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Biomedical subjects

J Cremer

Publications and source records attributed to J Cremer.

At least 55 records · Page 3Linked to original sources
PubMed1998

Thoracic computed tomography prior to redo coronary surgery.

OBJECTIVE: Median resternotomy in coronary redo surgery represents a specific risk for injury of adjacent retrosternal structures. Aiming at improved preoperative evaluation of retrosternal structures, computed tomography (CT) techniques were routinely applied in redo cases. METHODS: Of 99 patients undergoing coronary reoperations since April 93, thoracic CT scans were retrospectively analyzed for retrosternal vicinity of cardiovascular structures, condition of the ascending aorta and structural abnormalities of the sternum. RESULTS: The minimal median distance between the posterior sternum surface and the anterior aortic wall was measured at 1.9 +/- 0.9 cm, whereas the mean closest distance to the anterior right ventricular wall was 0.4 +/- 0.5 cm. In 28 cases, the distance between sternum and aorta was smaller than or equal to 1 cm. No measurable distance between the sternum and the right ventricle was noted in 41 patients. Calcification of the ascending aorta became obvious 56 times. With respect to potential injury of the ascending aorta or the right ventricle, a safe reentry by resternotomy was facilitated in all cases. However, following complete sawing, the innominate vein became injured during retrosternal dissection in two cases. Preventive femoral vessel exposure was not performed and urgent femoral cannulation (n = 1) was infrequent. CONCLUSIONS: Thoracic CT scanning prior to redo coronary surgery allows for detailed assessment of retrosternal relations and facilitates reopening of the sternum. Preventive femoral vessel exposure and lateral thoracotomies may be avoidable in many cases.

Aortography↗
PubMed1998

Intrapericardial pheochromocytoma.

Pheochromocytoma are catecholamine-secreting tumors occurring in less than 1% of the hypertensive population. Even though more sensitive methods have facilitated the diagnosis of intrathoracic paragangliomas they still remain extremely rare. This study reports a patient with a cardiac pheochromocytoma in whom the tumor was located on the outside of the roof of the left atrium and involved the left main coronary artery. Due to this anatomy the resection of the tumor required a cardio-pulmonary bypass and transsection of the pulmonary artery. The postoperative course was uneventful and the patient could be discharged without significant hypertension.

Cardiopulmonary Bypass↗
PubMed1998

Ischemic preconditioning as an adjunct to crystalloid or blood cardioplegia for myocardial protection in routine coronary surgery.

Experimental preconditioning is commonly regarded as a powerful protective phenomenon in case of subsequent ischemia. However, little is known about the applicability of preconditioning as an adjunct to cardioplegic myocardial protection in routine coronary surgery. For this reason, a prospective clinical study (611995 to 4/1996) was initiated to evaluate normothermic ischemic preconditioning prior to crystalloid or cold blood cardioplegic arrest. Preconditioning was performed in two cycles of 5 min ischemia and 10 min reperfusion. Four groups of 7 patients each were compared regarding release of troponin T, creatine kinase-myocardial isoform (CK-MB), lactate, and total CK in coronary sinus effluents over a 12-hour period. In the absence of perioperative myocardial infarction, there were no significant differences in these ischemic and metabolic parameters. Unexpectedly, the heed of postoperative pharmacological inotropic support was greater after preconditioning. These results may indicate that ischemic preconditioning as an adjunct to cardioplegic arrest may be associated with impairment of left-ventricular contractility, thus even exerting potentially detrimental functional effects. Overall, the proven beneficial effects of experimental preconditioning seem not to be directly transferable into the clinical settings.

Aged↗
PubMed1997

[Antibiotic resistance of enterococci in Germany].

BACKGROUND: The resistance of enterococci against various antimicrobial substances including vancomycin has increased markedly. Since 1989 in the USA in particular high resistance rates against vancomycin have been observed but very few surveillance have been published in Europe. Therefore, we conducted a multicenter study in Germany to obtain information about the incidence and distribution of vancomycin and/or high-level aminoglycoside-resistant enterococci. METHODS: A total of 2046 enterococcal isolates were identified and susceptibility-testing was performed according to international guidelines. RESULTS: A total number of 90.5% of the enterococcal isolates were identified as Enterococcus faecalis and 7.8% was Enterococcus faecium. Resistance against ampicillin was detected in 56.6% of the Enterococcus faecium isolates, however, in only one Enterococcus faecalis isolate. High-level resistance against gentamycin or streptomycin was observed in 7.3% and 24.8% of the isolates, respectively. Twelve isolates showed resistance against vancomycin, however, cross resistance with teicoplanin was found in only two isolates. CONCLUSION: The rate of resistance of enterococci in Germany is still considerably lower than in the United States. Previous vancomycin therapy has been implemented as a risk factor for colonization or infection with vancomycin-resistant enterococci. Continued vigilance, decreased use of vancomycin and strict enforcement of infection control measures are appropriate measures to control the growing problem of resistant enterococci.

