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Objective: Biological valves exhibit characteristic curves (CC) regarding transvalvular gradient, resistance, and effective orifice area when correlated with a physiological cardiac output range (CO). The slope of the curve of transvalvular resistance over a typical CO range characterizes the clinical performance of the valve. These information may support an individualized decision towards the most adequate valve type., Methods: In an extracorporeal mock circuit two types of stented biological aortic valves (constructed pericardial valves, Edwards Perimount: EP; porcine cusp valves, Medtronic Mosaic: MM) of 21, 23, and 25 mm were investigated. Mean transvalvular gradient was measured over a range of 1.9 to 7.2l/min CO at a simulated heart rate of 70 beats/min. Transvalvular resistance was calculated and presented as characteristic curves in a log-log-plot against cardiac output., Results: EP valves of all sizes demonstrated low slopes (resistance range; slope: 21 mm: 53-79 dynes s cm(-5); 0.29; 23 mm: 44-56 dynes s cm(-5); 0.12; 25 mm: 38-45 dynes s cm(-5); 0.12) while MM valves exhibited steep slopes (resistance range; slope: 21 mm: 46-169 dynes s cm(-5); 0.97; 23 mm: 36- -146 dynes s cm(-5); 0.95; 25 mm: 27-64 dynes s cm(-5); 0.68)., Conclusions: While constructed pericardial valves demonstrate sufficient hemodynamic performance especially in the higher CO range porcine cusp valves exhibited minor resistance in the lower CO range. Patients who exercise regularly may therefore profit from a pericardial valve while patients with a small body surface area and little exercise who therefore remain in the lower CO range may be adequately treated with a porcine cusp valve.

We report the surgical treatment of a Bland-White-Garland syndrome (BWG-syndrome) of adult type in a 61-year old female patient. Coronary catheterization revealed an anomalous origin of the left coronary artery from the trunk of the pulmonary artery. Based on excellent collateral perfusion of the artery from the right coronary artery, ligation near its origin from the pulmonary artery was attempted via a minimally-invasive approach. No saphenous vein bypass was implanted, no reimplantation of the anomalous vessel in the aorta was performed. The patient recovered uneventfully without signs of ischemia. Appearance of BWG-syndrome in adults is very rare, especially without symptoms of myocardial ischemia. The different modalities of the treatment of these syndromes in adult patients are often debated. In this case, closure without revascularisation appeared to be appropriate.

Background: Temporary intraluminal shunts (TILS) are routinely used in off-pump revascularization to facilitate the anastomosis while maintaining myocardial blood supply. Whereas tourniquet-occlusion can cause vessel wall trauma, potentially adverse chronic effects of TILS on the coronary intima have not been evaluated yet. This chronic large animal study investigated ultrastructural effects of TILS on the vessel wall., Methods: Four groups of acute and chronic pigs with either tourniquet-occlusion (TOUR) or TILS (40 kg; acute, n = 12; chronic, n = 20) were analyzed. Animals underwent median sternotomy, heparin (150 U/kg) administration, and left anterior descending coronary artery exposure. In groups with TOUR the left anterior descending coronary artery was temporarily occluded (10 minutes) with a tourniquet. In groups with TILS a silicone shunt (1.5 mm diameter, 12 mm length) was placed in the left anterior descending coronary artery more than 10 minutes and then removed, and the insertion was repaired. Thirty minutes after reperfusion all acute animals were sacrificed whereas chronic animals were extubated, maintained for 3 months, and then sacrificed. The left anterior descending coronary artery regions of occlusion or placement of the TILS silicone bulbs were examined histopathologically by scanning and transmission electron microscopy by a blinded pathologist., Results: In both acute and chronic investigations animals in the TILS group exhibited significantly less morphologic damage than animals in the TOUR group. In the acute phase significantly more loss of cell junction (p = 0.037), loss of endothelium (p = 0.032), and intimal edema (p = 0.037) in the TOUR group than in the TILS group was observed. Three months later, characteristic features with a changed pattern were detected: vacuolization of the cell (p = 0.03), loss of cell junction (p = 0.042), and removal of basal membrane (p = 0.046) as well as extensive loss of endothelium (p = 0.003) in the TOUR group compared with the TILS group., Conclusions: Intimal lesions occur with both maneuvers early and late. However, animals in the TOUR group exhibited injuries significantly more often and more severely. Therefore, acute and chronic intimal integrity of the coronary vessel may be better preserved using TILS and may thus have a positive impact on the extent of de novo stenosis and long-term prognosis of the revascularized region.

Background: Mechanical bileaflet valves with enhanced inner diameter may offer superior hemodynamic properties in patients with a small aortic annulus. The aim of this clinical study was to compare these valves with standard bileaflet prostheses in vivo., Methods: Mechanical aortic valve replacement for combined stenosis and regurgitation was performed in 47 patients with standard CarboMedics prostheses (CM: 21 mm, 23 mm, 25 mm) and two types of diameter enhanced St. Jude Medical prostheses (SJM-AHPJ: 21 mm, 23 mm, 25 mm; SJM-Regent: 21 mm, 23 mm). Transvalvular mean gradients (TVG) were assessed intraoperatively by means of transesophageal echocardiography (TVG(TEE)) and simultaneous direct pressure monitoring of the left ventricle and the ascending aorta (TVG(CATH)), as well as early (3 months) and late (9 months) postoperatively by means of transthoracic echocardiography (TVG(TTE)). Left ventricular muscle mass was assessed preoperatively, early, and late postoperatively to evaluate remodeling capacity., Results: In all valve types and sizes, both TVG assessments exhibited consistent findings. Small-sized conventional valves of 21 mm showed a marked initial TVG. In contrast, both valve types with enhanced inner diameter exhibited significantly lower TVG comparable with those achieved with larger valves (TVG(CATH) CM 21 mm, 15.6 +/- 3.9 mm Hg; SJM-AHPJ 21 mm, 11.9 +/- 1.6 mm Hg; SJM-Regent 21 mm, 9.9 +/- 1.1 mm Hg; CM 23 mm, 7.8 +/- 0.8 mm Hg; SJM-AHPJ 23 mm, 7.7 +/- 1.4 mm Hg; SJM-Regent 23 mm, 9.5 +/- 1.8 mm Hg). During the postoperative course TVG remained constant in all valve types and sizes. Left ventricular muscle mass, however, diminished markedly in all valves without exhibiting significant differences between size matched valve types., Conclusions: In patients with a small aortic annulus, who require a 21-mm valve, diameter-enhanced prostheses provide lower transvalvular gradients than conventional valves. However, in the intermediate clinical course, appropriate left ventricular remodeling occurred in all patients independent of the size and the type of the valve.

Objective: MIDCAB and OPCAB revascularization is currently performed with temporary tourniquet occlusion of the coronary artery to achieve a bloodless surgical field. However, a trauma of the vessel wall due to snaring sometimes occurs. The use of temporary intraluminal shunts (TILS) have recently been advocated as an alternative. The aim of this experimental study was to evaluate the acute ultrastructural effects of TILS versus tourniquet occlusion on the coronary vessel wall., Methods: Twelve pigs (40+/-3 kg) were investigated. In group A (n=6) the left anterior descending (LAD) artery was temporarily occluded with a tourniquet over 20 min. In group B (n=6) a commercially available silicone TILS (1.5-mm diameter, 12-mm length, AnastaFlo, Research Medical Inc.) was placed in the LAD. After 20 min perfusion the TILS was removed and the insertion was repaired. After 30 min reperfusion all animals were killed. Three LAD territories of each animal were examined histopathologically by scanning electron microscopy (SEM), light microscopy (LM) and transmission electron microscopy (TEM). Areas of occlusion or placement of the TILS olives were investigated., Results: SEM revealed ultrastructural alterations in both groups. While marked intimal rupture appeared in all animals of group A, only two of the six animals of group B exhibited superficial endothelial abrasions. LM showed differences of intimal thickness in all groups while TEM revealed severe edema of subendothelial tissue in four of six animals in group A., Conclusion: The intimal lesions observed after tourniquet occlusion in our experimental off-pump surgery model confirmed other recent studies. In contrast, utilization of TILS caused only minor damage of the vessel wall. The endothelial abrasions detected in this group may be a consequence of micro-dislocations or insertion maneuvers. Chronic studies are necessary to verify as to whether the mild injury after TILS insertion will result in a reduction or even absence of de-novo stenoses compared with tourniquet occlusion.

