Stress Testing Versus CT Angiography in Patients With Diabetes and Suspected Coronary Artery Disease

Background

The optimal noninvasive test (NIT) for patients with diabetes and stable symptoms of coronary artery disease (CAD) is unknown.

Outcomes of anatomical vs. functional testing for coronary artery disease

The development of coronary artery disease (CAD) is a major, final common pathway in heart disease worldwide. With a rise in stress testing and increased scrutiny on cost-effectiveness and radiation exposure in medical imaging, a focus on the relative merits of anatomic versus functional characterization of CAD has emerged. In this context, coronary computed tomography angiography (CCTA) is a noninvasive alternative to functional testing as a first-line test for CAD detection but is complimentary in its nature. Here, we discuss the design, results, and implications of the PROMISE trial, a randomized comparative effectiveness study of 10,003 patients across 193 sites in the United States and Canada comparing the prognostic and diagnostic power of CCTA and standard stress testing. Specifically, we discuss the safety (e.?g., contrast, radiation exposure) of CCTA versus functional testing in CAD, the need for improved selection for noninvasive testing, the frequency of downstream testing after anatomic or functional imaging, the use of imaging results in clinical management, and novel modalities of CAD risk determination using CCTA. PROMISE demonstrated that in a real-world, low-to-intermediate risk patient population referred to noninvasive testing for CAD, both CCTA and functional testing approaches have similar clinical, economic, and safety-based outcomes. We conclude with open questions in CAD imaging, specifically as they pertain to the utilization of CCTA.     

Diagnostic Performance of Hybrid Cardiac Imaging Methods for Assessment of Obstructive Coronary Artery Disease Compared With Stand-Alone Coronary Computed Tomography Angiography: A Meta-Analysis

Objectives

The current meta-analysis aimed to evaluate the diagnostic performance of hybrid cardiac imaging techniques compared with stand-alone coronary computed tomography angiography (CTA) for assessment of obstructive coronary artery disease (CAD).

The External Validity of Prediction Models for the Diagnosis of Obstructive Coronary Artery Disease in Patients With Stable Chest Pain: Insights From the PROMISE Trial

Objectives

This study sought to externally validate prediction models for the presence of obstructive coronary artery disease (CAD).

Influence of coronary computed tomographic angiography on patient treatment and prognosis in patients with suspected stable angina pectoris

We evaluated the influence of coronary computed tomographic angiography (CTA) as a first-line diagnostic test on patient treatment and prognosis. A total of 1,055 consecutive patients with suspected stable angina pectoris (mean age 55 ± 10 years, 56% women) and a low to intermediate pretest likelihood of coronary artery disease (CAD) were included in the present study. The patients were followed for a median of 18 months. The use of downstream diagnostic testing and medical therapy after CTA were recorded. The CTA result was normal in 49%, and nonobstructive and obstructive CAD (≥50% stenosis) was demonstrated in 31% and 15% of the patients, respectively. Coronary CTA was inconclusive in 5% of the patients. The use of antiplatelet therapy decreased with normal findings from CTA, and the use of antiplatelet and lipid-lowering agents increased in patients with CAD. Additional testing was performed in 2% of patients with normal CTA findings and in 7% and 82% of patients with nonobstructive or obstructive CAD, respectively. No patients without CAD, 0.9% of patients with nonobstructive CAD, and 1.9% of patients with obstructive CAD met the primary end point (cardiovascular death and myocardial infarction, p = 0.008). No patients without CAD, 1.5% of patients with nonobstructive CAD, and 30% patients with obstructive CAD met the secondary end point (cardiovascular death, myocardial infarction, and coronary revascularization, p <0.0001). In conclusion, in patients suspected of having angina, the findings from CTA influence patient treatment without resulting in excessive additional testing. Coronary CTA provides important prognostic information, with excellent intermediate-term outcomes in patients with normal CTA findings.     

