Improved survival and decreasing incidence of adverse events with the HeartMate II left ventricular assist device as bridge-to-transplant therapy. Ann Thorac Surg. 2008;86:1227-1234. [PMID: 18805167 DOI: 10.1016/j.athoracsur.2008.06.030]

Giant ventral hernia following left ventricular assist device bridge to heart transplantation

Ventral hernias following left ventricular assist device (LVAD) placement are rare. With the improvement in technology, and miniaturization of devices associated with intrapericardial placement, these complications have largely been abolished. The mere presence of a large ventral hernia should not exclude recipients from being candidates for orthotopic heart transplantation.

Antithrombotic therapy for durable left ventricular assist devices - current strategies and future directions

Left ventricular assist devices (LVADs) improve survival and quality of life for patients with advanced heart failure but are associated with high rates of thromboembolic and hemorrhagic complications. Antithrombotic therapy is required following LVAD implantation, though practices vary. Identifying a therapeutic strategy that minimizes the risks of thromboembolic and hemorrhagic complications is critical to optimizing patient outcomes and is an area of active investigation. This paper reviews strategies for initiating and maintaining antithrombotic therapy in durable LVAD recipients, focusing on those with centrifugal-flow devices.

Long-term preservation of functional capacity and quality of life in advanced heart failure patients with bridge to transplant therapy: A report from Japanese nationwide multicenter registry

BACKGROUND

Under the revised heart allocation system in the United States, bridge to transplant (BTT) patients with left ventricular assist device (LVAD) have a longer waitlist period, as they are now lowly prioritized. However, little is known regarding the long-term trajectory of functional capacity (FC) and health-related quality of life (HR-QOL) among BTT-LVAD patients.

METHODS

We retrospectively analyzed 442 consecutive patients with BTT-LVAD between April 2013 and May 2019 from a Japanese nationwide registry. FC (New York Heart Association [NYHA] functional class, peak oxygen uptake [VO₂], and 6-min walk test [6MWT]) and HR-QOL (European Quality of Life [EQ-5D index] and Visual Analogue Scale [EQ-VAS]) were assessed at baseline and for up to 60 months after LVAD implantation.

RESULTS

During the follow-up period of 30 months (IQR 18-42 months), 100 (22.6%) patients underwent transplantation, 37 (8.3%) died, and 14 (3.1%) underwent explantation for recovery. Mean peak VO₂, 6MWT distance, EQ-5D index, and EQ-VAS significantly improved 3 months after LVAD implantation (p = 0.0012, p = 0.0037, p < 0.001, p < 0.001, respectively). Furthermore, these improvements were sustained for up to 60 months following LVAD implantation. Major adverse events including device failure, infection, stroke, and bleeding, which occurred within the first 3 months after LVAD implantation may have not affected FC or HR-QOL for up to 60 months (p = 0.15, p = 0.22, respectively).

CONCLUSIONS

BTT patients showed long-term preservation of FC and HR-QOL, suggesting that BTT remains an option despite the long waiting time to HTx.

Smoking and the Risk of Stroke in Patients with a Left Ventricular Assist device

There are limited data on the association of smoking with the risk of stroke following left ventricular assist device (LVAD) implantation. We designed this study to analyze the impact of smoking status at the time of LVAD implantation on stroke. We hypothesized that current smokers are at increased risk of stroke when compared with patients who were former or never smokers. The study population comprised of 369 patients in the University of Rochester Medical Center LVAD database, implanted with an LVAD between 2008 and 2018. Patients were stratified as current smoker (smoking within 30 days before LVAD implantation), former smoker, and never smoker. Stroke was defined as a transient ischemic attack or cerebrovascular accident (hemorrhagic or ischemic). There were 45 current smokers, 198 former smokers, and 125 never smokers. Current smokers were younger (mean age 50 ± 11 years), as compared with former (58 ± 12 years) and never smokers (56 ± 13 years) p < 0.001. At 2 years following LVAD implantation, the cumulative incidence of stroke was significantly higher among current smokers (39%) as compared with former and never smokers (16% and 15%, respectively; p = 0.022 for the overall difference during follow-up). In a multivariate model adjusted for significant clinical variables, current smoking was associated with a significant 88% (p = 0.018) higher risk of stroke when compared with all noncurrent smokers. In conclusion, our data suggest that LVAD candidates who are current smokers experience a significantly higher risk of stroke following device implantation.

Mock circulatory loops used for testing cardiac assist devices: A review of computational and experimental models

Heart failure is a major health risk, and with limited availability of donor organs, there is an increasing need for developing cardiac assist devices (CADs). Mock circulatory loops (MCL) are an important in-vitro test platform for CAD's performance assessment and optimisation. The MCL is a lumped parameter model constructed out of hydraulic and mechanical components aiming to simulate the native cardiovascular system (CVS) as closely as possible. Further development merged MCLs and numerical circulatory models to improve flexibility and accuracy of the system; commonly known as hybrid MCLs. A total of 128 MCLs were identified in a literature research until 25 September 2020. It was found that the complexity of the MCLs rose over the years, recent MCLs are not only capable of mimicking the healthy and pathological conditions, but also implemented cerebral, renal and coronary circulations and autoregulatory responses. Moreover, the development of anatomical models made flow visualisation studies possible. Mechanical MCLs showed excellent controllability and repeatability, however, often the CVS was overly simplified or lacked autoregulatory responses. In numerical MCLs the CVS is represented with a higher order of lumped parameters compared to mechanical test rigs, however, complex physiological aspects are often simplified. In hybrid MCLs complex physiological aspects are implemented in the hydraulic part of the system, whilst the numerical model represents parts of the CVS that are too difficult to represent by mechanical components per se. This review aims to describe the advances, limitations and future directions of the three types of MCLs.

