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Biomedical subjects

C Schlensak

Publications and source records attributed to C Schlensak.

At least 19 recordsLinked to original sources
PubMed2004

Effects of ultrafiltration and peritoneal dialysis on proinflammatory cytokines during cardiopulmonary bypass surgery in newborns and infants.

OBJECTIVES: To assess the impact of balanced ultrafiltration and peritoneal dialysis (PD) on plasma and urinary cytokines and renal dysfunction after cardiopulmonary bypass (CPB) surgery in newborns and infants. METHODS: Twenty-three newborns and infants weighing less than 7 kg and scheduled for operation on congenital malformation were enrolled in this descriptive open clinical study. All patients received conventional ultrafiltration in the CPB rewarming period. Eleven newborns underwent Tenckhoff-catheter implantation in the operation theatre as a routine institutional procedure and received PD after admission to the ICU (the PD [+] group). No PD was used in another 12 patients (the PD [-] group). Interleukins (IL) 6 and 8 were measured four times pre- and post-operatively. Kidney function was assessed by creatinine clearances and urine protein and enzyme analyses. RESULTS: All patients had an uneventful clinical course. Age (10+/-2 days, PD [+] vs. 96+/-19 days, PD [-]), CPB duration (215+/-23 vs. 143+/-20 min), and degree of hypothermia (26+/-1.3 vs. 31+/-0.1 degrees C) differed significantly between the groups. Age, CPB duration and ultrafiltration influenced post-operative IL-levels in an analysis of variance. While there were few differences immediately after the end of ultrafiltration, post-operative levels of IL-6 and IL-8 were higher and more sustained in the newborns (PD [+]) than in the older infants (PD [-]). The median amount of IL-6 and IL-8 removed by ultrafiltration came to 28 and 59% compared to the amount of IL-6 and IL-8 remaining in the blood at the end of CPB. IL-clearance by ultrafiltration was more than 1000-fold and by PD more than 100-fold as effective as IL-clearance by the kidney. While the kidneys showed an unselective mixed glomerular and tubular pattern of injury, during CPB higher serum IL-concentrations correlated with lower urinary IL-clearances in both study groups. CONCLUSIONS: Ultrafiltration and PD are highly effective in removing proinflammatory cytokines. Impaired kidney function was associated with proinflammatory IL-serum concentrations. Thus, we raise the hypothesis that glomerular-filtered proinflammatory ILs damage the proximal tubular cells of the kidney in newborns and infants, thus contributing to post-operative renal dysfunction. Conversely, we conclude that removing proinflammatory ILs by ultrafiltration and PD acts renoprotectively. A future prospective randomised study could demonstrate whether this can indeed improve clinical outcome.

Cardiopulmonary Bypass↗
PubMed2001

[Endoventricular patch plasty in patients with idiopathic dilated cardiomyopathy: an alternative to heart transplantation?].

BACKGROUND: Although the concept of reducing wall tension as a treatment for advanced heart failure is convincing, clinical data from the Batista operation are conflicting. Despite a number of publications, it is not clear whether left ventricular reduction surgery is truly of benefit for patients with idiopathic, dilated cardiomyopathy (DCM). Surgery may reduce wall tension but the reason for dilation and contractile dysfunction remains. Thus, the potential benefit of the operation may be overshadowed by the natural course of the underlying disease. CASES: We report a series of five cases where left ventricular reduction was performed and physiological geometry was restored in patients with DCM by a modification of Dor's endoventricular patch plasty. All patients demonstrated an improvement in cardiac function immediately after the operation. This improvement was sustained in one of the patients at 18 months follow-up. Another patient developed severe heart failure due to therapy resistant ventricular arrhythmia (Lown IVb), and underwent successful transplantation 4 months after ventricular reduction surgery. Left ventricular dilation reoccurred in two patients 9 and 12 months after reduction surgery, and they were listed for transplant. One patient died after 9 weeks due to sepsis and respiratory dysfunction. CONCLUSIONS: Although the endoventricular patch plasty as used in this study is well tolerated by most patients with dilated cardiomyopathy and results in immediate improvement of contractile function, the long-term benefits of this technique for DCM are uncertain. Thus, the technique is currently not an alternative for heart transplantation. However, the procedure may be an option in patients with contraindications for transplantation.

Adolescent↗
PubMed2001

Bronchial artery perfusion during cardiopulmonary bypass does not prevent ischemia of the lung in piglets: assessment of bronchial artery blood flow with fluorescent microspheres.

