Handheld ultrasound to reduce requests for inappropriate echocardiogram (HURRIE).

BACKGROUND: Handheld ultrasound could provide sufficient information to satisfy the clinical questions underlying 'rarely appropriate' echo requests, but there are limited data about its use as a gatekeeper to standard echocardiography. We sought to determine whether the use of handheld ultrasound could improve the appropriate use of echocardiography.
METHOD: A prospective study comparing handheld ultrasound strategy to standard echocardiography for studies deemed rarely appropriate, using a questionnaire based on appropriate use criteria was conducted across two hospitals, from October 2017 to April 2018.
RESULTS: Groups undergoing Handheld ultrasound (n = 76, 58 (46.5-72.5) years, 53 males, 78% outpatients) and standard echocardiography (n = 72, 61 (49.0-71.5) years, 42 males, 76% outpatients) were comparable. There was a significant decrease in the time to scan from just over 1 month in standard group to a median of 12 days in handheld ultrasound group (P < 0.001). This difference was small for inpatients (from 1 day to a median of 10 min in handheld ultrasound, P = 0.014), but prominent in outpatients (from 1.5 months in the standard group to median of 2 weeks in the handheld ultrasound group, P < 0.001). There was no increase in the need for follow-up scan within 6 months and no significant differences in length of hospital stay for inpatients.
CONCLUSION: Handheld ultrasound can be an effective gatekeeper to standard echocardiography for requests deemed rarely appropriate, reducing time to echocardiography significantly and potentially decreasing the need for standard echocardiography by up to 20%.

Introduction

The use of cardiovascular imaging continues to grow. In Australia, there is a 17-fold geographic variation in age-standardised imaging use, attributable more to ease of access and numbers of ordering physicians than it is to the prevalence of cardiovascular disease (1, 2, 3). Appropriate echocardiograms are those that are likely to contribute to improving patients’ clinical outcomes, and importantly, inappropriate use of echocardiography may potentially generate unwarranted costs to the healthcare system (4). Although in North America, the Appropriate Use Criteria (AUC) have been adopted to define when a test should be ordered (5), there are several limitations to the use of an AUC process to control utilisation (6). Moreover, it is not clear that adoption of the AUC reduces utilisation.

There may be a technological solution to the problem of rarely appropriate (RA) echocardiograms. A simple screening algorithm can be used to identify inappropriate requests (7), and in these patients, a full 45–60-min echocardiogram can be circumvented by performance of a limited echocardiogram using handheld ultrasound (HHU). A previous report suggested that HHU could be used to reduce the time to echocardiography and cost compared to retrospective controls (8). We designed a prospective audit to address whether HHU could be applied as a gatekeeper to standard transthoracic echocardiography (StTTE) for rarely appropriate examinations, reducing numbers of StTTE performed and identifying important pathology that would have been missed if RA tests were cancelled.

Methods

Study design

In 2017, a policy of screening for appropriate use was introduced for all echocardiogram requests in patients above the age of 16 years referred for echocardiography in the Sunshine and Footscray Hospital campuses of Western Health (Melbourne, Australia). After they were evaluated for appropriateness, requests were assigned to either a handheld device pathway or the standard echocardiography pathway. The pathway was determined by availability of appropriate resources for example appropriately trained operator or the appropriate outpatient list, available on 3 days of the week (Fig. 1). In this prospective audit, performed from October 2017 to April 2018, we also collected patient demographics and followed patients after 6 months. The protocol was approved by the Human Research Ethics Committee of Western Health.

Figure 1

Study design.

Identification of RA echocardiograms

Patients were considered likely to have a RA echocardiogram if two of the four questions on a simplified questionnaire (9) (Appendix 1) were positive. The rationale of this is that it is too complex to incorporate >100 categories of AUC into day-to-day practice. The use of this simplified questionnaire identifies >80% of RA tests (9).

Echocardiography

Standard echocardiograms were performed using a standard protocol (10) using commercially available machines (Vivid e9, GE Medical Systems; Acuson SC2000, Siemens; EPIC 5, Philips Medical Systems).

The HHU examination was performed with an App-based ultrasound transducer with a compatible Android smart device (Lumify S4-1, Philips Medical Systems). The HHU study protocol involved only 2D and colour Doppler images across all standard echocardiographic views (Table 1). Spectral Doppler data were not part of the assessment as this feature is not available on the HHU. Disease severity was approximated from structural clues for stenotic lesions, and the size and duration of the colour jet (10). Linear or area measurements were made as appropriate.

Table 1

HHU protocol.