Characteristics of strokes associated with centrifugal flow left ventricular assist devices

Stroke is a devastating complication of left ventricular assist device (LVAD) therapy. Understanding the characteristics, risk factors and outcomes of strokes associated with the centrifugal flow LVADs is important to devise better strategies for management and prevention. This is a retrospective cohort study at a single US academic medical center. The cohort includes patients who received a first time Heartmate 3 (HM3) or Heartware (HVAD) LVAD between September 2009 through February 2018 and had a stroke while the LVAD was in place. Descriptive statistics were used when appropriate. A logistic regression analysis was used to determine predictors of poor outcome. Out of a total of 247 patients, 12.1% (N = 30, 24 HVAD and 6 HM3) had a stroke (63% ischemic) and 3 of these patients had pump thrombosis. Events per patient year (EPPY) were similar for HVAD and HM3 patients (0.3 ± 0.1). INR was subtherapeutic in 47.4% of ischemic stroke patients and supratherapeutic in 18.2% of hemorrhagic stroke patients. Concurrent infections were more common in the setting of hemorrhagic stroke than ischemic stroke (45.4% vs 5.3%, p = 0.008). Strokes were severe in most cases, with initial NIH stroke scale (NIHSS) higher in HM3 patients compared to HVAD patients (mean 24.6 vs 16) and associated with high in-patient mortality (21.1% of ischemic stroke vs. 88.8% of hemorrhagic stroke). Predictors of death within 30 days and disability at 90 days included creatinine at stroke onset, concurrent infection, hemorrhaghic stroke, and initial stroke severity (NIHSS). A score derived from these variables predicted with 100% certainty mortality at 30 days and mRS ≥ 4 at 90 days. For patients with centrifugal flow LVADs, ischemic strokes were more common but hemorrhagic strokes were associated with higher in-patient mortality and more frequently seen in the setting of concurrent infections. Infections, sub or supratherapeutic INR range, and comorbid cardiovascular risk factors may all be contributing to the stroke burden. These findings may inform future strategies for stroke prevention in this population.

Ventricular Assist Devices and Chronic Kidney Replacement Therapy: Technology and Outcomes

Heart failure and kidney failure are very common conditions, precipitating and exacerbating each other. Left ventricular assist devices (LVADs) represent a relatively new technology for treatment of advanced heart failure. Kidney dysfunction, if present, makes candidate selection for LVADs challenging and contributes to multiple complications while the patients are on an LVAD support. Although kidney function generally improves after LVAD implantation, some patients develop acute and then chronic kidney disease sometimes requiring kidney replacement therapies (KRTs). Overall, chronic KRT in LVAD recipients is feasible and well tolerated, but routine technique of blood pressure monitoring should be adjusted to the continuous blood flow. Both hemodialysis and peritoneal dialysis can be used. Unique challenges for chronic KRT posed by the presence of LVAD are discussed in this review.

Use of durable left ventricular assist devices for high-risk patients: Korean experience before insurance coverage

Background

Left ventricular assist devices (LVADs) were not covered by the Korean national insurance until September 2018, and they were implanted at the patient’s own or a third party’s expense. However, there have been no reports on using an LVAD without insurance coverage or manufacturer support.

Methods

We reviewed 23 patients who underwent durable LVAD implantation at our institution from August 2012 to September 2018. Patients with temporary LVADs using extracorporeal or paracorporeal circulation were excluded. The available devices were the HeartMate II^TM (HMII) and HeartWare^TM Ventricular Assist Device (HVAD). The primary outcome was 30-day mortality. The secondary outcomes were postoperative complications and late mortality.

Results

The mean age of the patients was 68.7±9.9 years. The study sample comprised six female (26.1%) and 17 male (73.9%) patients. All patients had modifiable (bridge to candidacy) or unmodifiable absolute (destination therapy) contraindications for heart transplantation (HT). Among the patients in this study, 12 (52.2%) had ischemic cardiomyopathy and 11 (47.8%) had non-ischemic cardiomyopathy. Nine patients (39.1%) had temporary mechanical circulatory support such as extracorporeal membrane oxygenation or a temporary LVAD in place preoperatively. The average duration of LVAD support was 618.6±563.2 days (range, 59–2,285 days). There was no 30-day mortality. Four patients (17.4%) underwent HT. Six patients (26.1%) underwent re-exploration for postoperative bleeding, and one patient (4.3%) had a disabling stroke after discharge. The estimated survival rates at 12 and 24 months were 89.2% and 68.8%, respectively.

Conclusions

All patients who received LVADs before insurance coverage had contraindications for HT. The overall outcomes were comparable with those reported in the international registry.

Emergent General Surgery Operations in Patients With Left Ventricular Assist Devices

BACKGROUND

The left ventricle assist device (LVAD) patient population is rapidly expanding. Unique characteristics of these patients complicate the management of noncardiac surgical problems. Emergent general surgery (EGS) intervention is often warranted but remains poorly described. We reviewed EGS consultations in LVAD patients to better understand these patients.

METHODS

During a 12-year period, 301 LVAD patients were reviewed. Demographics, comorbidities, reason for EGS consultation, operative intervention, transplantation, and mortality were analyzed. Wilcoxon, Fisher's exact, and chi-square tests were used for analysis. Statistical significance was P < .05.