OBJECTIVE: Blood supply of the lungs during total cardiopulmonary bypass (CPB) is limited to flow through the bronchial arteries. This study was undertaken to assess the bronchial artery blood flow during CPB with fluorescent microspheres in a piglet model. METHODS: We subjected ten piglets (mean weight 5.0+/-0.5 kg) to 120 min of normothermic, total CPB without aortic cross-clamping, followed by 60 min of post-bypass perfusion. Fluorescent microspheres were injected into the left atrium or the aortic cannula or distal to the cannula to assess bronchial artery blood flow before, during and after CPB. The reference samples were taken from the descending aorta. We compared the different sites of injection. Tissue samples of the lungs were taken before and 60 min after CPB. RESULTS: Before CPB, total bronchial artery perfusion was 43.6+/-14.1 ml/min (4.8+/-1.3% of cardiac output) as by injection distal to the aortic cannula. These values were not different when microspheres were injected into the left atrium or the aortic cannula. There was no difference in scatter or in the amount of microspheres in the reference samples among the three injections sites. During CPB, bronchial artery perfusion was significantly decreased (4.4+/-2.4 ml/min vs. 40.0+/-5.0 ml/min before CPB) and returned to baseline values 60 min after CPB. Light microscopy of the tissue samples revealed alveolar septal thickening and a decrease in alveolar surface area after 60 min of reperfusion which was associated with a decreased capacity to oxygenate blood. CONCLUSIONS: (1) Bronchial artery blood flow can quantitatively be assessed during CPB when microspheres are injected into the ascending aorta and the reference samples are taken from the descending aorta. (2) Despite adequate perfusion pressure bronchial artery blood flow is decreased substantially during CPB. (3) The decrease in blood flow and the ultrastructural changes present at the end of CPB suggest the presence of low-flow ischemia of the lung during total CPB.

Analysis of Variance↗
PubMed2001

A technique of heterotopic, infrarenal heart transplantation with double anastomosis in mice.

Mouse heart transplantation is frequently used to investigate mechanisms of rejection and immune response. A fully vascularized technique is presented in which the graft ascending aorta is anastomosed end-to-side to the recipient's aorta and the pulmonary aorta is anastomosed end-to-side to the inferior vena cava using 11-0 Ethilon suture. We suggest that this double anastomosis technique is a valuable tool to investigate immune mechanisms in mice.

Anastomosis, Surgical↗
PubMed2001

Left ventricular reduction for idiopathic dilated cardiomyopathy as alternative to transplant--truth or dare?

BACKGROUND: Although the concept of reducing wall tension a treatment for advanced heart failure is convincing, clinical data from the Batista operation are conflicting. Despite a number of publications, it is not clear whether left ventricular reduction surgery truly benefits patients with idiopathic, dilated cardiomyopathy (DCM). Surgery may reduce wall tension, but the reason for dilation and contractile dysfunction remains. Thus, the potential benefit of the operation may be overshadowed by the natural course of the underlying disease. CASES: We report a series of five cases where left ventricular reduction was performed and physiological geometry was restored in patients with DCM by a modification of Dor's endoventricular patch plasty. All patients demonstrated an improvement in cardiac function immediately after the operation. This improvement was sustained in one of the patients after 18 months of follow-up. Another patient developed severe heart failure due to therapy-resistant ventricular arrhythmia (Lown IV b), and underwent successful transplantation 4 months after ventricular reduction surgery. Left ventricular dilation reoccurred in two patients 9 and 12 months after reduction surgery, and they were listed for transplant. One patient died after 9 weeks due to sepsis and respiratory dysfunction. CONCLUSIONS: Although the endoventricular patch plasty, as used in this study, is well tolerated by most patients with dilated cardiomyopathy, and results in immediate improvement of contractile function, the long-term benefits of this technique for DCM are uncertain. Thus, the technique is currently not an alternative for heart transplantation. However, the procedure may be an option in patients with contraindications for transplantation.

Adolescent↗
PubMed2001

[Explantation of aortic stent-grafts].

