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Biomedical subjects

R Siebenmann

Publications and source records attributed to R Siebenmann.

At least 37 records · Page 2Linked to original sources
PubMed1989

[Results of the initial 50 heart transplantations in Zurich].

During the first 40 months of the new Heart Transplantation Program (September 1985 until December 1988) a total of a 160 patients were evaluated for transplantation at the University Hospital in Zurich. 50 patients eventually came to heart transplantation, while one patient underwent a heart-lung transplant. In the same period 9 patients accepted for transplantation died on the waiting list before transplantation. All 50 hearts were transplanted orthotopically. Follow-up treatment, immunosuppression and diagnostics for rejection are described. There was no operative mortality in this group. Two patients died early and three died late. For the first consecutive 50 heart transplant patients, showing a total of 732 patient months, actuarial survival was calculated at 90.1% at one and two years, and at 79.5% at three years. "Enlarged Heart Transplantation Program" describes some of the secondary activities spurred by the new Heart Transplantation Program.

Actuarial Analysis↗
PubMed1989

Late failure of systemic ventricle after atrial correction for transposition of great arteries.

The incidence of late systemic ventricular failure (SVF) was determined in 220 early survivors of atrial correction for transposition of great arteries (TGA), operated upon between 1964 and 1985. SVF was defined as either severe heart failure (NYHA class III or IV) or death due to the same cause, in the absence of other haemodynamic disturbances. The actuarial survival rate was 96% after 1, 94% after 5 and 87% after 10 years. SVF occurred in 16/220 patients (7.2%). SVF was more common in complex TGA (TGA + VSD or PS or both) with 11/99 patients (11%) than in simple TGA with 5/121 patients (4.1%), P less than 0.01. Actuarial freedom from SVF was 97% at 5, and 92.5% at 10 years. SVF caused 10/25 (40%) late deaths. SVF occurred from the 1st postoperative year up to 20 years after correction (average interval 6.3 years). In 1 of 2 patients a systemic atrioventricular (AV) valve annuloplasty did not improve SVF. Heart transplantation was performed in 2 patients and 1 is on the waiting list. SVF is a rare late complication of atrial correction for TGA with a constant incidence in the late course. SVF is more common in complex TGA.

Actuarial Analysis↗
PubMed1989

Postinfarction ventricular septal defect--surgical strategies and results.

Twenty consecutive patients with postinfarction ventricular septal defect (VSD) were subjected to surgery: there were 8 females and 12 males with a mean age of 67 +/- 9 years. Nine acute patients developed cardiogenic shock, and intra-aortic balloon pump was started before surgery (with IABP). Eight acute patients showed preoperatively relatively stable hemodynamics, and surgery was feasible without previous use of the intra-aortic balloon pump (without IABP). The interval between myocardial infarction and surgery was 13 days for 17 acute cases. In the group with IABP the interval was 8 +/- 5 days versus 19 +/- 11 days in the group without IABP (p less than 0.025). VSD patch closure was performed in 20/20, resection of infarct in 10/20, transventricular approach without resection of infarct in 3/20, patch enlargement of the left ventricle in 2/20, plicature of an aneurysm in 3/20, aorto-coronary bypass in 10/20 (number of bypasses: 2.1 +/- 1.3) and mitral annuloplasty in 1/20. The perioperative 30 days mortality was 5/20 (25%) for the whole series. In the group with IABP mortality was 4/9 (44%) versus 1/8 (13%) in the group of acute patients without IABP (p less than 0.05). Mean follow-up for the 15 surviving patients was 1.7 +/- 1.0 years. Two patients died during the first year, one of them due to carcinoma. After 1 year, mean NYHA functional class was assessed 1.5 +/- 0.6. One patient showed a residual VSD which was closed surgically. Immediate closure of a postinfarction ventricular septal defect is the therapy of choice of this complication of acute myocardial infarct with a natural history showing an extremely high mortality.

Aged↗
PubMed1989

Internal-mammary coronary artery grafts: is their superiority also due to a basically intact endothelium?