Comparison of sensitivity, specificity, positive predictive value, and negative predictive value of stress testing versus 64-multislice coronary computed tomography angiography in predicting obstructive coronary artery disease diagnosed by coronary angiography

Sixty-four-multislice coronary computed tomographic angiography (CTA) and coronary angiography were performed in 145 patients (mean age 67 +/- 10 years), and stress testing was performed in 47 of these patients to determine the sensitivity, specificity, positive predictive value, and negative predictive value of coronary CTA and of stress testing in diagnosing obstructive coronary artery disease (CAD) in patients with suspected CAD. In 145 patients, coronary CTA had 98% sensitivity, 74% specificity, 90% positive predictive value, and 94% negative predictive value in diagnosing obstructive CAD. In 47 patients, stress testing had 69% sensitivity, 36% specificity, 78% positive predictive value, and 27% negative predictive value for diagnosing obstructive CAD, whereas coronary CTA had 100% sensitivity, 73% specificity, 92% positive predictive value, and 100% negative predictive value for diagnosing obstructive CAD. In conclusion, coronary CTA has better sensitivity, specificity, positive predictive value, and negative predictive value than stress testing in diagnosing obstructive CAD.     

High-Sensitivity Troponin I and Coronary Computed Tomography in Symptomatic Outpatients With Suspected CAD: Insights From the PROMISE Trial

ObjectivesThe goal of this study was to examine associations between concentrations of high-sensitivity troponin I (hsTnI) (measured by using a single-molecule counting method) and obstructive coronary artery disease (CAD) in 1,844 stable, symptomatic outpatients with suspected CAD randomized to undergo coronary computed tomography angiography (CTA) in the PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) trial.BackgroundElevated concentrations of hsTnI are associated with CAD in patients with myocardial infarction. The meaning of hsTnI concentrations in stable symptomatic outpatients is not well understood.MethodsClinical characteristics and CTA results (including coronary artery calcium [CAC] scores) were expressed across hsTnI quartiles. Determinants of hsTnI concentration were identified. Multivariable logistic regression identified independent predictors of obstructive CAD₅₀ (≥50% stenosis in any vessel) and CAD₇₀ (≥70% stenosis or ≥50% left main).ResultsThe median hsTnI concentration was 1.5 ng/l; nearly all (98.5%) subjects had measurable hsTnI, and 6.1% had concentrations ≥99th percentile concentration for this assay (6 ng/l). Higher CAC scores, as well as more prevalent and diffuse CAD, was seen in upper hsTnI quartiles (all p < 0.001). Independent predictors of hsTnI concentrations included age, sex, and CAC score (all p < 0.05). After adjusting for demographic and clinical characteristics, log-transformed hsTnI concentrations were associated with obstructive CAD₅₀ (odds ratio: 1.15 per interquartile range; p = 0.02) and CAD₇₀ (odds ratio: 1.25 per interquartile range; p = 0.001).ConclusionsIn stable symptomatic outpatients undergoing nonemergent coronary CTA for the diagnosis of suspected CAD, higher concentrations of hsTnI were associated with increasing presence and severity of coronary atherosclerosis. (Prospective Multicenter Imaging Study for Evaluation of Chest Pain [PROMISE]; NCT01174550)     

Prognostic Value of Coronary CTA in Stable Chest Pain: CAD-RADS,CAC, and Cardiovascular Events in PROMISE

