Comparing downstream consequences of normal exercise stress echocardiograms and cardiac computed tomography angiography scans in patients suspected of having of obstructive coronary artery disease: a retrospective cohort study of Tricare beneficiaries.

To compare overall number of downstream tests and total costs between negative exercise stress echocardiograms (ESE) or cardiac computed tomography angiography scans (CCTA) in symptomatic Tricare beneficiaries suspected of having coronary artery disease (CAD). This is a retrospective cohort study examining 651 propensity-matched patients who underwent ESE or CCTA with normal results between 2008 and 2014 at the United States' largest Department of Defense hospital. The total number of additional downstream tests over the next five years was determined. The total costs associated with each arm, inclusive of the initial test and all subsequent tests, were calculated using the 2018 Medicare Physician Fee Schedule. 18.5 percent of patients with a normal ESE result underwent some additional form of cardiac testing over the five years after initial testing compared to 12.8 percent of patients with a normal CCTA. The absolute difference in total number of downstream tests between both study groups was 5.7 percent (p = 0.03). When factoring the costs of the initial test as well as the downstream tests, the ESE group was associated with overall lower costs compared to the CCTA group, 351 United States Dollars (USD) versus 496 USD (p < 0.0001). This study demonstrates that, when compared to CCTA, ESE is associated with a higher total number of downstream tests, but overall lower total costs when chosen as initial testing strategy for suspected CAD.

Assessment of Semi-automated Computed Tomographic Measures of Segmental Perfusion Defects in a Swine Model (Sus scrofa) of Intermediate Coronary Lesions.

Computed tomographic myocardial perfusion (CTP) imaging is a tool that shows promise in emergent settings for defining the hemodynamic significance of coronary artery disease. In this study, we examined the accuracy with which the transmural perfusion ratio (TPR) derived through semiautomated CTP analysis reflected segmental perfusion defects associated with intermediate coronary artery lesions in swine. Lesions (diameter stenosis, 65% ± 11%) of the left anterior descending coronary artery (LAD) were created in 10 anesthetized female swine (weight, 47.5 ± 1.9 kg) by using a pneumatic occlusion device implanted on the LAD. Occluder inflation pressures were adjusted to maintain fractional flow reserve (FFR, 74.3 ± 1.7) during adenosine infusion (140ug/kg/min). Static CTP imaging using a stress-rest protocol and segmental TPR derived from semiautomated CT perfusion software was compared with microsphere-derived TPR (mTPR) by using a 16-segment model and polar mapping. Intermediate LAD stenosis was verified through multiplanar coronary CT angiography. Receiver operating characteristic analysis identified an optimal threshold for segmental perfusion defects for intermediate lesions (TPR threshold, ≤0.80); however, the area under the receiver operating characteristic curve was 0.58, and the overall accuracy was 63%. At this threshold, the sensitivity and specificity were 65% and 61%, and the positive and negative predictive values were 61% and 65%, respectively. Although CTP-TPR illustrated segmental perfusion defects with intermediate lesions, the disparity between CTP-TPR and mTPR measures of segmental perfusion suggests that further advances in analysis software may be necessary to improve the localization of segmental defects for intermediated lesions.

Adoption of coronary artery disease - Reporting and Data System (CAD-RADS™) and observed impact on medical therapy and systolic blood pressure control.

BACKGROUND: CAD-RADS was developed to standardize communication of per-patient maximal stenosis on coronary CT angiography (CCTA) and provide treatment recommendations and may impact primary prevention care and resource utilization. The authors sought to evaluate CAD-RADS adoption on preventive medical therapy and risk factor control amongst a mixed provider population. METHODS: Statins, aspirin (ASA), systolic blood pressure and, when available, lipid panel changes were abstracted for 1796 total patients undergoing CCTA in the 12 months before (non-standard reporting, NSR, cohort) and after adoption of the CAD-RADS reporting template. Only initiation of a medication in a treatment naïve patient, escalation from baseline dose, or transition to a higher potency was considered an escalation/initiation in lipid therapy. RESULTS: The CAD-RADS reporting template was utilized in 83.7% (751/897) of CCTAs after the CAD-RADS adoption period. After adjusting for any coronary artery disease (CAD) on CCTA, statin initiation/escalation was more commonly observed in the CAD-RADS cohort (aOR 1.46; 95%CI 1.12-1.90, p = 0.005), driven by higher rates of new statin initiation (aOR 1.79; 95%CI 1.23-2.58, p = 0.002). This resulted in a higher observed rates of total cholesterol improvement in the CAD-RADS cohort (58% vs 49%, p = 0.016). New ASA initiation was similar between reporting templates after adjustment for CAD on CCTA (aOR 1.40; 95%CI 0.97-2.02, p = 0.069). The ordering provider's specialty (cardiology vs non-cardiology) did not significantly impact the observed differences in initiation/escalation of statins and ASA (pinteraction = NS). CONCLUSIONS: Adoption of CAD-RADS reporting was associated with increased utilization of preventive medications, regardless of ordering provider specialty.