The internal mammary artery (IMA) is a superior conduit for coronary artery revascularization and many factors have been suggested for explanation of this superiority. IMA and saphenous vein grafts have been systematically analysed with scanning electron microscopy (SEM) in a series of 11 patients undergoing coronary artery revascularization. At the time of implantation endothelial damage is almost absent in internal-mammary-artery (IMA) grafts; small areas of exposed subendothelial matrix may be present but are essentially non-thrombogenic as reflected by the lack of clots in these areas. In contrast the endothelium of harvested human saphenous veins (SV) shows large thrombogenic defects with exposed collagenous fibrils. The extent and deepness of the defects deteriorated in the period between removal of the vein and its attachment to the aorta. We conclude that long-term superiority of IMA grafts may also be due to the lack of primary intimal defects.

Adult↗
PubMed1989

Endothelium-derived relaxing factor and protection against contractions induced by histamine and serotonin in the human internal mammary artery and in the saphenous vein.

We investigated the release of endothelium-derived relaxing factor (EDRF) in response to serotonin and histamine in the human internal mammary artery and saphenous vein. The arteries and veins were obtained intraoperatively and were suspended in organ chambers to record isometric tension. In mammary arteries, histamine (10(-8) to 3 X 10(-6) M) induced relaxations in rings with (70 +/- 5%, IC50, 6.5 +/- 0.2) but not without endothelium (p less than 0.005 for rings with compared with those without endothelium, n = 7-10). The response was inhibited by methylene blue or hemoglobin, but not meclofenamate, and, therefore, EDRF was delineated as the mediator. Because chlorpheniramine but not cimetidine inhibited the response, EDRF was released by the H1-histaminergic receptor (n = 5-8). In contrast, in saphenous veins, histamine caused only weak or absent endothelium-dependent relaxations, but contractions were enhanced in rings with endothelium (p less than 0.05, n = 6). Serotonin did not induce endothelium-dependent relaxations, but contractions were markedly greater in veins compared with arteries (p less than 0.005, n = 6). The endothelium inhibited the maximal contraction to serotonin in arteries (p less than 0.034) but not in veins. Thus, EDRF protects against contractions induced by histamine and serotonin in the mammary artery but not in the saphenous vein. This may be important for improved graft function and patency of the artery compared with that of the vein.

Endothelium, Vascular↗
PubMed1989

Lethal air embolism during arthroscopy. A case report.

We report a case of lethal air embolism during diagnostic arthroscopy using air to distend an acutely injured knee. Air had escaped from the joint through an intra-articular fracture and entered the venous system. During arthroscopy, pressure within the joint may be 5 to 10 times higher than venous pressure, so any medium may escape. We advise that the use of air, especially in freshly injured joints, should be abandoned in favour of saline or carbon dioxide.

Adult↗
PubMed1989

Late functional deterioration after atrial correction for transposition of the great arteries.

Late anatomic and functional results were evaluated in 220 consecutive survivors who underwent surgery in 1964-1984 for atrial correction of transposition of the great arteries (TGA). Actuarial survival was 87% at 10 years and 83% at 20 years and was higher in patients with simple than in those with complex TGA (92% vs. 84% at 10 years). Although 83% of simple TGA and 78% of complex TGA survivors belong to the oligosymptomatic or asymptomatic group, failure of the systemic ventricle occurred in 17 (7.7%) patients. This failure was more common in patients with complex than in those with simple TGA (12.1% vs. 4.1%, p less than 0.05); actuarial incidence of such failure was 3% at 5 years and 11% at 15 years, and it caused 10 of 25 (40%) of late deaths. Late dysrhythmias necessitating pacemaker implantation had an incidence of 9.8% at 10 years. Reoperations were performed in 20 (9.1%) patients, with 12 of 23 (52%) reoperations occurring in the first 2 years after correction. Stenosis of caval inflow (eight patients), or residual atrial or ventricular septal defects (eight patients) were the most common causes of reoperation. Systemic atrioventricular valve incompetence necessitating surgery occurred in only three patients. Atrial correction gives good late results, but late functional deterioration occurs in some patients.

Child↗
PubMed1989

[Clozapine-induced cholestatic jaundice: a case report].

We report on a patient who became jaundiced during treatment with clozapine (Leponex). Histologically, cholestatic hepatitis with single-cell necroses of hepatocytes and infiltration of the portal zones with eosinophilic granulocytes were found. The patient recovered after discontinuation of clozapine, and liver function tests returned to normal within 4 weeks. This adverse effect of clozapine suggests that this "atypical" tricyclic neuroleptic resembles the phenothiazines both with regard to therapeutic spectrum and side effects.

