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Biomedical subjects

D Regensburger

Publications and source records attributed to D Regensburger.

At least 19 recordsLinked to original sources
PubMed2002

Bypass surgery versus stenting for the treatment of multivessel disease in patients with unstable angina compared with stable angina.

BACKGROUND: Earlier reports have shown that the outcome of balloon angioplasty or bypass surgery in unstable angina is less favorable than in stable angina. Recent improvements in percutaneous treatment (stent implantation) and bypass surgery (arterial grafts) warrant reevaluation of the relative merits of either technique in treatment of unstable angina. Methods and Results- Seven hundred fifty-five patients with stable angina were randomly assigned to coronary stenting (374) or bypass surgery (381), and 450 patients with unstable angina were randomly assigned to coronary stenting (226) or bypass surgery (224). All patients had multivessel disease considered to be equally treatable by either technique. Freedom from major adverse events, including death, myocardial infarction, and cerebrovascular events, at 1 year was not different in unstable patients (91.2% versus 88.9%) and stable patients (90.4% versus 92.6%) treated, respectively, with coronary stenting or bypass surgery. Freedom from repeat revascularization at 1 year was similar in unstable and stable angina treated with stenting (79.2% versus 78.9%) or bypass surgery (96.3% versus 96%) but was significantly higher in both unstable and stable patients treated with stenting (16.8% versus 16.9%) compared with bypass surgery (3.6% versus 3.5%). Neither the difference in costs between stented or bypassed stable or unstable angina ($2594 versus $3627) nor the cost-effectiveness was significantly different at 1 year. CONCLUSIONS: There was no difference in rates of death, myocardial infarction, and cerebrovascular event at 1 year in patients with unstable angina and multivessel disease treated with either stented angioplasty or bypass surgery compared with patients with stable angina. The rate of repeat revascularization of both unstable and stable angina was significantly higher in patients with stents.

Acute Disease↗
PubMed2002

Long-term results after surgical correction of atrioventricular septal defects.

OBJECTIVE: Review of the results of surgical correction of atrioventricular septal defects (AVSD), identification of risk factors for mortality and failure of left AV valve repair and determination of the impact of cleft closure on postoperative AV valve function. METHODS: Between 1975 and 1995, 121 consecutive patients (55 males, 66 females) underwent surgery for biventricular correction of AVSD with a median age of 1.2 years and a median weight of 7.6 kg. Sixty-five patients had a complete AVSD, 17 patients an intermediate type, and 39 patients a partial AVSD. The left AV valve (MV) cleft was closed in 53 patients (43.8%). The mean follow-up time is 7.2+/-4.6 years. RESULTS: Actuarial survival of the whole group after 1 year was 80%, after 10 and 20 years 78 and 65%, respectively. There were 18 early deaths (7-day mortality, 10.7%; 30-day mortality, 14.9%) and eight late deaths. In a univariate analysis, risk factors for early or late death were diagnosis of complete AVSD (P=0.006), no cleft closure (P=0.024), postoperative complications (P<0.0001), age <1.2 years (P=0.017), weight <7.6 kg (P=0.002), PA/Ao pressure ratio >0.7 (P<0.0001), and ECC time >110 min (P=0.002). In the multivariate analysis, postoperative complications (P=0.003) and PA/Ao pressure ratio >0.7 (P=0.001) had parallel effects on the postoperative risk for mortality. Moderate or severe MV regurgitation was present in six patients (6.0%) in the first evaluation after discharge and in 20 patients (20.4%) in the most recent postoperative control. There were 25 reoperations in 17 patients, of which 15 had to be performed for MV regurgitation and two for MV stenosis. Freedom from reoperation was 91% at 1 year, 79% at 10 years, and 76% at 15 and 20 years. We could not identify a statistically significant risk factor for reoperation. CONCLUSIONS: In patients with AVSD of various morphologies closure of the left AV valve cleft significantly improves outcome without affecting the need for reoperation. Risk factors for early and late death (multivariate analysis) were a pulmonary/aortic pressure ratio >0.7 and the occurrence of any complication after surgery. The concept of an early surgical AVSD correction before an increase in pulmonary vascular resistance and AV valve deformations occur would represent a better surgical option than a late correction as done in our series. Early correction allows for reduction of early mortality, superior long-term survival rates and a high freedom from subsequent valve degeneration.

