Diagnostic value and prognostic impact of various invasively derived hemodynamic parameters in patients with severe aortic stenosis undergoing TAVI

Background

Ejection time (ET) and Acceleration time (AT) have been described as echocardiographic markers for aortic stenosis (AS).1 Moreover, in a recent study time between invasively measured left ventricular and aortic systolic pressure peaks (T-LVAo) was associated with anatomic AS severity.2 However, the diagnostic value of these 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 (AVCd) defined as calcium volume per annulus area. All hemodynamic parameters were calculated offline using a dedicated software.

Results

Median patients' age was 81.2 (76.8–84.7) years and 807 (54.6%) were women. Predicted operative risk for mortality was 3.8 (2.6–5.7)% according to STS Score. 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 spline analysis correlation of T-LVAo (Spearman: r=0.35; p<0.001) and ET (Spearman: r=0.18; p<0.001) with AVCd was significant but weak. AT showed negligible correlation with ACVd (Spearman: r=−0.05; p=0.089). The optimal cutoff for death (CD) according to C-statistic was 274 ms for ET and 158 ms for AT. Patients with ET or AT ≥ CD showed lower short and mid-term mortality rates compared to patients with ET or AT < CD (ET ≥ vs. < CD: mortality at 1-year: 14.5 vs. 31.9%, 3-years: 28.3 vs. 53.5%, all p<0.001; AT ≥ vs < CD: mortality at 1-year: 15.5 vs. 25.9%, p<0.001, 3-years: 34.0 vs. 41.0%, p=0.0032). Moreover, multivariate analysis for mortality identified ET (HR 0.58 [95% CI 0.43–0.77; p<0.001]) and AT (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. In contrast, T-LVAo showed no prognostic impact according to uni- or multivariate analyses.

Conclusion

T-LVAo provides the highest diagnostic value among the investigational hemodynamic parameters, however correlation with AVCd was weak. ET and AT are strong independent outcome predictors beyond clinical risk factors and standard echocardiographic parameters in AS patients following TAVI. Accordingly, use of ET and AT might improve risk assessment in patients scheduled for TAVI.

Funding Acknowledgement

Type of funding sources: None.

Long-Term survival and functional status in patients with elevated mitral valve pressure gradient after transcatheter mitral valve repair

Background

A growing number of patients are currently treated for severe mitral regurgitation (MR) using a transcatheter mitral valve repair (TMVr). In clinical routine, the potential risk of elevated post-procedural mitral valve pressure gradient (MPG) may prohibit optimal MR reduction driven by the avoidance of additional clip implantations. Thus, the unfavorable impact on survival and functional outcome of increased MPG in patients undergoing TMVr is currently debatable.

Methods

In this single-center, prospective study, survival and functional outcome of 780 consecutive patients with severe MR undergoing TMVr between September 2008 and January 2020 were investigated. After exclusion of patients with unsuccessful procedure and those lost to follow-up, data of 676 patients with a median follow-up time of 5.26 (5.11, 5.51) years were analyzed. MPG was determined by transthoracic echocardiography at discharge and considered elevated in excess of 4.5 mmHg. Kaplan-Meier analysis as well as multivariable Cox regression models were performed for the impact on elevated MPG on 5-year outcomes for the subgroups of functional MR (FMR) and degenerative MR (DMR). The primary outcome measure was a combined endpoint of death or rehospitalization for congestive heart failure.

Results

Among 676 patients undergoing TMVr (mean age 74.6±8.5 years, 59.0% male, median STS Score 3.9 [interquartile range 2.5; 6.0]), 179 (26.4%) patients had elevated MPG >4.5 mmHg. FMR was present in 426 (63.0%) patients. In the overall patient cohort, Kaplan-Meier and Cox Regression analyses could not demonstrate significant differences for the combined endpoint (p=0.99). In contrast, subgroup analysis according to MR etiology indicated a significant adverse influence of elevated MPG on the combined endpoint as well as functional outcome in patients with DMR, but not with FMR (Figure 1). After adjustment, multivariate Cox Regression analysis showed an inferior prognosis in patients with DMR and elevated MVPG >4.5 mmHg (hazard ratio 1.79 [1.17, 2.72], p=0.0069, Figure 2).

Conclusions

TMVr-patients with DMR and measurable elevated post-procedural MVPG face an inferior prognosis and reduced functional outcomes compared to patients with FMR.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Tracking heart surface features to determine myocardial contrast agent enrichment

Fluorescent cardiac imaging can be applied for intraoperative quality control after a coronary bypass grafting surgery to ensure the myocardial perfusion by evaluating the increasing contrast agent enrichment in the heart. The motion due to the beating heart impedes the interpretation of the contrast agent enrichment in the vessels and leads to noisy enrichment curves. We propose tracking of the heart surface features to compensate for the motion of the beating heart and thereby improve the analysis of the contrast agent enrichment. Furthermore, we propose a vessel segmentation pipeline for a local evaluation of contrast agent enrichment directly in the vessels.