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Biomedical subjects

L von Segesser

Publications and source records attributed to L von Segesser.

At least 109 records · Page 6Linked to original sources
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

[Isolated rupture of an iliacus aneurysm].

A retrospective analysis of 23 patients with isolated iliac aneurysms is presented. The age of the 23 men ranged from 49 to 89 years (mean +/- SE: 72.2 +/- 8.4 y). All patients had pain, nineteen (83%) were in shock, in only 11 (48%) an abdominal mass was palpable. Fifteen (65%) of the aneurysms were located in the common iliac artery, 5 (22%) in the internal and 3 (13%) in the external iliac artery. Their diameter ranged from 3 to 12 cm (mean +/- SE: 7.8 +/- 2.6 cm). Resection with an unilateral graft interposition was done in 12 (52%), a Y-graft implanted in 8 (35%) and an endoaneurysmorrhaphy of the internal aneurysm performed in 2 patients. Early mortality was 22% and was not statistically different from the 28.6% mortality in ruptured abdominal aneurysm resections performed in the same time. Because of the substantial risk of rupture with high mortality elective operative intervention should be considered for isolated iliac aneurysms with a diameter more than 3 cm.

Aged↗
PubMed1989

[Development of a small-lumen vascular prosthesis coated with autologous endothelial cells].

A new compliant prosthesis with a monolayer of autologous endothelial cells (ENC) has been developed. It consists of a porous polyurethane-siloxane-copolymer reinforced by a polyester network to prevent excessive dilatation. On the inner surface an ENC monolayer is established before implantation by a cell culture procedure. The prosthesis displays compliance (13.2 +/- 3.0 x 10(-4) mmHg-1) comparable to native arteries. It is non-kinkable (minimal radius of curvature less than 5 mm). Burst resistance, remaining deformation, cut out force and tensile strength are superior to standard values. ENC-coverage in excess of 95% of the inner surface was produced in vitro using a lining procedure. The monolayer of confluent cells was demonstrated to consist of endothelial cells by their characteristic cobblestone morphology, the expression of factor VIII related antigen and the specific uptake of Dil-Ac-LDL. The unstimulated prostacyclin production was similar both in native veins as well as in lined prostheses. Antithrombogenicity of the endothelial cell lining was demonstrated in 24 h animal implants.

Animals↗
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

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

Acute complications of elective coronary angioplasty: a review of 500 consecutive procedures.

In 500 consecutive procedures of elective coronary angioplasty attempted at a centre with a primary success of 86%, one or more major acute complications occurred in 34 cases (6.8%). Twenty four patients (4.8%) sustained an acute myocardial infarction (in six this was despite emergency coronary artery bypass surgery) and two patients (0.4%) had emergency coronary bypass without myocardial infarction. Ventricular fibrillation was a complication without sequelae in five (1.0%) patients; one (0.2%) patient died because of refractory ventricular fibrillation and ensuing electromechanical dissociation. "Benign" coronary artery rupture occurred in one (0.2%) patient, and one (0.2%) patient had elective coronary surgery to retrieve the tip of a fractured guide wire after an otherwise successful angioplasty. Despite a low mortality, coronary angioplasty is associated with major complications in about one of 14 procedures; the complication is usually acute myocardial infarction caused by occlusion of the vessel.

Adult↗
PubMed1988

Valvuloplasty with trefoil and bifoil balloons and the long sheath technique.

The experimental and early clinical experience with percutaneous valvuloplasty using trefoil and bifoil balloon catheters (Schneider Shiley) and a long introducer sheath with a new back-up wire are reported. The trefoil balloon consists of three and the bifoil balloon of two angioplasty balloons mounted in parallel on a single catheter. Inflated, they form a rosette allowing for some blood flow through the spaces between the individual balloons. These small balloons are more pressure tolerant than one large balloon. The hemodynamic advantage of these balloons compared to single balloons could be demonstrated in animal experiments (healthy valves and surgically created stenoses). In 31 consecutive patients with trefoil-bifoil balloon valvuloplasty, there was no inhospital mortality. The results of trefoil valvuloplasty in twelve patients with pulmonary stenosis compared favorably to those of patients treated with single balloons. There were no technical failures or complications. There were two unsatisfactory results (severely dysplastic valve). In the aortic valve, the results with calcified stenoses were satisfactory at first but disappointing during follow-up. There were no technical failures but one of nine patients suffered an embolic myocardial infarction. In the mitral valve, there were two failures (one deficient equipment, one stroke during balloon positioning). In one case, insufficient balloon size led to an inadequate result. One patient needed surgical drainage for a pericardial tamponade. In two patients, mitral regurgitation was significantly increased. A 17F long sheath was developed to further facilitate balloon valvuloplasty. It guides the balloon catheter across the valve (and across the septum in case of the mitral valve), stabilizes it during inflation, and serves as a second pressure line to continuously monitor the transvalvular pressure gradient. It prevents bleeding at the puncture site during the intervention and presumably reduces the trauma to the artery. Because of its thrombogenic potential, heparinization of the patients is essential. The largest balloon accepted by the sheath is a 2 X 19 bifoil balloon which was the reason to use a bifoil balloon in some mitral valves. Trefoil balloons put in place through a long sheath provide some theoretical advantages over conventional single balloons introduced over guidewires that need to be evaluated by larger clinical studies. Although they do not prevent circulatory collapse during initial inflation in tight stenoses, they permit transvalvular flow when fully unfolded.

