Prognosis of paradoxical low-flow low-gradient aortic stenosis after transcatheter aortic valve replacement

Histological assessment of cardiac amyloidosis in patients undergoing transcatheter aortic valve replacement

AIMS

Studies have reported a strongly varying co-prevalence of aortic stenosis (AS) and cardiac amyloidosis (CA). We sought to histologically determine the co-prevalence of AS and CA in patients undergoing transcatheter aortic valve replacement (TAVR). Consequently, we aimed to derive an algorithm to identify cases in which to suspect the co-prevalence of AS and CA.

METHODS AND RESULTS

In this prospective, monocentric study, endomyocardial biopsies of 162 patients undergoing TAVR between January 2017 and March 2021 at the University Medical Centre Göttingen were analysed by one pathologist blinded to clinical data using haematoxylin-eosin staining, Elastica van Gieson staining, and Congo red staining of endomyocardial biopsies. CA was identified in only eight patients (4.9%). CA patients had significantly higher N-terminal pro-brain natriuretic peptide (NT-proBNP) levels (4356.20 vs. 1938.00 ng/L, P = 0.034), a lower voltage-to-mass ratio (0.73 vs. 1.46 × 10-2 mVm2/g, P = 0.022), and lower transaortic gradients (Pmean 17.5 vs. 38.0 mmHg, P = 0.004) than AS patients. Concomitant CA was associated with a higher prevalence of post-procedural acute kidney injury (50.0% vs. 13.1%, P = 0.018) and sudden cardiac death [SCD; P (log-rank test) = 0.017]. Following propensity score matching, 184 proteins were analysed to identify serum biomarkers of concomitant CA. CA patients expressed lower levels of chymotrypsin (P = 0.018) and carboxypeptidase 1 (P = 0.027). We propose an algorithm using commonly documented parameters-stroke volume index, ejection fraction, NT-proBNP levels, posterior wall thickness, and QRS voltage-to-mass ratio-to screen for CA in AS patients, reaching a sensitivity of 66.6% with a specificity of 98.1%.

CONCLUSIONS

The co-prevalence of AS and CA was lower than expected, at 4.9%. Despite excellent 1 year mortality, AS + CA patients died significantly more often from SCD. We propose a multimodal algorithm to facilitate more effective screening for CA containing parameters commonly documented during clinical routine. Proteomic biomarkers may yield additional information in the future.

Diastolic dysfunction and clinical outcomes after transcatheter or surgical aortic valve replacement in patients with atypical aortic valve stenosis

BACKGROUND

Diastolic dysfunction is a predictor of poor outcomes in many cardiovascular conditions. At present, it is unclear whether diastolic dysfunction predicts adverse outcomes in patients with atypical aortic stenosis who undergo aortic valve replacement (AVR).

METHODS

Five hundred and twenty-three patients who underwent transcatheter AVR (TAVR) (n = 303) and surgical AVR (SAVR) (n = 220) at a single institution were included in our analysis. Baseline left and right heart invasive hemodynamics were assessed. Baseline transthoracic echocardiograms were reviewed to determine aortic stenosis subtype and parameters of diastolic dysfunction. Aortic stenosis subtype was categorized as typical (normal flow, high-gradient) aortic stenosis, classical, low-flow, low-gradient (cLFLG) aortic stenosis, and paradoxical, low-flow, low-gradient (pLFLG) aortic stenosis. Cox proportional hazard models were utilized to examine the relation between invasive hemodynamic or echocardiographic variables of diastolic dysfunction, aortic stenosis subtype, and all-cause mortality. Propensity-score analysis was performed to study the relation between aortic stenosis subtype and the composite outcome [death/cerebrovascular accident (CVA)].

RESULTS

The median STS risk was 5.3 and 2.5% for TAVR and SAVR patients, respectively. Relative to patients with typical aortic stenosis, patients with atypical (cLFLG and pLFLG) aortic stenosis displayed a significantly higher prevalence of diastolic dysfunction (LVEDP ≥ 20mmHg, PCWP ≥ 20mmHg, echo grade II or III diastolic dysfunction, and echo-PCWP ≥ 20mmHg) and, independently of AVR treatment modality, had a significantly increased risk of death. In propensity-score analysis, patients with atypical aortic stenosis had higher rates of death/CVA than typical aortic stenosis patients, independently of diastolic dysfunction and AVR treatment modality.

