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Biomedical subjects

H Oelert

Publications and source records attributed to H Oelert.

At least 55 records · Page 3Linked to original sources
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↗
PubMed2000

Complete atrioventricular septal defect associated with tetralogy of Fallot. Favourable outcome of transatrial transpulmonary repair.

BACKGROUND: Complete correction of atrioventricular septal defect (AVSD) associated with tetralogy of Fallot (TOF) has been reported to account for an increased surgical risk. Impaired right ventricular function after classic transventricular repair, residual outflow tract stenosis, and incompetence of the pulmonary or atrioventricular valves are considered to be essential factors affecting the results. METHODS: From 3/95 to 6/98 six consecutive patients with AVSD and TOF underwent repair (age 18 months to 7.3 years) using a combined transatrial-transpulmonary approach. RV outflow tract balloon dilatation preceded transatrial correction in 4 patients. Pulmonary annulotomy but not transanular patching was necessary in 4 cases. The septal defects were closed by two separate patches using a Dacron patch with short depth and anterior extension for the ventricular component. RESULTS: All patients survived and had stable sinus rhythm. Echocardiography demonstrated mild, but hemodynamically insignificant mitral regurgitation in two and tricuspid regurgitation in four patients. Right ventricle to pulmonary artery gradients ranged from 5 to 35 mmHg (mean 24.2 mmHg) without progression. During follow-up ranging from 4 months to 3.5 years (mean 16.8 months) no reoperation was necessary. CONCLUSIONS: The transatrial-transpulmonary approach for correction of AVSD with TOF contributes to improved results after repair of this rare combination of defects.

Child↗
PubMed1999

[Surgical treatment of hypoplastic left heart syndrome: experience with staged palliative reconstruction].

Hypoplastic left heart syndrome (HLHS) represents an anatomical spectrum of congenital disease with varying degrees of underdevelopment of the left-sided cardiac structures (Figure 1). The outlook for children born with HLHS, an otherwise highly lethal malformation, has improved with increasing experience with reconstructive techniques. This report represents a detailed analysis of the overall risk and mid-term results for a group of 39 consecutive neonates with HLHS referred to our hospital over a 5-year period between January 1994 and November 1998. Twenty-six patients were treated with a Norwood reconstructive procedure (Figure 2). One patient received a cardiac transplant at the request of the parents. Another patient with aortic atresia, ventricular septal defect and normal left ventricle underwent biventricular repair. Eleven patients were not eligible for surgical treatment due to a number of reasons (Table 1). In 26 neonates (9 girls, 17 boys; mean age 9.1 [4 to 42] days) staged reconstruction by Norwood's procedure was performed. The hospital mortality in the first stage of the Norwood procedure was 23% (6/26). Sixteen of the 20 long-term survivors underwent the bidirectional cavopulmonary anastomosis (hemi-Fontan; Figure 3) at a median age of 7.6 (3 to 14) months. All children survived. Up to now, 3 infants received the complete Fontan operation (Figure 4) at 2 years of age. No late death occurred. In 18 out of the 20 survivors neuro-developmental outcome and exercise performance were within the range of normals. Staged surgical palliation represents a realistic therapeutic option for neonates born with HLHS. At this intermediate stage of follow-up exercise performance and quality of life are satisfactory.

Child, Preschool↗
PubMed1999

[In Process Citation]

Intimal sarcoma of the pulmonary artery is an extremely rare type of malignant tumor of the large vessels. Despite systematic diagnostics, distinguishing between pulmonary emboli and tumors is difficult. We report a patient who was referred because of suspected embolic occlusion of the pulmonary artery. The operation was started with the intention of performing a pulmonary artery thromboendarterectomy; however, intraoperative histology revealed a malignant mesenchymal tumor. Therefore, the left lung was resected with the use of extracorporeal circulation, and the pulmonary trunk and right pulmonary artery were reconstructed. A solitary right lung metastasis was resected 3 months later using stapling devices. Complete surgical resection is the treatment of choice for patients with sarcoma of the pulmonary arteries. Surgical therapy often includes extensive reconstructive measures. Since, thromboembolic obstruction cannot be excluded preoperatively, patients with this type of disease should be treated at centers experienced with the broad spectrum of pulmonary artery surgery.

