Background
A recent American College of Cardiology Foundation and American Society of Echocardiography document updated previous appropriate use criteria (AUC) for echocardiography. The aim of this study was to explore the application of the new AUC, and the resulting appropriateness rate, in hospitalized patients referred for transthoracic echocardiography (TTE) in a community setting.
Methods
A total of 931 consecutive inpatients referred for TTE were prospectively recruited in five community hospitals. Patients were categorized as having appropriate, uncertain, or inappropriate indications for TTE according to the AUC. An additional group of 259 inpatients, discharged without having been referred for TTE, was also considered.
Results
In the group referred for TTE, the large majority of indications (98.8%) were classifiable according to the AUC with good interobserver reproducibility. Indications were appropriate in 739 patients (80.3%), of uncertain appropriateness in 46 (5.0%), and inappropriate in 135 (14.7%). Compared with patients with appropriate or uncertain indications, those with inappropriate indications were younger and more often referred by noncardiologists. Most common causes of inappropriate indications were related to the lack of changes in clinical status or to the absence of cardiovascular symptoms and signs. Examinations with appropriate or uncertain indications had an impact on clinical decision making more often than those with inappropriate indications (86.7% vs 14.1%, P < .0001). In the group discharged without having been referred for TTE, TTE might have been appropriate in 16.2% of cases.
Conclusions
Clinical application of the new AUC was highly feasible in a community setting. Although inpatient referral for TTE was appropriate in most patients, strategies aimed at implementing these criteria in clinical practice are desirable.
Over the past two decades, there has been a sustained increase in the diagnostic use of transthoracic echocardiography (TTE). The possibility to obtain a large amount of diagnostic information using a noninvasive, low-cost diagnostic tool, together with continuous technical improvement and widespread availability of ultrasound systems, has contributed to the progressive advance of TTE in clinical practice. However, this growing role in the clinical scenario has been paralleled by concerns about potential overuse or misuse of TTE and by the problem of how to best incorporate its applications into daily clinical care using appropriate criteria. Accordingly, the American College of Cardiology, the American Society of Echocardiography, and the American Heart Association, in conjunction with other scientific societies, recently published an update of appropriateness use criteria (AUC) for echocardiography to establish criteria able to reflect new clinical evidence and utilization patterns for TTE and to provide clarification on potential omissions existing in the original 2007 criteria.
Previous studies assessed the appropriate use of TTE in different settings according to 2007 criteria, whereas two recent studies evaluated the 2011 AUC in a teaching hospital and in an outpatient setting. To date, the application of the new AUC and the resulting appropriateness rate of TTE for inpatients in a community setting have still not been evaluated.
This study was undertaken to explore the feasibility of application of the new AUC for echocardiography and the resulting prevalence of appropriate transthoracic echocardiographic examinations, in a consecutive series of inpatients referred for TTE in a community setting. In addition, a consecutive series of patients hospitalized in noncardiologic divisions who were not referred for TTE was also evaluated, to investigate the appropriateness rate of this clinical decision in this population.
Methods
Study Population
Five different hospitals participated in this multicenter, prospective, observational study: (1) Santa Maria Annunziata Hospital (Florence, Italy), (2) San Giovanni di Dio Hospital (Florence, Italy), (3) Santa Maria Nuova Hospital (Florence, Italy), (4) Mugello Hospital (Borgo San Lorenzo, Italy), and (5) Serristori Hospital (Figline Valdarno, Italy). All these facilities are community-based hospitals with no academic affiliations, providing care for 850,000 residents in the Florence area under the coordination of the Local Health Unit, representing the local agency of the public-based Italian National Health System. The first three centers are high-volume hospitals with full cardiac interventional capabilities, whereas the other two are low-volume peripheral hospitals with noninvasive cardiologic services. Although strict scientific relationships between these community facilities and the two local university hospitals exist (e.g., for the design and conduct of research studies or for the organization of scientific meetings), clinical practitioners at the participating centers have no direct teaching responsibilities. In the three principal hospitals, practitioners have direct access to cardiology consultants 24 hours a day. In the other two hospitals, direct access to cardiology consultants is available 12 hours a day, and a cardiologist is available by phone at night.
