It is a case-control observational analytical study for 200 patients recruited from Ain Shams University Hospitals. We recruited 100 patients admitted with ischemic stroke and 100 patients as control group from outpatient clinics. The active group included patients with transient ischemic attack or ischemic stroke (first ever or recurrent) following the label of large or small vessel according to Trial of ORG 10172 in Acute Stroke Treatment (TOAST) classification , where the diagnosis established clinically from the history, examination and investigatory tools in patient ≥ 45 years. Control group patients—selected from internal medicine outpatient clinic—were matched to case group in age and sex. We excluded patients with cardioembolic stroke, stroke of undetermined etiology, or patients aged under 45 years.
To determine the ABI with the Doppler method, we followed the American Heart Association recommendation statement. The patient should be at rest for 5 to 10 min in the supine position with the head and heels supported, and the room should be at a comfortable temperature. The blood pressure cuff should contour the limb circumference. Patients must remain still during the measurement. The cuff should be positioned around the ankle with the straight wrapping method, as with brachial measurement, and the lower edge should be 2 cm above the superior aspect of the medial malleolus. Using portable hand held Doppler (model Life Dop L250R with SD8 probe product by Summit Doppler, China), an 8-MHz Doppler probe with gel applied over the sensor, the device was placed in the area of the pulse at a 45° to 60° angle to the skin surface. We move the probe to find the clearest signal. To detect the pressure, the cuff is inflated progressively to 20 mmHg above the level of flow signal disappearance and then slowly deflated to detect signal reappearance. We used also Doppler to detect brachial blood flow during the arm pressure measurement. The same sequence of limb pressure measurement should be used, and the sequence was the same for all patients within our study. If the first arm measurement is 10 mmHg or greater than the other arm, then it should be repeated at the end of the sequence, and the two numbers averaged. For example, when beginning with the right arm and using the counter clockwise sequence (in the following order: right arm, right posterior tibial, right dorsalis pedis, left posterior tibial, left dorsalis pedis, left arm), the right arm measurement would be repeated, and the two measurements should be averaged. However, if the difference between the two numbers is greater than 10 mmHg, only the second measurement should be used to lessen the white coat effect. The highest systolic blood pressure in the leg was then divided by the average systolic pressure in both arms. Criteria for PAD diagnosis is an ABI of < 0.9 .
Patients’ group was assessed using magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) and magnetic resonance angiography (MRA) for intracranial circulation, transthoracic echocardiography, electrocardiography, carotid duplex using the Carotid Endarterectomy Trial North American Symptomatic Method  with coordination of radiology department, HA1C, and lipid profile typically including low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglycerides, and total cholesterol. Severity of stroke was assessed by the NIHSS and classified as follows: 1–4 minor stroke, 5–15 moderate stroke, 16–20 moderate to severe stroke, and 21–42 severe stroke .
Control group underwent the following: clinical history and examination, and ankle-brachial index measurement.
Statistical analysis of data
The collected data were coded, tabulated, and statistically analyzed using IBM SPSS statistics (Statistical Package for Social Sciences) software version 22.0, IBM Corp., Chicago, USA, 2013. Descriptive statistics were done for quantitative data as minimum and maximum of the range as well as mean ± SD (standard deviation) for quantitative parametric data, while it was done for qualitative data as the number and percentage. Odd ratio (OR) and its 95% confidence interval (CI) were calculated. Inferential analyses were done for quantitative variables using independent t test in cases of two independent groups with parametric data. In qualitative data, inferential analyses for independent variables were done using chi-square test for differences between proportions. Correlations were done using Pearson correlation for numerical parametric data. The level of significance was taken at P value < 0.050 as significant; otherwise, non-significant. The p value is a statistical measure for the probability that the results observed in a study could have occurred by chance.