Dataset Information

Invasive versus non-invasive assessment of valvuloarterial impedance in severe aortic stenosis.

ABSTRACT: BACKGROUND:As a measure of the global left ventricular afterload, valvuloarterial impedance (ZVA) can be estimated using transthoracic echocardiography (TTE) and invasive measuring methods. The objective of this study was to compare the performance of TTE in measuring ZVA with invasive haemodynamics, direct Fick and thermodilution (TD), in patients with severe aortic stenosis (AS). METHODS:This is a retrospective cohort study of 66 patients with severe AS who underwent TTE and bilateral heart catheterisation preaortic valve replacement. ZVA was calculated non-invasively from TTE and invasively using TD and Fick. The differences in measurements were estimated using a generalised estimating equation approach. The exchangeability of the measurements from different methods was evaluated under binary risk stratification rules. RESULTS:The mean±SD?ZVA by TTE was 4.6±1.4 vs 4.9±1.6 by TD vs 4.3±1.2?mm Hg m2/mL by Fick. From multivariate analyses, ZVA by TTE was 5.9% (95%?CI -15.0 to 2.5) lower than by TD and 5.9% (95% CI -1.5 to 12.8) higher than by Fick. At the same time, ZVA by TD was 12.5% (3.0 to 22.9) higher than with Fick. Risk classifications for ZVA-based binary decision rules showed poor agreement between TTE and invasive methods (kappa ?0.3). CONCLUSIONS:The differences in ZVA estimates between TTE and invasive standards do not appear to exceed those between the standards. As such TTE-based estimates may be deemed acceptable as a clinical measure of global haemodynamic load. However, TTE-based and invasive measurements may not be interchangeable to identify patients at risk using binary classification rules based on ZVA.

SUBMITTER: Stanberry L

PROVIDER: S-EPMC7213872 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature

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Invasive versus non-invasive assessment of valvuloarterial impedance in severe aortic stenosis.

Stanberry Lisa L Ahmed Aisha A Sorajja Paul P Cavalcante Joao L JL Gossl Mario M

Open heart 20200401 1

<h4>Background</h4>As a measure of the global left ventricular afterload, valvuloarterial impedance (ZVA) can be estimated using transthoracic echocardiography (TTE) and invasive measuring methods. The objective of this study was to compare the performance of TTE in measuring ZVA with invasive haemodynamics, direct Fick and thermodilution (TD), in patients with severe aortic stenosis (AS).<h4>Methods</h4>This is a retrospective cohort study of 66 patients with severe AS who underwent TTE and bil ...[more]

PMID: 32366520

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Project description:AimsTo investigate myocardial fibrosis (MF) in a large series of severe aortic stenosis (AS) patients using invasive biopsy and non-invasive imaging.Methods and resultsOne hundred thirty-three patients with severe, symptomatic AS accepted for surgical aortic valve replacement underwent cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) and extracellular volume fraction (ECV) quantification. Intra-operative left ventricular (LV) biopsies were performed by needle or scalpel, yielding tissue with (n = 53) and without endocardium (n = 80), and compared with 10 controls. Myocardial fibrosis occurred in three patterns: (i) thickened endocardium with a fibrotic layer; (ii) microscopic scars, with a subendomyocardial predominance; and (iii) diffuse interstitial fibrosis. Collagen volume fraction (CVF) was elevated (P < 0.001) compared with controls, and higher (P < 0.001) in endocardium-containing samples with a decreasing CVF gradient from the subendocardium (P = 0.001). Late gadolinium enhancement correlated with CVF (P < 0.001) but not ECV. Both LGE and ECV correlated independently (P < 0.001) with N-terminal pro-brain natriuretic peptide and high-sensitivity-troponin T. High ECV was also associated with worse LV remodelling, left ventricular ejection fraction and functional capacity. Combining high ECV and LGE better identified patients with more adverse LV remodelling, blood biomarkers and histological parameters, and worse functional capacity than each parameter alone.ConclusionMyocardial fibrosis in severe AS is complex, but three main patterns exist: endocardial fibrosis, microscars (mainly in the subendomyocardium), and diffuse interstitial fibrosis. Neither histological CVF nor the CMR parameters ECV and LGE capture fibrosis in its totality. A combined, multi-parametric approach with ECV and LGE allows best stratification of AS patients according to the response of the myocardial collagen matrix.

