The Incremental Value of Valvuloarterial Impedance in Evaluating the Results of Transcatheter Aortic Valve Implantation in Symptomatic Aortic Stenosis

Comparative Analysis of Perceval and Conventional Bovine Bioprosthetic Valves in Aortic Valve Replacement: Hemodynamics, Reverse Remodeling, and Long-Term Outcomes

Background/Objectives: Surgical aortic valve replacement effectively relieves left ventricular afterload and promotes reverse remodeling in patients with severe aortic stenosis. The Perceval prosthesis offers a hybrid approach, combining complete annular decalcification with sutureless deployment. This design allows for reduced operative times and potentially larger effective orifice areas. However, comparative data with conventional stented bioprosthetic valves remain limited, particularly regarding reverse remodeling, hemodynamic performance, and long-term clinical outcomes. Methods: In this retrospective cohort study, 115 patients underwent aortic valve replacement with either the Perceval valve (n = 44) or conventional stented bovine pericardial valves (n = 71). Results: The Perceval group showed a 100% procedural success rate with no in-hospital mortality, significantly shorter cardiopulmonary bypass and cross-clamp times, larger effective orifice areas, and a lower incidence of patient-prosthesis mismatch. Both groups demonstrated favorable left ventricular mass regression and reverse remodeling. The rates of paravalvular leakage, permanent pacemaker implantation, and redo aortic valve replacement were comparable between groups. Multivariate Cox regression identified the follow-up indexed left ventricular mass as an independent predictor of major adverse cardiac and cerebral events. Conclusions: In this study, the Perceval valve was associated with promising hemodynamic characteristics and procedural efficiencies, particularly in cases with small aortic annuli and during minimally invasive procedures. The valve was associated with reverse ventricular remodeling and clinical outcomes that appeared similar to those of conventional stented bioprostheses. These observations suggest it may represent a potential alternative option for surgical aortic valve replacement in appropriate clinical scenarios. However, randomized control trials are needed to confirm these associations.

Reducing Left Ventricular Wall Stress through Aortic Valve Enlargement via Transcatheter Aortic Valve Implantation in Severe Aortic Stenosis

Background: In aortic stenosis, the left ventricle exerts additional force to pump blood through the narrowed aortic valve into the downstream arterial vasculature. Adaptive hypertrophy helps to maintain wall stress homeostasis but at the expense of impaired compliance. Advanced ventricular deformation impacts the extent of functional recovery benefits achieved through transcatheter aortic valve implantation. Methods and Results: Subgroups were stratified based on output, with low-flow severe aortic stenosis defined as stroke volume index <35 mL· m-2. Before intervention, the low-flow subgroup exhibited worse effective orifice area index and arterial and global impedance, along with thinner wall thickness and larger chamber volume marginally. LV performance, including stroke volume index, ventricular elastance, and ventricular-arterial coupling, were notably inferior, consistent with worse adverse remodeling. Although the effective orifice area index was similarly augmented after TAVI, inferior recovery benefits were noted. Persistently higher wall stress and energy consumption were observed, along with poorer ventricular-arterial coupling. These changes in wall stress showed an inverse relationship with alterations in wall thickness and were proportional to changes in dimension and volume. Additionally, they were proportional to changes in left ventricular end-systolic pressure, pressure-volume area, and ventricular-arterial coupling but inversely related to ventricular end-systolic elastance. Conclusions: The study revealed that aortic valve enlargement through transcatheter aortic valve implantation reduces left ventricular wall stress in severe aortic stenosis. The reduced recovery benefits in the low-flow subgroup were evident. Wall stress could serve as a marker of mechanical benefit after the intervention.

Differential Impact of Blood Pressure Control Targets on Epicardial Coronary Flow After Transcatheter Aortic Valve Replacement

Background

The cause for the association between increased cardiovascular mortality rates and lower blood pressure (BP) after aortic valve replacement (AVR) is unclear. This study aims to assess how the epicardial coronary flow (ECF) after AVR varies as BP levels are changed in the presence of a right coronary lesion.

Methods

The hemodynamics of a 3D printed aortic root model with a SAPIEN 3 26 deployed were evaluated in an in vitro left heart simulator under a range of varying systolic blood pressure (SBP) and diastolic blood pressure (DBP). ECF and the flow ratio index were calculated. Flow index value <0.8 was considered a threshold for ischemia.

Results

As SBP decreased, the average ECF decreased below the physiological coronary minimum at 120 mmHg. As DBP decreased, the average ECF was still maintained above the physiological minimum. The flow ratio index was >0.9 for SBP ≥130 mmHg. However, at an SBP of 120 mmHg, the flow ratio was 0.63 (p ≤ 0.0055). With decreasing DBP, no BP condition yielded a flow ratio index that was less than 0.91.

Conclusions

Reducing BP to the current recommended levels assigned for the general population after AVR in the presence of coronary artery disease may require reconsideration of levels and treatment priority. Additional studies are needed to fully understand the changes in ECF dynamics after AVR in the presence and absence of coronary artery disease.

