Aortic regurgitation in patients with a left ventricular assist device: A contemporary review

HeartMate 3 upgrade and aortic root replacement for severe aortic insufficiency and ventricular fibrillation

A 31-year-old woman with left ventricular (LV) assist device (LVAD) support presented with refractory ventricular arrhythmias attributed to severe aortic insufficiency and inadequate left ventricular offloading. The patient had a history of 2 prior pump exchanges in the setting of chronic polymicrobial driveline infections and prior transcatheter aortic valve implantation (TAVI). She underwent aortic valve replacement for management of her ventricular arrythmias. Due to her complicated surgical history, right heart failure, and prolonged cardiopulmonary bypass time the surgical aortic valve replacement and HeartMate 3 upgrade was complicated, but surgery was successful with subsequent termination of her ventricular arrythmias.

Impact of concomitant aortic valve replacement in patients with mild-to-moderate aortic valve regurgitation undergoing left ventricular assist device implantation: EUROMACS analysis

INTRODUCTION

Left ventricular assist device (LVAD) therapy may lead to an aortic regurgitation, limiting left ventricular unloading and causing adverse events. Whether concomitant aortic valve replacement may improve outcomes in patients with preoperative mild-to-moderate aortic regurgitation remains unclear.

METHODS

A retrospective propensity score-matched analysis of adult patients with preoperative mild-to-moderate aortic regurgitation undergoing durable LVAD implantation between 01/01/2011 and 30/11/2021 was performed. Patients undergoing concomitant valve surgery other than biological aortic valve replacement were excluded, resulting in 77 with concomitant biological aortic valve replacement and 385 without.

RESULTS

Following 1:1 propensity score matching, two groups of 55 patients with and without biological aortic valve replacement were obtained, (mean age 59 ± 11 years, 92% male, 59.1% HeartWare). Aortic regurgitation was mild in 72.7% and 76.4% and moderate in 27.3% and 23.6% in non-replacement and replacement cohorts respectively. The 30-day survival was 89.1% vs. 85.5% (p = 0.59), 1-year survival 69.1% vs. 56.4% (p = 0.19), and 2-year survival 61.8% vs. 47.3% (p = 0.10) in the non-replacement and replacement groups, respectively. After a mean follow-up of 1.2 years, non-replacement patients had a higher incidence of pump thrombosis (11 [20%] vs. 3 [5.5%], p = 0.022) and fewer major bleedings (2 [3.6%] vs. 11 [20%], p = 0.008).

CONCLUSION

Compared with those treated conservatively, patients with mild-to-moderate aortic regurgitation undergoing concomitant aortic valve replacement during LVAD implantation have a similar survival up to 2 years on support. Patients with concomitant valve replacement had a higher risk of bleeding complications but fewer pump thromboses.

Aortic regurgitation in left ventricular assist device patients: Does aortic root dilatation contribute to valve incompetence?

BACKGROUND

Aortic regurgitation (AR) is a known complication after left ventricular assist device (LVAD) implantation potentially leading to recurrent heart failure. Possible pathomechanisms include valvular pathologies and aortic root dilatation. We assessed aortic root dimensions in a group of consecutive LVAD patients who received HeartMate 3.

METHODS

Since 11/2015, we identified 68 patients with no or mild AR at the time of HeartMate 3 implantation who underwent serial echocardiography to assess AR and aortic root dimensions (annulus, sinus, and sinotubular junction). Median follow-up was 40 months (2-94 months). Results were correlated with clinical outcomes.

RESULTS

Patients were 60 ± 10 years old, predominantly male (88%) and 35% presented in preoperative critical condition as defined by INTERMACS levels 1 and 2. During follow-up, 23 patients developed AR ≥ II (34%). Actuarial incidence was 8% at 1 year, 29% at 3 years and 41% at 5 years. Echocardiography revealed practically stable root dimensions at the latest follow-up compared to the preoperative state (annulus: 23 ± 3 mm vs. 23 ± 2 mm, sinus: 32 ± 4 mm vs. 33 ± 3 mm, sinotubular junction: 27 ± 3 mm vs. 28 ± 3 mm), irrespective of the development of AR. Serial CT angiograms were performed in 13 patients to confirm echocardiographic findings. Twenty-one patients died during LVAD support leading to a 5-year survival of 71%, showing no difference between patients with and without AR ≥ II (p = 0.573).

CONCLUSIONS

At least moderate AR develops over time in a substantial fraction of patients (one-third over 3 years). The mechanism does not seem to be related to dilatation of the aortic annulus or root.

Validity and Accuracy of the Derived Left Ventricular End-Diastolic Pressure in Impella 5.5

BACKGROUND

Consensus regarding on-support evaluation and weaning concepts from Impella 5.5 support is scarce. The derived left ventricular end-diastolic pressure (dLVEDP), estimated by device algorithms, is a rarely reported tool for monitoring the weaning process. Its validation and clinical accuracy have not been studied in patients. We assess dLVEDP's accuracy in predicting pulmonary capillary wedge pressure (PCWP) and propose a corrective equation.

METHODS

We included 29 consecutive patients treated with Impella 5.5: 12 in a generation cohort and 17 in a validation cohort. dLVEDP and PCWP were measured 5-fold every 8 hours during support, totaling 698 series with 3490 measurements. Variables such as Impella 5.5 performance level, heart rhythm, pacemaker settings, sex, mechanical ventilation, and body mass index were recorded. Linear regression was used to correct dLVEDP-PCWP discrepancies. Analysis included Bland-Altman plots, linear regression, histograms, and violin plots.

RESULTS

The raw dLVEDP and PCWP data did not coincide satisfactorily. The Impella 5.5 dLVEDP overestimation was 3.5±1.5 mm Hg (mean±SD), increasing with higher pressures and unaffected by cardiac rhythm, mechanical ventilation, and performance levels. Statistical correction using the formula modified dLVEDP=-0.457+(1-sex[1=male, 0=female])×0.719-0.0496× body mass index+1.015×body surface area+0.811×dLVEDP significantly reduced the overestimation (P<0.01) to 0.0±1.2 mm Hg.

CONCLUSIONS

dLVEDP, calculated by the Impella 5.5 Smart Algorithm, is a feasible and effective tool for continuously monitoring PCWP at performance levels 3 to 9. Correction of dLVEDP by using the described equation further enhances its accuracy. Hence, hemodynamic surveillance via dLVEDP may aid in managing and weaning temporary microaxial support, potentially reducing the need for continuous monitoring with a Swan-Ganz catheter.

