Effects of preinfarction angina on myocardial injury in patients with acute myocardial infarction: a study with resting 123I-BMIPP and 201T1 myocardial SPECT.
METHODS
Recent studies have suggested that patients with preinfarction angina have smaller infarcts and a better in-hospital outcome than those without angina. The mechanisms responsible for limitation of infarct size in the presence of preinfarction angina are unclear. We examined the effects of preinfarction angina on myocardial injury in patients with the first acute myocardial infarction with resting 123I-15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) 201TI myocardial scanning performed within 1 mo of infarction.


RESULTS
Of 136 patients tested, 48 (35%) had preinfarction angina within 72 h before infarction, whereas 88 (65%) did not. BMIPP and 201TI defects were scored in 9 segments of the left ventricle (0 = normal, 1 = mild defect, 2 = moderate defect, 3 = severe defect, and 4 = no uptake). The total defect score was defined as the sum of the defect scores. There was no significant difference in percentage diameters of stenoses of infarct-related arteries, collateral circulation, total defect scores for BMIPP, or 201TI between the groups with and without preinfarction angina. However, the ratio of total defect score for 201TI to that for BMIPP was significantly smaller for patients with than for those without preinfarction angina (0.64 +/- 0.21 versus 0.74 +/- 0.25, respectively; P = 0.007).


CONCLUSIONS
Preinfarction angina did not affect the areas at risk in acute myocardial infarction, as shown by BMIPP defect, but decreased necrotic myocardium in the areas at risk, as shown by 201TI defect, and increased metabolically damaged but viable myocardium, as shown by BMIPP and 201TI mismatch through unidentified mechanisms other than collateral circulation (e.g., ischemic preconditioning).
Yamagishi
H
H
First Department of Internal Medicine, Osaka City University Medical School, Osaka, Japan.
Akioka
K
K
Hirata
K
K
Sakanoue
Y
Y
Toda
I
I
Yoshiyama
M
M
Teragaki
M
M
Takeuchi
K
K
Yoshikawa
J
J
Ochi
H
H
D000789:Angina, Unstable / Q000150:complications*; D017023:Coronary Angiography; D003402:Creatine Kinase / Q000097:blood; D005227:Fatty Acids; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D007457:Iodine Radioisotopes; D007462:Iodobenzenes; D007527:Isoenzymes; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications / Q000175:diagnosis / Q000000981:diagnostic imaging*; D019275:Radiopharmaceuticals; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon
D005227:Fatty Acids; D007457:Iodine Radioisotopes; D007462:Iodobenzenes; D007527:Isoenzymes; D019275:Radiopharmaceuticals; D013794:Thallium Radioisotopes; C049338:iodofiltic acid; D003402:Creatine Kinase