Controller for an Axial Flow Blood Pump

A rotary blood pump inherently provides only one noninvasive "observable'" parameter (motor current) and allows for only one "controllable" parameter (pump speed). To maintain the systemic circulation properly, the pump speed must be controlled to sustain appropriate outlet Hows and perfusion pressure while preventing pulmonary damage caused by extremes in preload. Steady-state data were collected at repeated intervals during chronic trials of the Nimbus AxiPump (Nimbus, Inc., Rancho Cordova, California, U.S.A.) in sheep (n = 7) and calves (n = 12). For each data set, the pump speed was increased at increments of 500 rpm until left ventricular and left atrial emptying was observed by left atrial pressure diminishing to zero. The effect of decreasing preload was evaluated perioperatively by inferior vena cava occlusion at a constant pump speed. Fourier analysis established a relationship between changes in the pump preload and the power spectra of the pump current waveform. Based on these results, a control method was devised to avoid ventricular collapse and maintain the preload within a physiologic range. The objective of this controller is the minimization of the second and third harmonic of the periodic current waveform. This method is intended to provide a noninvasive regulation of the pump by eliminating the need for extraneous transducers.

Cerebrovascular accidents in patients with a ventricular assist device

OBJECTIVE

A cerebrovascular accident is a devastating adverse event in a patient with a ventricular assist device. The goal was to clarify the risk factors for cerebrovascular accident.

METHODS

Prospectively collected data, including medical history, ventricular assist device type, white blood cell count, thrombelastogram, and infection, were reviewed retrospectively in 124 patients.

RESULTS

Thirty-one patients (25%) had 48 cerebrovascular accidents. The mean ventricular assist device support period was 228 and 89 days in patients with and without cerebrovascular accidents, respectively (P < .0001). Sixty-six percent of cerebrovascular accidents occurred within 4 months after implantation. Actuarial freedom from cerebrovascular accident at 6 months was 75%, 64%, 63%, and 33% with the HeartMate device (Thoratec Corp, Pleasanton, Calif), Thoratec biventricular ventricular assist device (Thoratec Corp), Thoratec left ventricular assist device (Thoratec), and Novacor device (WorldHeart, Oakland, Calif), respectively. Twenty cerebrovascular accidents (42%) occurred in patients with infections. The mean white blood cell count at the cerebrovascular accident was greater than the normal range in patients with infection (12,900/mm3) and without infection (9500/mm3). The mean maximum amplitude of the thrombelastogram in the presence of infection (63.6 mm) was higher than that in the absence of infection (60.7 mm) (P = .0309).

CONCLUSIONS

The risk of cerebrovascular accident increases with a longer ventricular assist device support period. Infection may activate platelet function and predispose the patient to a cerebrovascular accident. An elevation of the white blood cell count may also exacerbate the risk of cerebrovascular accident even in patients without infection. Selection of device type, prevention of infection, and meticulous control of anticoagulation are key to preventing cerebrovascular accident.

Results of a multicenter clinical trial with the Thoratec Implantable Ventricular Assist Device⁎⁎Thoratec Corporation, Pleasanton, Calif

OBJECTIVE

The Thoratec Implantable Ventricular Assist Device (Thoratec Corporation, Pleasanton, Calif) can be used for univentricular or biventricular support in patients with a body surface area as low as 1.3 m(2). Results of the multicenter clinical trial are reviewed.

METHODS

Between October 2001 and June 2004, a total of 39 patients at 12 institutions were supported with the Thoratec Implantable Ventricular Assist Device. Twenty-four patients (62%) received left ventricular assist devices and 15 (38%) received biventricular assist devices. Indications included bridge to transplantation (n = 30) and postcardiotomy failure (n = 9). The control group included 100 patients from the Food and Drug Administration approval submissions for the paracorporeal version of the ventricular assist device.

RESULTS

Twenty-eight male and 11 female patients, with mean age of 48 years (16-71 years) and body surface area of 1.9 m(2) (1.3-2.4 m2) were supported for 3938 patient-days (10.8 patient-years). Mean left ventricular assist device flow index on the first postoperative day was 2.5 +/- 0.5 L/(min x m2). Mean duration of support was 101 days (9-597 days). Eighteen patients were discharged after a mean duration of 96 days. There were no ventricular assist device failures. Complications included 13 cases of bleeding requiring reexploration (33.3%), 1 embolic and 2 hemorrhagic strokes (7.7%), 5 driveline infections (12.8%), and 2 pocket infections (5%). Support to successful outcomes was 70% for bridge to transplantation and 67% for postcardiotomy recovery, versus historical results for the paracorporeal ventricular assist device of 69% for bridge to transplantation and 48% for postcardiotomy recovery.

CONCLUSION

The Thoratec Implantable Ventricular Assist Device is a new implantable pulsatile ventricular assist device that allows hospital discharge for patients as a bridge to transplantation or for postcardiotomy failure. It is the first Food and Drug Administration-approved implantable ventricular assist device with biventricular capability.

Rates and Risk Factors for Nonadherence to the Medical Regimen After Adult Solid Organ Transplantation

BACKGROUND

Despite the impact of medical regimen nonadherence on health outcomes after organ transplantation, there is mixed and conflicting evidence regarding the prevalence and predictors of posttransplant nonadherence. Clinicians require precise information on nonadherence rates in order to evaluate patients' risks for this problem.

METHODS

A total of 147 studies of kidney, heart, liver, pancreas/kidney-pancreas, or lung/heart-lung recipients published between 1981 and 2005 were included in a meta-analysis. Average nonadherence rates were calculated for 10 areas of the medical regimen. Correlations between nonadherence and patient psychosocial risk factors were examined.

RESULTS

Across all types of transplantation, average nonadherence rates ranged from 1 to 4 cases per 100 patients per year (PPY) for substance use (tobacco, alcohol, illicit drugs), to 19 to 25 cases per 100 PPY for nonadherence to immunosuppressants, diet, exercise, and other healthcare requirements. Rates varied significantly by transplant type in two areas: immunosuppressant nonadherence was highest in kidney recipients (36 cases per 100 PPY vs. 7 to 15 cases in other recipients). Failure to exercise was highest in heart recipients (34 cases per 100 PPY vs. 9 to 22 cases in other recipients). Demographics, social support, and perceived health showed little correlation with nonadherence. Pretransplant substance use predicted posttransplant use.

