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Biomedical subjects

L K von Segesser

Publications and source records attributed to L K von Segesser.

At least 19 recordsLinked to original sources
PubMed1992

Congenital cleft of the anterior tricuspid leaflet with severe tricuspid regurgitation in adults.

OBJECTIVES AND BACKGROUND: Severe primary tricuspid regurgitation in the adult is a rare finding. This study describes the diagnostic findings and the treatment of an isolated congenital cleft of the anterior leaflet of the tricuspid valve as the morphologic substrate for severe tricuspid regurgitation. METHODS: The clinical, echocardiographic findings and the follow-up findings of five patients (all male, 20 to 56 years old) with this disorder are described. Four of the five patients underwent cardiac surgery that confirmed the diagnosis. RESULTS: In three of five patients, exertional fatigue was the limiting symptom (New York Heart Association functional classes II and III). The clinical findings included a holosystolic murmur and supraventricular arrhythmias in all patients. Cardiac catheterization, performed in four patients, yielded the incorrect diagnosis of Ebstein's anomaly in three. In one patient the cleft was associated with an atrial septal defect of the secundum type. In four of five patients successful reconstruction of the tricuspid valve with a DeVega annuloplasty was performed. One patient had a partial excision of the right atrium, and one had a closure of a coexisting atrial septal defect. One patient refused operation. CONCLUSIONS: Tricuspid valve anomalies can be accurately identified by Doppler echocardiography. Surgical repair is the treatment of choice in patients with severe tricuspid regurgitation due to a congenital cleft of the anterior leaflet of the tricuspid valve.

Adult↗
PubMed1992

[Main coronary artery stenosis: a continuous challenge].

The pre- and postoperative course in 118 patients (104 males, mean age 62 +/- 8.1, 14 females, 60 +/- 10.7 years) who underwent coronary artery bypass surgery for significant left main coronary artery disease was studied to analyze the current management and risk factors of this lesion. Of these patients 32% (38/118) remained in hospital care from the date of diagnosis (coronary angiography) until the operation. The mean interval between diagnosis and operation was 39 days (range 0-166). Twelve patients (10%) had urgent procedures (< or = 48 hours after angiography), 25 (21%) accelerated (< or = 2 weeks), 52 (44%) anticipated (< or = 2 months) and 30 (25%) elective procedures (> 2 months). There was a significant negative correlation (p < 0.001) between the grade of stenosis and the time interval from diagnosis to operation. The operation technique did not differ from the usual procedure except for the less frequent use of the internal mammary artery as arterial conduit. Patients with stable angina received an internal mammary artery graft in 65% (80/118) as compared to 26% (6/23) of the patients with unstable angina. This differs significantly from the overall rate of 95% of the patients undergoing coronary artery bypass surgery at our institution. The rate of perioperative myocardial infarction was 18% (21/118). There was no significant relation between infarction and angina class, severity of the stenosis and the use of internal mammary artery as bypass graft. The hospital mortality was 4.2% (5/118) and thus was not different from the overall mortality of (2.5%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Single cusp homograft implantation in the reconstruction of right ventricular outflow tract in the correction of tetralogy of Fallot].

From 1987 to 1990, 37 children underwent surgical correction for tetralogy of Fallot. The mean age was 38.2 months (2-156 months). The indication for right ventricular outflow tract (RVOT) obstruction in 19/37 (51%) children was: hypoplastic pulmonary valve (n = 10), annular hypoplasia (n = 12), RVOT obstruction and hypoplastic pulmonary artery (n = 10). In 18/37 (49%) children, the repair of the RVOT was done without homograft. The RVOT morphology was the only indication for reconstruction with homograft. All other pre-, intra- and postoperative data were identical for both groups. There was no operative or late death. After a mean follow-up of 4.4 months, all 19 children with homograft were in NYHA class I and echocardiographic evaluation showed mild and moderate pulmonary regurgitation in 8 and 4 children respectively. Out of the 18 children without homograft, 16 were in NYHA class I and 2 in NYHA class II. Two children had early postoperative right heart failure. The mean follow-up time in this group was 5.5 months. Echocardiography revealed residual pulmonary regurgitation in 4 children, pulmonary stenosis in 6 and combined residual pulmonary valve defect in 6. If severe malformation of the RVOT or the pulmonary artery is present, a valved homograft is recommended for repair of tetralogy of Fallot. Good morphological and functional results may be achieved.

