Computed tomography perfusion–based selection of patients for endovascular recanalization

Clinical Outcome Predicted by Collaterals Depends on Technical Success of Mechanical Thrombectomy in Middle Cerebral Artery Occlusion

BACKGROUND

This study aimed to analyze the effects of technical outcome of mechanical thrombectomy (MTE) on the associations between collateral status, assessed with pretreatment computed tomography angiography (CTA), and neurological and functional outcome, as well as associations between collaterals and metabolic risk factors (arterial hypertension, diabetes, hyperlipidemia, overweight).

METHODS

Prospectively collected data of 115 patients with CTA-proven isolated middle cerebral artery occlusion treated successfully with MTE (Thrombosis in Cerebral Infarction [TICI] scale 2b or 3) were assessed retrospectively. Initial CTAs were assessed for the regional leptomeningeal collateralization score (rLMC), neurological status was determined with the National Institutes of Health Stroke Scale (NIHSS) at admission and discharge, and mid-term functional outcome was assessed using the modified Rankin scale (mRS) 90 days after MTE.

RESULTS

NIHSS score at admission was significantly associated with rLMC (P = .004), whereas rLMC and NIHSS at discharge showed no significant associations (P = .12). Better rLMC was significantly associated with improved mid-term mRS (P = .018). This association was even more significant after complete MTE (TICI 3; P = .011). Arterial hypertension was significantly more often found in patients with poor rLMC (0-10) than in patients with good rLMC (11-20; P = .046), yet other risk factors showed no significant associations (P > .05).

CONCLUSIONS

In patients with successful MTE, good collaterals were associated with better neurological status at admission and favorable mid-term functional outcome. In patients with complete MTE, associations were even more significant compared with those with "almost complete" MTE, suggesting a synergistic effect between good collaterals and complete MTE and a predictive value of collaterals for estimation of the potential clinical benefit of MTE.

Endovascular stroke intervention in young patients with large vessel occlusions

OBJECT

Endovascular therapy has become a widely used method for achieving arterial recanalization in patients who are ineligible for intravenous thrombolysis or those in whom it is unsuccessful. Young stroke patients with large vessel occlusions may particularly benefit from endovascular intervention. This study aims to assess the authors' experience with the use of modern endovascular techniques to treat young patients (≤ 55 years old) with acute ischemic stroke and large vessel occlusions.

METHODS

Young patients (≤ 55 years old) undergoing endovascular intervention for acute ischemic stroke at the authors' institution were identified from a prospectively maintained database. Only those patients with a confirmed large vessel occlusion were included. Modified Rankin Scale (mRS) scores were determined at 90 days during a follow-up visit. A multivariate analysis was performed to determine predictors of outcome (mRS score 0-2).

RESULTS

A total of 45 patients met the inclusion criteria. The mean age of the patients in this series was 45 ± 9.6 years. The mean admission NIH Stroke Scale score was 14.1 ± 5 (median 13.5). Mechanical thrombectomy was performed using the Solitaire FR device in 13 (29%) patients and the Merci/Penumbra systems in 32 (71%) patients. The rate of successful recanalization (Thrombolysis In Myocardial Infarction [TIMI] scale Grade II-III) was 93% (42/45). Only 1 patient (2.2%) had a symptomatic intracranial hemorrhage following intervention. One patient (2.2%) sustained a vessel perforation intraoperatively. The rate of 90-day favorable outcome (mRS score 0-2) was 77.5% and the rate of 90-day satisfactory outcome (mRS score 0-3) was 90%. The 90-day mortality rate was 7.5%. In multivariate analysis, postprocedure TIMI grade was the only statistically significant independent predictor of 90-day outcome (OR 3.3, 95% CI 1.01-1.19; p = 0.05).

CONCLUSIONS

The results of this study demonstrate that endovascular therapy provides remarkably high rates of arterial recanalization and favorable outcomes in young patients with acute ischemic stroke and large vessel occlusions. These findings support aggressive interventional strategies in these patients. Randomized, controlled trials reflecting modern acute ischemic stroke treatment will be needed to confirm the findings of this study.

