Cardiac transplant outcome of patients supported on left ventricular assist device vs. intravenous inotropic therapy

The influence of mechanical Circulatory support on post-transplant outcomes in pediatric patients: A multicenter study from the International Society for Heart and Lung Transplantation (ISHLT) Registry

BACKGROUND

Mechanical circulatory support (MCS) is increasingly being used as a bridge to transplant in pediatric patients. We compare outcomes in pediatric patients bridged to transplant with MCS from an international cohort.

METHODS

This retrospective cohort study of heart-transplant patients reported to the International Society for Heart and Lung Transplantation (ISHLT) registry from 2005-2017 includes 5,095 patients <18 years. Pretransplant MCS exposure and anatomic diagnosis were derived. Outcomes included mortality, renal failure, and stroke.

RESULTS

26% of patients received MCS prior to transplant: 240 (4.7%) on extracorporeal membrane oxygenation (ECMO), 1,030 (20.2%) on ventricular assist device (VAD), and 54 (1%) both. 29% of patients were <1 year, and 43.8% had congenital heart disease (CHD). After adjusting for clinical characteristics, compared to no-MCS and VAD, ECMO had higher mortality during their transplant hospitalization [OR 3.97 & 2.55; 95% CI 2.43-6.49 & 1.42-4.60] while VAD mortality was similar [OR 1.55; CI 0.99-2.45]. Outcomes of ECMO+VAD were similar to ECMO alone, including increased mortality during transplant hospitalization compared to no-MCS [OR 4.74; CI 1.81-12.36]. Patients with CHD on ECMO had increased 1 year, and 10 year mortality [HR 2.36; CI 1.65-3.39], [HR 1.82; CI 1.33-2.49]; there was no difference in survival in dilated cardiomyopathy (DCM) patients based on pretransplant MCS status.

CONCLUSION

Survival in CHD and DCM is similar in patients with no MCS or VAD prior to transplant, while pretransplant ECMO use is strongly associated with mortality after transplant particularly in children with CHD. In children with DCM, long term survival was equivalent regardless of MCS status.

Sensitivity to perioperative ischemia/reperfusion injury in male and female donor myocardium

Many functions of the cardiovascular apparatus are affected by gender. The aim of our study was find out whether markers of cell death present in the donor myocardium differ in male and female hearts. The study involved 81 patients undergoing heart transplantation from September 2010 to January 2013. Patients were divided into two groups: male allograft (n=49), and female allograft (n=32). Two types of myocardial cell death were analyzed. High-sensitive cardiac troponin T as a necrosis marker and protein bcl-2, caspase 3 and TUNEL as apoptosis markers were measured. We observed a significantly higher level of high-sensitive cardiac troponin T after correcting for predicted ventricular mass in female donors before transplantation as well as in the female allograft group after transplantation throughout the monitored period (P=0.011). There were no differences in apoptosis markers (bcl-2, caspase 3, TUNEL) between male and female hearts before transplantation. Both genders showed a significant increase of TUNEL-positive myocytes one week after transplantation without differences between the groups. Moreover, there were no differences in caspase 3 and bcl-2 expression between the two groups. Our results demonstrated the presence of necrotic and apoptotic cell death in human heart allografts. High-sensitive cardiac troponin T adjusted for predicted ventricular mass as a marker of myocardial necrosis was higher in female donors, and this gender difference was even more pronounced after transplantation.

Effect of Pretransplant Continuous-Flow Left Ventricular Assist Devices on Cellular and Antibody-Mediated Rejection and Subsequent Allograft Outcomes

The aim of this study was to evaluate the impact of continuous-flow left ventricular assist devices (CF-LVAD) on subsequent rejection after heart transplantation (HT) by using cellular rejection score and antibody-mediated rejection score (AMRS) and correlating with subsequent allograft outcomes. We retrospectively analyzed 108 consecutive patients who underwent HT without (n = 67) or with (n = 41) previous CF-LVAD in 2008 to 2014. The 24 months cumulative effect of rejection was calculated by using cellular rejection scores and AMRS, based on the total number of rejections divided by valid biopsy samples. Vasculopathy was assessed both by routine coronary angiogram and intravascular ultrasound. Patients who underwent pretransplant CF-LVAD demonstrated a significant increase in the number of cellular rejection episodes as compared with the nonbridged patients, for 1 and 2 years of follow-up (p = 0.026 and p = 0.016), respectively. There were no differences in AMRS (p >0.05) and allograft outcomes, such as vasculopathy and overall survival (p >0.05) over the period of follow-up. Implantation of a CF-LVAD before HT impacts cellular rejection during the post-transplant period. Despite these findings, CF-LVAD does not translate to differences in allograft outcomes after transplant, such as vasculopathy and overall survival over the period of the study. In conclusion, whether this affects longer term outcomes than studied remains to be determined.

Characteristics and Outcomes of Patients Bridged to Cardiac Transplantation on Centrifugal Ventricular Assist Devices: A Case Series of the Early Experience of One Canadian Transplant Centre

BACKGROUND

Centrifugal ventricular assist devices (VADs) have been used successfully to bridge patients in cardiogenic shock to cardiac transplantation, though complications are frequent and often life-threatening.

PURPOSE

To describe characteristics and examine outcomes of patients bridged to cardiac transplantation on centrifugal VADs.

METHODS

A retrospective health record review was conducted on all adults over a 12 year period (N=20) placed on centrifugal VADs with the intent to bridge to cardiac transplantation at a major Canadian transplant centre.

