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Biomedical subjects

H J Krebber

Publications and source records attributed to H J Krebber.

At least 19 recordsLinked to original sources
PubMed1991

[Results of emergency bypass operation following percutaneous transluminal coronary angioplasty].

Between 1980 and 1988, percutaneous transluminal coronary angioplasty (PTCA) was performed in 1,514 patients. Fifty-five patients (3.6%) underwent emergency coronary bypass surgery because of an acute occlusion of the vessel or a dissection with sustained angina and signs of ischemia on the electrocardiogram. Twenty-five of these 55 patients had a myocardial infarction and 5 patients died, 3 perioperatively, 2 after hospital discharge. The degree of stenosis of the dilated vessel significantly influenced the incidence of infarction, while left ventricular ejection fraction prior to PTCA significantly influenced mortality. Patients who underwent surgery with an occluded vessel experienced myocardial infarction significantly more often (87%) than patients with a patent vessel (24%). The incidence of infarction was 27% when reperfusion of the vessel occluded during PTCA was achieved with a reperfusion catheter, repeated PTCA or intracoronary lysis. The patients' age, presence of unstable angina, left ventricular ejection fraction prior to PTCA, the dilated vessel, the extent of coronary artery disease, collateralization of the dilated vessel, and the time between the onset of the event necessitating bypass surgery and the beginning of extracorporeal circulation were found to have no influence on the incidence of infarction. Patients who died had a significantly lower ejection fraction before PTCA than survivors and all patients who died had experienced a large perioperative myocardial infarction.

Adult↗
PubMed1990

[Central nervous system risk factors in heart surgery].

Serious complications involving the central nervous system in the course of cardiac surgical procedures have become rare. Nevertheless, CNS dysfunctions still are observed in a considerable number of patients, exceeding by far the number of those at risk from preoperative neurological hazards. The influence of extracorporeal circulation performance and hypothermia on the physiology of cerebral autoregulation, as well as microembolization events seem to be crucial factors in this context. The resulting regional or global posthypoxic changes in brain metabolism may lead to the manifestation of various neurologic and psychiatric disorders in the postoperative course. These often minor disturbances of CNS function can only be detected regularly and diagnosed correctly in a prospective way by consulting specialists in neurology, psychiatry and psychology, as performed at the Department of Thoracic- and Cardiovascular Surgery of the University Hospital in Hamburg since 1974, and currently in use an international multicenter study. We found postoperative neurological abnormalities in more than 50% of our patients. While irreversible brain damage occurred in only 0.5% of cases, about twothird exhibited transient symptoms that were no longer apparent after 8-10 days postoperatively. Obvious psychopathological symptoms were noted in 10% of cases after surgery, and minor, likewise transient, psychiatric disturbances were seen in up to 50% of patients; 20% suffered from long-lasting psychic problems. The subjective complaints in these cases exceeded the results of objective assessments to a remarkable amount. The discussion focuses on a critical valuation of clinical and supplementary examination techniques and on the potential pathophysiologic mechanisms induced by extracorporal circulation.

Brain Damage, Chronic↗
PubMed1989

Alcohol-induced coagulation necrosis in cardiac tissue: a new concept in the surgical management of recurrent ventricular arrhythmias.

Post myocardial infarction recurrent ventricular arrhythmias are usually coupled with depressed left ventricular function. We have until recently employed the most widely used surgical techniques such as endocardial resection, cryosurgery and isolation. After these methods had failed in a patient with an extensive septal focus, it finally became possible to effectively ablate the arrhythmogenic area by injection of 10 ml 95% alcohol subendocardially. The following experimental studies were carried out to investigate the effect of direct injection of alcohol on the myocardicytes. 95% alcohol, injected into the apex of the left ventricle of Wistar rats weighing between 150 and 200 g caused extensive coagulation necrosis 5 minutes after injection, as was revealed by histological examination. The site of injection showed marked scar formation after 6 months. On the basis of these findings, 4 more patients were treated successfully with alcohol, which was directly injected subendocardially without endocardial resection using a long needle. The advantage of this procedure is that resection can be avoided, particularly in critical areas such as the septum and regions around papillary muscles.

