Long-term results of mechanical and biological heart valves in dialysis and non-dialysis patients.

INTRODUCTION: We wanted to answer the question whether biological heart valves are inferior compared to mechanical heart valves in end-stage renal disease (ESRD) patients. METHODS: Between 01/1996 und 12/2006, 44 of 3293 patients undergoing aortic valve replacement (AVR) in a single institution suffered from dialysis-dependent ESRD and underwent a follow-up investigation after 1.9 years (median). Twelve (28.9 %) of these patients received a biological, 32 (71.1 %) of these patients a mechanical aortic valve prosthesis. To evaluate a possible influence of the valve type (biological/mechanical) on survival, uni- and multivariate logistic regression was used. RESULTS: ESRD patients after AVR had a relatively poor short-term (30-day mortality: 22.7 %) and long-term survival (median survival time: 24.7 months; 95 % CI: 0.2-47.7 months), irrespective of the type of heart valve prosthesis (hazard ratio for mortality depending on heart valve type in dialysis patients: 1.31, P = 0.400). Dialysis-dependent patients were not reoperated due to valve-related reasons. CONCLUSIONS: The long-term survival of dialysis-dependent patients after AVR is low (5-year survival: 29.5 %) irrespective of the type of heart valve prosthesis. Therefore, the use of biological AVR is not contraindicated in this group of patients.

On-line variable live-adjusted displays with internal and external risk-adjusted mortalities. A valuable method for benchmarking and early detection of unfavourable trends in cardiac surgery.

OBJECTIVE: Benchmarking and early detection of unfavourable trends. METHODS: We implemented a dedicated project-orientated data warehouse, which continuously supplies data for on-line computing of the variable live-adjusted displays (VLADs). To calculate the expected cumulative mortality, we used the multi-variate logistic regression model of the EuroSCORE model. In addition to the external EuroSCORE standard, we calculated a centre-specific risk score for internal standards by analysing the data of 9135 patients, which enables both internal and external comparisons. The VLADs are embedded into the multi-purpose web-based information portal, so that the physicians can investigate several types of VLADs interactively: performance of different types of surgery and individual surgeons for different time intervals. We investigated clinically important events such as modification of operative techniques and personnel changes of the team by the VLADs. RESULTS: We found transient declines in the performance curves during major changes in patient management, indicating that systemic--rather than accidental or patient related factors--were involved in the mortality risk. The internal standard line represents these clusters more clearly than the external line. We evaluated examples of how periods of increased risk could be monitored by the VLAD curves: (1) the introduction of OPCAB surgery; (2) training of surgeons; (3) staff changes and staff-related management. CONCLUSIONS: On-line VLADs based on a day-to-day updated database, displaying both internal and external standards, are a helpful visualisation tool for earlier detection of unfavourable trends. They enable the surgeon teams and clinical management to take countermeasures at an early stage.

Is there any impact of the shape of aortic end-hole cannula on stroke occurrence? clinical evaluation of straight and bent-tip aortic cannulae.

OBJECTIVE: To compare the impact of straight and bent-tip aortic cannulae on stroke occurrence, location, and severity. METHODS: Prospective data were collected on 8,129 patients (coronary artery bypass grafting (CABG) and/or valvular surgery). 'Bent-tip' aortic cannulae were used in 15.6% of cases and 'straight' end-hole cannulae in 84.4% of cases. RESULTS: There were a total of 137 strokes: right anterior 52, left anterior 39, bilateral 23, posterior 18, and location not established 5. With the use of bent-tip cannulae, the incidence of strokes was 0.9% versus 1.8% with straight cannulae (chi2, p = 0.026). Bilateral and posterior strokes occurred more often with the use of straight cannulae (chi2, p = 0.015). Straight cannulae also related to the severity of strokes (chi2, p = 0.003). CONCLUSIONS: There is an influence of the type of cannula on the occurrence, location, and severity of strokes. Straight cannulae cause significantly more often and more severe bilateral and posterior strokes than bent-tip cannulae.

Mitral annular function assessed by 3D imaging for mitral valve surgery.

We developed a surgical technique for mitral valve reconstruction without a prosthetic ring. This procedure may have two advantages. One is avoidance of the potential thrombogenicity of the prosthetic ring, and the other is that this procedure may maintain the normal function of mitral annulus. To clarify the latter advantage, we defined a method for 3D assessment of the heart, especially for the dynamic changes of the mitral annulus. 3D images of the heart, including both mitral and tricuspid annuli in eight phases during the cardiac cycle, were reconstructed from magnetic resonance images of seven normal subjects, and used for this study. To depict the changes in the annular shape, we determined the following parameters of the annular function: (a) annular excursion, (b) direction of motion (direction cosine) and (c) orientation of the annulus (direction cosine) for the annular motion, (d) annular area and (e) displacement of the anterior portion from the approximated plane of the annulus. The data for the systolic annular motion indicate that the mitral annulus moves towards the apex with slight caudal deviation, with the excursion of 12.1 mm. The change in annular orientation indicates that the mitral annulus shows translational motion during systole. The mitral area was reduced by 25.6% (n = 5) from mid-diastole to mid-or late systole. Displacement at the anterior portion of the annulus did not change markedly during systole. The results demonstrate the physiologic function of the mitral annulus in normal subjects. This method will be applied to the clinical study of mitral valve reconstruction surgery. Based on the differences in annular length in intact and excised states, we describe the intact state of the posterior leaflet as "natural redundancy." Restoration of this natural redundancy has been a hallmark of successful mitral repair for over 20 years.