Computed tomography angiography for quantification of cerebral vasospasm following aneurysmal subarachnoid hemorrhage

PURPOSE

The purpose of this study was to assess the accuracy of computed tomography angiography (CTA) for quantification of cerebral vasospasm following aneurysmal subarachnoid hemorrhage in proximal and middle segments of intracranial arteries.

MATERIALS AND METHODS

Twenty consecutive patients (7 men, 13 women; mean age, 47 ± 7 [SD] years; age range: 27-78 years) with aneurysmal subarachnoid hemorrhage who underwent CTA and digital subtracted angiography (DSA) with a 6-hour window at baseline and during vasospasm period were included. Twelve artery segments were analyzed in each patient. Vasospasm was blindly quantified on CTA and digital subtracted angiography (DSA) by two independent readers with discordance > 10% resolved by open data consensus. Inter-reader and inter-test correlations with DSA as reference, and causes of discordant readings were analyzed. The best sensitivity and specificity of CTA for determination of vasospasm ≥ 50% on DSA was determined using receiver operating curve analysis.

RESULTS

Two-hundred-and-ten arterial segments were analyzed after exclusion of 30 segments with missing data or metallic artifacts. An inter-reader discordance >10% was observed in 82 segments (82/210; 39% [95% CI: 32-46]). Inter-test discordances >10% were observed respectively in 115 segments (115/210; 55% [95% CI: 49-62]) with the junior reader and in 73 segments (73/210; 35% [95% CI: 29-42]) with the senior reader. They were related to reader error in 55 (55/210; 26% [95% CI: 20-32]) with the junior reader and 13 (13/210; 6% [95% CI: 3-9]) with the senior reader, as well systematic biases in 8 (8/210; 4% [95% CI: 1-6]), and intrinsic limitation in 52 (52/210; 25% [95% CI: 19-31]). Best sensitivity and specificity of CTA were observed for a threshold value of 30% (sensitivity = 88% [95% CI: 78-97%]; specificity = 84% [95% CI: 77-90%]; area under curve = 0.92 [95% CI: 0.86-0.97]). On a patient basis, sensitivity was 100% (specificity = 60% [95% CI: 38-81%]; area under curve = 0.97 [95% CI: 89-100%] for this same threshold.

CONCLUSION

Our study shows a moderate accuracy of CTA for the quantification of cerebral vasospasm, mostly related to challenging interpretation and intrinsic limitations. CTA may rule-out angiographic vasospasm ≥ 50% when no segment has vasospasm over than 30%.

Delayed Cerebral Infarction is Systematically Associated with a Cerebral Vasospasm of Large Intracranial Arteries

BACKGROUND

Whether delayed cerebral infarction (DCIn) after aneurysmal subarachnoid hemorrhage (aSAH) is driven by large artery vasospasm is still controversial.

OBJECTIVE

To study the association between DCIn and vasospasm by using quantitative assessment of vasospasm up to distal arteries with time and territorial-based correlation.

METHODS

Clinical and imaging data of 392 patients with aSAH treated at our center between 2012 and 2017 were reviewed. DCIn was defined as any cerebral infarction occurring within 3 to 21 d after ictus and not related to other specific cause. In patients with DCIn, vasospasm was assessed within 24 h around DCIn for each cerebral artery up to the end of the 2nd segments. DCIn and vasospasm analyses were blinded.

RESULTS

DCIn was found in 11% of patients (inter-rater k = 0.90, computed tomography (CT)-scan = 100%, follow-up MRI = 91%). Vasospasm was quantified in 258 artery territories including 66 with and 192 without DCIn (DSA = 93%, computed tomography angiography = 7%). Vasospasm was more severe in DCIn than in non-DCIn territories (60% [55-69] vs 20% [0-50], P < .001). Vasospasm was associated with DCIn in a "dose-dependent" manner (P for trend = .022). Every DCIn territory had a vasospasm ≥ 50%, including 39% only of distal artery segments. Only 9% of non-DCIn territories had vasospasm ≥ vasospasm in DCIn territories.

CONCLUSION

The necessary association between severe vasospasm and DCIn in our study brings additional arguments in favor of large artery vasospasm (especially of distal segments) as a major determinant of DCIn and a potential therapeutic target.

Distal Balloon Angioplasty of Cerebral Vasospasm Decreases the Risk of Delayed Cerebral Infarction

BACKGROUND AND PURPOSE

Conventional angioplasty of cerebral vasospasm combines proximal balloon angioplasty (up to the first segment of cerebral arteries) with chemical angioplasty for distal arteries. Distal balloon angioplasty (up to the second segment of cerebral arteries) has been used in our center instead of chemical angioplasty since January 2015. We aimed to assess the effect of this new approach in patients with aneurysmal SAH.

MATERIALS AND METHODS

The occurrence, date, territory, and cause of any cerebral infarction were retrospectively determined and correlated to angioplasty procedures. Delayed cerebral infarction, new angioplasty in the territory of a previous angioplasty, angioplasty complications, 1-month mortality, and 6- to 12-month modified Rankin Scale ≤ 2 were compared between 2 periods (before-versus-after January 2015, from 2012 to 2017) with adjustment for age, sex, World Federation of Neurosurgical Societies score, and the modified Fisher grade.

