composition. The hearts were then removed and incubated in
triphenyltetrazolium chloride at 37 degrees C for 20 to 40 minutes. The pattern of nonstaining in the area at risk varied from patchy subendocardial, to confluent subendocardial, to transmural and did not correlate with the recovery of regional contraction following
ischemia. Mitochondrial ultrastructure was altered minimally in nonstained muscle, which regained contractile function after 6 hours of
ischemia. Fifty-two of sixty-five hearts (80%) showing a transmural nonstaining pattern in the area of ultrasonic crystal placement recovered the capacity to shorten systolically immediately after controlled reperfusion during total vented bypass. These results show that the
triphenyltetrazolium chloride staining method does not predict myocardial
necrosis and that appropriate reperfusion following 2 to 6 hours of
ischemia will result in recovery of myocardial shortening despite transmural nonstaining.