Evaluation of Appropriate Use of Preoperative Echocardiography Before Major Abdominal Surgery

A Retrospective Cohort Study

Allyson Tank, M.D.; Robert Hughey, M.D.; R. Parker Ward, M.D.; Peter Nagele, M.D., M.Sc.; Daniel S. Rubin, M.D., M.S.

Disclosures

Anesthesiology. 2021;135(5):854-863. 

In This Article

Discussion

In our retrospective cohort study, we found that while preoperative resting echocardiography was uncommon overall (6%), more than one in four echocardiograms (29%) that were classifiable by the Appropriate Use Criteria for Echocardiography were considered "rarely appropriate." The American College of Cardiology and American Heart Association perioperative practice guidelines recommend a narrow set of conditions for preoperative resting echocardiography known to be associated with increased perioperative complications.[2] An important and consistent theme throughout the practice guidelines is that cardiac testing should be rarely pursued in the absence of a clear indication independent of the impending surgery. The Appropriate Use Criteria for Echocardiography provide guidance to clinicians in the optimal use of resting echocardiography for all clinical settings and provide guidance to perioperative clinicians in appropriate use of resting echocardiography for conditions that may not directly apply to the perioperative period. The most frequent reason for "rarely appropriate" preoperative resting echocardiograms in our study was routine surveillance of known cardiovascular disease, such as chronic ischemic heart disease. Further, there was no difference in frequency of major adverse cardiac events among patients undergoing "rarely appropriate" as compared to "appropriate" or "unclassifiable" echocardiograms. These findings suggest that while overall preoperative resting echocardiography utilization is low, there still exists an opportunity to reduce testing that has not been shown to impact perioperative cardiac morbidity.

The high proportion of "rarely appropriate" echocardiograms may be secondary to the outpatient nature of the echocardiograms assessed in this study as well as ordering clinician characteristics. Outpatient studies are less likely to be associated with a change in clinical status and are known to have a higher frequency of "rarely appropriate" echocardiograms compared to inpatient exams. The frequency of "rarely appropriate" echocardiograms in other practice settings has been reported as high as 30%, which is similar to our findings.[13–15] In our sensitivity analysis of nonperioperative echocardiograms, we identified a high percentage of "rarely appropriate" echocardiograms in the outpatient setting, which suggests that potential overuse of cardiac imaging in the outpatient setting is not limited to the preoperative period. Ordering clinician characteristics may lead to a higher frequency of "rarely appropriate" echocardiograms in the preoperative setting. In a single academic center retrospective cohort of patients referred for outpatient transthoracic echocardiography, we demonstrated that anesthesia and surgical clinicians had the highest frequency of "rarely appropriate" echocardiograms (21% and 19%, respectively) as compared to cardiologists (3%) or internal medicine clinicians (10%).[16] This may be due to a lack of familiarity with the Appropriate Use Criteria for Echocardiography among anesthesia and surgical clinicians.[16] Anesthesiologists are required to address medical concerns during perioperative visits that extend beyond the upcoming procedure. As such, our specialty should consider incorporating the Appropriate Use Criteria for Echocardiography to guide preoperative cardiovascular imaging and develop interventions to reduce potential overuse. Our finding that a small number of diagnoses (e.g., surveillance of chronic ischemic heart disease) are associated with a large proportion of "rarely appropriate" echocardiograms may help to guide interventions that may be effective to decrease potential overuse of preoperative resting echocardiography.[13,17,18]

Chronic ischemic heart disease without change in clinical status accounted for just over a quarter of all the "rarely appropriate" echocardiograms in our study and may be an easy target to reduce overuse. In the only prospective trial across eight hospital systems to reduce "rarely appropriate" echocardiograms, the second most common reason for a "rarely appropriate" echocardiogram was routine surveillance of ventricular function with known coronary artery disease and no change in clinical status or cardiac examination.[17] The intervention for the trial comprised an initial video lecture, a mobile application-based decision support tool, and monthly clinician feedback reports for cardiologists and primary care providers that summarized individual ordering behavior. The proportion of rarely appropriate echocardiograms decreased in the intervention group as compared to the control (8.8% vs. 10.1%; odds ratio, 0.75; 95% CI, 0.57 to 0.99; P = 0.039), and the decrease was sustained throughout the study period.

