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/

A modified Glenn shunt reduces venous congestion during acute right ventricular failure due to pulmonary banding: a randomized experimental study

OBJECTIVES

Right ventricular failure after left ventricular assist device implantation is a serious complication with high rates of mortality and morbidity. It has been demonstrated in experimental settings that volume exclusion of the right ventricle with a modified Glenn shunt can improve haemodynamics during ischaemic right ventricular failure. However, the concept of a modified Glenn shunt is dependent on a normal pulmonary vascular resistance, which can limit its use in some patients. The aim of this study was to explore the effects of volume exclusion with a modified Glenn shunt during right ventricular failure due to pulmonary banding, and to study the alterations in genetic expression in the right ventricle due to pressure and volume overload.

METHODS

Experimental right ventricular failure was induced in pigs (n = 11) through 2 h of pulmonary banding. The pigs were randomized to either treatment with a modified Glenn shunt and pulmonary banding (n = 6) or solely pulmonary banding (n = 5) as a control group. Haemodynamic measurements, blood samples and right ventricular biopsies for genetic analysis were sampled at baseline, at right ventricular failure (i.e. 2 h of pulmonary banding) and 1 h post-right ventricular failure in both groups.

RESULTS

Right atrial pressure increased from 10 mmHg (9.0-12) to 18 mmHg (16-22) (P < 0.01) and the right ventricular pressure from 31 mmHg (26-35) to 57 mmHg (49-61) (P < 0.01) after pulmonary banding. Subsequent treatment with the modified Glenn shunt resulted in a decrease in right atrial pressure to 13 mmHg (11-14) (P = 0.03). In the control group, right atrial pressure was unchanged at 19 mmHg (16-20) (P = 0.18). At right heart failure, there was an up-regulation of genes associated with heart failure, inflammation, angiogenesis, negative regulation of cell death and proliferation.

CONCLUSIONS

Volume exclusion with a modified Glenn shunt during right ventricular failure reduced venous congestion compared with the control group. The state of right heart failure was verified through genetic expressional changes.

Exercise limitation following transplantation

Organ transplantation is one of the medical miracles or the 20th century. It has the capacity to substantially improve exercise performance and quality of life in patients who are severely limited with chronic organ failure. We focus on the most commonly performed solid-organ transplants and describe peak exercise performance following recovery from transplantation. Across all of the common transplants, evaluated significant reduction in VO2peak is seen (typically renal and liver 65%-80% with heart and/or lung 50%-60% of predicted). Those with the lowest VO2peak pretransplant have the lowest VO2peak posttransplant. Overall very few patients have a VO2peak in the normal range. Investigation of the cause of the reduction of VO2peak has identified many factors pre- and posttransplant that may contribute. These include organ-specific factors in the otherwise well-functioning allograft (e.g., chronotropic incompetence in heart transplantation) as well as allograft dysfunction itself (e.g., chronic lung allograft dysfunction). However, looking across all transplants, a pattern emerges. A low muscle mass with qualitative change in large exercising skeletal muscle groups is seen pretransplant. Many factor posttransplant aggravate these changes or prevent them recovering, especially calcineurin antagonist drugs which are key immunosuppressing agents. This results in the reduction of VO2peak despite restoration of near normal function of the initially failing organ system. As such organ transplantation has provided an experiment of nature that has focused our attention on an important confounder of chronic organ failure-skeletal muscle dysfunction.

Continuous flow left ventricular assist device implant significantly improves pulmonary hypertension, right ventricular contractility, and tricuspid valve competence

BACKGROUND

Continuous flow left ventricular assist devices (CF LVAD) are being implanted with increasing frequency for end-stage heart failure. At the time of LVAD implant, a large proportion of patients have pulmonary hypertension, right ventricular (RV) dysfunction, and tricuspid regurgitation (TR). RV dysfunction and TR can exacerbate renal dysfunction, hepatic dysfunction, coagulopathy, edema, and even prohibit isolated LVAD implant. Repairing TR mandates increased cardiopulmonary bypass time and bicaval cannulation, which should be reserved for the time of orthotopic heart transplantation. We hypothesized that CF LVAD implant would improve pulmonary artery pressures, enhance RV function, and minimize TR, obviating need for surgical tricuspid repair.

METHODS

One hundred fourteen continuous flow LVADs implanted from 2005 through 2011 at a single center, with medical management of functional TR, were retrospectively analyzed. Pulmonary artery pressures were measured immediately prior to and following LVAD implant. RV function and TR were graded according to standard echocardiographic criteria, prior to, immediately following, and long-term following LVAD.

RESULTS

There was a significant improvement in post-VAD mean pulmonary arterial pressures (26.6 ± 4.9 vs. 30.2 ± 7.4 mmHg, p = 0.008) with equivalent loading pressures (CVP = 12.0 ± 4.0 vs. 12.1 ± 5.1 p = NS). RV function significantly improved, as noted by right ventricular stroke work index (7.04 ± 2.60 vs. 6.05 ± 2.54, p = 0.02). There was an immediate improvement in TR grade and RV function following LVAD implant, which was sustained long term.