Journal Article↗
PubMed1999

[Diagnosis of an intramyocardial hematoma via MRI after a traumatic myocardial infarct].

Traumatic cardiac lesions occur in about 30% of all traumatized patients, in most cases they are due to traffic accidents. We report a patient who suffered from a traumatic anterior wall infarction following a ski accident. Consecutively, an extended intramyocardial hemorrhage occurred. A left ventricular pseudoaneurysm was considered first by echocardiography. Using MRI, an intramyocaridal hemorrhage could be diagnosed because of a thin myocardial border surrounding the hematoma. Consecutively, the patient underwent CABG surgery as well as a resection of the intramyocardial hematoma. This diagnosis could be manifested surgically and histologically.

Aged↗
PubMed1999

[Quantitative detection of changes in the thoracic aorta in patients with chronic aortic dissection using transesophageal echocardiography].

The aim of this serial 3 year follow-up study in 42 clinically stable patients with chronic aortic dissection was to assess quantitatively morphologic changes of the descending thoracic aorta (AD) using transesophageal echocardiography (TEE). Communicating dissections (ca) were present in 16/19 patients with operated type I and in 11/23 patients with type III AD whereas 12/23 type III AD according to De Bakey were non-communicating (nc). Diametral enlargement of the disc. thoracic aorta was 4 mm (mean value) at 1 year in all patients, 5.9 mm in type I ca, 7.2 mm in type III ca but only 3.1 mm in type III nc at 3 years. The ratio between true lumen and false lumen (FL) changed in ca AD from 1:2 to 1:3 over the period of 3 years but remained constant at 1:1 in ncAD. Progressive thrombosis of the false lumen (FL) occurred in 76% of patients but complete thrombosis of the FL occurred in only 6% of type I ca, 18% type III ca but in 84% of type III nc patients. Our results confirm observations that non-communicating dissections seem to have a more favorable outcome and less aneurysmal dilatation compared to ca dissection.

Adult↗
PubMed1999

Reduced inotropic support after aprotinin therapy during pediatric cardiac operations.

BACKGROUND: Several reports indicate that aprotinin treatment before and during cardiopulmonary bypass (CPB) might have a protective effect on the myocardium. We evaluated the hemodynamic effects of perioperative aprotinin treatment. METHODS: We conducted a randomized, double-blind, placebo-controlled trial in 34 infants (mean age, 2.5 years) who had cardiac operations. Half of the patients received high-dose aprotinin therapy. There were no significant differences between the aprotinin and placebo groups with respect to age, weight, sex, aortic cross-clamp time, and CPB time. The following data were recorded at arrival in the intensive care unit 6, 12, 24, and 48 hours after termination of CPB: heart rate, blood pressure, left atrial pressure, central-peripheral temperature difference, arterial-central venous oxygen saturation difference, urine output, serum creatinine, lactate and neutrophil elastase levels, the Doppler echocardiographic factors shortening fraction and preejection period/left-ventricular ejection time, and cumulative doses of catecholamines (epinephrine), enoximone, and furosemide. RESULTS: No hemodynamic variable showed any significant difference between aprotinin and placebo groups. Urine output, creatinine, lactate, and elastase levels, as well as the cumulative doses of furosemide and epinephrine were not significantly different. Twelve hours after CPB 10 patients in the placebo group and 4 in the aprotinin group had received enoximone (p<0.05). The placebo group had received significantly larger doses of enoximone than the aprotinin group at arrival in the intensive care unit (0.13+/-0.05 versus 0 mg/kg), 12 hours after CPB (0.58+/-0.14 versus 0.18+/-0.09 mg/kg), 24 hours after CPB (1.11+/-0.24 versus 0.42+/-0.16 mg/kg), and 48 hours after CPB (1.61+/-0.40 versus 0.86+/-0.28). At 6 hours the difference did not reach statistical significance. CONCLUSIONS: Clinical and hemodynamic status of the aprotinin-treated patients was similar to that of the placebo-treated patients in the first 48 hours after CPB. The placebo group, however, required significantly more inotropic support by enoximone than the aprotinin group to achieve this goal.

