Diagnostic Accuracy and Impact of Computed Tomographic Coronary Angiography on Utilization of Invasive Coronary Angiography

ESC pre-test probability estimates for obstructive coronary artery disease: can they be used in Brazil?

Aims

Cardiovascular disease, primarily coronary artery disease (CAD), is the leading cause of mortality worldwide. Accurate diagnosis of CAD often requires pre-test probability (PTP) estimation, traditionally performed using scoring systems like the Diamond-Forrester (DF) and European Society of Cardiology (ESC) models. However, the applicability of such models in specific populations may vary. This study compares the performance of DF and PTP scores in the Brazilian context, using coronary computed tomography angiography (CCTA) as a reference standard.

Methods and results

PTP for obstructive CAD was calculated using DF and ESC scores in 409 symptomatic patients without known CAD who underwent CCTA between 2019 and 2022. Predicted PTP was compared with actual CAD prevalence. DF overestimated CAD prevalence across age and symptom categories, while ESC showed better alignment with actual prevalence.

Conclusion

Our study confirms that the ESC PTP model is more appropriate than the DF model for determining PTP in the Brazilian population.

Prevalence and Outcomes of Patients With Acute Ischemic Stroke With Concomitant ST-Segment-Elevation Myocardial Infarction (Results From National Inpatient Sample 2016-2019)

BACKGROUND

Acute myocardial infarction may concomitantly occur with acute ischemic stroke. The prevalence, complications, and outcomes of acute ST-segment-elevation myocardial infarction (STEMI) in patients hospitalized with acute ischemic stroke are not well studied.

METHODS

We examined hospitalized patients with acute ischemic stroke who were included in the National Inpatient Sample from 2016 to 2019. Acute ischemic stroke and STEMI were defined by using the International Classification of Diseases-Tenth Revision diagnostic codes. Patients with Non-STEMI were excluded. The prevalence of complications and outcomes were expressed as percentages. Multivariable logistic regression analysis was used to examine the association of STEMI with a primary outcome of mortality and secondary outcomes. A subgroup analysis of patients with STEMI who underwent percutaneous coronary intervention was also performed.

RESULTS

Of the total (n=2 080 795) patients with acute ischemic stroke, 0.3% (n=6275; mean age, 70.5 years, 50.1% females, 69.5% White) also had STEMI diagnosed during the hospitalization. Of these, 1775 (28.3%) died in the STEMI group and 76 435 (3.7%) died in the group without STEMI. The most frequent complications in the STEMI group were acute kidney injury, intracranial hemorrhage, and ventricular arrhythmias. All secondary outcomes were associated with the diagnosis of STEMI (odds ratio [OR], 3.19 [95% CI, 2.82-3.6]; P≤0.001). STEMI was associated with mortality (OR, 8.37 [95% CI, 7.25-9.66]; P≤0.001) and intracranial hemorrhage (OR, 2.23 [95% CI, 1.84-2.70]; P≤0.001). Percutaneous coronary intervention was performed in 14.3% of STEMI subgroup patients. Percutaneous coronary intervention is not associated with mortality (OR, 0.93 [95% CI, 0.6-1.43]; P=0.7), and intracranial hemorrhage (OR, 1.54 [95% CI, 0.0.93-2.56]; P=0.1).

CONCLUSIONS

Patients with acute ischemic stroke with STEMI have a higher percentage of mortality. Percutaneous coronary intervention in the subgroup of patients with acute ischemic stroke with concomitant STEMI was not associated with increased odds of mortality and intracranial hemorrhage.

The estimation of left ventricular function using prospective ECG-triggered coronary CT angiography

BACKGROUND

Coronary computed tomography angiography (CCTA) is vital for diagnosing coronary artery disease; however, prospective ECG-triggered acquisition, minimizing radiation exposure, limits left ventricular (LV) ejection fraction (EF) evaluation. We aimed to assess the feasibility and utility of LVEF100msec, a new index for estimating LV function using volumetric changes during 100 msec within systole.

METHODS

This retrospective study analyzed patients who underwent prospective ECG-triggered CCTA with systolic acquisition between January 2015 and June 2022. The LVEF100msec was calculated using the maximum and minimum LV volumes among the three phases (300, 350, and 400 msec post-QRS) and expressed as a percentage. Patients were classified into normal, mild-moderately reduced, or severely reduced LV function categories based on the reference test. The LVEF100msec was compared among groups, and the optimal cutoff value of LVEF100msec for predicting severe LV dysfunction was investigated.

RESULTS

The study included 271 patients (median age ​= ​58 years, 52% male). LVEF was normal in 188 (69.4%), mild-moderately reduced in 57 (21.0%), and severely reduced in 26 (9.6%) patients. Median LVEF100msec value was 9.0 (6.7-12.6) for normal LV function, 4.7 (3.1-8.8) for mild-moderately reduced, and 2.9 (1.5-3.8) for severely reduced LV function. LVEF100msec values significantly differed among categories (p ​< ​0.001). The optimal LVEF100msec cutoff for severe LV dysfunction was 4.3%, with an AUC of 0.924, sensitivity of 88%, and specificity of 89%.

CONCLUSION

The LVEF100msec may serve as a valuable indicator of severe LV dysfunction.

Prevalence and Outcomes of Patients With Acute Ischemic Stroke and Concomitant Non-ST-Elevation Myocardial Infarction (Results from the National Inpatient Sample 2016 to 2019)

Acute myocardial infarction (MI) may concomitantly occur with acute ischemic stroke. The incidence and outcomes of acute non-ST-elevation MI (NSTEMI) in acute ischemic stroke are not well studied. We examined hospitalized patients with acute ischemic stroke and a concomitant NSTEMI diagnosis who were included in the National Inpatient Sample 2016 to 2019. Acute ischemic stroke and NSTEMI were defined by using the International Classification of Diseases, Tenth Revision codes. Patients with ST-elevation MI were excluded. The outcomes were expressed as percentages. A multivariable logistic regression analysis was used to examine the association of concomitant acute ischemic stroke and NSTEMI with the primary outcome of mortality and the secondary outcomes. A subgroup analysis of patients with NSTEMI with acute ischemic stroke that underwent percutaneous coronary intervention (PCI) (angiography and angioplasty) was also performed. Of the total hospitalized patients with acute ischemic stroke (n = 1,726,265), 1.60% (n = 27,630) patients (mean age 73.5 years, 52.2% women, 67% White race) had NSTEMI diagnosed during the hospitalization. Of these, 14.1% (n = 3,890) died in the NSTEMI group and 3.4% (n = 57,670) died in the non-NSTEMI group. The most common outcomes in the NSTEMI group were Acute kidney injury 31.8%, Intracranial hemorrhage 6.6%, and sepsis 6.13%. NSTEMI in acute ischemic stroke was associated with mortality (odds ratio [OR] 3.60, 95% confidence interval [CI] 3.29 to 3.93, p ≤0.001), ICH (OR 1.46, 95% CI 1.30 to 1.63, p <0.001), and having any of the secondary outcomes (OR 2.73, 95% CI 2.57 to 2.90, p <0.001). PCI was performed in 9.14% of patients with acute ischemic stroke with NSTEMI. PCI was associated with having any of the secondary outcomes (OR 0.83, 95% CI 0.7 to 1.02, p = 0.8), mortality (OR 0.35, 95% CI 0.23 to 0.54, p <0.001), and ICH (OR 0.42, 95% CI 0.25 to 0.7, p = 0.01). In conclusion, NSTEMI in acute ischemic stroke is associated with increased mortality and other adverse events. PCI in the subgroup of patients with NSTEMI was not associated with increased mortality or intracranial bleeding.

Diagnostic accuracy of whole heart coronary magnetic resonance angiography: a systematic review and meta-analysis

BACKGROUND

The purpose of this meta-analysis was to comprehensively investigate the diagnostic ability of 1.5 T and 3.0 T whole heart coronary angiography (WHCA) to detect significant coronary artery disease (CAD) on X-ray coronary angiography.

METHODS

A literature search of electronic databases, including PubMed, Web of Science Core Collection, Cochrane advanced search, and EMBASE, was performed to retrieve and integrate articles showing significant CAD detectability of 1.5 and 3.0 T WHCA.

RESULTS

Data from 1899 patients from 34 studies were included in the meta-analysis. 1.5 T WHCA had a summary area under ROC of 0.88 in the patient-based analysis, 0.90 in the vessel-based analysis, and 0.92 in the segment-based analysis. These values for 3.0 T WHCA were 0.94, 0.95, 0.96, respectively. Contrast-enhanced 3.0 T WHCA had significantly higher specificity than non-contrast-enhanced 1.5 T WHCA on a patient-based analysis (0.87, 95% CI 0.80-0.92 vs. 0.74, 95% CI 0.64-0.82, P = 0.02). There were no differences in diagnostic performance on a patient-based analysis by use of vasodilators, beta-blockers or between Asian and Western countries.

CONCLUSIONS

The diagnostic performance of WHCA was deemed satisfactory, with contrast-enhanced 3.0 T WHCA exhibiting higher specificity compared to non-contrast-enhanced 1.5 T WHCA in a patient-based analysis. There were no significant differences in diagnostic performance on a patient-based analysis in terms of vasodilator or beta-blocker use, nor between Asian and Western countries. However, further large-scale multicentre studies are crucial for the widespread global adoption of WHCA.

