Cardiac risk: RCRI, METs, and what to hold day-of

Revised Cardiac Risk Index (Lee 1999) — 6 independent predictors of major adverse cardiac events: (1) high-risk surgery (intraperitoneal, intrathoracic, suprainguinal vascular), (2) ischemic heart disease, (3) CHF, (4) CVA / TIA history, (5) preoperative insulin for diabetes, (6) preoperative creatinine >2.0. Score 0 → 0.4% MACE. Score 1 → 1%. Score 2 → 2.4%. Score ≥3 → ~5.4%. Modern data suggests these underestimate — newer ACS-NSQIP MICA calculator gives higher absolute risks.

1 MET = resting oxygen consumption (~3.5 mL/kg/min). 4 METs = walking up a flight of stairs without stopping, or heavy housework. Old rule: ≥4 METs without symptoms + non-high-risk surgery = no further cardiac workup needed. MET-REPAIR (2021) calls subjective METs unreliable — but absent better data, we still use them. If the patient cannot tell you OR cannot do 4 METs OR has active cardiac symptoms → escalate (functional testing, cardiology consult).

Patients chronically on beta-blockers: KEEP them on. Stopping causes rebound tachycardia + hypertension and increases MACE. STARTING a new beta-blocker right before surgery (old POISE-1 strategy) was harmful — more stroke, more death. So: continue chronic beta-blockers (give the AM dose), but don't initiate perioperatively. If you must initiate (active CAD), start ≥7 days out and titrate.

ACE-Is (lisinopril, enalapril) and ARBs (losartan, valsartan) on morning of surgery → refractory intra-op hypotension resistant to phenylephrine, often requiring vasopressin. Standard: HOLD the AM dose. Resume post-op once volume status stable. Exception: heart-failure indications — discuss with prescriber. POISE-3 (2023) supports the hold for most patients.

Dual antiplatelet therapy (aspirin + P2Y12 like clopidogrel / ticagrelor) after a coronary stent: minimum duration is BMS 1 month, DES 6-12 months (longer with high-risk features). Stopping early → stent thrombosis → STEMI → 30-50% mortality. Elective surgery is DEFERRED until minimum duration completes. If non-deferrable: continue at least aspirin if surgical bleeding risk allows; if P2Y12 held, minimize the gap (5-7 days for clopidogrel, 3-5 days for ticagrelor).

Long-acting insulin (glargine) — give half AM dose. Short-acting insulin — hold AM. Oral hypoglycemics — hold AM (metformin = lactic acidosis risk). SGLT-2 inhibitors (empagliflozin, dapagliflozin) — hold ≥3 days pre-op (euglycemic DKA risk). Warfarin — hold 5 days, INR <1.5 day-of (bridge if mechanical valve or recent VTE). DOACs — hold per CrCl (1-2 days normal, longer if renal impairment). Aspirin — continue for most unless surgical bleeding risk is high (neuro, eye, prostate).