Cost-Effectiveness of Angiographic Imaging in Isolated Perimesencephalic Subarachnoid Hemorrhage

Comment on Roman-Filip et al. Non-Aneurysmal Perimesencephalic Subarachnoid Hemorrhage: A Literature Review. Diagnostics 2023, 13, 1195

We would like to congratulate Roman-Filip et al. on their recent review on perimesencephalic hemorrhages [...].

Cost-effectiveness of repeat delayed imaging for spontaneous subarachnoid hemorrhage

BACKGROUND

In patients with intracranial aneurysm presenting with spontaneous subarachnoid hemorrhage (SAH), 15% of them could be missed by the initial diagnostic imaging. Repeat delayed imaging can help to identify previously undetected aneurysms, however, the cost-effectiveness of this strategy remains uncertain.

OBJECTIVE

The aim of this study is to assess the cost-effectiveness of repeat delayed imaging in patients with SAH who had a negative result during their initial imaging.

METHODS

A Markov model was developed to estimate the lifetime costs and quality-adjusted life-year (QALY) for patients who received or not received repeat delayed imaging. The analyses were conducted from a healthcare perspective, with costs reported in UK pounds and expressed in 2020 values. Extensive sensitivity analyses were performed to assess the robustness of the results.

RESULTS

The base case incremental cost-effectiveness ratio (ICER) of repeat delayed imaging is £9,314 per QALY compared to no-repeat delayed imaging. This ICER is below the National Institute for Health and Care Excellence (NICE) £20,000 per QALY willingness-to-pay threshold. At the NICE willingness-to-pay threshold of £20,000 per QALY, the probability that repeat delayed imaging is most cost-effective is 0.81. The results are sensitive to age, the utility of survived patients with a favorable outcome, the sensitivity of repeat delayed imaging, and the prevalence of aneurysm.

CONCLUSIONS

This study showed that, in the UK, it is cost-effective to provide repeat delayed imaging using computed tomographic angiography (CTA) for patients with SAH who had a negative result in their initial imaging.

Current status of perimesencephalic non-aneurysmal subarachnoid hemorrhage

Perimesencephalic nonaneurysmal subarachnoid hemorrhage (PNSAH) is a distinctive disease, representing SAH centered in perimesencephalic cisterns, with negative angiography findings. In recent years, the number of patients with PNSAH has increased significantly; however, the knowledge of PNSAH is insufficient. Therefore, we performed a review of the literature from a PubMed search and recounted our understanding of PNSAH. In this review, we summarized that current high-resolution computed tomography angiography is an acceptable replacement for digital subtraction angiography to rule out aneurysms in PNSAH with strict criteria. The current hypothesis about the etiology of PNSAH is that there is deep vein rupture from aberrant venous anatomy and increased intracranial venous pressure. PNSAH is associated with mild symptoms and lower rates of hydrocephalus and symptomatic vasospasm. For PNSAH, conservative treatment has been the mainstream treatment. PNSAH has a benign clinical course and an excellent prognosis; in long-term follow-up, re-bleeding and death were uncommon.

Cost-Effective Analysis of Different Diagnostic Strategies in Screening for Aneurysms After Spontaneous Subarachnoid Hemorrhage

PURPOSE

With an increasing number of patients being treated by coiling for aneurysms, using computed tomographic angiography (CTA) or magnetic resonance angiography (MRA) as an initial screening test becomes less important because digital subtraction angiography (DSA) is the first step of endovascular treatment procedure. The objective of this study is to investigate whether CTA or MRA remained to be the optimal screening strategy in patients with spontaneous subarachnoid hemorrhage (SAH).

METHODS

CTA, MRA, and DSA strategy were evaluated in a decision tree model created with TreeAge Pro Suite 2011. Input parameters were derived from published literature and our institutional database. Base case and sensitivity analyses were conducted to assess the cost-effectiveness of each strategy. A Monte Carlo simulation was performed with all parameters ranged among their distributions to evaluate the validation of results.

RESULTS

The base case scenario showed that MRA was the most cost-effective strategy. Using a willingness-to-pay threshold of ¥70,892/quality adjusted life year, MRA remained to be most cost-effective when its sensitivity is >0.907. DSA was not cost-effective compared to CTA or MRA unless over 91.56% of patients were treated by coiling. The Monte Carlo simulation reported DSA not to be a cost-effective strategy at willingness-to-pay of ¥70,892 in 99.99% of the iterations.

CONCLUSION

DSA is not cost-effective compared to CTA or MRA and should not be used as the initial diagnostic tool for spontaneous SAH.

