Multicenter clinical evaluation of the HeartMate 1000 IP left ventricular assist device

Percutaneous ventricular assist devices: new deus ex machina?

The development of ventricular assist devices has broadened the means with which one can treat acute heart failure. Percutaneous ventricular assist devices (pVAD) have risen from recent technological advances. They are smaller, easier, and faster to implant, all important qualities in the setting of acute heart failure. The present paper briefly describes the functioning and assets of the most common devices used today. It gives an overview of the current evidence and indications for left ventricular assist device use in cardiogenic shock and high-risk percutaneous coronary intervention. Finally, extracorporeal life support devices are dealt with in the setting of hemodynamic support.

A review of clinical ventricular assist devices

Given the limited availability of donor hearts, ventricular assist device (VAD) therapy is fast becoming an accepted alternative treatment strategy to treat end-stage heart failure. The field of mechanical ventricular assistance is littered with novel and unique ideas either based on volume displacement or rotary pump technology, which aim to sufficiently restore cardiac output. However, only a select few have made the transition to the clinical arena. Clinical implants were initially dominated by the FDA approved volume displacement Thoratec HeartMate I, IVAD, and PVAD, whilst Berlin Heart's EXCOR, and Abiomed's BVS5000 and AB5000 offered suitable alternatives. However, limitations associated with an inherently large size and reduced lifetime of these devices stimulated the development and subsequent implantation of rotary blood pump (RBP) technology. Almost all of the reviewed RBPs are clinically available in Europe, whilst many are still undergoing clinical trial in the USA. Thoratec's HeartMate II is currently the only rotary device approved by the FDA, and has supported the highest number of patients to date. This pump is joined by MicroMed Cardiovascular's Heart Assist 5 Adult VAD, Jarvik Heart's Jarvik 2000 FlowMaker and Berlin Heart's InCOR as the axial flow devices under investigation in the USA. More recently developed radial flow devices such as WorldHeart's Levacor, Terumo's DuraHeart, and HeartWare's HVAD are increasing in their clinical trial patient numbers. Finally CircuLite's Synergy and Abiomed's Impella are two mixed flow type devices designed to offer partial cardiac support to less sick patients. This review provides a brief overview of the volume displacement and rotary devices which are either clinically available, or undergoing the advanced stages of human clinical trials.

In vivo biocompatibility evaluation of a new resilient, hard-carbon, thin-film coating for ventricular assist devices

The purpose of this study was to evaluate in vivo the biocompatibility of BioMedFlex (BMF), a new resilient, hard-carbon, thin-film coating, as a blood journal bearing material in Cleveland Heart's (Charlotte, NC, USA) continuous-flow right and left ventricular assist devices (RVADs and LVADs). BMF was applied to RVAD rotating assemblies or both rotating and stator assemblies in three chronic bovine studies. In one case, an LVAD with a BMF-coated stator was also implanted. Cases 1 and 3 were electively terminated at 18 and 29 days, respectively, with average measured pump flows of 4.9 L/min (RVAD) in Case 1 and 5.7 L/min (RVAD) plus 5.7 L/min (LVAD) in Case 3. Case 2 was terminated prematurely after 9 days because of sepsis. The sepsis, combined with running the pump at minimum speed (2000 rpm), presented a worst-case biocompatibility challenge. Postexplant evaluation of the blood-contacting journal bearing surfaces showed no biologic deposition in any of the four pumps. Thrombus inside the RVAD inlet cannula in Case 3 is believed to be the origin of a nonadherent thrombus wrapped around one of the primary impeller blades. In conclusion, we demonstrated that BMF coatings can provide good biocompatibility in the journal bearing for ventricular assist devices.

