Mechanical Circulatory Support Device Database of the International Society for Heart and Lung Transplantation: Third Annual Report—2005⁎ ⁎All figures and tables from this report, and a more comprehensive set of ISHLT registry slides are available at www.ishlt.org/registries/

TNFalpha in patients with end-stage heart failure on medical therapy or supported by a left ventricular assist device

BACKGROUND

In the heart elevated levels of TNFalpha can cause lethal heart failure, like Dilated Cardiomyopathy (DCM). The level of TNFalpha production is in part determined by promoter gene polymorphisms. We investigated whether the TNFalpha promoter gene polymorphism is in this way involved in the outcome of end-stage heart failure and predicts whether patients require left ventricular assist device (LVAD) support or can be kept on medical therapy (MT)while awaiting heart transplantation (HTx). As most patients in this study received a heart transplant, the role of the TNFalpha polymorphisms in transplant rejection was studied as well.

METHODS AND RESULTS

In twenty nine patients with DCM, 35 patients with Ischemic Heart Disease (IHD; both on MT), 26 patients on LVAD support and 61 cardiac transplant donors TNFalpha plasma level was detected by EASIA. In both patients groups high levels of TNFalpha plasma levels was observed however, in patients supported by LVAD this increase was much higher compared to patients on MT. Furthermore, this increase seems to be associated with the TNF 1 allele ('G' at position -308) instead of the TNF2 allele (A at position -308). The promoter polymorphisms at positions -238, -244 and -308 were observed by polymerase chain reaction and sequencing. Polymorphism at positions -238, -244 and -308 did not show any relevant differences between the groups. However, at position -308, a trend of a higher incidence of the TNF2 allele (an "A" at position -308) in DCM patients compared to donors was shown. The distribution of the TNF1 and TNF2 alleles was not different in patients on medical therapy compared to the patients supported by a LVAD. No association was found between patients' TNFalpha promoter gene polymorphism and rejection. However, patients that received a donor heart with the TNF2 allele developed more rejection episodes, compared to patients that received a donor heart with the TNF1 allele.

CONCLUSION

TNFalpha levels are high in patients with end-stage heart failure on MT, but even higher in patients on LVAD support. These high TNFalpha plasma levels however, are not correlated with the TNF2 allele but seems to be associated with the TNF1 allele. Furthermore, in HTx the donor TNFalpha gene seem to play a more important role in severity of acute rejection than that of the patient.

Acute heart failure and cardiogenic shock

Acute heart failure and cardiogenic shock are medical emergencies requiring urgent medical intervention. This article defines each syndrome and reviews the latest evidence regarding their clinical presentation, management and prognosis.

Domestic and foreign trends in the prevalence of heart failure and the necessity of next-generation artificial hearts: a survey by the Working Group on Establishment of Assessment Guidelines for Next-Generation Artificial Heart Systems

A series of guidelines for development and assessment of next-generation medical devices has been drafted under an interagency collaborative project by the Ministry of Health, Labor and Welfare and the Ministry of Economy, Trade and Industry. The working group for assessment guidelines of next-generation artificial hearts reviewed the trend in the prevalence of heart failure and examined the potential usefulness of such devices in Japan and in other countries as a fundamental part of the process of establishing appropriate guidelines. At present, more than 23 million people suffer from heart failure in developed countries, including Japan. Although Japan currently has the lowest mortality from heart failure among those countries, the number of patients is gradually increasing as our lifestyle becomes more Westernized; the associated medical expenses are rapidly growing. The number of heart transplantations, however, is limited due to the overwhelming shortage of donor hearts, not only in Japan but worldwide. Meanwhile, clinical studies and surveys have revealed that the major causes of death in patients undergoing long-term use of ventricular assist devices (VADs) were infection, thrombosis, and mechanical failure, all of which are typical of VADs. It is therefore of urgent and universal necessity to develop next-generation artificial hearts that have excellent durability to provide at least 2 years of event-free operation with a superior quality of life and that can be used for destination therapy to save patients with irreversible heart failure. It is also very important to ensure that an environment that facilitates the development, testing, and approval evaluation processes of next-generation artificial hearts be established as soon as possible.

VentrAssist™ left ventricular assist device: clinical trial results and Clinical Development Plan update

OBJECTIVES

To summarise the primary efficacy and safety results from the first international clinical trial with the VentrAssist left ventricular assist device and to provide an update on the VentrAssisttrade mark Clinical Development Plan.