Animals↗
PubMed1988

Improved survival up to four years after early coronary thrombolysis.

The long-term prognosis after thrombolytic therapy in patients with acute myocardial infarction (AMI) is unknown. This question was investigated in a 4-year follow-up study of 227 patients. According to the status of reperfusion at the end of the acute catheterization, the patients were divided into a patent (n = 171) and an occluded (n = 56) group. Both hospital and 4-year mortality rates were significantly reduced in the patent group by 13 and 14%, respectively (p less than or equal to 0.005 for both). Baseline variables known to be important for prognosis did not differ between the 2 groups. Patients with a patent infarct artery who underwent early acute coronary artery bypass grafting (CABG) had a greater survival (p less than 0.10) and better left ventricular function (p less than 0.01) than did patients with a patent infarct artery who did not undergo CABG. This difference was associated with a lower frequency of fatal reinfarction and cardiogenic shock in the CABG group. Thus, survival is improved up to 4 years after successful thrombolysis and appears to be further enhanced by early CABG.

Cardiac Catheterization↗
PubMed1988

'Head and heart'--neurological and psychological reactions to open heart surgery.

Neurological and psychological reactions to open-heart surgery are widely underestimated phenomena and occur in a much higher incidence than one might expect. When analyzed retrospectively, up to 3.8% of patients who underwent cardiac surgery at the Hamburg University Hospital exhibited these reactions, whereas 35%-50% presented with symptoms and signs of perioperative CNS dysfunctions in prospective studies at our department. About the same percentages are detected in prospective studies of the patients' perioperative psychopathology, stating that a great number of cardiac patients exceed the normal range of anxious, tense, and depressive moods in this setting. The consequences of these findings for the patients' quality of life and the impact for the perioperative management of patients undergoing open-heart surgery are discussed. The current prospective studies, preliminary results of which are presented here, are part of an international interdisciplinary study, initiated to bring more light into the complicated relations between ECC-assisted cardiac surgery, anaesthesiology, neurology and psychology.

Adaptation, Psychological↗
PubMed1985

Bypass surgery following thrombolytic therapy.

The reocclusion rate of infarct vessels following lysis amounted to 61/80 (24%) with a peak during the first week following the acute event. According to Harrison there is a strong correlation between the probability of reocclusion and the diameter of the residual stenosis, while the reocclusion rate is independent from the anti-coagulative regimen. In the presence of preserved myocardial function and significant residual stenoses as well as in patients with multi vessel disease additional PTCA or early bypass surgery seems to be indicated, in order to prevent re-infarction. 55 out of 180 patients following intracoronary lysis, 6 out of 30 following systemic lysis and 2 out of 10 following lysis with TPA were operated upon within one week following the acute event. Hospital mortality was 3.1% (2/63) and late mortality was 1.6% (1/61). Out of 123 bypass grafts 105 (86%) were found to be patent at reangiography. The risk of bleeding was studied in 24 patients who were operated upon within 24 hours following the acute event. Although the clotting factors, especially the serum fibrinogen, had decreased below normal values, there was no increased postoperative blood loss. The coagulation factors had risen to normal values within 24 hours.

Anticoagulants↗
PubMed1984

Intracoronary thallium 201 scintigraphy as an immediate predictor of salvaged myocardium following intracoronary lysis.

Since February of 1980, 157 patients who had had symptoms of acute myocardial infarction for less than 3 hours underwent intracoronary lysis. Forty-six patients required early aorta-coronary revascularization. However, operation was believed to be indicated only when intracoronary lysis was successful and myocardium was salvaged. Since left ventricular angiography proved unreliable in assessing the viability of the myocardium in the acute stage, starting in March of 1981 we obtained intracoronary thallium 201 scintiscans in 23 patients before and after intracoronary lysis. Patients in whom there was a significant reduction (greater than 50%) in the initial 201Th defect (n = 12) were considered ideal candidates for operation (Group 3). Patients with poor or unimproved 201Th uptake after successful intracoronary lysis (n = 6) were treated medically (Group 2), as were patients in whom intracoronary lysis was unsuccessful (n = 5, Group 1). In order to validate this new approach, we compared the change in the regional wall motion of the "infarcted area," as shown in the early and follow-up left ventricular angiograms in all three groups. In the acute stage, the mean regional ejection fraction was 19.9% in Group 1, 19.1% in Group 2, and 20.1% in Group 3. Only in Group 3 was there a significant increase in regional ejection fraction to a mean of 51%. The mean ejection fraction obtained at follow-up in Groups 1 and 2 was 16.5% and 17.3%, respectively. From our findings, we conclude that 201Th scintigraphy is a valuable predictor of the salvageability of myocardium immediately following intracoronary lysis. To date, it has been the most valuable tool in assessing those patients suitable for early coronary revascularization.