CONCLUSIONS

The estimated nonadherence rates, overall and by transplant type, allow clinicians to gauge patient risk and target resources accordingly. Nonadherence rates in some areas--including immunosuppressant use--appear unacceptably high. Weak correlations of most patient psychosocial factors with nonadherence suggest that attention should focus on other classes of variables (e.g., provider-related and systems-level factors), which may be more influential.

Ventricular Assist Device Support in Children and Adolescents as a Bridge to Heart Transplantation

BACKGROUND

Mechanical circulatory support using ventricular assist devices (VADs) is a life-saving option for children in heart failure refractory to maximal medical management. The aim of this study was to evaluate the efficacy of standard adult VADs in adolescents and children as well as report our early experience with miniaturized VADs in small children.

METHODS

A 15-year retrospective review was performed on all patients younger than 18 years of age undergoing insertion of a pulsatile VAD at our institution.

RESULTS

Eighteen patients underwent VAD placement during the study period. The mean age was 12 (range, 6 months to 18 years), with a mean body surface area of 1.48 (range, 0.25 to 2.3 m2). Diagnoses included dilated cardiomyopathy (n = 15), myocarditis (n = 2), and postcardiotomy ventricular failure (n = 1). Ten children underwent insertion of biventricular VADs, and 8 had implantation of left ventricular VADs. The mean support duration was 57 days (range, 2 to 175 days). Complications included bleeding requiring reoperation (n = 4), stroke (n = 5), and device-related infection (n = 2). Outcomes of VAD support were as follows: VAD explantation in 1 case, death while receiving mechanical support in 3 patients, and successful transplantation in 14 patients (77%). Survival at 6 months after orthotopic heart transplantation was 93% with 1-year and 5-year survival rates of 83%.

CONCLUSIONS

Currently available VADs are applicable for use as a bridge to orthotopic heart transplantation or in rare instances for myocardial recovery. The increasing accessibility of miniaturized devices allow for long-term support in smaller children and infants while awaiting orthotopic heart transplantation. Although the perioperative morbidity and mortality of VAD placement is not insignificant, survival for those who receive a heart transplant is excellent.

Omental Transposition Flap for Salvage of Ventricular Assist Devices

BACKGROUND

The use of ventricular assist devices for patients with end-stage cardiac failure awaiting heart transplantation has become increasingly common. Ventricular assist devices improve the longevity and the quality of life for these patients. In addition, they serve as a bridge to cardiac allograft transplantation until a donor heart is found. However, ventricular assist device-related infections remain a major problem complicating their long-term use. Clinical infection and sepsis can critically threaten these patients with ventricular assist devices. Infection can delay immediate transplantation and potentially require the removal of the device for definitive treatment of the problem.

METHODS

Patients who underwent insertion of a ventricular assist device at the University of Pittsburgh Medical Center were identified through accessing the medical records archives of the hospital. Review of patients' medical records was conducted to obtain patient demographics, preoperative diagnosis and disease state, type of ventricular assist device inserted, postoperative day of ventricular assist device infection onset, infectious organism identified, timing of omental flap procedure after the initial insertion, duration of ventricular assist device support before cardiac transplantation, and patient follow-up.

RESULTS

There were 76 patients who underwent a ventricular assist device insertion procedure during the 4-year period between January of 2000 and January of 2004. Of the 76 patients who received a device, 11 (14 percent) had evidence of clinical infection secondary to insertion. Two of these 11 patients died before surgical intervention, four had their devices explanted, and the remaining five underwent omental flap transposition with bilateral pectoralis major advancement flaps in surgically addressing their infections. Of the five patients with infections who received omental transposition flaps, two went on to undergo successful transplantation, two continue to await cardiac allograft transplantation, and one died as a result of an unknown cause.

CONCLUSIONS

The authors present their experience with five patients who received omental transposition flaps to cover infected ventricular assist device pumps and the associated tubing in large, open sternoabdominal wounds. Treatment included the direct application of an omental transposition flap over the infected device with use of a bilateral pectoralis advancement flap to aid in complete sternal and skin closure of the sternal wound defect. In each of these cases, the use of the omental flap was followed by resolution of the mediastinal infection. In addition, the treatment with an omental flap prevented the removal of infected devices in patients who were otherwise pump dependent during their waiting periods for transplantation. The use of omental transposition flaps can be an effective technique in salvaging infected ventricular assist devices and preserving this valuable device for patients awaiting a cardiac transplant.

Trajectories of change in quality of life in 12-month survivors of lung or heart transplant

Survival and functional outcomes for lung transplant recipients continue to lag behind those for heart recipients. Whether these poorer physical outcomes translate into poorer quality of life (QOL) for lung recipients relative to heart recipients is unknown. Lung versus heart transplant recipients' perceptions of QOL were longitudinally compared at three time-points across the first year posttransplant. Additionally, potentially important predictors of patient QOL were examined. Adult transplant recipients (N = 199) participated in semi-structured interviews that included measures of QOL, optimism, mastery, social support, religiosity and coping. Temporal patterns of QOL change were compared between lung and heart recipients who survived until 1 year posttransplant using mixed-model, hierarchical analysis of variance (ANOVA). Demographic and psychosocial predictors were examined with multiple regression analysis to identify the unique effects of each variable on QOL 1 year posttransplant. While heart recipients' QOL across several domains was higher shortly after transplant, lung patients' QOL improved and was equivalent to that of heart recipients by 1 year posttransplant. Greater optimism and support from friends predicted better QOL in physical, psychological and social domains. Conversely, avoidant coping strategies predicted poorer physical functioning. Thus, while clinical interventions designed to improve QOL posttransplant should be tailored to transplant recipients' initial psychosocial assets and liabilities, they need not be distinguished by transplant type.

