Improvement of hemodynamic parameters in aortic stenosis patients with transcatheter valve replacement by using impedance cardiography

Cardiac output in patients with small annuli undergoing transcatheter aortic valve implantation with self-expanding versus balloon expandable valve (COPS-TAVI)

BACKGROUND

There is limited data on cardiac output in patients with small aortic annuli undergoing trans-catheter aortic valve implantation (TAVI) according to the implanted platform of balloon-expandable (BEV) compared to self-expanding valves (SEV).

METHODS

This is a retrospective analysis of consecutive patients with severe aortic stenosis and small annuli who underwent successful TAVI. Cardiac output was measured using echocardiography within 4 weeks following TAVI. Data were recorded and analysed by an experienced operator who was not aware of the type of the implanted valve.

RESULTS

138 patients were included in the analysis, of whom 57 % underwent TAVI with BEV. Clinical and echocardiographic characteristics were comparable between the two platforms, except for more frequent previous cardiac surgery and smaller indexed aortic valve in the BEV group. There was no relationship between computed tomography-derived aortic annulus area and cardiac output post TAVI. When compared to patients who underwent TAVI with BEV, those with SEV had larger cardiac output [mean difference - 0.50 l/min, 95 % CI (-0.99, -0.01)] and cardiac index [mean difference - 0.20 l/min/m2, 95 % CI (-0.47, 0.07)], although the latter did not reach statistical significance. Unlike patients with small body surface area, in those with large body surface area both cardiac output and cardiac index were statistically larger in patients who underwent SEV compared to BEV.

CONCLUSION

Cardiac output, as measured by echocardiography, was larger in patients with small annuli who underwent TAVI procedure with SEV compared to BEV. Such difference was more evident in patients with large body surface area.

Risk factors and predictive model for moderate to severe perivalvular leakage following transcatheter aortic valve replacement

OBJECTIVE

To identify the risk factors associated with moderate to severe perivalvular leakage (PVL) after transcatheter aortic valve replacement (TAVR) and to construct a prediction model for this risk.

METHODS

A retrospective analysis was conducted on 128 patients with severe aortic stenosis who had received TAVR in The Second Hospital of Hebei Medical University from January 2019 to January 2024. The length of the aortic regurgitation bundle and annular circumference ratio were measured by transesophageal echocardiography immediately after the valve implantation. Patients with moderate to severe PVL were included in observation group, while the remaining comprised the control group. Clinical data of the patients were recorded, and univariate and multivariate Logistic regression analyses were performed on factors potentially influencing the development of moderate to severe PVL after surgery. A risk prediction model was constructed correspondingly.

RESULTS

Of the 128 patients, 51 with moderate or severe PVL served as the observation group and the remaining 77 served as the control group. The results of univariate and multivariate analyses identified LVOT coverage index, depth of valve implantation, LVEDd, aortic angulation, LVESD, and calcification volume entered as independent risk factors associated with moderate to severe PVL following TAVR (P<0.05). A predictive model for post-TAVR PVL was constructed by incorporating these significant factors. ROC curve analysis of the prediction model for moderate to severe PVL showed an area under the curve of 0.911.

CONCLUSION

LVOT coverage index, depth of valve implantation, LVEDd, aortic angulation, LVESD, and calcification volume are independent risk factors for moderate to severe PVL in patients with severe aortic stenosis after TAVR. Risk prediction model constructed based on the risk factors are valuable tool for identifying patients at high risk of developing moderate or greater PVL post-surgery.

Association of attenuated leptin signaling pathways with impaired cardiac function under prolonged high-altitude hypoxia

Cardiovascular function and adipose metabolism were markedly influenced under high altitudes. However, the interplay between adipokines and heart under hypoxia remains to be elucidated. We aim to explore alterations of adipokines and underlying mechanisms in regulating cardiac function under high altitudes. We investigated the cardiopulmonary function and five adipokines in Antarctic expeditioners at Kunlun Station (4,087 m) for 20 days and established rats exposed to hypobaric hypoxia (5,000 m), simulating Kunlun Station. Antarctic expeditioners exhibited elevated heart rate, blood pressure, systemic vascular resistance, and decreased cardiac pumping function. Plasma creatine phosphokinase-MB (CK-MB) and platelet-endothelial cell adhesion molecule-1 (sPecam-1) increased, and leptin, resistin, and lipocalin-2 decreased. Plasma leptin significantly correlated with altered cardiac function indicators. Additionally, hypoxic rats manifested impaired left ventricular systolic and diastolic function, elevated plasma CK-MB and sPecam-1, and decreased plasma leptin. Chronic hypoxia for 14 days led to increased myocyte hypertrophy, fibrosis, apoptosis, and mitochondrial dysfunction, coupled with reduced protein levels of leptin signaling pathways in myocardial tissues. Cardiac transcriptome analysis revealed leptin was associated with downregulated genes involved in rhythm, Na+/K+ transport, and cell skeleton. In conclusion, chronic hypoxia significantly reduced leptin signaling pathways in cardiac tissues along with significant pathological changes, thus highlighting the pivotal role of leptin in regulation of cardiac function under high altitudes.

Is the Corrected Carotid Flow Time a Clinically Acceptable Surrogate Hemodynamic Parameter for the Left Ventricular Ejection Time?

OBJECTIVE

The corrected left ventricular ejection time (cLVET) comprises the phase from aortic valve opening to aortic valve closure corrected for heart rate. As a surrogate measure for cLVET, the corrected carotid flow time (ccFT) has been proposed in previous research. The aim of this study was to assess the clinical agreement between cLVET and ccFT in a dynamic clinical setting.

METHODS

Twenty-five patients with severe aortic valve stenosis (AS) were selected for transcatheter aortic valve replacement (TAVR). The cLVET and ccFT were derived from the left ventricular outflow tract (LVOT) and the common carotid artery (CCA), respectively, using pulsed wave Doppler ultrasound. Bazett's (B) and Wodey's (W) equations were used to calculate cLVET and ccFT. Measurements were performed directly before (T1) and after (T2) TAVR. Correlation, Bland-Altman and concordance analyses were performed.

RESULTS

Corrected LVET decreased from T1 to T2 (p < 0.001), with relative reductions of 11% (B) and 9% (W). Corrected carotid flow time decreased (p < 0.001), with relative reductions of 12% (B) and 10% (W). The correlation between cLVET and ccFT was strong for B (ρ = 0.74, p < 0.001) and W (ρ = 0.81, p < 0.001). The bias was -39 ms (B) and -37 ms (W), and the upper and lower levels of agreement were 19 and -98 ms (B) and 5 and -78 ms (W), respectively. Trending ability between cLVET and ccFT was good (concordance 96%) for both B and W.

CONCLUSION

In TAVR patients, the clinical agreement between cLVET and ccFT was acceptable, indicating that ccFT could serve as a surrogate measure for cLVET.