RESULTS

A total of 139 (46.2%) patients required EGS consultation. EGS consultations were older (63 vs 57 years; P = .002), primarily Caucasian (86%), and male (83%) with average preimplant cardiac index of 1.84. Comorbidities were similar between those with and without EGS consultation. Gastrointestinal (GI) bleeding was the most common reason for consultation (53%), followed by abdominal pain (22%) and bowel ischemia/obstruction (19%). Of EGS consultations, 77% were on warfarin and 60% on aspirin. Procedures were not withheld: 46% required esophagogastroduodenoscopy (EGD) and 30% required colonoscopy. Surgical intervention was performed in 28% of EGS consults-49% emergent (within 24 hours) and 44% urgent (during hospitalization). Mean time to surgery was 48 days after LVAD placement. EGS intervention precluded 7 (18%) patients from heart transplantation and 10 (26%) patients suffered perioperative mortality. Elevated lactic acid was associated with increased mortality.

CONCLUSION

EGS consultation is necessary in almost half of all LVAD patients, most commonly for GI bleed. EGD/colonoscopy can be safely used to manage the majority of these consultations; one-third will require surgery. High lactic acid is associated with higher mortality. Additional analysis of this population is required for improving surgical management.

Outcomes in patients who underwent a concomitant tricuspid valve procedure during left ventricular assist device implantation

BACKGROUND

Study findings have been inconsistent regarding whether a concomitant tricuspid valve replacement or repair performed concurrently with continuous-flow left ventricular assist device (CF-LVAD) implantation has additive clinical benefit in patients with severe tricuspid valve regurgitation (TR).

AIM OF STUDY

To determine the effect of performing a concomitant tricuspid valve procedure (TVP) at the time of CF-LVAD implantation on patient outcomes.

METHODS

We retrospectively reviewed our single-institution experience in 526 patients who underwent primary implantation of a CF-LVAD between November 2003 and March 2016. We identified 59 (11.2%) patients who had severe TR at the time of implantation and analyzed the effect of performing a concomitant TVP at the time of CF-LVAD implantation on the rate of survival, incidence of postoperative right heart failure (RHF), recurrence of TR, and incidence of 30-day readmission.

RESULTS

We did not observe a significant difference in the overall survival rate (P = .51), incidence of postoperative RHF (P = .26), or recurrence of TR (P = .73) between patients with severe TR who underwent a TVP and those who did not at the time of CF-LVAD implantation. However, the incidence of 30-day readmission was significantly lower in patients who underwent a TVP than in those who did not (P = .002).

CONCLUSIONS

Performing a concomitant TVP at the time of CF-LVAD implantation did not improve patient outcomes but reduced the incidence of 30-day readmission.

Effects of Systemic and Device-Related Complications in Patients Bridged to Transplantation With Left Ventricular Assist Devices

BACKGROUND

The use of left ventricular assist devices (LVADs) as a bridge to heart transplantation has increased rapidly over the last 2 decades. We aim to explore the effect of pretransplant systemic and device-related complications on posttransplant survival for patients bridged with LVADs.

MATERIALS AND METHODS

The United Network of Organ Sharing (Organ Procurement and Transplantation Network) database was queried for all adult heart transplant recipients (aged ≥ 18 y) transplanted from April 1, 2015, to June 31, 2018. Device-related complications included thrombosis, device infection, device malfunction, life-threatening arrhythmia, and other device complications. Systemic complications included a new dialysis need or ventilator dependence between the time of listing and transplantation, transfusion, or systemic infection requiring treatment with intravenous antibiotics within 2 wk of transplantation.

RESULTS

A total of 2131 patients were identified as requiring LVAD support before transplantation. LVAD patients had high rates of preoperative systemic complications (53%) and high rates of device-related complications (42.7% experienced at least one device-related complication). Kaplan-Meier analysis revealed a significantly decreased 1-y survival for LVAD patients bridged to transplantation who experienced a pretransplant systemic complication (P = 0.041). Interestingly, preoperative device-related complications had no effect on 1-y posttransplantation survival (P = 0.93). Multivariate Cox modeling revealed that systemic complications were associated with a significantly increased risk of posttransplant mortality for LVAD patients (hazard ratio 1.45; P = 0.033).

CONCLUSIONS

Recipients who suffered a systemic complication while awaiting heart transplantation experienced higher short-term mortality rates. Device-related complications do not appear to impact posttransplantation outcomes.

Caring for Patients With Ventricular Assist Devices: A Mini-Review of the Literature

Heart transplantation, one of the treatment options for end-stage heart failure, is still regarded as the gold standard treatment to improve quality and length of life. However, the rapid increase in the number of patients waiting for heart transplantation and the inadequate number of donors makes heart transplantation a less feasible option and increases the need for ventricular assist devices as an alternative. The success of ventricular assist device implantation requires the collaboration of a multidisciplinary team consisting of cardiac surgeons, nurses, ventricular assist device coordinators, cardiologist, cardiac anesthesia specialists, perfusionists, and physiotherapists. Nurses working in different fields such as intensive care units, operating rooms, outpatient clinics, and ventricular assist device coordination units have important responsibilities in multidisciplinary teams. In this study, national and international studies on the responsibilities of nurses for the management and care of ventricular assist devices were reviewed. Nurses undertake many tasks, especially in the postoperative care of patients and in preparing them for discharge. Important responsibilities of nurses in the care of patients with ventricular assist devices include monitoring complications, managing equipment and emergency situations, establishing dressing change protocols, organizing daily life activities, determining rehabilitation needs, ensuring use of medicines, and providing comprehensive discharge education. Organizational and communication skills of nurses working with multidisciplinary teams are very important for the success of the ventricular assist device implantation process.