Percutaneous left ventricular assist devices during cardiogenic shock and high-risk percutaneous coronary interventions

Left ventricular assist devices were developed to support the function of a failing left ventricle. Owing to recent technological improvements, ventricular assist devices can be placed by percutaneous implantation techniques, which offer the advantage of fast implantation in the setting of acute left ventricular failure. This article reviews the growing evidence supporting the clinical use of left ventricular assist devices. Specifically, we discuss the use of left ventricular assist devices in patients with cardiogenic shock, in patients with acute ST-elevation myocardial infarction without shock, and during high-risk percutaneous coronary interventions.

Hematologic effects of continuous flow left ventricular assist devices

The extent of hematologic effects of the new continuous flow left ventricular assist devices (CF-LVAD) has not been studied. Recent clinical studies have demonstrated that hemolysis and thrombosis are not common during CF-LVAD support, however, the incidence of bleeding remains a concern. The rate of postoperative bleeding is similar to that of the prior generation pulsatile LVAD, but gastrointestinal bleeding due to angiodysplasia and arteriovenous malformations is more common and appears to be related to the blood flow rheology of these devices. New evidence suggests that acquired von Willebrand's disease develops in some patients due to the reduction in high molecular weight (HMW) multimers of von Willebrand's factor (vWF). Similar to acquired von Willebrand's disease seen in patients with aortic stenosis, the shear stress of the CF-LVAD may cause proteolysis of the HMW multimers of vWF. In addition to acquired von Willebrand's disease, there is activation of the fibrinolytic system and a loss of platelet numbers and function during CF-LVAD support. The hematologic responses during CF-LVAD support are constantly changing, and antiplatelet therapy may need to be adjusted accordingly. Considerable research is needed to better define the complex hematologic effects during CF-LVAD support. Screening of patients for angiodysplasia and von Willebrand's disease before CF-LVAD implant may allow for effective preemptive treatment. Because bleeding causes significant morbidity for this population, more effective treatment strategies need to be developed.

Regionalized Approach to Emergency Medical Services Training for the Care of Patients with Mechanical Assist Devices

Advances in mechanical circulatory assist device technology have allowed dozens of patients with different types of devices to live in any community in the United States. Some of the newer devices pump blood continuously, resulting in patients without pulses. The mechanical circulatory assist device teams and emergency medical services providers in the mid-Atlantic region wondered how best to prepare the community to respond appropriately to emergencies in patients with these mechanical devices.

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.

Structural performance and hydrodynamic resistance of a new silicone auricular cannula tip

Development of a new generation pneumatic of Ventricular Assist Device (VAD) required the design of cannulae to improve its optimal performance. In this case, a relevant restrictive design parameter was the material of the cannulae. Silicone was the best choice in a hemocompatible focus, but this is a material with very low stiffness. If the material is flexible, the most important parameter that affects either the structural performance or the hydrodynamic resistance is the amount of side holes on the cannulae tip, known as the effective drainage area. In order to obtain an estimation of the structural performance and of the hydrodynamic resistance, a study based on two independent analysis is needed: the structural and the in vitro drop pressure analysis. Structural analyses based on computer simulations were made in order to estimate the bending behavior of four silicone prototypes of cannulae tips. On the other hand, experiments under hydrostatic conditions were made to test and compare the pressure loss and flow rate relationship. A cannula tip with six side holes showed good hydrostatic performance, having almost the same as the one with nine side holes. Plus, it presented and a satisfactory structural behavior. This study assisted the design process of an auricular silicone cannula, recommending the use of cannulae with six side holes for a specific VAD.

Trileaflet valve hydrodynamic resistance assessment

Valve hydrodynamic performance is usually assessed by effective orifice area, transvalvular resistance, regurgitation and blood damage effect. Some studies suggest effects in effective orifice area due to cardiovascular resistance, compliance and angle position of the valve. We suppose that silicone rubber valves under study have a good performance under different cardiovascular resistance conditions. Two in vitro experiments were made to test this hypothesis under constant and pulsatile flow rate. Transvalvular gradient pressure, transvalvular resistance, Gorling effective orifice area, effective orifice area in the ascending aorta and Reynolds numbers were estimated in both flow rates. Results suggest that cardiovascular resistance has no significant effect for this kind of valves, however resistance effect is observed in pumping pressure. Small transvalvular resistance and transvalvular pressure gradients were found. Gorlin effective orifice areas greater than 0.3 cm(2) have not viscosity effect. P-value 0.001 was found between Gorlin effective orifice area under constant and pulsatile flow rate.