Coronary Vessels↗
PubMed1983

[Two-dimensional transesophageal echocardiography: a better presentation of intra-atrial structures].

In seven patients with suspected or detected abnormal intra-atrial structures on 2-dimensional echocardiography, transoesophageal echocardiography was diagnostic of left atrial myxoma in two, left atrial thrombus in two, cor triatriatum in two and right atrial membrane in one. The transoesophageal technique extends diagnostic possibilities. The accurate demonstration of atrial abnormalities in such cases by the transoesophageal technique obviates the need of invasive pre-operative angiographic and haemodynamic procedures.

Adult↗
PubMed1983

Effect of interventions in salvaging left ventricular function in acute myocardial infarction: a study of intracoronary streptokinase.

The ability of intracoronary streptokinase (STK) infused early in acute myocardial infarction (MI) to salvage left ventricular (LV) function was studied in 52 patients who underwent contrast angiography immediately after STK and 6 +/- 7 weeks later. Ten nonrevascularized patients had no lysis or reocclusion. Of 42 patients with thrombolysis, 22 with optimal reperfusion underwent coronary artery bypass grafting (CABG) to prevent rethrombosis (STK + CABG group) and 20 did not (STK group). Motion was measured at 100 chords around the left ventricle and expressed in standard deviations (SD) from the normal mean. Hypokinesia was computed as the mean motion of chords in the infarct artery territory and hyperkinesia on the opposite wall was similarly computed. Hypokinesia improved greater than or equal to 1 SD/chord in 9 STK + CABG patients (41%), 8 STK patients (30%) (p = not significant versus STK + CABG) and 0 nonrevascularized patients. However, the ejection fraction did not change because it was normal in acute MI despite severe hypokinesia due to hyperkinesia on the opposite wall, and a subsequent decrease in hyperkinesia masked significant improvement in hypokinesia. It is concluded that regional wall motion must be measured to adequately assess the effect of therapeutic interventions on LV function. Early thrombolysis in acute MI results in improved LV function. The main benefit of CABG is to prevent rethrombosis.

Adult↗
PubMed1983

[Gas embolisms during operations on the open heart].

During routine open heart procedure the amount of microbubbles released from the oxygenator and the heart into the arterial circulation were measured by ultrasonic probes, placed over the arterial line and the carotid artery. The significance of microbubbles ejected from the cavities of the heart for cerebral cell injury were studied in an experimental model, analyzing enzyme levels in cerebrospinal fluid. A typical phasic bubble-activity was found in both the arterial line and the carotid artery, with an initial high during the initiation of bypass, a lower plateau during perfusion and a slight increase again with rewarming during reperfusion after releasing the aortic cross clamp. The increase of bubble activity during reperfusion was more pronounced in the carotid artery as bubbles released from the heart were added to those coming from the heart lung machine. After leftsided cardiotomy this activity lasted for up to 20 min after termination of extracorporeal circulation (ECC). The use of filters reduced the bubble activity during perfusion significantly, but did not change the activity during reperfusion and after termination of ECC. Liquor enzyme levels were found normal during and after bubbles reperfusion, but rose significantly after leftsided cardiotomy. CO2 wash-out reduced the increase in liquor enzyme levels markedly.

Animals↗
PubMed1983

Transesophageal two-dimensional echocardiography in the diagnosis of cor triatriatum in the adult.

Two adult patients with left ventricular inflow obstruction are presented. Conventional two-dimensional echocardiography had failed to yield a definite diagnosis, whereas transesophageal two-dimensional echocardiography clearly documented a membraneous echo structure within the left atrium, diagnostic of cor triatriatum. On the basis of the transesophageal echocardiographic findings, left heart catheterization and angiocardiography were not performed and both patients successfully underwent cardiac surgery.