Computational Prediction of the Combined Effect of CRT and LVAD on Cardiac Electromechanical Delay in LBBB and RBBB

Two case reports showed that the combination of CRT and LVAD benefits the end-stage heart failure patients with prolonged QRS interval significantly. In one of the reports, the patient had the LVAD removed due to the recovery of the heart function. However, the quantification of the combined devices has yet to be conducted. This study aimed at computationally predicting the effects of CRT-only or combined with LVAD on electromechanical behaviour in the failing ventricle with left bundle branch blocked (LBBB) and right bundle branch blocked (RBBB) conditions. The subjects are normal sinus rhythm, LBBB, RBBB, LBBB with CRT-only, RBBB with CRT-only, LBBB with CRT + LVAD, and RBBB with CRT + LVAD. The results showed that the CRT-only shortened the total electrical activation time (EAT) in the LBBB and RBBB conditions by 20.2% and 17.1%, respectively. The CRT-only reduced the total mechanical activation time (MAT) and electromechanical delay (EMD) of the ventricle under LBBB by 21.3% and 10.1%, respectively. Furthermore, the CRT-only reduced the contractile adenosine triphosphate (ATP) consumption by 5%, increased left ventricular (LV) pressure by 6%, and enhanced cardiac output (CO) by 0.2 L/min under LBBB condition. However, CRT-only barely affects the ventricle under RBBB condition. Under the LBBB condition, CRT + LVAD increased LV pressure and CO by 10.5% and by 0.9 L/min, respectively. CRT + LVAD reduced ATP consumption by 15%, shortened the MAT by 23.4%, and shortened the EMD by 15.2%. In conclusion, we computationally predicted and quantified that the CRT + LVAD implementation is superior to CRT-only implementation particularly in HF with LBBB condition.

Effect of concomitant mitral valve procedures for severe mitral regurgitation during left ventricular assist device implantation

The effect of performing a concomitant mitral valve procedure (MVP) during continuous-flow left ventricular assist device (CF-LVAD) implantation has been reported for patients with moderate-to-severe mitral regurgitation (MR), but moderate MR is less of a clinical concern for CF-LVAD patients. There is a paucity of reports focusing on patients with severe MR. Thus, the purpose of this study was to analyze the effect of performing a concomitant MVP during CF-LVAD implantation in patients with severe preoperative MR. Between November 2003 and March 2016, 526 patients underwent primary implantation of a CF-LVAD at our center. Patients with severe MR who underwent a concomitant MVP were compared to those who did not in regard to overall survival, perioperative complications, postoperative echocardiography data, bridge-to-transplantation success, and CF-LVAD explantation. Of the 108 patients with severe MR, 26 underwent a concomitant MVP and 82 did not. These groups showed no difference in survival (p = 0.61). Additionally, the two groups had similar rates of postoperative right heart failure (p = 0.69) and readmissions (p = 0.42). The 24-month follow-up echocardiography results were also similar. Furthermore, the groups showed no difference in bridge-to-cardiac transplantation success (30.0% vs 25.0%, p = 0.80) or CF-LVAD explantation rates (0.0% vs 0.0%. p = 1.0). Our findings suggest that patients with severe MR who undergo a MVP during CF-LVAD implantation do not have superior outcomes to those who do not. However, assessments of other outcomes may show some benefits to performing concomitant MVPs.

Long-Term Continuous-Flow Left Ventricular Assist Device Support After Left Ventricular Outflow Tract Closure

Aortic valve insufficiency can be addressed during continuous-flow left ventricular assist device (CF-LVAD) implantation by performing aortic valve repair or replacement, or patch closure of the left ventricular outflow tract (LVOT). However, few studies have examined the safety of long-term CF-LVAD support after LVOT closure. From November 2003 through March 2016, 16 patients with advanced chronic heart failure underwent CF-LVAD implantation and concomitant LVOT closure for severe aortic insufficiency. We compared their long-term outcomes with those of 510 CF-LVAD recipients without concomitant LVOT closure. Total support time was 26.1 patient-years in the LVOT-closure group and 938.6 patient-years in the CF-LVAD-only group. Survival at 30 days, 6 months, 1 year, and 2 years was similar for CF-LVAD-only patients (90.4%, 80.6%, 74.3%, 67.5%) and LVOT-closure patients (81.3%, 81.3%, 75.0%, 68.8%; p = 0.59). There were no deaths related to LVOT closure. The event rate per patient-year for neurologic dysfunction (ND) was 0.23 in the LVOT-closure group (6 ND events) and 0.20 in the CF-LVAD-only group (136 ND events; p = 0.97). We conclude that for select patients with aortic insufficiency who are undergoing CF-LVAD implantation, LVOT closure produces acceptable outcomes and, therefore, is a viable option.

Frequency and Consequences of Right-Sided Heart Failure After Continuous-Flow Left Ventricular Assist Device Implantation

Postoperative right-sided heart failure (RHF) is a common complication after continuous-flow left ventricular assist device implantation. Studies have examined RHF in the perioperative period, but few have assessed late-onset RHF. We analyzed the incidence of early and late RHF in patients with HeartMate II and HeartWare left ventricular assist devices and associated morbidity, mortality, and independent predictors of RHF. We retrospectively analyzed records of 526 patients with chronic heart failure who underwent continuous-flow left ventricular assist device implantation; 147 (27.9%) developed RHF (early RHF, n = 87, 16.5%; late RHF, n = 74, 14.4%). We examined demographics, postoperative complications, and long-term survival rate. Patients with RHF or late RHF had higher mortality (p <0.001) than those without RHF. Patients with RHF had a higher incidence of acute kidney injury (20.4% vs 11.9%, p = 0.01). Device type did not affect the incidence of early, late, or overall RHF. Patients with severe RHF requiring right ventricular assist device support had a low success of bridge to transplantation (11.1% vs 33.3%, p = 0.02). In Cox regression models, RHF was an independent predictor of mortality (hazard ratio = 1.69, 95% confidence interval = 1.28 to 2.22, p <0.001), but no predictive variables of RHF were identified. RHF was significantly associated with increased mortality and a higher incidence of postoperative acute kidney injury. RHF decreased the success rate of bridging patients to transplantation when a right ventricular assist device was required.