Multicenter retrospective analysis of cardiovascular risk factors affecting long-term outcome of de novo cardiac transplant recipients

BACKGROUND

Previous risk factor studies in cardiac transplant patients have analyzed pre-transplant risk factors as they relate to outcomes. This study is the first in-depth multicenter assessment of ongoing post-transplant risk factors in heart transplant patients and their impact on 5-year outcomes.

METHODS

We reviewed 280 heart transplant patients who survived > 1 year for the impact of post-transplant risk factors (hyperlipidemia, hypertension, diabetes, body mass index [BMI] and renal dysfunction: 8 to 18 possible measurements over 5 years) on outcomes, including death, cardiac allograft vasculopathy (CAV) and non-fatal major adverse cardiac events (NF-MACE).

RESULTS

Upon multivariate Cox regression analysis, significant findings were high total-cholesterol for NF-MACE (relative risk [RR] = 4.34, confidence interval [CI] 1.35 to 13.98, p = 0.01), presence of diabetes for NF-MACE (RR = 3.96, CI 1.24 to 12.65, p = 0.02) and high serum creatinine for graft death (RR = 1.59, CI 1.35 to 1.87, p < 0.001). No covariates were found to be significant for CAV. Other significant risk factors by univariate Cox regression models with time-dependent covariates included BMI > or = 33 for graft death.

CONCLUSIONS

Post-transplant risk factors of hypercholesterolemia and diabetes are associated with NF-MACE, whereas high serum creatinine and BMI > or = 33 are associated with graft death. Risk factor modification, including direct therapy to minimize risk factors, should be considered.

The PediaFlow pediatric ventricular assist device

The very limited options available to treat ventricular failure in patients with congenital and acquired heart diseases have motivated the development of a pediatric ventricular assist device (VAD). Our effort involves a consortium consisting of the University of Pittsburgh, Carnegie Mellon University, Children's Hospital of Pittsburgh, World Heart Corporation, and LaunchPoint Technologies, LLC. The overall aim of our program is to develop a highly reliable, biocompatible VAD for chronic support (6 months) of the unique and high-risk population of children between 3 kg and 15 kg (patients from birth to 2 years of age). The innovative pediatric VAD we are developing (PediaFlow) is based on a miniature mixed-flow turbodynamic pump featuring magnetic levitation, with the design goal being to assure minimal blood trauma and risk of thrombosis. This article discusses the limitations of current pediatric cardiac assist treatment options and the work to date by our consortium toward the development of a pediatric VAD.

Biventricular assist device utilization for patients with morbid congestive heart failure: a justifiable strategy

BACKGROUND

The rationale for the use of a biventricular assist device (BiVAD) for morbid congestive heart failure (MCHF) has been questioned because of historically unacceptable rates of postimplant and post-transplant mortality as well as perceived barriers to their outpatient management.

METHODS AND RESULTS

All patients who received a Thoratec BiVAD from January 1990 to December 2003 at the University of Pittsburgh were studied retrospectively. There were a total of 73 patients (32% ischemic, 21% idiopathic, and 47% other) who had a BiVAD implanted. Before implantation, 100% were on > or =1 inotropic agent, and 77% had an intra-aortic balloon pump. Overall survival was 69%; 42 patients (84%) received cardiac transplantation, 5 patients (10%) were weaned, and 3 (6%) remained supported on BiVAD. If the 14 patients with postcardiotomy failure and acute myocardial infarction with shock are excluded, the overall survival improves to 75%. Five-year actuarial survival after heart transplantation was 58%. Of the 29 patients implanted before 2000, the 4-month actuarial freedom from driveline infections, bloodstream infections, and neurological events was 10%, 54%, and 48%, respectively, whereas the rates of these events for the 44 patients implanted after 2000 improved to 70%, 79%, and 80%, respectively. Since 2000, 21 (48%) patients were discharged from the hospital, of whom 38% went to an outpatient residence, 33% to a skilled nursing facility, and 29% to home. Once discharged, > or =1 readmission occurred in 45% and > or =2 readmissions in 48%.

CONCLUSIONS

BiVAD support for MCHF has an acceptable overall mortality and survival to transplantation. Morbidity has been significantly reduced in the past 4 years, and management as an outpatient is achievable.

Myocardial recovery using ventricular assist devices: prevalence, clinical characteristics, and outcomes

BACKGROUND

Ventricular assist devices (VADs) are important bridges to cardiac transplantation. VAD support may also function as a bridge to ventricular recovery (BTR); however, clinical predictors of recovery and long-term outcomes remain uncertain. We examined the prevalence, characteristics, and outcomes of BTR subjects in a large single center series.

METHODS AND RESULTS

We implanted VADs in 154 adults at the University of Pittsburgh from 1996 through 2003. Of these implants, 10 were BTR. This included 2/80 (2.5%) ischemic patients (supported 42 and 61 days, respectively). Both subjects had surgical revascularization, required perioperative left VAD support, and were alive and transplant-free at follow up (232 and 1319 days, respectively). A larger percentage of nonischemic patients underwent BTR (8/74, 11%; age 30+/-14; 88% female; left ventricular ejection fraction 18+/-6%; supported 112+/-76 days). Three had myocarditis, 4 had post-partum cardiomyopathy (PPCM), and 1 had idiopathic cardiomyopathy. Five received biventricular support. After explantation, ventricular function declined in 2 PPCM patients who then required transplantation. Ventricular recovery in the 6 nonischemic patients surviving transplant-free was maintained (left ventricular ejection fraction 54+/-5%; follow-up 1.5+/-0.9 years). Overall, 8 of 10 BTR patients are alive and free of transplant (follow-up 1.6+/-1.1 years).

CONCLUSIONS

In a large single center series, BTR was evident in 11% of nonischemic patients, and the need for biventricular support did not preclude recovery. For most BTR subjects presenting with acute inflammatory cardiomyopathy, ventricular recovery was maintained long-term. VAD support as BTR should be considered in the care of acute myocarditis and PPCM.