Objective: Conventional extracorporeal circulation results in an activation of coagulation cascades. Coating of extracorporeal circulation tubes as well as avoidance of shed blood recirculation have been shown to reduce these phenomena. We evaluated a new shed blood separation system (AVANT D 970) utilizing a coated cardiopulmonary bypass tube system (PHISIO)., Methods: Forty patients (62 +/- 10 years) underwent isolated coronary revascularization. Four groups (n = 10/group) were defined: no extracorporeal circulation, conventional uncoated extracorporeal circulation, uncoated extracorporeal circulation with shed blood separation, and coated extracorporeal circulation with shed blood separation. Thrombin-antithrombin complex and free Hb were analyzed and statistically compared., Results: Conventional extracorporeal circulation exhibited the highest intraoperative activation of coagulation (thrombin-antithrombin complex: extracorporeal circulation, 31.1 +/- 15.8 microg/L; uncoated extracorporeal circulation with shed blood separation, 15.3 +/- 7.8 microg/L; coated extracorporeal circulation with shed blood separation, 8.1 +/- 4.8 microg/L; no extracorporeal circulation, 2.4 +/- 0.6 microg/L; P <.05 extracorporeal circulation vs all others) and red blood cell damage (free Hb: extracorporeal circulation, 16.8 +/- 11.4 micromol/L; uncoated extracorporeal circulation with shed blood separation, 10.3 +/- 3.5 micromol/L; coated extracorporeal circulation with shed blood separation, 6.8 +/- 2.9 micromol/L; no extracorporeal circulation, 3.4 +/- 1.1 micromol/L; P <.05 extracorporeal circulation vs no extracorporeal circulation, coated extracorporeal circulation with shed blood separation). Coated extracorporeal circulation with shed blood separation showed only slight activation and cell trauma, which did not differ significantly from no extracorporeal circulation., Conclusions: Combination of coating and avoidance of shed blood recirculation maintained physiological coagulation levels and markedly reduced red blood cell trauma in extracorporeal circulation procedures. These combined modalities may therefore offer an alternative for off-pump procedures in patients with contraindications for conventional extracorporeal circulation.

This report describes the case of a 60-year-old man, who developed a giant punch-hole aneurysm of the ascending aorta five month after uncomplicated coronary artery bypass grafting (CABG) due to a localized rupture of the ascending aorta. The patient underwent surgical repair with cardiopulmonary bypass. Because the false aneurysm was adherent to the sternum, resternotomy was performed in deep hypothermia and circulatory arrest. The lesion in the ascending aorta was closed by means of a dacron-patch. The postoperative course of the patient was completely uneventful. We recommend to repair a false aneurysm of the ascending aorta in deep hypothermic circulatory arrest (DHCA) in order to avoid excessive blood loss during sternotomy.

Objective: Optimal preservation of postischemic graft function is essential in lung transplantation. Antegrade flush perfusion with modified Euro-Collins solution represents the standard technique worldwide. However, growing evidence suggests the superiority of extracellular-type Perfadex solution (Vitrolife AB, Gothenburg, Germany) over Euro-Collins solution. During ischemia and reperfusion, endogenous pulmonary nitric oxide synthesis is decreased, and therefore therapeutic stimulation of the nitric oxide pathway might be beneficial in ameliorating ischemia-reperfusion damage. However, research mainly focuses on nitric oxide supplementation of intracellular solutions, and no studies exist in which the effect of nitroglycerin on Perfadex preservation quality is evaluated., Methods: Eight rat lungs each were preserved with Perfadex solution with or without nitroglycerin (0.1 mg/mL) and compared with low-potassium Euro-Collins solution. Postischemic lungs were reventilated and reperfused, and oxygenation capacity, pulmonary vascular resistance, and peak inspiratory pressures were monitored continuously. Stereological analysis was used for evaluation of pulmonary edema and assessment of the vasculature. Statistics were performed by using different analysis of variance models., Results: The oxygenation capacity of the Perfadex-preserved groups was higher compared with that of the low-potassium Euro-Collins solution group (P <.03). By using nitroglycerin, flush-perfusion time was reduced, and Perfadex solution with nitroglycerin-protected lungs showed superior oxygenation capacity compared with that seen in Perfadex solution-protected organs (P <.01). Furthermore, pulmonary vascular resistance and peak inspiratory pressures were improved in the nitroglycerin group (P <.01). Stereology revealed comparable intrapulmonary edema between groups and a trend toward less vasoconstricted vasculature in Perfadex with nitroglycerin-protected lungs., Conclusions: Perfadex solution provides superior lung preservation in terms of postischemic oxygenation capacity than Euro-Collins solution. Supplementation of the nitric oxide pathway by nitroglycerin further enhances functional outcome of Perfadex-preserved organs and might be an easily applicable tool in clinical lung transplantation.

Reconstruction of the aortic valve and replacement of the ascending aorta instead of use of a composite graft is the preferred method in patients, who demonstrate an ascending aneurysm accompanied by aortic root enlargement and aortic valve insufficiency with morphologically intact cusps. Two techniques inaugurated by David and Yacoub have gained widespread acceptance. However, both approaches are technically demanding. We present a simplified alternative technique for aortic valve reconstruction by means of a reduction plasty of the aortic root without the necessity of transection maneuvers.

Objective: Intermittent antegrade warm blood cardioplegia (IAWBC) is a simple and cost-effective method of myocardial preservation. However, there are only few prospective trials comparing this type of cardioplegia to established cardioplegic strategies in elective on-pump coronary surgery with respect to myocardial protection and outcome., Methods: In a prospective, randomized trial IAWBC (33 degrees C) (n=100) was compared to intermittent antegrade cold (4 degrees C) blood cardioplegia (n=100), regarding clinical outcome and myocardial protection using cardiac troponin-I (cTNI) and creatine kinase MB isoenzyme (CK-MB) measurements to assess ischemia., Results: Preoperative parameters were comparable in both groups. Results demonstrated no differences in-between the groups regarding mortality (2.0% both), incidence of perioperative myocardial infarction (2 versus 3%), need for intra-aortic balloon pump (3 versus 4%), length of ICU stay (2.0+/-2.5 versus 2.1+/-3.0 days) and incidence of postoperative atrial fibrillation (41 versus 34%). However, the necessity of defibrillation after cardiac arrest (18 versus 43%, P<0.001) was significantly less frequent and of lower intensity (3.4+/-10.8 versus 10.8+/-20.6 J, P<0.001) in the IAWBC-group. Postoperatively the ischemia markers were significantly lower in the IAWBC-group, cTNI within the first 72 h (from P<0.001 to P=0.013) and even CK-MB within the first 24 h (from P=0.004 to P<0.011)., Conclusion: IAWBC is a safe and simple method in elective on-pump coronary artery bypass surgery. Significantly lower ischemic markers suggest an improved myocardial protection compared to cold blood cardioplegia in these patients.

Objectives: Severe sclerosis of the native aortic annulus can result in a tilted implantation position of mechanical prostheses. In this study, the effects of tilting and rotation on the hemodynamic performance of standard bileaflet valves were assessed in an extracorporeal mock circulatory system., Methods: A pulsatile mock circulation driven by a Berlin Heart system was developed. Main physiological components of the human circulation were mimicked. SJM-AHPJ prostheses (21, 23, 25 mm) were mounted in an artificial aortic root containing physiologically oriented coronary ostia. All experiments were performed under constant conditions (stroke volume 60 ml, heart rate 70 bpm, systolic pressure 130 mmHg). Hydrostatic pressures were measured via fluid-filled catheters, transvalvular flow by ultrasonic probes. Data were digitally recorded at 50 Hz. Multiple pressure, volume, energy, and dimension parameters were derived off-line. Each valve was tested in a 0 degrees (untilted) versus 20 degrees (tilted) position at three axial rotation angles (0 degrees, 45 degrees, 90 degrees ). Tilting was performed independent of rotation by elevation of the prosthesis in the non-coronary sinus., Results: In all valves and all rotation angles, tilting resulted in a size-dependent significant increase of mean pressure gradient (range, 28-35% [21 mm valve], 59-96% [23 mm valve], 124-220% [25 mm valve]), valvular resistance (39-51, 84-121, 177-332%), regurgitation volume (84-148, 32-131, 93-118%), and systolic energy loss (113-146, 30-132, 69-213%), as well as a decrease of total stroke volume (2-5, 0-11, 3-10%), effective stroke volume (6-11, 9-14, 14-22%), cardiac output (6-11, 8-14, 13-22%), and effective opening area (16-24, 32-37, 47-57%). The strongest impairment of hemodynamic performance was seen at 90 degrees rotation with reference to total and effective stroke volume, cardiac output, mean pressure gradient, and regurgitation fraction., Conclusions: Tilting of bileaflet valves resulted in a significant impairment of systolic and diastolic hemodynamics. Superiority of larger valves diminished in the tilted position. The strongest tilting effect was seen at 90 degrees rotation. Such a position should therefore be avoided or surgically corrected by rotating the valve.

