A Case of Fatal Bleeding Following Emergency Surgery on an Ascending Aorta Intramural Hematoma in a Patient Taking Dabigatran

Impact of Atrial Fibrillation on In-Hospital Mortality and Stroke in Acute Aortic Syndromes

BACKGROUND

Acute aortic syndromes may present with a number of cardiovascular complications, including atrial fibrillation. We assessed the prevalence of atrial fibrillation in patients presenting with acute aortic syndromes and evaluated atrial fibrillation's association with in-hospital mortality and stroke.

METHODS

Consecutive patients with acute aortic syndromes admitted to a single tertiary care center from January 2015 to March 2020 were included. We identified patients with atrial fibrillation on the presenting electrocardiogram.

RESULTS

A total of 309 patients with acute aortic syndromes were included in our analyses: 148 (48%) presented with Stanford type A and 161 (52%) with Stanford type B acute aortic syndromes. Twenty-seven (8.7%) patients had atrial fibrillation on the presenting electrocardiogram: 12 (44%) with type A and 15 (56%) with type B acute aortic syndromes. Patients with atrial fibrillation were older, more likely to be white, had a higher frequency of history of cancer, peripheral artery disease, cerebrovascular disease, and heart failure with preserved ejection fraction, compared with those without atrial fibrillation. Acute aortic syndromes patients with atrial fibrillation had higher frequencies of in-hospital mortality compared with those without atrial fibrillation (40.7% vs 12.4%, P < .0001). However, stroke frequencies did not differ between the 2 groups.

CONCLUSION

In patients presenting with acute aortic syndromes and atrial fibrillation, we observed higher frequencies of in-hospital mortality, without differences in the frequencies of stroke.

Point-of-care detection and differentiation of anticoagulant therapy - development of thromboelastometry-guided decision-making support algorithms

Background

DOAC detection is challenging in emergency situations. Here, we demonstrated recently, that modified thromboelastometric tests can reliably detect and differentiate dabigatran and rivaroxaban. However, whether all DOACs can be detected and differentiated to other coagulopathies is unclear. Therefore, we now tested the hypothesis that a decision tree-based thromboelastometry algorithm enables detection and differentiation of all direct Xa-inhibitors (DXaIs), the direct thrombin inhibitor (DTI) dabigatran, as well as vitamin K antagonists (VKA) and dilutional coagulopathy (DIL) with high accuracy.

Methods

Following ethics committee approval (No 17–525-4), and registration by the German clinical trials database we conducted a prospective observational trial including 50 anticoagulated patients (n = 10 of either DOAC/VKA) and 20 healthy volunteers. Blood was drawn independent of last intake of coagulation inhibitor. Healthy volunteers served as controls and their blood was diluted to simulate a 50% dilution in vitro. Standard (extrinsic coagulation assay, fibrinogen assay, etc.) and modified thromboelastometric tests (ecarin assay and extrinsic coagulation assay with low tissue factor) were performed. Statistical analyzes included a decision tree analyzes, with depiction of accuracy, sensitivity and specificity, as well as receiver-operating-characteristics (ROC) curve analysis including optimal cut-off values (Youden-Index).

Results

First, standard thromboelastometric tests allow a good differentiation between DOACs and VKA, DIL and controls, however they fail to differentiate DXaIs, DTIs and VKAs reliably resulting in an overall accuracy of 78%. Second, adding modified thromboelastometric tests, 9/10 DTI and 28/30 DXaI patients were detected, resulting in an overall accuracy of 94%. Complex decision trees even increased overall accuracy to 98%. ROC curve analyses confirm the decision-tree-based results showing high sensitivity and specificity for detection and differentiation of DTI, DXaIs, VKA, DIL, and controls.

Conclusions

Decision tree-based machine-learning algorithms using standard and modified thromboelastometric tests allow reliable detection of DTI and DXaIs, and differentiation to VKA, DIL and controls.

Trial registration

Clinical trial number: German clinical trials database ID: DRKS00015704.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12959-021-00313-7.

Viscoelastic testing inside and beyond the operating room

Hemorrhage is a major contributor to morbidity and mortality during the perioperative period. Current methods of diagnosing coagulopathy have various limitations including long laboratory runtimes, lack of information on specific abnormalities of the coagulation cascade, lack of in vivo applicability, and lack of ability to guide the transfusion of blood products. Viscoelastic testing offers a promising solution to many of these problems. The two most-studied systems, thromboelastography (TEG) and rotational thromboelastometry (ROTEM), offer similar graphical and numerical representations of the initiation, formation, and lysis of clot. In systematic reviews on the clinical efficacy of viscoelastic tests, the majority of trials analyzed were in cardiac surgery patients. Reviews of the literature suggest that transfusions of packed red blood cells (pRBC), plasma, and platelets are all decreased in patients whose transfusions were guided by viscoelastic tests rather than by clinical judgement or conventional laboratory tests. Mortality appears to be lower in the viscoelastic testing groups, despite no difference in surgical re-intervention rates and massive transfusion rates. Cost-effectiveness studies also seem to favor viscoelastic testing. Viscoelastic testing has also been investigated in small studies in other clinical contexts, such as sepsis, obstetric hemorrhage, inherited bleeding disorders, perioperative thromboembolism risk assessment, and management of anticoagulation for patients on mechanical circulatory support systems or direct oral anticoagulants (DOACs). While the results are intriguing, no systematic, larger trials have taken place to date. Viscoelastic testing remains a relatively novel method to assess coagulation status, and evidence for its use appears favorable in reducing blood product transfusions, especially in cardiac surgery patients.