Differential Exercise Performance on Ventricular Assist Device Support

BACKGROUND

Ventricular assist devices (VADs) are approved for destination therapy because they improve survival in end-stage heart failure (HF). VADs are powered pneumatically or electrically. Pneumatic and electric left ventricular assist devices (LVADs) and biventricular assist devices (BiVADs) provide excellent hemodynamic support at rest, but differences in their effects on exercise tolerance are unclear. We sought to evaluate the effect of devices with varying operating parameters on exercise capacity.

METHODS

Exercise physiology data obtained during maximal exercise with on-line gas-exchange analysis were collected for 38 consecutive VAD-implanted HF patients referred for exercise testing.

RESULTS

Electric LVADs were implanted in 18 patients, and pneumatic LVADs in 10 patients. Percent of predicted peak exercise oxygen consumption (VO2%) was significantly greater in pneumatic LVAD patients (52.1 +/- 11.1% vs 38.2 +/- 11.3%, p < 0.05). The 10 patients implanted with a pneumatically powered LVAD were compared to 10 patients implanted with a pneumatically powered BiVAD. LVAD-supported patients had a higher VO2% (52.1 +/- 11.1% vs 36.5 +/- 17.7%, p < 0.05).

CONCLUSIONS

HF patients supported with a pneumatic LVAD appear to have better exercise tolerance than those receiving an electric LVAD. Patients on LVAD support have better exercise tolerance than BiVAD-supported patients. This highlights the importance of right ventricular function to exercise tolerance in HF patients, and may have implications for future VAD design.

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.

Profiles and predictors of the course of psychological distress across four years after heart transplantation

BACKGROUND

Like individuals exposed to other life stressors, patients undergoing organ transplantation typically show elevated psychological distress initially post-transplant, with improvement thereafter. However, this 'average' pattern may conceal subgroups with differing profiles of psychological response. We sought to identify unique temporal distress profiles, and their predictors, after heart transplantation.

METHOD

A total of 156 transplant recipients (refusal rate, 6%) were enrolled and assessed at 2, 7, 12, 36, and 42 months post-transplant. Cluster analysis was used to identify distinct distress profiles over time. Multivariate analyses examined health and psychosocial predictors of the profiles.

RESULTS

Five groups were identified, with either: (a) low distress at all time-points (45% of the sample), (b) high, clinically significant distress at all times (21%), (c) high distress over several years with low distress only at final assessment (12%), (d) high distress during the first several months with decline thereafter (6%), or (e) fluctuating distress levels (16%). Patients showing any distress (versus none) were more likely to have a pre-transplant psychiatric history, poorer social supports and more physical impairment early post-transplant, and continued physical impairment over time. Among distressed patients, those with persistent (versus declining) distress were most likely to be female, waited more briefly for transplant, and were most physically impaired early post-transplant. While persistently distressed patients had better social supports early post-transplant, these supports subsequently worsened.

CONCLUSIONS

Individuals differ in whether and when psychological distress abates after heart transplantation. Findings regarding distress profiles and their predictors may inform the design of interventions to address each transplant recipient's unique psychological needs.

Daclizumab to prevent rejection after cardiac transplantation

BACKGROUND

Daclizumab, a humanized monoclonal antibody against the interleukin-2 receptor, reduced the risk of rejection without increasing the risk of infection among renal-transplant recipients and, in a single-center trial, among cardiac-transplant recipients. We conducted a multicenter, placebo-controlled, double-blind study to confirm these results in cardiac-transplant patients.

METHODS

We randomly assigned 434 recipients of a first cardiac transplant treated with standard immunosuppression (cyclosporine, mycophenolate mofetil, and corticosteroids) to receive five doses of daclizumab or placebo. The primary end point was a composite of moderate or severe cellular rejection, hemodynamically significant graft dysfunction, a second transplantation, or death or loss to follow-up within six months.

RESULTS

By six months, 104 of 218 patients in the placebo group had reached the primary end point, as compared with 77 of the 216 patients in the daclizumab group (47.7 percent vs. 35.6 percent, P=0.007), a 12.1 percent absolute risk reduction and a 25 percent relative reduction. The rate of rejection was lower in the daclizumab group than in the placebo group (41.3 percent vs. 25.5 percent). Among patients reaching the primary end point, the median time to the end point was almost three times as long in the daclizumab group as in the placebo group during the first 6 months (61 vs. 21 days) and at 1 year (96 vs. 26 days). More patients in the daclizumab group than in the placebo group died of infection (6 vs. 0) when they received concomitant cytolytic therapy.

CONCLUSIONS

Daclizumab was efficacious as prophylaxis against acute cellular rejection after cardiac transplantation. Because of the excess risk of death, concurrent or anticipated use of cytolytic therapy with daclizumab should be avoided.

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.

Onset, timing and risk for depression and anxiety in family caregivers to heart transplant recipients

BACKGROUND

Family members adopt key caregiving roles in the maintenance of transplant recipients' health. While the bulk of the caregiving literature suggests that rates of psychiatric disorder should be high in these caregivers, the potential benefits of transplantation may instead lead to less distress than in other caregiving situations. We examined prevalence and risk factors for depressive and anxiety-related disorders in caregivers throughout 3 years after their family member's heart transplant.

METHOD

A total of 190 caregivers (97% of eligible respondents) were enrolled. They received psychiatric and psychosocial evaluations at 2, 7, 12 and 36 months post-transplant. Survival analysis determined cumulative rates of psychiatric disorders and the impact of potential risk factors.

RESULTS

Rates of depressive and anxiety-related disorders met or exceeded other caregiver populations' rates. By 3 years post-transplant, cumulative onset rates were: Major Depressive Disorder (MDD), 31.6%, Adjustment disorders, 35.4% (29.4 % with anxious mood); Post-Traumatic Stress Disorder related to the transplant (PTSD-T), 22.5%, Generalized Anxiety Disorder, 7.3%, and any assessed disorder, 56.3%. PTSD-T occurred primarily during the first year post-transplant. Other disorders' rates increased over the entire study period. Risk for disorder was elevated by positive lifetime history of psychiatric disorder, greater post-transplant caregiving responsibilities, and a poorer relationship with the patient. Risk for MDD was further increased by caregiver unemployment, and risk for anxiety disorders was further increased by younger age, low sense of personal mastery, and high use of avoidance coping strategies.