ObjectivesThe purpose of this study was to compare Coronary Artery Disease Reporting and Data System (CAD-RADS) to traditional stenosis categories and the coronary artery calcium score (CACS) for predicting cardiovascular events in patients with stable chest pain and suspected coronary artery disease (CAD).BackgroundThe 2016 CAD-RADS has been established to standardize the reporting of CAD on coronary CT angiography (CTA).MethodsPROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) trial participants’ CTAs were assessed by a central CT core laboratory for CACS, traditional stenosis-based categories, and modified CAD-RADS grade including high-risk coronary plaque (HRP) features. Traditional stenosis categories and CAD-RADS grade were compared for the prediction of the composite endpoint of death, myocardial infarction, or hospitalization for unstable angina over a median follow-up of 25 months. Incremental prognostic value over traditional risk factors and CACS was assessed.ResultsIn 3,840 eligible patients (mean age: 60.4 ± 8.2 years; 49% men), 3.0% (115) experienced events. CAD-RADS (concordance statistic [C-statistic] 0.747) had significantly higher discriminatory value than traditional stenosis-based assessments (C-statistic 0.698 to 0.717; all p for comparison ≤0.001). With no plaque (CAD-RADS 0) as the baseline, the hazard ratio (HR) for an event increased from 2.43 (95% confidence interval [CI]: 1.16 to 5.08) for CAD-RADS 1 to 21.84 (95% CI: 8.63 to 55.26) for CAD-RADS 4b and 5. In stepwise nested models, CAD-RADS added incremental prognostic value beyond ASCVD risk score and CACS (C-statistic 0.776 vs. 0.682; p < 0.001), and added incremental value persisted in all CACS strata.ConclusionsThese data from a large representative contemporary cohort of patients undergoing coronary CTA for stable chest pain support the prognostic value of CAD-RADS as a standard reporting system for coronary CTA.     

The PROMISE Minimal Risk Score Improves Risk Classification of Symptomatic Patients With Suspected CAD

BackgroundGuidelines for evaluating patients with suspected coronary artery disease (CAD) recommend pretest probability (PTP) estimation but provide no clear recommendations regarding diagnostic testing in patients with >5% to 15% risk of obstructive CAD. The diagnostic and prognostic value of PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) minimal risk score (PMRS) calculation in this patient group is unknown.ObjectivesThis work aims to improve the evaluation of stable patients with suspected CAD by using the PMRS, which identifies patients at minimal risk of CAD and events in patients with >5% to 15% PTP of obstructive CAD.MethodsGreater than 5% to 15% PTP patients from 2 large clinical trials were used for subcohort derivation: PROMISE (N = 10,003) and Dan-NICAD (Danish study of Non-Invasive Testing in Coronary Artery Disease) (N = 3,252). First, the PMRS cutoff associated with a prevalence of obstructive CAD ≤5% was determined in the >5% to 15% PTP PROMISE core lab computed tomographic angiography patients (discovery cohort: n = 2,191). This cutoff was validated for obstructive CAD in >5% to 15% PTP Dan-NICAD patients (CAD validation cohort: n = 1,386) and for prognostic impact on death and myocardial infarction in >5% to 15% PTP PROMISE non–core lab computed tomographic angiography patients (prognosis validation cohort: n = 2,753).ResultsIn the discovery cohort, a CAD prevalence of ≤5% was found at a PMRS of ≥34%. In the CAD validation cohort, this cutoff down-classified 442 (31.9%) of >5% to 15% PTP patients into the low PTP group (CAD ≤5%); the prevalence of obstructive CAD in down-classified patients was 3.2% compared to 7.1% in non–down-classified patients. A PMRS ≥34% was nonsignificantly associated with a lower risk of myocardial infarction and death in the prognosis validation cohort (HR: 0.58 [95% CI: 0.29-1.18]; P = 0.13).ConclusionsFor evaluating patients with suspected CAD, a combined use of traditional PTP and the PMRS correctly down-classified one-third of >5% to 15% PTP patients into a group with very low prevalence of obstructive CAD and adverse events. The proposed strategy may improve risk stratification and help reduce unneeded diagnostic testing.     

