Coronary artery disease
Three-Year Outcomes and Cost Analysis in Patients Receiving 64-Slice Computed Tomographic Coronary Angiography for Chest Pain

https://doi.org/10.1016/j.amjcard.2009.04.011Get rights and content

Sixty-four slice computed tomographic coronary angiography (CTCA) is being used more often in the evaluation of patients with chest pain. The strength of this test is its high specificity and negative predictive value in exclusion of coronary artery disease (CAD). Its use remains controversial because there are theoretical risks of radiation, additional costs of the test, and no long-term data to suggest that excluding CAD by use of this test results in positive patient outcomes. A total of 436 patients underwent 64-slice CTCA because of chest pain thought to be anginal. Cardiac computed tomography was ordered by the primary physician or cardiologist based on a low to intermediate pretest probability of flow-limiting CAD. A smaller subset of patients initially underwent stress testing but had equivocal findings or continued symptoms that warranted further evaluation. Of the total patient cohort, 376 had “no significant CAD” based on computed tomographic coronary angiographic results. Of the 60 patients who were believed on computed tomographic coronary angiogram to have “flow-limiting” CAD, 34 (57%) ended up having percutaneous coronary intervention or coronary artery bypass grafting. The remaining 26 patients (43%) did not have true flow-limiting disease on coronary catheterization and were treated medically. With follow-up of 36 months, 376 of those patients (100%) with minimal or no disease by CTCA were free of events or intervention. In conclusion, in a real-world, clinical setting, the negative predictive value of low-risk CTCA is very high and exceptionally helpful in predicting freedom from events for up to 3 years. By avoiding further invasive treatments, there is a significant potential cost savings in patients who are sent for noninvasive coronary angiography rather than invasive angiography.

Section snippets

Methods

A total of 436 consecutive patients were identified who had undergone 64-slice CTCA during 1 year (June 2005 through June 2006) for a diagnosis of chest pain. Coronary CTCA was performed with a 64-slice GE LightSpeed VCT scanner (GE Healthcare, Milwaukee, Wisconsin). Patients were pretreated with an intravenous β blocker or a calcium channel blocker to achieve a heartbeat <65 beats/min. Radiation exposure averaged 12 mSv. All scans were read by an experienced reader with at least level 2

Results

Of the 436 patients, 376 patients were found to have “no significant CAD” based on computed tomographic coronary angiographic results. Of the patients who were believed on computed tomographic coronary angiogram to have “flow-limiting” CAD (60 patients), 57% (34) ended up having PCI or CABG (“true” positive scan).

Although most patients underwent CTCA as their first test, a subgroup of 78 patients (18%) underwent stress testing before computed tomography. No patient had a strongly positive

Discussion

A recent study of 100 consecutive patients undergoing 64-slice CTCA for chest pain with no previous CAD and a nondiagnostic stress test finding revealed a 90% positive predictive value in detecting obstructive CAD.2 A similar study of 145 patients comparing 64-slice CTCA with myocardial perfusion testing revealed a sensitivity of 98%, specificity of 74%, positive predictive value of 90%, and negative predictive value of 94% for CTCA. The investigators concluded that, in patients with suspected

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