Blood pressure management in ischemic stroke

I have been on conferences and other meetings the last two weeks, which is why I didn’t write anything.

Back on track, we go back to the roots of a proper stroke physician: blood pressure management. We discuss the physiology and pathophysiology of autoregulation and it’s impairment in the penumbra of a stroke (regardless of whether it is small – a lacune – or big – an embolic stroke, there is always an area of tissue at risk around the stroke core). Depending on the time and place you measure it, brain tissue might like more or less of blood (flow or pressure); if it is not enough, ischemia develops, otherwise the breakthrough edema happens (as in RPLS aka PRES). If the local tissue pressure is too high (e.g. through edema), perfusion pressure needs to be higher than in areas where no pressure has developed.

All in all, you never know the distribution of pathophysiological processes and therefore you can never know the best blood pressure for your stroke. Now, if recanalization happens this doesn’t really matter much as the penumbra (hopefully) shrinks to nil, which is why this should be our primary goal. Otherwise or on the way to recanalization we compromise:

  • Don’t change blood pressure – you never know where it should be.
  • In extreme cases (> 220/110 mmHg) you are allowed to lower the blood pressure carefully (slowly) about – say – 20%
  • rtPA/recanalization: if you thrombolyse or try to mechanically recanalize, reduce RR to below 160 (as a goal, which means you arrive at 180 proper) to prepare for the time of recanalization (which you can never pinpoint)
  • After recanalization: breakthrough edema is dangerous, reduce RR to below 140 (as in post-CEA or post-stent)
  • If the acute phase is over (no tissue at risk left): wait for the natural fall of RR (roughly 7-10d)
  • Then (ambulatory care!) aim at < 140/90 mmHg; no particular preference for any substance class
  • For systolic hypertension w/o AI try thiazides.
  • For labile and office hypertension try Ca-antagonists

References

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