High-sensitivity cardiac troponin T level is associated with angiographic complexity of coronary artery disease: a cross-sectional study

High levels of high-sensitivity cardiac troponin T (hs-cTnT) are associated with coronary artery disease (CAD). The SYNTAX score (SXscore) is an angiographic tool used to grade the complexity and extent of CAD. We investigated the relationship between hs-cTnT levels and SXscore. We conducted a cross-sectional analysis of 408 patients who underwent first diagnostic coronary angiography between December 2011 and December 2012. SXscore was recorded, and serum hs-cTnT levels were measured in all patients. The median hs-cTnT level was 0.009 μg/L. Elevated hs-cTnT levels (≥0.014 μg/L) were observed in 136 patients (33 %). Twenty-seven patients (7 %) had complex CAD as defined by intermediate or high SXscores. The levels of hs-cTnT were significantly higher in patients with high or intermediate SXscores than in those with low SXscores (0.044 ± 0.055 vs. 0.018 ± 0.058 μg/L, p = 0.03). Multivariate analysis identified hs-cTnT level, and diabetes mellitus as independent predictors for complex CAD. The adjusted odds ratio of hs-cTnT level for predicting complex CAD was 2.86 (95 % confidence interval 1.90–4.45, p < 0.0001). Predictive value of the adjusted area under the receiver operating characteristic curve for complex CAD significantly improved after inclusion of the hs-cTnT (C statistic, 0.882 vs. 0.784). Measurement of serum hs-cTnT level has an important role in the risk stratification of patients who have a plan for diagnostic coronary angiography. In patients with clinically stable angina pectoris, slightly elevated hs-cTnT levels may indicate the presence of complex CAD.     

Comparison of Different Investigation Strategies to Defer Cardiac Testing in Patients With Stable Chest Pain

ObjectivesThis study aimed to compare the current 5 investigation strategies to defer cardiac testing in patients with stable chest pain.BackgroundFor the clinical management of stable chest pain, the identification of patients unlikely to benefit from further cardiac testing is important, but the most appropriate investigation strategy is unknown.MethodsA total of 4,207 patients referred to coronary computed tomography angiography for stable chest pain were classified into low- and high-risk groups according to the 2016 National Institute of Health and Care Excellence (NICE) guideline-determined strategy; PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) minimal risk tool–based strategy; 2019 European Society of Cardiology (ESC) guideline–determined strategy; and coronary artery calcium score (CACS), either in isolation (the CACS strategy) or as part of a weighted clinical likelihood model–based strategy (the CACS-CL strategy). The associations of obstructive coronary artery disease on coronary computed tomography angiography, major adverse cardiovascular events, and subsequent clinical management with risk groups according to different strategies were evaluated and compared.ResultsThe NICE, PROMISE, ESC, CACS, and CACS-CL strategies classified a proportion (22.63%, 29.21%, 41.84%, 46.76%, and 51.41%, respectively) of patients into low-risk groups. Compared with the NICE, PROMISE, ESC, and CACS strategies, the CACS-CL strategy had a stronger association between risk groups and obstructive coronary artery disease (odd ratios: 16.00 vs 2.93, 5.53, 7.94, and 10.39, respectively), major adverse cardiovascular events (HRs: 6.83 vs 1.90, 2.94, 4.23, and 5.13, respectively) and intensive subsequent clinical management as well as better metrics of diagnostic accuracy and positive net reclassification improvement.ConclusionsAmong contemporary strategies used to identify patients with stable chest pain at low risk, the use of CACS, especially when combined with clinical risk features, showed the strongest potential to effectively defer cardiac testing.     

Incremental Diagnostic Value of Stress Computed Tomography Myocardial Perfusion With Whole-Heart Coverage CT Scanner in Intermediate- to High-Risk Symptomatic Patients Suspected of Coronary Artery Disease

Objectives

The goal of this study was to evaluate the diagnostic accuracy of stress computed tomography myocardial perfusion (CTP) for the detection of functionally significant coronary artery disease (CAD) by using invasive coronary angiography (ICA) plus invasive fractional flow reserve (FFR) as the reference standard in consecutive intermediate- to high-risk symptomatic patients.