Sex bias may have played a role in the higher frequency of men receiving a "rarely appropriate" echocardiogram as men may be more likely to receive cardiovascular testing. Previous population-based studies that evaluated utilization of perioperative resting echocardiograms similarly identified a higher frequency of testing in men as compared to women.[6] In a study of sex bias among cardiologists evaluating a simulated patient with suspected coronary artery disease, male patients were more consistently rated as likely to benefit from angiography as compared to female patients.[19] Given the known bias toward men and cardiovascular disease, it appears highly plausible that sex bias played a role with the increased frequency of "rarely appropriate" preoperative resting echocardiograms in our analysis.

Our study is timely in light of the Centers for Medicare and Medicaid Services mandate starting in 2022 that will require appropriateness determinations according to the Appropriate Use Criteria for Echocardiography to be submitted at the time of study order for all "advanced imaging procedures" for Medicare beneficiaries.[20] Clinicians will be tracked through the program, and those considered outliers with a high frequency of "rarely appropriate" studies will be subject to more rigorous authorizing procedures and potential reimbursement denials. Initially, perioperative physicians will experience this program in relation to preoperative nuclear stress testing as resting echocardiography is not included in the first phase of the mandate. However, as the highest volume cardiac imaging test performed, resting echocardiography is expected to be included as the program expands.[21] Further, perioperative testing is likely to be a particular focus and may be disproportionally affected by these programs. Our study addresses the knowledge gap of appropriate use criteria for resting echocardiography on a national level, and our finding of a high frequency of rarely appropriate studies suggests significant potential overuse. However, a full understanding of appropriate utilization of perioperative resting echocardiography also requires consideration of potential underuse when "appropriate" indications are present. In a study that used the National Inpatient Sample to identify "appropriate" use of inpatient resting echocardiography for certain conditions (e.g., acute myocardial infarction), only 8% of inpatient admissions received a resting echocardiogram.[22] Patients who received a resting echocardiogram had a lower inpatient mortality as compared to patients who did not when adjusting for patient and hospital characteristics. Given that there are a variety of appropriate indications unrelated to surgery that may first come to clinical attention in the perioperative setting (e.g., heart murmur), the potential for underuse of resting echocardiography is real. While our study did not address underuse, further study of this issue in the perioperative setting, and its association with patient outcomes, deserves study.

Our study has several limitations. First, the MarketScan databases only include patients with employer-sponsored health insurance or Medicare supplemental plans and may not be a representative sample of the U.S. population. This may explain why our frequency of preoperative echocardiograms was lower than other population-based studies that had higher mean ages for their cohorts. Thus, it remains unclear if our results are generalizable to a traditional Medicare population. MarketScan provides diagnosis and procedure codes for billing purposes, and these codes do not fully represent the scope of disease and may not capture clinical changes over time for each patient. Other unmeasured variables may have impacted the decision for preoperative echocardiography that we were unable to account for, and it is possible that the billing codes utilized did not appropriately reflect the clinical status of the patient. However, we used a robust approach to classify echocardiograms based on principal and secondary diagnoses that were directly matched to criteria found within the Appropriate Use Criteria for Echocardiography. Further, we did not identify any change in the frequency of "appropriate" echocardiograms across the transition from International Classification of Diseases, Ninth Revision–Clinical Modification to International Classification of Diseases, Tenth Revision–Clinical Modification coding that took place in 2015. In addition, our data collection focused on comorbidities that were documented in the year before surgery, which may not capture the full burden of comorbid disease for each patient. The Appropriate Use Criteria for Echocardiography rely much more heavily on consensus and expert opinion as compared to practice guidelines that rely heavily on a more evidence-based format.[23] However, the Appropriate Use Criteria for Echocardiography incorporate the preoperative cardiac evaluation practice guidelines with regards to their recommendations. Finally, the later years of the study cohort contained fewer patients as compared to earlier in the cohort, and this may have led to decreased precision in some of the later estimates of the frequency of "rarely appropriate" studies.

In conclusion, more than one in four classifiable resting preoperative echocardiograms before major abdominal surgical procedures may be considered "rarely appropriate" according to the Appropriate Use Criteria for Echocardiography. It is important to focus continued efforts on mitigating potential overuse of preoperative echocardiography, as unnecessary testing contributes to increased costs to patients and to the healthcare system.

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