To evaluate the appropriateness of the clinical decision of referring patients for TTE, the study population (referral study group) was selected among all patients aged > 16 years hospitalized at these centers and consecutively referred for TTE over a 6-week enrollment period, between November and December 2010. To evaluate the appropriateness of the clinical decision of not referring patients for TTE, the medicine units of four participating hospitals (Santa Maria Annunziata, San Giovanni di Dio, Santa Maria Nuova, and Serristori) were involved. The study population for this analysis (nonreferral study group) was selected among all hospitalized patients aged > 16 years consecutively discharged from these units during the same 6-week enrollment period without being referred for TTE. Main patient characteristics at the time of echocardiographic examinations (for the referral study group) or at the time of hospital discharge (for the nonreferral study group) were prospectively recorded on a dedicated database.
Assessment of Appropriateness
Identification of Clinical Indication
The appropriateness of the indication for TTE for each patient was defined according to the 2011 AUC for echocardiography, which were published online in November 2010. In this document, which includes appropriateness criteria for TTE, transesophageal echocardiography, and stress echocardiography, a total of 98 indications for TTE are grouped in seven major classes. Some classes are divided into subclasses, encompassing the majority of clinical scenarios seen in daily practice. Each indication contained in the AUC corresponds to a score between 1 and 9. On the basis of this score, indications can be considered appropriate (score 7–9), of uncertain appropriateness (score 4–6), or inappropriate (score 1–3).
For the referral study group, assessment of the appropriateness was performed by a team of five investigators experienced in echocardiography who carefully reviewed patients’ electronic medical records according to the following procedure. The first step was the identification of the clinical indication for TTE. Evaluation was performed for each patient by taking into account past and recent clinical history, the timing and findings of previous echocardiographic studies and other instrumental or laboratory tests, the reason for the current hospitalization, potential changes in clinical status, and the primary reason for referral for TTE written in the note of the ordering physician. Once the clinical indication for TTE was identified, patients were classified by each investigator into one of the 98 indications for TTE listed in the AUC by choosing the one that best matched their clinical indications. Consensus was a priori defined as agreement among four or more raters in choosing the same indication listed in the AUC or in identifying patients’ clinical indications as unclassifiable, if the clinical indications did not match any scenario in the AUC. In case of disagreement, a second round of classification was obtained after discussion. If consensus was not achieved, patients’ clinical indications were also considered unclassifiable. This allowed the categorization of TTE as appropriate, of uncertain appropriateness, inappropriate, or unclassifiable. If assessment of the appropriateness was not possible because of inadequate or insufficient clinical documentation, patients were excluded from the analysis. For the whole period of observations, all clinicians working at the participating hospitals, with the exception of the investigators, were unaware of the ongoing appropriateness evaluation.
Assumptions
The appropriateness evaluation was carried out by taking into account the recommendations reported in the comments to the 2011 AUC. Attention was also given to some new general assumptions added to those of the 2007 criteria. Among these, particular importance was given to the following three issues: (1) the new definition of appropriateness given by the technical panel, highlighting the importance of implicitly considering cost and potential negative consequences in determining the appropriateness of a transthoracic echocardiographic examination (i.e., appropriateness is defined as “the condition in which the expected incremental information, combined with clinical judgment, exceeds the expected negative consequences by a sufficiently wide margin for a specific indication”); (2) the concept that appropriateness ratings reflect whether TTE is appropriate for a given patient, not whether TTE should be preferred over other diagnostic tests; and (3) the clarification that routine or surveillance TTE represents a periodic evaluation ordered after a certain period of time has elapsed and that is not driven by clinical factors. With regard to specific assumptions, particular importance was given to the new definitions of chest pain syndrome and ischemic equivalent and to the recommendation of classifying perioperative patients with symptoms or signs of cardiovascular disease under symptomatic indications (e.g., indication 1), not under indications in the perioperative category.
Referring Physician Specialty
Analyses were performed in the overall population and separately in the two groups referred for TTE by cardiologists and noncardiologists. For the assignment of patients to these two groups, in cases in which TTE referral was recommended to an internist or to another practitioner by a cardiology consultant, the patient was included in the group referred by cardiologists. TTE was considered recommended by a cardiology consultation if a clear and unambiguous indication for TTE was written by the consultant in the electronic medical record and if the date of request for TTE signed by the practitioner was not antecedent to that of the consultation.
