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Biomedical subjects

R Hetzer

Publications and source records attributed to R Hetzer.

At least 379 records · Page 21Linked to original sources
PubMed1986

Noninvasive monitoring of cardiac allograft rejection by intramyocardial electrogram recordings.

Rejection after cardiac transplantation was monitored in nine patients by control of intramyocardial electrogram (IMEG) recordings transmitted by an implanted telemetric pacemaker. Under immunosuppression with cyclosporin A and prednisolone, 33 out of a total of 119 endomyocardial biopsy specimens showed moderate rejection (infiltrate with myocytolysis). Twenty-nine of these rejection episodes could be correctly predicted from IMEG recordings with a voltage drop above 15% used as a criterion (sensitivity 87.9%). Eighty-three of 86 negative biopsy results corresponded to negative IMEG results (specificity 96.5%). In this group of patients, amplitude of body surface electrocardiograms was not useful for the diagnosis of rejection because of the broad range of spontaneous variation. Control of IMEG voltage amplitude appears to be more accurate than body surface electrocardiogram amplitude in the detection of rejection episodes. Thus the onset of rejection during biopsy intervals is more readily detected and treatment is instituted earlier. The method is suitable for ambulatory patient monitoring by the patient's local physician.

Biopsy↗
PubMed1986

[Surgical therapy of intracardiac infected pacemaker electrodes and catheter remnants].

With the increase of pacemaker and central venous catheter implantation the number of intracardiac infections now constitutes a significant problem. Twenty patients between 22 and 77 years of age admitted for intracardial infected pacemaker probes or central venous catheter remnants presented with recurring attacks of endocarditic fever; in one case multiple pulmonary abscesses resulted from septic embolization. Staphylococci were the most frequently involved organism (75%). Risk factors leading to intracardiac infection were local reoperations and diabetes mellitus. Removal of the foreign body was achieved by cardiotomy in all cases. Twelve patients were operated upon without the use of the heart-lung machine, but extracorporeal circulation was necessary in 8 patients. There was one fatality in each of the 2 techniques, for a total mortality rate of 10%. In all cases the foreign bodies were removed without intracardial damage and the endocarditis was cured. When attempts at external extraction fail, the foreign body should be removed by either open or closed cardiotomy. This limits the danger of injury to the heart and of embolization of septic or thrombotic material. The use of the heart-lung machine is especially indicated in the presence of widespread, firm adhesions, or large bacterial vegetations and thrombi.

Abscess↗
PubMed1985

[Heart transplantation in cardiomyopathy].

Within the spectrum of presently accepted candidates for heart transplantation, end-stage heart failure in dilated cardiomyopathy has become the principle indication. Although several indicators of poor prognosis have been specified, the decision for heart transplantation is primarily made on clinical grounds. Expected long-term survival after transplantation is 60 to 80% at one year and more than 50% at five years. Since July, 1983, 50 patients underwent orthotopic heart transplantation, 38 of whom had been suffering from dilated cardiomyopathy. Ages ranged from nine to 54 years with a mean of 40 years. At present, 38 patients are alive, 34 are discharged from hospital, 14 have returned to work or school. Physical capacity and cardiac function are normal. There was no difference between the cardiomyopathy patients and the coronary artery disease patients with respect to rate and severity of rejection episodes, infection and long-term findings. Heart transplantation is considered a promising routine treatment for end-stage heart failure in particular in younger patients with dilated cardiomyopathy.

Adolescent↗
PubMed1985

Heart transplantation--a two-year experience.

In July 1983, a heart transplant program was initiated. Up to September 1985, 72 orthotopic transplants in 69 patients (62 men, 7 women, age 9 to 55 years, mean 40.1 years) have been performed. All patients suffered from end-stage heart failure, which was due to coronary artery disease in 15 patients, congestive cardiomyopathy in 53 patients and endocardial fibrosis in one woman. All patients survived the operation, but there were 6 deaths within the first 30 postoperative days. Eight more patients died subsequently. Causes of death were rejection in 6, infection in 3, cerebral hemorrhage in 2, sudden death in 2 and pulmonary embolism in one patient. Actuarial survival at one and two years was calculated at 75%. The detection of allograft rejection was the major postoperative problem. This was achieved by serial endomyocardial biopsy and myocardial voltage monitoring via a telemetry pacemaker system. The lowest rate of organ toxicity, rejection and infection was achieved using a triple immunosuppressive regime including Azathioprine, Cyclosporine A and steroids with initial doses of antithymocyte globulin. It is concluded that heart transplantation can be regarded as a routine procedure for patients with intractable heart failure. The operative risk is limited, and an elaborate immunosuppressive regimen makes long-term survival possible without obvious allograft deterioration. Cardiac transplantation should be seriously considered in patients under 55 years, who suffer from life-threatening heart failure not amenable to other modes of therapy.