CONCLUSION

Continuous flow LVAD implant improves pulmonary hypertension, RV function, and tricuspid regurgitation. TR may be managed nonoperatively during CF LVAD implant.

Load Dependency of Right Ventricular Performance Is a Major Factor to be Considered in Decision Making Before Ventricular Assist Device Implantation

Background—

Left ventricular assist devices (LVADs) provide better outcome than biventricular devices, but it is a challenge to predict the impact of LV mechanical unloading on postoperative right ventricular (RV) function preoperatively. We assessed the load dependency in RV performance before and after LVAD implantation aiming to improve preoperative decision making.

Methods and Results—

Laboratory, echocardiography, and right heart catheterization data collected from 205 patients before LVAD implantation were tested for relationship with postoperative RV function. Comparing patients with different time-course of RV function after LVAD implantation, we found significant differences ( P <0.01) in preoperative RV end-diastolic short-/long-axis and long-axis/length-area ratios, tricuspid annulus peak systolic velocity, RV peak longitudinal global systolic strain rate, systolic pressure gradient between RV and right atrium (Δ P RV−RA ), tricuspid regurgitation velocity-time integral, and pulmonary arterial pressure between patients with and without postoperative RV failure. High predictive values for postoperative RV failure were found for end-diastolic short-/long-axis ratio ≥0.6, tricuspid annulus peak systolic velocity <8 cm/s, and peak systolic longitudinal strain rate <0.6/s in patients with maximum Δ P RV−RA <35 mm Hg. These parameters also seemed predictive for RV failure in patients with tricuspid regurgitation grade >2 and pulmonary arterial pressure <50 mm Hg. End-diastolic short-/long-axis ratio <0.6, tricuspid annulus peak systolic velocity ≥8 cm/s, and peak systolic longitudinal strain rate ≥0.6 in patients with maximum Δ P RV−RA ≥35 mm Hg showed high predictive values for postoperative freedom from RV failure. The RV load adaptation index seemed particularly predictive for RV function after LVAD implantation.

Conclusions—

RV geometry and velocity of contraction before LVAD implantation become more predictive for postoperative RV function and can improve decision making before VAD implantation if preoperative RV pressure load and tricuspid regurgitation are also considered.

Predicting right ventricular failure in the modern, continuous flow left ventricular assist device era

BACKGROUND

In the era of destination continuous flow left ventricular assist devices (LVAD), the decision of whether a patient will tolerate isolated LVAD support or will need biventricular support (BIVAD) can be challenging. Incorrect decision making with delayed right ventricular (RV) assist device implantation results in increased morbidity and mortality. Continuous flow LVADs have been shown to decrease pulmonary hypertension and improve RV function. We undertook this study to determine predictors in the continuous flow LVAD era that identify patients who are candidates for isolated LVAD therapy as opposed to biventricular support.

METHODS

We reviewed demographic, hemodynamic, laboratory, and echocardiographic variables for 218 patients who underwent VAD implant from 2003 through 2011 (LVAD=167, BIVAD=51), during the era of continuous flow LVADs.

RESULTS

Fifty preoperative risk factors were compared between patients who were successfully managed with an LVAD and those who required a BIVAD. Seventeen variables demonstrated statistical significance by univariate analysis. Multivariable logistic regression analysis identified central venous pressure>15 mmHg (OR 2.0, "C"), severe RV dysfunction (OR 3.7, "R"), preoperative intubation (OR 4.3, "I"), severe tricuspid regurgitation (OR 4.1, "T"), heart rate>100 (OR 2.0, Tachycardia-"T")-CRITT as the major criteria predictive of the need for biventricular support. Utilizing these data, a highly sensitive and easy to use risk score for determining RV failure was generated that outperformed other established risk stratification tools.

CONCLUSIONS

We present a preoperative risk calculator to determine suitability of a patient for isolated LVAD support in the current continuous flow ventricular assist device era.

Advances and future directions for mechanical circulatory support

Although cardiac transplant remains the gold standard for the treatment of end-stage heart failure, limited donor organ availability and growing numbers of eligible recipients have increased the demand for alternative therapies. Limitations of first-generation left ventricular assist devices for long-term support of patients with end-stage disease have led to the development of newer second-generation and third-generation pumps, which are smaller, have fewer moving parts, and have shown improved durability, allowing for extended support. The HeartMate II (second generation) and HeartWare (third generation) are 2 devices that have shown great promise as potential alternatives to transplantation in select patients.

Postoperative right ventricular failure after left ventricular assist device placement is predicted by preoperative echocardiographic structural, hemodynamic, and functional parameters

BACKGROUND

Right ventricular failure (RVF) after left ventricular assist device (LVAD) implantation results in significant morbidity and mortality. Preoperative parameters from transthoracic echocardiography (TTE) that predict RVF after LVAD implantation might identify patients in need of temporary or permanent right ventricular (RV) mechanical or inotropic support.

