What is the management of SGLT2 (Sodium-Glucose Linked Transporter 2) inhibitors and other medications, such as beta-blockers, statins, and antiplatelet agents, before elective Coronary Artery Bypass Grafting (CABG), and what preoperative workup is recommended?

Perioperative Medication Management for Elective CABG

SGLT2 Inhibitors: Critical Preoperative Discontinuation Required

SGLT2 inhibitors must be discontinued at least 3-4 days before elective CABG to prevent life-threatening euglycemic diabetic ketoacidosis (euDKA), which can precipitate acute coronary syndrome and cardiac arrest in the postoperative period. 1, 2, 3

Why This Matters:

• Euglycemic DKA is a potentially fatal complication that presents with severe metabolic acidosis (pH <7.3, anion gap >12 mmol/L) but near-normal glucose levels (<14 mmol/L), making it difficult to detect 1, 4
• Cases have occurred even when SGLT2i were stopped 48 hours preoperatively, suggesting the 24-hour discontinuation previously recommended is insufficient 5
• The metabolic stress from euDKA can trigger myocardial ischemia, effectively acting as a cardiac stress test that precipitates ACS and graft thrombosis 1
• Multiple case reports document euDKA occurring on postoperative days 1-5 after CABG, with symptoms including nausea, vomiting, tachypnea, and hemodynamic collapse 1, 4

Preoperative Management Algorithm:

• Discontinue SGLT2i 3-4 days before elective CABG 2, 3
• If patient presents for urgent/emergent CABG while on SGLT2i: Proceed with surgery but implement intensive ketone monitoring postoperatively 2, 3
• Document SGLT2i use prominently in the medical record to alert postoperative teams 2

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Antiplatelet Agents: Differential Management Strategy

Aspirin (ASA):

Continue aspirin 100-325 mg daily through surgery without interruption 6, 7

• Aspirin reduces operative morbidity and mortality with only modest bleeding risk 7
• If not given preoperatively, initiate within 6 hours postoperatively 6

P2Y12 Inhibitors (Clopidogrel, Ticagrelor, Prasugrel):

For elective CABG:

• Clopidogrel: Stop 5 days before surgery 6, 7
• Ticagrelor: Stop 5 days before surgery 6, 7
• Prasugrel: Stop 7 days before surgery 6, 7, 8

For urgent CABG (cannot wait 5-7 days):

• All P2Y12 inhibitors: Stop at least 24 hours before surgery to reduce major bleeding complications 6
• Surgery may be performed <5 days after clopidogrel/ticagrelor or <7 days after prasugrel if clinically necessary 6

Rationale: P2Y12 inhibitors significantly increase post-CABG bleeding and transfusion requirements, but delaying surgery carries thrombotic risk 6

Glycoprotein IIb/IIIa Inhibitors:

• Eptifibatide or tirofiban: Stop 2-4 hours before surgery 6
• Abciximab: Stop at least 12 hours before surgery 6

Postoperative Resumption:

Resume aspirin and P2Y12 inhibitors within 24 hours after surgery unless contraindicated by bleeding or thrombocytopenia (platelet count <50,000/μL) 6

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Statins: Mandatory Continuation

Never discontinue statins before or after CABG - this is a Class III (Harm) recommendation 6

• All patients undergoing CABG must receive statin therapy unless contraindicated 6, 7
• Target LDL cholesterol <100 mg/dL with at least 30% reduction from baseline 6, 7
• Statin discontinuation increases perioperative risk 7

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Beta-Blockers: Perioperative Continuation Essential

Administer beta-blockers for at least 24 hours before CABG to all patients without contraindications 6, 7

• Reduces postoperative atrial fibrillation and associated complications 6, 7
• Reinstitute as soon as possible after surgery 6, 7
• Prescribe at hospital discharge to all patients without contraindications 6
• Preoperative beta-blockers may reduce in-hospital mortality, particularly in patients with LVEF >30% 6

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ACE Inhibitors/ARBs: Uncertain Safety Profile

The safety of continuing ACE inhibitors or ARBs perioperatively is uncertain 6

• Preoperative administration in patients on chronic therapy has unclear risk-benefit 6
• Initiating before hospital discharge is not well established 6
• Despite uncertainty, ACE inhibitors/ARBs are recommended before CABG 6

Clinical Approach: Continue in stable patients on chronic therapy, but be prepared for intraoperative hypotension requiring vasopressor support

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Glycemic Control: Strict Perioperative Management

Use continuous IV insulin to maintain postoperative glucose ≤180 mg/dL while avoiding hypoglycemia 6, 7

• Reduces deep sternal wound infection and other adverse events 6, 7
• Target intraoperative glucose <140 mg/dL has uncertain effectiveness 6

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Preoperative Workup Essentials

Monitoring Requirements:

• Continuous ECG monitoring for at least 48 hours postoperatively to detect arrhythmias 6, 9
• Hemodynamic monitoring for first 48-72 hours when most complications occur 9

Laboratory Surveillance (if SGLT2i used preoperatively):

• Monitor serum and urine ketones postoperatively to detect euDKA early 2, 4
• Check arterial blood gas if metabolic acidosis suspected (look for pH <7.3, anion gap >12 mmol/L with normal glucose) 1, 4
• Maintain high index of suspicion on postoperative days 1-5 for nausea, vomiting, tachypnea with metabolic acidosis 1, 4

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Critical Pitfalls to Avoid

1. Do not assume normal glucose excludes DKA in patients with recent SGLT2i use - euglycemic DKA is the hallmark complication 1, 5, 4
2. Do not stop statins perioperatively - this increases risk without benefit 6
3. Do not continue P2Y12 inhibitors through elective CABG - bleeding risk outweighs benefit 6
4. Do not delay aspirin resumption >24 hours postoperatively unless active bleeding 6
5. Do not restart SGLT2i in the immediate postoperative period - wait until patient is metabolically stable with normal oral intake 2, 3