Increase in the Size of an Intracardiac Thrombus during Dabigatran Therapy (110 mg b.i.d.) in an Acute Cardioembolic Stroke Patient

Aggressive early surgical strategy in patients with intracranial hemorrhage: a new cardiopulmonary bypass option

OBJECTIVE

We present a novel strategy in cardiac surgery with a cardiopulmonary bypass with low-dose heparin and Nafamostat mesylate as an anticoagulant (NM-CPB), which reduces postoperative neurological complications.

METHOD AND RESULTS

19 patients with a mean age of 63.6 ± 20.2 years (range 24-91) and an indication of early cardiac surgery with intracranial complication (ICC) underwent surgery with NM-CPB. The preoperative diagnoses included seven cases of infective endocarditis and six of left atrial appendage thrombosis. ICC were noticed in seven cases with hemorrhages (hemorrhagic infarction: n = 4, subarachnoid hemorrhage: n = 3) and 12 without hemorrhage (large infarction: n = 10, small-multiple infarction at the risk for hemorrhagic transformation: n = 2). The mean interval between a diagnosis and cardiac surgery was 1.1 ± 1.5 days in the ICH cases and 1.4 ± 1.4 days otherwise. In-hospital mortality was 5.3%. The mean CPB time was 146.7 ± 66.03 min, the mean dose of NM, heparin were 2.23 ± 1.59 mg/kg/hr and 56.8 ± 20.3 IU/kg, respectively. The mean activated clotting time (ACT) was 426.8 ± 112.4 s. No further intracranial bleeding and no new hemorrhages were observed after surgery.

CONCLUSIONS

In early cardiac surgery with ICC, especially with hemorrhage, NM-CPB reduced postoperative neurological complications. We plan to use NM-CPB to expand the indications and to establish an early aggressive treatment.

Left atrial appendage thrombus on full-dose dabigatran treatment: a case report

Background

Dabigatran is a direct competitive thrombin inhibitor approved for stroke prevention in non-valvular atrial fibrillation. At full-dose, dabigatran showed similar rates of bleedings and higher efficacy compared to warfarin.

Case summary

We report a case of acute ischaemic stroke in a patient treated with dabigatran 150 mg b.i.d. for atrial fibrillation. After an off-label treatment with idarucizumab, a humanized monoclonal antibody approved for dabigatran reversal, we performed a successful intravenous thrombolysis (IVT). Transoesophageal echocardiography showed a left atrial appendage (LAA) thrombus, despite full-dose dabigatran and an adequate therapy adherence.

Discussion

There are few cases of LAA thrombus during dabigatran treatment reported in literature till date. We analyse the possible pathogenetic mechanisms involved in dabigatran failure, including drug interactions and unexpected genetic variations interfering with dabigatran serum levels suggesting periodical assessment of direct Oral Anticoagulant levels. Furthermore, we confirm initial reports of safety and efficacy of intravenous thrombolysis after idarucizumab, in case of dabigatran failure.

THROMBOSIS OF LEFT ATRIAL APPENDAGE DURING THERAPY WITH DIRECT ORAL ANTICOAGULANT. CLINICAL CASE

The article presents a clinical observation of the left atrial appendage thrombosis in a 51-year-old female patient with a paroxysmal form of nonvalvular atrial fibrillation which occurred despite long-term anticoagulant therapy with apixaban in a full dose (5 mg b.i.d.), and the patient’s management. The patient was admitted with recurrent symptomatic paroxysm for more than 48 hours, because of which, in accordance with the recommendations, transesophageal echocardiography was performed before an emergency rhythm restoration. Thrombus in the left atrial appendage 0.5×1.03 cm in size was detected. It was decided to refrain from the immediate restoration of the rhythm due to the very high risk of thromboembolic complications. In connection with the categorical refusal of the patient from warfarin, it was decided to replace apixaban with another direct oral anticoagulant – dabigatran 150 mg bid for a period of 4 weeks followed by performing a control transesophageal echocardiographic study. As a result, no thrombus was found on control echocardiography. The particularity of this observation is concomitant hypertrophic cardiomyopathy and diabetes mellitus type 1 in this patient.

Resolution of Internal Carotid Arterial Thrombus by the Thrombolytic Action of Dabigatran: A first case report

Non-vitamin K antagonist oral anticoagulants (NOACs) have been reported to cause resolution of intracardiac thrombus, but there have been no reported cases of internal carotid arterial thrombus resolution.We report a case of a 76-year-old man in whom an internal carotid arterial thrombus resolved after administration of the NOAC dabigatran at a dose of 110  mg twice daily.This is the first reported case of carotid arterial thrombus resolution after oral intake of NOAC (direct thrombin and factor Xa inhibitors), to the best of our knowledge.We conclude that this case had major clinical significance because it might represent one of the multiple effects of NOACs.

