P590Wave intensity analysis and arterial stiffness in stroke patients

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Abstract

Introduction

Wave intensity (WI) is a recently evolved haemodynamic index reflecting ventriculoarterial interaction. WI analysis includes a forward-traveling compression wave (W1), forward-traveling expansion wave (W2) and backward-traveling compression wave (NA – negative area), integrating reflected waves from cerebral vasculature. In recent years arterial stiffness (AS) measurement is increasingly used in the clinical assessment of patients as a noninvasive method for cardiovascular risk assessment.

Objective

The purpose of the present study was to evaluate and compare WI and AS parameters in a stroke patients group and control group. We also hypothesized that patients with ischemic stroke would have higher ipsilateral compared to contralateral NA values which could be connected to an increase in ipsilateral AS.

Methods

We studied 42 stroke patients (66 ± 14 y, 53% female) and compared them with 40 matched controls without cerebrovascular disease. WI and AS analysis was performed bilaterally on the common carotid artery. We evaluated the following parameters: WI indices (W1, W2 and NA - mmHg m/s3) and AS indices (β index, elastic modulus "pressure-strain" – Ep, arterial compliance – AC, augmentation index – AI and local pulse wave velocity – PWVβ).

Results

Demographic characteristics, risk factors and clinical parameters were similar between stroke patients and controls. We did not find any significant differences in AS indices and WI parameters between these two groups of patients.

Results

Stroke patients were further subdivided, regarding ischemic disturbances location, as follows: right middle cerebral artery – 22 patients (53%); left middle cerebral artery – 17 patients (41%); vertebrobasilar system – 3 patients (5%). Comparing the ipsi- and contralateral (regarding stroke location) derived WI and AS indices in the 1st two groups, we found the following: all AS and WI parameters did not differ significantly between carotid arteries with the exception of NA, which was significantly higher, ipsilateral of the ischemic event: 66.1 ± 64.9 and 31.3 ± 18.5, p < 0.001.

Conclusion

Stroke patients demonstrated ipsilateral NA increase, implying greater wave reflection of the cerebral vasculature on the side of the ischemic disturbance. This, however, was not a result from an ipsilateral increase in arterial stiffness indices (including pulse wave velocity). Whether this increase in wave reflectivity could be attributed to a shorter wave propagation distance and / or development of new reflection sites, remains to be further elucidated.

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