Background
The aim of this study was to compare appropriateness designations as determined by the updated 2011 appropriate use criteria (AUC) for echocardiography with prior versions of the AUC for transthoracic echocardiographic (TTE) imaging, transesophageal echocardiographic (TEE) imaging, and stress echocardiographic (SE) imaging. An additional goal was to define relationships between appropriateness determinations and echocardiographic findings for each modality.
Methods
Previously published data sets of TTE, TEE, and SE studies were reclassified according to the 2011 AUC, and indication representation, appropriateness designations, and echocardiographic findings were compared with prior classifications according to the 2007 AUC for TTE and TEE imaging and the 2008 AUC for SE imaging.
Results
Overall, 2,247 echocardiographic studies were analyzed. The 2011 AUC addressed the vast majority of studies (98%), a marked increase compared with prior versions of the AUC (89%) ( P < .001). An increase in addressed studies was present in each echocardiographic modality (TTE imaging: n = 1,525, 98% vs 89%, P < .001; TEE imaging: n = 405, 99.7% vs 91%, P < .01; SE imaging: n = 289, 97% vs 88%, P < .01). Among all echocardiographic procedures, the 2011 AUC found a lower frequency of appropriate studies compared with prior AUC (82% vs 88%, P < .01), primarily because of new uncertain indications for TTE imaging. The frequency of inappropriate echocardiographic studies was unchanged (11%). Among all echocardiographic procedures, the 2011 AUC found appropriate studies to have more new abnormal echocardiographic findings compared with inappropriate studies (45% vs 13%, P < .001). Interestingly, 2011 AUC inappropriate TTE studies had fewer major new echocardiographic abnormalities than 2007 AUC inappropriate TTE studies (9% vs 17%, P = .04).
Conclusions
The updated 2011 AUC for echocardiography encompass the vast majority of echocardiographic procedures in a university hospital practice, filling virtually all of the gaps identified in prior versions of the AUC for TTE, TEE, and SE imaging. The 2011 AUC also reasonably stratify the likelihood of finding an echocardiographic abnormality, demonstrating improvement compared with the prior AUC.
Over the past decade, health care expenditures on cardiac imaging have grown at a faster rate than for other medical services. As a result, there has been increased scrutiny on the use, and potential overuse, of cardiac imaging procedures. In response to this scrutiny, the American College of Cardiology, in conjunction with other imaging societies including the American Society of Echocardiography (ASE), have published appropriate use criteria (AUC) to help guide the use of cardiac imaging procedures in the delivery of high-quality medical care. Among the first were the 2007 AUC for transthoracic echocardiographic (TTE) imaging and transesophageal echocardiographic (TEE) imaging and the 2008 AUC for stress echocardiographic (SE) imaging.
After the publication of these documents, a number of investigations evaluated the implementation of the AUC for TTE, TEE, and SE imaging in clinical practice. Although generally high rates of appropriate utilization of echocardiographic procedures were found, important gaps were identified, resulting in incomplete representation of the broad practice of echocardiography. Concerning inconsistencies, such as a high rate of echocardiographic abnormalities on studies deemed to be inappropriate by the AUC, were also noted. These issues tempered enthusiasm for widespread implementation of the initial versions of the AUC for echocardiography.
To address these concerns, the American College of Cardiology and partner societies have recently published the updated 2011 AUC for echocardiography, which address TTE, TEE, and SE imaging. Initial studies suggest that the 2011 AUC fill many of gaps for the practice of TTE imaging, though there have been some discrepancies in these cohorts, and they have been focused almost exclusively on TTE imaging, with no studies to date addressing SE imaging. The goal of this study was to compare clinical application of the 2011 AUC for echocardiography to the prior 2007 AUC for TTE and TEE imaging and the 2008 AUC for SE imaging, including appropriateness determinations and echocardiographic findings.