Adolescent↗
PubMed1992

[Pericardectomy and acute infectious pericarditis].

Between 1980 and 1990 12 patients (5 male, 7 female) were operated on for acute infectious pericarditis at a mean age of 42 years. The infections were 6 bacterial (purulent 4, abscess 2), 4 tuberculous, 1 viral and 1 Candida. Pericarditis resulted from contiguous spread of infection from bilateral pneumonia in 3 patients, from subphrenic abscess in 2 and followed bacteremia in 1. Clinical signs were: tamponade/shock in 9, elevated jugular venous pressure in 11, edema in 6, hepatomegaly in 6, ascites in 1, and pericardial friction rub in 3. A preoperative pericardiocentesis in 9 patients allowed only 4 positive microbiological diagnoses and was an insufficient drainage in all cases. The preoperative mean NYHA class was 3.3. The pericardectomy was total in 9 patients and partial in 3. Total mortality was 1/12 patients (8%) with one late death due to recurrent tuberculous pericarditis. No patient with purulent pericarditis died. Another recurrence occurred 6 months after acute viral pericarditis. Atrial fibrillation in one patient was the only postoperative complication. After a mean follow-up period of 48.5 months no cardiac constriction had occurred in 11 surviving patients Actuarial survival after pericardectomy is 100% after 1 month and remains 91% after 5 years. The mean NYHA class has significantly improved to 1.2 (p less than 0.05) at the end of the follow-up. We conclude that pericardectomy combined with a specific antimicrobial therapy is a safe treatment for acute infectious and especially purulent pericarditis with low mortality and excellent longterm results. Early pericardectomy allows rapid decompression of the heart, removal of intrapericardial adhesions and infected tissue and prevents late constriction.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1992

Pericarditis constrictiva after aortic valve replacement simulating tricuspid stenosis.

Pericarditis constrictiva after cardiac surgery is rare and may occasionally lead to congestive heart failure. The case of a 29-year-old patient is described who presented with pericarditis constrictiva after aortic valve replacement with localized tamponade, causing functional tricuspid stenosis. Pericardiectomy as the treatment of choice was curative.

Adult↗
PubMed1992

Perfusion with low systemic heparinization during resection of descending thoracic aortic aneurysms.

Two series of 20 consecutive patients with aneurysms of the descending thoracic aorta (TAA) and thoraco-abdominal aorta (TAAA) underwent multisegmental aortic repair using either simple normothermic crossclamping and rapid reanastomosis (historic) or partial cardiopulmonary bypass (CPB) with heparin coated perfusion equipment and low systemic heparinization (actual). Chronic lesions were present in 14/20 patients (70%) for simple versus 13/20 (65%) for CPB (NS). Acute lesions (symptomatic less than 24 h) were present in 6/20 patients (30%) for simple versus 7/20 (35%) for CPB (NS). Dissecting lesions were observed in 4/20 patients (20%) for simple versus 8/20 (40%) for CPB (NS). Aneurysmal lesions were found in 16/20 patients (80%) for simple versus 12/20 (60%) for CPB (NS). Mean number of aortic segments (n = 8) resected was 3.2 +/- 1.1 for simple versus 4.0 +/- 1.2 for CPB (P less than 0.01). Replacement of the transdiaphragmatic aorta was performed in 10/20 patients (50%) for simple and 13/20 patients (65%) for CPB (NS). A heparin loading dose of 5000 IU for simple versus 100 IU/kg bodyweight for CPB was used. In the latter group, the activated clotting time was kept above 180 s during a mean perfusion time of 46 +/- 28 min at a mean pump flow of 2.2 +/- 0.7 l/min. Thirty-day survival for all (transdiaphragmatic) was 12/20 (5/10) patients for simple versus 20/20 (13/13) for CPB (P less than 0.002, P less than 0.01). One-year survival (all) was 11/20 patients (55%) for simple versus 19/20 (95%) for CPB (P less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Temporary lung support using an intravascular gas exchanger.

