How should Diltiazem (calcium channel blocker) be managed perioperatively (peroperative period) in patients undergoing surgery?

Perioperative Management of Diltiazem

Continue diltiazem in patients already taking it chronically for dysrhythmia control or angina, as abrupt discontinuation risks rebound complications, but do not initiate diltiazem perioperatively for cardiovascular risk reduction as it provides no mortality benefit and increases risks of hypotension and bradycardia. 1

For Patients Already on Chronic Diltiazem Therapy

Continue Through the Perioperative Period

• Patients on chronic diltiazem (for atrial fibrillation, rate control, or angina) should continue their medication perioperatively to prevent rebound tachyarrhythmias and maintain therapeutic benefits 1

• Diltiazem can be taken on the morning of surgery with a small sip of water, similar to other chronic cardiac medications 2

• Monitor closely for intraoperative hypotension and bradycardia, as nondihydropyridine calcium channel blockers like diltiazem carry increased risk of these complications 1

• If oral administration is not feasible perioperatively, transition to intravenous diltiazem to maintain therapeutic effect 3, 4

Specific Surgical Context: Thoracic Surgery

• In patients undergoing pulmonary lobectomy or thoracic surgery, continuation of diltiazem is specifically recommended to reduce postoperative atrial fibrillation, which occurs in 12-18% of thoracic surgery patients 1

• This recommendation applies to patients already on calcium channel blockers with antiarrhythmic properties 1

Do NOT Initiate Diltiazem Perioperatively

Evidence Against New Initiation

• Perioperative initiation of diltiazem does not reduce mortality or myocardial infarction in patients undergoing noncardiac surgery 1

• Meta-analysis of 11 randomized trials (1,007 patients) showed no benefit for perioperative mortality or MI with calcium channel blocker initiation 1

• Moderate-to-high quality evidence demonstrates significant increased risk of hypotension and bradycardia with perioperative calcium channel blocker initiation 1

Limited Exception: Thoracic Surgery in Drug-Naïve Patients

• In patients undergoing thoracic surgery who are NOT already on antiarrhythmic therapy, introduction of diltiazem intraoperatively or immediately postoperatively may be considered to reduce postoperative atrial fibrillation, but only after careful assessment of benefit-risk balance 1

• This is a weaker recommendation (probably recommended) and should account for individual bleeding risk, hemodynamic stability, and baseline heart rate 1

Intraoperative Management Considerations

Hemodynamic Monitoring

• Expect and prepare for potential intraoperative hypotension in patients continuing diltiazem, particularly during induction and maintenance of anesthesia 1

• Have vasopressor support readily available (phenylephrine, norepinephrine) to manage hypotension without discontinuing the medication 2

• Monitor heart rate closely as diltiazem's negative chronotropic effects may be exaggerated under anesthesia 1

Special Surgical Populations

• In abdominal surgery patients receiving diltiazem, monitor oxygenation carefully as one study showed decreased arterial oxygen tension (PaO2 from 210.8 to 193.2 mmHg) 15 minutes after diltiazem infusion 5

• For cardiac surgery patients, diltiazem infusion has demonstrated cardioprotective effects and reduced supraventricular arrhythmias, but this is a distinct population from noncardiac surgery 6, 4

Common Pitfalls and Caveats

• Do not confuse diltiazem (nondihydropyridine) with dihydropyridine calcium channel blockers (amlodipine, nifedipine) - they have different perioperative considerations and primary indications 1

• Avoid starting diltiazem on the day of surgery in drug-naïve patients outside of specific thoracic surgery protocols, as evidence does not support benefit and risks are significant 1

• Do not discontinue chronic diltiazem abruptly due to risk of rebound tachyarrhythmias, particularly in patients with atrial fibrillation or flutter 1

• If hypotension occurs with continued diltiazem, treat with vasopressors rather than discontinuing the medication acutely, unless hemodynamic instability is severe 2

• Diltiazem's effects on heart rate may mask compensatory tachycardia in response to hypovolemia or bleeding - maintain high index of suspicion for occult blood loss 1