Inhaled NO as a therapeutic agent

In 1991, Frostell and colleagues reported that breathing low concentrations of nitric oxide (NO) decreased pulmonary artery pressure (PAP) in awake lambs with experimental pulmonary hypertension (PH) [Frostell C, Fratacci MD, Wain JC, Jones R, Zapol WM. Inhaled nitric oxide. A selective pulmonary vasodilator reversing hypoxic pulmonary vasoconstriction. Circulation 1991;83:2038-47]. Subsequently, efforts of multiple research groups studying animals and patients led to approval of inhaled NO by the US Food and Drug Administration in 1999 and the European Medicine Evaluation Agency and European Commission in 2001. Inhaled NO is currently indicated for the treatment of term and near-term neonates with hypoxemia and PH. Since regulatory approval, several studies have suggested that NO inhalation can prevent chronic lung disease in premature infants. In addition, unanticipated systemic effects of inhaled NO may lead to treatments for a variety of disorders including ischemia-reperfusion injury. This review summarizes the pharmacology and physiological effects of breathing NO. The application of inhaled NO to hypoxemic neonates with PH is discussed including recent studies exploring the use of inhaled NO to prevent bronchopulmonary dysplasia in premature infants. This review also highlights the application of inhaled NO to treat adults with cardiopulmonary disease, strategies to augment the efficacy of inhaled NO, and potential applications of the systemic effects of the gas.

Vascular Thrombosis During Support With Continuous Flow Ventricular Assist Devices: Correlation With Computerized Flow Simulations

Continuous flow pumps are increasingly used to treat severe heart failure. These pumps alter flow physiology by lowering pulsatility in the arterial circulation. In patients with peripheral stenosis, continuous flow pumps may lead to thrombosis of peripheral vessels, possibly predisposing to vascular thrombosis in areas of non-flow-limiting stenosis. The authors performed a computerized flow modeling simulation to analyze the effects of altered hemodynamics in a stenotic area. Drawing on previous clinical experience, we modeled a stenotic area in the common carotid artery. Computerized flow modeling revealed blood stagnation zones with low shear stress and velocity adjacent to the stenotic area during nonpulsatile flow. Such stagnation was not present during pulsatile flow. These results indicate a mechanism by which altered physiologic flow may accelerate occlusion of arterial conduits in patients with preexisting stenosis. This finding may be important for patients with continuous flow devices who have peripheral vascular disease; therefore, further study is warranted.

Experimental and Computer-Based Performance Analysis of Two Elastomer VAD Valve Designs

The development of a new generation pneumatic Ventricular Assist Device (VAD) required the design of valves for the optimization of its performance. Experiments and computer-based simulations under hydrostatic conditions were analyzed in order to test and compare two low-cost elastomer valve designs. The trileaflet valve design showed a superior hydrostatic performance, having almost a ratio of 1:2 hydraulic resistance than the bileaflet valve design in agreement with both, the experimental and the simulation evidences. This study will address the use of a trileaflet valve designs in the future VAD redesign.

Evaluation of the clinical effectiveness of the Ventricular Assist Device Program in the United Kingdom (EVAD UK)

BACKGROUND

The UK Government funds ventricular assist device (VAD) implantation as bridge to transplantation (BTT) at three centers. Results from this program have not been published.

METHODS

All 70 VAD implants for BTT, 71 inotrope-dependent and 179 non-VAD transplant candidates, accepted for transplantation between April 2002 and December 2004, were prospectively monitored for survival to transplantation, survival overall and quality of life.