Left ventricular reverse remodeling after transcatheter aortic valve implantation in patients with low-flow low-gradient aortic stenosis

OBJECTIVES

Left ventricular reverse remodeling (LVRR) is associated with improved outcome in patients with heart failure. Factors associated with and predictive of LVRR in patients with low-flow low-gradient aortic stenosis (LFLG AS) after transcatheter aortic valve implantation (TAVI) and its impact on outcome were assessed.

METHODS

Pre- and postprocedural left ventricular (LV) function and volume were investigated in 219 patients with LFLG. LVRR was defined as an absolute increase of ≥10% in LV ejection fraction (LVEF) and reduction of ≥15% in LV end-systolic volume (LVESV). The primary endpoint was the combination of all-cause mortality and rehospitalization for heart failure.

RESULTS

The mean LVEF was 35.0 ± 10.0%, with a stroke volume index (SVI) of 25.9 ± 6.0 mL/m2 and LVESV of 94.04 ± 46.0 mL. At a median of 5.2 months (interquartile range, 2.7-8.1 months), 77.2% (n = 169) of the patients showed echocardiographic evidence of LVRR. A multivariate model revealed three independent factors for LVRR after TAVI: SVI of <25 mL/m2 (hazard ratio [HR], 2.31; 95% confidence interval [CI], 1.08-3.58; p < 0.01), LVEF of <30% (HR, 2.76; 95% CI, 1.53-2.91; p < 0.01), and valvulo-arterial impedance (Zva) of <5 mmHg/mL/m2 (HR, 5.36; 95% CI, 1.80-15.98; p < 0.01). Patients without evidence of LVRR showed a significantly higher incidence of the 1-year combined endpoint (32 [64.0%] vs. 75 [44.4%], p < 0.01).

CONCLUSIONS

The majority of patients with LFLG AS show LVRR after TAVI, which is associated with favorable outcomes. An SVI of <25 mL/m2, LVEF of <30%, and Zva < 5mmHg/mL/m2 represent predictors of LVRR.

Using Augmented Mean Arterial Pressure to Identify High Mortality Risk Patients With Moderate Aortic Stenosis

OBJECTIVE

To study the usefulness of a novel echocardiographic marker, augmented mean arterial pressure (AugMAP = [(mean aortic valve gradient + systolic blood pressure) + (2 × diastolic blood pressure)] / 3), in identifying high-risk patients with moderate aortic stenosis (AS).

PATIENTS AND METHODS

Adults with moderate AS (aortic valve area, 1.0-1.5 cm2) at Mayo Clinic sites from January 1, 2010, through December 31, 2020, were identified. Baseline demographic, echocardiographic, and all-cause mortality data were retrieved. Patients were grouped into higher and lower AugMAP groups using a cutoff value of 80 mm Hg for analysis. Kaplan-Meier and Cox regression models were used to assess the performance of AugMAP.

RESULTS

A total of 4563 patients with moderate AS were included (mean ± SD age, 73.7±12.5 years; 60.5% men). Median follow-up was 2.5 years; 36.0% of patients died. The mean ± SD left ventricular ejection fraction (LVEF) was 60.1%±11.4%, and the mean ± SD AugMAP was 99.1±13.1 mm Hg. Patients in the lower AugMAP group, with either preserved or reduced LVEF, had significantly worse survival performance (all P<.001). Multivariate Cox regression showed that AugMAP (hazard ratio, 0.962; 95% CI, 0.942 to 0.981 per 5-mm Hg increase; P<.001) and AugMAP less than 80 mm Hg (hazard ratio, 1.477; 95% CI, 1.241 to 1.756; P<.001) were independently associated with all-cause mortality.

CONCLUSION

AugMAP is a simple and effective echocardiographic marker to identify high-risk patients with moderate AS independent of LVEF. It can potentially be used in the candidate selection process if moderate AS becomes indicated for aortic valve intervention in the future.

Transcatheter Aortic Valve Replacement Prognostication with Augmented Mean Arterial Pressure

BACKGROUND

Post-transcatheter aortic valve replacement (TAVR) patient outcome is an important research topic. To accurately assess post-TAVR mortality, we examined a family of new echo parameters (augmented systolic blood pressure (AugSBP) and arterial mean pressure (AugMAP)) derived from blood pressure and aortic valve gradients.

METHODS

Patients in the Mayo Clinic National Cardiovascular Diseases Registry-TAVR database who underwent TAVR between 1 January 2012 and 30 June 2017 were identified to retrieve baseline clinical, echocardiographic and mortality data. AugSBP, AugMAP and valvulo-arterial impedance (Zva) (Zva) were evaluated using Cox regression. Receiver operating characteristic curve analysis and the c-index were used to assess the model performance against the Society of Thoracic Surgeons (STS) risk score.