Saving the ischemic penumbra: endovascular thrombolysis versus medical treatment

Endovascular thrombolysis may allow rapid arterial recanalization in patients with acute ischemic stroke. We present the first study to our knowledge comparing the ischemic penumbra saved with endovascular versus medical therapy. A retrospective review of 21 patients undergoing endovascular intervention for stroke from 2010 to 2011 was contrasted with 21 consecutive patients treated with antiplatelet agents alone. Immediate computed tomography perfusion (CTP) scan of the head and neck was obtained in all patients. Patients with lacunar and posterior circulation infarcts, and those who were medically unstable for MRI post-operatively were excluded. CTP and MRI underwent volumetric calculation. CTP penumbra was correlated with diffusion restriction volumes on MRI, and an assessment was made on the volume of ischemic burden saved with either endovascular treatment or antiplatelet agents. The median age was 70 years (interquartile range 62-80). Median National Institutes of Health Stroke Scale score was 18 and 14 in the control and endovascular groups, respectively. Intravenous tissue plasminogen activator was administered in 22 of 42 patients (52%). Median penumbra calculated was 32,808 mm(3) in the control group and 46,255 mm(3) in the endovascular group. Median penumbra spared was 9550 mm(3) (4980-18,811) in the control group versus 38,155 mm(3) in the endovascular group (p=0.0001). Endovascular thrombolysis may be more efficient than medical therapy alone in saving ischemic penumbra. Future advances in recanalization techniques will further improve the efficacy of endovascular therapy.

Diagnostic and Prognostic Impact of pc-ASPECTS Applied to Perfusion CT in the Basilar Artery International Cooperation Study

BACKGROUND AND PURPOSE

The posterior circulation Acute Stroke Prognosis Early CT Score (pc-APECTS) applied to CT angiography source images (CTA-SI) predicts the functional outcome of patients in the Basilar Artery International Cooperation Study (BASICS). We assessed the diagnostic and prognostic impact of pc-ASPECTS applied to perfusion CT (CTP) in the BASICS registry population.

METHODS

We applied pc-ASPECTS to CTA-SI and cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) parameter maps of BASICS patients with CTA and CTP studies performed. Hypoattenuation on CTA-SI, relative reduction in CBV or CBF, or relative increase in MTT were rated as abnormal.

RESULTS

CTA and CTP were available in 27/592 BASICS patients (4.6%). The proportion of patients with any perfusion abnormality was highest for MTT (93%; 95% confidence interval [CI], 76%-99%), compared with 78% (58%-91%) for CTA-SI and CBF, and 46% (27%-67%) for CBV (P < .001). All 3 patients with a CBV pc-ASPECTS < 8 compared to 6/23 patients with a CBV pc-ASPECTS ≥ 8 had died at 1 month (RR 3.8; 95% CI, 1.9-7.6).

CONCLUSION

CTP was performed in a minority of the BASICS registry population. Perfusion disturbances in the posterior circulation were most pronounced on MTT parameter maps. CBV pc-ASPECTS < 8 may indicate patients with high case fatality.

Pretreatment advanced imaging in patients with stroke treated with IV thrombolysis: evaluation of a multihospital data base

BACKGROUND AND PURPOSE

CT angiography, CT perfusion, and MR imaging have all been advocated as potentially useful in treatment planning for patients with acute ischemic stroke. We evaluated a large multihospital data base to determine how the use of advanced imaging is evolving in patients treated with intravenous thrombolysis.

MATERIALS AND METHODS

Patients with acute ischemic stroke receiving IV thrombolytic therapy from 2008 to 2011 were identified by using the Premier Perspective data base. Mortality and discharge to long-term care rates were compared following multivariate logistic regression between patients who received head CT only versus those who received CTA without CT perfusion, CT perfusion, or MR imaging.

RESULTS

Of 12,429 included patients, 7305 (59%) were in the CT group, 2359 (19%) were in the CTA group, 848 (7%) were in the CTP group, and 1917 (15%) were in the MR group. From 2008 to 2011, the percentage of patients receiving head CT only decreased from 64% to 55%, while the percentage who received cerebral CT perfusion increased from 3% to 8%. The use of CT angiography and MR imaging marginally increased (1%-2%). Outcomes were similar between CT only and advanced imaging patients, except discharge to long-term care was slightly more frequent in the CTP group (OR = 1.17 [95% CI, 0.96-1.43]; P = .0412) and MR group (OR = 1.14 [95% CI, 1.01-1.28]; P = .0177) and mortality was lower in the MR group (OR = 0.64 [95% CI, 0.52-0.79]; P < .0001).

CONCLUSIONS

Use of advanced imaging is increasing in patients treated with IV thrombolysis. While there were differences in outcomes among imaging groups, the clinical effect of advanced imaging remains unclear.

CT perfusion-guided versus time-guided mechanical recanalization in acute ischemic stroke patients

OBJECTIVE

Perfusion studies are increasingly used to triage acute stroke patients for endovascular recanalization therapies. We compare the safety and efficacy of CT perfusion (CTP)-guided to time-guided mechanical recanalization in acute ischemic stroke (AIS) patients.

METHODS

A review was conducted on 132 patients, 94 undergoing CTP-guided and 38 undergoing time-guided (maximum 8h from symptom onset) mechanical recanalization at our institution.

