Usefulness of CT angiography for therapeutic decision making in thrombolyzing intubated patients with suspected basilar artery thrombosis

Fast Protocol for Treating Acute Ischemic Stroke by Emergency Physicians

STUDY OBJECTIVE

Thrombolysis with tissue plasminogen activator should occur promptly after ischemic stroke onset. Various strategies have attempted to improve door-to-needle time. Our objective is to evaluate a strategy that uses an emergency physician-based protocol when no stroke neurologist is available.

METHODS

This was a retrospective before-after intervention analysis in an urban hospital. Reorganization of the acute ischemic stroke treatment process was carried out in 2013. We evaluated time delay, symptomatic intracerebral hemorrhage, and clinical recovery of patients before and after the reorganization. We used multivariable linear regression to estimate the change in door-to-needle time before and after the reorganization.

RESULTS

A total of 107 patients with comparable data were treated with tissue plasminogen activator in 2009 to 2012 (group 1) and 46 patients were treated during 12 months in 2013 to 2014 (group 2). Median door-to-needle time was 54 minutes before the reorganization and 20 minutes after it (statistical estimate of difference 32 minutes; 95% confidence interval 26 to 38 minutes). After adjusting for several potential cofounders in multivariable regression analysis, the only factor contributing to a significant reduction in delay was group (after reorganization versus before). Median onset-to-treatment times were 135 and 119 minutes, respectively (statistical estimate of difference 23 minutes; 95% confidence interval 6 to 39 minutes). The rates of symptomatic intracerebral hemorrhage were 4.7% (5/107) and 2.2% (1/46), respectively (difference 2.5%; 95% confidence interval -8.7% to 9.2%). Approximately 70% of treated patients were functionally independent (modified Rankin Scale score 0 to 2) when treated after the reorganization.

CONCLUSION

Implementation of a stroke protocol with emergency physician-directed acute care decreased both door-to-needle time and onset-to-treatment time without increasing the rate of symptomatic intracerebral hemorrhage.

Acute basilar thrombosis: Recanalization following intravenous thrombolysis is dependent on thrombus length

Introduction

We investigated whether thrombus length measured in Computed Tomography Angiography (CTA) is predictive of the success rate of intravenous thrombolysis (IVT) in acute basilar occlusion and whether recanalization can be achieved by additional mechanical endovascular thrombectomy.

Methods

In 51 patients with acute basilar thrombosis thrombus length was measured on CTA images before intravenous thrombolysis (IVT) with rt-PA was started. After 114 minutes on average success of IVT was evaluated either by CTA or DSA. Patients with persistent basilar occlusion and no major brainstem infarction on CT underwent endovascular recanalization.

Results

87% of patients had no recanalization of basilar artery after IVT alone. The average thrombus length was 15 mm in patients with persistent basilar occlusion after IVT and 7 mm in patients with recanalization after IVT. Thrombi longer than 13 mm did not resolve after IVT alone and 80% of thrombi shorter than 13 mm did not resolve either. 41 patients were transferred to endovascular recanalization; endovascular therapy was performed successfully in 90% (37 / 41).

Conclusions

Recanalization rates in acute basilar occlusion after IVT alone are low and dependent on thrombus length. Additional mechanical endovascular thrombectomy showed to be a very successful recanalization therapy.

CT-angiography source images indicate less fatal outcome despite coma of patients in the Basilar Artery International Cooperation Study

Background

Coma is associated with poor outcome in patients with basilar artery occlusion.

Aims

We sought to assess whether the posterior circulation Acute Stroke Prognosis Early CT Score and the Pons-Midbrain Index applied to CT angiography source images predict the outcome of comatose patients in the Basilar Artery International Cooperation Study.

Methods

Basilar Artery International Cooperation Study was a prospective, observational registry of patients with acute basilar artery occlusion with 48 recruiting centers worldwide. We applied posterior circulation Acute Stroke Prognosis Early CT Score and Pons-Midbrain Index to CT angiography source images of Basilar Artery International Cooperation Study patients who presented with coma. We calculated adjusted risk ratios to assess the association of dichotomized posterior circulation Acute Stroke Prognosis Early CT Score (≥8 vs. <8) and Pons-Midbrain Index (<3 vs. ≥3) with mortality and favourable outcome (modified Rankin Scale score 0–3) at one month.

