Dynamic changes in aortic impedance after transcatheter aortic valve replacement and its impact on exploratory outcome

• Published in: The International Journal of Cardiovascular Imaging Vol. 33; no. 11; pp. 1693 - 1701
• Main Authors: Kobayashi, Yukari, Kim, Juyong B., Moneghetti, Kegan J., Kobayashi, Yuhei, Zhang, Ran, Brenner, Daniel A., O’Malley, Ryan, Schnittger, Ingela, Fischbein, Michael, Miller, D. Craig, Yeung, Alan C., Liang, David, Haddad, Francois, Fearon, William F.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-11-2017; Springer Nature B.V
• Subjects: Aged; Aged, 80 and over; Aorta - diagnostic imaging; Aorta - physiopathology; Aortic stenosis; Aortic valve; Aortic Valve - diagnostic imaging; Aortic Valve - physiopathology; Aortic Valve - surgery; Aortic Valve Stenosis - diagnostic imaging; Aortic Valve Stenosis - mortality; Aortic Valve Stenosis - physiopathology; Aortic Valve Stenosis - surgery; Arterial Pressure; Biomechanical Phenomena; Blood pressure; Cardiac Imaging; Cardiology; Chi-Square Distribution; Echocardiography, Doppler, Color; Electrocardiography; Female; Heart; Heart diseases; Humans; Imaging; Impedance; Kaplan-Meier Estimate; Logistic Models; Male; Medicine; Medicine & Public Health; Mortality; Multivariate Analysis; Original Paper; Patients; Prospective Studies; Radiology; Recovery of Function; Regional Blood Flow; Risk Factors; Severity of Illness Index; Stenosis; Stress, Mechanical; Stroke; Stroke Volume; Time Factors; Transcatheter Aortic Valve Replacement - adverse effects; Transcatheter Aortic Valve Replacement - mortality; Treatment Outcome; Ventricle; Ventricular Function, Left; Strain imaging; Ventricular impedance; Transcatheter aortic valve replacement
• ISSN: 1569-5794; 1573-0743; 1875-8312
• DOI: 10.1007/s10554-017-1155-6

Valvulo-arterial impedance (Zva) has been shown to predict worse outcome in medically managed aortic stenosis (AS) patients. We aimed to investigate the association between Zva and left ventricular (LV) adaptation and to explore the predictive value of Zva for cardiac functional recovery and outcome after transcatheter aortic valve replacement (TAVR). We prospectively enrolled 128 patients with AS who underwent TAVR. Zva was calculated as: (systolic blood pressure + mean transaortic gradient)/stroke volume index). Echocardiographic assessment occurred at baseline, 1-month and 1-year after TAVR. The primary endpoints were to investigate associations between Zva and global longitudinal strain (GLS) at baseline as well as GLS change after TAVR. The secondary was to compare all-cause mortality after TAVR between patients with pre-defined Zva (=5 mmHg m
2
/ml), stroke volume index (=35 ml/m
2
), and GLS (=−15%) cutoffs. The mean GLS was reduced (−13.0 ± 3.2%). The mean Zva was 5.2 ± 1.6 mmHg*m
2
/ml with 55% of values ≥5.0 mmHg*m
2
/ml, considered to be abnormally high. Higher Zva correlated with worse GLS (r = −0.33, p < 0.001). After TAVR, Zva decreased significantly (5.1 ± 1.6 vs. 4.5 ± 1.6 mmHg*m
2
/ml, p = 0.001). A reduction of Zva at 1-month was associated with GLS improvement at 1-month (r = −0.31, p = 0.001) and at 1-year (r = −0.36 and p = 0.001). By Kaplan–Meier analysis, patients with higher Zva at baseline had higher mortality (Log-rank p = 0.046), while stroke volume index and GLS did not differentiate outcome (Log-rank p = 0.09 and 0.25, respectively). As a conclusion, Zva is correlated with GLS in AS as well as GLS improvement after TAVR. Furthermore, a high baseline Zva may have an additional impact to traditional parameters on predicting worse mortality after TAVR.