The authors prospectively studied 455 consecutive patients referred to the general medical consultation service for cardiac risk assessment prior to non-cardiac surgery, in order to validate a previously derived multifactorial index in their clinical setting. They also tested a version of the index that they had modified to reflect factors they believed to be important. For patients undergoing major surgery, the original index performed less well in the validation data set than in the original derivation set (p less than 0.05), but still added predictive information to a statistically significant degree (p less than 0.05). The modified index also added predictive information for patients undergoing both major and minor surgery, demonstrating an area under the Receiver Operating Characteristic curve of 0.75 (95% confidence interval of 0.70 to 0.80). A simple nomogram is presented which will enable conversion of pretest probabilities into posttest probabilities using the likelihood ratios associated with each risk score. It is recommended that clinicians estimate local overall complication rates (pretest probabilities) for the clinically relevant populations in their settings before they apply the predictive properties (likelihood ratios) demonstrated in this study in order to calculate cardiac risks for individual patients (posttest probabilities).

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In the treatment of small AVMs, surgery confers a large clinical benefit over SR. The reason is that surgery protects the patient from hemorrhage earlier and with greater success than does SR. The associated cost-effectiveness ratio, $7100/QALY, is highly economically attractive. Therefore, surgery achieves important improvements in clinical outcomes and is associated with an excellent ratio of incremental costs per QALY gained.

Quick Medical Reference may be a useful adjunct to interns in formulating diagnostic strategies for difficult clinical cases. However, since optimal conditions were chosen for QMR benefit in this study design, the small benefit in test scores must be weighed against the time required to teach QMR to interns.