PC2137: A Case for Early Transesophageal Echocardiography in Native Mitral Valve Thrombus in a Pediatric Patient

Introduction: Embolic stroke represents a clinically significant proportion of cerebrovascular accidents. While recognized as a common source in adults, cardioembolic origin is far less often considered in the pediatric population. In this case report we evaluate the presentation and diagnostic workup of native-valve thrombus in children and adolescents.

Case Description: A 16-year-old male, 6’3” and 110kg, with history of MIS-C and CKD secondary to left renal infarct presented with acute onset dysarthria and right-sided weakness. He had MIS-C the year prior complicated by mitral valve (MV) thrombus and renal infarct. MV thrombus was treated with rivaroxaban and resolution was noted on transthoracic echocardiogram (TTE) three weeks into treatment. On presentation, imaging demonstrated multiple scattered ischemic foci consistent with embolic stroke. He was admitted to the PICU where TTE was negative for intracardiac thrombus with sufficient windows. Anticoagulation was held in preparation for a lumbar puncture. Unfortunately, he sustained acute right-sided paralysis with imaging demonstrating left MCA and ACA embolic occlusion requiring urgent thrombectomy. Transesophageal echocardiogram (TEE) at that time demonstrated a large, mobile pedunculated mass (23mm x 10mm) attached to the anterior MV leaflet not evident on prior TTE. Rivaroxaban was discontinued and the patient was started on warfarin with plan for life-long anticoagulation.

Discussion: Little has been published previously comparing the inherent benefits and pitfalls of TTE versus TEE in pediatrics. Mitral valve thrombus, especially on a structurally normal native heart valve, is an atypical finding in children and adolescents. Though atypical, the incidence of cardiac thrombus among children with ischemic stroke is 20% compared to 15% to 40% in adults.

Echocardiography is performed as standard workup for cardiac thrombus in both adults and children. The American Society of Echocardiography (ASE) generally recommends TTE-first examination; however, suggests stratifying for risk of intracardiac thrombus when considering initial choice of study. Per the ASE guidelines, they suggest both TTE and TEE as initial or supplemental test for evaluation of cardiovascular source of embolus without identified non-cardiac sources elsewhere. In adults, it has been well documented that TEE is superior to TTE in detecting intracardiac pathology such as vegetations. The sensitivity of TTE for vegetations when using TEE as gold standard was 55%. There is still a paucity of data in the pediatric population for sensitivity and specificity of TEE in identifying native mitral valve thrombus.

Conclusion: When evaluating a pediatric patient with increased pretest probability for valvular thrombus or poor windows on TTE, we argue for early TEE in an effort to expedite diagnosis. Earlier diagnosis in our patient may have prevented further organ damage. We acknowledge that TEE-first approach would not be appropriate in all patients but encourage pursuits of more clearcut guidelines for children and adolescents, especially ones considering patient age and size.