RESULTS

The rate of partial-to-complete recanalization did not differ between the CTP and the non-CTP group (78.7% vs. 81.6%, respectively, p=0.71). ICH occurred respectively in 18.1% in the CTP group versus 31.6% in the non-CTP group (p=0.06). The overall in-hospital mortality rate was significantly lower in the CTP group (15.9% vs. 36.8%, p=0.04). In multivariable analysis, CTP-guided patient selection was an independent negative predictor of in-hospital mortality (OR=3.2; p=0.01). CTP-guided patient selection, however, was not a predictor of favorable outcome (Modified Rankin Scale 0-2 or 0-3).

CONCLUSIONS

CTP-based patient selection was associated with lower ICH and mortality rates. Favorable outcomes, however, did not differ between the 2 groups. These results may suggest a possible benefit in terms of in-hospital mortality with CTP-guided triage of AIS patients for endovascular treatment.

A 5-item prediction rule to identify severe renal dysfunction in patients with acute stroke

BACKGROUND AND PURPOSE

Although patients with severe renal dysfunction who receive iodinated contrast are at high risk of CIN, contrast-enhanced CT scans are often obtained without prior knowledge of kidney function in patients with acute stroke. We aimed to develop a tool to identify patients with acute stroke at a high risk of CIN in the absence of a recent GFR.

MATERIALS AND METHODS

We used the RCSN (9872 patients) and OSA (2544 patients) for our derivation and validation cohort, respectively. A multivariable logistic regression model was performed to develop a predictive tool to identify severe renal dysfunction (defined as a GFR < 30 mL/min/1.73 m(2)).

RESULTS

The overall prevalence of severe renal dysfunction was 4.9% and 5.2% in the derivation and validation cohort, respectively. The prediction rule was designed as follows: (age in years) + (5 points for women) + (5 points for history of diabetes mellitus) + (15 points for preadmission insulin use) + (10 points for history of hypertension). The prevalence of severe renal dysfunction is negligible in patients with a total score of ≤70 (≤0.005%-0.7%) but increases with higher Renal Risk Scores (eg, scores 71-80: 2.1%-2.2%; scores 91-100: 6.6%-7.1%; scores 111-120: 15.9%-28.1%).

CONCLUSIONS

The Renal Risk Score is a validated tool that helps clinicians select which patients with stroke can safely proceed to contrast-enhanced brain imaging without waiting for laboratory evidence of good renal function.

Beyond the time window of intravenous thrombolysis: standing by or by stenting?

Intravenous administration of tissue plasminogen activator within 4.5 h of symptom onset is presently the 'golden rule' for treating acute ischemic stroke. However, many patients miss the time window and others reject this treatment due to a long list of contraindications. Mechanical embolectomy has recently progressed as a potential alternative for treating patients beyond the time window for IV thrombolysis. In this paper, recent progress in mechanical embolectomy, angioplasty, and stenting in acute stroke is reviewed. Despite worries concerning the long-term clinical outcomes and increased risk of intracranial hemorrhage, favorable clinical outcomes may be achieved after mechanical embolectomy in carefully selected patients even 4.5 h after stroke onset. Potential steps should be prepared and attempted in these patients whose opportunity for recovery will elapse in a flash.

Interventional stroke therapies in the elderly: are we helping?

BACKGROUND AND PURPOSE

It is unclear whether endovascular therapies for the treatment of AIS are being offered or are safe in older adults. The use and safety of endovascular interventions in patients older than 75 years of age were assessed.

MATERIALS AND METHODS

A retrospective review of patients with AIS 75 years or older (n = 37/1064) was compared with a younger cohort (n = 70/1190) by using an established data base. Admission and discharge NIHSS scores, rates of endovascular treatment, SICH, in-hospital mortality, and the mBI were assessed.

RESULTS

Rates of endovascular treatments were significantly lower in older patients (5.9% in the younger-than-75-year versus 3.5% in the older-than-75-year cohort, P = .007). Stroke severity as measured by the NIHSS score was equivalent in the 2 age groups. The mBI at 12 months was worse in the older patients (mild or no disability in 52% of the younger-than-75-year and 22% in the 75-year-or-older cohort, P = .006). Older patients had higher rates of SICH (9% in younger-than-75-year versus 24% in the 75-year-or-older group, P = .04) and in-hospital mortality (26% in younger-than-75-year versus 46% in the 75-year-or-older group, P = .05).

CONCLUSIONS

Patients older than 75 years of age were less likely to receive endovascular treatments. Older patients had higher rates of SICH, disability, and mortality. Prospective randomized trials are needed to determine the criteria for selecting patients most likely to benefit from acute endovascular therapies.