Myocardial perfusion by CT versus hybrid imaging

Coronary computed tomography angiography (CTA) is a reliable diagnostic test for the anatomic diagnosis of obstructive coronary artery disease (CAD). Although coronary CTA shows high sensitivity and negative predictive value for detecting stenosis greater than or equal to 50% diameter, it is limited in its ability to diagnose myocardial ischemia. Advances in computed tomography (CT) technology alone and technology that hybridizes CT with single-photon emission CT and positron emission tomography allow for the combined anatomic and physiologic diagnosis of CAD. This article summarizes these combined technologies, emphasizing the merits and limitations of each technology and their clinical implications.     

Non-invasive coronary computed tomographic angiography for patients with suspected coronary artery disease: the Coronary Angiography by Computed Tomography with the Use of a Submillimeter resolution (CACTUS) trial.

BACKGROUND: Non-invasive coronary angiography by multislice spiral computed tomography (MSCT) is a promising method for the diagnosis of coronary artery disease (CAD). However, the clinical role of this method has not been established for specific patient cohorts. Therefore, the objective of the current prospective, blinded study was to investigate the diagnostic value of coronary MSCT angiography in patients with an intermediate pre-test probability for having CAD when compared with invasive angiography. METHODS AND RESULTS: A total of 243 patients with an intermediate pre-test probability for having CAD were asked to undergo coronary 16- or 64-slice CT angiography before planned invasive angiography from 12 September 2003 to 13 July 2005. The primary end point was defined as the diagnostic accuracy in the detection of significant coronary stenosis (> or =50% lumen diameter reduction) on a per-patient and an 'intention-to-diagnose'-based analysis. Secondary end points comprised per-artery and per segment-based analyses as well as the comparison of diagnostic accuracy of 16- vs. 64-slice MSCT angiography. Of 243 enrolled patients, 129 and 114 patients were studied by 16- and 64-slice CT angiography, respectively. The overall sensitivity, negative predictive value, and specificity for CAD detection by MSCT were 99% (95% CI, 94-99%), 99% (95% CI, 94-99%), and 75% (95% CI, 67-82%), respectively. On a per-segment basis, the use of 64-slice CT was associated with significantly less inconclusive segments (7.4 vs. 11.3%, P < 0.01), resulting in a trend to an improved specificity (92 vs. 88%, P = 0.09). CONCLUSION: In patients with an intermediate pre-test probability for having CAD this large, prospective trial demonstrates that non-invasive coronary CT angiography is a very sensitive method for CAD detection. Furthermore, this method allows ruling out CAD very reliably and safely. Finally, 64-slice CT appears to be superior for CAD detection when compared with 16-slice CT.     

Second-Line Myocardial Perfusion Imaging to Detect Obstructive Stenosis: Head-to-Head Comparison of CMR and PET

BackgroundGuidelines recommend verification of myocardial ischemia by selective second-line myocardial perfusion imaging (MPI) following a coronary computed tomography angiography (CTA) with suspected obstructive coronary artery disease (CAD). Head-to-head data on the diagnostic performance of different MPI modalities in this setting are sparse.ObjectivesThe authors sought to compare, head-to-head, the diagnostic performance of selective MPI by 3.0-T cardiac magnetic resonance (CMR) and ⁸²rubidium positron emission tomography (RbPET) in patients with suspected obstructive stenosis at coronary CTA using invasive coronary angiography (ICA) with fractional flow reserve (FFR) as reference.MethodsConsecutive patients (n = 1,732, mean age: 59.1 ± 9.5 years, 57.2% men) referred for coronary CTA with symptoms suggestive of obstructive CAD were included. Patients with suspected stenosis were referred for both CMR and RbPET and subsequently ICA. Obstructive CAD was defined as FFR ≤0.80 or >90% diameter stenosis by visual assessment.ResultsIn total, 445 patients had suspected stenosis on coronary CTA. Of these, 372 patients completed both CMR, RbPET and subsequent ICA with FFR. Hemodynamically obstructive CAD was identified in 164 of 372 (44.1%) patients. Sensitivities for CMR and RbPET were 59% (95% CI: 51%-67%) and 64% (95% CI: 56%-71%); P = 0.21, respectively, and specificities 84% (95% CI: 78%-89%) and 89% (95% CI: 84%-93%]); P = 0.08, respectively. Overall accuracy was higher for RbPET compared with CMR (73% vs 78%; P = 0.03).ConclusionsIn patients with suspected obstructive stenosis at coronary CTA, CMR, and RbPET show similar and moderate sensitivities but high specificities compared with ICA with FFR. This patient group represents a diagnostic challenge with frequent mismatch between advanced MPI tests and invasive measurements. (Danish Study of Non-Invasive Diagnostic Testing in Coronary Artery Disease 2 [Dan-NICAD 2]; NCT03481712)     

