Reliability of the Diagnosis of Cerebral Vasospasm Using Catheter Cerebral Angiography: A Systematic Review and Inter- and Intraobserver Study

Reliability of study endpoint adjudication in a pragmatic trial on brain arteriovenous malformations

BACKGROUND

The results of a clinical trial are given in terms of primary and secondary outcomes that are obtained for each patient. Just as an instrument should provide the same result when the same object is measured repeatedly, the agreement of the adjudication of a clinical outcome between various raters is fundamental to interpret study results. The reliability of the adjudication of study endpoints determined by examination of the electronic case report forms of a pragmatic trial has not previously been tested.

METHODS

The electronic case report forms of 62/434 (14%) patients selected to be observed in a study on brain AVMs were independently examined twice (4 weeks apart) by 8 raters who judged whether each patient had reached the following study endpoints: (1) new intracranial hemorrhage related to AVM or to treatment; (2) new non-hemorrhagic neurological event; (3) increase in mRS ≥1; (4) serious adverse events (SAE). Inter and intra-rater reliability were assessed using Gwet's AC1 (κG) statistics, and correlations with mRS score using Cramer's V test.

RESULTS

There was almost perfect agreement for intracranial hemorrhage (92% agreement; κG = 0.84 (95%CI: 0.76-0.93), and substantial agreement for SAEs (88% agreement; κG = 0.77 (95%CI: 0.67-0.86) and new non-hemorrhagic neurological event (80% agreement; κG = 0.61 (95%CI: 0.50-0.72). Most endpoints correlated (V = 0.21-0.57) with an increase in mRS of ≥1, an endpoint which was itself moderately reliable (76% agreement; κG = 0.54 (95%CI: 0.43-0.64).

CONCLUSION

Study endpoints of a pragmatic trial were shown to be reliable. More studies on the reliability of pragmatic trial endpoints are needed.

CTA Supplemented by CTP Increases Interrater Reliability and Endovascular Treatment Use in Patients with Aneurysmal SAH

BACKGROUND AND PURPOSE

Cerebral vasospasm is a common complication of aneurysmal SAH and remains a risk factor for delayed cerebral ischemia and poor outcome. The interrater reliability of CTA in combination with CTP has not been sufficiently studied. We aimed to investigate the reliability of CTA alone and in combination with CTP in the detection of cerebral vasospasm and the decision to initiate endovascular treatment.

MATERIALS AND METHODS

This is a retrospective single-center study including patients treated for aneurysmal SAH. Inclusion criteria were a baseline CTA and follow-up imaging including CTP due to suspected vasospasm. Three neuroradiologists were asked to grade 15 intracranial arterial segments in 71 cases using a tripartite scale (no, mild <50%, or severe >50% vasospasm). Raters further evaluated whether endovascular treatment should be indicated. The ratings were performed in 2 stages with a minimum interval of 6 weeks. The first rating included only CTA images, whereas the second rating additionally encompassed CTP images. All raters were blinded to any clinical information of the patients.

RESULTS

Interrater reliability for per-segment analysis of vessels was highly variable (κ = 0.16-0.61). We observed a tendency toward higher interrater reliability in proximal vessel segments, except for the ICA. CTP did not improve the reliability for the per-segment analysis. When focusing on senior raters, the addition of CTP images resulted in higher interrater reliability for severe vasospasm (κ = 0.28; 95% CI, 0.10-0.46 versus κ = 0.46; 95% CI, 0.26-0.66) and subsequently higher concordance (κ = 0.23; 95% CI, -0.01-0.46 versus κ = 0.73; 95% CI, 0.55-0.91) for the decision of whether endovascular treatment was indicated.

CONCLUSIONS

CTA alone offers only low interrater reliability in the graduation of cerebral vasospasm. However, using CTA in combination with CTP might help, especially senior neuroradiologists, to increase the interrater reliability to identify severe vasospasm following aneurysmal SAH and to increase the reliability regarding endovascular treatment decisions.

