Cardiometabolic predictors of quantitative high-risk plaque features in a diverse patient population

Background/Introduction

Little is known about the prevalence of high-risk plaque features or cardiometabolic predictors in diverse patient populations with underrepresented minorities, in the setting of stable chest pain.

Purpose

The goals of our study are to 1) describe plaque characteristics in a diverse patient population with underrepresented minorities and 2) characterize cardiometabolic risk factors associated with high prevalence of high-risk quantitative low attenuation noncalcified plaque (LDNCP) burden.

Methods

Our study included patients with chest pain undergoing CCTA between June 2016 and October 2021 for stable chest pain, who had a complete cardiometabolic panel including lipoprotein(a) and lipid panel, and at least one blood pressure recording before CCTA. Patients with prior PCI or CABG where excluded. CACS was performed before CCTA as per Agatston method and quantified in Agatston Units (AU). Stenosis was graded as per SCCT guidelines by cardiologists and radiologists with level 3 cardiac CT expertise. Plaque measurements were performed using previously validated semiautomated software (AutoPlaque version 2.5) in all patients with CAD-RADS >0 by expert readers blinded from patients' characteristics. Coronary atherosclerotic plaque volumes were measured. Independent predictors for plaque on CCTA among patients were examined using Wilcox multivariate logistic regression.

Results

A total of 227 consecutive patients were included in our study (see table; age 55.00 [47.50–62.00] years, 63% female, 16% diabetes, 44% hypertension, 40% hyperlipidemia and 32% with current or previous smoking history). Majority of patients were Hispanic (64%) and the rest were Black (27%), White (6%) and Asian (3%).

Patients with LDNCP burden >4% were older (60.00 [52.00–66.50] vs 53.00 [43.75–61.00]; p<0.001), more likely to be diabetic (27.7 vs 11.5%; p=0.005), hypertensive (67.7 vs 33.8%; p<0.001), hyperlipidemic (64.6 vs 29.9%; p<0.001) and present smokers (31.3 vs 13.9%; p=0.003). Almost all patients (63/67) with LDNCP burden >4% had non-obstructive disease (CAD-RADS<4).

Patient with LDNCP burden >4% were more likely to be on statin therapy (46.0 vs 30.4%; p=0.041). There was no differences in ethnicity, hemoglobin A1C, TC, LDL-C, HLD-C, TGs, lipoprotein(a), SBP or DBP.

By logistic regression analysis, age (OR [CI]: 1.06 [1.01–1.08]), hypertension (2.20, [1.06–4.63]) and hyperlipidemia (2.73 [1.37–5.47]) increased the likelihood of LDNCP burden >4%, but not Lipoprotein (a)>175 nmol/L (OR [CI]: 1.07 [0.48–2.31].

Conclusions

In our cohort of patients with high number of unrepresented minorities presenting with stable chest pain, almost all patients (94%) with LDNCP burden >4% had non-obstructive CAD (CAD-RADS<4). There were no differences in prevalence of LDNCP or CAD-RADS among different ethnic groups. Age, hypertension and hyperlipidemia, were the cardiometabolic factors related to LDNCP burden >4%.

Funding Acknowledgement

Type of funding sources: None.

Management impacts on the dissolved organic carbon release from deadwood, ground vegetation and the forest floor in a temperate Oak woodland

The forest floor is often considered the most important source of dissolved organic carbon (DOC) in forest soils, yet little is known about the relative contribution from different forest floor layers, understorey vegetation and deadwood. Here, we determine the carbon stocks and potential DOC production from forest materials: deadwood, ground vegetation, leaf litter, the fermentation layer and top mineral soil (Ah horizon), and further assess the impact of management. Our research is based on long-term monitoring plots in a temperate deciduous woodland, with one set of plots actively managed by thinning, understorey scrub and deadwood removal, and another set that were not managed in 23 years. We examined long-term data and a spatial survey of forest materials to estimate the relative carbon stocks and concentrations and fluxes of DOC released from these different pools. Long-term soil water monitoring revealed a large difference in median DOC concentrations between the unmanaged (43.8 mg L^-1) and managed (18.4 mg L^-1) sets of plots at 10 cm depth over six years, with the median DOC concentration over twice as high in the unmanaged plots. In our spatial survey, a significantly larger cumulative flux of DOC was released from the unmanaged than the managed site, with 295.5 and 230.3 g m^-2, respectively. Whilst deadwood and leaf litter released the greatest amount of DOC per unit mass, when volume of the material was considered, leaf litter contributed most to DOC flux, with deadwood contributing least. Likewise, there were significant differences in the carbon stocks held by different forest materials that were dependent on site. Vegetation and the fermentation layer held more carbon in the managed site than unmanaged, whilst the opposite occurred in deadwood and the Ah horizon. These findings indicate that management affects the allocation of carbon stored and DOC released between different forest materials.

Association of coronary artery calcium score groups with qualitative and quantitatively assessed adverse plaque

Introduction

Coronary artery calcification is a marker of cardiovascular risk, but its association with qualitatively and quantitatively assessed plaque subtypes on coronary computed tomography (CT) angiography (CCTA) is unknown.

Methods

In this post-hoc analysis, CT images and clinical outcomes were assessed in SCOT-HEART trial participants. Agatston coronary artery calcium score (CACS) was measured on non-contrast CT and was stratified as zero (0 Agatston units, AU), minimal (1 to 9AU), low (10 to 99AU), moderate (100 to 399AU), high (400 to 999AU) and very high (≥1000AU). Adverse plaques were investigated with qualitative (visual categorisation of positive remodelling, low-attenuation plaque, spotty calcification, napkin ring sign) and quantitative (calcified, non-calcified, low-attenuation and total plaque burden) methods.

Results

Images of 1769 patients were assessed (mean age 58±9 years, 56% male, median Agatston score 21 [interquartile range 0 to 230] AU). Of these 36% had a zero, 9% minimal, 20% low, 17% moderate, 10% high and 8% very high CACS. Amongst patients with a zero CACS, 14% had nonobstructive disease, 2% had obstructive disease, 2% had visually assessed adverse plaques and 13% had quantitative low-attenuation plaque (LAP) burden >4% (Figure 1). Non-calcified and low-attenuation plaque burden increased between patients with zero, minimal and low CACS (p<0.001), but there was no difference between those with medium, high and very high CACS. Over a median follow-up of 4.8 [4.1 to 5.7] years, fatal or non-fatal myocardial infarction occurred in 41 patients, 10% of whom had zero CACS. CACS ≥1000AU (Hazard ratio (HR) 4.55 [1.20 to 17.3], p=0.026) and low-attenuation plaque burden (HR 1.74 [1.19 to 2.54], p=0.004) were the only predictors of myocardial infarction, independent of obstructive disease and cardiovascular risk score. Figure 2 shows example CCTA images in a patient with zero CACS, non-calcified plaque (red), low attenuation plaque (orange) burden >4% and obstructive disease in the left anterior descending coronary artery.

Conclusions

In patients with stable chest pain, a zero CACS is associated with a good prognosis, but 1 in 6 have coronary artery disease, including the presence of adverse plaques.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): British Heart Foundation, National Institute of Health/National Heart, Lung, and Blood Institute

P861A quantitative CCTA evaluation in non-obstructive coronary artery disease for the diagnosis of vessel-specific ischemia: results from the prospective, multicenter, international CREDENCE trial

Aim

To improve the diagnosis of coronary vessel-specific ischemia in non-obstructive coronary artery disease (CAD) using a quantitative whole-heart coronary computed tomography angiography (CCTA) evaluation. To date, predictors of ischemia in non-obstructive CAD remain underexplored.

