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Early infarct artery collateral flow does not improve long-term survival following thrombolytic therapy for acute
J C Nicolau1, P R Nogueira, M A Pinto
1Heart Institute, Faculty of Medicine, University of São Paulo, Brazil. corjnicolau@incor4.incor.usp.br
Insights
Good coronary collateral flow in acute myocardial infarction (AMI) patients treated with thrombolysis is linked to worse long-term survival. Adequate anterograde flow, however, improves prognosis, suggesting residual ischemia may be a factor.
Area of Science:
- Cardiology
- Cardiovascular Research
- Interventional Cardiology
Background:
- Acutely developed collaterals can prevent acute myocardial infarction (AMI) during total coronary occlusion.
- Long-term prognosis related to coronary collateral circulation in AMI patients remains controversial.
Purpose of the Study:
- To analyze the prognostic role of collateral flow and anterograde flow in patients with AMI treated with thrombolytic therapy.
- To investigate the long-term survival outcomes based on coronary flow degrees.
Main Methods:
- Prospective follow-up of 422 AMI patients treated with intravenous streptokinase for up to 8 years.
- Assessment of collateral flow and anterograde flow (degrees 0-3) via coronary arteriography.
- Statistical analysis including censored regression and Cox multivariate analysis.
Main Results:
- Patients with collateral flow grade 3 had lower survival rates (66%) compared to those with flow <3 (85%).
- Patients with anterograde flow grade 3 had higher survival rates (89%) compared to those with flow <3 (80%).
- Censored regression and Cox analysis revealed negative correlation between collateral flow and survival, and positive correlation between anterograde flow and survival.
Conclusions:
- Adequate coronary collateral circulation in AMI patients treated with streptokinase is associated with a worse prognosis.
- This poorer outcome may be due to residual myocardial ischemia, highlighting the benefit of restoring anterograde blood flow.
- Coronary revascularization (angioplasty or surgery) may improve outcomes by minimizing myocardium at risk.
Abstract:
It is known that acutely developed collaterals can prevent the onset of acute myocardial infarction (AMI) in the presence of a total coronary occlusion. However, there still is controversy concerning long-term follow-up of coronary collateral circulation to the infarct-related artery. In this study we analyze the prognostic role of collateral flow (degrees 0 to 3) as well as anterograde flow (degrees 0 to 3) in patients with AMI treated with thrombolytic therapy. Four hundred twenty-two patients (median age 57 years, 355 men) with AMI were treated with intravenous streptokinase and followed prospectively for up to 8 years. At the end of the study period, patients with collateral coronary flow 3 (n = 30) and those with flow <3 (n = 392) at in-hospital coronary arteriography had survival rates of 66% and 85%, respectively (p <0.12). Meanwhile, patients with coronary anterograde flow 3 (n = 189) and those with flow <3 (n = 233) had survival rates of 89% and 80%, respectively (p <0.04). By censored regression analysis, a negative correlation was found between coronary collateral flow degree and survival (p = 0.0498) and, inversely, a positive correlation was found between coronary anterograde flow degree and survival (p = 0.0053). By Cox multivariate analysis, the following variables showed significant correlations with long-term survival: global left ventricular ejection fraction (p = 0.0003), anterograde flow degree (p = 0.0006), collateral flow degree (negative correlation, p = 0.0179), and medical treatment (negative correlation, p = 0.0464). Thus, patients treated with intravenous streptokinase during AMI and with adequate coronary collateral circulation had a worse prognosis than those who developed adequate anterograde flow, probably because of residual myocardial ischemia. Such patients may benefit from coronary revascularization (angioplasty or surgery) to restore anterograde blood flow and minimize myocardium at risk.