Comparison of diagnostic accuracy of 64-slice computed tomography coronary angiography in women versus men with angina pectoris

We compared the diagnostic accuracy of 64-slice computed tomographic (CT) coronary angiography to detect significant coronary artery disease (CAD) in women and men. The 64-slice CT coronary angiography was performed in 402 symptomatic patients, 123 women and 279 men, with CAD prevalence of 51% and 68%, respectively. Significant CAD, defined as > or =50% coronary stenosis on quantitative coronary angiography, was evaluated on a patient, vessel, and segment level. The sensitivity and negative predictive value to detect significant CAD was very good, both for women and men (100% vs 99%, p = NS; 100% vs 98%, p = NS), whereas diagnostic accuracy (88% vs 96%; p <0.01), specificity (75% vs 90%, p <0.05), and positive predictive value (81% vs 95%, p <0.001) were lower in women. The per-segment analysis demonstrated lower sensitivity in women compared with men (82% vs 93%, p <0.001). The sensitivity in women did not show a difference in proximal and midsegments, but was significantly lower in distal segments (56% vs 85%, p <0.05) and side branches (54% vs 89%, p <0.001). In conclusion, CT coronary angiography reliably rules out the presence of obstructive CAD in both men and women. Specificity and positive predictive value of CT coronary angiography were lower in women. The sensitivity to detect stenosis in small coronary branches was lower in women compared with men.     

Diagnostic yield of current referral strategies for elective coronary angiography in suspected coronary artery disease—An analysis of the ACROSS registry

Introduction and ObjectivesThe purpose of this study was to assess the diagnostic yield of current referral strategies for elective invasive coronary angiography (ICA).MethodsWe performed a cross-sectional observational study of consecutive patients without known coronary artery disease (CAD) undergoing elective ICA due to chest pain symptoms. The proportion of patients with obstructive CAD (defined as the presence of at least one ≥50% stenosis on ICA) was determined according to the use of noninvasive testing.ResultsThe study population consisted of 1892 individuals (60% male, mean age 64±11 years), of whom 1548 (82%) had a positive noninvasive test: exercise stress test (41%), stress myocardial perfusion imaging (36%), stress echocardiogram (3%) or coronary computed tomography angiography (3%). Referral without testing occurred in 18% of patients. The overall prevalence of obstructive CAD was 57%, higher among those with previous testing (58% vs. 51% without previous testing, p=0.026) and when anatomic rather than functional tests were used (81.3% vs. 57.1%, p=0.001). A positive test and conventional risk factors were all independent predictors of obstructive CAD, with adjusted odds ratios (95% confidence interval) of 1.34 (1.03–1.74) for noninvasive testing, 1.05 (1.04–1.06) for age, 3.48 (2.81–4.29) for male gender, 1.86 (1.32–2.62) for current smoking, 1.74 (1.38–2.20) for diabetes, 1.30 (1.04–1.62) for hypercholesterolemia, and 1.39 (1.08–1.80) for hypertension.ConclusionsMore than 40% of patients without known CAD undergoing elective ICA did not have obstructive lesions, even though four out of five had a positive noninvasive test. These exams were relatively weak gatekeepers; functional tests were more often used but appeared to be outperformed by the anatomic test.     

