Biomedical subjects
Publications and source records attributed to Ulf Lockowandt.
Vacuum-assisted closure therapy is a recently introduced technique for treatment of deep sternal wound infections after cardiac surgery. We present five cases of vacuum-assisted closure therapy-related major bleeding complications due to rupture of the right ventricle. This potentially lethal complication may be avoided by covering the heart with protective layers of paraffin gauze dressings.
OBJECTIVE: The number of elderly patients who require aortic valve replacement is growing, as is the increase of complicating factors, such as previous coronary bypass grafting and atherosclerotic disease of the ascending aorta. An uncommon surgical option to aortic valve replacement is the apicoaortic valved conduit. In this article the techniques and outcomes of 13 cases of apicoaortic valved conduit insertions in high-risk patients are described. METHODS: From 2002 through 2005, 13 patients (mean age, 75 +/- 8.7 years; 8 men) with severe calcific aortic stenosis had insertions of an apicoaortic valved conduit because of a porcelain aorta (n = 4), previous coronary bypass grafting (n = 6), or both (n = 3). The off-pump technique was used in 9 patients, and a heparinized miniextracorporeal circulation system was used in 4 patients. Follow-up time was 6 to 33 months. RESULTS: Mean intensive care stay was 2 +/- 2.7 days, and mean hospital stay was 12 +/- 8 days. The 30-day mortality was 15% (2 patients; postoperative days 3 and 28, both caused by myocardial infarction). Mortality later than 30 days postoperatively was 23% (3 patients; postoperative day 45 caused by bilateral pulmonary bleeding because of pneumonia, postoperative day 56 caused by myocardial infarction, and postoperative day 81 caused by pneumonia). The remaining 8 patients were doing well, all in New York Heart Association class I or II at follow-up, with echocardiography showing a low gradient over the valved conduit. CONCLUSIONS: The apicoaortic valved conduit in high-risk patients undergoing aortic valve replacement remains a feasible option, with a substantial potential for technical development and progress.
OBJECTIVE: Many surgeons do not deal with atrial fibrillation or choose modifications of the maze procedure when performing additional cardiac surgery. The Cox maze III procedure as an adjunct to other sometimes very complex cardiac surgery was examined. DESIGN: 40 patients (27 men), 36 to 76 years, underwent a full Cox maze III operation in combination with other cardiac surgery, reflecting the case mix of a modern practice. Permanent fibrillation was presented by 82%, the others suffering from persistent or paroxysmal fibrillation. Pre-operative duration of atrial fibrillation was 0.5 to 39 years. Follow-up was 22 to 82 months. RESULTS: The 30-day mortality was 2.5%; there was one case of intra aortic balloon-pump, two re-operations because of bleeding (5%), and one re-operation because of systolic anterior motion of the anterior mitral leaflet. Follow-up was 95% complete. Late mortality was 2.5%. Five patients (14%) required postoperative pacemakers. Freedom of atrial fibrillation was 97%. CONCLUSION: The addition of the Cox maze III procedure to other sometimes very complex cardiac surgery is safe and efficient in controlling atrial fibrillation.
The effects of combined aortic valve replacement, coronary bypass surgery, and passive containment surgery in a patient with long-standing aortic regurgitation and marked ventricular dilatation are described. After surgery there was a rapid decrease in left ventricular size and maintained ventricular function.
OBJECTIVE: To evaluate the possible beneficial echocardiographic, functional and quality of life improving effects of passive containment surgery using the CorCap Cardiac Support Device in heart failure patients with dilated cardiomyopathy. DESIGN: Eight patients with dilated cardiomyopathy subjected to cardiac surgery received the Cardiac Support Device. Patients with ischemic cardiomyopathy (n = 4) underwent coronary artery bypass surgery receiving one to three bypass grafts. In the idiopathic cardiomyopathy group (n = 4) mitral valve plasty was performed in two patients while two patients received the Cardiac Support Device only. RESULTS: All patients survived the surgery and were discharged to home. There was a gradual, sustained improvement in cardiac dimensions (left ventricular end-diastolic diameter, left ventricular end-systolic diameter) and functional improvement (ejection fraction, 6-min walk, NYHA functional class) as well as quality of life. These beneficial effects developed more rapidly and more extensively in the idiopathic cardiomyopathy group. CONCLUSION: Addition of the Cardiac Support Device to conventional cardiac surgery, or applied alone, is safe and simple. The device seems to reverse ventricular dilatation and improve functional capacity and well-being of heart failure patients with dilated cardiomyopathy. Further studies will delineate what patient population will best benefit from passive containment surgery using the CorCap Cardiac Support Device.