RESULTS

The final cohort contained 974 patients with a mean age of 81.4 ± 8.3 years old, and 56.6% were male. The mean STS risk score was 8.2 ± 5.2. The median follow-up duration was 354 days, and the one-year all-cause mortality rate was 14.2%. Both univariate and multivariate Cox regression showed that AugSBP and AugMAP parameters were independent predictors for intermediate-term post-TAVR mortality (all p < 0.0001). AugMAP1 < 102.5 mmHg was associated with a 3-fold-increased risk of all-cause mortality 1-year post-TAVR (hazard ratio 3.0, 95%confidence interval 2.0-4.5, p < 0.0001). A univariate model of AugMAP1 surpassed the STS score model in predicting intermediate-term post-TAVR mortality (area under the curve: 0.700 vs. 0.587, p = 0.005; c-index: 0.681 vs. 0.585, p = 0.001).

CONCLUSIONS

Augmented mean arterial pressure provides clinicians with a simple but effective approach to quickly identify patients at risk and potentially improve post-TAVR prognosis.

Extent of Left Ventricular Mass Regression and Impact of Global Left Ventricular Afterload on Cardiac Events and Mortality after Aortic Valve Replacement

Patient-prosthesis mismatch (PPM) causes a high transvalvular pressure gradient and residual left ventricular (LV) hypertrophy, consequently influencing long-term results. This study aimed to find the relationships between hemodynamic parameters and LV mass regression and determine the risk predictors of major adverse cardiovascular and cerebral events (MACCE) after aortic valve replacement (AVR) for aortic stenosis. Methods and Results: Preoperative and postoperative Doppler echocardiography data were evaluated for 120 patients after AVR. The patients' mean age was 67.7 years; 55% of the patients were male. Forty-four (37%) patients suffered from MACCE during a mean follow-up period of 3.6 ± 2 years. The following hemodynamic parameters at follow-up were associated with lower relative indexed LV mass (LVMI) regression: lower postoperative indexed effective orifice area, greater mean transvalvular pressure gradient (MPG), greater stroke work loss (SWL), and concentric or eccentric LV remodeling mode. The following hemodynamic parameters at follow-up were associated with a higher risk of MACCE: higher valvuloarterial impedance (Z_VA), greater SWL, greater MPG, greater relative wall thickness, greater LVMI, and hypertrophic LV remodeling mode. Lower relative LVMI regression was associated with a higher risk of MACCE (hazard ratio, 1.01: 95% confidence interval, 1.003-1.03). The corresponding cutoff of relative LVMI regression was -14%. Conclusions: Changes in hemodynamic parameters were independently associated with relative LVMI regression. Impaired reverse remodeling and persistent residual LV hypertrophy were independent risk predictors of MACCE. An LVMI regression lower than 14% indicated higher MACCE. A postoperative Z_VA greater than 3.5 mmHg/mL/m² was an independent risk predictor of cardiac events and mortality after AVR. Preventive strategies should be used at the time of the operation to avoid PPM.

New Evidence About Aortic Valve Stenosis and Cardiovascular Hemodynamics

Aortic stenosis (AS) is the most common degenerative valvular disease in western word. In patients with severe AS, small changes in aortic valve area can lead to large changes in hemodynamics. The correct understanding of cardiac hemodynamics and its interaction with vascular function is of paramount importance for correct identification of severe AS and to plan effective strategies for its treatment. In the current review with highlight the importance of pressure recovery phenomenon and valvular arterial impedance as novel tools in the evaluation of patients with aortic stenosis.

Impact of blood pressure on coronary perfusion and valvular hemodynamics after aortic valve replacement

OBJECTIVE

Our objective was to evaluate the impact of various blood pressures (BPs) on coronary perfusion and valvular hemodynamics following aortic valve replacement (AVR).

BACKGROUND

Lower systolic and diastolic (SBP/DBP) pressures from the recommended optimal target range of SBP < 120-130 mmHg and DBP < 80 mmHg after AVR have been independently associated with increased cardiovascular and all-cause mortality.

METHODS

The hemodynamic assessment of a 26 mm SAPIEN 3 transcatheter aortic valve (TAV), 29 mm Evolut R TAV, and 25 mm Magna Ease surgical aortic valve (SAV) was performed in a pulsed left heart simulator with varying SBP, DBP, and heart rate (HR) conditions (60 and 120 bpm) at 5 L/min cardiac output (CO). Average coronary flow (CF), effective orifice areas (EOAs), and valvulo-arterial impedance (Zva) were calculated.

RESULTS

At HR of 60 bpm, at SBP < 120 mmHg and DBP < 60 mmHg, CF decreased below the physiological lower limit with several different valves. Zva and EOA were found to increase and decrease respectively with increasing SBP and DBP. The same results were found with an HR of 120 bpm. The trends of CF variation with BP were similar in all valves however the drop below the lower physiological CF limit was valve dependent.

CONCLUSION

In a controlled in vitro system, with different aortic valve prostheses in place, CF decreased below the physiologic minimum when SBP and DBP were in the range targeted by blood pressure guidelines. Combined with recent observations from patients treated with AVR, these findings underscore the need for additional studies to identify the optimal BP in patients treated with AVR for AS.

