Impact of mitral regurgitation on clinical outcomes of patients with low-ejection fraction, low-gradient severe aortic stenosis undergoing transcatheter aortic valve implantation

Transcatheter aortic valve replacement in heart failure

Patients with severe aortic stenosis (AS) may develop heart failure (HF), the presence of which has traditionally been deemed as a final stage in AS progression with poor outcomes. The use of transcatheter aortic valve replacement (TAVR) has become the preferred therapy for most patients with AS and concomitant HF. With its instant afterload reduction, TAVR offers patients with HF significant haemodynamic benefits, with corresponding changes in left ventricular structure and improved mortality and quality of life. The prognostic covariates and optimal timing of TAVR in patients with less than severe AS remain unclear. The purpose of this review is to describe the association between TAVR and outcomes in patients with HF, particularly in the setting of left ventricular systolic dysfunction, acute HF, and right ventricular systolic dysfunction, and to highlight areas for future research.

Low-flow in aortic valve stenosis patients with reduced ejection fraction does not depend on left ventricular function

BACKGROUND

Patients with severe aortic stenosis (AS) and reduced left ventricular ejection fraction (LVEF) can be distinguished into high- (HG) and low-gradient (LG) subgroups. However, less is known about their characteristics and underlying (pathophysiological) hemodynamic mechanisms.

METHODS

98 AS patients with reduced LVEF were included. Subgroup characteristics were analyzed by a multimodal approach using clinical and histological data, next-generation sequencing (NGS) and applying echocardiography as well as cardiovascular magnetic resonance (CMR) imaging. Biopsy samples were analyzed with respect to fibrosis and mRNA expression profiles.

RESULTS

40 patients were classified as HG-AS and 58 patients as LG-AS. Severity of AS was comparable between the subgroups. Comparison of both subgroups revealed no differences in LVEF (p = 0.1), LV mass (p = 0.6) or end-diastolic LV diameter (p = 0.12). Neither histological (HG: 23.2% vs. LG: 25.6%, p = 0.73) and circulating biomarker-based assessment (HG: 2.6 ± 2.2% vs. LG: 3.2 ± 3.1%; p = 0.46) of myocardial fibrosis nor global gene expression patterns differed between subgroups. Mitral regurgitation (MR), atrial fibrillation (AF) and impaired right ventricular function (MR: HG: 8% vs. LG: 24%; p < 0.001; AF: HG: 30% vs. LG: 51.7%; p = 0.03; RVSVi: HG 36.7 vs. LG 31.1 ml/m2, p = 0.045; TAPSE: HG 20.2 vs. LG 17.3 mm, p = 0.002) were more frequent in LG-AS patients compared to HG-AS. These pathologies could explain the higher mortality of LG vs. HG-AS patients.

CONCLUSION

In patients with low-flow severe aortic stenosis, low transaortic gradient and cardiac output are not primarily due to LV dysfunction or global changes in gene expression, but may be attributed to other additional cardiac pathologies like mitral regurgitation, atrial fibrillation or right ventricular dysfunction. These factors should also be considered during planning of aortic valve replacement.

Prognostic Impact of Mitral Regurgitation Before and After Transcatheter Aortic Valve Replacement in Patients With Severe Low-Flow, Low-Gradient Aortic Stenosis

