Author: Gabriela Espinosa Garcia Lorenzana, B.S.
Primary Advisor: Sriram M. Iyengar, PhD
Committee Members: Jorge R. Herskovic, MD, PhD
Masters thesis, The University of Texas School of Biomedical Informatics at Houston.
Abstract:
Purpose
To evaluate and compare the cost-effectiveness of coronary computed tomography diagnostic strategies for adults with acute chest pain without known coronary artery disease (CAD) in the assessment of a novel blood pool iodine-based contrast agent that reduces the risk of contrast-induced nephropathy (CIN) for an eligible population consisting of individuals undergoing invasive coronary angiography.
Materials-and-Methods
A decision analysis model was built in order to determine and compare the cost-effectiveness of a blood pool contrast agent (BPCA) and conventional iodine agents for computed tomography angiography (CTA) in diagnosing patients with acute chest pain. The model was used to evaluate three unique diagnostic strategies: BPCA-CTA followed by invasive coronary angiography (ICA), conventional CTA followed by ICA and ICA alone. Analyses were done from a payer perspective for a one-year diagnostic period. The base case population was defined as 55-year-old males with unknown history of CAD, negative initial biomarkers and negative or inconclusive ECG. The prevalence of CAD was set as a baseline value of 30% and the CIN risk was estimated at 11%. Extensive sensitivity analyses were performed for all relevant variables.
Results
The use of any of the two CTA-based triage tests before ICA for a prevalence of CAD of less than 47%, resulted more cost-effective than diagnosing with ICA alone. By using the base case values and a cost premium of BPCA per dose of $150 over the conventional CT agent (~5x), BPCA-CTA prior to ICA resulted in the most cost effective strategy, ruling out the other strategies by simple dominance. The model heavily depends on the complication rates of the diagnostic tests included in the model. In the case of a population with a risk of CIN of 20%, a cost of up to $600 per BPCA dose would still make the BPCA-CTA alternative more cost effective than conventional CTA. A similar effect is observed for the potential complications resulting from the BPCA injection. Given the base case scenario, if the complication rate of BPCA (from infusion reactions) were to lie above ~6%, the conventional CTA diagnostic strategy would result as the optimal alternative.
Conclusions
The decision to use a blood pool contrast agent (BPCA) over conventional agents for CTA largely depends on the presence of CIN from conventional agents as well as the risk of experiencing infusion reactions from BPCA in the target population. BPCAs could have a great impact in the diagnosis of acute chest pain, in particular for populations with high incidences of CIN. In addition, a BPCA strategy could accrue more savings if other excluded phenomena such as “renalism” and incidental findings had been included in the decision model.