Methods

Within the CREDENCE trial, 612 patients with suspected CAD at 13 sites (64±10 years, 70% men) underwent coronary computed tomography angiography (CCTA) and invasive coronary angiography with 3-vessel fractional flow reserve (FFR) measurements. For this specific analysis, only vessels with non-obstructive plaque (1–49% maximal diameter stenosis) by CCTA were included. The primary endpoint was coronary vessel-specific ischemia which was defined as FFR ≤0.80 (or ≥90% stenosis). Multivariable logistic regression modeling was performed to evaluate the effect of quantitative CCTA features beyond coronary stenosis on the prevalence of vessel-specific ischemia.

Results

FFR ≤0.80 (or ≥90% stenosis) was prevalent in 22.8% of 1,102 vessels with non-obstructive plaque. Using a step-wise approach, in addition to diameter stenosis (χ2=72), non-calcified PAV (χ2=126, P<0.001), lumen volume (χ2=175, P<0.001) and number of lesions with >30% stenosis (χ2=187, P=0.001) were independent CCTA-predictors of coronary vessel-specific ischemia (Figure 1). In the final model, diameter stenosis was no longer significantly associated with ischemia (P=0.236).

Figure 1

Conclusion

In vessels with non-obstructive plaque on CCTA, ischemia was present in approximately 20%. Measures of overall non-calcified plaque burden and smaller lumen volume were more important determinants of vessel-specific ischemia than maximal diameter stenosis.

Acknowledgement/Funding

NIH R01-HLL118019; Dalio Foundation and Michael J. Wolk Foundation

P6165Sex differences in compositional plaque volume progression in patients with stable coronary artery disease: observations from a serial CCTA registry

Background

It is unclear whether sex impacts the plaque volume (PV) progression in patients with stable coronary artery disease (CAD).

Purpose

To explore whether the total and compositional PV progression rate differ according to sex.

Methods

We performed a prospective multinational registry of consecutive patients who underwent serial CCTA at ≥2-year interval. Total and compositional PV at baseline and follow-up were quantitatively analysed and normalized using the analysed total vessel length. Multivariate linear regression models were constructed for each women and men.

Results

Of the 1,255 patients included (median CT interval 3.8 years), 543 were women and 712 were men. Women were older (62±9 years vs. 59±9 years, p<0.001) and had higher total cholesterol level (195±41mg/dL vs. 187±39mg/dL, p=0.002). Prevalence of hypertension, diabetes, and family history of CAD were not different (all p>0.05).

At baseline, men possessed greater total PV (131.5±230.5mm3 vs. 97.7±193.6mm3, p=0.005) and a higher prevalence of high-risk plaques (HRP) than women (31% vs. 20%, p<0.001). Annual total PV progression rate was greater in men, driven by the greater non-calcified PV progression (TABLE).

In multivariate analysis (TABLE), although total PV progression rate was not different, women were associated with greater calcified PV progression (β=2.83, p=0.004) but slower non-calcified PV progression (β=-3.39, p=0.008) and less development of HRP (β=-0.18, p=0.049) than men.

CCTA findings according to sex Univariate analysis Female Sex in Multivariable Analysis Women (n=543) Men (n=712) P β SE P Agatston CACS, /year 0.44±0.7 0.4±0.7 0.332 0.106 0.04 0.006 Total PVnormalized, mm3/year 14.7±23.4 17.8±26.2 0.026 -0.56 1.33 0.677 Calcified PVnormalized, mm3/year 10.5±21.5 10.0±19.1 0.670 2.83 0.98 0.004 Non-calcified PVnormalized, mm3/year 4.2±17.3 7.8±21.2 0.001 -3.39 1.28 0.008 Development of high-risk plaque*, n (%) 86 (15.8) 139 (19.5) 0.092 -0.18 0.09 0.049 In linear multivariate regression analysis adjusted with age, race, HTN, DM, family history, smoking, LDL, statin, anti-platelets, beta-blockers, and PV at baseline, women were associated with greater calcified PV progression and slower non-calcified PV progression. (High-risk plaque was defined as ≥2 of low-attenuation plaque, spotty calcification, and positive remodelling.)

Conclusion

In this large CCTA cohort, we found that the compositional PV progression differs according to sex. These findings, which are hypothesis generating, suggest that comprehensive plaque evaluation may contribute to further refine risk stratification according to sex.

Acknowledgement/Funding

This work was supported by the National Research Foundation of Korea funded by the Ministry of Science and ICT (Grant No. 2012027176).

P6162Difference in progression to obstructive lesions according to the presence of high-risk plaque features

Background

It is still debatable whether the so-called high-risk plaque (HRP) simply represents a certain phase during the natural history of coronary atherosclerotic plaques or the disease progression would differ according to the presence of HRP.

Purpose

We determined whether the pattern of non-obstructive lesion progression into obstructive lesions would differ according to the presence of HRP.

Methods

Patients with non-obstructive coronary artery disease, defined as % diameter stenosis (%DS) ≥50%, were enrolled from a prospective, multinational registry of consecutive patients who underwent serial coronary computed tomography angiography at an inter-scan interval of ≥2 years. HRP was defined as lesions with ≥2 of positive remodelling, spotty calcification, and low-attenuation plaque. The total and compositional percent atheroma volume (PAV) at baseline and annualized PAV change were compared between non-HRP and HRP lesions.

Results

A total of 1,115 non-obstructive lesions were identified from 327 patients (61.1±8.9 years old, 66.0% male). There were 690 non-HRP and 425 HRP lesions. HRP lesions possessed greater PAV and %DS at baseline compared to non-HRP lesions. However, the annualized total and non-calcified PAV change were greater in non-HRP lesions than in HRP lesions. On multivariate analysis, addition of baseline PAV and %DS to clinical risk factors improved the predictive power of the model (Table). When clinical risk factors, PAV, %DS, and HRP were all adjusted on Model 3, only baseline PAV and %DS independently predicted the development of obstructive lesions (hazard ratio (HR) 1.046 [95% confidence interval (CI): 1.026–1.066] and HR 1.087 [95% CI: 1.055–1.119], respectively, all p<0.001), while HRP did not (p>0.05).

Comparison of C-statistics of per-lesion analysis to predict progression to obstructive lesion C-statistics (95% CI) P Model 1: Baseline PAV 0.880 (0.879–0.884) – Model 2: Model 1 + baseline %DS 0.938 (0.937–0.939) vs. Model 1: <0.001 Model 3: Model 2 + HRP 0.935 (0.934–0.937) vs. Model 2: 0.004 Adjusted for age, male sex, hypertension, diabetes mellitus, hyperlipidemia, family history of coronary artery disease, smoking, body mass index, and statin use.

Conclusion

The pattern of individual coronary atherosclerotic plaque progression differed according to the presence of HRP. Baseline PAV was the most important predictor for lesions developing into obstructive lesions rather than the presence of HRP features at baseline.

Acknowledgement/Funding

This work was supported by the National Research Foundation of Korea funded by the Ministry of Science and ICT (Grant No. 2012027176).

