[Anticoagulation in patients with chronic kidney disease : Recommendations from the working group "Heart-Kidney" of the German Cardiac Society and the German Society of Nephrology]

Laboratory Monitoring of Heparin Anticoagulation in Hemodialysis: Rationale and Strategies

Unfractionated heparin (UFH) and low-molecular-weight heparins (LMWHs) are commonly used to prevent clotting of the hemodialysis extracorporeal circuit and optimize hemodialysis adequacy. There is no consensus on the optimal dosing for UFH and LMWHs during hemodialysis. In clinical practice, semiquantitative clotting scoring of the dialyzer and venous chamber may help to guide UFH and LMWH dose adjustment. Laboratory monitoring has not been shown to improve clinical outcomes and is therefore not routinely indicated in most hemodialysis patients. It might, however, be considered in select patients, such as those with extremes of body weight or history of repeated clotting or bleeding. Methods for laboratory monitoring include the activated partial thromboplastin time, activated clotting time, and antifactor Xa assays for UFH and antifactor Xa assay for LMWHs. Target ranges for anticoagulation in hemodialysis have been suggested but not clearly defined. When utilizing these tests, issues such as availability, standardization, interfering factors, and interpretation must be considered. In this narrative review, we discuss the rationale and methods of monitoring anticoagulation in hemodialysis.

Gerinnungsmanagement in der schweren, fortgeschrittenen Niereninsuffizienz

Patienten mit chronischer Niereninsuffizienz (CKD) haben ein hohes Risiko für nicht valvuläres Vorhofflimmern (NVAF) und häufig ein höheres Risiko für venöse Thromboembolien (VTE) aufgrund ihrer Grunderkrankungen wie z. B. Diabetes. Bisher kamen Vitamin-K-Antagonisten (VKA) auch bei diesen Patienten in Deutschland zum Einsatz. VKA haben ein erhöhtes Blutungsrisiko und werden als Risikofaktor für eine Verschlechterung der Nierenfunktion und/oder Gefäßsituation (Athero- und Mediasklerose) von Patienten diskutiert. Aus diesen Gründen und den vorliegenden Studiendaten werden deshalb direkt wirkende orale Antikoagulanzien (DOAC) auch bei Patienten mit NVAF und CKD (G1–G3) in den Leitlinien empfohlen. Allerdings kann keine klare Empfehlung für den Einsatz von DOAC bei Dialysepatienten gegeben werden. Heparine spielen in diesem Zusammenhang nur eine untergeordnete Rolle.

Direct Oral Anticoagulants in Patients with Atrial Fibrillation and Renal Dysfunction

Atrial fibrillation and renal dysfunction often coexist, each disorder may predispose to the other and contribute to worsening prognosis. Both atrial fibrillation and chronic kidney disease are associated with increased risk of stroke and thromboembolic complications. Oral anticoagulation for stroke prevention is therefore recommended in patients with atrial fibrillation and decreased renal function. Each direct oral anticoagulant has unique pharmacologic properties of which clinician should be aware to optimally manage patients. The doses of direct oral anticoagulants require adjustment for renal function. There is debate regarding which equation, the Chronic Kidney Disease Epidemiology (CKD-EPI) equation vs. the Cockcroft-Gault equation, should be used to estimate glomerular filtration rate in patients with atrial fibrillation treated with direct oral anticoagulants. Our review tries to find arguments for benefit of direct oral anticoagulants in patients with renal dysfunction.

[Cardiovascular diagnostic testing in advanced chronic kidney disease: which tests are useful?]

Against the background of drastically increased cardiovascular comorbidity in patients with chronic kidney disease (CKD), an effective cardiovascular diagnostic approach appears essential. However, patients with CKD are often underdiagnosed. Prospective randomized studies showing an improved outcome for cardiovascular diagnostic in patients with CKD are limited. Special attention is paid to stress diagnostics in CKD patients. Guidelines recommend cardiovascular diagnostic evaluation prior to inclusion on the transplantation waiting list.

