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/

Risk factors predictive of right ventricular failure after left ventricular assist device implantation

Right ventricular failure (RVF) after left ventricular assist device (LVAD) implantation appears to be associated with increased mortality. However, the determination of which patients are at greater risk of developing postoperative RVF remains controversial and relatively unknown. We sought to determine the preoperative risk factors for the development of RVF after LVAD implantation. The data were obtained for 175 consecutive patients who had received an LVAD. RVF was defined by the need for inhaled nitric oxide for >/=48 hours or intravenous inotropes for >14 days and/or right ventricular assist device implantation. An RVF risk score was developed from the beta coefficients of the independent variables from a multivariate logistic regression model predicting RVF. Destination therapy (DT) was identified as the indication for LVAD implantation in 42% of our patients. RVF after LVAD occurred in 44% of patients (n = 77). The mortality rates for patients with RVF were significantly greater at 30, 180, and 365 days after implantation compared to patients with no RVF. By multivariate logistic regression analysis, 3 preoperative factors were significantly associated with RVF after LVAD implantation: (1) a preoperative need for intra-aortic balloon counterpulsation, (2) increased pulmonary vascular resistance, and (3) DT. The developed RVF risk score effectively stratified the risk of RV failure and death after LVAD implantation. In conclusion, given the progressively growing need for DT, the developed RVF risk score, derived from a population with a large percentage of DT patients, might lead to improved patient selection and help stratify patients who could potentially benefit from early right ventricular assist device implantation.

Cardiac fibrosis and cellular hypertrophy decrease the degree of reverse remodeling and improvement in cardiac function during left ventricular assist

BACKGROUND

This study investigated if the degree of cardiac fibrosis and myocyte size at the time of left ventricular assist device (LVAD) implantation predicts the degree of improvement in cardiac function and sustained recovery after LVAD explantation.

METHODS

The study included 34 patients who underwent LVAD-off test. LV end-diastolic (LVEDD) and end-systolic diameter (LVESD), LV ejection fraction (LVEF), mean pulmonary artery pressure (mPAP), pulmonary capillary wedge pressure (PCWP), and cardiac index (CI) were measured before LVAD implantation and during LVAD-off test. Myocardial tissue was obtained from the apical core at LVAD implantation.

RESULTS

The degree of cardiac fibrosis had significant correlations with changes in LVEDD (r = -0.725, p < 0.0001), LVESD (r = -0.800, p < 0.0001), LVEF (r = -0.637, p < 0.0001), mPAP (r = -0.569, p = 0.0010), PCWP (r = -0.463, p = 0.0123), and CI (r = -0.544, p = 0.0015). Myocyte size also had significant correlations with changes in LVEDD (r = -0.386, p = 0.0235), LVESD (r = -0.414, p = 0.0141), and LVEF (r = -0.528, p = 0.0015). The LVAD was successfully removed in 9 patients. The degree of cardiac fibrosis and myocyte size in these patients was significantly smaller compared with the patients who did not undergo LVAD removal.

CONCLUSIONS

Cardiac fibrosis and myocyte size at the time of LVAD implantation were significant predictors of degree of improvement of cardiac function and the sustained recovery after the LVAD explantation.

Risk factor analysis of long-term support with left ventricular assist system

BACKGROUND

This study was designed to elucidate the key factors for successful long-term support with a left ventricular assist system (LVAS) in the situation where heart transplantation is rarely available.

METHODS AND RESULTS

From 1992 to 2008, 106 patients underwent 121 LVAS implantations at Osaka University Hospital (Toyobo: 77; Novacor: 18; HeartMate: 14; Jarvik2000: 8; EvaHeart: 2; DuraHeart: 2). Risk factors for infection were early on the former implanted period (odds ratio (OR) 3.30), Toyobo (OR 2.25), mechanical right heart support (OR 2.30) and cardiopulmonary bypass time (OR 1.01). Left atrium as the inflow site was the risk factor for cerebrovascular events (OR 2.84). Older age (OR 1.04) and mechanical right heart support (OR 4.70) were risk factors for mortality. Risk factors for requiring mechanical right heart support were preoperative extracorporeal membranous oxygenation support (OR 5.641), serum total bilirubin (OR 1.11) and serum creatinine (OR 2.46). On the basis of the risk analysis for mortality, patients were divided into 2 subgroups (low and high risk) and the respective cumulative survival at 1 year after LVAS implantation was 75.2% and 25.0%.

CONCLUSIONS

Appropriate selection of device, patient and the timing of implantation and less invasive operation are important for successful long-term LVAS support.

Model for end-stage liver disease score predicts left ventricular assist device operative transfusion requirements, morbidity, and mortality

BACKGROUND

The Model for End-Stage Liver Disease (MELD) predicts events in cirrhotic subjects undergoing major surgery and may offer similar prognostication in left ventricular assist device candidates with comparable degrees of multisystem dysfunction.