Arterial biomarkers in the evaluation, management and prognosis of aortic stenosis

Degenerative aortic valve stenosis is the most common primary valve disease and a significant cause of cardiovascular morbidity and mortality. In an era when new techniques for the management of aortic stenosis are gaining ground, the understanding of this disease is more important than ever to optimize treatment. So far, the focus has been placed on the assessment of the valve itself. However, the role that the arterial system plays in the pathogenesis and natural history of the disease needs to be further elucidated. Arteriosclerosis, when it coexists with a stenotic valve, augments the load posed on the left ventricle contributing to greater impairment of cardiovascular function. Arterial stiffness, a well-established predictor for cardiovascular disease and all-cause mortality, could play a role in the prognosis and quality of life of this population. Several studies using a variety of indices to assess arterial stiffness have tried to address the potential utility of arterial function assessment in the case of aortic stenosis. Importantly, reliable data identify a prognostic role of arterial biomarkers in aortic stenosis and stress their possible use to optimize timing and method of treatment. This review aims at summarizing the existing knowledge on the interplay between the heart and the vessels in the presence of degenerative aortic stenosis, prior, upon and after interventional management. Further, it discusses the evidence supporting the potential clinical application of arterial biomarkers for the assessment of progression, severity, management and prognosis of aortic stenosis.

Low Relative Valve Load is Associated With Paradoxical Low-Flow Aortic Stenosis Despite Preserved Left Ventricular Ejection Fraction and Adverse Clinical Outcomes

BACKGROUND

Paradoxical low-flow (LF) severe aortic stenosis (AS) despite preserved left ventricular (LV) ejection fraction (LVEF) has been shown to be distinct from normal-flow (NF) AS, with a poorer prognosis. Relative valve load (RVL) is a novel echocardiographic haemodynamic index based on the ratio of transaortic mean pressure gradient to the global valvulo-arterial impedance (Zva) in order to estimate the contribution of the valvular afterload to the global LV load. We aimed to determine the usefulness of RVL in LF AS versus NF AS.

METHOD

A total of 450 consecutive patients with medically managed severe AS (aortic valve area <1.0 cm²) with preserved LVEF (>50%) were studied. Patients were divided into LF (stroke volume index <35 mL/m²) or NF, and high RVL or low RVL. Baseline clinical and echocardiographic profiles, as well as clinical outcomes, were compared.

RESULTS

There were 149 (33.1%) patients with LF. Despite higher global impedance in LF (Zva 6.3±2.4 vs 3.9±0.9 mmHg/mL/m²; p<0.001) compared with NF, the RVL in LF AS was significantly lower (5.4±2.7 vs 9.8±5.1 mL/m²; p<0.001). On multivariable analysis, low RVL (≤7.51) remained independently associated with poor clinical outcomes on Cox regression (hazard ratio, 1.31; 95% confidence interval, 1.03-1.68), with 53.2% sensitivity and 70.3% specificity. This was comparable to other prognostic indices in AS. Kaplan-Meier curves demonstrated that low RVL was associated with increased mortality.

CONCLUSIONS

Increased systemic arterial afterload may be important in the pathophysiology of LF AS. Low RVL was an independent predictor of poor clinical outcomes in medically managed severe AS. There may be a greater role in the attenuation of systemic arterial afterload in AS to improve outcomes.

Bedside Renal Doppler Ultrasonography and Acute Kidney Injury after TAVR

Acute kidney injury (AKI) following transcatheter aortic valve replacement (TAVR) is associated with a dismal prognosis. Elevated renal resistive index (RRI), through renal Doppler ultrasound (RDU) evaluation, has been associated with AKI development and increased systemic arterial stiffness. Our pilot study aimed to investigate the performance of Doppler based RRI to predict AKI and outcomes in TAVR patients. From May 2018 to May 2019, 100 patients with severe aortic stenosis were prospectively enrolled for TAVR and concomitant RDU evaluation at our institution (Nouvel Hôpital Civil, Strasbourg University, France). AKI by serum Creatinine (sCr-AKI) was defined according to the VARC-2 definition and AKI by serum Cystatin C (sCyC-AKI) was defined as an sCyC increase of greater than 15% with baseline value. Concomitant RRI measurements as well as renal and systemic hemodynamic parameters were recorded before, one day, and three days after TAVR. It was found that 10% of patients presented with AKI_sCr and AKI_sCyC. The whole cohort showed higher baseline RRI values (0.76 ± 0.7) compared to normal known and accepted values. AKI_sCyC had significant higher post-procedural RRI one day (Day 1) after TAVR (0.83 ± 0.1 vs. 0.77 ± 0.6, CI 95%, p = 0.005). AUC for AKI_sCyC was 0.766 and a RRI cut-off value of ≥ 0.795 had the most optimal sensitivity/specificity (80/62%) combination. By univariate Cox analysis, Mehran Risk Score, higher baseline right atrial pressure at baseline > 0.8 RRI values one day after TAVR (HR 6.5 (95% CI 1.3-32.9; p = 0.021) but not RRI at baseline were significant predictors of AKI_sCyC. Importantly, no significant impact of baseline biological parameters, renal or systemic parameters could be demonstrated. Doppler-based RRI can be helpful for the non-invasive assessment of AKI development after TAVR.