RESULTS

Complications of VAD support necessitated removal of 12 patients from the transplant list; seven (35%) survived to cardiac transplantation. Of the seven recipients, five survived to discharge and four remain alive and well.

CONCLUSIONS

Bridging patients on centrifugal VADs to cardiac transplantation requires improvement, including maintaining patient stability during the period of early VAD institution, aggressively managing complications of VAD support, and consideration of long-term pulsatile devices. However, if patients survive to transplantation, good long-term outcomes are expected.

Targeting the Innate Immune Response to Improve Cardiac Graft Recovery after Heart Transplantation: Implications for the Donation after Cardiac Death

Heart transplantation (HTx) is the ultimate treatment for end-stage heart failure. The number of patients on waiting lists for heart transplants, however, is much higher than the number of available organs. The shortage of donor hearts is a serious concern since the population affected by heart failure is constantly increasing. Furthermore, the long-term success of HTx poses some challenges despite the improvement in the management of the short-term complications and in the methods to limit graft rejection. Myocardial injury occurs during transplantation. Injury initiated in the donor as result of brain or cardiac death is exacerbated by organ procurement and storage, and is ultimately amplified by reperfusion injury at the time of transplantation. The innate immune system is a mechanism of first-line defense against pathogens and cell injury. Innate immunity is activated during myocardial injury and produces deleterious effects on the heart structure and function. Here, we briefly discuss the role of the innate immunity in the initiation of myocardial injury, with particular focus on the Toll-like receptors and inflammasome, and how to potentially expand the donor population by targeting the innate immune response.

Comparison of 2-Year Outcomes of Extended Criteria Cardiac Transplantation Versus Destination Left Ventricular Assist Device Therapy Using Continuous Flow

Alternatives have emerged for patients ineligible for cardiac transplantation under standard criteria. The purpose of our study was to compare outcomes in patients ineligible for cardiac transplantation under standard criteria, treated either with extended criteria cardiac transplantation (ECCT) or a continuous flow destination therapy left ventricular assist device (CF DT-LVAD). From 2005 to 2012, patients treated with either ECCT or CF DT-LVAD at our institution were retrospectively analyzed. In the overall unmatched cohort, we examined mortality and other outcomes, including index hospitalization length of stay, renal function, stroke, and readmission rates. After propensity score (PS) matching, outcomes were compared between ECCT and CF DT-LVAD recipients. Overall, 62 patients underwent ECCT, and 146 patients were treated with CF DT-LVAD. The 2-year mortality estimate for ECCT recipients was 27.3% (95% confidence interval 15.5% to 39.1%) and for CF DT-LVAD recipients was 11.2% (95% confidence interval 4.8% to 17.6%). After PS matching of 39 patients from each treatment group, there was no significant difference in overall survival after 2 years (p = 0.346). In both unmatched and PS-matched analyses, CF DT-LVAD patients compared with ECCT had a significantly higher estimated glomerular filtration rate at 1 year but also had significantly higher hospital readmission rates. Stroke also more commonly occurred after CF DT-LVAD compared with ECCT (17 vs 5, unmatched; and 2 vs 1, PS matched). However, there was no significant difference between PS-matched groups in 2-year stroke-free survival (p = 0.371). In conclusion, ECCT and CF DT-LVAD in select patients are comparable therapies with respect to 2-year survival.

Outcomes and risk factors for heart transplantation in children with end-stage cardiomyopathy†

OBJECTIVES

Heart transplantation (HT) is the treatment of choice in children with end-stage cardiomyopathy. Several clinical, morphological, demographic, donor and recipient transplant factors have been demonstrated to affect survival in those patients following listing for HT and following HT. We aim to report our single institution results of HT in children with cardiomyopathy, and explore variables affecting survival and the need for heart retransplantation (RHT).

METHODS

Between 1988 and 2013, 125 children with cardiomyopathy underwent HT. Competing risks analysis modelled events after HT (RHT, death without RHT). Multivariable regression analysis examined risk factors affecting outcomes and parametric models were used to compare survival between diverse groups of patients.

RESULTS

There were 62 males (50%). Cardiomyopathy types were dilated (n = 104, 83%), restrictive (n = 10, 8%), chemotherapy-induced (n = 7, 6%), and other (n = 4, 3%). Median age at listing was 6.9 years and median age at HT was 7.0 years with median waiting list duration of 29 days. Thirty-four patients were infants <1 year. At time of HT, 106 patients (85%) were at United Network for Organ Sharing status-1, 25 (20%) were ventilated and 17 (14%) had mechanical circulatory support. There was 1 operative death. Competing risks analysis showed that at 10 years following HT, 10% of patients have undergone RHT, 32% have died without RHT and 58% of patients were alive without RHT. On multivariable analysis, risk factors for death following HT were panel-reactive antibodies >10% {hazard ratio [HR]: 4.1 [95% confidence interval (CI): 1.7-9.9], P = 0.002}, age group >10 years [HR: 3.2 (95% CI: 1.4-8.1), P = 0.009] and pre-HT mechanical circulatory support [HR: 2.9 (95% CI: 1.1-7.7), P = 0.033]. Additionally, earlier era <2000 was a significant risk factor for early phase mortality [HR: 8.7 (95% CI: 1.8-42.5), P = 0.017] but not for constant or late phase mortality [HR: 0.8 (95% CI 0.3-1.8), P = 0.6]. Following RHT, 6/11 (55%) expired yielding overall parametric survival estimates of 92, 77 and 57% at 1, 5 and 15 years, respectively.

