AORTIC DISTENSIBILITY IN PATIENTS WITH CEREBROVASCULAR-DISEASE

1. Non-invasive aortic compliance measurements have been used previous ly to assess the distensibility of the aorta in several pathological c onditions associated with increased cardiovascular risk. We set out to establish whether aortic compliance is abnormal in patients with stro ke. 2. Pulse wave velocity measurements of thoracoabdominal aortic com pliance were made in 20 stroke patients and 25 age- and sex-matched ho spitalized, non-stroke control subjects putatively free of cardiovascu lar disease. Since compliance varies with non-chronic changes in blood pressure, a blood pressure corrected index of aortic distensibility, Cp, was calculated. 3. Aortic compliance was significantly reduced in patients with stroke compared with non-stroke control subjects (0.46 /- 0.27 versus 0.86 +/- 0.34%/10mmHg, P<0.0002), corresponding with hi gher values for pulse wave velocity. Stroke patients also had signific antly higher systolic and diastolic blood pressures (P<0.02 and P<0.00 2 respectively) and total cholesterol levels (P<0.004) than the contro l subjects, Calculation of Cp did not alter the observation of stiffer aortas in the stroke cohort (P<0.0007). 4. In both stroke patient and control cohorts, as expected, inverse trends were observed between ao rtic compliance and blood pressure. Also as expected, in the control g roup Cp values did not show a relationship with blood pressure (r=0.02 , P=0.092, not significant). However, in the stroke cohort a marked de pendence of Cp on blood pressure was observed (r=-0.48, P=0.03). 5. Tr ansoesophageal echocardiographic studies have recently identified adva nced atherosclerosis in the ascending aorta as a possible source of ce rebral emboli and an independent risk factor for ischaemic stroke. Our observations of significantly stiffer thoracoabdominal aortas in pati ents with stroke lead us to hypothesize that a totally non-invasive as sessment of aortic compliance may potentially prove a useful surrogate marker of such atherosclerotic risk. 6. Blood pressure-corrected indi ces of arterial elastic properties based on normotensive models are wi dely applied in the literature. Our observation that these indices exh ibit a considerable blood pressure dependence leads us to urge caution in the use of such corrections, especially in hypertensive patients.