Evaluation in the Nonreferral Group
Similar procedures were followed for the assessment of appropriateness in the nonreferral study group. The aim of this analysis was to identify possible areas in which the selection of patients candidates for TTE might be improved. Because no TTE requests were actually performed in this group, each patient was classified into one of the 98 indications for TTE listed in the AUC according to clinical history, the results of previous echocardiographic examinations and other diagnostic tests, the reason for current hospitalization, and potential changes in clinical status, choosing the one that best matched the patient’s clinical scenario. This allowed categorization of patients into groups of those for whom potential TTE referral would have been appropriate, of uncertain appropriateness, inappropriate, or unclassifiable. For this evaluation, the same assumptions used in the referral group were taken into account. In rating appropriateness in the nonreferral group, particular importance was also given to interpret the AUC by taking into account that they were not developed to evaluate patients who did not actually undergo TTE. Moreover, considering that the decision of not referring for TTE is sometimes related to other diagnostic information obtained during hospitalization (e.g., by other cardiac imaging examinations), an additional assumption was that appropriateness of potential TTE was defined at the time of discharge (i.e., by taking into account all clinical, laboratory, and instrumental findings available at discharge).
Assessment of Clinical Utility
For the purpose of this study, we defined the clinical utility of TTE as the reasonable evidence that the examination was associated with a definite change in clinical decision making. In particular, TTE was considered clinically useful if changes in clinical management—including any variation in diagnostic workup, therapeutic decisions, or follow-up planning—were entirely or partially driven by the results of TTE. For this evaluation, each member of the team was asked to give his or her opinion about the clinical management that theoretically would have occurred if TTE had not been performed and to compare it with the management that actually occurred.
Statistical Analysis
Data are expressed as mean ± SD. Categorical variables were compared using χ 2 tests or Fisher’s exact tests as appropriate. Age comparison between patients with and without inappropriate indications for TTE was performed using Student’s t test for independent samples. Interobserver reproducibility in the application of AUC was explored by analyzing the agreement between two independent experienced reviewers in a subset of 90 patients. Cohen’s κ was used as an index of agreement. All tests were two tailed. P values < .05 were considered significant. Analyses were performed using SPSS release 12.0 (SPSS, Inc., Chicago, IL).
Sample size calculations for this study were performed under the hypothesis that the comparison between the group of patients with inappropriate indications and that with appropriate or uncertain indications would have shown significant differences in the rate of clinically useful examinations using Fisher’s exact test. On the basis of data reported in a subset of inpatients included in a previous study of an Italian population, we assumed that 15% of patients in the referral study group would have been referred for TTE with inappropriate indications and that a 5% prevalence of clinically useful examination would have been found in this group. Even if this expected rate of inappropriate examinations was higher than that reported in US studies, we used this estimate obtained in an Italian inpatient population to minimize the risk for bias related to discrepancies in the appropriateness of TTE between the United States and Italy. Under these assumptions, a total sample size of 835 patients (125 with inappropriate indications and 710 with appropriate or uncertain indications) would have allowed us to detect an absolute difference of >10% in the proportion of clinically useful examinations, with 90% power and P < .05. Power analysis was performed using the inequality test for two independent proportions available in PASS version 11 (NCSS, LLC, Kaysville, UT).
Results
General Characteristics
During the period of enrollment, a total of 459 inpatients were referred for TTE by cardiologists, and 477 were referred by noncardiologists. Two patients in the former group and three in the latter group were excluded because of inadequate or insufficient clinical documentation. Overall, 931 subjects (mean age, 72.8 ± 14.4 years; 45.9% women) entered the referral study group. The group of patients referred by cardiologists included 33 patients (7.2%) for whom requests for TTE had been recommended by cardiology consultants to the ordering practitioners. Patients referred by cardiologists were more often male than those referred by noncardiologists (54.0% vs 37.4%, P < .0001), with no significant age difference (72.0 ± 14.0 vs 73.5 ± 14.8 years, respectively, P = .11).