P868Temporal remodeling of coronary arteries during progression of atherosclerosis with serial coronary CT angiography using 3D metrics: results from the PARADIGM study

Aim

To determine compensatory enlargement and luminal reduction of coronary arteries during the progression of atherosclerosis with serial coronary computed tomography angiography (CCTA) by using volumetric measurements. To date, the impact of coronary plaque progression on temporal remodeling, as opposed to the static remodeling, has only been studied with invasive imaging modalities and primarily two-dimensional areas rather than three-dimensional volumes.

Methods

In total, 1,245 patients with suspected coronary artery disease (CAD) at 13 sites (61±9 years, 39% women) underwent serial CCTA with interscan interval of ≥2 years. The primary objective was to assess volumetric temporal remodeling, defined as the linear association between the change in coronary plaque, lumen and vessel volume at follow-up CCTA on a per-segment level. Temporal remodeling was determined in strata of low and high baseline plaque burden as well as different coronary segments at baseline. Linear regression analysis and Pearson's correlation coefficients were calculated to assess associations.

Results

Amongst 1,245 patients with 19,920 segments, the median interscan interval was 3.3 (IQR 2.6–4.8) years. For each 1 mm3 increase in plaque volume, the increase in vessel volume was 0.72 mm3 and the decrease in lumen volume was 0.28 mm3 (Figure 1, both p<0.001). Volumetric temporal remodeling was similar in low versus high PAV [0.70 mm3 vs 0.73 mm3 (p for interaction=0.491)] and left-main arteries versus all other segments [0.78 mm3 vs. 0.72 mm3 (p for interaction=0.336)], but not in proximal versus distal segments at baseline [0.75 mm3 vs. 0.61 mm3 (p for interaction=0.020)].

Figure 1. Volumetric temporal remodeling

Conclusion

In general, coronary plaque grows approximately 70% outward and 30% into the coronary lumen during the progression of atherosclerosis. Volumetric temporal remodeling is not limited by baseline plaque burden, but is potentially dependent on its location within the coronary artery tree.

Acknowledgement/Funding

NRF of Korea (Grant No. 2012027176); Dalio Institute of Cardiovascular Imaging and Michael J. Wolk Foundation

4182Sex specific patterns in the onset and manifestation of coronary atherosclerotic plaque; insights from the multi-center CCTA CONFIRM registry

Background

Pathobiologic data support varied atherosclerotic plaque characteristics which uniquely define risk in women as compared to men (i.e., plaque erosion versus rupture). The advent of noninvasive coronary computed tomographic angiography (CCTA) allows for further exploration as to a sex-specific signature of atherosclerotic plaque features unique to women and different from that of men. In this analysis, we compared sex differences in the age of onset of coronary atherosclerosis and varied plaque findings between women and men.

Methods

From the multicenter CONFIRM registry, the Leiden CCTA score (based on segmental plaque extent, location, severity, and composition) was calculated in women and men without prior CAD, with imputation for missing plaque data. First, women and men were matched on the Leiden CCTA score to allow assessment of differences in atherosclerotic profile. Second, the earliest age of women and men to display a median Leiden CCTA score >0, >2, >6, >8 was evaluated. Third, the prognostic value of previously established thresholds of the Leiden CCTA score was examined for all-cause mortality with Cox-proportional hazard analysis, and specifically a sex interaction.

Results

In total, 11,678 women (age 58.5±12.4 years) and 13,272 men (age 55.6±12.5 years) were included. Of the patient subset matched on Leiden CCTA score (10,266 women, score 4.1±6.0 and 10,266 men, Leiden score 4.1±6.0, P=0.589), women were characterized by less obstructive CAD (≥50% stenosis) (17.5% vs 19.1%, P=0.003), more frequent non-obstructive left main plaque (10.1% vs 8.9%, P=0.004) and a lower number of segments with non-calcified or mixed plaque, but an equal number of calcified plaques. The earliest age when women and men have a median Leiden CCTA score above 0, 2, 4, 6, or 8 was consistently 14 to 16 years later for women. A visual representation of the CAD development delay is shown in Figure 1. Adjusted for age, the hazard ratio for death (827 events) for a score 6–20, and >20 (compared with 0–6) was 1.95 (95% CI 1.56–2.42), and 3.44 (95% CI 2.40–4.93) for women, respectively, and 1.63 (95% CI 1.31–2.03), 2.22 (95% CI 1.64–3.00) for men, respectively (P-interaction 0.006). Despite the low number of events, women <50 years with a score >20 were at 12.8 (95% CI 3.58–45.73) times increased risk.

Conclusion

There is an approximate 15-year delay in onset of coronary atherosclerosis for women compared to men. The burden of atherosclerotic plaque is associated with a higher relative hazard for death among women than men. The pattern of more nonobstructive CAD, especially in the left main coronary artery, but also less non-calcified plaque supports a sex-specific plaque signature which may uniquely define risk among women as compared to men.

Acknowledgement/Funding

The research reported in this manuscript was funded, in part, by the National Institute of Health (Bethesda, MD, USA) under award number R01 HL115150.

Appropriate use of noninvasive ischemia testing to guide revascularization decision making following acute ST elevation myocardial infarction in Latin American countries: Results from an expert panel meeting of the International Atomic Energy Agency

Across Latin American and Caribbean countries, cardiovascular disease and especially ischemic heart disease is currently the main cause of death both in men and in women. For most Latin American and Caribbean countries, public and community health efforts aim to define care strategies which are both clinically and cost effective and promote primary and secondary prevention, resulting in improved patient outcomes. The optimal approach to deal with acute events such as ST-elevation myocardial infarction (STEMI) is a matter of controversy; however, there is an expanding role for assessing residual ischemic burden in STEMI patients following primary percutaneous coronary intervention. Although randomized clinical trials have established the value of staged fractional flow reserve-guided revascularization, the use of noninvasive functional imaging modalities may play a similar role at a much lower cost. For LAC, available stress imaging techniques could be applied to define residual ischemia in the non-infarct related artery and to target revascularization in a staged procedure after primary percutaneous coronary intervention The use of nuclear cardiac imaging, supported by its relatively wide availability, moderate cost, and robust quantitative capabilities, may serve to guide effective care and to reduce subsequent cardiac events in patients with coronary artery disease. This noninvasive approach may avert potential safety issues with repeat and lengthy invasive procedures, and serve as a baseline for subsequent follow-up stress testing following the index STEMI event. This consensus document was devised from an expert panel meeting of the International Atomic Energy Agency, highlighting available evidence with a focus on the utility of stress myocardial perfusion imaging in post-STEMI patients. The document could serve as guidance to the prudent and appropriate use of nuclear imaging for targeting therapeutic management and avoiding unnecessary invasive procedures within Latin American and Caribbean countries, where resources could be scarce.