CONCLUSIONS

Transplantation is associated with costs and benefits for not only patients but family caregivers. Caregivers' risk for psychiatric illness should be considered when developing interventions to promote families' long-term adjustment to the transplant process.

An internet-based intervention to improve psychosocial outcomes in heart transplant recipients and family caregivers: development and evaluation

BACKGROUND

Although quality of life (QOL) is generally improved by heart transplantation, medical noncompliance and mental health and QOL limitations often emerge and persist. Transplant teams' ability to address these issues is hampered because many patients reside long distances from the transplant program. We therefore conducted the first empirical evaluation of an internet-based psychosocial intervention for heart recipients and their families.

METHODS

Based on focus group work and previous research, a multifaceted web-based intervention was developed with stress and medical regimen management workshops; monitored discussion groups; access to electronic communication with the transplant team; and information on transplant-related health issues. Intervention effectiveness was evaluated with 20 patients and family caregivers who used the website for 4 months (plus usual clinical care). Pre- and post-intervention assessments of mental health, QOL and medical compliance were performed. Comparison groups of 40 patients and their caregivers who received only usual care were similarly assessed.

RESULTS

Relative to the comparison groups, intervention patients' depressive and anxiety symptoms, and caregivers' anxiety and hostility symptoms declined significantly (P < 0.05). QOL in social functioning significantly improved. Mental health and QOL benefits were greater among more frequent users of the website. Overall, intervention patients' medical compliance did not change. However, the sub-group using the website's medical regimen workshop showed significantly better compliance at follow-up than all other patients in attending clinic appointments, completing blood work and following diet.

CONCLUSIONS

These preliminary findings suggest that a web-based intervention could have a vital role in follow-up care and in patients' and families' adjustment to heart transplantation.

Non-invasive assessment of myocardial recovery on chronic left ventricular assist device: results associated with successful device removal

BACKGROUND

Myocardial recovery may occur in patients with heart failure who are receiving left ventricular assist-device support, but identification of candidates for device removal remains challenging. We hypothesized that on-line quantitative echocardiography during trials of decreased device support alone or in combination with exercise cardiopulmonary testing can assess cardiac recovery to predict successful device removal.

METHODS

We studied 18 patients with severe heart failure, aged 45 +/- 19 years, who received 234 +/- 169 days of assist-device support as a bridge to transplantation. We used echocardiographic automated border detection from mid-ventricular short-axis images and non-invasive arterial pressure to measure beat-to-beat responses in 2 to 5 minute trials of decreased device flow. We also assessed maximal oxygen consumption in 14 patients who could exercise.

RESULTS

Six patients experienced myocardial recovery and underwent successful device removal; 12 remained device dependent. With transient, low assist-device flow, patients with device removal had increased echocardiographic stroke area of 27% +/- 36% vs -24% +/- 12% (p < 0.05) and fractional area change of 51% +/- 13% vs 23% +/- 11% (p < 0.05) in the patients who were device dependent. Estimates of pre-load-adjusted maximal power, a relatively load-independent index, were 6.7 +/- 2.1 mW/cm(4) in patients with successful device removal vs 1.2 +/- 1.2 mW/cm(4) in patients who were device dependent (p < 0.005). Maximal oxygen consumption was 17.2 +/- 1.4 ml/kg/min in patients with myocardial recovery vs 13.1 +/- 1.9 ml/kg/min in patients who were device dependent (p < 0.005) and correlated with pre-load-adjusted maximal power (r = 0.89, p < 0.001). Maximal oxygen consumption >16 ml/kg/min, increased stroke area, >40% increase in fractional area change, or pre-load-adjusted maximal power >4.0 mW/cm(4) with low device flow were associated with successful device removal (p < 0.05).

CONCLUSIONS

On-line quantitative echocardiography alone or combined with exercise cardiopulmonary testing can assess myocardial recovery of patients receiving left ventricular assist-device support and has the potential to identify patients who are clinical candidates for device removal.

Psychosocial vulnerability, physical symptoms and physical impairment after lung and heart-lung transplantation

BACKGROUND

Many lung and heart-lung transplant recipients experience distressing physical symptoms and elevated physical impairment levels. Although post-transplant complications and secondary illnesses may largely account for these health limitations, patients' psychosocial well-being may influence them as well. We examined the contribution of psychosocial variables to patients' experience of physical symptoms and physical impairment.

METHODS

The study consisted of a cross-sectional sample of 50 patients (36 lung, 14 heart-lung) at between 2 and 17 months post-transplant. They were interviewed to assess physical symptoms, current physical impairment and psychosocial well-being in the areas of mental health, sense of mastery and coping. Medical record reviews established the presence of medical complications and secondary illnesses concurrent with the interviews. Descriptive analyses examined the range of symptoms and levels of physical impairment experienced. Bivariate analyses and multivariate linear regression examined relationships between key variables.

RESULTS

Average number of physical symptoms and level of physical impairment met or exceeded levels reported in other transplant samples. Elevated depressive and anxiety symptoms, a low sense of mastery, and the presence of concurrent medical complications were each associated with increased number of physical symptoms and physical impairment level. When the impact of concurrent medical complications was controlled, recipients with elevated psychologic distress remained significantly more likely to report more physical symptoms and higher physical impairment levels.

CONCLUSIONS

Patients' physical health status may be influenced by many factors. To the extent that psychologic distress increases the likelihood of perceived physical limitations, timely identification and treatment of distress may help to maximize quality of life after lung and heart-lung transplantation.