Myocardial Assessment with Cardiac CT: Ischemic Heart Disease and Beyond.

PURPOSE OF REVIEW: The aim of this review is to highlight recent advancements, current trends, and the expanding role for cardiac CT (CCT) in the evaluation of ischemic heart disease, nonischemic cardiomyopathies, and some specific congenital myocardial disease states. RECENT FINDINGS: CCT is a highly versatile imaging modality for the assessment of numerous cardiovascular disease states. Coronary CT angiography (CCTA) is now a well-established first-line imaging modality for the exclusion of significant coronary artery disease (CAD); however, CCTA has modest positive predictive value and specificity for diagnosing obstructive CAD in addition to limited capability to evaluate myocardial tissue characteristics. SUMMARY: CTP, when combined with CCTA, presents the potential for full functional and anatomic assessment with a single modality. CCT is a useful adjunct in select patients to both TTE and CMR in the evaluation of ventricular volumes and systolic function. Newer applications, such as dynamic CTP and DECT, are promising diagnostic tools offering the possibility of more quantitative assessment of ischemia. The superior spatial resolution and volumetric acquisition of CCT has an important role in the diagnosis of other nonischemic causes of cardiomyopathies.

The lack of obstructive coronary artery disease on coronary CT angiography safely reduces downstream cost and resource utilization during subsequent chest pain presentations.

OBJECTIVE: The purpose of this study is to investigate the cost and resource use due to chest pain (CP) evaluations after initial coronary CT angiography (CCTA) stratified by coronary artery disease (CAD) burden. METHODS: We examined 1518 patients referred for CCTA from January 2005 to July 2012 for downstream evaluation after CCTA during a median follow-up of 351 days. Results were stratified by CAD burden as quantified on CCTA into no CAD, nonobstructive CAD (<50% stenosis), or obstructive CAD (≥50% stenosis). The incidence of ischemic testing at the time of recurrent evaluation (defined as a composite of clinic visit, emergency department encounter, or ischemic testing after the index CCTA for CP, atypical CP, or angina defined by ICD-9 code), the testing modality used, and frequency of testing were abstracted and used to calculate the direct costs of downstream utilization. Major adverse cardiovascular events defined as all-cause mortality, nonfatal myocardial infarction, stroke, or revascularization >90 days from CCTA were abstracted using ICD-9 codes and Social Security Death Index query. RESULTS: A total of 174 patients (11.5%) underwent evaluation for CP after index CCTA with a higher rate of subsequent clinical visits among obstructive CAD patients compared to those with nonobstructive CAD and no CAD (17.8% vs 13.9% vs. 7.5%; P < .001). A significant reduction in the incidence of repeat ischemic testing was observed in patients with no CAD and nonobstructive CAD (P = .002). This resulted in a lower per-patient cost in the nonobstructive CAD and no CAD patients (median [interquartile range 25-75]: $2952 [$307-2952] and $235 [$0-2880]) when compared with patients with obstructive CAD (median [interquartile range 25-75]: $5832 [$5498-17,459]; P < .001). Major adverse cardiovascular events were not different in the 90 patients that underwent repeat testing at the time of CP evaluation when compared with the 84 patients for whom testing was deferred. CONCLUSION: Absence of CAD on initial CCTA was associated with lower costs and decreased downstream utilization compared to the presence of nonobstructive and obstructive CAD on CCTA during median follow-up of 351 days.