Subarachnoid Hemorrhage of Unknown Cause: Distribution and Role of Imaging

Subarachnoid hemorrhage of unknown cause represents approximately 10% to 15% of nontraumatic subarachnoid hemorrhages. The key factors in determining the management strategy for a presumed nonaneurysmal subarachnoid hemorrhage are the distribution, location, and amount of subarachnoid blood. Hemorrhage distribution on computed tomography can be categorized as follows: perimesencephalic, diffuse, sulcal, and primary intraventricular. The extent of the workup required in determining the cause of hemorrhage depends on the distribution of blood. The authors review the potential causes, differential diagnoses, and acute and long-term follow-up strategies in patients with subarachnoid hemorrhage of unknown cause.

Neurovascular disease, diagnosis, and therapy: Subarachnoid hemorrhage and cerebral vasospasm

The worldwide incidence of spontaneous subarachnoid hemorrhage is about 6.1 per 100,000 cases per year (Etminan et al., 2019). Eighty-five percent of cases are due to intracranial aneurysms. The mean age of those affected is 55 years, and two-thirds of the patients are female. The prognosis is related mainly to the neurologic condition after the subarachnoid hemorrhage and the age of the patient. Overall, 15% of patients die before reaching the hospital, another 20% die within 30 days, and overall 75% are dead or remain disabled. Case fatality has declined by 17% over the last 3 decades. Despite the improvement in outcome probably due to improved diagnosis, early aneurysm repair, administration of nimodipine, and advanced intensive care support, the outcome is not very good. Even among survivors, 75% have permanent cognitive deficits, mood disorders, fatigue, inability to return to work, and executive dysfunction and are often unable to return to their premorbid level of functioning. The key diagnostic test is computed tomography, and the treatments that are most strongly supported by scientific evidence are to undertake aneurysm repair in a timely fashion by endovascular coiling rather than neurosurgical clipping when feasible and to administer enteral nimodipine. The most common complications are aneurysm rebleeding, hydrocephalus, delayed cerebral ischemia, and medical complications (fever, anemia, and hyperglycemia). Management also probably is optimized by neurologic intensive care units and multidisciplinary teams.

Descriptive Study of Aneurysmal and Nonaneurysmal Subarachnoid Hemorrhage and the Role of Confirmative Digital Subtraction Angiography in Patients with Nonaneurysmal Subarachnoid in Puerto Rico

BACKGROUND

Cerebrovascular disease is the fifth cause of mortality in Puerto Rico. There is no descriptive study for the presentation of spontaneous subarachnoid hemorrhage (SAH) in our institution. Therefore, our primary aim was to perform a retrospective analysis of adult patients with spontaneous SAH and assess the need for digital subtraction angiography (DSA) after initially aneurysm-negative computed tomography angiography (CTA) in nonaneurysmal SAH, specifically perimesencephalic SAH (PM-SAH).

METHODS

Medical records of 324 adult patients with aneurysmal and nonaneurysmal SAH treated at the Puerto Rico Medical Center from 2015 to 2018 were retrospectively analyzed. Demographics, past medical history, clinical characteristics, and imaging information were extracted.

RESULTS

Acute hydrocephalus, mortality at 30 days, prevalence of diffuse SAH pattern, and Fisher and World Federation of Neurosurgical Societies grades >2 on initial examination were higher in the aneurysmal SAH subgroup. Patients with nonaneurysmal SAH had a significantly higher prevalence of chronic kidney disease and diabetes mellitus. Of the patients with nonaneurysmal PM-SAH with initial aneurysm-negative CTA, 100% were subsequently confirmed by DSA.

CONCLUSIONS

Patients in the aneurysmal SAH subgroup correlated with an increased disease burden. Furthermore, this study shows that in our population, patients with nonaneurysmal PM-SAH with a low Fisher and World Federation of Neurosurgical Societies grade and with comorbid diabetes mellitus and chronic kidney disease may not need DSA after a negative initial CTA result.

Recurrent Bleeding After Perimesencephalic Hemorrhage: Case Report and Review of the Literature

BACKGROUND

Perimesencephalic hemorrhage (PMH), a subtype of nonaneurysmal subarachnoid hemorrhage, is characterized by a typical pattern of localized hemorrhage on head computed tomography. PMH is usually associated with a benign clinical course, and a lower incidence of complications such as vasospasm and rebleeding.

CASE DESCRIPTION

We present the cases of a man aged 28 years and a woman aged 21 years with no relevant medical history who experienced recurrent, spontaneous episodes of PMH within the course of 7 days and 29 months. No precipitating causes were identified.

CONCLUSIONS

There are only a couple of case reports of recurrent PMH, some of which were defined questionably. We review the reported cases and discuss the possible causes and long-term outcomes. Neurointerventionalists and neurosurgeons should be aware that the risk of recurrent hemorrhage of PMH does exist, although it is rather low. Even after early or late rebleeding, prognosis of PMH is excellent.