In Vitro Analysis of Left Ventricular Assist Device Outflow Graft Orientations and Their Effect on Aortic Hemodynamics

Continuous-flow left ventricular assist devices have become an important treatment option for patients with advanced heart failure. However, adverse hemodynamic effects as consequence of an altered blood flow within the aorta and the aortic root remain a topic of concern. In this work, we investigated the influence of the outflow graft orientation on the hemodynamic profile and flow parameters within the thoracic aorta. Aortic models with different outflow graft orientations were designed and three-dimensional (3D) printed to mimic common implantation configurations and were integrated into a pulsatile mock circulatory flow loop. Assist device function was achieved using a rotary pump, replicating nonpulsatile, continuous support flows of 1-5 L/min. Flow velocity, wall shear stress, and pressure gradients were investigated for each configuration using sonography and four-dimensional (4D) flow magnetic resonance imaging. Mean wall shear stresses measured in 4D flow software were lowest for a graft inclination angle of 45°. Streamline visualization revealed areas of nonuniform, retrograde, and vortex flow in all models but most prominent for the aortic model with an outflow graft inclination of 60°. The insights gained from this research may aid in understanding clinical outcomes following assist device implantation and long-term mechanical circulatory support.

Myval Transcatheter Heart Valve: The Future of Transcatheter Valve Replacement and Significance in Current Timeline

The Myval is a balloon-expandable transcatheter heart valve (THV) developed by Meril Life Sciences Pvt. Ltd. (Vapi, Gujarat, India) that has an innovative operator-friendly design that aids in improving deliverability and features precise deployment. Various clinical studies demonstrate its effectiveness and safety, making it a promising choice in valvular interventions. Myval has been successfully utilized as a transcatheter aortic valve implantation (TAVI) device in cases with conduction disturbances, bicuspid aortic valve anatomy, non-calcified aortic regurgitation, dysfunctional stenosed right ventricular outflow tract (RVOT) conduits, pulmonary valve replacement, mitral valve replacement, and valve-in-valve and valve-in-ring implantation procedures. Myval's diverse sizes are also of key importance in complex cases of large annuli and complex anatomy. Further long-term studies are needed to consolidate these results. Its introduction signifies a significant advancement in cardiology, aiming to enhance patient outcomes and quality of life. In the present review, we provide an update on new-generation Myval THV series and review the available clinical data published to date with an emphasis on diverse use in specific clinical scenarios.

Structural heart transcatheter interventions in orthotopic cardiac transplant and left ventricular assist devices recipients: A nationwide study

BACKGROUND

The current incidence and outcomes of structural transcatheter procedures in heart transplant (HTx) recipients and left-ventricular assist devices (LVAD) carriers is unknown.

AIMS

To provide insights on structural transcatheter procedures performed across HTx and LVAD patients in Spain.

METHODS

Multicenter, ambispective, observational nationwide registry.

RESULTS

Until May/2023, 36 percutaneous structural interventions were performed (78% for HTx and 22% for LVAD) widely varying among centers (0%-1.4% and 0%-25%, respectively). Percutaneous mitral transcatheter edge-to-edge (TEER) was the most common (n = 12, 33.3%), followed by trancatheter aortic valve replacement (n = 11, 30.5%), and tricuspid procedures (n = 9, 25%). Mitral TEER resulted in mild residual mitral regurgitation in all but one case, mean gradient was <5 mmHg in 75% of them at 1-year, with no mortality and 8.3% re-admission rate. Tricuspid TEER resulted in 100% none/mild residual regurgitation with a 1-year mortality and readmission rates of 22% and 28.5%, respectively. Finally, trancatheter aortic valve replacement procedures (n = 8 in LVADs due to aortic regurgitation and n = 3 in HTx), were successful in all cases with one prosthesis degeneration leading to severe aortic regurgitation at 1-year, 18.2% mortality rate and no re-admissions. Globally, major bleeding rates were 7.9% and 12.5%, thromboembolic events 3.7% and 12.5%, readmissions 37% and 25%, and mortality 22% and 25%, in HTx and LVADs respectively. No death was related to the implanted transcatheter device.

CONCLUSIONS

Most centers with HTx/LVAD programs perform structural percutaneous procedures but with very inconsistent incidence. They were associated with good safety and efficacy, but larger studies are required to provide formal recommendations.

When all Else Fails, Try This: The HeartMate III Left Ventricle Assist Device

Heart failure (HF) is a progressive disease. It is estimated that more than 250,000 patients suffer from advanced HF with reduced ejection fraction refractory to medical therapy. With limited donor pool for heart transplant, continue flow left ventricle assist device (LVAD) is a lifesaving treatment option for patients with advanced HF. This review will provide an update on indications, contraindications, and associated adverse events for LVAD support with a summary of the current outcomes data.

Multimodality imaging for the evaluation and management of patients with long-term (durable) left ventricular assist devices

Left ventricular assist devices (LVADs) are gaining increasing importance as therapeutic strategy in advanced heart failure (HF), not only as bridge to recovery or to transplant but also as destination therapy. Even though long-term LVADs are considered a precious resource to expand the treatment options and improve clinical outcome of these patients, these are limited by peri-operative and post-operative complications, such as device-related infections, haemocompatibility-related events, device mis-positioning, and right ventricular failure. For this reason, a precise pre-operative, peri-operative, and post-operative evaluation of these patients is crucial for the selection of LVAD candidates and the management LVAD recipients. The use of different imaging modalities offers important information to complete the study of patients with LVADs in each phase of their assessment, with peculiar advantages/disadvantages, ideal application, and reference parameters for each modality. This clinical consensus statement sought to guide the use of multimodality imaging for the evaluation of patients with advanced HF undergoing LVAD implantation.

Aortic regurgitation: from mechanisms to management

Aortic regurgitation (AR) is a common clinical disease associated with significant morbidity and mortality. Investigations based largely on non-invasive imaging are pivotal in discerning the severity of disease and its impact on the heart. Advances in technology have contributed to improved risk stratification and to our understanding of the pathophysiology of AR. Surgical aortic valve replacement is the predominant treatment. However, its use is limited to patients with an acceptable surgical risk profile. Transcatheter aortic valve implantation is an alternative treatment. However, this therapy remains in its infancy, and further data and experience are required. This review article on AR describes its prevalence, mechanisms, diagnosis and treatment.

