P122: The evaluation of various point of care ultrasound features in Stanford type A aortic dissections

Abstract

Introduction: Type A aortic dissection(AD) is one of the most lethal diseases in medicine. Its mortality rate increases 1-2% per hour from the onset of symptoms to treatment. Timely diagnoses of ADs, therefore, are crucial to improve survival and decrease morbidity. There are various proposed clinical guidelines to help emergency physicians decide when a CTA is urgently needed with most widely quoted being the validated Aortic Dissection Detection Risk Score(ADD-RS) recommended by the American Heart Association. The addition of D-Dimer for further risk stratification has also been entertained. A recent article published in the American Journal of Emergency recommends using point of care ultrasound(POCUS) to expedite diagnosis. With the rising use of POCUS in the emergency department, it can be the missing link to timely AD diagnoses. This project aims to elucidate the prevalence of positive POCUS findings (pericardial effusion and dilated aortic root) in type A AD via a retrospective chart review. Methods: This study is a retrospective chart review of 200 patients with the diagnosis of AD treated at Southlake Regional Hospital. We included patients diagnosed with type A AD and excluded those diagnosed with type B AD. We collected data on their demographics, ADD-RS scores, investigation results, treatments, and clinical outcomes. The main focus of the chart review was on the presence of pericardial effusion or dilated aortic root on echocardiograms. Binomial statistical analysis was used to analyze the collected data. Results: We identified 126 patients with type A AD out of 200 charts reviewed. Thirteen (14% CI 8-23%, n = 93 p = 0.05) had wide mediastinum on their chest X-rays; twenty (95% CI 75-100%, n = 21 P = 0.05) had elevated D-dimer levels; and ninety-one (72% CI 64-80%, n = 126 p = 0.05) had positive ADD-RS. Only 88 out of 126 AD cases had documented echocardiograms. Sixty-eight (77% CI 67-86%, n = 88 p = 0.05) had either pericardial effusions or dilated aortic roots on their echocardiograms. Eighty-one (92% CI 84-95%, n = 88 p = 0.05) had either positive ADD-RS or positive echocardiogram findings, which is 20 (23% CI 14-33%, n = 88 P = 0.05) more cases than ADD-RS would have picked up alone. Conclusion: The absence of both pericardial effusion and dilated aortic root on echocardiogram in combination with a negative ADD-RS has a high sensitivity for ruling out type A AD. Our data support further research into the use of POCUS to expedite the diagnosis of type A AD in the emergency department.