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Biomedical subjects

L von Segesser

Publications and source records attributed to L von Segesser.

At least 91 records · Page 5Linked to original sources
PubMed1990

[Long-term results of surgical coronary vessel intervention in patients with reduced left ventricular function].

From 1975 to 1980, 112 patients with an ejection fraction below 45% underwent coronary artery bypass grafting (CABG) in the Cardiovascular Surgery Unit, University Hospital Zürich. The mean age was 35 years and the mean ejection fraction 32% (21-44%). The vast majority of patients had severe symptoms (angina pectoris or congestive heart failure). Elective surgery was performed in 62 patients (55%) and emergent or urgent in 50 (45%). All were operated on in mild hypothermia (26-30 degrees C). An average of 2.9 bypasses per patient were performed; in 57, internal mammary artery bypass was carried out for revascularization of the left anterior descending branch. - Early postoperative mortality (within 30 days of operation) was 3.6%; all deaths were of cardiac origin. Perioperative myocardial infarction occurred in 7.5% of all patients. Cumulative survival was 83% at 5 years and 68% at 9 years. Mean mortality rate/year was 3.8% with a maximum of 6.5% in the first year after operation. The incidence of angina pectoris and congestive heart failure was significantly lower after revascularization. Cumulative survival was significantly enhanced in patients with complete revascularization (91% at 5 years vs 71% for incomplete revascularization). Early postoperative mortality was especially high in urgent and emergent cases, and was higher after revascularization with internal mammary artery bypass than with venous graft. Postoperative ejection fraction was assessed in 20 patients (12 with 2- or 3-vessel disease and 8 with left main coronary artery stenosis). Ejection fraction was significantly increased only in the patient group with left main coronary artery stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

[Injuries of the large brain-feeding arteries].

Among 2923 severely injured patients in the period 1980-1988, 17 had injuries or large supraaortic arteries. The incidence was 0.58%, with an overall mortality of 53%. In 75% of survivors there was a persistent neurological deficit. We treated 5 penetrating (A. carotis 4, A. vertebralis 1) and 12 nonpenetrating (A. carotis 11, A. vertebralis 1) injuries. In all penetrating carotid injuries (4) repair was performed on admission and mortality was 50%; 1 of 2 survivors has postoperative hemiparesis. Localization of nonpenetrating carotid injuries (11) was intrathoracic (2), in the neck (7) and intracranial (2). Main complication of nonpenetrating extracranial carotid injuries is neurological deficit (7/9) due to thrombosis (3) or stenosis (4) with embolism (2). Surgery was performed in 3 cases comprising pseudoaneurysm in 2 and concomitant aortic rupture in 1. Mortality was 44%, and 80% of survivors had persistent neurological deficits. Extracranial carotid injuries (n = 13) carried a mortality rate of 83% in occluded and 29% in nonoccluded vessels (p less than 0.05). Location of carotid injury in the neck (n = 11) carried a mortality of 55%, and intracranial (n = 2) of 100% respectively. Duplex-Doppler scanning of carotid arteries is a safe, noninvasive method which is essential in blunt carotid artery trauma. Prognosis is dependent upon the size of cerebral infarction. Once neurologic deficit has been established for more than 24 hours, reconstruction of the artery should be postponed and performed only for complications (pseudoaneurysm or embolization). Clamping of arteries without hypothermic circulatory arrest or shunt should be avoided. The danger of rupture in dissection and pseudoaneurysm is slight.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Liver transplantation with atrioatrial anastomosis for Budd-Chiari syndrome.

We report the case of a young woman with Budd-Chiari syndrome in whom mesentericoval shunt was first performed, followed by transcaval liver resection and hepatoatrial anatomosis 3 years later. Liver transplantation became necessary 5 years later because of deterioarating liver function with portal hypertension and bleeding. Successful transplantation was performed with atrioatrial anastomosis with help of cardiopulmonary bypass, simplifying considerably the technical procedure and reducing dramatically blood loss.

Adult↗
PubMed1990

Noninvasive versus invasive assessment of cardiac output after cardiac surgery: clinical validation.

