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Biomedical subjects

G Wimmer-Greinecker

Publications and source records attributed to G Wimmer-Greinecker.

54 records · Page 3Linked to original sources
PubMed1995

Aortic valve replacement: is the stentless xenograft an alternative to the homograft? Early results of a randomized study.

From November 1992 to October 1993 we randomized 101 patients over 60 years of age undergoing elective aortic valve replacement, with or without concomitant coronary artery bypass grafting, to receive either a cryopreserved aortic or pulmonary homograft (n = 38) or a stentless porcine aortic valve xenograft (Edwards Prima 2500) (n = 63). The majority of all valves (92%) were inserted freehand in the subcoronary position. Six homografts (16%) were implanted as a free-root replacement and two xenografts (3%) were used as a mini root. There were four in-hospital deaths (4%), three in the homograft group and one in the xenograft group (homograft, 7.9% versus xenograft, 1.6%; p = not significant). Forty-one patients were followed at 3- to 6-month intervals for 9 +/- 2 months (3 to 14 months) and valve pathology was assessed routinely by means of color flow Doppler echocardiography. Two patients in the homograft group developed new aortic insufficiency grade II; all others remained with trivial or no valve incompetence. The mean gradient remained unchanged to immediate postoperative measurements (homograft, 5 +/- 1 mm Hg versus xenograft, 11 +/- 4 mm Hg; p < 0.001). Despite a slightly higher transvalvular gradient, xenografts achieved excellent initial results when compared to homografts. Ease of implantation and freedom from thromboembolism indicate that xenografts can be an acceptable alternative to homografts, particularly in older patients with small aortic annuli. Long-term studies assessing the durability of the xenograft are necessary for final evaluation.

Aged↗
PubMed1995

Aortic valve replacement with cryopreserved pulmonary allografts: five years' follow-up.

Excellent clinical results with pulmonary autografts and experimental evidence that pulmonary valves can withstand the higher stress in the systemic circulation led us to use the cryopreserved pulmonary allograft for aortic valve replacement. From September 1988 until March 1993, 126 consecutive patients (61 +/- 10 years; 74 men and 52 women) underwent aortic valve replacement with a cryopreserved pulmonary allograft. All allografts were inserted freehand in the subcoronary position. There were four in-hospital deaths (3.2%), and 1 patient had severe valvular incompetence immediately postoperatively, requiring reoperation after 4 weeks. One hundred twenty-one patients were followed up in 3- to 6-month intervals for 25.3 +/- 16.3 months (range, 6 to 66 months), and valve performance was assessed routinely by means of color-flow Doppler echocardiography. Nine patients (7.1%) died during follow-up. Two patients died of multiple septic emboli during bacterial endocarditis, and 1 patient died of a massive stroke. The other 6 patients died of myocardial infarction (4), respiratory insufficiency due to chronic obstructive lung disease (1), and carcinoma (1). Ninety-four patients (78%) had absent or trivial aortic valve regurgitation. Valvular incompetence class II was present in 3 patients (2.5%), whereas 5 others (4%) demonstrated class II to III. Severe aortic regurgitation (class III or IV) could be detected in 10 patients (8.3%). All underwent reoperation and replacement of the valve with a prosthetic device. Bacterial endocarditis caused graft incompetence in 3 patients, valve degeneration was detected in another 3, and technical mistakes at valve implantation caused valve failure in the other 4.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1994

[Use of autologous femoral vein in superior vena cava thrombosis. Case report and review of the literature].

We report on a 52-year old male patient who underwent implantation of an insulin pump because he had diabetes and in whom superior vena cava syndrome developed as a long-term complication. After unsuccessful lysis therapy superficial femoral vein was implanted to form a bypass from the internal jugular vein to the right atrium. The postoperative course was uneventful from the aspects of both the bypass and the leg after explantation of the superficial femoral vein. The bypass is still patent 7 months after the operation, and the patient has no symptoms. Autogenous superficial femoral vein can be used successfully in the reconstruction of large venous vessels. It should be the graft of choice for young patients with benign diseases. We compare our result and those obtained with different substitutes described in the literature that have been used for reconstruction in superior vena cava syndrome.

