F W Hehrlein’s research while affiliated with University of Giessen and other places

Therapy for the hypoplastic left heart syndrome (HLHS) is still under debate. We report about our experience in the treatment of this cardiac malformation using heart transplantation and Norwood palliation. From 1988 to 1997 a total number of 30 infants with hypoplastic left heart underwent heart transplantation. Mean age at transplantation was 66 days. Mean waiting time was 53 days. Donor-recipient weight ratio ranged from 0.6 to 3.9. There were 6 early hospital deaths and one late death until now. Causes of death were rejection (3), right heart failure (2), infection (1) and multi system organ failure (1). Overall survival was 77%. Increasing experience improved results substantially. From 1988 to 1993 (n=12) survival rate was 58%, whereas from 1994 to 1997 (n=18) survival rate increased to 88%. Quality of life is excellent in the 23 surviving infants. Only one infant shows severe morbidity (neurological defect). The Norwood procedure has been performed in 18 patients since 1993. Five patients died after the first stage. Up until now 10 infants have undergone the second stage and one infant the third stage procedure. None of them have died. Survival rate is 72% for the whole group. Taking into account that 12 infants died on the waiting list for transplanatation (28%), we have comparable results in terms of the survival rate for transplantation and the Norwood procedure in infants with HLHS since 1994. However quality of life and physical development are far better in infants after transplantation according to our experience. Therefore we prefer, whenever possible heart transplantation in the treatment of hypoplastic left heart syndrome. Certainly not all infants with this malformation can undergo transplantation because of the lack of donor organs. Criteria for the decision regarding the operative strategy in our opinion are function of the right ventricle and tricuspid valve, size of the interaterial communication and parental request.

Maintaining an adequate cerebral oxygen supply is a serious problem in aortic arch surgery. Deep hypothermic circulatory arrest is the most common method used for cerebral protection, but guarantees only a time-limited safety period. Based on experimental investigations, we applied selective cerebral perfusion via the innominate artery alone with only moderate hypothermia (28 degrees C) and without circulatory arrest in 25 consecutive patients undergoing surgical treatment of an aneurysm (n = 10) or acute type-A dissection (n = 15) involving the aortic valve and arch. In every case a test perfusion was carried out to assess whether the cerebral perfusion achieved would be adequate for the whole operation. In no case was the perfusion inadequate. As a new perioperative monitoring system, we used computer-aided topographical electroencephalometry (CATEEM). There were 18 male and 7 female patients, their age was 47.0 +/- 15.1 years (mean +/- SD). Mean time periods were 155.1 +/- 37.3 min for aortic cross-clamping, and 69.3 +/- 35 min for selective cerebral perfusion. Postoperatively, two patients (8%) revealed a temporary left-sided hemiparesis, and 4 patients (16%) died within 30 days. The overall mortality rate was 16% in a follow-up period of 24.2 +/- 9.5 months. In this small group the CATEEM monitoring enabled an intraoperative selection of patients with sufficient bihemispheric collateral circulation and therefore suitable for simple innominate artery perfusion.

Currently the most used perfusion techniques during aortic arch surgery to prevent cerebral damage include hypothermic circulatory arrest, retrograde cerebral perfusion and selective cerebral perfusion (SCP). The application of simplified SCP, which does not require deep hypothermia, has become an alternative procedure for brain protection. Including the physiological principle of autoregulated cerebral blood flow, cerebral perfusion flow is not predetermined, but differentiated from the different cannula sizes for the lower and upper body perfusion. In a mock circulation loop, we could show that resistance changes in the two compartments led to flow shifts between the systemic and brachiocephalic regions. In addition to mechanical factors, cerebral perfusion is determined from physiological changes. In practice, these shifts can be initiated with disrupted autoregulation due to ph-stat management or dramatic pressure changes. To prevent mismatched cerebral perfusion extended perioperative monitoring was included in our clinical setting. With bilateral somatosensory evoked potentials, a computer-aided topographical electroencephalometry system, transcranial doppler-sonography and jugular venous bulb saturation, we could provide a sufficient bihemispheric perfusion. Between 1990 and 1995 we operated on 21 patients using SCP. Intraoperatively no signs of cerebral ischaemia due to inadequate perfusion could be observed. Only temporary neurological changes were found postoperatively. In summary, the simplified SCP, despite its physiological basis, is intricately involved in control and influence. We think that the application of SCP is safe if extended neurophysiological monitoring is included in the clinical setting.

The introduction of fixed reimbursement rates in Germany for cardiac surgery of adults, mainly coronary artery bypass grafting (CABG) and valve surgery, has shifted the financial risk from insurers to providers of medical care, namely hospitals. Costs in turn are closely related to the preoperative condition of a patient, implicating that surgery in high-risk patients may result in financial losses for the operating institution. Furthermore, reports from the Society of Thoracic Surgeons national database indicate a trend over time towards a higher proportion of patients with adverse risk factors for the United States. To determine whether these trends are holding true for Germany, we conducted an analysis of the data from two institutions with the following questions: 1. Is there a trend over time towards unfavourable risk factors, and 2. Is there a relation between preoperative risk factors and postoperative length of stay? From 1987 to 1995, 3872 patients underwent CABG at the Departments of Cardiovascular Surgery of Justus-Liebig University Giessen and German Heart Center Munich. Medical history, preoperative condition, intra-, and postoperative course were recorded for these patients according to the protocol of the German quality assurance program. Preoperative condition of the patient was summarized with an additive risk score. The correlation between postoperative length of stay in the intensive care unit (ICU) and preoperative risk was investigated. For a subgroup of 30 patients, detailed cost analysis was performed and the relationship to preoperative risk examined. For all risk factors examined, a significant increase in prevalence between 1987 and 1995 was observed. A close correlation between preoperative risk and postoperative length of stay in the ICU was found. A similar correlation existed between preoperative risk and actual costs of treatment. In addition, high-risk patients had a significantly higher likelihood of being discharged directly from our ICU to the ICU of other hospitals. Postoperatively, high-risk patients suffer more often from morbidity with subsequent prolonged intensive care and are, therefore, a financial burden for the operating institution in a reimbursement system with fixed rates. This is aggravated by the fact that a trend towards adverse risk profiles among patients undergoing cardiac surgery can be observed. Both factors combined may result in a scenario where those who would benefit most are denied surgical treatment.

Patients undergoing cardiovascular surgery are known to develop a 'postperfusion-syndrome' which often results in severe organ dys functions. This phenomenon is caused by exposure of blood to the surfaces of cardiopulmonary bypass (CPB). The aim of our study was to investigate the fluctuations in cytokine production during and after CPB. In 20 patients undergoing coronary artery bypass grafting, plasma levels of interleukin-2 (IL-2), interleukin-6 (IL-6), neopterin and soluble interleukin-2 receptor (sIL-2R) were measured at eight time points before, during, and after CPB using a standardized ELISA-technique. IL-2 levels decreased after onset of CPB until 24 hours postoperatively (p < 0.05). The production of IL-6 was increased, reaching a peak value six hours after CPB (p < 0.05). Increased neopterin levels were detectable shortly after the onset of CPB (p < 0.05). Serum levels of sIL-2R were significantly decreased after CPB but reached elevated values postoperatively. The results of our study indicate that an intraoperative immunosuppression is followed by an early-postoperative systemic immunological activation.