Long-term survival after TAVI in low-flow, low-gradient aortic valve stenosis

BACKGROUND

In patients undergoing transcatheter aortic valve implantation (TAVI), the presence of a low-flow, low-gradient (LFLG) status has been associated with higher mortality at short-term follow-up.

AIMS

We aimed to evaluate long-term survival after TAVI in patients with classical (cLFLG) and paradoxical LFLG (pLFLG) aortic stenosis (AS) compared to high-gradient (HG)-AS.

METHODS

Patients undergoing TAVI at our centre with a hypothetical minimum 5-year follow-up were divided into 3 groups: (1) HG-AS (mean gradient [MG] >40 mmHg), (2) cLFLG-AS (MG <40 mmHg, ejection fraction [EF] <50%), and (3) pLFLG-AS (MG <40 mmHg, EF ≥50%). The primary endpoint of the study was all-cause mortality. Propensity score-weighted survival analysis was performed to adjust for possible baseline confounders.

RESULTS

A total of 574 subjects were included (73% HG-AS, 15% pLFLG-AS, 11% cLFLG-AS). The median survival time was 4.8 years, with a maximum of 12.3 years. Patients with cLFLG-AS presented the highest baseline cardiovascular risk. At unadjusted survival analysis, patients with cLFLG-AS showed the worst long-term prognosis, with a rapid decrease in survival within the first year, while pLFLG- and HG-AS patients presented similar survival rates (p=0.023). At weighted long-term analysis, cLFLG- and HG-AS had similar survival rates. Baseline EF was not related to long-term mortality, while patients with a post-TAVI left ventricular ejection fraction (LVEF) improvement >10% lived significantly longer (p=0.02).

CONCLUSIONS

Classical LFLG-AS patients had lower long-term survival rates as compared to pLFLG-AS and HG-AS patients. However, after adjustment for possible baseline confounders, a low-flow status per se did not have an impact on long-term mortality after TAVI. Post-TAVI LVEF recovery was associated with improved long-term outcome.

Clinical value of the fibrosis-4 index in predicting mortality in patients with right ventricular pacing

BACKGROUND

The fibrosis-4 (FIB-4) index has attracted attention as a predictive factor for cardiovascular events and mortality in patients with heart disease. However, its clinical value in patients with implanted pacemakers remains unclear.

METHODS

This study included patients who underwent pacemaker implantation. The FIB-4 index was calculated based on blood tests performed during the procedure. The primary outcome was all-cause mortality, and the secondary outcomes included cardiovascular death, non-cardiovascular death, and major adverse cardiovascular events (MACE; composite of cardiovascular death, heart failure hospitalization, non-fatal myocardial infarction, and non-fatal stroke). The FIB-4 index was stratified into tertiles. Between-group comparisons were performed using log-rank tests and multivariate analysis using Cox proportional hazards. The predictive accuracy and cut-off value of the FIB-4 index were calculated from the receiver operating characteristic curve for all-cause mortality. Finally, based on the calculated cut-off values, the patients were divided into two groups for outcome validation and subgroup analysis.

RESULTS

This study included 201 participants, of whom 38 experienced death during the observation period (median: 1097 days). All-cause mortality, non-cardiovascular death, and MACE differed significantly between groups stratified by the FIB-4 index tertiles (log-rank test: P<0.001, P<0.001, and P = 0.045, respectively). Using Cox proportional hazards analysis, the unadjusted hazard ratio was 4.75 (95% confidence interval [CI]: 2.05-11.0, P<0.001) for Tertile 3 compared to Tertile 1. After adjustment for confounding factors, including sex, the presence or absence of left bundle branch block at baseline, QRS duration during pacing, and pacing rate at the last check, the hazard ratio was 4.79 (95% CI: 2.04-11.2, P<0.001). The cut-off value of the FIB-4 index was 3.75 (area under the curve: 0.72, 95% CI: 0.62-0.82).

