Correspondence

Transient Ischemic Attack

N Engl J Med 2003; 348:1606April 17, 2003

Article

To the Editor:

In his discussion of transient ischemic attacks (TIAs), Dr. Johnston (Nov. 21 issue)1 did not discuss the role of echocardiography. It is estimated that at least 20 percent of acute neurologic ischemic events are cardioembolic in origin.2,3 The exact incidence of cardiac causes probably varies according to age, coexisting conditions, and the type of neurologic presentation.4 For this reason, the American College of Cardiology–American Heart Association guidelines for the clinical application of echocardiography state that echocardiography is a class I indication for all patients less than 45 years of age who have neurovascular events and for patients older than 45 without other obvious causes.5

The patient described in the case vignette had a sudden interruption of blood flow in the territory of the left middle cerebral artery — a clinical scenario that probably increases the likelihood of finding a cardiac embolus. In addition to potentially identifying the cause of the TIA, echocardiography would certainly alter the management of this case if a thrombus, spontaneous echo contrast, vegetation, patent foramen ovale, myocardial aneurysm, or tumor were discovered. Thus, we believe that in selected patients, echocardiography is an integral part of the evaluation of transient ischemic attacks and deserved mention in the discussion by Dr. Johnston.

Micah J. Eimer, M.D.
Nalini M. Rajamannan, M.D.
Northwestern University, Chicago, IL 60611
m-eimer@northwestern.edu

5 References

1. 1

   Johnston SC. Transient ischemic attack. N Engl J Med 2002;347:1687-1692
   Full Text | Web of Science | Medline

2. 2

   Hofmann T, Kasper W, Meinertz T, Geibel A, Just H. Echocardiographic evaluation of patients with clinically suspected arterial emboli. Lancet 1990;336:1421-1424
   CrossRef | Web of Science | Medline

3. 3

   Pop G, Sutherland GR, Koudstaal PJ, Sit TW, de Jong G, Roelandt JR. Transesophageal echocardiography in the detection of intracardiac embolic sources in patients with transient ischemic attacks. Stroke 1990;21:560-565
   CrossRef | Web of Science | Medline

4. 4

   Zeiler K, Siostrzonek P, Lang W, et al. Different risk factor profiles in young and elderly stroke patients with special reference to cardiac disorders. J Clin Epidemiol 1992;45:1383-1389
   CrossRef | Web of Science | Medline

5. 5

   Cheitlin MD, Alpert JS, Armstrong WF, et al. ACC/AHA guidelines for the clinical application of echocardiography: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on Clinical Application of Echocardiography): developed in collaboration with the American Society of Echocardiography. Circulation 1997;95:1686-1744
   Web of Science | Medline

Author/Editor Response

As I mention in the article, echocardiography is recommended if diagnostic uncertainty persists after an initial evaluation that includes electrocardiography and head and neck imaging.1 Without knowledge of the results of the initial evaluation of the patient described in the article, it is not clear whether echocardiography would be indicated in her case.

Echocardiography is probably underused after TIA. In patients with recent stroke from no obvious cause, transesophageal echocardiography may reveal an indication for anticoagulation therapy or another intervention and appears to be cost effective.2 However, the benefits of anticoagulation therapy or other specific treatments have not been established for many “abnormal” findings on echocardiography, which may be associated with an increased risk of stroke, including spontaneous contrast and patent foramen ovale.3,4 Furthermore, if atrial fibrillation is documented, echocardiography may not alter the decision to provide anticoagulation therapy. Additional analysis of data from patients undergoing echocardiography in the Warfarin–Aspirin Recurrent Stroke Study may clarify the implications of this diagnostic approach by revealing whether patients with specific findings benefit from anticoagulation therapy.5

Limited space in the Clinical Practice article prevented a detailed discussion of some issues that are important in the management of TIA. I thank Drs. Eimer and Rajamannan for helping to clarify one of these issues.

S. Claiborne Johnston, M.D., Ph.D.
University of California, San Francisco, San Francisco, CA 94143-0114
clay.johnston@ucsfmedctr.org

5 References

1. 1

   Feinberg WM, Albers GW, Barnett HJ, et al. Guidelines for the management of transient ischemic attacks: from the Ad Hoc Committee on Guidelines for the Management of Transient Ischemic Attacks of the Stroke Council of the American Heart Association. Circulation 1994;89:2950-2965
   Web of Science | Medline

2. 2

   McNamara RL, Lima JA, Whelton PK, Powe NR. Echocardiographic identification of cardiovascular sources of emboli to guide clinical management of stroke: a cost-effectiveness analysis. Ann Intern Med 1997;127:775-787
   Web of Science | Medline

3. 3

   Homma S, Sacco RL, Di Tullio MR, Sciacca RR, Mohr JP. Effect of medical treatment in stroke patients with patent foramen ovale: Patent Foramen Ovale in Cryptogenic Stroke Study. Circulation 2002;105:2625-2631
   CrossRef | Web of Science | Medline

4. 4

   Manning WJ. Role of transesophageal echocardiography in the management of thromboembolic stroke. Am J Cardiol 1997;80:19D-28D, 35D
   CrossRef | Web of Science | Medline

5. 5

   Mohr JP, Thompson JLP, Lazar RM, et al. A comparison of warfarin and aspirin for the prevention of recurrent ischemic stroke. N Engl J Med 2001;345:1444-1451
   Full Text | Web of Science | Medline