Prevalence of obstructive coronary artery disease in an outpatient cardiac CT angiography environment

doi:10.1016/j.ijcard.2007.06.062

International Journal of Cardiology

Volume 129, Issue 1, 16 September 2008, Pages 32-36

https://doi.org/10.1016/j.ijcard.2007.06.062 Get rights and content

Abstract

Purpose

To determine the prevalence of significant obstructive disease and non-diagnostic studies using coronary computed tomographic angiography (CTA) in an outpatient environment, to establish if CTA could help avoid unnecessary diagnostic cardiac catheterizations.

Methods

We evaluated all cases consecutively performed in our outpatient CTA laboratory seen over one year with an indication that could warrant a cardiac catheterization to establish the presence or absence of coronary artery disease (CAD). Excluded were patients without established indications for cardiac catheterization and those with known CAD (i.e.— prior myocardial infarction, revascularization). Four hundred and ninety-three (493) CTA case studies were included for the analysis. Patients were classified as normal (no luminal irregularities seen), non-obstructive coronary disease (< 50% stenosis), significant obstructive coronary disease (> 50% stenosis), or a non-diagnostic study. We assumed that all patients assigned to the obstructive CAD group and the non-diagnostic study group would require a cardiac catheterization. In the remaining two groups, a cardiac catheterization would not be necessary for diagnosis or treatment.

Results

Of the 493 index cases evaluated, 157 (32%) cases were reported to be normal, 204 patients were classified as having non-obstructive disease (41%), 93 patients were defined to have obstructive CAD (19%), and 39 cases were inconclusive (8%). Thus, in 27% of the study population, a conventional coronary angiography would be indicated to clarify the diagnosis or provide definitive disease severity for subsequent revascularization.

Conclusion

Among ambulatory patients referred for CT angiography with symptoms or positive (or equivocal) cardiac stress tests, 73% of patients were found to have either normal coronary arteries or non-obstructive disease. Given the high negative predictive power of cardiac CTA (93–99%), these patients most likely would not require subsequent invasive coronary angiography. A strategy of selective cardiac catheterization may substantially decrease unnecessary diagnostic cardiac catheterizations and reduce health care expenses.

Introduction

The cost of invasive angiography with its attendant risk has encouraged the development of new diagnostic methods that allow the coronary arteries to be visualized non-invasively. Over the last 10 years, great strides have been made in the field of cardiac imaging, particularly in the ability to visualize the coronary lumen with sufficient diagnostic accuracy [1]. Being such a modality, CTA is now being increasingly used in clinical practice.

The limitations of cardiac catheterization include risks (arterial puncture, iodinated contrast) and the need for multiple staff members including a nurse, the physician, and technologists — add to these the costs incurred during the procedure and the ensuing observational period. These limitations notwithstanding, cardiac catheterization is the only method currently available for defining the details of the entire coronary vascular anatomy, and it provides the reference standard against which other tests are compared [1], [2]. A feasible non-invasive coronary imaging modality like CTA will help avoid unnecessary diagnostic cardiac catheterizations and will significantly reduce the costs and complications associated with this invasive procedure [9], [21].

Section snippets

Methods

Four hundred and ninety-three (493) consecutive patients who underwent CTA for evaluation of obstructive CAD were included in this study: 343 men and 150 women with an average age of 59 years (18 to 87 years). Referred patients generally had an intermediate pre-test probability of obstructive disease (20–80%) as we have previously described [3]. CTA was requested for indications including: chest pain, shortness of breath, abnormal or equivocal stress test, cardiomyopathy, congestive heart

Coronary computed tomographic angiography protocol

The studies were performed with an E-Speed electron beam scanner (GE-Imatron, South San Francisco, California). The procedure of coronary CTA had been previously described [3], [4], [5], [6]. Briefly, 35 slices of a non-contrast scan was performed craniocaudally (3-mm section thickness without gap) to obtain the coronary calcium scores. Then, a flow study was performed (8 mm section thickness with 4 mm intersection gap) to obtain the circulation time (the time from the contrast injection in the