METHODS AND RESULTS

Preoperative MELD scores were calculated for subjects enrolled in the University of Michigan Health System (UMHS) mechanical circulatory support database. Univariate and multiple regression analyses were performed to investigate the ability of patient characteristics, laboratory data (including MELD scores), and hemodynamic measurements to predict total perioperative blood product exposure and operative mortality. The ability of preoperative MELD scores to predict operative mortality was evaluated in subjects enrolled in the Interagency Registry of Mechanically Assisted Circulatory Support (INTERMACS), and results were compared with those from the UMHS cohort. The mean+/-SD MELD scores for the UMHS (n=211) and INTERMACS (n=324) cohorts were 13.7+/-6.1 and 15.2+/-5.8, respectively, with 29 (14%) and 19 (6%) perioperative deaths. In the UMHS cohort, median total perioperative blood product exposure was 74 units (25th and 75th percentiles, 44 and 120 units). Each 5-unit MELD score increase was associated with 15.1+/-3.8 units (beta+/-SE) of total perioperative blood product exposure. Each 10-unit increase in total perioperative blood product exposure increased the odds of operative death (odds ratio, 1.05; 95% confidence interval, 1.01 to 1.10). Odds ratios, measuring the ability of MELD scores to predict perioperative mortality, were 1.5 (95% confidence interval, 1.1 to 2.0) and 1.5 (95% confidence interval, 1.1 to 2.1) per 5 MELD units for the UMHS and INTERMACS cohorts, respectively. When MELD scores were dichotomized as >or=17 and <17, risk-adjusted Cox proportional-hazard ratios for 6-month mortality were 2.5 (95% confidence interval, 1.2 to 5.3) and 2.5 (95% confidence interval, 1.1 to 5.4) for the UMHS and INTERMACS cohorts, respectively.

CONCLUSIONS

The MELD score identified left ventricular assist device candidates at high risk for perioperative bleeding and mortality.

Community support of patients with a left ventricular assist device: The Toronto General Hospital experience

BACKGROUND

Implantation of a left ventricular assist device (LVAD) is an acceptable therapy for patients with advanced heart failure. LVADs may be used as a bridge to recovery, a bridge to transplantation or as destination therapy. Although the morbidity rate of individuals on device support remains high, experience suggests that patients who are discharged home have satisfactory outcomes during support and following heart transplantation.

METHODS

A retrospective review of 24 patients implanted with an LVAD between October 2001 and December 2006 was performed. Nineteen patients received a device as a bridge to transplantation and five received a device as destination therapy. Postoperative follow-up was performed routinely in the heart function/LVAD clinic at the Toronto General Hospital (Toronto, Ontario) and all adverse events were recorded.

RESULTS

The majority of patients were men, with a mean age of 44 years and a diagnosis of dilated cardiomyopathy (62%). Seventeen patients (71%) were discharged home on support; one died, 14 were transplanted, one was explanted and one patient remains on support in the community. Post-transplant survival was 93% in patients discharged home compared with 40% transplanted during their hospital stay. Outpatients spent 56% of their overall support time at home, with only 12 readmissions totalling 120 patient days.

CONCLUSIONS

LVAD patients can be safely managed in the community. Patients who are discharged home experience better outcomes in both pre- and post-transplant survival. Successful outpatient management provides a strong foundation for the establishment of destination therapy within mechanical circulatory support programs in Canada.

Surface modification of a titanium alloy with a phospholipid polymer prepared by a plasma-induced grafting technique to improve surface thromboresistance

To improve the thromboresistance of a titanium alloy (TiAl(6)V(4)) surface which is currently utilized in several ventricular assist devices (VADs), a plasma-induced graft polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) was carried out and poly(MPC) (PMPC) chains were covalently attached onto a TiAl(6)V(4) surface by a plasma induced technique. Cleaned TiAl(6)V(4) surfaces were pretreated with H(2)O-vapor-plasma and silanated with 3-methacryloylpropyltrimethoxysilane (MPS). Next, a plasma-induced graft polymerization with MPC was performed after the surfaces were pretreated with Ar plasma. Surface compositions were verified by X-ray photoelectron spectroscopy (XPS). In vitro blood biocompatibility was evaluated by contacting the modified surfaces with ovine blood under continuous mixing. Bulk phase platelet activation was quantified by flow cytometric analysis, and surfaces were observed with scanning electron microscopy after blood contact. XPS data demonstrated successful modification of the TiAl(6)V(4) surfaces with PMPC as evidenced by increased N and P on modified surfaces. Platelet deposition was markedly reduced on the PMPC grafted surfaces and platelet activation in blood that contacted the PMPC-grafted samples was significantly reduced relative to the unmodified TiAl(6)V(4) and polystyrene control surfaces. Durability studies under continuously mixed water suggested no change in surface modification over a 1-month period. This modification strategy shows promise for further investigation as a means to reduce the thromboembolic risk associated with the metallic blood-contacting surfaces of VADs and other cardiovascular devices under development.

