BACKGROUND AND PURPOSE:Clopidogrel resistance is blamed for thromboembolic complications in neurovascular stent placement. Platelet-function assays are weakly standardized. The aim of this study was to correlate the results of 3 different platelet-inhibition measurements (from light transmission aggregometry, the VerifyNow P2Y12 test, and the Multiplate analyzer) and their relation to periprocedural thromboembolic complications in elective neurovascular stent placement.

Pressure measurements in arterial feeders of arteriovenous malformations (AVMs) can be easily acquired during endovascular treatment procedures. In this study, mean arterial pressure values in arterial feeders (Pfed) of brain AVMs were determined using a pressure measuring system connected to a standard microcatheter. A total of 148 measurements were performed in 139 patients. Mean systemic arterial pressure values were subtracted for correction. The levels of correlation between the pressure values and various clinical parameters (i.e., AVM location, size, previous hemorrhage) and pathoanatomical features of the AVM (e.g., nidus structure, number of draining veins) were determined. Pfed values were 54.5 mmHg on average. Pfed was lower in more distally located AVMs, in larger lesions and in AVMs with multiple drainage veins. Pressure values were significantly higher in patients with previous hemorrhage and in smaller AVMs. Our results support the importance of hemodynamic parameters in determining the presentation of AVMs. More extensive studies using this simple technique may further elucidate these mechanisms and may result in improved criteria for patient selection and reduction of complications.

Benign obstruction of the pylorus may either be con¬ genital or acquired. Of the congenital variety, we may dis¬ tinguish two forms,--one which presents itself as a complete closure of the first part of the duodenum and pylorus, the in¬ testinal tract at this point being either converted into a fibrous band, or showing a stenosis of very high degree, and another, generally at the outset, moderate narrowing, which is always situated at the pylorus, and becomes clinically apparent only after several months of life. The first variety is supposed to he the result of a foetal peritonitis,'of probably syphilitic ori¬ gin, and generally causes death in a few days. The second, known as congenital hypertrophy, is generally ascribed to a hyperplasia of the inner circular muscular layer of the pylorus. Pfaundler, in a critical analysis of all cases reported, has lately questioned the correctness of this view, based on direct meas¬ urements of the thickness of the pyloric wall. He calls at¬ tention to the fact that a normal stomach, with contraction of the pylorus persisting after death, presents identically the same appearance as is found in so-called cases of congenital hypertrophy. The symptoms during life arc due, according to Pfaundler, to gastro-intestinal disorders, so frequent in young infants. The appearance of the pylorus after death is

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