RESULTS

Of the 70 VAD patients, 31 (44%) survived to heart transplantation, 4 (6%) were bridged to recovery and 5 remained on support at the end of the study. Thirty patients (43%) died while on support. Overall survival from VAD implant was 52% at 1 year. Ten percent of non-VAD inotrope-dependent patients and 9% of routine transplant candidates died while on the waiting list. For transplant recipients, 12-month post-operative survival was 84%, 85% and 84%, respectively, for VAD, inotrope-dependent and routine transplant candidates. VAD and non-VAD patients had similar post-transplant adverse event rates.

CONCLUSIONS

There was a role for VAD bridge to transplant for selected patients in the UK, despite the availability of an effective urgent transplant list. VAD patients who underwent transplantation had survival rates similar to other transplant candidates.

Designs for Mechanical Circulatory Support Device Studies

BACKGROUND

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

METHODS AND RESULTS

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

CONCLUSIONS

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

Psychiatric problems of heart transplant candidates with left ventricular assist devices

Most heart transplant candidates are equipped with left ventricular assist devices (LVADs). LVAD therapy is associated with characteristic psychiatric and psychosocial problems. To investigate the mental states of heart transplant candidates, psychiatric diagnosis, psychological or behavioral problems, and the need for treatment were evaluated around the time of registration to the waiting list and during follow-up. Saitama Medical University Hospital has been designated a hospital for heart transplantation since October 2002. The subjects were 14 heart transplant candidates (9 male candidates and 5 female candidates, mean age 29 years) at the hospital from September 1997 to October 2005. These 14 candidates were equipped with LVADs. The waiting periods on LVAD support were from 119 days to 1028 days, and the average waiting period was 313 days. Six candidates among the 14 had more than one DSM-IV diagnosis. Seven candidates were diagnosed with adjustment disorder, which was the most frequent diagnosis. Three candidates had depressive disorder, one had psychotic disorder, and one had dissociative disorder. Three candidates had acute cognitive dysfunction (delirium) due to their general medical condition. All three had other disorders with mainly psychological elements. Nine candidates (64%) were diagnosed with disorders with mainly psychological elements. Antipsychotics were used for the candidates in psychotic states and with delirium, and there was a need for crisis intervention. Antidepressants and antianxiety drugs were used for the candidates with depressive disorder; they needed intensive observation. Four candidates (28%) needed some attention and some antianxiety drugs or hypnotics. Psychiatric interventions were not necessary in five candidates (36%).

Omental Transposition Flap for Salvage of Ventricular Assist Devices

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Left ventricular assist system through the left ventricle for acute myocardial infarction: report of a case

A 49-year-old man, who had suffered from acute myocardial infarction due to left main trunk occlusion, developed cardiogenic shock and was successfully treated with an implantation of a left ventricular assist system with left ventricular apical drainage. At present he is awaiting a heart transplant at approximately 485 days since the operation. The timely application of a left ventricular assist system before the development of multiple organ failure is thus considered to be effective for patients demonstrating acute myocardial infarction with cardiogenic shock.

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.

Percutaneous Left Ventricular Support Devices

Patients undergoing percutaneous coronary intervention (PCI) who have severely compromised left ventricular systolic function and complex coronary lesions including multivessel disease, left main disease, or bypass graft disease are at higher risk of adverse outcomes from hemodynamic collapse. The TandemHeart percutaneous left ventricular assist device and the Impella Recover LP 2.5 System may provide rapid circulatory support in high-risk PCI patients and in those who have cardiogenic shock. Identification of patients who are at high risk for severe hemodynamic compromise and most likely to benefit from mechanical circulatory support is crucial to derive the most benefit from this therapy. Multicenter randomized clinical trials are needed to clearly define the role of these two devices in providing circulatory support in a variety of clinical settings.