The distribution of indications for TTE in the two groups according to major classes and subclasses of indications listed in the AUC is shown in Table 1 . Consensus in identifying the indication listed in the AUC that best matched patients’ clinical indications was achieved for all patients. In the group referred by cardiologists, nearly three quarters of all examinations were requested for a general evaluation of cardiac structure and function or for cardiovascular evaluation in an acute setting. In the group referred by noncardiologists, most examinations were requested for a general evaluation of cardiac structure and function or for evaluation of hypertension, heart failure, or cardiomyopathy. Considering the ordering physician’s specialty among patients referred by noncardiologists, the majority of examinations were requested by internists ( n = 348 [73.4%]). The remaining referring physicians included nephrologists ( n = 34 [13.5%]), oncologists ( n = 30 [6.3%]), anesthesiologists ( n = 24 [5.1%]), surgeons ( n = 19 [4.0%]), infectious disease specialists ( n = 6 [1.3%]), geriatrists ( n = 6 [1.3%]), orthopedists ( n = 4 [0.8%]), gynecologists ( n = 1 [0.2%]), rheumatologists ( n = 1 [0.2%]), and psychiatrists ( n = 1 [0.2%]).
| Indication | Cardiologists ( n = 457) | Noncardiologists ( n = 474) |
|---|---|---|
| TTE for general evaluation of cardiac structure and function | 176 (38.5%) | 172 (36.3%) |
| Suspected cardiac etiology (general) with TTE | 45 | 82 |
| Arrhythmias with TTE | 53 | 27 |
| Lightheadedness/presyncope/syncope with TTE | 27 | 24 |
| Evaluation of ventricular function with TTE | 41 | 29 |
| Perioperative evaluation with TTE | 7 | 9 |
| Pulmonary hypertension with TTE | 3 | 1 |
| TTE for cardiovascular evaluation in an acute setting | 162 (35.4%) | 70 (14.8%) |
| Hypotension or hemodynamic instability with TTE | 15 | 12 |
| Myocardial ischemia/infarction with TTE | 79 | 2 |
| Evaluation of ventricular function after ACS with TTE | 50 | 6 |
| Respiratory failure with TTE | 10 | 46 |
| Pulmonary embolism with TTE | 7 | 4 |
| Cardiac trauma with TTE | 1 | — |
| TTE for evaluation of valvular function | 33 (7.2%) | 37 (7.8%) |
| Murmur or click with TTE | 7 | 6 |
| Native valvular stenosis with TTE | 7 | 1 |
| Native valvular regurgitation with TTE | 15 | 8 |
| Prosthetic valves with TTE | 4 | 10 |
| Infective endocarditis (native or prosthetic valves) with TTE | 12 | 12 |
| TTE for evaluation of intracardiac and extracardiac structures and chambers | 6 (1.3%) | 10 (2.1%) |
| TTE for evaluation of aortic disease | 3 (0.7%) | 2 (0.4%) |
| TTE for evaluation of hypertension, HF, or cardiomyopathy | 65 (14.2%) | 179 (37.7%) |
| Hypertension with TTE | 10 | 62 |
| HF with TTE | 38 | 88 |
| Device evaluation (including pacemaker, ICD, or CRT) with TTE | 7 | 7 |
| Ventricular assist devices and cardiac transplantation with TTE | — | — |
| Cardiomyopathies with TTE | 10 | 22 |
| TTE for adult congenital heart disease | 3 (0.7%) | 2 (0.4%) |
| Unclassified | 9 (2.0%) | 2 (0.4%) |
Feasibility and Reproducibility
In the referral study group, application of the new AUC was feasible in 920 patients (98.8%). Eleven cases (nine among patients referred by cardiologists and two among those referred by noncardiologists) were considered unclassifiable because the clinical indication did not match any of the indications listed in the criteria. These unclassifiable clinical indications were reevaluation after elective percutaneous coronary revascularization with no acute coronary syndrome ( n = 7), reevaluation in asymptomatic patients with ventricular preexcitation after successful radiofrequency ablation ( n = 2), one case of asymptomatic sinus tachycardia with otherwise normal clinical examination, and case of recurrent acute chronic renal failure with no cardiovascular symptoms in a patient with a history of asymptomatic left ventricular dysfunction. Interrater variability results showed a good reproducibility of AUC (κ = 0.83; 95% confidence interval, 0.70–0.95).
Appropriateness of Indications for TTE
Among the 920 classifiable patients, indications for TTE were identified as appropriate in 739 (80.3%), of uncertain appropriateness in 46 (5.0%), and inappropriate in 135 (14.7%). Pooling the first two subsets, patients with inappropriate indications were younger than those with appropriate or uncertain indications (71.1 ± 15.2 vs 73.8 ± 13.4 years, P = .038), with no differences in gender distribution (46.5% vs 42.2% women, respectively, P = .36).