CONCLUSIONS

Despite remarkable improvement in operative mortality and 1-year survival of children undergoing HT for cardiomyopathy in the current era, that advantage is reduced at the later follow-up, especially in teenagers indicating ongoing compliance and chronic management challenges. In children requiring pre-HT mechanical support, mid-term attrition is higher despite low operative mortality.

Left ventricular assist devices as a bridge to cardiac transplantation

Heart failure remains a significant cause of morbidity and mortality, affecting over five million patients in the United States. Continuous-flow left ventricular assist devices (LVAD) have become the standard of care for patients with end stage heart failure. This review highlights the current state of LVAD as a bridge to transplant (BTT) in patients requiring mechanical circulatory support (MCS).

Ventricular assist devices or inotropic agents in status 1A patients? Survival analysis of the United Network of Organ Sharing database

BACKGROUND

Improved outcomes as well as lack of donor hearts have increased the use of ventricular assist devices (VADs), rather than inotropic support, for bridging to transplantation. Recognizing that organ allocation in the highest status patients remains controversial, we sought to compare outcomes of patients with VADs and those receiving advanced medical therapy.

METHODS

The United Network of Organ Sharing (UNOS) database was used to compare survival on the waiting list and posttransplantation survival in status 1A heart transplantation patients receiving VADs or high-dose/dual inotropic therapy or an intraaortic balloon pump( IABP), or both. Adjusted survival was calculated using Cox's proportional hazard model.

RESULTS

Adjusted 1-year posttransplantation mortality was higher among patients with VADs compared with patients receiving inotropic agents alone (hazard ratio [HR], 1.48; p<0.05). Survival remained better for patients receiving inotropic agents alone in the post-2008 era (HR, 1.36; p=0.03) and among those with isolated left-sided support (HR, 1.33; p=0.008). When patients who received IABPs were added and analyzed after 2008, the left ventricular assist device (LVAD) group had similar survival (HR, 1.2; p=0.3). Survival on the waiting list, however, was superior among patients with LVADs (HR, 0.56; p<0.05). In a therapy transition analysis, failure of inotropic agents and the need for LVAD support was a consistent marker for significantly worse mortality (HR, 1.7; p<0.05).

CONCLUSIONS

Although posttransplantation survival is better for patients who are bridged to transplantation with inotropic treatment only, the cost of failure of inotropic agents is significant, with a nearly doubled mortality for those who later require VAD support. Survival on the waiting list appears to be improved among patients receiving VAD support. Careful selection of the appropriate bridging strategy continues to be a significant clinical challenge.

Post-transplant outcomes of children bridged to transplant with the Berlin Heart EXCOR Pediatric ventricular assist device

BACKGROUND

Recent data suggest that Berlin Heart EXCOR Pediatric (EXCOR) ventricular assist device improves waiting list survival for pediatric heart transplant candidates. Little is known about their post-transplant outcomes. The aim of this analysis was to determine whether there was a difference in early survival for children bridged to transplant with EXCOR versus status 1A pediatric heart transplant patients not transplanted with ventricular assist device support.

METHODS AND RESULTS

Pediatric heart transplant patients (n=106) bridged to transplantation with EXCOR were compared with a similarly aged cohort (n=1021) within the Organ Procurement and Transplant Network (OPTN) database (both cohorts from May 2007 to December 2010). In the EXCOR group, 12-month post-transplant survival (88.7%) was similar to OPTN patients listed status 1A who were not on ventricular assist device support at transplant (89.3%; P=0.85) and significantly better than 12-month survival in OPTN patients on extracorporeal membrane oxygenation at transplant (60.3%; P<0.001). Rejection (50%) was a significantly (P=0.005) higher cause of 12-month post-transplant mortality in the EXCOR compared with the OPTN group. Death after transplant was also higher in EXCOR patients with congenital heart disease compared with those with cardiomyopathy (26.1% versus 7.2%; P=0.02). Post-transplant survival was similar in EXCOR patients with ≥1 serious adverse event during ventricular assist device support as those without an event during support.

CONCLUSIONS

The 12-month post-transplant survival with EXCOR is comparable with overall pediatric heart transplant survival and superior to survival after extracorporeal membrane oxygenation. Neither adverse events during support nor factors associated with mortality during support influence post-transplant survival. Rejection was a significantly greater cause of post-transplant mortality in EXCOR than in OPTN patients.

Risk stratification of ambulatory patients with advanced heart failure undergoing evaluation for heart transplantation

BACKGROUND

Risk stratification of ambulatory heart failure (HF) patients has relied on peak VO(2)<14 ml/kg/min. We investigated whether additional clinical variables might further specify risk of death, ventricular assist device (VAD) implantation (INTERMACS <4) or heart transplantation (HTx, Status 1A or 1B) within 1 year after HTx evaluation. We hypothesized that right ventricular stroke work index (RVSWI), pulmonary capillary wedge pressure (PCWP) and the model for end-stage liver disease-albumin score (MELD-A) would be additive prognostic predictors.

METHODS

We retrospectively collected data on 151 ambulatory patients undergoing HTx evaluation. Primary outcomes were defined as HTx, LVAD or death within 1 year after evaluation.

