Cost-effectiveness of echocardiography for evaluation of children with murmurs

The discerning ear: cardiac auscultation in the era of artificial intelligence and telemedicine

Heart murmur, a thoracic auscultatory finding of cardiovascular origin, is extremely common in childhood and can appear at any age from premature newborn to late adolescence. The objective of this review is to provide a modern examination and update of cardiac murmur auscultation in this new era of artificial intelligence (AI) and telemedicine. First, we provide a comprehensive review of the causes and differential diagnosis, clinical features, evaluation, and long-term management of paediatric heart murmurs. Next, we provide a brief history of computer-assisted auscultation and murmur analysis, along with insight into the engineering design of the digital stethoscope. We conclude with a discussion of the paradigm shifting impact of deep learning on murmur analysis, AI-assisted auscultation, and the implications of these technologies on telemedicine in paediatric cardiology. It is our hope that this article provides an updated perspective on the impact of AI on cardiac auscultation for the modern paediatric cardiologist.

Managing a "New" Murmur in Healthy Children and Teens

An asymptomatic child with a murmur can be challenging practice management conundrum. Some providers refer all patients with a "new" murmur to a cardiologist, likely resulting in excessive resource utilization and parental anxiety. This study examines whether the prevalence of significant cardiac pathology differs in asymptomatic patients aged 2 to 18 years who were referred for a murmur that was "new" versus those referred for a murmur that was known to exist and followed conservatively during the previous 2 years. Of 473 patients meeting inclusion criteria, 33/473 (7.0%) were diagnosed with cardiac pathology, with 21/357 (5.9%) occurring among "new" murmur referrals and 12/116 (10.3%) occurring among "known" murmur referrals. Notably, 34/357 (9.5%) patients referred for a "new" murmur had no murmur present when assessed by the cardiologist. This study suggests that asymptomatic children with a "new" murmur may be conservatively managed. This may lessen health care resource utilization rates and overall parental anxiety.

Cardiovascular biomarkers pro-atrial natriuretic peptide and pro-endothelin-1 to monitor ductus arteriosus evolution in very preterm infants

BACKGROUND

The diagnostic and prognostic appraisal of patent ductus arteriosus (PDA) in preterm infants is still debatable.

AIMS

To compare plasma cardiovascular biomarkers with echocardiographic indices alongside ductus arteriosus (DA) evolution in very preterm infants within the first week of life.

METHODS

Mid-regional pro-atrial natriuretic peptide (MR-proANP) and C-terminal pro-endothelin-1 (CT-proET-1) levels were prospectively measured on the second and sixth days of life (DOL) in 52 preterm infants born before 32weeks of gestation. Echocardiographic indices to define DA patency and significance were simultaneously obtained. Logistic regression and receiver operating characteristics (ROC) analyses were used to assess and quantify the biomarkers' diagnostic capacities.

RESULTS

Thirty infants exhibited PDA on DOL 2; in 21 of these infants, DA was characterized as hemodynamically significant. Treatment failure after a first course of indomethacin was noted in 8 infants (DOL 6), whereas 7 participants underwent later surgical ligation. The diagnostic accuracy of cardiovascular biomarkers was moderate on DOL 2 but high on DOL 6. PDA was the only significant predictor of MR-proANP levels on DOL 6, independent of the effect of clinical confounders (regression coefficient 0.426, R(2) 0.60). Infants with MR-proANP ≥850pmol/l on DOL 2 had 3.9-fold higher risk (95% CI 1.01 to 14.5) of being diagnosed with significant DA, whereas infants with MR-proANP ≥700pmol/l on DOL 6 had 7.1-fold higher risk (1.9 to 27.2) for pharmaceutical treatment failure.

CONCLUSION

The cardiovascular plasma biomarker MR-proANP is a promising candidate for monitoring PDA evolution in very preterm infants.

The prevalence of valvular abnormalities in patients who were referred for echocardiographic examination with a primary diagnosis of "heart murmur"

INTRODUCTION

The prevalence of valvular abnormality and innocent murmur in patients who are referred for echocardiographic evaluation with the diagnosis of "murmur" is not known. The goal of this study was to evaluate the prevalence of valvular abnormalities in such patients.

METHODS

We retrospectively reviewed the echocardiograms that were referred with the primary ordering diagnosis of "murmur," for the presence of valvular abnormalities. For comparison, we used other documented primary reasons for echocardiographic referral, such as chest pain, shortness of breath, etc.

