HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

Correspondence to:

ARTICLES: David J. Blacker, Eelco F.M. Wijdicks, and Robyn L. McClelland Stroke risk in anticoagulated patients with atrial fibrillation undergoing endoscopy Neurology 2003; 61: 964-968 [Abstract] [Full text] [PDF]

Correspondence: Submit a response to this article

Correspondence published:

Reply to Enis

Eelco Wijdicks, MD, David Blacker   (3 December 2003)

Stroke risk in anticoagulated patients with atrial fibrillation undergoing endoscopy

Joseph Enis   (3 December 2003)

Reply to Enis 3 December 2003
Eelco Wijdicks, MD, Mayo Clinic Rochester, MN, David Blacker Send Correspondence to journal: Re: Reply to Enis wijde{at}mayo.edu Eelco Wijdicks, MD, et al.	We thank Dr Enis for his response and find his data interesting. Including the details of our atrial fibrillation (AF) patients not previously prescribed warfarin, may have been of interest, but would have meant analyzing another 4150 patient records. We felt it important to highlight that the stroke risk was higher than what might be calculated from theoretical models [1], since clinicians previously only had these to guide their decisions. Our discussion covers some of the reasons why our calculated periprocedural stroke risk may be higher, and includes comments on “rebound hypercoagulability”. [2] The data presented by Dr Enis may suggest that this is an important mechanism. References 1. Kearnon C, Hirsh J. Current concepts: management of anticoagulation before and after elective surgery. N Engl J Med 1997;336:1506-1511. 2. Genewein U, Haeberli A, Straub P. Rebound after cessation of oral anticoagulant therapy: the biochemical evidence. Br J Haematol 1996;92:479-485.
Stroke risk in anticoagulated patients with atrial fibrillation undergoing endoscopy 3 December 2003
Joseph Enis, The St. George Hospital, Sydney, AUSTRALIA 68 Balfour Road, Rose Bay 2029 Sydney, AUSTRALIA Send Correspondence to journal: Re: Stroke risk in anticoagulated patients with atrial fibrillation undergoing endoscopy joenis{at}tpg.com.au Joseph Enis	The retrospective analysis by Blacker et al [1] outlines the inherent risks in suspending anticoagulation, prior to a procedure, in patients with AF. Inclusion of data on those AF patients not previously anticoagulated might have served as a better control than relying on “theoretical risk” from earlier studies. I prospectively collected preliminary data from a single hospital over a nine-month period in 2002. Of patients hospitalized with ischemic stroke, 21 had stopped taking their anticoagulant prior to presentation. Thirteen of these had AF and all 13 were originally anticoagulated to prevent cardiac embolic stroke. Remarkably, five of these 13 had stroke within 30 days, indeed all five within just 10 days, of stopping their anticoagulant. The remaining eight of these 21 patients might be considered controls, as they had been prescribed anticoagulants for other reasons (e.g., DVT prophylaxis). Here, stroke followed within 30 days in only one case. Those patients with AF most likely to suffer an early stroke were those who had had a previous, often distant, stroke. Surprisingly, old age, hypertension and diabetes failed to identify those at greatest risk – but this is a small sample. Such dramatic early clustering of events has not previously been reported in patients with AF who were unprotected by anticoagulation, even after recent stroke. This raises the possibility of “rebound hypercoagulability”. It is instructive to look for evidence that might support this phenomenon in the earlier major trials of anticoagulation for patients with NVAF. Only those trials using higher target INRs reported a similar experience, possibly because bleeding as a complication of treatment, and hence the need to suspend anticoagulation, was more frequent. Of patients initially assigned to anticoagulant therapy, two of six developed an ischemic stroke within five days [2], and three of 11 within seven days [3], of stopping their anticoagulant. Two of four cases [4], and one of six [5] occurred during temporary discontinuation of treatment. With increasing use of anticoagulants in patients with NVAF, and the frequency with which these are temporarily suspended in this elderly population, the easily overlooked problem may be far greater than we imagine. Further confirmation of this association may help promote use of lower target INRs to reduce the risk of bleeding, may prevent unnecessary suspension of anticoagulation for certain benign procedures, and encourage use of perioperative heparin, where appropriate. References 1). Blacker DJ, Wijdicks EFM, McClelland RL. Stroke risk in anticoagulated patients with atrial fibrillation undergoing endoscopy. Neurology 2003; 61: 964-968. 2). Stroke Prevention in Atrial Fibrillation Investigators. Stroke prevention in atrial fibrillation study. Final results. Circulation 1991; 84: 527-539. 3). Stroke Prevention in Atrial Fibrillation Investigators. Adjusted-dose warfarin versus low-intensity, fixed-dose warfarin plus aspirin for high- risk patients with atrial fibrillation: Stroke prevention in atrial fibrillation 111 randomised clinical trial. Lancet 1996; 348: 633-638. 4). Petersen P, Boysen G, Godtfredsen J, Andersen E, Andersen B. Placebo -controlled, randomised trial of warfarin and aspirin for prevention of thromboembolic complications in chronic atrial fibrillation. The Copenhagen AFASAK Study. Lancet 1989; 1: 175-179. 5). Connolly SJ, Laupacis A, Gent M, Roberts RS, Cairns JA, Joyner C. Canadian atrial fibrillation anticoagulation (CAFA) study. J Am Coll Cardiol 1991; 18: 349-355.