Background: The steady rise in complex cardiac procedures as well as the increase in comorbidity often result in a prolonged intensive care unit (ICU) stay. As a consequence, considerable numbers of patients have to be transferred to other hospitals so that the primary institution can maintain its capacity. The purpose of this study was to investigate the outcome of these patients., Methods: 1,175 consecutive patients underwent various open heart procedures. 115 patients (9.8 %) requiring prolonged ICU treatment were retrospectively analyzed. 74 patients (EuroSCORE 8.1) underwent transferral to either rehabilitation units with ventilation capacity, multidisciplinary ICUs, or cardiac ICUs. 41 patients (EuroSCORE 7.9) remained in our hospital. Morbidity, mortality, and clinical condition were assessed and compared., Results: Transferred patients exhibited an overall mortality of 38 % compared to only 17 % in patients who remained. Mortality was 81 % in rehabilitation units, 30 % in multidisciplinary ICUs, and 16 % in cardiac ICUs. 66 % of the survivors among the transferred patients showed significantly impaired clinical condition (NYHA III-IV) compared to 33 % who showed a good postoperative condition (NYHA I-II). The patients who remained exhibited 44 % NYHA III-IV and 56 % NYHA I-II., Conclusion: Transferral of patients after prolonged intensive care stay to external hospitals carries significant risks for early death and impaired outcome. However, transferral to cardiac ICUs appears to be an adequate option. Further studies may identify potential subgroups of patients who do not benefit from transferral.

Objective: Extracorporeal lung-perfusion models are widely used to evaluate pulmonary preservation techniques and reperfusion injury. However, these models mainly depend on nonpulsatile flow, which is not physiological and can subsequently lead to pulmonary edema. Observation in a standardized setting and reliability of functional and structural data assessment are therefore limited. To overcome these limitations we developed a new extracorporeal large animal lung perfusion model utilizing pulsatile flow to perfuse the pulmonary vasculature., Methods: Lungs of juvenile domestic pigs were in situ preserved with 2 liters Perfadex and stored for 3 h at 10 degrees C. Thereafter, reperfusion of the lung was performed in an extracorporeal blood perfusion circuit employing either a modified roller pump with pulsatile module (300 ml/min; pulsation rate 90/min) or a standardized roller pump with continuous flow (30 ml/min). Ventilation was performed with physiologic room air (350 ml; 16/min) for 1 h. Pulsatile and nonpulsatile perfusion was performed in 2 groups (group NP: nonpulsatile; group P: pulsatile flow, n = 7) during reperfusion. Peak inspiratory pressure (PIP), mean pulmonary artery pressure (PAP), and oxygenation capacity (DeltaPO(2)) were continuously measured. For control of the effectiveness of the pulsatile perfusion pressure waveforms were obtained directly from the native pulmonary artery of both groups. Malondialdehyde (MDA) as a parameter for lipid peroxidation and endothelial cell damage was assessed at 10, 30 and 50 min reperfusion. At the end of the study, pulmonary water content was assessed by means of wet-to-dry ratio (W/D ratio). The tissue was further processed for microscopic analysis., Results: PIP increased significantly in both groups during reperfusion. Mean PAP in both groups increased to 60 mm Hg after 20 min followed by a decrease after 60 min to 40 mm Hg. Pressure waveforms of the pulmonary artery showed sufficient pulsatility in the pulmonary vasculature with a systolic/diastolic pressure difference of 15 mm Hg whereas the pressure difference was 3-5 mm Hg in the nonpulsatile group. DeltaPO(2) was stable in groups NP and P during reperfusion (30 min: NP: 66.4 (62.2-88) mm Hg; P: 74.8 (65-81.7) mm Hg) without any statistically significant differences between the groups. MDA in group NP decreased over the reperfusion period from 6.2 (3.3-6.3) microM at 10 min to 5.2 (3.2-6.1) microM at 50 min, whereas in group P the level increased and was significantly higher after 50 min reperfusion compared to group NP [6.6 (6.1-9.2) microM at 50 min; p = 0.016]. W/D ratio was 6.7 (6.3-7.0) in group NP and 6.8 (6.3-7.6) in group P. Light microscopy evaluation showed no differences between both groups regarding severity of intra-alveolar and interstitial edema and numbers of intra-alveolar, intracapillary and interstitial granulocytes., Conclusion: Although effective pulsatile perfusion of the pulmonary vasculature was achieved by means of a modified roller pump, this measure obviously did not improve functional parameters nor did it significantly reduce the edema formation after 3 h ischemia in this extracorporeal lung perfusion model. The use of pulsatile perfusion is therefore not mandatory in the extracorporeal setting of a large animal lung perfusion model., (Copyright 2002 S. Karger AG, Basel)

Background: Indication for immediate revascularization during acute myocardial infarction (MI) is debated. Drug-resistant crescendo angina, as well as hemodynamic compromise, however, often requires acute operation. In this study the differential risks of acute coronary artery bypass grafting with and without MI were stratified., Methods: Five hundred eighteen patients undergoing isolated coronary artery bypass grafting were investigated. Thirty-nine patients underwent acute revascularization because of enzyme-proven or electrocardiogram-proven MI accompanied by crescendo angina, hemodynamic compromise, or both. They were compared with 33 emergent, 63 urgent, and 383 elective patients without MI. Preoperative risk factors for early mortality and necessity of continuous venovenous hemofiltration were analyzed by means of logistical regression analysis. Perioperative data were compared., Results: Early mortality of the MI cohort was 15.4%, in contrast to 15.2% in emergent, none in urgent, and 2.1% in elective patients. Left internal thoracic artery was used in 87% of MI, 97% of emergent, 94% of urgent, and 97% of elective patients. Intraaortic balloon pump was necessary in 50% of MI patients, 27% of emergent, 6.3% of urgent, and 3.1% of elective cases. Continuous venovenous hemofiltration was performed in 29% of MI patients, 15% of emergent, 4.9% of urgent, and 3.4% of elective patients. Hemodynamic instability significantly increased the odds ratio for early mortality and continuous venovenous hemofiltration., Conclusions: Patients undergoing acute revascularization carried an elevated risk to die early notwithstanding the presence or absence of acute MI. Liberal use of left internal thoracic artery grafts was not detrimental in acute patients whereas liberal use of intraaortic balloon pump was beneficial. In almost 30% of MI patients, continuous venovenous hemofiltration was not necessary, implying a severely impaired perioperative hemodynamic condition. Immediate revascularization in the presence of acute MI is therefore indicated although it may be addressed as a separate high-risk group.

Background: Minimally invasive direct coronary artery bypass is an established clinical procedure for revascularization of the left anterior descending coronary artery. Mechanical stabilization and temporary occlusion is currently used to perform the anastomosis of the internal thoracic artery to the left anterior descending coronary artery. However, critical reduction of cardiac function can occur as a result of temporary ischemia. The purpose of this study was to evaluate whether ischemic sequelae can be avoided by using temporary intraluminal shunts and whether this alters early outcome., Methods: Thirty-five patients underwent minimally invasive direct coronary artery bypass revascularization using a mechanical stabilizer. In group A (n = 20), the anastomotic site was temporarily occluded by tourniquets. In group B (n = 15), temporary intraluminal shunts were inserted into the anastomotic site without any occlusion of the left anterior descending coronary artery. Anastomosis of the internal thoracic artery to the left anterior descending coronary artery was performed in an identical fashion. A Swan-Ganz catheter was inserted, and transesophageal echocardiographic measurements were obtained for analysis of left ventricular (LV) function. Regional wall motion, cardiac index, stroke volume index, systolic and diastolic LV diameters, and fractional area change were measured during four periods: at the start of the operation (baseline), placement of the stabilizer (stabilization), left anterior descending coronary artery occlusion (occlusion) or insertion of temporary intraluminal shunts (shunt), and 30 minutes after reperfusion (reperfusion). Angiograms were obtained 4 to 6 days postoperatively., Results: In group A, LV performance, cardiac index, stroke volume index, and fractional area change decreased during occlusion whereas systolic diameters increased. Almost two myocardial segments per patient developed severe hypokinesia in the perfusion area. These changes disappeared after 30 minutes of reperfusion, with increased LV function. In group B, LV function remained stable whereas hypokinetic wall motion was only detected in 2 patients. Early angiograms revealed 90% of the grafts were patent in group A versus 100% in group B. The need for percutaneous intervention during the first 6 months was 20% in group A versus 6.7% in group B., Conclusions: The use of temporary intraluminal shunts resulted in reduced acute ischemia and revealed wall motion abnormalities and maintained LV function. Furthermore, this technique suggests an improvement of early graft patency and a lower reintervention rate within the first 6 postoperative months. Thus, use of temporary intraluminal shunts appears to be superior to the occlusion technique early after minimally invasive direct coronary artery bypass procedures.