METHODS AND RESULTS

Records of all patients who had preoperative TTE before implantation of a permanent LVAD at our institution from 2008 to 2011 were screened, and 55 patients (age 54 ± 16 years, 71% male) were included: 26 had LVAD implantation alone with no postoperative RVF, 16 had LVAD implantation alone but experienced postoperative RVF, and 13 had initial biventricular assist devices (BIVADs). The LVAD with RVF and BIVAD groups (RVF group) were pooled for comparison with the LVAD patients without RVF (No RVF group). RV fractional area change (RV FAC) was significantly lower in the RVF group versus the No RVF group (24% vs 30%; P = .04). Tricuspid annular plane systolic excursion was not different among the groups (1.6 cm vs 1.5 cm; P = .53). Estimated right atrial pressure (RAP) was significantly higher in the RVF group versus the No RVF group (11 mm Hg vs 8 mm Hg; P = .04). Left atrial volume (LAV) index was lower in patients with RVF versus No RVF (27 mL/m(2) vs 40 mL/m(2); P = .008). Combining RV FAC, estimated RAP, and LAV index into an echocardiographic scoring system revealed that the TTE score was highly predictive of RVF (5.0 vs 2.8; P = .0001). In multivariate models combining the TTE score with clinical variables, the score was the most predictive of RVF (odds ratio 1.66, 95% confidence interval 1.06-2.62).

CONCLUSIONS

Preoperative RV FAC, estimated RAP, and LAV index predict postoperative RVF in patients undergoing LVAD implantation. These parameters may be combined into a simple echocardiographic scoring system to provide an additional tool to risk-stratify patients being evaluated for LVAD implantation.

Cavoaortic shunt improves hemodynamics with preserved oxygen delivery in experimental right ventricular failure during left ventricular assist device therapy

OBJECTIVE

Right heart failure is a major cause of morbidity and mortality after left ventricular assist device (LVAD) implantation. This study evaluated the approach of a cavoaortic shunt included in the LVAD circuit, which would aim to relieve venous congestion and improve hemodynamics with preserved oxygen delivery during induced right ventricular failure.

METHODS

Right ventricular failure was induced by coronary ligation in 10 pigs. An LVAD was implanted and a cavoaortic shunt was created from the right atrium and included in the assist circuit. Hemodynamic measures and blood gas analyses were analyzed. Oxygen delivery and oxygen consumption were estimated.

RESULTS

Right atrial pressure decreased from more than 20 mm Hg to 17.2 mm Hg (14.8-18.4) with the LVAD and to 14.1 mm Hg (11.2-15.5) (P < .01) with the LVAD and cavoaortic shunt. Mean arterial pressure increased from 70.9 mm Hg (67.6-79.8) to 81.5 mm Hg (70.8-92.6) (P = .02) with addition of the shunt into the assist circuit. Cardiac output increased from 3.5 L/min (2.6-4.2) to 4.9 L/min (3.5-5.6) (P < .01) with cavoaortic shunting. Oxygen delivery with the cavoaortic shunt was 337 mL/min (± 70) as compared with left ventricular assist alone at 258 mL/min (± 52) (P < .01). Oxygen consumption was restored during use of the cavoaortic shunt.

CONCLUSIONS

A cavoaortic shunt combined with an LVAD during right ventricular failure reduces central venous pressures, increases systemic arterial pressure, and enables increased cardiac output compared with device therapy alone. This was feasible with preserved oxygen delivery.

Are blood stream infections associated with an increased risk of hemorrhagic stroke in patients with a left ventricular assist device?

Blood stream infections (BSIs) are an important cause of morbidity and mortality in patients with left ventricular assist devices (LVADs). The aim of this study was to examine the correlation between hemorrhagic cerebrovascular accident (CVA) and BSI after implantation of LVAD for advanced heart failure (HF). This was a retrospective descriptive review of 87 patients with end-stage HF, who underwent implantation of HeartMate II continuous-flow LVAD over a 4 year period. Blood stream infections were diagnosed by serial blood cultures, and suspected neurological complications including CVAs were confirmed by neuroimaging. Extensive patient chart review was performed, and descriptive characteristics were analyzed using SPSS statistical software. The mean age of our study population was 62.3 ± 12.8 years, and the majority of our patients were males (n = 75, 86.2%). The baseline characteristics were comparable in the patients with and without CVAs. Patients with BSI had a much greater incidence of CVA compared to patients without BSI (n = 13, 43.3% vs. n = 5, 10.0%; p < 0.0001). There was an increased mortality in patients with BSI than those without (n = 57, 65.5% vs. n = 30, 34.5%; p = 0.003). The risk of all CVAs (hemorrhagic/ischemic) was eightfold (odds ratio [OR] = 7.9; 95% confidence interval [CI] = 2.4-25.5; p = 0.001] in patients with BSI. Patients with BSI had a >20-fold risk of hemorrhagic CVA (OR = 24; 95% CI = 2.8-201.1; p = 0.03). Advanced HF patients with LVAD support who developed BSI need urgent evaluation and close monitoring for suspected neurological complications, particularly hemorrhagic CVA.