Adsorption of Pb and Zn from binary metal solutions and in the presence of dissolved organic carbon by DTPA-functionalised, silica-coated magnetic nanoparticles

The ability of diethylenetriaminepentaacetic acid (DTPA)-functionalised, silica-coated magnetic nanoparticles to adsorb Pb and Zn from single and bi-metallic metal solutions and from solutions containing dissolved organic carbon was assessed. In all experiments 10 mL solutions containing 10 mg of nanoparticles were used. For single metal solutions (10 mg L^-1 Pb or Zn) at pH 2 to 8, extraction efficiencies were typically >70%. In bi-metallic experiments, examining the effect of a background of either Zn or Pb (0.025 mmol L^-1) on the adsorption of variable concentrations (0-0.045 mmol L^-1) of the other metal (Pb or Zn, respectively) adsorption was well modelled by linear isotherms (R² > 0.60; p ≤ 0.001) and Pb was preferentially adsorbed relative to Zn. In dissolved organic carbon experiments, the presence of fulvic acid (0, 2.1 and 21 mg DOC L^-1) reduced Pb and Zn adsorption from 0.01, 0.1 and 1.0 mmol L^-1 solutions. However, even at 21 mg DOC L^-1 fulvic acid, extraction efficiencies from 0.01 to 0.1 mmol L^-1 solutions remained >80% (Pb) and >50% (Zn). Decreases in extraction efficiency were significant between initial metal concentrations of 0.1 and 1.0 mmol L^-1 indicating that at metal loadings between c. 100 mg kg^-1 and 300 mg kg^-1 occupancy of adsorption sites began to limit further adsorption. The nanoparticles have the potential to perform effectively as metal adsorbents in systems containing more than one metal and dissolved organic carbon at a range of pH values.

HIV, highly active antiretroviral therapy and the heart: a cellular to epidemiological review

The advent of potent highly active antiretroviral therapy (HAART) for persons infected with HIV-1 has led to a "new" chronic disease with complications including cardiovascular disease (CVD). CVD is a significant cause of morbidity and mortality in persons with HIV infection. In addition to traditional risk factors such as smoking, hypertension, insulin resistance and dyslipidaemia, infection with HIV is an independent risk factor for CVD. This review summarizes: (1) the vascular and nonvascular cardiac manifestations of HIV infection; (2) cardiometabolic effects of HAART; (3) atherosclerotic cardiovascular disease (ASCVD) risk assessment, prevention and treatment in persons with HIV-1 infection.

Does ochre have the potential to be a remedial treatment for As-contaminated soils?

Ochre is an iron oxyhydroxide-rich waste that accumulates in water bodies associated with disused mines. Laboratory experiments were conducted to examine the potential of four different ochres to be used as remedial agents for As contaminated soils. The ochres removed As from solution (200 and 500 mg L(-1)) in adsorption experiments at pH 3 and 8 and, when added to As contaminated soil (5% w/w) significantly reduced As release to solution. In both these experiments the highest surface area ochres performed best. The impact of ochre amendments on uptake of As from soil by plants and humans and release of As to ground water was assessed in a year-long incubation study. Ochres increased soil pH and reduced CaCl2 extractable As but had no consistent effect on plant growth, plant As uptake or As extraction in physiologically-based extraction tests. Ochre may be better used for water treatment than soil remediation.

SPECT/PET myocardial perfusion imaging versus coronary CT angiography in patients with known or suspected CAD

Stress SPECT myocardial perfusion imaging (MPI) is the most commonly utilized stress imaging technique for patients with suspected or known coronary artery disease (CAD) and has a robust evidence base including the support of numerous clinical guidelines. Gated SPECT is a well-established noninvasive imaging modalities that is a core element in evaluation of patients with both acute and stable chest pain syndromes. Over the past decade, PET has become increasingly used for the same applications. By comparison, cardiac computed tomography (CT) is a more recently developed method, providing non-invasive approaches for imaging coronary atherosclerosis and coronary artery stenosis. Non-contrast CT for imaging the extent of coronary artery calcification (CAC), in clinical use since the mid-1990's, has a very extensive evidence base supporting its use in CAD prevention. While contrast-enhanced CT for noninvasive CT coronary angiography (CCTA) is relatively new, it has already developed an extensive base of evidence regarding diagnosing obstructive CAD and more recently evidence has emerged regarding its prognostic value. It is likely that non-contrast CT or CCTA for assessment of extent of atherosclerosis will become an increasing part of mainstream cardiovascular imaging practices as a first line test. In some patients, further ischemia testing with MPI will be required. Similarly, MPI will continue to be widely used as a first-line test, and in some patients, further anatomic definition of atherosclerosis with CT will also be appropriate. This review will provide a synopsis of the available literature on imaging that integrates both CT and MPI in strategies for the assessment of asymptomatic patients for their atherosclerotic coronary disease burden and risk as well as symptomatic patients for diagnosis and guiding management. We propose possible strategies through which imaging might be used to identify asymptomatic candidates for more intensive prevention and risk factor modification strategies as well as symptomatic patients who would benefit from referral to invasive coronary angiography for consideration of revascularization.

Impact of contrast echocardiography on diagnostic algorithms: pharmacoeconomic implications

The major goal of medicine in the era of managed care is to control escalating costs and to attain a high level of quality health care. Capitation has limited access to expensive and unnecessary testing, placing an emphasis on the prudent use of available technology. A vast armamentarium of available diagnostic screening tests are available within cardiology. Routine two-dimensional (2-D) echocardiography is a high-quality, low-cost test that provides enhanced portability and real-time test interpretation over other noninvasive test modalities. The echocardiogram may cost up to 50% less than competitive nuclear single-photon emission computed tomography (SPECT) imaging. However, on average 10% of routine and 33% of stress echocardiograms are suboptimal (disproportionately affecting obese patients and those with lung disease). Myocardial contrast echocardiography has been shown to provide enhanced endocardial border delineation and left ventricular opacification, to enhance Doppler signal, and to provide information on myocardial perfusion. In several recent phase II and III studies, the use of a contrast agent has been shown to improve the diagnostic accuracy of echocardiography substantially. Improvements in the diagnostic capabilities of echocardiography have been shown to (1) impact upon downstream repetitive testing in patients with an initially nondiagnostic echocardiogram, (2) potentially increase laboratory throughput, and (3) reduce the rate of false-positive and negative tests as a result of improved image quality. As clinical and cost-effectiveness parallel one another, the use of myocardial contrast echocardiography in selected patient cohorts will result in improved diagnostic accuracy and a cost-effective pattern of care.

Coronary heart disease in women: update 2008

Coronary heart disease (CHD) remains the leading cause of mortality for US women, responsible for almost 250,000 deaths annually. Preventive heart-health behavioral changes by women and aggressive coronary risk reduction can decrease the number of women disabled and killed by CHD. Angina is the predominant initial and subsequent presentation of CHD in women; categorization of chest pain and risk stratification of women assume pivotal roles. A robust evidence-based algorithm can guide cardiovascular imaging techniques to evaluate women with suspected myocardial ischemia to detect those with worsened survival. Restricted functional capacity (<5 METs) is a consistent marker of worsened prognosis. Younger women have substantially higher mortality rates than men following myocardial infarction and coronary bypass surgery. Although these women have more comorbidity and risk factors, other issues including biological differences, treatment differences, and psychosocial factors require management strategies tailored to the unique needs of women.