METHODS

The first prospective, single-arm, multicentre international clinical trial with the VentrAssist in bridge-to-transplant patients (CE Mark trial) was conducted in Australia, UK and Norway between 2004 and 2006. The primary outcome measure was survival until transplant or being transplant-eligible at postoperative day 154. The number and status of other clinical trials in the VentrAssist Clinical Development Plan are also described.

RESULTS

At the completion of the CE Mark trial, 25 of the 30 patients (83%) were transplanted or transplant-eligible. There were no unexpected safety issues and no reported uncontrolled stops of the VentrAssist pump. The Clinical Development Plan for the VentrAssist currently comprises seven clinical trials: two are completed, three are ongoing and two are ready for initiation. As of January 30th, 2007, a total of 87 patients have been implanted with the VentrAssist at 14 centres worldwide, yielding a total exposure time of more than 43 patient-years and a maximum implant duration of 2.7 years.

CONCLUSIONS

The efficacy and safety data from a clinical trial of the VentrAssist were favourable and resulted in gaining European regulatory approval for this indication. Notably, the survival success rate for the VentrAssist was higher than that reported for other left ventricular assist devices. The overall number of implants with the VentrAssist has now surpassed that of any other third-generation centrifugal device.

Type IV collagen degradation in the myocardial basement membrane after unloading of the failing heart by a left ventricular assist device

After left ventricular assist device (LVAD) support in patients with end-stage cardiomyopathy, cardiomyocytes decrease in size. We hypothesized that during this process, known as reverse remodeling, the basement membrane (BM), which is closely connected to, and forms the interface between the cardiomyocytes and the extracellular matrix, will be severely affected. Therefore, the changes in the myocardial BM in patients with end-stage heart failure before and after LVAD support were studied. The role of MMP-2 in this process was also investigated. Transmission electron microscopy showed that the BM thickness decreased post-LVAD compared to pre-LVAD. Immunohistochemistry indicated a reduced immunoreactivity for type IV collagen in the BM after LVAD support. Quantitative PCR showed a similar mRNA expression for type IV collagen pre- and post-LVAD. MMP-2 mRNA almost doubled post-LVAD (P<0.01). In addition, active MMP-2 protein as identified by gelatin zymography and confirmed by Western blot analysis was detected after LVAD support and in controls, but not before LVAD support. Active MMP was localized in the BM of the cardiomyocyte, as detected by type IV collagen in situ zymography. Furthermore, in situ hybridization/immunohistochemical double staining showed that MMP-2 mRNA was expressed in cardiomyocytes, macrophages, T-cells and endothelial cells. Taken together, these findings show reduced type IV collagen content in the BM of cardiomyocytes after LVAD support. This reduction is at least in part the result of increased MMP-2 activity and not due to reduced synthesis of type IV collagen.

Pre-operative redox state affects 1-month survival in patients with advanced heart failure undergoing left ventricular assist device implantation

BACKGROUND

Left ventricular assist device (LVAD) implantation has proven effective as a bridge to transplantation in end-stage heart failure patients (ESHFPs), although survival during device support is critical. Oxidative stress has been implicated in the development of heart failure, but the influence of redox state on in-hospital post-LVAD outcome has not been clarified.

METHODS AND RESULTS

In this report we describe the oxidant/anti-oxidant profiles of 15 ESHFPs before LVAD placement, 5 of whom did not survive to 1 month, and in 30 subjects without cardiac disease, representing the control group.

CONCLUSIONS

Preliminary findings suggest that adequate activity of the GPx-1-based anti-oxidant system before device placement is associated with patient survival up to 1 month, despite comparable baseline oxidative stress in patients who both survived and died (within 2 weeks post-LVAD).

Destination therapy: does progress depend on left ventricular assist device development?

The role of therapy using mechanical circulatory support devices has evolved rapidly over the last two decades. New developments in the field achieved smaller adverse events, but, currently, only minor improvements in survival were observed in published observational data. The authors discuss the development of mechanical circulatory support devices as a "destination therapy" option for patients who have end-stage heart failure and are ineligible for heart transplantation as it relates to left ventricular assist device development.

Use of a continuous-flow device in patients awaiting heart transplantation

BACKGROUND

The use of left ventricular assist devices is an accepted therapy for patients with refractory heart failure, but current pulsatile volume-displacement devices have limitations (including large pump size and limited long-term mechanical durability) that have reduced widespread adoption of this technology. Continuous-flow pumps are newer types of left ventricular assist devices developed to overcome some of these limitations.