Femoral Vein↗
PubMed1994

In vivo comparison of free coronary grafts using the inferior epigastric (IEA), the gastroepiploic (GEA) and the internal thoracic artery (ITA).

The validity of alternative arterial conduits for myocardial revascularization in comparison to internal thoracic artery (ITA) has not been sufficiently defined. Evaluation of the functional in vivo vascular properties of the different conduits may be appropriate to give a perspective on long-term graft qualities. The intraoperative function of single free grafts to the left anterior descending artery (LAD) was compared in inferior epigastric (IEA, n = 13), internal thoracic (ITA, n = 12) and gastroepiploic artery (GEA, n = 12) conduits. Graft flows were measured at four points of time, 1) in situ free flow after distal dissection (IEA: 42.2 ml/min, ITA: 68.8 ml/min, GEA: 61.1 ml/min), 2) free flow following proximal grafting to the aorta (IEA: 48.1 ml/min, ITA: 63.7 ml/min, GEA: 84.2 ml/min), 3) selective graft flow after distal attachment to the LAD (IEA: 52.6 ml/min, ITA: 77.5 ml/min, GEA: 102.8 ml/min), and 4) selective LAD graft flow following paraverine (Pap) stimulation (IEA: 98.4 ml/min, ITA: 128.0 ml/min, GEA: 142.9 ml/min). Endothelium-dependent and -independent relaxation was evaluated by examination of the intraluminal graft pressures at mechanically controlled constant flow rates. Following stimulation with substance P (SP), the change of intraluminal pressure (dp) was similar in IEA (dp: -20.0 mmHg) and GEA grafts (dp: -21.1 mmHg). Only ITA conduits were less reactive to SP (-9.7 mmHg). The response to acetylcholine (ACh) could only be assessed in ITA (dp: -16.0 mmHg) and IEA (dp: -10.7 mmHg) grafts. Gastroepiploic arteries did not react on ACh stimulation (dp: +0.4 mmHg).(ABSTRACT TRUNCATED AT 250 WORDS)

Abdominal Muscles↗
PubMed1994

Mycotic aneurysms of the thoracic aorta.

Between February 1982 and December 1992 we operated on five patients (three men, two women; aged 40 to 70 years) with mycotic aneurysms of the thoracic aorta. One patient had an aneurysm of the ascending aorta, once the aortic arch and in three cases the descending thoracic aorta were involved. In four of the five patients, excision of the aneurysm and in situ reconstruction of the aorta with a Dacron graft was performed, one patient required a Dacron graft repair and aortic valve replacement. We employed deep hypothermia with circulatory arrest (2), extracorporeal circulation (1), an axillofemoral shunt (1) and a centrifugal pump (1) for cerebral and spinal cord protection. One patient died 4 months postoperatively, the other four patients were without recurrent graft infection and are free of symptoms between 20 months and 5 years postoperatively.

Adult↗
PubMed1994

The octogenarians--a new challenge in cardiac surgery?

The per- and early postoperative outcomes of 75 consecutive octogenarians (38 male, 37 female, mean age 81.7 years) who underwent open heart surgery were analysed to identify independent variables of risk factors influencing morbidity and mortality. There were 48 coronary bypasses. 20 valve replacements, and 7 combined procedures. Multivariate analysis revealed that functional class (New York Heart Association), operative procedure, aortic cross clamp time, total bypass time, and age are independent predictors for morbidity and mortality (p < 0.05). There were 6 postoperative deaths (8%). Postoperative complications included haemorrhage (2), stroke (1), unstable sternum (2), acute cholecystitis (1), pneumothorax (2), and urinary tract infection. It is concluded that octogenarians may benefit from open heart surgery at an acceptable risk.