Clinical and cost-effectiveness of left ventricular assist devices as a bridge to heart transplantation for people with end-stage heart failure: a systematic review and economic evaluation

AIMS

To evaluate the clinical and cost-effectiveness of left ventricular (LV) assist devices (LVADs) as a bridge to transplant (BTT) for people with end-stage heart failure (ESHF) through a systematic review and economic evaluation.

METHODS AND RESULTS

The systematic review and economic evaluation was conducted according to internationally recognized methods. The search strategy identified systematic reviews, randomized controlled trials, quasi-experimental studies, and observational studies evaluating the effects of LVADs on survival, functional capacity, and quality of life. Cost-effectiveness was assessed through a 5-year decision analytic model to estimate the incremental cost-effectiveness ratio of LVADs compared with usual care. Despite the poor methodological quality of the 18 studies included, LVADs appear beneficial improving survival, functional status, and quality of life. Adverse events are a serious concern. The economic evaluation showed that LVADs had a cost per quality adjusted life year of pound 65,242 (95% confidence interval pound 34,194-364,564). Sensitivity analysis showed that post-heart transplant survival gains, pre-heart transplant patient utility, and one-off costs associated with implantation determine cost-effectiveness.

CONCLUSION

Although LVADs appear clinically effective as a BTT for people with ESHF, it is unlikely that they will be cost-effective unless costs decrease or the benefits of their use increase.

Hydrodynamic effects of the partial opening of a trileaflet valve

Manufacturing process of medical grade silicon rubber trileaflet valves for VADs could propitiate important leaflet thickness variations which could result in partial opening of the valve and affect its hydrodynamic performance. The leaflets of a total of 10 valves were measured to assess its thickness variability. Two experiments were performed to asses the impact of the leaflets thickness variation under hypothetical situations. The first experiment was divided into three hypothetical cases. In each case either none, one or two leaflets of different valves were mechanically blocked, resembling possible critical working circumstances. The second experiment was intended to know how the variation on the leaflets thickness affects the hydrodynamic performance of the valves. The results demonstrated a significant variation on the leaflets thickness was found. As for the first experiment, a small variation on the hydrodynamic performance was found above 4 L/min flow rates and a slightly higher energy loss was found in one of the cases. As for the second experiment, the results showed that the variation of the leaflet thickness does not affect the general hydrodynamic performance of the valves. No relationship between the thickness variability and the hydrostatic performance of the valves was found.

Heart Failure Elevates Serum Levels of Cibenzoline in Arrhythmic Patients

BACKGROUND

Cibenzoline dosing is generally based on renal function, but serum concentrations might be greater than the expected therapeutic levels when standard oral dosing is used. Because heart failure might modify cibenzoline pharmacokinetics, the difference in cibenzoline pharmacokinetics between patients with and without heart failure was evaluated.

METHODS AND RESULTS

The study enrolled 368 patients (233 men, 135 women) that had been hospitalized and received cibenzoline therapy at the National Cardiovascular Center from January 2001 to May 2005. There were 89 patients with heart failure (51 men, 38 women) and 279 patients without heart failure (182 men, 97 women). They had therapeutic drug monitoring > or = 3 days after the beginning of treatment with cibenzoline. Brain natriuretic peptide (BNP) was measured in 81 patients (50 men, 31 women) concurrently with therapeutic drug monitoring of cibenzoline. The difference in serum cibenzoline concentration/(dose/weight) (C/D) values between patients with and without heart failure was analyzed using analysis of covariance (ANCOVA) with creatinine clearance (Ccr) serving as the covariate. The effects of dose/weight and the log-transformed BNP (log-BNP) values on serum cibenzoline concentrations were also assessed using ANCOVA. There were 135 and 361 measurements of serum cibenzoline concentration in patients with and without heart failure, respectively. Pearson's correlation coefficient analyses in the patients with and without heart failure revealed that the C/D values were significantly correlated with Ccr (with heart failure, y = -0.837x + 169, r = -0.211, p = 0.014; without heart failure, y = -0.789x + 132, r = -0.393, p < 0.001), and the ANCOVA model indicated that C/D values were significantly higher in patients with heart failure than without heart failure. The ANCOVA model also showed that dose/weight, Ccr and the log-BNP value were significant factors.