Biochemical and bioimaging markers for risk assessment and diagnosis in major cardiovascular diseases: a road to integration of complementary diagnostic tools

This report from the first International Course on Integrated Biomarkers, Biochemical and Bioimaging Endpoints in Cardiovascular Diagnosis, Prevention, Therapy and Drug Development provides the basis for optimizing diagnostic, prognostic and therapeutic information in four areas of cardiovascular medicine: primary prevention of cardiovascular diseases, acute coronary syndromes, heart failure and stroke. Risk stratification and treatment strategies can be refined and enhanced through integration of bioimaging and biochemical markers to characterize sub-clinical and clinical atherosclerosis. For the integrative approach to be useful, each of the biomarkers must be validated and cost-effective. Clinical decision is the primary level of integration and is based on clinical evaluation and the use of a combination of bioimaging and biochemical markers. The decision to initiate preventive or therapeutic intervention must take into account the factors affecting the levels of expression of the biomarker and the potential input the biomarker has on metabolic processes or modulation of other biomarkers. The optimal approach to intervention must take into consideration the risk-benefit and cost-effectiveness ratios.

Diagnostic and prognostic value of non-invasive imaging in known or suspected coronary artery disease

The role of non-invasive imaging techniques in the evaluation of patients with suspected or known coronary artery disease (CAD) has increased exponentially over the past decade. The traditionally available imaging modalities, including nuclear imaging, stress echocardiography and magnetic resonance imaging (MRI), have relied on detection of CAD by visualisation of its functional consequences (i.e. ischaemia). However, extensive research is being invested in the development of non-invasive anatomical imaging using computed tomography or MRI to allow detection of (significant) atherosclerosis, eventually at a preclinical stage. In addition to establishing the presence of or excluding CAD, identification of patients at high risk for cardiac events is of paramount importance to determine post-test management, and the majority of non-invasive imaging tests can also be used for this purpose. The aim of this review is to provide an overview of the available non-invasive imaging modalities and their merits for the diagnostic and prognostic work-up in patients with suspected or known CAD.

Diagnostic and clinical perspectives of fusion imaging in cardiology: is the total greater than the sum of its parts?

Positron emission tomography, cardiovascular magnetic resonance and multislice computed tomography have contributed to changing our pathophysiological understanding of many conditions. Clinically, they have provided new tools for the identification of preclinical disease and a better understanding of how disease progresses. The application of these imaging modalities to preclinical disease and the use of these techniques in patients with overt cardiovascular disease are reviewed.

Myocardial perfusion scintigraphy: the evidence

This review summarises the evidence for the role of myocardial perfusion scintigraphy (MPS) in patients with known or suspected coronary artery disease. It is the product of a consensus conference organised by the British Cardiac Society, the British Nuclear Cardiology Society and the British Nuclear Medicine Society and is endorsed by the Royal College of Physicians of London and the Royal College of Radiologists. It was used to inform the UK National Institute of Clinical Excellence in their appraisal of MPS in patients with chest pain and myocardial infarction. MPS is a well-established, non-invasive imaging technique with a large body of evidence to support its effectiveness in the diagnosis and management of angina and myocardial infarction. It is more accurate than the exercise ECG in detecting myocardial ischaemia and it is the single most powerful technique for predicting future coronary events. The high diagnostic accuracy of MPS allows reliable risk stratification and guides the selection of patients for further interventions, such as revascularisation. This in turn allows more appropriate utilisation of resources, with the potential for both improved clinical outcomes and greater cost-effectiveness. Evidence from modelling and observational studies supports the enhanced cost-effectiveness associated with MPS use. In patients presenting with stable or acute chest pain, strategies of investigation involving MPS are more cost-effective than those not using the technique. MPS also has particular advantages over alternative techniques in the management of a number of patient subgroups, including women, the elderly and those with diabetes, and its use will have a favourable impact on cost-effectiveness in these groups. MPS is already an integral part of many clinical guidelines for the investigation and management of angina and myocardial infarction. However, the technique is underutilised in the UK, as judged by the inappropriately long waiting times and by comparison with the numbers of revascularisations and coronary angiograms performed. Furthermore, MPS activity levels in this country fall far short of those in comparable European countries, with about half as many scans being undertaken per year. Currently, the number of MPS studies performed annually in the UK is 1,200/million population/year. We estimate the real need to be 4,000/million/year. The current average waiting time is 20 weeks and we recommend that clinically appropriate upper limits of waiting time are 6 weeks for routine studies and 1 week for urgent studies.

Diagnostic, prognostic, and cost assessment of coronary artery disease in women

Women with obstructive coronary disease appear to be more challenging diagnostically and suffer a more adverse prognosis than men. More than one half of women with symptoms of ischemic heart disease have no obstructive coronary artery disease at coronary angiography, yet these women frequently have persistent symptom-related disability and consume large amounts of healthcare resources. Prior evidence has been limited regarding effective diagnostic strategies for the assessment of symptomatic women. The current report synthesizes existing evidence on diagnostic testing in women, including research from the ongoing National Heart, Lung, and Blood Institute-sponsored Women's Ischemia Syndrome Evaluation (WISE) study. In addition to recent published evidence (drawn from much larger cohorts of women) that stress echocardiography and nuclear imaging are similar in their ability to risk-stratify women, the WISE study is exploring new pathophysiological mechanisms of microvascular dysfunction in women. An unfolding body of evidence suggests that as tests become more diagnostically and prognostically accurate, the process will become more cost efficient. The results from a growing number of large observational series and National Institutes of Health-sponsored studies are expected to be the foundation for cost-effective diagnostic and prognostic strategies for the approximately 5 million women who undergo evaluation for coronary disease annually.

The HCA National Disease Management Program for coronary disease detection and treatment in women

The diagnosis and treatment of heart disease in women continues to be one of the greatest challenges facing cardiovascular medicine today. Marked reductions in mortality rates during the past 2 decades did not result in improved outcomes for women. A major rate-limiting step to improving mortality rates for women is early diagnosis and initiation of effective lifesaving therapies for women. In 1999, HCA Healthcare Systems, Inc, Nashville, TN, initiated a coordinated effort among 208 hospitals in 26 states to improve the diagnosis of coronary disease and to target women who should receive aggressive risk factor modification and referral to cardiologists. We describe the initial phases of program development, including employee risk factor screening; citywide health risk assessment; nationwide educational programs for clinicians, staff, and consumers; and a dedicated outcomes assessment program for tracking women at risk for coronary disease. We believe that these efforts provide a venue for optimal care and improved outcomes for women served by HCA facilities.

Evidence-based risk assessment in noninvasive imaging

Assessment of important clinical and economic outcomes has become central to the evaluation of patient care. Outcome research is deeply rooted in epidemiology, including the use of multivariable, risk-adjusted regression analysis. In our current health care environment, these methods are increasingly being used to assess the quality of care and to profile physicians and laboratories. Nuclear medicine physicians therefore need to better understand outcome methodologies in order to evaluate patient outcomes, develop guidelines, and decide on patient management.

METHODS

This review describes the methods of assessing the diagnostic and prognostic value of nuclear medicine techniques and, briefly, the methodologic limitations of sample size, frequency and type of events, and follow-up periods and the incremental value of imaging. Also described are logistic regression and Cox proportional hazards modeling. Models for risk assessment are designed to identify whether patients require conservative (i.e., low-risk) or aggressive (i.e., high-risk) treatment. Treatment selection is currently based on risk assessment and the formation of an integrated, empiric risk stratification algorithm of care. This review also includes the methods of assessing economic effectiveness and quality-of-life issues for patients examined with nuclear medicine techniques.

CONCLUSION

In this era of constrained resources, low-cost outpatient-based care may be of increasing importance. High-quality evidence of the clinical and economic outcome of nuclear imaging is essential for helping health care providers and payers assess its value.