Preoperative higher right ventricular stroke work index increases the risk of de novo aortic insufficiency after continuous-flow left ventricular assist device implantation

During continuous-flow left ventricular assist device (CF-LVAD) support, hemodynamic shear stress causes a burden on aortic valve (AV) leaflets, leading to de novo aortic insufficiency (AI). This study investigated the influence of preoperative hemodynamic parameters on de novo AI in CF-LVAD recipients. We reviewed 125 patients who underwent CF-LVAD implantation without concomitant AV surgery between 2005 and 2018. De novo AI was defined as moderate or severe AI in those with none or trivial preoperative AI. During mean 30 ± 16 months of CF-LVAD support, de novo AI-free rate was 86% and 67% at 1 and 2 years, respectively. Multivariable analysis showed that higher right ventricular stroke work index (RVSWI) (hazard ratio, 1.12 /g/m2/beat; 95% confidence interval, 1.00-1.20; p = 0.047) and trivial grade AI (hazard ratio, 2.8; 95% confidence interval, 1.2-6.4; p = 0.020) were independent preoperative risk factors for de novo AI. The longitudinal analysis using generalized mixed effects model showed that higher RVSWI was associated with continuous AV closure after LVAD implantation (Odd ratio, 1.20/g/m2/beat; 95% confidence interval, 1.00-1.43 /g/m2/beat; p = 0.047). Right heart catheterization revealed that preoperative RVSWI was positively correlated with postoperative pump flow index in patients with continuously closed AV (r = 0.44, p = 0.04, n = 22). Preoperative higher RVSWI was a significant risk factor for de novo AI following CF-LVAD implantation. In patients with preserved right ventricular function, postoperative higher pump flow may affect AI development via hemodynamic stress on the AV.

When all Else Fails, Try This: The HeartMate III Left Ventricle Assist Device

Heart failure (HF) is a progressive disease. It is estimated that more than 250,000 patients suffer from advanced HF with reduced ejection fraction refractory to medical therapy. With limited donor pool for heart transplant, continue flow left ventricle assist device (LVAD) is a lifesaving treatment option for patients with advanced HF. This review will provide an update on indications, contraindications, and associated adverse events for LVAD support with a summary of the current outcomes data.

Transcatheter aortic valve implantation for aortic regurgitation in HeartMate II supported patient using Myval THV: a case report

De novo aortic regurgitation (AR) presents a great challenge following left ventricular assist device (LVAD) implantation and requires valve replacement in some cases. Patients with LVAD are frequently those who underwent multiple previous sternotomies or suffer from multiple comorbidities. Thus, they are at high surgical risk for further sternotomy. Transcatheter aortic valve implantation (TAVI) previously approved for treatment of severe aortic stenosis is also used for this category of patients. Here, we report the case of a young female patient supported with heart mate II LVAD who presented with severe de novo AR. The patient was successfully treated with TAVI using Myval trancatheter heart valve (THV) in our center. To our knowledge, our patient is the first to be treated with such type of valve using TAVI procedure in LVAD supported patients.

How to Select Patients for Left Ventricular Assist Devices? A Guide for Clinical Practice

In recent years, a significant improvement in left ventricular assist device (LVAD) technology has occurred, and the continuous-flow devices currently used can last more than 10 years in a patient. Current studies report that the 5-year survival rate after LVAD implantation approaches that after a heart transplant. However, the outcome is influenced by the correct selection of the patients, as well as the choice of the optimal time for implantation. This review summarizes the indications, the red flags for prompt initiation of LVAD evaluation, and the principles for appropriate patient screening.

Acute heart failure and valvular heart disease: A scientific statement of the Heart Failure Association, the Association for Acute CardioVascular Care and the European Association of Percutaneous Cardiovascular Interventions of the European Society of Cardiology

Acute heart failure (AHF) represents a broad spectrum of disease states, resulting from the interaction between an acute precipitant and a patient's underlying cardiac substrate and comorbidities. Valvular heart disease (VHD) is frequently associated with AHF. AHF may result from several precipitants that add an acute haemodynamic stress superimposed on a chronic valvular lesion or may occur as a consequence of a new significant valvular lesion. Regardless of the mechanism, clinical presentation may vary from acute decompensated heart failure to cardiogenic shock. Assessing the severity of VHD as well as the correlation between VHD severity and symptoms may be difficult in patients with AHF because of the rapid variation in loading conditions, concomitant destabilization of the associated comorbidities and the presence of combined valvular lesions. Evidence-based interventions targeting VHD in settings of AHF have yet to be identified, as patients with severe VHD are often excluded from randomized trials in AHF, so results from these trials do not generalize to those with VHD. Furthermore, there are not rigorously conducted randomized controlled trials in the setting of VHD and AHF, most of the data coming from observational studies. Thus, distinct to chronic settings, current guidelines are very elusive when patients with severe VHD present with AHF, and a clear-cut strategy could not be yet defined. Given the paucity of evidence in this subset of AHF patients, the aim of this scientific statement is to describe the epidemiology, pathophysiology, and overall treatment approach for patients with VHD who present with AHF.

A case report: transfemoral transcatheter aortic valve replacement with a dedicated valve system for severe aortic regurgitation in a patient with a left ventricular assist device

Background

Up to 30% of patients with the left ventricular assist device (LVAD) develop moderate to severe aortic regurgitation (AR) within the first year. Surgical aortic valve replacement (SAVR) is the treatment of choice in patients with native AR. However, the high perioperative risk in patients with LVAD might prohibit surgery and choice of therapy is challenging.

Case summary

We report on a 55-year-old female patient with a severe AR 15 months after implantation of LVAD due to advanced heart failure (HF) as a consequence of ischaemic cardiomyopathy. Surgical aortic valve replacement was discarded due to high surgical risk. Thus, the decision was made to evaluate a transcatheter aortic valve replacement (TAVR) with the TrilogyXTä prothesis (JenaValve Technology, Inc., CA, USA). Echocardiographic and fluoroscopic control showed an optimal valve position with no evidence of valvular or paravalvular regurgitation. The patient was discharged 6 days later in a good general condition. At the 3-month follow-up, the patient showed noteworthy symptomatic improvement with no sign of HF.

Discussion

Aortic regurgitation is a common complication among advanced HF patients treated with LVADSystems and associated with a deterioration in the quality of life and worsen clinical prognosis. The treatment options are limited to percutaneous occluder devices, SAVR, off-label TAVR, and heart transplantation. With the approval of the TrilogyXT JenaValve system, a novel dedicated TF-TAVR option is now available. Our experience demonstrates the technical feasibility and safety of this system in patients with LVAD and AR resulting in effective elimination of AR.

