Person:

Weinstein, Adam

Background. Preoperative anesthetic evaluations of patients before surgery traditionally involves assessment of a patient’s functional capacity to estimate perioperative risk of cardiovascular complications and need for further workup. This is typically done by inquiring about the patient’s physical activity, with the goal of providing an estimate of the metabolic equivalents (METs) that the patient can perform without signs of myocardial ischemia or cardiac failure. We sought to compare estimates of patients’ METs between preoperative assessment by medical history with quantified assessment of METs via the exercise cardiac stress test. Methods. A single-center retrospective chart review from 12/1/2005 to 5/31/2015 was performed on 492 patients who had preoperative evaluations with a cardiac stress test ordered by a perioperative anesthesiologist. Of those, a total of 170 charts were identified as having a preoperative evaluation note and an exercise cardiac stress test. The METs of the patient estimated by history and the METs quantified by the exercise cardiac stress test were compared using a Bland–Altman plot and Cohen’s kappa. Results. Exercise cardiac stress test quantified METs were on average 3.3 METS higher than the METs estimated by the preoperative evaluation history. Only 9% of patients had lower METs quantified by the cardiac stress test than by history. Conclusions. The METs of a patient estimated by preoperative history often underestimates the METs measured by exercise stress testing. This demonstrates that the preoperative assessments of patients’ METs are often conservative which errs on the side of patient safety as it lowers the threshold for deciding to order further cardiac stress testing for screening for ischemia or cardiac failure.

Background The role of anesthesiologists has expanded from operating rooms to preoperative evaluation clinics. This role involves performing preoperative cardiovascular evaluation and optimization of patients before elective surgery, which can include ordering cardiac stress tests. We aimed to study the ordering patterns by anesthesiologists for preoperative cardiac stress tests, focusing on whether societal and institutional guidelines and recommendations were used. Choice of type of cardiac stress test was also examined.

Methods A single center retrospective chart review from December 1, 2005 to May 31, 2015 was performed on 492 patients who had a cardiac stress test ordered by an anesthesiologist. Patients were categorized by indication for ordering the cardiac stress test based on societal practice guidelines, institutional guidelines or other relevant reasons at the time of patient encounter. Those “other” category cardiac stress tests were assessed for indication and evaluated by physician peer review to see if there was peer agreement for being appropriately ordered. Exercise electrocardiography (ECG) cardiac stress tests ordered were evaluated for appropriateness based on baseline resting ECG findings. Patients with left bundle branch block (LBBB) or right ventricular (RV) pacing were evaluated for appropriateness of proper cardiac stress test modality based on whether a pharmacological vasodilator cardiac stress test was ordered.

Results Analysis of the cardiac stress tests ordered showed that 43% were ordered according to American College of Cardiology/American Heart Association guidelines, 29% were ordered according to institutional guidelines, and 28% were categorized as “other”. Of the 28% “other” cardiac stress tests, 53% were in agreement for ordering by peer review. Sixty-four exercise ECG cardiac stress tests were ordered, of which 58% were appropriate based on having no baseline resting ECG abnormalities. Fifty-one patients were identified as having a resting ECG of LBBB or RV pacing of which 41% had an appropriate pharmacological vasodilator cardiac stress tests ordered.

Conclusions Anesthesiologists order most preoperative cardiac stress tests according to professional societal or institutional guidelines (72%), yet they are not always choosing the best modality of cardiac stress test. A significant portion of cardiac stress tests are ordered (28%) based on clinical judgment, likely due to the lack of guidelines and recommendations being all-encompassing on many commonly encountered preoperative patient situations.