RESULTS

Average age in our cohort was 55 ± 11.1 years, 79.1% were male and 39% had an ischemic etiology (LVEF 21 ± 10.5% and peak VO(2) 12.6 ± 3.5 ml/kg/min). Fifty outcomes (33.1%) were observed (27 HTxs, 15 VADs and 8 deaths). Univariate logistic regression showed a significant association of RVSWI (OR 0.47, p = 0.036), PCWP (OR 2.65, p = 0.007) and MELD-A (OR 2.73, p = 0.006) with 1-year events. Stepwise regression showed an independent correlation of RVSWI<5gm-m(2)/beat (OR 6.70, p < 0.01), PCWP>20 mm Hg (OR 5.48, p < 0.01), MELD-A>14 (OR 3.72, p< 0.01) and peak VO(2)<14 ml/kg/min (OR 3.36, p = 0.024) with 1-year events. A scoring system was developed: MELD-A>14 and peak VO(2)<14-1 point each; and PCWP>20 and RVSWI<5-2 points each. A cut-off at≥4 demonstrated a 54% sensitivity and 88% specificity for 1-year events.

CONCLUSIONS

Ambulatory HF patients have significant 1-year event rates. Risk stratification based on exercise performance, left-sided congestion, right ventricular dysfunction and liver congestion allows prediction of 1-year prognosis. Our findings support early and timely referral for VAD and/or transplant.

Preoperative serum albumin levels predict 1-year postoperative survival of patients undergoing heart transplantation

BACKGROUND

Serum albumin concentration has been recognized as a marker of nutrition, severity of inflammation, and hepatic function in patients with various chronic diseases. The purpose of this study was to investigate the impact of pretransplant serum albumin concentration on post-transplant outcome in heart transplant recipients.

METHODS AND RESULTS

Preoperative laboratory variables, including albumin concentration and donor-related information, were obtained from 822 consecutive patients undergoing heart transplant at Columbia University Medical Center between 1999 and 2010. The association between pretransplant albumin concentration and post-transplant 1-year survival was analyzed. Available data from the United Network for Organ Sharing (n=13671) were also analyzed to evaluate the impact of preoperative albumin levels on post-transplant outcome. In our cohort, multivariable analysis revealed that preoperative albumin (mg/dL; hazard ratio, 0.46; P<0.0001) and preoperative total bilirubin (mg/dL; hazard ratio, 1.26; P=0.0002) were associated with post-transplant 1-year mortality. This implied that for every 1 mg/dL increase in albumin concentration, the post-transplant 1-year mortality rate decreased by 54%. The Kaplan-Meier analysis based on our patients cohort and the United Network for Organ Sharing dataset showed lower survival rate at 1-year post-transplant in patients with albumin levels ≤ 3.5 mg/dL compared with those with >3.5 mg/dL (our patients, 91.3 versus 72.4%; P<0.0001; United Network for Organ Sharing, 88.4 versus 84.8%; P<0.0001).

CONCLUSIONS

Pretransplant serum albumin concentration is a strong prognostic marker for post-transplant survival in heart transplant recipients.

Value of peak exercise oxygen consumption combined with B-type natriuretic peptide levels for optimal timing of cardiac transplantation

BACKGROUND

Peak exercise oxygen consumption (VO(2)) is widely used to select candidates for heart transplantation (HTx). However, the prognosis of patients with advanced heart failure and peak VO(2) of 10 to 14 mL/min per kg in the era of modern medical therapy for heart failure is not fully elucidated. B-type natriuretic peptide (BNP) is a useful prognostic marker in patients with heart failure.

METHODS AND RESULTS

A total of 424 patients undergoing HTx evaluation were classified according to peak VO(2) during cardiopulmonary exercise testing (>14, 10-14, and <10 mL/min per kg). Survival after cardiopulmonary exercise testing without HTx or ventricular assist device (VAD) support was compared with survival of 743 de novo HTx recipients. Multivariable analysis revealed that high BNP and low peak VO(2) were independently associated with death, HTx, or VAD requirements (hazard ratio, 3.5 and 0.6; 95% CI, 1.24-9.23 and 0.03-0.71; P=0.02 and <0.0001, respectively). VAD-free or HTx-free survival of patients with peak VO(2) 10 to 14 mL/min per kg was identical to post-HTx survival. When patients with peak VO(2) 10 to 14 mL/min per kg were dichotomized by a cutoff value of BNP of 506 pg/mL, those with BNP<506 pg/mL was equivalent to post-HTx survival (1 year: 90.8% versus 87.2%; P=0.61), whereas those with BNP≥506 showed worse VAD-free or HTx-free survival (1 year: 79.7%; P<0.001 versus post-HTx). Patients with peak VO(2) <10 mL/min per kg showed worse survival compared with post-HTx survival, and there was a survival difference between those with BNP≥506 and <506 pg/mL (1 year: 77.2% versus 56.1%; P=0.01).

CONCLUSIONS

Patients with peak VO(2) 10 to 14 mL/min per kg and low BNP levels have a VAD-free or HTx-free survival similar to post-HTx survival in heart recipients, whereas high BNP levels indicate worse outcome in this group of patients.

Can long-term ventricular assist devices be safely implanted in low-volume, non-heart transplant centres?

BACKGROUND

Mechanical circulatory support (MCS) using long-term ventricular assist devices (VADs) is an established therapy in select patients with advanced heart failure. Studies have suggested that outcomes after VAD implantation may be dependent on institutional procedural volume, and outcome data from non-transplant centres are lacking. This study reviews the outcomes of patients who received a long-term VAD at our centre to determine if these devices can be safely implanted at tertiary care, low-volume, non-transplant centres.

