[Bacterial susceptibility testings of the lower airways of diseased dogs]

OBJECTIVE

In this retrospective study over 5 years the bacterial flora of the deep airways of diseased dogs was sampled using bronchioalveolar lavage and its in-vitro susceptibility to numerous antimicrobial agents was analysed.

MATERIAL AND METHODS

Susceptibility testing of bacterial isolates from 84 dogs performed from 2004 to 2009 were evaluated and compared to data collected in 1999/2000.

RESULTS

The 99 bacterial isolates comprised Pasteurella spp. (27.3%), Bordetella bronchiseptica (20.2%), Staphylococcus spp. (18.2%), Escherichia coli (15.2%), Klebsiella spp. (8.1%), Pseudomonas spp. (7.0%), and Streptococcus spp. (4.0%). Lavage samples of eight dogs revealed simultaneous occurrence of more than one species. The majority of the tested Bordetella bronchiseptica-isolates were susceptible to fluoroquinolones as well as tetracycline, doxycycline and polymyxin B. The number of amoxicillin/clavulanic acid- and chloramphenicol-resistant isolates decreased compared to 1999/2000. The increase of chloramphenicol-susceptible isolates was statistically significant. The tested Staphylococcus-isolates revealed a susceptibility to fluoroquinolones, amoxicillin, cephalexin, doxycycline, and polymyxin B. Compared to the earlier study, a major portion exhibited susceptibility to chloramphenicol and tetracycline. None of the Klebsiella spp. tested in 1999/2000 was resistant to enrofloxacin, whereas only 62.5% of the isolates examined during 2004-2009 were susceptible. A susceptibility of all tested Klebsiella -isolates was detectable with respect to polymyxin B. Regarding E.coli , none of the tested antibiotics revealed an in-vitro activity against all of the tested isolates. The increase of amoxicillin/clavulanic acid-resistant isolates was statistically significant.

CONCLUSION AND CLINICAL RELEVANCE

The study demonstrates the benefits of bronchioalveolar lavage as a diagnostic tool to ensure a responsible utilisation of antibiotics. Most of the tested bacterial isolates were susceptible to fluoroquinolones.

Spherical dilatation of the apex in failing left ventricles: a target for surgical remodelling techniques

AIM

The present study investigates the geometry of failing left ventricles with a special focus on apical deformation. A new surgical remodelling technique is evaluated.

METHODS

In 124 patients with impaired left ventricular function (EF<40%) undergoing coronary artery bypass grafting (CABG) left ventricular (LV) geometry was evaluated by MRI scanning before and after surgery. Besides the sphericity index (SI) two further indices were calculated, longitudinal EF (LEF) and an apical conicity index (ACI). The results were compared to 15 patients with coronary heart disease and normal LV function and 10 test persons. In 35 patients with impaired LV function perpendicular apical compression (AC) stitches were placed.

RESULTS

In failing left ventricles indexed LV length increased (5.3 ± 0.6 cm/m2 vs. 4.7 ± 0.8 cm/m2 in control patients and 4.6 ± 0.3 cm/m2 in test persons, P=0.03). LEF was reduced (6% ± 4 versus 22% ± 6 and 19% ± 7 P=0.04). The classical SI was 0.56 ± 0.06 in heart failure patients, 0.50 ± 0.05 in control patients and 0.48 ± 0.04 in test persons. The ACI were 0.75 ± 0.06, 0.58 ± 0.06 and 0.57 ± 0.04 respectively (P<0.05), indicating a pronounced dilatation at the apex. After apical compression LEF improved to 15 ± 1%, the ACI to 0.64 ± 0.04 (P=0.04). LVEDV (166 ± 11 mL [AC] vs. 196 ± 14 mL [without AC]) as well as LV-EF (48 ± 3% [AC] vs. 36 ± 2% [without AC]) significantly improved only after remodelling (P<0.05).

CONCLUSION

Apical compression improved ventricular geometry and ventricular function in patients with dialatation of the left ventricular apex.

[The influence of cardiopulmonary bypass operation on the biodistribution of 99mTc-HMPAO-labelled granulocytes - Evaluation in pigs by planar scintigraphy and section-analyses]

AIM

of the study was to evaluate the influence of an extra corporal perfusion (cardiopulmonary bypass operation - cpb) on activation and biodistribution of (99m)Tc labelled granulocytes in pigs with and without inhibition of the granulocytes by a leukocyte inhibition module (LIM). The cpb is often related to an activation of granulocytes resulting in an inflammatory answer. The biological mechanisms are unsolved yet. First trials of our group showed that LIM may inhibit the activation of neutrophils and therefore antagonize a cpb-caused impairment of cardiac function. This study is the continuation of these experiments with a higher number of animals and the focus on scintigraphic imaging. ANIMALS, MATERIAL, METHODS: 39 German landrace pigs were subdivided into three groups: group A (control) median sternotomy without cpb, group B with cpb, group C with LIM in addition to cpb. After labelling with (99m)Tc-HMPAO autologues granulocytes were reinjected. Subsequently to cpb, the animals underwent scintigraphic imaging. Quantification was performed with ROI evaluation and with tissue samples (section analysis) examined in a well counter.

