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A decision aid for referring patients with systolic murmurs for echocardiography
J C Fink1, C H Schmid, H P Selker
1Division of Clinical Care Research, New England Medical Center, Boston, Massachusetts 02111.
Insights
Primary care providers can reduce unnecessary echocardiograms in healthy patients with systolic murmurs. Focusing on younger, female patients with lower-grade murmurs can avoid nearly half of these cardiac tests.
Area of Science:
- Cardiology
- Primary Care Medicine
- Diagnostic Imaging
Background:
- Echocardiography is frequently ordered for healthy patients with systolic murmurs.
- Predictors for significant cardiac lesions in this population are not well-defined.
Purpose of the Study:
- To describe echocardiography ordering patterns in primary care for healthy patients.
- To develop a decision aid for identifying patients with systolic murmurs who have significant cardiac lesions.
Main Methods:
- Retrospective case review of 169 patients (18-55 years) undergoing echocardiography.
- Logistic regression analysis to identify predictors of positive echocardiographic outcomes.
- Development of a predictive model and receiver-operating characteristic (ROC) curve analysis.
Main Results:
- Symptoms and auscultatory findings were not predictive of positive echocardiographic outcomes.
- Significant predictors for positive echocardiograms in patients with systolic murmurs included older age, male gender, and murmur grade ≥3.
- A model incorporating these factors achieved an ROC curve area of 0.741.
Conclusions:
- Healthy patients, particularly young females with lower-grade systolic murmurs (grade ≤2), are unlikely to have significant cardiac lesions.
- Implementing stricter screening criteria for this low-risk group could reduce unnecessary echocardiograms by approximately 47% while maintaining high sensitivity (90%).
Objective:
To describe the practice pattern of a group of primary care providers in ordering echocardiography for healthy patients and to derive a decision aid to identify patients with systolic murmurs who have significant cardiac lesions.
Design:
Retrospective case review of clinical variables, including the demographic, historical, and physical examination features obtained from chart review of the physician evaluation prior to referral for echocardiography and the echocardiographic results, with both univariate and multivariate regression analyses used to identify variables predictive of positive echocardiographic outcomes and to derive a regression model.
Setting:
General internal medicine clinic in an urban major teaching hospital.
Patients/Participants:
169 patients between the ages of 18 and 55 years selected retrospectively from medical records.
Measurements And Main Results:
Symptoms and auscultatory findings were not predictive of positive echocardiographic outcomes among the patients referred for the test. For the patients who had systolic murmurs, a logistic regression model had three significant predictors of positive echocardiographic results: additional year of age (odds ratio: 1.08, 95% CI: 1.02-1.13; p = 0.007); male gender (odds ratio: 5.87, 95% CI: 1.99-17.3; p = 0.002); and murmur grade > or = 3 (odds ratio: 4.99, 95% CI: 1.27-19.6; p = 0.02). The receiver-operating characteristic (ROC) curve area for this model was 0.741. If women aged 35 years and less with murmur grades < or = 2 had not been referred, 47% of the echocardiographies could have been avoided while retaining a sensitivity of 90%.
Conclusions:
The study suggested that healthy patients with systolic murmurs are least likely to have positive echocardiographic results when they are young and female and have murmur grades < or = 2. More careful screening of this group might make unnecessary almost half of the echocardiographies yielding negative results ordered for healthy patients with systolic murmurs.