METHODS

We conducted a single-centre retrospective cohort study, examining the clinical outcomes of consecutive patients who received a long-term VAD over a 42-month period.

RESULTS

During the study period 73 patients required MCS, of whom 16 received a long-term VAD. This select group had a mean Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profile of 1.6 (0.9) and before implantation 94% required at least 1 inotropic medication, 69% had suffered a cardiac arrest, 63% required an intra-aortic balloon pump, 69% required mechanical ventilation, and 44% required short-term MCS. The primary outcome of survival to transplant or ongoing MCS at 1 year was achieved in 75% of patients. Operating room, intensive care unit, and hospital survival were 100%, 88%, and 81%, respectively.

CONCLUSIONS

Long-term VADs can be implanted at low-volume, nontransplant centres with survival rates comparable with contemporary clinical trials. Availability of a specialty trained multidisciplinary team with expertise in short-term and long-term MCS options facilitates appropriate patient selection and might be more important than institutional volume in determining outcomes after implantation.

Pre-operative and post-operative risk factors associated with neurologic complications in patients with advanced heart failure supported by a left ventricular assist device

BACKGROUND

Neurologic complications (NCs) are the major adverse events after left ventricular assist device (LVAD) surgery. Pre-operative and post-operative factors associated with NCs in patients with LVADs were investigated.

METHODS

We reviewed 307 consecutive patients undergoing LVAD surgery (167 HeartMate I and 140 HeartMate II devices) at Columbia University Medical Center between November 2000 and December 2010. Clinical characteristics and hemodynamic and laboratory indexes were analyzed. NC was defined according to the Interagency Registry for Mechanically Assisted Circulatory Support definition of neurologic dysfunction, including transient ischemic attack (TIA) and ischemic or hemorrhagic cerebrovascular accident (CVA).

RESULTS

NCs developed in 43 patients (14.0%) at 91.8 ± 116.3 days post-operatively. The frequency of NC development was similar in HeartMate I and II patients. Patients with NC showed a higher frequency of pre-LVAD CVA history (27.9% vs 15.5%, p = 0.046), lower pre-operative sodium (129.0 ± 7.0 vs 132.1 ± 8.1 mg/dl, p = 0.018) and albumin concentrations (3.5 ± 0.7 vs 3.7 ± 0.6 mg/dl, p = 0.049), lower post-operative hematocrit (34.9% ± 5.1% vs 37.8% ± 6.1%, p = 0.0034), sodium (131.6 ± 7.7 vs 134.4 ± 6.4 mg/dl, p = 0.010) and albumin concentrations (3.7 ± 0.5 vs 3.9 ± 0.5 mg/dl, p = 0.0016), and higher frequency of post-operative infection (39.5% vs 19.3%, p = 0.003) than those without NC. Multiple regression analysis revealed that CVA history (odds ratio, 2.37, 95% confidence interval, 1.24-5.29; p = 0.011) and post-operative infection (odds ratio, 2.99, 95% confidence interval, 1.16-10.49; p = 0.011) were highly associated with NC development. The combination of CVA history, pre-operative and post-operative sodium and albumin, and post-operative hematocrit and infection could discriminate patients developing NCs with a probability of 76.6%.

CONCLUSIONS

Previous stroke, persistent malnutrition and inflammation, severity of heart failure, and post-LVAD infections are key factors associated with development of NCs after LVAD implantation.

Effects of continuous-flow versus pulsatile-flow left ventricular assist devices on myocardial unloading and remodeling

BACKGROUND

Continuous-flow left ventricular assist devices (LVAD) are increasingly used for patients with end-stage heart failure (HF). We analyzed the effects of ventricular decompression by continuous-flow versus pulsatile-flow LVADs on myocardial structure and function in this population.

METHODS AND RESULTS

Sixty-one patients who underwent LVAD implantation as bridge-to-transplant were analyzed (pulsatile-flow LVAD: group P, n=31; continuous-flow LVAD: group C, n=30). Serial echocardiograms, serum levels of brain natriuretic peptide (BNP), and extracellular matrix biomarkers (ECM) were compared between the groups. Myocardial BNP and ECM gene expression were evaluated in a subset of 18 patients. Postoperative LV ejection fraction was greater (33.2±12.6% versus 17.6±8.8%, P<0.0001) and the mitral E/E' was lower (9.9±2.6 versus 13.2±3.8, P=0.0002) in group P versus group C. Postoperative serum levels of BNP, metalloproteinases (MMP)-9, and tissue inhibitor of MMP (TIMP)-4 were significantly lower in group P compared with group C (BNP: 552.6±340.6 versus 965.4±805.7 pg/mL, P<0.01; MMP9: 309.0±220.2 versus 475.2±336.9 ng/dL, P<0.05; TIMP4: 1490.9±622.4 versus 2014.3±452.4 ng/dL, P<0.001). Myocardial gene expression of ECM markers and BNP decreased in both groups; however, expression of TIMP-4 decreased only in group P (P=0.024).

CONCLUSIONS

Mechanical unloading of the failing myocardium using pulsatile devices is more effective as indicated by echocardiographic parameters of systolic and diastolic LV function as well as dynamics of BNP and ECM markers. Therefore, specific effects of pulsatile mechanical unloading on the failing myocardium may have important implications for device selection especially for the purpose of bridge-to-recovery in patients with advanced HF.

How does successful bridging with ventricular assist device affect cardiac transplantation outcome?