Ampicillin Resistance↗
PubMed1997

Previous open heart operation: a contribution to impaired outcome after cardiac transplantation?

BACKGROUND: There is still debate about whether previous cardiac operations are a risk factor for patient outcome after cardiac transplantation. As waiting lists for cardiac transplantation increase, adverse outcome criteria should be identified. METHODS: To assess this problem, we retrospectively analyzed 53 patients with previous cardiac operations before heart transplantation and compared them with 53 control patients matched for sex and age. Patient groups were analyzed regarding their preoperative, intraoperative, and postoperative variables and survival. RESULTS: Ischemic times were comparable in both groups, but the duration of the operation was significantly longer in the study group (206.5 +/- 62.5 minutes, versus 156.0 +/- 36.7 minutes in controls; p < 0.05). In addition, postoperative blood loss was greater for the patients with previous cardiac operations (1,360 +/- 260 mL, versus 730 +/- 310 mL for controls; p < 0.01). Postoperatively, the rate of rejection episodes and the incidence of graft atherosclerosis were comparable within the first 2 years. However, survival was significantly reduced in the study group (60.1%) after 4 years (versus 83.1% for controls; p < 0.05). CONCLUSIONS: Heart transplantation in patients with previous cardiac operations will lead to an impaired overall outcome. In addition, these patients have more postoperative complications.

Cardiac Catheterization↗
PubMed1997

Off-bypass coronary bypass grafting via minithoracotomy using mechanical epicardial stabilization.

BACKGROUND: Minimally or less invasive surgical coronary revascularization has gained increasing interest along with new techniques and devices designed for easier and safer procedures. Until recently, it appeared questionable whether grafting techniques with avoidance of cardiopulmonary bypass techniques would allow adequate results compared with conventional techniques using cardioplegic arrest. METHODS: Since June 1996, minimally invasive direct coronary artery bypass grafting procedures without cardiopulmonary bypass were intended in 24 patients (19 male, 5 female; age, 60.5 +/- 10.5 years) applying a special system (CardioThoracic Systems, Inc) for internal mammary artery access and epicardial surface stabilization approaching through an anterolateral minithoracotomy. Neither video-assisted preparation nor additional pharmacologic stabilization was applied. Concomitant risk factors and associated comorbidity were frequent. RESULTS: The procedure was completed in 23 patients, grafting the left anterior descending coronary artery (n = 21) or diagonal branches (n = 3, 1 sequential) as scheduled. In 1 case with internal mammary artery dissection, cardiopulmonary bypass and sternotomy became necessary. Simultaneous carotid endarterectomy was performed in 1 patient. There were two episodes of intraoperative ventricular fibrillation; no other major complications occurred. Postoperative evaluation was obtained in 16 patients (15 by angiography, 1 by Doppler echocardiography) so far and revealed adequate graft function and patency. CONCLUSIONS: Using specially designed instruments for internal mammary artery access and epicardial surface stabilization, minimally invasive direct coronary artery bypass grafting procedures via a minithoracotomy avoiding cardiopulmonary bypass techniques may be applied safely and successfully, even in increased risk constellations.

Cardiopulmonary Bypass↗
PubMed1997

Influence of bicaval anastomoses on late occurrence of atrial arrhythmia after heart transplantation.

BACKGROUND: The standard technique for orthotopic heart transplantation includes right and left atrial anastomoses, which potentially disturb the integrity of the donor atria. Consequently, electrophysiologic abnormalities such as atrial flutter and fibrillation may occur even late after heart transplanation. METHODS: Over a 3-year period, 39 heart transplantations were performed using a standard right atrial anastomosis (group A), and 40 were done using bicaval anastomoses (group B). In each group, data of 30 consecutive patients with a minimum follow-up of 9 months were reviewed retrospectively to assess the incidence of atrial arrhythmia after hospital discharge. RESULTS: Early postoperatively, there was no difference in the duration of temporary pacemaker requirement and incidence of permanent pacemaker implantation (group A, 7%; group B, 7%; not significant) between the two groups. In 12 patients in group A (40%), 16 episodes of atrial flutter and fibrillation were detected 20 to 205 days after heart transplantation. In group B, 1 patient (4%) suffered from atrial fibrillation on day 116 after the operation (p < 0.001). CONCLUSIONS: Preservation of the integrity of the right donor atrium by construction of bicaval anastomoses results in a significantly decreased incidence of atrial flutter and fibrillation after heart transplantation when compared with the standard technique.