BACKGROUND: Endoluminal stent graft placement for the treatment of infrarenal aortic aneurysms (AAA) has gained widespread acceptance because it is associated with lower perinterventional morbidity than conventional transabdominal surgery. In this study the long-term morbidity of the procedure was evaluated. METHODS AND RESULTS: Between 9/94 and 12/98, 150 patients (age = 69.6 +/- 8.5 y; m = 142, f = 8) with AAA were treated by placing an intravascular nitinol stent graft (Stentor, n = 55; Vanguard-System, n = 95; 8 tubular grafts, 142 bifurcated grafts). Initial placement of the stent graft was successful in 144 patients. In 12 % of stent graft placements we encountered one of the following complications (n, days after stent placement): migration or dislocation of the prosthesis (4, 914 +/- 220 d), rupture of the aorta (2, 452 d/802 d), recurrent thrombosis of the stent graft (3, 478 +/- 359 d), endoleak (3, 955 +/- 472 d), infection of the prosthesis (5, 798 +/- 495 d). There was no correlation between the complications and the type of stent used. All of these patients were treated by surgical replacement of the prosthesis with a dacron graft. CONCLUSIONS: 1. The results suggest that most complications are due to a continuation of the disease process leading to loosening of the prosthesis. 2. Explantation of the prosthesis and surgical repair is feasible but bears additional risks. 3. Since the onset of reperfusion of the excluded aneurysm can not be predicted, all patients with infrarenal aortic stent grafts require frequent computer tomographic follow up. 4. Lastly, the results call for further improvements in the design of the stent graft.

Aged↗
PubMed2001

Serious complications that require surgical interventions after endoluminal stent-graft placement for the treatment of infrarenal aortic aneurysms.

BACKGROUND: Endoluminal stent-graft placement for the treatment of infrarenal abdominal aortic aneurysms has gained widespread acceptance because it is associated with lower peri-interventional morbidity than conventional transabdominal surgery. In this study the long-term morbidity of the procedure was evaluated. METHODS AND RESULTS: Between September 1994 and December 1998, 150 patients (age, 69.6 +/- 8.49 years; 142 men, 8 women) with abdominal aortic aneurysms were treated with the placement of an intravascular nitinol stent-graft (Stentor [55] and Vanguard-System [95]); there were eight tubular grafts and 142 bifurcated grafts. Initial placement of the stent-graft was successful in 144 patients. Mean follow-up was 49 +/- 25 months. In 13.3% of stent-graft placements we encountered the following complications: 4 cases of migration or dislocation of the prosthesis (30.5 +/- 7.4 months after placement); 2 ruptures of the aorta (26.7 and 15.0 months after placement); 3 recurrent thromboses of the stent-graft (25.5 +/- 5.3 months after placement); 3 endoleaks (27.5 +/- 15.7 months after placement); and 5 infections of the prosthesis (26.6 +/- 16.5 months after placement). There was no correlation between the complications and the type of stent used. All of these patients were treated by surgical replacement of the prosthesis with a Dacron graft. CONCLUSIONS: (1) The results suggest that most complications are due to a continuation of the disease process leading to loosening of the prosthesis. (2) Explantation of the prosthesis and surgical repair is feasible but bears additional risks. (3) Because the onset of reperfusion of the excluded aneurysm cannot be predicted, all patients with infrarenal aortic stent-grafts require frequent computer tomographic follow-up. (4) Finally, the results call for further improvements in the design of the stent-graft.

Aged↗
PubMed2000

Controlled limb reperfusion with a simplified perfusion system.

UNLABELLED: The goal of revascularisation of an acutely ischemic limb is to prevent the loss of the extremity and to enable return of normal function. Although reperfusion of an ischemic limb is a prerequisite for the preservation or reestablishment of function, it may, in itself, cause further injury. Controlled reperfusion after revascularisation may reduce this injury and may facilitate return of normal function. Thus far, the technique of controlled limb reperfusion required the use of cardiosurgical equipment and has therefore been reserved for cardiac surgery centers. However, the majority of patients with acute limb ischemia are referred to hospitals, where the technical equipment for controlled reperfusion is not available. We modified the technique of controlled limb reperfusion using a simplified perfusion system with a pressure-cuffed bag, which allows controlled reperfusion without the use of a roller pump. The modified reperfusion technique was applied to 9 patients with acute and persistent ischemia of the limbs (mean ischemic period: 21 +/- 21 hours). Controlled reperfusion consisted of a 30 min infusion of a normothermic reperfusate solution, which was mixed with the patient's blood (6:1, blood/reperfusate ratio) distally to the proximal obstruction. RESULTS: Five patients (56%) recovered with normal function of the limb. Two patients (22%) lost the ischemic limb (ischemic periods: 77 h and 9h; creatine kinase before operation: 6230 U/I and 1045 U/I): another two patients (22%) died, who were in profound cardiogenic shock. CONCLUSION: The simplified perfusion system allows to put controlled limb reperfusion into practice in any operating room. The results support the notion that controlled limb reperfusion should be applied in any patient with acute ischemia of an extremity.

