Search PubMed⌕ Search

Biomedical subjects

S Hagl

Publications and source records attributed to S Hagl.

At least 19 recordsLinked to original sources
PubMed2002

The index of pulmonary vascular disease in children with congenital heart disease: relationship to clinical and haemodynamic findings.

OBJECTIVE: We asked whether a scoring system [index of pulmonary vascular disease (IPVD)] that quantifies the individual pulmonary vascular pathology would relate to postoperative survival in patients with congenital heart disease and pulmonary hypertension (PH). METHODS: Lung biopsy specimens from 28 patients at a median age of 6 months (1 month to 21 years) were analysed qualitatively and morphometrically. The IPVD and other morphometric parameters were related to haemodynamic findings and survival. RESULTS: Mean pulmonary artery pressure (PAP) was 44 mmHg (15-72 mmHg), and the resistance to pulmonary perfusion was 5 U x m(2) (0.9-14 U x m(2)). There were three early (in-hospital) and three late deaths during the follow-up period of 2.5 years (6 months to 7 years). Incipient plexiform lesions were observed in one infant with trisomy 21 and complete atrioventricular septal defect (cAVSD). An IPVD score above the upper critical limit (>2.2) was not observed during the first year of life. On discriminant analysis, morphometric parameters could not predict mortality ( P=0.08). CONCLUSIONS: The IPVD is not helpful to predict surgical mortality during the first year of life. Patients with trisomy 21 and cAVSD may show advanced pulmonary vascular disease in infancy.

Child↗
PubMed2002

Effects of trifluoperazine on the contraction kinetics of the isolated intact tracheal and pulmonary artery smooth muscle.

BACKGROUND: We studied the effect of the calmodulin antagonist trifluoperazine (TFP) on isolated intact rat tracheal and pulmonary artery smooth muscle contractile behaviour. METHODS: Experimental series: 1) TFP-dose-response curves for TFP's effect on force generation were constructed using rat tracheal smooth muscles and rat pulmonary artery preparations (n = 8). A concentration of 1 micromol/l TFP was chosen for the subsequent experimental series. 2) Tracheas and pulmonary arteries (n = 14) were dissected in three segments. One of them was used immediately for experiments ("native"), the other two were treated for 12 h in 4 degrees C Tyrode solution without ("12 h cold storage") or with 1 micromol/l TFP ("12 h cold storage + TFP"). These preparations contracted after supramaximal effective electrical field stimulation. The force-clamping technique was used to analyse kinetic and mechanical parameters of smooth-muscle contraction in both types of preparation (measurement conditions: resting tension 2 mN, 37 degrees C, modified Krebs-Henseleit solution). RESULTS: 1) TFP decreased developed force dose-dependently in pulmonary artery and tracheal smooth muscle. 2) During sustained tonic activation, the contraction kinetics become slower both with and without TFP treatment (p < 0.0001). 3) TFP caused a dramatic retardation of the velocity of force generation in both types of preparation for any given time interval during the course of a tonic activation (p < 0.0005). 4) The dramatic effects of TFP on the contraction kinetics were not associated with effects on the extent of force generation. CONCLUSIONS: These results support the assumption that tracheal and pulmonary artery smooth muscle cross-bridge rates are controlled by a calcium-calmodulin-dependent myosin light chain kinase. This finding suggests the involvement of a calmodulin-independent regulator process responsible for the changes observed in the cross-bridge cycling rates during sustained tonic activation. A direct intervention on the contractile apparatus level is a measure for reduction of smooth-muscle tone without negative inotropic side effects.

Animals↗
PubMed2002

Minimal early mortality in CABG--simply a question of surgical quality?

BACKGROUND: The increasing number of risk scores and models for the evaluation of the early risk after cardiac surgery reflects the interest in 'calculating' the risk of adverse events. Different time intervals, but also different 'types' of death are generally accepted in the evaluation of early mortality. The aim of this study was to focus on the differences in the calculation of early mortality and to focus on their potentially misleading impact on risk stratification. METHODS: We investigated 7,436 patients who underwent coronary artery bypass grafting from June 30, 1988 through June 30, 2001. A follow-up was performed 180 days after operation (98.7 % complete). RESULTS: According to the definition of 30-day mortality to represent the total time interval between an intervention and the 30th postoperative day, the 30-day mortality was 5.92 % (n = 440 patients). Hospital mortality reflects the number of deaths from the day of intervention through the patient's individual discharge, independent of any fixed time interval. Hospital mortality was 5.86 % (n = 436 patients) in our patient group. 30-day hospital mortality requires the investigation of hospital mortality until the 30th postoperative day; in-hospital and general mortality after the 30th postoperative day remained excluded from the analysis; 30-day hospital mortality was 5.19 % (n = 386 patients). Assuming a maximum hospital stay of 5 days, hospital mortality would decrease to 2.64 % (n = 196 patients). CONCLUSIONS: 30-day mortality, hospital mortality and 30-day hospital mortality are used to determine early outcome. The present data indicate the vulnerability of non-standardized time intervals to discharge policy. However, both hospital mortality and 30-day hospital mortality are predominantly used in current risk scores and models. In view of the comparability and meaning of data, the methodology for the evaluation of early risk should be reconsidered.

