Radiologic importance of a high-resistive vertebral artery Doppler waveform on carotid duplex ultrasonography.

OBJECTIVE: The appearance of the vertebral artery (VA) waveform on a pulsed Doppler examination performed during standard carotid duplex ultrasonography (CDU) may suggest vertebrobasilar disease. We sought to determine the radiographic importance of high-resistive (HR) pulsed Doppler VA waveforms seen on CDU. METHODS: The Noninvasive Vascular Laboratory database was queried for CDU studies noting the HR VA Doppler signal. Studies with unilateral or bilateral HR and antegrade VA waveforms with correlative neuroimaging studies within 60 days were included. Imaging reports were reviewed to determine the following: (1) a normal VA; (2) at least moderate distal VA or basilar artery (BA) stenosis, occlusion, or dissection; (3) a congenitally diminutive VA; or (4) other abnormalities. RESULTS: Of 1338 studies with 1 or more HR VA waveforms, 79 studies met all inclusion criteria (n = 157 arteries) and had adequate correlative neuroimaging. There were 90 HR VAs, and HR waveforms were equally distributed between right and left sides. The mean peak systolic velocity of HR versus low-resistive (LR) VAs was 51.7 versus 63.6 cm/s (P = .04); the mean end-diastolic velocity of HR versus LR VAs was 4.6 versus 17.3 cm/s (P < .001); and the resistive index of HR versus LR VAs was 0.92 versus 0.73 (P < .001). Of all HR VAs, 18.9% were normal; 38.9% had distal vertebrobasilar stenosis or occlusion; 35.6% were congenitally diminutive; and 6.7% had other abnormalities (proximal stenosis, excessive tortuosity, fibromuscular dysplasia, and BA hypoplasia). CONCLUSIONS: The finding of an HR spectral Doppler signal in the VA was associated with major vertebrobasilar disease (46% of cases) and should prompt additional neuroimaging in the appropriate clinical situation.

Warfarin plus aspirin after myocardial infarction or the acute coronary syndrome: meta-analysis with estimates of risk and benefit.

BACKGROUND: After the acute coronary syndrome, adding warfarin to standard aspirin therapy decreases myocardial infarction and stroke but increases major bleeding. PURPOSE: To quantify the risks and benefits of warfarin therapy after the acute coronary syndrome. DATA SOURCES: MEDLINE from 1990 to October 2004. Additional data were obtained from study authors. Clinical risk factors were used to classify hypothetical patients into cardiovascular and bleeding risk groups on the basis of published data. STUDY SELECTION: Randomized trials comparing intensive warfarin therapy (international normalized ratio > 2.0) plus aspirin with aspirin alone after the acute coronary syndrome. DATA EXTRACTION: Two reviewers independently selected studies and extracted data on study design; quality; and clinical outcomes, including myocardial infarction, stroke, revascularization, death, and major and minor bleeding. Rate ratios for outcomes were calculated and pooled by using the method of DerSimonian and Laird. DATA SYNTHESIS: Ten trials involving a total of 5938 patients (11,334 patient-years) met the study criteria. Compared with aspirin alone, warfarin plus aspirin was associated with a decrease in the annual rate of myocardial infarction (0.022 vs. 0.041; rate ratio, 0.56 [95% CI, 0.46 to 0.69]), ischemic stroke (0.004 vs. 0.008; rate ratio, 0.46 [CI, 0.27 to 0.77]), and revascularization (0.115 vs. 0.135; rate ratio, 0.80 [CI, 0.67 to 0.95]). Warfarin was associated with an increase in major bleeding (0.015 vs. 0.006; rate ratio, 2.5 [CI, 1.7 to 3.7]). Mortality did not differ. LIMITATIONS: Two large studies provided most of the data. Studies did not include coronary stenting, and results should not be applied to patients with stents. Relative risk reductions may not be consistent across risk groups. CONCLUSIONS: For patients with the acute coronary syndrome who are at low or intermediate risk for bleeding, the cardiovascular benefits of warfarin outweigh the bleeding risks.