Severe respiratory failure may be difficult to overcome by conventional mechanical ventilation. As an alternative to the very demanding lung support using various modalities of extracorporeal circulation (ECMO, ECLA, etc.) we evaluated an intravascular gas exchanger (IVOX) in a "reversible" bovine model. Several degrees of hypoventilation were studied with and without intravascular gas exchange in 5 endotracheal intubated, anaesthetized, and volume-controlled ventilated animals (body weight 73 +/- 4 kg). After systematical heparinization (300 IU/kg body weight) the animals were instrumented with EKG electrodes, thermodilution pulmonary artery catheter with continuous measurement of O2-saturation, central venous and femoral arterial catheter, etc. The intravascular gas exchanger made from siliconized microporous polypropylene hollow fibres was placed in the caval veins under radiofluoroscopic control. The following scenarios were studied without and with intravascular gas exchange (gas inlet 100% O2): Normoventilation (with 14-20 strokes/min) at F10(2) 0.50 and at F10(2) 0.21; Hypoventilation (ventilator frequency reduced to 50% and tidal volume reduced to 50% of normoventilation) at F10(2) 0.50 and at F10(2) 0.21. Hemodynamics, mixed venous O2-saturation, arterial and venous blood gases, and gas-exchanger exhaust were analyzed after stabilization over 15 minutes (mean +/- standard deviation). Blood gas analyses showed significant improvement with intravascular gas exchange during hypoventilation at F10(2) 0.21: pH moved from 7.10 +/- 0.17 to 7.19 +/- 0.15*, PaCO2 moved from 9.9 +/- 4.2 kPa to 8.7 +/- 2.8*, PaO2 moved from 6.5 +/- 1.2 kPa to 7.3 +/- 0.8* and mixed venous O2-saturation moved from 33.9 +/- 16.0% to 48.1 +/- 4.6* (* = p less than 0.05 for without versus with intravascular gas exchange).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Pulmonary atresia with intact ventricular septum: results and predictive factors of surgical treatment.

Between 1970 and 1989 26 children were operated for pulmonary atresia with intact ventricular septum (PA/IVS). According to the degree of right heart hypoplasia the patients were divided into 3 groups of mild (5), moderate (17) or severe (4) hypoplasia. Palliative operations were performed in 25 children (17 male, 8 female) at a mean age of 10 days: 13 valvotomies (valv.), 5 aortopulmonary shunts, and 7 valv. plus shunt. One patient had total correction as primary procedure. A total of 17 reoperations was necessary in 12 of 26 patients (10 palliations, 7 total corrections). Total corrections were: 2 conduits and 5 patches of the right-ventricular outflow tract (RVOT). Total mortality was 14/26 (54%) children (early 10/26 = 38%, late 4/26 = 16%). After total correction mortality was 3/7 (43%) patients. After a mean follow up of 10.8 years after palliation the 12 survivors are mostly in NYHA class I. Actuarial survival after palliation was 60% after 30 days and 44% after 5 and 10 years. We analyzed 9 clinical and hemodynamic variables by univariate and multivariate analysis to assess the predictive factors of postoperative outcome. Multivariate analysis disclosed the degree of right-ventricular hypoplasia (p = 0.023) as an independent predictor for death whereas the age at palliation only approached significance (p = 0.065). We recommend the following surgical strategy, aiming in the first place at decompressing the right ventricle: in mild hypoplasia valvotomy alone or combined with a shunt for palliation, in moderate hypoplasia shunt plus patch of the RVOT and in severe hypoplasia shunting alone. In case of a restrictive foramen ovale initial balloon septostomy is performed.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1992

Valvotomy for isolated congenital aortic stenosis in children: prognostic factors for outcome.

