Reversibility of severe mitral valve regurgitation after left ventricular assist device implantation: single-centre observations from a real-life population of patients

Left ventricular assist device implantation and concomitant mitral valve surgery: A systematic review and meta-analysis

BACKGROUND

The management of concomitant valvular lesions in patients undergoing left ventricular assist device (LVAD) implantation remains a topic of debate. This systematic review and meta-analysis aimed to evaluate the existing evidence on postoperative outcomes following LVAD implantation, with and without concomitant MV surgery.

METHODS

A systematic database search was conducted as per PRISMA guidelines, of original articles comparing LVAD alone to LVAD plus concomitant MV surgery up to February 2023. The primary outcomes assessed were overall mortality and early mortality, while secondary outcomes included stroke, need for right ventricular assist device (RVAD) implantation, postoperative mitral valve regurgitation, major bleeding, and renal dysfunction.

RESULTS

The meta-analysis included 10 studies comprising 32 184 patients. It revealed that concomitant MV surgery during LVAD implantation did not significantly affect overall mortality (OR:0.83; 95% CI: 0.53 to 1.29; p = 0.40), early mortality (OR:1.17; 95% CI: 0.63 to 2.17; p = 0.63), stroke, need for RVAD implantation, postoperative mitral valve regurgitation, major bleeding, or renal dysfunction. These findings suggest that concomitant MV surgery appears not to confer additional benefits in terms of these clinical outcomes.

CONCLUSION

Based on the available evidence, concomitant MV surgery during LVAD implantation does not appear to have a significant impact on postoperative outcomes. However, decision-making regarding MV surgery should be individualized, considering patient-specific factors and characteristics. Further research with prospective studies focusing on specific patient populations and newer LVAD devices is warranted to provide more robust evidence and guide clinical practice in the management of valvular lesions in LVAD recipients.

Pathophysiology and management of valvular disease in patients with destination left ventricular assist devices

Over the last two decades, implantable continuous flow left ventricular assist devices (LVAD) have proven to be invaluable tools for the management of selected advanced heart failure patients, improving patient longevity and quality of life. The presence of concomitant valvular pathology, including that involving the tricuspid, mitral, and aortic valve, has important implications relating to the decision to move forward with LVAD implantation. Furthermore, the presence of concomitant valvular pathology often influences the surgical strategy for LVAD implantation. Concomitant valve repair or replacement is not uncommonly required in such circumstances, which increases surgical complexity and has demonstrated prognostic implications both short and longer term following LVAD implantation. Beyond the index operation, it is also well established that certain valvular pathologies may develop or worsen over time following LVAD support. The presence of pre-existing valvular pathology or that which develops following LVAD implant is of particular importance to the destination therapy LVAD patient population. As these patients are not expected to have the opportunity for heart transplantation in the future, optimization of LVAD support including ameliorating valvular disease is critical for the maximization of patient longevity and quality of life. As collective experience has grown over time, the ability of clinicians to effectively address concomitant valvular pathology in LVAD patients has improved in the pre-implant, implant, and post-implant phase, through both medical management and procedural optimization. Nevertheless, there remains uncertainty over many facets of concomitant valvular pathology in advanced heart failure patients, and the understanding of how to best approach these conditions in the LVAD patient population continues to evolve. Herein, we present a comprehensive review of the current state of the field relating to the pathophysiology and management of valvular disease in destination LVAD patients.

Role of the mitral valve in left ventricular assist device pathophysiology

Functional mitral regurgitation (MR) in the setting of heart failure results from progressive dilatation of the left ventricle (LV) and mitral annulus. This leads to leaflet tethering with posterior displacement. Contrary to common assumptions, MR often does not resolve with LVAD decompression of the LV alone. The negative impact of significant (moderate-severe) mitral regurgitation in the LVAD setting is becoming better recognized in terms of its harmful effect on right heart function, pulmonary vascular resistance and hospital readmissions. However, controversies remain regarding the threshold for intervention and management. At present, there are no consensus indications for the repair of significant mitral regurgitation at the time of LVAD implantation due to the conflicting data regarding potential adverse effects of MR on clinical outcomes. In this review, we summarize the current understanding of MR pathophysiology in patients supported with LVAD and potential future management strategies.

