Search PubMed⌕ Search

Biomedical subjects

R Hetzer

Publications and source records attributed to R Hetzer.

At least 271 records · Page 15Linked to original sources

The use of biocompound-grafts together with varicose veins. First clinical experience.

Complete revascularisation of patients with multivessel disease and inadequate veins is unsatisfactory despite the more frequent use of different arterial conduits. The lack of an accurate vascular prosthesis in coronary artery surgery forces to use in a certain number of patients varicose or ectatic veins. In these cases, an ultraflexible metal mesh tube is placed intraoperatively with the aid of an application set outside the harvested vein and the two joined with fibrin glue (=biocompound-graft). It reduces the graft diameter and improves the hemodynamic properties of the graft. In 18 patients with no alternative graft, 43 biocompound-bypasses were implanted. The total number of implanted bypasses is 58 (mean 3.2+/-1.0). At hospital dismission 41 of 43 biocompound-bypasses are open. One patient died 2 months after the operation. At follow-up (3.9+/-4.0 months), 16 patients are at NYHA stage I or II, one patient at stage III. The first angiographic control in one patient shows all bypasses patent. First analysis of the results encourages continuous use of the biocompound-graft. The biocompound-graft offers the surgeon the possibility of using varicose-ectatic veins if alternative bypasses are not available. Moreover, there is experimental evidence of reduced intimal hyperplasia when mechanical unloading of the vein-wall tension is performed.

Aged↗

Electric myocardial impedance registration in humoral rejection after heart transplantation.

BACKGROUND: Because of the absent lymphocyte infiltrate, humoral-mediated rejection after heart transplantation is not diagnosed by the usual staining technique (hematoxylin-eosin method) of the endomyocardial biopsy specimen. However, humoral rejection is characterized by a distinct myocardial edema caused by capillary leakage. Because tissue edema increases the electric myocardial impedance of the corresponding tissue compartment the electric myocardial impedance method should be able to detect these episodes more reliably than biopsy. METHODS: To evaluate this hypothesis eight DLA-matched beagle dogs were subjected to heterotopic neck heart transplantation after multiple sensitization by skin grafts of the heart donor. For electric myocardial impedance registrations rectangular impulses (wide 1 msec) were applied over two intramyocardial electrodes and the impulse response was registered. Day-to-day comparisons were made and an increase of electric myocardial impedance of 10% or more was used as an indicator of rejection. To assess the influence of edema caused by electrode implantation, cortisone administration, narcosis, ischemia, or reperfusion on the electric myocardial impedance, identical electrodes were implanted in the native hearts of five additional dogs via lateral thoracotomy. These animals each received 100 mg methylprednisolone between postoperative days 20 and 22 and underwent heterotopic neck heart transplantation on postoperative day 28 without previous sensitization (protocol 2). Electric myocardial impedance electrodes were also implanted in these allografts (protocol 3). After transplantation myocardial biopsies were done every 2 days and the samples graded according to the International Society for Heart and Lung Transplantation classification in all dogs. RESULTS: Despite triple-drug immunosuppression (cyclosporine A, prednisolone, azathioprine) humoral rejection developed in all sensitized dogs as established by immunofluorescent staining of myocardial biopsy samples and functional deterioration. All episodes were diagnosed by electric myocardial impedance (sensitivity 100%), whereas only in one case the biopsy specimen was positive (International Society for Heart and Lung Transplantation grade > 1) (sensitivity 12.5%). All eight episodes could be treated successfully, that is, myocardial performance and electric myocardial impedance showed an immediate and full recovery. During the first 12 days none of the nonsensitized dogs exhibited rejection. Protocol 2 indicated that narcosis and the administration of cortisone did not per se have an influence on electric myocardial impedance and the influence of electrode implantation was negligible. Contrarily, edema caused by ischemia and reperfusion during transplantation (protocols 1 and 3) led to a significant increase in electric myocardial impedance. However, after 2 days this edema had faded away such that it no longer disturbed rejection diagnosis. CONCLUSION: We conclude that the registration of the electric myocardial impedance diagnoses humoral rejection episodes after heart transplantation not only reliably but also early, that is, before the onset of irreversible graft damage.