Adolescent↗
PubMed1999

Cardiac pacing in premature infants and neonates: steroid eluting leads and automatic output adaptation.

BACKGROUND: Appropriate generator and lead selection as well as techniques of implantation are most important aspects of cardiac pacing in the extremely young patient. Here we report the clinical results using a new technique with automatic output adaptation based on evoked response in combination with steroid-eluting epicardial leads in small children. METHODS: One neonate and 2 premature infants underwent permanent pacemaker implantation because of congenital high-degree atrioventricular block or postoperative complete heart block, respectively. Steroid-eluting epicardial leads and a multiprogrammable pacemaker with automatic output adaptation were used. RESULTS: Intermuscular abdominal generator placement and epicardial suture-fixation of the bipolar lead through a subcostal approach was without complications. Serial follow-up examinations revealed safe and consistent pacemaker function up to 12 months after operation. CONCLUSIONS: The technique represents an excellent alternative for permanent cardiac pacing in extremely small patients. We believe that it provides an increase in functional lifetime of the devices and delays the need for battery replacement with its associated complications in this young patient population.

Algorithms↗
PubMed1999

Adjustable tourniquet to manipulate pulmonary blood flow after Norwood operations.

BACKGROUND: Survival after first-stage palliative Norwood operations for single ventricle with systemic outflow obstruction is mainly dependent on a balanced ratio of pulmonary blood flow to systemic blood flow. Here we report the clinical results using a modified technique that allows a controlled systemic-to-pulmonary shunt flow to prevent pulmonary overcirculation. METHODS: From 1995 to 1998, of 26 infants undergoing first-stage palliative Norwood operations, 7 had placement of an adjustable tourniquet around a modified right Blalock-Taussig shunt. RESULTS: Hospital survival was 20 of 26 patients (77%). All 7 patients in whom snaring of the shunt was indicated survived. Two patients underwent repeated adjustment, in 5 patients the tourniquet could be removed during delayed sternal closure, and 2 patients were discharged with the shunt partially snared. CONCLUSIONS: The snare-controlled systemic-to-pulmonary shunt allows improved hemodynamic stability after reconstructive surgery for hypoplastic left heart syndrome or other similar complex cardiac defects by reducing the risk of pulmonary overcirculation. It is simple and rapidly executed. The option of graded banding of the shunt depending on the hemodynamic situation increases flexibility and safety after cardiopulmonary bypass or at any time in the postoperative period.

Cardiac Surgical Procedures↗
PubMed1999

Long-term results after thromboendarterectomy for chronic pulmonary embolism.

OBJECTIVE: In patients with chronic thromboembolic pulmonary hypertension, pulmonary vascular resistance (PVR) can be reduced by pulmonary thromboendarterectomy (PTE). In this study, long-term symptomatic and hemodynamic effects were investigated. METHODS: Twenty-two patients (12 female, 10 male, mean age 40 years, preoperative NYHA functional class II/III/IV: n = 1/12/9) were re-evaluated 48-72 months (mean 60 months) after surgery. In addition to clinical assessment, radiologic, hemodynamic and echocardiographic investigations were performed. RESULTS: All patients reported a marked improvement of their clinical condition. At follow-up, 11 patients were identified as NYHA class I, 10 as NYHA class II and one patient was in class III. PVR and mean pulmonary artery pressure (mPAP) were significantly reduced (preoperative PVR 800+/-274 dynes/s per cm(-5), follow-up PVR 180+/-28.3 dynes/s per cm(-5); P < 0.001; preoperative mPAP 48.5+/-7.4 mmHg, follow-up mPAP 27.5+/-4.9 mmHg; P < 0.001). There was also a significant increase in arterial blood oxygen tension (preoperative PaO2 59+/-10 mmHg; follow-up PaO2 84+/-12 mmHg; P < 0.001). Chest roentgenograms and echocardiographic examinations revealed significantly decreased right heart dimensions and a recovery of right heart function. CONCLUSION: In patients with severe chronic thromboembolic pulmonary hypertension, persistent symptomatic and hemodynamic improvements can be achieved by PTE.

