Introduction
Reducing cardiovascular risk is important in any non-cardiac surgery to ensure no complications occur during the intraoperative and postoperative period. The safety and well-being of the patient are established in patients with pre-existing cardiovascular conditions. Major surgery happens in about 5 percent of the population worldwide, accounting for up to more than 300 million patients. The risk of cardiovascular morbidity and mortality in patients undergoing non-cardiac surgery is significant, and there is a need to evaluate the risks. Cardiac complications like myocardial infarction and congestive heart failure still top the list of cardiovascular risks in surgeries.
What Is a Non-cardiac Surgery?
Non-cardiac surgery refers to surgeries performed in organs excluding the heart. It can be wide-ranging from orthopedic, abdominal, neuro surgeries, urologic surgeries, etc. Though the primary focus is on the organs affected, it is mandatory to evaluate the cardiovascular risks before performing any surgeries.
What Cardiovascular Risks Can Be Expected in a Noncardiac Surgery?
Some of the cardiovascular risks that may occur in a non-cardiac surgery include:
- Heart Attack: Heart attack or myocardial infarction can be triggered in patients just by the stress of surgery. It is especially evident in patients with coronary artery disease. Hemodynamic changes, such as reduced oxygen supply to the heart and blood pressure fluctuations, can precipitate myocardial ischemia.
- Arrhythmia: Disruption of the normal electrical conduction of the heart can occur due to surgery. This can result in arrhythmia, including atrial fibrillation or ventricular arrhythmias. These abnormal heart rhythms can cause detrimental effects on heart function and increase the risk of complications.
- Heart Failure: Hemodynamic changes, surgical stress, and fluid shifts will worsen heart failure in those patients with a pre-existing cardiovascular condition. The heart will find it difficult to pump blood, leading to shortness of breath, decreased exercise tolerance, and fluid retention.
- Pulmonary Embolism: The risk of blood clot formation is increased during the surgery and also during the postoperative period. This is primarily due to the immobility of the patient, leading to a heightened risk of developing deep vein thrombosis (blood clots forming in the legs) that has the potential to travel to the lungs, causing pulmonary embolism. Pulmonary embolism, in turn, increases the cardiovascular strain, leading to impaired oxygenation.
- Hypertensive Crisis: Surgical stress can induce a significant elevation in blood pressure that will lead to a hypertensive crisis. This can trigger risks to the heart, blood vessels, and other vital organs.
- Perioperative Bleeding: Depending on the type and nature of the procedure, the patients may be susceptible to having bleeding intra and post-operatively. Excess blood loss will lead to hemodynamic instability and subsequent cardiovascular complications.
- Fluid and Electrolyte Imbalance: Perioperative fluid shifts and alterations in the electrolyte levels can influence cardiovascular function. Therefore, it is mandatory to avoid both excessive fluid administration and dehydration in order to maintain appropriate hemodynamics.
What Are the Guidelines to Follow for Minimizing Cardiovascular Risk in Noncardiac Surgery?
1. Pre-operative Assessment: A thorough preoperative assessment that includes medical history, complete physical examination, patient’s cardiovascular health, and other relevant investigations such as electrocardiogram, echocardiography, and stress testing should be done prior to the surgery. Early identification of potential risk factors such as obesity, hyperglycemia, high blood pressure, etc should be identified. If any modifiable risks are present, they should be altered.
2. Risk Stratification: The patient’s risk of getting cardiovascular events on the table should be assessed. They are to be validated based on standard risk indices such as the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) and the Revised Cardiac Risk Index (RCRI). This will help enable physicians to identify patients at high risk, and early intervention can be done.
3. Collaboration Between Surgeons and Cardiologists: A strong collaboration between surgeons and cardiologists is encouraged to facilitate discussions about the cardiovascular risk of patients and perioperative management strategy. It is advised to seek cardiology consultation for patients with high-risk cardiovascular conditions.
4. Medication Management: Medications should be optimized before surgery. Uninterrupted use of necessary medications such as beta-blockers, statins, antiplatelet agents, and hypertensive drugs throughout the perioperative period unless there are specific contraindications. Evaluation of potential risks and benefits of continuing or discontinuing anticoagulant therapy cautiously.
5. Glucose Control: Regularly monitor and ensure proper maintenance of glucose levels within the recommended range throughout the perioperative period, especially in patients with diabetes. It is important to prevent hyperglycemia as it increases the risk of adverse cardiovascular events.
6. Blood Pressure Control: Maintaining blood pressure within the desirable range is important throughout the perioperative period. In patients with hypertension, it is important to continue using antihypertensive medications and, if needed, include additional measures like invasive monitoring or dosage adjustment for managing blood pressure effectively.
7. Smoking Cessation: Encourage patients to cease smoking before surgery, as it is a significant cardiovascular risk factor. Provide appropriate counseling, nicotine replacement therapy, and pharmacotherapy to support smoking cessation efforts.
8. Perioperative Fluid Management: Optimize the management of fluids during the perioperative period and intraoperative period to maintain proper fluid balance, as excessive fluid administration or dehydration can have adverse effects on cardiovascular function. Consider invasive monitoring and goal-directed fluid therapy for patients at high risk.
9. Postoperative Monitoring: Monitoring the patients closely during the postoperative period for any cardiovascular complications, such as myocardial infarction, heart failure, arrhythmias, or pulmonary embolism. Swift investigation and addressing any concerning findings.
10. Rehabilitation and Secondary Prevention: Implementation of a comprehensive cardiac rehabilitation program for patients who are at a high risk of cardiovascular events following noncardiac surgery. This program should include medication optimization, physical activity, dietary modifications, and management of risk factors to reduce the likelihood of future cardiovascular incidents.
Conclusion
It is important to emphasize that these guidelines are general recommendations, and the mitigation of cardiovascular risk in noncardiac surgery differs based on patient factors and each patient’s needs. A multidisciplinary team involving anesthesiologists, surgeons, cardiologists, and primary care physicians should coordinate amongst themselves to provide optimal care and effectively decrease the cardiovascular risk in patients undergoing noncardiac surgeries.