Impact of Valvulo-Arterial Impedance on Long-Term Quality of Life and Exercise Performance After Transcatheter Aortic Valve Replacement

BACKGROUND

In aortic stenosis, valvulo-arterial impedance (Zva) estimates the overall left ventricular afterload (valve and arterial component). We investigated the association of Zva (≥5 versus <5 mm Hg mL^-1 m^-2) on quality of life (QOL) and exercise performance (EP) ≥1 year after transcatheter aortic valve replacement (TAVR).

METHODS

The study population consists of 250 TAVR patients in whom baseline Zva and follow-up QOL was prospectively assessed using EuroQOL-5-dimensions instruments; EP was assessed in 192 patients who survived ≥1 year after TAVR using questionnaires related to daily activities. In 124 patients, Zva at 1-year was also available and was used to study the change in Zva (baseline to 1 year) on QOL/EP.

RESULTS

Elevated baseline Zva was present in 125 patients (50%). At a median of 28 (IQR, 17-40) months, patients with elevated baseline Zva were more limited in mobility (88% versus 71%; P=0.004), self-care (40% versus 25%; P=0.019), and independent daily activities (taking a shower: 53% versus 38%, P=0.030; walking 100 meter: 76% versus 54%, P=0.001; and walking stairs: 74% versus 54%, P=0.011). By multivariable analysis, elevated Zva predicted unfavorable QOL (lower EuroQOL-5-dimensions-Utility Index, odds ratio, 1.98; CI, 1.15-3.41) and unfavorable EP (any limitation in ≥3 daily activities, odds ratio, 2.55; CI, 1.41-4.62). After TAVR, the proportion of patients with elevated Zva fell from 50% to 21% and remained 21% at 1 year and was found to be associated with more limitations in mobility, self-care, and daily activities compared with patients with Zva <5 mm Hg mL^-1 m^-2.

CONCLUSIONS

Elevated Zva was seen in half of patients and predicted unfavorable long-term QOL and EP. At 1 year after TAVR, the prevalence of elevated Zva was 21% but remained associated with poor QOL/EP.

Association between valvuloarterial impedance after transcatheter aortic valve implantation and 2-year mortality in elderly patients with severe symptomatic aortic stenosis: the OCEAN-TAVI registry

Pre-procedural valvuloarterial impedance (Zva) is considered as a useful predictor of mortality in patients diagnosed as having severe aortic stenosis (AS) who undergo transcatheter aortic valve implantation (TAVI). However, the prognostic significance of post-procedural Zva remains unclear. We aimed to evaluate the prognostic significance of Zva after TAVI. We retrospectively analyzed the clinical and echocardiographic data of 1004 consecutive elderly patients (median 84 years old, 27.5% men) who underwent TAVI for severe symptomatic AS. Zva was calculated after TAVI, and patients were divided into three groups based on tertile values: the high [> 3.33 (n = 335)], intermediate [2.49-3.33 (n = 334)], and low Zva groups [< 2.49 (n = 335)]. The estimated 2-year all-cause and cardiovascular mortalities using Kaplan-Meier analysis were 16.2% [95% confidence interval (CI) 11.8-20.4] and 5.9% (95% CI 3.2-8.6), respectively. There were no significant intergroup differences in each endpoint (long-rank p = 0.518 for all-cause mortality, p = 0.757 for cardiovascular mortality). Multivariable Cox regression analyzes with adjustments of patient characteristics and medications showed that the post-procedural Zva was not associated with the 2-year all-cause mortality [intermediate Zva group versus (vs.) low Zva group: adjusted hazard ratio (aHR) = 1.34, 95% CI 0.75-2.40, p = 0.316; high Zva group vs. low Zva group: aHR = 1.17, 95% CI 0.64-2.16, p = 0.613] and cardiovascular mortality (intermediate Zva group vs. low Zva group: aHR = 1.50, 95% CI 0.56-4.06, p = 0.421; high Zva group vs. low Zva group: aHR = 1.25, 95% CI 0.43-3.65, p = 0.682). Our results suggest that post-procedural Zva was not associated with 2-year all-cause or cardiovascular mortalities in patients with severe symptomatic AS who underwent TAVI.

Hypertension and transcatheter aortic valve replacement: parallel or series?

Aortic stenosis (AS) is the most common valvular heart disease in the elderly and it causes significant morbidity and mortality. Hypertension is also highly prevalent in elderly patients with AS, and AS patients with hypertension have worse outcomes. Accurate assessment of AS severity and understanding its relationship with arterial compliance has become increasingly important as the options for valve management, particularly transcatheter interventions, have grown. The parameters used for quantifying stenosis severity have traditionally mainly focused on the valve itself. However, AS is now recognized as a systemic disease involving aging ventricles and stiff arteries rather than one limited solely to the valve. Over the last decade, valvuloarterial impedance, a measure of global ventricular load, has contributed to our understanding of the pathophysiology and course of AS in heterogeneous patients, even when segregated by symptoms and severity. This review summarizes our growing understanding of the interplay between ventricle, valve, and vessel, with a particular emphasis on downstream vascular changes after transcatheter aortic valve replacement and the role of valvuloarterial impedance in predicting left ventricular changes and prognosis in patients with various transvalvular flow patterns.