Right heart failure after left ventricular assist device: From mechanisms to treatments

Left ventricular assist device (LVAD) therapy is a lifesaving option for patients with medical therapy-refractory advanced heart failure. Depending on the definition, 5-44% of people supported with an LVAD develop right heart failure (RHF), which is associated with worse outcomes. The mechanisms related to RHF include patient, surgical, and hemodynamic factors. Despite significant progress in understanding the roles of these factors and improvements in surgical techniques and LVAD technology, this complication is still a substantial cause of morbidity and mortality among LVAD patients. Additionally, specific medical therapies for this complication still are lacking, leaving cardiac transplantation or supportive management as the only options for LVAD patients who develop RHF. While significant effort has been made to create algorithms aimed at stratifying risk for RHF in patients undergoing LVAD implantation, the predictive value of these algorithms has been limited, especially when attempts at external validation have been undertaken. Perhaps one of the reasons for poor performance in external validation is related to differing definitions of RHF in external cohorts. Additionally, most research in this field has focused on RHF occurring in the early phase (i.e., ≤1 month) post LVAD implantation. However, there is emerging recognition of late-onset RHF (i.e., > 1 month post-surgery) as a significant cause of morbidity and mortality. Late-onset RHF, which likely has a unique physiology and pathogenic mechanisms, remains poorly characterized. In this review of the literature, we will describe the unique right ventricular physiology and changes elicited by LVADs that might cause both early- and late-onset RHF. Finally, we will analyze the currently available treatments for RHF, including mechanical circulatory support options and medical therapies.

Impact of severe mitral regurgitation on postoperative outcome after durable left-ventricular assist device implantation

BACKGROUND

Mitral valve regurgitation (MR) is a common finding in patients with end-stage heart failure. The aim of the study was to analyze the impact of preoperative moderate-to-severe MR on postoperative outcomes and survival after durable left-ventricular assist device (LVAD) implantation.

METHODS

From August 2010 to May 2021, 246 patients underwent a durable LVAD implantation. We stratified the patients into two groups: Group A (n = 109) presented with MR 0-I°, and Group B presented with MR II-III° (n = 137). MR II-III° was defined according to the current recommendations (i.e., vena contracta ≥ 7 mm, regurgitation volume ≥ 30 ml or effective regurgitation orifice area ≥ 20 mm² ).

RESULTS

Significantly more patients in Group B suffered from pulmonary hypertension and presented with chronic obstructive lung disease. We observed significantly higher rates of tricuspid regurgitation (TR) II-III° in Group B (76.1%) versus Group A (14.8%) (p < 0.001) and TR III° in Group B (30.4%) versus Group A (3.7%) (p < 0.001). There was no difference in the incidence of right heart failure between the groups. Within our cohort, the in-hospital, 1-year, 3-year, and 5-year mortality was 22.4%, 32.1%, 50.7%, and 64.4%, respectively. Group B showed significantly worse overall survival (p = 0.05). Patients with preoperative TR II-III° had a significantly worse survival than those with TR 0-I° (p = 0.048). In patients presenting with MR II-III°, we discovered that TR III° seems to predict both in-hospital and mid-term mortality.

CONCLUSION

MR II-III° negatively affects the outcomes in patients requiring LVAD implantation. Persisting MR II-III° is an independent predictor of mortality. Patients with concomitant preoperative TR II-III° are at increased risk of developing postoperative major adverse events. Addressing the MR might be considered for these patients.

Validation of mitral regurgitation reversibility in patients with HeartMate 3 implantation

The resolution of functional mitral valve regurgitation (MR) in patients awaiting left ventricular assist device (LVAD) implantation is discussed controversially. The present study analyzed MR and echocardiographic parameters of the third-generation LVAD HeartMate 3 (HM3) over 3 years. Of 135 LVAD patients (with severe MR, n = 33; with none, mild, or moderate MR, n = 102), data of transthoracic echocardiography were included preoperatively to LVAD implantation, up to 1 month postoperatively, and at 1, 2, and 3 years after LVAD implantation. Demographic data and clinical characteristics were collected. Severe MR was reduced immediately after LVAD implantation in all patients. The echocardiographic parameters left ventricular end-diastolic diameter (P < .001), right ventricular end-diastolic diameter (P < .001), tricuspid annular plane systolic excursion (P < .001), and estimated pulmonary artery pressure (P < .001) decreased after HM3 implantation independently from the grade of MR prior to implantation and remained low during the 2 years follow-up period. Following LVAD implantation, right heart failure, ventricular arrhythmias, ischemic stroke as well as pump thrombosis and bleeding events were comparable between the groups. The incidences of death and cardiac death did not differ between the patient groups. Furthermore, the Kaplan-Meier analysis showed that survival was comparable between the groups (P = .073). HM3 implantation decreases preoperative severe MR immediately after LVAD implantation. This effect is long-lasting in most patients and reinforces the LVAD implantation without MR surgery. The complication rates and survival were comparable between patients with and without severe MR.