Methods
Previously published data sets of consecutively performed TTE studies (July to September 2007), TEE studies (July 2007 to February 2008), and SE studies (May to December 2008) were reclassified according to the 2011 AUC for echocardiography. All testing was completed at the University of Chicago Medical Center. As previously described, at the time of initial data collection, patient demographics, specialty of ordering provider, inpatient versus outpatient status, clinical details obtained from written echocardiography requisitions and electronic medical records, and relevant prior imaging studies were entered into a database. In addition, the echocardiographic findings for each study were recorded. The protocol was approved by the institutional review board, and all patients provided informed consent.
Indication Determination
The classification of studies according to the 2011 AUC was performed with identical methodology as outlined in the original publications for TTE, TEE, and SE imaging. Two investigators, blinded to the prior AUC indication and appropriateness determination and to the echocardiographic results, independently reviewed all relevant clinical data for each study and selected the 2011 AUC indication number (1–200) that best fit the clinical reason the study was ordered or determined that it was not addressed by any of the 2011 AUC indications. A primary consensus indication for each study was then determined. For studies in which the two investigators selected an identical indication number or both selected “not addressed,” that indication or “not addressed” served as the final consensus indication. For studies for which there was not agreement between the two investigators, a third investigator independently reviewed the data and selected one of the initial two selections as the final primary consensus indication. According to the primary consensus indication, each study was categorized as appropriate, inappropriate, uncertain, or not addressed, according to the 2011 AUC for echocardiography. The appropriateness classifications and their relationships to the echocardiographic findings were then compared with our previously published appropriateness classifications according to the 2007 AUC for TTE and TEE imaging and the 2008 AUC for SE imaging. The 2007 TTE and TEE AUC and the 2008 SE AUC classifications used for this comparison were the original classifications performed at the time of the prior studies.
Echocardiographic Procedures
All TEE, TTE, and SE studies were performed and interpreted in accordance with the preferred recommendations of the ASE, as is standard in our laboratory. All studies were performed using a full-platform echocardiographic instrument (iE33; Philips Medical Systems, Andover, MA), as described previously. All TTE studies were complete two-dimensional, color Doppler, and tissue Doppler studies. All TEE studies were acquired using omniplane transducers (range, 4–7 MHz). SE was either exercise or pharmacologic, as previously described. Exercise testing consisted of symptom-limited exercise treadmill testing using a Bruce protocol, with baseline and peak stress imaging. Pharmacologic testing was performed with dobutamine using a standard rest, low-dose (5–10 μg/kg/min), high-dose (20–50 μg/kg/min), and recovery imaging protocol, with atropine supplementation (up to 1 mg) if necessary to achieve 85% of the maximum predicted heart rate response.
All echocardiographic studies were interpreted at the time of clinical exam by expert echocardiographers blinded to the appropriateness designation of the study, and the findings used for analysis in this study represent those reported on the final clinical echocardiographic report.
TTE Findings
TTE findings and definitions are all as previously published. As is standard in our laboratory, left ventricular (LV) function was assessed using visual or quantitative methods and ASE-recommended definitions for LV dysfunction (LV ejection fraction [LVEF] ≤ 54%), moderate LV dysfunction (LVEF, 30%–44%), and severe LV dysfunction (LVEF < 30%) were used. The severity of valvular heart disease was determined using a combination of expert visual opinion and the preferred quantitative methodology and definitions of the ASE. Right ventricular systolic function was determined by expert visualization. Regional wall motion abnormalities were determined by expert opinion and defined as hypokinesis, akinesis, or dyskinesis reported in any of the 17 myocardial segments. The presence of pulmonary hypertension was defined as an estimated right ventricular systolic pressure ≥ 35 mm Hg, as determined from the maximum tricuspid regurgitation velocity and estimated right atrial pressure (standard value, 10 mm Hg). Moderate or greater pulmonary hypertension was defined as an estimated right ventricular systolic pressure ≥ 50 mm Hg. Diastolic dysfunction was determined on the basis of expert review of mitral, pulmonary, and tissue Doppler data and is reported as mild (impaired relaxation, grade I), moderate (impaired relaxation with moderately elevated filling pressures or “pseudonormal,” grade II), or severe (impaired relaxation with marked elevation of filling pressures, grade III or IV).
