Background and Purpose Thin-section non-contrast CT (NCCT) images can be used to measure hyperdense clot size in acute ischemic stroke (AIS). ICA-terminus or proximal-MCA occlusion; admission thin-slice NCCT (≤2.5mm); and no IV-tPA pre-treatment. For each patient hyperdense clot size was measured and recorded along with additional relevant imaging and medical data. Results Mean age was 70 years and mean time-to-CT was 213 moments. Median baseline NIHSS was 16.5. Occlusions were located in the ICA-terminus (34% [18/53]) Ambrisentan (BSF 208075) MCA M1 (49%[26/53]) and M2 segments (17% [9 of 53]). Hyperdense thrombus was visible in 96% with mean and median clot lengths (mm) of 18.5 (±14.2) and 16.1 (7.6-25.2) respectively. Occlusion location was the strongest predictor of clot size (multivariate p=0.02). Clot size was ≥8mm in 94% 73 and 22% of ICA-terminus M1 and M2 occlusions respectively. Summary The majority of anterior blood circulation proximal occlusions are ≥8mm very long helping to clarify the low published rates of IV-tPA recanalization. ICA-terminus occlusion is an excellent marker for clot size ≥8mm; vessel-imaging status alone may be adequate. Ambrisentan (BSF 208075) Thin-section NCCT appears useful for individuals with MCA occlusion due to the wide variability of clot lengths. (κ =0.91 95 Univariate predictors of ≥8mm-clot were more proximal occlusion level and higher baseline NIHSS score (Table 1). By occlusion level 94 of ICA-T 73 of M1-MCA and 22% of M2-MCA clots were ≥8mm long. In binary logistic regression clot location was the only self-employed predictor of clot ≥8mm (p=0.02; modified OR 6.43 (95%CI: 1.29 to 31.98) per step from M2 to M1 to ICA-T). Conversation This study confirms that at least 90% of anterior Rabbit Polyclonal to CIDEB. blood circulation proximal occlusions are visible as hyperdense clot using thin-section NCCT.4 The vast majority (72%) of these occlusions have extensive (≥8mm) clot burden further suggesting a sizeable population who may potentially benefit from an IV-IAT bridging approach (Number 2). Number 2 56 woman with NIHSS 15 presents 3 hours after onset. Thin-section noncontrast CT data (A) demonstrate a remaining M1 section clot measuring 16.6mm. The occlusion is definitely confirmed on CT angiography (B). The observed recanalization effectiveness of IV-tPA based on clot location may correlate with the likelihood of a clot size greater than 8 mm at that location. For example the proportions of short (<8mm) Ambrisentan (BSF 208075) clots that we found in ICA-T (6%) and M1 (27%) occlusions closely approximate previously reported rates of early IV-tPA recanalization (4.4% for ICA-T and 32.3% for M1).6 Furthermore these findings have important implications for quick patient triage to treatment. Currently many centers wait 30 minutes or longer to assess for IV-tPA failure prior to sending a patient to IAT.7 However this same delay has been associated with a 10% family member reduction in the probability of good outcome.8 Because virtually all ICA-terminus occlusions are ≥8mm long it is reasonable to use CTA-evidence of ICA-terminus occlusion to triage individuals directly to Ambrisentan (BSF 208075) IAT during IV-tPA infusion. This approach is definitely supported by IMS-III which shown a four-times higher rate of good end result after bridging therapy in individuals with CTA-documented ICA-terminus occlusions.2 On the other hand clot size measurement may be critical for triaging proximal MCA occlusions. In IMS-III there was an equivalent rate of good outcome (~50%) between the treatment arms for M1 occlusions.2 By removing the 25-30% of M1 clots which are short and likely to respond to IV-tPA alone individuals who may benefit from catheter-based therapy may be rapidly triaged to the interventional suite. This approach is being tested in the THERAPY randomized trial. ACKNOWLEDGMENTS None FUNDING SOURCES SK received Ambrisentan (BSF 208075) teaching support from Harvard Catalyst by NIH Honor 8UL1TR000170-05. The content is definitely solely the authors’ responsibility and does not necessarily represent the official views of NIH Harvard University or college/Catalyst and its affiliated healthcare centers. Footnotes DISCLOSURES SK SRP and MHL: GE-Healthcare (study support) MHL: GE-stock (<$10K) Millennium-Pharmaceuticals (specialist). MA SPS and Abdominal: Penumbra-Inc employees. LTM and JAH: none. AJY: Penumbra-Inc. (study support) NIH (MR-RESCUE trial) and Remedy Pharmaceuticals-Inc. (study support) Referrals 1 Broderick JP Palesch YY Demchuk AM Yeatts SD Khatri P Hill MD et al. Endovascular therapy after intravenous t-PA versus t-PA only for stroke. N Engl J Med. 2013;368:893-903. [PMC free article] [PubMed] 2 Demchuk AM. IMS III Investigators. IMS III: Assessment of results between Ambrisentan (BSF 208075) IV and.