A novel echocardiographic hemodynamic index for predicting outcome of aortic stenosis patients following transcatheter aortic valve replacement

Objective

Transcatheter aortic valve replacement (TAVR) reduces left ventricular (LV) afterload and improves prognosis in aortic stenosis (AS) patients. However, LV afterload consists of both valvular and arterial loads, and the benefits of TAVR may be attenuated if the arterial load dominates. We proposed a new hemodynamic index, the Relative Valve Load (RVL), a ratio of mean gradient (MG) and valvuloarterial impedance (Zva), to describe the relative contribution of the valvular load to the global LV load, and examined whether RVL predicted patient outcome following TAVR.

Methods

A total of 258 patients with symptomatic severe AS (indexed aortic valve area (AVA)<0.6cm²/m², AR≤2+) underwent successful TAVR at the University of Ottawa Heart Institute and had clinical follow-up to 1-year post-TAVR. Pre-TAVR MG, AVA, percent stroke work loss (%SWL), Zva and RVL were measured by echocardiography. The primary endpoint was all cause mortality at 1-year post TAVR.

Results

There were 53 deaths (20.5%) at 1-year. RVL≤7.95ml/m² had a sensitivity of 60.4% and specificity of 75.1% for identifying all cause mortality at 1-year post-TAVR and provided better specificity than MG<40 mmHg, AVA>0.75cm², %SWL≤25% and Zva>5mmHg/ml/m² despite equivalent or better sensitivity. In multivariable Cox analysis, RVL≤7.95ml/m² was an independent predictor of all cause mortality (HR 3.2, CI 1.8–5.9; p<0.0001). RVL≤7.95ml/m² was predictive of all cause mortality in both low flow and normal flow severe AS.

Conclusions

RVL is a strong predictor of all-cause mortality in severe AS patients undergoing TAVR. A pre-procedural RVL≤7.95ml/m² identifies AS patients at increased risk of death despite TAVR and may assist with decision making on the benefits of TAVR.

Dynamic changes in aortic impedance after transcatheter aortic valve replacement and its impact on exploratory outcome

Valvulo-arterial impedance (Zva) has been shown to predict worse outcome in medically managed aortic stenosis (AS) patients. We aimed to investigate the association between Zva and left ventricular (LV) adaptation and to explore the predictive value of Zva for cardiac functional recovery and outcome after transcatheter aortic valve replacement (TAVR). We prospectively enrolled 128 patients with AS who underwent TAVR. Zva was calculated as: (systolic blood pressure + mean transaortic gradient)/stroke volume index). Echocardiographic assessment occurred at baseline, 1-month and 1-year after TAVR. The primary endpoints were to investigate associations between Zva and global longitudinal strain (GLS) at baseline as well as GLS change after TAVR. The secondary was to compare all-cause mortality after TAVR between patients with pre-defined Zva (=5 mmHg m²/ml), stroke volume index (=35 ml/m²), and GLS (=-15%) cutoffs. The mean GLS was reduced (-13.0 ± 3.2%). The mean Zva was 5.2 ± 1.6 mmHg*m²/ml with 55% of values ≥5.0 mmHg*m²/ml, considered to be abnormally high. Higher Zva correlated with worse GLS (r = -0.33, p < 0.001). After TAVR, Zva decreased significantly (5.1 ± 1.6 vs. 4.5 ± 1.6 mmHg*m²/ml, p = 0.001). A reduction of Zva at 1-month was associated with GLS improvement at 1-month (r = -0.31, p = 0.001) and at 1-year (r = -0.36 and p = 0.001). By Kaplan-Meier analysis, patients with higher Zva at baseline had higher mortality (Log-rank p = 0.046), while stroke volume index and GLS did not differentiate outcome (Log-rank p = 0.09 and 0.25, respectively). As a conclusion, Zva is correlated with GLS in AS as well as GLS improvement after TAVR. Furthermore, a high baseline Zva may have an additional impact to traditional parameters on predicting worse mortality after TAVR.

Evolving new concepts in the assessment of aortic stenosis

Echocardiography has been pivotal in evaluating aortic stenosis (AS) over the past several decades. Recent experience has shown a wide spectrum in the clinical presentation of AS. A better understanding of the underlying hemodynamic principles has resulted in emergence of new subtypes of AS. New treatment modalities have also been introduced, requiring precise evaluation of aortic valve (AV) pathology for implementation of these therapies. This review will discuss new concepts and indices in the use of echocardiography in patients with AS. Specifically, we will address the hemodynamic characteristics, clinical presentation, and management of normal-flow, high-gradient; paradoxical low-flow, low-gradient; and classical low-flow, low-gradient aortic stenoses.