OBJECTIVE: To determine the tissue content and endothelin-receptor characteristics of endothelin-1 in the radial artery in relation to the internal mammary artery. DESIGN: Endothelin-1 content was quantified in the radial artery and the internal mammary artery. Both arteries were exposed to endothelin-1 and agonists of the endothelin A and B receptors. RESULTS: The highest level of endothelin-1 was found in the radial artery. Endothelin-1 contracted both arteries. The contraction was sensitive to endothelinA-receptor agonism and enhanced in both arteries by inhibition of prostacyclin and nitric oxide formation. In the internal mammary artery the endothelinB-receptor agonist caused an endothelinA-receptor sensitive contraction augmented by inhibition of nitric oxide and prostacyclin. However, in the radial artery this contraction was only observed in the presence of inhibition of nitric oxide and prostaglandin. CONCLUSION: The highest endothelin-1 content was found in the radial artery. The functional effects of endothelin-1 in the radial artery were similar to that in the internal mammary artery, mediated by predominantly endothelinA-receptor activation causing vasoconstriction. Selective endothelinA-receptor blockade may prove beneficial in preventing graft spasm in the radial as well as the internal mammary artery.
The splanchnic area is of considerable interest in different types of shock. To characterize the metabolic changes in the splanchnic region in response to different types of shock we used a model where shock-induced metabolic changes in the splanchnic region were studied by the use of intravasal microdialysis. 23 anesthetized domestic pigs were randomized into four groups: Group I, serving as controls (n = 5); Group II, mesenteric ischemia for 180 followed by 120 min of reperfusion (n = 5); Group III, endotoxin shock for 5 h (n = 5); and Group IV, hemorrhagic shock for 180 min followed by re-transfusion of shed blood (n = 8). Microdialysis catheters were placed in the left femoral artery, portal vein and a small ileal mesenteric vein. Samples of the perfusate were continuously collected in micro-vials and analyzed for glucose, lactate, pyruvate and glycerol. In gut ischemia and endotoxin shock the outflow-pattern of lactate, lactate/pyruvate ratio and glucose in the mesenteric vein differed significantly from controls and hemorrhage whereas an increase in glycerol was only noted in the ischemic group. The most prominent differences were detected in lactate/pyruvate ratio, a marker of tissue ischemia with the most pronounced changes during mesenteric ischemia/reperfusion. During endotoxin shock increases in microdialysate metabolites were only noted in the splanchnic region suggesting a specific vulnerability in the region. Studying the lactate/pyruvate ratio may provide additional information when interpreting increased blood lactate levels. In addition glycerol may prove to be a useful marker of splanchnic ischemia. Intravasal microdialysis represents a potentially useful method for monitoring regional metabolic events.
A novel application of microdialysis was studied, in which myocardial outflow of amino acids and purines was monitored by intravasal microdialysis in the myocardial venous outflow during ischemia and reperfusion. Microdialysis catheters were introduced into the great cardiac vein, pulmonary artery, and external jugular vein in 20 anesthetized pigs. The left anterior descending artery was occluded in four groups of pigs for 0, 10, 15, and 60 min. Ischemia was followed by 120 min of reperfusion. Microdialysis samples were analyzed for taurine, aspartate, glutamate, hypoxanthine, inosine, and guanosine. Myocardial infarction developed when ischemia exceeded 10 min. Taurine, aspartate, inosine, and guanosine increased early in the great cardiac vein during ischemia. We found the outflow patterns of amino acids and purines to be graded in response to different lengths of ischemia. In this study we have demonstrated a graded outflow of amino acids and purines in response to ischemia and a positive correlation between infarct size and myocardial outflow of amino acids and purines. This could be of value in a clinical setting to quantify the extent of myocardial damage.