Distal thoracic aorta hemodynamics during exercise with continuous flow left ventricular assist system

OBJECTIVES

Continuous flow left ventricular assist systems (LVAS) are being discussed as a destination therapy. LVAS patients will have expanded activity of daily life, including exercise. In this study, we analyzed the effects of exercise on blood flow in the distal thoracic aorta of LVAD implanted animals.

METHODS

Five calves with a continuous flow LVAS exercised on treadmill at two different pump flow rates (PFR), 60-80% (high PFR) and 25-30% (low PFR) of pulmonary artery flow rate. Pump, pulmonary artery and descending thoracic aorta flow waves were recorded before, during and after exercise. Systolic and diastolic flow volume in each cardiac cycle in pump and descending thoracic aorta flow was calculated.

RESULTS

(1) Average flow rates - Pulmonary artery and descending thoracic aorta flow rates increased with heart rate during exercise and there was no difference between groups. (2) Pump flow wave - Pump regurgitation increased temporally during exercise at both PFRs, but sustained incidences of regurgitation after exercise were only observed at low PFR. Systolic and diastolic pump flow volume decreased during exercise at both PFRs, but systolic volume increased and diastolic volume decreased significantly after exercise at low PFR. (3) Descending thoracic aorta flow wave - At high PFR, systolic volume of descending thoracic aorta increased but diastolic flow volume decreased during exercise. At low PFR, both systolic and diastolic volume of the descending thoracic aorta decreased during exercise, but systolic volume increased and diastolic volume decreased after exercise. Systolic volume of the descending thoracic aorta in low PFR was significantly greater and diastolic volume was less than those in high PFR during and after exercise.

CONCLUSION

Exercise temporarily increases pump regurgitation with continuous flow LVAS support. Average flow rate of the descending thoracic aorta was maintained by compensation from increased heart rate, although the diastolic flow of the descending thoracic aorta decreased after exercise at the lower pump flow rate. Further study will be needed to evaluate whether or not this flow decrease causes hemodynamic and/or an oxygen delivery mismatch to peripheral tissue.

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.

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.

LVAD bloodstream infections: therapeutic rationale for transplantation after LVAD infection

INTRODUCTION

Patients who have ventricular assist devices (VADs) and experience bloodstream infection (BSI) have high mortality. We addressed 2 questions raised by the United Network for Organ Sharing (UNOS) priority policy for this problem: 1) Are organs wasted on this ultra-high-risk group? 2) Can device-related BSI be differentiated from transient BSI?

METHODS

Patients with VADs who underwent heart transplantation from 1987 to 2001, who had BSI during VAD support, and who had positive cultures at VAD explant (device-related BSI, n = 10) were compared with those with negative cultures at explant (non-device-related BSI, n = 11).

RESULTS

Patients with device-related BSI had an 80% (8/10) rate of persistent bacteremia; 30 days and 1 year after transplantation, mortality was 14% and 26%, respectively. Non-device-related BSI (n = 11) persisted in 18% (2/11); peri-operative and 1-year mortalities were 9% and 13%. Duration of VAD support predicted infection (132 vs 48 days, p < 0.001); hypo-albuminemia (2.9 +/- 0.5 mg/dl vs 3.3 +/- 0.8 mg/dl, p < 0.05), and a resistant organism predicted a device-related BSI. These patients had increased intubation requirements and had increased creatinine concentration during the first post-operative week, with no difference in liver function, blood loss, transfusions (packed red blood cells, fresh frozen plasma, or platelets), or hemodynamic stability vs patients with non-device BSI. Despite decreased immunosuppression, we found no difference in acute rejection events with device-related BSI. Re-infection with the pre-operative organism occurred in only 1 patient per group.

CONCLUSIONS

These data suggest that urgent (Status 1A) cardiac transplantation is effective in stable patients with device-related BSI, and these data support the current UNOS policy. However, an extra-device source of BSI should be excluded by considering the isolated organism, the baseline nutritional status, and other risk factors.

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.

Selected patients listed for cardiac transplantation may benefit from defibrillator implantation regardless of an established indication

BACKGROUND

End-stage heart failure (HF) patients are at high risk of sudden cardiac death. This study evaluates the role of implantable cardiac defibrillators (ICDs) in HF patients awaiting cardiac transplantation.

METHODS

We identified 194 consecutive patients (age 51 +/- 12 years) with New York Heart Association Class 3 or 4 HF (ejection fraction 22 +/- 9%) listed for cardiac transplantation, 35 of whom underwent ICD implantation. Of the implanted patients, 16 (Group A) had an established indication for ICD implantation (cardiac arrest, n = 10; sustained ventricular tachycardia [VT], n = 3; and positive electrophysiology study, n = 3). Nineteen patients (Group B) underwent ICD implantation for non-established indications (syncope with non-ischemic cardiomyopathy, n = 4; non-sustained VT, n = 15). There were no procedural complications from ICD implantation.

RESULTS

During follow-up of 9.2 +/- 10.1 months, there were 3 deaths in the ICD groups (A and B), and 40 in the control group (8.6% vs 25.2%, p = 0.032). Five patients in Group A and 6 in Group B (31%) received appropriate ICD therapy. The number of therapies per patient and the time to the first shock were similar between Groups A and B. Four of 6 Group B patients on outpatient inotropic therapy (67%) received appropriate ICD therapy.

CONCLUSIONS

Selected end-stage heart failure patients awaiting heart transplantation, including those without established ICD indications, are at high risk for malignant arrhythmias and may benefit from ICD implantation. Patients with ICD seem to have improved survival compared to those without ICD. Randomized prospective studies are needed to confirm these findings.

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.

Impact of beta-blocker therapy on functional capacity criteria for heart transplant listing

BACKGROUND

Peak exercise oxygen consumption is a widely used parameter to determine the need for transplant listing in patients with severe heart failure. Currently, beta-blocker therapy is known to benefit patients with severe heart failure, although it has minimal or no effects on peak exercise oxygen consumption. This raises the hypothesis that peak exercise oxygen consumption transplant-listing criteria are not valid for patients with heart failure who receive beta-blocker therapy.

