Thrombolytic Treatment for Ischaemic Stroke: Could the Crisis of Confidence Have Been Avoided by Better Analysis of Trial Data?

Abstract

In many countries, thrombolysis with intravenous alteplase has become a central part of acute stroke care in recent years, requiring radical restructuring of services. However, a significant minority of emergency and stroke physicians have always had serious doubts about the safety and efficacy of thrombolytic treatment, and in 2015 these prompted a major review of the licensing status of alteplase by the UK regulatory authorities. Subsequent dramatic headlines and media stories have called into question the integrity of researchers and clinicians and undermined public faith in medical research. How did this situation arise and what should be done to prevent a repetition as we enter the era of intra-arterial treatment for stroke?Early intravenous alteplase increases the chances both of good recovery and of severe haemorrhage, so the risk/benefit balance must be assessed for individual patients according to stroke severity. For older patients and those with bigger strokes, the 'good recovery' criterion is an inefficient way of assessing treatment effects since few achieve full independence and differences between levels of functional impairment are ignored. This waste of information can be reduced by applying different criteria for 'good' and 'poor' outcomes in different prognostic groups (as clinicians do intuitively), hence increasing the number of patients contributing useful data. Such 'three-way prognosis-based outcome' analysis of existing and future trials could greatly increase the amount of relevant evidence to guide clinical decisions for individual patients across the range of stroke severity.