CONCLUSIONS

In patients with pacemakers, the FIB-4 index may be a predictor of early all-cause mortality, with a cut-off value of 3.75.

Different heart failure phenotypes of valvular heart disease: the role of mitochondrial dysfunction

Valvular heart disease (VHD)-related heart failure (HF) is a special subtype of HF with an increasingly concerned heterogeneity in pathophysiology, clinical phenotypes, and outcomes. The mechanism of VHD-related HF involves not only mechanical damage to the valve itself but also valve lesions caused by myocardial ischemia. The interactions between them will lead to the occurrence and development of VHD-related HF subtypes. Due to the spatial (combination of different valvular lesions) and temporal effects (sequence of valvular lesions) of valvular damages, it can make the patient's condition more complicated and also make the physicians deal with a dilemma when deciding on a treatment plan. This indicates that there is still lack of deep understanding on the pathogenic mechanism of VHD-related HF subtypes. On the other hand, mitochondrial dysfunction (MitD) is not only associated with the development of numerous cardiac diseases such as atherosclerosis, hypertension, diabetes, and HF but also occurs in VHD. However, the role of MitD in VHD-related HF is still not fully recognized. In this comprehensive review, we aim to discuss the current findings and challenges of different valvular damages derived from HF subtypes as well as the role of MitD in VHD-related HF subtypes.

Quantification of physical activity with prospective activity tracking after transfemoral aortic valve replacement

BACKGROUND

Transcatheter aortic valve replacement (TAVR) is a well-established, safe and effective therapy for severe symptomatic aortic stenosis (AS). The aim of this study was to objectively quantify improvement of physical activity after TAVR, with consideration of different low-gradient AS subtypes.

METHODS AND RESULTS

All patients undergoing TAVR for severe AS were screened. Participants received a wearable activity tracker (Fitbit®) at hospital discharge following TAVR and 6 months thereafter. The difference of median daily steps was defined as surrogate outcome for physical activity. For analysis, patients were grouped into high-gradient (HG) AS (dPmean ≥40 mmHg), classical low-flow low-gradient (LFLG) AS (dPmean <40 mmHg, EF <50%), paradoxical LFLG-AS (dPmean <40 mmHg, EF ≥50%, SVi ≤35 ml/m2) and normal-flow low-gradient (NFLG) AS (dPmean <40 mmHg, EF ≥50%, SVi >35 ml/m2) according to mean transvalvular pressure gradient (dPmean), stroke volume index (SVi) and left-ventricular ejection fraction (LVEF).

RESULTS AND CONCLUSIONS

The analysis is based on 230 patients. The median daily step count was 4409 [IQR 2581-7487] after hospital discharge and 5326 [IQR 3045-8668] 6 months thereafter. Median difference of daily steps was ∆529 [IQR -702-2152]). Patients with HG-AS and paradoxical LFLG-AS showed a significant improvement of daily steps (∆951 [IQR -378-2323], p <0.001 and (∆1392 [IQR -609-4444], p = 0.02, respectively). Patients with classical LFLG-AS showed no statistically relevant improvement of daily steps (∆192 [IQR -687-770], p = 0.79). Patients with NFLG-AS showed a numerical decline in daily steps without statistical significance (∆-300 [IQR -1334-1406], p = 0.67). This first prospective study of this sample size shows significant improvement of physical activity after TAVR with an objective and reproducible method. This was mainly driven by an improvement in patients with HG-AS and paradoxical LFLG-AS.

Proposal criteria of paradoxical low-flow low-gradient aortic stenosis for predicting prognosis in patients undergoing transcatheter aortic valve implantation

BACKGROUND

Paradoxical low-flow, low-gradient (PLF-LG) aortic stenosis (AS) is associated with poor prognosis in patients undergoing transcatheter aortic valve implantation (TAVI). This study aimed to verify the conventional criteria of PLF-LG AS (left ventricular ejection fraction [LVEF] > 50%, mean aortic valve pressure gradient [AVPG] < 40 mm Hg and stroke volume index [SVI] < 35 ml/m² by measuring Doppler method) compatible for predicting prognosis in patients undergoing TAVI.