METHODS

In a prospective, multicenter study without a concurrent control group, 133 patients with end-stage heart failure who were on a waiting list for heart transplantation underwent implantation of a continuous-flow pump. The principal outcomes were the proportions of patients who, at 180 days, had undergone transplantation, had cardiac recovery, or had ongoing mechanical support while remaining eligible for transplantation. We also assessed functional status and quality of life.

RESULTS

The principal outcomes occurred in 100 patients (75%). The median duration of support was 126 days (range, 1 to 600). The survival rate during support was 75% at 6 months and 68% at 12 months. At 3 months, therapy was associated with significant improvement in functional status (according to the New York Heart Association class and results of a 6-minute walk test) and in quality of life (according to the Minnesota Living with Heart Failure and Kansas City Cardiomyopathy questionnaires). Major adverse events included postoperative bleeding, stroke, right heart failure, and percutaneous lead infection. Pump thrombosis occurred in two patients.

CONCLUSIONS

A continuous-flow left ventricular assist device can provide effective hemodynamic support for a period of at least 6 months in patients awaiting heart transplantation, with improved functional status and quality of life. (ClinicalTrials.gov number, NCT00121472 [ClinicalTrials.gov].).

A Decade of Short-Term Outcomes in Post–Cardiac Surgery Ventricular Assist Device Implantation

Background— Previous studies showed 75% mortality before hospital discharge in patients with a ventricular assist device (VAD) placed for post–cardiac surgery shock. We examined a large national clinical database to assess trends in the incidence of post–cardiac surgery shock requiring VAD implantation, survival rates, and risk factors for mortality.

Methods and Results— We identified patients undergoing a VAD procedure after cardiac surgery at US hospitals participating in the Society of Thoracic Surgeons’ National Cardiac Database during the years 1995 to 2004. Baseline characteristics and operative outcomes were analyzed in 2.5-year increments. Logistic regression modeling was performed to provide risk-adjusted operative mortality and morbidity odds ratios. A total of 5735 patients had a VAD placed during the 10-year period (0.3% cardiac surgeries). Overall survival rate to discharge after VAD placement was 54.1%. With the earliest period (January 1995 through June 1997) used as reference, the mortality odds ratio declined to 0.72 (July 1997 through December 1999) and eventually to 0.41 (July 2002 through December 2004; P <0.0001). The combined mortality/morbidity odds ratio also declined, to 0.84 and 0.48 over identical periods ( P <0.0001). Preoperative characteristics associated with increased mortality were urgency of procedure, reoperation, renal failure, myocardial infarction, aortic stenosis, female sex, race, peripheral vascular disease, New York Heart Association class IV, cardiogenic shock, left main coronary stenosis, and valve procedure (c index=0.755).

Conclusions— After adjustment for clinical characteristics of patients requiring mechanical circulatory support, rates of survival to hospital discharge have improved dramatically. Insertion of a VAD for post–cardiac surgery shock is an important therapeutic intervention that can salvage most of these patients.

Chronic Mechanical Circulatory Support for Inotrope-Dependent Heart Failure Patients Who Are Not Transplant Candidates

OBJECTIVES

This study evaluated the impact of left ventricular assist device (LVAD) support on survival and quality of life in inotrope-dependent heart failure patients ineligible for cardiac transplantation.

BACKGROUND

The role for LVADs as a bridge to cardiac transplantation has been established, but data supporting their role as permanent therapy in nontransplant candidates are limited.

METHODS

The INTrEPID (Investigation of Nontransplant-Eligible Patients Who Are Inotrope Dependent) trial was a prospective, nonrandomized clinical trial comparing LVAD with optimal medical therapy (OMT). Fifty-five patients with New York Heart Association functional class IV symptoms who failed weaning from inotropic support were offered a Novacor LVAD. Eighteen of these patients did not receive an LVAD owing to patient preference (n = 14) or unavailability of the device (n = 4) but consented to follow-up and constitute a contemporaneous control group.