[Anticoagulation in patients with non-valvular atrial fibrillation (nvAF) and chronic kidney disease (CKD)]

Due to the associated risk of stroke, non-valvular atrial fibrillation (nvAF) is a major indication for oral anticoagulation. Many patients suffer from chronic kidney disease (CKD), which increases the risk for stroke and for bleeding. Vitamin K antagonists (VKA) receive only cautious recommendations in guidelines for patients with CKD and nvVHF due to heterogeneous study results; their summaries of product characteristics contain contraindications for patients with manifest CKD. Novel oral anticoagulants (NOACs) have been investigated and are approved in CKD patients with a creatinine clearance (CrCl) ≥ 25 or 30 ml/min, factor Xa inhibitors can be used also if CrCl is > 15 ml/min. NOACs show an advantageous benefit-risk profile compared to VKA in reducing stroke, other thromboembolic events and death on the one hand and occurrence of bleedings on the other, and are recommended by the current ESC guidelines.

Oral Anticoagulation in Chronic Kidney Disease and Atrial Fibrillation

BACKGROUND

Cardiological societies recommend, in their guidelines, that patients with atrial fibrillation and an intermediate (or higher) risk of stroke and systemic embolization should be treated with oral anticoagulant drugs. For patients who do not have mitral valve stenosis or a mechanical valve prosthesis, non-vitamin-K dependent oral anticoagulants (NOAC) are preferred over vitamin K antagonists (VKA) for this purpose. It is unclear, however, whether patients with chronic kidney disease and atrial fibrillation benefit from oral anticoagulation to the same extent as those with normal kidney function. It is also unclear which of the two types of anti - coagulant drug is preferable for patients with chronic kidney disease; NOAC are, in part, renally eliminated.

METHODS

This review is based on pertinent publications retrieved by a selective literature search, and on international guidelines.

RESULTS

Current evidence suggests that patients with atrial fibrillation who have chronic kidney disease with a glomerular filtration rate (GFR) above 15 mL/ min/1.73 m² should be treated with an oral anticoagulant drug if they have an at least intermediate risk of embolization, as assessed with the CHA2DS2-VASc score. For patients with advanced chronic kidney disease (GFR from 15 to 29 mL/ min/1.73 m²), however, this recommendation is based only on registry studies. For dialysis patients with atrial fibrillation, decisions whether to give oral anticoagulant drugs should be taken on an individual basis, in view of the elevated risk of hemorrhage and the unclear efficacy of such drugs in these patients. The subgroup analyses of the NOAC approval studies show that, for patients with atrial fibrillation and chronic kidney disease with a creatinine clearance of >25-30 mL/min, NOAC should be given in preference to VKA, as long as the patient does not have mitral valve stenosis or a mechanical valve prosthesis. For those whose creatinine clearance is less than 25 mL/min, the relative merits of NOAC versus VKA are still debated.

CONCLUSION

The cardiological societies' recommendation that patients with atrial fibrillation should be given oral anticoagulant drugs applies to the majority of such patients who also have chronic kidney disease.

DOAC use in patients with chronic kidney disease

Direct oral anticoagulants (DOACs) are increasingly prescribed substances in patients with indication for effective anticoagulation. Patients with chronic kidney disease (CKD) have a high burden of cardiovascular risk and are more likely to develop atrial fibrillation (AF) than patients without CKD. Patients with mild to moderate CKD benefit from DOACs, especially when having intolerance to vitamin K-antagonists (VKA). DOACs may in some cases be considered in patients with rare renal disease and hypercoagulabilic state. DOACs are to a large extent eliminated by renal excretion. Since prospective randomised data in CKD patients are sparse, the decision for anticoagulative therapy is challenging especially in patients with severe renal impairment. The direct factor Xa-inhibitors are approved for use even in patients with an estimated glomerular filtration rate (eGFR) between 15 and 30 ml/min. Careful monitoring of renal function on a regular basis is essential before initiation and after start of DOAC, especially for patients at risk for acute renal failure (elderly, diabetics, patients with preexisting kidney disease). None of the DOACs is approved in CKD patients with end-stage-renal-disease (ESRD) with or without dialysis. DOACs are not recommended for kidney transplant patients under immunosuppression with calcineurin inhibitors. In these patients conventional therapy with VKA is the only option, which has to be monitored closely since it has potential adverse effects.