Acute Ischemic Stroke Treatment, Part 2: Treatment “Roles of Capillary Index Score, Revascularization and Time”

More bloviating and talking about what they don't know. You're fucking screwed if you have a stroke right now. The authors need to read up on the neuronal cascade of death. They wouldn't be allowed to receive any funding from my organization with that lack of knowledge.
http://journal.frontiersin.org/article/10.3389/fneur.2015.00117/full?

Firas Al-Ali¹*, John J. Elias² and Danielle E. Filipkowski²

• ¹Department of Neuro Interventional Surgery, Akron General Medical Center, Akron, OH, USA
• ²Department of Research, Akron General Medical Center, Akron, OH, USA

Due to recent results from clinical intra-arterial treatment for acute ischemic stroke (IAT-AIS) trials such as the interventional management of stroke III, IAT-AIS and the merit of revascularization have been contested. Even though intra-arterial treatment (IAT) has been shown to improve revascularization rates, a corresponding increase in good outcomes has only recently been noted. Even though a significant percentage of patients achieve good revascularization in a timely manner, results do not translate into good clinical outcomes (GCOs). Based on a review of the literature, the authors suspect limited GCOs following timely and successful revascularization are due to poor patient selection(wrong, wrong, wrong) that led to futile and possibly even harmful revascularization. The capillary index score (CIS) is a simple angiography-based scale that can potentially be used to improve patient selection to prevent revascularization being performed on patients who are unlikely to benefit from treatment. The CIS characterizes presence of capillary blush related to collateral flow as a marker of residual viable tissue, with absence of blush indicating the tissue is no longer viable due to ischemia. By only selecting patients with a favorable CIS for IAT, the rate of GCOs should consistently approach 80–90%. Current methods of patient selection are primarily dependent on time from ischemia. Time from cerebral ischemia to irreversible tissue damage seems to vary from patient to patient; so focusing on viable tissue based on the CIS rather than relying on an artificial time window seems to be a more appropriate approach to patient selection.

Introduction

The interventional management of stroke (IMS) III trial (1) showed non-superiority of intra-arterial (IA) revascularization combined with intra venous (IV) tissue plasminogen activator (tPA) treatment over IV tPA alone, and the systemic thrombolysis for acute ischemic stroke (SYNTHESIS) trial demonstrated similar lack of favorable clinical outcomes for IA versus IV tPA therapy (2). This is despite the high revascularization rate in the IA arms in these trials. The role of intra-arterial treatment for acute ischemic stroke (IAT-AIS) has been contested. Paradoxically, however, the benefit of revascularization to clinical outcomes is convincingly attested to in prior literature. In a recent meta-analysis of 998 patients with clinical follow-up at 3 months, good clinical outcome was found in 58% of revascularized patients as compared to 24.8% in non-revascularized patients (3). When revascularization occurred within the first 6 h, good clinical outcomes (GCOs) were found in 50.9% of revascularized patients as compared to 11.1% in non-revascularized patients. Other authors reached similar conclusions. Even in the IMS III trial, better revascularization using the modified thrombolysis in cerebral infarction (mTICI) score led to better outcomes than those for patients who achieved lesser revascularization (1). This data were recently resolved with the publication of newer trials. In MR CLEAN, EXTEND-IA, and ESCAPE, good recanalization rates were achieved in 58.7, 86, and 72.4% of patients, respectively, with accompanying GCO rates at 32.6, 71, and 53%, respectively (4–6). While these results demonstrate IA superiority with higher recanalization rates than with IVT, there are still a significant number of patients who achieved good and timely revascularization that did not also achieve GCOs. So if better revascularization improves outcome and IA treatment has a better revascularization rate than IV treatment, how can we explain the lack of GCOs in some of these patients?

Revascularization and Outcome

Revascularization is defined as the restoration of anterograde blood flow to the ischemic area through the recently occluded artery. Currently, this is reported using the mTICI score, with mTICI of 2b or 3 being considered successful revascularization (7). The aim of revascularization is to produce clinical improvement through restoring the cerebral blood flow (CBF) level to greater than the critical threshold of 23 ml/100 g/min of viable brain tissue (8). This should translate into a permanent resolution of AIS symptoms by saving the ischemic tissue before it progresses to irreversible damage. So if perfect revascularization is achieved (mTICI = 3) in a timely manner, i.e., before ischemia becomes irreversible, clinical improvement should be achieved for almost all patients, as well as for the majority of patients with less effective revascularization (mTICI = 2b). However, review of the literature reveals that only around 50% of patients in whom we obtained timely recanalization (mTICI 2b, 3) will achieve a good clinical outcome (Table 1) (1, 2, 9–13). Attempting to solve the paradox regarding why all technically successful revascularizations do not translate into GCOs should help us improve our revascularization strategy.

more at link.