Actuarial Analysis↗
PubMed2001

Correction of tetralogy of Fallot: does the time period of surgery influence the outcome?

BACKGROUND: The perioperative outcome of patients with tetralogy of Fallot (TOF) seems to have improved over the last four decades. METHODS: To prove this hypothesis, we retrospectively analysed the data of 269 TOF patients operated on between 1975 and 1999 in our institution. RESULTS: Over the years, younger patients (median age 1975 - 1980: 4.5 years, 1995 - 1999: 0.9 years) were operated on with a lower mortality (1975 - 1980: 8.6 %, 1995 - 1999: 2.4 %). Residual defects such as pulmonary stenosis or insufficiency and VSD occurred with a similar frequency over time, whereas rhythm disturbances were significantly reduced (1981 - 1985: 51.2 %, 1995 - 1999: 24.4 %, p = 0.012). Postoperative length of hospital stay was significantly (p < 0.05) shorter in the years 1995 - 1999 (11.0 - 11.4 days) than in 1975 - 1980 (16.9 +/- 16.5 days). CONCLUSIONS: Over time periods, there was a trend towards lower mortality and towards operating on patients in a younger age. The rate of rhythm disturbances and the LOS after surgery proved to be reduced during the last decade. These differences did not turn out to be statistically significant. Therefore, we conclude that the time period of surgery has only little impact on the early outcome of patients after definitive correction of TOF.

Age Factors↗
PubMed2001

Tetralogy of Fallot: influence of surgical technique on survival and reoperation rate.

BACKGROUND: The influence of different surgical techniques in patients with Tetralogy of Fallot (TOF) on long-term survival and reoperation rate is still a matter of controversy. PATIENTS AND METHODS: The data of 266 patients (152 male, 114 female, mean body weight: 13.4 +/- 11.9 kg, mean age 4.1 +/- 6.0 years) with TOF, including 30 patients (11.2 %) with TOF/pulmonary atresia, were analyzed retrospectively. A palliative surgical procedure preceded definite correction between 1975 and 1999 in 46 patients (17.5 %). The surgical technique consisted of a transannular patch in 103 patients (40.1 %); in 133 patients (51.8 %), a non-transvalvular technique was used. In 33 patients (12.3 %), a conduit was implanted into the right ventricular outflow tract (RVOT). For surgical access to the cardiac defects, a transventricular approach was used in 138 patients, and a transatrial/trans-pulmonary approach in 26 patients. The mean follow-up time of all patients was 6.6 years. RESULTS: Kaplan-Meier survival for the entire group was 86.2 % at one year and remained stable at 85.6 % after 5 years. The 30-day mortality was 10.1 % (27 patients). Fatal risk factors were: previous cardiac surgery, preoperative oxygen saturation (SO(2)) < 80 %, diagnosis of pulmonary atresia, prolonged aortic clamping or bypass time, postoperative infections, and early revisions. Freedom from reoperation was 91.6 % after 5, 84.5 % after 10, and 52.6 % after 20 years. There was no correlation between the different surgical techniques (transannular patch, non-transvalvular techniques, transventricular approach) applied and the mortality or the rate of reoperations. CONCLUSIONS: In our series of TOF patients operated over a period of 25 years, we were unable to assess an influence of the surgical technique used for definite correction on mortality or reoperation rate. Pulmonary atresia in patients with TOF is associated with a higher risk of death and reoperation.

Adolescent↗
PubMed2001

Early clinical experience with the On-X prosthetic heart valve.