RESULTS

The LVAD and OMT patients were well matched for demographic and disease severity measures, except OMT patients had a lower mean serum sodium (128 mg/dl vs. 134 mg/dl; p = 0.001) and a higher mean blood urea nitrogen concentration (59 vs. 40; p = 0.02). The LVAD-treated patients had superior survival rates at 6 months (46% vs. 22%; p = 0.03) and 12 months (27% vs. 11%; p = 0.02). Adverse event rates were higher in the OMT group. Eighty-five percent of the LVAD-treated patients had minimal or no heart failure symptoms. Five LVAD patients and 1 OMT patient improved sufficiently while on therapy to qualify for cardiac transplantation.

CONCLUSIONS

Inotrope-dependent heart failure patients who are ineligible for transplantation have a high short-term mortality rate and derive a significant survival advantage from "destination" mechanical circulatory support.

Guidelines for anaesthesiologist specialist training in pain medicine

The Section and Board of Anaesthesiology of the European Union of Medical Specialists aims (EUMS/UEMS) at harmonization of training of anaesthesiologists and at improvement of patient care throughout Europe. Pain medicine is considered to be an area of expertise in anaesthesiology although exclusivity is not claimed. The Section and Board has approved both a core syllabus for pain medicine to be part of the specialist training in anaesthesiology and an additional qualification in pain medicine following the completion of a 5 yr basic specialty training in anaesthesiology. These proposals were prepared by the Working Party on Pain Medicine of the Section and Board. It considers a multidisciplinary approach to pain to contribute to quality in care and has taken the initiative to set up a Multidisciplinary Joint Committee on Pain Medicine within the EUMS/UEMS, for which these guidelines define the area of expertise of anaesthesiology.

Outcomes of left ventricular assist device implantation as destination therapy in the post-REMATCH era: implications for patient selection

BACKGROUND

The landmark Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure (REMATCH) trial first demonstrated that implantation of left ventricular assist devices (LVADs) as destination therapy (DT) can provide survival superior to any known medical treatment in patients with end-stage heart failure who are ineligible for transplantation. In the present study, we describe outcomes of DT in the post-REMATCH era in the United States.

METHODS AND RESULTS

The present study included 280 patients who underwent HeartMate XVE LVAD implantation between November 2001 and December 2005. A preoperative risk score for in-hospital mortality after LVAD implantation was established in 222 patients with complete data. All patients were followed up until death or December 2006. The 1-year survival after LVAD implantation was 56%. The in-hospital mortality after LVAD surgery was 27%. The main causes of death included sepsis, right heart failure, and multiorgan failure. The most important determinants of in-hospital mortality were poor nutrition, hematological abnormalities, markers of end-organ or right ventricular dysfunction, and lack of inotropic support. Stratification of DT candidates into low (n=65), medium (n=111), high (n=28), and very high (n=18) risk on the basis of the risk score calculated from these predictors corresponded with 1-year survival rates of 81%, 62%, 28%, and 11%, respectively.

CONCLUSIONS

Appropriate selection of candidates and timing of LVAD implantation are critical for improved outcomes of DT. Patients with advanced heart failure who are referred for DT before major complications of heart failure develop have the best chance of achieving an excellent 1-year survival with LVAD therapy.

Outcomes of left ventricular assist device implantation as destination therapy in the post-REMATCH era: implications for patient selection

BACKGROUND

The landmark Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure (REMATCH) trial first demonstrated that implantation of left ventricular assist devices (LVADs) as destination therapy (DT) can provide survival superior to any known medical treatment in patients with end-stage heart failure who are ineligible for transplantation. In the present study, we describe outcomes of DT in the post-REMATCH era in the United States.

METHODS AND RESULTS

The present study included 280 patients who underwent HeartMate XVE LVAD implantation between November 2001 and December 2005. A preoperative risk score for in-hospital mortality after LVAD implantation was established in 222 patients with complete data. All patients were followed up until death or December 2006. The 1-year survival after LVAD implantation was 56%. The in-hospital mortality after LVAD surgery was 27%. The main causes of death included sepsis, right heart failure, and multiorgan failure. The most important determinants of in-hospital mortality were poor nutrition, hematological abnormalities, markers of end-organ or right ventricular dysfunction, and lack of inotropic support. Stratification of DT candidates into low (n=65), medium (n=111), high (n=28), and very high (n=18) risk on the basis of the risk score calculated from these predictors corresponded with 1-year survival rates of 81%, 62%, 28%, and 11%, respectively.

CONCLUSIONS

Appropriate selection of candidates and timing of LVAD implantation are critical for improved outcomes of DT. Patients with advanced heart failure who are referred for DT before major complications of heart failure develop have the best chance of achieving an excellent 1-year survival with LVAD therapy.

