Features of coronary vessels may predict MI days before onset
A recent study suggests that features of the coronary vasculature, as detected on angiography, can predict the occurrence and timing of infarcts.
There is a delay of several days between thrombi or plaque rupture and onset of acute myocardial infarction (AMI), a Japanese study published in 24 October Circulation suggests. In the study, investigators from Gifu University School of Medicine studied 20 patients who had coronary angiograms performed within one week before AMI and 20 controls who had coronary angiograms performed between six and 18 months before AMI. The two groups did not differ significantly in any relevant baseline parameters. Angiographic analysis revealed that infarct-related coronary segments (IRCS) three days before AMI tended to have a significant stenosis of >50% and Ambrose's type II eccentric lesions — an indicator of plaque rupture and/or thrombi. Typical features at one year before AMI were mild stenosis of <50% with rare Ambrose's type II eccentric lesions, plus multiple irregularities. Analysis of subgroups according to the type of infarction — Q-wave infarction, non-Q-wave infarction, preceding effort angina within one month before AMI or no preceding effort angina — yielded similar results.
The current study, although far from conclusive, suggests that features of the coronary vasculature, as detected on angiography, can predict the occurrence (and timing) of infarcts. The presence of significant (>50%) stenoses and Ambrose's lesions are linked with AMI onset within three days, whereas a smooth vessel wall and sparse Ambrose's lesions tend to suggest AMI will not occur for one year.
This concept offers an insight into the mechanism and prevention of AMI, Ojio et al write. As there is a delay of at least three days between plaque rupture and/or thrombi, this suggests that "PTCA may be useful for the prevention of the onset of AMI in patients both with and without angina when the irregular vessel walls are observed." Further, they suggest that Ambrose's type II eccentric lesions are probably a predictor of recent MI, and say further investigation is warranted.