Impact of Valvuloarterial Impedance on Concentric Remodeling in Aortic Stenosis and Its Regression after Valve Replacement

Background

Left ventricle (LV) in patients with aortic stenosis (AS) faces a double hemodynamic load incorporating both valvular stenosis and reduced systemic arterial compliance (SAC). This study aimed to evaluate the impact of global LV afterload on LV hypertrophy (LVH) before and after aortic valve replacement (AVR).

Methods

The study cohort included 453 patients (247 males; mean age, 64 ± 11 years) who underwent AVR. Pre- and post-AVR echocardiographic examinations were retrospectively analyzed including an index of valvuloarterial impedance (Z_VA) and LV mass index/LV end-diastolic volume index (LVMI/LVEDVI) as a parameter of LVH.

Results

Pre-AVR LVMI/LVEDVI was 2.7 ± 0.9 g/mL with an aortic valve area (AVA) of 0.6 ± 0.2 cm². Z_VA was 5.9 ± 1.9 mm Hg/mL/m² and showed a stronger correlation (β = 0.601, p < 0.001) with pre-AVR LVMI/LVEDVI than indexed AVA (β = 0.061, p = 0.19), transvalvular peak velocity (β = 0.211, p < 0.001). During a median follow-up of 3.5 years, patients had a 18.8 ± 10.4% decrease in the LV geometry index with a decrease in SAC from 1.20 ± 0.48 to 1.00 ± 0.38 mL/m²/mm Hg (p < 0.001). Pre-AVR LV ejection fraction (r = 0.284, p < 0.001) and Z_VA (r = 0.523, p < 0.001) were independent factors associated with LVH regression in 322 patients with follow-up duration >1 year after AVR.

Conclusion

Z_VA is a major determinant of concentric remodeling in AS before AVR and LVH regression after AVR, which should be incorporated in routine evaluation of AS.

Intensive care unit management of transcatheter aortic valve recipients

Severe aortic stenosis is an increasingly prevalent disease that continues to be associated with significant mortality. Transcatheter aortic valve replacements have been used as an alternative to surgical aortic valve replacement in high-risk patients with multiple comorbidities. In this review, we discuss postoperative considerations pertinent to the successful management of these complicated patients in the intensive care unit.

Transcatheter aortic valve implantation and intraoperative left ventricular function: a myocardial tissue Doppler imaging study

OBJECTIVE

Transcatheter aortic valve implantation in patients turned down for surgical aortic valve replacement is a high-risk procedure. Severe aortic stenosis is associated with impaired left ventricular longitudinal motion, and myocardial peak systolic velocity is a measure of left ventricular function in these patients. The present study aimed to quantify the acute changes in left ventricular function during the procedure by using myocardial tissue Doppler imaging and transthoracic cardiac output measurements.

DESIGN

Prospective observational study.

SETTING

Tertiary care university hospital.

PARTICIPANTS

40 patients with severe aortic stenosis scheduled for transcatheter aortic valve implantation.

INTERVENTIONS

Transesophageal 4-chamber and 2-chamber echocardiograms were performed immediately before and ~15 minutes after valve implantation. Longitudinal myocardial peak systolic velocity was obtained by tissue Doppler imaging from 8 basal segments and averaged. Cardiac output was measured by the lithium dilution method, and systemic vascular resistance index and stroke volume were calculated.

MEASUREMENTS AND MAIN RESULTS

Longitudinal myocardial peak systolic velocity improved immediately after valve implantation, from -2.3±0.8 to -3.0±1.1 cm/sec (p<0.001); this represented an average increase of 31%±33%. Cardiac output increased from 3.2±0.8 L/min to 3.6±0.9 L/min (15%±33%; p = 0.04). This was due to increased heart rate (59±9 beats/min to 72±12 beats/min; p<0.001) and not to an improved stroke volume. Systemic vascular resistance index was reduced from 2,937±984 dynes*sec/cm(5)/m(2) to 2,436±730 dynes*sec/cm(5)/m(2) (p = 0.003).

CONCLUSION

Intraoperative echocardiography tissue Doppler imaging detected immediate improvement in left ventricular long-axis motion after transcatheter aortic valve implantation. The method provided detailed information not obtainable by routine hemodynamic monitoring.

Cardiac critical care after transcatheter aortic valve replacement

Transcatheter aortic valve replacement (TAVR) is a new therapy for severe aortic stenosis now available in the United States. Initial patients eligible for TAVR are defined by high operative risk, with advanced age and multiple comorbidities. Following TAVR, patients experience acute hemodynamic changes and several possible complications, including hypotension, vascular injury, anemia, stroke, new-onset atrial fibrillation, conduction disturbances and kidney injury, requiring an acute phase of intensive care. Alongside improvements in TAVR technology and technique, improvements in care after TAVR may contribute to improved outcomes. This review presents an approach to post-TAVR critical care and identifies directions for future research.