Early and late results after surgery for isolated congenital valvar aortic stenosis were evaluated in a total of 86 children under 16 years of age (mean 7.4 years). Primary procedure was always conservative. There were 7/86 (8.1%) early deaths. All infants who died after the operation were younger than 4 months of age. Among the clinical variables tested by the univariate analysis only age and duration of cardiopulmonary bypass were significant prognostic factors for early death. There were 6/67 (7.7%) valve-related late deaths. Multivariate analysis could not identify any risk factors for early and late mortality. Actuarial survival was 97% (95% CL 93-101%) after 5 years, 94% (88-100%) after 10 years, 90% (82-98%) after 15 years, and 87% (77-97%) after 20 years. A total of 22/79 (28%) early survivors had a first reoperation and 5 had a second reoperation. Long follow-up interval was the only significant factor for reoperation. Actuarial reoperation-free interval was 91% (85-98%) after 5 years, 70% (58-81%) after 10 years, and 50% (34-64%) after 15 years. Significant factors for poor valve function were long duration of follow-up, endocarditis, and young age at operation. The probability of normal valve function was 91% (84-98%) after 5 years, 67% (55-79%) after 10 years, and 54% (40-68%) after 15 years.

Actuarial Analysis↗
PubMed1992

[Prevention of cytomegalovirus infection following heart transplantation].

Cytomegalovirus (CMV) infection after heart transplantation (HTx) is a severe complication, which leads to long treatment and hospital stay. Even if prophylactic therapy with anti-CMV IgG antibodies is performed, there is a high incidence of infection, especially when the heart from a CMV positive donor is transplanted to a CMV negative recipient (high risk constellation). This study evaluates the prophylactic antiviral therapy with ganciclovir in CMV high risk constellation at HTx. Out of 108 HTx, 29 CMV negative recipients (IgG and IgM) received a heart from a CMV positive donor (IgG pos., IgM neg.). The control group (CO) (n = 8) was treated with anti-CMV IgG antibodies (Cytotect 2 ml/kg at day 0, 1, 2, 7, 14, 21,), whereas the study group (GAN) (n = 13) was treated with ganciclovir (7.5 mg/kg single dose n = 8, or 5 mg/kg in twice daily doses n = 5 from day 1 to 14). Urea, creatinine, white blood cell count and platelet count was controlled daily. No side effects on renal and bone marrow function were noted. Therapy was well tolerated. Both groups had similar immunosuppressive protocol (prophylactic cytolysis, prednisone, azathioprine and cyclosporin A) and were similar in age, sex, preoperative diagnosis and NYHA class. Seroconversion for CMV (IgM and IgG) was observed in 75% of CO and 31% of GAN (p less than 0.05). Clinical manifestations of CMV infection started in the second month after HTx with fever in both groups CMV-organ manifestations developed in 50% (or 67% of infected) in CO (enterocolitis 2, pneumonitis 3, tonsillitis 1), and in 15% (or 50% of infected) in GAN (pneumonitis 2, epididymitis 1) NS.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[Technique and organization of heart removal from the multi-organ donor].

The orthotopic heart transplantation is an accepted treatment for terminal cardiac disease. The technique of heart procurement and preservation is explained and the primary graft function in 108 subsequent heart transplantations is assessed. The mean ischemia time is 41 +/- 10 min in local, 98 +/- 19 min in distant (< 100 km) and 114 +/- 16 min in distant (> 100 km) organ procurement. Our method of preservation consists of cold cardioplegic arrest with potassium (30 mEq/L) cardioplegic solution. The incidence of the indication for high dose katecholamine-treatment after surgery and the maximal creatininekinase levels rose with ischemia time. All hearts recovered within a few days and the stay in the intensive care unit was not prolonged. We conclude that the heart preservation with cold cardioplegic arrest results in a good primary graft function. It is important to keep the ischemia time as short as possible.

Graft Survival↗
PubMed1992

Reduction and elimination of systemic heparinization during cardiopulmonary bypass.

