Risk factors for cerebrovascular events: end-diastolic flow velocity

There are very few studies analysing blood flow velocity parameters of common carotid arteries (CCA), obtained with color Doppler examination as a predictor in cerebrovascular events (CVE). In everyday clinical practice there are number of patients (pts) without carotid stenosis or occlusion but with decreased blood flow velocities.

We performed this study to compare data of velocity parameters with type of cerebrovascular events (CVE) and multiple risk factors in patients without stenotic or occlusive extracranial disease.

We included total of 127 consecutive patients who experienced various subtypes of cerebrovascular events, 68 females, 59 males, mean age 70.2 +/- SD 12.4 years, out of them 48 pts. had transients ischemic attacs (TIAs), 31 pts. had recurrent TIAs (recTIAs), 32 pts. developed ischemic stroke (IS), and 16 recurrent IS (recIS). All patients were without hemodynamically significant carotid stenosis or occlusion. As a control group we took 50 patients with comparable mean age and gender distribution, all without cerebrovascular events, but with at least 1 multiple risk factor. We included the following clinical variables: age, gender, hypertension, tobacco smoking, hyperlipidemia, obesity, diabetes mellitus. Velocity parameters were: peak-systolic velocity (PSV), end-diastolic velocity (EDV), pulsatility index (PI), resistive index (RI). Examination was performed on distal portion of CCA, and we took the mean of both CCA.

Hemodynamic parameters in CVE pts were: PSV 83.5 cm/sec, EDV 19.5 cm/sec, PI 1.54, and RI 0.77, and in Controls values were: PSV 87.5 cm/sec, EDV 28.5 cm/sec, PI 1.42, RI 0.67, respectively. No sign. diff. in PSV and PI were found between CVE (n=127) and Controls (n=50), p = 0.2, while difference in EDV was significant, p < 0.01. We found significance for the following variables: age, tobacco smoking, hypertension, hyperlipidemia and obesity. The best single predictors for CVE were: age (70.1%, p < 0.01), tobacco smoking (63%, p < 0.01, hypertension (52.8%, p < 0.01) and obesity (51.2%, p < 0.01). and among hemodynamic parameters, end-diastolic velocity less than 18 cm/sec (p < 0.05). Decreased EDV (below 18 cm/sec) revealed a significant association with CVE.

(a) we found significantly lower EDV in pts with IS and recIS, (b) EDV below 18 cm/sec was the best single predictor of IS, and recIS, (c) in our CVE pts--age, tobacco smoking, hypertension, obesity, were the best single predictors for CVE.