دانلود رایگان مقاله مسئله فیبریلاسیون دهلیزی در بیماران دیالیزی

The burden of atrial fibrillation (AF) and the risk of stroke are high in dialysis patients. The decision to use anticoagulation rests heavily on effective risk stratification. Because both the pathophysiology of the disease and the response to therapy differ in dialysis, data from the general population cannot be extrapolated. The effect of vitamin K antagonists (VKAs) on the risk of stroke in dialysis patients with AF has not been studied in randomized trials. The available observational data provide contradictory results, reflecting differences in the degree of residual confounding, quality of international normalized ratio control, and stroke characterization. Dialysis patients have a high baseline bleeding risk. It remains unclear to what extent VKAs affect the overall bleeding propensity, but they may significantly increase the risk of intracerebral hemorrhage. Vascular calcifications are extremely prevalent in dialysis patients and independently associated with an adverse outcome. Vitamin K antagonists inhibit the activity of key anticalcifying proteins and may thus compound the risk of vascular calcification progression in dialysis. In the absence of evidence-based guidelines for anticoagulation in dialysis patients with AF, we provide recommendations to assist clinicians in individualized risk stratification. We further propose that new oral anticoagulants may have a better benefit-risk profile in dialysis patients than VKA, provided appropriate dose reductions are made. New oral anticoagulant may yield more on-target anticoagulation, reduce the risk of intracerebral bleeding, and not interfere with vascular calcification biology. Clinical trials with new oral anticoagulant in dialysis patients are eagerly awaited, to reveal whether these assumptions can be confirmed.

Conclusion

Patients with CKD and in particular those on dialysis differ from the general population for their increased risk of both ischemic and bleeding events, and propensity to develop vascular calcification. These peculiarities profoundly alter the benefit-risk ratio of VKA and preclude the simple extrapolation of guidelines from the general population. In the absence of RCT that delineate effective risk stratification in dialysis patients with AF, clinicians are currently left with little but their common sense to decide whether or not to start or continue VKA in their patients. Pending the development of a dialysis-specific stroke risk score that takes into account the actual determinants of stroke in this population, clinicians should know that AF remains important among the risk factors for stroke in dialysis patients, albeit less consistently than in the general population. Unfortunately, none of the available bleeding risk scores have a better predictive power than the simple assessment of history of gastrointestinal bleeding. In the absence of a dialysis-specific bleeding risk score, caution with VKA is warranted in frail, elderly patients, particularly when they have a history of major bleeding. When the decision to initiate VKA is made, the dose of heparin during dialysis should be minimized, and if the patient is already taking antiplatelet agents, their indication should be reevaluated. Finally, VKA should be avoided in patients with clinical evidence of vascular calcifications. Taken together, the threshold to initiate VKA in dialysis patients should probably be much higher than in the general population. New oral anticoagulants may have a more favorable risk-benefit ratio than VKA in dialysis patients, with the unassailable condition that appropriate dosing be implemented. So far, no clear dosing strategies are available for dialysis patients, except for rivaroxaban.59 We look forward to a carefully designed clinical trial with NOACs in dialysis patients with AF,65 providing data to support or dispute the assumption that they may have benefits in this population. Ideally, prospective validation in a large patient cohort of a (as yet to develop) dialysis-specific stroke and bleeding risk score should precede the conduction of such a trial.