METHODS

We compared outcomes in patients with chronic heart failure who underwent heart transplant evaluation with peak exercise oxygen consumption </= 14.0 ml/kg/min and who were treated with beta-blockers (n = 48) or who were not treated with beta-blockers (n = 55).

RESULTS

Outcomes were significantly better for patients treated with beta-blockers (combined end-points of death, transplantation as United Network for Organ Sharing [UNOS] Status 1 or 2, and ventricular assist device placement, p = 0.0001). The 1-year survival was 92% and 3-year survival was 71% in the patients treated with beta-blockers, and 69% and 48% in the patients not treated with beta-blockers (compared with UNOS transplant survival data of 92% 1-year and 77% 3-year survival rates).

CONCLUSIONS

Patients with chronic heart failure and severe functional impairment who were treated with beta-blockers have significantly better outcomes compared with similarly functionally impaired patients who were not treated with beta-blockers, and these patients would not be expected to derive a survival benefit from transplantation. Thus, in patients treated with beta-blockers, the use of peak exercise oxygen consumption as a criterion to list for heart transplantation may no longer be valid. Alternatively, non-usage of beta-blockers may be a criterion to list for transplantation.

Smooth muscle cell hypertrophy of renal cortex arteries with chronic continuous flow left ventricular assist

BACKGROUND

Pathophysiology of long-term continuous flow left ventricular assist is not well described. With many of these devices becoming available, it is important to examine for possible pathologic effects. In this study we examined the relationship between diminished pulsatility and pathologic changes in renal cortical arteries.

METHODS

Twenty-nine calves were implanted with various continuous flow left ventricular assist systems in a left ventricle-descending thoracic aorta bypass configuration. Pulsatility was quantified by pulse pressure and pulsatility index. Pathologic changes of the renal cortex arteries were described and evaluated by medial thickness, medial/vascular cross-sectional area ratio, and smooth muscle cell count, to quantify hypertrophy or hyperplasia. Seven calves, which underwent a sham-implant, were used as controls.

RESULTS

Systolic arterial pressure, pulse pressure, and pulsatility index were significantly lower and diastolic pressure was significantly higher than before implant in pump-implanted animals. Twenty-three of 29 pumpimplanted calves (79.3%) had medial smooth muscle cell hypertrophy in renal cortex arteries, whereas none of sham-implanted calves had any abnormal lesions. When the pump-implanted calves were grouped according to the presence of smooth muscle cell hypertrophy, there was a clear trend toward lower pump flow rate in calves with lesions. Renal function was within the normal range in all calves.

CONCLUSIONS

There appears to be a relationship between smooth muscle cell hypertrophy in renal cortex arteries and continuous flow left ventricular assist. Furthermore, although the pathologic changes are likely multifactorial, these lesions appear to be related to lower pump assist rates.

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.

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.

Quality of life outcomes after heart transplantation in individuals bridged to transplant with ventricular assist devices

BACKGROUND

Increasing numbers of individuals receive ventricular assist devices (VADs) as bridges to heart transplantation. Physical morbidity risks and benefits, and quality of life (QOL) during VAD support have been documented. Effects of pre-transplant VAD support on functional and QOL outcomes after transplantation have received no empirical attention.

METHODS

Sixty-three VAD patients who received heart transplants underwent QOL evaluations of physical functioning, emotional and cognitive well-being, and social functioning at 2, 7, and 12 months after transplant (response rate = 95%). Ninety patients who had not received VADs--matched to the VAD group on cardiac-related and sociodemographic characteristics--served as longitudinal controls.

RESULTS

Both VAD and non-VAD groups showed similar levels and similar, statistically significant (p < 0.05) improvement in physical functioning (sleep, body care, mobility, ambulation, overall functional status, number of somatic complaints) across the study period. Emotional well-being (elevated depressive, anxiety, and anger symptoms; post-traumatic stress disorder rate) was stable or improved in both groups, and VAD patients showed significantly lower anxiety rates. The VAD patients' post-transplant cognitive status was significantly poorer. The VAD patients were significantly less likely to return to employment; other social functioning measurers (daily concerns, interpersonal activities/involvement, role function) showed mixed effects. Cognitive impairment explained much of the association between VAD support and post-transplant employment.

CONCLUSIONS

Although post-transplant physical and emotional recovery is similar in VAD and non-VAD patients, VAD patients retain more cognitive impairment and show mixed changes in social functioning. Increased attention to strategies to maximize VAD patients' cognitive capacity is required to facilitate social reintegration.

Blood biocompatibility analysis in the setting of ventricular assist devices

Ventricular assist devices (VADs) are increasingly applied to support patients with advanced cardiac failure. While the benefit of VADs in supporting this patient group is clear, substantial morbidity and mortality occur during the VAD implant period due to thromboembolic and infective complications. Efforts at the University of Pittsburgh aimed at evaluating the blood biocompatibility of VADs in the clinical, animal, and in vitro setting over the past decade are summarized. Emphasis is placed on understanding the mechanisms of thrombosis and thromboembolism associated with these devices.

Downregulation of matrix metalloproteinases and reduction in collagen damage in the failing human heart after support with left ventricular assist devices

BACKGROUND

Left ventricular assist device (LVAD) support of the failing heart induces salutary changes in myocardial structure and function. Matrix metalloproteinases (MMPs) are increased in the failing heart and are induced by stretch in cardiac cells in vitro. We hypothesized that mechanical unloading may affect LV plasticity by regulating MMPs and their substrates.

METHODS AND RESULTS

LV samples were collected from patients with dilated cardiomyopathy (DCM, n=14) or ischemic cardiomyopathy (ICM, n=16) at the time of implantation of the LVAD and again during cardiac transplantation. MMP-1, -3, and -9 were measured by ELISA, MMP-2 and -9 gelatinolytic activity by gelatin zymography, and tissue inhibitors of metalloproteinases (TIMPs) by Western blot. Total soluble and insoluble collagens were separated by pepsin solubilization, and the contents were determined by quantification of hydroxyproline. The undenatured soluble collagen was measured by Sircol collagen assay. The results showed that MMP-1 and -9 were decreased, whereas TIMP-1 and -3 were increased, but there was no change in MMP-2 and -3 and TIMP-2 and -4 after LVAD support. The undenatured collagen was increased, with the ratio of undenatured to total soluble collagens increased in ICM and that of insoluble to total soluble collagens increased in DCM after LVAD support.