Aged↗
PubMed1994

Coronary disease and tracheal stenosis with tracheo-oesophageal fistula: a combined surgical procedure.

A patient with coronary disease class III of the New York Heart Association and tracheal stenosis with a tracheo-oesophageal fistula, which developed after long-term intubation, is described. As both conditions were symptomatic, an aortocoronary double bypass was combined with resection of the trachea and closure of the fistula. Postoperative recovery was uneventful and the patient is symptom-free after 3 years.

Adult↗
PubMed1993

Cardiac angiosarcoma--a diagnostic dilemma.

A 25-year-old man suffering from sudden onset of haemoptysis after 1 week of orthopnoea, fatigue and general weakness was admitted to a cardiology department in Vienna. No diagnosis was made. Four weeks later cardiopulmonary resuscitation and pericardiocentesis were necessary because of cardiac tamponade. Although all modern imaging procedures were performed, a diagnosis of rapidly progressive primary cardiac angiosarcoma could not be established. Definitive diagnosis was established only after exploratory median sternotomy. The patient exhibited no response to chemotherapy. He died 5 days after surgery as a result of respiratory failure.

Adult↗
PubMed1993

[Surgical management of coronary heart disease and simultaneous carotid artery stenosis].

Simultaneous carotid endarterectomy and open-heart procedures (bypass, aortic and mitral valve replacement, arterial myxoma) were performed on 89 patients. The indication for carotid endarterectomy were either preoperative neurological symptoms (n = 36) or radiologically verified, hämodynamically relevant stenosis of more than 50-60% (n = 53). The postoperative course was uneventful in 80 patients (90%). Neurological complications occurred in 5 patients; 4 had required surgery for pre-operative neurological symptomatology and 1 of these patients died from postoperative stroke. Cardiac complications occurred in 4 patients, one of whom died because of bypass thrombosis with subsequent myocardial infarction. Many authors have different opinions regarding indication, technical procedures and optimum time of operation. We consider the simultaneous operative procedure of carotid endarterectomy and open heart procedures justified in view of the neurological complication rate of approximately 5% in our group of patients.

Aged↗
PubMed1992

Early results of cryopreserved pulmonary allografts as aortic valve substitute.

Excellent clinical results with pulmonary autografts and experimental evidence that the pulmonary valve can withstand the higher stress in the systemic circulation led us to use the cryopreserved pulmonary allograft for aortic valve replacement. From September 1988 to March 1991, 45 consecutive patients (59.9 +/- 12.0 years, 25 men and 20 women) received a cryopreserved pulmonary allograft in the aortic position from our hospital based valve bank. All allografts were inserted freehand in the subcoronary position. There were 3 in-hospital deaths (7%) and 1 patient had severe valvular incompetence immediately postoperatively requiring reoperation after 4 weeks. Forty-one patients were followed at 3-6 month interval for 14.7 +/- 7.8 months (3-28 months) and valve performance was assessed routinely by means of color flow Doppler echocardiography: 34 patients (83%) had no or trivial aortic valve regurgitation. Valvular incompetence class II was present in 2 patients (5%) whereas 3 (7%) demonstrated class II-III. Severe aortic regurgitation (class III-IV) could be detected in 2 patients (5%). Both had to undergo reoperation 4 months and 15 months, respectively, postoperatively. Macroscopic and histological evaluation of the explanted valves demonstrated absence of significant degeneration. We assume that a mismatch in size between allograft and aortic annulus could have lead to dilatation of the allograft valve ring and consequently to valvular incompetence. Pulmonary cryopreserved allografts achieve acceptable short-term results which can be improved if initial technical problems can be avoided.

Adult↗
PubMed1992

Aortic valve replacement with the pulmonary autograft--experience of 23 cases.