Animals↗

Correction of complete atrioventricular septal defects with the double-patch technique and cleft closure.

BACKGROUND: Controversy continues to surround determining which is the most beneficial method of complete atrioventricular septal defect repair, eg, one- versus two-patch repair, closure of mitral cleft, and the necessity of annuloplasty. METHODS: Between January 1988 and November 1995, 120 patients with complete atrioventricular septal defect underwent total correction at the German Heart Institute Berlin. Sixty-nine of the patients were infants and 51 were children or adolescents. Eleven patients had previously undergone pulmonary artery banding. One hundred three patients had Down's syndrome. In all 120 patients complete atrioventricular septal defect repair was performed using the two-patch technique. The mitral cleft was closed with interrupted sutures in 119 cases. RESULTS: Thirty-four patients required aggressive treatment of postoperative pulmonary hypertensive crises (including nitric oxide inhalation). There were 12 hospital deaths (10%). Mortality was highest in patients with persistently high postoperative pulmonary arterial pressure (pulmonary artery pressure/systemic artery pressure > 0.6) (7 of 17 patients died; 41%). Associated atrioventricular valve anomalies, especially dysplastic valve tissue and severe preoperative cardiopulmonary instability necessitating catecholamine support and artificial ventilation, represented other risk factors. There were six late deaths (5%); cumulative mortality was 15%. Four patients suffered a complete heart block and sick sinus node syndrome necessitating pacemaker implantation 1 to 6 months after operation. During the follow-up period (3 to 80 months after operation), 7 patients (6.8% of survivors) were successfully reoperated on after significant mitral valve incompetence due to an open "cleft" (suture failure) developed. CONCLUSIONS: Correcting complete atrioventricular septal defect using the two-patch technique, routine cleft closure, and atrial septal incision led to a low incidence of residual mitral valve incompetence. Mortality was primarily influenced by severe cardiopulmonary instability and additional atrioventricular valve anomalies preoperatively and the persistence of high pulmonary arterial hypertension postoperatively.

Administration, Inhalation↗

Characteristics of patients younger than 40 years of age operated for coronary artery disease.

This study reviews data on 126 patients (107 men, 19 women) younger than 40 years of age who underwent coronary artery bypass grafting during an 8-year period. They were matched to a control group which also consisted of 126 operated patients but exceeding the age of 39. The majority of the patients in the study group presented with angina; 85.9% were CCS III or IV compared to 61.9% in the control group. More than 3 fourths of the patients (80.5%) had experienced at least 1 myocardial infarction. There was a high incidence of coronary risk factors, especially hyperlipoproteinemia (88.5%), smoking (85.1%), and hypertension (83.1%), whereas in the control group these risk factors occurred in only 49.2%, 21.4%, and 53.2% of the patients, respectively. Other risk factors like diabetes mellitus or family history of coronary artery disease were found in 10.3% and 48.6% of the young patients. While 23.0% of the patients had varying degrees of left main stenosis, 9.5%, 18.3%, and 72.2% had single, double, and triple vessel disease, respectively. Left ventriculograms showed serious functional impairment (ejection fraction less than 40%) in 22.2% of the patients. A total of 286 saphenous vein grafts (2.3 grafts per patient) and 126 internal mammarian grafts were implanted, whereby an internal mammarian graft was always used. In 6 patients we used an intermittent mechanical support system (intraaortic balloon pump in 5 patients and an assist device in 1). In-hospital mortality rate was 1.6% (2 patients); long-term mortality rate 5.2% (mean follow-up interval 54 +/- 20 months). Actuarial survival was 93.0%, 89.8%, and 89.8% at 3,5, and 7 years, respectively. Survival in patients with normal and impaired ejection fraction was significantly different (p < 0.035) for 5-year and 7-year survival (100% vs. 81.8%). We observed encouraging intermediate term results in young adult patients after coronary revascularization. This may have been due to the consistent use of internal mammary artery grafts.

Actuarial Analysis↗

Extracorporeal membrane oxygenation as a bridge to cardiac transplantation in children.

