- Email: [email protected]
Prevalence of atrial septal abnormalities in older patients with cryptogenic ischemic stroke or transient ischemic attack
Letters to the Editor / Clinical Neurology and Neurosurgery 111 (2009) 562–564
References [1] The National Institute of Neurological Disorders and Stroke rt-PA Stroke Study Group. Tissue plasminogen activator for acute ischemic stroke. N Engl J Med 1995; 333:1581–87. [2] Rubinshtein R, Jaffe R, Flugelman MY, Karkabi B, Lewis BS. Thrombolysis in patients with a brain tumour. Heart 2004;90:1476. [3] Jaffe R, Reichman JM, Weiss AT, Zahger D. Thrombolysis in the presence of an intracranial meningioma. Chest 1997;111:258. [4] Sakai K, Ochiai H, Katayama N, Nakamura K, Arataki K, Kido T, et al. Catheter interventional therapy in an elderly patient with deep vein thrombosis and a brain tumor. Jpn Heart J 2004;45:709–13. [5] Actilyse. European Agency for the Evaluation of Medicinal products. Available at: http://emc.medicines.org.uk/emc/assets/c/html/displaydoc.asp?documentid= 308, Accessed 10 November 2008. [6] Bosnjak R, Derham C, Popovic´ M, Ravnik J. Spontaneous intracranial meningioma bleeding: clinicopathological features and outcome. J Neurosurg 2005;103: 473–84.
Han-Chieh Hsieh Department of Neurology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan Chih-Hung Chen a,b,∗ Department of Neurology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan b Stroke Center, College of Medicine, National Cheng Kung University, Tainan, Taiwan a
∗ Corresponding author at: Department of Neurology, College of Medicine, National Cheng Kung University, No. 1 University Road, Tainan 701, Taiwan. Tel.: +886 6 2766187; fax: +886 6 2374285. E-mail address: [email protected] (C.-H. Chen)
Available online 6 February 2009 doi:10.1016/j.clineuro.2009.01.004
Prevalence of atrial septal abnormalities in older patients with cryptogenic ischemic stroke or transient ischemic attack
a r t i c l e
i n f o
Keywords: Patent foramen ovale Transcranial Doppler Transeophageal echocardiography
563
adversely affect the accurate estimation of ‘functional potential’ of the PFO. Second, air bubbles being lighter have a tendency to move up due to buoyancy. TEE is usually performed with the patient lying in left lateral body position. This position provides an adverse environment for air microbubbles in the ‘air–saline contrast mixture’ as they have to travel from right atrium (higher position) into the left atrium (lower position)—thus defying the basic principles of physics! Mere detection of PFO in patients with cryptogenic stroke may not delineate its true etiological potential and there is a need to establish ‘functional potential’ of the PFO. Since cerebral embolization is considered to cause the ischemic cerebral event, demonstration of these paradoxical emboli in the intracranial arteries is important. Transcranial Doppler (TCD) has proven to be a reliable technique and reported to be more sensitive and specific than TEE for PFO detection [3] as well quantification of its ‘functional potential’ [4]. Power M-mode (PMD), owing to its overlapping and contiguous multiple gates may further enhance the sensitivity of TCD [5]. Body position of the patient during diagnostic testing for PFO needs special mention. As mentioned above, the traditional left lateral position during TEE is physiologically unreasonable for the travel path of ‘lighter’ microemboli. Alternatively, TCD can be performed in any anatomic position. We have demonstrated that multiple injections of the air–saline contrast mixture in various body positions are well tolerated [6]. More importantly, we established that ‘functional grading’ of the right-to-left shunt varies with body positions, larger number of microbubbles being detected in the sitting position. Furthermore, patients’ ability of performing an effective valsalva maneuver is not impaired during TCD. We believe that in addition to its morphology, ‘functional potential’ of the PFO also plays an important etiological role. ‘Low grade’ shunts may not have the same clinical relevance as the ‘large grade’ PFO. Accordingly, for establishing the etiopathogenic role of PFO, its ‘functional grading’ should always be performed in patients with cryptogenic stroke. We suggest that patients with cryptogenic strokes may be screened for the presence of a right-to-left shunt by TCD. TCD-positive patients, especially with higher ‘functional grade’ shunts should then be subjected to TEE for establishing the presence of a PFO as well as ASA. This approach would help in delineating the true relationship between atrial septal abnormalities and cryptogenic stroke as well as planning a definitive treatment.