Safe and rapid disposition of low-to-intermediate risk patients presenting to the emergency department with chest pain: a 1-year high-volume single-center experience.

BACKGROUND: Coronary CT angiography (CTA) is a powerful tool for the evaluation of chest pain in the emergency department (ED). Some debate persists regarding its cost-effectiveness in a low-to-intermediate risk population. OBJECTIVE: This study sought to evaluate the safety and cost-effectiveness of coronary CTA for low-to-intermediate risk patients presenting to the ED with chest pain in a closed-loop referral system. METHODS: Chest pain patients were evaluated in the ED via a local rapid coronary CTA protocol and tracked prospectively for ED throughput, disposition, chest pain recidivism, and cost utilization as compared with an age-matched cohort evaluated for chest pain treated with usual care. RESULTS: One hundred eighty-three patients underwent the rapid coronary CTA protocol compared with an age-matched cohort of 184 patients treated with usual care. The median follow-up period for major adverse cardiovascular events in the coronary CTA group was 9.0 months (range, 1.8-14.5 months) and 11.1 months (range, 0-14.0 months) for the age-matched cohort. The median ED length of stay (LOS) was 5.8 hours (range, 2.6-12.3 hours) for the rapid coronary CTA cohort and 12.2 hours (range, 1.7-40.3 hours) for the age-matched cohort (P < .001). The median time to performance of coronary CTA was 2.5 hours (range, 0.4-8.7 hours) with a median time from coronary CTA performance to disposition of 2.9 hours (range, 0.8-8.6 hours). Total median hospital LOS was 5.9 hours (range, 2.7-124 hours) in the rapid coronary CTA cohort compared with 25.0 hours (range, 1.2-208 hours) in the age-matched cohort (P < .001). Hospital admission was more common in the age-matched cohort (98.9% vs 9.3%; P < .001). There was a significant reduction in total payer cost in coronary CTA group when compared to usual care ($182,064.55 vs $685,190.77; P < .001). CONCLUSIONS: Coronary CTA for ED risk stratification and disposition within a closed referral system resulted in the shortest ED LOS published to date while being safe and cost-effective.

Assessment of major adverse cardiovascular events and ischemic stroke with coronary computed tomography angiography based upon angiographic diagnosis in a high-volume single center.

BACKGROUND: Patient prognosis has been shown to directly correlate with the severity of coronary artery disease diagnosed by coronary computed tomography angiography (CCTA). Although the presence of coronary artery calcium has been associated with increased incidence of ischemic stroke, there are no data on the incidence of ischemic stroke based upon the severity of coronary artery disease by CCTA. Therefore, we sought to investigate the rate of major adverse cardiovascular events, including ischemic stroke, based upon the severity of coronary artery disease by CCTA over a 6-year period in a high-volume single military center. METHODS: We performed a retrospective chart review of all CCTA studies to evaluate the incidence of all-cause mortality, non-fatal myocardial infarction, ischemic stroke, and late revascularization (>90 days following CCTA) from January 2005 until July 2012. We reviewed 1518 CCTA reports, dividing patients into groups with obstructive (≥50% stenosis), non-obstructive (<50% stenosis), and no coronary artery disease (no angiographic disease). Subsequent major adverse cardiovascular events data (incidence of all-cause mortality, ischemic stroke, non-fatal myocardial infarction, and late revascularization) were obtained. RESULTS: Over a review period of 6 years with a resultant median follow-up period of 22 months (interquartile range = 13-34 months), the major adverse cardiovascular events rate was significantly higher with obstructive coronary artery disease compared to both non-obstructive coronary artery disease and no coronary artery disease (8.9% vs 0.7%, p < 0.001; 8.9% vs 1.6%, p < 0.001). The incidence of ischemic stroke alone was also significantly higher in those with obstructive coronary artery disease compared to those with no coronary artery disease (3.8% vs 0.4%, p < 0.001). CONCLUSION: Being free of disease on CCTA was associated with excellent cardiovascular prognosis. Obstructive coronary artery disease was associated with a significantly increased incidence of ischemic stroke. There was also a direct correlation between the severity of coronary artery disease on CCTA and cardiovascular prognosis over the follow-up period of 24 months.