RESULTS

Three-hundred-ninety-two patients were analyzed (160 before versus 232 after January 2015). Distal balloon angioplasty was associated with the following: higher rates of angioplasty (43% versus 27%, P < .001) and intravenous milrinone (31% versus 9%, P < .001); lower rates of postangioplasty delayed cerebral infarction (2.2% versus 7.5%, P = .01) and new angioplasty (8% versus 19%, P = .003) independent of the rate of patients treated by angioplasty and milrinone; and the same rates of stroke related to angioplasty (3.6% versus 3.1%, P = .78), delayed cerebral infarction (7.7% versus 12.5%, P = .12), mortality (10% versus 11%, P = .81), and favorable outcome (79% versus 73%, P = .21).

CONCLUSIONS

Our study suggests that distal balloon angioplasty is safe and decreases the risk of delayed cerebral infarction and the recurrence of vasospasm compared with conventional angioplasty. It fails to show a clinical benefit possibly because of confounding changes in adjuvant therapies of vasospasm during the study period.

'Tempos' management in primary care: a key factor for classifying adverse events, and improving quality and safety

BACKGROUND

The role of time management in safe and efficient medicine is important but poorly incorporated into the taxonomies of error in primary care. This paper addresses the lack of time management, presenting a framework integrating five time scales termed 'Tempos' requiring parallel processing by GPs: the disease's tempo (unexpected rapid evolutions, slow reaction to treatment); the office's tempo (day-to-day agenda and interruptions); the patient's tempo (time to express symptoms, compliance, emotion); the system's tempo (time for appointments, exams, and feedback); and the time to access to knowledge. The art of medicine is to control all of these tempos in parallel and simultaneously.

METHOD

Two qualified physicians reviewed a sample of 1046 malpractice claims from one liability insurer to determine whether a medical injury had occurred and, if so, whether it was due to one or more tempo-related problems. 623 of these reports were analysed in greater detail to identify the prevalence and characteristics of claims and related time management errors.

RESULTS

The percentages of contributing factors were as follows: disease tempo, 37.9%; office tempo, 13.2%; patient tempo, 13.8%; out-of-office coordination tempo, 22.6%; and GP's access to knowledge tempo, 33.2%.

CONCLUSION

Although not conceptualised in most error taxonomies, the disease and patient tempos are cornerstones in risk management in primary care. Traditional taxonomies describe events from an analytical perspective of care at the system level and offer opportunities to improve organisation, process, and evidence-based medicine. The suggested classification describes events in terms of (unsafe) dynamic control of parallel constraints from the carer's perspective, namely the GP, and offers improvement on how to self manage and coordinate different contradictory tempos and day-to-day activities. Further work is needed to test the validity and usefulness of this approach.

[Which definition and taxonomy of incident to use for a French reporting system in primary care settings?]

BACKGROUND

There is no widely accepted definition of incident for primary care doctors in France and no taxonomic classification system for epidemiological use. In preparation for a future epidemiological study on primary care incidents in France (the ESPRIT study), this work was designed to identify the definitions and taxonomic classifications used internationally along with the usual methods and results in terms of frequency in the literature. The goal was to determine a French definition and taxonomy.

DESIGN

Systematic review of the literature and consensus methods.

METHOD

An exhaustive search of epidemiological surveys was performed. A structured grid was used. After having identified the definitions used in the literature, a definition was chosen using the focus groups method. Taxonomies identified in the literature were classified by relationship, architecture, code number, and number of studies published. Subsequently, a consensus among experts, who independently tested these taxonomies on six incidents, was reached for choosing the most appropriate for epidemiological data collection (little information on a large number of cases).

RESULTS

Twenty-four papers reporting 17 studies were selected among 139 articles. Five definitions and eight taxonomies were found. The chosen definition of incident was based on the WHO definition "A patient safety incident is an event or circumstance that could have resulted, or did result, in harm to a patient, and whose wish it is not repeated again". The test of incidents resulted in the choice of the TAPS version of the International Taxonomy of Medical Error in Primary Care for a reproducible and internationally recognized codification and the tempos method for its current use in French general practice.

DISCUSSION

The definitions, taxonomies, data collection characteristics and frequency of incidents results in the international literature on incidents in primary care are key components for the preparation of an epidemiological survey on incidents in primary care.

Respiratory muscle performance in patients with type 1 diabetes

Respiratory muscle strength and endurance were examined in 31 Type 1 diabetic patients and in age, sex, and weight matched control subjects. No significant difference in respiratory muscle strength was noted between the two groups. Maximal static inspiratory pressure was 92.3 +/- 33.9 (+/- SD) and 99.5 +/- 23.0% of the predicted values in the patient and control groups, respectively. Maximal static expiratory pressures were 75.1 +/- 14.3 and 77.4 +/- 14.0% of the predicted values in the patient and control groups, respectively. Respiratory muscle endurance was significantly lower in the diabetic patients 88.9 +/- 20.7 vs 103.9 +/- 15.8% predicted in the control group (p less than 0.01). Total lung capacity, vital capacity, and maximal voluntary ventilation were also significantly lower in the diabetic group and correlated with the duration of diabetes.