Approbationsentzug wegen Unwürdigkeit und Anspruch auf Wiedererteilung der Approbation

Ohne Zusammenfassung     

Quantitative bone matrix density measurement by water‐ and fat‐suppressed proton projection MRI (WASPI) with polymer calibration phantoms

The density of the organic matrix of bone substance is a critical parameter necessary to clinically evaluate and distinguish structural and metabolic pathological conditions such as osteomalacia in adults and rickets in growing children. Water‐ and fat‐suppressed proton projection MRI (WASPI) was developed as a noninvasive means to obtain this information. In this study, a density calibration phantom was developed to convert WASPI intensity to true bone matrix density. The phantom contained a specifically designed poly(ethylene oxide)/poly(methyl methacrylate) (PEO/PMMA) blend, whose MRI properties (T₁, T₂, and resonance linewidth) were similar to those of solid bone matrix (collagen, tightly bound water, and other immobile molecules), minimizing the need to correct for differences in T₁ and/or T₂ relaxation between the phantom and the subject. Cortical and trabecular porcine bone specimens were imaged using WASPI with the calibration phantom in the field of view (FOV) as a stable intensity reference. Gravimetric and amino acid analyses were carried out on the same specimens after WASPI, and the chemical results were found to be highly correlated (r² = 0.98 and 0.95, respectively) to the WASPI intensity. By this procedure the WASPI intensity can be used to obtain the true bone matrix mass density in g cm^–3. Magn Reson Med 60:1433–1443, 2008. © 2008 Wiley‐Liss, Inc.     

Akute Blutdrucksteigerung – Nifedipin sublingual: kein unbedingter Reflex

Ohne Zusammenfassung     

Long-term follow-up of supra-annular pulmonary autograft aortic root replacement in patients with bicuspid aortic valve

Objective: The performance of the Ross procedure in the case of geometric mismatch between pulmonary autograft and a bicuspid aortic root has not yet been fully evaluated. To prevent geometrically caused autograft dysfunction, a modification of the surgical technique is necessary. Methods: Between January 1996 and January 2007, 50 patients (33 male, 17 female; mean age 50+/-14 years; range 13-63 years) underwent replacement of a diseased bicuspid aortic valve (stenosis in 14 cases; insufficiency in 21; combined disease in 15) with a Ross procedure. The pulmonary autograft was inserted partially in supra-annular position to correct the geometric mismatch between the deeper base of the non-coronary sinus and the right/left coronary sinus. In 24 of these patients, additional tailoring of the non-coronary sinus was necessary. In eight patients the non-coronary sinus was covered with a glutaraldehyde treated autologous pericardial patch to prevent pseudoaneurysm formation. Patients were followed up 1, 2, 5 and 10 years postoperatively. Results: There were no early or late deaths. There were six reoperations. One patient was reoperated because of persistent severe aortic valve insufficiency 9 months postoperatively. Three patients were reoperated for formation of subannular pseudoaneurysm, 6, 9 and 30 months postoperatively. One patient was reoperated for closure of a paravalvular dehiscence. Another patient was reoperated 1 year postoperatively because of a severe pulmonary stenosis due to excessive calcification of the bioprosthesis. Echocardiographic follow-up of the remaining patients showed no evidence of residual or recurrent pulmonary autograft regurgitation or progression of aortic root dilatation. Conclusion: Autograft replacement of the bicuspid aortic valve is challenging, as the geometric mismatch has to be adjusted. Valve dysfunction is avoided by a supra-annular implantation technique, but pseudoaneurysm formation at the base of the non-coronary sinus is a worrying aspect. Patch reinforcement may solve this issue.     

Minimally invasive versus conventional aortic valve replacement: a prospective randomized trial

BACKGROUND AND AIM OF THE STUDY: A prospective randomized study was performed to compare conventional with minimally invasive aortic valve replacement (AVR). METHODS: Forty consecutive patients scheduled for elective aortic valve surgery were prospectively randomized either to the conventional group (group A, complete median sternotomy) or minimally invasive group (group B, partial upper sternotomy). Intraoperative and postoperative clinical data, and markers of myocardial and cerebral protection were determined. Neuropsychological tests were carried out to quantify psychological disorders. RESULTS: Operative time and cardiopulmonary bypass time were slightly longer in group B, but not significantly so. No significant inter-group differences were found for postoperative pain scores and respiratory function. Chest tube drainage was significantly less in group B (495 +/- 165 versus 240 +/- 69 ml, p = 0.008). Creatine kinase (CK), CK-MB and troponin T levels were similar in both groups. Neither S-100B protein nor neuron-specific enolase levels differed significantly between groups at all sampling times. There were no strokes in the entire cohort. None of the neuropsychological tests yielded significant inter-group differences between conventional and minimally invasive surgery. CONCLUSION: The safety and reliability of AVR via a partial upper sternotomy is reported. Minimally invasive AVR can be performed with only slightly longer operative times, good cosmetic results and significantly less blood loss. A limited surgical access affected neither the patients' neurological outcome nor the efficacy of myocardial protection.