The appropriateness rate in the group referred by cardiologists (91.5% appropriate, 2.0% uncertain, 6.5% inappropriate) was higher in comparison with that referred by noncardiologists (69.7% appropriate, 7.8% uncertain, 22.5% inappropriate) ( P < .0001). The prevalence of different appropriateness levels in the two groups after stratification by major classes of indications is shown in Figures 1 and 2 . The highest prevalence rates of inappropriate indications were observed among patients referred for general evaluation of cardiac structure and function and among those referred for evaluation of hypertension, heart failure, or cardiomyopathy.
Most common appropriate, uncertain, and inappropriate specific indications are listed in Tables 2 and 3 . Of note, the most common inappropriate indications were all related to scenarios in which patients were referred for TTE despite no significant clinical findings. In particular, routine surveillance in patients with heart failure with no changes in clinical status (indication 74), routine evaluation of subjects with hypertension without symptoms or signs of hypertensive heart disease (indication 68), and routine perioperative evaluation of ventricular function with no symptoms or signs of cardiovascular disease (indication 13) accounted for 23.7%, 15.6%, and 11.1% of all inappropriate examinations in the study population, respectively. Major causes of hospitalization among patients with inappropriate indications for TTE were abnormalities in laboratory or instrumental noncardiac examinations (e.g., anemia, hyperglycemia, pulmonary disease at routine chest x-ray, abnormal findings at abdominal ultrasound) in asymptomatic patients with known cardiovascular disease (e.g., ischemic heart disease, chronic heart failure, hypertension) and no change in clinical status or need for noncardiac elective surgery in patients with no symptoms or signs of cardiovascular disease.
| Indication | n (%) |
|---|---|
| Most common appropriate indications | |
| Class: TTE for cardiovascular evaluation in an acute setting | 79 (17.6) |
| Subclass: myocardial ischemia/infarction with TTE | |
| Indication 21: acute chest pain with suspected MI and nondiagnostic ECG findings when a resting echocardiogram can be performed during pain (appropriate use score 9) | |
| Class: TTE for general evaluation of cardiac structure and function | 52 (11.6) |
| Subclass: arrhythmias with TTE | |
| Indication 5: sustained or nonsustained atrial fibrillation, SVT, or VT (appropriate use score 9) | |
| Class: TTE for cardiovascular evaluation in an acute setting | 50 (11.2) |
| Subclass: evaluation of ventricular function after ACS with TTE | |
| Indication 24: Initial evaluation of ventricular function following ACS (appropriate use score 9) | |
| Most common uncertain indications | |
| Class: TTE for evaluation of hypertension, HF, or cardiomyopathy | 4 (0.9) |
| Subclass: HF with TTE | |
| Indication 72: reevaluation of known HF (systolic or diastolic) with a change in clinical status or cardiac exam with a clear precipitating change in medication or diet (appropriate use score 4) | |
| Class: TTE for evaluation of valvular function | 2 (0.4) |
| Subclass: native valvular regurgitation with TTE | |
| Indication 45: routine surveillance (<1 y) of moderate or severe valvular regurgitation without a change in clinical status or cardiac exam (appropriate use score 6) | |
| Class: TTE for cardiovascular evaluation in an acute setting | 2 (0.4) |
| Subclass: respiratory failure with TTE | |
| Indication 27: respiratory failure or hypoxemia when a noncardiac etiology of respiratory failure has been established (appropriate use score 5) | |
| Most common inappropriate indications | |
| Class: TTE for general evaluation of cardiac structure and function | 9 (2.0) |
| Subclass: evaluation of ventricular function with TTE | |
| Indication 11: routine surveillance of ventricular function with known CAD and no change in clinical status or cardiac exam (appropriate use score 3) | |
| Class: TTE for general evaluation of cardiac structure and function | 7 (1.6) |
| Subclass: perioperative evaluation with TTE | |
| Indication 13: routine perioperative evaluation of ventricular function with no symptoms or signs of cardiovascular disease (appropriate use score 2) | |
| Class: TTE for evaluation of hypertension, HF, or cardiomyopathy | 4 (0.9) |
| Subclass: HF with TTE | |
| Indication 74: routine surveillance (<1 y) of HF (systolic or diastolic) when there is no change in clinical status or cardiac exam (appropriate use score 2) | |
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