Abstract
Background
Coronary computed tomography angiography (CTA) has high diagnostic accuracy in ruling out significant stenosis of coronary arteries in patients with intermediate probability of coronary artery disease. Based on CTA result, some patients are scheduled for invasive coronary angiography (ICA). As no specyfic guidelines exist for such situations, during ICA contrast media is routinely injected into both coronary arteries, irrespectively of CTA result. Conceivably, patients scheduled for ICA with one vessel disease may benefit from invasive interrogation limited to the diseased vessel only, presumably resulting in less contrast, lower radiation dose and less complications related to catheterization.
Purpose
The aim of this study was to analyse the potential trade-off between the benefits and costs of a “diseased-vessel-only” (>50% DS in CTA) invasive diagnostic approach in patients undergoing ICA following coronary CTA, as compared to the traditional “total ICA” (including both arteries regardless of CTA result) approach. The potential benefits were defined as contrast and radiation doses reduction during ICA and the costs were defined as missing significant coronary stenosis.
Methods
In 85 patients who underwent CTA and subsequently ICA we precisely measured contrast volume and radiation dose used to visualise each vessel during ICA. Then we proposed excluding a vessel (either left or right coronary artery) without >50% diameter stenosis in CTA from ICA, and studied how it would affect ICA contrast and radiation values. DS in CTA and ICA were assessed quantitatively.
Results
CTA sensitivity, specificity, positive predictive value and negative predictive value in diagnosing >50%DS as assessed by ICA were 95.2%, 96.2%, 91.6% and 97.9%, respectively. Applying <50% DS in CTA as a threshold not to visualise the artery during ICA would reduce contrast volume by 47% (27ml, Fig. 1) and radiation dose by 51% (3.14mSv, Fig.2, both p<0.0001). No significant (>50%DS in ICA) stenosis would be missed by CTA.
Figures 1 and 2
Conclusion
These real-world data support the concept that vessels with <50%DS in CTA do not need to be visualised during ICA. Such approach would result in significant reduction in contrast media volume and patient's exposure to radiation during ICA, without underdiagnosing any of the patients.
Radiation Dose Reduction Comparing Dual Axis Rotational Coronary Angiography against Conventional Coronary Angiography in a Population with 100% Suspected Coronary Artery Disease: A Randomized Trial