The Cost-Utility of CT Angiography and Conventional Angiography for People Presenting with Intracerebral Hemorrhage

<div><p>Objective</p><p>To determine the optimal imaging strategy for ICH incorporating CTA or DSA with and without a NCCT risk stratification algorithm.</p><p>Methods</p><p>A Markov model included costs, outcomes, prevalence of a vascular lesion, and the sensitivity and specificity of a risk stratification algorithm from the literature. The four imaging strategies were: (a) CTA screening of the entire cohort; (b) CTA only in those where NCCT suggested a high or indeterminate likelihood of a lesion; (c) DSA screening of the entire cohort and (d) DSA only for those with a high or indeterminate suspicion of a lesion following NCCT. Branch d was the comparator.</p><p>Results</p><p>Age of the cohort and the probability of an underlying lesion influenced the choice of optimal imaging strategy. With a low suspicion for a lesion (<12%), branch (a) was the optimal strategy for a willingness-to-pay of $100,000/QALY. Branch (a) remained the optimal strategy in younger people (<35 years) with a risk below 15%. If the probability of a lesion was >15%, branch (b) became preferred strategy. The probabilistic sensitivity analysis showed that branch (b) was the optimal choice 70–72% of the time over varying willingness-to-pay values.</p><p>Conclusions</p><p>CTA has a clear role in the evaluation of people presenting with ICH, though the choice of CTA everyone or CTA using risk stratification depends on age and likelihood of finding a lesion.</p></div

Base Case graphs.

<p>The base case analyses are presented on a two-dimensional graph showing the net costs and net QALYs for CTA of the entire cohort (diamond), CTA for high or indeterminate suspicion of a lesion on NCCT (square), DSA for the entire cohort (asterisk) and DSA for those with a high or indeterminate suspicion of a lesion on NCCT (triangle).</p

Influence Diagram.

<p>The health states following presentation with primary ICH or secondary ICH are depicted.</p

Probabilistic sensitivity analysis.

<p>Variables in the model were sampled simultaneously to show the probability that a given strategy was optimal strategy in relation to the willingness-to-pay (x-axis) using net monetary benefits calculations.</p

Model inputs.

<p>The range presented is for the one-way sensitivity analysis. The relative risk is for re-bleed after the lesion is fixed. CTA = CT Angiography; DSA = digital subtraction angiogram; ICH = intracerebral hemorrhage; mRS  =  modified Rankin Scale score; NCCT = non-contract head CT; PSA = probabilistic sensitivity analysis; RR = relative risk; USD = United States Dollars.</p

One way sensitivity analysis for the probability of a lesion in a 40-year old cohort.

<p>Bold: The strategy is dominant (less costly and more QALYs than the comparator). Normal: The ICER falls in an acceptable range. Italics: Not optimal - the strategy is dominated, in the southwest quadrant, or in the northwest quadrant above the $100,000 per QALY line.</p

Two-way sensitivity analysis.

<p>The prevalence of a lesion and cohort age were tested in a two-way deterministic sensitivity analysis with a willingness-to-pay of $100,000/QALY. The optimal imaging strategy - CTA of the entire cohort (blue), CTA for high or indeterminate suspicion of a lesion on NCCT (orange) and DSA for a high or indeterminate suspicion of a lesion on NCCT (green) – depends on the age and probability of a lesion.</p