Preoperative Cardiac Assessment

  1. Basic algorithm:
    Is this an emergency surgery? If yes, proceed with surgery and evaluate cardiac risk postoperatively. Is the patient young, without systemic disease, and going for a minor surgery or procedure? If yes, proceed with surgery.
  2. Revised Cardiac Risk Index:
    Assign 1 point to each of the following risk factors if present:
    • High risk surgery? (intraperitoneal, intrathoracic, suprainguinal vascular).
    • Ischemic heart disease? (history of MI or current angina, use of SL NTG, positive stress test, Q waves on ECG, or history of PTCA/CABG with ongoing chest pain).
    • History of CHF?
    • History of cerebrovascular disease (CVA/TIA)?
    • Diabetic requiring insulin?
    • Pre-op creatinine > 2.0 mg/dl?

    Assign a risk class to determine cardiac complication rate (listed below):
    • Class I: zero risk factors: 0.4%
    • Class II: 1 risk factor: 0.9 %
    • Class III: 2 risk factors: 6.6%
    • Class IV: 3 or more risk factors: 11.0%

    Exceptions: works well for all patients except those undergoing major vascular surgery.

    If patients are Class III or Class IV, strongly consider preoperative noninvasive testing and risk reduction to limit cardiac complications.
  3. What if I have a patient undergoing major vascular surgery?
    Use the AHA/ACC guidelines, which feature a complex algorithm that is based on functional capacity, clinical predictors, and procedure-specific risks (see reference below).

    Delay surgery and proceed to direct treatment/risk reduction if patient has a major clinical predictor of postoperative cardiac complication. Noninvasive testing may not be helpful here because of the high rate of false negatives. Major clinical predictors are defined as:
    • Unstable coronary syndromes (recent MI, unstable or severe angina)
    • Decompensated CHF
    • Symptomatic or uncontrolled arrhythmias (such as symptomatic ventricular arrhythmias, SVT with uncontrolled rate, high grade AV block)
    • Severe valvular disease

    Simplified version of the AHA/ACC algorithm: Use noninvasive testing if the patient has at least 2 of the following risk factors:
    • intermediate clinical predictors: mild angina, prior MI, compensated or prior CHF, diabetes mellitus, renal insufficiency
    • poor functional capacity, defined as < 4 METs: cannot do more than walk 1-2 blocks on level ground or light housework, such as washing the dishes or dusting. Cannot climb a flight of stairs or walk up a hill.
    • high risk surgery: emergency procedure, vascular surgery, prolonged procedure, or anticipated large fluid shifts or blood loss.
  4. What are defined as cardiac complications?
    Hard end-points: MI, cardiovascular death (by MI, arrhythmia, heart failure).
    Soft end-points: non-fatal arrhythmia, CHF/pulmonary edema, ischemia.
  5. How can you reduce cardiac risk?
    • Consider a lower risk alternative to the planned type of operation.
    • Consider using epidural or spinal anesthesia.
    • Correct, modify, and optimize the management of co-morbid medical conditions.
    • Recent MI: delay surgery for 6 months; if the surgery is semi-elective, fully evaluate/optimize from cardiac standpoint and wait at least 6-12 weeks.
    • CHF: optimize and avoid over-diuresis (patient should not be orthostatic)
    • Aortic stenosis: in general, go with symptoms (syncope, CHF, angina). If the patient has symptoms, evaluate fully (obtain echocardiogram, rule out other causes of symptoms). However, if the patient has no symptoms (make sure they are active enough to produce symptoms), then proceed with surgery. This even applies to patients who have severe AS. Patient with critical AS and without symptoms should only undergo procedures that are truly necessary.
    • Use perioperative beta-blockers (See Medicine Consultation: Perioperative Beta-Blockers).
  6. Take home points:
    • Since perioperative cardiac morbidity and mortality is very common and obviously important, cardiac risk assessment should take place in all pre-op medicine consults, even if you are not explicitly asked this question.
    • Most cases of cardiac risk assessment are determined simply by a good history and physical exam.
    • It is often helpful to give an estimate of the percentage risk of cardiac complications (see above, by risk class) so that the surgeons can make the most educated decision regarding whether or not to proceed with surgery.
    • Remember that guidelines are only one facet in the medical decision-making processÂūthey should not replace sound clinical judgment. Evaluate each patient on an individual basis and avoid an algorithmic approach.