D-dimer as a Rule-Out for Aortic Dissection.

Introduction Acute aortic dissection (AAD) represents a significant diagnostic challenge with a high mortality rate if not treated promptly. This challenge arises from the diverse clinical presentations of AAD, and its symptom overlap with other medical conditions. Although both helical CT and transesophageal echocardiography are reliable diagnostic tools for AAD, they are not feasible for every suspected case. Furthermore, limited research on D-dimer's utility in ruling out AAD has been conducted due to the condition's rarity. Methods This study utilizes the TriNetX database (https://trinetx.com/), encompassing data from 54 healthcare organizations across the United States over the past two decades from 85 million patients. The objective is to evaluate the sensitivity of an elevated D-dimer level in diagnosing AAD across a much larger patient cohort than previously studied. Results Retrospectively analyzing this dataset, there were 1,319 patients identified with a confirmed AAD who had undergone D-dimer testing within a day of diagnosis. Of these, 1,252 patients exhibited D-dimer levels exceeding 400 ng/ml while 1,227 had levels surpassing 500 ng/ml. Notably, a D-dimer cutoff of 400 ng/ml demonstrated a sensitivity of 0.949 while a 500 ng/ml cutoff yielded a sensitivity of 0.930. Conclusion This large retrospective cohort study demonstrates that a blood D-dimer level is highly sensitive in assaying for AAD. The D-dimer levels analyzed showed a remarkable sensitivity in ruling out AAD, avoiding the need for more invasive testing in low-risk patients.

What echocardiographic findings suggest a pericardial effusion is causing tamponade?

BACKGROUND: Pericardial tamponade is neither a clinical nor an echocardiographic diagnosis alone. The echocardiogram carries diagnostic value and should be performed when there is suspicion for tamponade based on the history and physical exam. A pericardial effusion uncovered on point-of-care ultrasound (POCUS) may be mistaken for tamponade and thereby lead to inappropriate and invasive management with pericardiocentesis. OBJECTIVE: This narrative review will summarize the echocardiographic findings and associated pathophysiology that support the diagnosis of pericardial tamponade. It will provide a succinct description of the core findings for which emergency physicians should evaluate at the bedside, along with potential pearls and pitfalls in this evaluation. Labeled images and video clips are included. DISCUSSION: The core echocardiographic findings of pericardial tamponade consist of: a pericardial effusion, diastolic right ventricular collapse (high specificity), systolic right atrial collapse (earliest sign), a plethoric inferior vena cava with minimal respiratory variation (high sensitivity), and exaggerated respiratory cycle changes in mitral and tricuspid valve in-flow velocities as a surrogate for pulsus paradoxus. CONCLUSION: The emergency physician must recognize and understand the core echocardiographic findings and associated pathophysiology that suggest pericardial tamponade. Together with the history and clinical exam, these findings can help make the overall diagnosis and determine management.