Transcatheter valvular therapies in patients with left ventricular assist devices

Aortic, mitral and tricuspid valve regurgitation are commonly encountered in patients with continuous-flow left ventricular assist devices (CF-LVADs). These valvular heart conditions either develop prior to CF-LVAD implantation or are induced by the pump itself. They can all have significant detrimental effects on patients' survival and quality of life. With the improved durability of CF-LVADs and the overall rise in their volume of implants, an increasing number of patients will likely require a valvular heart intervention at some point during CF-LVAD therapy. However, these patients are often considered poor reoperative candidates. In this context, percutaneous approaches have emerged as an attractive "off-label" option for this patient population. Recent data show promising results, with high device success rates and rapid symptomatic improvements. However, the occurrence of distinct complications such as device migration, valve thrombosis or hemolysis remain of concern. In this review, we will present the pathophysiology of valvular heart disease in the setting of CF-LVAD support to help us understand the underlying rationale of these potential complications. We will then outline the current recommendations for the management of valvular heart disease in patients with CF-LVAD and discuss their limitations. Lastly, we will summarize the evidence related to transcatheter heart valve interventions in this patient population.

Patient-specific, echocardiography compatible flow loop model of aortic valve regurgitation in the setting of a mechanical assist device

Background

Aortic regurgitation (AR) occurs commonly in patients with continuous-flow left ventricular assist devices (LVAD). No gold standard is available to assess AR severity in this setting. Aim of this study was to create a patient-specific model of AR-LVAD with tailored AR flow assessed by Doppler echocardiography.

Methods

An echo-compatible flow loop incorporating a 3D printed left heart of a Heart Mate II (HMII) recipient with known significant AR was created. Forward flow and LVAD flow at different LVAD speed were directly measured and AR regurgitant volume (RegVol) obtained by subtraction. Doppler parameters of AR were simultaneously measured at each LVAD speed.

Results

We reproduced hemodynamics in a LVAD recipient with AR. AR in the model replicated accurately the AR in the index patient by comparable Color Doppler assessment. Forward flow increased from 4.09 to 5.61 L/min with LVAD speed increasing from 8,800 to 11,000 RPM while RegVol increased by 0.5 L/min (2.01 to 2.5 L/min).

Conclusions

Our circulatory flow loop was able to accurately replicate AR severity and flow hemodynamics in an LVAD recipient. This model can be reliably used to study echo parameters and aid clinical management of patients with LVAD.

Reciprocal interferences of the left ventricular assist device and the aortic valve competence

Patients suffering from end-stage heart failure tend to have high mortality rates. With growing numbers of patients progressing into severe heart failure, the shortage of available donors is a growing concern, with less than 10% of patients undergoing cardiac transplantation (CTx). Fortunately, the use of left ventricular assist devices (LVADs), a variant of mechanical circulatory support has been on the rise in recent years. The expansion of LVADs has led them to be incorporated into a variety of clinical settings, based on the goals of therapy for patients ailing from heart failure. However, with an increase in the use of LVADs, there are a host of complications that arise with it. One such complication is the development and progression of aortic regurgitation (AR) which is noted to adversely influence patient outcomes and compromise pump benefits leading to increased morbidity and mortality. The underlying mechanisms are likely multifactorial and involve the aortic root-aortic valve (AV) complex, as well as the LVAD device, patient, and other factors, all of them alter the physiological mechanics of the heart resulting in AV dysfunction. Thus, it is imperative to screen patients before LVAD implantation for AR, as moderate or greater AR requires a concurrent intervention at the time of LVADs implantation. No current strict guidelines were identified in the literature search on how to actively manage and limit the development and/or progression of AR, due to the limited information. However, some recommendations include medical management by targeting fluid overload and arterial blood pressure, along with adjusting the settings of the LVADs device itself. Surgical interventions are to be considered depending on patient factors, goals of care, and the underlying pathology. These interventions include the closure of the AV, replacement of the valve, and percutaneous approach via percutaneous occluding device or transcatheter aortic valve implantation. In the present review, we describe the interaction between AV and LVAD placement, in terms of patient management and prognosis. Also it is provided a comprehensive echocardiographic strategy for the precise assessment of AV regurgitation severity.

Aortic valve disorders and left ventricular assist devices

Aortic valve disorders are important considerations in advanced heart failure patients being evaluated for left ventricular assist devices (LVAD) and those on LVAD support. Aortic insufficiency (AI) can be present prior to LVAD implantation or develop de novo during LVAD support. It is usually a progressive disorder and can lead to impaired LVAD effectiveness and heart failure symptoms. Severe AI is associated with worsening hemodynamics, increased hospitalizations, and decreased survival in LVAD patients. Diagnosis is made with echocardiographic, device assessment, and/or catheterization studies. Standard echocardiographic criteria for AI are insufficient for accurate diagnosis of AI severity. Management of pre-existing AI includes aortic repair or replacement at the time of LVAD implant. Management of de novo AI on LVAD support is challenging with increased risks of repeat surgical intervention, and percutaneous techniques including transcatheter aortic valve replacement are assuming greater importance. In this manuscript, we provide a comprehensive approach to contemporary diagnosis and management of aortic valve disorders in the setting of LVAD therapy.

Surgical Interventions for Late Aortic Valve Regurgitation Associated with Continuous Flow-Left Ventricular Assist Device Therapy: Experience Gained and Lessons Learned

This study aimed to investigate the outcomes of surgical interventions for symptomatic moderate-to-severe aortic regurgitation (AR), including aortic valve replacement (AVR) and repair (AVP), in 184 patients who underwent continuous flow-left ventricular assist device (Cf-LVAD) implantation as a bridge-to-transplant (BTT) between November 2007 and April 2020. Ten patients (median age, 34 (25-41) years; 60% men) underwent surgical interventions (AVR, n = 6; AVP, n = 4) late after cf-LVAD implantation. The median duration after the device implantation was 34 (24-44) months. Three patients required additional tricuspid valve repair. Aortic valve suturing resulted in severe recurrent AR 6 months postoperatively, due to leaflet cutting in one patient. Seven patients with AVR survived without regurgitation during the study period, except for one non-survivor complicated by liver failure due to postoperative right heart failure. Therefore, six patients after AVP (n = 4) and AVR (n = 2) underwent successful heart transplantation 7 (4-13) months after aortic intervention. Kaplan-Meier analysis showed no significant difference in overall survival through 5 years after cf-LVAD implantation, regardless of the surgical AV intervention chosen (log-rank test, p = 0.86). In conclusion, surgical interventions (AVR or AVP) for patients with an ongoing cf-LVAD are safe, effective, and viable options.

