# Study Guide: 2024 Perioperative Cardiovascular Management for Noncardiac Surgery This study guide is designed to synthesize the clinical practice guidelines for the perioperative cardiovascular evaluation and management of adult patients undergoing noncardiac surgery (NCS). It focuses on risk assessment, diagnostic testing, and the management of specific cardiovascular comorbidities. --- ## Section 1: Key Concepts Summary ### 1. The Stepwise Approach The fundamental framework for perioperative care is a stepwise assessment. Clinicians must first determine the urgency of the surgery (Emergency, Urgent, Time-sensitive, or Elective) and then estimate the risk of Major Adverse Cardiovascular Events (MACE). If the risk is elevated (≥1%), further evaluation of functional capacity and potential biomarkers is warranted. ### 2. Defining Surgical Risk and Timing * **Low Risk:** Predicted MACE <1%. * **Elevated Risk:** Predicted MACE ≥1% (includes intermediate and high-risk procedures). * **Emergency:** Immediate threat to life or limb (<2 hours). * **Urgent:** Threat to life or limb (2–24 hours). * **Time-sensitive:** Delayable up to 3 months without negatively impacting outcomes. * **Elective:** Can be delayed for complete evaluation and management. ### 3. Functional Capacity and Frailty Functional capacity is a primary predictor of perioperative outcomes. It is measured in Metabolic Equivalents (METs), with **4 METs** serving as the threshold for poor capacity. The **Duke Activity Status Index (DASI)** is a validated 12-item tool used to quantify this. Frailty is an independent risk factor for complications and should be assessed in patients ≥65 years old using tools like the Clinical Frailty Scale or the Fried phenotype. ### 4. Judicious Diagnostic Testing * **12-Lead ECG:** Not recommended for asymptomatic patients in low-risk surgery. It is reasonable for those with known cardiovascular disease (CVD) or symptoms undergoing elevated-risk surgery. * **Stress Testing:** Should only be performed if the results would change management independent of the surgery. It is generally reserved for patients with poor or unknown functional capacity and elevated risk. * **Biomarkers:** BNP/NT-proBNP and cardiac troponin (cTn) can supplement risk evaluation in elevated-risk patients but should not be used routinely in low-risk cases. ### 5. Critical Medication Management * **SGLT2 Inhibitors:** Must be discontinued **3 to 4 days** before surgery to mitigate the risk of euglycemic ketoacidosis. * **GDMT (Guideline-Directed Management and Therapy):** Generally, medications for heart failure and hypertension should be continued, though ACEi/ARBs may be held depending on the risk of intraoperative hypotension. * **Beta Blockers:** Should not be abruptly discontinued if taken chronically to avoid rebound hypertension. --- ## Section 2: Short-Answer Practice Questions **1. What is the intraoperative Mean Arterial Pressure (MAP) threshold recommended to reduce the risk of myocardial injury?** *Answer:* Maintaining an intraoperative MAP ≥60 to 65 mm Hg (or SBP ≥90 mm Hg) is recommended. **2. Which specific patient population requires a preoperative consultation with an Adult Congenital Heart Disease (ACHD) specialist?** *Answer:* Patients with intermediate- to elevated-risk congenital heart disease lesions undergoing elective NCS. **3. Why is routine preoperative coronary revascularization "not recommended" for patients with stable chronic coronary disease (CCD)?** *Answer:* Evidence (such as the CARP trial) shows that routine revascularization does not reduce the 30-day or 1-year rates of death or MI compared to medical therapy alone in stable patients. **4. What DASI score is considered a threshold for increased odds of 30-day death or MI?** *Answer:* A DASI score ≤34 is associated with increased perioperative risk. **5. In patients with Hypertrophic Cardiomyopathy (HCM), what types of agents should be avoided during the management of hypotension?** *Answer:* Positive inotropic agents and beta-agonists should be avoided as they can aggravate left ventricular outflow tract (LVOT) obstruction. Alpha-agonists (e.g., phenylephrine) are preferred. **6. What are the three primary components used to define "precapillary" Pulmonary Hypertension (PH) via right heart catheterization?** *Answer:* Mean pulmonary artery pressure >20 mm Hg, pulmonary artery wedge pressure ≤15 mm Hg, and pulmonary vascular resistance >2 Wood units. --- ## Section 3: Essay Prompts for Deeper Exploration **1. The "Less is More" Philosophy in Preoperative Testing** Discuss the rationale behind the 2024 guidelines' recommendation against routine ECGs and stress tests for low-risk surgeries. Explain the potential harms of over-testing, including the concept of "downstream" testing and surgical delays, and contrast this with the specific scenarios where advanced imaging like CCTA might be considered. **2. Managing the Complex Heart Failure Patient** Analyze the perioperative challenges of a patient with heart failure. Your essay should address the importance of continuing GDMT, the specific timing and risks associated with SGLT2 inhibitors, and how the severity of left ventricular ejection fraction (LVEF) correlates with 90-day mortality rates. **3. Multidisciplinary Team-Based Care in Modern Perioperative Medicine** Evaluate the role of "team-based care" for patients with complex conditions such as LVADs, PH, or ACHD. How does the coordination between surgeons, anesthesiologists, and cardiologists impact patient-centered goals like "recovery at home," and what are the specific clinical advantages of specialized PH or ACHD centers? --- ## Section 4: Glossary of Important Terms | Term/Abbreviation | Definition | | :--- | :--- | | **ACHD** | Adult Congenital Heart Disease; survival of CHD patients into adulthood requiring specialized care. | | **ACS** | Acute Coronary Syndrome; includes STEMI, NSTEMI, and unstable angina. | | **CCTA** | Coronary Computed Tomography Angiography; non-invasive imaging to detect CAD and high-risk anatomy. | | **CPET** | Cardiopulmonary Exercise Testing; the gold standard for objective functional capacity assessment. | | **cTn** | Cardiac Troponin; a biomarker used to detect myocardial injury. | | **DASI** | Duke Activity Status Index; a self-reported tool to estimate functional capacity and METs. | | **Elevated Risk** | A predicted risk of MACE ≥1% based on patient and surgical factors. | | **FoCUS** | Focused Cardiac Ultrasound; a point-of-care ultrasound used for emergency hemodynamic evaluation. | | **GDMT** | Guideline-Directed Management and Therapy; the optimal medical strategy recommended by clinical guidelines. | | **HCM** | Hypertrophic Cardiomyopathy; an inherited heart muscle disorder often involving LVOT obstruction. | | **ICA** | Invasive Coronary Angiography; the gold standard for defining coronary anatomy. | | **MACE / MACCE** | Major Adverse Cardiovascular Events / Major Adverse Cardiac and Cerebral Events. | | **METs** | Metabolic Equivalents; a unit of oxygen consumption used to measure exercise intensity. | | **MINS** | Myocardial Injury after Noncardiac Surgery; a newly identified disease process with significant prognostic consequences. | | **RCRI** | Revised Cardiac Risk Index; a validated tool using six predictors to estimate major cardiac complications. | | **SGLT2i** | Sodium-Glucose Cotransporter-2 Inhibitors; medications for diabetes and heart failure that must be paused preoperatively. |