Rationale and Objectives
The study goal was to evaluate the cost-effectiveness of surgery and endovascular treatment of unruptured intracranial aneurysms in patients with a history of subarachnoid hemorrhage from a previous aneurysm, incorporating the results of the prospective International Study of Unruptured Intracranial Aneurysms.
Materials and Methods
Using a Markov model, we performed a decision and cost-effectiveness analysis comparing surgery or endovascular treatment with no treatment. Twelve clinical scenarios were defined based on aneurysm size and location. Probabilistic sensitivity analyses were performed for 50- and 40-year-old cohorts. Treatment was considered to be cost-effective at an incremental cost-effectiveness ratio less than $100,000 per quality-adjusted life-year.
Results
In 50-year-old patients, no treatment was the most cost-effective strategy for aneurysms located in the cavernous carotid artery. For aneurysms less than 7 mm located in the anterior circulation, no treatment was the most cost-effective strategy. Endovascular treatment was the most cost-effective option for 7- to 24-mm aneurysms, whereas surgery was the most cost-effective option for aneurysms of 25 mm or larger. For aneurysms less than 7 mm and located in the posterior circulation, endovascular treatment was the most cost-effective option, whereas surgery was the most cost-effective option for 7- to 12-mm aneurysms. No treatment was the most cost-effective strategy for aneurysms of 13 mm or larger.
Conclusion
For 50-year-old patients with a history of aneurysmal subarachnoid hemorrhage, treatment of unruptured aneurysms that are located in the cavernous carotid artery, or small (<7 mm) and located in the anterior circulation, or large (≥13 mm) and located in the posterior circulation is ineffective or not cost-effective.
Most cases of subarachnoid hemorrhage (SAH) are caused by ruptured intracranial aneurysms. Unruptured intracranial aneurysms are relatively common, affecting up to 2% to 5% of the population ( ). The management of unruptured intracranial aneurysms depends on the natural history of these lesions and on morbidity and mortality rates associated with their repair. There is still controversy about the management of unruptured intracranial aneurysms ( ). In 2003, the International Study of Unruptured Intracranial Aneurysms (ISUIA) investigators reported prospective data on the natural history and treatment outcomes of unruptured intracranial aneurysms ( ). Aneurysm rupture rates varied depending on aneurysm size and location, and treatment outcomes depended on patient age and aneurysm size and location ( ). Patients with a history of SAH from a previous aneurysm had a higher risk of aneurysm rupture than patients without a history of SAH ( ). In addition, patients with a history of aneurysmal SAH have a higher mortality rate than the general population even after successful treatment of ruptured aneurysms ( ). Previous decision and cost-effectiveness analyses were based on earlier estimates of rupture and complication rates and did not consider these factors in their models ( ). Most analyses evaluated the effectiveness or cost-effectiveness of treatment of unruptured intracranial aneurysms only in patients without a history of SAH ( ). The purpose of our study was to evaluate the cost-effectiveness of surgery and endovascular treatment of unruptured intracranial aneurysms in patients with a history of SAH from a previous aneurysm, incorporating the results of the prospective ISUIA ( ).
Materials and methods
Study Design
We performed a decision and cost-effectiveness analysis from the societal perspective in which we simulated the clinical paths and health states that patients with a history of SAH from a previous aneurysm would traverse having undergone or not undergone surgery or endovascular treatment for unruptured intracranial aneurysms ( ). Although standard practice in cost-effectiveness analysis is to compare each treatment to the next best option, we chose to compare both treatments to no treatment as our aim in this study was to decide which unruptured intracranial aneurysms should be treated. We assumed that a previous ruptured aneurysm was completely obliterated after the first SAH and that the patient was well (not disabled). Patients with a history of SAH from a previous aneurysm have a higher risk of aneurysm rupture than patients without a history of SAH ( ). Aneurysm rupture rates vary depending on aneurysm size and location ( ). To account for variable aneurysm characteristics, we modeled 12 different clinical scenarios.
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The Markov Model
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Table 1
Probabilities
Baseline Range Source Aneurysm rupture rates (per y), % ISUIA, 2003 ( ) Cavernous carotid artery aneurysms <7 mm 0 — 7–12 mm 0 — 13–24 mm 0.6 0.1–2.0 ⁎ ≥25 mm 1.3 0.1–5.3 ⁎ Anterior communicating or anterior cerebral artery/middle cerebral artery/internal carotid artery aneurysms <7 mm 0.3 0.1–0.6 ⁎ 7–12 mm 0.5 0.3–0.9 ⁎ 13–24 mm 3.1 2.1–4.4 ⁎ ≥25 mm 9.7 6.9–13.3 ⁎ Posterior circulation/posterior communicating artery aneurysms <7 mm 0.7 0.3–1.4 ⁎ 7–12 mm 3.1 2.0–4.5 ⁎ 13–24 mm 4.0 2.4–6.2 ⁎ ≥25 mm 12.9 8.5–18.7 ⁎ Relative risks of mortality No disability after SAH Cohort study ( ) Age, 4–39 6.3 4.4–9.0 Age, 40–54 2.4 1.8–3.2 Age, 55+ 1.3 1.0–1.7 Disability after SAH Cohort study ( ) Age, 4–44 8.7 7.1–10.6 Age, 45–54 5.4 4.5–6.5 Age, 55+ 3.4 2.9–3.8
ISUIA, International Study of Unruptured Intracranial Aneurysms; SAH, subarachnoid hemorrhage.