Peripheral blood mononuclear cell transcriptome profiles suggest T-cell immunosuppression after uncomplicated mechanical circulatory support device surgery

Mechanical circulatory support device (MCSD) surgery in patients with advanced heart failure patients is often complicated by infections that are linked to altered cell-mediated immunity. Using a transcriptome-wide peripheral blood mononuclear cell (PBMC) gene expression profiling approach, we analyzed expression patterns directly before and after MCSD implantation in 11 patients who had an uncomplicated course after MCSD implantation (Day 0-24 hours before, Day 1-24 hours after, and Day 7-1 week after implantation). Data were analyzed using Significance Analysis of Microarrays (SAM) and High-Throughput GoMiner on post-implantation profiles (Day 1, Day 7) in comparison with baseline (Day 0). Day1 profiles included differential expression of 821 genes (SAM, FDR <0.1, fold change >1.5), enriching >60 Gene Ontology (GO) categories. Grouping by component genes revealed GO clusters, which we term "interleukin related" (primarily upregulated), "T-cell related" (primarily downregulated), and "apoptosis related" (both up- and down-regulated genes). Day 7 profiles included GO categories related to repair processes. In conclusion, transcriptome-wide expression profiling of PBMCs suggests a response pattern to MCSD implantation of inflammatory activation and simultaneous T-cell suppression.

Incidence and patterns of adverse event onset during the first 60 days after ventricular assist device implantation

BACKGROUND

Although ventricular assist devices (VADs) provide effective treatment for end-stage heart failure, VAD support remains associated with significant risk for adverse events (AEs). To date there has been no detailed assessment of the incidence of a full range of AEs using standardized event definitions. We sought to characterize the frequency and timing of AE onset during the first 60 days of VAD support, a period during which clinical observation suggests the risk of incident AEs is high.

METHODS

A retrospective analysis was performed utilizing prospectively collected data from a single-site clinical database including 195 patients aged 18 or greater receiving VADs between 1996 and 2006. Adverse events were coded using standardized criteria. Cumulative incidence rates were determined, controlling for competing risks (death, transplantation, recovery-wean).

RESULTS

During the first 60 days after implantation, the most common AEs were bleeding, infection, and arrhythmias (cumulative incidence rates, 36% to 48%), followed by tamponade, respiratory events, reoperations, and neurologic events (24% to 31%). Other events (eg, hemolysis, renal, hepatic events) were less common (rates <15%). Some events (eg, bleeding, arrhythmias) showed steep onset rates early after implantation. Others (eg, infections, neurologic events) had gradual onsets during the 60-day period. Incidence of most events did not vary by implant era (1996 to 2000 vs 2001 to 2006) or by left ventricular versus biventricular support.

CONCLUSIONS

Understanding differential temporal patterns of AE onset will allow preventive strategies to be targeted to the time periods when specific AE risks are greatest. The AE incidence rates provide benchmarks against which future studies of VAD-related risks may be compared.

Solutions for disparities for women with heart disease

Cardiovascular disease (CVD) mortality and morbidity is a major burden on the US and global population. Observed differences in prevalence, incidence, outcomes, and risk factors suggest a possible sex difference in etiology and pathophysiology of CVD. Disparate rates of referral and diagnosis may be attributable to differences in symptoms, presentation, and diagnostic accuracy. Many common procedural, pharmaceutical, and medical device therapies have been associated with worse outcomes in women compared to men. Awareness campaigns and efforts to improve female inclusion in clinical trials are contributing to improvements in CVD healthcare delivery for women, but much remains unknown about the biological basis for the differences described above, such as the role of estrogen, life-cycle changes (puberty, menstrual cycle, pregnancy, menopause), and possible chromosomal or genetic mechanisms. This is where translational research is uniquely poised to make immense contributions to resolving disparities in the quality of care and outcomes for women with CVD.

Covalent surface modification of a titanium alloy with a phosphorylcholine-containing copolymer for reduced thrombogenicity in cardiovascular devices

Our objective was to develop a surface modification strategy for a titanium alloy (TiAl6V4) to provide thromboresistance for surfaces in rigorous blood-contacting cardiovascular applications, such as that found in ventricular assist devices. We hypothesized that this could be accomplished by the covalent attachment of a phospholipid polymer, poly(2-methacryloyloxyethylphosphorylcholine (MPC)-co-methacryl acid) (PMA). TiAl6V4 was H2O plasma treated by radio frequency glow discharge, silanated with 3-aminopropyltriethoxysilane (APS), and ammonia plasma treated to increase surface reactivity. The TiAl6V4 surface was then modified with PMA via a condensation reaction between the amino groups on the TiAl6V4 surface and the carboxyl groups on PMA. The surface composition was verified by X-ray photoelectron spectroscopy, confirming successful modification of the TiAl6V4 surfaces with APS and PMA as evidenced by increased Si and P. Plasma treatments with H2O and ammonia were effective at further increasing the surface reactivity of TiAl6V4 as evidenced by increased surface PMA. The adsorption of ovine fibrinogen onto PMA-modified surfaces was reduced relative to unmodified surfaces, and in vitro ovine blood contact through a rocking test revealed marked reductions in platelet deposition and bulk phase platelet activation relative to unmodified TiAl6V4 and polystyrene controls. The results indicate that the PMA-modification scheme for TiAl6V4 surfaces offers a potential pathway to improve the thromboresistance of the blood-contacting surfaces of cardiovascular devices.

