Key Points:
- Tool developed to identify good candidates for endovascular stroke therapy
- Highly predictive of positive outcome after successful recanalization in patients with large vessel occlusion
A new scoring system is showing promise at selecting which stroke patients with large vessel occlusion are best suited to endovascular therapy, reports a paper published online October 15, 2014 ahead of print in the Journal of Neurointerventional Surgery.
The Pittsburgh Response to Endovascular therapy (PRE) score can be calculated at patients’ bedside and could prove useful in both clinical and research settings, researchers said.
Investigators led by Tudor G Jovin, MD, of the University of Pittsburgh Medical Center (Pittsburgh, PA), used logistic regression analysis to identify predictors of good outcomes, defined as 90-day modified Rankin scale score (mRS) of 0–2, in a derivation cohort of 247 consecutive patients with anterior circulation large vessel occlusions who were treated at Grady Memorial Hospital (Atlanta, GA).
The resulting independent predictors—age, baseline National Institute of Health Stroke Scale (NIHSS) score, and Alberta Stroke Program Early CT Score (ASPECTS)—all were adopted as elements of the PRE score.
The score was found to be highly predictive of good outcomes in the derivation cohort as well as in 2 validation cohorts of patients at University of Pittsburgh Medical Center (n = 393) and Unitatd’Ictus Vall d’Hebron (n = 204). Area under the curve (AUC) values were 0.79, 0.79, and 0.72, respectively.
When compared to other validated tools, PRE score outperformed both the Totaled Health Risks In Vascular Events (THRIVE, P = 0.03) and Stroke Prognostication using Age and NIHSS (SPAN, P = 0.007) scores, with a trend towards superiority to the Houston Intra-Arterial Therapy 2 (HIAT2, P = 0.06) and iSCORE (P = 0.051) for predicting good outcomes.
Algorithm for Using Score
The authors suggest an algorithm in which the PRE score could be used to select patients for endovascular intervention: among patients with large vessel occlusion of the internal carotid artery or the M1 or M2 middle cerebral artery within 8 hours of symptom onset, successful recanalization would only be likely to improve outcomes if their PRE score is between -24 and 49.
“It is imperative to ensure that [endovascular stroke therapy] is offered only to patients who are likely to benefit, while avoiding unnecessary interventions in patients who are either ‘too good’ or ‘too bad’ to treat,” write the authors, noting that while several scores have been developed for this use, few are actually being applied in practice. They describe the PRE score as a “simple tool that can be used at bedside” for patient selection.
Broad Adoption Possible
“With the recent evidence establishing [intra-arterial] therapy for [large vessel occlusion] stroke and the importance of patient selection using imaging/clinical measures, tools such as these could help establish uniform patient selection strategies across many centers,” Brijesh P. Mehta, MD, of Memorial Healthcare System (Hollywood, FL), told WLNCMD in an email.
Advantages of the PRE score include its ease of use, intuitiveness, and use of continuous variables rather than arbitrary cut-off points, Mehta said. Its disadvantages include the subjectivity of the ASPECTS score, use of the dichotomized mRS as an outcome measure (which is falling out of favor in the stroke community), and lack of inclusions of important variables such as pre-stroke baseline status, cognitive status, and medical comorbidities/frailty.
With further validation, the PRE score could come into widespread use, Mehta predicted. “At the time this study was performed, perfusion imaging was still being evaluated in clinical trials for [intra-arterial] therapy for stroke. Now we know that perfusion imaging is very valuable. Perhaps improving the score with perfusion imaging data rather than ASPECTS could improve its applicability.”
Source:
Rangaraju S, Aghaebrahim A, Streib C, et al. Pittsburgh Response to Endovascular therapy (PRE) score: optimizing patient selection for endovascular therapy for large vessel occlusion strokes. J NeuroIntervent Surg. 2015;Epub ahead of print.
Disclosures:
- Mehta reports no relevant conflicts of interest.
