May 29, 2001

The Cardiac Anesthesia Risk Evaluation Score: A clinically useful predictor of mortality and morbidity after cardiac surgery

Dupuis J-Y, Wang F, Nathan H, Lam M, Grimes S, Bourke M. Anesthesiology 2001;91:194-204.

Commentary by Katherine Grichnik

This is an article about a very useful proposal for a new system to easily evaluate what the risk is for a perioperative morbid or mortal event surrounding a cardiac surgical procedure. This clinically based risk score is called the CARE score—"The Cardiac Anesthesia Risk Evaluation".

The impetus to devise and test a new risk score was born from the observation that previously published scores are cumbersome to use and that anesthesiologists are good as assessing clinical risk. It was also noted that a large amount of prognostic information could be obtained from just a few clinical variables or by clinical judgment alone.

Thus, this clinical risk score includes clinical judgment with 3 risk factors previously identified by multifactorial risk indexes: 1) comorbid conditions which are controlled or uncontrolled, 2) the surgical complexity of the case, and 3) the urgency of the procedure.

Using the CARE score, the authors hypothesized that:

1. It would be a valid predictor of outcome after cardiac surgery
2. That it would compare well to previously published risk scores and
3. It would be easily and reproducibly integrated into practice by clinicians. The authors studied 1548 patients using the CARE score. The outcomes studied were in hospital mortality and morbidity (divided into cardiac, respiratory, neurological, renal, infectious and other categories). Prolonged LOS was also noted.

CARE RISK SCORE (by Dupis, et al)

1. Patient with stable cardiac disease and no other medical problem. Noncomplex surgery
2. Patient with stable cardiac disease and one or more stable medical problems. Noncomplex surgery
3. Patient with any uncontrolled medical problem OR a complex surgery
4. Patient with chronic or advanced cardiac disease for whom cardiac surgery is undertaken as a last hope to save or improve life.
5. Emergency: surgery as soon as diagnosis is made and OR is available
   
   

Examples of controlled medical problems: hypertension, diabetes, peripheral vascular disease, chronic obstructive pulmonary disease.

Example of uncontrolled medical problems: unstable angina with intravenous heparin or nitroglycerin, preoperative intraaortic balloon pump, congestive heart failure with edema, uncontrolled hypertension, renal insufficiency.

Examples of complex operations: reoperation, combined valve and coronary artery surgery, multiple valve surgery, post myocardial infarction VSD repair, coronary surgery with heavily calcified or diffuse coronary artery disease.

The authors found that the CARE score is indeed an accurate predictor of mortality and morbidity after cardiac surgery, which compared well with the previously published Parnsonnet, Tuman and Tu scores. Further, experienced clinicians were easily able to integrate the score into their practice in a consistent and relevant manner. It was noted that these previously published scores were difficult to memorize and integrate as compared to the CARE score, which more closely resembles the familiar ASA classification.

This article is accompanied by an editorial by Lee Fleisher. He asks the question "What is the additive value of a particular risk index above simple clinical judgment for both the clinician and the patient?" He notes that risk indices are and should be used to identify important risk factors that could be targets for intervention and are used to compare groups of patients in outcomes research. However, he also opines that such indices are not necessary for perioperative care or patient education, as a "number" from a risk index does not provide the anesthesiologist with the information that he or she needs to modify care. He does note that such an index may be useful to non-anesthesia related medical personnel to stratify risk in order to make an intervention at a certain risk level.

As a clinician and educator, I believe that this risk index is very interesting and potentially very useful. In this setting, it can be used to 1) preoperatively identify the high risk patient, 2) potentially modify care perioperatively, 3) alert family members to the probability of perioperative morbidity or mortality and to 4) educate our residents/fellows about what situations and patient factors create the potential for perioperative morbidity and mortality. This sort of an index is only useful for education, however, if anesthesiologist assumes the role of a perioperative physician and follows the outcomes of their patients postoperatively. I encourage anesthesiologists caring for cardiac surgical patients to try this risk score and assess its usefulness in predicting postoperative outcomes in your patient population.

ABSTRACT

The Cardiac Anesthesia Risk Evaluation Score: A Clinically Useful Predictor of Mortality and Morbidity after Cardiac Surgery

AUTHORS: Dupuis J-Y, Wang F, Nathan H, Lam M, Grimes S, Bourke M

SOURCE: Anesthesiology 2001;91:194-204

ABSTRACT: No abstract available