Prevention and Treatment of Thrombotic and Hemorrhagic Complications in Patients Supported by Continuous-Flow Left Ventricular Assist Devices

PURPOSE OF REVIEW

The purpose of this review is to describe the current knowledge in prevention and treatment of thrombotic (pump thrombosis and ischemic stroke) and bleeding (gastrointestinal and hemorrhagic stroke) complications in patients supported by continuous-flow left ventricular assist devices (CF-LVAD).

RECENT FINDINGS

Left ventricular assist devices (LVADs) are now widely used for the management of end-stage heart failure. Unfortunately, in spite of the indisputable positive impact LVADs have on patients, the frequency and severity of complications are limitations of this therapy. Stroke, pump thrombosis, and gastrointestinal bleeding are among the most serious and frequent complications in these patients. The balance between hemorrhagic and thrombotic complications in patients supported with CF-LVAD is difficult as most patients do not necessarily fit a "bleeder" or a "clotter" profile but rather move from one side to the other of the thrombotic/bleeding spectrum. Further research is necessary to better understand the risk factors and mechanisms involved in the development of these complications.

Computational analysis of the effect of mitral and aortic regurgitation on the function of ventricular assist devices using 3D cardiac electromechanical model

Valvular insufficiency affects cardiac responses and the pumping efficacy of left ventricular assist devices (LVADs) when patients undergo LVAD therapy. Knowledge of the effect of valvular regurgitation on the function of LVADs is important when treating heart failure patients. The goal of this study was to examine the effect of valvular regurgitation on the ventricular mechanics of a heart under LVAD treatment and the pumping efficacy of an LVAD using a computational model of the cardiovascular system. For this purpose, a 3D electromechanical model of failing ventricles in a human heart was coupled with a lumped-parameter model of valvular regurgitation and an LVAD-implanted vascular system. We used the computational model to predict cardiac responses with respect to the severity of valvular regurgitation in the presence of LVAD treatment. An LVAD could reduce left ventricle (LV) pressure (up to 34%) and end-diastolic ventricular volume (up to 80%) and maintain cardiac output at the estimated flow rate from the LVAD under the condition of mitral regurgitation (MR); however, the opposite would occur under the condition of aortic regurgitation (AR). Considering these physiological responses, we conclude that AR, and not MR, diminishes the pumping function of LVADs.

Left ventricular outflow tract closure during LVAD implantation: 2 cases of patients supported for over 6 years

We previously reported a series of 5 patients with advanced heart failure and aortic insufficiency (AI) who underwent concomitant left ventricular outflow tract (LVOT) closure at the time of continuous-flow left ventricular assist device (CF-LVAD) implantation. Although this technique of treating AI has been shown to be effective in the short term, its long-term durability has not been well studied. Here, we report the long-term outcomes of two patients with severe AI who underwent LVOT closure at the time of CF-LVAD implantation. Each of the two patients survived for more than 6 years without any complications related to LVOT closure.

Accuracy of Seattle Heart Failure Model and HeartMate II Risk Score in Non-Inotrope-Dependent Advanced Heart Failure Patients: Insights From the ROADMAP Study (Risk Assessment and Comparative Effectiveness of Left Ventricular Assist Device and Medical Management in Ambulatory Heart Failure Patients)

BACKGROUND

Timing of left ventricular assist device (LVAD) implantation in advanced heart failure patients not on inotropes is unclear. Relevant prediction models exist (SHFM [Seattle Heart Failure Model] and HMRS [HeartMate II Risk Score]), but use in this group is not established.

METHODS AND RESULTS

ROADMAP (Risk Assessment and Comparative Effectiveness of Left Ventricular Assist Device and Medical Management in Ambulatory Heart Failure Patients) is a prospective, multicenter, nonrandomized study of 200 advanced heart failure patients not on inotropes who met indications for LVAD implantation, comparing the effectiveness of HeartMate II support versus optimal medical management. We compared SHFM-predicted versus observed survival (overall survival and LVAD-free survival) in the optimal medical management arm (n=103) and HMRS-predicted versus observed survival in all LVAD patients (n=111) using Cox modeling, receiver-operator characteristic (ROC) curves, and calibration plots. In the optimal medical management cohort, the SHFM was a significant predictor of survival (hazard ratio=2.98; P<0.001; ROC area under the curve=0.71; P<0.001) but not LVAD-free survival (hazard ratio=1.41; P=0.097; ROC area under the curve=0.56; P=0.314). SHFM showed adequate calibration for survival but overestimated LVAD-free survival. In the LVAD cohort, the HMRS had marginal discrimination at 3 (Cox P=0.23; ROC area under the curve=0.71; P=0.026) and 12 months (Cox P=0.036; ROC area under the curve=0.62; P=0.122), but calibration was poor, underestimating survival across time and risk subgroups.