RESULTS

In this cohort, 7,684 echocardiogram reports documented primary diagnostic reasons for echocardiographic referral. A total of 3,460 echocardiogram reports (45%) were coded "murmur" as the primary reason for the study referral. There was a higher prevalence of female patient referrals for heart murmur evaluation (61.8% vs. 38.2%). Although, patients with murmur had a higher prevalence of valvular abnormalities, compared to other reasons for echocardiographic examination, the prevalence of valvular abnormality was less than 50% (48.6% vs. 35.5%) in both groups. Despite the higher number of female patients referred with the diagnosis of murmur, the percentage of abnormal valves was lower in women (45.6% vs. 53.4% in men).

CONCLUSION

The prevalence of valvular abnormalities in patients who were referred with the diagnosis of murmur for echocardiographic examination was less than 50%, with a lesser degree found in women. Routine utilization of echocardiography for evaluation of all murmurs may be unwarranted.

The contribution of pulse oximetry to the early detection of congenital heart disease in newborns

Approximately half of all newborns with congenital heart disease are asymptomatic in the first few days of life. Early detection of ductal-dependant cardiac malformations prior to ductal closure is, however, of significant clinical importance, as the treatment outcome is related to the time of diagnosis. Pulse oximetry has been proposed for early detection of congenital heart disease. The aims of the present study were: 1) to determine the effectiveness of a pulse-oximetric screening performed on the first day of life for the detection of congenital heart disease in otherwise healthy newborns and 2) to determine if a pulse-oximetric screening combined with clinical examination is superior in the diagnosis of congenital heart disease to clinical examination alone. This is a prospective, multi-centre study. Postductal pulse oximetry was performed between six and twelve hours of age in all newborns of greater than 35 weeks gestation. If pulse-oximetry-measured arterial oxygen saturation was less than 95%, echocardiography was performed. Pulse oximetry was performed in 3,262 newborns. Twenty-four infants (0.7%) had repeated saturations of less than 95%. Of these infants, 17 had congenital heart disease and five of the remaining seven had persistent pulmonary hypertension. No infant with a ductal-dependant or cyanotic congenital heart disease exhibited saturation values greater or equal to 95%.

CONCLUSION

postductal pulse-oximetric screening in the first few days of life is an effective means for detecting cyanotic congenital heart disease in otherwise healthy newborns.

The paediatrician and cardiac auscultation

The cardiac auscultation (CA) skills of paediatric residents and office-based paediatricians have recently been shown to be suboptimal. CA is known to have a high degree of specificity and sensitivity, and is inexpensive. New teaching aids and availability of surrogate patient heart sounds and murmurs now allow most physicians to acquire CA skills. These teaching aids should be available in all medical schools and in all postgraduate paediatric training programs. While the relationship between musicality and CA skill has not been proven, the author assumes this relationship to be valid. Specific learning objectives in CA should be established. Recognizing that the current trend is away from clinical examinations, students frequently are unaware that a CA learning deficit exists. Therefore, students' CA skills should be evaluated before medical school graduation and at the Royal College of Physicians and Surgeons specialty examination. Students with amusia (inability to distinguish pitch of sound) should be identified and consideration should be given to directing them away from a clinical specialty in which CA is important. Further study is required in the physiology of learning of CA. Appropriate action by medical school and paediatric postgraduate program directors and the Royal College will effect a higher standard of patient care by increasing CA skills, resulting in a more financially efficient system - something everyone is trying to achieve in these times of increasing medical care costs.

Evaluation of heart murmurs in children: cost-effectiveness and practical implications

OBJECTIVE

To assess the cost-effectiveness of various strategies to evaluate heart murmurs in children.

METHODS

We modeled 6 strategies to follow the initial examination by the pediatrician: (1) refer suspected pathologic murmurs to a cardiologist, (2) obtain a chest radiograph (CXR) and electrocardiogram (ECG) and refer suspected pathologic murmurs to a cardiologist, (3) refer suspected pathologic murmurs for an echocardiogram (ECHO), (4) obtain a CXR and ECG and refer suspected pathologic murmurs for an ECHO, (5) refer all patients with murmurs to a cardiologist, or (6) refer all patients with murmurs for an ECHO.

RESULTS

The least effective was strategy 1, which detects 82% of pathologic murmurs at $72 per patient evaluated. Strategy 5 detects 95% of pathologic murmurs at $38,000 per additional case detected over strategy 1. The most effective, strategy 6, detects 100% of pathologic murmurs at $158,000 per additional case detected over strategy 5. Strategies 2, 3, and 4 were not cost-effective. The results were sensitive to the costs of cardiology referral and ECHO.

