Changes in myocardial deformation after transcatheter and surgical aortic valve replacement

Speckle tracking echocardiography (STE) has emerged as a novel angle‐independent modality in assessing myocardial velocity, deformation, and strain. Its role in assessing change before and after aortic valve replacement in patients with aortic stenosis (AS) has recently generated interest. This review summarizes the practical utility and clinical implications of myocardial deformation by STE after surgical or transcatheter aortic valve replacement (TAVR). Overall, atrial strain and ventricular strain as measured by STE improve after surgical and transcatheter aortic intervention in short‐ and long‐term follow‐up with evidence of a more pronounced acute improvement in patients who undergo TAVR. STE assessment of strain, particularly global longitudinal strain, can detect subtle changes in myocardial systolic function prior to conventional variables such as left ventricular ejection fraction and is clinically useful in predicting mortality and symptom development in patients with AS. This underscores the emerging role of STE in monitoring post‐procedural improvements in cardiac function as well as the potential value in guiding optimal timing of AS intervention.     

Transcatheter aortic valve replacement: The year in review 2016

Transcatheter aortic valve replacement (TAVR) continued to make major strides in 2016, simultaneously expanding its application to lower risk patients as well as more technically challenging subsets of patients with aortic stenosis (AS). The two major accomplishments this year were the establishment of TAVR as the preferred treatment strategy over surgical aortic valve replacement (SAVR) in intermediate risk patients, and initial signals that TAVR and SAVR may be clinically equivalent in low‐risk populations. Meanwhile, there is continued expansion of TAVR to challenging clinical subsets (bicuspid aortic valve [BAV], patients with concomitant advanced coronary artery disease [CAD], and failed surgical bioprostheses), and encouraging initial experiences with newer transcatheter heart valve systems. This paper summarizes the major research studies published on TAVR in 2016.

     

Long-term outlook for transcatheter aortic valve replacement

Transcatheter aortic valve replacement (TAVR) revolutionized the treatment of severe symptomatic aortic stenosis (AS). TAVR is increasingly offered for lower-risk patients. The role and place of TAVR in the future treatment of AS is not clear yet. In this review, we discuss the long-term outlook for TAVR, its challenges and its relationship to conventional surgical aortic valve replacement.     

The impact of mitral stenosis on outcomes of aortic valve stenosis patient undergoing surgical aortic valve replacement or transcatheter aortic valve replacement

Background

The concomitant presence of mitral stenosis (MS) in the setting of symptomatic aortic stenosis represent a clinical challenge. Little is known regarding the outcome of mitral stenosis (MS) patients undergoing transcatheter aortic valve replacement (TAVR) or surgical aortic valve replacement (SAVR). Therefore, we sought to study the outcome of MS patients undergoing aortic valve replacement (AVR).

Method

Using weighted data from the National Inpatient Sample (NIS) database between 2011 and 2014, we identified patients who were diagnosed with MS. Patients who had undergone TAVR as a primary procedure were identified and compared to patients who had SAVR. Univariate and multivariate logistic regression analysis were performed for the outcomes of in‐hospital mortality, length of stay (LOS), blood transfusion, postprocedural hemorrhage, vascular, cardiac and respiratory complications, permanent pacemaker placement (PPM), postprocedural stroke, acute kidney injury (AKI), and discharge to an outside facility.

Results

A total of 4524 patients were diagnosed with MS, of which 552 (12.2%) had TAVR and 3972 (87.8%) had SAVR. TAVR patients were older (79.9 vs 70.0) with more females (67.4% vs 60.0%) and African American patients (7.7% vs 7.1%) (P < 0.001). In addition, the TAVR group had more comorbidities compared to SAVR in term of coronary artery disease (CAD), congestive heart failure (CHF), chronic lung disease, hypertension (HTN), chronic kidney disease (CKD), and peripheral vascular disease (PVD) (P < 0.001 for all). Using Multivariate logistic regression, and after adjusting for potential risk factors, TAVR patients had lower in‐hospital mortality (7.9% vs 8.1% adjusted Odds Ratio [aOR], 0.615; 95% confidence interval [CI], 0.392–0.964, P = 0.034), shorter LOS. Also, TAVR patients had lower rates of cardiac and respiratory complications, PPM, AKI, and discharge to an outside facility compared with the SAVR group.

