Grading Aortic Valve Stenosis With Dimensionless Index During Pre-cardiopulmonary Bypass Transesophageal Echocardiography: A Comparison With Transthoracic Echocardiography.

OBJECTIVE: The authors hypothesized that grading valvular aortic stenosis (AS) with dimensionless index (DI) during intraoperative pre-cardiopulmonary bypass (pre-CPB) transesophageal echocardiography (TEE) would match the grade of AS during preoperative transthoracic echocardiography (TTE) for the same patients more often than when using peak velocity (Vp), mean pressure gradient (PGm), or aortic valve area (AVA). DESIGN: Retrospective, observational. SETTING: Single university hospital. PARTICIPANTS: The participants in this study included 123 cardiac surgical patients with any degree of AS, who underwent open cardiac surgery between 2010 and 2016 at the Medical University of South Carolina and had Vp, PGm, AVA, and DI values available from reporting databases or archived imaging. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: When using DI, pre-CPB TEE grading of AS severity was 1 grade higher 21.1% of the time and 1 grade lower 13.0% of the time compared with TTE, for an overall disagreement rate of 34.1%. The overall disagreement rates between pre-CPB TEE and TTE for Vp, PGm, and AVA were 39.8%, 33.3%, and 33.3%, respectively. CONCLUSIONS: The authors could not demonstrate that DI was better than Vp, PGm, or AVA at matching AS grades between intraoperative pre-CPB TEE and preoperative TTE. When DI was used, pre-CPB TEE was more likely to overestimate than underestimate the severity of AS compared with TTE. However, when Vp or PGm was used, pre-CPB TEE was more likely to underestimate the severity of AS compared with TTE. A comprehensive approach without overemphasis on 1 parameter should be used for AS assessment by intraoperative TEE.

The antimicrobial activity of mono-, bis-, tris-, and tetracationic amphiphiles derived from simple polyamine platforms.

A series of 34 amphiphilic compounds varying in both number of quaternary ammonium groups and length of alkyl chains has been assembled. The synthetic preparations for these structures are simple and generally high-yielding, proceeding in 1-2 steps without the need for chromatography. Antibacterial MIC data for these compounds were determined, and over half boast single digit MIC values against a series of gram-positive and gram-negative bacteria. MIC variation mostly hinged on the length of the alkyl chain, where a dodecyl group led to optimal activity; surprisingly, the number of cations and/or basic nitrogens was less important in dictating bioactivity. Additional structural variation was prepared in a trisamine series dubbed 12,3,X,3,12, providing a series of potent amphiphiles functionalized with varied allyl, alkyl, and benzyl groups. Tetraamines were also investigated, culminating in a two-step preparation of a tetracationic structure that showed only modestly improved bioactivity versus amphiphiles with two or three cations.