The feasibility and efficacy of extracorporeal membrane oxygenation (ECMO) as a bridge to cardiac transplantation was examined in 6 pediatric patients who suffered irreversible myocardial failure after undergoing surgery for congenital heart defects. The mean time of ECMO support was 260.5 h, range 101-402 h. Three patients underwent transplantation, 2 of whom are long-term survivors. Progressive hypotension as a result of capillary leak syndrome precluded further ECMO support in the other 3 patients. Overall, 2 of the 6 patients survived. Major complications were encountered in 4 patients including bleeding in 2, a seizure in 1, and renal failure in 3, 2 of whom recovered renal function after transplantation. Infection did not occur in any of the 6 patients. Exchanging ECMO components was performed with no difficulties; these exchanges included a centrifugal pump once for 3 patients and a membrane oxygenator once for 2 patients. Our results indicate that ECMO can safely keep critically ill pediatric transplant candidates alive for more than 1 week with a low incidence of multiple organ failure.

Adolescent↗

Mycotic aortic aneurysms after orthotopic heart transplantation: a three-case report and review of the literature.

Mycotic aortic aneurysm is a rare yet life-threatening complication after orthotopic heart transplantation. This article reviews three cases of mycotic aortic aneurysm in heart transplant recipients developing in the first year after heart transplantation. Excision of the aneurysm and in situ reconstruction of the ascending aorta were performed with a patch of glutaraldehyde-fixed pericardium or cryopreserved aortic allograft material as a patch or conduit replacement. These cases show that early diagnosis by computed tomographic scanning, surgical treatment, high-dose parenteral antibiotics, and close follow-up are essential for successful treatment.

Adult↗

Freehand subcoronary aortic valve and aortic root replacement with cryopreserved homografts: intermediate term results.

BACKGROUND AND AIMS OF THE STUDY: The traditional method of aortic valve replacement with a homograft has been free-hand insertion in the subcoronary position. Recently, total root replacement has become increasingly popular. We present our experiences with both methods in this study. MATERIAL AND METHODS: Between January 1, 1987 and March 31, 1996, 208 patients underwent homograft replacement of the aortic valve (free-hand subcoronary technique, n = 147 and root replacement, n = 61). The age of the patients ranged between 1.5 and 78 years with a mean age of 41 years. There were 55 females and 153 males. Ninety-four patients had infected aortic root (with 47 ring abscesses) and 114 patients had sterile aortic roots. In these series, patients with small aortic root, complicated endocarditis, dilated aortic annulus and aneurysm received aortic root replacement. RESULTS: The hospital mortality of patients with non-infected and infected roots was 2.6% and 8.5% respectively making an overall hospital mortality of 5.2%. In patients with free-hand subcoronary valve implantation (AVR) and root replacement (ARR) techniques the hospital mortality was 3.4% and 9.8% respectively. The major risk factor for death was New York Heart Association functional class IV with sepsis. Eight years patient survival in patients with AVR and ARR was 95% +/- 2% and 86% +/- 4% respectively. Freedom from structural deterioration in patients with AVR and ARR was 96.5% +/- 2% and 98% +/- 3% whereas freedom from reoperation was identical 94% +/- 2% and 93% +/- 4% respectively. However, the incidence of reoperation in patients under 40 years of age, particularly in children (< 16 years of age) during the eight years' follow up was 27%. The rate of recurrent endocarditis was 3.6% in ARR patients and development of postoperative pseudoaneurysm formation occurred in 1.4% of AVR patients with endocarditis. CONCLUSION: In conclusion, ARR technique provides low rate of reoperation in the early postoperative period. Cryopreserved homografts in the subcoronary position in adult patients < 40 years of age showed excellent medium term durability and hemodynamic performance providing evidence that long term outcome with a meticulous subcoronary implantation technique is comparable to that with the ARR technique.

Adolescent↗

Blood contact with artificial surfaces during BVAD support.