Conclusion

In patients with severe aortic stenosis and concomitant mitral stenosis, TAVR is a safe and attractive option for patients undergoing AVR with less complications compared with SAVR.

     

Left ventricular remodeling early after aortic valve replacement: differential effects on diastolic function in aortic valve stenosis and aortic regurgitation

OBJECTIVES: The aim of this study was to evaluate the effect of aortic valve replacement (AVR) on left ventricular (LV) function and LV remodeling, comparing patients with aortic valve stenosis to patients with aortic regurgitation. BACKGROUND: Aortic valve disease is associated with eccentric or concentric LV hypertrophy and changes in LV function. The relationship between LV geometry and LV function and the effect of LV remodeling after AVR on diastolic filling, in patients with aortic valve stenosis compared with aortic regurgitation, are largely unknown.Nineteen patients with aortic valve disease (12 aortic valve stenosis, 7 aortic regurgitation) were studied using magnetic resonance imaging to assess LV geometry and LV function before and 9 +/- 3 months after AVR. Ten age-matched healthy males served as control subjects. RESULTS: Before AVR, the ratio between left ventricular mass index (LVMI) and left ventricular end-diastolic volume index (LVEDVI) was only increased in patients with aortic valve stenosis (1.37 +/- 0.16 g/ml) compared with control subjects (0.93 +/- 0.08 g/ml, p < 0.05). After AVR, LVMI/LVEDVI decreased significantly in aortic valve stenosis (to 1.15 +/- 0.14 g/ml, p < 0.0001), but increased significantly in aortic regurgitation (1.02 +/- 0.20 g/ml to 1.44 +/- 0.27 g/ml, p < 0.0001). Before AVR, diastolic filling was impaired in both aortic valve stenosis and aortic regurgitation. Early after AVR, diastolic filling improved in patients with aortic valve stenosis, whereas patients with aortic regurgitation showed a deterioration in diastolic filling. CONCLUSIONS: Early after AVR, patients with aortic valve stenosis show a decrease in both LVMI and LVMI/LVEDVI and an improvement in diastolic filling, whereas in patients with aortic regurgitation, LVMI decreases less rapidly than LVEDVI, causing concentric remodeling of the LV, most likely explaining the observed deterioration of diastolic filling in these patients.     

The bicuspid aortic valve: Still a toothy problem

• Transcatheter aortic valve replacement (TAVR) is an acceptable treatment alternative to surgical aortic valve replacement in selected patients with a bicuspid aortic valve.
• TAVR appears to have acceptable mid‐term outcomes in patients with bicuspid aortic stenosis.
• A large‐scale, randomized, clinical trial is necessary to better define the role of TAVR for patients with bicuspid aortic stenosis.

     

Mixed aortic valve disease treated with transcatheter aortic valve replacement in a high risk patient presenting with acute decompensated heart failure

Mixed aortic valve disease refers to the combination of aortic regurgitation (AR) and aortic stenosis (AS). Commonly etiologies include a bicuspid aortic valve, rheumatic heart disease, and endocarditis superimposed upon a stenotic aortic valve. Treatment depends upon the severity of disease, the presence of symptoms and the size and function of the left ventricle. We present a case of a young patient that presented with new onset acute decompensated heart failure with mixed aortic valve disease that was successful treated with transcatheter aortic valve replacement (TAVR). Invasive hemodynamics at baseline and following TAVR provide an insight into the characteristic features of mixed aortic valve disease. TAVR represents a new treatment option for critically ill patients deemed high risk or nonoperable for surgical aortic valve replacement.     

Transcatheter aortic valve replacement in patients with severe aortic stenosis and heart failure

Severe aortic stenosis (AS) and heart failure (HF) represent an important and high-risk group of patients who are often referred for transcatheter aortic valve replacement (TAVR) due to high risk for surgical intervention. Thus far, randomized controlled trials have shown comparable outcomes between TAVR and surgical aortic valve replacement in patients with severe AS and heart failure with reduced ejection fraction. In the current review, we will discuss (1) the pathophysiology of HF in patients with severe AS, (2) role of imaging modalities in management, (3) role of biomarkers of HF on prognosis, (4) impact of other valvular heart diseases, (5) evidence from the contemporary trials on the role of TAVR in patients with severe AS and HF, and (6) future directions and research.     