BACKGROUND: Diverse results exist regarding myocardial release of endothelin after coronary artery bypass grafting. Because endothelin may be involved in regulation of coronary blood flow, postoperative endothelin-blockade could influence the surgical outcome. In this study, we have evaluated the cardiac outflow of endothelin and effects on coronary flow by endothelin-blockade immediately after completion of the coronary bypass grafting. METHODS: Thirty patients were subjected to infusions of endothelinA blocker (BQ-123, 260 nmoL/min for up to 30 minutes) or endothelinA blocker and endothelinB blocker (BQ-123 and BQ-788, 260 and 250 nmol/min, respectively, for up to 30 minutes) into a veingraft anastomosed to a coronary vessel, and the coronary blood flow was measured. Plasma levels of endothelin from the coronary sinus and the periphery were determined. RESULTS: There were no significant changes in flow caused by endothelinA blockade alone or in combination with endothelinB blockade. There were no immediately increased levels of endothelin after surgery or after infusions of the endothelin blockers. CONCLUSIONS: Endothelin blockade does not influence the immediate perioperative myocardial blood flow after coronary bypass grafting. There is no significantly increased myocardial outflow of endothelin, and endothelin does not have any influence on the basal tone of the coronary vessels in the early phase after coronary bypass grafting.
OBJECTIVES: The aim of this study was to determine the plasma and pericardial levels of endothelin-1 (ET-1) and its precursor big endothelin-1 (Big ET-1) in patients with unstable and stable angina prior to and following coronary bypass surgery. To further investigate the content of ET-1, tissue levels were studied in the internal mammary artery (IMA) in patients with stable and unstable angina pectoris. Finally, the difference in reactivity of the IMA to ET-1 and Big ET-1 in stable and unstable patients was evaluated. METHODS: Plasma and pericardial levels of ET-1 and Big ET-1 were determined with radioimmunoassay in 81 patients (33 unstable) immediately before coronary bypass surgery, and at 6, 14, 40 and 64 h following the procedure. Specimens of the distal IMA from 12 patients (six unstable) were collected at the beginning of surgery for determination of tissue levels of ET-1. Additionally, distal internal mammary arteries were obtained from another 24 patients (12 unstable). These vessels were mounted in organ baths for functional studies on vascular reactivity to ET-1 and Big ET-1. RESULTS: The peripheral plasma levels of ET-1 in unstable patients were significantly lower in patients with unstable angina compared with patients with stable angina pectoris at all points of measurement. The levels of Big ET-1 were significantly higher pre-operatively in the unstable group, but decreased to similar levels to those of stable patients following coronary bypass grafting. There was no difference in ET-1 tissue content in the IMA between the patients. ET-1 and Big ET-1 caused an endothelin(A) (ET(A))-receptor blocker sensitive, concentration-dependent contraction of the IMA obtained from stable as well as unstable patients. CONCLUSIONS: It is concluded that unstable angina pectoris is associated with an increased ET-1 turnover. This increased turnover may participate in the local regulation of coronary vascular tone with subsequent influence of the condition of the patients. The present investigation also implies that ET(A)-blockade may be useful as an additional pharmacological principal in the treatment of unstable angina pectoris prior to revascularization, as well as to prevent post-operative arterial graft spasm.
OBJECTIVE: A novel application of microdialysis is studied where myocardial metabolism is semi-continuously monitored in the myocardial venous outflow during ischemia and reperfusion. DESIGN: Microdialysis catheters were introduced into the great cardiac vein, the pulmonary artery, and the right external jugular vein in 20 anesthetized pigs. The left anterior descending artery was occluded in four separate groups of pigs for 0, 10, 15, and 60 min, respectively. Ischemia was followed by 120 min of reperfusion. Microdialysis samples were collected every 10-20 min and analyzed for lactate, pyruvate, glycerol, glutamate, and glucose. RESULTS: Myocardial infarction was observed after 15 min of ischemia. Metabolic changes were observed only in the great cardiac vein. Lactate increased early during ischemia. After 60 min of ischemia an increase of the lactate/pyruvate ratio and glutamate was observed. Glycerol was progressively released during prolonged ischemia. Myocardial infarction resulted in an additional release of glycerol early in reperfusion. CONCLUSION: Intravasal microdialysis is a semi-continuous method to monitor myocardial metabolism and tissue damage during ischemia and reperfusion.
A case of a 30-year-old woman with a double-barrelled aorta misdiagnosed as asthma is presented. The patient was significantly improved after surgical treatment but a degree of airway symptoms persisted. She was further investigated and diagnosed with tracheomalacia. The paediatric experience with managing tracheomalacia is briefly reviewed and recommendations for the treatment of the rare adult cases are made. Our report emphasises the importance of early diagnosis and treatment of aortic arch abnormalities.