Adult↗
PubMed1997

Ischemic preconditioning prior to myocardial protection with cold blood cardioplegia in coronary surgery.

OBJECTIVE: Encouraging results on myocardial preconditioning in experimental models of infarction, stunning or prolonged ischemia raise the question whether preconditioning techniques may enhance conventional cardioplegic protection used for routine coronary surgery. METHODS: A prospective clinical trial was conducted to investigate the effect of additional ischemic normothermic preconditioning prior to cardioplegic arrest applying cold blood cardioplegia in patients scheduled for routine coronary surgery (3 vessel disease, left ventricular ejection fraction > 50%). Two cross clamp periods of 5 min with the hearts beating in sinus rhythm were applied followed by 10 min of reperfusion, each (n = 7, group I). Inducing moderate hypothermia cold blood cardioplegia was delivered antegradely. In control groups, cold intermittent blood cardioplegia (n = 7, group II) was used alone. Coronary sinus effluents were analyzed for release of creatine kinase (CK), CK-MB, lactate, and troponin T at 1, 3, 6, 9, and 12 h. In addition, postoperative catecholamine requirements were monitored. RESULTS: The procedure was tolerated well, and no perioperative myocardial infarction in any of the groups studied occurred. Concentrations of lactate tended to be higher in group I, but this difference was not significant. In addition, no significant differences for concentrations of CK, CK-MB, and troponin T were found. Following ischemic preconditioning an increased dosage of dopamine was required within the first 12 h postoperatively (group I: 2.63 +/- 1.44 microg/kg/min, group II: 0.89 +/- 1.06 microg/kg/min). CONCLUSIONS: Combining ischemic preconditioning and cardioplegic protection with cold blood cardioplegia does not appear to ameliorate myocardial protection when compared to cardioplegic protection applying cold blood cardioplegia alone. Inversely, contractile function seemed to be impaired when applying this protocol of ischemic preconditioning.

Biomarkers↗
PubMed1997

[Minimal invasive bypass operations on the beating heart and using mechanical stabilization of the heart surface].

Different minimally invasive techniques are currently being controversially discussed among cardiac surgeons. For revascularization of anterior myocardial vessels, off-bypass procedures were performed in 64 cases through an anterolateral submammary minithoracotomy using the left internal mammary artery. Application of mechanical epicardial stabilization facilitated adequate exposure of the anastomosis and resulted in good patency rates and a low number of complications.

Aged↗
PubMed1997

[Wound infections after heart surgery interventions--a cost analysis].

Decreasing financial resources in the health care system require effective cost management. For this reason and due to special modalities of reimbursement regulations for open heart procedures, we analyzed the extent of additional costs caused by subsequent deep wound infections requiring surgical revision. The real costs of 12 consecutive cases of sternal infections out of a total of 1,124 open heart procedures in 1996 were assessed and differentiated.

Cardiac Surgical Procedures↗
PubMed1996

Therapy for lung failure using nitric oxide inhalation and surfactant replacement.

Nitric oxide inhalation and surfactant replacement therapy are relatively new concepts in the treatment of respiratory failure due to hypoxia and reperfusion injury after lung transplantation. We report on a patient in whom reperfusion injury of the lung developed after resuscitation and implantation of a biventricular assist device for sudden cardiac arrest. Lung failure developed within 12 hours after implantation of the biventricular assist device. Lung function was reestablished using combined therapy of nitric oxide and surfactant. Heart transplantation was performed successfully thereafter. This case indicates the potential role of a combined therapy of nitric oxide and surfactant in acute hypoxic lung failure.

Adult↗
PubMed1996

Systemic inflammatory response syndrome after cardiac operations.