The accuracy of noninvasive cardiac output (CO) measurement techniques, such as electrical bioimpedance (BIO), suprasternal continuous-wave Doppler (CWD), pulsed-wave Doppler (PWD), and transesophageal continuous-wave Doppler (TED) ultrasound has been variably judged in recent years. In addition, clinical comparisons are hampered by the fact that there is no generally accepted gold standard in CO measurement. After coronary artery bypass surgery in 25 patients, CO was simultaneously determined by invasive standard techniques (thermodilution [TD] and Fick methods) plus BIO, CWD, PWD, and TED. There was an excellent agreement found between TD and the Fick method (COF = 0.13 + 1.01.COTD; r = 0.96; n = 99). Thermodilution was thus chosen to be the reference method. Bioimpedance underestimated COTD (COBIO = 0.47 + 0.60.COTD; r = 0.78; n = 111). Allowing physiological ejection times only led to an improved agreement between BIO and TD (COBIO = 0.05 + 0.69.COTD; r = 0.82; n = 79), but BIO still significantly underestimated COTD (P less than 0.0005). Using physiologic ejection times during COCWD determination reduced the scatter of data as compared with TD; however, CWD still considerably overestimated COTD, when COCWD computation was based on the echocardiographic aortic diameter (ECHO) (COCWD ECHO = 0.79 + 1.40.COTD; r = 0.84; n = 52). With the surgical aortic diameter (SURG), the agreement improved (COCWD SURG = 0.75 + 1.16.COTD; r = 0.89; n = 44), but overestimation of COTD remained significant (P less than 0.05). Irrespective of the aortic diameter, COPWD values showed a considerable scatter of data compared with COTD (COPWD ECHO = 1.26 + 0.60.COTD; r = 0.62; n = 64 and COPWD SURG = 1.42 + 0.41.COTD; r = 0.47; n = 61). Correlation of absolute COTED values to thermodilution depended on the method used for calibration. All investigated noninvasive CO measurement techniques unreliably measured relative CO changes. Despite its invasiveness, TD remains the method of choice for accurate CO determination in adult patients following cardiac surgery.

Adult↗
PubMed1990

Doppler-echocardiographic findings in a patient with persisting right ventricular sinusoids.

The Doppler-echocardiographic features of persisting right ventricular myocardial sinusoids are presented. An 18-year-old patient with persisting right ventricular sinusoids had undergone comissurotomy for critical pulmonary artery stenosis at the age of 12 months. Follow-up catheterization at the age of 17 years revealed no signs of residual pulmonary artery stenosis, outflow tract obstruction or pulmonary hypertension. No shunt could be documented. High systolic velocity jets within the myocardial sinusoids were recorded by means of continuous-wave Doppler. Pulmonary artery blood flow velocity was recorded mainly consequent to atrial contraction and was reduced during right ventricular ejection period, thus reflecting impaired systolic and diastolic right ventricular function.

Echocardiography, Doppler↗
PubMed1990

Different mobilization of calcium in endothelin-1-induced contractions in human arteries and veins: effects of calcium antagonists.

We studied the role of extra- and intracellular Ca2+ in endothelin-1-induced contractions of the isolated human internal mammary artery and vein. Veins were more sensitive to the peptide than arteries (concentration shift:3.2-fold; n = 4-10, p less than 0.05). The Ca2+ antagonists darodipine, verapamil, and diltiazem (10(-7)-10(-6) M) did not prevent the response to endothelin-1 in both vessels. In contrast, darodipine (10(-8)-10(-6) M), added after the contraction had developed, partially reversed the response in the artery (26 +/- 7%) and particularly in the vein (67 +/- 5%; n = 4, p less than 0.005 compared to the artery). Removal of extracellular Ca2+ reduced the contractions to endothelin-1 (10(-8) M) in the artery (control: 89 +/- 4% of 100 mM KCl; Ca2(+)-free: 68 +/- 4% n = 4-6, p less than 0.01), but not in the vein except at low concentrations (10(-9) M) of the peptide. After removal of intracellular Ca2+ with caffeine in the artery, endothelin-1 still evoked a contraction (17 +/- 3%, n = 3; p less than 0.005 vs. control), while in the vein the response was abolished. Thus, mobilization of Ca2+ during endothelin-1-induced contractions differs in the human internal mammary artery and vein. In the artery, the contraction depends on extracellular Ca2+, intracellular caffeine-sensitive Ca2+ stores, and a caffeine-insensitive component, while in veins, mobilization of intracellular Ca2+ is most important. Ca2+ antagonists do not prevent, but partially reverse, endothelin-1-induced contractions indicating that voltage-operated Ca2+ channels do not initiate but contribute to the maintenance of the response.

Caffeine↗
PubMed1990

Threshold concentrations of endothelin-1 potentiate contractions to norepinephrine and serotonin in human arteries. A new mechanism of vasospasm?

