Stefan Schüler

Bio: Stefan Schüler is an academic researcher. The author has contributed to research in topics: Heart transplantation. The author has an hindex of 1, co-authored 1 publications receiving 17 citations.

Reliability of Tissue Doppler Wall Motion Monitoring After Heart Transplantation for Replacement of Invasive Routine Screenings by Optimally Timed Cardiac Biopsies and Catheterizations

Abstract: Background Invasive screenings at predefined time intervals for acute rejection and transplant coronary artery disease (TxCAD) are standard procedures. However, cardiac biopsies and catheterizations are distressing and risky for the patients and are also costly. We assessed the reliability of pulsed-wave tissue Doppler imaging (PW-TDI) for the timing of invasive examinations in heart recipients in an attempt to avoid unnecessary endomyocardial biopsies (EMBs) and catheterizations. Methods and results PW-TDI obtained at the basal left ventricular posterior wall before 408 EMBs and 293 catheterizations was tested for its diagnostic value regarding rejection and TxCAD with the use of International Society of Heart and Lung Transplantation biopsy grading, coronary angiography, and intravascular ultrasound as standards. Early diastolic peak wall motion velocity and relaxation time showed high sensitivities for clinically relevant rejection diagnosis (90.0% and 93.3%, respectively). The negative and positive predictive values for rejection of diastolic parameter changes appeared high enough (up to 96% and 92%, respectively) to allow a reliable noninvasive PW-TDI monitoring with efficiently timed, instead of routinely scheduled, EMBs. At definite cutoff values for systolic parameters, the probability for TxCAD reached 92% to 97%. The Fisher classification functions allowed TxCAD exclusion with 80% probability. Conclusions Without diastolic parameter changes, acute rejection can be practically excluded, and serial PW-TDI can save patients from routine EMBs. The high specificity and negative predictive value for TxCAD of reduced systolic peak velocities and extended systolic time allow optimized timed catheterizations. Peak systolic velocity and systolic time allow diagnostic classifications that enable patients without known TxCAD but with high risk for catheterization to be spared routine angiographies.

Plasmapheresis and cyclophosphamide in the treatment of humoral rejection after heart transplantation.

Abstract: Background: Clinical reports on humoral rejection after heart transplantation showed that these episodes were often more severe than those mediated through T lymphocytes and that the patient’s prognosis was significantly worsened. Methods To evaluate the impact of plasmapheresis on the course of humoral rejection with hemodynamic compromise (HRHC) episodes, we retrospectively investigated the records of 1,108 heart transplant patients. All patients received triple-drug immunosuppression (cyclosporine a, azathioprine, prednisone) and cytolytic antibodies for induction. Between April 1986 and December 1990, HRHC episodes were treated with cortisone boli and cytolytic antibodies for at least 3 days (Group A). Between January 1991 and April 1999, HRHC episodes were treated with cortisone boli, cytolytic antibodies, and plasmapheresis for at least 3 days (Group B). All patients who survived their first HRHC episode received cyclophosphamide instead of azathioprine as maintenance immunosuppression. Results Altogether we observed 29 HRHC episodes. In 11 cases, no therapy could be administered or the therapy regimen did not correspond to either Protocol A or B. In the remaining 18 HRHC episodes, 7 episodes in 7 patients were treated without plasmapheresis (Group A), but only 2 patients survived, whereas in 11 HRHC episodes in 6 patients, therapy included plasmapheresis (Group B) and all patients survived ( p = 0.002). Four of 6 patients who received cyclophosphamide after their first HRHC episode experienced at least 1 further HRHC episode. Conclusions Plasmapheresis seems to improve outcomes in HRHC. However, cyclophosphamide as a maintenance immunosuppressive drug failed to prevent further humoral rejection episodes.

Utility of left ventricular systolic torsion derived from 2-dimensional speckle-tracking echocardiography in monitoring acute cellular rejection in heart transplant recipients

Abstract: Background Reduced left ventricular torsion (LV-tor) has been reported to be associated with acute rejection in heart transplant (HTx) recipients. We investigated the utility of LV-tor analysis derived from 2-dimensional speckle-tracking echocardiography (2D-STE) for detecting allograft rejection. Methods A total of 301 endomyocardial biopsies (EMBs), right heart catheterizations and echocardiograms were performed in 32 HTx recipients. Echocardiography was done within 3 hours from EMB or simultaneously with the procedures. The LV-tor was defined as the difference between apical and basal end-systolic rotations. The LV-tor values with and without cellular rejection were compared. In addition, we investigated whether the change in LV-tor values predicts the change in rejection grade in each patient. The baseline LV-tor value in each patient was defined as a mean value of the first 3 LV-tor measurements obtained when the patient was free from rejection. Results According to the conventional International Society for Heart and Lung Transplantation criteria, 274 biopsies showed a rejection Grade of 0, 1a or 1b (Group AR − ), whereas 27 biopsies were Grade 2 or higher (Group AR + ). LV-tor decreased more in Group AR + than in Group AR − (9.3 ± 0.7 vs 12.2 ± 0.2 degrees, p Conclusion LV-tor derived from 2D-STE could be of clinical value for non-invasive monitoring of acute rejection in HTx recipients.