Sir,
References
We read with great interest the study by Force et al. [1] regarding the prevalence of atrial septal abnormalities among older patients presenting with cryptogenic ischemic stroke or transient ischemic attack (TIA). Their relationship remains unclear with regards to the recommendations for management [2] and certain important issues need to be addressed. Various epidemiological studies have reported an increased incidence of patent foramen ovale (PFO), atrial septal aneurysm (ASA) or a combination of PFO and ASA in cryptogenic stroke patients as compared to the general population. Trans-esophageal echocardiography (TEE) was employed to diagnose the atrial septal abnormalities in the present study [1]. TEE is considered as goldstandard for the diagnosis of ASA as well as PFO. While ASA is best visualized during TEE, there are some important issues associated related to the diagnosis of PFO. First, although TEE can help the echocardiographer to visualize PFO and estimate its size, it is poorly tolerated by the patients. Furthermore, sedation during the procedure limits patients’ ability for performing adequate valsalva maneuver. These limitations
[1] Force M, Massabuau P, Larrue V. Prevalence of atrial septal abnormalities in older patients with cryptogenic ischemic stroke or transient ischemic attack. Clin Neurol Neurosurg 2008;110:779–83. [2] Dalen JE. Are patients with a patent foramen ovale at increased risk of stroke? A billion dollar question. Am J Med 2007;120:472–4. [3] Jauss M, Kaps M, Keberle M, Haberbosch W, Dorndorf W. A comparison of transesophageal echocardiography and transcranial Doppler sonography with contrast medium in the detection of patent foramen ovale. Stroke 1994;25:1265–7. [4] Belvis R, Leta RG, Marti-Fabregas J, Cocho D, Carreras F, Pons-Llado G, et al. Almost perfect concordance between simultaneous transcranial Doppler and transesophageal echocardiography in the quantification of right-to-left shunts. J Neuroimaging 2006;16:133–8. [5] Moehring MA, Spencer MP. Power M-mode Doppler (PMD) for observing cerebral blood flow and tracking emboli. Ultrasound Med Biol 2002;28:49–57. [6] Lao AY, Sharma VK, Tsivgoulis G, Malkoff MD, Alexandrov AV, Frey JL. Effect of body positioning during transcranial Doppler detection of right-to-left shunts. Eur J Neurol 2007;14:1035–9.
Vijay K. Sharma ∗ Hock L. Teoh Bernard P.L. Chan Division of Neurology, National University Hospital, Singapore
564
Letters to the Editor / Clinical Neurology and Neurosurgery 111 (2009) 562–564 ∗ Corresponding
author at: Division of Neurology, Department of Medicine, National University Hospital, Singapore 119074, Singapore.
Tel.: +65 67722597; fax: +65 68723566. E-mail address: [email protected] (V.K. Sharma) 27 July 2008 Available online 23 February 2009 doi:10.1016/j.clineuro.2009.01.010
References [1] The National Institute of Neurological Disorders and Stroke rt-PA Stroke Study Group. Tissue plasminogen activator for acute ischemic stroke. N Engl J Med 1995; 333:1581–87. [2] Rubinshtein R, Jaffe R, Flugelman MY, Karkabi B, Lewis BS. Thrombolysis in patients with a brain tumour. Heart 2004;90:1476. [3] Jaffe R, Reichman JM, Weiss AT, Zahger D. Thrombolysis in the presence of an intracranial meningioma. Chest 1997;111:258. [4] Sakai K, Ochiai H, Katayama N, Nakamura K, Arataki K, Kido T, et al. Catheter interventional therapy in an elderly patient with deep vein thrombosis and a brain tumor. Jpn Heart J 2004;45:709–13. [5] Actilyse. European Agency for the Evaluation of Medicinal products. Available at: http://emc.medicines.org.uk/emc/assets/c/html/displaydoc.asp?documentid= 308, Accessed 10 November 2008. [6] Bosnjak R, Derham C, Popovic´ M, Ravnik J. Spontaneous intracranial meningioma bleeding: clinicopathological features and outcome. J Neurosurg 2005;103: 473–84.
