Aortopulmonary collateral flow quantification by MR at rest and during continuous submaximal exercise in patients with total cavopulmonary connection.

BACKGROUND: Aortopulmonary collateral flow is considered to have significant impact on the outcome of patients with single ventricle circulation and total cavopulmonary connection (TCPC). There is little information on collateral flow during exercise. PURPOSE: To quantify aortopulmonary collateral flow at rest and during continuous submaximal exercise in clinical patients doing well with TCPC. STUDY TYPE: Prospective, case controlled. POPULATION: Thirteen patients with TCPC (17 (11-37) years) and 13 age and sex-matched healthy controls (18 (11-38) years). FIELD STRENGTH: 1.5T; free breathing; phase sensitive gradient echo sequence. ASSESSMENT: Blood flow in the ascending and descending aorta and superior vena cava were measured at rest and during continuous submaximal physical exercise in patients and controls. Systemic blood flow (Qs ) was assumed to be represented by the sum of flow in the superior caval vein (Qsvc ) and the descending aorta (QAoD ) at the diaphragm level. Aortopulmonary collateral flow (Qcoll ) was calculated by subtracting Qs from flow in the ascending aorta (QAoA ). STATISTICS: Mann-Whitney U-test and Wilcoxon test for comparison between groups and between rest and exercise. RESULTS: Absolute collateral flow in TCPC patients at rest was 0.4 l/min/m2 (-0.1-1.2), corresponding to 14% (-2-42) of Qs . Collateral flow did not change during exercise (difference -0.01 (-0.7-1.0) l/min/m2 , P = 0.97). TCPC patients had significantly lower Qs at rest (2.5 (1.6-4.1) vs. 3.5 (2.6-4.8) l/min/m2 , P = 0.001) and during submaximal exercise (3.2 (2.0-6.0) vs. 4.8 (3.3-6.9) l/min/m2 , P = 0.001), compared to healthy controls. The increase in Qs with exercise was also significantly lower in patients than in healthy controls (median 0.6 vs. 1.2 l/min/m2 , P < 0.02). DATA CONCLUSION: Clinical patients doing well with TCPC have significant aortopulmonary collateral flow at rest (14% of Qs ) compared to healthy controls, which does not change during submaximal exercise. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:1509-1516.

Mastitis vaccination using a commercial polyvalent vaccine or a herd-specific Staphylococcus aureus vaccine. Results of a controlled field trial on a dairy farm.

UNLABELLED: Objective of this study was the improvement of selected parameters of udder health by mastitis vaccination in a dairy herd with elevated bulk milk somatic cell counts and Staphylococcus (S.) aureus as predominant mastitis causing pathogen. MATERIAL AND METHODS: On a dairy farm, pregnant heifers (status group [SG] 1; n = 181) as well as cows stratified for their udder health state (classification based on results of cytobacteriological investigations of quarter milk samples obtained before dry cow therapy [MS0]) (SG 2-4; n = 416) were randomly assigned to one of the following vaccination groups (VG): Startvac® (VG SV), Bestvac® Rind Mastitis (containing herd-specific S. aureus-strains; VG BV) and the unvaccinated control (VG Co, placebo), respectively. The collected data (5 [MS5] and 52 [MS52] days in milk [DIM]: quarter milk somatic cell count [QSCC] and bacteriological investigation of quarter milk samples; dairy herd improvement test [DHIT] days 1-10: milk yield and individual cow somatic cell count; until 305 DIM: clinical mastitis cases) were compared between the VG within their SG. RESULTS: S. aureus prevalences were significantly lower in VG SV (p < 0.001) and VG BV (p = 0.006) within SG 3 and in VG SV (p = 0.008) within SG 4, respectively, in comparison to VG Co. Milk yields (DHIT days [p = 0.042] and 305-day milk yield [p = 0.040]) were significantly less in VG SV within SG 4 compared to VG Co. Significant different changes over time in comparison to VG Co indicating a vaccine effect during lactation were only observed for QSCC within SG 4 for VG BV (p = 0.017; increase towards MS52) and for S. aureus prevalence within SG 3 for VG BV (p < 0.001; opposing trends from MS0 towards MS52). All other interactions of time and VG under investigation were not significant in any of the SG. Furthermore, there were no descriptive differences in the incidence of clinical mastitis and duration of a necessary mastitis therapy, respectively, between the VG within their SG. CONCLUSION: In this field study, the application of two different mastitis vaccines was not an appropriate tool to improve the considered parameters of udder health sustainably.