Newer-generation ventricular assist devices

The latest generation of ventricular assist devices has evolved from the pulsatile, volume-displacement pumps of the 1990s to today's non-pulsatile, constant pressure-generating rotary pumps. These pumps include both centrifugal and axial flow devices that are currently being used or are in advanced development. Rotary pumps have the advantage of a much longer and more reliable duty life than pulsatile pumps. They are also considerably smaller than pulsatile pumps, requiring less invasive surgery for implantation and smaller transcutaneous (electrical rather than pneumatic) drivelines. Most of these devices have been approved as a bridge to transplant (BTT) while some are currently in trials for destination therapy (DT) in Europe (Conformité Européenne (CE) mark) or the United States (Food and Drug Administration (FDA)). This article discusses the current generation of pumps, examining particular design features as highlighted by the designers as well as the current approval status of each device in the United States and Europe.

Cell membrane-inspired phospholipid polymers for developing medical devices with excellent biointerfaces

This review article describes fundamental aspects of cell membrane-inspired phospholipid polymers and their usefulness in the development of medical devices. Since the early 1990s, polymers composed of 2-methacryloyloxyethyl phosphorylcholine (MPC) units have been considered in the preparation of biomaterials. MPC polymers can provide an artificial cell membrane structure at the surface and serve as excellent biointerfaces between artificial and biological systems. They have also been applied in the surface modification of some medical devices including long-term implantable artificial organs. An MPC polymer biointerface can suppress unfavorable biological reactions such as protein adsorption and cell adhesion - in other words, specific biomolecules immobilized on an MPC polymer surface retain their original functions. MPC polymers are also being increasingly used for creating biointerfaces with artificial cell membrane structures.

Severity of oxidative stress and inflammatory activation in end-stage heart failure patients are unaltered after 1 month of left ventricular mechanical assistance

This study investigates the impact of early left ventricular (LV)-mechanical unloading on systemic oxidative stress and inflammation in terminal heart failure patients and their impact both on multi organ failure and on intensive care unit (ICU) stay. Circulating levels of urinary 15-isoprostane-F(2t) (8-epi-PGF2(α)) and pro-inflammatory markers [plasma interleukin (IL)-6, IL-8, and urinary neopterin, a monocyte activation index] were analyzed in 20 healthy subjects, 22 stable end-stage heart failure (ESHF) patients and in 23 LV assist device (LVAD) recipients at pre-implant and during first post-LVAD (PL) month. Multi-organ function was evaluated by total Sequential Organ Failure Assessment (tSOFA) score. In LVAD recipients the levels of oxidative-inflammatory markers and tSOFA score were higher compared to other groups. After device implantation 8-epi-PGF2(α) levels were unchanged, while IL-6, and IL-8 levels increased during first week, and at 1month returned to pre-implant values, while neopterin levels increased progressively during LVAD support. The tSOFA score worsened at 1 PL-week with respect to pre-implant value, but improved at 1 PL-month. The tSOFA score related with IL-6 and IL-8 levels, while length of ICU stay related with pre-implant IL-6 levels. These data suggest that hemodynamic instability in terminal HF is associated to worsening of systemic inflammatory and oxidative milieu that do not improve in the early phase of hemodynamic recovery and LV-unloading by LVAD, affecting multi-organ function and length of ICU stay. This data stimulate to evaluate the impact of inflammatory signals on long-term outcome of mechanical circulatory support.

Temporary percutaneous right ventricular support using a centrifugal pump in patients with postoperative acute refractory right ventricular failure after left ventricular assist device implantation

OBJECTIVE

Acute right ventricular (RV) failure is a life-threatening condition with a poor prognosis, and sometimes the use of mechanical circulatory support is inevitable. In this article, we describe our experience using a centrifugal pump as a temporary percutaneous right ventricular assist device (RVAD) in patients with postoperative acute refractory RV failure after left ventricular assist device (LVAD) implantation.

METHODS

We retrospectively reviewed eight consecutive patients with acute RV failure who underwent temporary percutaneous RVAD implantation using a centrifugal pump after LVAD implantation between April 2008 and February 2011. A Dacron graft was attached to the main pulmonary artery and passed through a subxiphoid exit, where the outflow cannula was inserted. The inflow cannula was percutaneously cannulated using Seldinger's technique in the femoral vein. The chest was definitely closed. The technique allowed bedside removal, avoiding chest re-opening.

RESULTS

The median patient age was 52 years (range: 41-58). The median duration of support was 14 days (range: 12-14). RV systolic function improved; central venous pressure and mean pulmonary artery pressure decreased significantly after RVAD support. In three patients, an oxygenator was integrated into the RVAD due to impaired pulmonary function. Six patients were successfully weaned. Five patients survived to hospital discharge. Technical problems or serious complications concerning decannulation were not observed.