Key questions about aortic insufficiency in patients with durable left ventricular assist devices

The development of the latest generation of durable left ventricular assist devices (LVAD) drastically decreased adverse events such as pump thrombosis or disabling strokes. However, time-related complications such as aortic insufficiency (AI) continue to impair outcomes following durable LVAD implantation, especially in the context of long-term therapy. Up to one-quarter of patients with durable LVAD develop moderate or severe AI at 1 year and its incidence increases with the duration of support. The continuous regurgitant flow within the left ventricle can compromise left ventricular unloading, increase filling pressures, decrease forward flow and can thus lead to organ hypoperfusion and heart failure. This review aims to give an overview of the epidemiology, pathophysiology, and clinical consequences of AI in patients with durable LVAD.

Concomitant or late aortic valve intervention and its efficacy for aortic insufficiency associated with continuous-flow left ventricular assist device implantation

Moderate to severe aortic insufficiency (AI) in patients who underwent continuous-flow left ventricular assist device (CF-LVAD) implantation is a significant complication. According to the INTERMACS registry analysis, at least mild AI occurs in 55% of patients at 6 months after CF-LVAD implantation and moderate to severe AI is significantly associated with higher rates of re-hospitalization and mortality. The clinical implications of these data may underscore consideration of prophylactic aortic valve replacement, or repair, at the time of CF-LVAD implantation, particularly with expected longer duration of support and in patients with preexisting AI that is more than mild. More crucially, even if a native aortic valve is seemingly competent at the time of VAD implantation, we frequently find de novo AI as time goes by, potentially due to commissural fusion in the setting of inconsistent aortic valve opening or persistent valve closure caused by CF-LVAD support, that alters morphological and functional properties of innately competent aortic valves. Therefore, close monitoring of AI is mandatory, as the prognostic nature of its longitudinal progression is still unclear. Clearly, significant AI during VAD support warrants surgical intervention at the appropriate timing, especially in patients of destination therapy. Nonetheless, such an uncertainty in the progression of AI translates to a lack of consensus regarding the management of this untoward complication. In practice, proposed surgical options are aortic valve replacement, repair, closure, and more recently transcatheter aortic valve implantation or closure. Transcatheter approach is of course less invasive, however, its efficacy in terms of long-term outcome is limited. In this review, we summarize the recent evidence related to the pathophysiology and surgical treatment of AI associated with CF-LVAD implantation.

Update on the Practical Role of Echocardiography in Selection, Implantation, and Management of Patients Requiring Left Ventricular Assist Device Therapy

PURPOSE OF REVIEW

Echocardiography is a valuable tool for management of patients with a left ventricular assist device (LVAD). We present an updated review on the practical applications of the role of echocardiography for pre- and postoperative evaluation of patients selected.

RECENT FINDINGS

The LVAD is a temporary or permanent option for patients with advanced heart failure who are unresponsive to other therapy. Use of the device has its own risks, and implantation remains a complex procedure. Transthoracic and transesophageal echocardiography are useful tools for patient evaluation and monitoring both peri- and postoperatively, as we previously presented. Assessment of left and right ventricular function, complications such as thrombus formation or intracardiac shunting, and valvular disease are all important in this assessment. This also aids in predicting postoperative complications. Placement of the device is confirmed intraoperatively, and subsequent ramp studies are used to determine optimal device settings. Right ventricular (RV) failure is the most common postoperative complication and preoperative evaluation of its function is crucial. Studies suggest that tricuspid annular plane systolic excursion, RV fractional area change, and RV global longitudinal strain are strong predictors of RV failure; LV ejection fraction, size, and end-diastolic diameter are also important markers. Aortic regurgitation and mitral stenosis must always be corrected prior to LVAD placement. However, direct visualization before and after implantation, especially to rule out potential contraindications such as thrombi, cannot be overemphasized. Ramp studies remain an integral part of device optimization and may result in greater myocardial recovery than previously realized.

A multidisciplinary approach for the emergency care of patients with left ventricular assist devices: A practical guide

The use of a left ventricular assist device (LVAD) as a bridge-to-transplantation or destination therapy to support cardiac function in patients with end-stage heart failure (HF) is increasing in all developed countries. However, the expertise needed to implant and manage patients referred for LVAD treatment is limited to a few reference centers, which are often located far from the patient's home. Although patients undergoing LVAD implantation should be permanently referred to the LVAD center for the management and follow-up of the device also after implantation, they would refer to the local healthcare service for routine assistance and urgent health issues related to the device or generic devices. Therefore, every clinician, from a bigger to a smaller center, should be prepared to manage LVAD carriers and the possible risks associated with LVAD management. Particularly, emergency treatment of patients with LVAD differs slightly from conventional emergency protocols and requires specific knowledge and a multidisciplinary approach to avoid ineffective treatment or dangerous consequences. This review aims to provide a standard protocol for managing emergency and urgency in patients with LVAD, elucidating the role of each healthcare professional and emphasizing the importance of collaboration between the emergency department, in-hospital ward, and LVAD reference center, as well as algorithms designed to ensure timely, adequate, and effective treatment to patients with LVAD.

Clinical Outcomes of Transcatheter Aortic Valve Replacement (TAVR) vs. Surgical Aortic Valve Replacement (SAVR) in Patients With Durable Left Ventricular Assist Device (LVAD)

BACKGROUND

Patients with left ventricular assist device often develop aortic insufficiency requiring an intervention on the aortic valve. We sought to analyze the outcomes of patients with a history of LVAD who underwent either transcatheter aortic valve replacement or surgical aortic valve replacement.

METHODS

The Nationwide Readmission Database was used to extract relevant patient information from January 1, 2016, to December 31, 2018. The NRD is a nationally representative sample of all-payer discharges from U.S. non-federal hospitals. The primary outcome of interest was in-hospital mortality. Secondary outcomes included length of stay, clinical outcomes, costs, and 30-day all-cause readmissions. Complex samples multivariable logistic and linear regression models were used to determine the association of procedure type with outcomes.

RESULTS

Among 148 hospitalizations with a history of LVAD, 87 underwent TAVR, and 61 underwent SAVR. The inpatient mortality in SAVR group was numerically higher compared to the TAVR cohort, however, it did not reach statistical significance. The use of invasive mechanical ventilation, and rates of cardiogenic shock, bleeding, and vascular complications were higher in the SAVR cohort compared to the TAVR cohort. The mean length of stay and costs were higher in the SAVR cohort compared to the TAVR cohort. The 30-day all-cause readmission rate was numerically higher in the SAVR group but not statistically significant.

CONCLUSIONS

TAVR in patients with LVAD may be a viable treatment option for patients with AI with potential for better inpatient mortality and inpatient outcomes compared to patients who undergo SAVR in appropriately selected patients.