Endothelin-1 is an endothelium-derived vasoconstrictor peptide. Its circulating levels are below those known to evoke direct vascular effects. To study whether low concentrations of endothelin-1 potentiate the effects of other vasoconstrictor hormones, we suspended isolated human internal mammary and left anterior descending coronary artery rings in organ chambers for isometric tension recording. In mammary artery rings, the contractions to norepinephrine (3 x 10(-8) M) were potentiated by threshold (3 x 10(-10) M) and low concentrations (10(-9) M) of endothelin-1 (96 +/- 35% and 149 +/- 58% increase from control; p less than 0.01 and 0.001; n = 6). The inhibitor of endothelial nitric oxide formation L-NG-monomethyl arginine did not affect the potentiating effects of the peptide. The calcium antagonist darodipine (10(-7) M) prevented the potentiation of the response to norepinephrine evoked by endothelin-1. Similarly, contractions to serotonin (10(-7) or 3 x 10(-8) M) were amplified by endothelin-1 (3 x 10(-10) M) in the mammary (30 +/- 9%) and in the coronary arteries (59 +/- 25%). Endothelin-1 (10(-9) M) further potentiated the response (57 +/- 23% in mammary and 87 +/- 26% in coronary arteries; p less than 0.05; n = 7 and 3). The sensitivity of mammary arteries to calcium chloride was markedly enhanced in the presence of endothelin-1 (3 x 10(-10) M; concentration shift, eightfold; p less than 0.01; n = 5).(ABSTRACT TRUNCATED AT 250 WORDS)

Arteries↗
PubMed1990

Interaction between endothelin-1 and endothelium-derived relaxing factor in human arteries and veins.

Endothelin-1 is a 21-amino acid endothelial vasoconstrictor peptide that may be the physiological antagonist of endothelium-derived relaxing factor (EDRF). Endothelin-1 (10(-11)-3 x 10(-7) M) evoked potent contractions of isolated internal mammary arteries, internal mammary veins, and saphenous veins, which were enhanced in internal mammary veins as compared with internal mammary arteries (concentration shift, 6.3-fold; p less than 0.05) but not in the saphenous veins. Endothelial removal augmented the response to the peptide (at 3 x 10(-7) M) in internal mammary arteries (p less than 0.05) but not in veins. In the artery, EDRF released by acetylcholine or bradykinin reversed endothelin-1-induced contractions; in saphenous veins, both agonists were much less effective compared with the artery and veins contracted with norepinephrine (p less than 0.005-0.01). This inhibition of endothelium-dependent relaxations in veins occurred at half-maximal contractions but was most prominent at maximal contractions to the peptide. Nitric oxide similarly inhibited contractions to endothelin-1 and norepinephrine in internal mammary arteries, whereas in veins that were contracted with endothelin-1 but not with norepinephrine, the relaxations were blunted (p less than 0.005). The nitric oxide donor SIN-1 and sodium nitroprusside induced complete relaxations of internal mammary arteries but were less effective in veins contracted with endothelin-1 (p less than 0.005). Thus, in normal human arteries, EDRF inhibits endothelin-1-induced contractions, whereas the peptide specifically attenuates the effects of EDRF and nitrovasodilators in veins. This may be important in pathological conditions associated with increased levels of endothelin-1 and in veins used as coronary bypass grafts.

Acetylcholine↗
PubMed1990

[Surgical and perioperative problems of heart transplantation].

Orthotopic heart transplantation is an established treatment for terminal cardiac diseases. Close cooperation and coordination with other clinics and laboratories is mandatory to transplant a good organ with minimal ischemic time. Accurate donor evaluation and treatment is essential for fast recovery after operation. Our series is 79 orthotopic heart transplantations form 9/85 to 10/89 in 78 patients. Average ischemic time is 38 minutes in organ procurement from table to table and rises distinctly in distal heart procurement (n = 33), but is usually under 120 minutes at organ procurement from any place in Switzerland. The transplantation is performed in the technique from Lower and Shumway. Immunosuppression with triple therapy (Cyclosporin A, Azathioprim, Prednisone) and initial cytolytic therapy is well tolerated. Consequent diagnosis and treatment for rejection and infections lead to good short and medium term survival. Prophylactic treatment is indicated in high risk constellation for cytomegalovirus and toxoplasmosis infection. Early mortality (less than 30 days) was two out of seven and caused by bacterial infections. Actuarial survival is 91% at one and two years and 85% at three years with good quality of life and NYHA class I.

Heart Diseases↗
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

[Ventricular septal defect following myocardial infarct].

Surgery was performed for postinfarction ventricular septal defect (VSD) in 25 consecutive patients (14 men, 11 women; mean age 68 +/- 8 years). 9 patients were preoperatively in cardiogenic shock and required mechanical circulatory support by intra-aortic balloon pump (IABP) before surgery, whereas 11 acute patients underwent surgery without use of the IABP beforehand. The following procedures were performed: VSD patch closure in 25/25 patients, resection of infarct in 15/25, and patch enlargement of the left ventricle in 3/25. The overall 30-day mortality was 6/25 (24%). However, mortality was higher (4/9 [44%]) in the group with IABP support versus the group of acute patients without it (2/11 [18%]: p less than 0.05). In patients with significant postinfarction VSD, surgical closure appears to be mandatory.