CONCLUSION

This report suggests that implantation of temporary percutaneous RVAD using a centrifugal pump is a safe alternative in the treatment of postoperative acute refractory RV failure. Ease of device implantation, weaning, explantation, and limited number of complications justify a liberal use.

Transplant infectious disease: implications for critical care nurses

Infection is an important issue for critical care nurses as they care for patients throughout all phases of the transplant continuum: potential organ donors, transplant candidates, and transplant recipients. This article has reviewed salient issues relative to infections in each of these patient populations, including patients with VADs, and has highlighted key points pertaining to bacterial, viral, and fungal infections.

Association of pre-operative interleukin-6 levels with Interagency Registry for Mechanically Assisted Circulatory Support profiles and intensive care unit stay in left ventricular assist device patients

BACKGROUND

Inflammatory mechanisms are associated with worse prognosis in end-stage heart failure (ESHF) patients who require left ventricular assist device (LVAD) support. Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profiles describe patient condition at pre-implant and outcome. This study assessed the relationship among inflammation patterns and INTERMACS profiles in LVAD recipients.

METHOD

Thirty ESHF patients undergoing LVAD implantation as bridge to transplant were enrolled. Blood and urine samples were collected pre-operatively and serially up to 2 weeks post-operatively for assessment of inflammatory markers (plasma levels of interleukin [IL]-6, IL-8, IL-10, and osteopontin, a cardiac inflammatory-remodeling marker; and the urine neopterin/creatinine ratio, a monocyte activation marker). Multiorgan function was evaluated by the total sequential organ failure assessment (tSOFA) score. Outcomes of interest were early survival, post-LVAD tSOFA score, and intensive care unit (ICU) length of stay.

RESULTS

Fifteen patients had INTERMACS profiles 1 or 2 (Group A), and 15 had profiles 3 or 4 (Group B). At pre-implant, only IL-6 levels and the IL-6/IL-10 ratio were higher in Group A vs B. After LVAD implantation, neopterin/creatinine ratio and IL-8 levels increased more in Group A vs B. Osteopontin levels increased significantly only in Group B. The tSOFA score at 2 weeks post-LVAD and ICU duration were related with pre-implant IL-6 levels.

CONCLUSIONS

The INTERMACS profiles reflect the severity of the pre-operative inflammatory activation and the post-implant inflammatory response, affecting post-operative tSOFA score and ICU stay. Therefore, inflammation may contribute to poor outcome in patients with severe INTERMACS profile.

Timely use of a CentriMag heart assist device improves survival in postcardiotomy cardiogenic shock

BACKGROUND

Postcardiotomy cardiogenic shock (PCS) is often fatal despite inotropic and circulatory support. We compared our experience with the CentriMag left ventricular assist device (LVAD) for patients with PCS at two time periods: in the operating room (OR) after unsuccessful weaning from cardiopulmonary bypass (CPB) and after transfer to the intensive care unit (ICU).

METHODS

We reviewed 22 patients' records (13 men, nine women; age, 65 ± 12 years) who underwent open heart surgery (January 2004 to September 2009) and required LVAD support for PCS despite maximal inotropic and intra-aortic balloon pump (IABP) support. In ten patients who could not be weaned from CPB despite high-dose inotropic therapy (≥ 3 agents) and IABP support, the CentriMag was implanted in the OR (immediate group). The other 12 patients were weaned from CPB with high-dose inotropic therapy and IABP but became increasingly unstable or had a cardiac arrest in the ICU, and the CentriMag was implanted for circulatory support (delayed group).

RESULTS

Preoperatively, the average ejection fraction was 40% ± 12%, the creatinine level was 1.6 ± 0.6 mg/dL, and the European Systematic Coronary Risk Evaluation was 13.1 ± 4.6. The duration of CentriMag support was 5 ± 3 days. The immediate group had significantly better survival (7/10 vs. 2/12, p = 0.027), higher cardiac index (2.4 ± 0.3 L/min/m(2) vs. 1.7 ± 0.3 L/min/m(2), p = 0.001), and lower pulmonary capillary wedge pressure (20 ± 6 mmHg vs. 29 ± 8 mmHg, p = 0.024) than the ICU group. No perioperative complications related to device implantation occurred.

CONCLUSION

In patients with PCS, timely placement of a CentriMag LVAD may increase the chance of eventual recovery. 

Ventricular assist device implantation in patients on percutaneous extracorporeal life support without switching to conventional cardiopulmonary bypass system

OBJECTIVES

Ventricular assist device (VAD) implantation using cardiopulmonary bypass (CPB) is an established procedure. However, the well-described complications of CPB may exacerbate multiple organ failure and increase blood product transfusions especially in end-stage heart failure patients.

METHODS

We describe our successful experience in six consecutive patients with profound cardiogenic shock, who were provided on an emergency basis with a percutaneous extracorporeal life support (ECLS) system via the peripheral vessels. After stabilization, a VAD was implanted using ECLS without switching to a conventional CPB system to reduce its side effects. We compared the data with those of 11 patients in whom the VAD was placed with the aid of an additional CPB system.

