Kat Dakay, DO

Schönenberger S, Uhlmann L, Ungerer M, Pfaff J, Nagel S, Klose C, et al. Association of Blood Pressure With Short- and Long-Term Functional Outcome After Stroke Thrombectomy: Post Hoc Analysis of the SIESTA Trial. Stroke. 2018

Now that mechanical thrombectomy for acute ischemic stroke has become a well-established treatment, the focus has become how best to manage patients peri-intervention.

As the authors mentioned, two major questions keep arising: What mode of sedation is best for patients undergoing thrombectomy? And, what is the ideal blood pressure goal to maintain before, during, and after intervention?

On the one hand, hypotension in the acute phase of stroke could theoretically lead to hypo-perfusion of the ischemic penumbra, leading to expansion of infarct. On the other hand, it is known that hypertension can increase the risk of intracerebral hemorrhage in patients who receive IV tPA [1], and it is unclear if this could translate to endovascular reperfusion as well. The optimal blood pressure for patients peri-intervention is not known.

The SIESTA trial, a single-center randomized trial, randomized 150 patients with a large vessel occlusion in the anterior circulation to either conscious sedation versus generalized anesthesia. The primary outcome was neurologic improvement at 24 hours, and the trial demonstrated that there was no difference in early neurologic improvement between the generalized anesthesia and conscious sedation groups [2]. The main findings were published in October 2016 in JAMA.

A post-hoc analysis of the SIESTA trial [3] sought to address the second question of optimal blood pressure. The SIESTA trial set a blood pressure goal of SBP 140-160 in all patients, and recorded values at baseline, pre-intervention, pre-recanalization, and post-intervention. TICI 2b or 3 reperfusion was achieved in 89% of the GA patients and 80.5 % of the CS patients. There was no association between SBP or DBP change and NIHSS change after 24 hours, including no measurable long-term detriment from drops in blood pressure in the peri-interventional phase. Overall, 112 of the 150 patients required norepinephrine to maintain the systolic blood pressure above 140 mmHg. However, there was an association between doses administered of propofol, ramifentanil, and norepinephrine and a decreased improvement in the 24-hr NIHSS.

This study is important because it suggests that blood pressure drops due to sedation or GA, when corrected expeditiously with vasopressors to reach a target goal of 140 mmHg systolic, does not affect the long-term outcome. Prior studies had been conflicting. A retrospective study from 2015 had noted an association between lower blood pressures intraprocedurally and good outcome [4], but was limited in that information regarding administration of antihypertensives was not collected, and no clear targets were specified in the paper. However, a subgroup analysis of MR-CLEAN had shown that decreases of 10 mm Hg or more in MAP while undergoing intervention was associated with worse outcome — although, unlike SIESTA, there were no specified targeted blood pressure goals [5].

The results from the SIESTA post-hoc analysis seem to suggest that brief drops in blood pressure are not deleterious to outcome, when taken in the context of an overall target blood pressure goal of 140-180 mmHg systolic. This was achieved with judicious use of vasopressors, when necessary. It does not necessarily suggest that there is no effect of blood pressure on functional outcome, or to justify allowing wide shifts in blood pressure without corrective measures.

One limitation of the study is that the blood pressure goal administered in SIESTA does not take into account final recanalization status, although the majority of the patients (89% in the GA group and 80.5% of the CS group) had technically successful recanalization — if a patient undergoes intervention but no or partial recanalization is achieved, should they have a higher blood pressure goal? Further studies to address these questions would be helpful in tailoring blood pressure targets to the individual patient.

References:

  1. Larrue V, von Kummer RR, Muller A, Bluhmki E. Risk factors for severe hemorrhagic transformation in ischemic stroke patients treated with recombinant tissue plasminogen activator: A secondary analysis of the european-australasian acute stroke study (ecass ii). Stroke. 2001;32:438-441
  2. Schonenberger S, Uhlmann L, Hacke W, Schieber S, Mundiyanapurath S, Purrucker JC, et al. Effect of conscious sedation vs general anesthesia on early neurological improvement among patients with ischemic stroke undergoing endovascular thrombectomy: A randomized clinical trial. JAMA. 2016;316:1986-1996
  3. Schonenberger S, Uhlmann L, Ungerer M, Pfaff J, Nagel S, Klose C, et al. Association of blood pressure with short- and long-term functional outcome after stroke thrombectomy: Post hoc analysis of the siesta trial. Stroke. 2018;49:1451-1456
  4. John S, Hazaa W, Uchino K, Toth G, Bain M, Thebo U, et al. Lower intraprocedural systolic blood pressure predicts good outcome in patients undergoing endovascular therapy for acute ischemic stroke. Interv Neurol. 2016;4:151-157
  5. Treurniet KM, Berkhemer OA, Immink RV, Lingsma HF, Ward-van der Stam VMC, Hollmann MW, et al. A decrease in blood pressure is associated with unfavorable outcome in patients undergoing thrombectomy under general anesthesia. J Neurointerv Surg. 2018;10:107-111