Effect of transcatheter aortic valve replacement on left atrial function

Left-atrial volume reduction reflects improvement of cardiac sympathetic nervous function in patients with severe aortic stenosis after transcatheter aortic valve replacement

Trans-catheter aortic valve replacement (TAVR) is an excellent alternative intervention for surgical aortic valve replacement. Cardiac sympathetic nervous (CSN) function and left atrial (LA) volume are both important prognostic factors in patients with aortic stenosis (AS) after TAVR. The relationship between the two clinical factors is unknown, however. This retrospective observational study aimed to assess the correlation between CSN function and LA volume in 48 symptomatic patients with severe AS (median age: 85 years, IQR 82-88 years; 81% female) before and after TAVR. CSN function was assessed by performing ¹²³I-metaiodobenzylguanidine (MIBG) scintigraphy before and 6 months after TAVR, and the delayed heart-to-mediastinum ratio (dHMR) and washout rate (WR) were calculated. We also performed transthoracic echocardiography near the same time. TAVR improved the dHMR, WR, and LA volume index (LAVI) (dHMR: median 2.89 [IQR 2.62-3.23] vs. 2.98 [2.49-3.25], p = 0.0182; WR: 28% [24-38] vs. 23% [16-32], p < 0.0001; LAVI: 47.7 mL/m² [37.8-56.3] vs. 41.2 mL/m² [33.7-56.1], p = 0.0024). In multiple linear regression analysis, the percentage change in LAVI from baseline to post-TAVR (∆LAVI%) was an independent predictor of change in dHMR from baseline to post-TAVR (β =  - 0.35, p = 0.0110). In conclusion, LA volume reduction reflected CSN functional improvement after TAVR. In patients with TAVR, ∆LAVI% might be a valuable parameter for evaluating CSN functional recovery.

Utility of Functional and Volumetric Left Atrial Parameters Derived From Preprocedural Cardiac CTA in Predicting Mortality After Transcatheter Aortic Valve Replacement

Background: Cardiac CTA is required for preprocedural workup before transcatheter aortic valve replacement (TAVR) and can be used to assess functional parameters of the left atrium (LA). Objective: We aimed to evaluate the utility of functional and volumetric LA parameters derived from cardiac CTA to predict mortality in patients with severe aortic stenosis (AS) undergoing TAVR. Methods: This retrospective study included 175 patients with severe AS (median age 79 years; 92 male, 83 female) who underwent cardiac CTA for clinical pre-TAVR assessment. A postdoctoral research fellow calculated maximum and minimum LA volumes using biplane area-length measurements; the values were indexed to body surface area (LAVImax and LAVImin, respectively). LA emptying fraction (LAEF) was automatically calculated. All-cause mortality within a 24-month follow-up period post-TAVR was recorded. To identify parameters predictive of mortality, Cox regression was performed, and results were summarized by hazard ratio (HR) and 95% CI. Harrell's c-index was used to assess model performance. A radiology resident repeated the measurements in a random sample of 20% (n=35) of cases, and interobserver agreement was computed using the intraclass correlation coefficient (ICC). Results: Thirty-eight deaths (22%) were recorded within a median follow-up of 21 months. LAVImax (HR 1.02 [1.01-1.04]; p=.005), LAVImin (HR 1.02 [1.01-1.04]; p<.001), and LAEF (HR 0.97 [0.95-0.99]; p=.002) were predictive of mortality in univariable analysis. After adjusting for clinical parameters, only LAEF (HR 0.97 [0.94-0.99]; p=.02) independently predicted mortality. The c-index of the Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) significantly increased from 0.64 to 0.68, 0.69, and 0.70 when incorporating into the model LAVImax, LAVImin, and LAEF, respectively. ICC for maximum and minimum LA volumes and LAEF ranged from 0.94 to 0.99. Conclusion: LAEF derived from preprocedural cardiac CTA independently predicts mortality in patients with severe AS undergoing TAVR. Clinical impact: Cardiac CTA-derived LA function, evaluated during pre-TAVR workup, can be used to assess preprocedural risk and may improve risk stratification in post-TAVR surveillance.

The Prognostic Value of Left Atrial Global Longitudinal Strain and Left Atrial Phasic Volumes in Patients Undergoing Transcatheter Valve Implantation for Severe Aortic Stenosis

INTRODUCTION

The changes and the prognostic implications of left atrial (LA) volumes (LAV), LA function, and vascular load in patients undergoing transcatheter aortic valve implantation (TAVI) for severe aortic stenosis (AS) are less known.