Persistent mitral regurgitation after left ventricular assist device: a clinical conundrum

Aims

Persistent mitral valve regurgitation (MR) after continuous flow left ventricular assist device implantation (cfLVAD) is associated with pulmonary hypertension and right ventricular failure with variable effects on survival across published studies. The aim of this study is to determine the incidence and predictors of persistent MR at 6‐month follow‐up after cfLVAD implantation and its impact on survival, haemodynamics, right ventricular function, and morbidity.

Methods and results

We performed a retrospective review of all adult cfLVAD recipients from January 2012 to June 2017 at a single tertiary university hospital with follow‐up until April 2019. Primary outcome was to compare survival between patients with no‐to‐mild compared with persistent moderate‐to‐severe MR at 6 months. Secondary outcomes included right heart failure (RHF), length of stay, re‐hospitalizations, and composite of death, transplant, and pump exchange during the length of follow‐up. Final analytic sample was 111 patients. The incidence of persistent moderate or severe MR at 6 months was 26%. Significant predictors of persistent MR at 6 months were left atrium dimension and volume. The group with persistent moderate‐to‐severe MR at 6 months had higher incidence of RHF at 6 months (45% vs. 25%, P = 0.04). There was no difference in survival at 1 year between the groups (no‐to‐mild MR 85.5%, moderate‐to‐severe MR 87.9%, Wilcoxon P‐value = 0.63). There was no difference in re‐hospitalizations, length of stay, composite of death, transplant, or pump exchange during the length of follow‐up between the comparison groups.

Conclusions

Persistent moderate‐to‐severe MR after cfLVAD implantation is present in one fourth of patients and is associated with increased incidence of RHF, higher mean pulmonary pressure, and pulmonary capillary wedge pressure with no effect on 1 year survival. Increased left atrium size was associated with persistent moderate‐to‐severe MR at 6 months.

Impact of Pre-Existing Mitral Regurgitation Following Left Ventricular Assist Device Implant

OBJECTIVES

Optimal management of significant mitral regurgitation (SMR) during left ventricular assist device (LVAD) placement remains uncertain. This study evaluates the effect of untreated preop SMR on outcomes following LVAD implant.

METHODS

Adults undergoing primary LVAD placement from April 2004 to May 2017 were included. Most recent preop transthoracic echocardiogram (TTE) was used to divide patients into an SMR group with moderate or greater regurgitation, and a group without SMR. Patients underwent LVAD implant without correction of SMR. Primary endpoint was 3-year postoperative survival, with secondary endpoints of length of stay (LOS), resolution of SMR following LVAD on postdischarge (30 day) TTE, and 1-year TTE.

RESULTS

LVAD placement was performed in 270 patients, 172 (63.7%) without SMR and 98 (36.3%) with SMR. There were no differences in comorbidities including diabetes, hypertension, and renal disease. Preop ejection fraction was similar, but a higher pulmonary vascular resistance was recorded in the SMR group (3.6 vs 3.0 Wood Units, P = 0.048). There was no difference in 3-year mortality between the 2 cohorts (log-rank P = 0.0.803). The SMR group had decreased LOS (median 19.5 vs 22 days, P = 0.009). Of the 98 SMR patients, 91 (92.9%) had resolution of SMR to less than moderate at 30 days. At 1 year, 15% of those with preoperative SMR had recurrent SMR.

CONCLUSIONS

Patients undergoing LVAD placement with preop SMR experience no differences in mortality, and a majority experience resolution of MR after implant. Longer-term SMR recurrence and need for mitral intervention with LVAD implant warrant further investigation.

Consequences of functional mitral regurgitation and atrial fibrillation in patients with left ventricular assist devices

BACKGROUND

Functional mitral regurgitation (MR) (FMR) and atrial fibrillation (AF) are common in patients undergoing left ventricular assist device (LVAD) implantation. However, the impact of FMR and AF on clinical outcomes is uncertain. This study aimed to investigate the characteristics and prognostic significance of FMR and AF in patients with LVADs.