After extensive experimental evaluation, heparin-coated perfusion equipment was clinically evaluated with low or no systemic heparinization in three different groups of patients (n = 47). In group 1, resection of descending thoracic aortic aneurysms (n = 24) was performed with heparin-coated equipment used for left heart bypass (n = 12) or partial cardiopulmonary bypass (n = 12) for proximal unloading and distal protection (heparin 5000 IU, autotransfusion). All devices remained functional throughout the procedures and no systemic emboli were detected. The sole death (1 of 24, 4%) occurred in a patient with ruptured thoracoabdominal aortic aneurysm requiring operation in extremis. Paraparesis with spontaneous recovery occurred in one patient (1 of 24, 4%). In group 2, coronary artery revascularization randomized for low (activated clotting time greater than 180 seconds) versus full (activated clotting time greater than 480 seconds) systemic heparinization was prospectively analyzed in 22 patients. All patients recovered without sequelae, and no myocardial infarction was diagnosed. Low dose of heparin (8041 +/- 1270 IU versus 52,500 +/- 17,100 IU; p less than 0.0005) resulted in reduced protamine requirements (7875 +/- 1918 IU versus 31,400 +/- 14,000 IU; p less than 0.0005), reduced blood loss (831 +/- 373 ml versus 2345 +/- 1815 ml; p less than 0.01), reduced transfusion requirements of homologous blood products (281 +/- 415 ml versus 2731 +/- 2258 ml; p less than 0.001), and less patients transfused (5 of 12 versus 10 of 10; p less than 0.05). Lower D-dimer levels in the group perfused with low systemic heparinization (0.50 +/- 0.43 mg/L versus 1.08 +/- 0.59 mg/L; p less than 0.05) were attributed to the absence of cardiotomy suction in this group. In group 3, rewarming in accidental hypothermia by cardiopulmonary bypass was successfully performed without systemic heparinization in a patient with hypothermic cardiac arrest (23.3 degrees C) and intracranial trauma. We conclude that systemic heparinization for clinical cardiopulmonary bypass can be reduced and eliminated in selected patients if perfusion equipment with improved biocompatibility is used. Bypass-induced morbidity can be reduced.

Aged↗
PubMed1992

[Malignant ventricular arrhythmia in congenital aneurysms of the left ventricle in adulthood].

Congenital aneurysms of the left ventricle (ALV) are rare cardiac lesions. Beyond that an association with malignant ventricular arrhythmias (MVA, symptomatic ventricular tachycardia--VT or ventricular fibrillation--VF) is reported only in sporadic cases. Since 1988 we had the opportunity to study 5 patients (pts) with MVA (4 sustained VT, 1 VF; 1 female, 4 males; mean age 38 years) without cardiovascular risk factors, history of myocardial infarction, trauma or inflammatory disease. Left ventricular contrast angiography and echocardiography disclosed ALV's. At programmed electrical stimulation clinically documented MVA (4 VT, 1 resuscitated VF) were reproducible in all 5 cases, the respective VT was located in the area of the ALV in 4 cases. In 2 pts aneurysmectomy combined with subendocardial resection and cryotherapy (1 apical, 1 posterobasal ALV) was performed. In both pts histopathology confirmed a congenital disorder, without evidence of inflammatory lesions. In 2 pts MVA was controlled with antiarrhythmic therapy. The pt with VF and an ALV adjacent to the anulus of the aortic valve received an implantable cardioverter defibrillator. In congenital aneurysms of the left ventricle complicated by malignant ventricular arrhythmias surgical intervention offers a potential cure in selected cases.

Adolescent↗
PubMed1992

[Valve replacement in patients over 80 years of age].

Between January 1983 and October 1990, 20 patients age 80 years or older (mean 82 +/- 1.5 year, range 80 to 87 years) underwent valvular surgery at Clinic for Cardiovascular Surgery Zurich. The indication for operation was aortic stenosis in 19 patients, and mitral insufficiency after previous mitral valve replacement with a bioprosthesis in one. There were 15 elective operations, 2 urgent, and 3 emergency operations. Four of these patients had aortic valve replacement plus coronary artery bypass grafting. The operative mortality rate was 15% (3 patients). All patients were preoperative in NYHA classes III and IV. All survivors remained in NYHA classes I or II. The survivors have been followed from 6 to 70 months (mean 20 +/- 8 months). The actuarial survival rate at 1 and 5 years was 78.5% and 67%, respectively. Valvular replacement can be performed with increased but acceptable mortality and morbidity. Long-term results are encouraging.

Aged↗
PubMed1992

[Resorbable pericardial replacement--an experimental study].

