Agreement with evidence for tissue Plasminogen Activator use among emergency physicians: a cross-sectional survey

Even when allowing for the low response rate, study findings suggest a sizeable minority
of Australian emergency physician fellows and trainees do not agree with statements
supporting use of tPA in the treatment of acute stroke. Consideration of the participating
physician and workplace characteristics may suggest that physicians from tertiary
hospitals may be over-represented here, therefore, it is likely the majority of results
apply to this sub-group.

Physician agreement with evidence for tPA

As emergency physicians are often the first contact for the in-hospital care of stroke
patients, their attitudes towards tPA are a critical factor in the use and non-use
of this treatment. Emergency physicians help shape treatment protocols and as such,
their perceptions influence the attitudes of others 16]. Given the utility of tPA in significantly reducing disability associated with stroke
5], it is interesting that less than half (39.6%) of respondents agreed that appropriate
use of tPA will improve the odds of independent survival for stroke patients.

Only a small proportion of participants agreed the evidence underpinning tPA use is
strong when administered within 4.5 h of stroke onset (16.8%), and that the evidence
is strong enough to warrant use (37.4%). This is despite approval from the Australian
Therapeutic Goods Administration for tPA use, and recommendations in the current Australian
clinical practice guidelines 5]. Use of tPA is also approved up to 4.5 h post-stroke onset in the UK by the Medicines
and Healthcare Products Regulatory Agency, and recommended up to 4.5 h by AHA and
ASA 15]. These results may be indicative of the influence of authoritative emergency-specific
bodies that openly do not support the use of tPA by emergency physicians.

Previous studies have identified limited acceptance of the evidence for tPA use in
acute stroke 17]. Scott’s study of emergency physicians in the US found 49% agreed the science regarding
the use of tPA in stroke is convincing 11]. Additionally, Wang reported 72% of responders recognised tPA is the preferred treatment
for acute stroke, and 59% were aware of the limited time-window for administration
16]. While Wang’s outcomes may be biased due to the sampling procedure employed, and
the inclusion of residents within family practice, internal medicine and neurology
16], these results highlight a lack of awareness regarding clinical practice guidelines
for tPA use in acute stroke care.

Almost half of the respondents in our survey did not agree with any statements supporting
tPA use in acute stroke, with only 20% of the respondents having “High agreement”
with the literature. In order for tPA treatment to become widely accepted and adopted
in emergency settings that have the necessary facilities, beliefs and attitudes towards
treatment need to be in accordance with best-practice recommendations.

Reasons behind physician views of tPA

Research appears to be the key feature influencing attitudes of tPA. A high proportion
of respondents reported ‘additional clinical trials of tPA’ (83.8%), and ‘research
conducted by emergency department staff’ (60.3%) would influence their views. Indeed,
there have been calls for additional clinical trials of tPA treatment to be conducted
18], leading to re-analysis of the National Institute of Neurological Disorders and Stroke
trial data 19], and the spread of uncertainty towards use of this therapy 20]. However, given the existing evidence-practice gap, serious consideration about whether
additional trials of tPA will actually shift attitudes and practice surrounding the
use of tPA, is crucial in determining the next steps forward for the implementation
of this therapy. While Scott’s trial targeting hospital staff failed to produce a
significant increase in use of tPA for stroke, the authors recognise that additional
strategies to increase treatment are required 21].

Factors associated with agreement with evidence for tPA

Respondents were nearly four times more likely to have high agreement with the evidence
supporting tPA use in acute stroke if they perceived their head of ED administers
tPA treatment to eligible patients. This result is supported by the 43.8% of respondents
who indicated guidance from a professional colleague would influence their views on
the use of tPA. While no other studies have examined this relationship, one study
found the presence of “uncompromising, individual clinical leadership” in a hospital
setting was significantly associated with the likelihood of receiving tPA 22]. Results are indicative of the power of social influence and modelling in changing
health providers’ attitudes and behaviour 23]. Social influences play an important role in the implementation of new behaviours,
and by targeting provider knowledge, attitudes and social norms, opinion leaders can
aid adoption of new practices 24]. Demonstrating or modelling new skills, can build both skill and confidence to perform
a desired behaviour 25]. Local opinion leaders in hospital settings can also be effective in promoting evidence-based
practice 23].