A best evidence topic in cardiac surgery was written according to a structured protocol. The issue was to determine the impact of bridge-to-transplant ventricular assist device support on survival after cardiac transplantation. Altogether 428 papers were found using the reported search, of which 12 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. The treatment options for patients with advanced heart failure or those with deteriorating end-organ function on maximal medical therapy are limited to intravenous inotropes and mechanical assistance with intra-aortic balloon pump (IABP) or ventricular assist device (VAD). Studies exploring the effect of VADs on post-transplant mortality have yielded conflicting results. The Registry of the International Society for Heart and Lung Transplantation continues to identify mechanical support as a risk factor for decreased survival after transplantation. A limitation of this report is that the multivariable adjustment uses variables recorded not at the time of device implant but at the time of transplant. Some of the recipient characteristics thus may be altered by the device implant. Compared with the previous reports the latest data show improvement in post-transplant survival in the recent era. In addition, the excess risk appears to be limited to the early post-transplant period. Experienced centers consistently report outstanding post-transplant results with left ventricular assist device (LVAD) bridging. Of the 12 papers seven showed no difference in survival, and five showed a reduced survival. In the papers showing no difference, one year survival averaged from 85% in supported patients to 87% in non-supported patients. In papers reporting a difference in outcome, one year averaged survival was 74% in LVAD recipients compared to 90% in non-bridged patients. Decreased survival is associated with patients suffering from dilated cardiomyopathy, transplanted within two weeks of LVAD implantation and bridged to transplantation before 2003 as opposed to patients transplanted more recently. Based on the available evidence we conclude that in selected patients survival after heart transplantation in patients bridged with VAD is comparable to those who did not receive the device.

The impact of bridge-to-transplant ventricular assist device support on survival after cardiac transplantation

OBJECTIVE

To determine the impact of bridge-to-transplant ventricular assist device support on survival after cardiac transplantation.

METHODS

From January 1, 1993, to April 30, 2009, a total of 525 cardiac transplants were performed. Ventricular assist devices were placed as a bridge to transplant in 110 patients. We focused our analysis on the 2 most common causes of end-stage heart failure requiring transplantation: idiopathic dilated cardiomyopathy (n = 201) and coronary artery disease (n = 213). Data including gender, age, date of transplant, cause of heart failure, prior heart transplant, placement of a ventricular assist device, type of ventricular assist device, and panel-reactive antibody sensitization were analyzed to derive Kaplan-Meier survival probabilities and multivariable Cox regression models.

RESULTS

In patients with idiopathic dilated cardiomyopathy who received a ventricular assist device as a bridge to transplant, survival was decreased at 1 year (P = .008) and 5 years (P = .019), but not at 10 years, posttransplant. In patients with coronary artery disease, the use of a ventricular assist device as a bridge to transplant did not influence survival at 1, 5, and 10 tears posttransplant. In patients with idiopathic dilated cardiomyopathy who received a Heartmate I (Thoratec Corp, Pleasanton, Calif) ventricular assist device as a bridge to a cardiac transplant, elevation in the pretransplant panel-reactive antibody correlated with a decrease in long-term survival.

CONCLUSION

In patients with idiopathic dilated cardiomyopathy, placement of a Heartmate I ventricular assist device as a bridge to a cardiac transplant is associated with an elevation in the pretransplant panel-reactive antibody and a decrease in 1- and 5-year survivals after cardiac transplantation.

Post-cardiac transplant survival after support with a continuous-flow left ventricular assist device: impact of duration of left ventricular assist device support and other variables

OBJECTIVE

Although left ventricular assist devices (LVADs) are associated with excellent outcomes in patients with end-stage heart failure, there are conflicting reports on posttransplant survival in these patients. Furthermore, prior studies with pulsatile LVADs have shown that transplantation, either early (<6 weeks) or late (>6 months) after LVAD implantation, adversely affected post-cardiac transplant survival. We sought to determine factors related to posttransplant survival in patients supported with continuous-flow LVADs.

METHODS

The HeartMate II LVAD (Thoratec Corporation, Pleasanton, Calif) was implanted in 468 patients as a bridge to transplant at 36 centers in a multicenter trial. Patients who underwent transplantation after support were stratified by demographics: gender, age, etiology, body mass index, duration of device support, and by adverse events during support. The median age was 54 years (range 18-73 years); 43% had ischemic etiology, and 18% were women. Survival was determined at the specific intervals of 30 days and 1 year after transplantation.

RESULTS

Of 468 patients, 250 (53%) underwent cardiac transplant after a median duration of LVAD support of 151 days (longest: 3.2 years), 106 (23%) died, 12 (2.6%) recovered ventricular function and the device was removed, and 100 (21%) were still receiving LVAD support. The overall 30-day and 1-year posttransplant survivals were 97% and 87%. There were no significant differences in survival based on demographic factors or LVAD duration of less than 30 days, 30 to 90 days, 90 to 180 days, and more than 180 days. Patients requiring more than 2 units of packed red blood cells in 24 hours during LVAD support had a statistically significant decreased 1-year survival (82% vs 94%) when compared with patients who did not require more than 2 units of packed red blood cells in 24 hours during LVAD support (P = .03). There was a trend for slightly lower survival at 1 year in patients with percutaneous lead infections during LVAD support versus no infection (75% vs 89%; P = .07).