Results

Baseline Clinical Characteristics of the study group: Age (58 ± 12 years), Males (n = 299 [68%]), Diabetes mellitus (n = 48 [11%]), Hypertension (n = 259 [59%]), Hyperlipidemia (n = 187 [42%]), Current smoking (n = 40 [9%]), Positive stress test (n = 102 [23%]), equivocal stress test (n = 189 [43%]), angina pectoris (n = 76 [17%]), anginal equivalent (n = 44 [10%]. The vast majority (67%) of patients referred for CTA in our cohort consisted of patients with a stress test that was abnormal, non-diagnostic,

Discussion

It has been suggested that CTA may be helpful to rule out the presence of significant CAD and to avoid invasive coronary angiography in patients with a low to intermediate clinical likelihood of significant CAD. Previous studies have reported the diagnostic accuracy of CTA as compared to cardiac catheterization. Two studies done at this institution demonstrated accuracy of over 90%, with negative predictive values of 96 and 98% for the presence of obstructive disease [9], [10].

More recently,

Risk of invasive angiography compared with CT angiography

The procedure is associated with a small but definable risk. A survey by the Society for Cardiac Angiography and Interventions indicated that the total risk of all major complications (including mortality) from coronary angiography is approximately 2% [22]. The most common risk is associated with arterial puncture and advancement of the catheter retrogradely up the aorta to the ostium of each coronary artery. The catheter can dislodge aortic plaque, which can dissect the artery or embolize,

Limitations of the study

Impaired image quality, due to dense calcifications and multiple image artifacts including coronary artery motion and breathing artifacts, limits the clinical utility of non-invasive coronary angiography [23]. In this study, 8% of all patients had non-diagnostic studies, with most due to dense calcifications.

We utilized a cutpoint of 50% luminal severity due to the inexactness of measuring stenosis on CTA. Symptomatic lesions with greater than 50%–75% diameter stenosis are generally considered

