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Biomedical subjects

Friedhelm Beyersdorf

Publications and source records attributed to Friedhelm Beyersdorf.

At least 19 recordsLinked to original sources
PubMed2006

Sudden cardiac death: directing the scope of resuscitation towards the heart and brain.

BACKGROUND: The fundamental goal of cardiopulmonary resuscitation (CPR) is recovery of the heart and the brain. This is best achieved by (1) immediate CPR for coronary and cerebral perfusion, (2) correction of the cause of cardiac arrest, and (3) controlled cardioplegic cardiac reperfusion. Failure of such an integrated therapy may cause permanent brain damage despite cardiac resuscitation. METHODS: This strategy was applied at four centers to 34 sudden cardiac death patients (a) after acute myocardial infarction (n = 20), (b) "intraoperatively" following successful discontinuation of cardiopulmonary bypass (n = 4), and (c) "postoperatively" in the surgical ICU (n = 10). In each witnessed arrest the patient failed to respond to conventional CPR with ACLS interventions, including defibrillation. The cardiac arrest interval was 72 +/- 43 min (20-150 min). Compression and drugs maintained a BP > 60 mmHg to avoid cerebral hypoperfusion. Operating room (OR) transfer was delayed until the blood pressure was monitored. In four patients femoral bypass maintained perfusion while an angiographic diagnosis was made. RESULTS: Management principles included no repeat defibrillation attempts after 10 min of unsuccessful CPR, catheter-monitored peak BP > 60 mmHg during diagnosis and transit to the operating room, left ventricular venting during cardiopulmonary bypass and 20 min global and graft substrate enriched blood cardioplegic reperfusion. Survival was 79.4% with two neurological complications (5.8%). CONCLUSIONS: Recovery without adverse neurological outcomes is possible in a large number of cardiac arrest victims following prolonged manual CPR. Therapy is directed toward maintaining a monitored peak BP above 60 mmHg, determining the nature of the cardiac cause, and correcting it with controlled reperfusion to preserve function.

Cardioplegic Solutions↗
PubMed2006

Improvement of contractility accompanies angiogenesis rather than arteriogenesis in chronic myocardial ischemia.

INTRODUCTION: Growth factor therapy provides a therapeutic alternative for "no option" patients with coronary disease. Fibroblast Growth Factor-2 (FGF-2) predominantly stimulates angiogenesis, the growth of new capillaries, whereas Monocyte Chemoattractant Protein-1 (MCP-1) is considered an arteriogenic agent. We hypothesised a synergetic effect of FGF-2 and MCP-1 in ischemic myocardium. METHODS: A severe coronary stenosis was created in pigs. After one week, chronic ischemia was confirmed by angiography, echocardiography, reduced ejection fraction, and increase of marker enzymes. FGF-2, MCP-1, both, or vector only were then injected intramyocardially as plasmid DNA in the impaired area. Regional contractility and number of capillaries and arterial vessels were evaluated after three months. RESULTS: FGF-2, FGF-2+MCP-1, and vector, but not MCP-1 alone improved regional contractility at rest, whereas only FGF-2 alone ameliorated function under stress conditions. Angiogenesis in the ischemic area was stimulated by FGF-2 compared to MCP-1. In contrast, MCP-1 induced arteriogenesis relative to FGF-2. CONCLUSION: Differences for vessel growth and regional function were apparent between FGF-2 and MCP-1. This contrast could allow the speculation that development of a flow reserve in chronically ischemic myocardium is linked to angiogenesis rather than to arteriogenesis. No additional benefits were seen following combined therapy.

Animals↗
PubMed2006

Aortic atresia with aortico-left ventricular tunnel mimicking severe aortic incompetence in utero.

A fetus was diagnosed with regurgitation from the aorta into the left ventricle. A large aortico-left ventricular tunnel with aortic atresia was identified postnatally by echocardiography in a neonate suffering from severe heart failure. We successfully reconstructed the valve and closed the tunnel with a patch on his first day of life. At three-month follow-up, the baby is asymptomatic with mild aortic regurgitation. The combination of congenital aortico-left ventricular tunnel and aortic atresia can be misinterpreted in prenatal echocardiography as aortic regurgitation. This pathology may require urgent operative interventions.

Aortic Valve↗
PubMed2006

Neurophysiological monitoring during thoracoabdominal aortic endovascular stent graft implantation.

OBJECTIVE: The aim of this study was to evaluate the benefit of neurophysiological monitoring during thoracic and thoracoabdominal endovascular stent graft implantation. METHODS: The spinal cords of 21 patients undergoing endovascular stent graft implantation on the thoracic and thoracoabdominal aorta were monitored with transcranial motor-evoked potentials (tcMEP) and somatosensory-evoked potentials (SSEP). All patients underwent mild systemic hypothermia (34-35 degrees C), constant cerebrospinal fluid (CSF) pressure and vital parameter monitoring. If CSF pressure exceeded 15 mmHg, CSF-drainage was carried out. RESULTS: Three of the 21 patients (14%) exhibited short-term loss of tcMEP and SSEP after the deployment of the self-expanding endoprosthesis. We observed an intraoperative recovery of the evoked potentials in all cases. CSF-drainage was necessary in three of them. One patient, whose potentials were stable intraoperatively, developed paraparesis 3 weeks after the intervention. CONCLUSIONS: Neurophysiological monitoring has proved to be an ideal monitoring method to detect spinal cord ischemia during thoracic and thoracoabdominal endovascular stent graft implantation. Due to the advantages of endovascular therapy (no aortic cross-clamping, continuous distal perfusion, and no reperfusion injury), changes in potentials were seldom observed.

