(1135) McConnell Sign Without PE in a VV ECMO Patient

Introduction: Pulmonary emboli (PE) are responsible for significant morbidity and mortality in critically ill patients, especially those on extracorporeal membrane oxygenation (ECMO). Most diagnostic algorithms for PEs include transthoracic echocardiography (TTE). We present a patient on VV ECMO with TTE demonstrating the McConnell Sign. We review the predictive value of this finding for PEs.

Description: A 37-year-old man with diabetes and opioid use disorder presented with dyspnea and productive cough. He was found to have diabetic ketoacidosis and cavitary pneumonia, with blood cultures growing candida glabrata. Initial TTE demonstrated no abnormalities aside from an intrapulmonary shunt.

He worsened, requiring intubation and vasopressors. He remained hypoxic and underwent VV ECMO cannulation. A TTE following cannulation showed a severely dilated right ventricle (RV), depressed RV systolic function, and free wall hypokinesis with preserved apical motion. The reading cardiologist alerted the primary team of high probability of a PE; the patient had already been on anticoagulation because of poor lung flow on ECMO. CTA chest did not show PE but demonstrated dilated pulmonary arteries.

Discussion: The McConnell Sign of RV free wall akinesis with apical sparing was first described in a 1996 cohort study, with sensitivity and specificity for acute PE calculated as 77% and 96%, respectively (1). A subsequent, larger retrospective study of 161 patients found a sensitivity of 70%, specificity of 33%, positive predictive value of 67%, and negative predictive value 36%; similar values have also been seen in meta-analyses (2,3). Other measurements, such as the “60/60 sign,” may have greater predictive value for acute PEs on TTE, both alone and in conjunction with McConnell sign (4). Despite a lack of sensitivity or specificity, TTE remains useful in PE patients for prognostication and risk stratification and has inter-reader reproducibility (5-7).

Several other disease processes can cause regional RV dysfunction. Severe ARDS is known to cause RV dysfunction and is correlated with mortality (8). RV ischemia can present with McConnell Sign, as can other conditions that cause excessive preload or afterload (9,10). Our patient’s severe cavitary lesion likely led to elevated pressures and right-sided dilation.