Aged↗
PubMed1989

[Surgery of traumatic aortic rupture].

This report describes the clinical presentation, diagnosis, surgery and results of patients with acute traumatic rupture of the aorta in a series of 21 consecutive patients. Direct cross-clamping without additional methods of spinal cord protection was used in 18/21 patients (86%). Direct suture was possible in 12/21 patients (60%). In the remaining patients, the repair was carried out by interposition of a Dacron graft. Overall mortality was 7/21 patients (33%). However, in 3 patients with severe polytrauma irreversible brain damage was the cause of death whereas 2 patients died from septicemia and myocardial infarction, respectively. No paraplegia nor paraparesis occurred in the surviving patients which were operated by direct cross-clamping of the aorta and rapid reanastomosis without additional methods of spinal cord protection.

Adolescent↗
PubMed1988

[Endothelium-derived relaxing factor(s): endogenous nitrates in the circulation?].

Endothelial cells release a potent vasodilator which activates guanylate cyclase and thereby induces relaxation of vascular smooth muscle cells. The so-called endothelium-derived relaxing factor (EDRF) is released by acetylcholine, local and circulating hormones, and substances released from aggregating platelets or formed during activation of the coagulation cascade. Nitric oxide (NO) probably accounts for the factor's activity. Thus, endothelial cells produce endogenous nitrates causing vasodilatation and inhibition of platelet adhesion and aggregation. Under physiological conditions, EDRF may play a role in the prevention of vasospasm and thrombosis. On the other hand, the impairment of endothelial regulatory mechanisms in atherosclerosis and hypertension may be involved in the pathogenesis of vascular occlusion and thereby of myocardial infarction, stroke and peripheral vascular disease.

Acetylcholine↗
PubMed1988

Difference between endothelium-dependent relaxation in arterial and in venous coronary bypass grafts.

Both the internal mammary artery and the saphenous vein are used to construct coronary-artery bypass grafts. We hypothesized that the release or production of endothelium-derived relaxing factor, which regulates blood flow and inhibits platelet function, may differ in venous and arterial grafts. We therefore studied endothelium-dependent relaxation in internal mammary arteries, internal mammary veins, and saphenous veins obtained from 58 patients undergoing coronary bypass surgery. Vascular rings with and without endothelium were suspended in organ chambers, and isometric tension was recorded. Acetylcholine (10(-8) to 10(-4) M), thrombin (1 U per milliliter), and adenosine diphosphate (10(-7) to 10(-4) M) evoked potent endothelium-dependent relaxation in the mammary artery but weak response in the saphenous vein (P less than 0.005; n = 6 to 27). In the mammary artery, relaxation was greatest in response to acetylcholine (86 +/- 4 percent reduction in norepinephrine-induced tension), followed by thrombin (44 +/- 7 percent) and adenosine diphosphate (39 +/- 8 percent). In the saphenous and mammary veins, relaxation was less than 25 percent. Relaxation was unaffected by indomethacin but was inhibited by methylene blue and hemoglobin (P less than 0.005 and 0.01, respectively), which suggests that endothelium-derived relaxing factor was the mediator. Endothelium-independent relaxation in response to sodium nitroprusside was similar in arteries and veins. We conclude that endothelium-dependent relaxation is greater in the mammary artery than in the saphenous vein. The possibility that this contributes to the higher patency rate among arterial grafts than among venous grafts will require further study.

Acetylcholine↗
PubMed1988

[Inflammatory abdominal aortic aneurysm].

