Table of contents
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Introduction
- Rather than providing "clearance" for surgery, perioperative medicine should focus on three objectives:
- Optimize baseline health and chronic disease mgmt
- Assess risk + discussion to ensure informed choice is made
- Identify post-op risks
Preoperative Evaluation
- Routine diagnostic tests are NOT indicated preoperatively.
- Multiple studies: poor yield + poor risk correlation
- Choosing wisely: Recommends against routine labs & imaging for healthy patients undergoing low-risk surgery (i.e. eye).
- Let patient-specific factors guide, examples:
- Serum electrolytes in patients on diuretics
- Creatinine in CKD
Medication reconciliation
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- Review all medications and optimize medical therapy
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Medication Recommendation Anticoagulants Continue for minor surgery, d/c for major.
IV heparin 4-6h pre-op
LMWH: 24h pre-op (12h if prophylactic dose)
Warfarin: 5 days
TSOAC: 1-2d (normal GFR), 3-6d (eGFR < 50)
Antiplatelet Clopidogrel: d/c 5-7d pre-op, continue if cardiac stent
ASA: Continue if minor OR. Continue if recent MI (6mo), stent, high risk CAD. Or discontinue 7-10d pre-op (other than CABG)
Cardiovascular Continue BB, CCB, nitrates, antiarrhythmics.
ARB/ACEi controversial (intra-op hypotension), usually continue, diuretics often held on day of OR
Lipid Lowering Coninue statins (hold other lipid lowering drugs) Hypoglycemic Oral hypoglycemic agents: d/c 12-72hrs pre-OP (depends on half-life and hypoglycemia risk)
Short-Acting Insulin: Hold AM of OR
Intermediate-acting: Reduce to 1/2 (usually)
Long-acting: coninue, or reduce to 2/3
Steroids Coninue; Give stress dose if indicated Estrogen D/c few weeks pre-op (if continue, increase DVT proph) Psych Small risk of serotonin syndrome w/ anesthetics (weigh risks/benefits)
MAOIs d/c 10-14 pre-op, SSRI/TCA decide or taper
Analgesic NSAIDs and COX-2 inh are d/c 7d preop. Immunomodulating Transplant recipients:
- Keep all meds (Except sirolimus: hold due to wound dehiscence)
Non-Transplant patients:
- DMARDS + biologics: stop > 4 half-lives prior to surgery. Restart when wounds heal. (2-4w after surgery).
- Continue methotrexate and hydroxychloroquine (do not impact wound healing)
Pulmonary
GI (PPI, H2B)
Thyroid
Psych
Generally continue
Cardiovascular Management
- See 2014 AHA / ACC perioperative cardiovascular guideline
- Key Principles:
- Emergency Surgery: Do not delay for cardiac testing
- Patients during ACS: Should delay surgery until ACS is assessed and treated
- IF do not fall in above groups... do they have risk factors?
- If patient has no risk factors, history, or symptoms --> NO perioperative evaluation required
- If patient has risk factors:
- Determine risk for major adverse cardiac event (MACE).
- RCRI --> most common, easiest to use.
- Overestimates risk in low-risk or ambulatory surgery
- Underestimates risk in vascular surgery
- RCRI --> most common, easiest to use.
- Determine risk for major adverse cardiac event (MACE).
- Calculate MINS
- Low < 1% risk of MACE
- High ≥ 1% risk of MACE
- Low Risk Surgery: Endoscopic etc..
- High Risk Surgery: Vascular Etc
- "Intermediate was removed"
- Risk:
- RCRI (underestimates vascular surgery risk)
- VSG-CRI - For Vascular Surgery group - Cardiac Risk Index
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Canadian guidelines include:
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BNP screening in high risk patients
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Removed functional status
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Post-MI / Stents
- Note: premature discontinuation of ASA or second antiplatelet agent post-MI or post-Stent is a strong predictor of peri-op MI and mortality.
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2016 AHA Guidelines for Post-MI and Post-Stent antithrombotic management:
- Do not interrupt dual antiplatelet therapy unless:
- 30 Days Post Bare Metal Stent
- 6 Months Post Drug Eluting Stent
- Unless uncontrolled bleeding or urgent life-saving surgery
- (This is a change from 2014 Guidelines)
- Do not interrupt dual antiplatelet therapy unless:
Landmark Trials
- POISE Trial: Post-OP MI is 5% at 30 days.
- Defined as: troponin elevation. (problem)
- MINS Trial:
- Peri-OP MI: supply/demand mismatch (catecholamines, stress, reduced fibrinolytic activity, hypercoagulability, BP shifts, induction agents and labile BP, tahycardia).
- Study: plaque rupture 50% of cases.
- Landmark trials:
- CARP (Like COURAGE TRIAL for stable coronary disease, but same for peri-operative).
- Elective major vascular surgery (highest risk surgery) randomized to revascularization with cath or CABG. (50% prevalence of CAD)
- If >70% stenosis --> randomized to revasc vs. not. (excluded prev revasc, if L-main disease, or LAD w/ LV dysfxn).
- No difference, so if stable coronary disease, no need to revasc (just delays surgery due to antiplts).
- POISE I (2008 - McMaster)
- 8000pts, multicenter RCT, RCRI (intermediate/high risk pts).
- metoprolol 100mg 2-4hrs pre-op then 200mg po x30d. (criticism: high doses!)