CONCLUSIONS

In non-inotrope-dependent advanced heart failure patients receiving optimal medical management, the SHFM was predictive of overall survival but underestimated the risk of clinical worsening and LVAD implantation. Among LVAD patients, the HMRS had marginal discrimination and underestimated survival post-LVAD implantation.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01452802.

Combined Endoscopic and Surgical Treatment of Severe Gastrointestinal Bleeding in a Patient with Heart Assist Device under Therapeutic Anticoagulation

Gastrointestinal (GI) bleeding is a common complication after heart assist device placement. Reasons for bleeding are multifactorial. Endoscopic therapy is the treatment of choice, whereas invasive procedures are avoided in these critically ill patients. We present the case of a 65-year-old male patient experiencing severe GI bleeding after left ventricular assist device (LVAD) and right ventricular assist device (RVAD) placement with therapeutic anticoagulation. Endoscopically, multiple gastric bleeding sources were found but could not be treated effectively due to a large blood clot. A combined endoscopic and surgical treatment was initiated, including gastrotomy for blood clot removal, surgical transgastric suturing, endoscopic over-the-scope clip (OTSC) placement and hemospray application. Postoperative endoscopic visualization showed effective bleeding control. The patient unfortunately died due to causes unrelated to the treatment. This case shows that a minimal invasive combination of endoscopic and surgical techniques can be an alternative treatment for severe upper GI bleeding in critically ill and anticoagulated patients.

Left Ventricular Assist Device as a Bridge to Recovery for Patients With Advanced Heart Failure

BACKGROUND

Left ventricular assist devices (LVADs) have been used as an effective therapeutic option in patients with advanced heart failure, either as a bridge to transplantation, as destination therapy, or in some patients, as a bridge to recovery.

OBJECTIVES

This study evaluated whether patients undergoing an LVAD bridge-to-recovery protocol can achieve cardiac and physical functional capacities equivalent to those of healthy controls.

METHODS

Fifty-eight male patients-18 implanted with a continuous-flow LVAD, 16 patients with LVAD explanted (recovered patients), and 24 heart transplant candidates (HTx)-and 97 healthy controls performed a maximal graded cardiopulmonary exercise test with continuous measurements of respiratory gas exchange and noninvasive (rebreathing) hemodynamic data. Cardiac function was represented by peak exercise cardiac power output (mean arterial blood pressure × cardiac output) and functional capacity by peak exercise O₂ consumption.

RESULTS

All patients demonstrated a significant exertional effort as demonstrated with the mean peak exercise respiratory exchange ratio >1.10. Peak exercise cardiac power output was significantly higher in healthy controls and explanted LVAD patients compared with other patients (healthy 5.35 ± 0.95 W; explanted 3.45 ± 0.72 W; LVAD implanted 2.37 ± 0.68 W; and HTx 1.31 ± 0.31 W; p < 0.05), as was peak O₂ consumption (healthy 36.4 ± 10.3 ml/kg/min; explanted 29.8 ± 5.9 ml/kg/min; implanted 20.5 ± 4.3 ml/kg/min; and HTx 12.0 ± 2.2 ml/kg/min; p < 0.05). In the LVAD explanted group, 38% of the patients achieved peak cardiac power output and 69% achieved peak O₂ consumption within the ranges of healthy controls.

CONCLUSIONS

The authors have shown that a substantial number of patients who recovered sufficiently to allow explantation of their LVAD can even achieve cardiac and physical functional capacities nearly equivalent to those of healthy controls.

Comparison of Mechanical Circulatory Support by the Use of Pulsatile Left Ventricular Assist Devices Polvad MEV and Continuous Flow Heart Ware and Heart Mate II in a Single-Center Experience

BACKGROUND

Mechanical circulatory support is increasingly used in patients with heart failure as a bridge to transplant or recovery. Results of use the Polish POLVAD MEV pulsatile circulatory support system and its comparison with novel devices never was done. We compared the course of patients with left ventricular circulatory support (left ventricular assist device [LVAD]) supported by POLVAD MEV or continuous flow devices Heart Mate II (HM II) and Heart Ware (HW) in single-center cohort.

METHODS

We retrospectively reviewed 44 patients who underwent Polvad Mev (group P; n = 24 [21M/3F]) or HW or HM II (group C; n = 20 [20M/0F]) implantation between April 2007 and February 2014. Patients were in INTERMACS 1 (6 in group P and 1 in group C) or 2. Preimplant demographics, and perioperative and postoperative clinical outcomes were reviewed between groups. We analyzed baseline signs of heart failure, comorbidities, complications, and the 30- and 90-day results.

RESULTS

Among the groups, age, gender, weight, and cause of heart failure were comparable. Patients in group C suffered more frequently from hypercholesterolemia preoperatively. Patients in group P had more pulmonary complications (7 vs 0) after LVAD implantation and stay longer on intensive care unit than patients in group C (17.61 ± 16.96 vs 9.56 ± 9.42; P = .047). After exclusion, INTERMACS 1 patients it was not significant (14.8 ± 10.8 vs 9.8 ± 9.6 days; P = .065), the 30- and 90-day mortality was comparable.

CONCLUSIONS

Implantation of pulsatile POLVAD MEV and continuous flow devices as LVAD support provides comparable results. A greater number of complications in group P can cause increased mortality over a longer observation period.

Optimal timing of same-admission orthotopic heart transplantation after left ventricular assist device implantation

AIM

To investigate the impact of timing of same-admission orthotopic heart transplant (OHT) after left ventricular assist device (LVAD) implantation on in-hospital mortality and post-transplant length of stay.