The Prognostic Value of CAC Zero Among Individuals Presenting With Chest Pain: A Meta-Analysis

BackgroundThere is little consensus on whether absence of coronary artery calcium (CAC) can identify patients with chest pain (CP) who can safely avoid additional downstream testing.ObjectivesThe purpose of this study was to conduct a systematic review and meta-analysis investigating the utility of CAC assessment for ruling out obstructive coronary artery disease (CAD) among patients with stable and acute CP, at low-to-intermediate risk of obstructive CAD undergoing coronary computed tomography angiography (CTA).MethodsThe authors searched online databases for studies published between 2005 and 2021 examining the relationship between CAC and obstructive CAD (≥50% coronary luminal narrowing) on coronary CTA among patients with stable and acute CP.ResultsIn this review, the authors included 19 papers comprising 79,903 patients with stable CP and 13 papers including 12,376 patients with acute CP undergoing simultaneous CAC and coronary CTA assessment. Overall, 45% (95% CI: 40%-50%) of patients with stable CP and 58% (95% CI: 50%-66%) of patients with acute CP had CAC = 0. The negative predictive values for CAC = 0 ruling out obstructive CAD were 97% (95% CI: 96%-98%) and 98% (95% CI: 96%-99%) among patients with stable and acute CP, respectively. Additionally, the prevalence of nonobstructive CAD among those with CAC = 0 was 13% (95% CI: 10%-16%) among those with stable CP and 9% (95% CI: 5%-13%) among those with acute CP. A CAC score of zero predicted a low incidence of major adverse cardiac events among patients with stable CP (0.5% annual event rate) and acute CP (0.8% overall event rate).ConclusionsAmong over 92,000 patients with stable or acute CP, the absence of CAC was associated with a very low prevalence of obstructive CAD, a low prevalence of nonobstructive CAD, and a low annualized risk of major adverse cardiac events. These findings support the role of CAC = 0 in a value-based health care delivery model as a “gatekeeper” for more advanced imaging among patients presenting with CP.     

Coronary computed tomography angiography in patients with stable coronary artery disease

The treatment of coronary artery disease (CAD), which is defined by stable anatomical atherosclerotic and functional alterations of epicardial vessels or microcirculation, focuses on managing intermittent angina symptoms and preventing major adverse cardiovascular events with optimal medical therapy. When patients with known CAD present with angina and no acute coronary syndrome, they have historically been evaluated with a variety of noninvasive stress tests that utilize electrocardiography, radionuclide scintigraphy, echocardiography, or magnetic resonance imaging for determining the presence and extent of inducible myocardial ischemia. Patient event-free survival, however, is largely driven by the coronary atherosclerotic disease burden, which is not directly assessed by functional testing. Direct evaluation of coronary atherosclerotic disease by coronary computed tomography angiography (coronary CTA) has emerged as the first line noninvasive imaging modality as it improves diagnostic accuracy and positively influences clinical management. Compared to functional assessment of CAD, coronary CTA-guided management results in improved patient outcomes by facilitating prevention of myocardial infarction. Other strengths of coronary CTA include detailed atherosclerotic plaque characterization and the ability to assess functional significance of specific lesions, which may further improve risk assessment and prognosis and lead to more appropriate referrals for additional testing, such as invasive coronary angiography.     

Prognostic value of coronary CT angiography

Coronary computed tomography angiography (CTA) is a highly accurate noninvasive test that is increasingly used in symptomatic patients primarily for the diagnosis of coronary artery disease (CAD). Beyond its proven accuracy, data have now clearly demonstrated the incremental prognostic information available from coronary CTA related to the presence, extent, and severity of obstructive and nonobstructive CAD across a variety of clinical settings and patient populations. Current evidence supports the use of coronary CTA not only for the diagnosis of CAD in appropriately selected symptomatic patients but also to further refine their cardiovascular risk assessment following testing.