Yoon Y, Lee DH, Kang DW, Kwon SU, and Kim JS. Single Subcortical Infarction and Atherosclerotic Plaques in the Middle Cerebral Artery: High-Resolution Magnetic Resonance Imaging Findings. Stroke. 2013
Subcortical stroke is often erroneously equated to lacunar stroke with similar pathophysiology. It is perhaps more accurate to use subcortical stroke as an entity that encompass two disease mechanisms – small perforating artery infarcts caused by native vessel lipohyalinosis/atherosclerosis, and infarction associated with parental artery disease. Given the distinction, it is important to study their differences to aid the understanding of potential distinguishable clinical characteristics that could impact treatment strategies.
In this interesting study by Yoon et. al, the authors classified single subcortical infarctions (SSI) in the MCA territory into proximal SSI (pSSI) or distal SSI (dSSI) by their radiological appearance on MRI. pSSI extends to the surface of the MCA whereas dSSI does not. They enrolled 39 patients in total, half with pSSI and the other half with dSSI. Patients with pSSI had more number of large infarcts with higher NIHSS but less microbleeds compared to patients with dSSI. Using high resolution MRI (3T), main trunk MCA plaques were detected in 20 patients. In terms of plaque location, superiorly located plaques were more frequently seen in pSSI patients, which the authors speculate could be important in determining the type of SSI.
It must be noted that this study is too small to make any general conclusions about the clinical characteristics of subcortical strokes. Moreover, the high resolution MRI protocol only assessed the main trunk of MCA, so M2 branches and distal MCA vessels are not accounted for. This speaks to the need for more sensitive and accurate radiological methods in the future in studying the cerebrovasculature.
Kharitonova T, Melo TP, Andersen G, Egido JA, Castillo J, Wahlgren N. Importance of cerebral artery recanalization in stroke patients with and without neurological improvement after intravenous thrombolysis. Stroke. 2013
Kharitonova et al. conducted a studyto evaluate the association of restoration of blood flow and early neurologic improvement (NI) after inyravenous thrombolysis (IVT) on 3-month outcome. This is an important question because many stroke centers are adopting protocols that use recanalization status after IVT to identify patients for rescue reperfusion intervention.
Patients in this retrospective study were enrolled in the Safe Implementation of Treatment in Stroke International Stroke Thrombolysis Register (SITS-ISTR). All 5324 patients had documented baseline vessel occlusion and follow-up vessel imaging 22-36h after IVT. Patients with NI and vessel recanalization were more likely to be independent at 3 months than patients with persistent occlusion despite NI and and those without NI despite recanalization (OR 15.9; 95% CI 12.5-20.0 vs. OR 4.7; 95% CI 3.6-6.1 and OR 2.7; 95% CI 2.2 -3.3, respectively).
In short, recanalization of an occluded artery in an acute stroke setting was associated with favorable functional outcome regardless of rapid NI after IVT. This concludes that recanalization with rescue therapy should be considered in patients with persisting occlusion after thrombolysis even after significant neurological improvement.
Boehme AK, Kapoor N, Albright KC, Lyerly MJ, Rawal PV, Shahripour RB. Systemic Inflammatory Response Syndrome in Tissue-Type Plasminogen Activator–Treated Patients is Associated With Worse Short-termFunctional Outcome. Stroke. 2013
Research has shown that successful thrombolytic therapy with tPA attenuates Systemic Inflammatory Response Syndrome (SIRS) in acute stroke patients. The primary goal of this retrospective study was to determine if patients who received IV tPA and developed SIRS had a difference in functional outcomes compared to those who did not. These patients included those without diagnosed infection who had two of the following criteria: temperature <36 or >38 degrees, HR>90, RR>20, WBC <4000 or >12000/mm. Eighteen percent of patients were found to have SIRS, around 1 in 5, and it was a predictor of poor functional outcome at discharge, even after adjusting for confounders such as NIHSS, age, race and prior stroke. Interestingly, Black patients and those with lower total cholesterol at baseline were more likely to have SIRS.