Is it the Time to Move Towards Coronary Computed Tomography Angiography-Derived Fractional Flow Reserve Guided Percutaneous Coronary Intervention? The Pros and Cons

Coronary artery disease is the leading cause of mortality worldwide. Diagnosis is conventionally performed by direct visualization of the arteries by invasive coronary angiography (ICA), which has inherent limitations and risks. Measurement of fractional flow reserve (FFR) has been suggested for a more accurate assessment of ischemia in the coronary artery with high accuracy for determining the severity and decision on the necessity of intervention. Nevertheless, invasive coronary angiography-derived fractional flow reserve (ICA-FFR) is currently used in less than one-third of clinical practices because of the invasive nature of ICA and the need for additional equipment and experience, as well as the cost and extra time needed for the procedure. Recent technical advances have moved towards non-invasive high-quality imaging modalities, such as magnetic resonance, single-photon emission computed tomography, and coronary computed tomography (CT) scan; however, none had a definitive modality to confirm hemodynamically significant coronary artery stenosis. Coronary computed tomography angiography (CCTA) can provide accurate anatomic and hemodynamic data about the coronary lesion, especially calculating fractional flow reserve derived from CCTA (CCTA-FFR). Although growing evidence has been published regarding CCTA-FFR results being comparable to ICA-FFR, CCTA-FFR has not yet replaced the invasive conventional angiography, pending additional studies to validate the advantages and disadvantages of each diagnostic method. Furthermore, it has to be identified whether revascularization of a stenotic lesion is plausible based on CCTA-FFR and if the therapeutic plan can be determined safely and accurately without confirmation from invasive methods. Therefore, in the present review, we will outline the pros and cons of using CCTA-FFR vs. ICA-FFR regarding diagnostic accuracy and treatment decision-making.

Multimodality Imaging in the Detection of Ischemic Heart Disease in Women

Women with coronary artery disease tend to have a worse short and long-term prognosis relative to men and the incidence of atherosclerotic cardiovascular disease is increasing. Women are less likely to present with classic anginal symptoms when compared with men and more likely to be misdiagnosed. Several non-invasive imaging modalities are available for diagnosing ischemic heart disease in women and many of these modalities can also assist with prognostication and help to guide management. Selection of the optimal imaging modality to evaluate women with possible ischemic heart disease is a scenario which clinicians often encounter. Earlier modalities such as exercise treadmill testing demonstrate significant performance variation in men and women, while newer modalities such as coronary CT angiography, myocardial perfusion imaging and cardiac magnetic resonance imaging are highly specific and sensitive for the detection of ischemia and coronary artery disease with greater parity between sexes. Individual factors, availability, diagnostic performance, and female-specific considerations such as pregnancy status may influence the decision to select one modality over another. Emerging techniques such as strain rate imaging, CT-myocardial perfusion imaging and cardiac magnetic resonance imaging present additional options for diagnosing ischemia and coronary microvascular dysfunction.

Coronary CTA With AI-QCT Interpretation: Comparison With Myocardial Perfusion Imaging for Detection of Obstructive Stenosis Using Invasive Angiography as Reference Standard

BACKGROUND. Deep learning frameworks have been applied to interpretation of coronary CTA performed for coronary artery disease (CAD) evaluation. OBJECTIVE. The purpose of our study was to compare the diagnostic performance of myocardial perfusion imaging (MPI) and coronary CTA with artificial intelligence quantitative CT (AI-QCT) interpretation for detection of obstructive CAD on invasive angiography and to assess the downstream impact of including coronary CTA with AI-QCT in diagnostic algorithms. METHODS. This study entailed a retrospective post hoc analysis of the derivation cohort of the prospective 23-center Computed Tomographic Evaluation of Atherosclerotic Determinants of Myocardial Ischemia (CREDENCE) trial. The study included 301 patients (88 women and 213 men; mean age, 64.4 ± 10.2 [SD] years) recruited from May 2014 to May 2017 with stable symptoms of myocardial ischemia referred for nonemergent invasive angiography. Patients underwent coronary CTA and MPI before angiography with quantitative coronary angiography (QCA) measurements and fractional flow reserve (FFR). CTA examinations were analyzed using an FDA-cleared cloud-based software platform that performs AI-QCT for stenosis determination. Diagnostic performance was evaluated. Diagnostic algorithms were compared. RESULTS. Among 102 patients with no ischemia on MPI, AI-QCT identified obstructive (≥ 50%) stenosis in 54% of patients, including severe (≥ 70%) stenosis in 20%. Among 199 patients with ischemia on MPI, AI-QCT identified nonobstructive (1-49%) stenosis in 23%. AI-QCT had significantly higher AUC (all p < .001) than MPI for predicting ≥ 50% stenosis by QCA (0.88 vs 0.66), ≥ 70% stenosis by QCA (0.92 vs 0.81), and FFR < 0.80 (0.90 vs 0.71). An AI-QCT result of ≥ 50% stenosis and ischemia on stress MPI had sensitivity of 95% versus 74% and specificity of 63% versus 43% for detecting ≥ 50% stenosis by QCA measurement. Compared with performing MPI in all patients and those showing ischemia undergoing invasive angiography, a scenario of performing coronary CTA with AIQCT in all patients and those showing ≥ 70% stenosis undergoing invasive angiography would reduce invasive angiography utilization by 39%; a scenario of performing MPI in all patients and those showing ischemia undergoing coronary CTA with AI-QCT and those with ≥ 70% stenosis on AI-QCT undergoing invasive angiography would reduce invasive angiography utilization by 49%. CONCLUSION. Coronary CTA with AI-QCT had higher diagnostic performance than MPI for detecting obstructive CAD. CLINICAL IMPACT. A diagnostic algorithm incorporating AI-QCT could substantially reduce unnecessary downstream invasive testing and costs. TRIAL REGISTRATION. Clinicaltrials.gov NCT02173275.

Clinical experience regarding the diagnostic value of segment-by-segment coronary computed tomography angiography in comparison with that of invasive coronary angiography

Objective

To compare the degree of coronary stenosis (≥ 50% luminal narrowing) determined by coronary computed tomography angiography (CCTA) with that determined by invasive coronary angiography (ICA), using segment-by-segment analysis.

Materials and Methods

This was a retrospective study of the records of patients who underwent CCTA and ICA between January 2014 and June 2018 at a general hospital in Brazil. Receiver operating characteristic curve analysis was applied, and the areas under the curve were used in order to assess the overall accuracy of the methods.

Results

The degree of coronary stenosis was evaluated in a total of 844 arterial segments. The diagnostic performance of CCTA was good, with a sensitivity of 82.3%, a specificity of 96.4%, and a negative predictive value of 97.7% (95% CI: 96.5-98.5). In the segment-by-segment analysis, CCTA had excellent accuracy for the left main coronary artery and for other segments.

Conclusion

In clinical practice at general hospitals, CCTA appears to have diagnostic performance comparable to that of ICA.

Aspirin and Statin Therapy for Nonobstructive Coronary Artery Disease: Five-year Outcomes from the CONFIRM Registry

Purpose

In this cohort study, 5-year data from the Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter Registry (ie, CONFIRM) were examined to identify associations of baseline aspirin and statin use with mortality, major adverse cardiovascular events (MACE), and myocardial infarction (MI) in individuals without substantial (≥50%) stenosis.

Materials and Methods

In this prospective cohort study, all participants in the registry underwent coronary CT angiography and were classified as having no detectable coronary plaque or having nonobstructive coronary artery disease (CAD) (1%-49% stenosis). Participants with obstructive (≥50%) stenosis were excluded from analysis. The study commenced in June 2003 and was completed in March 2016. All unadjusted and risk-adjusted analyses utilized the Cox proportional hazard model with hospital sites modeled using shared frailty.

Results

A total of 6386 participants with no detectable plaque or with nonobstructive CAD were included (mean age, 56.0 years ± 13.3 [SD], 52% men). The mean follow-up period was 5.66 years ± 1.10. Nonobstructive CAD (n = 2815, 44% of all participants included in the study) was associated with a greater risk of all-cause mortality (10.6% [298 of 2815] vs 4.8% [170 of 3571], P < .001) compared to those without CAD (n = 3571, 56%). Baseline aspirin and statin use was documented for 1415 and 1429 participants, respectively, with nonobstructive CAD, and for 1560 and 1565 participants without detectable plaque, respectively. In individuals with nonobstructive CAD, baseline aspirin use was not associated with a reduction in MACE (10.9% [102 of 936] vs 14.7% [52 of 355], P = .06), all-cause mortality (9.6% [95 of 991] vs 10.9% [46 of 424], P = .468), or MI (4.4% [41 of 936] vs 6.2% [22 of 355], P = .18). On multivariate risk-adjusted analysis, baseline statin use was associated with a lower rate of MACE (hazard ratio, 0.59; 95% CI: 0.40, 0.87; P = .007). Neither therapy improved clinical outcomes for participants with no detectable plaque.

Conclusion

In participants with nonobstructive CAD, baseline use of statins, but not of aspirin, was associated with improved clinical outcomes. Neither therapy was associated with benefit in participants without plaque.Keywords: Aspirin, Statin, Coronary Artery Disease, CT Angiography, Nonobstructive Coronary Artery DiseaseClinical trial registration no. NCT01443637 Supplemental material is available for this article. © RSNA, 2022See also the commentary by Canan and Navar in this issue.

