As I’ve wondered many times before – given the theoretical narrow therapeutic window for tPA in stroke, paired with the heterogenous patient substrate and disease process – why do we consent all patients similarly? Why do we not provide a more individualized risk/benefit prediction?
Part of the answer is derived from money & politics – there’s no profit in carefully selecting patients for an expensive therapy. Another part of the answer is the reliability of the evidence base. And, finally, the last part of the answer is the knowledge translation bit – how can physicians be expected to perform complex multivariate risk-stratification and communicate such information to a layperson in the acute setting?
In this paper, these authors describe the development process of an iPad application specifically designed for pictoral display of individualized risk/benefit for tPA administration in acute ischemic stroke. Based on time from onset to treatment, age, gender, medical history, NIHSS, weight, and blood pressure, manual entry of these variables into the software provides individualized information regarding outcomes given treatment or non-treatment.
Unfortunately, the prediction instrument – S-TIPI – is based on: NINDS, ECASS II, and ATLANTIS. Thus, as you might expect, in the most commonly used time frame of 0-3 hours, the outcomes essentially approximate NINDS. The authors mention they used the UK portion of the Safe Implementation of Thrombolysis in Stroke database and the Virtual International Stroke Trials Archive to refine their calculations, but do not delve into a discussion of predictive accuracy. Of note, a previous article describing recalibration of S-TIPI indicated an AUC for prediction of only 0.754 to 0.766 – but no such uncertainty, nor their narrowly derived limited data set, are described in this paper.
Regardless, such “precision medicine” decision instruments – for both this and other applications – are of great importance in guiding complex decision-making. This paper is basically a “check out what we made” piece of literature by a group of authors who will sell you the end result as a product, but it is still an important effort from which to recognize and build.
“Development of a computerised decision aid for thrombolysis in acute stroke care”
http://www.ncbi.nlm.nih.gov/pubmed/25889696