Background There is little evidence about the prognostic role of mitral regurgitation (MR) in patients with low-flow, low-gradient aortic stenosis undergoing transcatheter aortic valve replacement (TAVR). The aim of this study was to assess the prevalence and outcome implications of MR severity in patients with low-flow, low-gradient aortic stenosis undergoing TAVR, and to evaluate whether MR improvement after TAVR could influence clinical outcome. Methods and Results This study included consecutive patients with low-flow, low-gradient aortic stenosis undergoing TAVR at 2 Italian high-volume centers. The study population was categorized according to the baseline MR severity and to the presence of MR improvement at discharge. The primary outcome was the composite of all-cause death and hospitalization for worsening heart failure up to 1 year. The study included 268 patients; 57 (21%) patients showed MR >2+. Patients with MR >2+ showed a lower 1-year survival free from the primary outcome (P<0.001), all-cause death (P<0.001), and heart failure hospitalization (P<0.001) compared with patients with MR ≤2+. At multivariable analysis, baseline MR >2+ was an independent predictor of the primary outcome (P<0.001). Among patients with baseline MR >2+, MR improvement was reported in 24 (44%) cases after TAVR. The persistence of MR was associated with a significantly reduced survival free from the primary outcome, all-cause death, and heart failure hospitalization up to 1 year. Conclusions In this study, the presence of moderately severe to severe MR in patients with low-flow, low-gradient aortic stenosis undergoing TAVR portends a worse clinical outcome at 1 year. TAVR may improve MR severity in nearly half of the patients, resulting in a potential outcome benefit after discharge.

Challenging Decision-Making Between Transcatheter Aortic Valve Implantation and Aortic Valve Surgery: A Case of a Jehovah's Witness Patient With Severe Symptomatic Aortic Stenosis Coexisting With Severe Mitral Regurgitation and Bicuspid Aortic Valve

A 73-year-old Jehovah's witness man with a bicuspid aortic valve and a history of epilepsy presented to the emergency room with chest pain and dyspnea. Echocardiography revealed normal left ventricular systolic function, but also revealed severe aortic stenosis and severe mitral regurgitation. Coronary angiography and computerized tomography angiography ruled out any significant coronary artery disease and aortic dissection, respectively. In view of his religious views, transcatheter aortic valve implantation was considered more suitable than aortic valve surgery and was successful with a stable postoperative state. This case reaffirms that autonomy should be maintained while considering the best interest of patients in decision-making.

Concomitant mitral regurgitation in patients with low-gradient aortic stenosis: an analysis from the German Aortic Valve Registry

BACKGROUND

Patients with severe aortic stenosis (AS) frequently presented mitral regurgitation (MR), which may interfere with the standard echocardiographic measurements of mean pressure gradient (MPG), flow velocity, and aortic valve area (AVA).

AIMS

Herein we investigated the prevalence and severity of MR in patients with severe AS and its role on the accuracy of the standard echocardiographic parameters of AS quantification.

METHODS

Of all patients with severe AS undergoing transcatheter or surgical aortic valve replacement enrolled in the German Aortic Registry from 2011 to 2017, 119,641 were included in this study. The population was divided based on the values of left ventricular ejection fraction ([LVEF] > 50%, LVEF 31-50%, and LVEF ≤ 30%] and AVA (0.80 to ≤ 1.00 cm², 0.60 to < 0.80 cm², 0.40 to < 0.60 cm², and 0.20 to < 0.40 cm²).

RESULTS

Overall, 77,890 (65%) patients with mild to-moderate and 4262 (4%) with severe MR were compared with 37,489 (31%) patients without MR. Patients with mild-to-moderate and severe MR presented significantly lower mPG (ΔmPG [95%CI] - 1.694 mmHg [- 2.123 to - 1.265], p < 0.0001 and - 6.954 mmHg [- 7.725 to - 6.183], p < 0.0001, respectively), that increased with LVEF impairment. Conversely, AVA did not differ (severe versus no MR: ΔAVA [95%CI]: - 0.007cm² [- 0.023 to 0.009], p = 0.973). Increasing MR severity was associated with significant mPG reduction throughout all AVA strata, causing a low-gradient pattern, that manifested since the early stages of severe AS (LVEF > 50%: AVA 0.80 to 1.00 cm²; LVEF 31-50%: AVA 0.60 to 0.80 cm²).

CONCLUSIONS

In patients with severe AS, concomitant MR is common, contributes to the onset of a low-gradient AS pattern, and affects the diagnostic accuracy of flow-dependent AVA measurements. In this setting, a multimodality, AVA-centric approach should be implemented. In patients with severe aortic stenosis, concomitant mitral regurgitation contributes to the onset of a low-gradient pattern, warranting a multimodality, and AVA-centric diagnostic approach.