Immediate effect of aortic valve replacement for aortic stenosis on left ventricular diastolic chamber stiffness.

Diastolic dysfunction is common after coronary artery bypass surgery, and we hypothesized that left ventricular (LV) hypertrophy associated with aortic stenosis may lead to worsening LV diastolic function after aortic valve replacement for aortic stenosis. Transesophageal echocardiographic LV images and simultaneous pulmonary arterial wedge pressures were used to define the LV diastolic pressure cross-sectional area relation before and immediately after aortic valve replacement for aortic stenosis in 14 patients. In all patients, LV diastolic chamber stiffness increased, as evidenced by a leftward shift in the LV diastolic pressure cross-sectional area relation. At comparable LV filling (pulmonary arterial wedge) pressures the mean LV end-diastolic cross-sectional area preoperatively was 17.9 +/- 1.7 cm2, but decreased by 32% after aortic valve replacement to 12.1 +/- 1.2 cm2 (p = 0.0001). In conclusion, after aortic valve replacement, diastolic chamber stiffness increased in all patients.     

Tissue Doppler imaging in patients with moderate to severe aortic valve stenosis: clinical usefulness and diagnostic accuracy

Background

Mitral annular velocities derived from tissue Doppler imaging (TDI) provide information about left ventricular (LV) long-axis function and allow for the assessment of LV filling pressures in selected subsets of patients. It was the aim of this study to assess the usefulness of TDI in patients with moderate to severe aortic valve stenosis (AS).

Methods

Twenty-three patients with moderate to severe AS (mean aortic valve area 0.8 ± 0.4 cm²), in whom coronary artery disease had been ruled out, and 36 asymptomatic age-matched control subjects underwent assessment of ejection fraction, fractional shortening, and mitral inflow (E, A, E/A ratio). TDI velocities (S', E', A') were derived from the septal mitral annulus. In patients with AS, LV pressure before atrial contraction (LV pre-A pressure), LV end-diastolic pressure, and cardiac index were measured during cardiac catheterization.

Results

In patients with AS, systolic (S') and early diastolic mitral annular velocities (E') were significantly reduced in comparison to control subjects (systolic, 5.5 ± 1.2 vs 8.3 ± 1.3 cm/s; early diastolic, 5.6 ± 1.6 vs 10.2 ± 3.0 cm/s, P < .001 for both comparisons), but ejection fraction, fractional shortening, and cardiac index were normal. In patients with AS, LV pre-A pressures (14 ± 4 mm Hg) and end-diastolic pressures were high (19 ± 7 mm Hg). In such patients, the mitral E/E' ratio was significantly related to LV pre-A pressure (r = 0.75, P < .001) and to LV end-diastolic pressure (r = 0.78, P < .001). In patients with AS, an E/E' ratio ≥13 identified an LV end-diastolic pressure >15 mm Hg, with a sensitivity of 93% and a specificity of 88%.

Conclusions

In patients with moderate to severe AS, TDI allows for a reliable, noninvasive estimation of filling pressures. In such patients, systolic long-axis function is impaired even in the presence of normal ejection fraction and cardiac index. Thus, TDI integrates information about systolic and diastolic performance and may be a useful addition in the echocardiographic workup and care of patients with AS.     