Off-Pump Insertion of Continuous Flow Left Ventricular Assist Devices

BACKGROUND AND AIM OF THE STUDY

Traditional left ventricular assist device (LVAD) implantation requires extensive dissection and use of cardiopulmonary bypass (CPB). Potential adverse effects of CPB in very ill end-stage heart failure patients include right ventricular dysfunction, end-organ injury, and bleeding. We sought to evaluate the feasibility and outcome of LVAD insertion without CPB.

METHODS

The Jarvik 2000 is an axial-flow pump newly involved in a phase I clinical trial in status I patients as a bridge to transplantation. Seven patients received this pump through thoracotomy or sternotomy with or without the use of CPB.

RESULTS

All patients had NYHA class IV heart failure with end-organ dysfunction requiring inotropic therapy. Two were in cardiogenic shock, necessitating full CPB support. Five patients had the Jarvik implanted off-CPB. The off-CPB patients were associated with decreased length of surgery, mechanical ventilation, blood transfusions, inotropic support, and hospital stay including rehabilitation. Nearly all of the patients had complete resolution of liver and kidney dysfunction.

CONCLUSION

We have demonstrated that off-CPB insertion of axial flow LVADs is feasible, safe, and potentially advantageous. Although we are encouraged by the perioperative simplicity of this strategy, we acknowledge that additional implants and comparisons of outcomes with traditional pulsatile and continuous flow device techniques will be necessary to advocate its widespread adoption.

Cardiac Transplantation: Any Role Left?

The authors analyze the question of whether heart transplantation still has a role in the current era of complex technologies. To achieve this objective, the authors first discuss the known benefits of different therapeutic modalities currently available for patients who have end-stage heart failure, including pharmacologic management, electrophysiologic therapies, high-risk surgical strategies, implantation of mechanical circulatory support device therapy, and heart transplantation. The authors then evaluate the current developments and future perspectives in the field that may influence the likelihood of heart transplantation to remain the therapeutic modality of choice for end-stage heart failure.

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.

Ventricular assist devices in children: current achievements and future perspectives

Mechanical circulatory support systems for the treatment of acute and chronic heart failure are now available for use in several clinical situations and are designed for different indications and support times. In children, particularly in small infants, extracorporeal membrane oxygenation and centrifugal pumps have been most widely used in the past. These systems are preferred for support after cardiac operations and for use in patients who have concomitant respiratory failure, but they are suitable for short-term application only and intensive care is obligatory. VADs are designed for long-term application and allow patients to be discharged home. Pneumatic pulsatile VADs have been available in pediatric sizes since 1992. Currently at our institution, 74 children have been supported with pediatric extracorporeal VADs for up to 14 months. In the past five yr, a notable rise in survival has been achieved by improvements in pump design and pre- and post-operative management. We have been able to discharge 78% of the infants under one yr old. In this review, our current VAD experience in children will be presented in the light of improvements in decision-making, device technology, and implantation techniques, and in coagulation monitoring and anticoagulation. Additionally, new developments in the field of pediatric assist devices will be presented.

Cellular coating of the left ventricular assist device textured polyurethane membrane reduces adhesion of Staphylococcus aureus

OBJECTIVE

Infections are among the most common and serious complications of ventricular assist device implantation. These infections generally occur within the first 2 months after surgery. The basis for this high incidence of infection is not well established, so a murine intravascular infection model was developed with aortic implantation of the textured polyurethane patch material currently used in HeartMate ventricular assist devices (Thoratec Corporation Pleasanton, Calif).

METHODS

Polyurethane patch material was placed in the wall of the mouse descending aorta. Mice were then infected with Staphylococcus aureus 1 or 14 days after implantation. In vitro adhesion studies were conducted with polyurethane membranes coated with endothelial cells and membranes coated with fibrinogen.

RESULTS

Mice were susceptible to infection in both dose- and time-dependent fashions. The patch material was significantly more susceptible to infection at day 1 than day 14. Immunohistologic and morphologic studies demonstrated that the CD31+ cells deposited on the membrane surface phenotypically appeared to be endothelial cells. In vitro adhesion studies of polyurethane membranes coated with endothelial cells showed them to be less susceptible to S. aureus binding than were membranes coated with fibrinogen.