Monitoring of dabigatran therapy using Hemoclot(®) Thrombin Inhibitor assay in patients with atrial fibrillation

Dabigatran, a new direct thrombin inhibitor, achieves strong anticoagulation that is more predictable than warfarin. Nevertheless, a patient on dabigatran therapy (DT) may suffer from thrombotic or bleeding events. The routine monitoring of DT is not recommended, and standard coagulation tests are not sensitive enough for the assessment of DT activity. The aim of this study was to examine the clinical usefulness of the Hemoclot(®) Thrombin Inhibitor (HTI) assay in the assessment of dabigatran plasma levels in patients with non-valvular AF. Nineteen patients (12 men, 7 women) on DT were included in this preliminary prospective observational study. Dabigatran was administrated twice daily in a two dose regimens: 150 mg (5 patients) and 110 mg (14 patients). Blood samples were taken for the assessment of trough and peak levels of dabigatran. Dabigatran concentrations were measured with the HTI assay. The average dabigatran trough level was 69.3 ± 55.5 ng/ml and the average dabigatran peak level was 112.7 ± 66.6 ng/ml. The dabigatran trough plasma concentration was in the established reference range in 15 patients and the dabigatran peak plasma concentration was in the established reference range in 9 patients, respectively. Despite the fact that the activated partial thromboplastin and thrombin times were generally changed (prolonged), these tests failed to identify the patients with too low or too high dabigatran concentrations. The study confirmed the high sensitivity of the HTI assay for the assessment of dabigatran plasma levels. When compared to standard coagulation tests, the HTI is a more suitable assay for the monitoring of patients treated with dabigatran. Monitoring of DT may be beneficial in selected patients; however, further studies will be needed for the final clarification of this issue.

Left atrial thrombus formation and resolution during dabigatran therapy: A Japanese Heart Rhythm Society report

BACKGROUND

Protocols on the use of novel oral anticoagulants for stroke prevention in patients with atrial fibrillation (AF) undergoing electrical cardioversion (ECV) are lacking.

AIM

The study was aimed at evaluating the efficacy of dabigatran (Dabi) treatment in preventing peri-ECV stroke.

METHODS

A retrospective survey of the incidence and fate of left atrial (LA) thrombus during Dabi therapy in patients with AF was conducted between December 2012 and January 2013 by the Japanese Heart Rhythm Society.

RESULTS

A total of 198 patients from 299 institutions underwent transesophageal echocardiography (TEE) to rule out LA thrombus before ECV. Of these, LA thrombus was found in eight patients (4%), who tended to be older (67.3 vs. 61.3 years, p=0.175), had higher CHADS2 scores (1.88 vs. 0.95, p=0.058), and a higher prevalence of prior stroke or transient ischemic attack (22.2% vs. 2.6%, p=0.034) than those without LA thrombus. Of the eight patients with LA thrombus, one had LA thrombus during a Dabi 150 mg b.i.d treatment, whereas the remaining seven were receiving 110 mg b.i.d for 3 weeks or longer. In 6 of the 8 patients with LA thrombus, a second TEE was performed, revealing complete resolution of LA thrombus in five; among these five patients, one received Dabi dosage of 150 mg b.i.d unchanged, two received an increased dosage from 110 mg to 150 mg b.i.d, and two were switched to warfarin. Two patients had a stroke 3 and 15 days after ECV, and one had a major large intestine bleeding episode during Dabi therapy.

CONCLUSIONS

LA thrombus developed in 4% of patients with AF receiving Dabi. Older patients with a higher CHADS2 score receiving a lower Dabi dosage were more likely to develop LA thrombus, which was resolved with a prolonged or increased dosage. A higher Dabi dosage may be more beneficial before ECV but prospective randomized studies would be needed to confirm these results.

Two-week administration of rivaroxaban resolved left atrial thrombus

An 89-year-old man visited our hospital complaining of palpitation. Electrocardiography showed atrial fibrillation, and transthoracic echocardiography demonstrated a mobile thrombus of 28.6 mm × 20.8 mm in the left atrium. Administration of a direct factor Xa inhibitor rivaroxaban (10 mg/day) was started. The thrombus reduced its size and disappeared completely 2 weeks after the commencement of rivaroxaban treatment. To our knowledge, this is the first case report that rivaroxaban successfully dissolved left atrial thrombus during a short period. Rivaroxaban might have a potential, not only to prevent de novo thrombus formation, but also to dissolve established thrombi by direct inhibition of free and thrombus-associated factor Xa. <Learning objective: The incidence of nonvalvular atrial fibrillation is increasing, and left atrial thrombus is the major cause of cardiogenic thrombo-embolism that we need to prevent. Recently, novel oral anticoagulants have been developed. The effects of these agents on intracardiac thrombus resolution have not been fully elucidated. Data from a large cohort study would be required to assess efficacy of novel oral anticoagulants for thrombus resolution.>.