Persistently elevated levels of cytokines (IL-6, IL-8) during the course of mechanical circulatory support correlated well with fatal outcome. To determine the influence of blood/artificial surface interaction on the chronic inflammatory process, we studied the biocompatibility of silicone and polyurethane membranes in vitro. Cultures of isolated mononuclear cells or whole blood were incubated for 24 hours in tubes coated with silicone or polyurethane, both used in the construction of ventricular assist systems. Concentrations of several inflammatory mediators were measured in the supernatant. Our results can be summarized as follows: a) Monocytes were stimulated to release inflammatory cytokines like IL-8 and MIP-1 alpha, particularly when silicone was involved; b) Both silicone and polyurethane stimulated thrombocytes thus resulting in the release of P-Selectin and PDGF-AB, although polyurethane was a stronger stimulus; c) Moderate complement activation was triggered by contact with either of the artificial surfaces. However, the prevention of most of these effects by coating the artificial surface with protein and the lack of correlation between in vitro data and serum levels of IL-6 and IL-8 during the course of circulatory support suggest that the persistence of inflammatory cytokines during BVAD support is not caused by blood/surface interaction.

Adolescent↗

Blood flow in the internal mammary artery after the administration of papaverine during coronary artery bypass grafting.

Between January 1993 and February 1994, 106 patients whose internal mammary arteries were to be used for revascularization to treat coronary artery disease were examined for a prospective study of papaverine administration. The mean blood flow in the internal mammary artery was 59.9 mL/min +/- 7.3 mL/min before papaverine administration. The patients were divided into 3 groups: in Group I papaverine was administered intraluminally, retrograde in the internal mammary artery; in Group II, it was administered topically; and in Group III, it was administered perivascularly, in the pedicle. After papaverine administration, the mean blood flow in Group I was 135.7 mL/min +/- 10.1 mL/min; in Group II, it was 84.8 mL/min +/- 8.3 mL/min; and in Group III, it was 136.3 mL/min +/- 9.7 mL/min. The highest increases in blood flow were observed in Group I (105.3%) and in Group III (112.6%). On the basis of our results, we recommend that papaverine be injected perivascularly into the pedicle of the internal mammary artery, since retrograde injection can cause dissection.

Adult↗

[Adults with congenital heart defects--clinical spectrum and surgical management].

Two hundred adults who underwent surgery for congenital heart disease at our institution within a four year period were the basis for this report. Clinical data was obtained, i.e. demographic details, past medical history, physical findings, EKGs, echocardiograms, catheterization and angiography material as well as the New York Heart Association (NYHA) class. Intraoperative findings, perioperative management, complications and morbidity and mortality were assessed. After discharge the patients were followed on an outpatient basis. Again the clinical findings, laboratory results and NYHA class were recorded. Age ranged from 16 to 75 years (mean = 38). There were 114 females and 86 males. 178 patients had primary surgical correction, 18 were reoperated after prior correction and 4 underwent palliation. Eighty-three percent of the patients were symptomatic preoperatively. Seventeen percent were diagnosed per chance, for example by a preemployment physical examination, without a prior history of heart disease. The patients were grouped according to related diagnoses (Table 1). Among the 130 patients with left to right shunts, 112 had an atrial septal defect, 7 a ventricular septal defect, 5 a persistent ductus arteriosus, and 6 partial anomalous pulmonary venous return. Atrial flutter or fibrillation occurred in approximately 10% of all patients with atrial septal defects. It was terminated either by rapid overdrive pacing or DC cardioversion. Postoperatively the patients with pulmonary hypertension were monitored invasively with arterial lines and thermodilution catheters. Therapy consisted of alkalization, hyperventilation and sedation. There was only one postoperative death in this patient group due to marked pulmonary hypertension (1/130 = 0.8%). Nineteen adults had obstruction to right or left ventricular outflow. Surgery included valvotomy, infundibulectomy and valve replacement by homograft or mechanical valve. One patient with multiple previous surgeries expired due to bleeding (3%). Thirteen patients had coarctation. All of them were hypertensive, some on medication. Surgery consisted of aortic patchplasty or interposition of a graft. There was no mortality. Perioperative antihypertensive therapy was necessary in most patients and consisted of nifedipin, nitroprussid or propanolol intravenously. Upon follow up 11 patients became normotensive, 8 of these without the need for medication. Fifteen cyanotic patients underwent 11 corrective and 4 shunt procedures (3 with tricuspid atresia, 10 with Tetralogy of Fallot and 2 with complex cyanotic heart disease. Three died due to low cardiac output or dysrhythmias (20%). The survivors improved their clinical status markedly. Seven adults with Ebstein's disease had valve reconstruction and/or ASD closure. Five had recurrent supraventricular tachycardia, 2 paradoxical emboli with neurological symptoms and 4 out of 7 had decreased exercise tolerance. One patient died postoperatively because of dysrhythmias (14%). Sixteen patients had a variety of defects, i.e. status post Rastelli operation and conduit obstruction, status post Tetralogy of Fallot with pulmonary valvar disease, corrected transposition with left AV valve insufficiency, congenital mitral valve disease and double aortic arch, no deaths. The overall operative mortality was 6/200 = 3%. the late mortality was 4/200 = 2%. The morbidity included 7 reoperations due to bleeding. Five patients needed short-term hemodialysis. One patient developed hemiplegia and two patients had permanent decrease of their left ventricular function. The mean length of follow up was 21 months. The clinical status improved from a NYHA class mean of 2.1 +/- 0.9 to 1.2 +/- 0.45 (p < 0.001). In Germany significant numbers of adults with operated and unoperated congenital heart disease do exist. Detection of these patients can be difficult due to inconspicuous murmurs or stable clinical status.

