Epidemiology of Noncardiac Surgery

Dr. Mohammed Naser

Overview

• Important Decision points:– Urgent vs Elective Surgery– High risk surgery vs intermediate vs low

-Active Cardiac Condition vs non-active

Functional capacity on basis of pt ablility

To perform certain activities

The Search For High Risk

Methods for Assessing Risk Pre-Operatively

Is the surgery emergency

PROCEED and manage post operatively

according to AHA& ACC guidelines

If the surgery emergency..??

Active/Major Cardiac Conditions

• Unstable Coronary Conditions

• Decompensated CHF

• Significant arrhythmias (i.e. 3 HB, new ⁰Vtach)

• Severe Valvular Disease (aortic stenosis >40 mm hg gradient or valve area <1.0cm₂)???????

Non-Active Cardiac Factors

• Intermediate Risk • Hx of CHD• History of prior

CHF• Hx of stroke• Diabetes • Renal insufficiency

• Minor Risk*• Age > 70• Abnormal ECG• Nonsinus rhythm• Uncontrolled

systolic BP

* Not associated with cardiac risk

Six Independent predictors of cardiac risk

1) ischemic heart disease

2) congestive heart failure

3) cerebrovascular disease

4) high risk surgery (AAA, orthopedic sx)

5) pre-operative insulin tx for diabetes

6) preoperative creatinine for creat > 2 mg/dL

Lee et al

Functional capacity

Functional Capacity

• Functional status has shown to be a reliable periop and long-term predictor of cardiac events

• MET: metabolic equivalent resting oxygen consumption of 70 kg, 40 yr old man at rest

• Periop risk is increased if person cannot > 4 METS

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The Trump Card: Functional Capacity

• Perioperative cardiac risk is increased in patients unable to exercise 4 METs

• Functional capacity can be estimated in the office

– Energy expenditure for eating, dressing, walking around house, dishwashing ranges from 1-4 METs

– Climbing a flight of stairs, running a short distance, scrubbing floors, and golf ranges from 4-10 METs

– Swimming and singles tennis exceeds 10 METs

Surgery Risk Type

Type Cardiac risk examples

High > 5% Aortic, peripheral vasc sx

Intermediate risk 1-5% IntraperitonealIntrathoracicCarotid EndHead and neckOrthopedic SxProstate Sx

Low <1% Endoscopic proceduresSuperficialCataract SxBreast SxAmbulatory Sx

Surgery-Specific Risk: High Risk*

• Major emergency surgery

• Vascular surgery including: aortic surgery, infra-inguinal bypass

• Prolonged surgery with large fluid shifts or blood loss

* Reported risk of cardiac death or nonfatal MI >5%

Stepwise Approach

• Step 1: Determine urgency of surgery

• Step 2: Active cardiac condition?-→test

• Step 3: Undergoing low-risk surgery? < 1%*

• Step 4: Good functional capacity?

* Combined morbidity and mortality < 1% even in high risk

patients

The Catheterization Questions to Ask Yourself

• Does this patient have symptomatic coronary disease that will have a mortality benefit from revascularization now?

• Am I willing to send the patient to CABG?

• Am I doing this just to know the anatomy?

Is pre-op coronary revasc advantageous?

• If high risk surgery and patient has active cardiac issue

• Functional test and perfusion Imaging and if

• L main 50% or 3 VD, 2VD + LAD Prox, LVEF < 20%, aortic stenosis – consider revasc pre-op

STENTS

If upcoming Sx is known then PTCA alone or BMS with 4-6 wks dual antiplatelet tx after

If received DES....– 1) postpone sx until > 12 months,– 2) do sx on both asa+clop – 3) do sx on single ap tx

Use of a DES for coronary revascularization before imminent or planned non cardiac sx that will necessitate d/c of antiplatelet agents is not recommended

Medical tx

1) beta blockers-if on keep them if not....

2) Statins continue, ? Start -need randomized trials

Other Issues

• DVT/PE prophylaxis

• Anesthetic technique-volatile agent with general anesthetic - ↓ troponin ↑ LV function >> propofol, midazolam, balanced anesthesia (Grade B)

• No evidence that epidural anesthesia >>general anesthesia for cardiac outcomes

• Routine troponin monitoring not recommended

Surveillance for Perioperative Myocardial Infarction

• ECGs–All intermediate and high-risk patients

should get a post-op ECG.–As need for signs or symptoms of

ischemia

• Troponin / CK – In patients with signs or symptoms of

ischemia–Do not do screening biomarkers

High Risk Features

• Severe obstructive or restrictive pulmonary disease

• Diabetes

• Renal impairment

• Anemia, polycythemia, thrombocytosis

PCI pre-op

• ST-elevation MI

• Unstable angina

• Non ST elevation MI

2007 ACC/AHA Perioperative Guidelines

Take Home Messages

Take Home Messages• Unstable syndromes require management prior to surgery. Look

for

– Unstable angina

– Signs of heart failure

– Stenotic valve lesions

– Ventricular arrhythmias

• Functional tolerance is the best single predictor of outcome

• Be very specific in your history (one step at at time, regular or slow pace, etc)

• If patient on beta blockers & statins continue them, more trials to mandate them

• PCI/CABG only if patient needs it independent of surgery. Think twice because of stent data and delays.