engleski

CORRELATION OF NEUROLOGICAL SYMPTOMS AND BHI VALUES IN PATIENTS WITH SEVERE INTERNAL CAROTID STENOSIS

Background: The aim of the study is to evaluate the role of measuring cerebral vasoreactivity in follow up of patients with severe internal carotid stenosis. We used breath holding index (BHI) as a quantitative parameter of cerebral vasoreactivity and functional state of cerebral hemodynamics. Methods: We evaluated data from 150 patients with high grade carotid stenosis (definition according to standardized criteria of Cerebrovascular laboratory-Referral Center for Neurovascular Disorders Ministry of Health Republic of Croatia). All patients underwent CDFI, TCD and CT/MR imaging tests, complete laboratory workup, ECG, chest X-ray and spinal tap in selected cases. CDFI and TCD findings were done in standardized manner. Breath holding index was calculated as percentage increase in MBFV occurring during breath holding divided by the time (seconds) for which the subject hold his/her breath. All patients had verified recent ischemia of brain parenchyma on CT/MR scan. Results: There were 29 (19%) symptoms free patients-14 (9%) men and 15 (9%) women who had BHI higher than 0, 7 (65% of them activated anterior collateral pathway-BHI=0, 95&#177; 0, 6 ; 27% activated posterior collateral pathway-BHI=0, 83&#177; 0, 4 and 6% activated 2 or more collateral pathways-BHI=0, 78&#177; 0, 1. There were 35 (23%) of patients-15 (9%) men and 20 (13%) women with transient neurological symptoms, CT/MR scan was without recent ischemic lesions- BHI wasł0, 7 ; they mostly activated anterior collateral pathway- 30 (87%) patients ; or anterior collateral pathway in addition with ophthalmic artery collateral pathway or posterior collateral pathway-5 patients (13%). There were 86 (58%) patients with verified recent ischemia of brain parenchyma-54 (36%) men and 32 (21%) women- BHI<0, 7 ; they mostly activated two collateral pathways-54 (63%) patients- BHI=0, 52&#177; 0, 12 ; only 18 (21%) patients activated only one (anterior) collateral pathway- BHI=0, 35&#177; 0, 10, 14 (16%) patients activated 3 or more collateral pathways-mostly anterior, posterior and ophthalmic collateral pathway together- BHI=0, 27&#177; 0, 11. There were 38 (45%) patients with first ever stroke-17 (32%) men and 21 (66%) women, they mostly activated one collateral pathway (33 patients-87%)-anterior or posterior one ; BHI=0, 41&#177; 0, 12, while patients with recurrent stroke-48 (55%) patients ; 37(68%) men and 11 (34%) women activated two or more collateral pathways (44 patients-91%)-anterior and posterior collateral pathway in addition with ophthalmic artery collateral pathway or cortical collaterals ; BHI=0, 13&#177; 0, 16. There were 54% of symptomatic patients who had amaurosis fugax (in strong correlation with activation of ophthalmic artery collateral pathway), 23% of patients had non-specific symptoms like dizziness, headache or vomiting, 77% of patients had hemispheric symptoms according to the site of stenosis (BHI<0, 7). Conclusion: Breath holding index is easy and reproducible, real time method in follow up of patients with severe carotid disease. It is very useful in predicting decompensation of intracranial collateral circulation, hemodynamic insufficiency and cerebrovascular incident.

breath holding Index; transcranial doppler; carotid stenosis

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