METHODS

We retrospectively reviewed all patients who underwent LVAD implantation at our center between January 2010 and December 2017. We defined significant FMR as the ratio of MR color jet area to left atrial area of >20% and persistent or permanent AF (PeAF) as persistent or permanent AF at LVAD implantation.

RESULTS

A total of 380 patients were included in this analysis. Patients were divided into 6 groups: patients with no PeAF and no significant FMR (Group 1), patients with no PeAF but with significant FMR (Group 2), patients with PeAF but no significant FMR (Group 3), patients with PeAF and significant FMR (Group 4), patients with concomitant mitral valve surgery (MVS) at LVAD implantation and without PeAF (Group 5), and patients with concomitant MVS and with PeAF (Group 6). A total of 56 patients (15%) died within 2 years. Kaplan-Meier curve analysis demonstrated a 2-year survival of 81% in Group 1, 89% in Group 2, 87% in Group 3, 47% in Group 4, 87% in Group 5, and 79 % in Group 6 (log-rank test, p < 0.001). The multivariable Cox proportional-hazards model showed that classification in Group 4 was an independent predictor of mortality (hazard ratio, 4.31; 95% CI: 2.19-8.46; p < 0.001).

CONCLUSIONS

The coexistence of significant FMR and PeAF may represent a poor prognostic marker in patients undergoing LVAD implantation.

Impact of left ventricular assist device implantation on mitral regurgitation: An analysis from the MOMENTUM 3 trial

BACKGROUND

Mitral regurgitation (MR) determines pathophysiology and outcome in advanced heart failure. The impact of left ventricular assist device (LVAD) placement on clinically significant MR and its contribution to long-term outcomes has been sparsely evaluated.

METHODS

We evaluated the effect of clinically significant MR on patients implanted in the MOMENTUM 3 trial with either the HeartMate II (HMII) or the HeartMate 3 (HM3) at 2 years. Clinical significance was defined as moderate or severe grade MR determined by site-based echocardiograms.

RESULTS

Of 927 patients with LVAD implants without a prior or concomitant mitral valve procedure, 403 (43.5%) had clinically significant MR at baseline. At 1-month of support, residual MR was present in 6.2% of patients with HM3 and 14.3% of patients with HMII (relative risk = 0.43; 95% CI, 0.22-0.84; p = 0.01) with a low rate of worsening at 2 years. Residual MR at 1-month post-implant did not impact 2-year mortality for either the HM3 (hazard ratio [HR],1.41; 95% CI, 0.52-3.89; p = 0.50) or HMII (HR, 0.91; 95% CI, 0.37-2.26; p = 0.84) LVAD. The presence or absence of baseline MR did not influence mortality (HM3 HR, 0.86; 95% CI, 0.56-1.33; p = 0.50; HMII HR, 0.81; 95% CI, 0.54-1.22; p = 0.32), major adverse events or functional capacity. In multivariate analysis, severe baseline MR (p = 0.001), larger left ventricular dimension (p = 0.002), and implantation with the HMII instead of the HM3 LVAD (p = 0.05) were independently associated with an increased likelihood of persistent MR post-implant.

CONCLUSIONS

Hemodynamic unloading after LVAD implantation improves clinically significant MR early, sustainably, and to a greater extent with the HM3 LVAD. Neither baseline nor residual MR influence outcomes after LVAD implantation.

Ventricular arrhythmias in patients with biventricular assist devices

PURPOSE

Ventricular arrhythmias (VAs) are common in patients after left ventricular assist device (LVAD) implant and are associated with worse outcomes. However, the prevalence and impact of VA in patients with durable biventricular assist device (BIVAD) is unknown. We performed a retrospective cohort study of patients with BIVADs to evaluate the prevalence of VA and their clinical outcomes.

METHODS

Consecutive patients who received a BIVAD between June 2014 and July 2017 at our medical center were included. The prevalence of VA, defined as sustained ventricular tachycardia or fibrillation requiring defibrillation or ICD therapy, was compared between BIVAD patients and a propensity-matched population of patients with LVAD from our center. The occurrence of adverse clinical events was compared between BIVAD patients with and without VA.