Normalized Subendocardial Myocardial Attenuation on Coronary Computed Tomography Angiography Predicts Postoperative Adverse Cardiovascular Events: Coronary CTA VISION Substudy

BACKGROUND

Abnormalities in computed tomography myocardial perfusion has been associated with coronary artery disease and major adverse cardiovascular events (MACE). We sought to investigate if subendocardial attenuation using coronary computed tomography angiography predicts MACE 30 days postelective noncardiac surgery.

METHODS

Using a 17-segment model, coronary computed tomography angiography images were analyzed for subendocardial and transmural attenuation and the corresponding blood pool. The segment with the lowest subendocardial attenuation and transmural attenuation were normalized to the segment with the highest subendocardial and transmural attenuation, respectively (SUB_normalized, and TRANS_normalized, respectively). We evaluated the independent and incremental value of myocardial attenuation to predict the composite of cardiovascular death or nonfatal myocardial infarction.

RESULTS

Of a total of 995 coronary CTA VISION (Coronary Computed Tomographic Angiography and Vascular Events in Noncardiac Surgery Patients Cohort Evaluation Study) patients, 735 had available images and complete data for these analyses. Among these patients, 60 had MACE. Based on Revised Cardiovascular Risk Index, 257, 302, 138, and 38 patients had scores of 0, 1, 2, and ≥3, respectively. On coronary computed tomography angiography, 75 patients had normal coronary arteries, 297 patients had nonobstructive coronary artery disease, 264 patients had obstructive disease, and 99 patients had extensive obstructive coronary artery disease. SUB_normalized was an independent and incremental predictor of events in the model that included Revised Cardiovascular Risk Index and coronary artery disease severity. Compared with patients in the highest tertile of SUB_normalized, patients in the second and first tertiles had an increased hazards ratio for events (2.23 [95% CI, 1.091-4.551] and 2.36 [95% CI, 1.16-4.81], respectively). TRANS_normalized, as a continuous variable, was also found to be a predictor of MACE (P=0.027).

CONCLUSIONS

Our study demonstrates that SUB_normalized and TRANS_normalized are independent and incremental predictors of MACE 30 days after elective noncardiac surgery. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01635309.

Recent Trends in Artificial Intelligence-Assisted Coronary Atherosclerotic Plaque Characterization

Coronary artery disease is a major cause of morbidity and mortality worldwide. Its underlying histopathology is the atherosclerotic plaque, which comprises lipid, fibrous and—when chronic—calcium components. Intravascular ultrasound (IVUS) and intravascular optical coherence tomography (IVOCT) performed during invasive coronary angiography are reference standards for characterizing the atherosclerotic plaque. Fine image spatial resolution attainable with contemporary coronary computed tomographic angiography (CCTA) has enabled noninvasive plaque assessment, including identifying features associated with vulnerable plaques known to presage acute coronary events. Manual interpretation of IVUS, IVOCT and CCTA images demands scarce physician expertise and high time cost. This has motivated recent research into and development of artificial intelligence (AI)-assisted methods for image processing, feature extraction, plaque identification and characterization. We performed parallel searches of the medical and technical literature from 1995 to 2021 focusing respectively on human plaque characterization using various imaging modalities and the use of AI-assisted computer aided diagnosis (CAD) to detect and classify atherosclerotic plaques, including their composition and the presence of high-risk features denoting vulnerable plaques. A total of 122 publications were selected for evaluation and the analysis was summarized in terms of data sources, methods—machine versus deep learning—and performance metrics. Trends in AI-assisted plaque characterization are detailed and prospective research challenges discussed. Future directions for the development of accurate and efficient CAD systems to characterize plaque noninvasively using CCTA are proposed.

Prognostic durability of coronary computed tomography angiography

AIMS

This large prospective cohort study sought to confirm the incremental prognostic value of coronary computed tomographic angiography (CCTA) measured over a prolonged follow-up duration. CCTA has diagnostic and prognostic value but data supporting its long-term prognostic value in a large prospectively recruited cohort with suspected coronary artery disease (CAD) has been limited.

METHODS AND RESULTS

Consecutive patients (without history of myocardial infarction, revascularization, cardiac transplantation, and congenital heart disease) were prospectively enrolled. CCTA was evaluated for CAD severity, total plaque score (TPS), and left ventricular ejection fraction. Patients were followed for major adverse events (MAE) and major adverse cardiac events (MACE).Over a total of 99 months, 8667 consecutive CCTA patients (mean age = 57.1 ± 11.1 years, 52.9% men) were prospectively enrolled and followed for a mean duration of 7.0 ± 2.6 years. At follow-up, there were a total of 723 MAE, 278 MACE, 547 all-cause deaths, 110 cardiac deaths, and 104 non-fatal myocardial infarction. Patients without coronary atherosclerosis at the time of CCTA had a very low annual event rate for both MAE and MACE (0.45%/year and 0.19%/year, respectively). Both MAE and MACE increased with increasing TPS and severity of CAD. In patients with non-obstructive CAD and who were statin-naive, TPS ≥5 had MACE rates >0.75%/year. Patients with high-risk CAD had an annual MAE and MACE rates of 3.52%/year and 2.58%/year, respectively. Adjusted hazard ratio of the severity of CAD based on multivariable analyses indicated that the prognostic values were incremental.

CONCLUSION

CCTA has independent and incremental prognostic value that is durable over time. The absence of coronary atherosclerosis portends an excellent prognosis. Patients with increasing non-obstructive plaque burden have worse prognosis and a TPS threshold ≥5 may identify a population that may benefit from statin therapy.

Coronary CT Angiography Guided Medical Therapy in Subclinical Atherosclerosis

The goals of primary prevention in coronary atherosclerosis are to avoid sudden cardiac death, myocardial infarction or the need for revascularization procedures. Successful prevention will rely on accurate identification, effective therapy and monitoring of those at risk. Identification and potential monitoring can be achieved using cardiac computed tomography (CT). Cardiac CT can determine coronary artery calcification (CAC), a useful surrogate of coronary atherosclerosis burden. Cardiac CT can also assess coronary CT angiography (CCTA). CCTA can identify arterial lumen narrowing and highlight mural atherosclerosis hitherto hidden from other anatomical approaches. Herein we consider the role of CCTA and CAC-scoring in subclinical atherosclerosis. We explore the use of these modalities in screening and discuss data that has used CCTA for guiding primary prevention. We examine therapeutic trials using CCTA to determine the effects of plaque-modifying therapies. Finally, we address the role of CCTA and CAC to guide therapy as defined in current primary prevention documents. CCTA has emerged as an essential tool in the detection and management of clinical coronary artery disease. To date, its role in subclinical atherosclerosis is less well defined, yet with modern CT scanners and continued pharmacotherapy development, CCTA is likely to achieve a more prominent place in the primary prevention of coronary atherosclerosis.

Effectiveness of point-of-care oral ivabradine for cardiac computed tomography

BACKGROUND

Coronary CT angiography (CCTA) is increasing seen as a first line investigation in patients with suspected coronary artery disease. Heart-rate control improves the image quality and diagnostic accuracy of CCTA. Typically, beta-blockers are administered to induce sinus bradycardia. Sinus bradycardia may also be induced by ivabradine. We hypothesized that in a real-world population ivabradine would be an effective alternative to metoprolol at heart rate lowering for CCTA.

METHODS

This was a retrospective analysis of consecutive patients who were exposed to an ivabradine-based (IB) versus a metoprolol-only (MO) protocol to achieve a target heart rate </ = 65bpm. Hemodynamic responses to both strategies were compared along with differences in cost and the time expired from medication administration to CCTA.

RESULTS

5955 consecutive patients were included in the analysis: 3211 were imaged during an era of a metoprolol only strategy (MO) and 2744 CCTA following an ivabradine based (IB) strategy. 2676 patients had heart rates >65 and received heart-rate lowering medication: 1958 patients had MO, and 718 received IB protocol. Target heart rate of </ = 65bpm was achieved in 77% of MO and 89% of IB patients (p < 0.01). The time from initial medication administration to CCTA was longer in the IB versus MO patients (77 versus 48 min, p < 0.01).

CONCLUSIONS

Introduction of a novel single dose ivabradine-based protocol to control heart rate for CCTA was more successful in achieving target heart rate than a metoprolol-only strategy. The use of ivabradine however incurred a 1.6-fold increase in the time delay from medication administration and imaging compared to a metoprolol only protocol.

Prognostic value of coronary computed tomography angiography in patients with prior percutaneous coronary intervention

OBJECTIVE

We sought to determine the prognostic value of coronary computed tomography angiography (CCTA) in patients with a history of percutaneous coronary intervention (PCI).

BACKGROUND

Although the prognostic value of CCTA has been well studied, its incremental value in patients with previous PCI has not been robustly investigated.

METHODS

Consecutive patients with previous PCI were prospectively enrolled and CCTA images were evaluated for coronary artery disease (CAD) severity. Patients were followed for major adverse cardiovascular events (MACE) which was a composite of cardiac death and non-fatal myocardial infarction. All-cause death was assessed as a secondary endpoint.

RESULTS

A total of 501 patients were analyzed with a mean follow-up time of 59.5 ± 32.0 months and 52 patients (10.4%) experienced MACE. Multivariable Cox regression analysis showed that CAD severity was a predictor of MACE with 0, 1, 2, and 3 vessel disease having annual rates of 1.3%, 2.2%, 2.2%, and 5.3%, respectively. All-cause death was similar in all categories of CAD.