Twelve controversial questions in aneurysmal subarachnoid hemorrhage

Critical care management of aneurysmal subarachnoid hemorrhage (aSAH) remains a major challenge. Despite the recent publication of guidelines from the American Heart Association/American Stroke Association and the Neurocritical Care Society, there are many controversial questions in the intensive care unit (ICU) management of this population. The authors provide an analysis of common issues in the ICU and provide guidance on the daily management of this specific population of neurocritical care patients.

Should individual timeline and serial CT/MRI panels of all patients be presented in acute brain insult cohorts? A pilot study of 45 patients with decompressive craniectomy after aneurysmal subarachnoid hemorrhage

PURPOSE

Our review of acute brain insult articles indicated that the patients' individual (i) timeline panels with the defined time points since the emergency call and (ii) serial brain CT/MRI slice panels through the neurointensive care until death or final brain tissue outcome at 12 months or later are not presented.

METHODS

We retrospectively constructed such panels for the 45 aneurysmal subarachnoid hemorrhage (aSAH) patients with a secondary decompressive craniectomy (DC) after the acute admission to neurointensive care at Kuopio University Hospital (KUH) from a defined population from 2005 to 2018. The patients were indicated by numbers (1.-45.) in the pseudonymized panels, tables, results, and discussion. The timelines contained up to ten defined time points on a logarithmic time axis until death ([Formula: see text]; 56%) or 3 years ([Formula: see text]; 44%). The brain CT/MRI panels contained a representative slice from the following time points: SAH diagnosis, after aneurysm closure, after DC, at about 12 months (20 survivors).

RESULTS

The timelines indicated re-bleeds and allowed to compare the times elapsed between any two time points, in terms of workflow swiftness. The serial CT/MRI slices illustrated the presence and course of intracerebral hemorrhage (ICH), perihematomal edema, intraventricular hemorrhage (IVH), hydrocephalus, delayed brain injury, and, in the 20 (44%) survivors, the brain tissue outcome.

CONCLUSIONS

The pseudonymized timeline panels and serial brain imaging panels, indicating the patients by numbers, allowed the presentation and comparison of individual clinical courses. An obvious application would be the quality control in acute or elective medicine for timely and equal access to clinical care.

Understanding power in randomized trials: The example of vertebroplasty

OBJECTIVES

Randomized trials (RCTs) should include a sufficient number of patients to reduce the risk that the observed outcome is a result of chance rather than from a truly different treatment effect. Trials must be even larger to claim an absence of treatment effect in a placebo-controlled trial. To estimate the size of the trial and maximize power, it is often suggested to use a comparison between the means of a continuous variable.

METHODS

We examine the RCTs that have compared vertebroplasty and placebo for patients with osteoporotic fractures. Most trials compared the means of a continuous pain score to yield implausibly small trials, as small as 24 patients per group.

RESULTS

The minimally significant difference between groups has no precise clinical meaning for patients when it is based on a comparison of means of pain scores. A comparison of the proportions of patients reaching a per-patient outcome measure of treatment success is much more pertinent if the trial is to inform the care of future patients. The resulting trials will admittedly need to be larger, but they will be much less likely to fall prey to the 'evidence of absence' fallacy. Furthermore, trial size should also take into consideration harder clinical outcome measures, such as death and disability.

CONCLUSION

When the goal of a trial is to inform outcome-based medical care, comparing the proportions of patients reaching a clinically pertinent outcome is more appropriate than comparing the means of a continuous variable.

Emerging Materials, Wearables, and Diagnostic Advancements in Therapeutic Treatment of Brain Diseases

Among the most critical health issues, brain illnesses, such as neurodegenerative conditions and tumors, lower quality of life and have a significant economic impact. Implantable technology and nano-drug carriers have enormous promise for cerebral brain activity sensing and regulated therapeutic application in the treatment and detection of brain illnesses. Flexible materials are chosen for implantable devices because they help reduce biomechanical mismatch between the implanted device and brain tissue. Additionally, implanted biodegradable devices might lessen any autoimmune negative effects. The onerous subsequent operation for removing the implanted device is further lessened with biodegradability. This review expands on current developments in diagnostic technologies such as magnetic resonance imaging, computed tomography, mass spectroscopy, infrared spectroscopy, angiography, and electroencephalogram while providing an overview of prevalent brain diseases. As far as we are aware, there hasn't been a single review article that addresses all the prevalent brain illnesses. The reviewer also looks into the prospects for the future and offers suggestions for the direction of future developments in the treatment of brain diseases.