Impact of progressive aortic regurgitation on outcomes after left ventricular assist device implantation

Aortic regurgitation (AR) following continuous flow left ventricular assist device implantation (cf-LVAD) may adversely impact outcomes. We aimed to assess the incidence and impact of progressive AR after cf-LVAD on prognosis, biomarkers, functional capacity and echocardiographic findings. In an analysis of the PCHF-VAD database encompassing 12 European heart failure centers, patients were dichotomized according to the progression of AR following LVAD implantation. Patients with de-novo AR or AR progression (AR_1) were compared to patients without worsening AR (AR_0). Among 396 patients (mean age 53 ± 12 years, 82% male), 153 (39%) experienced progression of AR over a median of 1.4 years on LVAD support. Before LVAD implantation, AR_1 patients were less frequently diabetic, had lower body mass indices and higher baseline NT-proBNP values. Progressive AR did not adversely impact mortality (26% in both groups, HR 0.91 [95% CI 0.61-1.36]; P = 0.65). No intergroup variability was observed in NT-proBNP values and 6-minute walk test results at index hospitalization discharge and at 6-month follow-up. However, AR_1 patients were more likely to remain in NYHA class III and had worse right ventricular function at 6-month follow-up. Lack of aortic valve opening was related to de-novo or worsening AR (P < 0.001), irrespective of systolic blood pressure (P = 0.67). Patients commonly experience de-novo or worsening AR when exposed to continuous flow of contemporary LVADs. While reducing effective forward flow, worsening AR did not influence survival. However, less complete functional recovery and worse RV performance among AR_1 patients were observed. Lack of aortic valve opening was associated with progressive AR.

Advancements in left ventricular assist devices to prevent pump thrombosis and blood coagulopathy

Mechanical circulatory support (MCS) devices, such as left ventricular assist devices (LVADs) are very useful in improving outcomes in patients with advanced-stage heart failure. Despite recent advances in LVAD development, pump thrombosis is one of the most severe adverse events caused by LVADs. The contact of blood with artificial materials of LVAD pumps and cannulas triggers the coagulation cascade. Heat spots, for example, produced by mechanical bearings are often subjected to thrombus build-up when low-flow situations impair washout and thus the necessary cooling does not happen. The formation of thrombus in an LVAD may compromise its function, causing a drop in flow and pumping power leading to failure of the LVAD, if left unattended. If a clot becomes dislodged and circulates in the bloodstream, it may disturb the flow or occlude the blood vessels in vital organs and cause internal damage that could be fatal, for example, ischemic stroke. That is why patients with LVADs are on anti-coagulant medication. However, the anti-coagulants can cause a set of issues for the patient-an example of gastrointestinal (GI) bleeding is given in illustration. On account of this, these devices are only used as a last resort in clinical practice. It is, therefore, necessary to develop devices with better mechanics of blood flow, performance and hemocompatibility. This paper discusses the development of LVADs through landmark clinical trials in detail and describes the evolution of device design to reduce the risk of pump thrombosis and achieve better hemocompatibility. Whilst driveline infection, right heart failure and arrhythmias have been recognised as LVAD-related complications, this paper focuses on complications related to pump thrombosis, especially blood coagulopathy in detail and potential strategies to mitigate this complication. Furthermore, it also discusses the LVAD implantation techniques and their anatomical challenges.

A Multi-Domain Simulation Study of a Pulsatile-Flow Pump Device for Heart Failure With Preserved Ejection Fraction

Mechanical circulatory support (MCS) devices are currently under development to improve the physiology and hemodynamics of patients with heart failure with preserved ejection fraction (HFpEF). Most of these devices, however, are designed to provide continuous-flow support. While it has been shown that pulsatile support may overcome some of the complications hindering the clinical translation of these devices for other heart failure phenotypes, the effects that it may have on the HFpEF physiology are still unknown. Here, we present a multi-domain simulation study of a pulsatile pump device with left atrial cannulation for HFpEF that aims to alleviate left atrial pressure, commonly elevated in HFpEF. We leverage lumped-parameter modeling to optimize the design of the pulsatile pump, computational fluid dynamic simulations to characterize hydraulic and hemolytic performance, and finite element modeling on the Living Heart Model to evaluate effects on arterial, left atrial, and left ventricular hemodynamics and biomechanics. The findings reported in this study suggest that pulsatile-flow support can successfully reduce pressures and associated wall stresses in the left heart, while yielding more physiologic arterial hemodynamics compared to continuous-flow support. This work therefore supports further development and evaluation of pulsatile support MCS devices for HFpEF.

Invasive Haemodynamic Assessment Before and After Left Ventricular Assist Device Implantation: A Guide to Current Practice

Mechanical circulatory support for the management of advanced heart failure is a rapidly evolving field. The number of durable long-term left ventricular assist device (LVAD) implantations increases each year, either as a bridge to heart transplantation or as a stand-alone ‘destination therapy’ to improve quantity and quality of life for people with end-stage heart failure. Advances in cardiac imaging and non-invasive assessment of cardiac function have resulted in a diminished role for right heart catheterisation (RHC) in general cardiology practice; however, it remains an essential tool in the evaluation of potential LVAD recipients, and in their long-term management. In this review, the authors discuss practical aspects of performing RHC and potential complications. They describe the haemodynamic markers associated with a poor prognosis in patients with left ventricular systolic dysfunction and evaluate the measures of right ventricular (RV) function that predict risk of RV failure following LVAD implantation. They also discuss the value of RHC in the perioperative period; when monitoring for longer term complications; and in the assessment of potential left ventricular recovery.

Aortic Insufficiency Causes Symptomatic Heart Failure during Left Ventricular Assist Device Support

De novo aortic insufficiency is often documented during long-term left ventricular assist device (LVAD) support, despite the absence of aortic insufficiency at the time of LVAD implantation. However, whether aortic insufficiency affects long-term mortality and symptomatic heart failure in LVAD-supported patients remains controversial. We aimed to examine whether aortic insufficiency development influenced mortality and symptomatic heart failure following LVAD implantation. Fifty-three patients who underwent durable LVAD implantation between January 1, 2008 and April 31, 2017 were retrospectively examined in a single center institute. After discharge, we performed the echocardiographic examination in accordance with the Japanese registry for the mechanically assisted circulatory support protocol. Aortic insufficiency was graded on an interval scale (severe = 4, moderate = 3, mild = 2, trivial or none = 1). Kaplan-Meier estimates for long-term mortality at the follow-up were generated. We used a logistic regression model to identify risk factors for symptomatic heart failure. The overall median duration of LVAD support was 856.3 ± 430.8 days (range, 12-1,744 days). We did not observe a significant difference in long-term mortality in patients with aortic insufficiency ≥ 3 grade compared with patients with aortic insufficiency < 3 grade (P = 0.767; log-rank). Aortic insufficiency was associated with an increased risk for heart failure event after discharge (odds ratio, 4.12; confidence interval, 1.48-16.93; P = 0.005). Aortic insufficiency was an independent risk factor for symptomatic heart failure and was not associated with long-term mortality. Aortic insufficiency progression was associated with symptomatic heart failure.