BACKGROUND AND AIM OF THE STUDY: The study was designed to investigate the clinical performance of the On-X prosthetic heart valve in a multicenter experience. METHODS: Between September 1996 and September 1999, 301 patients (56% males) underwent isolated On-X valve replacement (184 isolated aortic (AVR), 117 isolated mitral (MVR)) at 11 European centers under a standardized protocol. Average age at implant was 60.2 years. Office or hospital follow up was required by the protocol; average follow up on all patients was 11 months. RESULTS: Thirty-day mortality in the study was 2.2% for AVR and 6.0% for MVR, with valve-related mortality of 0.5% for AVR. There were eight late deaths (0.7%/pt-yr AVR and 2.3%/pt-yr MVR). Two of these deaths were sudden, and thus possibly valve-related (one AVR, one MVR). Early total valve-related morbidity was 3.5% for AVR and 2.6% for MVR. In total, 13 thromboembolic events occurred; one early event in AVR resulted in death (0.5%), and one transient early event occurred in MVR (0.9%). There were 11 late events (seven AVR (1.7%/pt-yr) and four MVR (1.8%/pt-yr)), for a two-year freedom from thromboembolism of 96.6% after AVR and 97.1% after MVR. Three late bleeding events occurred, all after AVR (0.7%/pt-yr and 98.9% free at two years). Major paravalvular leaks requiring reoperation occurred on two occasions early (one AVR (0.5%), one MVR (0.8%)) and once late in MVR (0.5%/pt-yr). Late minor, untreated paravalvular leaks occurred in three AVR patients (0.7%/pt-yr) and in one MVR patient (0.5%/pt-yr). Prosthetic endocarditis occurred four times (two AVR (0.5%/pt-yr), two MVR (0.9%/pt-yr)), all within the first 12 months of surgery. Actuarial freedom from all valve-related events at two years was 88.7% for AVR and 88.1% for MVR. NYHA class was improved in 75.8% of AVR patients and 70.6% of MVR patients at two years after surgery. CONCLUSION: These early results indicate that the On-X valve provides satisfactory clinical outcome in the immediate postoperative period, and that the valve is both safe and effective.

Actuarial Analysis↗
PubMed2000

Examination of hemolytic potential with the On-X(R) prosthetic heart valve.

BACKGROUND AND AIM OF THE STUDY: Mechanical valves are known to produce chronic, subclinical hemolysis in most patients. Generally, haptoglobin is reduced to below normal in most patients, while lactate dehydrogenase (LDH) is increased to as much as 200% above the upper normal, sometimes resulting in anemia. The study was designed to investigate the clinical hemolysis of the On-X(R) prosthetic heart valve in a multicenter experience with a standard protocol and a single clinical laboratory. METHODS: Between September 1996 and August 1998, 248 patients underwent isolated valve replacement at 10 European centers. Blood samples were collected from these preoperatively and at 3-6 months and one year postoperatively. All samples were analyzed at a central laboratory, thus assuring poolability of the data. In total, 151 patients were tested at 3-6 months, and 62 at one year. Blood parameters measured were LDH, haptoglobin, hematocrit, total hemoglobin, red cell count and reticulocyte count. Paired analysis was used to compare preoperative baseline values with 3-6-month and one-year values. Data were analyzed with regard to both valve position and size. RESULTS: At 3-6 months and one year after surgery, average values for hematocrit, hemoglobin, red cell count and reticulocyte count were all near the center of the normal range, regardless of valve position or size. Statistically significant increases in red cell count and decreases in reticulocyte count occurred after both aortic valve replacement (AVR) and mitral valve replacement (MVR). These changes were of no clinical importance, but indicate that anemia has not occurred in these patients. At 3-6 months, haptoglobin was reduced to below normal in 86% of both AVR and MVR patients; this also occurred after one year and was statistically significant. Postoperatively, the mean LDH value in AVR was 228 U/l (91% of upper normal, 250 U/l) at 3-6 months, and 246 U/l (98% of upper normal) at one year. In MVR, these LDH values were 271 U/l (108% of upper normal) and 265 U/l (106% of upper normal). CONCLUSIONS: These results indicate that the On-X valve causes lower levels of chronic hemolysis in the immediate postoperative period and up to one year after surgery, especially when compared with reports of LDH elevations up to 200% of upper normal. Hemolytic anemia has not occurred in this patient population.

Aortic Valve↗
PubMed1998

Gene transfer into rat heart-derived endothelial cells.

