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Published on: August 14, 2019
Clinical Significance of Diffusion-Weighted Brain MRI Lesions After TAVR: Results of a Patient-Level Pooled Analysis
Alexandra J Lansky1, Daniel Grubman1, Michael G Dwyer2
1Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA; Yale Cardiovascular Research Group, New Haven, Connecticut USA.
Background:
Acute brain infarction detected by diffusion-weighted magnetic resonance imaging (DW-MRI) is common after transcatheter aortic valve replacement (TAVR), but its clinical relevance is uncertain.
Objectives:
The authors investigated the relationship between DW-MRI total lesion number (TLN), individual lesion volume (ILV), and total lesion volume (TLV) and clinical stroke outcomes after TAVR.
Methods:
Patient-level data were pooled from 4 prospective TAVR embolic protection studies, with consistent predischarge DW-MRI acquisition and core laboratory analysis. C-statistic was used to determine the best DW-MRI measure associated with clinical stroke.
Results:
A total of 495 of 603 patients undergoing TAVR completed the predischarge DW-MRI. At 30 days, the rate of clinical ischemic stroke was 6.9%. Acute ischemic brain injury was seen in 85% of patients with 5.5 ± 7.3 discrete lesions per patient, mean ILV of 78.2 ± 257.1 mm3, and mean TLV of 555 ± 1,039 mm3. The C-statistic was 0.84 for TLV, 0.81 for number of lesions, and 0.82 for maximum ILV in predicting ischemic stroke. On the basis of the TLV cutpoint as defined by receiver operating characteristic (ROC), patients with a TLV >500 mm3 (vs TLV ≤500 mm3) had more ischemic stroke (18.2% vs 2.3%; P < 0.0001), more disabling strokes (8.8% vs 0.9%; P < 0.0001), and less complete stroke recovery (44% vs 62.5%; P = 0.001) at 30 days.
Conclusions:
Our study confirms that the number, size, and total volume of acute brain infarction defined by DW-MRI are each associated with clinical ischemic strokes, disabling strokes, and worse stroke recovery in patients undergoing TAVR and may have value as surrogate outcomes in stroke prevention trials. (A Prospective, Randomized Evaluation of the TriGuard™ HDH Embolic Deflection Device During TAVI [DEFLECT III]; NCT02070731) (A Study to Evaluate the Neuro-embolic Consequences of TAVR [NeuroTAVR]; NCT02073864) (The REFLECT Trial: Cerebral Protection to Reduce Cerebral Embolic Lesions After Transcatheter Aortic Valve Implantation [REFLECT I]; NCT02536196) (The REFLECT Trial: Cerebral Protection to Reduce Cerebral Embolic Lesions After Transcatheter Aortic Valve Implantation [REFLECT II]; NCT02536196).
Insights
Acute brain infarction after transcatheter aortic valve replacement (TAVR) is common. Diffusion-weighted MRI measures like total lesion volume (TLV) predict clinical stroke outcomes, suggesting their use in TAVR stroke prevention trials.
Area of Science:
- Cardiovascular Medicine
- Neurology
- Radiology
Background:
- Acute brain infarction is frequently detected by diffusion-weighted magnetic resonance imaging (DW-MRI) after transcatheter aortic valve replacement (TAVR).
- The clinical significance of these DW-MRI findings remains uncertain.
- Understanding the relationship between imaging findings and clinical outcomes is crucial for patient management and trial design.
Purpose of the Study:
- To investigate the association between DW-MRI metrics (total lesion number, individual lesion volume, and total lesion volume) and clinical stroke outcomes post-TAVR.
- To identify the most predictive DW-MRI measure for clinical stroke after TAVR.
- To evaluate the utility of these imaging markers as surrogate outcomes in stroke prevention trials.
Main Methods:
- Pooled patient-level data from four prospective TAVR embolic protection studies.
- Standardized predischarge DW-MRI acquisition and core laboratory analysis.
- Utilized C-statistic to determine the best DW-MRI measure associated with clinical stroke.
Main Results:
- 85% of TAVR patients exhibited acute ischemic brain injury on DW-MRI.
- Total lesion volume (TLV) demonstrated the highest predictive value (C-statistic=0.84) for ischemic stroke.
- Patients with TLV >500 mm³ had significantly higher rates of ischemic stroke (18.2% vs 2.3%), disabling strokes (8.8% vs 0.9%), and poorer stroke recovery at 30 days.
Conclusions:
- DW-MRI detected brain infarctions, including their number, size, and total volume, are significantly associated with clinical ischemic strokes, disabling strokes, and worse recovery after TAVR.
- These DW-MRI metrics may serve as valuable surrogate outcomes in clinical trials focused on stroke prevention during TAVR procedures.