MATERIALS AND METHODS

A total of 128 consecutive patients who underwent TAVI for AS with LVEF > 50% were enrolled. The primary endpoint was the hospital readmission due to heart failure (HRHF) and the secondary endpoint was all-cause mortality after hospital discharge. The patients were classified by both the conventional criteria of PLF-LG AS and the proposal criteria of PLF-LG AS if mean aortic valve pressure gradient (AVPG) < 40 mmHg and SVI by measuring Simpson's method < cut off value based on the ROC curve for predicting HRHF.

RESULTS

According to the conventional criteria, only 6 patients were diagnosed with PLF-LG AS. However, according to the proposal criteria, 16 patients were diagnosed with PLF-LG AS. Fourteen patients developed HRHF during the follow-up period after TAVI. Based on the ROC curves, SVI by measuring Simpson's method (cut off value = 25 ml/m²) had higher sensitivity and specificity for predicting HRHF (AUC = 0.74, p = 0.0013) than SVI by measuring Doppler method (AUC = 0.63, p = 0.045). The multivariate analysis revealed that PLF-LG AS defined by the proposal criteria (HR: 5.25; 95% CI: 1.60-17.16; p = 0.0073) but not by the conventional criteria was independently associated with HRHF. PLF-LG AS defined by the conventional criteria and the proposal criteria were not associated with all-cause mortality in the univariate analysis.

CONCLUSIONS

Our results demonstrated that new criteria of PLF-LG AS defined as SVI < 25 ml/m² measured by Simpson's method could predict HRHF in patients with severe AS who underwent TAVI.

Prognostic value of the H2 FPEF score in patients undergoing transcatheter aortic valve implantation

Aims

The aim of this study was to assess the prognostic value of the H₂FPEF score in patients undergoing transcatheter aortic valve implantation (TAVI) for severe aortic stenosis (AS) and preserved left ventricular ejection fraction (EF).

Methods and results

In this multicentre study, a total of 832 patients from two German high‐volume centres, who received TAVI for severe AS and preserved EF (≥50%), were identified for calculation of the H₂FPEF score. Patients were dichotomized according to low (0–5 points; n = 570) and high (6–9 points; n = 262) H₂FPEF scores. Kaplan–Meier and Cox regression analyses were applied to assess the prognostic impact of the H₂FPEF score. We observed a decrease in stroke volume index (−2.04 mL/m²/point) and mean transvalvular gradients (−1.14 mmHg/point) with increasing H₂FPEF score translating into a higher prevalence of paradoxical low‐flow, low‐gradient AS among patients with high H₂FPEF score. One year after TAVI, the rates of all‐cause (low vs. high H₂FPEF score: 8.0% vs. 19.4%, P < 0.0001) and cardiovascular (CV) mortality (1.9% vs. 9.0%, P < 0.0001) as well as the rate of CV mortality or rehospitalization for congestive heart failure (6.4% vs. 23.2%, P < 0.0001) were higher in patients with high H₂FPEF score compared with those with low H₂FPEF score. After multivariable analysis, a high H₂FPEF score remained independently predictive of all‐cause mortality [hazard ratio 1.59 (1.28–2.35), P = 0.018] and CV mortality or rehospitalization for congestive heart failure [hazard ratio 2.92 (1.65–5.15), P < 0.001]. Among the H₂FPEF score variables, atrial fibrillation, pulmonary hypertension, and elevated left ventricular filling pressure were the strongest outcome predictors.

Conclusions

The H₂FPEF score serves as an independent predictor of adverse CV and heart failure outcome among TAVI patients with preserved EF. A high H₂FPEF score is associated with the presence of paradoxical low‐flow, low‐gradient AS, the HFpEF in patients with AS. By identifying patients in advanced stages of HFpEF, the H₂FPEF score might be useful as a risk prediction tool in patients with preserved EF scheduled for TAVI.