RESULTS

The six patients demonstrated a shorter duration of operating room time compared with the patients requiring CPB for device placement. During and after surgery, blood loss and blood product transfusions were lower in these patients. The need for mechanical ventilation and inotropic support was shorter and the survival rate (100% at 30 days, 83.3% at 3 months and 83.3% at 6 months) was higher when compared with patients who were operated upon with CPB. Two patients were successfully bridged to transplantation. One patient died due to cerebral bleeding after 7 weeks.

CONCLUSIONS

Our experience suggests that VAD implantation using percutaneous ECLS without switching to conventional CPB is a safe alternative in the bridge to bridge concept, especially in high-risk patients with cardiogenic shock who would benefit from the avoidance of the adverse sequels associated with conventional CPB.

Numerical Simulation of LVAD Inflow Cannulas with Different Tip

The tip structure of LVAD inflow cannula is one of major factors to lead adverse events such as thrombosis and suction leading to obstruction. In this research, four kinds of tips that had been used in inflow cannulas were selected and designed. The flow field of the four inflow cannulas inserted into the apex of left ventricle (LV) was numerically computed by computational fluid dynamics. The flow behavior was analyzed in order to compare the blood compatibility and suction in left ventricle and cannulas after the inflow cannulas with different tips were inserted to the apex of LV. The results showed that the cannula tip structure affected the LVAD performance. Among these four cannulas, the trumpet-tipped inflow cannula owned the best performance in smooth flow velocity distribution without backflow or low-velocity flow so that it was the best in blood compatibility. Nevertheless, the caged tipped cannula was the worst in blood compatibility. And the blunt-tipped and beveled tipped inflow cannulas may obstruct more easily than trumpet and caged tipped inflow cannulas because of their shape. The study indicated that the trumpet tip was the most preferable for the inflow cannula of long-term LVAD.

Durable mechanical circulatory support devices

Individuals afflicted with advanced systolic heart failure who have become unresponsive to standard medical and electrical therapies are categorized as having American Heart Association stage D heart failure. The high mortality rates for medically treated stage D heart failure have not improved in the last 10 years, and patients at this advanced stage require either palliative measures or surgical management of heart failure. In recent years, surgically implanted ventricular assist devices (VADs) have become available for long-term use and are now commonly used as a therapy for advanced heart failure. The data generated from this early experience have clearly shown that VADs improve survival and quality of life in patients with advanced heart failure when implanted as a temporary measure or as long-term support. However, with a growing heart failure population, there is much work to be done to continually improve VAD technology, patient selection criteria, and postimplantation management to define the optimal role for assist devices in the management of systolic heart failure.

Who needs an RVAD in addition to an LVAD?

Mechanical circulatory support using left ventricular assist devices (LVAD) has become an accepted mode of therapy for both bridging patients with end-stage heart failure to transplant and as a destination therapy. Right ventricular (RV) dysfunction is common after LVAD insertion and is a significant source of morbidity and mortality in patients undergoing LVAD placement. Several studies have identified clinical, laboratory, hemodynamic, and echocardiographic parameters that may serve as risk factors for RV dysfunction after LVAD placement. Furthermore, scoring systems have been established to help quantitatively predict the potential need for RV support after LVAD placement.

Platelet activation in ovines undergoing sham surgery or implant of the second generation PediaFlow pediatric ventricular assist device

The PediaFlow pediatric ventricular assist device (VAD) is a magnetically levitated turbodynamic pump under development for circulatory support of small children with a targeted flow rate range of 0.3-1.5 L/min. As the design of this device is refined, ensuring high levels of blood biocompatibility is essential. In this study, we characterized platelet activation during the implantation and operation of a second generation prototype of the PediaFlow VAD (PF2) and also performed a series of surgical sham studies to examine purely surgical effects on platelet activation. In addition, a newly available monoclonal antibody was characterized and shown to be capable of quantifying ovine platelet activation. The PF2 was implanted in three chronic ovine experiments of 17, 30, and 70 days, while surgical sham procedures were performed in five ovines with 30-day monitoring. Blood biocompatibility in terms of circulating activated platelets was measured by flow cytometric assays with and without exogenous agonist stimulation. Platelet activation following sham surgery returned to baseline in approximately 2 weeks. Platelets in PF2-implanted ovines returned to baseline activation levels in all three animals and showed an ability to respond to agonist stimulation. Late-term platelet activation was observed in one animal corresponding with unexpected pump stoppages related to a manufacturing defect in the percutaneous cable. The results demonstrated encouraging platelet biocompatibility for the PF2 in that basal platelet activation was achieved early in the pump implant period. Furthermore, this first characterization of the effect of a major cardiothoracic procedure on temporal ovine platelet activation provides comparative data for future cardiovascular device evaluation in the ovine model.

