Cardiac fluoroscopy for the diagnosis of coronary artery disease: a meta analytic review

Lack of Association between Breast Artery Calcification Seen on Mammography and Coronary Artery Disease on Angiography

Objectives:

Some studies have found correlations between the presence of breast artery calcium (BAC) observed on routine mammograms and risk factors for coronary artery disease (CAD). The aim of this study was to investigate whether such calcifications could predict the presence of coronary atherosclerosis.

Methods:

A total of 319 female patients between 50 and 70 years of age, 187 with significant CAD and 132 with angiographically normal coronary arteries, were randomly selected from a computerised database of our central catheterisation laboratory. The patients' mammograms were evaluated independently for the presence of BAC in a blinded fashion by an experienced breast radiologist, and additional clinical data were extracted from clinical charts.

Results:

The women in the CAD group were older (62.5 vs 60.7 years, p=0.05) and had a higher prevalence of hypertension, diabetes mellitus and dyslipidaemia. Although the prevalence of BAC was marginally higher in the CAD group (43.9% vs 37.1 %, p=0.138), this tendency was eliminated after controlling for confounders. Multiple regression analyses indicated that only age above 63 years (odds ratio [OR]=3.0, 95% confidence interval [CI]= 1.8–4.9) and hypertension (OR=2.2, 95% CI= 1.2–4.1), but not angiographic evidence of CAD (OR=1.0,95% CI=0.6–1.6), predict with BAC on mammography.

Conclusions:

Despite correlation with some risk factors For CAD, the presence of BAC does not differentiate between patients with angiographic evidence of CAD and those with angiographically normal coronary arteries.

Empirical evidence that disease prevalence may affect the performance of diagnostic tests with an implicit threshold: a cross-sectional study

OBJECTIVE

To investigate the effects that prevalence has on the diagnostic performance of junior doctors in interpreting x-rays.

DESIGN

Two-armed cross-sectional design using systematic sampling.

SETTING

Emergency department in the UK.

PARTICIPANTS

From a sample of 2593 patients (1434 men and 1159 women) taken from an unselected attending cohort between January and April 2002, 967 x-rays were analysed. The sex distribution was 558 men and 409 women, and the mean age of those receiving an x-ray was 34.6.

INTERVENTIONS

The interpretation of x-rays by junior doctors after their triage into high- and low-prevalence populations by radiographers.

MAIN OUTCOME MEASURES

Sensitivity, specificity, likelihood ratios, diagnostic odds ratios and receiver operator characteristic curve.

RESULTS

There were statistically significant differences in the performance characteristics of junior doctors when interpreting high-probability and low-probability x-rays. For the high- and low-probability populations, respectively, the sensitivities were 95.8% (95% CI 91.1% to 98.1%) and 78.3% (95% CI 65.7% to 87.2%) and the specificities were 56.0% (95% CI 41.9% to 69.2%) and 92.3% (95% CI 90.0% to 94.2%). Hierarchical logistic regression showed that the sensitivity did depend on the type of x-ray being interpreted but the diagnostic odds ratios did not vary significantly with prevalence, suggesting that doctors were changing their implicit threshold between the two populations along a common receiver operator characteristic curve.

CONCLUSIONS

This study provides evidence on how the prevalence may affect the performance of diagnostic tests with an implicit threshold and potentially includes the clinical history and examination. This has implications both for clinicians applying research findings to their practice and the design of future studies.

Scanning electron microscopic analysis of different drug eluting stents after failed implantation: from nearly undamaged to major damaged polymers

BACKGROUND

Implantation of drug eluting stents (DES) in tortuous and/or calcified vessels is much more demanding compared with implantation of bare metal stents (BMS) due to their larger diameters. It is unknown whether drug eluting stent coatings get damaged while crossing these lesions.

METHODS

In 42 patients (34 male, 68.1 +/- 10 years) with 45 calcified lesions (15.9 mm +/- 7.9 mm), DES could not be implanted, even after predilatation. Diabetes was present in 19 patients (45%). Sixty-one stents were used; 19 Cypher select, 18 Taxus Liberté, 10 CoStar, 5 Endeavor RX, 4 Xience V. 3 Janus Carbostent, 1 Yukon Choice S, and 1 Axxion DES. The entire accessible surface area of these stents, in either the unexpanded and expanded state, were examined with an environmental scanning electron microscope (XL30 ESEM, Philips) to evaluate polymer or surface damage.