Evaluating the effect of multivalvular disease on mortality after transcatheter aortic valve replacement for aortic stenosis: a meta-analysis and systematic review

Aims: To determine the prognosis of multivalvular disease in patients undergoing transcatheter aortic valve replacement (TAVR) for severe aortic stenosis. Methods: Patients undergoing TAVR for aortic stenosis with covariate-adjusted risk of mortality associated with concomitant valve disease (mitral regurgitation [MR], mitral stenosis [MS] or tricuspid regurgitation [TR]) were included. Results: Moderate-to-severe MR was associated with increased mortality at 30 days (hazard ratio [HR]: 1.60; 95% CI: 1.11-2.30; p = 0.01) and 1 year (HR: 1.87; 95% CI: 1.22-2.87; p = 0.004). The presence of all-grade MS did not impact 30-day or 1-year mortality (HR, 30 days: 1.60; 95% CI: 0.71-3.63; p = 0.26; and HR, 1 year: 1.90; 95% CI: 0.98-3.69; p = 0.06); however, an increased risk of 1-year mortality (HR: 1.67; 95% CI: 1.03-2.70; p = 0.04) was observed with severe MS compared with no MS. Moderate-to-severe TR had a higher risk of all-cause mortality at 1 year (HR: 1.49; 95% CI: 1.24-1.78; p < 0.001) compared with no or mild TR. Conclusion: Moderate-to-severe MR or TR, and severe MS, significantly increase mid-term mortality after TAVR.

Futility in Transcatheter Aortic Valve Implantation: A Search for Clarity

Although transcatheter aortic valve implantation (TAVI) has revolutionised the landscape of treatment for aortic stenosis, there exists a cohort of patients where TAVI is deemed futile. Among the pivotal high-risk trials, one-third to half of patients either died or received no symptomatic benefit from the procedure at 1 year. Futility of TAVI results in the unnecessary exposure of risk for patients and inefficient resource utilisation for healthcare services. Several cardiac and extra-cardiac conditions and frailty increase the risk of mortality despite TAVI. Among the survivors, these comorbidities can inhibit improvements in symptoms and quality of life. However, certain conditions are reversible with TAVI (e.g. functional mitral regurgitation), attenuating the risk and improving outcomes. Quantification of disease severity, identification of reversible factors and a systematic evaluation of frailty can substantially improve risk stratification and outcomes. This review examines the contribution of pre-existing comorbidities towards futility in TAVI and suggests a systematic approach to guide patient evaluation.

Mixed-Valve Disease: Management of Patients with Aortic Stenosis and Mitral Regurgitation: Thresholds for Surgery Versus Percutaneous Therapies

Significant mitral regurgitation (MR), frequently seen in the presence of severe aortic stenosis (AS), results in an association that negatively affects prognosis and imposes particular challenges for both the assessment of the severity of valvular lesions and decisions regarding treatment allocation. This article reviews the available literature with regards to the assessment of MR and AS in the presence of both; surgical management and results in patients with concomitant AS and MR; the effect of MR on outcomes in patients undergoing transcatheter aortic valve replacement; the effect of transcatheter aortic valve replacement on MR severity; and percutaneous treatment for MR after transcatheter aortic valve implantation. The authors aim to provide assistance in the decision-making process to treat patients with either a higher-risk double-valve procedure or a simpler, but perhaps incomplete, single-valve option.

Managing the patient undergoing transcatheter aortic valve replacement with ongoing mitral regurgitation

INTRODUCTION

Significant mitral regurgitation (MR) frequently coexists in patients with severe symptomatic aortic stenosis undergoing transcatheter aortic valve replacement (TAVR). These patients have worse clinical outcomes than those with non-significant MR, especially if MR persists after treatment of the aortic stenosis. The optimal treatment approach for this challenging high-risk population is not well defined.

AREAS COVERED

This review aims to present the current literature on concomitant significant MR in the TAVR population, and to provide a comprehensive algorithmic approach for clinical decision-making in this challenging cohort of patients.