Who should be delisted from urgent heart transplantation in Germany?

When German heart transplant candidates receive a ventricular assist device (VAD), the indication for Eurotransplant urgency listing is no longer given unless assist device complications occur. We studied survival rates in these patients and compared them with those of patients with urgency listing. The study cohort consists of 377 heart transplant candidates who were listed in urgent status or received a VAD in our center between 2000 and 2007. We defined the following patient groups: group U (n = 193), patients listed in urgent status primarily; group VADinT (n = 219), patients actively listed without urgency (transplantable) after VAD implantation, and group VADinU (n = 99), patients listed in urgent status after VAD implantation. The survival rates during urgent status in groups U and VADinU and those during VAD support without urgency listing in group VADinT were studied. The survival curves of groups U and VADinU were similar, and 1-month survival rates were 97.7% and 95.9%, respectively. One-month survival rate in group VADinT (85.9%) was worse than in group U (p < 0.0001). Survival rates in patients in urgent status both with and without VAD are satisfactory. However, patients with a VAD in "transplantable" status should be rescued under an urgency-based resource allocation algorithm.

Ventricular assist device therapy

Ventricular assist devices are an important therapeutic option for advanced congestive heart failure. A left ventricular assist device (LVAD) can be implanted as a bridge to transplantation or for the purpose of destination therapy. LVADs improve end-organ function and reduce morbidity and mortality in appropriately selected patients. The development of axial flow pumps has overcome many of the limitations of the first-generation pulsatile flow LVADs. However, many complications of LVAD therapy remain. Treating these complications requires an understanding of LVAD physiology. Ongoing research is directed at reducing the incidence of many of these complications and may allow for wider use of LVADs.

Risk score derived from pre-operative data analysis predicts the need for biventricular mechanical circulatory support

BACKGROUND

Right ventricular (RV) failure after left ventricular assist device (LVAD) placement is a serious complication and is difficult to predict. In the era of destination therapy and the total artificial heart, predicting post-LVAD RV failure requiring mechanical support is extremely important.

METHODS

We reviewed patient characteristics, laboratory values and hemodynamic data from 266 patients who underwent LVAD placement at the University of Pennsylvania from April 1995 to June 2007.

RESULTS

Of 266 LVAD recipients, 99 required RV assist device (BiVAD) placement (37%). We compared 36 parameters between LVAD (n = 167) and BiVAD patients (n = 99) to determine pre-operative risk factors for RV assist device (RVAD) need. By univariate analysis, 23 variables showed statistically significant differences between the two groups (p < or = 0.05). By multivariate logistic regression, cardiac index < or =2.2 liters/min/m(2) (odds ratio [OR] 5.7), RV stroke work index < or =0.25 mm Hg . liter/m(2) (OR 5.1), severe pre-operative RV dysfunction (OR 5.0), pre-operative creatinine > or =1.9 mg/dl (OR 4.8), previous cardiac surgery (OR 4.5) and systolic blood pressure < or =96 mm Hg (OR 2.9) were the best predictors of RVAD need.

CONCLUSIONS

The most significant predictors for RVAD need were cardiac index, RV stroke work index, severe pre-operative RV dysfunction, creatinine, previous cardiac surgery and systolic blood pressure. Using these data, we constructed an algorithm that can predict which LVAD patients will require RVAD with >80% sensitivity and specificity.

Pediatric heart transplant candidates with failed donor heart allocation after Eurotransplant urgency listing profit from pretransplant mechanical circulatory support bridging

Due to the Eurotransplant organ allocation policy, urgency listing for heart transplantation (HTx) remains in force until ventricular assist device (VAD) implantation in Germany. We studied the prognosis of HTx candidates after failed donor heart allocation in urgent status. We studied all adult and pediatric (<18 years) HTx candidates who underwent primary HTx after Eurotransplant urgency listing between January 2001 and December 2006 (Group A-uHTx [A-"u"rgent status "HTx"], n = 99; Group P-uHTx [P-"u"rgent status "HTx"], n = 24) and those to whom donor heart was not urgently allocated before VAD implantation or death in the same period (Group A-fHA [A-"f"ailed "H"eart "A"llocation], n = 21, Group P-fHA [P-"f"ailed "H"eart "A"llocation], n = 10). Mortality rate after urgency listing or primary VAD implantation was studied in each group. In adult patients, 1-year mortality rate after urgency listing in Group A-fHA was 56.8% and significantly higher than in Group A-uHTx (30.6%, P < 0.001, log-rank test). After failed urgent heart allocation, 15 out of 21 patients in Group A-fHA had VAD implantation and two patients (9.5%) underwent HTx after VAD implantation. In pediatric patients, 1-year mortality rate in Group P-fHA was 40.0% and significantly higher than in Group P-uHTx (8.5%, P < 0.05). In Group P-fHA, all 10 patients underwent VAD implantation after failed urgent heart allocation and six patients (60.0%, P < 0.01 vs. Group A-fHA, Fisher's exact test) underwent HTx after VAD implantation. After failed urgent donor heart allocation, pediatric HTx candidates seem to profit more from mechanical circulatory support than adults.