RESULTS

The polymers of Taxus Liberte, Cypher Select, Xience V, CoStar, and Janus DES were only slightly damaged (less than 3% of surface area), whereas the Endeavor RX Stents showed up to 20% damaged surface area. In DES without a polymer (Yukon and Axxion), it could be shown that most of the stent surface (up to 40%) were without any layer of drug.

CONCLUSION

Placement of drug eluting stents in tortuous vessels and/or calcified lesions could cause major surface damage by scratching and scraping of the polymer or drug by the arterial wall, even before implantation. There were remarkable differences among the stents examined, only minor damage with the Cypher, Taxus Costar, Janus, and Xience V, whereas the Endeavor, the Yukon, and the Janus DES showed large areas of surface injury.

Diagnostic test accuracy may vary with prevalence: implications for evidence-based diagnosis

BACKGROUND

Several studies and systematic reviews have reported results that indicate that sensitivity and specificity may vary with prevalence.

STUDY DESIGN AND SETTING

We identify and explore mechanisms that may be responsible for sensitivity and specificity varying with prevalence and illustrate them with examples from the literature.

RESULTS

Clinical and artefactual variability may be responsible for changes in prevalence and accompanying changes in sensitivity and specificity. Clinical variability refers to differences in the clinical situation that may cause sensitivity and specificity to vary with prevalence. For example, a patient population with a higher disease prevalence may include more severely diseased patients, therefore, the test performs better in this population. Artefactual variability refers to effects on prevalence and accuracy associated with study design, for example, the verification of index test results by a reference standard. Changes in prevalence influence the extent of overestimation due to imperfect reference standard classification.

CONCLUSIONS

Sensitivity and specificity may vary in different clinical populations, and prevalence is a marker for such differences. Clinicians are advised to base their decisions on studies that most closely match their own clinical situation, using prevalence to guide the detection of differences in study population or study design.

Optimizing the Selection of Surgical Candidates for Lung Volume Reduction Surgery

The optimal selection of patients for lung volume reduction surgery (LVRS) is currently based on empiric clinical findings. Patients who benefit from LVRS have the common characteristics of impaired quality of life associated with apical predominant pulmonary hyperinflation and airflow obstruction. Within this category, patients who do not benefit from LVRS appear to have small airways disease that can be detected by inspiratory resistance studies. In addition to appropriate emphysema physiology, the selection of patients for LVRS must consider medical comorbidities and perioperative risk factors. Based on findings of the National Emphysema Treatment Trial, most of the perioperative morbidity and mortality of LVRS is associated with cardiopulmonary risk that needs to be considered preoperatively. Finally, a preoperative conditioning program can provide an additional screening process to identify patients physically and emotionally prepared for surgery.

Left ventricular size determined by electron beam computed tomography predicts significant coronary artery disease and events

A novel method in the measurement of left ventricular (LV) area using noncontrast electron beam computed tomography (EBCT) was introduced and studied as a diagnostic and prognostic marker for coronary artery disease. Larger LV area measured by noncontrast EBCT was significantly associated with angiographic coronary disease and was a better predictor of coronary disease events than log calcium score.

The dilemma of diagnosing coronary calcification: angiography versus intravascular ultrasound

OBJECTIVES

We sought to determine whether careful examination of angiograms in conjunction with other clinical information could reliably detect, quantitate and localize target lesion calcification before a coronary intervention.

BACKGROUND

The presence, extent and location of calcium in coronary artery lesions are important determinants of outcome after coronary intervention. Intravascular ultrasound is proposed as a superior technique for identifying patients with coronary artery calcification. However, the precise role of this costly and invasive method has not yet been established.

METHODS

Target lesion calcification was assessed in 183 patients (155 men; mean [+/-SD] age 58 +/- 10 years) by angiography and intravascular ultrasound before a planned percutaneous coronary intervention.

