Original Contribution

antithrombotic therapy for prevention of stroke in clinical practice in the ED

Asia Kogan MD^a,*, Reuma Shapira MD^a, Ada Tamir DSc^b, Gad Rennert MD, PhD^b

^aEmergency Department, Carmel Medical Center, Haifa 34362, Israel

^bCommunity Medicine and Epidemiology Department, Carmel Medical Center, Haifa 34362, Israel

Received 6 February 2006; revised 20 March 2006; accepted 20 March 2006

Abstract

Objective: The objective of this study was to analyze the emergency medicine department’s practice of recommending anticoagulation medication for Stroke prevention, its compliance with clinical guidelines, and the role of the emergency physician in recommending anticoagulation medication. We also determined the occurrence of Thromboembolic events in patients with Atrial fibrillation during a follow-up period of up to 8 months after their discharge from the ED.

Materials and Methods: Over a 6-month period, patients presenting to the ED with AF were registered using a predesigned 2-part questionnaire. The first part considered the management of the patients with AF at the ED; the second part evaluated data on patients who returned to the ED and their treatment follow-up, based on the drug supply registry.

Results: This study included 102 ED visits by patients with AF, of whom 38 were hospitalized and

64 were discharged. Thirty-six of the discharged patients required anticoagulation according to American College of Cardiology/American Heart Association Task Force on Practice Guidelines/ European Society of Cardiology guidelines. Of these patients, 28 (78%) were recommended anticoagulation medication and 8 (25%) were not: 5 because of contraindications and 3 because of unknown reasons. No patient returned to the ED with a thromboembolic event during the 8-month follow-up period.

Conclusion: The prevalence of anticoagulation recommendation for stroke prevention and compliance with clinical guidelines were found to be greater than previously reported. Our data show that most of the patients with AF and risk factors for stroke were recommended anticoagulation medication. This study illustrates the importance of applying clinical guidelines in daily practice and integrating them into patients’ medical files in the ED.

D 2007

Introduction

Atrial fibrillation is a growing Public health problem associated with significant morbidity and mor- tality [1].

* Corresponding author.

During the last decades, AF has become the most frequent arrhythmia seen in the ED and the cause of more hospital admissions than any other rhythm disturbance. Along with these developments, a profound change has taken place in the treatment of patients with AF [2,3].

A change has also been seen in patients’ behavior: increasing numbers of patients tend to abandon convention- al health care facilities and go directly to the ED.

0735-6757/$ - see front matter D 2007 doi:10.1016/j.ajem.2006.03.024

Randomized controlled trials with warfarin have conclu- sively demonstrated that long-term anticoagulation therapy can reduce the risk of stroke by approximately 68% per year in patients with valvular heart disease and AF as well as in patients without valvular disease [4-7]. Despite these conclusive evidence of the medication’s efficacy, several studies have shown suboptimal use of warfarin worldwide: it is recommended for only 15% to 44% of patients with AF who have no contraindication [2,8].

Initial therapy of AF in the ED is often directed toward achieving Rate control as well as obtaining and maintaining sinus rhythm, in addition to the goal of reaching an International normalized ratio of anticoagulation between 2 and 3. Anticoagulation should be continued indefinitely in groups of high-risk patients with AF (according to American College of Cardiology/American Heart Association Task Force on Practice Guidelines/ European Society of Cardiology [ACC/AHA/ESC] recom- mendations from 2001 [9]) because most strokes occur in patients who discontinued their anticoagulant medication, those whose INR was subtherapeutic, or those without anticoagulant therapy [5,6,9].

The importance of providing therapy protocols for practicing physicians in the ED is undisputed, and such a protocol is particularly significant in the treatment of patients with AF. This study implemented the protocol’s guidelines not only within the boundaries of the ED but also in cooperation with the cardiology and internal medicine departments in the hospital as well as with outpatient clinics in the community.

Materials and methods

The Carmel Medical Center has approximately 500 beds (including cardiac care units) and serves a population of 200000 people. Its ED has approximately 80 000 visits a year. Patients who presented to our ED with AF between December 2004 and May 2005 were registered and included

in this study.

Data regarding each patient were provided by the treating ED physician using a 2-part questionnaire. Part 1, which was filled prospectively, included demographic variables, medical history, details regarding AF duration (less or more than 48 hours), symptoms, risk factors for thromboembo- lism (TE), INR in the ED, treatment before entering the ED and in the ED (including antiarrhythmic treatments, rate control, antiaggregants, and anticoagulants), medical or electric cardioversion, complications, admission diagnosis, and recommendations upon discharge. We evaluated rea- sons for not recommending anticoagulation medication to patients for whom it was indicated according to ACC/AHA/ ESC guidelines [9]. At a later stage, this part was used routinely in our ED patients’ files.