The incidence of cerebral arterial vasospasm following aneurysmal subarachnoid haemorrhage: a systematic review and meta-analysis

Purpose

To describe a pooled estimated incidence of cerebral arterial vasospasm (aVSP) following aneurysmal subarachnoid haemorrhage (aSAH) and to describe sources of variation in the reported incidence.

Methods

We performed a systematic review and meta-analysis of randomised clinical trials (RCTs) and cohort studies. The primary outcome was the proportion of study participants diagnosed with aVSP. We assessed for heterogeneity based on mode of imaging, indication for imaging, study design and clinical characteristics at a study level.

Results

We identified 120 studies, including 19,171 participants. More than 40 different criteria were used to diagnose aVSP. The pooled estimate of the proportion of patients diagnosed with aVSP was 0.42 (95% CI 0.39 to 0.46, I² = 96.5%). There was no evidence that the incidence aVSP was different, nor that heterogeneity was reduced, when the estimate was assessed by study type, imaging modalities, the proportion of participants with high grade CT scores or poor grade clinical scores. The pooled estimate of the proportion of study participants diagnosed with aVSP was higher in studies with routine imaging (0.47, 95% CI 0.43 to 0.52, I² = 96.5%) compared to those when imaging was performed when indicated (0.30, 95% CI 0.25 to 0.36, I² = 94.0%, p for between-group difference < 0.0005).

Conclusion

The incidence of cerebral arterial vasospasm following aSAH varies widely from 9 to 93% of study participants. Heterogeneity in the reported incidence may be due to variation in the criteria used to diagnose aVSP. A standard set of diagnostic criteria is necessary to resolve the role that aVSP plays in delayed neurological deterioration following aSAH.

PROSPERO registration

CRD42020191895

Supplementary Information

The online version contains supplementary material available at 10.1007/s00234-022-03004-w.

Understanding the reliability of trial outcome measures: The example of angiographic results of surgical or endovascular treatments of aneurysms

BACKGROUND

The reliability of outcome measures is of central importance in clinical research. Studies of reliability remain rare in the neurovascular field.

METHODS

A narrative review of the history (1997-2021) of reporting angiographic results of the surgical or endovascular treatments of aneurysms serves to illustrate the importance of precisely defining outcome measures. We also review how the reliability of an angiographic classification system was studied.

DISCUSSION

Outcome measures are commonly used without precise definitions. When definitions or classification systems exist, they are rarely verified for their reliability. Twenty-five years following its introduction, a classification of angiographic results of aneurysm treatments is still being studied and modified.

CONCLUSION

The reliability of outcome measures should be made a research priority if we are to practice outcome-based medical or surgical care.

Transcranial Doppler Velocities and Angiographic Vasospasm after SAH: A Diagnostic Accuracy Study

BACKGROUND AND PURPOSE

After aneurysmal SAH, transcranial Doppler is commonly used to monitor cerebral vasospasm. The diagnostic accuracy of transcranial Doppler flow velocity values in detecting angiographic vasospasm in patients requiring urgent endovascular intervention has not been established.

MATERIALS AND METHODS

We performed a retrospective analysis of a consecutive series of patients with aneurysmal SAH who underwent transcranial Doppler (index test) within 24 hours of conventional angiography (reference test). The judgment of 33%, 50%, and 66% degree of vessel narrowing on angiography was independently established by multiple neuroendovascular clinicians. Vessel-specific per-segment and per-patient transcranial Doppler velocities were studied using receiver operating characteristic curves, the Youden index, and minimal acceptable sensitivity models. Optimal mean flow-velocity thresholds were explored to calculate sensitivity and specificity using a per-patient judgment of vasospasm of at least 50% angiographic narrowing in any large arterial segment except A1.