A composite end point of “any TTE abnormality” was defined as LV dysfunction (LVEF ≤ 54%); aortic stenosis (aortic valve area < 1.5 cm 2 ); a regional wall motion abnormality; right ventricular dysfunction; any pulmonary hypertension; mild or greater mitral, aortic, or tricuspid regurgitation; diastolic dysfunction; or other significant abnormality (mitral stenosis [mitral valve area < 1.5 cm 2 ], moderate or greater pulmonary valve regurgitation, moderate or greater pericardial effusion, or any other significant abnormality, such as thrombus, vegetation, or tumor). A “major TTE abnormality” was defined as moderate or greater LV dysfunction (LVEF < 45%); moderate or greater mitral, aortic, or tricuspid regurgitation; aortic stenosis (aortic valve area < 1.5 cm 2 ); a regional wall motion abnormality; right ventricular dysfunction; moderate or greater pulmonary hypertension; moderate or severe diastolic dysfunction; or other significant abnormality (mitral stenosis [mitral valve area < 1.5 cm 2 ], moderate or greater pulmonary valve regurgitation, moderate or greater pericardial effusion, or any other significant abnormality, such as thrombus, vegetation, or tumor).
For every patient with a prior TTE study at our institution, the current TTE findings were compared with those of the prior study. A “new TTE abnormality” and a “new major TTE abnormality” were defined, respectively, as “any TTE abnormality” or “any major TTE abnormality” that was not previously known or in which there had been a change of at least one severity grade from a prior TTE study (i.e., previously mild LV dysfunction, now moderate LV dysfunction).
SE Clinical Findings
An “SE abnormality” was defined, as previously described, as any echocardiographic finding suggesting inducible myocardial ischemia, including any new stress-induced wall motion abnormality, stress-induced worsening of an existing wall motion abnormality, and/or stress induced LV dysfunction or chamber enlargement.
TEE Finding
As previously described, TEE abnormalities included all those deemed to be TTE abnormalities, in addition to “abnormalities not typically seen on TTE imaging,” defined as right or left atrial mass or thrombi, interatrial shunt, atrial septal defect, spontaneous echogenicity in the left atrium, valvular masses or vegetations, moderate or greater ascending or descending aortic or aortic arch dilation, complex aortic atheromatous disease (plaque in the ascending or descending aorta or aortic arch that protruded >4 mm into aortic lumen or was associated with ulceration or mobile features), aortic dissection, aortic ulcer or intramural hematoma, prosthetic valve abnormalities, and primary valve leaflet abnormalities other than mitral valve prolapse (flail leaflet, torn chordae, and leaflet perforation). A “new TEE abnormality” was defined as any TEE abnormality that had not been seen on a prior TTE study (if TEE imaging had been an adjunctive study) or any “abnormalities not typically seen on TTE imaging” (if the TEE study was the initial echocardiographic study).
We additionally assessed the relationship between appropriateness determinations for TEE imaging according to the 2011 AUC and the influence of the TEE findings on patient management. As previously reported, the impact of TEE findings on patient management could be determined in 85% of TEE studies ( n = 344). As defined previously, a TEE result that “influenced medical decision making” was defined as any TEE result that directly led to a change in patient management or clinical decision making and thus was found to directly influence the medical care of the patient. Examples of this included any TEE result that influenced a decision for medical versus surgical versus no therapy, anticoagulation, cardioversion versus rate control, choice and duration of antimicrobial therapy, and/or prompting of additional testing or imaging.