CONCLUSIONS

In patients with previous PCI, CAD severity as measured with CCTA has independent and incremental prognostic value.

Computed tomography coronary angiography for patients with heart failure (CTA-HF): a randomized controlled trial (IMAGE-HF 1C)

AIMS

This randomized controlled trial sought to determine the financial impact of an initial diagnostic strategy of coronary computed tomography angiography (CCTA) in patients with heart failure (HF) of unknown aetiology. Invasive coronary angiography (ICA) is used to investigate HF patients. CCTA may be a non-invasive cost-effective alternative to ICA. This randomized controlled trial sought to determine the financial impact of an initial diagnostic strategy of coronary computed tomography angiography (CCTA) in patients with heart failure (HF) of unknown aetiology.

METHODS AND RESULTS

This multicentre, international trial enrolled patients with HF of unknown aetiology. The primary outcome was the cost of CCTA vs. ICA strategies at 12 months. Clinical outcomes were also collected. An 'intention-to-diagnose' analysis was performed and a secondary 'as-tested' analysis was based on the modality received. Two hundred and forty-six patients were randomized (age = 57.8 ± 11.0 years, ejection fraction = 30.1 ± 10.1%). The severity of coronary artery disease was similar in both groups. In the 121 CCTA patients, 93 avoided ICA. Rates of downstream ischaemia and viability testing were similar for both arms. There were no significant differences in the composite clinical outcomes or quality of life measures. The cost of CCTA trended lower than ICA [CDN -$871 (confidence interval, CI -$4116 to $3028)]. Using an 'as-tested' analysis, CCTA was associated with a decrease in healthcare costs (CDN -$2932, 95% CI -$6248 to $746).

CONCLUSION

In patients with HF of unknown aetiology, costs were not statistically different between the CCTA and ICA strategies.

CLINICAL TRIALS.GOV

NCT01283659.

Clinical performance of Rb-82 myocardial perfusion PET and Tc-99m-based SPECT in patients with extreme obesity

BACKGROUND

We evaluated the performance of stress imaging with technetium-99m-labeled tetrofosmin single-photon emission computed tomography (SPECT) and rubidium-82 positron emission tomography (PET) in patients with extreme obesity, defined as body mass index ≥40 kg/m2.

METHODS

We identified patients with extreme obesity who underwent angiography in our center and either stress SPECT or PET within the previous six months. Cohorts of patients with extreme obesity and a <5% pretest likelihood of CAD who underwent SPECT (N = 25) or PET (N = 25) were also included.

RESULTS

In total, 108 patients who underwent SPECT (N = 57) or PET (N = 51) were identified. Scan interpretation was classified as definitely normal or abnormal in 83.3% of PET and 60.5% of SPECT scans, respectively (P < .01). PET demonstrated higher diagnostic accuracy and normalcy rate. PET was found to have higher specificity for the pooled cohort. Similar findings were observed using stenosis cut-offs of ≥50% and ≥70%.

CONCLUSIONS

In patients with extreme obesity, PET enabled more definitive scan interpretation with less artifact compared to SPECT. PET provided higher diagnostic accuracy and specificity in the detection of obstructive coronary artery disease.

Discrimination between Obstructive Coronary Artery Disease and Cardiac Syndrome X in Women with Typical Angina and Positive Exercise Test; Utility of Cardiovascular Risk Calculators

Introduction: Nearly 40% of women with typical angina and a positive exercise tolerance test (ETT) have normal or near normal coronary angiography (CAG) labeled as cardiac syndrome X (CSX). Objective: We performed this study to evaluate the power of common cardiovascular risk calculators to distinguish patients with CSX from those with coronary artery disease (CAD). Methods: 559 women participated in the study. Three risk scores, including (1) newly pooled cohort equation of American College of Cardiology/American Heart Association (ACC/AHA) to predict 10 years risk of first atherosclerotic cardiovascular hard event (ASCVD), (2) Framingham risk score (FRS) for the prediction of 10 years coronary heart disease, and (3) the SCORE tool to estimate 10-year risk of cardiovascular mortality (SCORE), were applied. Results: CAD was diagnosed in 51.5% of the patients. 11.6% of the population had ASCVD < 2.5%, and only 13.8% of these patients had CAD on their CAG. By choosing FRS, 14.4% of patients had FRS < 7.5%, and only 11.3% of these patients had recorded CAD on CAG, while the rest of the patients were diagnosed as CSX. Using the SCORE model, 13.8% of patients had the least value (<0.5%) in whom the prevalence of CAD was 19.9%. The area under receiver operating characteristic curve (AUROC) to discriminate CSX from CAD was calculated for each scoring system, being 0.750 for ASCVD, 0.745 for FRS, and 0.728 for SCORE (p value for all AUROCs < 0.001). The Hosmer⁻Lemeshow chi squares (df, p value) for calibration were 8.787 (8, 0.361), 11.125 (8, 0.195), and 10.618 (8, 0.224) for ASCVD, FRS, and SCORE, respectively. Conclusions: Patients who have ASCVD < 2.5% or FRS < 7.5% may be appropriate cases for noninvasive imaging (Such as coronary CT angiography). CAG is indicated for patients with ASCVD ≥ 7.5% and FRS ≥ 15%, whereas the patients with intermediate risk need comprehensive patient⁻physician shared decision-making.

Is exercise stress echocardiography useful in patients with suspected obstructive coronary artery disease who have resting left bundle branch block?

BACKGROUND

Current guidelines support exercise stress echocardiography (ESE) for evaluation of suspected obstructive coronary artery disease (OCAD) in ambulant patients with left bundle branch block (LBBB). Data regarding the diagnostic utility of ESE in patients with LBBB are limited.

HYPOTHESIS

We hypothesized that the diagnostic performance of ESE for the assessment of suspected OCAD is reduced in the context of LBBB.

METHODS

We studied 191 consecutive patients with resting LBBB undergoing ESE for the investigation of suspected OCAD between 2008 and 2015 at our center. The studies were categorized as inconclusive, normal, or abnormal. Patients with an abnormal response were subcategorized as regional ischemic response or globally abnormal.

RESULTS

Eighty-two patients (43%) demonstrated a normal left ventricular contractile response (LVCR) to exercise; 92 (48%) developed an abnormal LVCR to exercise, including 70 patients with globally abnormal and 22 patients with regional ischemic responses. Of the patients with abnormal responses, 62 patients had anatomic imaging, only 29 of whom had significant OCAD, conferring an overall specificity of ESE for significant OCAD of 21% and accuracy of 52%. Of patients who developed a regionally abnormal response, 89% had significant OCAD.

CONCLUSIONS

For patients with LBBB who develop a globally abnormal LVCR during ESE, the specificity of ESE for reliably excluding significant OCAD is significantly reduced. ESE appears to be a suboptimal test for the evaluation of OCAD in patients with resting LBBB, as about 50% of patients will have an abnormal response, the majority due to globally abnormal contraction where OCAD cannot be reliably diagnosed. Alternative testing should be considered for the investigation of suspected OCAD in patients with resting LBBB.

Novel Scoring System for Prediction of Cardiac Syndrome X in Women with Typical Angina and a Positive Exercise Tolerance Test

A major diagnostic challenge for cardiologists is to distinguish cardiac syndrome X (CSX) from obstructive coronary artery disease in women with typical angina and a positive exercise tolerance test (ETT). We performed this study to develop a scoring system that more accurately predicts CSX in this patient population. Data on 976 women with typical angina and a positive ETT who underwent coronary angiography at our center were randomly divided into derivation and validation datasets. We developed a backward stepwise logistic regression model that predicted the presence of CSX, and a scoring system was derived from it. The derivation dataset (809 patients) was calibrated by uing a Hosmer-Lemeshow goodness-of-fit test (8 degrees of freedom; χ²=12.9; P=0.115), and the area under the curve was 0.758. The validation dataset (167 patients) was calibrated in the same way (8 degrees of freedom; χ²=9.0; P=0.339), and the area under the curve was 0.782. Independent predictors of CSX were age <55 years; negative histories of smoking, diabetes mellitus, hyperlipidemia, hypertension, or familial premature coronary artery disease; and highly positive ETTs. A total score >9.5 was the optimal cutoff point for differentiating CSX from obstructive coronary artery disease. Our proposed scoring system is a simple, objective, and accurate system for distinguishing CSX from obstructive coronary artery disease in women with typical angina and positive ETTs. It may help determine which of these patients need invasive coronary angiograms or noninvasive tests like computed tomographic coronary angiography.

Effects of hyperaemia on left ventricular longitudinal strain in patients with suspected coronary artery disease : A first-pass stress perfusion cardiovascular magnetic resonance imaging study

Aims

Myocardial perfusion imaging during hyperaemic stress is commonly used to detect coronary artery disease. The aim of this study was to investigate the relationship between left ventricular global longitudinal strain (GLS), strain rate (GLSR), myocardial early (E’) and late diastolic velocities (A’) with adenosine stress first-pass perfusion cardiovascular magnetic resonance (CMR) imaging.