The resorbable pericardial substitute: In modern heart surgery every patient undergoing cardiac surgery will eventually require a second operation including resternotomy. To reduce the risk of damage to the heart it has been recommended to close the pericardial sac primarily. Unfortunately there is no ideal pericardial substitute yet available. This experimental study summarizes our experience with the use of Gore-Tex Surgical Membrane and Vicryl-Collagen mesh as pericardial substitutes which have been implanted orthotopically in 12 rats. After a mean follow-up of 86 days we evaluated macroscopically the pericardial adhesions, the closure of the pericardial defect and histologically the inflammatory reaction. At explanation we found that both pericardial substitutes produce little adhesion. But in rats with Vicryl-Collagen mesh as a pericardial substitute there were only a very few inflammatory cells and total closure of the pericardial defect was in 4 out of 6 rats present. These findings suggest that Vicryl-Collagen mesh seems to be a superior pericardial substitute and also allows formation of a neopericardium.

Animals↗
PubMed1992

[Surgery of infectious pericarditis].

Between 1980 and 1990 34 patients (pat.) (21 male, 13 female) were operated for infectious pericarditis (P.) at a mean age of 48 years (min. 2, max. 70 years). The infection was acute in 12 pat. (7 bacterial, 4 Tbc, 1 viral). A chronic constrictive P. was found in 22 pat. (15 history of Tbc, 7 history of viral P.). The preoperative mean NYHA class was 3.0. Cardiac catheterization was performed in 22 pat. and confirmed restrictive pericardial disease in all cases with elevated and equalized diastolic pressures in all 4 cardiac chambers. Mean cardiac index was 2.7 l/min m2 and the ejection fraction 53%. Pericardectomy (Pe.) was performed through an anterolateral left thoracotomy in 31 pat. and through a sternotomy in 3 pat. Total and partial Pe. were performed in 31 and 3 pat., respectively. Total mortality was 3/34 pat. (8.8%) with no operative death (one early and two late deaths). There were two recurrent P. (1 Tbc, 1 viral) and no recurrent constriction. Long-time follow-up of 31 surviving pat. is known in 28 cases with a mean follow-up of 4.6 years (min. 1 month, max 10.5 years). At the end of the follow-up the mean NYHA class ist 1.3 (p less than 0.005). Actuarial survival after Pe. is 97% after 30 days and 90% after 5 and 10 years. In our retrospective study we conclude that Pe. is a safe treatment for infectious P. with low mortality and excellent long-time results with improvement of cardiac function. Pe. should be performed early for purulent or constrictive P. There is no conservative treatment for progressive myocardial constriction and the resulting cardiomyopathy. After total Pe. there is a low rate of recurrent P. or constriction.

Adolescent↗
PubMed1992

[Treatment strategy of vascular complications of acute aortic dissection].

Aortic branch occlusion may constitute the mode of presentation or become an important focus of treatment in patients sustaining acute aortic dissection. We reviewed the outcome of 187 consecutive patients (149 males and 38 females, mean age 58 yrs) with acute dissection of the thoracic aorta who were admitted and operated in our clinic during a 13-year period. We assessed the incidence, the consequences and the specific management of stenotic and obstructive lesions of the aorta and its branches. Noncardiac vascular complications occurred in 59 patients (32%); out of these complications, 38 were associated with dissection type A (incidence 28%) and 21 with dissection type B (incidence 48%). Trend towards decreasing overall surgical mortality was observed in the second part (1983-1989) of the study when compared with the first part (1977-1982): it was 28% versus 12%. Although aortic rupture and cardiac tamponade were the strongest correlate of morbidity and mortality, death specifically related to vascular complication was more common when such malperfusion occurred in the carotid, coelio-mesenteric and renal circulation. Proximal aortic repair at the site of the intimal tear with obliteration of the false lumen may have restore adequate distal circulation in 27 patients in whom improvement of the visceral or peripheral ischemia was observed after the thoracic aortic repair. Additional procedures (immediately after the thoracic repair or later on) were necessary in 15 patients to restore adequate perfusion in the compromised area. Early aggressive thoracic aortic repair followed in selected patients by additive vascular procedures can save some patients with compromise visceral or peripheric circulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