Saurabh Jha MD, Presenter: Nothing to Disclose

Radiation dose and proportion of negative coronary catheter angiograms (CCA) are potential quality metrics in the management of patients with suspected chronic stable angina. The tension between achieving the metrics when using various gatekeeper tests for coronary artery disease (CAD) is explored.

Decision model capturing the diagnostic strategies utilizing various gatekeeper tests, either singly or in combination, in a cohort of patients suspected of chronic stable angina was constructed. CCA was assumed to be the gold standard. Patients with positive and non-diagnostic tests were assumed to receive CCA. The outcomes included total radiation dose in the diagnostic pathway and the proportion of negative catheter angiograms. The pre-test probability of obstructive CAD in the base case was determined by the model of Diamond and Forrester that uses age, sex and nature of chest pain. The gatekeeper tests included exercise ECG, stress echocardiogram, stress MRI, SPECT, cardiac CT and PET. The test characteristics, equivocal test rate and mean radiation dose were abstracted from the literature. It was assumed that desired quality was the minimization of both radiation dose and proportion of negative catheter angiograms.  

The typical patient in the cohort is a 55 year old female with atypical chest pain who has 30 % pre-test probability of obstructive CAD. Cardiac CT achieved one of the lowest negative CCA rate of 33 % (desirable) but the highest radiation dose of 15.04 msv (undesirable). Exercise ECG led to the highest negative CCA rate (undesirable) of 54 % but one of the lowest radiation doses (desirable) of 3.36 msv. A combination of stress echo followed by cardiac CT for the non-diagnostic tests was optimal achieving a negative CCA rate of 26 % and a radiation exposure of 3.93 msv.  

A strategy employing stress echo and cardiac CT achieved the lowest negative CCA rate and relatively low radiation exposure; both outputs are plausible quality metrics. The scenario highlights that quality metrics can sometimes be oppositional, even if united by a singular underlying goal of improved patient care.

Metrics will become ubiquitous in adjudicating quality and determining value and reimbursement in healthcare.

Jha, S, Tension between Quality Metrics: The Case of Radiation Dose and Diagnostic Yield in Suspected Chronic Stable Angina.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13027911.html