The clinical impact of echocardiography on antibiotic prophylaxis use in patients with suspected mitral valve prolapse

Repeated echocardiographic examinations of patients with suspected infective endocarditis

OBJECTIVE

To study the diagnostic contribution of repeated transthoracic (TTE) and transoesophageal echocardiography (TOE) among patients with suspected infective endocarditis.

METHODS

262 patients with 266 episodes of suspected infective endocarditis were referred for TTE and TOE over three years in a 423 bed university cardiology hospital. Patients were a mean (SD) of 47.6 (17.9) years old. 139 (52.3%) episodes occurred in men and 127 (47.7%) in women. The diagnostic information obtained from repeated TTE and TOE examinations was evaluated relative to the diagnosis of endocarditis.

RESULTS

TTE examinations were repeated in 192 (72.2%) and TOE examinations were repeated in 49 (18.4%) of 266 episodes. A mean of 2.4 TTE and 1.2 TOE examinations were performed for each episode of suspected endocarditis. The second and third TTEs added diagnostic information in 34 (26.7%) and the second and third TOEs added diagnostic information in 25 (19.7%) of 127 episodes with definite endocarditis. After the third TTE or TOE no additional diagnostic information was obtained.

CONCLUSIONS

The diagnostic contribution of repeated TTE or TOE for the diagnosis of endocarditis decreased as the number of repetitions increased. In this setting, the data do not substantiate more than three TTE or TOE examinations as an efficient strategy to increase the diagnostic yield for all but selected patients with suspected endocarditis.

Usefulness of a hand-carried cardiac ultrasound device to detect clinically significant valvular regurgitation in hospitalized patients

The accuracy of a hand-carried cardiac ultrasound (HCCU) device for the diagnosis of valvular regurgitations using color-flow Doppler was assessed. One hundred twenty hospitalized patients with at least mild valvular regurgitation by standard echocardiography were evaluated by 2 cardiologists using HCCU. The HCCU operator identified 99% of clinically significant valvular regurgitations and assessed the severity correctly in 83% of cases. For mild regurgitation, the HCCU sensitivity and specificity were 82% and 93%, respectively, resulting in correct assessments of severity in 71% of cases. HCCU used by trained cardiologists has high sensitivity for the detection and accurate assessment of the severity of clinically relevant valvular regurgitation.

Impact of a specific echocardiographic report comment regarding endocarditis prophylaxis on compliance with American Heart Association recommendations

BACKGROUND

There is substantial underuse and overuse of antibiotic prophylaxis. Current American Heart Association (AHA) recommendations are heavily dependent on echocardiographic data that may not be familiar to referring physicians. We sought to determine the impact of a specific prophylaxis report comment on compliance with AHA recommendations.

METHODS AND RESULTS

Using a standardized electronic reporting system, physicians interpreting approximately 50% of echocardiograms included a concluding comment classifying endocarditis risk and stating whether prophylaxis was indicated. The remaining reports were identical in format/content but did not include such comments. Of 1461 eligible outpatients during a 6-month period, 969 (66.3%) responded to a mail survey regarding prophylaxis instructions. Overall, 50% reported taking prophylaxes. Compliance with AHA recommendations was greater among those with a comment (73.2% versus 65.4% for those receiving versus those not receiving comments, respectively; P=0.011), with particular improvement among moderate-risk patients (69.5% versus 59.9%, P=0.024).

CONCLUSIONS

An echocardiographic report statement regarding endocarditis risk and need for prophylaxis is a simple low-cost intervention that improves compliance with AHA recommendations. Interpreting physicians should become familiar with AHA recommendations and include a concluding statement addressing prophylaxis.

Limited cardiac ultrasound examination for cost-effective echocardiographic referral

BACKGROUND

Although a standard echocardiogram is frequently requested and requires significant resources, few data exist on methods to improve referral for this examination. Therefore, we sought to determine the diagnostic value of a limited echocardiographic examination and to predict the cost-effectiveness of a limited imaging strategy on echocardiographic referral.

METHODS

A limited echocardiographic examination was reviewed for abnormalities and compared with standard echocardiographic findings. Assuming an imaging strategy in which a normal limited echocardiographic examination would negate the need for standard echocardiography, we calculated the diagnostic yields, the number of full echocardiographic studies eliminated, and the number of abnormal cases missed. We also stratified data by patient age (< or > or = 65 years), inpatient versus outpatient status, gender, referral diagnosis, and referring physician subspecialty.

RESULTS

In 151 outpatients, overall diagnostic yield was 47% (95% CI [39%, 55%]), and was lower in those younger than 65 years, in women, and in noncardiologist referral. In 155 inpatients, yields were 75% (95% CI [67%, 83%]) and were also related to age, but not to gender, diagnosis, and physician subspecialty. Sensitivity, specificity, negative and positive predictive values, and accuracy for the limited echocardiographic examination was 77%, 72%, 67%, 81%, and 75%, respectively. The limited imaging strategy negated 70% of studies in the outpatient group younger than 65 years, with a less than 5% chance of missing a clinically significant finding.

CONCLUSION

A limited echocardiographic imaging strategy is most cost-effective when used in young outpatients, where it can result in a substantial reduction in referral for standard echocardiography while rarely missing findings.