CONCLUSION

Textured polyurethane membranes are less susceptible to infection as cellular deposition occurs. The time frame within which these membranes become populated with cellular material is consistent with the time-dependent clinical incidence of infection. Cellular coating of polyurethane may provide a strategy for reducing the risk of infection.

Keys to successful cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) improves functional status in selected groups of patients with heart failure and has achieved widespread use. However, approximately one-third of patients fail to benefit from CRT. Many of these failures can be attributed to improper patient selection, suboptimal left ventricular lead placement and device programming and inadequate medical therapy. This article addresses these issues and proposes an approach to improving the results of CRT.

Preclinical biocompatibility assessment of the EVAHEART ventricular assist device: Coating comparison and platelet activation

Thromboembolism and bleeding remain significant complications of ventricular assist device (VAD) support. Increasing the amount of biocompatibility data collected during preclinical studies can provide additional criteria to evaluate device refinements, while design changes may be implemented before entering clinical use. Twenty bovines were implanted with the EVAHEART centrifugal VAD for durations from 30 to 196 days. Titanium alloy pumps were coated with either diamond-like carbon or 2-methoxyethyloylphosphoryl choline (MPC). Activated platelets and platelet microaggregates were quantified by flow cytometry, including two new assays to quantify bovine platelets expressing CD62P and CD63. Temporally, all assays were low preoperatively, then significantly increased following VAD implantation, before declining to a lower, but still elevated level over 2-3 weeks. MPC-coated VADs produced significantly fewer activated platelets after implant trauma effects diminished. Three animals receiving no postoperative anticoagulation had similar amounts of circulating activated platelets and platelet microaggregates as animals receiving warfarin anticoagulation. Two new methods to quantify bovine activated platelets using antibodies to CD62P and CD63 were characterized and applied. These measures, along with previously described assays, were able to differentiate between two biocompatible coatings and assess effects of anticoagulation regimen in VAD preclinical testing.

Depressed contractile reserve and impaired calcium handling of cardiac myocytes from chronically unloaded hearts are ameliorated with the administration of physiological treatment dose of T3 in rats

AIM

Chronic cardiac unloading causes a time-dependent upregulation of phospholamban (PLB) and depression of myocyte contractility in normal rat hearts. As thyroid hormone is known to decrease PLB expression, we examined whether thyroid hormone restores the depressed contractile performance of myocytes from chronically unloaded hearts.

METHODS

Cardiac unloading was induced by heterotopic heart transplantation in isogenic rats for 5 weeks. Animals were treated with either vehicle or physiological treatment dose of 3,5,3'-triiodo-L-thyronine (T3) that does not cause hyperthyroidism for the last 3 weeks (n=20 each).

RESULTS

In vehicle-treated animals, myocyte relaxation and [Ca2+]i decay were slower in unloaded hearts than in recipient hearts. Myocyte shortening in response to high [Ca2+]o was also depressed with impaired augmentation of peak-systolic [Ca2+]i in unloaded hearts compared with recipient hearts. In vehicle-treated rats, protein levels of PLB were increased by 136% and the phosphorylation level of PLB at Ser16 were decreased by 32% in unloaded hearts compared with recipient hearts. By contrast, in the T3-treated animals, the slower relaxation, delayed [Ca2+]i decay, and depressed contractile reserve in myocytes from unloaded hearts were all returned to normal levels. Furthermore, in the T3-treated animals, there was no difference either in the PLB protein level or in its Ser16-phosphorylation level between unloaded and recipient hearts.

CONCLUSION

These results suggest that the treatment with physiological treatment dose of thyroid hormone rescues the impaired myocyte relaxation and depressed contractile reserve at least partially through the restoration of PLB protein levels and its phosphorylation state in chronically unloaded hearts.

Clinical Outcomes Are Similar in Pulsatile and Nonpulsatile Left Ventricular Assist Device Recipients

BACKGROUND

Despite concerns about the adequacy of support provided by continuous-flow left ventricular assist devices (LVADs), direct comparisons of patient characteristics and outcomes between first-generation pulsatile and second-generation nonpulsatile LVADs are absent. We hypothesized that a nonpulsatile Jarvik 2000 LVAD (Jarvik Heart, Inc, New York, NY) would result in comparable outcomes to those of similarly ill patients implanted with a pulsatile LVAD (Novacor, WorldHeart Inc, Oakland, CA; and HeartMate XVE, Thoratec, Pleasanton, CA).