CONCLUSIONS

Post-cardiac transplant survival in patients supported with continuous-flow devices such as the HeartMate II LVAD is equivalent to that with conventional transplantation. Furthermore, posttransplant survival is not influenced by the duration of LVAD support. The improved durability and reduced short- and long-term morbidity associated with the HeartMate II LVAD has reduced the need for urgent cardiac transplantation, which may have adversely influenced survival in the pulsatile LVAD era. This information may have significant implications for changing the current United Network for Organ Sharing criteria regarding listing of heart transplant candidates.

Surface coatings for ventricular assist devices

This article focuses on the surface engineering of ventricular assist devices (VADs) for the treatment of heart failure patients, which involves the modification of surfaces contacting blood in order to improve the blood compatibility (hemocompatibility) of the VADs. Following an introduction to the categorization and the complications of VADs, this article pays attention on the hemocompatibility, applications and limitations of six types of surface coatings for VADs: titanium nitride coatings, diamond-like carbon coatings, 2-methacryloyloxyethyl phosphorylcholine polymer coatings, heparin coatings, textured surfaces and endothelial cell linings. In particular, diamond-like coatings and heparin coatings are the most commonly used for VADs owing to their excellent hemocompatibility, durability and technical maturity. For high performance and a long lifetime of VADs, surface modification with coatings to ensure hemocompatibility is as important as the mechanical design of the device.

The use of continuous milrinone therapy as bridge to transplant is safe in patients with short waiting times

OBJECTIVE

The limited availability of donor organs creates a need for more effective management of heart disease when bridging a patient to cardiac transplant. Inotropic therapy is becoming more commonly used long term to maintain baseline function. The effectiveness and complications associated with their use have not been fully evaluated, and indications for mechanical versus medical therapy as a bridge have not been delineated.

METHODS AND RESULTS

The purpose of this study is to evaluate the safety and efficacy of milrinone as a bridge to transplant. This was a retrospective study of 60 patients listed for a cardiac transplant and committed to home intravenous milrinone therapy. A subgroup of patients who eventually progressed to the use of a ventricular assist device were analyzed. Complications and survivals were analyzed for each group. Forty-six patients (76%) were successfully bridged to transplant with milrinone alone, and 14 patients' (24%) conditions deteriorated and required a left ventricular assist device (LVAD); 1-year survivals were 83% and 71%, respectively. The mean waiting time was 59.5 days (9-257 days) for patients receiving milrinone who did not require an LVAD and 112 days (24-270 days) for those whose conditions deteriorated to require an LVAD.

CONCLUSIONS

This study suggests that chronic intravenous milrinone provides an adequate strategy as a bridge to transplant if the waiting time is short (<100 days), whereas an elective ventricular assist device implantation may be a safer strategy for patients expected to wait longer. These data provide the basis for a prospective evaluation of inotrope versus LVAD as a bridge to transplantation.

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.

Multivariate Predictors of Heart Transplantation Outcomes in the Era of Chronic Mechanical Circulatory Support

BACKGROUND

Determining which pretransplantation (TX) characteristics predict the development of chronic renal dysfunction (CRD) or death after heart TX would enable more accurate risk assessment at the time of candidate evaluation.

METHODS

A cohort of 278 patients underwent TX in three hospitals between 1993 and 2002. Predictive models for CRD (serum creatinine consistently above 2 mg/dL) and allograft loss (death or re-TX) were constructed using logistic and Cox regression, respectively.

RESULTS

Using logistic regression, CRD was more likely to develop in TX patients if they had a larger body surface area (odds ratio [OR] = 5.8 per m2, 95% confidence interval [CI] = 1.04 to 31.9, p = 0.04) or were inotrope dependent (OR = 1.8, 95% CI = 0.90 to 3.7, p = 0.09). Notably, the implementation of mechanical circulatory support as bridge to transplantation decreased the risk of CRD (OR = 0.30, 95% CI = 0.12 to 0.72, p = 0.007). Cox analysis demonstrated independent predictive ability of improved survival for males (hazard ratio [HR] = 0.42, 95% CI = 0.21 to 0.83, p = 0.01). Worse survival was observed with prior sternotomy (HR = 3.5, 95% CI = 2.0 to 6.0, p < 0.001), diabetes mellitus (HR = 1.9, 95% CI = 0.98 to 3.9, p = 0.06), and elevated serum creatinine (HR = 2.8 per mg/dL, 95% CI = 1.3 to 5.8, p = 0.007).

CONCLUSIONS

Certain pretransplant characteristics clearly predispose a patient to the development of CRD or increased mortality after heart transplantation. Interestingly, the risk of CRD after heart transplantation is greater for patients bridged to transplant with inotropes than with mechanical circulatory support. When hemodynamically indicated, timely implementation of pretransplant mechanical circulatory support should be considered.

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.

Heart transplant and left ventricular assist device costs

BACKGROUND

With the increasing clinical success of left ventricular assist devices (LVADs), physicians need to measure device cost efficacy to determine the societal value of this technology. Today's large clinical volume allows comparison of the costs of this innovation as compared with orthotopic heart transplant (OHT).

METHODS

We evaluated hospital cost and reimbursement for patients who were discharged after LVAD implantation and returned to the hospital for OHT. To control for patient-specific variables, LVAD therapy and OHT therapy were compared in the same patient; that is, only those patients who received an LVAD were discharged, and returned for OHT were studied. Length of stay (LOS), re-admissions and outpatient services were analyzed, including their respective total actual hospital cost (TAHC) and net revenue (NR). Time periods analyzed were the same for LVAD and OHT.