Objective: The therapeutic strategy in non-small-cell lung cancer (NSCLC) requires exact staging of tumour invasion (T) as well as differentiation between ipsi- and contralateral lymph node invasion (N1/2 vs N3). [18F]FDG-positron emission tomography (FDG-PET) has been shown to detect invaded N with high accuracy while correct determination of T appears to be unclear. The purpose of this prospective study was to evaluate benefit and necessity of 18FDG-PET as an additive to conventional staging modalities., Methods: Forty patients with suspected non-small-cell lung cancer (NSCLC) were staged by means of computed tomography (CT), bronchoscopy, mediastinoscopy and bone scintigraphy. Additionally, attenuation corrected FDG-PET of the thorax was performed pre-operatively for analysis of T and N topography. After surgical resection with radical lymphadenectomy T and N staging results of CT and PET were compared with the pathological diagnoses. Specificity, sensitivity, positive predictive value and accuracy of CT and PET were calculated., Results: Twenty three squamous cell carcinomas, 14 adenocarcinomas, and three non-malignant tumours were found. Accuracy of CT-T was 0.75 and of PET-T 0.78; accuracy of CT-N was 0.78 and of PET-N 0.80. By combination of CT-T and PET-T accuracy was 0.88. Combination of CT-N and PET-N yielded an accuracy of 0.90. In two out of three cases, PET correctly determined T0. In two cases non-malignant inflammatory lymph nodes were falsely staged as malignant by PET., Conclusions: Adequate pre-operative T- and N-staging is possible with both CT and FDG-PET. Accuracy can be improved by combination of CT and FDG-PET. FDG-PET is superior to CT in order to differentiate between malignant and benign tumours. However, acute inflammation can mimic malignant lymph node invasion. FDG-PET is justified as a supporting staging measure in cases presenting unclear differentiation between N2 and N3 after conventional staging and is helpful in cases with unclear cell type of the primary tumour., (Copyright Harcourt Publishers Limited.)

Background: Extracellular preservation solutions utilizing high molecular agents can reduce intracellular edema during ischemia/reperfusion in lung transplantation. A solution of 40,000 dalton molecular weight (DMW) has already been clinically established (Perfadex). However, it is unclear whether dextrans of this particular size represent the optimal additive for lung preservation solutions., Materials and Methods: In a new ex vivo porcine lung model, lungs were each preserved with low-potassium solutions containing 5% dextran with 90,000 DMW (Dex 90) and 160,000 DMW (Dex 160) and with Perfadex (40,000 DMW). After 24 h of cold ischemia, reperfusion was performed employing a roller pump with a pulsatile module. Lungs were perfused with deoxygenated perfusate and ventilated with room air. The oxygenation capacity (Delta pO(2)), peak inspiratory pressure (PIP), and mean pulmonary artery pressure (PAP) were monitored for 60 min. Net weight gain (NWG) and wet-to-dry ratio (W/D ratio) were determined. Free-radical generation was assessed by measuring malondialdehyde (MDA) at 10, 30, and 50 min., Results: PIP and PAP increased in all groups significantly during reperfusion. However, Dex 160-perfused lungs exhibited significantly higher values than those with Dex 90 and Perfadex. Perfadex showed the highest Delta pO(2) throughout the entire reperfusion, while Delta pO(2) was slightly reduced in Dex 160 and significantly lower in Dex 90. In Perfadex the lowest water content was observed assessed by NWG and W/D ratio. The highest MDA values were observed in Dex 90, followed by Dex 160, while the lowest values were seen in Perfadex., Conclusions: Preservation of the lung with Perfadex exhibited superior postischemic function in contrast to preservation solutions containing dextrans with a higher molecular weight.

Purpose: The aim of this study was to demonstrate the possibilities of a hybrid rendering method, the combination of a color-coded surface and volume rendering method, with the feasibility of performing surface-based virtual endoscopy with different representation models in the operative and interventional therapy control of the chest., Material and Method: In 6 consecutive patients with partial lung resection (n = 2) and lung transplantation (n = 4) a thin-section spiral computed tomography of the chest was performed. The tracheobronchial system and the introduced metallic stents were visualized using a color-coded surface rendering method. The remaining thoracic structures were visualized using a volume rendering method. For virtual bronchoscopy, the tracheobronchial system was visualized using a triangle surface model, a shaded-surface model and a transparent shaded-surface model., Results: The hybrid 3D visualization uses the advantages of both the color-coded surface and volume rendering methods and facilitates a clear representation of the tracheobronchial system and the complex topographical relationship of morphological and pathological changes without loss of diagnostic information. Performing virtual bronchoscopy with the transparent shaded-surface model facilitates a reasonable to optimal, simultaneous visualization and assessment of the surface structure of the tracheobronchial system and the surrounding mediastinal structures and lesions., Conclusions: Hybrid rendering relieve the morphological assessment of anatomical and pathological changes without the need for time-consuming detailed analysis and presentation of source images. Performing virtual bronchoscopy with a transparent shaded-surface model offers a promising alternative to flexible fiberoptic bronchoscopy.

Surgical correction of anterior thoracic wall deformities is an extensive procedure with considerable operative trauma. The procedure can be markedly supported by means of preoperative 3D spiral-computed tomography for the purpose of improved preoperative planning in order to avoid unnecessary tissue mobilization. It is also helpful to enhance the patients' comprehension regarding the operative requirements.

We report the case of a 65-year-old male who developed an oropharyngeal carcinoma, an oesophageal carcinoma and two primary bronchial carcinomas in combination with a renal cell carcinoma as an additional primary entity. By means of an aggressive diagnostic regimen including radiological and nuclear imaging techniques all carcinomas were detected early and could be treated with curative intention., (Copyright 2000 Harcourt Publishers Ltd.)

Exceptionally few cases worldwide have survived weaning from a biventricular assist device following heart transplantation in contrast to those who underwent early retransplantation. We present a successful outcome after biventricular assist device implantation following initial biventricular failure after heart transplantation. Weaning could be performed after 1 week, although pulmonary vascular resistance remained markedly elevated.

Ischaemia/reperfusion (I/R) injury, a major problem in clinical lung transplantation, is associated with surfactant dysfunction. The present study aimed to test the hypothesis that preservation related improvements in post-ischaemic lung function are associated with improved ultrastructural preservation of pulmonary surfactant. Rat lungs were flush perfused with modified Euro-Collins solutions (ECS), stored for 2 h at 4 degrees C, and reperfused for 40 min. Lungs were preserved with conventional (ECS 115: 115 mmol x L(-1) K+), medium-K+ (ECS 40: 40 mmol x L(-1) K+), or low-K+ (ECS 10: 10 mmol x L(-1) K+) ECS. Functional parameters were monitored during reperfusion (n=10 per group). After reperfusion, left lungs were prepared for electron microscopical and stereological analysis of surfactant (n=5 per group). In all three experimental groups notable I/R injury developed which was lowest in ECS 40 as indicated by significantly less intraalveolar oedema, higher perfusate oxygenation, and lower peak inspiratory pressure. This was associated with a significantly superior preservation of the ultrastructure of the surface active surfactant subtype tubular myelin in ECS 40 compared with ECS 115 and ECS 10. Stereological analysis revealed that the relative amount of tubular myelin was highest in ECS 40 (mean+/-SEM; 6.2+/-0.8%) compared with ECS 115 (3.0+/-1.0%) and ECS 10 (2.7+/-1.6%). Analysis of surfactant in its natural location within the organ showed that the severity of ischaemia/reperfusion injury correlates with differences in intraalveolar surfactant composition. Improved post-ischaemic respiratory function achieved by medium-K+ Euro-Collins solution is associated with superior ultrastructural preservation of tubular myelin. It is concluded that the integrity of surface active tubular myelin represents an important criterion for the assessment of lung preservation quality.