RESULTS

Ultrasound detected calcium in 138 patients (>90 degrees in 56, 91 degrees to 180 degrees in 52, 181 degrees to 270 degrees in 22 and > 270 degrees in 8), whereas angiography showed calcification in 63 (1+ in 32, 2+ in 27 and 3+ in 4). The two techniques agreed in 92 patients and disagreed in 91. Sensitivity and specificity of angiography were 40% and 82%, respectively. The arc of calcium by ultrasound was greater in patients with angiographically visible calcification (175 degrees +/- 85 degrees vs. 108 degrees +/- 71 degrees, p=0.0001). The depth of calcification by ultrasound was superficial in 61 patients (44%), deep in 68 (49%) and mixed in 8 (7%). The sensitivity of angiography in identifying superficial calcium was 35%. Of 120 patients without angiographically visible calcium at the target lesion site, 83 showed calcium by ultrasound. The only predictor of ultrasound calcium in these 120 patients was angiographic calcification elsewhere in the coronary tree (p=0.0001). The probability of any calcium and superficial >90 degrees calcium were 60% and 12%, respectively, in the 90 patients without angiographic calcifications anywhere in the coronary tree.

CONCLUSIONS

Despite poor sensitivity, angiography may help identify patients requiring intravascular ultrasound. When it is angiographically visible, the arc of calcium is likely to be large and superficial. Angiographic calcification at a remote site is a predictor of angiographically undetected target lesion calcium. Patients without angiographic calcification in the coronary tree may not need routine ultrasound examination, as the likelihood of >90 degrees superficial calcium is low.

Ultrafast computed tomography as a diagnostic modality in the detection of coronary artery disease: a multicenter study

BACKGROUND

Ultrafast computed tomography (CT), by acquiring images of the proximal coronary arteries, detects coronary calcifications and has been demonstrated to be highly sensitive for the detection of coronary artery disease in many small studies. The aim of this study was to determine the relationship between ultrafast CT scanning and coronary angiography in a large number of symptomatic patients.

METHODS AND RESULTS

The study population consisted of 710 patients from six participating centers. A multivariate logistic regression model was used to evaluate the individual contributions of age, number of calcified vessels, and the calcium score for the probability of angiographically significant disease. Of the 710 patients enrolled, 427 patients had significant angiographic disease, and coronary calcification was detected in 404, yielding a sensitivity of 95%. Of the 23 patients without calcifications, 19 (83%) had single-vessel disease at angiography. Of the 283 patients without angiographically significant disease, 124 had negative ultrafast CT coronary studies, for a specificity of 44%. An increasing number of vessels with calcification present on ultrafast CT was found to increase specificity for the presence of obstructive coronary artery disease in at least one vessel (P < .0001). As the log of the calcium score increases, the probability of multivessel obstructive disease increases (P < .0001).

CONCLUSIONS

Ultrafast CT scanning is an noninvasive, non-exercise-dependent test with an excellent sensitivity for the detection of coronary artery disease. The presence of calcifications in multiple vessels and in younger populations correlates with higher specificities for obstructive disease, making ultrafast CT coronary scanning a very useful diagnostic test.

Coronary artery screening by electron beam computed tomography. Facts, controversy, and future

Coronary calcium as detected by electron beam computed tomography always signifies at least some atherosclerosis, appears to be correlated with coronary risk factors, cardiac history, and overall angiographic severity of disease, but is inconsistently related to degree of atherosclerotic lesion stenosis in a given artery. Increasing evidence, however, suggests an association between coronary artery calcium, atherosclerosis, and coronary risk. But atherosclerosis is a very common condition, its prevalence increasing with age. No fully validated method for determining the quantity of coronary calcium is available, and we do not know whether the amount of calcium is a consistently accurate reflection of the amount of atherosclerosis or whether the amount of atherosclerosis reflects the degree of risk. Furthermore, the prognostic significance of coronary calcium in any given atherosclerotic lesion is not yet established. What is clear from cohort studies, however, is that at least three quarters of asymptomatic individuals, at least half of whom would have "positive" coronary calcium electron beam computed tomographic scans, will live for at least 10 years without cardiac problems of any kind. Investigation is needed to determine whether medical intervention may impact the clinical outcome of the rest of those identified with a positive scan but destined to suffer future clinical events. Despite lack of validation, this test has widespread appeal, both to the public as a means of being able to find out the condition of their coronary arteries "without injections or dye" and to hospitals and private medical groups who view this both as an innovation in cardiovascular diagnosis and as a potentially profitable diagnostic procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Patterns of calcification in coronary artery disease. A statistical analysis of intravascular ultrasound and coronary angiography in 1155 lesions

BACKGROUND

Target lesion calcium is a marker for significant coronary artery disease and a determinant of the success of transcatheter therapy.

