Koronare Stents, duale Antiplättchentherapie und die perioperative Problematik

Peribulbar anesthesia in 750 patients treated with oral anticoagulants

AIM

To check the safety of continuation of oral anticoagulants in ophthalmic procedures requiring a peribulbar anesthesia.

METHOD

A prospective case control study included 750 patients with oral anticoagulants in group A and 750 patients who had never been treated with oral anticoagulant in group B. Hemorrhages were graded as follows: 1) spot ecchymosis of eyelid and or subconjunctival hemorrhage; 2) eyelid ecchymosis involving half of the lid surface area; 3) eyelid ecchymosis all around the eye, no increase in intraocular pressure; 4) retrobulbar hemorrhage with increased intraocular pressure.

RESULTS

In group A, grade 1 was observed in 13 patients (1.74%) and grade 2 in 2 patients (0.26%). In group B, grade 1 was observed in 12 patients (1.6%) and grade 2 was absent. No 3 or 4 hemorrhage grade was encountered in both groups. There was not significant difference in grade 1 hemorrhage between both groups (P=0.21).

CONCLUSION

Oral anticoagulants were not associated with a significant increase in potentially sight-threatening local anesthetic complications.

Management of patients with risk factors

This review addresses concomitant diseases and risk factors in patients treated for diseases of the ears, nose and throat in outpatient and hospital services. Besides heart disease, lung disease, liver disease and kidney disease, this article also covers disorders of coagulation (including therapy with new oral anticoagulants) and electrolyte imbalance. Special attention is paid to the prophylaxis, diagnosis and treatment of perioperative delirium. It is also intended to help optimise the preparation for surgical procedures and pharmacotherapy during the hospital stay.

The perioperative management of treatment with anticoagulants and platelet aggregation inhibitors

BACKGROUND

When giving anticoagulants and inhibitors of platelet aggregation either prophylactically or therapeutically, physicians face the challenge of protecting patients from thromboembolic events without inducing harmful bleeding. Especially in the perioperative period, the use of these drugs requires a carefully balanced evaluation of their risks and benefits. Moreover, the choice of drug is difficult, because many different substances have been approved for clinical use.

METHOD

We selectively searched for relevant publications that appeared from 2003 to February 2013, with particular consideration of the guidelines of the European Society of Cardiology, the Association of Scientific Medical Societies in Germany (AWMF), the American College of Cardiology, and the American Heart Association.

RESULTS

Vitamin K antagonists (VKA), low molecular weight heparins, and fondaparinux are the established anticoagulants. The past few years have seen the introduction of orally administered selective inhibitors of the clotting factors IIa (dabigatran) and Xa (rivaroxaban, apixaban). The timing of perioperative interruption of anticoagulation is based on pharmacokinetic considerations rather than on evidence from clinical trials. Recent studies have shown that substituting short-acting anticoagulants for VKA before a procedure increases the risk of bleeding without lowering the risk of periprocedural thromboembolic events. The therapeutic spectrum of acetylsalicylic acid and clopidogrel has been broadened by the newer platelet aggregation inhibitors prasugrel and ticagrelor. Patients with drug eluting stents should be treated with dual platelet inhibition for 12 months because of the risk of in-stent thrombosis.

CONCLUSION

Anticoagulants and platelet aggregation inhibitors are commonly used drugs, but the evidence for their perioperative management is limited. The risks of thrombosis and of hemorrhage must be balanced against each other in the individual case. Anticoagulation need not be stopped for minor procedures.

Treatment algorithm for oral anticoagulant and antiplatelet therapy in epistaxis patients

Background and objectives:

There is currently little published guidance on the management of anticoagulant and antiplatelet medication in patients admitted with epistaxis. The routine practice of withholding such medication in an attempt to control the epistaxis is common in the UK. However, this practice is not evidence-based, is often unnecessary, and can be associated with significant morbidity. This study introduces a treatment algorithm for oral anticoagulant and antiplatelet therapy in epistaxis patients, validated through a completed audit cycle.

Methods:

One hundred patients admitted with epistaxis to the University Hospital Southampton NHS Foundation Trust were studied via a two-audit cycle covering the implementation of a new treatment algorithm formulated jointly by the otolaryngology and haematology departments.

Results:

On admission, 58 per cent of patients were taking some form of anticoagulant or antiplatelet medication. The number of patients having such medication withheld decreased significantly between the two audits, for all drugs studied (i.e. aspirin, clopidogrel and warfarin). There was no significant increase in re-bleeding or re-admission rates between the audits.

Conclusion:

Implementation of this treatment algorithm would help standardise management for epistaxis patients taking anticoagulant or antiplatelet drugs, and should reduce morbidity associated with unnecessary routine discontinuation of such medication.

[Perioperative management of patients with coronary stents in non-cardiac surgery]

In patients with coronary stents scheduled for surgery the question arises whether and how antiplatelet therapy should be continued. Risks of perioperative bleeding and of acute stent thrombosis have to be considered simultaneously. The bleeding risk depends primarily on the kind of surgery and on patient comorbidity. The risk of stent thrombosis is increased in these patients due to the thrombogenic surface of the stents. The main determinants are hereby the time duration after stent implantation, the kind of the stent [uncoated (bare-metal stent, BMS) or coated (drug-eluting stent, DES)], as well as angiographic and clinical patient factors. Therefore, perioperative antiplatelet therapy has to be individually adapted for each patient. Bridging with heparin is ineffective. Bridging with intravenous antiplatelet drugs during the perioperative interruption of oral antiplatelet therapy might be a potential procedure in high-risk patients. Whether bedside monitoring of antiplatelet therapy improves the perioperative management of these patients and reduces adverse outcome is object of current studies.

The effect of ex vivo anticoagulants on whole blood platelet aggregation

Pre- and intraoperative platelet function monitoring is increasingly recommended in order to detect risk factors for bleeding and to target coagulation management. The ideal anticoagulant for accurate platelet aggregometry remains controversial. The aim of this experimental trial was to compare platelet aggregability in whole blood stored in citrate, heparin and direct thrombin inhibitors. Whole blood was drawn from 11 healthy adult volunteers who had not taken any medication in the previous 14 days. Blood was stored in trisodium citrate, unfractionated heparin, melagatran, lepirudin and argatroban. Platelet aggregation was performed using the impedance aggregometer Multiplate (Dynabyte, Munich, Germany) with adenosine diphosphate (ADP), thrombin receptor activating peptide (TRAP), collagen, arachidonic acid and ristocetin as agonists. Samples were analysed immediately after blood sampling (baseline), as well as 30 and 120 min afterwards. At baseline there were no significant differences in aggregability between samples containing direct thrombin inhibitors and heparin. In contrast, aggregation in response to all agonists except for ristocetin was significantly impaired in citrated blood. During storage the response to arachidonic acid and collagen was maintained by direct thrombin inhibitors and heparin, whereas ADP-, TRAP- and ristocetin-induced aggregation varied considerably over time in all ex vivo anticoagulants tested. Pre-analytical procedures should be standardized because storage duration and anticoagulants significantly affect platelet aggregability in whole blood. For point-of-care monitoring with immediate analysis after blood withdrawal all tested direct thrombin inhibitors as well as unfractionated heparin can be used as anticoagulants whereas citrate is not recommended.