Since 1988 an intensive homograft-program has existed at the Linz General Hospital. We have installed an own hospital-based homograft bank, where the allografts, after a 24-hour sterilization-period in an antibiotic solution and a controlled freezing procedure, are stored in liquid nitrogen at -196 degrees C. In 1991 for the first time aortic valve replacement was performed by pulmonary autograft in 23, mainly younger, patients. Essentially our technique conforms with that of D. N. Ross, in the course of which 18 autografts were implanted in subcoronary position and 5 aortic-root replacements were performed. 3 patients died perioperatively, 2 times a severe post-operative bleeding with following hypoxemic brain damage being the cause; 3 more patients had to be rethoracotomized because of postoperative bleedings. All these were attributed to a technical difficulty, which was overcome. In one patient a left-ventricular assist device had to be installed due to a left-ventricular failure, a successful heart transplantation followed on the 8th postoperative day. A follow-up was conducted in all patients every 3 months. In 2 patients a substantial valve incompetence of grade II-III and grade III was detected, all other patients showed no regurgitation of clinical relevance. Despite our initial difficulties it is our opinion that the many advantages-no anticoagulation necessary, no valve sound, less incidence of bacterial endocarditis, and longer durability-do justify this operative procedure.

Adolescent↗
PubMed1992

[Development of arterial revascularization of the myocardium at the Linz general hospital. Personal experiences with 1000 patients].

Arterial revascularization of the myocardium, particularly the use of the internal mammary artery (IMA) as a bypass graft in coronary artery surgery has become an established procedure over the past decade. From March 1986 to June 1991, of 2070 patients who underwent coronary heart surgery at our department, revascularization of the myocardium was performed with an IMA graft in 1000 cases, whereby the percentage increased from 10.4% in 1986 to 75.0% in 1991 (p less than 0.01). The range of indications gradually widened throughout the period, age no longer being a contradiction today. One reason for this development is the substantial improvement in IMA preparation technique. No increase was found in rethoracotomy rate or in the rate of perioperative infarctions. The mean age of patients receiving an IMA graft increased from 55.2 years (1986) to 64.7 years (1991) and therefore reflects the change in ranges of indication. 54 IMA jump grafts were anastomosed, in 30 cases bilateral IMAs were used and the IMA was implanted as a free graft twice. In the future these successful results with the implementation of IMA grafts will lead to a further displacement of the saphenous vein as main bypass material.

Austria↗
PubMed1988

Sonographic changes in the endometrium of climacteric women during hormonal treatment.

Vaginal sonography of the endometrium is a new method of monitoring the effects of progestogen replacement therapy during the post-menopausal period. The advantages of transvaginal ultrasonic diagnosis are that the uterus can be seen from the fornix vaginae (that is from close range) and that the examination can be carried out whether the bladder is full or not. The differences in the thickness and structure of the endometrium, and the boundary with the surrounding myometrium, enable most of the endometrial changes that occur during the post-menopausal period to be detected sonographically. In the first group of patients we investigated, endometrial carcinoma was detected in 2 out of 60 women suffering from post-menopausal metrorrhagia, the findings subsequently being confirmed histologically. It was observed that post-menopausal women who have regular bleeding during post-menopausal hormone therapy show signs of endometrial proliferation during oestrogen therapy and of secretion during progestogen therapy.

Cell Division↗
PubMed1988

Beta-endorphin levels during the climacteric period.

Hot flushes are not caused by hypergonadotrophinaemia. This is apparent because peaks of gonadotrophin in the serum do not coincide with cutaneously measured hot flushes while such flushes still occur in hypophysectomized women. Gonadotrophin-releasing hormone and other neurotransmitters (possibly beta-endorphin) affect thermoregulation. The following hypothesis is advanced. During the climacteric period neurotransmitter changes, a decrease in catechol oestrogens, a decrease in alpha-2-adrenoceptor activity and cessation of ovarian steroid production may lead to alterations in endogenous opiate activity and thus to disturbances of thermoregulation, resulting in the occurrence of hot flushes. Low beta-endorphin levels in the peripheral plasma, which rise again following oestrogen treatment, are observed during the climacteric. On the other hand, women with severe hot flushes caused by a stress event show enormously increased beta-endorphin values, which are normalized by hormone substitution therapy acting via still unknown neuroendocrinological feedback mechanisms.

