Improvement in aortic valve area using a new "hour glass" shaped valvuloplasty balloon compared with standard cylindrical balloons in severe aortic stenosis patients.

AIM: Balloon aortic valvuloplasty (BAV) has reemerged with transcatheter valve therapy. Cylindrical balloons have been the device of choice despite limitations. An hour glass shaped balloon may permit enhanced fixation and broader leaflet opening without annular compromise. METHODS: We report our initial BAV experience using the V8 balloon (InterValve Inc.) in 20 consecutive patients compared to 20 patients from a 403-patient BAV database using cylindrical balloons. Patients were propensity matched on a 1:1 basis by age, gender, left ventricular ejection fraction (LVEF), baseline aortic valve area (AVA) and Society of Thoracic Surgery (STS) mortality risk score. End points included change in AVA and aortic insufficiency (AI) by echocardiography. New atrioventricular conduction defects (AVCD), need for post procedure pacemaker were documented. Major adverse events (MAE) included procedure related death, emergency surgery or stroke. RESULTS: V8 and cylindrical balloon groups were similar across age, gender, LVEF, AVA and STS score. The change in AVA from baseline to post-procedure strongly trended towards being larger in the V8 group than cylindrical balloon group (mean [SD]; 0.30±0.23 cm2 vs. 0.17±0.21 cm2; P=0.063). There were no differences in outcomes for degree of AI, AVCD, need for pacemaker or MAE. CONCLUSION: Preliminary findings in this small experience suggest an advantage for enhancing AVA when using the V8 compared with cylindrical balloons. Additionally, there was no evidence of increased AI, AVCD or MAE.

Factors influencing the accuracy of the national reference system total cholesterol reference method.

Previous comparisons between the Reference and Definitive Methods for measuring serum cholesterol have demonstrated a small but persistent positive bias in the Reference Method, averaging about +1.6%. Here we describe the results of further investigations designed to better characterize the nature of this bias. Analysis of a well-characterized model serum sample (SRM 909) suggests that more than half of the difference in cholesterol values determined by the two methods is the result of small contributions from cholesterol precursor sterols and phytosterols, which are also measured for the Reference Method. An additional significant contribution may be from cholesterol oxidation products, particularly 7-hydroxycholesterol isomers, which are active in the Liebermann-Burchard reaction. The 7-hydroxycholesterol in SRM 909, most of which appeared to be already present in the serum rather than formed during saponification, may account for as much as 20% of the observed difference between the methods. Contributions from other possible sources, including impurities in the cholesterol standard and incomplete saponification of cholesteryl esters, are very small. Because the observed bias is both quite small and consistent among samples, the cholesterol Reference Method continues to meet all of the requirements generally expected for a dependable and effective Reference Method.

Scanning electron microscopy of pulmonary vascular endothelium in rats with hypoxia-induced hypertension.

Scanning electron microscopy was used to study the endothelial surface of the pulmonary trunk, artery, and vein in normobaric control rats as well as in rats exposed to hypobaric hypoxia for 7 and 21 days. The individual endothelial cells of the normobaric pulmonary trunk and hilar artery were flat and slightly elongated with elevated nuclear regions, and those of the intermediate-sized artery were more elongated and had more microvilli than the large arteries studied. Their endothelial cell boundaries were outlined by beaded cytoplasmic projections. The surfaces of the normobaric hilar and intermediate-sized veins were smooth and demonstrated numerous longitudinal streaks. These venous endothelial cells were elongated and their cell boundaries were outlined by low discontinuous marginal folds. Exposure to hypobaric hypoxia caused the following changes on the arterial surface: elevation of the endothelial cells; formation of microvilli-rich cell clusters; formation of hollow defects; and the attachment of leukocytes. Hypobaric hypoxia also caused the disappearance of the longitudinal streaks and the occurrence of microvilli-rich cells in the hilar veins. The endothelial surface modifications in the hypobaric rats could be related to thickening of the endothelium, intimal edema, increased intimal connective tissue, luminal invasion of leukocytes, and increased endothelial cell proliferation, known to occur in systemic arteries of hypertensive animals.