Parasternal long axis

2D images

Colour flow Doppler of valves

RV inflow view

2D images and colour

Parasternal short axis

Short-axis view at the aortic level and RVOT

Colour flow to evaluate pulmonic, aortic and tricuspid valve

Left ventricle at mitral valve (MV) level

Left ventricle at mid-level

Left ventricle at apex

Apical four chamber

2D imaging of the four chambers

Colour flow Doppler of valvular inflow and regurgitation

Colour flow of the interatrial septum

Apical five chambers

2D imaging

Colour flow Doppler of LVOT

Apical two chamber

2D imaging

Colour flow Doppler of MV

Apical long axis

2D imaging

Colour flow Doppler to visualise aortic and mitral forward and regurgitant flow

Subcostal view

Four chambers

2D imaging

Colour flow Doppler of at interatrial septum to assess for shunt

Inferior vena cava assessment

IVC images to evaluate size and dynamics

Suprasternal notch

Long axis view of the aortic arch

Other views as indicated for further clarification of assessment of specific pathologies

All HHUs were performed by a sonographer specialised in echocardiography, cardiology trainee or cardiologist depending on availability. Images were wirelessly uploaded to the local echo database for reporting. All studies were reported by the cardiologist allocated for reporting studies for the day. A full study was requested if the HHU (1) was non-diagnostic, (2) identified a new abnormality or a change in a previously known abnormality.

Follow-up

Patients were followed up after 6 months to identify the need for repeat echocardiograms and other predefined outcomes.

Statistical analysis

Baseline characteristics and outcomes were compared for the HHU and StTTE groups. Continuous variables were compared using rank-sum test, while Fisher’s exact test was used for categorical variables with a P < 0.05 considered statistically significant.

Results

Baseline characteristics

From 1877 echocardiography requests screened using the four appropriateness questions, 166 requests (8.8%) were deemed RA. These 166 were assigned either to HHU or StTTE, and studies were performed according to the availability of a suitably qualified person to perform the HHU and standard echocardiogram. After exclusion of 18 patients, who were unable to attend for echocardiography appointment, 148 patients (76 HHU and 72 StTTE) in whom RA tests had been requested were included. There were no significant differences in the clinical or the request characteristics of the two groups (Table 2). A cardiologist was the requesting physician in 43% of the HHU and 40% of StTTE examinations. The remaining requests in each arm were ordered by a combination of medical and surgical doctors. Routine cardiac follow-up in the absence of cardiovascular signs and symptoms was the most common reason for tests being labelled RA (Table 2).

Table 2

Baseline characteristics.

	HHU	StTTE	P
n	76	72
Age (years), median (IQR)	58 (46.5–72.5)	61 (49.0–71.5)	0.38
Sex
Female	23 (30%)	29 (40%)	0.18
Specialty
Non-cardiology	43 (57%)	43 (60%)	0.70
Setting
Outpatient	59 (78%)	55 (76%)	0.86
HTN	33 (43%)	30 (42%)	0.83
DM	22 (29%)	16 (22%)	0.35
Valvular disease	8 (11%)	6 (8%)	0.78
AF	10 (13%)	6 (8%)	0.43
IHD	19 (25%)	20 (28%)	0.70
Heart failure (systolic or diastolic)	30 (39%)	29 (40%)	1.00
Lung disease	10 (13%)	12 (17%)	0.65
Renal disease	20 (26%)	17 (24%)	0.85
Liver disease	3 (4%)	1 (1%)	0.62
Endocarditis study	7 (9%)	7 (10%)	1.00
No change in signs or symptoms	72 (95%)	70 (97%)	0.68
Routine	68 (89%)	64 (89%)	1.00
Echo in last year	28 (37%)	33 (46%)	0.27
Reason for inappropriateness
Absence of new CV signs and symptoms + routine	40 (53%)	32 (44%)	0.32
Absence of new symptoms + routine + previous TTE	25 (33%)	30 (42%)	0.27
Suspected endocarditis + absence of new symptoms	5 (7%)	7 (10%)	0.56
Other combinations	6 (8%)	3 (4%)	0.50

Outcomes

There was a significant decrease in the time to scan from just over 1 month in standard group to a median of 12 days in HHU group (P < 0.001). This difference was small for inpatients (from 1 day to a median of 10 min in HHU, P = 0.014), but prominent in outpatients (from 1.5 months in the standard group to median of 2 weeks in the HHU group, P < 0.001) (Fig. 2).

Figure 2

Time to scan.

Other outcomes are shown in Table 3. There was no statistical difference in finding new observations or in physician satisfaction between the HHU and stTTE group. There was no increase in a need for follow-up within 6 months, with around 15% of each group requiring a follow-up. Length of stay for inpatients was not significantly different between the groups.

Table 3

Outcomes.