348 cases of abdominal aortic aneurysm were reviewed for typical features of inflammatory aneurysm (IAAA) (marked thickening of aneurysm wall, retroperitoneal fibrosis and rigid adherence of adjacent structures). IAAA was present in 15 cases (14 male, 1 female). When compared with patients who had ordinary aneurysms, significantly more patients complained of back or abdominal pain (p less than 0.01). Erythrocyte sedimentation rate was highly elevated. Diagnosis was established in 7 of 10 computed tomographies. 2 patients underwent emergency repair for ruptured aneurysm. Unilateral ureteral obstruction was present in 4 cases and bilateral in 1. Repair of IAAA was performed by a modified technique. Histological examination revealed thickening of the aortic wall, mainly of the adventitial layer, infiltrated by plasma cells and lymphocytes. One 71-year-old patient operated on for rupture of IAAA died early, and another 78-year-old patient after 5 1/2 months. Control computed tomographies revealed spontaneous regression of inflammatory infiltration after repair. Equally, hydronephrosis due to ureteral obstruction could be shown to disappear or at least to decrease. IAAA can be diagnosed by computed tomography with high sensitivity. Repair involves low risk, but modification of technique is necessary. The etiology of IAAA remains unclear.

Aneurysm, Infected↗
PubMed1988

[Treatment and follow-up care after heart transplantation].

Today survival rates after heart transplantation of around 80% at 1 year and around 65% at 5 years are realistic. Most patients attain NYHA functional class I. Due to progress in donor and recipient selection, in immunotherapy, and in a systematic follow-up program post transplant, heart transplantation today has become an accepted treatment in special forms of terminal heart disease. Between September 23, 1985, and May 15, 1987, 19 patients were transplanted in Zurich. After an average of 7 months (1-20), 18 patients are alive with NYHA functional class I. The follow-up program checks systematically for the three main problems post transplant (rejection, infection, and drug-induced side-effects). Regular endomyocardial biopsy is the gold standard for diagnosis of rejection. Non-invasive methods, such as cyto-immunological monitoring, neopterin, or beta 2-microglobulin, are not a substitute but valuable adjunctive diagnostic methods.

Adult↗
PubMed1988

Outcome and risk factors in surgery of descending thoracic aneurysms.

In a series of 100 consecutive patients operated upon for aneurysmatic lesions of the descending thoracic aorta, the mean age was 52 +/- 16 years (male = 81, female = 19). There were 31 dissections (acute 10, chronic 21); 28 post-traumatic aneurysms (ruptured 5, acute 7, chronic 16); 22 arteriosclerotic aneurysms (ruptured 1, chronic 21); 11 thoracoabdominal aneurysms, 5 anastomotic aneurysms and 3 mycotic aneurysms. No symptomatic patient was refused. Preoperative risk factors were graded on a scale of 6 by counting 1 point for each of the following elements: central nervous system disease; heart, pulmonary, and renal disease; arterial hypertension, age greater than 60. In-hospital mortality and paraplegia for the whole series were 25% and 7% respectively. In acute dissection, the mortality was 6/10 patients versus 2/21 in chronic events. In post-traumatic aneurysms, mortality was 2/5 in ruptured, 2/7 in acute and 0/16 in chronic events. In arteriosclerotic aneurysms, mortality was 1/2 in ruptured and 6/20 in chronic events. In thoracoabdominal aneurysms, mortality was 5/11, in anastomotic 1/5 and in mycotic 0/3 patients. The mean number of risk factors in non-survivors versus survivors was significantly higher in acute dissection, chronic dissection, chronic arteriosclerotic aneurysms and thoracoabdominal aneurysms. Rupture and acute events are related to a high surgical mortality. Non-survivors appear to have significantly more preoperative risk factors.

Adolescent↗
PubMed1988

Testosterone-secreting adrenocortical tumor in a pubertal girl. Case report and review of the literature.

A girl aged 12 years and 10 months presented with deepening of the voice first noted 7 months earlier. Pubertal development was almost completed. The girl had regular monthly menses and no signs of hirsutism, clitoris enlargement or Cushing's disease. Serum testosterone was about threefold above normal, whereas dehydroepiandrosterone was in the upper normal range. The 17-ketosteroids as well as the gas-chromatographically analyzed 5 alpha and 5 beta derivatives of testosterone from urine were slightly increased. Other serum and urinary steroids were normal. Dynamic tests of the endocrine function exhibited inconclusive results. Ultrasonography revealed no ovarian cysts. A small, left-sided adrenal mass was identified by computed axial tomographic scan and removed by surgery. There were no signs of local metastasis nor of vascular extension. The histopathological diagnosis was adrenocortical carcinoma. 5 months after surgery, the preoperatively elevated steroid levels had returned to normal.

Adolescent↗