EXPERT OPINION

Concomitant mitral and aortic valve disease is a complex clinical entity. An exhaustive and comprehensive assessment of patient's clinical characteristics and mitral valve anatomy and function is required in order to assess the surgical risk, predict the MR response after AVR and evaluate the feasibility of percutaneous MV treatment if necessary. Further developments in transcatheter techniques will expand the indications for double valve treatment in operable and inoperable patients with concomitant significant MR and aortic stenosis.

A guide for pre-procedural imaging for transcatheter aortic valve replacement patients

Safe and accurate pre-procedural assessment of cardiovascular anatomy, physiology, and pathophysiology prior to TAVR procedures can mean the difference between success and catastrophic failure. It is imperative that clinical care team members share a basic understanding of the preprocedural imaging technologies available for optimizing the care of TAVR patients. Herein, we review current imaging technology for assessing the anatomy, physiology, and pathophysiology of the aortic valvular complex, ventricular function, and peripheral vasculature, including echocardiography, cardiac catheterization, cardiac computed tomography, and cardiac magnetic resonance prior to a TAVR procedure. The authorship includes cardiac-trained anesthesiologists, anesthesiologists with expertise in pre-procedural cardiac assessment and optimization, and interventional cardiologists with expertise in cardiovascular imaging prior to TAVRs. Improving the understanding of all team members will undoubtedly translate into safer, more coordinated patient care.

Challenges in pulmonary hypertension associated with left heart disease

Introduction: Pulmonary hypertension (PH) secondary to left-sided heart disease (Group 2 PH) is a frequent complication of heart failure (HF) and is a heterogeneous phenotypic disorder that worsens exercise capacity, increases risk for hospitalization and survival independent of left ventricular ejection fraction (LVEF) or stage of HF. Areas covered: In this review, an update of the current knowledge and some potential challenges about the pathophysiology and treatments of group 2 PH in patients with HF of either preserved or reduced ejection fraction are provided. Also, this review discusses the epidemiology and provides hints for the optimal evaluation and diagnosis of these patients to prevent misclassification of their pulmonary hypertension. Expert opinion: There are many of areas lacking knowledge and understanding in the field of pulmonary hypertension associated to left heart disease (PH-LHD) that should be addressed in the future. Further research should be performed, in terms of pathobiology, and understanding the predisposition (genetic susceptibility and contributing factors) of the different phenotypes of this disorder. More clinical trials targeting new therapeutic options and specific PH therapies are warranted to help this increasing important patient group as the current guidelines recommend to only treat the underlying left-sided heart disease.

Transcatheter Aortic Valve Replacement and Concomitant Mitral Regurgitation

Mitral regurgitation frequently coexists in patients with severe aortic stenosis. Patients with moderate to severe mitral regurgitation at the time of transcatheter aortic valve replacement are at increased risk of future adverse events. Whether concomitant mitral regurgitation is independently associated with worse outcomes after TAVR remains a matter of debate. The optimal therapeutic strategy in these patients-TAVR with evidence-based heart failure therapy, combined TAVR and transcatheter mitral valve intervention, or staged transcatheter therapies-is ill-defined, and guideline-based recommendations in patients at increased risk for open heart surgery are lacking. Hence, a thorough evaluation of the aortic and mitral valve anatomy and function, along with an in-depth assessment of the patients' baseline risk profile, provides the basis for an individualized treatment approach. The aim of this review is therefore to give an overview of the current literature on mitral regurgitation in TAVR, focusing on different diagnostic and therapeutic strategies and optimal clinical decision making.

Successful Treatment of Mitral Regurgitation after Transapical Transcatheter Aortic Valve Implantation by Percutaneous Edge-to-edge Mitral Valve Repair (MitraClip®) -The First Combination Therapy Performed in Japan

A 75-year old man with a history of inferior myocardial infarction was admitted with symptoms of progressive heart failure 3 months after undergoing transapical transcatheter aortic valve implantation (TAVI). Echocardiography revealed severe mitral regurgitation (MR) caused by posterior leaflet tethering, without traumatic injury of the mitral valve or chordae. The patient was successfully treated by percutaneous edge-to-edge mitral valve repair (MitraClip^®). This case highlights the role of MitraClip^® in high-risk patients suffering from MR, and suggests that apical contractile loss or adhesion caused by apical puncture and suturing in transapical TAVI may be one of the mechanisms of worsening MR.