Aged↗
PubMed1987

Comparison of multivessel coronary angioplasty with surgical revascularization with both internal mammary arteries.

To evaluate medium-term clinical results of two major methods of myocardial revascularization, we compared 80 consecutive patients with multivessel percutaneous transluminal coronary angioplasty (PTCA) with 80 consecutive patients with coronary surgery using both internal mammary arteries in all and additional venous grafts in some. Patients in the surgical group had a higher extent of coronary artery disease. In patients with PTCA a mean of 2.2 vessels per patient were attempted, and in patients with surgery 2.7 distal anastomoses per patient were performed. Primary success for PTCA and surgery was 86% vs 94% and complications occurred in 7% vs 6%, respectively. Control angiograms, done in 86% of patients (59/69) after successful PTCA, showed a recurrence in 42% (25/59). Repeat PTCA was done in 15, elective surgery in seven, and a medical treatment was pursued in 3% patients with restenosis. Recurrence of symptoms after successful surgery was found in three patients (4%). They were treated with PTCA. Clinical follow-up was available for all patients, at a mean of 12 +/- 6 months after PTCA and 16 +/- 9 months after surgery. Mean improvement was 1.5 NYHA functional classes after successful PTCA and 2.1 after surgery; 60% (48/80) vs 89% (48/80), respectively, were in class I (p less than .0001). There were fewer PTCA patients than surgical patients without antianginal drugs at follow-up (19% [11/58] vs 37% [18/48]; p less than .05), and their double product during exercise testing was inferior (272 +/- 56 vs 295 +/- 47 mm Hg X beats/min/100; p less than .05). Medium-term clinical outcome appears better after successful surgery with both internal mammary arteries than after successful multivessel PTCA.

Adult↗
PubMed1987

Repeat sternotomy after reconstruction of the pericardial sac with glutaraldehyde-preserved equine pericardium.

The risk of repeat sternotomy is higher than that of the initial sternotomy, especially if the pericardial sac was left open at the first intervention. In 200 consecutive patients with a pericardial defect after open heart operations, the pericardium was closed with a glutaraldehyde-preserved equine pericardial patch. Precardiac adhesions at reoperation were assessed in four groups of patients on a scale of 6, ranging from 0 (no adhesions) to 5 (calcified or ossified adhesions). Group I comprised 13 patients in whom the pericardium was left open at the first operation and an equine pericardial patch was implanted at reoperation. Group Ia included the first five Group I patients who underwent reoperation less than 1 year (early reoperation) after the initial procedure. Group Ib included the other eight patients of Group I, who underwent reoperation more than 1 year (late reoperation) after the first procedure. Group II comprised nine patients who were reoperated on after reconstruction of the pericardial sac with a glutaraldehyde-preserved equine pericardial patch. After a mean follow-up of 20.2 months, the incidence of patch-related complications was 1%. Statistical analysis shows less severe adhesions on reoperation in Group II patients (pericardial defect patched) than in Group I patients (pericardial defect left open): mean grade of adhesions 1.6 +/- 0.9 (Group II) versus 3.2 +/- 0.6 (Group I), p less than 0.001. Precardial adhesions with the pericardium left open were similar in patients having early and late reoperations: mean grade of adhesions 3.0 +/- 0.7 (Group Ia) versus 3.4 +/- 0.5 (Group Ib), no significant difference. Therefore, the glutaraldehyde-preserved equine pericardial patch can be considered a suitable material for primary closure of the pericardial sac in patients with inadequate autologous pericardium.

Adolescent↗