Arterial Occlusive Diseases↗
PubMed2000

Palliative treatment of a secondary aortoduodenal fistula by stent-graft placement.

A 64-year-old male was admitted with suspected aortoduodenal fistula 16 years after transabdominal aortic reconstruction for aortoiliac occlusive disease. Computed tomography (CT) and angiography revealed an aortoduodenal fistula and a suture-line aneurysm at the proximal anastomosis. Due to the patient's poor general condition at the time of diagnosis, endoluminal stent-graft implantation was chosen rather than conventional surgery. Successful placement of the stent graft without leakage of contrast medium and with complete exclusion of the fistula was demonstrated by CT. The patient recovered uneventfully and was discharged 10 days after the intervention. Five months later contrast CT indicated a recurrence of the aortoduodenal fistula. Since the patient was now in good general condition the stent graft was removed surgically and an extra-anatomic axillofemoral bypass was implanted. Endoluminal stent-graft Implantation is effective as palliative therapy for aortoduodenal fistulas and is especially valuable in patients with high risk for conventional surgery.

Aortic Diseases↗
PubMed1999

Protection of acutely ischemic myocardium by controlled reperfusion.

The goal of revascularization after acute occlusion of a coronary artery is the return of contractile function and the reduction of mortality. Although reperfusion of ischemic myocardium is a prerequisite for return of function, it may, in itself, cause further injury. Controlled blood cardioplegic reperfusion reduces this "reperfusion injury" and provides maximal myocardial protection. In this article, we review recent advances in surgically controlled reperfusion and speculate on future prospects for myocardial protective techniques in patients with acute coronary artery occlusion.

Cardiopulmonary Bypass↗
PubMed1999

Diagnostic and surgical approach of innominate artery saddle embolus.

Patients with an acute arterial occlusion of the right upper extremity and absent axillary pulse should have a Doppler scan examination before a balloon catheter embolectomy is performed. If there is no arterial pulse detectable, an angiography should be performed afterwards to localize the embolus. In the case of a proximal arterial occlusion of the right arm, the authors recommend this procedure to prevent an embolus dislocation by catheter embolectomy and subsequent cerebral embolization. For direct surgical embolectomy the authors recommend a supraclavicular incision.

Aged↗
PubMed1998

Normoxic cardiopulmonary bypass reduces oxidative myocardial damage and nitric oxide during cardiac operations in the adult.

OBJECTIVE: Hyperoxic cardiopulmonary bypass is widely used during cardiac operations in the adult. This management may cause oxygenation injury induced by oxygen-derived free radicals and nitric oxide. Oxidative damage may be significantly limited by maintaining a more physiologic oxygen tension strategy (normoxic cardiopulmonary bypass). METHODS: During elective coronary artery bypass grafting, 40 consecutive patients underwent either hyperoxic (oxygen tension = 400 mm Hg) or normoxic (oxygen tension = 140 mm Hg) cardiopulmonary bypass. At the beginning and the end of bypass this study assessed polymorphonuclear leukocyte elastase, nitrate, creatine kinase, and lactic dehydrogenase, antioxidant levels, and malondialdehyde in coronary sinus blood. Cardiac index was measured before and after cardiopulmonary bypass. RESULTS: There was no difference between groups with regard to age, sex, severity of disease, ejection fraction, number of grafts, duration of cardiopulmonary bypass, or ischemic time. Hyperoxic bypass resulted in higher levels of polymorphonuclear leukocyte elastase (377 +/- 34 vs 171 +/- 32 ng/ml, p = 0.0001), creatine kinase 672 +/- 130 vs 293 +/- 21 U/L, p = 0.002), lactic dehydrogenase (553 +/- 48 vs 301 +/- 12 U/L, p = 0.003), antioxidants (1.97 +/- 0.10 vs 1.41 +/- 0.11 mmol/L, p = 0.01), malondialdehyde (1.36 +/- 0.1 micromol/L,p = 0.005), and nitrate (19.3 +/- 2.9 vs 10.1 +/- 2.1 micromol/L, p = 0.002), as well as reduction in lung vital capacity (66% +/- 2% vs 81% +/- 1%,p = 0.01) and forced 1-second expiratory volume (63% +/- 10% vs 93% +/- 4%, p = 0.005) compared with normoxic management. Cardiac index after cardiopulmonary bypass at low filling pressure was similar between groups (3.1 +/- 0.2 vs 3.3 +/- 0.3 L/min per square meter). [Data are mean +/- standard error (analysis of variance), with p values compared with an oxygen tension of 400 mm Hg.] CONCLUSIONS: Hyperoxic cardiopulmonary bypass during cardiac operations in adults results in oxidative myocardial damage related to oxygen-derived free radicals and nitric oxide. These adverse effects can be markedly limited by reduced oxygen tension management. The concept of normoxic cardiopulmonary bypass may be applied to surgical advantage during cardiac operations.