METHODS

We enrolled 150 symptomatic patients (mean age 82 ± 8 years, 58% female, and pre-TAVI aortic valve area 0.40 ± 0.19 cm/m2) with severe AS who underwent 2D transthoracic echocardiography and 2D speckle tracking echocardiography at average 21 ± 35 days before and 171 ± 217 days after TAVI. The end point was a composite of new onset of atrial fibrillation, hospitalization for heart failure and all-cause death (major adverse cardiac events [MACE]).

RESULTS

After TAVI, indexed maximal LA volume and minimum volume of the LA decreased by 2.1 ± 10 mL/m2 and 1.6 ± 7 mL/m2 (p = 0.032 and p = 0.011, respectively), LA function index increased by 6.8 ± 11 units (p < 0.001), and LA stiffness decreased by 0.38 ± 2.0 (p = 0.05). No other changes in the LA phasic volumes, emptying fractions, and vascular load were noted. Post-TAVI, both left atrial and ventricular global peak longitudinal strain improved by about 6% (p = 0.01 and 0.02, respectively). MACE was reached by 37 (25%) patients after a median follow-up period of 172 days (interquartile range, 20-727). In multivariable models, MACE was associated with both pre- and post-TAVI LA global peak longitudinal strain (hazard ratio [HR] 0.75, CI 0.59-0.97; and HR 0.77, CI 0.60-1.00, per 5 percentage point units, respectively), pre-TAVI LV global endocardial longitudinal strain (HR 1.37, CI 1.02-1.83 per 5 percentage point units), and with most of the LA phasic volumes.

CONCLUSION

Within 6 months after TAVI, there is reverse LA remodeling and an improvement in LA reservoir function. Pre- and post-TAVI indices of LA function and volume remain independently associated with MACE. Larger studies enrolling a greater diversity of patients may provide sufficient evidence for the utilization of these imaging biomarkers in clinical practice.

Optimal antithrombotic therapy after transcatheter aortic valve replacement in patients with atrial fibrillation

Atrial fibrillation (AF) is prevalent in patients with aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR). Depending on the timing of AF detection, it is usually categorized as pre-existing AF or new-onset AF. Antiplatelet therapy, rather than a vitamin K antagonist, may be considered as the primary treatment for patients without an indication for oral anticoagulants who undergo TAVR. However, the optimal postprocedural antithrombotic regimen for patients with AF undergoing TAVR remains unknown. In this review, we briefly introduce the management strategies of antithrombotic therapy and list the evidence from related studies to elucidate the optimal antithrombotic management for patients with AF undergoing TAVR.

Higher preoperative left atrial volume index predicts lack of mitral regurgitation improvement after transcatheter aortic valve replacement

BACKGROUND

Moderate-to-severe mitral regurgitation is present in 20-35% of patients undergoing transcatheter aortic valve replacement (TAVR) and the current literature lacks simple echocardiographic parameters, which can predict post-TAVR changes in mitral regurgitation. The aim of this study is to investigate the echocardiographic predictors of improvement or worsening of mitral regurgitation in patients undergoing TAVR with moderate-to-severe mitral regurgitation.

METHODS

This retrospective study included 113 patients who underwent TAVR with preoperative mitral regurgitation grade at least 2. Patients with concomitant coronary artery disease requiring treatment were excluded. Mitral regurgitation was related to the annular dilatation or tethering mechanism in all patients. Preoperative and postoperative echocardiographies were compared in terms of mitral regurgitation and other commonly measured parameters.

RESULTS

After TAVR, a reduction in mitral regurgitation was observed in 62.8% of cases. On the basis of the difference between postoperative and preoperative echocardiograms, 71 patients had improved mitral regurgitation, whereas 42 patients had stable or worsened mitral regurgitation. After analyzing preoperative echocardiographic parameters with regard to this group difference, left atrial volume index (LAVI) was the only variable that was different between groups (33.4 ± 4.8 ml/m in improved mitral regurgitation vs. 39.8 ± 3.0 ml/m in not improved mitral regurgitation, P < 0.001). In a multivariable logistic regression model, a LAVI increase was associated with lack of an acute reduction in mitral regurgitation (odds ratio = 1.41, P < 0.001) after adjustment for age and preoperative serum creatinine.