Background: We previously demonstrated that the supplement of both dibutyryl cyclic adenosine monophosphate (db-cAMP) and nitroglycerin to the conventional ET-Kyoto solution improved lung preservation significantly. However, the significance of each component in lung preservation remained unclear. We examined the efficacy of the two components on lung preservation in the current study., Methods: Rat lung grafts (eight per group) were studied in an isolated lung perfusion model. Group 1 grafts were flushed and preserved with ET-Kyoto solution containing 2 mmol/L of db-cAMP. Group 2 grafts were flushed and preserved with ET-Kyoto solution containing 100 mg/L of nitroglycerin. In group 3, the grafts were flushed and preserved with ET-Kyoto solution containing neither db-cAMP nor nitroglycerin as control group. After 4-hour cold storage, the lung grafts were reperfused for 50 minutes., Results: The lung grafts in groups 1 and 2 showed significantly better lung function after reperfusion than those in group 3 with regard to arterial oxygen tension, shunt fraction, peak inspiratory airway pressure, mean pulmonary arterial pressure, and pulmonary vascular resistance. The supplementation of db-cAMP improved especially the pulmonary arterial pressure and pulmonary vascular resistance, while the supplementation of nitroglycerin improved especially the oxygenation and airway pressure of the grafts., Conclusions: Both of db-cAMP and nitroglycerin had beneficial effects on lung preservation and are essential to the ET-Kyoto solution. There was a difference between the two components in the effects on preserved lungs.

Unlabelled: Acute hypersensitivity reactions are serious complications of reexposure to aprotinin. Previous contact via infusions or fibrin tissue adhesives can induce specific antibodies. In this study, we aimed to elucidate the preoperative prevalence of aprotinin-specific antibodies in patients scheduled for cardiac operations. Sera of 520 consecutive cardiosurgical patients were collected preoperatively and screened retrospectively for aprotinin-specific IgG using a standard enzyme-linked immunosorbent assay (ELISA). Positive sera were analyzed also for aprotinin-specific IgA (ELISA) and IgE (fluorescence enzyme immunoassay). The histories of all patients were reviewed with focus on aprotinin preexposure. Of 520 patients, 22 (4%) had specific IgG. Only three of these had a documented aprotinin preexposure. Of 448 patients exposed to aprotinin intraoperatively, 15 had preformed specific antibodies. The only patient presenting with severe anaphylaxis was positive for both IgG and IgE, and had a recent IV preexposure in cardiovascular surgery. The presence of aprotinin-specific IgG alone seems not to induce adverse reactions on exposure. Exposure history alone is not sensitive enough to identify patients with aprotinin-specific antibodies., Implications: Anaphylaxis on IV reexposure to aprotinin is a medical emergency. The clinical significance of preformed aprotinin-specific IgG remains questionable, whereas preformed IgE was present in the only patient who suffered from severe anaphylaxis on reexposure to aprotinin. Preformed antibodies are not reliably predicted by exposure history.

Ischemia and reperfusion (I/R) result in surfactant dysfunction. Whether the impairment of surfactant is a consequence or a cause of intraalveolar edema formation is still unknown. The cumulative effects of lung perfusion, ischemic storage, and subsequent reperfusion on surfactant ultrastructure and pulmonary function were studied in a rat isolated perfused lung model. The left lungs were fixed for electron microscopy by vascular perfusion either immediately after excision (control; n = 5) or after perfusion with modified Euro-Collins solution (EC), storage for 2 h at 4 degrees C in EC, and reperfusion for 40 min (n = 5). A stereological approach was chosen to discriminate between intraalveolar surfactant subtypes of edematous regions and regions free of edema. Intraalveolar edema seen after I/R in the EC group occupied 36 +/- 6% (mean +/- SEM) of the gas exchange region as compared with control lungs (1 +/- 1%; p = 0.008). Relative intraalveolar surfactant composition showed a decrease in surface active tubular myelin (3 +/- 1 versus 12 +/- 0%; p = 0.008) and an increase in inactive unilamellar forms (83 +/- 2 versus 64 +/- 5%; p = 0.008) in the EC group. These changes occurred both in edematous (tubular myelin, 3 +/- 1%; unilamellar forms, 88 +/- 6%) and in nonedematous regions (tubular myelin, 4 +/- 3%; unilamellar forms, 77 +/- 5%). The ultrastructural changes in surfactant were associated with an increase in peak inspiratory pressure during reperfusion. In conclusion, surfactant alterations seen after I/R are not directly related to the presence of edema fluid in the alveoli. Disturbances in intraalveolar surfactant after I/R are not merely the result of inactivation due to plasma protein leakage but may instead be responsible for an increased permeability of the blood-air barrier, resulting in a vicious cycle of intraalveolar edema formation and progressing surfactant impairment.

Early graft dysfunction after lung transplantation is a significant and unpredictable problem. Our study aimed at a detailed investigation of structure-function correlations in a rat isolated heart-lung model ofischemia/ reperfusion injury. Variable degrees of injury were induced by preservation with potassium-modified Euro-Collins solutions, 2 hr of cold ischemia, and 40 min of reperfusion. Pulmonary artery pressure (Ppa), pulmonary vascular resistance (PVR), peak inspiratory pressure (PIP), and perfusate gases (deltaPO2, deltaPCO2) were recorded during reperfusion. Right lungs were used to calculate W/D-weight ratios. Nineteen experimental and six control left lungs were fixed for light and electron microscopy by vascular perfusion. Systematic random samples were analyzed by stereology to determine absolute and relative volumes of lung structures, the amount of interstitial and intraalveolar edema, and the extent of epithelial injury. Lectin- and immunohistochemistry using established epithelial cell markers were performed in three animals per group to reveal sites of severe focal damage. Experimental lungs showed a wide range in severity of ischemia/ reperfusion injury. Intraalveolar edema fluid amounted to 77-909 mm3 with a mean of 448+/-250 mm3 as compared with 22+/-22 mm3 in control lungs (P<0.001). Perfusate oxygenation (deltaPO2) decreased from 30.5+/-15.2 to 21.7+/-15.2 mm Hg (P=0.05) recorded after 5 and 40 minutes of reperfusion. In experimental lungs, a surface fraction of 1% to 58% of total type I pneumocyte surface was damaged. Intraalveolar edema per gas exchange region (Vv ape,P) and deltaPO2 were related according to deltaPO2 = 96 - 60 x log10(Vv ape,P) [mm Hg]. The extent of epithelial injury did not correlate with deltaPO2 nor with intraalveolar edema, but increased significantly with PVR. Lectin- and immunohistochemistry revealed focal severe damage to the alveolar epithelium at the border of perivascular cuffs.

Background: Exact staging of ipsi- and contralateral mediastinal lymph-node metastases (N 1/2 vs. N3) is essential for the therapeutic strategy in non-small-cell lung cancer (NSCLC). CT and mediastinoscopy are the standards of reference for N staging. However, even with these combined measures the extent of invasion of mediastinal lymph nodes can remain vague. 18FDG Positron Emission Tomography (18FDG-PET) has recently been shown to detect invaded nodes with high accuracy. The purpose of this study was to evaluate 18FDG-PET as an aid in N staging., Methods: 27 patients with suspected NSCLC were clinically staged by means of CT, bronchoscopy, mediastinoscopy, and bone scintigraphy. Additionally, 18FDG-PET was performed preoperatively for analysis of topography of invaded lymph nodes. CT and 18FDG-PET were evaluated in a blinded fashion. Surgical therapy was performed with radical lymphadenectomy. CT N staging as well as PET N staging results were compared with the pathological diagnoses (pTN). Specificity, sensitivity, and accuracy of CT and PET in N staging were calculated., Results: 14 squamous-cell carcinomas, 10 adenocarcinomas, and 3 non-malignant tumors were found. In 8 patients no invasion was found (N0), in 13 patients an ipsilateral invasion (N1/2), and in 3 patients a contralateral invasion (N3). In the correct detection of N1/2 the sensitivity of CT and of PET was 0.77, the specificity of CT and of PET was 0.79. The accuracy of CT was 0.74 and of PET 0.78. By combining CT and PET accuracy was 0.85., Conclusions: Adequate preoperative LN staging is possible with both CT and 18FDG-PET. The accuracy, however, can be improved by a combination of CT and 18FDG-PET.

