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Biomedical subjects

R Körfer

Publications and source records attributed to R Körfer.

At least 19 recordsLinked to original sources

Mechanical circulatory support: the Bad Oeynhausen experience.

From September 1987 to February 1994, we treated 147 patients ranging between 11 and 82 years old with different mechanical circulatory support systems. The applied devices were the Bio-Medicus centrifugal pump in 61 patients, the Abiomed BVS System 5000 in 49 patients, the Thoratec ventricular assist device in 42 patients, and the Novacor left ventricular assist device in 7 patients. On the basis of indication for mechanical circulatory support, the patients were divided into three groups: group 1 consisted of 72 patients with postcardiotomy cardiogenic shock; group 2, 50 patients in whom mechanical support was used as a bridge to cardiac transplantation; and group 3 (miscellaneous), 25 patients in cardiogenic shock resulting from acute myocardial infarction (n = 14), acute fulminant myocarditis (n = 3), primary graft failure (n = 2), right heart failure after heart transplantation (n = 3), and acute rejection (n = 3). Time of support ranged from 1 hour to 97 days (mean duration, 10.8 days). Seventy-five patients (51%) were discharged from the hospital. The best survival rate was achieved in group 2 with 72%, followed by group 1 with 44% and then group 3 with 28%. The most frequent complications in group 1 were bleeding (44%), multiple-organ failure (24%), neurologic disorders (18%), and acute renal failure (15%). In group 2, the major complications were bleeding (34%) and cerebrovascular disorders (22%) and in group 3, multiple-organ failure and sepsis (60%) and bleeding (32%).

Adolescent

[Non-Hodgkin's lymphoma with heart, mediastinum and lung hilar involvement].

We performed an exploratory thoraco-, pericardio- and cardiotomy in a 70-year-old male patient suffering from a biatrial tumor after a thorough diagnostic procedure had failed to reveal the correct diagnosis. Histologically, the tumor proved to be a centrocytic-centroblastic non-Hodgkin-lymphoma. This case demonstrates the diagnostic difficulties in cardiac involvement of lymphomas and presents the therapeutic options.

Aged

Emotional adjustment and perceived locus of control in heart transplant patients.

Orthotopic heart transplantation has been established as a routine clinical operation. In this study, we were interested in: (a) how patients cope emotionally with the situation pre- and postsurgically, especially with regard to anxiety and depression; and (b) whether the patient's perceived locus of control is related to emotional adjustment before and after heart transplantation. Twenty patients who were on the waiting list for heart transplantation with highest priority provided complete psychological questionnaires presurgically and 20 days after surgery when intensive care was no longer required. During the waiting period, patients rated high on depression, state and trait anxiety in comparison with healthy references while ratings on perceived locus of control scales were within the norm ranges. After surgery, heart transplant patients experienced significantly less state/trait anxiety and depression reaching levels which were no longer statistically different from health references. While postsurgical ratings of anxiety (state and trait) and depression were not significantly correlated with presurgical ratings, both were closely related to ratings of locus of control. Belief in powerful others was positively correlated with pre- and postsurgical anxiety and depression. Chance control orientation was related only to presurgical emotional disturbances. It can be concluded that emotional adjustment after heart transplantation is more likely to be predicted by presurgical ratings of locus of control than by presurgical emotional adjustment.

Adaptation, Psychological

Effects of temperature and sodium on myocardial and hepatocellular fatty acid uptake.

Fatty acid influx into human myocardium was studied in 15 patients during the cooling phase of cardiopulmonary bypass at myocardial temperatures of 37 degrees to 25 degrees C. The fitting of the data to a functional relation, developed in this study, revealed fatty acid influx to be a temperature-dependent saturable process corresponding to a Michaelis-Menten constant (Km) at 37 degrees C of 0.26 +/- 0.084 mumol/g, a maximal fatty acid influx velocity (Vmax) at 37 degrees C of 0.28 +/- 0.045 mumol/g per minute, activation energy for fatty acid binding to the putative carrier (E) of 23.8 +/- 5.6 kcal/mol, and a free energy for conformational change of the carrier (U) of 10.9 +/- 8.0 kcal/mol. In short-term cultured hepatocytes, Km increased in the absence of Na+ from 171 +/- 48 to 301 +/- 71 nmol/L, and Vmax of [3H]oleate decreased from 1063 +/- 69 to 847 +/- 68 pmol/min per milligram protein. The fitting of these data to a functional relation revealed a transmembrane potential-dependent component of parameters E and U to be -0.479 and -0.374 kcal/mol, respectively. It is proposed that for fatty acid influx a protonated fatty acid form is preferred that consists of a Na+ complex with the mesomeric form of nondissociated fatty acid from which Na+ and H+ are released during collision with the carrier.