METHODS

Using data from the Nationwide Inpatient Sample from 1998 to 2011, we identified patients 18 years of age or older who underwent implantation of a LVAD and for whom the procedure date was available. We calculated in-hospital mortality for those patients who underwent OHT during the same admission as a function of time from LVAD to OHT, adjusting for age, sex, race, household income, and number of comorbid diagnoses. Finally, we analyzed the effect of time to OHT after LVAD implantation on the length of hospital stay post-transplant.

RESULTS

Two thousand and two hundred patients underwent implantation of a LVAD in this cohort. One hundred and sixty-four (7.5%) patients also underwent OHT during the same admission, which occurred on average 32 d (IQR 7.75-66 d) after LVAD implantation. Of patients who underwent OHT, patients who underwent transplantation within 7 d of LVAD implantation (“early”) experienced increased in-hospital mortality (26.8% vs 12.2%, P = 0.0483) compared to patients who underwent transplant after 8 d (“late”). There was no statistically significant difference in age, sex, race, household income, or number of comorbid diagnoses between the early and late groups. Post-transplant length of stay after LVAD implantation was also not significantly different between patients who underwent early vs late OHT.

CONCLUSION

In this cohort of patients who received LVADs, the rate of in-hospital mortality after OHT was lower for patients who underwent late OHT (at least 8 d after LVAD implantation) compared to patients who underwent early OHT. Delayed timing of OHT after LVAD implantation did not correlate with longer hospital stays post-transplant.

Perioperative onset of acquired von Willebrand syndrome: Comparison between HVAD, HeartMate II and on-pump coronary bypass surgery

OBJECTIVES

Acquired von Willebrand syndrome (AvWS) is associated with postoperative bleeding complications in patients with continuous flow left ventricular assist devices (CF-LVADs). The aim of this study is to analyze the perioperative vWF profile comparing an axial pump (HMII) to a centrifugal pump (HVAD) regarding the correlation between perioperative occurrence of AvWS, early- and late-postoperative bleeding events.

METHODS

From July 2013 until March 2015 blood samples of 33 patients (12 HMII/ 8 HVAD/ 13 controls) were prospectively collected at 12 different time points and analyzed for the vWF antigen (vWF:Ag), its activity (vWF:Ac) and the vWF:Ac/vWF:Ag-ratio (vWF:ratio). The follow up period for postoperative bleeding events was from July 2013 until July 2016.

RESULTS

Postoperatively, there was no difference in the vWF-profile between HVAD and HMII groups. However, a subgroup of patients already had significantly lower vWF:ratios preoperatively. Postoperatively, both CF-LVAD groups presented significantly lower vWF:ratios compared to the control group. Bleeding events per patient-year did not differ between the two groups (HMII vs. HVAD: 0.67 vs. 0.85, p = 0.685). We detected a correlation between vWF:ratio <0.7at LVAD-start (r = -0.583, p = 0.006) or at the end of surgery (r = -0.461, p = 0.035) and the occurrence of pericardial tamponade. In the control group, the drop in both vWF:Ag and vWF:Ac recovered immediately postoperatively above preoperative values.

CONCLUSION

A subgroup of patients with end-stage heart failure already suffers AvWS preoperatively. In both CF-LVAD groups, AvWS begins immediately after surgery. Intraoperative vWF:ratios <0.7 correlate with higher incidences of pericardial tamponade and re-operation. The presumably dilutive effect of the heart lung machine on vWF vanishes immediately at the end of surgery, possibly as part of an acute-phase response.

Continuous-Flow Left Ventricular Assist Device Support Improves Myocardial Supply:Demand in Chronic Heart Failure

Continuous-flow left ventricular assist devices (CF LVADs) are rotary blood pumps that improve mean blood flow, but with potential limitations of non-physiological ventricular volume unloading and diminished vascular pulsatility. In this study, we tested the hypothesis that left ventricular unloading with increasing CF LVAD flow increases myocardial flow normalized to left ventricular work. Healthy (n = 8) and chronic ischemic heart failure (IHF, n = 7) calves were implanted with CF LVADs. Acute hemodynamics and regional myocardial blood flow were measured during baseline (LVAD off, clamped), partial (2-4 L/min) and full (>4 L/min) LVAD support. IHF calves demonstrated greater reduction of cardiac energy demand with increasing LVAD support compared to healthy calves, as calculated by rate-pressure product. Coronary artery flows (p < 0.05) and myocardial blood flow (left ventricle (LV) epicardium and myocardium, p < 0.05) decreased with increasing LVAD support in normal calves. In the IHF model, blood flow to the septum, LV, LV epicardium, and LV myocardium increased significantly with increasing LVAD support when normalized to cardiac energy demand (p < 0.05). In conclusion, myocardial blood flow relative to cardiac demand significantly increased in IHF calves, thereby demonstrating that CF LVAD unloading effectively improves cardiac supply and demand ratio in the setting of ischemic heart failure.

The future of mechanical circulatory support for advanced heart failure

PURPOSE OF REVIEW

Mechanical circulatory support (MCS) has become the main focus of heart replacement therapy for end stage heart failure patients. Advances in technology are moving towards miniaturization, biventricular support devices, complete internalization, improved hemocompatibility profiles, and responsiveness to cardiac loading conditions. This review will discuss the recent advances and investigational devices in MCS for advanced heart failure.

RECENT FINDINGS

The demand for both short-term and long-term durable devices for advanced heart failure is increasing. The current devices are still fraught with an unacceptably high incidence of gastrointestinal bleeding and thromboembolic and infectious complications. New devices are on the horizon focusing on miniaturization, versatility for biventricular support, improved hemocompatibility, use of alternate energy sources, and incorporation of continuous hemodynamic monitoring.

