Handheld Echocardiography Saves the Brain: A Serendipitously Found Left Ventricular Thrombus.

Handheld echocardiography (HHE) is an emerging technology with potential to alter routine clinical practice. Our institution has adopted the use of HHE devices for both teaching and patient care. However, the appropriate clinical scope of HHE continues to be controversial, and the literature is largely devoid of prognosis-altering applications. We report the diagnosis of left ventricular (LV) thrombus with HHE. A 75-year-old man presented with a large anteroapical ST-elevation myocardial infarction (MI). Initial transthoracic echocardiography (TTE) after percutaneous intervention showed no LV thrombus. Before his hospital discharge, HHE was performed and showed LV thrombus. The finding substantially changed the patient's treatment and prognosis; he was discharged with warfarin. This observation will help guide further inquiry into the proper clinical role of HHE.

ABBREVIATIONS

FoCUS, Focus Cardiac Ultrasound

HHE, handheld echocardiography

LV, left ventricular

MI, myocardial infarction

TE, traditional echocardiography

TTE, transthoracic echocardiography

INTRODUCTION

Handheld echocardiography (HHE) is an emerging technology with many potential clinical applications. Traditional echocardiography (TE) is the gold standard for noninvasive assessment of cardiac structure and function. However, it is expensive and does not generally allow for rapid bedside decisions. In contrast, HHE can be conceived as a form of point-of-care testing wherein data are gathered, analyzed, and acted on by a provider in a single clinical encounter. Its efficacy and reliability were questioned initially. Nevertheless, many clinicians started applying it in their daily practice and its use has expanded to other developed countries.

In a study comparing comprehensive echocardiography between the two modalities, Cullen et al.,[1] did find discordant findings in 27% of patients; however, the most discordant finding was in identification of regional wall abnormalities. In another recent study, HHE was compared with the physical examination in detection of cardiac pathologic characteristics, and HHE was significantly more accurate. Importantly, HHE also had a higher negative predictive value, suggesting the prospect of lower downstream costs.[2]

Nonetheless, the clinical scope of HHE continues to be ill-defined. The literature lacks reports wherein HHE substantially altered a patient's prognosis. We report such a case.

CASE REPORT

A 75-year-old man with diabetes mellitus presented to our emergency department with acute ST-elevation myocardial infarction (MI). Electrocardiography showed ST-segment elevation in the anterolateral leads. Coronary angiography showed proximal occlusion of the left anterior descending artery. Following thrombectomy and angioplasty, two drug-eluting stents were placed with ensuing thrombolysis in MIIII flow across the lesion. The patient was admitted to the intensive care unit under the care of the cardiology service.

The initial clinical course was unremarkable. The patient had no new symptoms after intervention. His cardiac enzyme levels normalized, and repeat electrocardiography showed improving ST-segment elevations. Transthoracic echocardiography (TTE) on hospital day 2 showed an ejection fraction of 40% with abnormal wall motion at the mid and apical left ventricular (LV) segments [Figure 1]. We planned to discharge the patient on hospital day 4 with aspirin, clopidogrel, metoprolol tartrate, lisinopril, and atorvastatin.

Figure 1

Transthoracic echocardiography, hospital day 2. (a) Short axis, apex. (b) Apical two-chamber view. Ejection fraction is 40% with abnormal wall motion at mid and apical left ventricular segments and no evidence of left ventricular thrombus. V indicates ventral.

Before discharge, the cardiology team performed a limited TTE with a handheld device (Vscan GE-GM000100; General Electric Co). We found an apical LV thrombus, which had not been present 2 days earlier [Figure 2]. A formal TTE confirmed the thrombus, measuring 1.9 × 1.5 cm [Figure 3]. Treatment with heparin and warfarin was started, and the patient was discharged several days later with a therapeutic international normalized ratio.

Figure 2

Handheld echocardiography, hospital day 4, before anticipated hospital discharge. (a) Short axis, apex. (b) Short axis, apical two-chamber view. These views show a new apical thrombus (arrows). V indicates ventral.

Figure 3

Transthoracic echocardiography, hospital day 4. (a) Short axis, apex. (b) Short axis, apical two-chamber view. These views confirm an apical thrombus (arrows). V indicates ventral.

DISCUSSION

HHE is an emerging technology whose clinical scope has yet to be defined. Experts have questioned the exuberance surrounding HHE. Their concern is that physicians will be prone to over diagnosis with resultant unnecessary invasive testing, as well as underdiagnosis with inappropriate ruling out of serious pathologic factors.[3] Yet, all diagnostic methods suffer from this phenomenon, including the simple stethoscope. The task, then, is to study how well HHE can detect specific pathologic conditions through measurement of its specificity and sensitivity. But what pathologic factor should be targeted for study? Cases such as the present one may help form the parameters of future inquiry.

Compared with traditional TTE, HHE has both device and user limitations. The images have lower resolution and generally Doppler imaging is unavailable, though newer generation devices do have Doppler capabilities. Generally, these devices include M-mode. From a user perspective, most users of HHE are not experts in the acquisition and interpretation of echocardiography. However, the advantages are potentially many. Interpretation is made at the time of acquisition, yielding a similar workflow to the classic physical examination. Images and video can be saved for review. The devices are truly pocket-sized and the technology continues to improve with successive generations.

In our experience, HHE has proven useful for both clinical management and teaching. At our institution, medical residents are formally taught to answer “yes or no” questions concerning cardiac function and structure. These questions include recognizing grossly impaired LV function, pericardial effusion, and inferior vena cava dilatation. Residents are encouraged to practice these skills by routinely carrying the HHE devices during rounds and incorporating HHE into the physical examination, under the supervision of attending cardiologists. The technical training is similar in scope to the Focus Cardiac Ultrasound (FoCUS), articulated by the European Association of Cardiovascular Imaging.[4] However, our experience with the HHE device is that use might be safely and effectively expanded beyond emergency and critical situations, the use case for the FoCUS training.

In the present case, we report how HHE meaningfully changed the treatment of this patient who presented with an ST-segment elevation MI and how HHE ultimately improved his prognosis. Recent guidelines give a tepid Grade 2c recommendation for empirical treatment with warfarin and dual antiplatelet therapy for patients with anterior MI status post drug-eluting stent placement and an ejection fraction less than 40%. Yet, this patient's ejection fraction had measured greater than 40%. Furthermore, addition of warfarin is thought to reduce stroke by only seven events in 1,000 patients. However, if an LV thrombus is positively diagnosed, then 44 fewer strokes would occur among 1,000 patients.[5]

Without this surprising finding at the bedside, we would not have subjected the patient to the higher bleeding risk associated with anticoagulation. Based on this case, a novel clinical application of HHE may be post-MI surveillance for well-known complications. Future studies are necessary on the sensitivity and specificity of HHE for specific pathologic conditions. However, this case demonstrates the potential practice-changing power of what has been deemed by some experts to be the stethoscope of the future.