Perioperative Evaluation for Noncardiac Surgery

AHA/ACC Guidelines

The most authoritative guidelines are from the AHA/ACC and they have a very useful website aimed at educating physicians. Check out the following features:

- The guidelines are available online or as a PDF file

- Teaching slides - you can view them online or download the PowerPoint file

- Download the Pocket PC version

You can check out the other guidelines available from AHA/ACC here. All files are free downloads.


Perioperative Guidelines for PDA

You have to download the Pocket PC (or Palm) version from Skyscape. The downloaded file is the standard installer, used by the other Skyscape applications, like Archimedes.

The universal algorithm makes the preoperative evaluation a breeze. It guides you step-by-step, using a simple question and answer approach, simplifying the process. You can bookmark the most commonly used parts of the guidelines like:

- conditions-predictors of cardiovascular risk in different patients - high, intermediate and low risk

- calculating the METs (metabolic equivalents, i.e. energy requirement for various activities)

- levels of risks for different surgical procedures - high, intermediate and low

- the main step-by-step algorithm


"PASS" the Preoperative Evaluation

There are 4 variables in the preoperative evaluation, remembered by the mnemonic PASS:

Patient risk
Activity level - measured in METs
Surgical risk
Select the tests to perform

1. Patient risk - a patient with CAD S/P CABG with CHF is clearly at a higher risk than a patient who has only HTN.

2. How well is the patient prepared for surgery? What is his activity level (measured in METs)? The most useful question is "do you have stairs in your house?". If yes, "can you climb a flight of stairs without SOB or CP?" Going up and down stairs will give the patient a MET of 4, which is the dividing point in the algorithm to consider cardiac testing. Just remember "stairs = MET 4".

3. Surgical risk - a high risk procedure, like AAA repair vs. a low risk procedure, like breast biopsy.

4. Select the tests to perform. EKG is almost always indicated. Follow the algorithm to decide which patient needs a stress test.

After you look into these 4 variables (PASS), you have to follow the AHA/ACC algorithm. Of course, there are many other things to address, like when to stop and restart certain medications, etc. This is the basic approach which is the backbone of the perioperative evaluation.


Three Stress Tests

Choose one of the 3 stress test modalities. The mnemonic is EDD:

- Exercise stress testing - without imaging or pharmacologic induction (both are used in the other 2 stress tests below)
- Dipyridamole-thallium imaging (DTI)
- Dobutamine stress echo (DSE)

Exercise stress testing limitations:
- OA patient who is unable to exercise
- Resting EKG abnormalities

DTI prognostic accuracy is 81%.

DSE has the additional advantage of showing the systolic function, the accuracy is similar to DTI.


Cut-off Numbers in the Algorithm

Remember the cut-off numbers 2-4-5 in the algorithm:
- 2 years of the last catheterization or a stress test - safe to proceed with surgery, if no symptoms
- 4 METs
- 5 years of the last coronary revascularization - safe to proceed with surgery, if no symptoms


Take the "HIP" Shortcut

The majority of patients have intermediate or minor clinical predictors, and you can use the following shortcut to determine who needs a stress test.

The shortcut to noninvasive testing is remembered by the mnemonic HIP:

- High risk surgery - vascular surgery
- Intermediate clinical predictors - old MI, DM 2
- Poor functional class

If a patient has 2 out of 3 of the above variables, he or she will need a stress test before the surgery.

Note: The "HIP" shortcut is valid for patients who are scheduled to have high risk or intermediate risk surgery. Patients scheduled for low risk surgery can usually proceed with the operation without the need to have a stress test first.


The Cleveland Clinic Perioperaive Medicine Summit

The summit, conducted on September 22-23, 2005 included more than 200 physicians, and was a resounding success.

Summit directors were Dr. Jaffer and Dr. Michota. Several members of the hospitalist team presented lectures and case discussions during the two-day event.

Proceedings of the Perioperative Medicine Summit were published in a special supplement of the Cleveland Clinic Journal of Medicine.


Reference:
AHA/ACC Clinical Statements/Guidelines
Online Calculator - MedCalc: Perioperative Cardiac Evaluation
Patient Education: PreOp.com
Using beta-blockers to cut perioperative risk in CAD. Postgraduate Medicine, 12/05.
Image source: Wikipedia, CCF (used with permission)