What is the latest in stroke treatment?
Unfortunately,
the latest doesnt always mean the greatest.
Media
reports are filled with the latest news about medical advances. Such
reports often focus on early, preliminary research that shows great promise.
Yet, many promising therapies founder on the rocks of reality. Contrary
to what one might infer from the almost daily reports of medical breakthroughs,
progress in medical science does not trace a continually rising curve.
It follows a trajectory that is more like the graph of a bull market,
generally upward, but marked by many advances and retreats. Popular medical
news tends to focus on what is new and encouraging. Only the most dramatic
of setbacks receive wide publicity. For this article, I will highlight
four broad trends that seem likely to be of enduring value, rather than
give a report on the latest up ticks in medical science.
Focused
Acute Treatment
Stroke
is local process. A stroke affects only a certain part of the brain.
It is typically caused by a problem in only a certain part of a blood
vessel. The only currently approved medication for an acute stroke is
TPA, a clot dissolving agent. Although TPA is clearly useful in the proper
circumstances, it is both less effective and more dangerous than we would
like. In general, it gives about 12% more excellent outcomes, but causes
harmful bleeding about 6% of the time.
Part of the reason for this less-than-optimal performance may be that
the medication is given intravenously, a route that may dilute its effectiveness
in dissolving a stroke-causing clot, while simultaneously increasing
its risk by interfering with beneficial clots that keep us from bleeding.
By delivering treatment through intra vascular catheters, skilled interventionalists
are able to focus treatment much more clearly on the problem vessel.
Focused treatment, via catheters or other means, will likely prove more
effective than treatment that is dispersed throughout the body.
Extending
the Effectiveness of Acute Treatment
Once blood flow is cut off to a part of the brain, a stroke begins, but
a stroke doesnt happen all at once. It is a process that evolves
over hours and days. Reopening the blocked artery is an important technique
for reversing or limiting the effect of a stroke, but it must be done
quickly usually within three hours, if it is to be helpful. The
search is on for agents and techniques that will widen the window of
opportunity to effectively use the reopening strategy. Such treatments
should also help to inhibit the vicious cycle of biochemical events that
may lead to tissue death, even after reopening is successful.
Despite many trials, we have not yet found a treatment that clearly meets
this need, but we have come close on several occasions. I believe it
is only a matter of time before a proven neuroprotective
agent becomes available.
The
Science of Stroke Rehabilitation
Functionally, the brain has long been a black box. We could control inputs
and measure outputs, but how the former changed into the latter was largely
hidden from view. With the advent of advanced imaging tools that allow
us to see how the brain reorganizes from a stroke, all of that has changed.
With a better understanding of functional deficits at a tissue level,
we can expect to see more appropriately tailored and more effective rehabilitation.
Until recently stroke rehabilitation was much more of an art than a science.
Now the science of randomized controlled trials is changing rehabilitation,
just as it has changed acute treatment. Proven and evidence-based treatment
such as constraint induced movement therapy will become increasingly
common.
Systematic
Quality Improvement
In stroke as in other areas of medicine, it has long been recognized
that there is a gap between the things that we know to be beneficial
and the things that we routinely accomplish in common practice. The reasons
for this gap are multiple, but they could be summarized as failings of
our system of stroke care.
Systems of care, like other complex dynamic systems, are not easy to
program. A little tinkering on the front end can sometimes lead to large,
negative, unintended consequences on the back end. It is probably from
experience with systems of this sort that certain aphorisms were born:
If it aint broke dont fix it, and the
road to hell is paved with good intentions.
With the widespread availability of computerized data tracking and analysis,
it is becoming possible to see in real time how adjustments to the system
affect the systems performance. With this sort of feedback, institutions
and providers are becoming more confident in their ability to tune their
systems on the fly, without driving the entire endeavor into the ditch.
Continuous
quality improvement is finally becoming a reality, not just a slogan.