CONCLUSIONS

Adding a CXR and ECG to the pediatrician's evaluation, or selectively referring directly to ECHO increases costs with little gain in accuracy. Given the current cost constraints present in health care, whether the optimal strategy involves referring to a cardiologist or obtaining an ECHO for all patients with murmurs depends on how much society should allocate to diagnose pathologic murmurs.

Diagnostic accuracy of pediatric echocardiograms performed in adult laboratories

Although cardiologists who treat adults have been evaluating pediatric patients using echocardiography since the early 1980s, the diagnostic accuracy of such studies has never been tested. To prospectively assess diagnostic accuracy of pediatric echocardiograms performed in adult laboratories (adult-lab echos) compared with evaluations of the same patients in pediatric laboratories (pediatric-lab echos), we gathered data from 66 patients, ages 1 day to 18 years (median 19 months), who underwent adult-lab echos in community hospitals or private offices before evaluation by a pediatric cardiologist; subsequently, 65 underwent pediatric-lab echos in a university hospital laboratory. Echocardiographic diagnoses were compared with (1) diagnoses proved by catheterization or surgery (25 patients), and (2) echocardiographic diagnoses verified by blinded duplicate-observer review (41 patients). Eighteen patients had no cardiac disease; 42 had simple lesions, 5 had intermediate lesions, and 1 had a complex lesion. In 25 patients with 46 procedure-proven diagnoses, the most important error per adult-lab echo was major in 11 (44%), moderate in 7 (28%), and minor in 3 (12%); in pediatric-lab echos it was major in 0 (0%), moderate in 1 (4%), and minor in 1 (4%). In 41 patients with 62 duplicate-observer-verified diagnoses, the most important error per adult-lab echo was major in 5 (12%), moderate in 12 (29%), and minor in 5 (12%); pediatric-lab echos had no errors. In 35 of 66 adult-lab echos (53%), the most important error was major or moderate. Of these, 71% were interpretive, 17% technical, and 11% both. Error incidences were not related to patient age, study year, use of color Doppler, or complexity of diagnoses. In 29 of these 35 patients, pediatric-lab echos resulted in altered clinical management, including 12 surgeries and 2 averted surgeries. In 3 of the 29, delayed diagnoses were associated with fixed pulmonary vascular disease, hypoxemic spells, and vascular collapse with severe metabolic acidosis. This study reveals a high incidence of diagnostic errors in pediatric echocardiograms performed in community-based adult laboratories, despite a preponderance of patients with simple diagnoses or no heart disease.

Children with heart murmurs: can ventricular septal defect be diagnosed reliably without an echocardiogram?

OBJECTIVES

This study was undertaken to determine the accuracy of expert examination for ventricular septal defect (VSD) among children with a heart murmur.

BACKGROUND

Because the frequency and nature of errors that might be made by reliance solely on expert examination for diagnosis of VSD are speculative, the role of echocardiography in such diagnosis is controversial.

METHODS

Two hundred eighty-seven consecutive previously unevaluated pediatric subjects were enrolled in the study. For each child, the pediatric cardiologists prospectively recorded a working diagnosis and their level of confidence in the diagnosis, categorizing any VSD diagnosed as small or moderate to large. After echocardiography, VSDs were subcategorized by location and requirement for treatment as minor, intermediate or major. Receiver-operating characteristic (ROC) curves described the accuracy of the clinical examination.

RESULTS

Seventy-three subjects had a VSD (minor in 52, intermediate in 10 and major in 11). ROC areas (1.0 = perfect discrimination, 0.5 = indiscriminate) were minor VSD 0.92 +/- 0.02 and major/intermediate VSD 0.69 +/- 0.07 (p = 0.0016). Four of 52 minor VSDs were not identified at any level of suspicion; the clinical diagnoses were moderate to large VSD in two patients and atrial septal defect and unlimited differential diagnosis in one patient each. Fourteen of 235 patients without a minor VSD were believed with confidence to have a small VSD, but the final diagnosis was intermediate VSD in 4, innocent murmur in 3, major VSD in 2, pulmonary stenosis in 2 and subaortic membrane, atrial septal defect and mitral regurgitation in 1 patient each.

CONCLUSIONS

Almost all minor VSDs are recognized without echocardiography; however, errors can occur even when an expert examiner is confident. Clinical recognition of an intermediate or major VSD is less accurate than clinical recognition of a minor VSD. Failure to distinguish VSDs of major or intermediate importance from minor VSDs is a weakness of the expert clinical examination.