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Biomedical subjects

Ewald Hennig

Publications and source records attributed to Ewald Hennig.

9 recordsLinked to original sources
PubMed2006

Improvement in survival after mechanical circulatory support with pneumatic pulsatile ventricular assist devices in pediatric patients.

BACKGROUND: Pediatric size pneumatically driven extracorporeal ventricular assist devices (VAD) for infants and small children were introduced into clinical routine in 1992. In the initial period, the results in infants were poor. Since then, several improvements have been introduced with regard to the cannulas, connectors, heparin coating of the blood pump inner surface, anticoagulant treatment and coagulation monitoring, and earlier decision-making in favor of pump implantation before irreversible shock has set in. METHODS: Since 1990 and as of January 1, 2005, 62 Berlin Heart Excor systems have been implanted in patients below 18 years of age at our institution. The patients were divided into two groups according to the period of treatment: period 1, devices implanted between 1990 and 1998 (n = 34), and period 2, devices implanted between 1999 and 2004 (n = 28). We compared our experience during the earlier and later periods. RESULTS: There were no significant differences in the preoperative patient data between the two periods except for time of support (17.9 +/- 27.7 days versus 53.2 +/- 83.9 days, p = 0.001). In period 1, more patients needed a biventricular VAD whereas in period 2, more patients were effectively treated with a left VAD (p = 0.05). In the later period, the chest could be primarily closed in a significantly higher percentage of infants (0% versus 89%, p = 0.012), and more infants could be extubated on the VAD (0% versus 55%, p = 0.16). Discharge from the hospital after either weaning from the system or heart transplantation was achieved for 35% in period 1 and for 68% in period 2 (p = 0.029). Whereas in period 1 there were no survivors in the group of children younger than 1 year old, during period 2, survival in this age group was similar to that of the two groups of older children (p = 0.024). There was a significant improvement in the discharge rate in period 2 in patients with cardiomyopathy (43% versus 76%, p = 0.045) and postcardiotomy heart failure (0% versus 57%, p = 0.01). CONCLUSIONS: Earlier implantation of VADs, heparin coating of the blood pumps, and substantial modifications in cannula design, anticoagulation, and the coagulation monitoring regimen have led to a significant increase in the survival and discharge rate, especially among children under 1 year of age. The pediatric size Berlin Heart Excor VAD is a valuable option as a bridge to heart transplantation or recovery for children suffering from cardiogenic shock.

Adolescent↗
PubMed2006

Mechanical cardiac support in the young with the Berlin Heart EXCOR pulsatile ventricular assist device: 15 years' experience.

The pediatric-size pneumatically driven pulsatile extracorporeal ventricular assist device (VAD) Berlin Heart EXCOR (Berlin Heart Mediprodukt GmbH, Berlin, Germany) was introduced into clinical practice by the German Heart Institute Berlin in 1992. Until July 1, 2005, Berlin Heart EXCOR systems have been used for circulatory support in 68 children up to 18 years of age with severe circulatory failure resistant to pharmacologic therapy. These were patients suffering from cardiomyopathy, fulminant myocarditis, end-stage congenital cardiac defects, and acute heart failure following congenital heart surgery. Mean VAD support time was 35 days (range, 0 to 420 days). Forty-two patients (62%) survived to transplantation or after weaning; 37 patients (54%), including eight infants, were discharged home. These results in patients with very advanced disease have improved significantly in recent years because of technical developments and growing experience in the treatment of patients on the device, in postoperative care and optimal timing for VAD implantation. Timely implantation of the Berlin Heart EXCOR in the course of progressive heart failure now appears to be justified because the system has undergone the necessary modifications and the accumulation of clinical knowledge has made its use highly reliable and safe.

Adolescent↗
PubMed2004

Permanent mechanical circulatory support in patients of advanced age.