RESULTS

In 221 patients, vasospasm was found in 15%, 8%, and 4% of arteries when the degree of reference angiographic luminal narrowing was 33%, 50%, and 66%, respectively. Mean flow velocities were significantly higher in vasospastic segments (P = . 001), but per-segment exploratory analyses yielded unsound mean flow velocity thresholds. The Youden and minimal acceptable sensitivity models proposed mean flow velocity thresholds of approximately 160 cm/s for the anterior circulation and 80 cm/s for the posterior circulation in the per-patient diagnosis of angiographic vasospasm (≥50%), yielding a sensitivity of 80%-90% (95% CI, 0.77-0.96), but with a corresponding specificity of 50% (95% CI, 0.40-0.56).

CONCLUSIONS

In this study, a threshold transcranial Doppler mean flow-velocity value that would accurately diagnose ≥50% angiographic vasospasm remained elusive.

Diagnostic Performance of Computed Tomography Angiography and Computed Tomography Perfusion Tissue Time-to-Maximum in Vasospasm Following Aneurysmal Subarachnoid Hemorrhage

Background

Vasospasm is a treatable cause of deterioration following aneurysmal subarachnoid hemorrhage. Cerebral computed tomography perfusion mean transit times have been proposed as a predictor of vasospasm but suffer from well‐known technical limitations. We evaluated fully automated, thresholded time‐to‐maxima of the tissue residue function (T_max) for determination of vasospasm following aneurysmal subarachnoid hemorrhage.

Methods and Results

Retrospective analysis of 540 arterial segments from 36 encounters in 31 consecutive patients with aneurysmal subarachnoid hemorrhage undergoing computed tomography angiography (CTA), computed tomography perfusion, and digital subtraction angiography (DSA) within 24 hours. T_max at 4, 6, 8, and 10 s was generated using RAPID (iSchemaView Inc., Menlo Park, CA). Dual‐reader CTA and computed tomography perfusion interpretations were compared for patients with and without vasospasm on DSA (DSA+ and DSA−). Logistic regression models were developed using CTA and T_max as input predictors and DSA vasospasm as outcome in adjusted and unadjusted models. Imaging studies from all 31 subjects (mean age 47.3±11.1, 77% female, 65% with single aneurysm with mean size of 6.0±2.9 mm) were included. Vasospasm was identified in 42 segments on DSA and 59 segments on CTA, with significant associations across individual vessel segments (P<0.001). In adjusted analyses, DSA vasospasm was associated with CTA (odds ratio [OR], 2.43; 95% CI, 0.94–6.32; P=0.068) as well as territory‐specific T_max>6 seconds delays (OR, 3.57; 95% CI, 1.36–9.35; P=0.009). Sensitivity/specificity for DSA vasospasm was 31%/91% for CTA, 26%/89% for T_max>6 seconds, and 12%/99% for CTA+T_max>6 seconds.

Conclusions

CTA and T_max offer high specificity for presence of vasospasm; their utility, even in combination, as screening tests is, however, limited by poor sensitivity.

Diffuse Angiogram-Negative Subarachnoid Hemorrhage is Associated with an Intermediate Clinical Course

BACKGROUND

The cerebral angiography result is negative for an underlying vascular lesion in 15-20% of patients with nontraumatic subarachnoid hemorrhage (SAH). Patients with angiogram-negative SAH include those with perimesencephalic SAH and diffuse SAH. Consensus suggests that perimesencephalic SAH confers a more favorable prognosis than diffuse SAH. Limited data exist to contextualize the clinical course and prognosis of diffuse SAH in relation to aneurysmal SAH in terms of critical care complications, neurologic complications, and functional outcomes. Here we compare the clinical course and functional outcomes of patients with perimesencephalic SAH, diffuse SAH, and aneurysmal SAH to better characterize the prognostic implications of each SAH subtype.