Long-Term renal function after implantation of continuous-flow left ventricular assist devices: A single center study

Background

Implantable continuous-flow left ventricular assist device (LVAD) improve renal function in advanced heart failure. However, the long-term effects of LVAD on renal function have not been investigated thoroughly. We aimed to assess long-term renal function in patients with LVAD support and to identify predictors for late deterioration in renal function (LDRF).

Methods

One hundred patients underwent LVAD implantation as a bridge to transplant at the University of Tokyo Hospital between May 2011 and December 2018. We assessed renal function at intervals (preoperative, 1, 6, 12, 18, 24 and 30 months after LVAD implantation). We divided patients into two groups: “with LDRF,” whose renal function at 30 months had decreased by >25% compared with preoperatively (n = 14), and “without LDRF” (n = 55).

Results

Renal function improved at 1 month, returned to preoperative levels at 6 months, and remained there up to 30 months after LVAD implantation. However, renal function impairment became evident in patients with LDRF 18 months after LVAD implantation. A ratio of right atrial pressure/pulmonary artery wedge pressure > 0.57 and left ventricular dimension diastole ≤ 67 mm were preoperative independent risk factors for LDRF. In addition, the incidence of perioperative acute kidney injury, ventricular arrhythmia, aortic insufficiency, and late right ventricular failure was significantly higher in patients with LDRF.

Conclusion

LDRF after LVAD implantation corresponded to several risk factors, including a small left ventricle and LVAD-related complications, such as right ventricular failure.

Left Ventricular Assist Device Support-Induced Alteration of Mechanical Stress on Aortic Valve and Aortic Wall

The aim of this study was to evaluate the fluid dynamics in the aortic valve and proximal aorta during continuous-flow left ventricular assist device (LVAD) support using epiaortic echocardiography and vector flow mapping technology. A total of 12 patients who underwent HeartMate 3 implantation between December 2018 and February 2020 were prospectively examined. The wall shear stress (WSS) on the ascending aorta, aortic root, and aortic valve was evaluated before and after LVAD implantation. The median age of the cohort was 62 years and 17% were women. The peak WSS on the ascending aorta (Pre 1.48 [0.86-1.69] [Pascal {Pa}] vs. Post 0.33 [0.21-0.58] [Pa]; p = 0.002), aortic root (Pre 0.46 [0.31-0.58] (Pa) vs. Post 0.18 [0.12-0.25] (Pa); p = 0.001), and ventricularis of the aortic valve (Pre 1.76 [1.59-2.30] (Pa) vs. Post 0.30 [0.10-0.61] (Pa); p = 0.001) was significantly lower after LVAD implantation. No difference in WSS was observed on the fibrosa of the aortic valve (Pre 0.36 [0.22-0.53] (Pa) vs. Post 0.38 [0.38-0.52] (Pa); p = 0.850) before and after implantation. The WSS on the ascending aorta, aortic root, and ventricularis of the aortic valve leaflets was significantly altered by LVAD implantation, providing preliminary data on the potential contribution of fluid dynamics to LVAD-induced aortic insufficiency and root thrombus.

Secondary aortic valve replacement in continuous flow left ventricular assist device therapy

The purpose of the study was to investigate the outcome of secondary surgical aortic valve replacement (sSAVR) in patients with severe aortic regurgitation (AR) in the context of ventricular assist device (VAD) therapy. From 2009 to 2020, 792 patients underwent cf-LVAD implantation [HVAD (Medtronic, USA), n = 585, and HM 3 (Abbott, USA), n = 207]. All cf-LVAD patients with severe AR requiring secondary AVR were enrolled in this study. A total of six patients (median, 40 years, IQR; 34-61 years, 50% male) underwent secondary surgical aortic valve replacement (sSAVR) after cf-LVAD implantation. Median time of previous LVAD support was 26 months (IQR: 21-29 months). Two patients required additional tricuspid valve repair (TVR) and one patient underwent SAVR after failed TAVR. Four patients needed temporary right ventricular assist device (RVAD) with a median of 30 days (IQR; 29-33 days). Three patients were bridged to urgent heart transplantation due to persevering right heart failure, whereas two destination therapy (DT) candidates survived without any associated complications. An additional DT patient died of pneumonia 1 month after sSAVR. Secondary surgical aortic valve replacement in ongoing LVAD patients is an advanced procedure for a complex cohort. In our series, sSAVR was safely performed and effective, but involved a high-risk for subsequent right heart failure, requiring urgent heart transplantation. In LVAD patients with severe AR requiring treatment where TAVR is not feasible, sSAVR can be evaluated as salvage option for bridge to transplant patients or selected destination therapy candidates.

Ventricular assist devices implantation: surgical assessment and technical strategies

Along with the worldwide increase in continuous left ventricular assist device (LVAD) strategy adoption, more and more patients with demanding anatomical and clinical features are currently referred to heart failure (HF) departments for treatment. Thus surgeons have to deal, technically, with re-entry due to previous cardiac surgery procedures, porcelain aorta, peripheral vascular arterial disease, concomitant valvular or septal disease, biventricular failure. New surgical techniques and surgical tools have been developed to offer acceptable postoperative outcomes to all mechanical circulatory support recipients. Several less invasive and/or thoracotomic approaches for surgery combined with various LVAD inflow and outflow graft alternative anastomotic sites for system placement have been reported and described to solve complex clinical scenarios. Surgical techniques have been upgraded with further technical tips to preserve the native anatomy in case of re-entry for heart transplantation, myocardial recovery or device explant. The current continuous-flow miniaturized and intrapericardial devices provide versatility and technical advantages. However, the surgical planning requires a careful multidisciplinary evaluation which must be driven by a dedicated and well-trained Heart Failure team. Biventricular assist device (BVAD) implantation by adoption of the newer radial pumps might be a challenge. However, the results are encouraging thus remaining a valid option. This paper reviews and summarizes LVAD preoperative assessment and current surgical techniques for implantation.

Biomechanical effects of the novel series LVAD on the aortic valve

BACKGROUND AND OBJECTIVE

The series type of LVAD (i.e., BJUT-II VAD) is a novel left ventricular assist device, whose effects on the aortic valve remain unclear.