Intracranial hemorrhage surgery on patients on mechanical circulatory support: a case series

BACKGROUND

Cardiac disease is the leading cause of death in the United States and late-stage heart failure is associated with a high level of morbidity and mortality. The ventricular assist devices and extracorporeal membrane oxygenators are the mainstay of mechanical circulatory support devices for the patients with extremely low cardiac output. However, they come at a price of significant risk factors, including intracranial hemorrhage. The incidence of intracranial hemorrhage on extracorporeal membrane oxygenators and on ventricular assist devices is 37% and 13% to 14%, respectively.

METHODS/RESULTS

The cases in this series focus on the risks of ICH and the decompressive craniotomies that were carried out on patients while they were on mechanical circulatory support. The intraoperative anesthetic management for patients on mechanical circulatory support for the noncardiothoracic anesthesiologist is highlighted.

CONCLUSIONS

The results of recent cardiothoracic surgery trials have led to an increase of surgical management instead of medical management in the treatment of heart failure. Although most agree with the immediate reversal of anticoagulation and antiplatelet therapy, there is no standard protocol for restarting anticoagulation or antiplatelet therapy after craniotomy in this population. The standard practices of resuscitation and ACLS including inotropes, vasopressors, and vasodilators (with the exception of chest compressions that can dislodge the devices), can be used as needed. The identification of cardiothoracic surgeons and perfusionists who are available for immediate assistance as and when required during the surgery and transportation is an important factor.

Inhaled nitric oxide after left ventricular assist device implantation: a prospective, randomized, double-blind, multicenter, placebo-controlled trial

BACKGROUND

Used frequently for right ventricular dysfunction (RVD), the clinical benefit of inhaled nitric oxide (iNO) is still unclear. We conducted a randomized, double-blind, controlled trial to determine the effect of iNO on post-operative outcomes in the setting of left ventricular assist device (LVAD) placement.

METHODS

Included were 150 patients undergoing LVAD placement with pulmonary vascular resistance ≥ 200 dyne/sec/cm(-5). Patients received iNO (40 ppm) or placebo (an equivalent concentration of nitrogen) until 48 hours after separation from cardiopulmonary bypass, extubation, or upon meeting study-defined RVD. For ethical reasons, crossover to open-label iNO was allowed during the 48-hour treatment period if RVD criteria were met.

RESULTS

RVD criteria were met by 7 of 73 patients (9.6%; 95% confidence interval, 2.8-16.3) in the iNO group compared with 12 of 77 (15.6%; 95% confidence interval, 7.5-23.7) who received placebo (p = 0.330). Time on mechanical ventilation decreased in the iNO group (median days, 2.0 vs 3.0; p = 0.077), and fewer patients in the iNO group required an RVAD (5.6% vs 10%; p = 0.468); however, these trends did not meet statistical boundaries of significance. Hospital stay, intensive care unit stay, and 28-day mortality rates were similar between groups, as were adverse events. Thirty-five patients crossed over to open-label iNO (iNO, n = 15; placebo, n = 20). Eighteen patients (iNO, n = 9; placebo, n = 9) crossed over before RVD criteria were met.

CONCLUSIONS

Use of iNO at 40 ppm in the perioperative phase of LVAD implantation did not achieve significance for the primary end point of reduction in RVD. Similarly, secondary end points of time on mechanical ventilation, hospital or intensive care unit stay, and the need for RVAD support after LVAD placement were not significantly improved.

Computational characterization of flow and hemolytic performance of the UltraMag blood pump for circulatory support

The Levitronix UltraMag blood pump is a next generation, magnetically suspended centrifugal pump and is designed to provide circulatory support for pediatric and adult patients. The aim of this study is to investigate the hemodynamic and hemolytic characteristics of this pump using the computational fluid dynamics (CFD) approach. The computational domain for CFD analysis was constructed from the three-dimensional geometry (3D) of the UltraMag blood pump and meshed into 3D tetrahedral/hybrid elements. The governing equations of fluid flow were computationally solved to obtain a blood flow through the blood pump. Further, hemolytic blood damage was calculated by solving a scalar transport equation where the scalar variable and the source term were obtained utilizing an empirical power-law correlation between the fluid dynamic variables and hemolysis. To obtain mesh independent flow solution, a comparative examination of vector fields, hydrodynamic performance, and hemolysis predictions were carried out. Different sizes of tetrahedral and tetrahedral/hexahedral mixed hybrid models were considered. The mesh independent solutions were obtained by a hybrid model. Laminar and SST κ-ω turbulence flow models were used for different operating conditions. In order to pinpoint the most significant hemolytic region, the flow field analysis was coupled to the hemolysis predictions. In summary, computational characterization of the device was satisfactorily carried out within the targeted operating conditions of the device, and it was observed that the UltraMag blood pump can be safely operated for its intended use to create a circulatory support for both pediatric and adult-sized patients.