RESULTS

From the LVAD population at Columbia-Presbyterian Medical Center, 36 patients were discharged following HeartMate vented electric (VE) implantation and re-admitted for OHT between December 1996 and June 2000. Mean pre-LVAD implantation LOS was 21.3 +/- 24.1 days. Post-LVAD LOS was 36.8 +/- 22.2 days vs 18.2 +/- 12.2 days post-OHT (p < 0.001). Mean length of LVAD support was 123.4 +/- 77.7 days. Overall total costs for LVADs exceeded that of OHT, whereas revenue was relatively lower. TAHC post-LVAD averaged $197,957 +/- 77,291, whereas TAHC post-OHT averaged $151,646 +/-53,909 (p = 0.005). NR averaged $144,756 +/- 96,656 post-LVAD vs $178,562 +/- 68,571 post-OHT (p = 0.09). LVAD patients had more re-admissions compared with OHT: 1.2/123 days (+/- 1.7) vs 0.3/123 days (+/- 0.6), respectively (p = 0.005). The average LOS during a re-admission was similar between the 2 groups (LVAD 5.6 days [+/- 10.6] vs OHT 9.6 days [+/- 8.2]; p = 0.18). OHT was associated with a significantly greater number of outpatient services compared with LVAD (9.7 [+/- 6.1] vs 3.0 [+/- 4.7]; p < 0.001). In contrast to OHT, revenues did not match the costs of LVAD therapy.

CONCLUSIONS

LVAD implantation is associated with longer LOS and higher cost for initial hospitalization compared with OHT. LVAD patients have higher re-admission rates compared with OHT but similar costs and LOS. OHT is associated with a greater number of outpatient services. Reimbursements for LVAD therapy are relatively low, resulting in significant lost revenue. If LVAD therapy is to become a viable alternative, improvements in both cost-effectiveness and reimbursement will be necessary.

Right ventricular failure after left ventricular assist device implantation: the need for an implantable right ventricular assist device

Right ventricular failure after implantation of a left ventricular assist device is an unremitting problem. Consideration of portal circulation is important for reversing liver dysfunction and preventing multiple organ failure after left ventricular assist device implantation. To achieve these objectives, it is imperative to maintain the central venous pressure as low as possible. A more positive application of right ventricular assistance is recommended. Implantable pulsatile left ventricular assist devices cannot be used as a right ventricular assist device because of their structure and device size. To improve future prospects, it is necessary to develop an implantable right ventricular assist device based on a rotary blood pump.

Different clinical scenarios for circulatory mechanical support in acute and chronic heart failure

Chronic heart failure (HF) is a leading cause of death in developed countries. Over the last 2 decades, mechanical circulatory support (MCS) devices have steadily evolved in the clinical management of end-stage HF and have emerged as a standard of care for the treatment of acute and chronic HF refractory to conventional medical therapy. Possible indications for using MCS are acute cardiogenic shock, as a bridge to transplantation, as a bridge to recovery, and more recently, as destination therapy in dilated cardiomyopathy, of either ischemic or idiopathic etiology. We reviewed the different clinical scenarios in which we think there are currently indications to implant different kinds of MCS systems.

Is bridging to transplantation with a left ventricular assist device a risk factor for transplant coronary artery disease?

BACKGROUND

Left ventricular assist device (LVAD) support is associated with coagulopathy, bleeding, increased blood transfusion, and increased anti-HLA antibody production. Increased anti-HLA antibody production is associated with early transplant rejection, transplant coronary artery disease (CAD), and decreased post-transplant survival rates. We asked whether bridging to transplantation with an LVAD increases the risk of transplant CAD.

METHODS

We reviewed data for all adults (>18 years old) who underwent heart transplantation at our institution between 1988 and 2000. After exclusion of transplant recipients who survived <3 years, we divided the remaining cohort into 2 groups: those bridged to transplantation with LVADs (mean duration of support, 149 +/- 107 days, n = 29) and those in United Network for Organ Sharing Status 1 bridged to transplantation without LVADs (controls, n = 86). We compared groups in terms of disease cause, age, sex, donor age, panel-reactive antibody testing, crossmatching, pre- and post-transplant cholesterol concentrations, diagnosis of diabetes mellitus or treated hypertension, infections, calcium channel blocker use, transplant rejection, ischemic time, cytomegalovirus infection, pre-transplant transfusion, and incidence of transplant CAD (defined as any coronary lesion identified by coronary angiography). We considered p < 0.05 to be significant.

RESULTS

The bridged and control groups were similar in all respects except mean ischemic time (217 +/- 58 minutes vs 179 +/- 67 minutes, p = 0.007), post-transplant cholesterol concentration (212 +/- 55 mg/dl vs 171 +/- 66 mg/dl, p = 0.007), and pre-transplant transfusion incidence (100% vs 22%, p < 0.001). The incidence of transplant CAD was similar in both groups during a 3-year follow-up period (28% vs 17%, p = 0.238) and during total follow-up (34% vs 35%, p = 0.969). Multivariate logistic regression analysis identified cholesterol concentration at 1 year after transplantation as a significant predictor of CAD at 3 years after heart transplantation (p = 0.0029, odds ratio = 0.984).

CONCLUSIONS

Bridging to transplantation with an LVAD does not increase the risk of transplant CAD. Nevertheless, aggressive prophylactic therapy to minimize potential risk factors for transplant CAD, such as increased cholesterol concentration, is warranted in all transplant recipients.