CONCLUSION

Higher preoperative LAVI is a determinant predictor of lack of an acute reduction in mitral regurgitation after TAVR, and LAVI could be used as a stratifying tool to tailor the treatment strategy and the timing of the procedures. However, validation of these results and long-term outcomes are warranted to support those conclusions.

New Onset Atrial Fibrillation Following Transcatheter and Surgical Aortic Valve Replacement: A Systematic Review and Meta-Analysis

BACKGROUND

New-onset atrial fibrillation (NOAF) is a well-recognised, although variably reported complication following surgical aortic valve replacement (SAVR). Rates of NOAF following transcatheter aortic valve implantation (TAVI) seem to be notably less than SAVR, even though this population is typically older and of higher risk. The aim of this study was to determine the prevalence of NOAF in both these populations and associated postoperative outcomes.

METHODS

We conducted a systematic review and meta-analysis of studies reporting rates of NOAF post SAVR or TAVI, along with early postoperative outcomes. Twenty-five (25) studies with a total of 13,010 patients were included in the final analysis.

RESULTS

The prevalence of NOAF post SAVR was 0.4 (95% CI 0.36-0.44) and post TAVI 0.15 (95% CI 0.11-0.18). NOAF was associated with an increased risk of postoperative cerebrovascular accident (CVA) for SAVR and TAVI (RR 1.44 95% CI 1.01-2.06 and RR 2.24 95% CI 1.46-3.45 respectively). NOAF was associated with increased mortality in the TAVI group (RR 3.02 95% CI 1.55-5.9) but not the SAVR group (RR 1.00, 95% CI 0.54-1.84). Hospital length of stay was increased for both TAVI and SAVR patients with NOAF (MD 2.54 days, 95% CI 2.0-3.00) and (MD 1.64 days, 95% CI 0.04-3.24 respectively).

CONCLUSIONS

The prevalence of NOAF is significantly less following TAVI, as compared to SAVR. While NOAF is associated with increased risk of postoperative stroke for both groups, for TAVI alone NOAF confers increased risk of early mortality.

Impact of Pre-Existing and New-Onset Atrial Fibrillation on Outcomes After Transcatheter Aortic Valve Replacement

OBJECTIVES

This study sought to evaluate impact of new-onset and pre-existing atrial fibrillation (AF) on transcatheter aortic valve replacement (TAVR) long-term outcomes compared with patients without AF.

BACKGROUND

Pre-existing and new-onset AF in patients undergoing TAVR are associated with poor outcomes.

METHODS

The study identified 72,660 patients ≥65 years of age who underwent nonapical TAVR between 2014 and 2016 using Medicare inpatient claims. History of AF was defined by diagnoses on claims during the 3 years preceding the TAVR, and new-onset AF was defined as occurrence of AF during the TAVR admission or within 30 days after TAVR in a patient without prior history of AF. Outcomes included all-cause mortality, and readmission for bleeding, stroke, and heart failure (HF).

RESULTS

Overall, 40.7% had pre-existing AF (n = 29,563) and 6.8% experienced new-onset AF (n = 2,948) after TAVR. Mean age was 81.3, 82.4, and 83.8 years in patients with no AF, pre-existing, and new-onset AF, respectively. Pre-existing AF patients had the highest burden of comorbidities. After follow-up of 73,732 person-years, mortality was higher with new-onset AF compared with pre-existing and no AF (29.7, 22.6, and 12.8 per 100 person-years, respectively; p < 0.001). After adjusting for patient characteristics and hospital TAVR volume, new-onset AF remained associated with higher mortality compared with no AF (adjusted hazard ratio: 2.068, 95% confidence interval [CI]: 1.92 to 2.20; p < 0.01) and pre-existing AF (adjusted hazard ratio: 1.35; 95% CI: 1.26 to 1.45; p < 0.01). In competing risk analysis, new-onset AF was associated with higher risk of bleeding (subdistribution hazard ratio [sHR]: 1.66; 95% CI: 1.48 to 1.86; p < 0.01), stroke (sHR: 1.92; 95% CI: 1.63 to 2.26; p < 0.01), and HF (sHR: 1.98; 95% CI: 1.81 to 2.16; p < 0.01) compared with pre-existing AF.

CONCLUSIONS

In patients undergoing TAVR, new-onset AF is associated with increased risk of mortality and bleeding, stroke, and HF hospitalizations compared with pre-existing AF or no AF.