METHODS

The biomechanical effects of BJUT-II VAD on the aortic valve were investigated by using a fluid-structure interaction method. The geometric model of BJUT-II VAD was virtually implanted into the ascending aorta to generate the realistic flow pattern for the aortic valve (i.e., support). In addition, the biomechanical states of the aortic valve without BJUT-II VAD support was computed as control (i.e., control case).

RESULTS

Results demonstrated that the biomechanical effects of BJUT-II VAD were quite different from that resulting from traditional "bypass LVAD." Compared with those in the control case, BJUT-II VAD support could significantly reduce the stress load of the leaflet (maximum stress, 0.5 MPa in the control case vs. 0.12 MPa in the support case). Similarly, the rapid valve opening time (100 ms in the control case vs. 175 ms in the support case) and rapid valve closing time (50 ms in the control case vs. 150 ms in the support case) in the support case were obviously longer than those in the control case. Moreover, BJUT-II VAD support reduced retrograde blood flow during the diastolic phase and significantly changed the distribution of WSS of the leaflets.

CONCLUSIONS

In summary, while unloading the left ventricle, BJUT-II VAD could provide beneficial biomechanical states for the aortic leaflets, thereby reducing the risk of aortic valve disease.

Survival following a concomitant aortic valve procedure during left ventricular assist device surgery: an ISHLT Mechanically Assisted Circulatory Support (IMACS) Registry analysis

Aims

The aim of this study was to compare early‐ and late‐term survival and causes of death between patients with and without a concomitant aortic valve (AoV) procedure during continuous‐flow left ventricular assist device (LVAD) surgery.

Methods and results

All adult primary continuous‐flow LVAD patients on the International Society of Heart and Lung Transplantation (ISHLT) Mechanically Assisted Circulatory Support (IMACS) Registry (n = 15 267) were included in this analysis and stratified into patients submitted to a concomitant AoV procedure (AoV replacement or AoV repair) and patients without an AoV procedure. The primary outcome was early (≤90 days) survival post‐LVAD surgery. Secondary outcomes were late survival (survival during the entire follow‐up period) and conditional survival (in patients who survived the first 90 days post‐LVAD surgery), and determinants. Patients who underwent concomitant AoV replacement (n = 457) had significantly reduced late survival compared with patients with AoV repair (n = 328) or without an AoV procedure (n = 14 482) (56% vs. 61% and 62%, respectively; P = 0.001). After adjustment for other significant predictors, concomitant AoV replacement remained an independent predictor for early [hazard ratio (HR) 1.226, 95% confidence interval (CI) 1.037–1.449] and late (HR 1.477, 95% CI 1.154–1.890) mortality. However, patients undergoing AoV replacement or repair, in whom the presence of moderate‐to‐severe AoV regurgitation was diagnosed prior to LVAD implantation, had survival similar to patients not undergoing AoV interventions.

Conclusions

Concomitant AoV surgery in patients undergoing LVAD implantation is an independent predictor of mortality. Additional research is needed to determine the best AoV surgical strategy at the time of LVAD surgery.

The Aortic Valve: The Gatekeeper of the LVAD

•

Acute cardiogenic shock was encountered in a patient with an LVAD system.

•

Acute AR was due to native aortic valve/sinus of Valsalva thrombosis.

•

TEE can aid diagnosis in patients with LVAD systems and acute valvular dysfunction.

Biomechanical effects of the working modes of LVADs on the aortic valve: A primary numerical study

Aortic valve diseases caused by the support from left ventricular assist devices (LVADs) have attracted increasing attention due to the wide application of the LVADs. However, the biomechanical effects of the working modes of LVADs on the aortic valve are still poorly understood. Hence, in this study, these biomechanical effects are investigated using a novel fluid-structure interaction method, which combines the lattice Boltzmann and the finite element methods. On the basis of the clinical practice, three working modes of LVADs, namely, the constant flow, co-pulse, and counter pulse modes, are chosen. Results demonstrate that the working mode of LVADs is an important factor as it can change the biomechanical states of the aortic valve and the hemodynamic environment in the aortic root directly. Compared with the constant flow mode, the two other working modes can provide better biomechanical effects on the aortic valve. However, the advantages of the co-pulse and the counter pulse modes on the aortic valve are not the same. The LVADs in the co-pulse mode can remarkable reduce the pressure load of the leaflets during the diastolic phase (maximum stress: co-pulse mode, 0.85 MPa; constant flow mode, 1.23 MPa; counter pulse mode, 1.50 MPa). By contrast, the LVADs in the counter pulse mode can achieve the highest effective orifice area of the aortic valve (co-pulse mode: 0.12 cm², constant flow mode: 0.17 cm², counter pulse mode: 0.25 cm²). In sum, the co-pulse mode is suitable for patients with certain cardiac function, because this mode keeps the valve open intermittently and reduces the pressure load on the aortic leaflets during the diastolic phase to prevent valve remodeling. By contrast, the counter pulse mode is suitable for patients with severely impaired cardiac function, because this mode keeps the valve open as much as possible and provides high blood perfusion.

Use of patient-specific computational models for optimization of aortic insufficiency after implantation of left ventricular assist device

OBJECTIVE

Aortic incompetence (AI) is observed to be accelerated in the continuous-flow left ventricular assist device (LVAD) population and is related to increased mortality. Using computational fluid dynamics (CFD), we investigated the hemodynamic conditions related to the orientation of the LVAD outflow in these patients.

METHOD

We identified 10 patients with new aortic regurgitation, and 20 who did not, after LVAD implantation between 2009 and 2018. Three-dimensional models of patients' aortas were created from their computed tomography scans. The geometry of the LVAD outflow graft in relation to the aorta was quantified using azimuth angles (AA), polar angles (PAs), and distance from aortic root. The models were used to run CFD simulations, which calculated the pressures and wall shear stress (rWSS) exerted on the aortic root.

RESULTS

The AA and PA were found to be similar. However, for combinations of high values of AA and low values of PA, there were no patients with AI. The distance from aortic root to the outflow graft was also smaller in patients who developed AI (3.39 ± 0.7 vs 4.07 ± 0.77 cm, P = .04). There was no significant difference in aortic root pressures in the 2 groups. The rWSS was greater in AI patients (4.60 ± 5.70 vs 2.37 ± 1.20 dyne/cm², P < .001). Qualitatively, we observed a trend of greater perturbations, regions of high rWSS, and flow eddies in the AI group.

CONCLUSIONS

Using CFD simulations, we demonstrated that patients who developed de novo AI have greater rWSS at the aortic root, and their outflow grafts were placed closer to the aortic roots than those patients without de novo AI.