Statistical Analysis
Comparisons between study and patient characteristics, and between levels of appropriateness determination and echocardiographic findings, were performed using χ 2 tests or Fisher’s exact tests for categorical data as appropriate and Student’s t test for continuous data using a two-tailed P value < .05 for statistical significance. Interobserver variability in the determination of indication and category and overall level of appropriateness is expressed as a percentage of agreement between the two independent reviewers. For indication and category determination, interobserver comparisons represent the frequency with which the reviewers agreed on the indication number or category (i.e., indications #1–200 in the 2011 AUC, or “not addressed”). For the determination of overall level of appropriateness, interobserver comparisons represent the frequency with which reviewers selected indications with matching levels of appropriateness (appropriate vs inappropriate vs uncertain), though not necessarily an identical indication number. Studies for which both reviewers chose “not addressed,” so that no appropriateness level was available for either reviewer selection, were excluded from appropriateness level comparisons.
Results
Overall, 2,247 echocardiographic studies were analyzed, including 1,553 transthoracic, 405 transesophageal, and 289 stress studies. The mean age of all patients was 59 ± 17 years, 52% ( n = 1,158) of all studies were performed on women, and 52% of all studies were performed on outpatients (51% outpatient TTE studies, 28% outpatient TEE studies, and 93% outpatient SE studies). Overall, 50% of studies ( n = 1,117) were ordered by cardiac specialists (i.e., cardiologists or cardiac surgeons), while 34% ( n = 754) were ordered by internal medicine or primary care physicians.
The 2011 AUC addressed the vast majority (98% [ n = 2,210]) of all studies, a marked increase compared with the combined representation of the 2007 AUC for TTE and TEE imaging and the 2008 AUC for SE imaging (89% [ n = 2,006]) ( P < .001). This increase in representation was significant for each echocardiographic modality (TTE imaging: 98% vs 89%, P < .001; TEE imaging: 99.8% vs 91%, P < .01; SE imaging: 97% vs 88%, P < .01). For TTE imaging, there was a significant increase in the number of addressed studies in both inpatients and outpatients ( Table 1 ). Differences between inpatients and outpatients were not analyzed for TEE and SE studies, because of the small number of outpatient TEE and inpatient SE studies.
| Modality | Updated 2011 AUC | Prior AUC | P |
|---|---|---|---|
| All studies ( n = 2,247) | |||
| Addressed | 98% (2210) | 89% (2006) | <.001 |
| TTE imaging ( n = 1,553) | |||
| Addressed | 98% (1525) | 89% (1385) | <.001 |
| Appropriate ∗ | 82% (1253) | 89% (1228) | <.001 |
| Inappropriate ∗ | 11% (162) | 11% (157) | NS |
| Uncertain ∗ | 7% (110) | None listed | |
| Outpatient ( n = 792) | |||
| Addressed | 97% (781) | 85% (670) | <.001 |
| Appropriate ∗ | 74% (579) | 82% (549) | <.001 |
| Inappropriate ∗ | 16% (125) | 18% (121) | NS |
| Uncertain ∗ | 10% (77) | None listed | |
| Inpatient ( n = 761) | |||
| Addressed | 98% (749) | 94% (715) | <.01 |
| Appropriate ∗ | 91% (679) | 95% (679) | <.01 |
| Inappropriate ∗ | 5% (37) † | 5% (36) | NS |
| Uncertain ∗ | 4% (33) | None listed | |
| TEE imaging ( n = 405) | |||
| Addressed | 99.8% (404) | 91% (368) | <.001 |
| Appropriate ∗ | 95% (382) | 97% (358) | NS |
| Inappropriate ∗ | 3% (15) | 1% (3) | NS |
| Uncertain ∗ | 2% (7) | 2% (7) | NS |
| SE imaging ( n = 289) | |||
| Addressed | 97% (281) | 88% (253) | <.001 |
| Appropriate ∗ | 59% (165) | 71%(180) | <.01 |
| Inappropriate ∗ | 22% (64) | 20% (50) | NS |
| Uncertain ∗ | 18% (52) | 9% (23) | NS |
∗ Percentage of addressed studies for each echocardiographic modality.