OBJECTIVE: This study details our initial results of long-term left ventricular assist device (LVAD) support in patients suffering from catecholamine-dependent end-stage heart failure or cardiogenic shock with age above 65 years or age above 60 and contraindications to cardiac transplantation. METHODS: Between September 2000 and July 2002, 27 patients received implantation of left ventricular assist devices (Micromed DeBakey (n=15), Berlin Heart Excor (n=6), Arrow Lion Heart (n=4) and Novacor N100 (n=2)). The mean age of this group was 66.2+/-4.1 (60-77) years. The patients presented with the following features by the time of LVAD implantation: failure of weaning from inotropic support (78%), either profound cardiogenic shock (37%) or instable hemodynamic status (22%), high-dose inotropic (52%) or intraaortic balloon pump support (11%), dialysis (15%), artificial ventilation (15%), and at least one previous cardiac procedure (44%). RESULTS: The cumulative survival rate for the whole group was 63% at 30 days, 30% at 180 days, and 22% at 2 years. The presence of preoperative cardiogenic shock was associated with a higher perioperative mortality rate. Late complications (n=7) included replacement of two thrombosed DeBakey LVADs and five late deaths secondary to thrombembolism/intracranial hemorrhage (DeBakey LVAD, n=3) or septicemia (n=2). As of May 15, 2003, six patients remain on LVAD support for an average of 653 (339-953) days, three patients now for more than 2 years. Ten patients were discharged home to spend 73% of their life span on out-of-hospital long-term LVAD support. CONCLUSION: This study reports the first single-center experience of permanent LVAD support in patients of advanced age. For this initial experience, many patients with critical circulatory status and previous cardiac operations were included and a high postoperative mortality rate was encountered among them. Older age and associated multimorbidity are the key determinants rendering the conditions of LVAD therapy for this patient cohort to be different from the bridge-to-transplant experience. The LVADs employed in this study showed different capabilities with regard to long-term support. Our experience shows that permanent mechanical circulatory support does have the potential to evolve as a treatment option in selected elderly patients with end-stage heart failure.

Aged↗
PubMed2004

First experiences with a novel magnetically suspended axial flow left ventricular assist device.

UNLABELLED: Axial flow pumps have gained increased acceptance since their first clinical use in 1998. The present report summarizes the clinical experience with patients treated for severe cardiogenic shock for the first time with a newly developed axial flow pump with magnetically levitated bearings. MATERIAL AND METHODS: The axial flow pump Incor was implanted in 24 patients between June 2002 and June 2003. All except one patient were men. In 16 patients dilative cardiomyopathy, in seven ischemic and in one restrictive cardiomypathy had been diagnosed. All patients presented with catecholamine-dependent end-stage heart failure, seven of them were on an artificial ventilator and three were dependent on intraaortic balloon pump support. All patients suffered from organ dysfunction resulting from low cardiac output. RESULTS: There were no perioperative deaths. The 30-day mortality rate was 8% (n = 2); 79% ( n = 19) of patients reached a condition to be discharged home. The cumulative time on the device is 6.9 years; the longest individual time up to July 1, 2003 is 12.6 months. There were no structural defects or failures of the system. In one case the controller had to be exchanged because of intermittent malfunction. Cardiac output ranged between 4 and 6 l in all instances and there were no cases of infection of the drive-line or the system. Hemolysis was present initially but was not detectable in the later course. There were three instances of transient ischemic attacks. Two patients developed late cardiac tamponade with re-opening of the chest after 9 and 14 days. In one patient persistent gastrointestinal bleeding required re-hospitalization and transfusion therapy. Two patients were weaned from the device after 6 and 7 months of support, respectively. CONCLUSION: The preliminary clinical experience with Incor is promising. The flow is sufficient for recovery from multiorgan failure and the pump allows long-term hemolysis-free support. The concept of magnetically levitated bearings has proven to be durable and reliable. In the case that the heart may recover through unloading, weaning from the pump is possible.

Adult↗
PubMed2003

Heart transplantation in children after mechanical circulatory support with pulsatile pneumatic assist device.

BACKGROUND: Mechanical support with a pulsatile pneumatic ventricular assist device (VAD) is a complex rescue procedure performed in children with untreatable cardiogenic shock. Its impact on early and long-term survival after subsequent heart transplantation (HTx) remains to be determined. METHODS: We reviewed retrospectively the course of 95 children (median age, 8 years; range, 8 days-17 years; body weight, 24 kg; range, 3-110 kg) who underwent HTx. Group A, the elective-HTx group, consists of 33 children who were treated as outpatients before transplantation. Group B, the emergency-HTx group, has 44 children who were critically ill and hospitalized before transplantation but without ventricular assist devices, whereas Group C, the VAD-HTx group, consists of 18 children resuscitated and supported with pulsatile pneumatic VADs for a median time of 20 days. RESULTS: Overall actuarial survival after cardiac transplantation was 86% at 1 month, 82% at 1 year, and 78% at 5 years, without significant differences among the 3 sub-groups. Group A had the best long-term survival rate, 88% at 1 month, 88% at 1 year, and 80% at 5 years. Group B had a survival rate of 88% at 1 month, 82% at 1 year, and 79% at 5 years. Group C had a survival rate of 72% at 1 month, 72% at 1 year, and 72% at 5 years. We found no differences in neurologic outcome, acute cardiac rejection, or transplant failure. The survival rate was significantly better in the children with cardiomyopathy compared with those with congenital heart defects (p = 0.014). CONCLUSIONS: Bridging to HTx with a pulsatile pneumatic VAD is a safe procedure in pediatric patients. After HTx, overall survival of these children is similar to that of patients who were bridged with inotropes or who were awaiting heart transplantation electively.