Frequency, determinants and outcome of pulmonary hypertension in patients with aortic valve stenosis

IntroductionThe frequency, causes and prognostic implications of pulmonary hypertension (PHT) in patients with severe aortic stenosis (AS) are not well defined. The objectives of this study were to determine the frequency of PHT [pulmonary artery systolic pressure (PASP) > 50 mm Hg] in patients with severe AS, identify the factors associated with PHT and assess the relationship between PHT and clinical outcome.MethodsPatients with severe AS (aortic valve area ≤ 1.0 cm²) and an echocardiographic estimate of PASP were identified by using the institutional echocardiography laboratory database. Patients with atrial fibrillation, mitral valve stenosis or a mitral prosthesis were excluded from analysis. The associations between clinical and echocardiographic parameters and PHT and the relationship between PHT and outcome were examined.ResultsDuring the study period, 216 patients fulfilled the inclusion criteria (age: 75 ± 11 years; 43% men), and PHT was present in 64 patients (29.6%). By multivariate analysis, reduced left ventricular (LV) systolic function (LV ejection fraction ≤ 45% and lower stroke volume) and impaired LV diastolic function (mitral inflow E/A ratio ≥ 1.5 and greater left atrium size) were independent predictors of PHT. Mortality was higher among patients with PHT managed medically (adjusted hazard ratio, 1.87; 95% confidence interval, 1.06–3.30; P = 0.011), whereas patients with PHT who underwent aortic valve replacement had an excellent outcome.ConclusionsPHT is common in patients with AS and is related to the severity of LV systolic and diastolic dysfunction. PHT is associated with poorer outcome in medically treated patients.     

Successful transfemoral aortic valve replacement in a bicuspid aortic stenotic valve: Requirements for a safe implant

Although transcatheter aortic valve replacement (TAVR) has been accepted as an attractive alternative for high‐risk patients with severe symptomatic aortic stenosis (AS), patients with congenital bicuspid AS has been typically disqualified for this indication due to an implied risk of device dislocation, distortion, or device malfunctioning. Nonetheless, bicuspid AS is not uncommon and frequently missed by transthoracic echocardiography. We reported an interesting case of a high‐risk patient with severe symptomatic bicuspid AS who underwent successful TAVR and discussed the anatomic requirements for a safe implant in patients with bicuspid AS considered candidates for TAVR. © 2013 Wiley Periodicals, Inc.     

Transcatheter aortic valve replacement: Protect the kidneys to protect the patient

• Transcatheter aortic valve replacement (TAVR) seems superior to surgical aortic valve replacement (SAVR) for intermediate‐term outcomes in patients with aortic stenosis and moderate to severe chronic kidney disease (CKD).
• Intermediate‐term mortality and the major adverse cardiac and renal event increase if the renal function worsens soon after TAVR or SAVR.
• Patient's demographic profile, comorbid conditions, and procedural characteristics influence the clinical outcomes emphasizing the need for careful risk assessment in deciding TAVR versus SAVR in CKD patient.

     

Balloon aortic valvuloplasty to improve candidacy of patients evaluated for transcatheter aortic valve replacement

Objectives

Evaluate the role of balloon aortic valvuloplasty (BAV) in improving candidacy of patients for transcatheter aortic valve replacement (TAVR).

Background

Patients who are not candidates for TAVR may undergo BAV to improve functional and clinical status.

Methods

117 inoperable or high‐risk patients with critical aortic stenosis underwent BAV as a bridge‐to‐decision for TAVR. Frailty measures including gait speed, serum albumin, hand grip, activities of daily living (ADL); and NYHA functional class before and after BAV were compared.

Results

Mean age was 81.6 ± 8.5 years and the mean Society of Thoracic Surgeons predicted risk of mortality was 9.57 ± 5.51, with 19/117 (16.2%) patients non‐ambulatory. There was no significant change in mean GS post‐BAV, but all non‐ambulatory patients completed GS testing at follow‐up. Albumin and hand grip did not change after BAV, but there was a significant improvement in mean ADL score (4.85 ± 1.41 baseline to 5.20 ± 1.17, P = 0.021). The number of patients with Class IV congestive heart failure (CHF) was significantly lower post BAV (71/117 [60.7%] baseline versus 18/117 [15.4%], P = 0.008). 78/117 (66.7%) of patients were referred to definitive valve therapy after BAV.

Conclusions

When evaluating frailty measures post BAV, we saw no significant improvement in mean GS, however, we observed a significant improvement in non‐ambulatory patients and ADL scores. We also describe improved Class IV CHF symptoms. With this improved health status, the majority of patients underwent subsequent valve therapy, demonstrating that BAV may improve candidacy of patients for TAVR.     