Adolescent↗

[Intramyocardial electrocardiogram (IMEG) in diagnosis of humoral rejection after heart transplantation].

Measuring intramyocardial ECG amplitude is a clinical non-invasive procedure used for diagnosing rejection after heart transplantation. In recent years, as the importance of humoral mediated rejection has increasingly been recognized, the fact that endomyocardial biopsies often produce false negative results due to the absence of lymphocytic infiltrates has become a matter of concern. In order to test the reliability of IMEG diagnosis of this form of rejection, heterotopic neck-heart transplantation was performed on eight beagles which were previously sensitized through several skin transplantations. Over the course of the study IMEG registrations were performed daily as well as echocardiographic examinations to determine left ventricular wall thickness and maximal diastolic relaxation velocity. Donor-specific antibodies in serum (IgG, IgM) were also determined daily. Myocardial biopsies, performed once every 2 days, were examined for the presence of edema and lymphocytic infiltrate (according to the guidelines of the International Society of Heart and Lung Transplantation, ISHLT) and examined under immunofluorescent microscopy of IgG and IgM. Under triple drug immunosuppression with cyclosporine A, azathioprine, and cortisone accelerated rejection occurred on the fifth postoperative day (range: 4th-5th). All eight episodes were detected through IMEG diagnosis (sensitivity 100%), while the myocardial biopsies graded according to ISHLT guidelines indicated only one case of relevant lymphocytic infiltrate (Grade 3A) (sensitivity 12.5%). In each case rejection was recognized so early that it was possible to perform therapy with restitutio ad integrum. This proved that, as opposed to endomyocardial biopsy, IMEG diagnosis detected humoral mediated rejection early and with high reliability. Furthermore, the immediate recovery in IMEG during therapy indicates that the voltage decrease cause by rejection cannot be explained by an irreversible loss of myocardium (myocytolysis), but rather may be due to a quickly reversible functional impairment.

Animals↗

[Inflammatory mediators in patients with biventricular assist device systems].

We studied the plasma levels of TNF-alpha, IL-6, IL-8 and soluble adhesion molecules (sE-Selectin, sL-Selectin, sVCAM-1) immediately before and during mechanical circulatory support with a Biventricular Assist Device System (BVAD-"Berlin Heart") in comparison to patients with chronic heart failure (NYHA classes II/III) and patients with coronary artery disease with normal ventricular function. Additionally, the biocompatibility of the membranes used in the "Berlin Heart" was tested in vitro. IL-6 and IL-8 but not TNF-alpha could only be detected in patients with cardiogenic shock immediately before starting circulatory support. Furthermore, plasma concentrations of soluble adhesion molecules were statistically significantly elevated in patients with cardiogenic shock compared to patients with coronary artery disease. This picture of a systemic inflammatory response syndrome without significant level of TNF-alpha looks quite similar to that seen in patients following trauma and severe operations. During mechanical circulatory support plasma levels of cytokines and soluble adhesion molecules dropped to low levels in patients, who were successfully maintained on BVAD. By contrast, we have found persistently elevated levels of these mediators in patients with fatal outcome. This seems not to be the result of individual distinct response of blood cells to contact with the artificial surfaces of the device. In summary, our data suggest the development of a systemic inflammatory response syndrome may be due to hypoxia during cardiogenic shock. Persistence of systemic inflammation suggests failing of the mechanical support. Therefore, the monitoring of inflammatory mediators may be relevant as a prognostic marker in these patients (disappearance of peripheral hypoxia).