CONCLUSIONS

The selection of a cibenzoline dose based only on renal function may increase the risk of toxicity in patients with heart failure. Cardiac function should be taken into account in cibenzoline dosing. The log-BNP may be a useful index for predicting serum cibenzoline concentrations.

Gastrointestinal bleeding from arteriovenous malformations in patients supported by the Jarvik 2000 axial-flow left ventricular assist device

The long-term effects of axial-flow mechanical circulatory support in humans are unclear. We report 3 cases of chronic gastrointestinal bleeding after implantation of a Jarvik 2000 axial-flow left ventricular assist device. The bleeding was refractory to aggressive management and in 2 cases resolved only after orthotopic cardiac transplantation.

Bridge to heart transplantation with the HeartMate device in Gothenburg, Sweden

BACKGROUND

Patients rapidly deteriorating while waiting for heart transplantation present a major problem. Our strategy for this entity is the HeartMate left ventricular assist device (LVAD) VELVAS, an electrically driven implantable LVAD. Herein we report our initial experience.

METHODS

The medical records of all the patients who received HeartMate LVAS at our institution were reviewed.

RESULTS

From January 1997 through May 2004, 19 patients received a HeartMate. The mean age was 39 (15 to 61) years and 84% were men. The diagnoses were: dilated cardiomyopathy (n = 8), ischemic heart disease (n = 6), myocarditis (n = 3), congenital heart disease (n = 1), and hypertrophic cardiomyopathy (n = 1). Mean time on LVAD was 113 (10 to 353) days. Ten patients were discharged from the hospital to their homes awaiting transplant or recovery. Three patients showed recovery of heart function and were subsequently weaned from mechanical support. Thirteen patients underwent heart transplantation. Three patients died during LVAD treatment. Major adverse events occurred in nine patients, including severe right heart failure (n = 3), severe bleeding (n = 3), stroke (n = 1), hepatic failure (n = 1), and septicemia (n = 2). Nine of the 13 transplanted patients are alive and well today.

CONCLUSION

HeartMate LVAS is a valuable option for patients rapidly deteriorating while awaiting a heart transplant. Our results are comparable with those reported from larger centers.

Similar left and right ventricular sarcomere structure after support with a left ventricular assist device suggests the utility of right ventricular biopsies to monitor left ventricular reverse remodeling

BACKGROUND

To evaluate whether the morphology of the contractile filaments in cardiomyocytes of patients with end-stage heart failure, treated with a left ventricular assist device (LVAD), is identical in the left- and right ventricle (LV, RV) and in the interventricular septum (IVS) and can be monitored by biopsies taken with a bioptome. The application of an LVAD as a bridge to recovery of cardiac function requires monitoring of myocyte recovery. The use of RV biopsies for this purpose might be feasible, if morphologic findings in the RV coincide with those in the LV.

METHODS AND RESULTS

At the time of heart transplantation, myocardial biopsies of LV, RV and IVS from 13 patients after LVAD support were compared using immunohistochemistry with monoclonal antibodies against contractile proteins. Additionally, in five of these patients, small biopsies obtained with a diagnostic bioptome were compared with large transmural biopsies of the same region. Hemodynamic monitoring was performed when the patients were fully recovered from the implantation, to rule out persistent RV failure. The staining pattern of actin, myosin, tropomyosin, troponin T and C was identical in the biopsies of LV, RV and IVS. Small biopsies taken with a bioptome appeared to be representative for the larger biopsies. Hemodynamic monitoring showed absence of RV failure in our study group.

CONCLUSION

In the absence of RV failure, morphology of the contractile myofilaments after LVAD support for 215+/-143 days is identical in LV, RV and IVS. This may allow monitoring of the possible occurrence of LV reverse remodeling by RV biopsies.