Early planned institution of biventricular mechanical circulatory support results in improved outcomes compared with delayed conversion of a left ventricular assist device to a biventricular assist device

OBJECTIVE

It is generally accepted that patients who require biventricular assist device support have poorer outcomes than those requiring isolated left ventricular assist device support. However, it is unknown how the timing of biventricular assist device insertion affects outcomes. We hypothesized that planned biventricular assist device insertion improves survival compared with delayed conversion of left ventricular assist device support to biventricular assist device support.

METHODS

We reviewed and compared outcomes of 266 patients undergoing left ventricular assist device or biventricular assist device placement at the University of Pennsylvania from April 1995 to June 2007. We subdivided patients receiving biventricular assist devices into planned biventricular assist device (P-BiVAD) and delayed biventricular assist device (D-BiVAD) groups based on the timing of right ventricular assist device insertion. We defined the D-BiVAD group as any failure of isolated left ventricular assist device support.

RESULTS

Of 266 patients who received left ventricular assist devices, 99 (37%) required biventricular assist device support. We compared preoperative characteristics, successful bridging to transplantation, survival to hospital discharge, and Kaplan-Meier 1-year survival between the P-BiVAD (n = 71) and D-BiVAD (n = 28) groups. Preoperative comparison showed that patients who ultimately require biventricular support have similar preoperative status. Left ventricular assist device (n = 167) outcomes in all categories exceeded both P-BiVAD and D-BiVAD group outcomes. Furthermore, patients in the P-BiVAD group had superior survival to discharge than patients in the D-BiVAD group (51% vs 29%, P < .05). One-year and long-term Kaplan-Meier survival distribution confirmed this finding. There was also a trend toward improved bridging to transplantation in the P-BiVAD (n = 55) versus D-BiVAD (n = 22) groups (65% vs 45%, P = .10).

CONCLUSION

When patients at high risk for failure of isolated left ventricular assist device support are identified, proceeding directly to biventricular assist device implantation is advised because early institution of biventricular support results in dramatic improvement in survival.

Total artificial heart--concepts and clinical use

End-stage congestive heart failure remains the leading cause of death in the United States. Despite advances in medical treatment, it also remains the most common reason for admission to the hospital. The gold standard of treatment for the failing heart, orthotopic heart transplantation, is limited by a shortage of donor hearts. There are also a significant number of patients who are not transplant candidates due to comorbid conditions and/or inability to tolerate immunosuppressive therapy. To meet the need for this latter group, the medical field has embraced ventricular assist device (VAD) therapy to extend survival and improve quality-of-life for the end-stage cardiac patient. This therapy, however, has been currently limited to the failing left ventricle and is still fraught with complications that limit long-term and widespread use. The total artificial heart, as currently available with two devices, is rapidly becoming the treatment of choice for biventricular failure.

Prospective, observational study of antiplatelet and coagulation biomarkers as predictors of thromboembolic events after implantation of ventricular assist devices

BACKGROUND

Long-term success in ventricular assist device (VAD) recipients is limited by thromboembolic events, the prediction of which remains elusive. We evaluated the predictive value of aspirin hyporesponsiveness and markers of coagulation and fibrinolysis.

METHODS

We prospectively enrolled patients scheduled to undergo VAD implantation between June 2004 and March 2006. Once before surgery, daily during hospitalization, and weekly after discharge we assessed platelet function, measured prothrombin activation fragment 1.2 (F1.2) and plasminogen activator inhibitor-1 (PAI-1) concentrations, and evaluated aspirin hyporesponsiveness by whole-blood aggregometry and thromboelastography. All patients received 325 mg oral aspirin daily from at least 7 days before VAD implantation. Follow-up continued until heart transplantation, death or closure of the database.

RESULTS

We included 26 patients (median follow-up 315 days, range 9-833 days). In eight (31%) patients, 14 thromboembolic events occurred at a median of 42 (interquartile range 26-131) days. Only six (43%) events based on whole-blood aggregometry and one (7%) based on thromboelastography coincided with aspirin hyporesponsiveness. Within-patient variability was high for both tests (59% and 567%, respectively). Compared with levels before surgery, PAI-1 concentrations were raised for up to 45 days (P <0.0001) and those of F1.2 for up to 3 days (P = 0.0001) after VAD implantation. PAI-1 and F1.2 levels did not rise significantly further before thromboembolic events.

CONCLUSIONS

Aspirin hyporesponsiveness was not associated with raised risk of future clinical thromboembolic events after VAD implantation. Impaired fibrinolysis, demonstrated by raised PAI-1 concentrations, might, however, indicate a predisposition to such events early after surgery.

