Administration of abciximab to patients receiving tirofiban or eptifibatide: effect on platelet function.

OBJECTIVES: The goal of this study was to evaluate platelet function and to preliminarily assess the clinical safety of sequential treatment with tirofiban or eptifibatide followed by abciximab in patients undergoing percutaneous coronary intervention (PCI). BACKGROUND: An increasing number of acute coronary syndrome (ACS) patients are treated early with tirofiban or eptifibatide. Some later require PCI and may benefit from switching to abciximab, for which long-term benefits have been reported. METHODS: Fifty ACS patients planned for PCI were enrolled. Twenty-five patients received tirofiban followed by abciximab. Ten patients received eptifibatide followed by abciximab. Fifteen patients received only abciximab. All patients had blood samples drawn six times during the therapeutic course. Platelet function was evaluated by ADP- and TRAP-induced aggregation, flow cytometry analysis of fibrinogen binding and the cone and plate(let) analyzer, which tests shear rate-dependent platelet activation. RESULTS: Administered after tirofiban, abciximab caused a significant further decline in platelet function, as evidenced by all methods. Administered after eptifibatide, abciximab caused a significant further reduction in platelet function, as assessed by the cone and plate(let) analyzer and fibrinogen binding methods. The platelet inhibition achieved by the combination therapy was always greater than or equal to that achieved by abciximab alone. There were no major bleeding or severe thrombocytopenia episodes. Three of the 35 combination therapy patients and one of the 15 who received abciximab alone had minor bleeding. CONCLUSIONS: This is the first in vivo study of combination intravenous platelet glycoprotein IIb/IIIa inhibitor therapy. Administration of abciximab immediately after tirofiban or eptifibatide therapy effectively inhibits platelet function and appears to be safe.

Noninvasive in vivo human coronary artery lumen and wall imaging using black-blood magnetic resonance imaging.

BACKGROUND: High-resolution MRI has the potential to noninvasively image the human coronary artery wall and define the degree and nature of coronary artery disease. Coronary artery imaging by MR has been limited by artifacts related to blood flow and motion and by low spatial resolution. METHODS AND RESULTS: We used a noninvasive black-blood (BB) MRI (BB-MR) method, free of motion and blood-flow artifacts, for high-resolution (down to 0.46 mm in-plane resolution and 3-mm slice thickness) imaging of the coronary artery lumen and wall. In vivo BB-MR of both normal and atherosclerotic human coronary arteries was performed in 13 subjects: 8 normal subjects and 5 patients with coronary artery disease. The average coronary wall thickness for each cross-sectional image was 0.75+/-0.17 mm (range, 0.55 to 1.0 mm) in the normal subjects. MR images of coronary arteries in patients with >/=40% stenosis as assessed by x-ray angiography showed localized wall thickness of 4.38+/-0.71 mm (range, 3.30 to 5.73 mm). The difference in maximum wall thickness between the normal subjects and patients was statistically significant (P<0.0001). CONCLUSIONS: In vivo high-spatial-resolution BB-MR provides a unique new method to noninvasively image and assess the morphological features of human coronary arteries. This may allow the identification of atherosclerotic disease before it is symptomatic. Further studies are necessary to identify the different plaque components and to assess lesions in asymptomatic patients and their outcomes.

Mycobacterial cervical adenitis in Auckland: diagnosis by fine needle aspirate.

AIMS: To evaluate the role of fine needle aspiration (FNA) in the diagnosis of tuberculous and non-tuberculous mycobacterial cervical adenitis in Auckland, and to examine the demography of these conditions. METHOD: We reviewed the medical records of cases of mycobacterial adenitis in the Auckland region between 1991-1994. Cases were identified by cross-checking the reference mycobacteriology laboratory records, all hospital cytology reports from cases who had an FNA taken from the neck region and hospital discharge diagnosis databases. RESULTS: Twenty-two cases of M tuberculosis adenitis, and 13 of M avium adenitis were identified. No FNAs were smear positive for mycobacteria. The FNA from 6/18 (33%) cases of M tuberculosis adenitis and from 4/6 (66%) M avium adenitis cases were culture positive. Bacteriological confirmation was obtained (by various methods) in 72% of tuberculous and in 100% of M avium adenitis cases. The clinical picture was different for the two organisms: tuberculous adenitis occurred mainly in caucasian adults, while M avium adenitis cases were predominantly caucasian children. None of the confirmed cases of tuberculous adenitis demonstrated drug resistance to standard anti-tuberculous agents. CONCLUSIONS: (1) Clinicians should more consistently include mycobacterial tests when investigating neck lumps. (2) FNA is not a reliable diagnostic test for mycobacterial cervical adenitis in New Zealand. Here, FNA should only be regarded as a screening test for mycobacterial adenitis. If anti-tuberculous treatment is required before it is known whether FNA has provided a positive culture, excision biopsy should first be performed to identify the mycobacterium and its susceptibility pattern.