Adult↗
PubMed1998

[Increased acceptance of the International Normalized Ratio (INR) as a monitoring parameter of oral anticoagulation therapy in Germany. GELIA Study Group].

In 1994 the German Cardiac Society recommended the International Normalized Ratio (INR) instead of "Quick's test" for the long-term management of oral anticoagulation therapy. Parallel cardiac surgical centers in Germany and Switzerland started patient recruitment for the GELIA study (German Experience with Low Intensity Anticoagulation). By the end of 1996, 862 consecutive patients with mechanical heart valve replacement had been enrolled. According to the protocol of the GELIA study, intensity of anticoagulation, methods used to control the oral anticoagulation therapy as well as other factors relevant for the anticoagulation management are reported every three months. The so far accumulated data material of the GELIA study seemed, therefore, appropriate to analyze potential changes in the acceptance of INR during the time period 1993-1996. Potential differences in the anticoagulation management were analyzed separately according to the time of enrollment of patients and changes during the follow up period, e. g., a switch from "Quick's test" to INR. Taking the time of enrollment into account, the percentage of patients who had INR-controlled oral anticoagulation therapy increased from 0% (1993), 14.3% (1994), 63.2% (1995) to 74.2% in 1996. During the follow up, there was a change from "Quick's test" to INR controls in 7 patients (1994; 2.1%), 67 patients (1995; 10.5%) and 142 patients (1996; 17.3%) with a consequent increase of INR controlled patients to a total of 34.2% in 1994, 52.0% in 1995, and 73.9% in 1996.

Administration, Oral↗
PubMed1998

High-dose epsilon-aminocaproic acid versus aprotinin: antifibrinolytic efficacy in first-time coronary operations.

BACKGROUND: The antifibrinolytic efficacy of a high-dose regimen of epsilon-aminocaproic acid (epsilon-ACA) was compared with aprotinin in first-time coronary operations. METHODS: In a prospective, double-blinded, randomized study, 20 patients received high-dose epsilon-ACA (10 g both as a loading and cardiopulmonary bypass priming dose, 2.5 g/h until 4 hours after protamine), and another 20 patients received aprotinin (2 x 10(6) KIU [280 mg] for loading and priming, 0.5 x 10(6) KIU/h [70 mg/h]). Ten untreated patients served as controls. RESULTS: Both agents reduced postoperative levels of thrombin/antithrombin III complexes, D-dimers, fibrin degradation products, free plasma hemoglobin (epsilon-ACA versus aprotinin, p = not significant; p < 0.05 versus controls), and amount of retransfused autologous blood (p < 0.001). Epsilon-ACA increased, aprotinin suppressed antiplasmin-plasmin complex generation (epsilon-ACA versus controls, p < 0.02; epsilon-ACA versus AP, p < 0.0001). For 4 hours after discontinuation, more chest drainage occurred with epsilon-ACA than aprotinin (137 +/- 90 mL versus 62 +/- 29 mL; means +/- standard deviation; p < 0.02). Cumulative 12-hour drainage was similar for aprotinin (391 +/- 220 mL) and epsilon-ACA (582 +/- 274 mL), but higher without inhibitor (1,091 +/- 541 mL; p < 0.001 versus drugs). Postoperatively, aprotinin was associated with the lowest autologous retransfusion incidence and highest hematocrits (p < 0.01 versus epsilon-ACA). Homologous transfusion exposures did not differ. CONCLUSIONS: In first-time coronary operations, higher postoperative hematocrit and less shed blood retransfusion constitute only subtle advantages of aprotinin over high-dose epsilon-ACA.

Aminocaproic Acid↗
PubMed1998

Pathophysiology of early failure of autologous aortic heart valves (ATCV).