Animals

Mechanical ventricular support using pulsatile Abiomed BVS 5000 and centrifugal Biomedicus-pump in postcardiotomy shock.

Since we started using ventricular assist devices (VAD) in July 1987 up to August 1993, 63 of 15,650 (0.4%) patients (pts) who underwent open heart surgery were supported postoperatively by VAD at out institution. Forty-three were male and 20 female, mean age 55.5 years. In 49 pts coronary artery bypass grafting (CABG), in 8 pts valve surgery, in 3 pts combined CABG and valve surgery and in 3 pts corrective procedures for congenital heart disease were performed. Perioperative myocardial infarction was the most frequent indication (73%). In 37 of the 63 pts (58.7%) a centrifugal (Biomedicus pump (group A) was used and in 26 pts (41.3%) a pulsatile Abiomed BVS 5000 (group B). Fourteen of 37 pts (38%) in group A were weaned from the VAD and all of them were discharged. Twenty-three pts were unable to be weaned and 19 of these pts died. The remaining 4 pts were transplanted successfully and subsequently 3 died and 1 was discharged. In all, 15 pts (39%) were long-term survivors. Sixteen of 26 pts (62%) in group B were weaned from VAD and 13 (50%) of them were discharged of whom 3 died. Ten patients were unable to be weaned and 7 of these died. The remaining 3 pts were transplanted successfully. In all, 16 pts (61.5%) were long-term survivors. The shorter the interval between beginning resuscitation and application of VAD the better the outcome. Younger age, VAD installation in OR, support time between 2 and 7 days and Abiomed pump, influence the survival rate positively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

[New avenues in therapy of postoperative low output syndrome].

The present definitions of low-output syndrome (LOS) associated with cardiac surgery are based on data obtained via the Swan-Ganz-catheter. However, further important data such as signs of chronic renal insufficiency, arterial vascular disease, and perioperative volume overload have hardly been considered. At the Heart Center NRW, FRG, the Swan-Ganz-Catheter is not used routinely to monitor patients following cardiac surgery. According to our experience, the definition of low-output syndrome includes a wider spectrum of relevant criteria. In addition to the data obtained by means of a central venous catheter the clinical aspect of the patient as well as laboratory analysis should be regarded as well. In 1259 consecutive patients (pts) (914 with coronary surgery and 318 with valve surgery) the incidence and mortality of low-output syndrome were determined. In 49 of the 941 coronary surgery pts (5.2%) a postoperative low-output syndrome occurred. Nine pts (0.95%) died as a result of this complication. According to our therapeutical strategy, the low-output syndrome was treated medically in 28 pts (2.9%); in 14 pts (1.5%) IABP implantation was necessary, and 7 pts needed mechanical circulatory support. Surprisingly, the same incidence of LOS occurred in the valve surgery group of pts as in the coronary group. We saw a low-output syndrome in 17 of the 318 pts (5.3%), with fatal outcome in three pts. In 14 of these pts (4.4%) the LOS was treated medically, while the remaining three pts (0.9%) required diastolic augmentation of the IABP.

Adult

Traumatic sinus of Valsalva fistula and aortic valve rupture.

A rare case of nonpenetrating trauma-induced fistula from the right sinus of Valsalva to the right atrium and aortic cusp disruption is reported. The trauma occurred 2 1/2 years previously. The fistula was closed with a Dacron patch, and the cusp tear was sutured.

Accidents, Traffic

Stentless xenograft valve in a truncus arteriosus communis.

We report the use of a recently developed stentless porcine valve in a 2-year-old child with truncus arteriosus communis (type I). The child had received no previous surgical palliation. Despite a markedly increased pulmonary arteriolar resistance the right ventricle was connected to the pulmonary artery with a homograft. The postoperative course was complicated at first by right ventricular failure due to pulmonary hypertension and secondarily by left ventricular failure caused by rapidly increasing truncal valve incompetence. Because we did not have a suitable homograft at hand we replaced the truncal valve with a stentless porcine xenograft valve.

Bioprosthesis

Delayed brachial plexus paralysis due to subclavian pseudoaneurysm after clavicular fracture.

Injuries to the brachial plexus and subclavian artery are serious complications of shoulder girdle trauma. Due to the close anatomical relationship between the brachial plexus and the subclavian artery in the thoracic outlet, both structures are often simultaneously involved in shoulder girdle injuries. Isolated lesions of the subclavian artery or the brachial plexus can also occur, especially with clavicular fractures. When a false subclavian aneurysm leads to a gradually increasing compression of the brachial plexus, the neurological signs and symptoms develop insidiously after the traumatic event.