Pressure-volume loops in patients with aortic stenosis

BACKGROUND AND AIM OF THE STUDY: Preoperative left ventricular (LV) function is the strongest predictor of outcome after valve replacement for aortic stenosis (AS). Although pressure-volume analysis with the conductance catheter technique can provide detailed information on LV systolic and diastolic function, this technique has not yet been used in AS patients. The present study examined the potential use of LV function measurements using pressure-volume analysis with a conductance catheter during surgery for AS. METHODS: In six patients with severe symptomatic AS, a conductance catheter was placed under transesophageal echocardiographic guidance in the left ventricle via the right superior pulmonary vein. RESULTS: The procedure was successful in all patients and lengthened the duration of surgery by <30 min, but with no increase in bypass or aortic cross-clamp times. Pressure-volume analysis showed that systolic function was normal in all patients (ejection fraction 42-59%, end-systolic elastance 1.6-4.5 mmHg/ml), while diastolic dysfunction was found in all patients (Tau 32-96 ms, LV end-diastolic pressure 7-42 mmHg, atrial kick 25-60%). After valve replacement, systolic function improved, but diastolic function did not. CONCLUSION: The conductance catheter placed via the pulmonary vein can determine LV systolic and diastolic dysfunction in detail in an individual patient with AS before and after valve replacement. The technique may be used to extend diagnostic data from less-invasive modalities and to determine prognosis in the individual patient.     

Comparing outcomes after transcatheter aortic valve replacement in patients with stenotic bicuspid and tricuspid aortic valve: A systematic review and meta‐analysis

Background

Transcatheter aortic valve replacement (TAVR) has become an alternative treatment to surgery in patients with severe aortic stenosis. However, patients with bicuspid aortic stenosis (BAV) are usually excluded from major TAVR studies. The aim of this study is to reexamine current evidence of TAVR in patients with severe aortic stenosis and BAV compared with tricuspid aortic valve (TAV).

Hypothesis

There might be differences in outcomes post TAVR between patients with BAV comparing to TAV.

Method

Databases were systematically searched for relevant articles featuring cohort studies that included patients with BAV and TAV who underwent TAVR studies, of which reported outcomes of interest included mortality and complications in both groups. Pooled effect size was calculated with a random‐effect model and weighted for the inverse of variance, to compare outcomes post‐TAVR between BAV and TAV.

Results

Nine studies were included in the meta‐analysis. There was no difference in 30‐day mortality rate in patients with BAV compared with TAV (OR: 1.27, 95% CI: 0.84–1.93, I² = 0). Patients with BAV were more likely to have a moderate to severe paravalvular leak (9 studies; OR: 1.42, 95% CI: 1.08–1.87, I² = 0) and conversion to surgery (5 studies; OR: 5.48, 95% CI: 1.74–17.27, I² = 0), and less likely to have device success compared with patients with TAV (5 studies; OR: 0.57, 95% CI: 0.40–0.81, I² = 0%).

Conclusions

There was no difference in mortality post‐TAVR in patients with BAV compared with TAV. Further randomized studies should be done in newer‐generation prostheses to assess this association.     

Diastolic stiffness and myocardial structure in aortic valve disease before and after valve replacement