BACKGROUND: Degeneration remains the major drawback of bioprostheses. Among various concepts to mitigate degeneration, the use of autologous pericardium for intraoperative construction of aortic valves (ATCV) was revived recently. Based on in-vivo studies the problem of tissue failure was claimed to be oversome by short immersion in glutaraldehyde. METHODS: Two often ATCV implanted 1994-1996 had to be replaced because of valvular insufficiency due to leaflet shrinkage or tearing. Pathophysiology of failure was evaluated by light microscopy and immune histology, scanning electron microscopy (SEM) and determination of tissue calcium content (AAS). RESULTS: AAS revealed high calcium levels in the shrunken and low levels in the torn leaflets. Histology demonstrated extensive fiber degeneration without inflammation in the destructed and moderate degeneration in the intact leaflets. SEM showed smooth surfaces in the 'normal' and exposure of collagen in the degenerated leaflet associated with calcification. Tears occurred close to the stents. CONCLUSIONS: Failure of ATCV is characterised by either shrinkage and calcification despite a short tanning or by tearing related to the stent design. Clinical use of ATCV cannot be recommended at present.

Aged↗
PubMed1998

'Soft' Snaring of the coronary artery in minimally-invasive coronary surgery.

A technique is described that allows a simple and safe temporary occlusion of the coronary artery in beating heart procedures using monofilament stay sutures underlaid with small pericardial pads. Postoperative serial levels of Troponin I remained low (<4 ng/L) and control angiography revealed no stenosis in the distal coronary artery.

Coronary Artery Bypass↗
PubMed1998

Clinical and morphological characteristics in Streptococcus bovis endocarditis: a comparison with other causative microorganisms in 177 cases.

AIM: To compare the clinical and morphological characteristics of patients with Streptococcus bovis endocarditis with those of patients with endocarditis caused by other microorganisms. METHODS: 177 consecutive patients (Streptococcus bovis, 22; other streptococci, 94; staphylococci, 44; other, 17) with definite infective endocarditis according to the Duke criteria were included. All patients underwent transthoracic and transoesophageal echocardiography. In 88 patients, findings from surgery/necropsy were obtained. RESULTS: S bovis endocarditis was associated with older patients, with a higher mortality (p = 0.04), and with a higher rate of cardiac surgery (p < 0.001) than other microorganisms, although embolic events were observed less often (p = 0.02). Pathological gastrointestinal lesions were detected in 45% of the patients. Multiple valves were affected in 68% of the patients with S bovis endocarditis and in 20% of those with other organisms (p < 0.001). Moderate or severe regurgitation occurred more often in S bovis endocarditis than with other microorganisms (p = 0.05). When surgery or necropsy was performed, infectious myocardial infiltration of the left ventricle was confirmed histopathologically in 36% of the patients with S bovis endocarditis and in 10% of those with other organisms (p = 0.002). CONCLUSIONS: S bovis endocarditis is a severe illness because of the more common involvement of multiple valves, and of the frequent occurrence of haemodynamically relevant valvar regurgitation and infectious myocardial infiltration.

Adult↗
PubMed1998

Complement C6 deficiency protects against diet-induced atherosclerosis in rabbits.

Low-density lipoprotein (LDL) can be transformed to an atherogenic moiety by nonoxidative, enzymatic degradation. Enzymatically degraded LDL induces macrophage foam cell formation, provokes release of cytokines, and also activates complement. To determine whether complement activation may contribute to atherogenesis, 6 pairs of homozygous C6-deficient rabbits and their non-C6-deficient heterozygous siblings were fed a cholesterol-rich diet for 14 weeks. Cholesterol levels and plasma lipoprotein profiles of the animals in the C6-competent and C6-deficient groups did not significantly differ, and the high density lipoprotein and LDL cholesterol ratios at the end of the experiment were 0.07+/-0.01 and 0.08+/-0.01 (SEM), respectively. However, differences in atherosclerotic plaque formation were discernible macroscopically, with extensive aortic lesions being visible in all C6-competent animals and absent in all C6-deficient animals. Aortas were sectioned from thorax to abdomen, and 10 sections were stained from each aorta. Quantification of atherosclerotic lesions and lumen stenosis with the use of computer-based morphometry documented a dramatic protective effect of C6 deficiency on the development of diet-induced atherosclerosis. We conclude that the terminal complement sequence is centrally involved in atherosclerotic lesion progression.

Animals↗