OBJECTIVE: Progressive graft arteriosclerosis is responsible for the majority of late deaths in cardiac transplant recipients. Despite many investigations, the pathogenesis of this disease remains undetermined and its control inadequate. A somatic gene transfer during the cold ischemic time and thus before transplantation might be a new therapeutic tool. This approach allows a long incubation time of the DNA and a safe transfer with liposomes and transferrin with less adverse effects for the organ recipient. METHODS: The target cells (microvascular endothelial cells (MVECs)) for this gene transfer were isolated from rat hearts by perfusion with collagenase via an aortic cannulae. The cells were purified by changing the medium 30 min after subcultivation in order to remove fibroblasts and smooth muscle cells. The endothelial cells (ECs) were identified by typical morphology and the uptake of Dil-Ac-LDL. The gene transfer was carried out with a beta-galactosidase reporter plasmid (pCMVbeta), cationic liposomes (Lipofectin), and transferrin. Different transfection solutions were prepared with or without serum, and with different plasmid-liposome ratios and transferrin concentrations. The transfer rate was monitored with a semiquantitative orthonitrophenyl-beta/-D-galactoside (ONPG) assay and histologically by X-Gal staining. The cytotoxicity of this procedure was determined with a colorimetric ELISA with Alamar blue. The cardioplegic property of the transfection solution was tested in a Langendorff perfusion system monitoring the coronary blood flow over time after a cold ischemic time of 4 h. RESULTS: The maximal gene expression could be detected after transfection with 4 microl Lipofectin, 2 microg pCMVbeta, and 16 microg transferrin/200 microl transfection solution. Under these conditions 60% of the cells showed a blue staining with X-Gal. Only 20% of the cells died during transfection. The lowest cytotoxicity during cold ischemic time for ECs was assessed with normal cell culture medium and the Buckberg solution. The best coronary flow rates after 4 h cold ischemia of the heart were measured for cardioplegia with St. Thomas and Buckberg solutions. In summary, the best transfection solution with a good cardioplegic property was the Buckberg solution. CONCLUSIONS: Finally, the results of this study show that an effective DNA delivery with a low toxicity into ECs is possible with a combination of liposomes and transferrin. This method might be useful for a safe and effective gene transfer into solid organs during the cold ischemic time and thus a therapeutic tool for chronic rejection.

Animals↗
PubMed1997

[Minimal invasive therapy of aneurysms of the superficial femoral artery and the popliteal artery].

Percutaneous stent placement has been described for treatment of aneurysms as an alternative to surgical therapy. Literature reports of percutaneous minimal invasive therapy of peripheral aneurysms shall be reviewed and compared with our own results. Six male patients (51-69 years) with femoropopliteal occlusions related to aneurysms were treated percutaneously. In two cases Wallstents and in four cases polyester-covered nitinol stents were applicated. A clinical investigation including doppler-ultrasound was performed 24 hrs, 1, 3, 6, 12 and 24 months after the intervention. Stent placement succeeded in all cases. No adjunctive surgical treatment was necessary. Ankle-brachial-index (ABI) improved from 0.22 +/- 0.2 before to 0.74 +/- 0.2 24 hours after the intervention. One patient was lost for follow-up (Wallstent). A decrease of ABI and additional intraarterial angiography revealed stent-graft occlusion within one month (n = 2) and within three months (n = 1). One of these cases was successfully recanalized with local fibrinolysis therapy. In three patients patency of the stent persisted for 24 (+/- 2) months follow-up with three-vessel-supply of the calf. These results warrant further investigations for this minimal invasive method of percutaneous stent deployment as an alternative to surgical bypass treatment of femoropopliteal aneurysms. Time of hospitalization was reduced. At this time, surgical treatment of peripheral vascular aneurysms is gold standard.

Aged↗
PubMed1996

Effects of enoximone on right-ventricular function in patients with impaired myocardial performance.