Adolescent↗
PubMed1985

Mitral reconstruction.

Since 1968, the mitral valve was repaired, rather than replaced, in 647 patients. During the same period, 2,223 patients underwent prosthetic mitral replacement. Short and long-term results of mitral repair compare favorably with those after valve replacement. Five-year actuarial survival was 89% after closed commissurotomy (213 patients), 87% after open commissurotomy (203 patients) and 81% after more complex reconstructive procedures (231 patients). The operative risk was below 3% in all groups, the risk of reoperation was between 0.7% and 3%/patient year. Reconstruction was feasible in 16 patients with "floppy valve" syndrome, in 73 patients with ruptured chordae of the posterior leaflet and in 7 patients with bacterial endocarditis, with good long-term results in all of these patients. The feasibility of mitral reconstruction depends on the pliability of the anterior mitral leaflet, which may be decreased in mixed rheumatic lesions. In these patients, we would recommend prosthetic replacement of the valve. It is concluded that superior results may be achieved by mitral repair as compared to mitral replacement. However, indication and surgical technique largely depend upon the individual experience of the surgeon. The postoperative function of the reconstructed valve can be reliably assessed during the operation by left ventricular infusion of cold cardioplegic solution.

Adolescent↗
PubMed1985

[Cardiocirculatory effects of a new sympathomimetic, amezinium methyl sulfate. Results of human pharmacological studies].

Changes in haemodynamic, inotropic state, and myocardial oxygen consumption were investigated in a total of eight patients with coronary artery disease after intravenous injection of 0.07 mg/kg amezinium methyl sulfate (LU 1631, Supratonin). It was demonstrated, that the principal effects of amezinium are consistent with those of a sympathomimetic agent which stimulates vascular alpha- and beta 1-adrenoreceptors. Amezinium (0.07 mg/kg) increased cardiac index, mean arterial pressure and total systemic resistance and dp/dtmax, while there were only minor changes in stroke index, mean pulmonary pressure and total pulmonary vascular resistance. In accordance with the changes in haemodynamics there was a 21.5% increase in myocardial oxygen consumption. But there were no signs of imbalance between oxygen supply and oxygen demand.

Adult↗
PubMed1984

Response of spinal cord oxygen tension to aortic occlusion.

In order to study the factors influencing spinal cord injury resulting from occlusion of the descending aorta, the local surface PO2 (sPO2) was measured in the lumbar region (L4-5) of the exposed spinal cord after laminectomy in the pig. This is the area supplied by the arteria radicularis magna anterior (ARMA). The following aspects were considered: duration of occlusion, blood supply by the ARMA, distribution and width of spinal cord collaterals. The animals were divided into two groups. In group I (n = 7) the descending aorta was occluded immediately below the left subclavian artery; in group II (n = 7) the abdominal aorta was occluded immediately superior to the ARMA. Occlusion induced a rapid sPO2 decrease in all animals, from 29 to 3 mm Hg in group I (-14 mm Hg/min) and from 28 to 8 mm Hg in group II (-12 mm Hg/min). After 45 minutes of occlusion the blood flow through the aorta was released giving a pronounced sPO2 overshoot (36 mm Hg) about 10 minutes later. After 20 minutes there had been a return to initial sPO2 values. The results of this study confirm the hypothesis that spinal cord injury during occlusion of the descending aorta is primarily due to ischemic hypoxia/anoxia.

Animals↗
PubMed1984

Criteria for and against primary correction of Fallot's tetralogy.

The operability of tetralogy of Fallot (TOF) depends on the development of the pulmonary arteries which must be large enough to accomodate the post-repair blood flow. In contrast to later in life, this is not always true during the first 2 years. In the presence of an urgent surgical indication, therefore, the decision must be made whether to opt for primary correction or palliation. While palliation is unavoidable in patients with hypoplastic pulmonary arteries, the surgeon may choose this operation even in the presence of favorable anatomical conditions, as a result of personal experience. From 1978 through December, 1983 primary intracardiac correction of TOF was performed in 46 children, aged 4 months to 2 years (mean 13.1 months) in our clinic. Twenty-two (48%) were infants under the age of one year. Indications for operation were clinically derived from hypoxic spells or severe persistent hypoxemia. Amongst the diagnostic measures, angiographic delineation of both pulmonary arteries and the descending aorta was most important. A relationship of the diameter of the aorta (at diaphragmatic level) to the sum of the right and left pulmonary arteries: Ao.desc./(R + LPA) less than or equal to 0.6 indicated pulmonary arteries of sufficient size for primary correction, while higher values commanded palliative surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1984

A suspension of fibrin glue and antibiotic for local treatment of mycotic aneurysms in endocarditis--an experimental study.