Passive diastolic properties were determined in 10 control patients and 21 patients with aortic valve disease before and 17.5 months after successful valve replacement. Ten patients had severe aortic stenoses (AS), five had combined aortic valve lesions (AS + aortic insufficiency [AI]), and six patients had severe AI. Left ventricular endomyocardial biopsies were obtained before and after surgery in patients with AS, AS + AI, and AI. Simultaneous echocardiographic and high-fidelity pressure measurements were made in all patients, and left ventricular chamber stiffness was calculated from a viscoelastic pressure-circumference relationship and left ventricular myocardial stiffness from a viscoelastic stress-strain relationship. The constant of chamber stiffness, beta', was slightly although not significantly increased in patients with AS (0.27 before and 0.24 after surgery), but was normal in those with AS + AI (0.22 before and 0.17 after surgery) and slightly decreased in those with AI (0.18 before and 0.16 after surgery) when compared with in control subjects (0.21). The constant of myocardial stiffness beta was normal in patients with AS (13.2), AS + AI (11.5), and AI (11.7) before surgery compared with in the control group (12.5). beta increased, however, significantly in those with AS (25.2; p less than .02), but not in those with AS + AI (16.3; NS) and AI (12.8; NS) after surgery. Myocardial morphologic characteristics showed a significant decrease in muscle fiber diameter in patients with AS, AS + AI, and AI, as well as a significant increase in interstitial fibrosis from 15% to 26% (p less than .05) in those with AS and a slight increase from 15% to 22% (NS) in those with AS + AI and from 19% to 24% (NS) in those with AI. Left ventricular fibrous content (left ventricular muscle mass index multiplied by interstitial fibrosis) remained, however, unchanged in all three groups after aortic valve replacement. In conclusion, left ventricular chamber stiffness is increased in AS but decreased in AI, whereas LV myocardial stiffness is normal in patients with aortic valve disease before surgery. After surgery, left ventricular myocardial stiffness increased significantly in AS patients but remained unchanged in those with AI. Postoperative changes in myocardial structure were characterized by a decrease in muscle fiber diameter and a relative increase in interstitial fibrosis, whereas fibrous content remained unchanged. Thus, regression of myocardial hypertrophy in aortic valve disease is accompanied by an increase of myocardial stiffness in concentric hypertrophy that is not seen in eccentric hypertrophy.     

Relation of myocardial mechanics in severe aortic stenosis to left ventricular ejection fraction and response to aortic valve replacement

Decreased left ventricular (LV) longitudinal strain and increased circumferential LV strain have been demonstrated in patients with severe aortic stenosis (AS) and normal LV ejection fraction (LVEF). Biplane myocardial mechanics normalize after aortic valve replacement (AVR). This study objective was to examine LV mechanics before and soon after AVR in patients with AS and LV systolic dysfunction. Paired echocardiographic studies before and soon (7 ± 3 days) after AVR were analyzed in 64 patients with severe AS: 32 with normal LVEF (≥ 50%), 16 with mild to moderate LV dysfunction (LVEF <36% to 50%), and 16 with severe LV dysfunction (LVEF ≤ 35%). Longitudinal myocardial function was assessed from 3 apical views (average of 18 segments) and circumferential function was assessed at mid-LV and apical levels (average of 6 segments per view). Strain, strain rate, and mid-LV and apical rotations were measured using 2-dimensional velocity vector imaging. Before AVR (1) longitudinal strain was low in all patients and correlated with LVEF (ρ = 0.74, p <0.001), (2) mid-LV circumferential strain was supranormal in patients with normal LVEF and low in patients with low LVEF (ρ = 0.88, p <0.001), and (3) apical rotation was highest in patients with mild to moderate LV dysfunction. After AVR, LVEF increased in patients with LV dysfunction and myocardial mechanics partly normalized. In conclusion, compensatory mechanisms (high circumferential strain in patients with preserved LVEF and increased apical rotation in patients with mild to moderate LV dysfunction) were observed in patients with severe AS. Compensatory mechanics were lost in patients with severe LV dysfunction. AVR partly reversed these changes in patients with LV dysfunction.     

Bioprosthetic aortic valve leaflet disruption with high energy electrocautery to prevent coronary artery obstruction during valve‐in‐valve transcatheter aortic valve replacement

Transcatheter aortic valve replacement (TAVR) is well‐established for the treatment of bioprosthetic aortic valve stenosis (AS) in high surgical risk patients. Coronary artery obstruction from displacement of the bioprosthetic valve leaflets during valve‐in‐valve (VIV) TAVR is a rare, but potentially fatal, complication. Recently, the bioprosthetic aortic scallop intentional laceration to prevent iatrogenic coronary artery obstruction (BASILICA) procedure was developed as a method for disrupting bioprosthetic leaflets in patients undergoing VIV TAVR at high risk for coronary obstruction. This case describes a successful VIV TAVR utilizing a simplified concept of the BASILICA technique in a patient where the full procedure could not be completed.