Coronary Artery Bypass↗
PubMed2002

Dopexamine attenuates microvascular perfusion injury of the small bowel in pigs induced by extracorporeal circulation.

BACKGROUND: Cardio-thoracic surgery with the use of extracorporeal circulation may lead to an impairment of splanchnic perfusion. The aim of this study was to investigate the effect of dopexamine on gastrointestinal microvascular perfusion failure due to extracorporeal circulation. METHODS: Twenty landrace pigs served as laboratory animals. A loop of the terminal ileum was exteriorized for microscopic observation. In 13 animals a partial left-heart bypass (pLHB), with a non-pulsatile pump flow of approximately 50% of the cardiac output, was established for 2 h. Seven animals received a continuous i.v. infusion of 3 micrograms kg-1 min-1 dopexamine from the beginning of pLHB to the end of the experiment. Seven sham-operated animals served as controls. The microcirculatory network was analysed by means of intra-vital microscopy prior to, during pLHB, and 2 h after bypass. RESULTS: Despite normal haemodynamics measured by arterial pressure and cardiac output, pLHB led to significant impairment of microvascular perfusion characterized by arteriolar vasoconstriction, reduction of functional capillary density (FCD) to 30% 2 h after weaning off bypass and diminished blood-cell velocities in submucous venules. Dopexamine attenuated this perfusion impairment, preventing arteriolar vasoconstriction. FCD remained normal. CONCLUSION: Our data demonstrate that treatment with the vasoactive drug dopexamine leads to a significant reduction of the perfusion injury of the small bowel.

Adrenergic beta-Agonists↗
PubMed2002

Perfusion-contractility matching during Fontan circulation.

We investigated the relationship between coronary perfusion pressure (CPP) and myocardial contractility and the effects of an acute elevation of right atrial pressure (RAP) on this relationship in an experimental model of Fontan circulation in 6 anesthetized open-chest dogs with isolated perfused coronary arteries. The relationship between CPP and Ees could be described by biphasic J-shaped curves which were nearly identical before and under Fontan circulation. While above a "critical" CPP (72 +/- 9 mmHg vs. 81 +/- 8 mmHg, n.s.) the changes of CPP did not affect Ees, below this level the decrease of CPP resulted in a progressive decrease of Ees. Under Fontan circulation, the progressive increase of RAP did not influence Ees at CPP = 100 mmHg, led to a moderate decrease of Ees at CPP = 75 mmHg and severe decrease at CPP = 60 mmHg. Thus, both coronary arterial and venous pressure affect myocardial contractility after Fontan procedure.

Animals↗
PubMed2002

[Multi-value regulatory systems for extracorporeal circulation].

Extracorporeal perfusion is the standard technique in cardiac surgery. It is controlled by perfusionists on the basis of their clinical experience and on the available data collected pre- and intra-operatively. But in spite of intensive monitoring postoperative complications occur. An appropriate control of the heart-lung machine (HLM) using an "autopilot" might improve the quality of heart-surgery and decrease postoperative complications. Hence, a mathematical model of a human circulatory system has been developed which provides much more information about haemodynamics, blood gases and acid-base status than standard monitoring. It has been implemented on a system which is capable of integrating measured data as input parameters in real-time in the simulation. Now, soft- and hardware control concepts based on the human circulatory system have to be developed which are able to control the HLM.

Coronary Disease↗
PubMed2002

[Computer-assisted reconstruction of coronary vessels].

End stage coronary artery disease with linear stenosis of the main vessels despite several coronary interventions is a current challenge for surgical treatment. As the long term results are mainly determined by the pathology of the coronary vessels a simple revascularisation with arterial or venous grafts provides no adequate solution of the problem. An exactly controlled 3D-reconstruction of the coronary vessels enabling selective thrombendarteriectomy (TEA) seems to be a new approach, that may be limited by neointimal hyperproliferation of the coronary vessels. Intraoperative brachytherapy may be a tool to inhibit this process.