Methods and results

44 patients met the inclusion criteria and underwent CMR imaging. The CMR imaging protocol included: rest/stress horizontal long-axis (HLA) cine, rest/stress first-pass adenosine perfusion and late gadolinium enhancement imaging. Rest and stress HLA cine CMR images were analysed using feature-tracking software for the assessment of myocardial deformation. The presence of perfusion defects was scored on a binomial scale. In patients with hyperaemia-induced perfusion defects, rest global longitudinal strain GLS (−16.9 ± 3.7 vs. −19.6 ± 3.4; p-value = 0.02), E’ (−86 ± 22 vs. −109 ± 38; p-value = 0.02), GLSR (69 ± 31 vs. 93 ± 38; p-value = 0.01) and stress GLS (−16.5 ± 4 vs. −21 ± 3.1; p < 0.001) were significantly reduced when compared with patients with no perfusion defects. Stress GLS was the strongest independent predictor of perfusion defects (odds ratio 1.43 95% confidence interval 1.14–1.78, p-value <0.001). A threshold of −19.8% for stress GLS demonstrated 78% sensitivity and 73% specificity for the presence of hyperaemia-induced perfusion defects.

Conclusions

At peak myocardial hyperaemic stress, GLS is reduced in the presence of a perfusion defect in patients with suspected coronary artery disease. This reduction is most likely caused by reduced endocardial blood flow at maximal hyperaemia because of transmural redistribution of blood flow in the presence of significant coronary stenosis.

Electronic supplementary material

The online version of this article (10.1007/s12471-017-1071-3) contains supplementary material, which is available to authorized users.

Sex Differences in Associations of Arterial Compliance With Coronary Artery Plaque and Calcification Burden

Background

Coronary artery disease is a leading killer of women. Arterial stiffness predicts myocardial infarction, and postmenopausal women have lower arterial compliance (AC) than men. We hypothesized that lower AC would be associated with greater burden of coronary artery plaque and calcification, and that these associations would be stronger in women than men.

Methods and Results

We evaluated 3639 consecutive adults without coronary artery disease history who had coronary computed tomography between 2006 and 2014. Coronary artery calcification was calculated using the Agatston method. Plaque extent was assessed by the number of arterial segments with visible plaque divided by the number of visualized segments ×100 (percent plaque score). Indexed AC was calculated as stroke volume index/central pulse pressure. We used step‐wise multivariable linear regression to assess associations of log indexed AC with log (percent plaque score+1) and log (coronary artery calcification+1). Sex‐specific models were performed if the interaction sex×AC was significant. Mean age was 57±11 years, 53% were men, and 71% were hypertensive. Interaction term sex×AC was significant for both models (P=0.008 for percent plaque score and 0.022 for coronary artery calcification). Lower indexed AC was associated with higher percent plaque score and coronary artery calcification in women (β±SE: −0.231±0.113, P=0.042 and −0.334±0.166, P=0.044, respectively), but not in men (β±SE: −0.062±0.104, P=0.551 and 0.114±0.173, P=0.510, respectively).

Conclusions

Lower AC is associated with greater burden of coronary artery plaque and calcification in women, but not in men. Our findings highlight low AC as a correlate of more‐advanced coronary artery disease and as a potential link to the worse cardiovascular outcomes in women.

Comparison of Anatomic and Clinical Outcomes in Patients Undergoing Alternative Initial Noninvasive Testing Strategies for the Diagnosis of Stable Coronary Artery Disease

Background

The optimal initial noninvasive diagnostic testing strategy for stable coronary artery disease (CAD) is unknown. Although American guidelines recommend an exercise stress test as the first‐line test, European guidelines suggest that stress imaging (myocardial perfusion imaging or stress echocardiography) or coronary computed tomography angiography may be preferable. Understanding the relationship between the initial strategy and downstream yield of obstructive CAD and major adverse cardiac events may provide insight as to the optimal strategy.

Methods and Results

We conducted a population‐based retrospective cohort study of adults in Ontario, Canada, using health administrative and clinical data. The relationship between the initial testing strategy and obstructive CAD on invasive angiography was examined. Patients were then followed from their angiogram onward to determine whether they developed a composite end point of major adverse cardiac events. After adjusting for covariates, patients with initial myocardial perfusion imaging (odds ratio: 0.92; 95% confidence interval, 0.85, 1.00), coronary computed tomography angiography (odds ratio: 1.51; 95% confidence interval, 0.91, 2.49), or stress echo (odds ratio: 0.95; 95% confidence interval, 0.84, 1.08) did not a have significantly different yield of obstructive CAD compared with those with an initial exercise stress test. Furthermore, there was no significant difference in downstream major adverse cardiac events after invasive angiography among the 4 initial testing strategies after adjusting for clinically relevant covariates.

Conclusions

Our study found no evidence to suggest significant differences in either yield of obstructive CAD or downstream major adverse cardiac events in patients undergoing an initial noninvasive testing strategy with stress or anatomical imaging compared with those undergoing an initial exercise stress test.

Incremental Prognostic Value of Quantified Vulnerable Plaque by Cardiac Computed Tomography: A Pilot Study

BACKGROUND

Coronary computed tomography (CT) angiography (CCTA) has the ability to detect, characterize, and quantify atherosclerotic plaques. The aim of our study was to evaluate the prognostic power of CCTA-quantified plaque subtypes.

MATERIALS AND METHODS

A total of 36 patients with adverse events and 36 Morise score-matched patients who remained event free on follow-up were identified. Using CCTA images, plaque subtype volumes in the major epicardial arteries were analyzed using predetermined attenuation ranges in Hounsfield units (HU): 1 to 30 HU (low attenuating), 31 to 70 HU (intermediate attenuating), 71 to 150 HU (high attenuating), and mean coronary lumen+2 SD to 1000 HU (calcified). Each epicardial artery was divided into proximal, mid, and distal segments, and plaque volumes were normalized for arterial segment length.

RESULTS

The baseline characteristics of the 2 cohorts were similar. Low-attenuation and intermediate-attenuation plaque volumes were greater in the proximal segments as well as in the entire length in the adverse event compared with the event-free group. High-attenuation plaque volume was increased only in the proximal segments in the adverse event group. There was no difference in the volume of calcified plaque between the 2 groups. The log rank test using a cutoff of 3.99 mm/mm for combined intermediate and low plaque volume showed more adverse events in patients with a plaque volume of ≥3.99 mm/mm.

CONCLUSIONS

Adverse events appear to be associated with greater volumes of low-attenuation and intermediate-attenuation plaques that reflect lipid and fibrous atherosclerosis. The difference between the 2 groups is most apparent in the proximal epicardial arteries.

Left Atrial Volume Assessed by Coronary Computed Tomography in Mid Ventricular Diastasis Predicts Adverse Events

PURPOSE

Previous studies have demonstrated that left atrial (LA) volume has incremental prognostic value in predicting major adverse cardiac events (MACE). However, the predictive ability of LA volume in mid diastasis has not been investigated. We determined the incremental predictive value of LA volume indexed to body surface area (LAVi) measured in mid ventricular diastasis.

MATERIALS AND METHODS

A total of 96 patients with MACE (all-cause mortality and nonfatal myocardial infarction) were matched to 96 controls without adverse events on follow-up. Coronary computed tomographic angiography images were reconstructed at the 75% phase (mid ventricular diastasis). LA volumes were measured and indexed to the body surface area. The predictive value of LAVi was assessed using Cox proportional hazard models for the MACE.

RESULTS

LAVi was significantly larger (P<0.001) in the cases with adverse clinical outcomes (63.8±2.1 mL/m) versus the controls (50.3±1.2 mL/m). In a multivariate analysis, both significant coronary artery disease (defined as >70% stenosis in at least 1 coronary artery) and LAVi emerged as significant predictors of MACE with P-values of 0.0022 and 0.0001, respectively.

CONCLUSIONS

A significantly larger LAVi was associated with MACE. LAVi was an incremental predictor to traditional clinical variables for MACE. The assessment of LAVi may be considered during coronary computed tomographic angiography and could potentially be incorporated into risk stratification and decision-making strategies.

Improved 5-year prediction of all-cause mortality by coronary CT angiography applying the CONFIRM score

AIMS

To investigate the long-term performance of the CONFIRM score for prediction of all-cause mortality in a large patient cohort undergoing coronary computed tomography angiography (CCTA).

METHODS AND RESULTS

Patients with a 5-year follow-up from the international multicentre CONFIRM registry were included. The primary endpoint was all-cause mortality. The predictive value of the CONFIRM score over clinical risk scores (Morise, Framingham, and NCEP ATP III score) was studied in the entire patient population as well as in subgroups. Improvement in risk prediction and patient reclassification were assessed using categorical net reclassification index (NRI) and integrated discrimination improvement (IDI). During a median follow-up period of 5.3 years, 982 (6.5%) of 15 219 patients died. The CONFIRM score outperformed the prognostic value of the studied three clinical risk scores (c-indices: CONFIRM score 0.696, NCEP ATP III score 0.675, Framingham score 0.610, Morise score 0.606; c-index for improvement CONFIRM score vs. NCEP ATP III score 0.650, P < 0.0001). Application of the CONFIRM score allowed reclassification of 34% of patients when compared with the NCEP ATP III score, which was the best clinical risk score. Reclassification was significant as revealed by categorical NRI (0.06 with 95% CI 0.02 and 0.10, P = 0.005) and IDI (0.013 with 95% CI 0.01 and 0.015, P < 0.001). Subgroup analysis revealed a comparable performance in a variety of patient subgroups.

CONCLUSIONS

The CONFIRM score permits a significantly improved prediction of mortality over clinical risk scores for >5 years after CCTA. These findings are consistent in a large variety of patient subgroups.