Results

Of 619 patients in the Basilar Artery International Cooperation Study registry, CT angiography source images were available for review in 158 patients. Among these, 78 patients (49%) presented with coma. Compared to non-comatose patients, comatose patients were more likely to die (risk ratios 2.34; CI 95% 1.56–3.52) and less likely to have a favourable outcome (risk ratios 0.44; CI 95% 0.24–0.80). Among comatose patients, a Pons-Midbrain Index < 3 was related to reduced mortality (adjusted RR 0.66; 95% CI 0.46–0.96), but not to favourable outcome (adjusted RR 1.19; 95% CI 0.39–3.62). Posterior circulation Acute Stroke Prognosis Early CT Score dichotomized at ≥ 8 vs. <8 was not significantly associated with death (adjusted RR 0.70; 95% CI 0.46–1.05).

Conclusion

In comatose patients with basilar artery occlusion, the extent of brainstem ischemia appears to be related to mortality but not to favourable outcome.

Different Imaging Strategies in Patients With Possible Basilar Artery Occlusion: Cost-Effectiveness Analysis

BACKGROUND AND PURPOSE

This study evaluated the cost-effectiveness of different noninvasive imaging strategies in patients with possible basilar artery occlusion.

METHODS

A Markov decision analytic model was used to evaluate long-term outcomes resulting from strategies using computed tomographic angiography (CTA), magnetic resonance imaging, nonenhanced CT, or duplex ultrasound with intravenous (IV) thrombolysis being administered after positive findings. The analysis was performed from the societal perspective based on US recommendations. Input parameters were derived from the literature. Costs were obtained from United States costing sources and published literature. Outcomes were lifetime costs, quality-adjusted life-years (QALYs), incremental cost-effectiveness ratios, and net monetary benefits, with a willingness-to-pay threshold of $80,000 per QALY. The strategy with the highest net monetary benefit was considered the most cost-effective. Extensive deterministic and probabilistic sensitivity analyses were performed to explore the effect of varying parameter values.

RESULTS

In the reference case analysis, CTA dominated all other imaging strategies. CTA yielded 0.02 QALYs more than magnetic resonance imaging and 0.04 QALYs more than duplex ultrasound followed by CTA. At a willingness-to-pay threshold of $80,000 per QALY, CTA yielded the highest net monetary benefits. The probability that CTA is cost-effective was 96% at a willingness-to-pay threshold of $80,000/QALY. Sensitivity analyses showed that duplex ultrasound was cost-effective only for a prior probability of ≤0.02 and that these results were only minimally influenced by duplex ultrasound sensitivity and specificity. Nonenhanced CT and magnetic resonance imaging never became the most cost-effective strategy.

CONCLUSIONS

Our results suggest that CTA in patients with possible basilar artery occlusion is cost-effective.

Basilar artery thrombus vs. fenestration: a differential diagnostic challenge in acute ischemic stroke

We present a case of a man presenting with vertigo and nausea who was found to have multifocal infarcts in the posterior circulation on magnetic resonance imaging (MRI). An magnetic resonance angiography (MRA) demonstrated focal widening and central signal dropout in the distal vertebral artery consistent with arterial fenestration. Transcranial Doppler ultrasonography showed turbulent flow and a spike waveform suggestive of an intra-luminal thrombus. This was confirmed by computed tomography (CT) angiography. Following the initiation of dual antiplatelet therapy, the signal abnormalities on transcranial doppler (TCD) resolved suggesting dissolution of the thrombus. This case highlights the diagnostic pitfalls that may arise when relying on only one modality for assessing intracranial vasculature and the importance of clarifying the diagnosis of basilar thrombosis or fenestration.

Systematic combined noncontrast CT-CT angiography in the management of unexplained nontraumatic coma

BACKGROUND

Nontraumatic impaired consciousness is a common issue in emergency departments with a serious but widely variable prognosis.

STUDY OBJECTIVES

The aim of this prospective study was to evaluate the ability of systematic combined noncontrast computed tomography (NCCT)/computed tomography angiography (CTA) imaging, firstly to provide a neurologic prognosis and secondly to ensure early detection of basilar artery occlusion (BAO), in unexplained nontraumatic impaired consciousness management.

METHODS

Combined NCCT/CTA imaging was performed on 65 patients with impaired consciousness and no history of trauma prospectively over 14 months in a single center. Images were assessed based on visual and quantitative criteria. Clinical outcome was assessed using the modified Rankin Scale at 3 months. Statistical analysis aimed to identify the prognostic value of combined NCCT/CTA imaging and its ability for early BAO detection.

RESULTS

This study shows that combined NCCT/CTA imaging was a significant predictor of poor neurological outcome, with a positive predictive value of 94.6%. The combination was also crucial for early detection of BAO, given that 42.8% of cases were misdiagnosed with NCCT alone. Basilar artery occlusion represented 10.8% of all unexplained nontraumatic impaired consciousness.

CONCLUSIONS

Systematic combined NCCT/CTA imaging is an efficient tool for predicting poor neurologic prognosis in cases of unexplained nontraumatic impaired consciousness and is also essential for detecting BAO.