Outcome of noncardiac surgery in patients with ventricular assist devices

An increasing number of patients are living with ventricular assist devices (VADs). Many of these patients will require noncardiac surgery for conditions not directly related to their VADs. The aim of this study was to assess the risks and outcomes of noncardiac surgery in these patients. Perioperative and follow-up data from patients with VADs who underwent noncardiac surgery from 1993 to 2006 were analyzed. In that period, 184 VADs were implanted in 155 patients. Thirty-seven patients (24%) subsequently underwent 59 noncardiac surgeries. The mean duration of VAD support before surgery was 229 days. Bleeding was the most common postsurgical complication (10%), necessitating reexploration in 20% of abdominal surgeries. Thirty-day mortality was 12%. No deaths were caused by direct complications of surgery. Successful transplantation occurred in 72% of bridge to transplantation patients who required noncardiac surgery, compared with 71% of these patients who did not require noncardiac surgery (relative risk 1.0, p = 0.9). The average duration of VAD support after noncardiac surgery for destination therapy patients was 324 days, most of which time was spent at home. In conclusion, outcomes after noncardiac surgery in patients with VADs are favorable, and most patients continue to benefit from the intended purpose of mechanical circulatory support after recovering from noncardiac surgery.

European experience of DuraHeart magnetically levitated centrifugal left ventricular assist system

OBJECTIVE

The DuraHeart (Terumo Heart, Inc., Ann Arbor, Michigan, USA) is the world's first approved magnetically levitated centrifugal left ventricular assist system designed for long-term circulatory support. We report the clinical outcomes of 68 patients implanted with the DuraHeart as a bridge to cardiac transplantation in Europe.

METHODS

Sixty-eight patients with advanced heart failure (six females), who were eligible for cardiac transplantation were implanted with the DuraHeart between January 2004 and July 2008. Median age was 58 (range: 29-74) years with 31% over 65 years. Thirty-three of these patients received the device as a part of the European multi-center clinical trial. Survival analyses were conducted for 68 patients and other safety and performance data were analyzed based on 33 trial patients.

RESULTS

Mean support duration was 242+/-243 days (range: 19-1148, median: 161) with a cumulative duration of 45 years. Thirty-five patients (51%) remain ongoing, 18 transplanted, 1 explanted, and 14 died during support with a median time to death of 62 days. The Kaplan-Meier survival rate during support was 81% at 6 months and 77% at 1 year. Of the 13 patients (21%) supported for >1 year, 4 supported for >2 years, 1 supported >3 years, 2 transplanted, 2 died, and 9 ongoing with a mean duration of 744+/-216 days (range: 537-1148, median: 651). Major adverse events included driveline/pocket infection, stroke, bleeding, and right heart failure. There was no incidence of pump mechanical failure, pump thrombosis, or hemolysis.

CONCLUSIONS

The DuraHeart was able to provide safe and reliable long-term circulatory support with an improved survival and an acceptable adverse event rate in advanced heart failure patients who were eligible for transplantation.

Complications in patients with ventricular assist devices

Heart failure affects more than 5 million people in the United States. The treatments of this disease include medical therapy, heart transplantation, and the implantation of ventricular assist devices. These devices are used in patients who are no longer responsive to conservative medical treatment, who are not candidates for a heart transplantation (destination therapy), who are awaiting a heart transplantation (bridge to transplantation), and who have acute heart failure and whose myocardial function is expected to return to normal (bridge to recovery). Although this therapy improves the mortality and quality of life among patients with heart failure, the devices also carry risk of multiple complications. This article discusses the acute and long-term complications of ventricular assist devices.

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.

Improved survival and decreasing incidence of adverse events with the HeartMate II left ventricular assist device as bridge-to-transplant therapy

BACKGROUND

Pulsatile left ventricular assist devices (LVADs) are effective as bridge-to-transplant therapy, but they are limited by their large size and lack of durability. Smaller, more durable, continuous flow devices such as the HeartMate II LVAD are increasingly being used. The aim of this study is to report our single-center experience with this device as bridge-to-transplant therapy.

METHODS

Overall, 47 patients received HeartMate II LVADs at our center from June 2005 to July 2007; 32 as bridge to transplant, 7 as destination therapy, and 8 as exchange therapy for a failed HeartMate XVE. We reviewed our experience with the device as bridge-to-transplant therapy and report on patient survival and adverse events.

