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A simple classification of the risk in cardiac surgery
Insights
A new cardiac surgery risk classification accurately predicts patient outcomes. This tool helps anaesthesiologists assess cardiac surgery risk, stratifying patients into normal, increased, and high-risk groups based on specific factors.
Area of Science:
- Cardiology
- Anesthesiology
- Surgical Risk Assessment
Background:
- Cardiac surgery carries inherent risks.
- Accurate preoperative risk stratification is crucial for patient management and outcomes.
- Existing risk assessment tools may require refinement for specific patient populations.
Purpose of the Study:
- To introduce and validate a new risk classification system for patients undergoing cardiac surgery.
- To assess the reliability of this classification in predicting operative morbidity and mortality.
- To evaluate its utility in preoperative patient assessment and for educational purposes.
Main Methods:
- Development of a risk classification based on eight factors: left ventricular function, heart failure, angina/myocardial infarction, age, obesity, reoperation, emergency surgery, and systemic disturbances.
- Prospective study of 500 consecutive open-heart surgery patients categorized as normal, increased, or high risk.
- Retrospective analysis of 50 deaths following cardiac surgery using the new classification.
Main Results:
- Normal risk patients (50%) had a 0.4% mortality rate.
- Increased risk patients (32%) had a 3.1% mortality rate.
- High risk patients (18%) experienced a 12.2% mortality rate.
- Retrospective analysis showed 58% of deaths occurred in the high-risk group.
Conclusions:
- The new risk classification system is a reliable and effective tool for preoperative assessment in cardiac surgery.
- It accurately correlates with operative mortality, aiding in patient management.
- The classification serves as a valuable educational aid for anaesthesiologists.
Abstract:
A new risk classification for patients undergoing cardiac surgery has been used for the last two years by the anaesthesiologists of the Montreal Heart Institute. The following factors known to be associated with a greater operative morbidity and mortality were selected: (1) poor left ventricular function, (2) congestive heart failure, (3) unstable angina or recent (less than 6 weeks) myocardial infarction, (4) age over 65 years, (5) severe obesity (Body Mass Index greater than 30), (6) reoperation, (7) emergency surgery, (8) other significant or uncontrolled systemic disturbances. Patients with none of the above factors were classified as normal risks; those presenting with one of those selected factors were classified as increased risks, and those with more than one factor were said to carry a high risk. In a prospective study of 500 consecutive open-heart surgery patients classified according to this method, we found that the operated population at normal risk (50 per cent of cases) had a mortality of 0.4 per cent, the patient group with increased risk (32 per cent of cases) had a mortality of 3.1 per cent, and the high risk group (18 per cent of cases) had a 12.2 per cent mortality. Furthermore, 50 deaths following open-heart surgery were assessed retrospectively using the classification; 58 per cent of these patients were classified as high risk, 34 per cent had an increased risk, and only eight per cent were found to be in the normal risk group. Thus, this new risk classification has proven to be a reliable and useful tool for preoperative assessment of patients undergoing open-heart surgery and for teaching purposes.