BACKGROUND: A systemic inflammatory response after open heart operation may be responsible for hyperdynamic circulatory instability and organ dysfunction. To what extent mediator release is involved needs to be clarified. METHODS: Ten patients with postoperative hyperdynamic circulatory dysregulation (group I) requiring application of alpha-constrictors and 10 patients with routine cardiac procedures and stable postoperative hemodynamic indices (group II) were analyzed for mediator release and metabolic and hemodynamic changes until the third postoperative day. RESULTS: Group I patients showed a significantly increased cardiac index and decreased systemic vascular resistance after bypass (cardiac index, group I: 5.2 +/- 1.2 L.min-1.m-2, group II: 2.5 +/- 1.6 L.min-1.m-2; systemic vascular resistance, group I: 495 +/- 204 dyne.s. cm-5, group II: 1,356 +/- 466 dyne.s.cm-5) and at 3 hours (cardiac index, group I: 4.4 +/- 0.8 L.min-1.m-2, group II: 2.9 +/- 0.6 L.min-1.m-2; systemic vascular resistance, group I: 567 +/- 211 dyne.s.cm-5, group II: 1,053 +/- 273 dyne.s.cm-5). Significantly higher serum levels of interleukin-6 were assessed in group I (postbypass, group I: 6,812 +/- 9,293 pg/mL, group II: 295 +/- 303 pg/mL; 3 hours, group I: 3,474 +/- 5,594 pg/mL, group II: 286 +/- 296 pg/mL). Concentrations of elastase, tumor necrosis factor, soluble tumor necrosis factor receptor, and interleukin-8 were elevated in group I (not significant). Early postoperative levels of soluble E-selectin and soluble intercellular adhesion molecule were also higher in group I (not significant). Continuously increased levels of endotoxin could be detected in only 3 of 10 patients in group I. Severe lactic acidosis (> or = 5 mmol/L) occurred in group I only. CONCLUSIONS: Postoperative hyperdynamic instability after open heart operations appears to be associated with a certain pattern of mediator release. In particular, interleukin-6 appears to be involved in circulatory dysregulation and metabolic derangement.

Acidosis, Lactic↗
PubMed1996

Evaluation of a soluble E-selectin enzyme-linked immunosorbent assay under posttraumatic conditions.

The up-regulation of E-selectin, one of the adhesion molecules on the endothelium, is an important event in the mediation of the inflammatory response. Because the presence of E-selectin cannot be determined directly in vivo except by invasive biopsy techniques, the only available information concerning its activity is the serum level of the soluble form. Therefore we tried to measure soluble E-selectin levels in trauma and sepsis situations, where endothelial activation is supposed to occur. We have investigated the soluble E-selectin levels in a group of patients undergoing the trauma associated with cardiac surgery and the use of extracorporeal circulation, some of whom developed a systemic inflammatory response syndrome (SIRS). We have also confirmed that our enzyme-linked immunosorbent assay (ELISA) will detect the levels of soluble E-selectin that are produced as a result of the exposure of cultured human umbilical endothelial cells to even low levels of endotoxin. The data presented in this paper indicate that in patients with SIRS after extracorporeal circulation, the levels of circulating soluble E-selectin are numerically higher but---at least in this group of patients---not statistically significantly different from the levels in patients who have undergone the surgery. These results suggest that the measurement of serum levels of soluble E-selectin is not a reliable method for monitoring the onset of SIRS in patients having undergone surgical trauma, although we have confirmed that our ELISA will detect the levels of soluble E-selectin that are produced as a result of the exposure of cultured human endothelial cells to even low levels of endotoxin.

Adult↗
PubMed1996

Thoracoscopic creation of a pericardial window for recurrent pericardial effusion after heart transplantation.

A 56-year-old man underwent orthotopic heart transplantation (Htx) for dilative cardiomyopathy. The postoperative course was uneventful despite the appearance of pericardial effusions during the first 6 months, which required repeated drainage therapy. Six months postoperatively a pericardial window was created using a thoracoscopic approach via the right pleural cavity. The course after this intervention was uncomplicated and there was no recurrence of the pericardial effusion during 18 months of follow-up.

Endoscopy↗
PubMed1996

Early postoperative flow rates after internal thoracic artery grafting for the left coronary artery system.