Aged↗
PubMed2006

Mechanical reliability of the Jarvik 2000 Heart.

BACKGROUND: Device failure is a limitation of permanent mechanical circulatory support. We studied the mechanical reliability of the Jarvik 2000 Heart, an axial flow pump with ceramic bearings designed to provide more than 10 years' durability. METHODS: The Jarvik 2000 Heart was implanted in 102 patients between April 2000 and December 2004. Eighty-three pumps with an abdominal driveline were implanted as a bridge-to-transplantation, and 19 with postauricular power supply as lifetime therapy. Eighteen pumps were recovered intact after clinical use and run continuously on the bench to further assess durability. RESULTS: No implantable component failure occurred either in patients or during bench testing. The cumulative pump run-time was 110 years: 59 years overall in vivo and 51 years in vitro. The mean support time for bridge-to-transplant recipients was 159 days, and for discharged lifetime-therapy recipients 551 days. Six recipients were supported moer than 2 years, with the longest ongoing approaching 5 years. External cables caused three system failures, with a 95% freedom from system failure at 4 years. Device malfunctions, related to external cables (9) and lack of a backup battery (1), caused no adverse consequences. Before introduction of noncorrosive, gold-plated stainless steel connectors, corrosion was observed on three connectors to the retroauricular power supply. CONCLUSIONS: The Jarvik 2000 Heart has had no implantable component failure. Meaningful durability data and failure mode can only be established by real-time testing in patients. The reliability and dependability of this device, in addition to the exchangeability of external components, give promise for long-term circulatory support in critically ill heart failure patients.

Equipment Failure Analysis↗
PubMed2006

Perioperative management to improve neurologic outcome in thoracic or thoracoabdominal aortic stent-grafting.

BACKGROUND: Thoracic or thoracoabdominal aortic stent-graft repair has shown a reduction in morbidity and mortality rates due to the procedure's advantages (no aortic cross-clamping, continuous distal aortic perfusion, no reperfusion injury). However, 3% to 12% of the patients are at risk of spinal cord ischemia. We investigated spinal cord protective measures with evoked potentials, cerebrospinal fluid drainage, and prevention of hypotension to minimize postoperative neurologic deficit. METHODS: Between November 2000 and July 2005, vital parameters and spinal cord function were monitored, including cerebrospinal fluid pressure and transcranial motor-evoked and somatosensory-evoked potentials in 36 stent-graft procedures (31 patients) on the thoracic or thoracoabdominal aorta. RESULTS: Stent-graft placement was technically successful in all patients. We achieved a survival rate of 100% without neurologic deficit after fast-track extubation. Eleven of 31 patients exhibited changes in evoked potentials during stent-graft deployment. In 12 of 31 patients (including the 11 with evoked potential alterations), cerebrospinal fluid pressure exceeded 15 mm Hg. Cerebrospinal fluid drainage and vital parameter adjustment were executed in those instances. We observed intraoperative evoked potential total recovery in 10 of 11 patients after these interventions. CONCLUSIONS: Interventions to improve spinal cord perfusion led to total recovery of spinal function in most patients (10/11). Therefore, spinal cord protective measures with motor- and somatosensory-evoked potential monitoring, cerebrospinal fluid drainage, and prevention of hypotension can reduce the incidence of spinal cord ischemia and improve the neurologic outcome of patients undergoing endovascular thoracic or thoracoabdominal aortic repair.

Adult↗
PubMed2006

Improved durability of the HeartMate XVE left ventricular assist device provides safe mechanical support up to 1 year but is associated with high risk of device failure in the second year.

BACKGROUND: Life-threatening device failure of the HeartMate VE due to biologic inflow valve incompetence or motor failure is a major drawback of long-term mechanical support when using this left ventricular assist device (LVAD). The new XVE model is the result of recent technical improvements. The aim of this study was to compare the clinical performance and durability of the new and earlier HeartMate versions. METHODS: We analyzed the incidence of device failure and of other device-specific complications (infections, bleeding) in 9 VE and 17 XVE patients. Explanted pumps were examined and biologic valve damage classified according to a score ranging from 0 (no visible damage) to 3 (severe destruction). RESULTS: Mean support time was 145 +/- 92 and 267 +/- 195 days in the VE and XVE groups, respectively (difference not significant [NS]). Survival was 89% (VE) vs 75% (XVE). The incidence of device failure requiring urgent heart transplantation or device replacement was 44% (VE) vs 31% (XVE) (NS). Device failure occurred significantly later in the XVE group (200 +/- 34 vs 487 +/- 53 days, p < 0.01). Causes of device failure were inflow valve incompetence (n = 6) and motor failure (n = 3). Acute device failure caused 1 death in the XVE group. One XVE patient has been on mechanical support for > 483 days. Macroscopic inflow valve damage score after explantation of the devices was 2.2 +/- 1.1 in the VE group and 2.0 +/- 0.8 in the XVE group (NS). CONCLUSIONS: The novel HeartMate XVE offers greater durability and provides reliable mechanical support in the first year. However, there is a high risk of life-threatening device failure in the second year. Further technical refinements are necessary to meet the challenges of safe long-term circulatory assistance.

