Ajit S. Puri, MD Assistant Professor of Radiology and Neurosurgery

Co-Director, Division of Neurointerventional Surgery, University of Massachusetts Medical Center

•  Research grant from Stryker Neurovascular •  Research grant from Covidien/ Medtronic •  Consultant and proctor for Stryker Neurovascular •  Consultant and proctor for Covidien/ Medtronic •  Consultant for Codman Neurovascular

•  UIAs are relatively common in the general population, found in ≈3.2% of the adults (mean age 50 years) worldwide, increasingly being discovered incidentally due to use of MRIs.

•  Majority of UIAs will never rupture. •  For example, of the 1 million adults ≈32 000 harbor a

UIA, but only 0.25% of these, or 1 in 200 to 400, will rupture.

•  Women had a higher prevalence of UIAs than men, even after adjustment for age and co-morbidities.

•  Prevalence overall higher in people aged ≥30 years.

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Schievink N Engl J Med 1997; Hop et al. Stroke 1997; Olafsson et al.Neurology 1997; Ellegala/Day 2005

•  Larger UIAs may present with mass effect,

cranial nerve deficits (most commonly a 3rd CN nerve palsy), seizures, motor deficit, or sensory deficit, or they may be detected on imaging for headaches, ischemic disease etc.

•  Small UIAs, <7 mm in diameter, uncommonly

cause aneurysmal symptoms and are the most frequently detected incidentally.

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•  1917 patients underwent clipping, and 451 underwent coiling

•  The combined surgical morbidity and mortality at 1 year was 10.1% for patients without prior SAH and 12.6% for patients with prior SAH versus 7.1% and 9.8%, respectively, for the endovascular group.

•  2575 person-years FU, 33 (23%) of the 142 patients suffered an SAH, an approximate annual incidence of 1.3%, with an average annual incidence of SAH by group of 2.6%, 1%, and 1.3% for symptomatic aneurysm, incidental aneurysm, and prior SAH groups, respectively.

•  UIAs should be treated irrespective of size in the case of patients aged <50 years if it is technically possible and the treatment risk is not compounded by concurrent diseases.

•  January 2001-April 2004, 5720 patients, 20 years of age or older (mean age, 62.5 years; 68% women) with UIAs- 3 mm or more in the largest dimension

•  6697 aneurysms studied, 91% were discovered incidentally.

•  Mean (+/-SD) size- 5.7+/-3.6 mm.

•  During a FU period of11,660 aneurysm-years, ruptures were documented in 111 patients, with an annual rate of rupture of 0.95%

•  Rupture risk increased with size of the aneurysm. •  As compared with MCA aneurysms, PCoM and

ACoM aneurysms were more likely to rupture. •  Aneurysms with a daughter sac (an irregular

protrusion of the wall of the aneurysm)-more likely to rupture

Alshekhlee et al. Stroke 2010

Hospital Mortality and Complications of Electively Clipped or Coiled Unruptured Intracranial

Aneurysms*

•  National Inpatient Sample database 2000-2006 •  Elective admitted to US hospitals with diagnosis

of un-ruptured aneurysms •  3738 clipping •  3498 endovascular coiling •  Basic demographics including race, age, co-

morbidity indices were similar

Alshekhlee et al. Stroke 2010

Clipped Coiled

Length of stay 4 d 1 d P<0.0001

Hospital charges $ 38,166 $ 42,070 P<0.0001

Hospital mortality 1.6% 0.57% OR, 3.63;95% CI,1.57,8.42

Intraprocedural ICH

2.38% 1.37% OR, 1.75;95% CI,1.23,4.49

Postoperative stroke

6.71% 2.92% OR, 2.39;95% CI,1.89,3.03

Composite outcome (death, ICH, stroke)

8.35% 3.69 OR, 2.37;95% CI,1.92,2.93

Endovascular Treatment of Giant Aneurysms: General Principles Robert E. Replogle, MD Operative Techniques in Neurosurgery, V. 8, Iss.2, June 2005, pp67-73.

Endovascular Treatment of Giant Aneurysms: General Principles Robert E. Replogle, MD Operative Techniques in Neurosurgery, V. 8, Iss.2, June 2005, pp67-73.

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It s far more important to know what person the disease has than what disease the person has

Hippocrate

•  Wall shear stress (WSS), is a frictional force of the blood flow that is tangential to the wall.

•  WSS major determinant of vascular remodeling, with values around 20 dynes/cm2, going up to about 200 for an apex and 100 for the distal neck.

•  The anatomical configuration of the arterial tree and the aneurysmal sac determines the hemodynamic stresses in connection with the flow

•  Degradation of the extracellular matrix prominent feature.

•  Quantitative PCR and immunohistochemistry show increased expression of cathepsin in the late stage of aneurysm progression

•  Significant differences between the wall of ruptured and unruptured aneurysms.

•  Macrophage infiltration into the wall may play an important role in weakening the aneurysmal structure

•  Ex vitro at 4.7T of samples- iron deposits as well as fresh/ organizing luminal thrombus.

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Promise as a marker of

inflammation in the vascular

wall

Nicholls et al. Arterioscler Thromb Vasc Biol. 2005

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•  Background: individual patient data from prospective cohort studies to estimate 5-year aneurysm rupture risk.

•  Methods: 8382 participants in six prospective cohort studies with subarachnoid hemorrhage as outcome

Six predictors: age, hypertension, history of SAH, aneurysm size, aneurysm location, geographical region.

•  Endovascular coiling is associated with a reduction in procedural morbidity and mortality over surgical clipping in selected cases but has an overall higher risk of recurrence (Class IIb; Level of Evidence B).

•  Although studies confirm that larger UIA size portends a worse prognosis in terms of bleeding, strict size cutoffs may be less helpful than previously thought.

•  Available data also continue to suggest that UIAs in certain locations, with certain morphological characteristics, are more likely to rupture. It also appears that growth of a UIA is associated with rupture.

•  Reasonable to more strongly consider repair (1) when the UIA is discovered as a result of a prior SAH from a different lesion, (2) if the aneurysm is symptomatic, causing compressive symptoms, or a likely source of otherwise unexplained embolic stroke, or (3) if the patient has a family history of IA.

•  Nonetheless, the risks, benefits, and alternatives to

repair must be considered carefully in each individual case.