Biomedical subjects

Robert L Kormos

Publications and source records attributed to Robert L Kormos.

26 records · Page 2Linked to original sources

PubMed2003

Mechanical Circulatory Support device database of the International Society for Heart and Lung Transplantation: first annual report--2003.

Over the last 2 decades, mechanical circulatory support devices have been developed with the goal of supporting patients with advanced heart failure as a bridge to cardiac transplantation, a bridge to recovery, and an alternative to transplantation (also called chronic or destination therapy). The current generation of devices provides a differentiated spectrum of circulatory support. The major limitations of mechanical circulatory support devices are infection, coagulopathies and device dysfunction. The Scientific Council on Mechanical Circulatory Support of the International Society for Heart and Lung Transplantation has established an international database to generate critical data to advance knowledge about the effectiveness of mechanical circulatory support device therapy for one of the most difficult and costly contemporary medical problems, the malignant syndrome of advanced heart failure.

Adolescent↗

PubMed2003

In vivo evaluation of a MPC polymer coated continuous flow left ventricular assist system.

The aim of this study was the evaluation of the thrombogenicity and the biocompatibility of the SunMedical EVAHEART left ventricular assist system (LVAS) coated with 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer compared to a diamond-like carbon (DLC) coating. Four calves were implanted with the MPC polymer-coated LVAS. Eight calves were implanted with DLC coated LVAS. The thrombogenicity and biocompatibility of the pumps were evaluated. At explant, 60.0 +/- 37.2% (5-85%) of the pump surface area was still coated with MPC polymer after the duration of 45.0 +/- 32.0 days. In 1 out of 4 MPC and 2 out of 8 DLC coated pumps, there was a very small amount of thrombus around the seal ring; otherwise the blood contacting surfaces were free of thrombus. Major organs were normal except for a few lesions in kidneys from both groups. The MPC polymer coated EVAHEART LVAS seems to have low thrombogenicity and high biocompatibility similar to the DLC coated system. The current study demonstrated that the MPC polymer coating shows great promise for being used as an antithrombogenic substrate for the LVAS due to its ease of application, significant cost benefit, and reduction in anticoagulation therapy in acute postoperative period.

Animals↗

PubMed2003

Minimal evidence of transdifferentiation from recipient bone marrow to parenchymal cells in regenerating and long-surviving human allografts.

Liver, small intestine, and heart allografts in residence for 4 days to 16 years were analyzed by simultaneous XY fluorescent in situ hybridization to search for evidence of the recently described process of transdifferentiation of recipient bone marrow stem cells to allograft parenchymal cells. These studies were carried out in an effort to find conditions associated with maximal levels of engraftment or expansion of the recipient parenchymal cells. Despite prolonged survival up to 16 years, regeneration after severe preservation injury or use of split livers, only rare, isolated and tentatively identified recipient hepatocytes were detected in liver allografts. In intestinal allografts, despite survival of up to 8 years and extensive mucosal regeneration because of severe damage from acute rejection, there was no crypt replacement by recipient epithelial cells. In cardiac allografts, no recipient myocytes were detected despite recipient survival for 2-3 days and 3-4 weeks after myocardial infarcts at 5 and 8 years after transplantation. Parenchymal cell transdifferentiation from recipient bone marrow stem cells was rare to nonexistent in severely injured, regenerating, and long-surviving allografts. The rare isolated recipient parenchymal cells tentatively identified did not appear to behave as stem cells: they did not form clusters and did not increase with time after transplantation. Because of the extremely low frequency, interpretation was difficult. Regardless of these results, a more vigorous search for conditions that promote transdifferentiation is warranted.

Adolescent↗

PubMed2003

Avoidant coping with health problems is related to poorer quality of life among lung transplant candidates.

CONTEXT: Lung transplant candidates face numerous health-related stressors. Although previous work has described the range of coping strategies candidates may use, whether those strategies are related to quality of life in physical functioning, emotional, and social domains has rarely been examined. METHODS: Adult lung transplant candidates (N = 128) participated in semistructured interviews that included questions regarding global and domain-specific quality of life and a multidimensional assessment of coping with health-related problems. Demographic characteristics, health status, and other psychosocial variables were also assessed, and their effects were examined and controlled in multivariate analyses of the coping-quality-of-life relationship. RESULTS: Respondents were most likely to use active, acceptance, and support-seeking strategies to cope with health problems. Self-blame or avoidance were rarely used. Although used least often, avoidant coping was the most strongly and consistently related to quality of life. With demographic and psychosocial variables controlled, higher avoidant coping remained associated with significantly poorer global quality of life, bodily pain, difficulty with daily work or activities as a function of emotional problems, and depressive symptomatology. Avoidant coping accentuated the association of poor health status and lower quality of life. Among respondents with lower health status, using more avoidant coping was associated with greater difficulty functioning in daily activities as a result of emotional problems. Those with higher health status had less difficulty functioning in daily activities as a result of emotional problems. CONCLUSIONS: Transplant team members are encouraged to be aware of and help patients refrain from using avoidant coping strategies.

Activities of Daily Living↗

PubMed2002

EVAHEART: an implantable centrifugal blood pump for long-term circulatory support.