METHODS AND RESULTS

Eleven hundred fifty-five native vessel target lesions in 1117 patients were studied by intravascular ultrasound (IVUS) and coronary angiography. The presence, magnitude, location, and distribution of IVUS calcium were analyzed and compared with the detection and classification (none/mild, moderate, and severe) by angiography. Angiography detected calcium in 440 of 1155 lesions (38%): 306 (26%) moderate calcium and 134 (12%) severe. IVUS detected lesion calcium in 841 of 1155 (73%, P < .0001 versus angiography). The mean arc of lesion calcium measured 115 +/- 110 degrees; the mean length measured 3.5 +/- 3.7 mm. Target lesion calcium was only superficial in 48%, only deep in 28%, and both superficial and deep in 24%. The mean arc of superficial calcium measured 85 +/- 108 degrees; the mean length measured 2.4 +/- 3.4 mm. Three hundred seventy-three of 1155 reference segments (32%) contained calcium (P < .0001 compared with lesion site). The mean arc of reference calcium measured 42 +/- 80 degrees; the mean length measured 1.7 +/- 3.6 mm. Only 44 (4%) had reference calcium in the absence of lesion calcium. Angiographic detection and classification of calcium depended on arcs, lengths, location, and distribution of lesion and reference segment calcium. By discriminant analysis, the classification function for predicting angiographic calcium included the arc of target lesion calcium, the arc of superficial calcium, the length of reference segment calcium, and the location of calcium within the lesion. This model correctly predicted the angiographic detection of calcification in 74.4% of lesions and the angiographic classification (none/moderate/severe) of calcium in 62.8% of lesions.

CONCLUSIONS

IVUS detected calcium in > 70% of lesions, significantly more often than standard angiography. Although angiography is moderately sensitive for the detection of extensive lesion calcium (sensitivity, 60% and 85% for three- and four-quadrant calcium, respectively), it is less sensitive for the presence of milder degrees.

Usefulness of cinefluoroscopic detection of coronary artery calcification in the diagnostic work-up of coronary artery disease

AIM

To determine in which patients (cine)fluoroscopic detection of coronary artery calcifications is recommended for the diagnosis of coronary artery disease and the consequence of this finding for referral for cinecoronary arteriography.

MATERIALS AND METHODS

Data were retrospectively obtained from 778 patients who had been referred for cinecoronary arteriography. Excluded were patients with a previous myocardial infarction, a previous abnormal cinecoronary arteriogram and patients with unstable angina. The discriminating value was assessed with the help of the crude likelihood ratio (LR), as well as the LRs stratified for gender, age and symptomatology. The gold standard was the coronary arteriogram. Furthermore, the post-test probability was estimated using logistic regression to take dependence on age, sex and symptomatology into account.

RESULTS

The crude LR of a positive and negative test result, with 95% confidence intervals, was, respectively 5.8 (4.1-8.2) and 0.52 (0.47-0.58), but was dependent on the clinical variables. Estimated probabilities of having coronary artery disease (CAD) varied substantially for a negative as well as a positive test result with the categories of clinical variables.

CONCLUSION

(Cine)fluoroscopy discriminates between patients with and without disease; the test proved to be especially useful in females with atypical angina and patients of both sexes with non-specific chest pain.

Comparison of the diagnostic value of cinefluoroscopy and simple fluoroscopy in the detection of calcification in coronary arteries

AIM

Comparison of the diagnostic value of cinefluoroscopy and simple fluoroscopy in the detection of calcification in coronary arteries.

PATIENTS AND METHODS

Data were prospectively obtained from 143 patients in whom simple fluoroscopy as well as cinecoronary arteriography were performed. Excluded were patients with a previous myocardial infarction, a previous abnormal cinecoronary arteriogram and patients with unstable angina. With the coronary arteriogram as the gold standard, the likelihood ratios (LR) of simple fluoroscopy were determined, mismatches with cinefluoroscopy were analysed and Kappa, as a measure for inter-test agreement, was calculated.

RESULTS

The LRs with 95% confidence intervals for a positive and negative result were 5.3 (2.6-11.0) and 0.43 (0.28-0.69), respectively. There was a mismatch in 12 (8.3%) patients. Kappa with a 95% confidence interval was 0.90 (0.73-1.0).