- CV death, nonfatal MI, fatal MI --> LESS EVENTS IN CV GROUP.
- Stroke risk was higher likely due to hypotension (significantly). So Risk vs. Benefit
- CONCLUSION: Continue BB if on them chronically. In patients with intermediate/high risk of ischemia may be reasonable to begin BB, but start few weeks before (>1w). Do not give BB on day of surgery.
- POISE II
- ASA on day of CV surgery.
- 200mg of ASA on day of surgery, followed by 100mg daily for 30d. (if on asa previously, stop for 72hrs, then do this).
- Excluded recent stents, excluded endarterectomy (on ASA already)
- Post-op trop 6-12hrs, day 1 and day 3.
- NO DIFFERENCE in MI, death, non-fatal MI. INCREASED bleeding risk.
- Increased bleeding risk can drive MI risk.
- Restart 8-10 days post-op when bleeding risk is lower.
- 200mg of ASA on day of surgery, followed by 100mg daily for 30d. (if on asa previously, stop for 72hrs, then do this).
- ASA on day of CV surgery.
- POISEII - SECOND 2X2 ARM
- Perioperative low-dose clonidine (discontinue usual anti-hypertensives the morning of surgery, given clonidine).
- Did not reduce MI, but more non-fatal cardiac arrests in clonidine group.
- More hypotension and bradycardia in clonidine group.
- Perioperative low-dose clonidine (discontinue usual anti-hypertensives the morning of surgery, given clonidine).
- VISION trial
- Background; Troponin elevation worsens outcomes. Most pts on analgesics, and don't feel MI.
- 15,000pts undergoing non-cardiac surgery >45yo WITH OVERNIGHT STAY!
- Measured Troponin on days 1 & 3 and evaluated 30d mortality (most didn't meet MI standards)
- Results: Troponin predicts mortality and morbidity post-surgery.
- Supports post-op surveillance
- Data:
- MINS (criteria TnT ≥ 0.03 ng/mL or Tn > 30)
- No MINS: 1.1% death at 30 days
- MINS 9.8% death at 30 days (>3 times increase mortality)
- 84% asymptomatic
- MINS (criteria TnT ≥ 0.03 ng/mL or Tn > 30)
- Rodseth 2014
- 2179pts - 18 studies
- Pre-op BNP independentlyl associated with death or nonfatal MI at 30 days after NCS
- NT-proBNP < 300 ng/L (or BNP < 92 ng/L) - 4.5% risk
- NT-proBNP ≥ 300 ng/L or BNP ≥ 92 ng/L - 21% risk
- recommend daily troponin for 48-72hrs.
- CARP (Like COURAGE TRIAL for stable coronary disease, but same for peri-operative).
- Statins:
- DECREASE III trial
- Excluded if on statin already.
- Used fluvastatin 37d prior to surgery. (fluvastatin = long half-life).
- Outcome: MI, ischemia on ECG, trop elevation etc,,
- Fewer MIs in fluvastatin group.
- Conclusion: DO NOT stop statins, continue.
- Conclusion: if vascular patient not on statins, can start one.
- DECREASE III trial
- DO NOT workup/treat conditions that would not be worked up or treated if they were not going for surgery.
Hypertension
- Pre-Op delay surgery if BP > 180-200/110 -- until better BP control
- During induction of anesthesia about 90mmHg BP variations (up or down), and can be dangerous.
- Post-Op:
- Generally control BP if > 180/110
- Causes: MANY! (Pain, Alcohol Withdrawal!!!!)
- Generally control BP if > 180/110
Anticoagulation Management
Patient thrombosis risk should be weighed with bleeding risk - based on both patient and surgery/procedure factors
2012 Periprocedural Management of Oral Anticoagulants
VKAs
- Low risk of TE- no bridging
- Intermediate risk of TE
- Low risk of bleed - consider bridging
- High risk of bleed - no bridging
- High risk of TE - bridging
*** BRIDGE trial (2015) suggests that both low and all intermediate risk groups for TE should not be bridged, but guidelines do not reflect this yet ***
DOACs
- Recommended to hold 4 half lives prior to high-risk of bleed procedure (~3 days prior)
- May be able to hold only 2 days prior for low-risk of bleed procedures
UNDER CONSTRUCTION
- No need to stop anticoagulant therapy for minor dental procedures (includes extractions) [Source: NEJM K+]
Components of Peri-Op Assessment
Cardiac Risk
- Identify RF's of complications.
- Establish risk profile, help make informed decision about surgery.
- MACE = Major Adverse Coronary Event
- Surgery Risk Factors
- Low < 1% risk of MACE
- Endoscopic, superficial, cataract, breast, ambulatory
- High ≥ 1% MACE
- Vascular, intraperitoneal, intrathoracic, head&neck, suprainguinal.
- Low < 1% risk of MACE
- Patient Risk Factors:
- Functional Capacity: METs
- LEE Index/RCRI
- Most common
- Underestimates risk of vasc surgery (use VSG-CRI)
- Not Surgery sapecific.
- Score 0-3: risk 0.4% - 11%)
- Score ≥ 2 = >1% risk of MACE = high risk.
- VSG-CRI: If Vascular surgery (Vascular Surgery Group)
- Carotid en
- Gupta
- ASA class, procedure type, etc..
- Easy to use.
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