This study has an interesting result in that, despite adjusting for the known factors contributing to poor outcome in acute ischemic stroke patients, SIRS stands out as an independent predictor. One theory is that despite receiving thrombolysis, which may or may not have ultimately been “successful”, the individual components constituting SIRS have a detrimental effect on functional outcomes. However, future studies should measure inflammatory markers in patients labeled with SIRS and then correlate those levels with outcomes. The ultimate goal, of course, is to identify these patients early to try and abate poor functional outcomes.
van Delden AEQ, Peper CE, Nienhuys KN, Zijp NI, Beek PJ, and Kwakkel G. Unilateral Versus Bilateral Upper Limb Training After Stroke: The UpperLimb Training After Stroke Clinical Trial. Stroke. 2013
They randomized 60 patients who were 1-6 months after their stroke into the three treatment arms treated for six weeks for 3 hours a week (60minute sessions, 3 times a week) and encouraged to do exercises at home. The results showed no demonstrably different outcomes in arm paresis after the intervention period using a standardized assessment tool Action Research Arm Test (ARAT).
While much has said about constraint induced movement therapy, few randomized studies have sought out to answer this specific question. I’m glad to see there is work in the stroke rehab community to evaluate the effectiveness of certain therapies compared with others. For now, I will still recommend my patients to seek as much rehab and exercise as they will tolerate, as only maximal effort and maximal time has demonstrated results.
de Man-van Ginkel JM, Hafsteinsdóttir TB, Lindeman E, Ettema RGA, Grobbee DE, and Schuurmans MJ. In-Hospital Risk Prediction for Post -stroke Depression: Developmentand Validation of the Post-stroke Depression Prediction Scale. Stroke. 2013
ystolic Blood Pressure During Acute Stroke is Associated With Functional Status and Long-term Mortality in the Elderly. Stroke. 2013
“Let the blood pressure rise”…might be a frequent say among specialists treating patients with an acute stroke. The AHA guidelines for treatment of acute stroke advices caution on treating high blood pressure in this setting. Some clinical trials and observational studies have even suggested that a rapid decline or aggressive lowering of blood pressure might be associated with worse outcomes. In this issue of Stroke, Grossman et al. present data in regards to predictors of short and long term functional status and mortality in an elderly population with acute stroke that challenges the notion that high blood pressure might be protective in the acute stroke context.
The investigators recruited 177 patients > 70 years old with acute stroke and hypertension (excluding those with DBP/SBP > 120/220). They obtained baseline characteristics, mRs at 7 days and mortality at 5 years. Two key features of this study are original: the continuous blood pressure measurement over the first 24 hrs of the stroke and the long term follow. The investigators found that in the short term; average continuously-measured SBP > 160 (compared to manually obtain) predicted a worse outcome, and average SBP > 160 conferred greater odds of mortality compared to those with SBP < 160 after adjusting for covariates included in the model. Although this study doesn’t answer whether blood pressure should be let to freely rise in the setting of acute stroke or if it should be maintained within certain parameters, it brings up some additional interesting questions. For example, is elevated SBP in this elderly population an indicator of stroke severity or could it represent a marker of more advanced cardiovascular disease? Are the effects of increased SBP on functional outcome and mortality the same across different stroke mechanisms? what could be the mechanisms explaining the worse outcome 7 days after the index event vs. the 5-year mortality increment?
As the authors suggest, perhaps ASCOD grading would be more useful for studying genetics of stroke where overlap in contributing conditions maybe more important. Similarly, this classification scheme may be helpful in finding patients who may benefit from therapeutic trials who may otherwise be missed when using TOAST criteria.
Association of Chronic Kidney Disease With Cerebral Microbleeds in Patients With Primary Intracerebral Hemorrhage. Stroke. 2013