Recurrent Bleeding After Perimesencephalic Hemorrhage

BACKGROUND

Perimesencephalic hemorrhage (PMH) is a type of subarachnoid hemorrhage with excellent long-term outcomes. Only 1 well-documented case of in-hospital rebleeding after PMH is described in the literature, which occurred after initiating antithrombotic treatment because of myocardial ischemia. We describe a patient with PMH without antithrombotic treatment who had 2 episodes of recurrent bleeding on the day of ictus. To validate the radiologic findings, we conducted a case-control study. Six neuroradiologists and 2 neuroradiology fellows performed a blinded assessment of serial unenhanced head computed tomography (CT) scans of 8 patients with a perimesencephalic bleeding pattern (1 index patient, 6 patients with PMH, 1 patient with perimesencephalic bleeding pattern and basilar artery aneurysm) to investigate a potential increase in amount of subarachnoid blood.

CASE DESCRIPTION

A 56-year-old woman with a perimesencephalic bleeding pattern and negative CT angiography had 2 episodes after the onset headache with a sudden increase of the headache. Blinded assessment of serial head CT scans of 8 patients with a perimesencephalic bleeding pattern identified the patient who was clinically suspected to have 2 episodes of recurrent bleeding to have an increased amount of subarachnoid blood on 2 subsequent CT scans.

CONCLUSIONS

Recurrent bleeding after PMH may also occur in patients not treated with antithrombotics. Even after early rebleeding, the prognosis of PMH is excellent.

Cost-effectiveness Analysis of Follow-up Strategies for Thunderclap Headache Patients With Negative Noncontrast CT

OBJECTIVES

Accurate diagnosis of acute subarachnoid hemorrhage (SAH) is critical in thunderclap headache patients due to high morbidity and mortality associated with missed aneurysmal bleeds. The objective of this study was to determine the utility of computed tomography angiography (CTA) in managing patients with acute, severe headaches and negative noncontrast CT and assess the cost-effectiveness of three different screening strategies-no follow up, CTA, and lumbar puncture (LP).

METHODS

A modeling-based economic evaluation was performed with a time horizon of 1 year for thunderclap headache patients in the emergency department with negative noncontrast CT for SAH. Sensitivity analyses were performed to determine the effect of sensitivity of CT and the prevalence of SAH on cost-effectiveness.

RESULTS

Lumbar puncture follow-up has the lowest cost and the highest utility in the mathematical model. The Monte Carlo simulation shows noncontrast CT with LP follow-up to be the most cost-effective strategy in 85.3% of all cases even at a $1 million/quality-adjusted life-years willingness-to-pay. Sensitivity analyses demonstrate that LP follow-up should be performed, except for when CT sensitivity exceeds 99.2% and the SAH prevalence is below 3.2%, where no follow-up may be considered.

CONCLUSIONS

Although CTA is frequently used for evaluation of thunderclap headache patients, its utility is not clearly defined. LP follow-up is shown to be the most cost-effective strategy for evaluation of thunderclap headache patients in most clinical settings.

Use of Follow-Up Imaging in Isolated Perimesencephalic Subarachnoid Hemorrhage

Background and Purpose—

Multiple studies have shown that negative computed tomographic angiograms (CTAs) are reliable in excluding aneurysms in patients with isolated perimesencephalic subarachnoid hemorrhage (pSAH). We evaluate the use of digital subtraction angiography versus CTA for initial diagnosis and of angiographic follow-ups in patients with pSAH by performing an institutional analysis and a meta-analysis of literature.

Methods—

Retrospective institutional analysis of patients with pSAH was performed from 2008 to 2014. The number and types of follow-up imaging studies were tabulated. Initial and follow-up studies were evaluated by an experienced neuroradiologist for intracranial aneurysm. Meta-analysis of literature was performed to assess the use of initial digital subtraction angiography and of follow-up imaging.

Results—

Our institutional review revealed no additional use of initial digital subtraction angiography or of any angiographic follow-up after initial negative CTA in patients with pSAH on noncontrast CT. Meta-analysis of 40 studies yielded a total of 1031 patients. Only 8 aneurysms were first diagnosed on follow-ups (0.78%). Careful review showed that some of these aneurysms reported on follow-up are of questionable validity. Initial digital subtraction angiography and follow-up imaging after a negative initial CTA showed no statistically significant benefits.

Conclusions—

In patients meeting the strict imaging criteria of pSAH, initial negative CTA is reliable in excluding aneurysms. A critical review of the literature through meta-analysis shows no foundation for multiple follow-up studies in patients with pSAH.