RESULTS

The mean age of the bridge-to-transplant patients was 50.75 +/- 13.78 years; 10 (31.3%) were female. The cause of the underlying disease was ischemic in 18 patients (56.3%), idiopathic in 11 (34.4%), myocarditis in 1 (3.1%), postpartum cardiomyopathy in 1 (3.1%), and congenital heart disease in 1 (3.1%). The mean duration of HeartMate II support was 193.2 +/- 139.9 days. At 30 days after HeartMate II placement, the patient survival was 96.9% by Kaplan-Meier analysis; at 6 months (alive or transplanted), 86.9%. Major adverse events included bleeding requiring reexploration in 5 patients (15.6%), right ventricular failure requiring right ventricular assist device support in 2 (6.3%), LVAD-related infections in 4 (12.5%), neurologic or thromboembolic events in 2 (6.3%), and gastrointestinal bleeding in 5 (15.6%). We noted one serious device malfunction (3.1%) resulting in the patient's death; in addition, 2 patients experienced pump thrombosis (6.3%).

CONCLUSIONS

Despite morbidity, use of the HeartMate II LVAD as bridge-to-transplant therapy is associated with excellent survival and low mortality rates. We found a marked decrease in morbidity related to right ventricular failure, to device-related infections, and to thromboembolic events. However, the requirements for anticoagulation therapy may be associated with increased mediastinal and gastrointestinal bleeding. Strategies to optimize anticoagulation therapy may further improve results for these critically ill patients.

Low thromboembolic risk for patients with the Heartmate II left ventricular assist device

OBJECTIVE

Thromboembolic events can occur in up to 20% of patients with a left ventricular assist device. The aggressive use of anticoagulation with newer continuous-flow devices has potentially increased the risk of postoperative bleeding. The predecessor of the HeartMate II left ventricular assist device, the HeartMate XVE (Thoratec Corp, Pleasanton, Calif), was associated with an extremely low thromboembolic risk, even without anticoagulation, because of its unique textured surfaces. Even though several areas of the HeartMate II are textured, a protocol was adopted for this new axial flow pump requiring long-term anticoagulation with warfarin. In our study, we investigated whether the HeartMate II left ventricular assist device is associated with a similarly low thromboembolic risk as the HeartMate XVE.

METHODS

At our institution, 45 patients (mean age, 57.24 +/- 14.2 years) underwent implantation of the HeartMate II; 30 underwent bridge-to-transplantation therapy, 7 underwent destination therapy, and 8 underwent left ventricular assist device exchange for a failed XVE left ventricular assist device. Total duration of HeartMate II support was 352.13 patient-months (mean duration, 7.2 +/- 5.2 months). All 45 patients were treated postoperatively with warfarin and aspirin. We recorded use of these 2 medications and monthly international normalized ratios. Prospectively, we also monitored patients for any clinical thromboembolic events and for pump thrombus.

RESULTS

Of our 45 study patients, 41 had a mean international normalized ratio of less than 2.0; of those 41 patients, 21 had a mean international normalized ratio of less than 1.6. Because of recurrent gastrointestinal bleeding episodes, 7 patients discontinued warfarin for a total duration of 39.1 patient-months. During the entire period of HeartMate II support, we noted 1 thromboembolic event. In addition, another patient had a suspected left ventricular assist device pump thrombus that resolved with a high-intensity heparin anticoagulation protocol (international normalized ratio, 1.3).

CONCLUSIONS

Our preliminary single-center analysis suggests that the HeartMate II is associated with an extremely low thromboembolic risk and with less stringent requirements for anticoagulation. Selected patients at high risk for bleeding can be safely followed with either no or extremely low anticoagulation requirements for prolonged periods.

An automated communication system in a contact registry for persons with rare diseases: scalable tools for identifying and recruiting clinical research participants

OBJECTIVES

Strategies for study recruitment are useful in clinical research network settings. We describe a registry of individuals who have self-identified with one of a multiplicity of rare diseases, and who express a willingness to be contacted regarding possible enrollment in clinical research studies. We evaluate this registry and supporting tools in terms of registry enrollment and impact on participation rates in advertised clinical research studies.

METHODS

A web-based automated system generates periodic and customized communications to notify registrants of relevant studies in the NIH Rare Diseases Clinical Research Network (RDCRN). The majority of these communications are sent by email. We compare the characteristics of those enrolled in the registry to the characteristics of participants enrolled in sampled RDCRN studies in order to estimate the impact of the registry on study participation in the network.

RESULTS

The registry currently contains over 4000 registrants, representing 40 rare diseases. Estimates of study participation range from 6-27% for all enrollees. Study participation rates for some disease areas are over 40% when considering only contact registry enrollees who live within 100 mi of a clinical research study site.

CONCLUSIONS

Automated notifications can facilitate consistent, customized, and timely communication of relevant protocol information to potential research subjects. Our registry and supporting communication tools demonstrate a significant positive impact on study participation rates in our network. The use of the internet and automated notifications make the system scalable to support many protocols and registrants.

Assisting the failing heart

Anesthesiologists increasingly encounter patients who have a spectrum of heart failure ranging from stable chronic heart failure to acute heart failure to cardiogenic shock. Improved medical therapy has increased the survival of patients who have chronic heart failure but not of patients who have acute heart failure. New surgical techniques and mechanical devices may offer alternatives to certain patients who have refractory heart failure This article provides an overview of established and newer pharmacologic and nonpharmacologic therapies and surgical interventions to manage patients who have heart failure, including the perioperative management of heart transplantation and ventricular assist devices.