CONCLUSIONS

The reduced MMPs and increased TIMPs and ratios of undenatured to total soluble collagens and insoluble to total soluble collagens after LVAD support suggest that reduced MMP activity diminished damage to the matrix. These changes may contribute to the functional recovery and LV plasticity after LVAD support.

The role of diastolic pump flow in centrifugal blood pump hemodynamics

We tried to verify the hypothesis that increases in pump flow during diastole are matched by decreases in left ventricular (LV) output during systole. A calf (80 kg) was implanted with an implantable centrifugal blood pump (EVAHEART, SunMedical Technology Research Corp., Nagano, Japan) with left ventricle to aorta (LV-Ao) bypass, and parameters were recorded at different pump speeds under general anesthesia. Pump inflow and outflow pressure, arterial pressure, systemic and pulmonary blood flow, and electrocardiogram (ECG) were recorded on the computer every 5 ms. All parameters were separated into systolic and diastolic components and analyzed. The pulmonary flow was the same as the systemic flow during the study (p > 0.1). Systemic flow consisted of pump flow and LV output through the aortic valve. The ratio of systolic pump flow to pulmonary flow (51.3%) did not change significantly at variable pump speeds (p > 0.1). The other portions of the systemic flow were shared by the left ventricular output and the pump flow during diastole. When pump flow increased during diastole, there was a corresponding decrease in the LV output (Y = -1.068X + 51.462; R(insert)(2) = 0.9501). These show that pump diastolic flow may regulate expansion of the left ventricle in diastole.

Relapsing bacteremia in patients with ventricular assist device: an emergent complication of extended circulatory support

BACKGROUND

Ventricular assist devices (VAD) are currently approved for use as a bridge for transplantation. Although reports have suggested acceptable rates of survival of patients with VAD, there is little information regarding the mechanism and etiology of bacteremia in these patients.

METHODS

We prospectively followed patients who underwent VAD implantation and developed bacteremia during VAD support at the University of Pittsburgh Medical Center. Relapsing bacteremia was defined as at least two episodes of positive blood cultures with a genetically related organism on 2 different days. Species identification and susceptibility testing were performed on all isolates. Pulse field gel electrophoresis was performed on selected blood and VAD isolates.

RESULTS

Between January 1998 and August 1999, 3 patients with VAD developed relapsing bacteremia, which was treated with full courses of antibiotic agents, 2 of whom also developed VAD endocarditis. All 3 patients had documented driveline or device pocket infections with these isolates. Consecutive blood and VAD isolates were found to be genetically related within each patient.

CONCLUSIONS

These patients with bacteremia after VAD implantation had relapse due to the same strain, which may have originated from indolent driveline infection. Endovascular infection in this setting is difficult to eradicate with antibiotic agents and carries a high mortality. These patients should be considered to have priority for orthotopic heart transplantation.

Prevalence and risk of depression and anxiety-related disorders during the first three years after heart transplantation

Although poor psychological adjustment to organ transplantation appears to be a major contributor to reduced quality of life and increased physical morbidity, the prevalence and risk factors for psychiatric disorder have not been considered beyond the first 12-18 months after transplantation. The authors enrolled a representative sample of 191 heart transplant recipients in a prospective examination of the prevalence, clinical characteristics, and risk factors for DSM-III-R major depressive disorder (MDD), generalized anxiety disorder (GAD), associated adjustment disorders, and posttraumatic stress disorder related to transplant (PTSD-T) during the 3 years postsurgery. Survival analysis indicates that cumulative risks for disorder onset were MDD, 25.5%; adjustment disorders, 20.8% (17.7% with anxious mood); PTSD-T, 17.0%; and any assessed disorder, 38.3%. There was only one case of GAD. PTSD-T onset was limited almost exclusively to the first year posttransplant. Episodes of MDD (but not anxiety disorders) that occurred later posttransplant (8 to 36 months postsurgery) were more likely than early posttransplant episodes to be treated with psychotropic medications. For both MDD and anxiety disorders, later episodes were less likely to be precipitated by transplant-related stressors than other life stressors. Factors increasing cumulative risk for psychiatric disorder posttransplant included pretransplant psychiatric history, female gender, longer hospitalization, more impaired physical functional status, and lower social supports from caregiver and family in the perioperative period. Risk factors' effects were additive; the presence of an increasing number of risk factors bore a dose-response relationship to cumulative risk of disorder.

Database: relevant or not

Progress in the field of ventricular assist devices requires a more rigorous and systematic method of collecting outcomes data. A worldwide registry of device implants and results is proposed. With widespread participation, data from this registry would improve the identification of risk factors and complications, and allow for the creation of predictive models that would enhance patient selection. Professional societies should lead the development of a registry in close partnership with government and industry. Data collection using the Web, with rigorous security measures to protect patient privacy, would offer numerous advantages in efficiency and immediacy of communication for all participants.

HeartMate II left ventricular assist system: from concept to first clinical use

The HeartMate II left ventricular assist device (LVAD) (ThermoCardiosystems, Inc, Woburn, MA) has evolved from 1991 when a partnership was struck between the McGowan Center of the University of Pittsburgh and Nimbus Company. Early iterations were conceptually based on axial-flow mini-pumps (Hemopump) and began with purge bearings. As the project developed, so did the understanding of new bearings, computational fluid design and flow visualization, and speed control algorithms. The acquisition of Nimbus by ThermoCardiosystems, Inc (TCI) sped developments of cannulas, controller, and power/monitor units. The system has been successfully tested in more than 40 calves since 1997 and the first human implant occurred in July 2000. Multicenter safety and feasibility trials are planned for Europe and soon thereafter a trial will be started in the United States to test 6-month survival in end-stage heart failure.