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Coronary arteriographic findings soon after non-Q-wave myocardial infarction
Insights
Complete coronary artery occlusion is rare early in non-Q-wave myocardial infarction but increases over days. This suggests non-Q-wave infarction may stem from limited blood supply, impacting myocardial oxygen balance.
Area of Science:
- Cardiology
- Interventional Cardiology
- Myocardial Infarction Research
Background:
- Complete occlusion of the infarct-related coronary artery is common in Q-wave myocardial infarction.
- Understanding coronary artery status in non-Q-wave myocardial infarction is crucial for patient management.
Purpose of the Study:
- To investigate the frequency of total coronary occlusion and collateral vessels in non-Q-wave myocardial infarction patients within one week of symptom onset.
- To compare early coronary artery findings in non-Q-wave infarction with those typically seen in Q-wave infarction.
Main Methods:
- A cross-sectional study involving 341 patients with non-Q-wave myocardial infarction.
- Coronary arteriography performed within seven days of peak symptoms, categorized into three time groups: <24 hours, 24-72 hours, and 72 hours-7 days.
- Analysis of total occlusion, subtotal occlusion (≥90% stenosis), and visible collateral vessels.
Main Results:
- Total occlusion of the infarct-related vessel was infrequent initially (26%) but increased significantly over time (up to 42%, P<0.05).
- Visible collateral vessels also increased in frequency over the study period (27% to 42%, P<0.05).
- Subtotal occlusion frequency decreased inversely with time (34% to 18%, P<0.05).
Conclusions:
- Unlike Q-wave infarction, total coronary occlusion is uncommon early in non-Q-wave myocardial infarction.
- The findings suggest non-Q-wave infarction may result from a compromised but still present blood supply, leading to myocardial oxygen imbalance.
- Coronary artery patency and collateralization evolve in the early days following non-Q-wave myocardial infarction.
Abstract:
Complete occlusion of the infarct-related coronary artery is a frequent finding soon after Q-wave (transmural) myocardial infarction. We performed coronary arteriography to study the frequency of total coronary occlusion and of angiographically visible collateral vessels in 341 patients within one week of non-Q-wave myocardial infarction. In this cross-sectional study, 192, 94, and 55 patients underwent coronary arteriography within 24 hours of peak symptoms, between 24 and 72 hours after peak symptoms, and between 72 hours and seven days after peak symptoms, respectively. In the three groups, total occlusion of the infarct-related vessel was found in 26 percent (49 of 192), 37 percent (35 of 94), and 42 percent (23 of 55) of the patients, respectively (P less than 0.05). The presence of visible collateral vessels increased in parallel: 27 percent (52 of 192), 34 percent (32 of 94), and 42 percent (23 of 55), respectively (P less than 0.05). The frequency of subtotal occlusion (i.e., greater than or equal to 90 percent stenosis) decreased inversely: 34 percent (65 of 192), 25.5 percent (24 of 94), and 18 percent (10 of 55), respectively (P less than 0.05). Thus, in contrast to Q-wave infarction, total coronary occlusion of the infarct-related vessel is infrequently observed in the early hours of non-Q-wave infarction, but it increases moderately in frequency over the next several days. These cross-sectional data suggest that non-Q-wave infarction may be related to a preserved but marginal blood supply, which sufficiently disrupts the relation between the supply of and the demand for myocardial oxygen to cause tissue necrosis.