Adult↗

[Evaluating physical fitness after unilateral lung transplantation with ergometry and blood gas analysis].

7 patients aged 30-56 years with the perception of subjective increased fitness 4-22 months after single lung transplantation were tested for the objective benefit. Using a standardized ergometric test protocol cardiopulmonary parameters (ventilation, blood gases, gas exchange, blood pressure, ECG) were measured 5 males and 2 females. After transplantation in all patients the objective fitness was increased by 30-60 watts and the blood gases were markedly improved. The physical fitness of the subjects under study was probably limited by the reduced lung function of the native lung, the reduced mobility of the diaphragm in elderly patients and the impaired muscular strength and endurance.

Adult↗

Regulation, chamber localization, and subtype distribution of angiotensin II receptors in human hearts.

BACKGROUND: To assess the chamber localization, subtype distribution, and regulation of human myocardial angiotensin II receptors in heart failure, we determined the binding of angiotensin II, Sar1Ile8-angiotensin II, and the subtype-specific antagonists Dup 753 (AT1-specific) and PD 123319 (AT2-specific) in atria from patients with normal (left ventricular ejection fraction > 55%) or moderately impaired (left ventricular ejection fraction 30% to 55%) cardiac function and in atria and ventricles from explanted end-stage failing hearts. Sarcolemmal and combined fractions, the latter including internalized receptors, were studied. In addition, AT1 mRNA content was analyzed by polymerase chain reaction after reverse transcription. METHODS AND RESULTS: The number of angiotensin II binding sites (Bmax) in sarcolemmal fractions was significantly reduced in explanted end-stage failing hearts in comparison with control subjects and moderate heart failure (Bmax 3.9 +/- 0.8 versus 11.2 +/- 1.7 and 9.6 +/- 0.8 fmol/mg protein, respectively). A comparable 65% reduction in receptor numbers was found in combined fractions from end-stage failing hearts, indicating that the loss of binding sites was not due to their internalization. The dissociation constants were comparable in sarcolemmal and combined fractions and in nonfailing and failing hearts, ranging from 0.5 +/- 0.2 to 1.2 +/- 0.5 nmol/L. In nonfailing hearts, 69 +/- 4% of binding sites were blocked by the subtype-2-specific inhibitor PD 123319 and were therefore classified as AT2; 33 +/- 5% were blocked by the subtype-1-specific inhibitor DUP 753 and thus classified as subtype 1. In explanted hearts, comparable ratios of 66 +/- 5% AT2 sites and 34 +/- 5% AT1 sites were found. AT1 cDNA amplification signals by polymerase chain reaction were reduced to about one third of the level in control subjects in end-stage failing hearts. CONCLUSIONS: Angiotensin II receptors in human myocardium are present in relatively low numbers, and AT2 is the predominant subtype. A significant loss of angiotensin II receptors occurs in end stage but not in moderate heart failure. The loss of receptors affects both subtypes to a comparable degree. The data suggest that the decrease in receptor density is due to a decrease in steady-state mRNA abundance.

Binding Sites↗

[Urodilatin. Use of a new peptide in intensive care].

