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Postconditioning with Lactate-enriched Blood for Cardioprotection in ST-segment Elevation Myocardial Infarction
Published on: May 28, 2019
Cardioprotective Role of Coronary Collaterals in the Development of Intramyocardial Hemorrhage in ST-Segment
Keyur P Vora1, Ankur Kalra2, Khalid Youssef3
1Medical Imaging Research Institute, Cardiovascular Imaging Research Center, Indiana University School of Medicine, Indianapolis, Indiana, USA; Synergy Cardiovascular Research Center, Synergy Superspecialty Hospital, Rajkot, Gujarat, India; Upstate Medical University, State University of New York, Syracuse, New York, USA.
Insights
The extent of coronary collaterals significantly impacts intramyocardial hemorrhage (IMH) in ST-segment elevation myocardial infarction (STEMI) patients. Identifying patients with poor collaterals can help predict and manage infarct expansion.
Area of Science:
- Cardiology
- Interventional Cardiology
- Cardiovascular Imaging
Background:
- Intramyocardial hemorrhage (IMH) is a significant predictor of adverse outcomes in ST-elevation myocardial infarction (STEMI) patients, impacting myocardial salvage and infarct size.
- IMH is observed in a substantial proportion of STEMI patients undergoing revascularization, highlighting its clinical relevance.
Purpose of the Study:
- To investigate the relationship between the presence and extent of coronary collateral circulation and the development of IMH in STEMI patients.
- To determine if coronary collateral status influences infarct size and microvascular obstruction post-percutaneous coronary intervention (PCI).
Main Methods:
- The MIRON-CL trial enrolled 294 STEMI patients undergoing primary PCI.
- Coronary collateral status was assessed using Rentrop grades via pre-PCI angiography.
- Cardiac magnetic resonance imaging (CMR) was used 3 days post-PCI to quantify T2 edema (area at risk), T2* (IMH), and late gadolinium enhancement (infarct size).
Main Results:
- Patients with no coronary collaterals (Grade 0) exhibited significantly higher IMH compared to those with collaterals (Grade I-III).
- Absence of collaterals was associated with a larger area at risk, larger infarct size, and increased microvascular obstruction post-PCI.
- Lack of collaterals independently predicted a higher risk of developing IMH (OR: 5.71).
Conclusions:
- Coronary collateral extent is a key determinant of IMH in STEMI patients after revascularization.
- Assessing collateral status can identify STEMI patients at high risk for infarct expansion.
- Further research into targeted therapies to reduce IMH and improve outcomes in high-risk patients is warranted.
Background:
Intramyocardial hemorrhage (IMH), evident in 40% of revascularized ST-segment elevation myocardial infarction (STEMI) patients, is a lethal determinant of MI size. IMH compromises myocardial salvage and drives major adverse cardiovascular events.
Objectives:
We sought to determine whether the presence and extent of coronary collaterals affect development of IMH in STEMI patients.
Methods:
The MIRON-CL trial (NCT05898425) enrolled 294 consecutive STEMI patients reperfused via primary percutaneous coronary intervention (PCI). All underwent pre-PCI angiography to determine Rentrop collateral grades (0: none; III: complete). Three days post-PCI cardiac magnetic resonance imaging quantified myocardial area at risk (T2 edema), IMH (T2∗), and MI (late gadolinium enhancement).
Results:
Among 294 patients, 124 had IMH and 170 did not. Patients with no collaterals (CL-, Grade 0) had higher IMH (7.41% ± 5.33% left ventricle) than those with collaterals (CL+; Grade I: 5.23% ± 3.21%, II: 3.11% ± 2.78%, III: 2.05% ± 1.89%; P < 0.001). Total area at risk post-PCI was larger in CL- (37.62% ± 15.32% left ventricle) than in CL+ (21.48% ± 13.21%; P < 0.001). Absence of collaterals correlated with larger MI (CL- 38.66% ± 14.63% vs CL+ 19.84% ± 13.72%; P < 0.001) and higher microvascular obstruction (CL- 8.07% ± 6.60% vs CL+ 2.17% ± 2.35%; P < 0.001). Patients without collaterals had a higher adjusted risk of IMH (OR: 5.71; 95% CI: 3.16-10.33; P < 0.0001).
Conclusions:
Extent of coronary collaterals is a determinant of IMH in revascularized STEMI. Since IMH is known to drive post-PCI infarct expansion, determination of collateral status has the potential to identify patients at high risk of infarct expansion. For these high-risk patients, novel targeted therapies to reduce IMH, limit post-MI infarct expansion, and improve outcomes should be further explored.
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