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[Activation of hemostasis and perioperative ischemia]
1Departamento de Anestesiología. German Heart Center, Munich, Germany.
Insights
Perioperative myocardial ischemia prevention requires a shift from solely reducing oxygen demand. New evidence suggests focusing on preventing thrombotic events and hypercoagulability is key for reducing cardiac events during surgery.
Area of Science:
- Anesthesiology and Cardiology
- Cardiovascular Research
- Perioperative Medicine
Background:
- Traditional anesthetic techniques focus on reducing myocardial oxygen demand to prevent perioperative ischemia.
- Cardiologists view myocardial infarction as a thrombotic event, independent of oxygen demand.
- Existing explanations for perioperative cardiac morbidity are insufficient.
Purpose of the Study:
- To challenge the traditional view of perioperative myocardial ischemia.
- To explore the role of thrombotic events and hypercoagulability in perioperative cardiac morbidity.
- To suggest alternative strategies for preventing perioperative myocardial infarction.
Main Methods:
- Review of existing data and concepts in perioperative cardiac care.
- Analysis of the relationship between oxygen supply/demand and thrombotic events.
- Examination of the role of procoagulants and hypercoagulability.
Main Results:
- Perioperative myocardial infarction is often a thrombotic event, not solely due to increased oxygen demand.
- Transient thrombotic occlusion or embolization can cause ischemia unrelated to demand.
- Hypercoagulability appears to be a significant factor in thrombotic events during surgery.
Conclusions:
- Anesthetic strategies should consider preventing atherosclerotic plaque rupture and monitoring coagulation changes.
- Focusing on hypercoagulability may be more effective in preventing perioperative myocardial infarction.
- A paradigm shift towards understanding thrombotic mechanisms is needed in perioperative cardiac care.
Abstract:
The prevention of perioperative myocardial ischemia is one of the cornerstones of anesthetic techniques. From the perspective of anesthesiologists, the traditional relation between oxygen supply and demand is improved mainly by reducing demand. Cardiologists, however, look at the problem from the other side of the equation. For the cardiologist, myocardial infarction is an entirely thrombotic event caused by changes in procoagulants, regardless of increased demand for oxygen. It is conceivable that signs of perioperative myocardial ischemia, which are related to increased oxygen demand, are equivalent to stable angina. Rarely do they cause myocardial infarction. However, transient occlusion or embolization from an unstable plaque can cause ischemia unrelated to increased demand. Cardiac morbidity during the perioperative period is insufficiently explained by the traditional concept of increased myocardial oxygen demand during surgery. On the contrary, evidence suggests that infarction depends on changes in oxygen supply secondary to transient or permanent episodes of thrombotic vascular occlusion. Our data suggest that these thrombotic events are dependent on hypercoagulability. It may be that anesthesiologists should focus on preventing rupture of the atherosclerotic plaque or on examining changes in coagulation, given that such events might facilitate the appearance of thrombosis in coronary arteries with unstable plaques.