OBJECTIVE: The low perioperative flow rates of internal thoracic artery (ITA) conduits have been regarded as a limitation of their use in critical coronary situations with a high myocardial blood demand. To clarify whether these restrictions are justified, early postoperative flow rates were determined. METHODS: Following bilateral ITA grafting, 48 of 106 patients (April 1993-September 1994) underwent recatheterization. Subsequent to control angiography between days 8 and 12, 20 of these patients were studied by intravascular Doppler techniques applied for ITA grafts supplying the left anterior descending artery (LAD) and branches of the circumflex system (CX) (n = 20). Doppler spectral analysis allowed for determination of the average peak velocity and diastolic-systolic velocity ratio. Vascular diameters were assessed by simultaneously performed quantitative angiography and mean flow rates were calculated. All parameters were recorded at rest and following selective stimulation with nitroglycerin (0.2 mg) and papaverine (12.5 mg) to evaluate the graft flow capacity. RESULTS: Baseline values of average peak velocity at rest were 24.6 +/- 11.5 cm/s for ITA-LAD conduits and 21.9 +/- 6.8 cm/s for ITA-CX pedicles. Following dilative stimulation with papaverine, a significant increase in average peak velocities were obtained for both locations (ITA-LAD: 47.3 +/- 17.1 cm/s, ITA-CX: 42.3 +/- 11.8 cm/s). The application of nitroglycerin had a similar effect (ITA-LAD: 42.6 +/- 15.3 cm/s, ITA-CX: 40.3 +/- 10.7 cm/s). The vascular diameters of ITA conduits remained unchanged on nitroglycerin stimulation, whereas papaverine effected significant dilatation in both locations. Flow rates at rest were not significantly different (ITA-LAD: 51.0 +/- 34.2 ml/min, ITA-CX: 44.7 +/- 16.4 ml/min) and maximal flow increase was observed following papaverine stimulation of the LAD conduits (116.1 +/- 90.6 ml/min). Dilative stimulation effected an increase in diastolic-systolic velocity ratios from average values at rest in a range between 34% and 41.7% for both groups and substances. CONCLUSIONS: The basic blood flow in functioning ITA grafts appears to be similar in conduits supplying the LAD and marginal branches. Flow rates between 50 and 60 ml/min at rest should meet myocardial demands, even in the LAD position. Increased flow rates were predominantly based on higher flow velocities with an increased diastolic flow proportion. Enlargement of the graft diameter may exert additional effects, at least following papaverine stimulation at a particular concentration.

Blood Flow Velocity↗
PubMed1996

Do long-term results justify bridging to heart transplantation in patients with multi-organ dysfunction?

This retrospective study was performed to determine the influence of multi-organ dysfunction and the type of preoperative hemodynamic support on mortality after heart transplantation. All patients undergoing heart transplantation during a 6 year period were divided into 3 groups: group A patients (n = 110) had stable hemodynamics on oral medication, group B recipients (n = 41) received continuous i.v. catecholamine application, and in group C (n = 21) mechanical hemodynamic support was necessary. In groups B and C elevated serum creatinine and transaminase levels-reflecting renal and hepatic dysfunction-were detected more often and the survival rate was worse during the first six months (A: 85%, B: 71%, C: 52%, p < 0.01). In group C the prognosis of patients with multi-organ dysfunction was significantly worse compared to patients with normal renal and hepatic function (38% vs. 75%; p < 0.01). In recipients surviving for six months, there was no difference in long-term prognosis between the groups studied. It is concluded that heart transplantation in patients with multi-organ dysfunction on invasive hemodynamic support bears a significantly increased risk in the early postoperative period. In view of the current donor shortage the condition of other organs should be improved before transplantation as far as possible, even using long-term mechanical support.

Adult↗
PubMed1996

[Coronary heart disease and impaired left ventricular function in patients over 80 years of age--is bypass operation justified?].

Between April 1988 and February 1995, 35 patients aged 80 years or older underwent elective coronary artery bypass grafting. Concomitant aortic valve replacement was performed in eight patients. Fifteen patients with moderate to severe left ventricular dysfunction (left ventricular ejection fraction (EF) 20 to 45%) (group I) were compared to 20 patients with an EF > 45% (group II). There were no differences according to age, NYHA classification and associated diseases. Group I patients had significantly more myocardial infarctions compared to group II (1.3 +/- 1.1 vs. 0.5 +/- 0.8; p < 0.05). Also more bypass grafts per patient were used in group I (3.1 +/- 0.9 vs. 2.3 +/- 0.9; p < 0.01). No differences between the groups were observed in the postoperative course. One patient of group II died from multiorgan failure (hospital mortality 2.2%). A follow-up could be performed in 32 of 34 hospital survivors (94%) 12.0 +/- 11.2 months (1-41 months) postoperatively. There was one non-cardiac death in each group. All hospital survivors improved by at least one NYHA functional class. Actuarial survival at 3 years is 91% in both groups. In patients aged 80 years or older with or without left ventricular dysfunction coronary artery bypass surgery can be performed with an acceptable risk and a functional benefit. Thus, elective operations should be performed in this age group despite left ventricular dysfunction.

Aged↗