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Clinical outcomes following a strategy of optimized medical management and selective "downstream" procedures following coronary computed tomography angiography
2013, International Journal of Cardiology
Citation Excerpt :
Conceivably, more intense medication use may have contributed to the decrease in clinical events observed in our study. In addition, increase in the frequency of downstream non-invasive testing and cardiac procedures with increasing severity of atherosclerosis likely contributed to our findings [36,37]. Among the patients with moderate and severe stenosis, downstream testing and procedure use were high, but the pattern of testing differed in the two subgroups.
Prior studies have shown a consistent relationship between coronary artery calcium (CAC) scores or the degree of coronary stenoses on coronary computed tomography angiography (CCTA) and all-cause mortality. Whether CCTA-targeted therapy, including intensive medical management, stress testing and/or invasive coronary angiography (ICA), can lead to a substantial reduction in adverse outcomes is not yet known.
We retrospectively analyzed 691 patients (55 ± 13 years, male = 63%) from a single medical practice who underwent a CAC scan and CCTA and were followed for a mean of 2.9 ± 1.0 years. Of these, 416 (60%) patients were asymptomatic. All changes in medications, coronary risk factors (including lipids profiles), downstream testing, revascularization procedures, and clinical events (myocardial infarction and death) were recorded.
Among our patients cohort 279 (40%) had no coronary artery disease. The most severe stenosis was < 50% in 314 (46%) patients, 50–70% in 76 (11%) patients, and > 70% in 22 (3%) patients. A high frequency of medical therapy was employed for those patients with any degree of stenosis, while stress testing was primarily applied for patients with > 50% stenosis and ICA was primarily performed in those with > 70% stenosis. Only two non-cardiovascular deaths and no cardiovascular deaths occurred during the follow-up period.
Our findings support the hypotheses that among patients undergoing CCTA, comprehensive medical management, including targeted percutaneous coronary interventions and increasingly intensive medical therapy with progressively worse CCTA findings, can reduce event rates among patients with abnormal CCTA studies.
Positive predictive value of computed tomography coronary angiography in clinical practice
2012, International Journal of Cardiology
Citation Excerpt :
Since we investigated patients that were clinically referred for non-invasive evaluation of chest pain, our findings better reflect daily clinical practice. Other studies investigating patients undergoing CTCA for clinical indications found even lower numbers for prevalence of obstructive CAD (19–21%) [8,22]. However, in these studies no data of ICA were reported.
Several studies have investigated the diagnostic performance of computed tomography coronary angiography (CTCA) for the detection of significant coronary artery disease (CAD). These studies were performed in patients that were already referred for invasive coronary angiography (ICA) and prevalence of significant CAD was high. Although the negative predictive value of CTCA was consistently high, a wide range of positive predictive values (PPVs) was reported. Thus, the PPV of CTCA in patients that undergo CTCA as part of a clinical diagnostic evaluation remains unclear. This study investigated the PPV of CTCA for the detection of significant CAD in clinical practice.
A total of 181 patients with low to intermediate pre-test probability CAD that were referred for non-invasive evaluation of chest pain underwent 64-slice CTCA. CTCA was scored per segment as normal, non-obstructive CAD or obstructive CAD (> 50% diameter stenosis). All patients with obstructive CAD according to CTCA, underwent ICA. Significant CAD was defined as > 50% diameter stenosis on ICA.
According to CTCA, 65 (35.9%) patients had obstructive CAD. In 26 (14.4%) patients, significant CAD was found by ICA. The PPV for detection of significant CAD per patient, per vessel and per segment were 40.0% (26/65, 95% CI: 30.6–50.2%), 31.3% (36/115, 95% CI: 24.7–38.8%) and 25.5% (42/165; 95% CI: 20.3–31.4%), respectively.
The PPV of CTCA for detection of significant CAD in patients with low to intermediate probability CAD that are clinically referred for non-invasive evaluation of chest pain is markedly lower than generally reported.
Factors determining success in percutaneous revascularization of chronic total coronary occlusion: Multidetector computed tomography analysis
2012, Revista Espanola de Cardiologia
La revascularización percutánea de las oclusiones crónicas totales supone un desafío técnico, y tiene una tasa de éxito menor que las demás angioplastias. Conocer los predictores de fracaso permitiría mejorar la selección de pacientes con mayores posibilidades de éxito. Diseñamos un estudio para identificar los datos de la tomografía computarizada con multidetectores que podrían asociarse al fracaso del tratamiento percutáneo de las oclusiones crónicas totales.