The effects of an enoximone monotherapy on left-ventricular and especially on right-ventricular haemodynamics were investigated in fourteen patients with impaired left-ventricular function secondary to coronary artery disease. Anaesthesia was induced and maintained with fentanyl and flunitrazepam. After reaching steady state, a bolus of 0.5 mg/kg enoximone was administered, followed by an infusion of 0.5 microgram/kg/min. Besides the common haemodynamic parameters particulary the right-ventricular ejection fraction (RVEF) was measured using a special thermodilution technique. The predefined time points were: before administration of enoximone (baseline) and 5 min, 10 min, 15 min, 20 min, and 30 min after bolus injection of enoximone. Compared to the baseline the maximum effects of enoximone were a 28% increase of cardiac index accompanied by a 39% decline of systemic vascular resistance and an unchanged left-ventricular stroke-work index. While central venous pressure and mean pulmonary artery pressure remained unchanged. RVEF (+20%) and right-ventricular stroke-work index (+30%) were significantly augmented, augmented, indicating improved right-ventricular performance. No adverse effects of the enoximone administration were observed perioperatively. We conclude that an enoximone monotherapy is beneficial for patients with impaired myocardial function undergoing cardiac surgery.

Adult↗
PubMed1996

[Modified manual rt-PA pulse-spray lysis in occlusions of leg arteries and femoro-popliteal bypasses].

PURPOSE: The evaluation of local rt-PA pulse-spray-lysis (PSL) by the Katzen infusion wire for treatment of thrombosed leg arteries and bypass grafts. MATERIAL AND METHOD: 21 patients (mean age 64.4 years) with either occluded leg arteries (n = 19) or femorocrural bypass grafts (n = 2) were treated with PSL. Mean length of occlusion was 13.2 +/- 11.6 cm. Time of occlusion ranged from less than one week to 6 months. RESULTS: In 71.43% (15/21) the occlusions could be successfully recanalized with PSL. The mean rt-PA dose was 10.7 +/- 4.9 mg. Remaining stenoses were handled with PTA (n = 9) and additional stent implantation (n = 3). Additional long-time-lysis with 17.5 mg rt-PA was necessary in two cases, the success rate increased to 81% (17/21). The anlde-brachial-index increased from 0.38 +/- 0.29 to 0.83 +/- 0.32 within 24 hours after intervention. In 4 cases bleeding complications occurred. 5 patients showed reocclusions during 6 months follow-up. CONCLUSIONS: Local fibrinolysis with rt-PA in PSL technique using the Katzen infusion wire is a feasible and promising treatment of thrombosed leg arteries and grafts. Even careful and dosage-minimized rt-PA application cannot prevent bleeding complications.

Adult↗
PubMed1996

Multiple organ manifestations in thromboangiitis obliterans (Buerger's disease). A case report.

Thromboangiitis obliterans (TAO) occurs almost exclusively in young male smokers. Its involvement of the small and medium-sized arteries and veins leads to ischemic complaints and/or changes in the extremities. The possibility of organ involvement is a matter of controversy. The authors report a case of TAO with multiple organ involvement, including myocardial, splenic, and cerebral infarctions; pulmonary embolisms; and probable intestinal ischemia during a twenty-three-year course.

Adult↗
PubMed1995

[Prevention and therapy of prosthesis infections in the thoracic area].

Infections of vascular prostheses following replacement of the thoracic aorta remain a rare complication, fortunately. The incidence of prosthetic infection amounts to approximately 1.6%, however, there is only limited information from single center studies, and linearized actuarial data for more exact estimations are not available. Experience with prophylaxis and treatment of bacterial endocarditis as well as data available from peripheral vascular reconstruction nevertheless allow the development of treatment strategies concerning this complication. Experimentally, there is clear evidence that pretreatment of Dacron-grafts using the fibrin sealant-antibiotic compound results in a significant protection from infection, created by artificial contamination with staphylococcus aureus. This concept could clearly be confirmed in clinical series involving treatment of prosthetic valve endocarditis. Currently, the concept of implantation of cryopreserved human vascular allografts is studied clinically. Its efficiency in infected areas and following prosthetic replacement of the thoracic aorta has not been proven. Some preliminary results as well as studies on treatment for bacterial endocarditis would suggest a clear advantage of this strategy, however statistically significant improvements have not been published. Currently available data, however, appear to be sufficient to advocate potentially successful techniques as a prophylaxis in routine thoracic aortic replacement as well as for treatment in case of a vascular prosthetic infection following such procedures.

Animals↗
PubMed1992

[An aortopulmonary shunt after a knife wound].

