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Do flow-gradient groups determined by MDCT predict outcomes: validating CT stroke volume
Faisal Rahman1, Pallavi Pandey2, Ankur Pandey3,4
1Division of Cardiology, Johns Hopkins Hospital, Baltimore, MD, USA.
Insights
Computed tomography blood pool based (CT-blp) analysis accurately estimates stroke volume in patients undergoing transcatheter aortic valve replacement (TAVR). This method aids in identifying low-flow, low-gradient aortic stenosis, improving patient stratification for TAVR.
Area of Science:
- Cardiology
- Medical Imaging
- Interventional Cardiology
Background:
- Accurate diagnosis of severe aortic stenosis is challenging, particularly in patients with low-flow states.
- Non-invasive imaging modalities are crucial for timely diagnosis and treatment initiation.
Purpose of the Study:
- To evaluate the accuracy of CT blood pool based (CT-blp) analysis in estimating stroke volume compared to echocardiogram and right heart catheterization.
- To assess the performance of CT-blp in predicting 30-day and 1-year outcomes in patients undergoing transcatheter aortic valve replacement (TAVR).
Main Methods:
- Retrospective, single-center study involving 345 patients with aortic stenosis undergoing TAVR.
- Stroke volume calculated using CT-blp, echocardiogram, and right heart catheterization prior to TAVR.
- Comparison of modality performance in predicting short-term and long-term clinical outcomes.
Main Results:
- CT-blp demonstrated a stronger correlation with cath-derived stroke volume (r=0.60) than echocardiogram (r=0.37).
- No significant difference in mortality was observed between groups stratified by flow and gradient using CT-blp or echo.
- The composite of mortality and hospital readmission was significantly higher in the low-flow, low-gradient group identified by CT-blp (30-day OR 2.6; 1-year OR 1.9).
Conclusions:
- CT-blp provides a reliable estimation of stroke volume, correlating well with invasive measurements in patients evaluated for TAVR.
- CT-blp can effectively stratify patients into flow-gradient groups, aiding in the identification of low-flow, low-gradient aortic stenosis when echocardiography is limited.
- Further research with larger cohorts is warranted to validate these findings and their clinical implications.
Background:
Identifying severe aortic stenosis can be difficult especially among patients with low-flow states compared to normal flow. Non-invasive modalities can aid in the diagnosis for timely treatment.
Methods:
In this retrospective, single-center study of patients with aortic stenosis who underwent transcatheter aortic valve replacement (TAVR), we calculated stroke volume using CT blood pool based (CT-blp) analysis, echocardiogram and right heart catheterization (cath) performed before TAVR. We compared the performance of each modality in predicting 30-day and 1-year outcomes.
Results:
Three-hundred and forty-five patients were included with a median age of 84 (79-88) years and 52.8% females. CT-blp correlated more strongly (r = 0.60) with cath-derived stroke volume than echo (r = 0.37). After stratifying patients into groups based on flow and gradient using echo or CT-blp, there was no difference in mortality with either modality among the groups. However, the composite of mortality and hospital readmission was significantly higher in the low-flow low-gradient group (CT-blp 30-day OR 2.6, 95% CI 1.3-5.3, p < 0.01; 1-year OR 1.9, 95% CI 1.0-3.6; p = 0.04) compared to patients with normal flow high gradients when grouping was performed with CT-blp or echo.
Conclusion:
Using the CT performed on patients pre-TAVR, CT-blp can provide an estimation of stroke volume that correlates well with invasive evaluation. The stroke volume may be used to stratify patient populations being evaluated for TAVR into flow gradient groups when echo is limited and avoid invasive catheterization to help identify patients with low-flow, low-gradient aortic stenosis. Further studies with larger cohorts are required to confirm our findings.
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