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Relationship between the preexistent coronary collateral circulation and successful intracoronary thrombolysis for
1Second Department of Internal Medicine, Toyama Medical and Pharmaceutical University, Japan.
Insights
Good coronary collateral circulation hinders successful intracoronary thrombolysis for acute myocardial infarction. Poor or absent collaterals improve recanalization rates, suggesting stenosis severity impacts lytic therapy effectiveness.
Area of Science:
- Cardiology
- Interventional Cardiology
- Vascular Biology
Background:
- Coronary collateral circulation plays a vital role in myocardial perfusion during acute coronary events.
- The impact of collateral status on the efficacy of acute myocardial infarction treatments remains an area of investigation.
Purpose of the Study:
- To investigate the influence of coronary collateral circulation on recanalization rates achieved with intracoronary thrombolysis in patients with acute myocardial infarction.
Main Methods:
- A cohort of 85 patients with acute myocardial infarction and completely occluded infarct-related arteries received intracoronary thrombolysis with high-dose urokinase.
- Patients were categorized into two groups based on angiographically assessed collateral circulation: good (Group A) versus poor/absent (Group B).
- Successful recanalization was defined as a residual stenosis of ≤90%.
Main Results:
- Successful recanalization occurred in only 28% of patients with good collateral circulation (Group A) compared to 60% in those with poor/absent collaterals (Group B) (p < 0.05).
- Antegrade flow post-thrombolysis was observed in 67% of Group A and 84% of Group B patients (p = NS).
- Good collateral circulation was associated with high-grade stenosis, which inversely correlated with thrombolytic therapy efficacy.
Conclusions:
- Coronary collateral circulation is inversely related to the success rate of intracoronary thrombolytic therapy.
- The effectiveness of thrombolytic therapy in acute myocardial infarction appears to be influenced by the severity of underlying coronary artery stenosis.
- Findings suggest that the presence of collaterals may indicate more severe stenosis, impacting treatment outcomes.
Abstract:
The purpose of this study was to evaluate whether the existence of coronary collateral circulation influences recanalization rates of intracoronary thrombolysis. The study population consisted of 85 consecutive patients undergoing intracoronary thrombolysis within 6 hours after the onset of the first acute myocardial infarction, all of whom had a complete occlusion of the infarct-related coronary artery. Intracoronary thrombolysis with high-dose urokinase (960,000 IU) was attempted at a rate of 24,000 IU/min. Of 18 patients (group A) who had good angiographic collateral circulation to the area perfused by the infarct-related coronary artery, the obstructed artery was recanalized to a residual luminal diameter stenosis of less than or equal to 90% (successful recanalization) in only five (28%). In contrast, of 67 patients (group B) with poor or no collateral circulation, recanalization was successful in 40 (60%) (p less than 0.05). Antegrade flow of infarct-related arteries was observed following thrombolysis in 12 (67%) of 18 group A patients and in 56 (84%) of 67 group B patients (p = NS). It was concluded that (1) the presence of collaterals correlates with the presence of high-grade stenosis; (2) the presence of collaterals correlates with the presence of high-grade stenosis; (2) the presence of collaterals is inversely related to the efficacy of thrombolytic therapy; and (3) the difference in successful recanalization rates observed between the two groups probably reflects the impact of underlying stenosis severity on the effectiveness of lytic therapy.