OBJECTIVE: We developed "EVAHEART": a compact centrifugal blood pump system as an implantable left ventricular assist device for long-term circulatory support. The 55 x 64 mm pump is made from pure titanium, and weighs 370 g. The entire blood-contacting surface is covered with an anti-thrombogenic coating of diamond like carbon (DLC) or 2-methacryloyloxyethyl phosphorylcholine (MPC) to improve blood compatibility. Flows exceeding 12 L/min against 100 mmHg pressure at 2600 rpm was measured. A low-temperature mechanical seal with recirculating cooling system is used to seal the shaft. EVAHEART demonstrated an acceptably low hemolysis rate with normalized index of hemolysis of 0.005 +/- 0.002 g/100L. METHODS: We evaluated the pump in long-term in-vivo experiments with seven calves. Via left thoracotomy, we conducted left ventricular apex-descending aorta bypass, placing the pump in the left thoracic cavity. RESULTS: Pump flow rates was maintained at 5-9 L/min, pump power consumption remained stable at 9-10 W in all cases, plasma free Hb levels were less than 15 mg/dl, and the seal system showed good seal capability throughout the experiments. The calves were sacrificed on schedule on postoperative day 200, 222, 142, 90, 151, 155, and 133. No thrombi formed on the blood contacting surface with either the DLC or MPC coating, and no major organ thromboembolisms occurred except for a few small renal infarcts. CONCLUSION: EVAHEART centrifugal blood pump demonstrated excellent performance in long-term in-vivo experiments.

Animals↗

PubMed2002

Long-term follow-up of Thoratec ventricular assist device bridge-to-recovery patients successfully removed from support after recovery of ventricular function.

BACKGROUND: In certain forms of severe heart failure there is sufficient improvement in cardiac function during ventricular assist device (VAD) support to allow removal of the device. However, it is critical to know whether there is sustained recovery of the heart and long-term patient survival if VAD bridging to recovery is to be considered over the option of transplantation. METHODS: To determine long-term outcome of survivors of VAD bridge-to-recovery procedures, we retrospectively evaluated 22 patients with non-ischemic heart failure successfully weaned from the Thoratec left ventricular assist device (LVAD) or biventricular assist device (BVAD) after recovery of ventricular function at 14 medical centers. All patients were in imminent risk of dying and were selected for VAD support using standard bridge-to-transplant requirements. There were 12 females and 10 males with an average age of 32 (range, 12-49). The etiologies were 12 with myocarditis, 7 with cardiomyopathies (4 post-partum [PPCM], 1 viral [VCM], and 2 idiopathic [IDCM]), and 3 with a combination of myocarditis and cardiomyopathy. BVADs were used in 13 patients and isolated LVADs in 9 patients, for an average duration of 57 days (range, 11-190 days), before return of ventricular function and successful weaning from the device. Post-VAD survival was compared with 43 VAD bridge-to-transplant patients with the same etiologies who underwent cardiac transplantation instead of device weaning. RESULTS: Nineteen of the 22 patients are currently alive. Three patients required heart transplantation, 1 within 1 day, 2 at 12 and 13 months post-weaning, and 2 died at 2.5 and 6 months. The remaining 17 patients are alive with their native hearts after an average of 3.2 years (range, 1.2-10 years). The actuarial survival of native hearts (transplant-free survival) post-VAD support is 86% at 1 year and 77% at 5 years, which was not significantly different (p = 0.94) from that of post-VAD transplanted patients, also at 86% and 77%, respectively. CONCLUSIONS: Long-term survival for bridge-to-recovery with VADs for acute cardiomyopathies and myocarditis is equivalent to that for cardiac transplantation. Recovery of the native heart, which can take weeks to months of VAD support, is the most desirable clinical outcome and should be actively sought, with transplantation used only after recovery of ventricular function has been ruled out.

Adolescent↗

PubMedDate not supplied

Personality characteristics among cardiothoracic transplant recipients.

Personality characteristics are clinically believed to predict posttransplant adherence and outcome; however, data, as to the prevalence and type of personality disorders (PDs) and distribution of personality traits among transplant (txp) populations, are sparse and inconclusive. This paper reports on the prevalence and type of PD and range of personality traits, according to the Five-Factor model, among 73 adult cardiothoracic txp recipients. It represents the first systematic assessment of PDs and traits in a sample of txp recipients. Personality disorders were assessed with a semistructured diagnostic interview; personality traits were assessed with a self-report instrument. Thirty-three percent of the sample met diagnostic criteria for a PD, approximately three times higher than prevalence of PD previously reported among nonpsychiatric populations. Mean values of personality traits for the sample were in the normative range but with wide variability; extreme values on four of the five traits were scored by subjects with a PD. This unexpectedly high prevalence of PD and the wide variability in traits among heart and lung recipients alert clinicians to consider personality characteristics when planning interventions to increase compliance and maximize quality of life after cardiothoracic transplantation.

Adult↗

PubMedDate not supplied

Pulsatile paracorporeal assist devices in children and adolescents with biventricular failure.

Children with heart failure unresponsive to medical therapy are left with few options for survival. Pulsatile paracorporeal ventricular assist devices are life-saving options for such patients, allowing for bridge to transplantation or cardiac recovery. From March 1997 to July 2004, 12 patients underwent implantation of Thoratec biventricular assist devices (BVADs) for refractory heart failure. Mean age was 14.9 (range 7-20) and mean BSA was 1.7 (range 1.1-1.9). Indications for support included end-stage cardiomyopathy (n=10), myocarditis (n=1), and postcardiotomy heart failure (n=1). Preimplant variables included 50% of patients requiring mechanical ventilation (mean 4.2 days), hyperbilirubinemia in 58%, and acute renal failure in 50%. Mean duration of support was 64.5 (range 2-175) days. Overall survival was 83%, with nine patients successfully bridged to transplantation (75%). One patient exhibited recovery allowing for device explantation, and two patients died while on BVADs. Complications included bleeding requiring reoperation in 25% (n=3), stroke in 8% (n=1), driveline infections in 17% (n=2), and device malfunction in one patient. Pulsatile paracorporeal BVADs can be used successfully in children and adolescents with heart failure. These results warrant consideration of using available miniaturized technology in the United States for the support of smaller children with intractable biventricular failure.

Acute Kidney Injury↗