Early expression of pro- and anti-inflammatory cytokines in left ventricular assist device recipients with multiple organ failure syndrome

To assess whether the combined evaluation of total Sequential Organ Failure Assessment (t-SOFA) score and pro- and anti-inflammatory cytokine profiles early after left ventricular assist device (LVAD) implant discriminates patients at high risk for multiple organ failure syndrome (MOFS) in the first month post-LVAD, we analyzed plasma interleukin (IL)-6, IL-8, IL-10, IL-1ra, IL-1beta, tumor necrosis factor-alpha (TNF-alpha), and urine neopterin levels before (day 0) and at 4 hours, 1, 3, 7, 14, and 30 days after LVAD implant in 23 recipients. Eight patients died of MOFS between days 7 and 30 (nonsurvivors). At preimplant, only blood urea nitrogen and age were higher in nonsurvivors than survivors. At 4 hours, IL-8, IL-10, and IL1-ra levels were higher in nonsurvivors than in survivors; t-SOFA was also higher and peaked on day 3 in nonsurvivors. Only IL-8 levels on day 1 were significantly associated with a t-SOFA > or =10 on day 3 (odds ratio 1.10, 95% confidence interval 1.01-1.21, p = 0.04). Neopterin, marker of monocyte activation, increased significantly only in nonsurvivors (p < 0.001). These findings suggest that an activated inflammatory system soon after LVAD implant is implicated in MOFS development. Early monitoring of inflammatory mediators and t-SOFA score may be a valuable tool for outcome prediction in LVAD recipients.

Aortic valve pathophysiology during left ventricular assist device support

The increased applicability and excellent results with left ventricular assist devices (LVADs) have revolutionized the available treatment options for patients with advanced heart failure. Pre-existing valve abnormalities are common in this population, and subsequent development of valve abnormalities after LVAD placement is also often noted. Although native mitral and tricuspid valve disease is more common in heart failure patients before LVAD placement, aortic valves are much more likely to generate abnormal pathophysiology in the LVAD patient during as well as after LVAD placement. The aim of this comprehensive review is to review aortic valve function in LVAD patients and highlight the consideration of pre-existing valve disease on patient treatment at the time of LVAD implant. The basis for structural changes leading to valve pathophysiology during and after LVAD placement will be described, providing a basis for improved clinical understanding and new strategies to prevent these conditions.

Managing drugs and devices in patients with permanent ventricular assist devices

Patients will be considered for destination mechanical circulatory support device (MCSD) implantation when all other organ-saving treatment options have failed and they are not eligible for heart transplantation. Current medical evidence suggests that only for those patients who are inotrope-dependent and therefore likely have a 1-year survival probability without MCSD implantation of less than 50%, MCSD intervention will add to survival and quality-of-life benefit. Suitable candidates for MCSD are those patients who have a high risk of dying from heart failure but acceptable noncardiac risk. Evaluation of patients for MCSD requires a systematic and critical review of all organ systems and of the psychosocial situation. Specifically, right ventricular function and risk of right ventricular failure should be evaluated before planning destination MCSD implantation. Treatment will focus on prompt recovery from MCSD implantation, maintaining optimal treatment for heart failure, and preventing/treating MCSD complications, including infection, bleeding, coagulopathy, right heart failure, and device dysfunction. MCSD programs should be organized as an advanced heart failure center directed by specialized heart failure cardiologists, surgeons expert at implant and management of MCSD, specialized nurses, social workers, psychologists, financial experts, and physical therapists. MCSD practice is based on a patient-centered theory, with an appropriate understanding of the respective roles of the physician and the patient during their iterative encounters in which the patient is an autonomous person making responsible personal health decisions while the health care team is providing continued expert and empathic counseling about various options, based on systematic outcomes research (eg, by participation in the Interagency Registry for Mechanically Assisted Circulatory Support - MCSD database ).

New prioritization of heart transplant candidates on mechanical circulatory support in an era of severe donor shortage

BACKGROUND

Nearly all patients receiving heart transplantation (HTx) in Germany are now those listed in urgent status. In this study we review urgency-based allocation policy for HTx candidates with ventricular assist devices (VADs).

METHODS

We retrospectively studied 345 adult candidates for de novo HTx. Group U (n = 160) comprised patients primarily listed in urgent status without VAD. Group VAD-45 (n = 167) comprised patients with intended bridging to HTx who survived >45 days after VAD implantation (after initial drop in survival rates). Among these patients, those who died of stroke or were awarded urgent status due to difficulties of coagulation management (thrombus formation, thromboembolism and bleeding) in the first year after VAD implantation were assigned to Group COAG (n = 36), and those who died or were awarded urgent status due to device-related infection in the same period were assigned to Group INF (n = 31). Actuarial survival rates were studied in each group.

RESULTS

Survival rates during support in Group VAD-45 were comparable to those during urgent status in Group U. Bridge-to-transplant rate was 63.9% in Group COAG and 58.1% in Group INF. The post-transplant 3-year survival rate of 85.3% in Group COAG was significantly higher than that in Group INF (46.8%, p < 0.01) and Group U (62.4%, p < 0.05).

CONCLUSIONS

Patients who have a VAD for >45 days should be awarded some priority for urgent HTx, which is currently prohibited in Germany. Patients listed in urgent status due to difficulties of coagulation management should be prioritized over those listed for device-related infection to make effective use of limited resources.