Stem cell therapy trials: a call for standardization

There are currently 25 new clinical cellular therapy trials in progress for cardiovascular disease in the US, and a similar number ongoing in Europe. The lack of standardization in cell isolation, preparation, storage, and time and localization of delivery, present clear hurdles to this growing field. This emphasizes the need for an organized task force to work closely with the FDA to agree upon standardized methods with the end result being improvements in patient care and enhanced knowledge in the field.

The right ventricular failure risk score a pre-operative tool for assessing the risk of right ventricular failure in left ventricular assist device candidates

OBJECTIVES

This study sought to develop a model that estimates the post-operative risk of right ventricular (RV) failure in left ventricular assist device (LVAD) candidates.

BACKGROUND

Right ventricular failure after LVAD surgery is associated with increased morbidity and mortality, but identifying LVAD candidates at risk for RV failure remains difficult.

METHODS

A prospectively collected LVAD database was evaluated for pre-operative clinical, laboratory, echocardiographic, and hemodynamic predictors of RV failure. Right ventricular failure was defined as the need for post-operative intravenous inotrope support for >14 days, inhaled nitric oxide for > or =48 h, right-sided circulatory support, or hospital discharge on an inotrope. An RV failure risk score (RVFRS) was created from multivariable logistic regression model coefficients, and a receiver-operating characteristic curve of the score was generated.

RESULTS

Of 197 LVADs implanted, 68 (35%) were complicated by post-operative RV failure. A vasopressor requirement (4 points), aspartate aminotransferase > or =80 IU/l (2 points), bilirubin > or =2.0 mg/dl (2.5 points), and creatinine > or =2.3 mg/dl (3 points) were independent predictors of RV failure. The odds ratio for RV failure for patients with an RVFRS < or =3.0, 4.0 to 5.0, and > or =5.5 were 0.49 (95% confidence interval [CI] 0.37 to 0.64), 2.8 (95% CI 1.4 to 5.9), and 7.6 (95% CI 3.4 to 17.1), respectively, and 180-day survivals were 90 +/- 3%, 80 +/- 8%, and 66 +/- 9%, respectively (log rank for linear trend p = 0.0045). The area under the receiver-operating characteristic curve for the RVFRS (0.73 +/- 0.04) was superior to that of other commonly used predictors of RV failure (all p < 0.05).

CONCLUSIONS

The RVFRS, composed of routinely collected, noninvasive pre-operative clinical data, effectively stratifies the risk of RV failure and death after LVAD implantation.

Initial clinical experience with the VentrAssist left ventricular assist device: the pilot trial

BACKGROUND

The VentrAssist (VA) is a novel, continuous flow left ventricular assist device (LVAD). The purpose of this trial was to investigate the safety and efficacy of the VA in elderly patients with end-stage heart failure.

METHODS

In this prospective trial, patients requiring circulatory support either as destination therapy (DT) or as a bridge to transplant (BTT) were implanted with a VA device.

RESULTS

Between June 2003 and August 2006, 9 elderly patients (mean age 65 years) were implanted. The median support time was 454 (range 73 to 977) days for the DT and 35 (range 26 to 508) days for the BTT cohort. All patients survived implantation; 30-day mortality was 22% (n = 2). The adverse event profile was encouraging, with no embolic neurologic events and minimal sepsis. Cumulative trial support time was 7.3 patient-years.

CONCLUSIONS

The VentrAssist shows promise as a safe and reliable "third-generation" VAD. Having demonstrated potential as a DT and prolonged BTT device, extended clinical trials are warranted.

Mechanical circulatory support devices for acute heart failure syndromes: considerations for clinical trial design

Mechanical circulatory support (MCS) devices are a guideline-recommended treatment option for a small subset of advanced heart failure patients. MCS has the potential to become more prominent in the management of Acute Heart Failure Syndromes (AHFS) as device technology advances and as clinical trials consistently discover neutral or harmful effects with pharmacologic therapies hypothesized to be beneficial in this population. While it is now possible to identify AHFS patients who are at high risk of death, the therapeutic options available to improve their long-term outcomes are limited. MCS therapy in this population offers a "bridge to recovery" strategy; these patients may have viable myocardium that responds favorably to the influence of MCS on neurohormones, cytokines, and/or reverse remodeling. Patients at high risk for mortality who have a substantial likelihood of benefiting from MCS can be easily identified using standard clinical criteria developed from large observational databases. MCS technology is rapidly evolving, and risks related to implantation are declining. It is evident that rigorous clinical trial testing of the potential risks, benefits, and economic implications of MCS in patients with AHFS will need to be conducted before the "routine" application of this aggressive therapy. This paper examines the rationale for conducting trials of MCS devices in patients with AHFS, and it explores considerations for patient selection and appropriate endpoints. This manuscript was generated from discussions on this issue during the third international meeting of the International Working Group on AHFS held in Washington, DC, April 8-9, 2006.