RESULTS

A high uptake of (99m)Tc-HMPAO was found in the liver. The count rates in brain, heart, lung, spleen and kidneys were far below. The amount of 99mTc-activity in the organ related to the half life corrected administered activity [%] was for the tissue samples (group A/B/C): brain 0.01/0.02/0.03; lung 12.1/8.3/11.5; heart 0.35/0.54/0.42; kidney 1.24/0.87/1.02; spleen 4.0/4.0/4.5, liver 16.8/20.9/19.6. The count rates determined by ROI-evaluation of the scintigraphic images related to the total count rate in the image [%] were (group A/B/C): brain 1.1/0.9/1.0; lung 15.6/10.4/12.2; heart 4.0/3.5/3.4; kidney 4.0/2.9/3.2; spleen 7.6/7.7/9.5, liver 23.1/36.7/31.4. A significant difference in the tracer uptake between the groups could neither be detected by scintigraphic imaging nor evaluation of tissue samples.

CONCLUSION

Scintigraphic imaging as well as section analysis showed a comparable biodistribution of the tracer. Therefore, the initial results of our group were not confirmed with a considerably higher number of animals. Neither cpb nor the use of the LIM influenced distribution of 99mTc-labelled granulocytes in pigs significantly.

Pre-filling of the extracorporeal circuit with autologous blood is safe, but not effective in optimizing biocompatibility in high-risk patients

OBJECTIVES

Haemodilution resulting from crystalloid priming of the cardiopulmonary bypass circuit represents a major risk factor for blood transfusions in high-risk cardiac surgery patients. We designed this study to evaluate the effects of antegrade autologous priming (AAP) on reducing perioperative blood transfusion and markers of the inflammatory response in older patients (>75 years).

METHODS

Seventy-two patients undergoing first-time coronary bypass and/or aortic valve replacement were prospectively randomised to a cardiopulmonary bypass (CPB) with or without AAP. AAP was performed by adding the patient's own blood to the prime solution (mean 280 ml). Perfusion and anaesthetic techniques were as usual. The haematocrit was maintained at a minimum of 21% during CPB. Patients were well matched for all preoperative variables, including established transfusion risk factors. The primary endpoint was the requirement of red cell transfusion. The surrogate endpoints were renal function, inflammatory response and ischaemic parameters. Blood samples were drawn pre- and intraoperatively and at intervals of 6 hours till POD 6.

RESULTS

Current analysis shows no differences in patients receiving homologous packed red cell transfusions. Also, markers of the inflammatory response (IL6, IL8), renal function (cystatin C, creatinine) and myocardial ischaemia (troponin T, CK-MB) were comparable in both groups (p>0.05). Clinical outcomes were similar with respect to pulmonary, renal and hepatic function, length of ICU stay and hospital stay.

CONCLUSION

These data suggest that antegrade autologous priming is a safe procedure, but an ineffective way for improving biocompatibility and reducing the need for blood transfusion in older patients.

[Mitral valve surgery in patients with extensively calcified mitral annulus: long-term echocardiographic and clinical follow-up]

OBJECTIVE

The aim of this study was the analysis of long-term results in patients with hemodynamically significant mitral valve disease due to extensively calcified mitral annulus who underwent decalcification and patch reconstruction.

PATIENTS AND METHODS

Between 1996 and 2008 a total of 109 patients underwent surgery for extensive calcification and severe mitral insufficiency and mitral stenosis. The mean age of the patients (65 women and 44 men) was 66.4 ± 13.8 years. In 53 patients (49%) mitral valve repair was performed and the remaining 56 patients (51%) received a mitral valve replacement. Of the patients 64 (59%) required concomitant surgery. The mean follow up time was 96 ± 48 months.

RESULTS

The in-hospital and late mortality was 8.3% (9 patients) and 25.6% (28 patients), respectively. The actuarial survival rates at 5, 8 and 12 years were 88.1%, 76.2% and 66.1%, respectively. Echocardiographic follow-up presented a mitral insufficiency grade III in 4 patients (6%). None of the patients had a mitral insufficiency grade IV. A significant reduction of left atrium diameter, of the LVEDD as well as the mean transvalvular gradient was observed. Freedom from reoperation at 5 and 8 years was 96.4% and 91.8%, respectively. Systemic hypertension, diabetes mellitus, age older than 65 years, concomitant aortic valve replacement, concomitant procedures, chronic renal insufficiency and cardiac decompensation in the medical history were found to be predictors for significantly increased early or late mortality.

CONCLUSION

The long-term results strongly suggest that en bloc decalcification and patch reconstruction of the mitral annulus can be safely undertaken in high risk patients.