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Outcome Measures
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Analyses Performed
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Results
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Table 2
Effectiveness, Cost, and Cost-Effectiveness Compared with No Treatment for 50-Year-Old Patients with a History of Subarachnoid Hemorrhage from a Previous Aneurysm
QALYs Cost, $ Incremental Cost per QALY, $ Average Incremental (95% CI) Average Incremental (95% CI) A) Cavernous carotid artery aneurysm, <7 mm No treatment 18.2 0 Surgery 16.7 −1.6 (−2.1, −1.1) 45,800 45,800 (34,200, 59,900) Ineffective Endovascular treatment 17.3 −1.0 (−1.7, −0.5) 33,200 33,200 (24,000, 44,800) Ineffective B) Cavernous carotid artery aneurysm, 7−12 mm No treatment 18.2 0 Surgery 16.6 −1.6 (−2.1, −1.1) 45,500 45,500 (34,100, 59,300) Ineffective Endovascular treatment 17.2 −1.0 (−1.7, −0.5) 33,200 33,200 (23,900, 44,900) Ineffective C) Cavernous carotid artery aneurysm, 13−24 mm No treatment 16.5 8,800 Surgery 14.9 −1.6 (−3.2, 0.6) 61,300 52,400 (29,000, 73,400) Ineffective Endovascular treatment 16.7 0.2 (−1.3, 1.7) 38,200 29,300 (14,700, 43,700) 142,100 D) Cavernous carotid artery aneurysm, ≥25 mm No treatment 15.7 16,500 Surgery 14.0 −1.8 (−4.5, 2.3) 70,000 53,600 (12,400, 84,700) Ineffective Endovascular treatment 15.6 −0.07 (−2.2, 2.2) 46,800 30,300 (7,600, 50,800) Ineffective E) Anterior circulation aneurysm, <7 mm No treatment 16.8 5,000 Surgery 16.7 −0.2 (−1.3, 0.9) 45,600 40,700 (28,500, 55,100) Ineffective Endovascular treatment 17.0 0.2 (−0.9, 1.3) 35,100 30,100 (20,400, 41,800) 146,300 F) Anterior circulation aneurysm, 7−12 mm No treatment 16.5 8,400 Surgery 16.6 0.1 (−0.9, 1.3) 45,500 37,100 (24,600, 51,300) 267,300 Endovascular treatment 16.9 0.4 (−0.7, 1.5) 36,400 27,900 (18,100, 40,000) 69,200 G) Anterior circulation aneurysm, 13−24 mm No treatment 13.5 38,700 Surgery 14.9 1.4 (−0.3, 3.2) 61,400 22,700 (3,300, 42,900) 16,400 Endovascular treatment 15.3 1.8 (0.5, 3.0) 51,700 13,000 (−100, 26,800) 7,400 H) Anterior circulation aneurysm, ≥25 mm No treatment 9.8 73,000 Surgery 13.9 4.1 (1.6, 6.7) 70,200 −2,900 (−31,100, 24,600) −700 Endovascular treatment 12.1 2.3 (0.7, 3.9) 79,300 6,300 (−9,800, 22,900) 2,700 I) Posterior circulation aneurysm, <7 mm No treatment 16.3 10,800 Surgery 16.5 0.2 (−1.4, 1.8) 46,700 35,900 (18,900, 54,500) 146,900 Endovascular treatment 16.6 0.4 (−1.4, 1.7) 38,800 27,900 (15,100, 44,300) 78,100 J) Posterior circulation aneurysm, 7−12 mm No treatment 13.5 38,600 Surgery 16.5 3.0 (1.1, 4.9) 46,600 8,100 (−13,200, 28,900) 2,700 Endovascular treatment 15.3 1.8 (0.1, 3.2) 51,400 12,800 (−1,100, 28,200) 7,200 K) Posterior circulation aneurysm, 13−24 mm No treatment 12.8 45,600 Surgery 12.5 −0.3 (−3.2, 2.6) 83,100 35,500 (7,000, 71,500) Ineffective Endovascular treatment 13.0 0.2 (−2.4, 2.2) 69,400 23,800 (5,000, 47,400) 136,400 L) Posterior circulation aneurysm, ≥25 mm No treatment 9.0 80,500 Surgery — — — — — Endovascular treatment 8.7 −0.3 (−2.5, 1.8) 103,800 23,300 (3,900, 45,900) Ineffective
CI, confidence interval; QALY, quality-adjusted life-year.
