Introduction: The optimal management strategies for unruptured intracranial aneurysms and brain arteriovenous malformations (AVMs) are topics of significant debate. The decision to treat these unruptured cerebrovascular (CV) lesions involves acceptance of an upfront treatment-associated risk of morbidity and mortality (M&M) in return for relative lifelong proctection from hemorrhage and its associated M&M, whereas a decision for observation avoids the upfront risk of interventional treatment in favor of a small but perpetual risk of M&M. This decision is influenced by both objective and subjective elements that are unique to an individual patient. The purpose of this study was to create a nomogram to assist neurosurgeons, neurointerventionalists, radiation oncologists, and neurologists in this decision-making process.
Methods: A novel graphical tool was founded on a Markov model of a theoretical patient with an unruptured CV lesion. The model weighs the considerations of patient age and life expectancy (LE) against the morbidity and mortality of lesion hemorrhage and the morbidity and mortality of intervention based on published data. The subjective factors of a patient’s aversion to upfront risk and anxiety level are optionally included.
Results: The tool allows clinicians to apply to an individual patient the published data on demographically-adjusted life expectancy, the risk of CV lesion observation, and the risk of interventional treatment. The graphical format of the tool de-emphasizes the search for an “optimal” decision, and highlights those factors where clinical judgment must play the key role.
Conclusions: The tool identifies which data-specific and patient-specific factors are more influential in the decision-making process and aides CV practitioners in guiding treatment decisions for unruptured lesions.
Patient Care: The decision to treat certain unruptured cerebrovasculuar (CV) lesions is clinically debatable and multiple factors contribute to a neurosurgeon's recommendation to treat and a patient's acceptance of the treatment plan. This novel graphical model utilizes published data on CV lesion risk and treatment-associated risk in addition to subjective patient factors to contruct a "critical horizon" for treatment to help this decision making process. The model relies on an accurate estimation of a patient's life expectancy given certain demographic factors as well as literature data on CV lesion hemorrhage risk and treatment risk. By combining all factors into a single tool, a decision to treat or not to treat can be reached by simultaneously analyzing all presented factors.
Learning Objectives: By the conclusion of this session, participants should be able to:
1) Discuss the variables that contribute to cerebrovascular (CV) lesion morbidity and mortality.
2) Differentiate between the law of multiplicativity for the accumulation of risk of CV lesion hemorrhage and the accrual of potential for M&M in the presented nomogram.
3) Use the graphical tool to help in decision making processes for unruptured intracranial aneurysms and brain arteriovenous malformations.