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By Kateriine Orav, Department of Neurology, North Estonia Medical Center, Tallinn, Estonia

The use of echocardiography in stroke workup varies considerably between stroke centres. A global survey conducted in 2015 showed that in 301 stroke centres across the world transthoracic echocardiography (TTE) was used routinely (≥75% of cases) in 70% of cryptogenic stroke patients and transoesophageal echocardiography (TEE) was used routinely in 17% of patients.1 Recommendations about the use of echocardiography in stroke patients have been somewhat vague. The recent AHA/ASA Prevention of Stroke Guideline stated that echocardiography in patients with cryptogenic stroke and TEE in patients with embolic stroke of undetermined source is reasonable.2  However, uncertainties remain about which patients require echocardiography and which mode of echocardiography should be preferred.

TEE is considered more sensitive for the detection of major cardiac sources of emboli such as left atrial thrombus, aortic atheroma, valve abnormalities, atrial septal abnormalities and cardiac tumours. TTE is more suited for the visualization of left ventricular thrombus.3 In a recently published prospective multicentre cohort study by Thomalla et al. TEE showed a significantly higher rate of treatment relevant findings in cryptogenic stroke patients than TTE (18.9% vs 14.1%). Patients ≤60 years old benefitted more from TEE with a number needed to diagnose of 7 compared to 16 in all age groups.  Adding TEE to TTE resulted in an absolute increase of treatment-relevant findings by 6.4%.4  Previous studies have also shown TEE to be superior for the identification of a cardiac embolic source, changing the treatment strategy in 16-30% of patients. 5,6,7

While we have strong recommendations for the management of some high embolic potential cardiac sources like atrial fibrillation, we have little evidence about management of some others such as aortic atheroma. With more evidence for these scenarios the importance of such findings will likely increase in the future. Echocardiographic findings may also aid in the classification of strokes and this may carry indirect benefits such as recommending more aggressive treatment of vascular risk factors in large artery atherosclerosis or further cardiac examinations in cases considered cardioembolic.4

TTE is often considered as a screening instrument for cardiac structural abnormalities, but some patient may benefit more from TEE. While TEE has been commonly used in younger patients to detect atrial septal defects, it has shown to be valuable also in older patients in determining stroke aetiology and influencing secondary prevention strategies.8  As TEE is semi-invasive, more expensive and often more difficult to access, future research on this topic will be crucial to understand which patients will be likely to benefit from TEE in their stroke workup.

References

  1. Giruparajah M, Bosch J, Vanassche T, et al. Global survey of the diagnostic evaluation and management of cryptogenic ischemic stroke. Int J Stroke. 2015 Oct;10(7):1031-6.
  2. Kleindorfer DO, Towfighi A, Chaturvedi S, et al. 2021 Guideline for the Prevention of Stroke in Patients With Stroke and Transient Ischemic Attack: A Guideline From the American Heart Association/American Stroke Association. 2021 Jul;52(7):e364-e467.
  3. Saric M, Armour AC, Arnaout MS, et al. Guidelines for the Use of Echocardiography in the Evaluation of a Cardiac Source of Embolism. J Am Soc Echocardiogr. 2016 Jan;29(1):1-42.
  4. Thomalla G, Upneja M, Camen S, et al. Treatment-Relevant Findings in Transesophageal Echocardiography After Stroke: A Prospective Multicenter Cohort Study. 2021 Sep 9:STROKEAHA121034868.
  5. Harloff A, Handke M, Reinhard M, et al. Therapeutic strategies after examination by transesophageal echocardiography in 503 patients with ischemic stroke. 2006 Mar;37(3):859-64.
  6. de Bruijn SF, Agema WR, Lammers GJ, et al. Transesophageal echocardiography is superior to transthoracic echocardiography in management of patients of any age with transient ischemic attack or stroke. 2006 Oct;37(10):2531-4.
  7. Katsanos AH, Bhole R, Frogoudaki A, et al. The value of transesophageal echocardiography for embolic strokes of undetermined source. 2016 Sep 6;87(10):988-95.
  8. Strecker C, Günther F, Harloff A. Who Should Rather Undergo Transesophageal Echocardiography to Determine Stroke Etiology: Young or Elderly Stroke Patients? Front Neurol. 2020 Dec 18;11:588151.