OakLeaf Medical Network Healthy Viewpoints, Winter 2003
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Abd Khatib, MD, FACC

Preoperative Risk Assessment and Risk Reduction Before Surgery

Abd Khatib, MD, FACC
Cardiology
Eau Claire Heart Institute
Eau Claire


Every time we do surgery or an intervention there is risk involved.  It is important to measure each individual patient’s risk before any surgery and to reduce risk to a minimum, because the operating room is not a place for surprises.  Perioperative myocardial infarction, which is a heart attack around the time of the surgery, is the main cause of morbidity and mortality (complications and death) in patients undergoing non-cardiac surgery. 

 


Preoperative management aims at optimizing the patient’s condition by identifying underlying cardiac risk factors and diseases.  

During surgery the patient might be susceptible to prolonged myocardial ischemia, which is decreased oxygen supply to the heart due to the stress of the surgery in the presence of significant narrowing of the coronary arteries.  This will lead to subendocardial ischemia (decreased blood flow to the inner area of the heart muscle) or may lead to coronary occlusion after a plaque rupture with subsequent blood clot formation.

Systemic medical therapy prior to surgery aims to prevent mismatch of myocardial oxygen supply and demand, and to stabilize coronary plaques to reduce the risk of perioperative myocardial infarction.  Medications called beta-blockers, statins and aspirin are widely used for this purpose in this setting.

Around the time of surgery, patients should change their life-style and medical therapy to lessen the impact of cardiovascular risk factors, as the patient should live long enough after the operation to enjoy the benefit of the surgery.  

Predictors of major cardiovascular complications include:

  • Surgery lasting more than one hour in duration.
  • Ischemic heart disease, such as coronary arteriosclerosis, myocardial infarction, or poor circulation to the lower extremities.
  • Congestive heart failure where the body starts to fill up with an
    extra amount of fluid.
  • Previous stroke or CVA (cerebro-vascular accident).
  • Insulin-dependent diabetes mellitus.
  • Renal (kidney) failure.

 


Depending on the presence of one or more of these factors, we can predict the rate of major cardiac complication after surgery.  Complication risk is less than 0.4% if none of these factors are present and 0.9% , 7%, and 11%, if one, two or three factors are present.  The use of beta-blockers was associated with a significant decrease in the size of the atheroma (cholesterol build-up) in the artery.  Highly selective beta 1-blockers are most recommended and long acting beta-blockers are better than short-acting ones.

Cholesterol lowering agents called statins have demonstrated to decrease lipid, lipid oxidation, inflammation and cell death. These properties of statins may stabilize coronary plaques thereby preventing their rupture and subsequent myocardial infarction in the perioperative period.  Side effects such as statin-induced myopathy (muscle damage) and rhabdomyolysis (muscle destruction) are a major concern, but the potential benefit of perioperative statin therapy appeared to outweigh the risk of potential hazard. Therapy should be initiated a few days before surgery in combination with dose adjustment for tight heart rate control.  It is strongly advised to continue the beta-blocker therapy throughout the perioperative period. Additionally, there is benefit in continuation of beta-blocker use, even up to 30 months after surgery.


 ~ For more information or to schedule an appointment
with Dr. Abd Khatib, Eau Claire Heart Institute,
call  715.831.4444 or visit www.echeart.com.

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