Adolescent↗
PubMed2006

Myoblast-seeded biodegradable scaffolds to prevent post-myocardial infarction evolution toward heart failure.

OBJECTIVE(S): Even though the mechanism is not clearly understood, direct intramyocardial cell transplantation has demonstrated potential to treat patients with severe heart failure. We previously reported on the bioengineering of myoblast-based constructs. We investigate here the functional outcome of infarcted hearts treated by implantation of myoblast-seeded scaffolds. METHODS: Adult Lewis rats with echocardiography-confirmed postinfarction reduced ejection fraction (48.3% +/- 1.1%) were randomized to (1) implantation of myoblast-seeded polyurethane patches at the site of infarction (PU-MyoB, n = 11), (2) implantation of nonseeded polyurethane patches (PU, n = 11), (3) sham operation (Sham, n = 12), and (4) direct intramyocardial myoblast injection (MyoB, n = 11). Four weeks later, the functional assessment by echocardiography was repeated, and we additionally performed left ventricular catheterization plus histologic studies. RESULTS: The ejection fraction significantly decreased in the PU (39.1% +/- 2.3%; P = .02) and Sham (39.9% +/- 3.5%; P = .04) groups, whereas it remained stable in the PU-MyoB (48.4% +/- 3.1%) and MyoB (47.9% +/- 3.0%) groups during the observation time. Similarly, left ventricular contractility was significantly higher in groups PU-MyoB (4960 +/- 266 mm Hg/s) and MyoB (4748 +/- 304 mm Hg/s) than in groups PU (3909 +/- 248 mm Hg/s, P = .01) and Sham (4028 +/- 199 mm Hg/s, P = .01). Immunohistology identified a high density of myoblasts within the seeded scaffolds without any migration toward the host cardiac tissue and no evidence of cardiac cell differentiation. CONCLUSIONS: Myoblast-seeded polyurethane scaffolds prevent post-myocardial infarction progression toward heart failure as efficiently as direct intramyocardial injection. The immunohistologic analysis suggests that an indirect mechanism, potentially a paracrine effect, may be assumed.

Animals↗
PubMed2005

Advanced heart failure: feasibility study of long-term continuous axial flow pump support.

AIMS: A lack of donor hearts has stimulated interest in using blood pumps to treat severe heart failure. We tested the hypothesis that a new continuous flow circulatory assist device could be employed safely to relieve symptoms of heart failure and evaluated the potential to prolong life. METHODS AND RESULTS: An intracardiac axial flow pump was implanted in 17 heart failure patients [idiopathic dilated (12), ischaemic (4), or amyloid cardiomyopathy (1)]. All were deemed ineligible for transplantation. Implantation of the device was by left thoracotomy (15) or median sternotomy (2). Power delivery was by a skull-mounted titanium pedestal. All patients survived surgery. None needed right ventricular support. There were three hospital deaths, two early from subdural haematoma and aortic thrombosis, one late after switching to transplantation. A total of 14 patients left hospital with a cumulative support-time of 15.9 years (median: 293 days, interquartile range: 286 days, 1-44 months). Actuarial 1-, 2-, and 3-year survivals were 56, 47, and 24%, respectively. There was no pump failure. Quality of life scores improved. Two superficial pedestal infections were successfully treated. Four patients had cerebral thrombo-embolism: two early events attributed to inadequate anticoagulation and two late with near-complete resolution. An improved anticoagulant regime addressed this problem. Late death occurred in five patients from battery disconnection, subdural haematoma, bowel ischaemia, respiratory failure, and after cardiac transplantation. CONCLUSION: Continuous flow blood pumps provided symptomatic relief of severe heart failure with high quality of life. Event-free survival reached 4 years. Analysis of adverse events led to improved management strategies. There is potential for widespread use of blood pumps in the community. A controlled trial is required.

Aged↗
PubMed2005

Anterior approach to implant the Jarvik 2000 with retroauricular power supply.

The retroauricular power supply of the Jarvik 2000 (Jarvik Heart Inc, New York, NY) left ventricular assist device is suitable for permanent support, as it is associated with fewer infections than conventional drivelines. Implantation through a left-lateral thoracotomy limits the performance of additional cardiac procedures. We describe a technique that used a sternotomy for the implantation of the Jarvik 2000 with retroauricular power supply in two patients. The retroauricular power supply of the Jarvik 2000 can be provided with an anterior approach, allowing full surgical access to the heart. If the outflow graft to the ascending aorta indeed reduces aortic stasis and thromboembolic events, the anterior approach with retroauricular power delivery might evolve into a standard procedure.

Aged↗