The objective of this study was to investigate the role of contrast enhancement using a three-dimensional (3D) phase-contrast (PC) magnetic resonance (MR) sequence (3D PC-MRA) and to assess the value of a dynamic MR perfusion study of the kidneys to determine the hemodynamic relevance of unilateral renal artery stenosis (RAS). Seventeen patients with unilateral RAS were examined on a standard 1.0 T imaging system using a phase shift and magnitude sensitive 3D PC sequence (TR=160 ms, TE=9 ms, venc. 30 cm/s). Following the initial pre-contrast 3D PC-MRA a dynamic first pass perfusion study was performed using a Turbo-FLASH 2D sequence (TR=4.5 ms, TE=2.2 ms, TI=400 ms) after bolus injection of 0.15 mmol gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA)/kg body weight. The 3D PC-MRA was then repeated during infusion of 0.15 mmol Gd-DTPA/kg body weight. Evaluation by three independent readers was based on maximum intensity projection images. Source images were rendered on request. Signal intensity (SI) over time curves of the renal cortex were obtained from the dynamic perfusion study and analyzed for maximum signal enhancement as well as temporal relationship to the aortic SI curve. Results from 3D PC-MRA revealed a sensitivity (pre-/post-contrast) of 100%/89%, specificity of 76%/63%, positive predictive value of 80%/69 %, negative predictive value of 90%/78%, and accuracy of 85%/75% (p=0.07). Interobserver agreement was kappa=0.61/kappa=0.47 (pre/post Gd-DTPA), respectively. Increased signal-to-noise was present in all segments of the renal arteries post contrast (p=0.0003). This came along with image degradation due to aliasing and elevated SI of venous flow that partially obscured the renal arteries. Dynamic SI curves showed a significantly decreased maximum SI in RAS (p=0.01-0.001). A temporal delay of cortical signal intensity enhancement could not be confirmed in this setting. Gd-enhanced 3D PC-MRA did not yield a superior diagnostic value in the diagnosis of RAS compared to pre-contrast measurements. Dynamic perfusion imaging of the kidneys, in combination with 3D PC-MRA, can contribute additional information in suspected unilateral RAS.

Background: Low-potassium solutions have been shown to improve lung preservation. The optimal potassium concentration, however, has not been investigated systematically. The purpose of this study was to evaluate the effect of solutions with different potassium concentrations on functional and structural preservation after flush-perfusion and ischemia. We used our established extracorporeal working heart-lung model and a modification of this model with isolated pulmonary perfusion at defined flow rates., Methods: In two sets of experiments 42 rat heart-lung blocks (experiment I and II: n=7/group) were used. Lungs were flush-preserved with 20 ml Euro-Collins solution (EC115; K+ 115 mmol/L), potassium-reduced Euro-Collins solution (EC40; K+ 40 mmol/L), or low-potassium Euro-Collins solution (EC10; K+ 10 mmol/L) and stored for 2 hours at 10 degrees C. Reperfusion was performed for 40 minutes with Krebs-Henseleit solution containing washed bovine red blood cells (38%) while the lungs were ventilated with room air. In experiment I pulsatile perfusion of the lungs was achieved by the working right side of the heart. In experiment II lungs were perfused at defined flow rates by a roller pump. Postischemic function was assessed by means of oxygenation capacity and pulmonary vascular resistance. The degree of structural damage to the air-blood barrier was assessed by quantitative stereologic light and electron microscopic evaluation., Results: In both experiments after 40 minutes reperfusion oxygenation capacity was significantly higher in EC40 than in EC115 and EC10, whereas pulmonary vascular resistance was significantly higher in EC115 than in EC40 and EC10. Quantitative histologic examination showed surprisingly modest damage to the endothelial side of the air-blood barrier but a considerable degree of damage to the epithelium in both experiments. The alterations in the pump-perfused isolated lung experiments exceeded those of the pulsatile perfused heart-lung experiments. The comparative analysis of the study groups revealed a minor degree of epithelial swelling and fragmentation in EC40 than in EC115 and EC10, respectively., Conclusions: The results obtained with two modifications of an extracorporeal model indicate that flush perfusion of the lung with a potassium-reduced solution results in better functional and structural preservation than flush perfusion with either high- or low-potassium solutions. The optimum may lie in the vicinity of 40 mmol/L. Further studies are necessary to verify these initial findings.

Persistent mediastinitis despite primary revision, closed irrigation therapy, and additional secondary omental plasty is a life threatening situation in cardiac surgery. We managed this rare complication in one instance by sternectomy and hemirectus plasty as well as bilateral pectoralis plasty.

In recent years several potassium-reduced solutions have been developed for improvement of pulmonary preservation. A comparison of these solutions in a single study, however, has not yet been performed. In an extracorporeal working rat heart-lung model (n = 7/group) lungs were preserved with 20 ml Euro-Collins (EC), low potassium EC (LPEC), low potassium 2% dextran (LPD), ET-Kyoto (ETK) or low potassium 5% dextran (Perfadex) solution, while hearts were arrested with 10 ml St. Thomas' cardioplegia. Lungs of controls were not perfused. The heart-lung blocks were stored for 2 h at 10 degrees C. Thereafter, heart-lung blocks were extracorporeally perfused with Krebs-Henseleit solution with washed bovine red blood cells. Coronaries were perfused with oxygenated perfusate. Lungs were perfused via the working right ventricle with deoxygenated perfusate and ventilated with room air. Oxygenation capacity (dPO2) and pulmonary vascular resistance (PVR) were measured. Reperfusion/ventilation was performed for 40 min. At the end of the experiment the wet to dry (W/D) ratio of lungs and light microscopic assessment of the degree of edema (0-4) were performed. All potassium-reduced solutions showed superior dPO2 and a lower PVR than EC and controls while LPEC exhibited the most stable dPO2 and lowest PVR after 30 min reperfusion. The W/D ratio of all potassium-reduced groups was lower than the ratio of EC and controls. In LPEC, ETK and Perfadex the least degree of edema was noted. All solutions used in this study are superior to regular EC. However, when compared directly, LPEC perfused lungs showed better functional preservation than all other alternative solutions.

The optimal temperature of the pulmonary flush perfusate is still a matter of controversy. At present, a temperature of 10 degrees C is favored. This study deals with the structural and functional impact of different perfusate temperatures on lung preservation. In an extracorporeal rat heart-lung model lungs were preserved with Perfadex solution of 4, 15 and 25 degrees C and submitted to 2 h ischemia. Heart-lung blocks harvested from male rats were perfused with Krebs-Henseleit solution and ventilated with room air. Lungs were perfused with deoxygenated perfusate via the working right ventricle while the coronary arteries were retrogradely perfused with oxygenated perfusate. Oxygenation capacity (dPO2), peak inspiratory pressure (PIP) and pulmonary vascular resistance were measured. After establishment of baseline functional parameters hearts were arrested with 10 ml St. Thomas cardioplegia and lungs were flushed with 20 ml Perfadex solution. The heart-lung block was then stored for 2 h at 10 degrees C. Reperfusion was performed thereafter under the same conditions. At the end of the trial the lung tissue water was measured by the wet/dry ratio. The perfusion time of the groups flushed with 15 or 25 degrees C perfusate was significantly lower than that of the 4 degrees C group. After 20 min reperfusion dPO2 of the groups flushed with 15 or 25 degrees C was superior to those submitted to a 4 degrees C flush perfusion. PIP was significantly lower in the 15 degrees C group than in the 4 and 25 degrees C groups. The wet/dry ratio revealed the smallest water content in the 15 degrees C group. We conclude that the post-ischemic lung function is dependent on the temperature of the flush perfusate. Among the tested temperatures, perfusion at 15 degrees C showed the best results. The optimum may therefore lie in this range.

Background: The addition of dextran with a molecular weight of 40,000 Dalton in pulmonary preservation solutions has proved to be beneficial. However, dextrans of other size have not yet been investigated. Therefore, it is unclear whether dextran 40,000 represents the optimal additive for lung preservation solutions., Method: In a working rat heart-lung model, lung were preserved with regular Euro-Collins solution or with Euro-Collins solution containing 5% dextran of different sizes: 40,000 Dalton molecular weight; 70,000 Dalton molecular weight; 160,000 Dalton molecular weight. After 2 hours of ischemia functional (oxygenation; pulmonary vascular resistance) and structural (wet/dry-ratio, light microscopy) data were assessed and the amount of dextran in the lung tissue was measured., Results: Lungs preserved with Euro-Collins solution 70,000 Dalton molecular weight or Euro-Collins solution 160,000 Dalton molecular weight exhibited superior functional and structural results when compared with Euro-Collins solution and Euro-Collins solution 40,000 Dalton molecular weight. Additionally, the least amount of dextran in the lung tissue was found in organs preserved with Euro-Collins solution 160,000 Dalton molecular weight after ischemia and reperfusion., Conclusions: Dextrans are useful additives for lung preservation solutions. However, the size of the molecules is important because dextrans of 160,000 Dalton molecular weight were superior to dextrans of lower molecular weight in our study.