On the subject of natriuretic peptides there is a great deal of controversy, and intensive research efforts have been made studying their effects on electrolyte homeostasis. In the early 1980s, a peptide that caused diuresis, natriuresis, and had a relaxant effect on vascular smooth muscle was discovered independently by several groups. This was the breakthrough for the identification of natriuretic peptides, followed by the characterisation of the amino-acid sequences of several species. Synthesis of the peptide, cloning of the encoding gene, identification and characterisation of specific receptors, as well as the development of antibodies and radioimmuno-assays were rapidly accomplished. Research on the immunohistochemistry of cardiodilatin/atrial natriuretic peptide (CDD/ANP) and the regulation of CDD/ANP gene expression led to detection of the peptide in extra-atrial tissues. Later on, two new peptides were discovered brain natriuretic peptide (BNP) and C-type natriuretic peptide (CNP). These peptides share structural features with CDD/ANP with regard to their 17-amino-acid-exhibiting loop bridged by a disulfide bond. Another recently discovered peptide is urodilatin (URO), a renal-borne new member of A-type natriuretic peptide. URO was isolated from human urine and consists of the same sequence as CDD/ANP, containing the 17-amino-acid residue loop of the circulating hormone with 4 additional amino acids located at the NH2-terminus of the peptide. Regarding physiological actions, data strongly support a close association between URO and urinary sodium excretion. The application of URO in animals revealed a stronger diuresis and natriuresis with a lower influence on arterial blood pressure compared to CDD/ANP-99-126. These results were encouraging for the use of URO in clinical trials as a tool to prevent acute renal failure (ARF) in patients following heart transplantation and for treatment of incipient ARF in patients following liver transplantation. Summarising the results of these two studies, URO represents a new approach for not only prevention, but also for treatment of ARF following organ transplantation. This opens up new possibilities for the treatment of ARF of other origins in intensive care medicine.

Acute Kidney Injury↗

Prolonged open sternotomy after pediatric open heart operation: experience with 113 patients.

Between April 1990 and November 1993, 1,252 open heart operations were performed in infants and children with congenital heart defects. Prolonged open sternotomy was used in 113 patients (9%) in 10 surgical categories. Thirty-six of these children (32%) were infants and 43 (38%) were newborns. Twenty-four patients (21%) had undergone operation previously; 3 newborns had been treated with extracorporeal membrane oxygenation before the operation. The patients were grouped according to indications for prolonged open sternotomy as follows: group I, 31 patients with squeezed (large) heart syndrome (1 death); group II, 14 patients with hemodynamic instability after sternal approximation (2 deaths/14.2%); group III, 35 patients with low output state after bypass (17 deaths/48.5%); group IV, 21 patients with extracorporeal circulatory assist devices (15 deaths/71.4%); group V, 3 patients with severe arrhythmias (no deaths); and group VI, 9 patients with atypical tamponade that necessitated reopening the sternum in the intensive care unit (6 deaths/66.6%). Overall mortality was 36.2% (41 patients). Four group IV patients were weaned successfully from extracorporeal membrane oxygenation and heart transplantation was performed successfully on two others. All but one of the deaths occurred before delayed sternal closure. After hemodynamic stabilization was achieved, the sternum was closed in all 72 surviving patients with absorbable sutures (in 86% within the first 6 days after operation). In 50 patients (69% of survivors) pericardial substitution with a polytetrafluoroethylene membrane was performed. One newborn with mediastinal infection after extracorporeal membrane oxygenation was treated successfully with retrosternal drain and suction lavage.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Accelerated degeneration of allografts in the first two years of life.

Between January 1988 and May 1994, 53 of 159 patients have received cryopreserved aortic and pulmonary allografts for reconstruction of the pulmonary circuit in the first 2 years of life with body weight ranging from 2.2 to 18 kg (mean, 8.2 +/- 3.4 kg). The implanted allografts ranged in internal diameter from 9 to 23 mm (mean, 16.3 +/- 3.5 mm). Of the 38 survivors who regularly had postoperative echocardiographic examinations 15 (39.5%) underwent cardiac catheterization 1 to 31 months after operation. Allograft dysfunction (gradient > or = 50 mm Hg with or without pulmonary insufficiency) was confirmed in 9 patients leading to reoperation in 5 and valvulo-angioplasty in 4. At 48 months actuarial survival was 64%. In the aortic and pulmonary allografts freedom from wall calcification at 20 months was 19% and 100%, respectively. Freedom from valve dysfunction in patients with aortic and pulmonary allografts was 53% and 88%, respectively; it was 49% in allografts with an internal diameter of 17 mm or smaller. Freedom from reoperation in all patients was 78%. In conclusion, young age, antigenicity (ABO compatibility), and type of allograft seemed to be independent risk factors for early allograft conduit degeneration and late valve dysfunction. Pulmonary allografts seemed to be more resistant to early wall calcification and valve dysfunction than aortic allografts.

Actuarial Analysis↗