Background: Ejection time (ET) and Acceleration time (AT) have been described as echocardiographic markers for aortic stenosis (AS).(Gamaza-Chulián et al. 2017) Moreover, in a recent study time between invasively measured left ventricular and aortic systolic pressure peaks (T-LVAo) was associated with anatomic AS severity.(Sato et al. 2019) However, the diagnostic value of these invasively measured parameters has not been validated in a larger patient cohort and their prognostic impact in AS patients undergoing transcatheter aortic valve implantation (TAVI) remains unknown.

Purpose: We aimed to assess the diagnostic value and prognostic impact of ET, AT, and T-LVAo as assessed by invasive measurements in patients undergoing TAVI for severe AS.

Methods: This retrospective single-centre analysis studied 1478 patients undergoing TAVI from 2014 to 2019 for severe AS. All patients received echocardiographic, multislice computed tomography (MSCT) and invasive hemodynamic evaluation with simultaneous pressure measurements in left ventricle and aorta prior to TAVI. Anatomic AS severity was assessed according to MSCT-derived aortic valve calcification density (AVC_d) defined as calcium volume per annulus area. All hemodynamic parameters were calculated offline using a dedicated software (Schwarzer Cardiotek).

Results: Medians of invasively derived parameters were 70.0 ms (46.0-98.0) for T-LVAo, 308.0 ms (276.0-336.0) for ET, 180.0 ms (146.0-206.0) for AT. 

In multivariable linear regression higher T-LVAo was significantly associated with AVC_d (β per SD 9.15;P<0.001), Pmean (β per SD 7.42;P<.001) and EOA (β per SD 2.47;P=.048) indicating high diagnostic value. In comparison to T-LVAo, ET and AT showed weaker association with AS severity by means of AVCd and EOA. According to both, uni- and multivariable analyses, T-LVAo showed no prognostic impact among TAVI patients. In contrast, ET as well as AT were significantly associated with mortality. The optimal cutoff for death (C_D) according to C-statistic was 274 ms for ET and 158 ms for AT. Patients with ET or AT ≥ C_Dshowed lower short and mid-term mortality rates compared to patients with ET or AT < C_D (ET ≥ vs. < C_D: mortality at 1-year: 14.5 vs. 31.9%, 3-years: 28.3 vs. 53.5%, all p<0.001; AT ≥ vs < C_D: mortality at 1-year: 15.5 vs. 25.9%, p<0.001, 3-years: 34.0 vs. 41.1%, p<0.001). Moreover, multivariable cox regressions for mortality identified ET ≥C_D (HR 0.58 [95% CI 0.43-0.77; p<0.001]) and AT ≥C_D (HR 0.65 [95% CI 0.49-0.86; p=0.0027]) to be associated with beneficial outcome after TAVI, independent from clinical risk factors and echocardiography-derived parameters like LVEF, mean gradient or stroke volume index. 

Conclusion: T-LVAo provides very high diagnostic value as it is strongly associated  with AVC_d, Pmean and EOA. Moreover, ET and AT are independent outcome predictors beyond clinical risk factors and standard echocardiographic parameters in AS patients following TAVI. Accordingly, these investigational hemodynamic parameters could be of considerable value in diagnostic evaluation and risk assessment of patients scheduled for TAVI. 

Gamaza-Chulián, S et al. 2017. “Acceleration Time and Ratio of Acceleration Time to Ejection Time in Aortic Stenosis.” JASE 30(10): 947–55.

Sato, K et al. 2019. “Association of Time between Left Ventricular and Aortic Systolic Pressure Peaks with Severity of Aortic Stenosis and Calcification of Aortic Valve.” JAMA Cardiology 4(6): 549–55.