Prediction of aortic stenosis-related events in patients with systolic ejection murmur using pocket-sized echocardiography

A call to consider an aortic stenosis screening program

Aortic stenosis (AS) is the most common age-related valvular condition with a prevalence of 13.1% in patients older than 75 years of age. Based on the severity of AS and symptoms, current guidelines recommend interval monitoring with transthoracic echocardiogram (TTE). However, no guidelines exist regarding screening asymptomatic persons for AS. Prevalence of AS is comparable to conditions such as colorectal cancer, lung cancer, breast cancer, and abdominal aortic aneurysm where dedicated screening programs are offered resulting in reduction of overall morbidity and mortality. We review recent advancements in treatment options, and we propose an AS screening program for high-risk individuals without known history of AS including all persons over age 75 and persons aged 70 years and older with dialysis dependent end-stage renal disease (ESRD).

Screening for aortic stenosis using physical examination and echocardiography

Most patients with aortic stenosis (AS) can be treated with either traditional surgical aortic valve replacement or newly emerged transcatheter aortic valve implantation. Therefore, the early and appropriate detection of significant AS has become more important for avoiding overlooking patients who require treatment. AS is initially detected by the presence of a systolic ejection murmur (SEM). However, it is time-consuming and expensive for all subjects presenting with SEM to undergo comprehensive standard echocardiography using high-end ultrasound machines since the SEM is audible in a large proportion of elderly patients and is not specific for significant AS. Therefore, further physical examination and/or focused cardiac ultrasound (FoCUS) is required to determine whether patients with a SEM should be referred for standard echocardiography. One or more abnormal physical findings in addition to a SEM can rule out a certain proportion of normal cases without overlooking severe AS. Most of the previous studies suggesting the usefulness of FoCUS in screening for valvular heart disease only used visual impressions in their assessment of AS. By contrast, visual AS and calcification scores are good objective parameters in screening for AS with FoCUS. Patients with severe AS and patients with a high probability of AS-related events are rarely overlooked even if comprehensive standard echocardiography is performed only when either (or both) of the FoCUS scores is 3 or more. The appropriate combination of physical examinations and FoCUS to screen for AS is discussed in this review article.

Simple echocardiographic scoring in screening aortic stenosis with focused cardiac ultrasonography in the emergency department

BACKGROUND

No established methodology exists for diagnosis of aortic stenosis (AS) using focused cardiac ultrasound (FOCUS). We evaluated the diagnostic accuracy of our developed visual AS score for screening AS in an emergency department.

METHODS

Seventy-two emergency outpatients with suspected cardiovascular disease were studied. Emergency physicians assessed the visual AS score in addition to conducting the standard FOCUS, and then the aortic valve area index (AVAI) was measured by expert sonographers in the echocardiography laboratory. AVAI values >0.85 cm²/m², 0.6-0.85 cm²/m², and <0.6 cm²/m² were defined as no or mild AS, moderate AS, and severe AS, respectively.

RESULTS

Seventeen (24%) patients had moderate or severe AS. Visual AS scores assessed by emergency physicians and by expert sonographers showed excellent agreement (κ = 0.93), and a strong association was noted between the visual AS score assessed by emergency physicians and the AVAI assessed by expert sonographers (R = -0.71, p < 0.0001). A visual AS score ≥3 assessed by emergency physicians had a sensitivity of 82%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 95% for diagnosing moderate or severe AS. The prevalence of new-onset AS-related events during hospitalization was higher in patients with visual AS score ≥3 assessed by emergency physicians than in the remaining patients [7 (50%) vs. 2 (3%), p < 0.0001].

CONCLUSION

The visual AS score is a useful AS screening tool for emergency physicians who are not expert cardiologists.

Application of mobile health, telemedicine and artificial intelligence to echocardiography

The intersection of global broadband technology and miniaturized high-capability computing devices has led to a revolution in the delivery of healthcare and the birth of telemedicine and mobile health (mHealth). Rapid advances in handheld imaging devices with other mHealth devices such as smartphone apps and wearable devices are making great strides in the field of cardiovascular imaging like never before. Although these technologies offer a bright promise in cardiovascular imaging, it is far from straightforward. The massive data influx from telemedicine and mHealth including cardiovascular imaging supersedes the existing capabilities of current healthcare system and statistical software. Artificial intelligence with machine learning is the one and only way to navigate through this complex maze of the data influx through various approaches. Deep learning techniques are further expanding their role by image recognition and automated measurements. Artificial intelligence provides limitless opportunity to rigorously analyze data. As we move forward, the futures of mHealth, telemedicine and artificial intelligence are increasingly becoming intertwined to give rise to precision medicine.

A systematic review of pocket-sized imaging devices: small and mighty?

Introduction

Hand-held imaging devices are widely used in clinical practice and are a useful tool. There is no published review examining the diagnostic parameters achieved with these devices in clinical practice.

Methods

We searched three online medical literature databases (PubMed, EMBASE and MEDLINE) for all literature published up until January 2018. We selected studies that (1) were conducted in the adult population; (2) used a truly hand-held device; (3) featured sensitivities and/or specificities on the use of the hand-held scanner. We extracted and summarised the diagnostic metrics from the literature.

Results

Twenty-seven articles were excluded from the initial 56 relevant articles, as the device featured was not truly hand-held. Ultimately a total of 25 studies were analysed. Sixteen studies were carried out by experienced users, seven by users with little previous experience and two studies by nurses. High diagnostic parameters were achieved by all three groups when scanning cardiac pathology and intra-abdominal structures. Training of non-expert users varied, taking a mean of 21.6 h. These hand-held devices can change diagnoses at the bedside and be used as gate-keepers to formal echocardiography. Individual studies show them to be cost-effective.

Conclusion

Hand-held echocardiography is a useful tool in the hands of experts and novices alike. Studies conducted are highly heterogeneous making it difficult to pool data for the diagnostic metrics. Further studies with rigorous methodology are needed to evaluate the true diagnostic potential in the hands of non-experts and in the community as well as to validate training protocols.