Immediate increase of cardiac output after percutaneous mitral valve repair (PMVR) determined by echocardiographic and invasive parameters: Patzelt: Increase of cardiac output after PMVR

BACKGROUND

Successful percutaneous mitral valve repair (PMVR) in patients with severe mitral regurgitation (MR) causes changes in hemodynamics. Echocardiographic calculation of cardiac output (CO) has not been evaluated in the setting of PMVR, so far. Here we evaluated hemodynamics before and after PMVR with the MitraClip system using pulmonary artery catheterization, transthoracic (TTE) and transesophageal (TEE) echocardiography.

METHODS

101 patients with severe MR not eligible for conventional surgery underwent PMVR. Hemodynamic parameters were determined during and after the intervention. We evaluated changes in CO and pulmonary artery systolic pressure before and after PMVR. CO was determined with invasive parameters using the Fick method (COi) and by a combination of TTE and TEE (COe).

RESULTS

All patients had successful clip implantation, which was associated with increased COi (from 4.6±1.4l/min to 5.4±1.6l/min, p<0.001). Furthermore, pulmonary artery systolic pressure (PASP) showed a significant decrease after PMVR (47.6±16.1 before, 44.7±15.5mmHg after, p=0.01). In accordance with invasive measurements, COe increased significantly (COe from 4.3±1.7l/min to 4.8±1.7l/min, p=0.003). Comparing both methods to calculate CO, we observed good agreement between COi and COe using Bland Altman plots.

CONCLUSIONS

CO increased significantly after PMVR as determined by echocardiography based and invasive calculation of hemodynamics during PMVR. COe shows good agreement with COi before and after the intervention and, thus, represents a potential non-invasive method to determine CO in patients with MR not accessible by conventional surgery.

Echocardiographic pulmonary hypertension probability is associated with clinical outcomes after transcatheter aortic valve implantation

AIMS

Pulmonary hypertension (PH) is associated with mortality after transcatheter aortic valve implantation (TAVI). However, diagnosis based on tricuspid regurgitant velocity (TRV) is often inaccurate and unreliable. The updated PH guidelines introduced a PH probability grading implementing additional PH signs on transthoracic echocardiography (TTE), from which we aimed to analyse its effects on clinical outcomes in patients undergoing TAVI.

METHODS AND RESULTS

We included 591 consecutive patients (mean age 80.2±8.4years, 58.0% female, mean STS risk score 6.2±3.8%) undergoing TAVI. Patients were divided into "low" (n=270; TRV ≤2.8m/s without additional PH signs), "intermediate" (n=131; TRV ≤2.8m/s with additional PH signs, or TRV 2.9-3.4m/s without additional PH signs), and "high" PH probability (n=190; TRV 2.9-3.4m/s with additional PH signs, or TRV >3.4m/s). The overall 30-day and 2-year mortality rates were 10.2% and 33.8%, respectively. "High" PH probability was an independent predictor of mortality at 30days (HR 3.68, 95% CI 2.03 to 6.67, p<0.01) and 2years (HR 2.19, 95% CI 1.57 to 3.04, p<0.01), compared to "low" PH probability. The "intermediate" group did not show an increased risk. The presence of additional PH signs resulted in a significantly higher mortality at 30days (19.6% vs. 5.1%, p<0.01) and two years (54.2% vs. 22.5%, p<0.01).

CONCLUSIONS

The updated echocardiographic PH probability model incorporating additional PH signs independently predicts early and late mortality after TAVI. Additional PH signs are of great value in assessing one's risks since its presence is strongly associated with early and late mortality.