Objective: Euro-Collins solution (EC) is routinely used in lung transplantation. The high potassium of EC, however, may damage the vascular endothelium, thereby contributing to postischemic reperfusion injury. To assess the influence of the potassium concentration on lung preservation, we evaluated the effect of a "low potassium Euro-Collins solution" (LPEC), in which the sodium and potassium concentrations were reversed., Methods: In an extracorporeal rat heart-lung model lungs were preserved with EC and LPEC. The heart-lung blocks (HLB) were perfused with Krebs-Henseleit solution containing washed bovine red blood cells and ventilated with room air. The lungs were perfused via the working right ventricle with deoxygenated perfusate. Oxygenation and pulmonary vascular resistance (PVR) were monitored. After baseline measurements, hearts were arrested with St. Thomas' solution and the lungs were perfused with EC or LPEC, or were not perfused (controls). The HLBs were stored for 5 min or 2 h ischemic time at 4 degrees C. Reperfusion and ventilation was performed for 40 min. At the end of the trial the wet/dry ratio of the lungs was calculated and light microscopic assessment of the degree of edema was performed., Results: After 5 min of ischemia oxygenation was significantly better in both preserved groups compared to the controls. Pulmonary vascular resistance was elevated in all three groups after 30 min reperfusion at both ischemic times. After 2 h of ischemia PVR of the group preserved with LPEC was significantly lower than those of the EC and controls (LPEC-5 min: 184 +/- 65 dynes * sec * cm-5, EC-5 min: 275 +/- 119 dynes * sec * cm * cm-5, LPEC-2 h: 324 +/- 47 dynes * sec * m-5, EC-2 h: 507 +/- 83 dynes * sec * cm-5). Oxygenation after 2 h of ischemia and 30 min reperfusion was significantly better in the LPEC group compared to EC and controls (LPEC: 70 +/- 17 mmHg, EC: 44 +/- 3 mmHg). The wet/dry ratio was significantly lower in the two preserved groups compared to controls (LPEC-5 min: 5.7 +/- 0.7, EC-5 min: 5.8 +/- 1.2, controls-5 min: 7.5 +/- 1.8, LPEC-2 h: 6.7 +/- 0.4, EC: 6.9 +/- 0.4, controls-2 h: 7.3 +/- 0.4)., Conclusions: We thus conclude that LPEC results in better oxygenation and lower PVR in this lung preservation model. A low potassium concentration in lung preservation solutions may help in reducing the incidence of early graft dysfunction following lung transplantation.

Crystalloid perfusates commonly are utilized for lung preservation in extracorporeal small animal lung models. However, the function of these grafts is limited. In a new ex-vivo rat heart-lung model the role of red blood cells added to the crystalloid perfusate was investigated. Heart-lung blocks were rapidly excised (n = 9, each group) and the blocks were connected to the extracorporeal perfusion circuit using Krebs-Henseleit solution (KH) or KH with washed bovine red blood cells (hematocrit 38%) (KHRBC). The lungs were ventilated with room air. The coronary system was perfused via the aortic root with oxygenated perfusate. The lungs were perfused via the right ventricle with deoxygenated perfusate (PO2 15 mm Hg). Venoarterial improvement of oxygenation, pulmonary vascular resistance (PVR), and peak inspiratory pressure (PIP) were continuously monitored for 50 min. At the end of the experiment the wet/dry (W/D) ratio was determined using the mediastinal lung lobe while the remaining lung was used for light microscopic (LM) evaluation. After 30 min of perfusion, lung function was significantly better in the KHRBC group (PVR (KH): 752 +/- 193 dyn*sec*cm-5; (KHRBC): 279 +/- 48 dyn*sec*cm-5; PIP (KH): 31 +/- 3.2 mm Hg; (KHRBC): 25.8 +/- 1.9 mm Hg). In addition, lungs perfused with KHRBC showed significantly less edema than those perfused with KH only (W/D ratio (KH): 7.8 +/- 1.2; (KHRBC) 5.1 +/- 0.6; LM (KH): 3.5 +/- 0.9; (KHRBC): 2.3 +/- 0.8). The use of red blood cells in KH perfusate improved functional and structural integrity.(ABSTRACT TRUNCATED AT 250 WORDS)

In the present report the prevalence, severity, and risk factors of tricuspid valve regurgitation (TR) in 251 heart transplant recipients have been analyzed retrospectively. Tricuspid valve function was studied by color-flow Doppler echocardiogram and annual heart catheterization. The presence or severity of TR was graded on a scale from 0 (no TR) to 4 (severe). Additional postoperative data included rate of rejection, number of endomyocardial biopsies, incidence of transplant vasculopathy, and preoperative and postoperative hemodynamics. The incidence of grade 3 TR increases from 5% at 1 year to 50% at 4 years after transplantation. Multivariate analysis showed rate of rejection and donor heart weight to be significant risk factors. The ischemic intervals as well as the preoperative and postoperative pulmonary hemodynamics did not affect the severity or prevalence of TR. These results indicate that various factors appear to have an impact on the development of TR and that the prevalence might be lowered by a reduction of the number of biopsies performed and when possible, oversizing of donor hearts.

Background: The underlying mechanism of accelerated coronary vasculopathy in cardiac allografts still remains unclear. Our hypothesis was that inhibition of smooth muscle cell proliferation with the somatostatine analogue Angiopeptin may reduce vasculopathy., Methods: Fifty-four patients received Angiopeptin injections (1500 micrograms x three times daily subcutaneously) for 21 days after the operation and three additional injections with every rejection treatment. Angiography was performed yearly, and data were compared with a matched historic control group., Results: Actuarial survival was 85% at 1 year and 80% at 2 years, comparable with our results in general (80%/77%). Forty-six long-term survivors could be followed by coronary angiography. At 1 year, vasculopathy was assessed in nine patients (17%). Of the 18 patients investigated at 2 years thus far, an additional three patients were found to have vasculopathy. In the control group vasculopathy was comparable, being 13% after 1 year and 20% after 2 years. A significantly lower incidence of rejections and lower creatinine values were found in the study group within the entire observation period (p < 0.05)., Conclusions: We conclude that Angiopeptin treatment appears to be safe without significant side effects; it may reduce the number of acute rejections, at least during the first year after heart transplantation. However, the results of the 2-year follow-up in the remaining patients would have to be included in assessing the effect of Angiopeptin. Long-term follow-up will be necessary to decide whether Angiopeptin will be helpful in reducing the incidence of transplant vasculopathy.

The endomyocardial biopsy (EMB) in heart transplant recipients has been considered the "gold standard" for diagnosis of graft rejection (REJ). The purpose of this retrospective study is to develop long-term strategies (frequency and postoperative duration of EMB) for REJ monitoring. Between 1985 and 1992, 346 patients (mean age 44.5 years, female patients = 14%) received 382 heart grafts. For graft surveillance EMBs were performed according to a fixed schedule depending on postoperative day and the results of previous biopsies. In the first year the average number (no.) of EMBs/patient was 20 with 19% positive for REJ in the first quarter, dropping to 7% REJ/EMB by the end of the first year. The percentage of REJ/EMB declined annually from 4.7% to 4.5%, 2.2% and less than 1% after the fifth year. Individual biopsy results in the first 3 postoperative months had little predictive value. Patients with fewer than two REJ (group 1), vs patients with two or more REJ in the first 6 postoperative months (group 2), were significantly less likely to reject in the second half of the first year (group 1: 0.29 +/- 0.6 REJ/patient; group 2:0.83 +/- 1.3 REJ/patient; P < 0.001) and third postoperative year (group 1:0.12 +/- 0.33 REJ/patients; group 2:0.46 +/- 0.93 REJ/patient; P < 0.05). In conclusion, routine EMBs in the first 3 postoperative months have only limited predictive value, however the number of routine EMBs can be drastically reduced later depending on the intermediate postoperative REJ pattern.

Malignant tracheo-esophageal fistulae can be palliated with bifurcate tracheal stents. However, stents must be manufactured according to the individual anatomy. In these instances a foam cuff can result in better sealing of the fistulized area. We present a successful implantation of a bifurcate tracheal stent with foam cuff. To facilitate preoperative planning reconstruction possibilities offered by spiral computed tomography were used.