METHODS

We retrospectively compared common pre-LVAD clinical characteristics and indicators of heart failure severity between 13 pulsatile and 14 nonpulsatile LVAD recipients. The outcomes analyzed were either heart transplantation, if the LVAD was intended as a bridge to transplantation, or hospital discharge if the intention was destination therapy.

RESULTS

There was no significant difference between groups in pre-LVAD disease severity indicators. Nonpulsatile LVAD recipients had a significantly smaller body surface area (1.9 +/- 0.2 m2 versus 2.1 +/- 0.2 m2, p = 0.04) and cardiopulmonary bypass time was also significantly shorter (61 +/- 34 minutes versus 110 +/- 49 minutes, p = 0.01). Aside from duration of initial intensive care unit stay (nonpulsatile, 10 +/- 16 days; pulsatile, 14 +/- 11 days; p = 0.02), there was no difference in post-LVAD outcomes: 10 of 14 nonpulsatile and 8 of 13 pulsatile LVAD patients achieved the combined end point (p = 0.69).

CONCLUSIONS

Similarly ill congestive heart failure patients benefited equally well from either a nonpulsatile or a pulsatile LVAD. This may support an expanded role for nonpulsatile LVADs in the treatment of severe heart failure.

Designs for Mechanical Circulatory Support Device Studies

BACKGROUND

There is increased interest in mechanical circulatory support devices (MCSDs), such as implantable left ventricular assist devices (LVADs), as "destination" therapy for patients with advanced heart failure. Because patient availability to evaluate these devices is limited and randomized trials have been slow in enrolling patients, a workshop was convened to consider designs for MCSD development including alternatives to randomized trials.

METHODS AND RESULTS

A workshop was jointly planned by the Heart Failure Society of America and the US Food and Drug Administration and was convened in March 2006. One of the panels was asked to review different designs for evaluating new MCSDs. Randomized trials have many advantages over studies with no controls or with nonrandomized concurrent or historical controls. These advantages include the elimination of bias in the assignment of treatments and the balancing, on average, of known and unknown baseline covariates that influence response. These advantages of randomization are particularly important for studies in which the treatments may not differ from one another by a large amount (eg, a head-to-head study of an approved LVAD with a new LVAD). However, researchers have found it difficult to recruit patients to randomized studies because the number of clinical sites that can carry out the studies is not large. Also, there is a reluctance to randomize patients when the control device is considered technologically inferior. Thus ways of improving the design of randomized trials were discussed, and the advantages and disadvantages of alternative designs were considered.

CONCLUSIONS

The panel concluded that designs should include a randomized component. Randomized designs might be improved by allowing the control device to be chosen before randomization, by first conducting smaller vanguard studies, and by allowing crossovers in trials with optimal medical management controls. With use of data from completed trials, other databases, and registries, alternative designs that include both a randomized component (eg, 2:1 allocation for new device versus control) and a nonrandomized component (eg, concurrent nonrandomized control, historical control, or a comprehensive cohort design) should be evaluated. This will require partnerships among academic, government, and industry scientists.

Advanced suction detection for an axial flow pump

An automatic detection system for ventricular collapse was developed and tested in a first clinical trial as part of a physiological speed control concept for axial flow pumps. From this clinical experience, and based on the acquired data during this trial, an optimization of the developed system was performed. An already-existing database of 784 individual cases was extended. For harmonization of this database an additional 412 snap files were extracted from continuous data recordings and classified manually using a standardized procedure. The already-developed and clinically tested algorithms were supplemented by one additional indicator derived from a preexisting criterion. One threshold value was replaced by application of a numerically optimized nonlinear characteristic curve dependent on heart rate. Finally, in a multidimensional optimization process of the entire suction detection system, 7 individual indicators were adjusted by using 17 independent threshold values. The optimization criteria were applied using a three-level hierarchical system. Within the final database consisting of 1196 snap shots the overall amount of maldetections could be reduced to 23 cases including 5 false positive events (0.42%) and 18 false negative decisions (1.5%). By application of the clinical experience from the first clinical trial of a physiologic control system it became possible to optimize the sensitivity and specificity of the suction detection system to unprecedented accuracy.