Effect of resting heart rate on two-year clinical outcomes of high-risk patients with severe symptomatic aortic stenosis undergoing transcatheter aortic valve implantation

AIMS

Resting heart rate (HRate) is a modifiable risk factor among patients with cardiovascular disease, including aortic stenosis (AS). However, the effect of resting HRate on clinical outcomes of patients with severe symptomatic AS undergoing transcatheter aortic valve implantation (TAVI) is unknown. Our aim was therefore to assess the effect of resting HRate on clinical outcomes among high-risk patients with symptomatic severe AS in normal sinus rhythm (NSR) undergoing TAVI.

METHODS AND RESULTS

Of 606 consecutive patients undergoing TAVI, 349 (57.6%) with severe AS and a baseline 12-lead electrocardiogram (ECG) showing NSR undergoing TAVI were analysed. Patients were dichotomised into low HRate (LHR; <77 beats per minute [bpm]) and high HRate (HHR; ≥77 bpm) groups. The primary endpoint was all-cause mortality at two years. As compared with baseline LHR, no significant differences in all-cause mortality at two years (adjusted [adj] hazard ratio [HR] 1.23, p=0.40) were observed among patients with baseline HHR. Of 197 patients with available discharge ECGs remaining in NSR, mean HRate significantly increased among LHR patients (∆HRate 8.35, p<0.001) but decreased among HHR patients (∆HRate -4.88, p<0.001). On thirty-day landmark analysis, discharge HHR was significantly associated with two-year all-cause mortality (HR 2.30, 95% CI: 1.16-4.56, p=0.017), but not after extensive adjustment for comorbidities (adj HR 2.01, 95% CI: 0.98-4.09, p=0.056). A significant interaction for two-year mortality (p-interaction 0.021) was observed on landmark analysis for discharge, but not baseline, HHR.

CONCLUSIONS

Baseline and discharge resting HRate were not associated with adverse outcomes after TAVI.

Impact of Mitral Regurgitation on Clinical Outcomes After Transcatheter Aortic Valve Implantation

Severe aortic stenosis (AS) and mitral regurgitation (MR) are the two most common valvular lesions referred for surgical intervention in Europe and frequently co-exist. In patients with both severe AS and significant MR referred for surgical aortic valve replacement (SAVR), a concomitant mitral valve intervention is typically performed if the MR is severe, despite the higher associated perioperative risk. The management of moderate MR among SAVR patients is controversial and depends on a number of factors including MR aetiology (i.e., organic versus functional MR), feasibility of repair and patient risk profile. Moderate or severe MR is present in up to one-third of patients undergoing transcatheter aortic valve implantation (TAVI), is mainly of functional aetiology and is typically left untreated. Although data are conflicting, a growing body of evidence suggests that significant MR exerts an adverse effect on both short- and long-term clinical outcomes after TAVI. Moderate or severe MR improves in just over half of patients following TAVI and recent data suggest MR is more likely to improve among patients receiving a balloon-expandable as compared with a self-expandable transcatheter heart valve.

Optimizing clinical outcomes of transcatheter aortic valve implantation patients with comorbidities

Transcatheter aortic valve implantation (TAVI) has revolutionized the management of high-risk or inoperable patients presenting with symptomatic severe aortic stenosis (AS). There are several factors to consider to optimize patient outcomes from TAVI. Before TAVI, patient selection is key and an understanding the effects of common comorbidities on outcomes after TAVI is critical. Some comorbidities share common risk factors with AS (e.g. coronary artery disease), others are directly or indirectly caused or exacerbated by severe AS (e.g. atrial fibrillation, pulmonary hypertension, mitral regurgitation, tricuspid regurgitation and right ventricular dysfunction), whereas others are not directly related to severe AS (e.g. chronic kidney disease and chronic lung disease). Choice of transcatheter heart valve prosthesis, vascular access route and mode of anesthesia are important considerations during TAVI. New onset conduction disturbances and arrhythmias remain a vexing issue after TAVI. The aim of the present review is to provide an overview of these issues.