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Clinical and Echocardiographic Characteristics of Flow-Based Classification Following Balloon-Expandable
Oludamilola Akinmolayemi1, Denizhan Ozdemir1, Philippe Pibarot2
1Columbia University Irving Medical Center/New York Presbyterian Hospital, New York, New York, USA.
Insights
Transcatheter heart valve (THV) function is influenced by blood flow state. Considering stroke volume index (SVI) before and after transcatheter aortic valve replacement (TAVR) is crucial for accurate hemodynamic assessment.
Area of Science:
- Cardiology
- Biomedical Engineering
- Medical Imaging
Background:
- Echocardiographic measures for transcatheter heart valve (THV) function were previously based on pooled data.
- The impact of flow state on THV function before and after transcatheter aortic valve replacement (TAVR) was not well-defined.
Purpose of the Study:
- To evaluate normal echocardiographic hemodynamics for balloon-expandable THVs.
- To analyze these hemodynamics based on stroke volume index (SVI) groupings.
Main Methods:
- Analysis of severe aortic stenosis patients from PARTNER 1, 2, and 3 trials.
- Grouping patients into low-flow (SVI <35 mL/m²) and normal-flow (SVI ≥35 mL/m²) categories.
- Collection of echocardiographic data (mean gradient, EOA, DVI) at baseline and 30 days post-TAVR.
Main Results:
- Patients with low baseline SVI had distinct demographic and hemodynamic profiles.
- Post-TAVR, flow state shifts occurred in a significant proportion of patients.
- Hemodynamic parameters (EOA, mean gradient, DVI) were significantly lower in the low-flow group post-TAVR.
Conclusions:
- Blood flow state significantly impacts THV hemodynamics.
- Both baseline and post-TAVR SVI are essential for predicting and assessing THV function.
- The findings highlight the importance of considering flow state to avoid misinterpreting prosthesis-patient mismatch.
Background:
Current expected normal echocardiographic measures of transcatheter heart valve (THV) function were derived from pooled cohorts of the randomized trials; however, THV function by flow state before or following transcatheter aortic valve replacement (TAVR) has not been previously reported.
Objectives:
This study sought to assess the expected normal echocardiographic hemodynamics for the balloon-expandable THV grouped by stroke volume index (SVI).
Methods:
Patients with severe aortic stenosis enrolled in PARTNER (Placement of Aortic Transcatheter Valves) 1 (high/extreme surgical risk), PARTNER 2 (intermediate surgical risk), or PARTNER 3 (low surgical risk) trials with complete core laboratory echocardiography were included. Patients were grouped by low-flow (SVILOW <35 mL/m2) and normal-flow (SVINORMAL ≥35 mL/m2). Mean gradient, effective orifice area (EOA), and Doppler velocity index (DVI) were collected at baseline and at 30 days post-TAVR. Prosthesis-patient mismatch (PPM) was both calculated and predicted from normative data, using defined criteria.
Results:
In the entire population (N = 4,991), mean age was 81.8 years, 58% of patients were male, and 42% had low flow. Compared with patients with baseline SVINORMAL, those with SVILOW were more likely to be male; have more comorbidities; and lower left ventricular ejection fraction, mean gradient, and EOA. Post-TAVR, SVILOW increased to SVINORMAL in 17.3% and SVINORMAL decreased to SVILOW in 12.3% of patients. Using baseline SVI, follow-up EOA, mean gradient, and DVI for patients with SVILOW tended to be lower than for patients with SVINORMAL. Using the post-TAVR SVI, follow-up EOA, mean gradient, and DVI were significantly lower for patients with SVILOW than for those with SVINORMAL (P < 0.001 for all). The incidence of calculated, but not predicted, severe PPM was higher in patients with low flow than it was in patients with normal flow, suggesting pseudo-PPM in the presence of low flow.
Conclusions:
This study demonstrates that flow affects THV hemodynamics and both baseline and follow-up SVI should be considered when predicting THV hemodynamics prior to TAVR, as well as assessing valve function following valve implantation.
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