Effect of Transcatheter Aortic Valve Replacement on the Mitral Valve Apparatus and Mitral Regurgitation

Background—

The effect of transcatheter aortic valve replacement (TAVR) on the mitral valve apparatus and factors influencing the reduction of mitral regurgitation with or without mitral leaflet tethering after TAVR are poorly understood. The present 3-dimensional (3D) transesophageal echocardiography study aimed to elucidate early changes further in the structure and function of the mitral valve apparatus after TAVR.

Methods and Results—

We analyzed 90 patients (nontenting group, 56 patients and tenting group, 34 patients) who underwent TAVR using the Edwards SAPIEN and had intraprocedural 3D transesophageal echocardiography evaluation of the mitral valve. Of all patients, mitral regurgitation improved in 54%, remained the same in 38%, and worsened in 8% 1 day after TAVR. There were no statistically significant differences in mitral annular 3D parameters before and after TAVR in both groups. In the tenting group, tenting area ( P <0.01) and tenting height ( P <0.01) were decreased, and coaptation length was increased ( P <0.05) after TAVR. In a multivariable analysis, the predictors of improved mitral regurgitation were the decrease of tenting area (odds ratio, 8.15; 95% confidence interval, 1.31–50.7; P <0.05) and the decrease of valvuloarterial impedance (odds ratio, 7.57; 95% confidence interval, 1.15–49.9; P <0.05) in the tenting group and the decrease of valvuloarterial impedance (odds ratio, 6.96; 95% confidence interval, 1.24–39.2; P <0.05) in the nontenting group.

Conclusions—

Mitral leaflet tethering was improved immediately by TAVR in patients with mitral leaflet tenting regardless of mitral annular geometry. Acute improvement in mitral regurgitation after TAVR is predominantly related to global left ventricular hemodynamics and mitral leaflet tethering change.

Left ventricular global systolic longitudinal deformation and prognosis 1 year after femoral and apical transcatheter aortic valve implantation

BACKGROUND

Aortic valve replacement is the recommended therapy for patients with severe aortic stenosis who have symptoms or decreased left ventricular (LV) function. Transcatheter aortic valve implantation (TAVI) is a treatment alternative in surgically high-risk or inoperable patients with severe aortic stenosis. The objective of this study was to analyze LV function assessed by global LV longitudinal systolic strain (GLS) and relation to prognosis in patients with severe aortic stenosis treated with femoral or apical TAVI.

METHODS

Two-dimensional echocardiography was performed before and 1 year after TAVI. Ejection fraction (EF) was retrospectively measured using the biplane Simpson's method, and GLS was obtained as an average of 16 segments in the three standard apical views by speckle-tracking. GE Vivid 7 and Vivid 9 machines were used for echocardiography, and speckle-tracking analysis was performed using EchoPAC PC '08 version 7.0.1.

RESULTS

The total population consisted of 100 TAVI patients. Eighty-one patients survived to 1-year follow-up, with a mean age of 81 ± 7 years (range, 64-93 years) and a mean European System for Cardiac Operative Risk Evaluation score of 9.6 ± 2.7. Nineteen patients died before 1-year follow-up (12 women), with a mean age of 82 ± 7 years (range, 66-92 years) and a mean European System for Cardiac Operative Risk Evaluation score of 10.5 ± 2.8. No differences were found between the 19 patients who died before follow-up and the 81 patients who survived to 1-year follow-up. GLS was increased significantly 1 year after TAVI. In 34 patients with EFs > 50%, GLS increased from -15.3 ± 3.4 to -17.1 ± 3.6 (P = .04). In these patients, the mean EF increased numerically from 57.9 ± 5.3% to 60 ± 7.7% (P = .19). In 74 patients with EFs ≤ 50%, mean GLS and EF improved significantly from -10 ± 2.8 to -13.8 ± 3.8 (P < .0001) and 39 ± 9.4% to 52 ± 12.5% (P < .0001), respectively. The 1-year gain in EF was the same after femoral TAVI (9.7 ± 10.1%) and after apical TAVI (8 ± 10.8%) (P = .52). Furthermore, GLS did not differ significantly after femoral and apical TAVI (-3.8 ± 3.3 and -2.6 ± 3.7, respectively, P = .21). There was no difference in causes of death according to approach. In the total population (n = 100), 35 deaths occurred, 19 before 1-year follow-up and 16 afterward. The median follow-up time was 30 months. Twenty-five patients (71%) died from cardiac causes. Overall 1-year mortality was 19%, and overall 2-year mortality was 28%. In the patients who died, the median survival time in the apical group was 28.5 ± 15.4 months, compared with 31.6 ± 19 months in the femoral group (P = .47). There was no impact on prognosis according to high (≥47.5%) versus low (<47.5%) baseline EF or high (≥11.95%) versus low (<11.95%) baseline GLS. However, the magnitude of changes in GLS seemed to have a prognostic impact.

CONCLUSIONS

LV EF and longitudinal systolic deformation were improved in TAVI independent of technical approach using the Edwards SAPIEN valve prosthesis during 1-year follow-up. The mortality rate was comparable between technical approaches and independent of baseline LV function. However, patients with the greatest improvement in LV systolic longitudinal deformation after TAVI had a lower mortality rate.