† P < .001 compared with inappropriate outpatient TTE studies.
Among addressed TTE studies, the 2011 AUC found a lower rate of appropriate studies compared with the 2007 AUC for TTE and TEE imaging (82% vs 89%, P < .001), a similar rate of inappropriate studies (11% vs 11%, P = NS), and 7% uncertain studies (the 2007 AUC list no uncertain indications for TTE imaging; Table 1 ). Similar to the 2007 AUC, when classified by the 2011 AUC, inpatient TTE studies were less likely to be inappropriate than outpatient TTE studies (5% vs 16%, P < .001). Among the addressed TEE studies, the 2011 AUC found similar rates of appropriate, inappropriate, and uncertain studies compared with the 2007 AUC for TTE and TEE imaging (appropriate: 95% vs 97%, P = NS; inappropriate: 3% vs 1%, P = NS; uncertain: 2% vs 2%, P = NS). Among addressed SE studies, the 2011 AUC found fewer appropriate studies compared with the 2008 AUC for SE (59% vs 71%, P < .01), with nonsignificant increases in inappropriate (22% vs 20%, P = NS) and uncertain studies (18% vs 9%, P = NS) compared with the 2008 AUC for SE imaging.
Overall, studies that were not addressed in the 2007 AUC for TTE and TEE imaging or the 2008 AUC for SE imaging ( n = 241) were most likely to be reclassified in the 2011 AUC as uncertain (36% [ n = 86]), with 25% ( n = 60) reclassified as appropriate and 25% ( n = 60) as inappropriate ( Table 2 ). Among TTE studies not addressed by the 2007 AUC (n=168), reclassification by the 2011 AUC to uncertain was most common (45% [ n = 76]), followed by reclassification to appropriate (19% [ n = 32]) and inappropriate (19% [ n = 32]). Among TEE studies not addressed by the 2007 AUC ( n = 37), a majority were reclassified by the 2011 AUC to appropriate (59% [ n = 22]), followed by inappropriate (32% [ n = 12]), and uncertain (5% [ n = 2]). Among SE studies not addressed by the 2008 AUC ( n = 36), reclassification to inappropriate (44% [ n = 16]) by the 2011 AUC was most common, followed by uncertain (22% [ n = 8]) and appropriate (17% [ n = 6]).
| Modality | 2011 AUC classification | |||
|---|---|---|---|---|
| Appropriate | Inappropriate | Uncertain | NA | |
| TTE imaging | ||||
| 2007 NA studies ( n = 168) | 19% (32) ∗ | 19% (32) ∗ | 45% (76) ∗ | 17% (28) |
| 2007 appropriate studies ( n = 1,228) | 98% (1206) | 0 | 2% (22) † | 0 |
| 2007 inappropriate studies ( n = 157) | 9% (15) ‡ | 83% (130) | 8% (12) § | 0 |
| TEE imaging | ||||
| 2007 NA studies ( n = 37) | 60% (22) ∗ | 32% (12) ∗ | 5% (2) ∗ | 3% (1) |
| 2007 appropriate studies ( n = 358) | 100% (358) | 0 | 0 | 0 |
| 2007 inappropriate studies ( n = 3) | 0 | 100% (3) | 0 | 0 |
| 2007 uncertain studies ( n = 7) | 29% (2) || | 0 | 71% (5) | 0 |
| SE imaging | ||||
| 2008 NA studies ( n = 36) | 17% (6) ∗ | 44% (16) ∗ | 22% (8) ∗ | 17% (6) |
| 2008 appropriate studies ( n = 180) | 88% (159) | 0 | 12% (21) ¶ | 0 |
| 2008 inappropriate studies ( n = 50) | 0 | 100% (50) | 0 | 0 |
| 2008 uncertain studies ( n = 23) | 0 | 0 | 100% (23) | 0 |
∗ For studies NA in the 2007 or 2008 AUC, the most common reclassified 2011 AUC indications are listed in Table 3 .