Adult

Long term follow-up of Mitroflow pericardial valve prostheses in the small aortic annulus.

Between January 1985 and April 1992 we implanted 477 Mitroflow pericardial bioprostheses in 476 patients in our clinic. All except one valve prostheses were implanted in the aortic position. There were 160 male and 316 female patients, with a mean age of 74.1 years (range 30-89 years). Combined cardiac procedures were performed concomitantly with aortic valve replacement in 45 patients (9.5%): coronary artery revascularisation (n = 38), endarterectomy of the internal carotid artery (n = 4) and multiple valve replacement (n = 3). The sizes of the implanted Mitroflow prostheses were 100% in 19 mm, 70% in 21 mm, 60% in 23 mm and 8% in more than 25 mm. The hospital mortality was 1.3% (n = 5). During the mean follow-up period of 47.6 months valve failure requiring reoperation occurred in 7 patients (1.2%). The actuarial freedom from tissue failure is 89.9 +/- 2.5% and the actuarial survival rate is 90.3 +/- 1.7% (27 deaths) at 7 years. These findings corroborate our policy to continue to implant a pericardial prosthesis in the aortic position, especially in elderly patients with a smaller aortic annulus.

Adult

Tricuspid valve regurgitation following blunt thoracic trauma.

Valvular lesions following blunt thoracic trauma are uncommon. Tricuspid valve regurgitation occurs very rarely. We report a successful tricuspid valve reconstruction for rupture of the chordae tendineae in a young man nine years after a motor vehicle accident. The value of echocardiography and transesophageal echocardiography for the diagnosis and quantification of this valve lesion is stressed.

Accidents, Traffic

Role of the carotid sinus in response of integrated venous system to pulsatile and nonpulsatile perfusion.

Effects of pulsatile and nonpulsatile perfusion on capacity system were investigated in 33 open-chest mongrel dogs with extracorporeal circulation. In 28 dogs with intact carotid sinus nerves, after changing from nonpulsatile to pulsatile systemic perfusion the mean arterial pressure decreased by 14 +/- 1.5 mm Hg, peripheral resistance by 423 +/- 15 dyne.cm-5.sec, and venous blood volume by 3.3 +/- 0.4 ml/kg. After changing from pulsatile perfusion to nonpulsatile systemic perfusion the mean arterial pressure increased by 15 +/- 2.2 mm Hg, the peripheral resistance by 431 +/- 15 dyne.cm-5.sec, and venous volume by 3.9 +/- 0.5 ml/kg. The same effects were observed in five dogs with bilateral isolated carotid pulsatile perfusion or nonpulsatile perfusion and systemic nonpulsatile perfusion. These effects were abolished after denervation of pressor receptors and pharmacologic blockade of alpha and beta receptors. It is proposed that with nonpulsatile perfusion carotid sinus-mediated vasoconstriction occurs in the downstream part of the capacitive system, where more pronounced wall musculature with increased number of adrenergic receptors is present. The throttle effect caused by this "resistance" part of venous circulation leads to increase of pressure in the upstream section of the capacitive system, compensates for the constrictive effect of the sympathetic tone, and leads finally to an increased volume of the capacity system. We conclude that venous response to different perfusion modalities is critically dependent on intact carotid sinus nerves and adrenergic receptors in the veins.

Animals

Aortic valve replacement in octogenarians.

In a consecutive series of 1109 patients undergoing aortic valve replacement (AVR) between January 1988 and December 1990, there were 48 patients (33 female, 15 male) over 80 years of age (mean age 83.5 years, median 82.9 years). Of those, 33 had aortic stenosis and 15 combined aortic valve disease, with additional coronary artery disease being present in 36. Isolated AVR was performed in 25 patients, and it was combined with coronary venous bypass grafting, with 1-4 (mean 1.8) peripheral anastomoses in 23. Two patients died within 30 days (early mortality 4.2%). Non-fatal complications included one hemiparesis, four transient cerebral disorders, two cases of pneumonia which led to ventilatory assistance, three rethoracotomies because of postoperative bleeding, 15 tachycardias and one transient AV block. Late results were obtained after a median follow up time of 22 months. There were eight late deaths (four cardiac related, four not related) and a low incidence of non-fatal complications (two episodes of gastrointestinal bleeding while on oral anticoagulation, one cerebral transient ischemic attack and one acute left ventricular failure). Nine patients are in NYHA Class I, 12 in Class I-II, 11 in Class II, three in Class II-III and three in Class III. Of the surviving 38 patients, four are currently living in a home for the aged or a nursing home, while all the others are living in their own homes and are able to sustain a relatively independent life-style. We conclude that in very old patients with aortic valve disease, AVR can be performed with low mortality and few non-fatal complications.

Aged