An extensive hemopneumothorax developed in a 23-year-old man after having been knifed in the region of the left nipple. After general surgical care a Bülau suction drain was inserted. Cardiological examination became necessary a week later when a chest X-ray film demonstrated an enlarged cardiac silhouette. Echocardiography revealed pericardial effusion (about 600 ml) which was removed by pericardial aspiration. Cross-sectional and colour Doppler echocardiography showed a shunt between the aorta and right ventricular outflow tract at the origin of the pulmonary artery. At surgery a fistula between the root of the aorta and the pulmonary artery was identified (the posterior sinus near the anulus was nearly completely detached). The fistula was closed and the pulmonary valve reconstructed. The early and late postoperative course was unremarkable.

Adult↗
PubMed1992

Preoperative and late postoperative psychosocial state following coronary artery bypass surgery.

In a prospective study of psychological and neurological reactions to coronary artery bypass surgery, 45 patients were examined preoperatively, postoperatively, and 21 to 27 months after, using a variety of neurological, psychiatric, and psychological investigations. Within the follow-up sample, three subgroups of patients could be identified by cluster analysis who differed with respect to their emotional status and life satisfaction. One group (24% of the total sample) was characterized by high levels of anxiety, depression and life dissatisfaction and appears as a risk population. The other groups could be described as either average (42%) or stable (33%). At the follow up, the risk group further indicated a preference for depressive coping styles, a slightly higher degree of cognitive impairment, more neurological and psychopathological symptoms (specifically giving-up and hostility), a considerably lower return-to-work rate, more subjective physical complaints and a poorer attitude toward the outcome. While postoperative measurements (obtained 2-3 and 6-8 days after surgery) as well as intraoperative parameters did not reveal significant group differences, the analysis yielded an increased impairment within the risk group already prior to surgery, especially emotional problems, specific health-related cognitions and a more fatalistic attitude. The results are in line with those of other studies investigating the late postoperative psychological status with regard to the proportion of patients showing psychological impairments as well as to their specific psychological characteristics.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Psychological↗
PubMed1992

Truncus arteriosus communis associated with interrupted aortic arch: a report on two uncommon cases.

The paper presents two infants with the A-4 type of truncus arteriosus communis (according to Van Praagh's classification). One patient who survived a surgical procedure demonstrated a rare variant of aortic arch interruption to the left off the left subclavian artery (type A according to Celoria and Patton), whereas the second presented an uncommon anomaly in which the right subclavian artery originated from the descending aorta with associated severe truncal valve incompetency. The authors describe the clinical picture along with the surgical treatment of the first infant who being six days old was subjected to a correction employing the wide patent ductus arteriosus to reconstruct the aortic arch, following the method described by Gomes and McGoon. Subsequently an aortic homograft was implanted in order to connect the right ventricle and the pulmonary artery.

Aortic Arch Syndromes↗
PubMed1991

[Traumatic aortic rupture: immediate surgery--interval operation?].

On the basis of our own patient population of the last 12 years which involved 17 traumatic ruptures of the descending thoracic aorta in the isthmus area (preoperative hospital mortality at the time of diagnosis: 5.8%; surgical mortality: 27%; postoperative hospital mortality: 18.7%) the problems of assessing indications for surgical intervention in polytraumatized patients with aortic damage are discussed. The indications for "immediate surgery", for "surgery with delayed urgency", and for "surgery in the interval" are clearly defined.

Adolescent↗
PubMed1990

Early neurological abnormalities following coronary artery bypass surgery. A prospective study.

A prospective analysis of 78 patients undergoing coronary artery bypass surgery (CABS) was carried out to assess clinically the frequency and course of cerebral complications during the 1st postoperative week. Detailed evaluation of the patients showed that neurological abnormalities after CABS were common, occurring in 40 of the 78 patients (51%). However, there were no serious cerebral complications. Changes in reflexes and new focal signs were found in 26 and 25 cases respectively; in 7 patients (9%) they were confined to the first postoperative days. There was no statistically significant correlation between postoperative outcome and age, preoperative neurological state or bypass time. However, some strong associations could be calculated between a history of cerebrovascular signs or symptoms and the appearance of persisting focal signs or development reflexes during the 1st week after CABS.

Adult↗