Preoperative Cardiac Assessment with a Phoenix Cardiologist

As many as 27 million people in the U.S. undergo non-cardiac surgery every year. Of those, approximately 50,000 have a preoperative heart attack, one that occurs before surgery. A heart attack is also called a myocardial infarction or MI. Also, over half of preoperative deaths are the result of cardiac events.

People over the age of 65 years are at the greatest risk for cardiovascular disease and cardiac morbidity. Both pre- and postoperative cardiac risks should be assessed for high risk patients.

Reasons for Individual Preoperative Cardiac Assessment

There are many reasons for a preoperative cardiac assessment. The PHoenix cardiologist is consulted to make sure the patient has good enough health to undergo a surgical procedure. The goals of the preoperative cardiac assessment are:

• Identify patients at risk for adverse events before, during, and after surgery
• Evaluate the clinical health status of a patient before they undergo surgery
• Assess the cardiac risks posed by non-cardiac surgery
• Reduce the risk of heart problems before, during, and after surgery
• Improve the long term cardiac outcome for patients
• Identify patients with a poor long term prognosis due to cardiovascular disease

Preoperative Cardiac Risk Factors

• History of ischemic heart disease
• Prior diagnosis of heart failure
• Diabetes mellitus
• Renal insufficiency
• Cerebrovascular disease

History and Physical Examination

The cardiologist takes a detailed history and conducts a comprehensive physical examination to identify cardiac conditions. These include a recent or past heart attack, prior unstable angina, valvular disease, decompensated heart failure, and arrhythmias. Also, the doctor assesses functional capacity and identifies comorbid conditions, such as stroke, peripheral vascular disease, renal insufficiency, lung disease, and diabetes.

Functional Capacity Assessment

A functional capacity exam checks maximum oxygen uptake by treadmill testing. Patients with a functional capacity of 4 to 10 are considered at low risk of perioperative cardiac events. The standard evaluation is as follows:

• 1:  Perform activities of daily living, walk around the house, walk on level ground at 2 mph, and perform light housework
• 4:  Climb one flight of stairs, walk on level ground at 4 mph, run for short distances, perform heavy housework, and play tennis or golf
• >10:  Performs aerobic activities, such as swimming, basketball, and skiing

Diagnostic Tests

Patients who are at high risk of an adverse cardiac event can often be identified with a history and physical exam. However, the cardiologist will conduct several additional tests to evaluate your health status. These include:

• Resting 12-Lead EKG – This is a non-invasive test that allows the doctor to evaluate your heart rhythm. It is recommended for patients with at least one clinical risk factor who are undergoing surgery.

• LV Function Evaluation – The cardiologist will evaluate your left ventricle functioning. This is done by echocardiogram or nuclear testing. Patients with shortness of press or a prior history of heart failure often need this screening.

• Stress Testing – One useful method to detect heart muscle ischemia and functional capacity is a stress test. This is indicated for patients with unstable angina, severe valvular disease, and heart failure. During this test, you will walk on a treadmill or receive medication that puts stress on your heart.

• Coronary Angiography – For patients who are at high risk for heart disease based on risk factors and non-invasive tests, the cardiologist uses a coronary angiograph to determine health status. This test uses special x-rays and dye to show the insides of the coronary arteries.

• Brain Natriuretic Peptide (BNP) – The BNP is a natural substance secreted from the lower chambers of the heart in response to pressure changes that occur with heart failure. The BNP test is predictive of a major adverse cardiac event following surgery. A result of below 100 pg/mL indicates no heart failure, whereas a level above that indicates the presence of this condition.

Resources

 

BMJ (2011):  http://bestpractice.bmj.com/best-practice/monograph/954.html

Fleisher LA et al. (2007). ACC/AHA Guideline. Circulation, 116: e418 – 3 500. Retrieved from: http://circ.ahajournals.org/content/116/17/e418.full