Improved diagnostic accuracy when combining computed tomography angiography and corrected coronary opacification in patients with coronary stents

Background The accuracy of coronary computed tomography angiography (CCTA) is sub-optimal in patients with coronary stents. Methods that can increase its diagnostic accuracy are desirable. Objective A proof-of-concept study was undertaken to determine if corrected coronary opacification (CCO) differences can improve the accuracy of CCTA in stented coronary arteries. Methods PCI patients who underwent both CCTA and invasive coronary angiography (ICA) within 3 months were analyzed. Coronary luminal attenuation values (normalized to the aorta) were measured proximally and distally to coronary stents. CCO differences were evaluated for ability to predict (i) stenosis on invasive angiography, (ii) abnormal resting coronary flow as measured by the corrected thrombolysis in myocardial infarction (TIMI) frame count (cTFC), and (iii) the combination of abnormal resting flow and significant stenosis on invasive angiography. Results Twenty-nine stented coronary arteries (n = 25, mean age =61.4 years, men =80.0%) were assessed. In stented coronary vessels, CCO identified stenosis (≥ 70%) with an area under the curve of 0.767 (P = 0.021). CCO predicted abnormal resting coronary flow with high accuracy (AUC =0.867, P = 0.002). Combined CCTA/CCO identified both abnormal cTFC and stenosis ≥70% on ICA (functionally significant stenosis) with diagnostic accuracy of 92.3%. In contrast, CCTA visual assessment alone had lower diagnostic accuracy of 66.7% for identifying functionally significant stenosis. Conclusion CCO differences are predictive of abnormal resting flow and consequently, in-stent restenosis. Incorporation of this technique may improve the specificity of CCTA in PCI patients.

Myocardial ischemia detection with single-phase CT perfusion in symptomatic patients using high-pitch helical image acquisition technique

Coronary CT angiography (CCTA) suffers from a reduced diagnostic accuracy in patients with heavily calcified coronary arteries or prior myocardial revascularisation due to artefacts caused by calcifications and stent material. CT myocardial perfusion imaging (CTMPI) yields high potential for the detection of myocardial ischemia and might help to overcome the above mentioned limitations. We analysed CT single-phase perfusion using high-pitch helical image acquisition technique in patients with prior myocardial revascularisation. Thirty-six patients with an indication for invasive coronary angiography (28 with coronary stents, 2 with coronary artery bypass grafts and 6 with both) were included in this prospective study at two study sites. All patients were examined on a 2nd generation dual-source CT system. Stress CT images were obtained using a prospectively ECG-triggered single-phase high-pitch helical image acquisition technique. During stress the tracer for myocardial perfusion (MP) SPECT imaging was administered. Rest CT images were acquired using prospectively ECG-triggered sequential CT. MP-SPECT imaging and invasive coronary angiography served as standard of reference. In this heavily diseased patient cohort CCTA alone showed a low overall diagnostic accuracy for detection of hemodynamically relevant coronary artery stenosis of only 31% on a per-patient base and 60% on a per-vessel base. Combining CCTA and CTMPI allowed for a significantly higher overall diagnostic accuracy of 78% on a per-patient base and 92% on a per-vessel base (p < 0.001). Mean radiation dose for stress CT scans was 0.9 mSv, mean radiation dose for rest CT scans was 5.0 mSv. In symptomatic patients with known coronary artery disease and prior myocardial revascularization combining CCTA and CTMPI showed significantly higher diagnostic accuracy in detection of hemodynamically significant coronary artery stenosis when compared to CCTA alone.

Evaluation of computed tomography in patients with atypical angina or chest pain clinically referred for invasive coronary angiography: randomised controlled trial

OBJECTIVE

 To evaluate whether invasive coronary angiography or computed tomography (CT) should be performed in patients clinically referred for coronary angiography with an intermediate probability of coronary artery disease.

DESIGN

 Prospective randomised single centre trial.

SETTING

 University hospital in Germany.

PARTICIPANTS

 340 patients with suspected coronary artery disease and a clinical indication for coronary angiography on the basis of atypical angina or chest pain.

INTERVENTIONS

 168 patients were randomised to CT and 172 to coronary angiography. After randomisation one patient declined CT and 10 patients declined coronary angiography, leaving 167 patients (88 women) and 162 patients (78 women) for analysis. Allocation could not be blinded, but blinded independent investigators assessed outcomes.

MAIN OUTCOME MEASURE

 The primary outcome measure was major procedural complications within 48 hours of the last procedure related to CT or angiography.

RESULTS

 Cardiac CT reduced the need for coronary angiography from 100% to 14% (95% confidence interval 9% to 20%, P<0.001) and was associated with a significantly greater diagnostic yield from coronary angiography: 75% (53% to 90%) v 15% (10% to 22%), P<0.001. Major procedural complications were uncommon (0.3%) and similar across groups. Minor procedural complications were less common in the CT group than in the coronary angiography group: 3.6% (1% to 8%) v 10.5% (6% to 16%), P=0.014. CT shortened the median length of stay in the angiography group from 52.9 hours (interquartile range 49.5-76.4 hours) to 30.0 hours (3.5-77.3 hours, P<0.001). Overall median exposure to radiation was similar between the CT and angiography groups: 5.0 mSv (interquartile range 4.2-8.7 mSv) v 6.4 mSv (3.4-10.7 mSv), P=0.45. After a median follow-up of 3.3 years, major adverse cardiovascular events had occurred in seven of 167 patients in the CT group (4.2%) and six of 162 (3.7%) in the coronary angiography group (adjusted hazard ratio 0.90, 95% confidence interval 0.30 to 2.69, P=0.86). 79% of patients stated that they would prefer CT for subsequent testing. The study was conducted at a University hospital in Germany and thus the performance of CT may be different in routine clinical practice. The prevalence was lower than expected, resulting in an underpowered study for the predefined primary outcome.

CONCLUSIONS

 CT increased the diagnostic yield and was a safe gatekeeper for coronary angiography with no increase in long term events. The length of stay was shortened by 22.9 hours with CT, and patients preferred non-invasive testing.Trial registration ClinicalTrials.gov NCT00844220.

The Prognostic Value of Percentage Total Plaque Score Adjusted to Age

Background:

Total plaque score (TPS) on coronary computed tomography angiography (CCTA) has been validated as a surrogate measure of coronary artery disease (CAD) burden and is prognostic. We propose a novel measure, percentage TPS adjusted to age (%TPS/age), that may reflect vascular age and potentially more rapidly progressive atherosclerosis and evaluate its potential prognostic value.

Methods:

%TPS/age was calculated for consecutive patients prospectively enrolled into our institutional CCTA registry and evaluated for primary composite outcome of cardiac death, nonfatal myocardial infarction, and late revascularization.

Results:

Of 1896 patients identified (mean age 57.7 ± 11.4 years, 50.1% male, median follow-up 18.6 months [interquartile range: 15.3, 32.4]), 552 (29%) had %TPS/age = 0 (no atherosclerosis), with 1 (0.2%) primary outcome observed (annual event rate [AER] = 0.1%). Two events (0.4%, AER = 0.3%) were observed in %TPS/age < 0.314 category, 22 (5.0%, AER = 2.2%) in %TPS/age 0.314 to 0.699 category, and 54 (12.0%, AER = 5.7%) in %TPS/age ≥ 0.700 category. After adjusting for clinical predictors and obstructive CAD, higher %TPS/age category was associated with hazard ratio 1.95 (1.31-2.88, P < .001) for primary outcome on multivariable analysis, Harrell-C-Statistic 0.87 (confidence interval 95%: 0.84-0.90), and net reclassification improvement of 0.71 ( P < .001).

Conclusion:

%TPS/Age has incremental prognostic value to traditional risk factors and CCTA measures of CAD and improves evaluation of burden of coronary atherosclerosis and clinical risk.

Recent Update on Radiation Dose Assessment for the State-of-the-Art Coronary Computed Tomography Angiography Protocols

OBJECTIVES

This study aimed to measure the absorbed doses in selected organs for prospectively ECG-triggered coronary computed tomography angiography (CCTA) using five different generations CT scanners in a female adult anthropomorphic phantom and to estimate the effective dose (HE).

MATERIALS AND METHODS

Prospectively ECG-triggered CCTA was performed using five commercially available CT scanners: 64-detector-row single source CT (SSCT), 2 × 32-detector-row-dual source CT (DSCT), 2 × 64-detector-row DSCT and 320-detector-row SSCT scanners. Absorbed doses were measured in 34 organs using pre-calibrated optically stimulated luminescence dosimeters (OSLDs) placed inside a standard female adult anthropomorphic phantom. HE was calculated from the measured organ doses and compared to the HE derived from the air kerma-length product (PKL) using the conversion coefficient of 0.014 mSv∙mGy-1∙cm-1 for the chest region.

RESULTS

Both breasts and lungs received the highest radiation dose during CCTA examination. The highest HE was received from 2 × 32-detector-row DSCT scanner (6.06 ± 0.72 mSv), followed by 64-detector-row SSCT (5.60 ± 0.68 and 5.02 ± 0.73 mSv), 2 × 64-detector-row DSCT (1.88 ± 0.25 mSv) and 320-detector-row SSCT (1.34 ± 0.48 mSv) scanners. HE calculated from the measured organ doses were about 38 to 53% higher than the HE derived from the PKL-to-HE conversion factor.

