Detection of Subclinical Atherosclerosis in Subclavian Arteries of Subjects with Vascular Risk Factors and Normal Carotid Ultrasound.

BACKGROUND AND PURPOSE: Most risk scores that use imaging methods to determine the presence of subclinical atherosclerosis assess the carotid and coronary arteries. The value of assessing subclavian arteries to improve the predictive capacity of traditional imaging studies is not known. MATERIALS AND METHODS: We studied subjects without cardiac, cerebral, or peripheral vascular symptoms and normal carotid ultrasound. They had at least 1 traditional vascular risk factor. We assessed prevalence of atherosclerotic plaques in the right subclavian artery. RESULTS: We studied 625 subjects aged 54 ± 12. Most participants had 1 vascular risk factor. Using the Framingham Heart Study score, 62% were categorized as low risk, 29% intermediate risk, and 9% high risk. A total of 169 subjects (27%) had atheromatous plaques in the right subclavian artery. The prevalence of this finding was greater in women than in men (64% versus 36%, P < .00001) and was greater in subjects older than 54 years than in younger individuals (72% versus 28%, P < .00001). Plaques in the subclavian artery were present in 27% of subjects with high risk, 34% with intermediate risk, and 24% with low risk. CONCLUSIONS: Plaques in subclavian arteries are often detected in asymptomatic subjects with vascular risk factors and normal carotid arteries even with low vascular risk scores. Study of the subclavian arteries appears as a simple strategy for the detection of subclinical atherosclerosis. Its role for improving cardiovascular risk scales and predicting coronary and cerebrovascular events needs to be further explored.

Cerebrovascular effects of cilostazol in patients with atherosclerotic disease.

BACKGROUND: Cilostazol is a potent selective inhibitor of phosphodiesterase-3 of proven efficacy in intermittent claudication. It has antiplatelet effect and produces vasodilatation in several vascular territories. This drug has been approved in some countries for the prevention of recurrence of cerebral infarction. Limited data in patients with cerebral infarcts suggest improvement in cerebral blood flow. Dilatation of cerebral vessels with carbon-dioxide challenge can be assessed by transcranial Doppler technique. The percentage increase in blood flow velocity is called cerebral vasomotor reactivity (CVR). OBJECTIVE: In this investigation we sought to measure CVR before and after oral administration of cilostazol. METHODS: We studied patients with risk factors for atherosclerosis before they received cilostazol (100 mg twice daily) for intermittent claudication. CVR was assessed by measuring bilateral middle cerebral artery blood flow velocity during normoventilation and after 3 minutes of breathing 8% carbon dioxide. One average value was obtained from each patient. CVR was measured the day before cilostazol first dose, at 1 month, and 3 to 6 months later. RESULTS: We examined 9 patients (8 men and 1 woman) aged 67.6 +/- 8.4 years. All patients had hypertension, 5 had diabetes, 4 were smokers, 5 had high cholesterol levels, and 4 had coronary artery disease. CVR was 54.4 +/- 14.4% at baseline, and increased to 64.2 +/- 18.6% after 1 month (P < .05) and to 67.1 +/- 13.3% at 3 to 6 months later (P < .01). CONCLUSION: Our findings suggest that cilostazol increases CVR in patients with atherosclerotic disease.

Transcranial Doppler monitoring during head upright tilt table testing in patients with suspected neurocardiogenic syncope.

The aim of the present study was to evaluate the mechanism of cerebrovascular autoregulation in patients with neurocardiogenic syncope using bilateral transcranial Doppler (TCD) monitoring during head upright tilt table testing (HUT). Two hundred and six patients were prospectively studied. One hundred and fifty-nine subjects (77%) had a prior history of syncope and 47 (23%) had presyncope. Ninety-nine patients (48%) had syncope or presyncope during HUT with a 76% fall in diastolic middle cerebral artery blood flow velocity (D-MCA-BFV). Systolic MCA-BFV (S-MCA-BFV) fell by 33%. Deepening of the dicrotic notch in the Doppler waveform always preceded the fall in D-MCA-BFV. Patients without syncope or presyncope (n=96) had smaller changes in cerebral blood flow velocities during HUT and only twenty-two subjects had transient deepening of the dicrotic notch. Eleven subjects had presyncope during HUT due to an exaggerated response to nitrates with progressive arterial hypotension without bradycardia and changes during TCD monitoring that were intermediate between positive and negative HUT. In conclusion, patients with neurocardiogenic syncope have changes in cerebral blood flow during the event. TCD monitoring during HUT helps to assess these alterations.