Aged↗
PubMed1989

[Degree of arteriosclerosis of the internal mammary artery and of the coronary arteries in 45-to-75-year-old men. An autopsy study].

In the last ten years the internal mammary artery (IMA) has, thanks to its higher patency rate, been increasingly used for revascularization of the coronary arteries in preference to the saphenous vein. However, uncertainty about atherosclerosis in the IMA has continued to be voiced, and to clarify the issue we investigated post mortem the IMA and left anterior descending (LAD) coronary artery in 48 male patients who died aged 45-75 years. Six segments of the IMA and 4 of the LAD, totalling 465 histologic cross sections, were estimated quantitatively. The result was unequivocal: the tendency to stenosing intimal sclerosis is much more marked in the coronary artery than in the IMA. The IMA is not immune to intimal thickening, but even in patients with severe coronary artery disease the degree of atherosclerosis in the IMA is not of functional relevance. This fact makes the IMA the vessel of choice for coronary bypass surgery.

Aged↗
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

Retrograde internal mammary to coronary artery anastomoses.

In an effort to expand the utilization of the internal mammary artery (IMA) for revascularization of the distal coronary artery branches, distally pedicled retrograde internal mammary arteries (retro-IMA) were evaluated in 10 mongrel dogs with a mean weight of 38 +/- 13 kg. One IMA was transected at it's origin (retro-IMA) and compared to the contralateral IMA which was transected at the level of the 5th intercostal space. At a mean systemic pressure of 68 +/- 15 mmHg the mean pressure measured at the tip of the IMAs with antegrade flow was 63 +/- 14 mmHg in the retro-IMAs with retrograde flow (p less than 0.05; pressure ratio 0.8). With the same mean systemic pressure, mean antegrade free flow of the IMAs was assessed 97 +/- 43 ml/min versus 48 +/- 13 ml/min in the retro-IMAs with retrograde flow (p less than 0.005; flow ratio 0.5). Left retro-IMA to coronary artery anastomosis was performed in 6 animals to the distal left anterior descending (LAD) coronary artery and in 2 animals to the distal left obtuse marginal branch. Right retro-IMA to coronary artery anastomosis to the right posterior descending coronary artery was performed in 2 animals. The LAD coronary artery was ligated proximally to the retro-IMA to coronary artery anastomosis while the retro-IMA remained crossclamped. After documentation of significant ischemia (EKG, left atrial pressure), the crossclamp of the retro-IMA graft was removed. Subsequent normalisation of EKG and left atrial pressure occurred in all animals. We conclude that the canine retro-IMA delivers significant retrograde flow and discuss a possible use in humans.

Anastomosis, Surgical↗
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

[Blood replacement in heart transplantation].

Transfusion of blood and blood products in orthotopic heart transplantations were analysed in a series of 31 consecutive patients operated upon between September 1985 and December 1987. Mean age of the 29 men and 2 women was 41 +/- 12 years (range: 15-63). All patients had to be assigned to NYHA functional class IV before operation and their mean left ventricular fraction was 20%. The etiologies of cardiac disease leading to transplantation in this series were: cardiomyopathy in 19/31 patients (61%), ischemic heart disease in 7/31 (23%), valvular disease in 2/31 (6%), life threatening arrythmias in 2/31 (6%) and primary cardiac tumor in 1/31 (3%). Previous cardiac surgery had been performed in 6/31 patients (19%). Full anticoagulation with coumarines was observed in 24/31 patients (77%) at the time of surgery when mean PT was 33 +/- 12% and mean hematocrit was 40 +/- 4%. Mean blood products transfusion requirements in patients receiving an orthotopic heart transplant were 24.2 +/- 14.7 units (range 7-67 units) during the entire hospital stay. These figures are even higher if compiled in function of the number of donors of the transfused blood products: 29.2 +/- 22.4 (range 7-105). The following mean number of blood and blood components was perfused per patient: Red cells (hematocrit 50 +/- 10%) 4.4 +/- 3.9, concentrated red cells (hematocrit 70 + 10%) 5.9 +/- 4.3, fresh frozen plasma 7.4 +/- 3.3, platelets 3.9 +/- 4.1, and others (factor 8, 9 etc) 0.6 +/- 1.6. In-hospital mortality was 1/31 patients (3%) and actuarial survival is 27/31 (87%) at 33 months of follow-up (mean 17 +/- 7 months). However, 7/27 survivors (26%) had to be treated for cytomegaly acquired during or after the heart transplantation. Therefore transfusion of cytomegaly free blood products has to be recommended.

Adult↗