CONCLUSION

The radiation doses received from a prospectively ECG-triggered CCTA are relatively small and are depending on the scanner technology and imaging protocols. HE as low as 1.34 and 1.88 mSv can be achieved in prospectively ECG-triggered CCTA using 320-detector-row SSCT and 2 × 64-detector-row DSCT scanners.

Economic Outcomes With Anatomical Versus Functional Diagnostic Testing for Coronary Artery Disease

BACKGROUND

PROMISE (PROspective Multicenter Imaging Study for Evaluation of Chest Pain) found that initial use of at least 64-slice multidetector computed tomography angiography (CTA) versus functional diagnostic testing strategies did not improve clinical outcomes in stable symptomatic patients with suspected coronary artery disease (CAD) requiring noninvasive testing.

OBJECTIVE

To conduct an economic analysis for PROMISE (a major secondary aim of the study).

DESIGN

Prospective economic study from the U.S. perspective. Comparisons were made according to the intention-to-treat principle, and CIs were calculated using bootstrap methods. (ClinicalTrials.gov: NCT01174550).

SETTING

190 U.S. centers.

PATIENTS

9649 U.S. patients enrolled in PROMISE between July 2010 and September 2013. Median follow-up was 25 months.

MEASUREMENTS

Technical costs of the initial (outpatient) testing strategy were estimated from Premier Research Database data. Hospital-based costs were estimated using hospital bills and Medicare cost-charge ratios. Physician fees were taken from the Medicare Physician Fee Schedule. Costs were expressed in 2014 U.S. dollars, discounted at 3% annually, and estimated out to 3 years using inverse probability weighting methods.

RESULTS

The mean initial testing costs were $174 for exercise electrocardiography; $404 for CTA; $501 to $514 for pharmacologic and exercise stress echocardiography, respectively; and $946 to $1132 for exercise and pharmacologic stress nuclear testing, respectively. Mean costs at 90 days were $2494 for the CTA strategy versus $2240 for the functional strategy (mean difference, $254 [95% CI, -$634 to $906]). The difference was associated with more revascularizations and catheterizations (4.25 per 100 patients) with CTA use. After 90 days, the mean cost difference between the groups out to 3 years remained small.

LIMITATION

Cost weights for test strategies were obtained from sources outside PROMISE.

CONCLUSION

Computed tomography angiography and functional diagnostic testing strategies in patients with suspected CAD have similar costs through 3 years of follow-up.

PRIMARY FUNDING SOURCE

National Heart, Lung, and Blood Institute.

Assessment of left ventricular ejection fraction using low radiation dose computed tomography

BACKGROUND

Cardiac CT is a non-invasive modality with the ability to estimate LVEF. However, given its limited temporal resolution and radiation, there has been initial resistance to use CT to measure LVEF. Developing an accurate, fast, low radiation dose protocol is desirable.

OBJECTIVE

The objective of this study is to demonstrate that a 'low radiation dose' 64 slice cardiac computed tomography (CT) protocol is feasible and can accurately measure left ventricular ejection fraction (LVEF) while delivering a radiation dose lower than radionuclide angiography (RNA).

METHODS

Patients undergoing RNA were prospectively screened and enrolled to undergo a 'low-dose' 64 slice CT LVEF protocol. LVEF measures, duration of each study and radiation dose between CT and RNA were compared.

RESULTS

A total of 77 patients (mean age = 61.8 ± 12.2 years and 58 men) were analyzed. The mean LVEF measured by CT and RNA were 41.9 ± 15.2% and 39.4 ± 13.9%, respectively, (P = 0.154) with a good correlation (r = 0.863). Bland-Altman plot revealed a good agreement between the CT and RNA LVEF (mean difference of -2.4). There was good agreement between CT LVEF and RNA for identifying patients with LVEF ≤30% (kappa = 0.693) and LVEF ≥50% (kappa = 0.749). The mean dose estimated effective dose for CT and RNA were 4.7 ± 1.6 and 9.5 ± 1.0 mSv, respectively. The mean CT LVEF imaging duration (4:32 ± 3:05 minutes) was significantly shorter than the RNA image acquisition time (9:05 ± 2:36 minutes; p < 0.001).

CONCLUSION

The results of our study suggest that low-dose CT LVEF protocol is feasible, accurate, and fast while delivering a lower radiation dose than traditional RNA.

Association of Thoracic Aorta Calcium Score With Exercise Blood Pressure Response and Clinical Outcomes in Elderly Individuals: Differential Impact of Aorta Calcification Compared With Coronary Artery Calcification

BACKGROUND

The structure of the aorta is considered to influence exercise systolic blood pressure (SBP) response, which, in turn, might impact upon adverse outcomes. The current study sought to investigate the relationship of aortic calcification and exercise SBP with adverse outcomes among elderly individuals.

METHODS AND RESULTS

We retrospectively reviewed 702 elderly individuals (>65 years of age) without obstructive coronary artery disease (CAD; luminal stenosis <50%) who underwent coronary computed tomography (CT) and exercise treadmill testing. ΔSBPstage2 and ΔSBPpeak were defined as the difference in systolic blood pressure (SBP) between rest and stage 2 or peak exercise, respectively. Thoracic aortic calcium score (TACS) and coronary artery calcium score (CACS) were measured using CT scanning procedures. The primary endpoints were defined as all-cause death, admission for heart failure, obstructive CAD requiring coronary intervention, and stroke. In multivariable models, ΔSBPstage2 and ΔSBPpeak were positively related with log(TACS+1), even after adjusting for various clinical variables, baseline SBP, and CACS (P<0.001). During a median follow-up period of 65 months, there were 59 events (8.4%). In a multivariate Cox regression model, independent predictors for all events were age (hazard ratio [HR], 1.12; 95% CI, 1.05-1.19; P<0.001), dyslipidemia (HR, 1.96; 95% CI, 1.14-3.37; P=0.015), and the 4th quartile of TACS (HR, 1.24; 95% CI, 1.03-1.49; P=0.024). Among individual events, the 4th quartile of TACS was the only independent predictor for stroke (HR, 2.15; 95% CI, 1.09-5.13; P=0.044), whereas CACS ≥400 mm(3) was an independent predictor for obstructive CAD requiring intervention (HR, 7.04; 95% CI, 1.58-31.36; P=0.010).

CONCLUSIONS

Aortic calcification was related to SBP response during exercise and was an independent predictor for outcomes, especially stroke, regardless of resting SBP or CACS.

Prediction of atherosclerotic disease progression using LDL transport modelling: a serial computed tomographic coronary angiographic study

AIM

To investigate the efficacy of low-density lipoprotein (LDL) transport simulation in reconstructed arteries derived from computed tomography coronary angiography (CTCA) to predict coronary segments that are prone to progress.

METHODS AND RESULTS

Thirty-two patients admitted with an acute coronary event who underwent 64-slice CTCA after percutaneous coronary intervention and at 3-year follow-up were included in the analysis. The CTCA data were used to reconstruct the coronary anatomy of the untreated vessels at baseline and follow-up, and LDL transport simulation was performed in the baseline models. The computed endothelial shear stress (ESS), LDL concentration, and CTCA-derived plaque characteristics were used to identify predictors of substantial disease progression (defined as an increase in the plaque burden at follow-up higher than two standard deviations of the intra-observer variability of the expert who performed the analysis). Fifty-eight vessels were analysed. High LDL concentration [odds ratio (OR): 2.16; 95% confidence interval (CI): 1.64-2.84; P = 0.0054], plaque burden (OR: 1.40; 95% CI: 1.13-1.72; P = 0.0017), and plaque area (OR: 3.46; 95% CI: 2.20-5.44; P≤ 0.0001) were independent predictors of a substantial disease progression at follow-up. The ESS appears as a predictor of disease progression in univariate analysis but was not an independent predictor when the LDL concentration was entered into the multivariate model. The accuracy of the model that included the LDL concentration was higher than the accuracy of the model that included the ESS (65.1 vs. 62.5%).

CONCLUSIONS

LDL transport modelling appears a better predictor of atherosclerotic disease progression than the ESS, and combined with the atheroma characteristics provided by CTCA is able to detect with a moderate accuracy segments that will exhibit a significant plaque burden increase at mid-term follow-up.

Coronary Artery Disease in French Canadians-Investigation of a Suggested Vulnerable Population

BACKGROUND

There is a perception among Canadian physicians that coronary artery disease (CAD) and adverse cardiac events are more common in those of French Canadian heritage. We sought to compare the prevalence of CAD using coronary computed tomographic angiography (CCTA) in French Canadians and non-French white Canadians.

METHODS

Consecutive patients were prospectively enrolled in our institutional CCTA registry. Of 10,868 CCTA examinations, we analyzed white patients who identified themselves as French Canadian or non-French Canadian. These 2 groups were compared for baseline characteristics, cardiovascular risk factors, and routine markers for CAD on CTCA. Propensity score adjustments were also made to account for differences in demographics.

RESULTS

We identified 1683 French Canadians (mean age, 58.5 ± 10.7 years; 54.2% men) and 5077 non-French white Canadians (mean age, 59.4 ± 11.4 years; 57.3% men). French Canadians were more likely to have a smoking history (64.1% vs 56.1%), diabetes (15.6% vs 13.6%), and a family history of premature CAD (53.3% vs 44.6%) (P < 0.05 for all). There was no significant difference in measures of CAD between French Canadians and non-French white Canadians in obstructive CAD (32.5% vs 32.2%; P = 0.997), total plaque score (4.6 ± 4.3 vs 4.5 ± 4.4; P = 0.616) and Agatston score (168.1 ± 319.8 vs 183.6 ± 433.7; P = 0.371). After propensity score adjustment, there was still no significant difference between the groups.