METHODS

We conducted a retrospective cohort study that included all patients with nontraumatic SAH admitted to a tertiary care referral center between January 1, 2012, and December 31, 2017. Bleed patterns were radiographically adjudicated, and patients were assigned to three groups: perimesencephalic SAH, diffuse SAH, and aneurysmal SAH. Patient demographics, complications, and clinical outcomes were reported and compared.

RESULTS

Eighty-six patients with perimesencephalic SAH, 174 with diffuse SAH, and 998 with aneurysmal SAH presented during the study period. Patients with aneurysmal SAH were significantly more likely to be female, White, and active smokers. There were no significant differences between patients with diffuse SAH and perimesencephalic SAH patterns. Critical care complications were compared across all three groups, with significant between-group differences in hypotension and shock (3.5% vs. 16.1% vs. 38.4% for perimesencephalic SAH vs. diffuse SAH vs. aneurysmal SAH, respectively; p < 0.01) and endotracheal intubation (0% vs. 26.4% vs. 48.8% for perimesencephalic SAH vs. diffuse SAH vs. aneurysmal SAH, respectively; p < 0.01). Similar trends were noted with long-term supportive care with tracheostomy and gastrostomy tubes and length of stay. Cerebrospinal fluid diversion was increasingly required across bleed types (9.3% vs. 54.6% vs. 76.3% for perimesencephalic SAH vs. diffuse SAH vs. aneurysmal SAH, respectively, p < 0.001). Vasospasm and delayed cerebral ischemia were comparable between perimesencephalic SAH and diffuse SAH but significantly lower than aneurysmal SAH. Patients with diffuse SAH had intermediate functional outcomes, with significant rates of nonhome discharge (23.0%) and poor functional status on discharge (26.4%), significantly higher than patients with perimesencephalic SAH and lower than patients with aneurysmal SAH. Diffuse SAH similarly conferred an intermediate rate of good functional outcomes at 1-6 months post discharge (92.3% vs. 78.6% vs. 47.3% for perimesencephalic SAH vs. diffuse SAH vs. aneurysmal SAH, respectively; p < 0.016).

CONCLUSIONS

We confirm the consensus data that perimesencephalic SAH is associated with a more benign clinical course but demonstrate that diffuse SAH confers an intermediate prognosis, more malignant than perimesencephalic SAH but not as morbid as aneurysmal SAH. These results highlight the significant morbidity associated with diffuse SAH and emphasize need for vigilance in the acute care of these patients. These patients will likely benefit from continued high-acuity observation and potential support to avert significant risk of morbidity and neurologic compromise.

Angiographic vasospasm and delayed cerebral ischemia after subarachnoid hemorrhage: Moving from theoretical to practical research pertinent to neurosurgical care

BACKGROUND AND PURPOSE

Delayed cerebral ischemia (DCI) and angiographic vasospasm following subarachnoid hemorrhage (SAH) have been associated for more than 50years. We aimed to examine whether the knowledge gained by theoretical research on vasospasm has actually translated into better patient outcomes in practice.

METHODS

This is a narrative review of the concept of vasospasm as a cause of DCI after SAH. We discuss recent studies that have assessed the accuracy and reliability of the diagnostic tests (transcranial Doppler ultrasound [TCD], CT angiography, and catheter angiography), which are used to identify SAH patients at-risk of DCI.

RESULTS

Both the diagnostic accuracy of TCD and the reliability of CT angiography to identify patients in severe vasospasm are poor. For the gold standard catheter angiography, the repeatability of the diagnosis of vasospasm, made by multiple raters, is only fair. Interventions on angiographic vasospasm have never been proven to improve patient outcomes. A pragmatic trial integrating the meaning of the diagnosis of vasospasm into a study protocol that assesses the value of endovascular interventions in the prevention of DCI after SAH seems to be in order. Such a trial could provide a pragmatic definition of clinically meaningful vasospasm.

CONCLUSION

We must move beyond research conceived as an enterprise aiming to acquire theoretical knowledge to one where research is integrated into clinical practice to improve clinical outcomes in real time.