The toxicity of long-term immunosuppressive therapy has become a major concern in long-term follow-up of heart transplant recipients. In this respect the quality of renal function is undoubtedly linked to cyclosporin A (CsA) drug levels. In cardiac transplantation, specific CsA trough levels have historically been maintained between 250 and 350 micrograms/L in many centers without direct evidence for the necessity of such high levels while using triple-drug immunosuppression. This retrospective analysis compares the incidence of acute and chronic graft rejection as well as overall mortality between groups of patients with high (250 to 350 micrograms/L) and low (150 to 250 micrograms/L) specific CsA trough levels. A total of 332 patients who underwent heart transplantation between October 1985 and October 1992 with a minimum follow-up of 30 days were included in this study (46 women and 276 men; aged, 44 +/- 12 years; mean follow-up, 1,122 +/- 777 days). Standard triple-drug immunosuppression included first-year specific CsA target trough levels of 250 to 300 micrograms/L. Patients were grouped according to their average creatinine level in the first postoperative year (group I, < 130 mumol/L, n = 234; group II, > or = 130 mumol/L, n = 98). The overall 5-year survival excluding the early 30-day mortality was 92% (group I, 216/232) and 91% (group II, 89/98) with 75% of the mortality due to chronic rejection. The rate of rejection for the entire follow-up period was similar in both groups (first year: group I, 3.2 +/- 2.6 rejection/patient/year; group II, 3.6 +/- 2.7 rejection/patient/year; p = not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

Palliative intubation of the esophagus for a malignant tracheoesophageal fistula is often complicated by difficulty in obtaining a tight seal. We have overcome the problem in three instances by placing a bifurcated, foam-cuffed stent in the trachea.

Ischemic airway complications after lung transplantation remain a significant problem despite the use of bronchial omentopexy. Clinical observations suggest that enhancement of vascular ingrowth could possibly increase the efficacy of a bronchial omental flap. This study was therefore designed to investigate whether basic fibroblast growth factor can enhance blood supply of an ischemic airway by acceleration of vascular ingrowth in a rabbit autotransplant model. Segments of the trachea were harvested and transplanted into a subcutaneous pouch. The animals were randomly assigned to one of four groups: group I, no omentopexy; group II, omentopexy; group III, omentopexy and fibrin glue; or group IV, omentopexy and fibrin glue enriched with 2.5 micrograms basic fibroblast growth factor. After 14 days the animals were sacrificed. The extent of perfusion was investigated by means of radioactive microspheres. The morphology of the tracheal segments was investigated in a blinded fashion macroscopically, by means of light microscopy, and by means of scanning electron microscopy. The radioactivity measurements revealed a significantly increased perfusion of group IV (77% +/- 42%) as compared with groups I (17% +/- 13%) and III (20% +/- 16%). By macroscopic and light microscopic assessment, the epithelial integrity of group IV was significantly improved compared with groups I and II. At electron microscopy the integrity of group IV was significantly superior to all remaining groups. We conclude that a deposit of basic fibroblast growth factor and fibrin glue appears to increase revascularization of an ischemic airway from omentum and thus results in improved epithelial preservation of a tracheal autograft.

Protection of the failing right ventricle (RV) in the surgical treatment of massive pulmonary embolism is a keystone for myocardial recovery. This study evaluated whether cardioplegia should be used or avoided. In a modified Langendorff rat heart model pulmonary embolism was simulated by afterload elevation (20 cm H2O) for 30 min. Hearts were arrested with cardioplegic solutions [St. Thomas Hospital (ST); University of Wisconsin (UW); oxygenated Krebs-Henseleit-Potassium (KHP)] and stored for 10 min or were allowed to beat empty (NoCP) for 15 min. After reestablishing of baseline conditions groups were measured for 60 min. Cardiac index (CI) decreased in all groups to 20% during afterload elevation. Group NoCP showed 68 and Group ST 65% recovery after 10 min and deteriorated after 30 min. After 60 min CI was 37 (ST) and 39% (NoCP). UW and KHP showed a significantly better recovery (KHP 100%; UW 88%). At 60 min CI decreased to 60 (KHP) and 64% (UW), but was still significantly higher than corresponding values of NoCP and ST. Following increased pulmonary afterload cardioplegia with UW or KHP solution is beneficial for RV recovery. The composition of the cardioplegia is obviously important and needs further study.

Refixation of dissected aortic layers with gelatin-resorcin-formaldehyde/glutaraldehyde (GRFG) adhesive represents a new option in the surgical treatment of aortic dissection. Because of its ability to reinforce the delicate structures of the acutely dissected aortic wall, GRFG has been used increasingly in recent years. However, the biomechanical properties of the adhesive are still unclear, and little is known regarding the optimal mode of its application. In an ex vivo study, aortic specimens from sheep were glued with warm (45 degrees C) adhesive under wet and dry conditions and submitted to defined degrees of compression (5 Newtons [N], 20 N). Bonded specimens were retracted to assess tensile strength and elasticity compared with two reference adhesives: cyanoacrylate gel and fibrin glue. Gelatin-resorcin-formaldehyde/glutaraldehyde and cyanoacrylate gel showed similar results at 5 N. Both provided better adhesion when applied under dry conditions (GRFG 5 N: dry, 3.5 +/- 1.6 N/cm2; wet, 1.4 +/- 1.0 N/cm2; cyanoacrylate gel 5 N: dry, 4.8 +/- 1.8 N/cm2; wet, 3.2 +/- 1.3 N/cm2). At 20 N, GRFG tensile strength was significantly increased for either condition compared with values at 5 N (GRFG 20 N: dry, 17.1 +/- 4.2 N/cm2; wet, 4.8 +/- 1.8 N/cm2). Fibrin glue demonstrated only weak adhesive properties even under dry conditions (fibrin glue 5 N: dry, 0.8 +/- 0.3 N/cm2). Gelatin-resorcin-formaldehyde/glutaraldehyde has good adhesive properties both in wet and dry tissue. Bonding capacity can be substantially increased when applied on dry surfaces and at increased pressures.

Fulminant pulmonary embolism associated with cardiac arrest has an extremely high mortality. The feasibility of pulmonary embolectomy initiated during resuscitation is still under discussion. Between January 1975 and October 1992, embolectomy was performed in 34 patients, 21 to 79 years of age. Diagnosis was established primarily by indirect parameters (medical history, ECG, blood gas analyses, Swan-Ganz catheter in 22 cases). Only in 12 instances, imaging techniques as angiography, ventilation perfusion mismatch, and transesophageal echocardiography were performed. Fifteen patients did not require resuscitation (group A); 6 had to be resuscitated and underwent surgery after reestablishing circulation with catecholamines (group B); 13 patients were connected to extracorporeal circulation during continuous cardiopulmonary resuscitation (30 to 210 minutes) (group C). Embolectomy was performed using extracorporeal circulation with the heart beating (n = 8), or fibrillating (n = 15), or using cardioplegia (n = 11). Twenty-two patients received a caval clip or ligature at the end of the procedure. Fifteen patients (44%) died early postoperatively. The mortality rates for groups A, B, and C were 33%, 66% and 46%, respectively. Nine patients died of right heart failure, 4 of brain death, and 2 of septical complications. Of the surviving patients, only one had ischemic brain damage. In two cases a recurrent pulmonary embolism occurred after a follow-up of 16 years (mean follow-up 4.9 years). We conclude, that even with subtotal obstruction of the pulmonary artery, effective cardiopulmonary resuscitation with maintenance of uncompromised brain function is possible. In emergency situations, the decision to operate may be based only on clinical features without imaging diagnostic procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

The indication for coronary bypass surgery in the elderly has been dramatically expanded in recent years. The results, however, are often contradictory. 1,538 consecutive patients undergoing cardiac surgery were divided into two groups by their age at the time of operation: younger than 75 years (n = 1,480) and 75 years and older (n = 58). These groups were compared with regard to influencing factors of early and late mortality, morbidity, and quality of life. Preoperatively, the clinical condition of the group greater than or equal to 75 years was significantly worse than the condition of the group less than 75 years (NYHA IV: greater than or equal to 75 years: 63.8%; less than 75 years: 31.9%). Cerebrovascular diseases occurred more often in the patients greater than or equal to 75 years (stroke or transient ischemic attack: greater than or equal to 75 years: 8.6%; less than 75 years: 2.3%). The necessity of carotid reconstruction prior to coronary surgery was significantly higher in the patients greater than or equal to 75 years: (greater than or equal to 75 years: 5.2%; less than 75 years: 1.5%). Diabetes mellitus could be observed in 19.0% of the patients greater than or equal to 75 years and in 10.1% of the patients less than 75 years. The preoperative ejection fraction was similar in both groups. Cardiopulmonary bypass time and crossclamping time of the aorta did not differ significantly. Both groups received approximately the same number of distal coronary anastomoses. Rethoracotomy due to hemorrhage had been observed more often in the older group (greater than or equal to 75 years: 8.6%; less than 75 years: 4.5%).(ABSTRACT TRUNCATED AT 250 WORDS)