Advances in critical care and emergency medicine 2007

Antihypertensive Treatment of Acute Cerebral Hemorrhage (ATACH) II: design, methods, and rationale

The December 2003 report from the National Institute of Neurological Disorders and Stroke (NINDS) Workshop on priorities for clinical research in intracerebral hemorrhage (ICH) recommended clinical trials for evaluation of blood pressure management in acute ICH as a leading priority. The Special Writing Group of the Stroke Council of the American Heart Association in 1999 and 2007 emphasized the need for clinical trials to ensure evidence-based treatment of acute hypertensive response in ICH. To address important gaps in knowledge, we conducted a pilot study funded by the NINDS, Antihypertensive Treatment of Acute Cerebral Hemorrhage (ATACH) I Trial, during 2004-2008 to determine the appropriate level of systolic blood pressure (SBP) reduction. We now have initiated a multi-center, randomized Phase III trial, the ATACH II Trial, to definitively determine the efficacy of early, intensive, antihypertensive treatment using intravenous (IV) nicardipine initiated within 3 h of onset of ICH and continued for the next 24 h in subjects with spontaneous supratentorial ICH. The primary hypothesis of this large (N = 1,280), streamlined, and focused trial is that SBP reduction to ≤140 mm Hg reduces the likelihood of death or disability at 3 months after ICH, defined by modified Rankin scale score of 4-6, by at least 10% absolute compared to standard SBP reduction to ≤180 mm Hg. The ATACH II trial is a natural extension of numerous case series, the subsequent ATACH I pilot trial, and a preliminary, randomized, and controlled trial in this patient population funded by the Australian National Health and Medical Research Council. Both trials recently confirmed the safety and tolerability of both the regimen and goals of antihypertensive treatment in acutely hypertensive patients with ICH, as proposed in the present trial. The underlying mechanism for this expected beneficial effect of intensive treatment is presumably mediated through reduction of the rate and magnitude of hematoma expansion observed in approximately 73% of the patients with acute ICH. The Australian trial provided preliminary evidence of attenuation of hematoma expansion with intensive SBP reduction. The ATACH II trial will have important public health implications by providing evidence of, or lack thereof, regarding the efficacy and safety of acute antihypertensive treatment in subjects with ICH. This treatment represents a strategy that can be made widely available without the need for specialized equipment and personnel, and therefore, can make a major impact upon clinical practice for treating patients with ICH.

Patient outcomes in historical comparators compared with randomised-controlled trials

BACKGROUND

Decompressive hemicraniectomy for malignant middle cerebral artery infarction has long been controversial. Recently, data from randomised-controlled trials have shown that the procedure is life-saving and improves outcome. However, these randomised-controlled trials were difficult to conduct, because of ethical considerations due to high mortality in control groups. While the use of historical comparators may not be ideal for phase III efficacy trials, these data may be useful to inform the selection of trial populations. We sought to replicate the findings of the DESTINY trial of decompressive surgery in malignant middle cerebral artery infarction using the Virtual International Stroke Trials Archive, to determine whether historical comparators could be used as an alternative to control groups in situations where randomised-controlled trials are infeasible or regarded as unethical due to the high mortality under conservative treatment.

METHODS

We extracted data on patients from Virtual International Stroke Trials Archive who displayed signs of malignant middle cerebral artery infarction (baseline National Institutes of Health Stroke Scale> or =20, LOC1A score of > or =1 on the National Institutes of Health Stroke Scale at baseline, lesion volume > or =145 cm(3)). We used a chi(2)-test and logistic regression (adjusting for baseline National Institutes of Health Stroke Scale) to compare the functional outcomes (modified Rankin scores and Barthel index) at the last available follow-up assessment between the DESTINY surgical and the Virtual International Stroke Trials Archive comparator groups. We assessed 90-day survival rates using a Kaplan-Meier analysis and Cox proportional hazards modelling (adjusting for the baseline National Institutes of Health Stroke Scale score).

RESULTS

Fewer patients in the Virtual International Stroke Trials Archive comparator group (n=6/32, 19% with a 90-day follow-up) achieved a good functional outcome by mRS at the final follow-up, when compared with the DESTINY surgical group (n=8/17, 47% with a 6-month follow-up; chi(2)-test, P=0.04). This difference persisted after adjusting for baseline National Institutes of Health Stroke Scale (logistic regression, P=0.04), but not when accounting for patient age (P=0.66). Analysis of Barthel index at the final follow-up revealed no significant difference between the two groups (chi(2)-test, P=0.07), although a trend towards a better outcome in the DESTINY group was observed. In contrast with the findings of the DESTINY trial, we found no significant difference in 90-day survival rates between the surgical (88%) and the Virtual International Stroke Trials Archive (72%) comparator groups (Cox proportional hazards model, P=0.24).

CONCLUSION

The beneficial effects of decompressive hemicraniectomy on survival were not confirmed using a historical comparator dataset. Our observations might be due to the fact that patients with malignant middle cerebral artery infarction are usually excluded from clinical trials of drug efficacy, and patients identified from Virtual International Stroke Trials Archive may not have been truly representative of patients with malignant middle cerebral artery infarction. This mismatch could be rectified through recruitment of population-based studies and stroke registries to Virtual International Stroke Trials Archive to increase the number of patients eligible for entry into the comparator patient data pool.

Sonothrombolysis: an emerging modality for the management of stroke

OBJECTIVE

Ischemic stroke and intracranial hemorrhage remain a persistent scourge in Western civilization. Therefore, novel therapeutic modalities are desperately needed to expand the current limitations of treatment. Sonothrombolysis possesses the potential to fill this void because it has experienced a dramatic evolution from the time of early conceptualization in the 1960s. This process began in the realm of peripheral and cardiovascular disease and has since progressed to encompass intracranial pathologies. Our purpose is to provide a comprehensive review of the historical progression and existing state of knowledge, including underlying mechanisms as well as evidence for clinical application of ultrasound thrombolysis.

METHODS

Using MEDLINE, in addition to cross-referencing existing publications, a meticulous appraisal of the literature was conducted. Additionally, personal communications were used as appropriate.

RESULTS

This appraisal revealed several different technologies close to broad clinical use. However, fundamental questions remain, especially in regard to transcranial high-intensity focused ultrasound. Currently, the evidence supporting low intensity ultrasound's potential in isolation, without tissue plasminogen, remains uncertain; however, possibilities exist in the form of microbubbles to allow for focal augmentation with minimal systemic consequences. Alternatively, the literature clearly demonstrates, the efficacy of high-intensity focused ultrasound for independent thrombolysis.

CONCLUSION

Sonothrombolysis exists as a promising modality for the noninvasive or minimally invasive management of stroke, both ischemic and hemorrhagic. Further research facilitating clinical application is warranted.