Atherectomy, Coronary↗
PubMed2002

[Stability of the Euro-score as an identification tool for patient risk groups -- dependency of the applied documentation system].

From the different methods for risk adjustment, scores allow a rough classification of the patients. The Euroscore represents one of the most modern scores. The most recent version of the documentation system of the German Society for Thoracic and Cardiovascular Surgery may be used without extended extra-work to evaluate the Euroscore despite the presence of various limitations. The investigation of the scores with nearly complete adaptation of the variables of the quality assurance documentation to the original definition showed no substantial differences between the score groups. However, many methodological implications favor the development of self-evaluated models to obtain a most recent weight for each risk factor and to be able to take into account new therapeutical options. These models can be evaluated by the existing database and extended by the most recent data.

Cardiac Surgical Procedures↗
PubMed2001

[Aortic dissection--when operative treatment, when endoluminal therapy?].

GOAL: To demonstrate the Heidelberg results of the previous 2 years in patients referred for acute aortic dissection. MATERIAL AND METHODS: 93 patients referred for acute aortic dissection were treated by cardiac surgery, vascular surgery and interventional radiology according to a novel therapeutic algorithm including stent-grafts and combined open and interventional procedures and conservative medical therapy when no malperfusion syndrome was present or patients were considered prohibitive for even minor surgical procedures. Stent-graft placements were done assisted by short term cardiac arrest to facilitate correct device deployment. RESULTS: 36 patients presented with type A and the other 57 with type B dissection. 32 of the A patients were operated and 20 of the B patients, respectively. 12 patients with B dissection were treated with stent-grafts. 3 required additional interventional therapy for organ malperfusion. The mortality was 0% in these 12 patients The overall mortality rate in the A group was close to 40% mainly as a result of postoperative organ malperfusion while it was 15% in the B group. In both groups mortality was highest in the respective untreated patient subgroup (3/4 and 8/37, respectively). The main mortality factor was visceral (mesenteric or liver) ischemia. Paraplegic complications occured in neither group. In 4 patients a combined approach applying cardiac surgery of the ascending aorta and endluminal stent-graft placement for the residual B dissection was successfully performed. In one patient this was done simultaneously. DISCUSSION: Acute aortic dissection of type A with or without valve involvement, coronary artery ischemia can be treated with high technical success rates. However, remaining distal aortic dissection associated with true lumen collapse and organ malperfusion is the main causative factor for clinical failures. Successful combination of open proximal aortic surgery with endoluminal treatment of residual B dissection encourages further use of this novel approach. Acute B type dissection appears to be effectively and safely treated by endoluminal approach in selected cases. Unsolved questions of this less invasive therapeutic approach focus mainly on the design of the proximal anchoring part of the devices.

Acute Disease↗
PubMed2001

Systolic and diastolic properties and myocardial blood flow in the heterotopically transplanted rat heart during acute cardiac rejection.

The aim of the study was to characterize the course of systolic and diastolic function, myocardial blood flow, and histologic changes during acute rejection in a model of heterotopic transplantation in rats. For this purpose isogenic Lewis-to-Lewis and allogenic DA (Dark Agouti)-to-Lewis rat cardiac transplants were studied 1 hour and 1, 3, and 5 days, respectively, after heterotopic intraabdominal transplantation. Myocardial tissue blood flow (MBF) was assessed by the hydrogen-clearance method. An implanted balloon was used to measure pressure-volume relations in the transplanted heart. Myocardial water content was determined at the end of the experiments, and histologic examinations were performed. The MBF recovered during the first day postoperatively in both groups and decreased again in the allogenic group after 3 and 5 days (p < 0.05); it remained stable in the isogenic group. Myocardial relaxation was already prolonged in the allogenic group after 3 days and deteriorated further. Left ventricular end-diastolic pressure progressively increased in the allogenic group, whereas it remained unchanged in the isogenic group up to 5 days. After recovery from ischemia, the left ventricular peak systolic pressure was stable in the isogenic group for the entire further observation period, but it significantly decreased in the allogenic group after 5 days (p < 0.05). Myocardial water content showed a significant increase in the allogenic group compared to that in the isogenic group after 5 days. In the allogenic group histologic examination confirmed mild to moderate rejection after 3 days and severe acute rejection after 5 days. Thus, after recovery from ischemia, mild to moderate cardiac rejection was associated with reduced MBF and impaired relaxation. In a typical sequence, generation of edema and impaired diastolic compliance were terminally followed by systolic dysfunction during severe rejection.