Part 2 of the questionnaire, which was filled retrospec- tively, included patients from the first part who returned to

the ED up until August 2005 and their diagnosis upon returning. The data were obtained from OFEK (DB Motion, Omer, Israel), a designated patient information management system. This system includes hospitalization records of all hospitals in Israel. Because there is no private internal medicine hospital in Israel, this system enabled us to electronically follow all participants in all the area hospitals. All medical decisions in the ED were made according to guidelines developed in our hospital as a cooperative project of the ED with the internal medicine and cardiology departments in accordance with ACC/AHA/ESC guidelines. In this part, we also evaluated adherence to anticoagu-

lation by referring to the drug supply registry.

All discharged patients who were recommended anti- coagulation (also those continuing anticoagulation) were given a guidance paper explaining anticoagulation-the drugs, the correct way to use them, their side effects and risks, and the way to maintain a therapeutic level-in the

3 most common languages in Israel (Hebrew, Arabic, Russian). They were also given a discharge letter to inform their primary physician of the need to provide anticoagu- lation medication and follow and control INR.

Results

During the study period (between December 2004 and May 2005), 102 ED visits by patients with AF were recorded; 38 of these patients were hospitalized and 64 were discharged.

Baseline characteristics are listed in Table 1. There were 50 men and 52 women in the study; 20 patients (19.6%)

were younger than 65 years, 33 (32.4%) were between

65 and 75 years old, and 49 (48%) were older than 75 years. The most common complaints upon arrival at the ED were palpitations (55%), dyspnea (32.8%), and chest pain (19.6%), whereas 21.6% of patients had complaints

unrelated to AF.

Duration of AF was less than 48 hours upon arrival at the ED in 26.5% of the patients, more than 48 hours in 38.2%, and unknown in 35.3%.

The clinical characteristics of the 64 patients discharged from the ED are listed in Table 2. Among the discharged patients, 55 (86%) had risk factors for TE, the most common of which was hypertension (77.5%), then coronary heart disease (36.4%), heart surgery (23.6%), congestive heart failure (20%), valvular heart disease (16.7%), cardiomegaly (3.6%), thromboembolic event in the past (3.6%), and diabetes mellitus (1.8%).

Thirty-six (56%) of the discharged patients with risk factors for TE had not received anticoagulation medication before. Twenty-eight of these patients were discharged with a first-time recommendation for anticoagulation medication, as were 2 additional patients who demonstrated no risk factor. At the 6-month follow-up, 19 of the patients for whom anticoagulation medication was recommended were

Male	50 (49)
Female	52 (51)
Age (y)
b65	20 (19.6)
65-75	33 (32.4)
N75 Complaint upon arrival	49 (48)
Palpitation	57 (56.8)
Dyspnea	34 (33.8)
Chest pain	20 (19.8)
Unrelated to AF	23 (22.8)
AF duration (h)
N48	39 (38.8)
b48	27 (26.8)
Unknown	36 (35.8)

Rate control	69 (68.8)
Medical cardioversion	29 (28.8)
Electric cardioversion	2 (2)
Anticoagulants	65 (64.8)
Sinus rhythm achieved	39 (38.8)

still adhering to their therapeutic anticoagulant regimen, 6 had ceased taking the anticoagulation medication, and no information was found regarding 5 others.

Table 1 Clinical and demographic characteristics of the

patients (N = 102)

Variables n (%)

Discharged

Indications for admission Ischemic heart disease Arrhythmia

TE

Congestive heart failure Syncope

Syncope + ischemic heart disease Syncope + Arrhythmia

Other

Coumadin treatment INR

b2

2-3.5

N3.5

Treatment in the ED

64 (63.8)

6

10

1

7

1

1

1

11

38 (37.8)

11 (27.8)

13 (35.6)

14 (36.8)

Nineteen of the discharged patients were hospitalized during a mean follow-up period of 6 months; none of these hospitalizations was caused by a thromboembolic event (10 for cardiac disease, 3 for pulmonary disease, and 6 for

other reasons).

Eight (22%) of the discharged patients with risk factors for TE were not recommended anticoagulation medication: 2 because of bleeding history, 5 were not compatible with anticoagulation (dementia, recurrent falls), and 3 for unknown reasons. Nine of the discharged patients did not have risk factors for TE, but 3 of them received a recommendation for anticoagulation medication nonetheless (1 had already taken coumadin before). Twenty of the discharged patients had been taking anticoagulation medi-

cation before their ED visit, and it was recommended that they continue the regimen.

Of the 55 patients with risk factors, 23 (41.8%) had 1 risk factor, 12 (21.8%) had 2 risk factors, and 20 (36.4%) had 3 or more risk factors.

Among the 38 (37.3%) patients who had been treated with anticoagulation before their ED visit, the INR was lower than 2 (nontherapeutic) in 27.8% and greater than

3.5 (overtherapeutic) in 36.6%; adequate coagulation measures were found in only 35.6%.

In the ED, 68.6% received rate control, 28.7% did medical cardioversion, 2.0% did electric cardioversion, and 64.7% did anticoagulants (warfarin and/or enoxaparin). Thirty-five of the patients returned to sinus rhythm in the ED (38.6%), 2 of them after electric cardioversion.

indications for hospitalization (38 patients) were arrhyth- mias in 10 patients, TE in 1 patient, congestive heart failure in 7 patients, syncope in 1 patient, ischemic heart disease in

6 patients, combination of ischemic heart disease and syncope in 1 patient, syncope and arrhythmia in 1 patient, and other reasons in 11 patients.