† Most common reclassified 2011 AUC indication: #72 “reevaluation of known heart failure (systolic or diastolic) with a change in clinical status or cardiac exam with a clear precipitating change in medication or diet.”
‡ Most common reclassified 2011 AUC indication: #73 “reevaluation of known heart failure (systolic or diastolic) to guide therapy.”
§ Most common reclassified 2011 AUC indication: #69: “reevaluation of known hypertensive heart disease without a change in clinical status or cardiac exam.”
|| Most common reclassified 2011 AUC indication: #109 “evaluation for cardiovascular source of embolus with no identified non-cardiac source.”
¶ Most common reclassified 2011 AUC indication: #157 “intermediate risk non-cardiac surgery: ≥ 1 clinical risk factor, poor or unknown functional capacity (<4 METs).”
For TTE imaging, the new 2011 AUC indications for studies previously not addressed were primarily related to imaging before or after organ transplantation programs, routine preoperative TTE imaging before noncardiac surgery, surveillance of patients with prior diagnoses of congestive heart failure, and surveillance of valvular heart disease in patients without changes in clinical status or new symptoms ( Table 3 ). For TEE imaging, the most common new indications for studies previously not addressed were for evaluation of cardiac source of embolus when no other noncardiac source has been identified and routine use of TEE imaging when TTE imaging would be expected to answer the clinical question. For SE imaging, new indications for studies previously not addressed included preoperative risk assessment, evaluation of syncope, and evaluation of ventricular ectopy or arrhythmias.
| Modality | Indication as listed in the 2011 AUC | % ( n ) of NA studies in prior AUC | Appropriateness classification |
|---|---|---|---|
| TTE imaging ( n = 168) | #14: “Routine perioperative evaluation of cardiac structure and function prior to non-cardiac solid organ transplant” | 27% (45) | Uncertain |
| #13: “Routine perioperative evaluation of ventricular function with no symptoms or signs of cardiovascular disease” | 10% (17) | Inappropriate | |
| #84: “Monitoring for rejection in a cardiac transplant recipient” | 9% (15) | Appropriate | |
| #75: “Routine surveillance (≥1 year) of heart failure when there is no change in clinical status” | 8% (14) | Uncertain | |
| #73: “Reevaluation of known heart failure (systolic or diastolic) to guide therapy” | 4% (7) | Appropriate | |
| #39: “Routine surveillance (≥3 years) of mild valvular stenosis without a change in clinical status or cardiac exam” | 3% (5) | Appropriate | |
| #38: “Routine surveillance (<3 years) of mild valvular stenosis without a change in clinical status or cardiac exam” | 3% (5) | Inappropriate | |
| #44: “Routine surveillance (≥3 years) of mild valvular regurgitation without a change in clinical status or cardiac exam” | 3% (5) | Uncertain | |
| TEE imaging ( n = 37) | #109: “Evaluation of cardiovascular source of embolus with no identified non-cardiac source” | 49% (18) | Appropriate |
| #100: “Routine use of TEE when a diagnostic TTE is reasonably anticipated to resolve all diagnostic and management concerns” | 32% (12) | Inappropriate | |
| SE imaging ( n = 36) | #154: “Low-risk non-cardiac surgery: perioperative evaluation for risk assessment” | 17%(6) | Inappropriate |
| #155: “Intermediate non-cardiac surgery: moderate to good functional capacity (≥ 4 METs)” | 14% (5) | Uncertain | |
| #133: “Syncope: low global CAD risk” | 9% (3) | Inappropriate | |
| #130: “Frequent PVCs, exercise induced VT, or non-sustained VT” | 6% (2) | Appropriate |
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