What is the recommended approach for evaluating a patient's readiness for surgery, particularly for those with pre-existing medical conditions such as hypertension or diabetes?

Preoperative Surgery Clearance Evaluation

Primary Recommendation

For patients with pre-existing conditions like hypertension or diabetes undergoing noncardiac surgery, use a stepwise risk stratification approach: first assess urgency and active cardiac conditions, then estimate perioperative risk using the Revised Cardiac Risk Index combined with surgical risk, and finally determine functional capacity to guide the need for additional testing—proceeding directly to surgery when risk is low (<1% MACE) or functional capacity is adequate (≥4 METs). 1, 2

Step-by-Step Evaluation Algorithm

Step 1: Determine Urgency and Active Conditions

• Emergency surgery: Proceed immediately with limited evaluation focusing on vital signs, volume status, hematocrit, electrolytes, renal function, and ECG 2
• Urgent/elective surgery: Screen for unstable coronary syndromes, decompensated heart failure, significant arrhythmias, and severe valvular disease—delay surgery if any are present for stabilization 1, 2
• Patients with acute MI within 7 days or recent MI (7-30 days) require cardiology consultation before proceeding 1

Step 2: Risk Stratification Using Clinical Markers

Calculate perioperative cardiac risk using the Revised Cardiac Risk Index (RCRI), which includes: 1, 2, 3

• High-risk surgery (vascular, prolonged thoracic/abdominal procedures)
• History of ischemic heart disease
• History of congestive heart failure
• History of cerebrovascular disease
• Insulin-dependent diabetes mellitus
• Preoperative serum creatinine >2 mg/dL
• Age >75 years

Combine RCRI with surgical risk estimation using the American College of Surgeons NSQIP risk calculator (http://www.riskcalculator.facs.org) to estimate risk of major adverse cardiac events (MACE) 1

Step 3: Proceed Based on Risk Level

• Low risk (<1% MACE): Proceed to surgery without further cardiac testing, even in patients with multiple risk factors undergoing very low-risk procedures (e.g., cataract, breast surgery) 1, 2
• Elevated risk: Proceed to functional capacity assessment 1

Step 4: Assess Functional Capacity

Determine functional capacity using objective measures such as the Duke Activity Status Index (DASI) or assess ability to perform ≥4 metabolic equivalents (METs) of activity 1

• Moderate to excellent capacity (≥4 METs): Proceed to surgery without further testing 1, 2
• Poor (<4 METs) or unknown capacity: Consider pharmacological stress testing only if results will impact decision-making (willingness to undergo revascularization or change surgical plan) 1

Specific Condition Management

Hypertension

• Stage 3 hypertension (SBP ≥180 or DBP ≥110 mmHg) must be controlled before elective surgery 1
• Establish effective regimen over days to weeks for elective cases; use rapid-acting agents for urgent cases 1
• Beta-blockers are particularly attractive agents for blood pressure control perioperatively 1
• Continue all antihypertensive medications through the perioperative period (critical to avoid rebound) 1

Diabetes Mellitus

• Measure HbA1c preoperatively for risk stratification, aiming for <7% to reduce complications 2
• If HbA1c ≥8%, refer to endocrinology and delay elective surgery until improved 4
• Insulin-dependent diabetes is a specific risk factor requiring heightened perioperative monitoring 1
• Monitor closely postoperatively for wound infection and delayed healing 5

Additional Comorbidities Requiring Assessment

Renal dysfunction: 1, 4

• Order BUN/creatinine for patients with hypertension, heart failure, chronic kidney disease, complicated diabetes, or those taking diuretics, ACE inhibitors, ARBs, NSAIDs, or digoxin
• Creatinine >2 mg/dL is an independent predictor of perioperative cardiac morbidity

Obesity: 1

• Screen for obesity hypoventilation syndrome and obstructive sleep apnea with polysomnography if symptoms present
• Obtain chest radiograph to evaluate for heart failure, cardiac enlargement, or pulmonary hypertension
• Use weight-based (not fixed-dose) thromboprophylaxis

Preoperative Testing Recommendations

12-Lead ECG

• Reasonable for patients with known coronary disease, significant arrhythmia, peripheral arterial disease, cerebrovascular disease, or structural heart disease, except for low-risk surgery 1, 2
• May be considered for asymptomatic patients with ≥1 clinical risk factor undergoing vascular procedures 1, 2

Laboratory Testing

• Hemoglobin/hematocrit: Obtain baseline values for all patients to predict transfusion need 4
• Coagulation studies (PT, aPTT, platelets): Only for patients on anticoagulants, with liver disease, hematopoietic disorders, or abnormal bleeding history 4
• Renal function: For patients with conditions or medications affecting kidney function 4
• HbA1c: For diabetic patients if poorly controlled or results would change management 2, 4

Stress Testing

• Not routinely recommended before noncardiac surgery 3
• Consider only in patients with ≥3 risk factors or poor/unknown functional capacity when results will impact management 1, 3
• Delays surgery by up to 3 weeks in patients with 0-2 risk factors without improving outcomes 3

Preoperative Optimization (Ideally 30 Days Before Surgery)

Medications

• Statins: Start in all vascular surgery patients and those with cardiac risk factors using long-acting formulations (e.g., fluvastatin 80 mg daily) 2, 3
• Beta-blockers: Consider for patients with ≥1 risk factor, starting low-dose (bisoprolol 2.5-5 mg daily) 1 month before surgery, titrated to heart rate 60-70 bpm with systolic BP >100 mmHg 2, 3
• ACE inhibitors/ARBs: Consider for patients with heart failure and LVEF <40% 2

Lifestyle Modifications

• Smoking cessation: Implement at least 4 weeks before surgery to reduce respiratory and wound-healing complications 2
• Alcohol abstinence: Strongly recommended for 4 weeks in patients consuming >2 units daily 2

Critical Pitfalls to Avoid

• Never view preoperative evaluation as simply "giving clearance"—it is comprehensive risk assessment and optimization 2
• Do not perform tests that will not influence perioperative management (e.g., routine stress testing in low-risk patients) 1, 2, 3
• Avoid inadequate communication with the surgical and anesthesia teams about findings and recommendations 2
• Do not restart ACE inhibitors postoperatively until patient is euvolemic to prevent renal dysfunction 2
• Never use fixed-dose thromboprophylaxis in obese patients—use weight-based dosing 5
• Avoid delaying emergency surgery beyond 12-24 hours for extensive cardiac workup when acute surgical indication exists 5

Multidisciplinary Communication

Effective teamwork requires clear communication among patient, primary care physician, anesthesiologist, consultant, and surgeon regarding: 1, 2

• Identified risk factors and their severity
• Optimization strategies implemented
• Perioperative monitoring recommendations
• Postoperative management plans