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Table 3
Effectiveness, Cost, and Cost-Effectiveness Compared with No Treatment for 40-Year-Old Patients with a History of Subarachnoid Hemorrhage from a Previous Aneurysm
QALYs Cost, $ Incremental Cost per QALY, $ Average Incremental (95% CI) Average Incremental (95% CI) A) Cavernous carotid artery aneurysm, <7 mm No treatment 21.2 0 Surgery 20.3 −0.9 (−1.3, −0.6) 39,800 39,800 (29,300, 53,100) Ineffective Endovascular treatment 20.0 −1.3 (−2.5, −0.5) 35,700 35,700 (25,000, 50,300) Ineffective B) Cavernous carotid artery aneurysm, 7−12 mm No treatment 21.2 0 Surgery 20.3 −0.9 (−1.3, −0.6) 39,700 39,700 (29,200, 52,500) Ineffective Endovascular treatment 19.9 −1.3 (−2.5, −0.5) 35,600 35,600 (24,800, 50,300) Ineffective C) Cavernous carotid artery aneurysm, 13−24 mm No treatment 19.0 11,100 Surgery 20.5 1.5 (−0.2, 4.1) 37,900 26,700 (1,900, 44,900) 17,900 Endovascular treatment 19.9 0.9 (−1.1, 2.7) 36,600 25,500 (8,900, 43,400) 29,100 D) Cavernous carotid artery aneurysm, ≥25 mm No treatment 18.0 20,400 Surgery 17.7 −0.4 (−4.6, 5.2) 64,700 44,300 (−7,700, 86,800) Ineffective Endovascular treatment 17.6 −0.4 (− 5.0, 2.9) 54,900 34,400 (4,500, 72,800) Ineffective E) Anterior circulation aneurysm, <7 mm No treatment 19.5 6,200 Surgery 20.3 0.8 (−0.4, 2.0) 39,800 33,500 (21,800, 47,000) 42,300 Endovascular treatment 19.7 0.2 (−1.4, 1.5) 37,900 31,700 (20,400, 45,800) 181,000 F) Anterior circulation aneurysm, 7−12 mm No treatment 19.1 10,700 Surgery 20.3 1.3 (0.0, 2.6) 39,800 29,100 (15,800, 43,300) 23,100 Endovascular treatment 19.5 0.5 (−1.1, 1.8) 39,600 28,900 (17,500, 43,500) 63,300 G) Anterior circulation aneurysm, 13−24 mm No treatment 15.2 46,700 Surgery 20.5 5.3 (3.4, 7.4) 37,800 −8,900 (−31,200, 11,500) −1,700 Endovascular treatment 18.0 2.8 (1.0, 4.3) 53,800 7,100 (−8,000, 23,600) 2,600 H) Anterior circulation aneurysm, ≥25 mm No treatment 10.9 84,100 Surgery 17.7 6.8 (2.9, 10.2) 64,600 −19,500 (−55,300, 19,200) −2,900 Endovascular treatment 13.3 2.4 (−0.9, 4.6) 91,800 7,700 (−12,800, 33,900) 3,300 I) Posterior circulation aneurysm, <7 mm No treatment 18.8 13,500 Surgery 19.4 0.6 (−1.4, 2.6) 48,400 34,900 (16,200, 56,300) 55,600 Endovascular treatment 18.8 0.004 (−2.9, 1.9) 45,600 32,100 (15,900, 57,500) 8,750,500 J) Posterior circulation aneurysm, 7−12 mm No treatment 15.2 46,500 Surgery 19.4 4.2 (1.9, 6.5) 48,300 1,900 (−22,100, 25,900) 400 Endovascular treatment 17.1 1.8 (−0.8, 3.7) 60,600 14,200 (−3,300, 36,100) 7,700 K) Posterior circulation aneurysm, 13−24 mm No treatment 14.3 54,800 Surgery 16.7 2.4 (−2.0, 6.2) 73,400 18,700 (−18,700, 64,300) 7,700 Endovascular treatment 15.7 1.3 (−4.4, 4.2) 72,000 17,200 (−7,500, 63,200) 12,900 L) Posterior circulation aneurysm, ≥25 mm No treatment 10.0 92,000 Surgery 14.4 4.4 (0.9, 7.9) 95,500 3,500 (−33,000, 41,800) 800 Endovascular treatment — — — — —
CI, confidence interval; QALY, quality-adjusted life-year.
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Table 4
Summary of Results of Probabilistic Sensitivity Analyses
Age, 50 y Age, 40 y Surgery Endovascular Treatment Surgery Endovascular Treatment Cavernous carotid artery aneurysm A) <7 mm — — — — B) 7−12 mm — — — — C) 13−24 mm — — O O D) ≥25 mm — — — — Anterior circulation aneurysm E) <7 mm — — O — F) 7−12 mm — O O O G) 13−24 mm O O O O H) ≥25 mm O O O O Posterior circulation aneurysm I) <7 mm — O O — J) 7−12 mm O O O O K) 13−24 mm — — O O L) ≥25 mm — — O —
O indicates that the strategy was cost-effective (incremental cost-effectiveness ratio <$100,000 per quality-adjusted life-year) compared with no treatment.
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Discussion
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Conclusion
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