What is the recommended preoperative evaluation for a patient with a history of diabetes, hypertension, or heart disease undergoing surgery?

Preoperative Evaluation for Patients with Diabetes, Hypertension, or Heart Disease

For patients with diabetes, hypertension, or heart disease undergoing noncardiac surgery, preoperative testing should be driven by specific clinical findings and medications rather than performed routinely—obtain ECG for those undergoing intermediate- or high-risk surgery, electrolytes and creatinine for those on diuretics/ACE inhibitors/ARBs, and A1C only if results would change perioperative glucose management. 1

Risk Stratification Framework

The first step is determining surgical risk category and identifying active cardiac conditions that mandate preoperative optimization: 1

• Active cardiac conditions requiring evaluation before surgery: unstable angina, recent myocardial infarction, decompensated heart failure, significant arrhythmias, or severe valvular disease 1
• Surgical risk categories: Low-risk procedures (cataract, endoscopy) vs. intermediate-risk (intra-abdominal, orthopedic) vs. high-risk (vascular, prolonged procedures with large fluid shifts) 1
• Functional capacity assessment: Patients who can climb ≥2 flights of stairs or achieve ≥4 METs can generally proceed without further cardiac testing 1, 2

Electrocardiography (ECG)

ECG is indicated for patients with diabetes, hypertension, or known cardiovascular disease undergoing intermediate- or high-risk surgery. 1, 2

• Patients with coronary artery disease, heart failure, cerebrovascular disease, diabetes mellitus, or renal insufficiency undergoing vascular surgery require preoperative ECG 1
• For intermediate-risk surgery, ECG is reasonable when one or more clinical risk factors are present 1
• Asymptomatic patients undergoing low-risk surgery do not require ECG regardless of comorbidities 1

Common pitfall: Do not order ECG based on age cutoffs alone—the decision should be driven by comorbidities and surgical risk, not arbitrary age thresholds. 2

Electrolytes and Renal Function Testing

Obtain electrolytes and creatinine for patients with hypertension, heart failure, diabetes, or chronic kidney disease, and for all patients taking diuretics, ACE inhibitors, ARBs, NSAIDs, or digoxin. 1

• The consensus across guidelines is that history and physical examination findings—specifically the presence of hypertension, heart failure, chronic kidney disease, complicated diabetes, or liver disease—should drive testing decisions rather than age alone 1
• Medications that predispose to electrolyte abnormalities (diuretics, ACE inhibitors, ARBs, NSAIDs, digoxin) are compelling indications for preoperative electrolyte and creatinine measurement 1

Glucose and Hemoglobin A1C Testing

For patients with known diabetes, obtain preoperative A1C only if results would change perioperative glucose management; random glucose testing in well-controlled diabetics rarely alters management. 1

• Random glucose reflects control over only the past few hours and does not provide actionable information for perioperative planning in patients with known diabetes 1
• A1C provides a more useful assessment of glycemic control over the preceding 2-3 months and should be obtained if results would influence perioperative insulin or glucose management protocols 1
• Random glucose measurement can be considered for patients at very high risk of undiagnosed diabetes based on clinical presentation 1

Key nuance: The incidence of occult diabetes in presurgical populations is only 0.5%, so universal screening is not justified—testing should be reserved for situations where results would alter perioperative care. 1

Complete Blood Count (CBC)

CBC is not routinely indicated for patients with diabetes, hypertension, or stable heart disease unless there is history of anemia, recent blood loss, or diseases increasing anemia risk (liver disease, hematologic disorders, chronic kidney disease). 2

• CBC should be performed when significant perioperative blood loss is anticipated or for patients undergoing cardiovascular surgery 2
• The presence of diabetes, hypertension, or stable heart disease alone does not mandate CBC testing 2

Coagulation Studies

Coagulation testing is not indicated for patients with diabetes, hypertension, or heart disease unless they have a personal or family history of bleeding disorders, liver disease, or are taking anticoagulants. 1

• The prevalence of inherited coagulopathies is low, and routine screening in asymptomatic patients is not warranted 1
• Obtain bleeding history from all surgical patients—spontaneous bruising, excessive surgical bleeding, or family history of heritable coagulopathy warrant coagulation testing 1

Chest Radiography

Chest radiography is not indicated for asymptomatic patients with stable diabetes, hypertension, or heart disease—obtain only if there are new or unstable cardiopulmonary signs or symptoms on examination. 1, 2

• Abnormal findings on screening chest radiography are usually chronic and predictable from history or physical examination, and rarely alter perioperative management 1
• Consider chest radiography for patients at risk of postoperative pulmonary complications only if results would change perioperative management 2

Left Ventricular Function Assessment

Assess left ventricular function for patients with current or poorly controlled heart failure, or for those with prior heart failure and dyspnea of unknown origin. 1

• Routine assessment of left ventricular function is not indicated in patients without prior heart failure 1
• If previous evaluation has documented severe left ventricular dysfunction, repeat preoperative testing may not be necessary 1

Algorithm for Clinical Decision-Making

1. Identify active cardiac conditions (unstable angina, decompensated heart failure, significant arrhythmias, severe valvular disease)—these require evaluation and optimization before proceeding 1

2. Assess functional capacity—if patient can climb ≥2 flights of stairs, proceed without further cardiac testing 1, 2

3. Determine surgical risk category (low, intermediate, or high-risk) 1

4. Order ECG if undergoing intermediate- or high-risk surgery with diabetes, hypertension, or known cardiovascular disease 1, 2

5. Order electrolytes and creatinine if patient has hypertension, heart failure, diabetes, chronic kidney disease, or takes diuretics/ACE inhibitors/ARBs/NSAIDs/digoxin 1

6. Order A1C in diabetic patients only if results would change perioperative glucose management protocols 1

7. Avoid routine CBC, coagulation studies, chest radiography, and urinalysis unless specific clinical indications are present 1, 2

Critical pitfall to avoid: Do not order tests "just to be safe" or based on institutional protocols—only order tests that would alter perioperative care based on the patient's specific clinical characteristics and the planned surgical procedure. 2