CONCLUSIONS

Both test modalities are almost identical and conclusions with respect of the diagnostic value of cinefluoroscopy also holds for simple fluoroscopy.

Meta-analytic methods for diagnostic test accuracy

Meta-analyses of diagnostic test accuracy are uncommon and often based on separate pooling of sensitivity and specificity, which can lead to biased estimates. Recently, several appropriate methods have been developed for meta-analysing diagnostic test data from primary studies. Primary studies usually only provide binary test data, for which Moses et al. have developed a method to estimate Summary Receiver Operating Characteristic Curves, thereby taking account of possible test threshold differences between studies. Several methods are also available for analysing multicategory and continuous test data. The usefulness of applying these methods is constrained by publication bias and the generally poor quality of primary studies of diagnostic test accuracy. Meta-analysts need to highlight important defects in quality and how they affect summary estimates to ensure that better primary studies are available for meta-analysis in the future.

Prevalence of fluoroscopic coronary calcific deposits in high-risk asymptomatic persons

Coronary calcific deposits are always associated with coronary atherosclerosis. Sensitive radiographic technology can detect coronary calcium before atherosclerosis becomes symptomatic. A total of 1461 asymptomatic high-risk adult subjects were studied with digital subtraction fluoroscopy to detect coronary calcium. Risk factor data were recorded including age, sex, family history, smoking history, diabetes history, body mass index, systolic blood pressure, left ventricular hypertrophy on ECG, total serum cholesterol level, high-density lipoprotein (HDL) cholesterol, and total cholesterol/HDL ratio. Digital subtraction fluoroscopy in the left anterior oblique projection was performed in all subjects. The prevalence of calcific deposits in at least one major coronary artery was high (58.3%). Eleven percent had coronary calcium in all three major arteries. Multivariate logistic regression analysis showed significant correlations (p < 0.05) between the prevalence of coronary calcium and age, smoking history (relative risk = 1.30), diabetes history (relative risk = 1.24), and family history (relative risk = 1.26). In older subjects (at least 65 years of age), smoking and serum lipoproteins assumed greater importance as contributors to coronary calcium, whereas in younger subjects a history of diabetes was more significant. Coronary calcific deposits are prevalent in high-risk asymptomatic subjects. Their occurrence is closely related to most known risk factors.

Target lesion calcification in coronary artery disease: an intravascular ultrasound study

OBJECTIVES

The purpose of this study was to evaluate the frequency, amount and distribution of target lesion calcification in patients undergoing transcatheter therapy for symptomatic coronary artery disease.

BACKGROUND

Coronary artery target lesion calcification may be an important determinant of response to transcatheter therapy: balloon angioplasty causes dissections in calcified lesions, directional atherectomy cuts calcium poorly, rotational atherectomy causes preferential ablation of calcium and laser irradiation effect may vary. Intravascular ultrasound imaging is a highly sensitive technique for detection of plaque calcification in vivo.

METHODS

We performed intravascular ultrasound imaging before or after, or both, various transcatheter therapies in 110 patients. These 84 men and 26 women had a mean age of 60 years and a duration of angina of 22 +/- 34 months. Forty-nine patients had one-vessel, 29 had two-vessel, 25 had three-vessel and 7 had left main coronary disease. Vessels treated and imaged were the left main (n = 7), left anterior descending (n = 47), left circumflex (n = 18) and right (n = 38) coronary arteries.

RESULTS

Eighty-four patients (76%) had target lesion calcification; 29 patients had one-quadrant, 25 had two-quadrant, 17 had three-quadrant and 13 had four-quadrant calcification. The calcification was superficial in 42 patients, deep in 13 and both superficial and deep in 31. The axial length of calcium could be measured in 29 patients; it was < or = 5 mm in 11 and > or = 6 mm in 18. Fluoroscopy detected calcification in 50 patients (48%, p < 0.001 vs. detection by ultrasound); this proportion increased to 74% in patients with calcification of two or more quadrants and to 86% in patients with calcification > or = 6 mm in length of two or more quadrants. Calcification was more common in patients who smoked and tended to be more common in patients with multivessel disease or previous coronary artery bypass graft surgery.

CONCLUSIONS

We conclude that target lesion calcification occurs in 75% of patients with symptomatic coronary artery disease requiring angioplasty. Target lesion calcification is best detected, localized and quantified by intravascular ultrasound. These observations may be important in selecting devices for transcatheter therapy.