RESULTS

Of the 13 patients with BIVADs, 6 patients (46%) experienced clinically significant VA, similar to a propensity-matched LVAD population (38%, p = 1.00). There were no differences in baseline characteristics between the two cohorts, except patients in the non-VA group who had worse hemodynamics (mitral regurgitation and right-sided indices), had less history of VA, and were younger. BIVAD patients with VA had a higher incidence of major bleeding (MR 3.05 (1.07-8.66), p = 0.036) and worse composite outcomes (log-rank test, p = 0.046). The presence of VA was associated with worse outcomes in both LVAD and BIVAD groups.

CONCLUSIONS

Ventricular arrhythmias are common in patients with BIVADs and are associated with worse outcomes. Future work should assess whether therapies such as ablation improve the outcome of BIVAD patients with VA.

Continuous-Flow Left Ventricular Assist Devices and Valvular Heart Disease: A Comprehensive Review

Mechanical circulatory support with implantable durable continuous-flow left ventricular assist devices (CF-LVADs) represents an established surgical treatment option for patients with advanced heart failure refractory to guideline-directed medical therapy. CF-LVAD therapy has been demonstrated to offer significant survival, functional, and quality-of-life benefits. However, nearly one-half of patients with advanced heart failure undergoing implantation of a CF-LVAD have important valvular heart disease (VHD) present at the time of device implantation or develop VHD during support that can lead to worsening right or left ventricular dysfunction and result in development of recurrent heart failure, more frequent adverse events, and higher mortality. In this review, we summarize the recent evidence related to the pathophysiology and treatment of VHD in the setting of CF-LAVD support and include a review of the specific valve pathologies of aortic insufficiency (AI), mitral regurgitation (MR), and tricuspid regurgitation (TR). Recent data demonstrate an increasing appreciation and understanding of how VHD may adversely affect the hemodynamic benefits of CF-LVAD support. This is particularly relevant for MR, where increasing evidence now demonstrates that persistent MR after CF-LVAD implantation can contribute to worsening right heart failure and recurrent heart failure symptoms. Standard surgical interventions and novel percutaneous approaches for treatment of VHD in the setting of CF-LVAD support, such as transcatheter aortic valve replacement or transcatheter mitral valve repair, are available, and indications to intervene for VHD in the setting of CF-LVAD support continue to evolve.

Right ventricular function and residual mitral regurgitation after left ventricular assist device implantation determines the incidence of right heart failure

BACKGROUND

The effect of significant mitral regurgitation (MR) on outcomes after continuous flow left ventricular assist device (cfLVAD) implantation remains unclear.

METHODS

We performed a retrospective review of prospectively collected data from 159 patients with preoperative severe MR who underwent cfLVAD implantation (2003-2017). Two-step cluster analysis using the log-likelihood distance for post-cfLVAD implantation parameters, which included right ventricular (RV) dysfunction, MR severity, and tricuspid regurgitation (TR) severity. Post-cfLVAD implantation echocardiographic parameters were obtained within the first month.

RESULTS

Cluster analysis resulted in 3 groups. Group 1 (n = 67) had mild or less MR with moderate-severe RV dysfunction (RVD). Group 2 (n = 43) had moderate-severe MR with moderate-severe RVD. Group 3 (n = 49) had moderate MR with mild RVD. Group 2 had the largest proportion with Interagency Registry for Mechanically Assisted Circulatory Support score of 1 (30.2%) and 2 (41.9%). They were more likely to undergo temporary mechanical circulatory support (18.6%) and tricuspid valve procedure (62.8%). Group 2 had the highest rate of stroke (30.2%; P = .02), hemolysis (39.5%; P = .01), device thrombosis (30%; P = .01), and worst survival (46.5%; P = .01). Survival at 5 years for groups 1, 2, and 3 were 56.0%, 17.6%, and 55.8%. Regression analysis of the entire population showed that greater MR severity after cfLVAD was associated with RV failure (P < .05; odds ratio, 1.6) and RV assist device use (P = .09; odds ratio, 1.6). After excluding tricuspid valve repairs, MR severity had a positive correlation with TR severity (R = 0.33; P < .01).

CONCLUSIONS

After cfLVAD implantation, moderate-severe MR and RVD predicted RV failure. Patients with preoperative moderate-severe MR and TR coupled with moderate-severe RVD might benefit the most from mitral and tricuspid valve intervention.