Animals↗
PubMed2001

[Myocardial revascularization after pretreatment with the GPIIb/IIIa receptor blocker abciximab].

AIM: The present prospective study analysis whether preoperative abciximab treatment 1) increases perioperative risks, 2) alters the quality of the surgical treatment, 3) whether secondary organ complications occur and 4) whether and how the perioperative surgical management has to be modified. METHODS: The perioperative results of patients operated upon after preoperative abciximab treatment (n = 31, 1/1994-4/2000) were compared with an optimal control group (elective patients and no preoperative intervention in the hemostaseological system) and with other patients (elective, urgent, emergency operations) receiving different strategies of preoperative hemostaseological interventions (n = 926, 1/1994-4/2000). All patients were operated upon with a well-defined strategy (one surgeon). 1100 perioperative items/patient were prospectively recorded and analyzed. The 30-day and 6 month follow-up was complete. RESULTS: The mean time interval between end of abciximab therapy and onset of operation was 4.3 h (range: 36-0.5 h, median: 2 h). As compared with the optimal control group (n = 81), perioperative blood loss and the need for substitution of blood and blood products was increased. However, as compared with those patients receiving any type of preoperative intervention in the hemostaseological system (the majority of the patients), no difference was observed regarding intraoperative parameters (duration of extracorporeal circulation and of the operation) and postoperative results (neurological, renal complications, myocardial infarction, psychiatric disturbances, etc.) when abciximab patients were compared with the reference populations. No patient of the abciximab group died within 30 days or during the 6 month follow-up period. CONCLUSION: The data show that coronary artery bypass grafting can be performed with similar results in abciximab-pretreated patients as in patients with other types of preoperative anticoagulation. Only slight modifications of the surgical management are recommended. As indicated by similar use IMA-grafts the quality of surgical treatment was not reduced.

Abciximab↗
PubMed2001

[Thrombolysis of prosthetic heart valve thrombosis using recombinant tissue plasminogen activator (rt-PA) in infancy and childhood].

Thrombotic obstruction of a mechanical cardiac valve prosthesis requires urgent therapy. We report on the treatment of prosthetic valve thrombosis with recombinant tissue plasminogen activator (rt-PA) in three children at the age of 4, 10 and 18 months, in whom a St. Jude Medical prosthesis had been placed at the atrioventricular valve level 2 to 6 weeks earlier. The initial rt-PA dose was 0.4 mg/kg given over 15 min and followed by a continuous daily infusion of 1.6 to 2.0 mg/kg. In addition the patients received heparin (200 U/kg/d). Thrombolytic therapy was administered for a range of 4 to 28 days. The therapy was successful in the first case. The second child had four recurrent events of prosthetic valve thrombosis and the thrombolytic therapy was successful three times. However, the prosthesis had to be finally replaced. In the third case the thrombolytic therapy was only partially successful due to an organized thrombus requiring prosthesis replacement.

Age Factors↗
PubMed2001

Influence of steroids on microvascular perfusion injury of the bowel induced by extracorporeal circulation.

BACKGROUND: Extracorporeal circulation is associated with gastrointestinal complications. By means of intravital microscopic methods, we investigated whether preoperative treatment with steroids can attenuate the impairment of the bowel microcirculation. METHODS: In 20 pigs, a partial left heart bypass (pLHB) was established. A loop of the terminal ileum was exteriorized for intravital-microscopic observation. Seven sham-operated animals served as controls. In 13 animals, pLHB was established for 2 hours with a flow rate of 2,000 mL per minute; 7 of the animals received 20 mg/kg body weight prednisolone preoperatively. The microcirculatory network was analyzed before, during pLHB, and 2 hours after bypass. RESULTS: Despite unchanged macro-hemodynamics, pLHB resulted in a significant microvascular perfusion injury of the small bowel. Arteriolar vasoconstriction and a reduction of perfused capillaries per unit area (functional capillary density) to 30% of prebypass values could be found. Blood cell velocities were reduced in submucuous collecting venules. In the steroid-treated animals, the functional capillary density remained normal. In addition, arteriolar vasoconstriction could be prevented. CONCLUSIONS: Treatment with prednisolone largely prevents the microcirculatory alterations in the small bowel induced by extracorporeal circulation.

Animals↗