Sixty percent of the discharged patients were recom- mended a change in their medication regimen, including the addition of anticoagulation and/or rate control and/or antiaggregants.

Discussion

Atrial fibrillation is the most frequent arrhythmia seen in the ED [10] and a very common reason for hospitalization [11,12]. Patients with AF compose a heterogenic group

Table 2 Clinical characteristics of the discharged patients (n= 64)

Variable n (%)

Risk factors for TE 55 (86)

Hypertension	43 (77.5)
Ischemic heart disease	20 (36.4)
Heart surgery	13 (23.6)
Congestive heart failure	11 (20)
Cardiomegaly	2 (3.6)
TE in the past	2 (3.6)
Diabetes mellitus	1 (1.8)
1 risk factor	23 (41.8)
2 risk factors	12 (21.8)
z3 risk factors	20 (36.4)
anticoagulant treatment before	20 (31.2)
No anticoagulation before	44 (68.8)
Anticoagulation recommendation total	49 (76.5)
New anticoagulation recommendation	28 (77.7)
No recommendation despite risk factors	8 (22)
Reasons for no recommendation
Bleeding	2
Not compatible with treatment	5
Unknown	3

regarding etiology, natural course, therapeutic approach, and complications-mostly thromboembolic (stroke). Because AF is not always symptomatic, we found that 22% of our patients arrived at the ED for other complaints, and AF was found coincidentally and treated according to our guidelines.

The prevalence of AF starts to increase after age 40 years and rises rapidly after age 65 years, reaching a prevalence of approximately 10% in patients older than 80 years. This finding is in accordance with our finding that more than 80% of the study patients were older than 65 years. Along with the increasing prevalence of AF, the rate of ischemic stroke in patients with AF increases from 1.5% between the ages of 50 and 59 years to 23.5% between the ages of 80 and 89 years [3].

Risk factors, such as congestive heart failure, hyperten- sion, cardiac disorders, diabetes, and previous embolism, pose an increased risk for thromboembolic events in patients with AF [1,2,9]. The risk increases if more than 1 risk factor are found. In our study, more than 58% of the patients had more than 3 risk factors, placing them at greater risk for TE if not properly treated.

The ED population represents a wide spectrum of patients with AF and other risk factors, many of whom are not hospitalized [10,13]. Finding that more than 67% of our patients with AF were discharged led us to examine the therapeutic approach to patients with AF in general and the recommendation of antithrombotic therapy for these patients in particular, with a special focus on the patients with AF who were discharged from the ED and needed to receive the correct recommendations upon discharge. Although the literature reports that only 15% to 44% of patients with AF who need antithrombotic therapy get a recommendation for it upon discharge from the ED [8,14,15], we found that antithrombotic (anticoagulant) treatment was recommended to 78% of our discharged patients.

The rate of ischemic stroke per year in patients with AF is 2 to 7 times greater than the 5% rate reported in nonrheumatic patients [16,17]. Most thromboembolic events in this patient group occurred in patients who stopped their anticoagulation therapy or had subtherapeutic INR.

Although a high percentage (36.3%) of our study population had been receiving anticoagulation therapy before their arrival, only 47% of them were well within the optimal INR range (29% had overcoagulation and 24% had undercoagulation). This demonstrated the need of patients- those already receiving anticoagulation therapy and those starting this therapeutic regimen for the first time- for proper guidance regarding the administration of anticoagu- lation therapy. To this end, we devised a guidance paper for patients, as mentioned in the Materials and Methods section. The incidence of bleeding among patients receiving Oral anticoagulation therapy is between 0.5% and 1%; of these cases, 10% require treatment [12,13]. In the current study, not even one case of bleeding was recorded during the

follow-up period.

Before this project, we had completed a joint quality project with the cardiology and internal medicine depart- ments for patients with AF that helped finalize the guide- lines for ED physicians treating patients with AF. In the current project, we evaluated the application of these guidelines in the ED, which were used in conjunction with ACC/AHA/ESC guidelines.

We found that the guidelines were applied in the cases of more than 75% of the discharged patients by recommending anticoagulation prophylaxis in the setting of the ED. They were also applied at the scene of the ED in more than 65% of the patients when trying to convert the rhythm to sinus rate. These guidelines were also implemented at our outpatient clinics in general and in the cardiology clinics in particular by maintaining closer contact with them regarding changes in medication and rhythm during follow-up. All of these steps, the guidelines for treating physicians, the guidance papers for patients, and the dissemination of both to clinics within the community, led to greater than 60% Patient adherence to the recommended anticoagulation medication regimen and consequently to no thromboembolic event in the discharged patients during the follow-up period. We ascribe this high rate of adherence to the steps described, to the discharging physician’s ability to provide clear instruc- tions to the patient regarding medication administration, and to the cooperation of the outpatient clinics. Undoubtedly, guidelines for clinical practice improve the outcome of

health care.

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