Actuarial Analysis↗
PubMed2003

Reduction of microemboli count in the priming fluid of cardiopulmonary bypass circuits.

Microemboli may impair cognitive function in patients undergoing heart surgery. Prebypass filtration has been shown to reduce particle load in the cardiopulmonary bypass (CPB) priming fluid. This study was performed to detect the embolic load of CPB priming fluid, to determine the efficacy of a 0.2 microm prebypass filter (PBF) in reducing emboli in the range of 0.1-5 microm and to provide guidelines for the handling of the device. A total of 12 CPB circuits were tested in two groups, using a laser light scattering particle counter, sensitive to microemboli in the range of 0.1-5 microm. In control group A, priming fluid before administration to the CPB circuit was analyzed. Group B circuits contained microporous membrane oxygenators (N = 5); group C consisted of CPB circuits with excluded membrane oxygenators (N = 7). When group A was compared to groups B and C, significantly more microemboli were found in the categories 0.2 microm, 0.5 microm, 0.8 microm for both groups B and C (p < .05). Group C circuits had higher microemboli counts in the categories 1.5 microm and 3 microm (p < .05) when compared to group B. Microemboli bigger than 0.2 microm could be eliminated after 2 min of prebypass filtration with a CPB flow of 5 L/min. The number of microemboli smaller than 0.2 microm was reduced substantially. Small microemboli with a size of 0.1 microm originate mainly from the priming solution. Microemboli in the range of 0.2 microm, 0.5 microm, and 0.8 microm originate mainly from the CBP circuit. In circuits with bypassed membrane oxygenators, a higher microemboli count in the range of 1.5 microm and 3 microm may be explained by a possible filtering capacity of membrane oxygenators. The 0.2 microm PBF is an effective tool to reduce the particle load in the CPB priming fluid.

Cardiac Surgical Procedures↗
PubMed2003

The MicroMed DeBakey VAD--part I: The pump and the blood flow.

The results obtained in over 100 patients implanted with the MicroMed DeBakey VAD in several centers in Europe and USA (September 2001, M. Loebe, personal communication) demonstrate that the effectiveness of the MicroMed DeBakey VAD is comparable to that of the pulsatile devices and that it also shows some superior properties. Recently, other axial pumps--the Jarvic 2000 (72) and HeartMate II (73)--have come into clinical use. Because the patients show good tolerance of the nonpulsatile blood flow in the early postoperative period, and pulsatility increased with recovery of the left ventricle because of unloading, we believe that the axial pumps will gain wide acceptance and provide a new option in the treatment of heart failure.

Heart-Assist Devices↗
PubMed2002

[Heart assist systems--current status].

BACKGROUND: Heart failure is the leading cause of death in the developed countries. Organ-preserving operative procedures on the failing heart like coronary artery bypass procedures or resection of left ventricular aneurysms are part of the routine care in cardiac surgery today. Terminal heart failure refractory to optimized drug therapy, however, will require a heart transplantation or the implantation of artificial blood pumps. While heart transplantation has proven to provide excellent long-term results with 10-year survival rates at 50%, it will remain a casuistic therapy, limited by the comparatively small number of procedures which can be performed. ARTIFICIAL BLOOD PUMPS: The current status of development of artificial blood pumps is represented by the broad availability of partially-implantable electric motor-driven left ventricular assist devices (LVAD), which still require a percutaneous cable for energy supply and device control from external sources while the blood pump itself resides inside the body. The recently introduced axial-flow devices (DeBakey, Jarvik 2000 and HeartMate II LVADs) deliver a continuous blood flow and obviously provide distinct advantages with regard to a reduction in size, weight and energy demands, simplified implantation technique and device control when compared to the previously available partially-implantable electric motor-driven pulsatile blood pumps (Novacor N100, TCl Heart Mate LVADs). The first systems designed for long-term or permanent use (Lion Heart LVAD, AbioCor replacement heart) are completely implantable devices featuring percutaneous energy transmission and device control. However, the latter are more complex devices and their clinical application is still limited to a small number of cases, which precludes a judgment about their potential at this time. INDICATIONS: The use of paracorporeal pneumatically accentuated blood pump systems is still indicated in cases of most severe biventricular heart failure and multiorgan failure or if only short- to mid-term circulatory support is anticipated. Well established indications for utilization of artificial blood pumps are the bridge-to-transplant procedure, which yields results comparable to primary heart transplantation, and acute cardiac failure following myocardial infarction or cardiac surgical procedures. In newborns and children, encouraging results were obtained when miniaturized blood pumps of the Berlin Heart System were utilized for heart failure in myocarditis or dilative cardiomyopathy. With advanced reliability of artificial blood pumps and in face of the high incidence of heart failure, especially in the older age group, the long-term application of artificial bloods pump appears to be justified.

Equipment Design↗