Biomedical subjects

Hanns Ackermann

Publications and source records attributed to Hanns Ackermann.

22 records · Page 2Linked to original sources

PubMed2003

Change of the mechanical properties of two different balloon catheters with increasing numbers of cycles of resterilization.

An increasing number of centers are reusing PTCA catheters even though manufacturers warrant single use only. This prospective bench laboratory trial addresses the quality of PTCA balloon catheters after up to three resterilization cycles in order to determine whether a larger trial is warranted to discern whether catheters should be reused. Forty PTCA catheters from two different manufacturers (nominal diameters 1.5 and 3.0 mm) were taken from the shelf. An independent institute tested mechanical properties such as burst pressure, nominal diameter, crossing profile, and balloon surface. The crossing profile increased by 22.5%-39.2% with no additional deterioration after repeated sterilizations. The nominal diameter either increased or decreased by a maximum of 47%. In all 1.5 mm balloons, the burst pressure remained above the manufacturers' values, whereas in the 3.0 mm balloons, the value dropped below the rated burst pressure in 40%-50% of the trials. In conclusion, in both catheter types analyzed, reuse was associated with a considerably worse quality, which puts in question their routine clinical use.

Angioplasty, Balloon, Coronary↗

PubMed2003

Multi-detector row CT versus coronary angiography: preoperative evaluation before totally endoscopic coronary artery bypass grafting.

PURPOSE: To assess multi-detector row spiral computed tomography (CT) for preoperative evaluation of patients undergoing totally endoscopic coronary artery bypass grafting and to correlate the data with coronary angiographic and intraoperative findings. MATERIALS AND METHODS: Thirty-six patients preoperatively underwent multi-detector row CT (4 x 1-mm collimation, pitch of 1.5, 500-msec rotation time, retrospective electrocardiographic gating, 1.25-mm effective section thickness) and coronary angiography. Assessment criteria for both techniques were visibility and cardiac course of coronary arteries, localization and degree of stenoses, composition of atherosclerotic plaques, and vascular diameter at anastomosis site. Site for distal bypass anastomosis was recommended. Results at multi-detector row CT were calculated relative to results at coronary angiography and surgery. RESULTS: Multi-detector row CT properly displayed 79.4% (154 of 194) of all surgical relevant coronary segments and 80.4% (434 of 540) of all coronary segments. For coronary angiography, ratios of 88.7% (172 of 194) and 94.6% (511 of 540), respectively, were observed. For detection of calcified plaques, multi-detector row CT results exceeded those at coronary angiography by a difference of 17% (18 of 18 [100%] compared with 15 of 18 [83%]). Hemodynamically relevant stenoses were identified with multi-detector row CT in 76% (42 of 55) of cases. Bridging of coronary segments through either myocardium (four of five) or epicardial fat (two of three) was better identified at multi-detector row CT than it was at coronary angiography (one of five compared with zero of three, respectively). At multi-detector row CT, 76% (28 of 37) of all distal bypass touchdown segments were identified, but at coronary angiography, only 70% (26 of 37) were identified. CONCLUSION: Multi-detector row CT provides extended information about coronary target site and therefore should be regarded as an ideal additive planning tool for complex minimally invasive procedures such as totally endoscopic coronary artery bypass grafting or minimally invasive direct coronary artery bypass grafting.

Adult↗

PubMed2002

Heart-rate-adapted image reconstruction in multidetector-row cardiac CT: influence of physiological and technical prerequisite on image quality.

The purpose of this study was to develop strategies for optimal image reconstruction in multidetector-row cardiac CT and to discuss the results in the context of individual heart rate, cardiac physiology, and technical prerequisite. Sixty-four patients underwent multidetector-row cardiac CT. Depending on the heart rate either a single-segmental reconstruction (SSR) or an adaptive two-segmental reconstruction (ASR) was applied. Image reconstruction was done either antegrade (a) or retrograde (r) in relation to the R-peak. Reconstruction of all data sets was performed at multiple time points within the t-wave/p-wave interval, differing from each other by 50 ms. In addition, each reconstruction was assigned to one of six reconstruction intervals (A-F), each corresponding to a specific event in the cardiac cycle. While no significant time points were found for absolute values, the following interval/reconstruction technique combinations provided significant better image quality: F/r at HR <60 bpm for all coronary segments ( p</=0.004) and at HR 60-65 bpm for segments 5-10 ( p</=0.001); B/a at HR 60-65 bpm for segments 1-4 and 11-15 ( p<0.001) and at HR >65 bpm for all segments ( p</=0.002). The results show that in order to achieve optimal image quality, image reconstruction has to be adjusted to each patient's ECG curve and heart rate individually. The moment of reconstruction should be determined as absolute rather than as relative distance from the previous R-peak.

Algorithms↗

PubMed2002

The influence of sulindac on patients with primary biliary cirrhosis that responds incompletely to ursodeoxycholic acid: a pilot study.

OBJECTIVES: In 30% of patients with primary biliary cirrhosis (PBC) ursodeoxycholic acid (UDCA) causes full biochemical normalization, while 70% are incomplete responders. The only differences between the two groups are the significantly higher cholestasis indices in the incomplete responders. In these patients we investigated whether the strongly choleretic sulindac together with UDCA is superior to UDCA monotherapy. DESIGN AND METHODS: Twenty-three patients with PBC incompletely responding to UDCA monotherapy were entered in the open label study for 12 months. Eleven patients (stage II, seven; III, two; and IV, two) received UDCA (10-15 mg/kg/day) plus sulindac (100-300 mg/day) (Group I). Twelve patients (stage I, six; II, four; III, one; and IV, one) were treated with UDCA alone (Group II). Liver biochemistry, analysis of antimitochondrial, antinuclear, smooth muscle, and liver-kidney-microsomal antibodies, ultrasonography and gastroscopy were done in regular intervals. RESULTS: In Group I all liver indices, IgG, IgM and IgA significantly improved although pretreatment data and stages of the disease tended to be higher than in Group II. In five patients of Group I liver histology improved slightly. Sulindac was well tolerated. The biochemical indices did not further improve on UDCA monotherapy. CONCLUSIONS: Sulindac in combination with UDCA further improves liver biochemistries in patients with PBC who responded incompletely to UDCA alone.

Aged↗