Adult↗
PubMed1983

Indication for early aorto-coronary bypass surgery after successful intracoronary lysis.

Intracoronary lysis (ICL) was carried out in 108 patients with acute coronary artery thrombosis. In 79 subjects, recanalization of the occluded vessel was achieved, while 29 patients were unresponsive to the method. Thirty patients required early aorto-coronary bypass (ACB) surgery after successful ICL, while 49 patients with successful lysis were treated medically as well as the 29 patients with unsuccessful lysis. Mortality was 20% among the patients unresponsive to ICL, 12% among the 49 patients with successful lysis treated on a medical regimen thereafter, and 3.3% among the 30 patients undergoing early surgery after successful lysis. Early aorto-coronary surgery, however, was felt to be indicated only when the myocardium supplied by the occluded vessel was still viable. Beside LV angiography and ECG studies, intracoronary Thallium-scintigraphy was most helpful in assessing the viability of the heart muscle.

Coronary Artery Bypass↗
PubMed1983

Detection of ostium secundum atrial septal defects by transoesophageal cross-sectional echocardiography.

Transoesophageal cross-sectional echocardiography has special advantages when investigating the interatrial septum which is imaged perpendicularly without echo dropouts from an oesophageal transducer position. The technique was successfully used in 19 out of 20 patients (95%) with an ostium secundum atrial septal defect and in 30 control subjects. In all of the latter the interatrial septum was visualised as a continuous echo structure separating the atria, whereas a distinct discontinuity representing the septal defect was apparent in all patients with atrial septal defect. Echocardiographic measurement of the defect size correlated well with surgical findings in 11 patients who underwent open heart surgery in the course of this study. In a comparative transthoracic examination, adequate recordings were obtained in 18 of the 20 patients and in 26 of the 30 control subjects. Direct subcostal visualisation of the defect was reliable in 10 of 18 patients. Peripheral venous contrast studies were also performed with the transoesophageal as well as the transthoracic technique. Echo contrast remained confined to the right heart in the control subjects. Left sided contrast appearance diagnostic of an interatrial communication was shown in the patients using the transoesophageal technique (100% sensitivity), with an additional right atrial negative contrast apparent in seven patients. The transthoracic approach, on the other hand, showed left sided echo contrast in 14 of 18 patients and an additional negative contrast effect in two of the 14. It is concluded that transoesophageal is superior to transthoracic cross-sectional echocardiography as a highly sensitive method for the detection and evaluation of ostium secundum atrial septal defects.

Adolescent↗
PubMed1982

Bioadhesives in cardiac and vascular surgery.

Bleeding through the pores of thoracic vascular grafts sealed with bioadhesive has been eliminated without inducing additional defects in the coagulation system. This has been true regardless of whether additional valve replacement or aorto-coronary bypass procedures were performed. The operative risk and the need for blood transfusions has been lowered significantly thus reducing the cost of these procedures. Bioadhesive has been also applied successfully in a variety of perioperative bleeding complications.

Aorta↗
PubMed1982

Acute coronary artery occlusion during percutaneous transluminal coronary angioplasty: reopening by intracoronary streptokinase before emergency coronary artery surgery to prevent myocardial infarction.

Percutaneous transluminal coronary angioplasty (PTCA) was complicated by acute coronary artery occlusion associated with ST elevation and severe chest pain in three patients. Within 10 minutes, the occluded artery was reopened by an intracoronary (i.c.) infusion of streptokinase, resulting in the disappearance of chest pain and normalization of ST segments. To keep the artery patent, i.c. streptokinase had to be continued until emergency bypass surgery was performed. In two patients, no myocardial infarction occurred, as shown by a normal postoperative left ventricular angiogram. ECG and thallium-201 scintigram. In the other patient, who was admitted with an inferior infarction and underwent PTCA after i.c. lysis, no infarct extension was observed. These results show that i.c. streptokinase rapidly opens an acute coronary artery occlusion complicating PTCA, preventing myocardial infarction.

Adult↗