Han-Chieh Hsieh Department of Neurology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan Chih-Hung Chen a,b,∗ Department of Neurology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan b Stroke Center, College of Medicine, National Cheng Kung University, Tainan, Taiwan a
∗ Corresponding author at: Department of Neurology, College of Medicine, National Cheng Kung University, No. 1 University Road, Tainan 701, Taiwan. Tel.: +886 6 2766187; fax: +886 6 2374285. E-mail address: [email protected] (C.-H. Chen)
Available online 6 February 2009 doi:10.1016/j.clineuro.2009.01.004
Prevalence of atrial septal abnormalities in older patients with cryptogenic ischemic stroke or transient ischemic attack
a r t i c l e
i n f o
Keywords: Patent foramen ovale Transcranial Doppler Transeophageal echocardiography
563
adversely affect the accurate estimation of ‘functional potential’ of the PFO. Second, air bubbles being lighter have a tendency to move up due to buoyancy. TEE is usually performed with the patient lying in left lateral body position. This position provides an adverse environment for air microbubbles in the ‘air–saline contrast mixture’ as they have to travel from right atrium (higher position) into the left atrium (lower position)—thus defying the basic principles of physics! Mere detection of PFO in patients with cryptogenic stroke may not delineate its true etiological potential and there is a need to establish ‘functional potential’ of the PFO. Since cerebral embolization is considered to cause the ischemic cerebral event, demonstration of these paradoxical emboli in the intracranial arteries is important. Transcranial Doppler (TCD) has proven to be a reliable technique and reported to be more sensitive and specific than TEE for PFO detection [3] as well quantification of its ‘functional potential’ [4]. Power M-mode (PMD), owing to its overlapping and contiguous multiple gates may further enhance the sensitivity of TCD [5]. Body position of the patient during diagnostic testing for PFO needs special mention. As mentioned above, the traditional left lateral position during TEE is physiologically unreasonable for the travel path of ‘lighter’ microemboli. Alternatively, TCD can be performed in any anatomic position. We have demonstrated that multiple injections of the air–saline contrast mixture in various body positions are well tolerated [6]. More importantly, we established that ‘functional grading’ of the right-to-left shunt varies with body positions, larger number of microbubbles being detected in the sitting position. Furthermore, patients’ ability of performing an effective valsalva maneuver is not impaired during TCD. We believe that in addition to its morphology, ‘functional potential’ of the PFO also plays an important etiological role. ‘Low grade’ shunts may not have the same clinical relevance as the ‘large grade’ PFO. Accordingly, for establishing the etiopathogenic role of PFO, its ‘functional grading’ should always be performed in patients with cryptogenic stroke. We suggest that patients with cryptogenic strokes may be screened for the presence of a right-to-left shunt by TCD. TCD-positive patients, especially with higher ‘functional grade’ shunts should then be subjected to TEE for establishing the presence of a PFO as well as ASA. This approach would help in delineating the true relationship between atrial septal abnormalities and cryptogenic stroke as well as planning a definitive treatment.
Sir,
References
We read with great interest the study by Force et al. [1] regarding the prevalence of atrial septal abnormalities among older patients presenting with cryptogenic ischemic stroke or transient ischemic attack (TIA). Their relationship remains unclear with regards to the recommendations for management [2] and certain important issues need to be addressed. Various epidemiological studies have reported an increased incidence of patent foramen ovale (PFO), atrial septal aneurysm (ASA) or a combination of PFO and ASA in cryptogenic stroke patients as compared to the general population. Trans-esophageal echocardiography (TEE) was employed to diagnose the atrial septal abnormalities in the present study [1]. TEE is considered as goldstandard for the diagnosis of ASA as well as PFO. While ASA is best visualized during TEE, there are some important issues associated related to the diagnosis of PFO. First, although TEE can help the echocardiographer to visualize PFO and estimate its size, it is poorly tolerated by the patients. Furthermore, sedation during the procedure limits patients’ ability for performing adequate valsalva maneuver. These limitations
[1] Force M, Massabuau P, Larrue V. Prevalence of atrial septal abnormalities in older patients with cryptogenic ischemic stroke or transient ischemic attack. Clin Neurol Neurosurg 2008;110:779–83. [2] Dalen JE. Are patients with a patent foramen ovale at increased risk of stroke? A billion dollar question. Am J Med 2007;120:472–4. [3] Jauss M, Kaps M, Keberle M, Haberbosch W, Dorndorf W. A comparison of transesophageal echocardiography and transcranial Doppler sonography with contrast medium in the detection of patent foramen ovale. Stroke 1994;25:1265–7. [4] Belvis R, Leta RG, Marti-Fabregas J, Cocho D, Carreras F, Pons-Llado G, et al. Almost perfect concordance between simultaneous transcranial Doppler and transesophageal echocardiography in the quantification of right-to-left shunts. J Neuroimaging 2006;16:133–8. [5] Moehring MA, Spencer MP. Power M-mode Doppler (PMD) for observing cerebral blood flow and tracking emboli. Ultrasound Med Biol 2002;28:49–57. [6] Lao AY, Sharma VK, Tsivgoulis G, Malkoff MD, Alexandrov AV, Frey JL. Effect of body positioning during transcranial Doppler detection of right-to-left shunts. Eur J Neurol 2007;14:1035–9.
Vijay K. Sharma ∗ Hock L. Teoh Bernard P.L. Chan Division of Neurology, National University Hospital, Singapore
564
Letters to the Editor / Clinical Neurology and Neurosurgery 111 (2009) 562–564 ∗ Corresponding
author at: Division of Neurology, Department of Medicine, National University Hospital, Singapore 119074, Singapore.
Tel.: +65 67722597; fax: +65 68723566. E-mail address: [email protected] (V.K. Sharma) 27 July 2008 Available online 23 February 2009 doi:10.1016/j.clineuro.2009.01.010