Serial changes on quantitative myocardial perfusion SPECT in patients undergoing revascularization or conservative therapy

BACKGROUND

Little is known about changes of myocardial perfusion in patients undergoing coronary revascularization or medical therapy. The purpose of this observational study was to assess the long-term effects of revascularization or conservative therapy on serial quantitative myocardial perfusion single photon emission computed tomography (SPECT).

METHODS AND RESULTS

The study population consisted of 421 patients who underwent serial rest thallium-201/stress technetium-99m sestamibi dual-isotope myocardial perfusion SPECT with at least a 1-year interval between the 2 studies and who had abnormal quantitative scan results on the first stress SPECT. The mean interval between scans was 32.7 +/- 15.9 months. Patients were divided into 3 groups according to stress defect extent: group 1 had small stress defects (4%-10%, n = 145), group 2 had intermediate stress defects (>10%-20%, n = 144), and group 3 had extensive stress defects (>20%, n = 132) at baseline. Forty patients in group 1, 44 in group 2, and 54 in group 3 underwent coronary revascularization between 2 SPECT studies; the others had conservative therapy. In group 3 patients with revascularization, stress defect extent and reversible defect extent were remarkably reduced (14.5% +/- 13.6% and 13.1% +/- 12.5%, respectively; both P <.0001), with greater improvement in those patients reporting increased use of cardiac medications; resting defect extent was slightly reduced (1.9% +/- 6.4%, P <.05). In group 3 patients with conservative therapy, a small reduction in stress defect extent was noted (2.3% +/- 8.3%, P <.05). In group 2, there were modest, similar reductions in reversible defect extent in both the patients with revascularization (2.7% +/- 7.7%, P <.05) and those with conservative therapy (1.8% +/- 7.3%, P <.05), as well as a small but significant reduction in stress defect extent in those with conservative therapy (2.1% +/- 8.2%, P <.05). In group 1 patients, no significant changes in stress, rest, or reversible defect extent were found with either therapy.

CONCLUSIONS

The findings of this study show that improvement in quantitative myocardial perfusion abnormalities over time occurs in some patients with either revascularization or conservative therapy and suggest that, in patients with extensive defects, greater improvement may be seen in those who undergo revascularization.

Diagnostic strategies for women with suspected coronary artery disease

The clinician evaluating a woman with symptoms potentially indicative of coronary heart disease faces the challenge of choosing the appropriate diagnostic test. The use of noninvasive testing in women has been controversial due to a perception of diminished accuracy, limited female representation, and technical limitations that compromise efficacy. Recent meta-analyses and large observational series report marked improvements in accuracy for women undergoing exercise treadmill, echocardiography, and nuclear testing. Electron beam computed tomography is a relatively new technique, and the body of evidence is still developing. An adequate body of evidence supports the use of noninvasive testing for intermediate risk, symptomatic women and may result in improved diagnostic and therapeutic decision making.

Anatomy of a meta-analysis: a critical review of "exercise echocardiography or exercise SPECT imaging? A meta-analysis of diagnostic test performance"

BACKGROUND

Accurate diagnosis of coronary heart disease has the potential to contribute substantially to cost-effective delivery of health services. Recent work by Fleischmann et al (JAMA 1998;280:913-20) represents an effort to summarize the accuracy of exercise echocardiography and exercise single photon emission computed tomography (SPECT).

METHODS AND RESULTS

A critique of the previous work was constructed, obtaining the 44 articles used. These articles were reviewed and summarized with established techniques for meta-analysis. The studies summarized by Fleischmann et al were found to be significantly heterogeneous (echocardiography and SPECT, both P<.001). In the SPECT cohort, combination of different radioisotopes and reading techniques, and inclusion of reports using experimental techniques, were sources of heterogeneity. In the echocardiography cohort, experimental techniques and an individual series were identified. When the sample was stratified for sources of heterogeneity, it was found that there was no significant difference in diagnostic accuracy between the echocardiography and SPECT techniques used in current clinical practice. Meta-regression with summary receiver operating characteristic curve techniques, after adjustment of the model for multicolinearity and outliers, revealed that there were no significant differences between SPECT as used in current clinical practice and echocardiography.

CONCLUSION

The report by Fleischmann et al contains serious flaws that limit its validity and generalizability.

Noninvasive strategies for the estimation of cardiac risk in stable chest pain patients. The Economics of Noninvasive Diagnosis (END) Study Group

Effective allocation of medical resources in stable chest pain patients requires the accurate diagnosis of coronary artery disease and the stratification of future cardiac risk. We studied the relative predictive value for cardiac death of 3 commonly applied noninvasive strategies, clinical assessment, stress electrocardiography, and myocardial perfusion tomography, in a large, multicenter population of stable angina patients. The multicenter observational series comprised 7 community and academic medical centers and 8,411 stable chest pain patients. All patients underwent pretest clinical screening followed by stress (exercise 84% or pharmacologic 16%) electrocardiography and myocardial perfusion tomography. Risk-adjusted multivariable Cox proportional hazards models were developed to predict cardiac death. Kaplan-Meier rates of time to cardiac catheterization were also computed. Cardiac mortality was 3% during the 2.5 +/- 1.5 years of follow-up. The number of infarcted vascular territories and pretest clinical risk factors were strong predictors of cardiac mortality, whereas the number of ischemic vascular territories gained increasing importance when determining post-test resource use requirements (i.e., the decision to perform cardiac catheterization). Exertional ST-segment depression in a population with a high frequency of electrocardiographic abnormalities at rest was not a significant differentiator of cardiac death risk. Stable chest pain patients are accurately identified as being at high risk for near-term cardiac events by both physicians' screening clinical evaluation and by the results of stress myocardial perfusion imaging. Disease management strategies for stable chest pain patients aimed at risk reduction should incorporate knowledge of relevant end points in treatment and guideline development.

Clinical and economic outcomes assessment in nuclear cardiology

The future of nuclear medicine procedures, as understood within our current economic climate, depends upon its ability to provide relevant clinical information at similar or lower comparative costs. With an ever-increasing emphasis on cost containment, outcome assessment forms the basis of preserving the quality of patient care. Today, outcomes assessment encompasses a wide array of subjects including clinical, economic, and humanistic (i.e., quality of life) outcomes. For nuclear cardiology, evidence-based medicine would require a threshold level of evidence in order to justify the added cost of any test in a patient's work-up. This evidence would include large multicenter, observational series as well as randomized trial data in sufficiently large and diverse patient populations. The new movement in evidence-based medicine is also being applied to the introduction of new technologies, in particular when comparative modalities exist. In the past 5 years, we have seen a dramatic shift in the quality of outcomes data published in nuclear cardiology. This includes the use of statistically rigorous risk-adjusted techniques as well as large populations (i.e., > 500 patients) representing multiple diverse medical care settings. This has been the direct result of the development of multiple outcomes databases that have now amassed thousands of patients worth of data. One of the benefits of examining outcomes in large patient datasets is the ability to assess individual endpoints (e.g., cardiac death) as compared with smaller datasets that often assess combined endpoints (e.g., death, myocardial infarction, or unstable angina). New technologies for the diagnosis of coronary artery disease have contributed to the rising costs of care. In the United States and in Europe, costs of care have risen dramatically, consuming an ever-increasing amount of available resources. The overuse of diagnostic angiography often leads to unnecessary revascularization that does not lead to improvement in outcome. Thus, the potential exists that stress SPECT imaging, a highly effective diagnostic tool, could effect substantial change in reducing inappropriate use of an invasive procedure resulting in cost effective cardiac care. A synthesis of current economic evidence in gated SPECT imaging will be presented. In conclusion, a current state of the evidence review is presented on the clinical and economic data using nuclear cardiology imaging.