Body Temperature Regulation↗
PubMed1988

[The beta-endorphin level in climacteric women].

UNLABELLED: Hot flushes are not caused by a hypergonadotrophinemia. Peaks of gonadotrophin in the serum do not coincide with the cutaneously measured hot flushes. There is an occurrence of hot flushes in hypophysectomized women as well. GnRH and other neurotransmitters (beta-endorphin?) effect the thermoregulation. - HYPOTHESIS: During the climacteric period changes of neurotransmitters, a decrease of catecholestrogens, a decrease of alpha-2-adrenoceptor activity and the ceasing of the ovarian steroid production lead to changes of the endogenous opiate activity and thus to disturbances of the thermoregulation resulting in the occurrence of hot flushes. Low beta-endorphin levels in the peripheral plasma, which increase again after a treatment with estrogens, are found during the climacteric period. On the other hand women with severe hot flushes as an expression of a stress event show enormously increased beta-endorphin values, which normalize again after a hormone substitution therapy, effected by still unknown neuroendocrinological feedback mechanisms.

Climacteric↗
PubMedDate not supplied

Complications of port-access cardiac surgery.

Port-Access cardiac surgery is a recent technology that is undergoing rapid development. The learning curve associated with this technique is a challenge even for the skilled and experienced cardiac surgeon. Mainly because of femoral cannulation, the use of guidewires, and working through small incisions, Port-Access cardiac surgery contains certain pitfalls that are clearly associated with the technology involved. These pitfalls currently require troubleshooting, but as the technology progresses, this may become less of an issue. Communicating these pitfalls to others is important to help others to avoid or better manage complications and to contribute to improving the technology of Port-Access techniques.

Cardiac Surgical Procedures↗
PubMedDate not supplied

The micro-mitral operation comparing the Port-Access technique and the transthoracic clamp technique.

BACKGROUND: Several minimally invasive approaches to the mitral valve have been described, including parasternal incision and right anterolateral thoracotomy. MATERIAL AND METHODS: Since September 1996, 58 patients underwent minimally invasive mitral valve surgery at our institution through a right anterolateral minithoractomy. Two different techniques were used for institution of cardiopulmonary bypass (CPB) and aortic clamping: in the Port-Access group (group A) patients had femoro-femoral cannulation with a special arterial cannula to introduce an endoaortic balloon clamp (n = 23). The second group (group B) of patients underwent femoro-femoral CPB as well in combination with a specially designed transthoracic aortic clamp (Chitwood technique, n = 35). Patients were assigned to either technique in a nonrandomized fashion. Demographics were similar in both groups. RESULTS: In group A, 4 valves were replaced, 19 patients had mitral valve repair. In group B, 7 patients had valve replacement and 28 patients underwent mitral repair. Four patients in group A were converted to Chitwood technique due to endoclamp dysfunction. Operating time, CPB time, cross-clamp time, and postoperative blood loss were lower in group B (operating time 295 +/- 83 min vs. 236 +/- 63.9 min; CPB min 167.6 = 64.9 min vs. 137.6 +/- 38.2 min; cross-clamp time 105.9 +/- 51.7 min vs. 78.9 +/- 25.2 min; postoperative blood loss 584 +/- 428 mL vs. 323 +/- 209 mL [p < 0.05]). Clinical outcome regarding postoperative mechanical ventilatilation time, hospital stay and hospital mortality was not different between groups. CONCLUSIONS: Minimally invasive mitral valve procedures via right anterolateral minithoracotomy, including complex valve repair, can be performed successfully using either technique. However, the Chitwood technique provides better intraoperative handling with shorter operation time and less postoperative blood loss. Additionally, costs of a procedure are less using the Chitwood technique compared to the Port-Access technique.

Adolescent↗