The finding of mycotic aneurysms creates a major problem in surgery for both active bacterial endocarditis and prosthetic valve endocarditis. The value of local treatment of such aneurysms by a suspension of fibrin glue and an antibiotic was examined in an animal study since a previous in vitro investigation had indicated that such a suspension may discharge sufficient quantities of the antibiotic for up to 12 days. In 3 groups of 6 rabbits each, the entrance to the left atrial appendage was occluded subtotally. The endothelium within the cavity thus created was mechanically injured and the tip of a thin transthoracic catheter was placed in the cavity. In all animals, aliquots of staphylococcus aureus were injected through the catheter. All rabbits developed fever, and positive blood cultures were obtained in 16. The animals in group 1 were left without treatment. All 6 animals lost weight progressively, 4 animals died from sepsis, 2 rabbits were sacrificed after 6 days. Active endocarditis was demonstrated by histology and bacteriology in each animal. In group 2, 12.5 mg cephalotin were injected via the catheter 24 hours after the infection. Four animals died from sepsis, one rabbit had a positive tissue culture, and only one animal was free of infection on postoperative day 10. In group 3, 12.5 mg cephalotin suspended in fibrin glue was injected via the catheter 24 hours after the infection. All animals survived, became afebrile and resumed gain of weight. At autopsy after 10 days no infection was detectable. We conclude that a suitable antibiotic suspended in fibrin glue may allow for the sterilization of mycotic aneurysms in bacterial endocarditis.

Aneurysm, Infected↗
PubMed1984

The arteria radicularis magna anterior as a decisive factor influencing spinal cord damage during aortic occlusion.

Cross-clamping of the descending aorta immediately below the subclavian artery may result in damage to the spinal cord. Despite various protective procedures, the risk of such damage cannot be entirely eliminated. In an experimental study with 47 pigs, the influence of various factors on the genesis of spinal cord damage was examined. The pigs were divided into five groups: Groups I to IV--occlusion of the descending aorta for 45 minutes; Group I--no reduction in arterial blood pressure proximal to the site of occlusion; Group II--like Group I, plus drainage of the cerebrospinal fluid; Group III--reduction in arterial blood pressure; Group IV--like Group III, plus drainage of the cerebrospinal fluid; Group V--permanent ligation of the artery of Adamkiewicz. The degree of permanent spinal cord damage was 85.7% (Groups I to IV, six animals) and 71.4% (Group V, five animals). Thus there were no significant differences among the various groups. The frequency of spinal cord damage was independent of arterial blood pressure, intracranial pressure, and intraspinal pressure. The intracranial pressure and the intraspinal pressure were significantly dependent upon the central venous pressure but were independent of the arterial blood pressure.

Animals↗
PubMed1983

[Long-term results following resection and esophageal reconstruction in esophageal cancer].

Between 1968 and end of 1981 162 patients, aged 30 to 77 years (mean 59,9 years) underwent esophageal resection and digestive tract reconstruction for carcinoma of the esophagus and cardia. There were 102 squamous cell- and 60 adenocarcinomas which were located in 8 patients in the upper thoracic third, in 67 patients in the middle third and in 87 patients in the lower thoracic third including the cardia. Esophago-gastrostomy was performed in 138 cases whereas colon was used in 18 and jejunum in 6 cases. Overall hospital mortality was 14.8% and was reduced to 9.4% during the period from 1976 to 1981. Survival rates at two years and 5 years were 31.8% and 5.6% resp. However, for patients with seemingly "curative" resections, i.e. when the carcinoma was limited to the esophageal wall and the lymph nodes were found uninvolved, these rates were 73.2% and 23.7% resp. Follow-up studies in 103 patients revealed typical functional sequelae such as anastomotic stenosis and reflux in less than 20% of the patients. The incidence of such symptoms was higher in patients with a low subhilar anastomosis than in patients with a high supraaortic anastomosis. It is concluded that esophageal resection and reconstruction of intestinal passage for carcinoma may significantly prolong survival and may warrant a fairly acceptable quality of life. More than 70% of the investigated long-term survivors were leading a normal life also resuming an improved nutritional status.

Adenocarcinoma↗