Economic aspects of transesophageal echocardiography and atrial fibrillation

Cardiovascular disease is the leading cause of complications and death in the United States, affecting nearly 60 million Americans in 1998 and costing an estimated $274.2 billion. A major contributor to the costs of cardiovascular disease is atrial fibrillation (AF). AF is the most common sustained arrhythmia and affects > 2.2 million people and approximately 5% of all persons over the age of 60. Transesophageal echocardiography (TEE) with short-term anticoagulation has been proposed as a viable strategy to guide patients with AF. Here, we (1) review the current environmental context for a TEE-guided approach, (2) summarize the existing literature on the economic aspects of TEE, and (3) outline an economic framework for an economic analysis of TEE investigation or any major clinical therapy. We conclude that more powerful analytical tools are evolving to analyze the important economic, clinical, and social aspects of a patient's medical encounter.

Contrast echocardiography: current and future applications

Recent updates in the field of echocardiography have resulted in improvements in image quality, especially in those patients whose ultrasonographic (ultrasound) evaluation was previously suboptimal. Intravenous contrast agents are now available in the United States and Europe for the indication of left ventricular opacification and enhanced endocardial border delineation. The use of contrast enables acquisition of ultrasound images of improved quality. The technique is especially useful in obese patients and those with lung disease. Patients in these categories comprise approximately 10% to 20% of routine echocardiographic examinations. Stress echocardiography examinations can be even more challenging, as the image acquisition time factor is critically important for accurate detection of coronary disease. Improvements in image quality with intravenous contrast agents can facilitate image acquisition and enhance delineation of regional wall motion abnormalities at the peak level of exercise. Recent phase III clinical trial data on the use of Optison and several other agents (currently under evaluation) have revealed that for approximately half of patients, image quality substantively improves, which enables the examination to be salvaged and/or increases diagnostic accuracy. For the "difficult-to-image" patient, this added information results in (1) enhanced laboratory efficiency, (2) a reduction in downstream testing, and (3) possible improvements in patient outcome. In addition, substantial research efforts are underway to use ultrasound contrast agents for assessment of myocardial perfusion. The detection of myocardial perfusion during echocardiographic examinations will permit the simultaneous assessment of global and regional myocardial structure, function, and perfusion-all of the indicators necessary to enable the optimal noninvasive assessment of coronary artery disease. Despite the added benefit in improved efficacy of testing, few data exist regarding the long-term effectiveness of these agents. Currently under evaluation are the clinical and economic outcome implications of intravenous contrast agent use for daily clinical decision making in a variety of patient subsets. Until these data are known, this document offers a preliminary synthesis of available evidence on the value of intravenous contrast agents for use in rest and stress echocardiography. At present, it is the position of this guideline committee that intravenous contrast agents demonstrate substantial value in the difficult-to-image patient with comorbid conditions limiting an ultrasound evaluation of the heart. For such patients, the use of intravenous contrast agents should be encouraged as a means to provide added diagnostic information and to streamline early detection and treatment of underlying cardiac pathophysiology. As with all new technology, this document will require updates and revisions as additional data become available.

Hospital resource consumption in patients with diabetes and multivessel coronary disease undergoing revascularization

OBJECTIVE

To identify factors responsible for the variation in real hospital costs and length of stay for patients with diabetes undergoing coronary angioplasty or coronary bypass surgery.

STUDY DESIGN

Retrospective study of patients with diabetes and coronary artery disease treated at a single hospital.

PATIENTS AND METHODS

The study population included 1809 patients with diabetes and multivessel (2-vessel or 3-vessel) coronary artery disease who underwent an initial coronary angioplasty or coronary bypass surgery between 1988 and 1996. After accounting for the extent and severity of the patient's coronary artery disease, a sequential model was used to assess if diabetic characteristics were independently associated with higher hospital resource utilization during revascularization.

RESULTS

Multivariate regression results indicated that for patients with diabetes who underwent coronary angioplasty, a baseline creatinine level of > or = 2.0 mg/dL was associated with significantly higher hospital costs and longer length of stay. For patients with diabetes who underwent a coronary bypass surgery only, a baseline creatinine level of > or = 2.5 mg/dL was associated with higher hospital costs and longer hospital length of stay.

CONCLUSIONS

After controlling for coronary risk factors, selected diabetes-specific characteristics are associated with higher hospital resource utilization. Risk adjustments in hospital reimbursement may be needed to assure that patients with diabetes who have cardiovascular disease have access to revascularization procedures.

Defining quality health care with outcomes assessment while achieving economic value

The effectiveness of a procedure is increasingly guided by the evaluation of patient outcomes. Outcomes data is used to develop clinical pathways of care and to define appropriate resource-use levels without sacrificing quality of care. Integration of the economic implications of medical services into an outcome-based guideline allows for the development of disease-management strategies. In cardiovascular medicine, risk reduction is associated with high cost due to the "pay-back" of new technologies and therapies. A major challenge is to define a balance between "high tech" care and cost. This paper devises an outpatient evidence-based guideline using clinical and economic outcomes data for the diagnosis of coronary disease.

Current evidence on diagnostic testing in women with suspected coronary artery disease: choosing the appropriate test

Marked reductions in cardiovascular mortality have been reported over the last 2 decades as a result of therapeutic advances in ischemic heart disease. Despite medical advances, case fatality rates are higher for women than men. A critical step toward improving outcomes is early diagnosis of coronary artery disease by noninvasive evaluation. The use of noninvasive testing in women has been controversial because of a perception of diminished accuracy, limited female representation, and compromise of efficacy of testing because of technical limitations (eg, thallium-201 breast artifact). Recent meta analysis and large observational series report marked improvements in the accuracy of results for women undergoing exercise treadmill, echocardiography, and nuclear testing. Exercise treadmill testing has an improved accuracy when multiple risk parameters (eg, ST deviation, chest pain, exercise time) are included in the test interpretation. For women, a low-risk Duke treadmill score is associated with a 97% 5-year survival, with 80% of these patients having no obstructive disease. Multivessel disease (70%) is common for those with a high-risk treadmill score with a 5-year survival of 90%. The diagnostic accuracy of electron beam computed tomography reveals a sensitivity and specificity of 88% and 49%. For exercise echocardiography, test diagnostic sensitivity and specificity are 86% and 79%. For nuclear imaging, 3-year cardiac survival ranged from 99% to 85% for 0 to 3 vascular territories with perfusion abnormalities. A sufficient body of evidence supports the use of noninvasive testing for intermediate-risk, symptomatic women. Diagnostic certainty may be effectively guided by the evaluation of global and regional wall motion, eg, with echocardiography. Risk assessment may be more precise with the evaluation of myocardial perfusion, eg, with stress nuclear imaging. With the use of updated evidence, informed test selection for women may result in improved diagnostic and therapeutic decision-making, with the use of available noninvasive testing modalities.