Project description:BackgroundDecisions in the management of aortic stenosis are based on the peak pressure drop, captured by Doppler echocardiography, whereas gold standard catheterization measurements assess the net pressure drop but are limited by associated risks. The relationship between these two measurements, peak and net pressure drop, is dictated by the pressure recovery along the ascending aorta which is mainly caused by turbulence energy dissipation. Currently, pressure recovery is considered to occur within the first 40-50 mm distally from the aortic valve, albeit there is inconsistency across interventionist centers on where/how to position the catheter to capture the net pressure drop.MethodsWe developed a non-invasive method to assess the pressure recovery distance based on blood flow momentum via 4D Flow cardiovascular magnetic resonance (CMR). Multi-center acquisitions included physical flow phantoms with different stenotic valve configurations to validate this method, first against reference measurements and then against turbulent energy dissipation (respectively n = 8 and n = 28 acquisitions) and to investigate the relationship between peak and net pressure drops. Finally, we explored the potential errors of cardiac catheterisation pressure recordings as a result of neglecting the pressure recovery distance in a clinical bicuspid aortic valve (BAV) cohort of n = 32 patients.ResultsIn-vitro assessment of pressure recovery distance based on flow momentum achieved an average error of 1.8 ± 8.4 mm when compared to reference pressure sensors in the first phantom workbench. The momentum pressure recovery distance and the turbulent energy dissipation distance showed no statistical difference (mean difference of 2.8 ± 5.4 mm, R2 = 0.93) in the second phantom workbench. A linear correlation was observed between peak and net pressure drops, however, with strong dependences on the valvular morphology. Finally, in the BAV cohort the pressure recovery distance was 78.8 ± 34.3 mm from vena contracta, which is significantly longer than currently accepted in clinical practise (40-50 mm), and 37.5% of patients displayed a pressure recovery distance beyond the end of the ascending aorta.ConclusionThe non-invasive assessment of the distance to pressure recovery is possible by tracking momentum via 4D Flow CMR. Recovery is not always complete at the ascending aorta, and catheterised recordings will overestimate the net pressure drop in those situations. There is a need to re-evaluate the methods that characterise the haemodynamic burden caused by aortic stenosis as currently clinically accepted pressure recovery distance is an underestimation.

Project description:BACKGROUND:Transcatheter aortic valve implantation (TAVI) is criticized by some as an expensive treatment in super-elder patients with limited life expectancy. However, there is a knowledge gap regarding the magnitude of clinical benefit provided by TAVI in comparison with conservative management in patients with severe aortic stenosis (AS) in real clinical practice, which would be important in the decision making for TAVI. METHODS:We combined two independent registries, namely CURRENT AS and K-TAVI registries. CURRENT AS was a multicenter registry enrolling 3815 consecutive patients with severe AS irrespective to treatment modalities between January 2003 and December 2011. K-TAVI was a multicenter, prospective registry including 449 consecutive patients with severe AS, who underwent TAVI with SAPIEN XT balloon-expandable valves between October 2013 and June 2016. In these 2 registries, 449 patients received TAVI and 894 patients were managed with conservative strategy. We conducted propensity score matching and finally obtained a cohort of 556 patients (278 patients for each group) for the analysis. The primary outcome measures were all-cause death and heart failure (HF) hospitalization at 2-year. RESULTS:The cumulative 2-year incidences of all-cause death and HF hospitalization were significantly lower in the TAVI group than in the conservative group (16.8% versus 36.6%, P<0.001, and 10.7% versus 37.2%, P<0.001). After adjusting the residual confounders, TAVI reduced the risks of all-cause death (HR, 0.46; 95%CI, 0.32-0.69; P = 0.0001) and HF hospitalizations (HR, 0.25; 95%CI, 0.16-0.40; P<0.0001) compared with conservative strategy. There was no difference in the cumulative incidence of non-cardiovascular death between the 2 groups. CONCLUSIONS:TAVI in the early Japanese experience was associated with striking risk reduction for all-cause death as well as HF hospitalization as compared with the historical cohort of patients with severe AS who were managed conservatively just before introduction of TAVI in Japan.

Dataset Information

Invasive versus non-invasive assessment of valvuloarterial impedance in severe aortic stenosis.

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Invasive versus non-invasive assessment of valvuloarterial impedance in severe aortic stenosis.

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