SUMMARY

The role for MCS in advanced heart replacement therapy is steadily increasing. With the advent of newer generation devices on the horizon, the potential exists for MCS to surpass heart transplantation as the primary therapy for advanced heart failure.

Effect of Gender on the Risk of Neurologic Events and Subsequent Outcomes in Patients With Left Ventricular Assist Devices

Previous studies have shown that women with continuous-flow left ventricular assist devices (LVADs) are at greater risk of neurologic events. However, the relation between neurologic events and subsequent outcomes by gender is not well understood. We aimed to identify gender differences in the risk of neurologic events in patients with LVAD and the impact of time-dependent neurologic event on all-cause mortality by gender. Our study included 34 women and 157 men who received a HeartMate II LVAD at the University of Rochester Medical Center, Rochester, New York, from May 5, 2008, to June 5, 2014. Neurologic event was defined as a transient ischemic attack or cerebrovascular accident (hemorrhagic or ischemic). During a median follow-up of 25 months, 16 women (47%) and 20 men (13%) had neurologic events. Among patients with neurologic events, 7 women (44%) and 9 men (45%) died. Women had a 4.67-fold greater risk of neurologic events (hazard ratio [HR] 4.67, 95% confidence interval [CI] 2.26 to 9.66, p <0.001) compared with men. Women with neurologic events had an increased risk of all-cause mortality compared to women without neurologic event (HR 4.84, 95% CI 1.33 to 17.55, p = 0.017). Similarly, men with neurologic events had an increased risk of all-cause mortality compared to men without neurologic event (HR 4.20, 95% CI 1.93 to 9.17, p <0.001, interaction p = 0.854). In conclusion, among patients with LVAD, women are at greater risk of neurologic event compared to men. Both women and men after LVAD have similar high risk of all-cause mortality after neurologic events.

Arterial pulsatility under phasic left ventricular assist device support

The aim of this study is to understand whether the phasic Continuous Flow Left Ventricular Assist Device (CF-LVAD) support would increase the arterial pulsatility. A Micromed DeBakey CF-LVAD was used to apply phasic support in an ex-vivo experimental platform. CF-LVAD was operated over a cardiac cycle by phase-shifting the pulsatile pump control with respect to the heart cycle, in 0.05 s increments in each experiment. The pump flow rate was selected as the control variable and a reference model was used to operate the CF-LVAD at a pulsatile speed. Arterial pulse pressure was the highest (9 mmHg) when the peak pump flow is applied at the peak systole under varying speed CF-LVAD support over a cardiac cycle while it was the lowest (2 mmHg) when the peak pump flow was applied in the diastolic phase. The mean arterial pressure and mean CF-LVAD output were the same in each experiment while arterial pulse pressure and pulsatility index varied depending on the phase of reference pump flow rate signal. CF-LVAD speed should be synchronized considering the timing of peak systole over a cardiac cycle to increase the arterial pulsatility. Moreover, it is possible to decrease the arterial pulsatility under counter-pulsating CF-LVAD support.

DURABLE MECHANICAL CIRCULATION SUPPORT AS AN ALTERNATIVE TO HEART TRANSPLANTATION

In the review a comparative analysis of the treatment of end-stage chronic heart failure using heart transplantation and durable mechanical circulatory is conducted. It shows the main advantages and limitations of heart transplantation and the prospects of application of durable mechanical circulatory support technology. The main directions of this technology, including two-stage heart transplant (bridge to transplant – BTT), assisted circulation for myocardial recovery (bridge to recovery – BTR) and implantation of an auxiliary pump on a regular basis (destination therapy, DT). 

The hemodynamic effects of the LVAD outflow cannula location on the thrombi distribution in the aorta: A primary numerical study

Although a growing number of patients undergo LVAD implantation for heart failure treatment, thrombi are still the devastating complication for patients who used LVAD. LVAD outflow cannula location and thrombi generation sources were hypothesized to affect the thrombi distribution in the aorta. To test this hypothesis, numerical studies were conducted by using computational fluid dynamic (CFD) theory. Two anastomotic configurations, in which the LVAD outflow cannula is anastomosed to the anterior and lateral ascending aortic wall (named as anterior configurations and lateral configurations, respectively), are designed. The particles, whose sized are same as those of thrombi, are released at the LVAD output cannula and the aortic valve (named as thrombiP and thrombiL, respectively) to calculate the distribution of thrombi. The simulation results demonstrate that the thrombi distribution in the aorta is significantly affected by the LVAD outflow cannula location. In anterior configuration, the thrombi probability of entering into the three branches is 23.60%, while that in lateral configuration is 36.68%. Similarly, in anterior configuration, the thrombi probabilities of entering into brachiocephalic artery, left common carotid artery and left subclavian artery, is 8.51%, 9.64%, 5.45%, respectively, while that in lateral configuration it is 11.39%, 3.09%, 22.20% respectively. Moreover, the origins of thrombi could affect their distributions in the aorta. In anterior configuration, the thrombiP has a lower probability to enter into the three branches than thrombiL (12% vs. 25%). In contrast, in lateral configuration, the thrombiP has a higher probability to enter into the three branches than thrombiL (47% vs. 35%). In brief, the LVAD outflow cannula location significantly affects the distribution of thrombi in the aorta. Thus, in the clinical practice, the selection of outflow location of LVAD and the risk of thrombi formed in the left ventricle should be paid more attention than before.