Prognostic value of thallium-201 single-photon emission computed tomography for patients with multivessel coronary artery disease after revascularization (the Emory Angioplasty versus Surgery Trial [EAST])

The aim of this study was to investigate the relation between reversible thallium single-photon emission computed tomography (SPECT) myocardial perfusion defects at 1-year after revascularization and quantitative indexes in Emory Angioplasty versus Surgery Trial (EAST) and outcomes 3 years after revascularization in 336 patients. EAST was a randomized controlled trial assessing cardiac outcomes for angioplasty versus bypass surgery for patients with multivessel coronary artery disease. During this prospective trial, a substudy included the evaluation of the prognostic value of reversible defects on quantitative thallium SPECT. At 1-year after revascularization, 336 patients underwent SPECT thallium-201 stress myocardial perfusion and 3-hour delayed imaging. Subsequent events, percutaneous transluminal coronary angioplasty, coronary artery bypass graft surgery, myocardial infarction, and death, were recorded at 3 years. A stress-induced reversible thallium-201 defect was defined using a quantitative index of a reversibility score >30% and severity score >500. Reversible defects were observed more frequently in the percutaneous transluminal coronary angioplasty than in the coronary artery bypass graft surgery treatment groups (46% vs 27%, p <0.001). A total of 123 patients had stress-induced, reversible thallium defects and more events than patients with other perfusion results (freedom from all events was 81.3% vs 94% [p <0.001], and freedom from myocardial infarction and death 88.3% vs 95.5% [p = 0.031]). Quantitative thallium SPECT at 1 year after revascularization risk stratifies patients as to their likelihood of major cardiac outcomes.

Incremental prognostic value of myocardial perfusion single photon emission computed tomography in patients with diabetes mellitus

BACKGROUND

Previous studies have shown that myocardial perfusion single photon emission computed tomography (SPECT) provides incremental prognostic information in the general population, but the prognostic efficacy of nuclear testing in patients with diabetes mellitus is unclear.

METHODS

We conducted a study with 1271 consecutively registered patients with diabetes and 5862 patients without diabetes with known or suspected coronary artery disease undergoing rest thallium 201/stress technetium 99m sestamibi dual-isotope myocardial perfusion SPECT with exercise or adenosine pharmacologic testing. Patients were followed up for at least 1 year. The successful follow-up rate was 92.4% for patients with diabetes and 94.0% for subjects without diabetes. The mean follow-up period was 23.7 +/- 7.7 months for the former group and 21.5 +/- 6.1 months for the latter.

RESULTS

Over the follow-up period, patients with diabetes had significantly higher rates of hard events (cardiac death or nonfatal myocardial infarction) (4.3% per year versus 2.3% per year, P <.001) and higher total event rates (hard events and late revascularization) (9.0% per year versus 5.3% per year, P <. 001) compared with rates among patients without diabetes. Cox proportional hazards analysis revealed that nuclear testing added incremental value over clinical and historical variables among patients with diabetes (global chi(2) increased 46% for the exercise group [n = 619] and 88% for the adenosine group [n = 461]; both P <. 001). The event rates rose significantly as a function of summed stress score and summed difference score among both patients with diabetes and patients without diabetes (P <.001). The patients with diabetes with normal scans had relatively low hard event rates (1% to 2% per year), those with mildly abnormal scans had intermediate hard event rates (3% to 4% per year), and those with moderately to severely abnormal scans had relatively high hard event rates (>7% per year).

CONCLUSIONS

The results of this study indicated that exercise and adenosine stress myocardial perfusion SPECT are valuable for risk stratification and management of patients with diabetes.

Early dipyridamole (99m)Tc-sestamibi single photon emission computed tomographic imaging 2 to 4 days after acute myocardial infarction predicts in-hospital and postdischarge cardiac events: comparison with submaximal exercise imaging

BACKGROUND

Because of its brief hemodynamic effects and minor effect on determinants of myocardial oxygen demand, vasodilator stress myocardial perfusion imaging (MPI) can be applied very early after acute myocardial infarction (AMI) for risk stratification, allowing management decisions to be made earlier and thus potentially shortening hospitalization stays, reducing costs, and preventing early cardiac events. This multicenter randomized trial compared the prognostic value of early dipyridamole MPI and standard predischarge submaximal exercise MPI in patients who presented with AMI.

METHODS AND RESULTS

Patients who presented with their first AMI (n=451) were randomized in a 3:1 ratio to undergo either both an early (day 2 to 4) dipyridamole (99m)Tc-sestamibi MPI study and a predischarge (day 6 to 12) submaximal exercise (99m)Tc-sestamibi MPI study or only the predischarge study. Multivariate predictors of in-hospital cardiac events included nuclear imaging summed stress and summed reversibility scores and peak creatine kinase. For postdischarge cardiac events, multivariate predictors in patients undergoing dipyridamole MPI included only the summed stress, reversibility, and rest imaging scores and anterior MI. For a given summed stress score, the interaction of reversibility score further improved the predictive value. Dipyridamole MPI showed better risk stratification than submaximal exercise MPI.

CONCLUSIONS

Dipyridamole MPI very early after MI predicts early and late cardiac events, with superior prognostic value compared with submaximal exercise imaging. The extent and severity of the stress defect and reversibility of the defect were the most important predictors of cardiac death and recurrent MI. This technique can allow management decisions to be made earlier with regard to AMI patients and could have important economic impact if applied widely.

Cost analysis of diagnostic testing for coronary artery disease in women with stable chest pain. Economics of Noninvasive Diagnosis (END) Study Group

BACKGROUND

Seven clinical sites compiled data from 4638 women who were referred directly to coronary angiography (catheterization-first strategy; n = 3375) or who underwent stress myocardial perfusion imaging (MPI) first (n = 1263) followed by coronary angiography if at least one reversible myocardial perfusion abnormality was detected. The study examines the cost minimization potential of these available invasive and noninvasive diagnostic strategies in women with chest pain.

METHODS AND RESULTS

Women in both groups were subclassified by the core laboratory as being at low (<0.15), intermediate (0.15 to 0.60), or high (>0.60) pretest likelihood for coronary artery disease (CAD). Among the catheterization-first patients, at least one coronary stenosis >70% was present in 13% of low likelihood patients, 29% of intermediate likelihood patients, and 52% of patients with high CAD likelihood. Perfusion abnormality rates in the MPI-first group were 23% in low likelihood patients, 27% in intermediate likelihood patients, and 34% in high CAD likelihood patients. Of the MPI-first subset, 50%, 55%, and 76%, respectively, underwent catheterization in at least one coronary stenosis >70%. Cardiac death rates ranged from 0.5% to 2.2% in patients with CAD and did not differ from the 2 testing strategies (P = not significant). The composite cost per patient of diagnostic testing plus follow-up medical care over a period of 2.5 +/- 1.5 years (calculated for both strategies from inflation-corrected Medicare charges, adjusted for institutional cost-charge ratios) ranged from $2490 for patients with low likelihood to $3687 for patients with high likelihood with the catheterization-first strategy and from $1587 to $2585 for patients undergoing MPI first (P < .01 between risk subsets and strategies).

CONCLUSIONS

In women referred for diagnostic evaluation of stable chest pain, MPI followed by selective coronary angiography in patients with at least 1 perfusion abnormality minimizes the near-term composite cost per patient compared with a direct catheterization-first strategy, regardless of pretest CAD likelihood.