Adult↗
PubMed1998

Transmyocardial laser revascularization (TMLR) in patients with unstable angina and low ejection fraction.

OBJECTIVE: Does perioperative use of the intraaortic balloon pump (IABP) improve the postsurgical outcome of patients presenting with endstage coronary artery disease, unstable angina and low ejection fraction transferred for transmyocardial laser revascularization (TMLR)? METHODS: TMLR, as sole therapy combined with the perioperative use of an intraaortic balloon pump has been assessed in seven patients with endstage coronary artery disease, unstable angina and low ejection fraction (EF < 35%). Six out of seven patients had signs of congestive heart failure. These patients are compared with 23 patients with endstage coronary artery disease, stable angina and EF > 35%, who were treated with TMLR as sole therapy without the use of IABP. The creation of transmural channels was performed by a CO2-laser. All patients were evaluated by hybrid positron emission tomography (perfusion SPECT and viability PET) and ventriculography preoperatively. Echocardiography, clinical status and hemodynamic assessment by Swan Ganz catheter were performed perioperatively. RESULTS: The perioperative mortality of this combined procedure (TMLR and IABP) was zero. Three out of seven patients had pneumonia with complete recovery. Swan Ganz catheter examinations showed deterioration of LV-function after TMLR intraoperatively and improvement after 2 h and further after 6 h on ICU (P < 0.05). In contrast, a decrease of LV-function in sole TMLR patients with an EF > 35%) has not been observed. Patients with EF < 35% needed the IABP for 2.3 days and moderate dose catecholamines for a mean of 3.0 days. The postoperative EF and resting wall motion score index (WMSI) of all analysed LV segments (evaluated by echocardiography) did not change compared to baseline (EF 31.3+/-2.6 preop. to 32.8+/-3.2 postop.; WMSI: 1.75+/-0.14 at baseline to 1.71+/-0.17 postop.). The average Canadian Angina Class at the time of discharge decreased from 4.0+/-0 (baseline) to 2.3+/-0.5 (P < 0.05) and the NYHA-Index from 3.9+/-0.3 to 2.7+/-0.5. No patient had signs of angina pectoris, whereas two patients still had signs of congestive heart failure. CONCLUSIONS: The reported data support our concept to start IABP preoperatively in patients with reduced LV contractile reserve in order to provide cardiac support during the postoperative phase of reversible decline of LV-function induced by TMLR.

Aged↗
PubMed1998

Clinical experience with blood cardioplegia.

Since its initial description, blood cardioplegia has become the preferred tool to arrest the heart for open heart surgery in both children and adults. This shift from crystalloid-type cardioplegia to blood cardioplegia occurred because experimental and clinical studies demonstrated superior protection of the arrested myocardium by blood cardioplegia. In this article we review and describe the different strategies and protocols which have evolved for the use of blood cardioplegia under different conditions. The protocols differ in the composition of the crystalloid component of the solution, the direction of delivery (antegrade, retrograde, or both), and/or the temperature of the solution. In order to maxime myocardial protection, specific protocols for the administration of blood cardioplegia have been designed for specific clinical conditions. We further define the indications for the use of the different protocols. Our own clinical experience with blood cardioplegia is corroborated with the concepts and results described in the literature. We conclude that blood cardioplegia is 1.) an effective way to safely arrest the myocardium for cardiac operations, 2.) affords excellent myocardial protection, and 3.) allows for quick recovery of contractile function upon reperfusion.

Adult↗