	HHU (n = 76)	StTTE (n = 72)	P value
Time to scan (days) – overall, median (IQR)	12.0 (4.0, 19.1)	36.03 (3.93, 70.46)	<0.001
Time to scan (days) – Inpatient, median (IQR)	0.17 (0.08, 0.79) (n = 17)	0.92 (0.25, 1.00) (n = 17)	0.01
Time to scan (days) – Outpatient, median (IQR)	14.00 (8.00, 22.00) (n = 59)	46.78 (21.77, 76.84) (n = 55)	<0.001
Length of stay (days) – Inpatient, median (IQR)	13.0 (4,71, 17.63) (n = 17)	10.12 (6.63, 12.95) (n = 17)	0.8
New observation/or change in management	10 (13%)	8 (11%)	0.7
Physician satisfaction (1–5) 1 is least satisfied and 5 is most satisfied – inpatient (n = 17)			0.8
3 4 5	1 (6%)3 (18%)13 (76%)	0 (0%)2 (12%)15 (88%)
Need for follow-up echocardiography	11 (14%)	11 (15%)	1.00

Discussion

The results of this study show that HHU can be used as a tool to reduce RA echocardiograms by significantly decreasing time to scan in both inpatient and outpatient settings without decreasing physician satisfaction or increasing the need in follow-up stTTE within 6 months. To our knowledge, this is the first prospective study to use HHU to reduce RA echocardiograms.

Handheld ultrasound

Echocardiography has been a major beneficiary of Moore’s law (11) of increased processing power and memory with miniaturisation and falling cost. This is well exemplified by the most recent generation of handheld ultrasound (HHU) systems, which provide image quality analogous to a full-sized machine and are able to perform wireless transfer of images to a picture-archiving and communication system. Morphological, valvular and functional assessment of cardiac chambers by HHU has been shown to be analogous with stTTE (12, 13).

Apart from reliability, an HHU-based approach towards AUC also reduces cost and waiting time to scan. A previous cost analysis showed that a HHU-based approach would save up to $72 USD per study (8). Decreasing costs have also been replicated for using HHU in other clinical settings by other groups (8, 14). Our study shows that a HHU-based approach can decrease time to scan in both inpatient and outpatient settings. Although the inpatient time to scan decrease was modest, the change in outpatient time to scan was significant (median time to scan 14 days with HHU vs 46 days for stTTE (Fig. 2)). This reduction in time to scan is not at the expense of repeating the stTTE after performing a HHU protocol, as there was no increase in the follow-up stTTE in 6 months.

Appropriate use

RA echocardiograms comprise 10–20% of echocardiogram requests (6, 15). While the exclusion of these studies has been considered as a means of improving efficiency, the reality is more complicated. First, clinicians arrange echocardiograms because of diagnostic uncertainty (16), and application of AUC to restrict test ordering is difficult to fit to the nuances of clinical presentation. Second, RA echocardiograms not uncommonly identify new and significant findings. Third, AUC are less firmly based on evidence than are the guidelines, and in some places contradict the guidelines (7). Indeed, there is not much evidence that AUC has engendered improvements in rates of inappropriate use (6).

As imaging continues to grow, the burden of the RA echocardiograms will increase and addressing the issue will become more urgent. The use of point-of-order radiology benefits management software based on the AUC have been proposed, but limits access to echocardiography in situations when it may be of clinical value (5, 17). The efficacy of education for reducing RA studies has been variable, and even if effective, is of uncertain durability.

The use of HHU as a replacement for a full echocardiogram seems to provide sufficient information to satisfy the referring physician, and follow-up echocardiography is not commonly required (14). The results of our study show that the use of HHU for RA studies decreases waiting times, while creating a safety net in picking up abnormalities which could have been missed if the test was cancelled. The new observations that required a change in management occurred in 13% of HHU and 11% of stTTE. These results are concordant with the previous literature regarding new observations and abnormalities leading to change in management in RA studies (18, 19).

Limitations

The decision to undertake HHU in place of StTTE (when HHU resources were available) became a laboratory policy which this study sought to audit, so randomisation was not possible. Nonetheless, the groups were closely comparable. The average waiting time to scan might vary from one centre to another, so the external validity of these findings may vary.

Conclusion

Although echocardiography is a mature imaging modality, the development of new technologies continues to transform its clinical application. In this prospective comparison in of HHU to stTTE, HHU was a safe and reliable method for dealing with RA echocardiogram requests with less cost and shorter waiting times than laboratory echocardiograms.

Declaration of interest

The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.

Funding

Supported in part by a Partnership grant from the National Health and Medical Research Council, Canberra, Australia. T H M is in receipt of research support from General Electric Medical Systems for an ongoing research study on the use of strain for the assessment of cardiotoxicity. No external funding was obtained for the study, which was performed with handheld systems loaned by Philips Medical Systems, Andover, MA.