CONCLUSION

We demonstrate the novel observation that compared with patients with typical aortic stenosis, patients with atypical aortic stenosis have a higher burden of diastolic dysfunction. We corroborate the worse outcomes previously reported in atypical versus typical aortic stenosis and demonstrate, for the first time, that this observation is independent of AVR treatment modality. Furthermore, the presence of diastolic dysfunction does not independently predict outcome in atypical aortic stenosis regardless of treatment type, suggesting that other factors are responsible for adverse clinical outcomes in this higher risk cohort.

Prognostic value of coronary microvascular dysfunction in patients with aortic stenosis and nonobstructed coronary arteries

BACKGROUND

Patients with aortic valve stenosis have been postulated to have coronary microvascular dysfunction (CMD) contributing to the clinical symptoms and adverse outcomes. The coronary angiography (CAG)-derived index of microcirculatory resistance (caIMR) is proposed as a novel, less invasive and pressure-wire-free index to assess CMD. This study aimed to quantify CMD assessed by caIMR and investigate its prognostic impact in patients with aortic valve stenosis.

METHODS

This study included 77 moderate or severe aortic valve stenosis patients with no obstructive coronary disease (defined as having no stenosis more than 50% in diameter) who underwent caIMR measurement. CMD was defined by caIMR at least 25. Major adverse cardiovascular events (MACE) were the clinical outcomes during the median 40 months of follow-up.

RESULTS

The incidence of CMD was 47.7%. Seventeen MACE occurred during the follow-up duration. CMD was associated with an increased risk of MACE (log-rank P < 0.001) and an independent predictor of clinical outcomes [hazard ratio 5.467, 95% confidence interval (CI) 1.393-21.458; P = 0.015]. The receiver-operating characteristic (ROC) curve analysis demonstrated that caIMR could provide a significant predictive value for MACE in aortic valve stenosis patients (AUC 0.785, 95% CI 0.609-0.961, P < 0.001). In addition, the risk of MACE was higher in CMD patients with severe aortic valve stenosis (log-rank P < 0.001) and no aortic valve replacement (log-rank P = 0.003) than in other groups.

CONCLUSION

Aortic valve stenosis patients demonstrated markedly impaired caIMR. CMD assessed by caIMR increases the risk of MACE and is an independent predictor of adverse outcomes in aortic valve stenosis patients. This finding suggests that using caIMR in the clinical assessment may help identify high-risk groups and stimulate earlier intervention.

Clinical Outcomes in High-Gradient, Classical Low-Flow, Low-Gradient, and Paradoxical Low-Flow, Low-Gradient Aortic Stenosis After Transcatheter Aortic Valve Implantation: A Report From the SwissTAVI Registry

Background In view of the rising global burden of severe symptomatic aortic stenosis, its early recognition and treatment is key. Although patients with classical low-flow, low-gradient (C-LFLG) aortic stenosis have higher rates of death after transcatheter aortic valve implantation (TAVI) when compared with patients with high-gradient (HG) aortic stenosis, there is conflicting evidence on the death rate in patients with severe paradoxical low-flow, low-gradient (P-LFLG) aortic stenosis. Therefore, we aimed to compare outcomes in real-world patients with severe HG, C-LFLG, and P-LFLG aortic stenosis undergoing TAVI. Methods and Results Clinical outcomes up to 5 years were addressed in the 3 groups of patients enrolled in the prospective, national, multicenter SwissTAVI registry. A total of 8914 patients undergoing TAVI at 15 heart valve centers in Switzerland were analyzed for the purpose of this study. We observed a significant difference in time to death at 1 year after TAVI, with the lowest observed in HG (8.8%) aortic stenosis, followed by P-LFLG (11.5%; hazard ratio [HR], 1.35 [95% CI, 1.16-1.56]; P<0.001) and C-LFLG (19.8%; HR, 1.93 [95% CI, 1.64-2.26]; P<0.001) aortic stenosis. Cardiovascular death showed similar differences between the groups. At 5 years, the all-cause death rate was 44.4% in HG, 52.1% in P-LFLG (HR, 1.35 [95% CI, 1.23-1.48]; P<0.001), and 62.8% in C-LFLG aortic stenosis (HR, 1.7 [95% CI, 1.54-1.88]; P<0.001). Conclusions Up to 5 years after TAVI, patients with P-LFLG have higher death rates than patients with HG aortic stenosis but lower death rates than patients with C-LFLG aortic stenosis.