CONCLUSIONS

Our study suggests that French Canadians in the Champlain region have a greater prevalence of cardiovascular risk factors compared with non-French Canadians; however, they do not appear to have a greater prevalence or severity of coronary atherosclerosis as assessed by CCTA.

Cardiac CT assessment of left ventricular mass in mid-diastasis and its prognostic value

AIMS

To determine the influence of cardiac motion on measurements of left ventricular (LV) mass obtained with 64-slice computed tomography (CT) and to elucidate the prognostic value of LV mass on major adverse cardiac events (MACE) and all-cause mortality. Increased LV mass has been linked with MACE. Although Cardiac CT allows measurement of LV anatomy, it is susceptible to motion artefacts often requiring image acquisition during diastasis. There is a need to understand variability in LV mass measurements across phases of the cardiac cycle, and whether mid-diastolic measurements have prognostic value.

METHODS AND RESULTS

The study comprised two equally sized cohorts of patients that had undergone retrospectively gated cardiac CT: patients who had MACE and/or all-cause death at follow-up and a matched (age, sex, and risk factors) event-free cohort. LV mass was measured at mid-diastole, end-diastole, and end-systole. Correlation and agreement between phases were determined. The incremental value of mid-diastolic hypertrophy (LVH) over the National Cholesterol Education Programme (NCEP) risk was performed for LV mass indices normalized to body surface area (LVMI_BSA) or weight (LVMI_Weight). Of 166 patients, 31.3% experienced MACE and 28.9% died of any cause (follow-up 22.9 ± 13.4 months). LV mass at all cardiac phases were strongly correlated (r > 0.94). Mean mid-diastolic LVMI_BSA was higher in the cohort with events (93.7 vs. 80.7 g/m², P= 0.008) as was LVMI_Weight (2.26 vs. 1.88 g/kg, P = 0.001). LVMI_BSA and LVMI_Weight had prognostic value incremental to NCEP with 1.85 and 2.47 hazard ratios, respectively.

CONCLUSIONS

Measurement of LV mass can be obtained by cardiac CT images obtained at mid-diastasis. LV mass measurements obtained at mid-diastasis have prognostic value.

Coronary CT Angiography in Heavily Calcified Coronary Arteries: Improvement of Coronary Lumen Visualization and Coronary Stenosis Assessment With Image Postprocessing Methods

To compare the diagnostic value of coronary CT angiography (CCTA) with use of 2 image postprocessing methods (CCTA_S) and (CCTA_OS) and original data (CCTA_O) for the assessment of heavily calcified plaques. Fifty patients (41 men, 9 women; mean age 61.9 years ± 9.1) with suspected coronary artery disease who underwent CCTA and invasive coronary angiography (ICA) examinations were included in the study. Image data were postprocessed with "sharpen" and smooth reconstruction algorithms in comparison with the original data without undergoing any image postprocessing to determine the effects on suppressing blooming artifacts due to heavy calcification in the coronary arteries. Minimal lumen diameter and degree of stenosis were measured and compared between CCTA_S, CCTA_OS, and CCTA_O with ICA as the reference method. The area under the curve (AUC) by receiver-operating characteristic curve analysis (ROC) was also compared among these 3 CCTA techniques. On a per-vessel assessment, the sensitivity, specificity, positive predictive value and negative predictive value, and 95% confidence interval (CI) were 100% (95% CI: 89%, 100%), 33% (95% CI: 22%, 45%), 41% (95% CI: 30%, 53%), 100% (95% CI: 85%, 100%) for CCTA_O, 94% (95% CI: 79%, 99%), 66% (95% CI: 54%, 77%), 57% (95% CI: 43%, 70%), and 95% (95% CI: 85%, 99%) for CCTA_S, 94% (95% CI: 79%, 99%), 44% (95% CI: 32%, 57%), 44% (95% CI: 32%, 57%), and 97% (95% CI: 79%, 99%) for CCTA_OS, respectively. The AUC by ROC curve analysis for CCTA_S showed significant improvement for detection of >50% coronary stenosis in left anterior descending coronary artery compared to that of CCTA_OS and CCTA_O methods (P < 0.05), with no significance differences for detection of coronary stenosis in the left circumflex and right coronary arteries (P > 0.05).CCTA with "sharpen" reconstruction reduces blooming artifacts from heavy calcification, thus, leading to significant improvement of specificity and positive predictive value of CCTA in patients with heavily calcified plaques. However, specificity is still moderate and additional functional imaging may be needed.

Patients With Suspected Coronary Artery Disease Referred for Examinations in the Era of Coronary Computed Tomography Angiography

Invasive coronary angiography (ICA) is the gold standard in the diagnosis of coronary artery disease (CAD), however, associated with rare but severe complications. Patients with a high pretest risk should be referred directly for ICA, whereas a noninvasive strategy is recommended in the remaining patients. In the setting of a university hospital, we investigated the pattern of diagnostic tests used in daily clinical practice. During a 1-year period, consecutive patients with new symptoms suggestive of CAD and referred for exercise stress test, coronary computed tomography angiography (CCTA), single-photon emission computed tomography (SPECT), or ICA qualified for inclusion. The patients were followed for 1 year, and additional downstream diagnostic tests and need of coronary revascularization were registered. A total of 1,069 patients were included. A noninvasive test was the first examination in 797 patients (75%; exercise stress test in 37, CCTA in 450, and SPECT in 310), whereas 272 (25%) were referred directly to ICA. The ICA group had a significant higher pretest probability for CAD, and the percentage of patients with evidence of significant CAD was 31% (84 of 272 patients), whereas 18% (144 of 797 patients) in the noninvasive group (p <0.0001). In the comparison between CCTA and SPECT, there were no significant differences in downstream testing (16% [72 of 444 patients] vs 17% [53 of 310], p = 0.55), and revascularization rate (20% [14 of 69 patients with positive findings] vs 9% [6 of 67], p = 0.09). In conclusion, a noninvasive diagnostic test was chosen as the first test in 3 of 4 patients. Of the patients referred directly for noninvasive examination, 1/5 had significant CAD, whereas 1/3 of those for invasive examination.

Utilization of cardiac computed tomography angiography and outpatient invasive coronary angiography in Ontario, Canada

BACKGROUND

Cardiac computed tomography angiography (coronary CTA) has emerged as a non-invasive method of diagnosing coronary artery disease. The extent of utilization and uptake of this technology since initiation of its funding by the government of Ontario is unknown.

OBJECTIVES

The aim of our study was to examine coronary CTA utilization and the rates of elective invasive coronary angiography and revascularization before and after funding initiation.

METHODS

We studied all coronary CTAs performed on adults in Ontario after initiation of funding. We also used an interrupted time series analysis to compare the average monthly rates of invasive angiography and revascularization before and after initiation of funding.

RESULTS

There was an initial steep increase in age-and sex-standardized rates of coronary CTA from 5.0 to 11.4/100,000 over the first two quarters after funding initiation. Afterwards, there was a gradual increase in utilization from 11.4 to 17.1/100,000 over two subsequent calendar years. There was a significant reduction in both the mean monthly outpatient invasive coronary angiography (from 20.7 to 19.9 per 100,000 (p = 0.0004)) and revascularization (from 4.9 to 4.4 per 100,000 (p < 0.0001)) rates in the three years following introduction of the coronary CTA billing code as compared to the three prior to its introduction.

CONCLUSIONS

Since the introduction of coronary CTA funding in Ontario, there has been a steady and controlled increase in its utilization. The increasing use of coronary CTA was associated with a reduction in both the rates of invasive angiography and revascularization.

Diagnostic and Therapeutic Usefulness of Coronary Computed Tomography Angiography in Out-Clinic Patients Referred for Chest Pain

Coronary computed tomography angiography (CCTA) is widely used to exclude coronary artery disease (CAD) in patients with low-to-intermediate pretest probability (PTP) of obstructive CAD. The aim of our study was to investigate the reclassification by CCTA and the implications of CCTA results on management because limited studies exist on these subjects; 1,560 patients with chest pain without a history of CAD and with low or intermediate PTP of CAD referred for CCTA from the out-patient clinic were prospectively included. PTP was defined by the Duke Clinical Score as either low (<15%), low-intermediate (15% to 50%), or high-intermediate (50% to 85%). Distribution of CCTA results among the categories of PTP of CAD and the influence of CCTA results on management were analyzed. CCTA revealed obstructive CAD in 7%, 15%, and 23% of cases, in patients with low, low-intermediate, and high-intermediate PTP, respectively; 855 of 1,031 patients (83%) with intermediate PTP of CAD showed no obstructive CAD on CCTA and were consequently reclassified. Management changes after CCTA occurred in 689 patients (44%). In 633 patients (41%), medication was altered and 135 (9%) were referred for invasive coronary angiography. Treatment with statin was initiated in 442 (28%) and stopped in 71 patients (5%). Aspirin was initiated in 192 (12%) and stopped in 139 patients (9%). In conclusion, in a routine clinical cohort, CCTA resulted in reclassification in most patients. Furthermore, our study suggests that the Duke Clinical Score overestimates the probability of obstructive CAD compared with CCTA findings. Finally, CCTA results have implications on patient management, with medication changes in 41% of patients.