Estudio prospectivo monocéntrico sobre 69 pacientes consecutivos, portadores de una oclusión crónica total, a los que se realizó una tomografía computarizada con multidetectores previa a la revascularización.
Se analizaron 77 lesiones, con una longitud ocluida media de 19,9 ± 14,3 mm y una duración de la oclusión de 47 ± 62 meses. El único factor predictor angiográfico independiente del fracaso de la revascularización fue la presencia de una fuerte curva entre la placa y el vaso proximal permeable (odds ratio = 3,8; intervalo de confianza del 95%, 1,2-12; p = 0,02). El único factor derivado de la tomografía computarizada con multidetectores asociado significativamente con fracaso fue la presencia de un arco de calcio que afectase a más del 50% de la circunferencia del segmento ocluido en la porción proximal (p = 0,04) y media (p = 0,03).
La tomografía computarizada con multidetectores identifica una variable no cuantificable por angiografía como predictora del fracaso de la revascularización de las oclusiones crónicas totales. En casos seleccionados podría ser útil para el cribado antes de la revascularización.
Percutaneous revascularization of chronic total coronary artery occlusion is a technical challenge and has a lower success rate than other angioplasty procedures. Identification of predictors of failure could lead to better selection of patients with the greatest possibility of success. In this study, we investigate the multidetector computed tomography features associated with failure of percutaneous treatment for chronic total coronary occlusion.
This is a prospective, single-center study of 69 consecutive patients with chronic total occlusion in whom multidetector computed tomography study was performed before percutaneous coronary revascularization.
Seventy-seven lesions were analyzed. The mean length of the occlusion was 19.9 (14.3) mm and the estimated duration of occlusion was 47 (62) months. The only angiographic factor independently predictive of failure was a severe curve between the plaque and the proximal patent vessel (odds ratio 3.8, 95% confidence interval, 1.2-12; P=.02). On multidetector computed tomography, the only factor predictive of failure was an arc of calcium affecting more than 50% of the vessel circumference in the proximal (P=.04) and middle (P=.03) third of the occlusion.
Multidetector computed tomography identified a variable that cannot be measured by angiography that can predict failure in percutaneous revascularization of chronic total coronary occlusions. In selected cases, this parameter could be useful for preprocedure screening.
Full English text available from: www.revespcardiol.org
Prognostic value of cardiac computed tomography angiography: A systematic review and meta-analysis
2011, Journal of the American College of Cardiology
Citation Excerpt :
The abstract or full text of the 39 remaining studies were evaluated to determine eligibility. Twenty-one studies (14,15,23,25,28,41–56) were excluded after further review for reasons outlined in Figure 1. Eighteen studies were identified for inclusion from the literature search (7,8,10–12,16–22,24,26–30).
The purpose of this study was to systematically review and perform a meta-analysis of the ability of cardiac computed tomography angiography (CCTA) to predict future cardiovascular events and death.
The diagnostic accuracy of CCTA is well reported. The prognostic value of CCTA has been described in several studies, but many were underpowered. Pooling outcomes increases the power to predict rare events.
We searched multiple databases for longitudinal studies of CCTA with at least 3 months follow-up of symptomatic patients with suspected coronary artery disease (CAD) reporting major adverse cardiovascular events (MACE), consisting of death, myocardial infarction (MI), and revascularization. Annualized event rates were pooled using a bivariate mixed-effects binomial regression model to calculate summary likelihood ratios and receiver-operating characteristic curves.
Eighteen studies evaluated 9,592 patients with a median follow-up of 20 months. The pooled annualized event rate for obstructive (any vessel with >50% luminal stenosis) versus normal CCTA was 8.8% versus 0.17% per year for MACE (p < 0.05) and 3.2% versus 0.15% for death or MI (p < 0.05). The pooled negative likelihood ratio for MACE after normal CCTA findings was 0.008 (95% confidence interval [CI]: 0.0004 to 0.17, p < 0.001), the positive likelihood ratio was 1.70 (95% CI: 1.42 to 2.02, p < 0.001), sensitivity was 0.99 (95% CI: 0.93 to 1.00, p < 0.001), and specificity was 0.41 (95% CI: 0.31 to 0.52, p < 0.001). Stratifying by no CAD, nonobstructive CAD (worst stenosis <50%), or obstructive CAD, there were incrementally increasing adverse events.
Adverse cardiovascular events among patients with normal findings on CCTA are rare. There are incrementally increasing future MACE with increasing CAD by CCTA.