Infection in ventricular assist devices: the role of biofilm

Ventricular assist devices improve hemodynamics in patients with heart failure, but like most implantable medical devices, they are prone to infection; organisms that are adept at forming biofilm cause most of these. Biofilm confers many advantages to the organisms, including protecting them against natural host defenses and antimicrobial therapies. This review will focus on the mechanisms of biofilm formation, including quorum sensing and subsequent changes in microbial gene and protein expression. Novel therapies targeting these processes, as well as improvements in device design and clinical management, have begun to emerge and will aid in the management of these recalcitrant infections.

Levosimendan Treatment After Primary Organ Failure in Heart Transplantation: A Direct Way to Recovery?

Heart transplantation is considered nowadays the gold standard in the therapy of chronic and terminal heart insufficiency. Primary organ failure after heart transplantation is a severe complication generally related to prolonged ischemia time, poor quality of the organ, or acute rejection. All these factors can potentially lead to multiorgan failure. Pharmacological and mechanical support for these patients is limited and often related to side effects. Ca sensitizers have been proposed to increase cardiac contractility without altering intracellular Ca levels, thus avoiding the side effects of Ca overload. We report two cases of heart transplanted patients suffering from acute graft failure in the early postoperative period who recovered after intravenous administration of levosimendan, a Ca sensitizer.

Mechanical circulatory support therapy as a bridge to transplant or recovery (new advances)

PURPOSE OF REVIEW

Large pulsatile left ventricular assist devices have been used as bridge-to-transplant therapy for the past 20 years. Over the past 2 years, a number of smaller rotary pumps have been introduced into clinical trials in the United States, Europe, and Australia. These devices offer the potential for smaller operations, greater resistance to infection, and new opportunities for bridge-to-recovery therapy.

RECENT FINDINGS

Ongoing trials with axial flow devices support greater durability and less device-related infection than the HeartMate XVE (Thoratec Corporation, Pleasanton, California, USA). A greater tendency for pump thrombus and a higher anticoagulation requirement, however, are disadvantages compared with the HeartMate device.

SUMMARY

Large pulsatile left ventricular assist devices have been the mainstay of mechanical support. The combination of durability and smaller pump size has become a focus of mechanical circulatory support in the current era. Ongoing clinical trials in the United States with three rotary pumps in both bridge-to-transplant and destination trials will likely result in a major increase in options for circulatory support. At least five other small, durable devices have recently entered non-US trials and are poised for clinical studies in the US. The National Institutes of Health-sponsored Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) will facilitate the introduction of new technology and study patient and device outcomes.

Progress versus precision: challenges in clinical trial design for left ventricular assist devices

New left ventricular assist devices promise fewer adverse events but, currently, only minor improvements in survival. Small (survival) treatment effects, limited patient populations, and the increasing number of left ventricular assist devices in development challenge the efficient conduct of premarketing trials (especially in destination therapy) and, maybe more importantly, hamper innovation. Novel trial designs would facilitate this process. Among a range of trial designs, we opt for small randomized trials, which would preserve the advantages of randomization and also allow for a shorter enrollment period. We also advocate an evidence shift toward postmarketing studies, with the Interagency Registry of Mechanically Assisted Circulatory Support providing a robust infrastructure.

Ethics Guidelines for Destination Therapy

The introduction of the left ventricular assist device as a destination therapy for patients with heart failure introduces several ethical issues. These issues are discussed to help destination therapy teams design ethically sound policies and procedures. This article addresses ethical issues pertaining to informed decision making, device failure, and change out, as well as guidelines for deactivation, fair employment of medical and psychosocial criteria, the nature of destination therapy as an elective end-of-life therapy, and advance care planning strategies.

Evaluation of cardiac function based on ventricular pressure-volume relationships during assistance with a rotary blood pump

Nowadays, a rotary blood pump can be used as not only for a bridge to transplantation (BTT) but also for a bridge to recovery (BTR) and a destination therapy (DT). In such cases, evaluation of the recovery level of the native heart provides useful information to improve the clinical strategy and decide adequate timing for removing of the RBP. In contrast, the indices for cardiac function have been studied. However, most of them do not consider the assistance with the RBP. In this study, we aimed at evaluating whether Emax, which is an index for cardiac function based on the pressure-volume relationships, is still valid during assistance with the RBP from an animal experiment. In the acute animal experiment with an adult goat, we measured pressure-volume (P-V) loops while cardiac function was normal, augmented or diminished. The experimental results revealed that there were typical differences in the shapes of P-V loops when the cardiac function was altered, and Emax can still be used as an index for the cardiac function even if the assistance with the RBP is ongoing.