Quantification of regional calcium burden in chronic total occlusion by 64-slice multi-detector computed tomography and procedural outcomes of percutaneous coronary intervention
2010, International Journal of Cardiology
Citation Excerpt :
Among these factors, recent reports have suggested that the presence of calcification is the most important predictor for procedural failures [2,3]. Recent advancements in MDCT technology have improved coronary imaging quality with a higher resolution, and, compared to fluoroscopy, MDCT shows much higher sensitivity and specificity in detecting calcified coronary plaques and has the advantage that it can quantify the calcification [4,5]. In addition, occlusion length, which also may play an important role as a predictive factor, can be better assessed with MDCT than coronary angiography.
One of the most important reasons for failure of percutaneous coronary intervention (PCI) in chronic total occlusion (CTO) is calcified plaque, which either prevents passage of guide wire or ruptures after balloon inflation. We sought to evaluate whether quantified calcium contents of CTO on multi-detector computed tomography (MDCT) correlate with immediate procedural outcomes.
Sixty-four patients with 72 CTO lesions who underwent 64-slice MDCT prior to PCI were investigated. The lesions were divided into 2 groups according to procedural outcomes (55 lesions with PCI-success group, 17 lesions with PCI-failure group). Clinical, angiographic and MDCT parameters, including regional calcium volume (RCaV), regional calcium score (RCaS), regional calcium equivalent mass (RCaEq), and relative calcium area at the most calcified cross section of CTO (%CaS/CSA), were compared between the two groups.
The duration of CTO was shorter in PCI-success group than PCI-failure group (7.16 ± 10.5 vs 15.59 ± 14.92 months, p = 0.011), and the procedural success rate was 76.3%. Regional calcium-related parameters (RCaV 52.86 ± 58.39 vs 7.26 ± 15.27 mm³, p < 0.001; RCaS 72.71 ± 78.4 vs 9.66 ± 20.2, p < 0.001; RCaEq 12.58 ± 12.97 vs 1.84 ± 3.716 mgCaHA, p < 0.001; %CaS/CSA 53.9 ± 20.3 vs 30.4 ± 17.1%, p = 0.009) in the occluded segment were higher and the occlusion length was longer (37.44 ± 27.48 vs 22.00 ± 18.04 mm, p < 0.021) in PCI-failure group compared to PCI-success group. Multivariate regression analysis showed that only %CaS/CSA was a significant determinant of PCI-failure.
Precise quantification of regional calcification and measurement of the occluded segment by high resolution MDCT can deliver important information for predicting procedural outcomes in PCI of CTO.
HDL-associated factors provide additional prognostic information for coronary artery disease as determined by multi-detector row computed tomography
2010, International Journal of Cardiology
A significant relationship has been noted between the lipid profile and atherosclerotic coronary artery disease (CAD) using invasive coronary angiography. We tested the hypothesis that the severity of CAD as determined by a non-invasive method, multi-detector row computed tomography (MDCT), is also associated with lipidemic factors.
The subjects included 195 consecutive patients who underwent coronary angiography using MDCT because of suspected CAD. The number of significantly stenosed vessels (VD) as evaluated by MDCT, platelet-activating factor acetylhydrolase (PAF-AH), free cholesterol (FC), phospholipid (PL), remnant-like lipoprotein particle-cholesterol (RLP-C), apolipoprotein (apo)-B, apo-C3, apo-E, and highly-sensitive C-reactive protein were determined. The subjects were divided into diabetes mellitus (DM) and non-DM groups. The HDL-associated PAF-AH level in the DM group was significantly lower than that in the non-DM group. The VD determined by MDCT was significantly associated with hypertension, administration of angiotensin II type 1 receptor blocker, high-density lipoprotein cholesterol (HDL-C), HDL-associated (H)-HDL, H-PL, H-FC and RLP-C. Multivariate analysis revealed that VD determined by MDCT was most closely correlated with HDL-C.
Lower levels of HDL-C may be an indicator for and provide additional information regarding the severity of CAD compared with other lipidemic factors.

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Prevalence of obstructive coronary artery disease in an outpatient cardiac CT angiography environment

Abstract

Purpose

Methods

Results

Conclusion

Introduction

Section snippets

Methods

Coronary computed tomographic angiography protocol

Results

Discussion

Risk of invasive angiography compared with CT angiography

Limitations of the study

J Am Coll Cardiol

Mayo Clin Proc

J Am Coll Cardiol

J Am Coll Cardiol

Am Heart J

J Am Coll Cardiol

J Am Coll Cardiol

J Am Coll Cardiol

Am J Cardiol

Continuous probabilistic prediction of angiographically significant coronary artery disease using electron beam tomography

Circulation

Coronary artery motion during the cardiac cycle and optimal ECG triggering for coronary artery imaging

Invest Radiol

Improved reproducibility of coronary artery calcium scoring by electron beam tomography with a new ECG trigger method

Invest Radiol