Gender differences in the diagnostic accuracy of SPECT myocardial perfusion imaging: a bivariate meta-analysis

Impact of cardiac size on diagnostic performance of single-photon emission computed tomography myocardial perfusion imaging: insights from the REgistry of Fast Myocardial Perfusion Imaging with NExt generation single-photon emission computed tomography

AIMS

Variation in diagnostic performance of single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) has been observed, yet the impact of cardiac size has not been well characterized. We assessed whether low left ventricular volume influences SPECT MPI's ability to detect obstructive coronary artery disease (CAD) and its interaction with age and sex.

METHODS AND RESULTS

A total of 2066 patients without known CAD (67% male, 64.7 ± 11.2 years) across nine institutions underwent SPECT MPI with solid-state scanners followed by coronary angiography as part of the REgistry of Fast Myocardial Perfusion Imaging with NExt Generation SPECT. Area under receiver-operating characteristic curve (AUC) analyses evaluated the performance of quantitative and visual assessments according to cardiac size [end-diastolic volume (EDV); <20th vs. ≥20th population or sex-specific percentiles], age (<75 vs. ≥75 years), and sex. Significantly decreased performance was observed in patients with low EDV compared with those without (AUC: population 0.72 vs. 0.78, P = 0.03; sex-specific 0.72 vs. 0.79, P = 0.01) and elderly patients compared with younger patients (AUC 0.72 vs. 0.78, P = 0.03), whereas males and females demonstrated similar AUC (0.77 vs. 0.76, P = 0.67). The reduction in accuracy attributed to lower volumes was primarily observed in males (sex-specific threshold: EDV 0.69 vs. 0.79, P = 0.01). Accordingly, a significant decrease in AUC, sensitivity, specificity, and negative predictive value for quantitative and visual assessments was noted in patients with at least two characteristics of low EDV, elderly age, or male sex.

CONCLUSION

Detection of CAD with SPECT MPI is negatively impacted by small cardiac size, most notably in elderly and male patients.

Role of non-invasive coronary imaging in stable angina

Chest pain represents a symptom of significant clinical concern due to the potential for lethal etiologies. Accordingly, it is critical to ascertain the presence of stable angina through various diagnostic tests to inform subsequent therapeutic strategies. Stable angina, while potentially progressing to more severe conditions if left untreated, suffers from a paucity of research regarding its management compared to other more fatal causes of chest pain. Recent advancements in radiological imaging necessitate a re-evaluation of the array and functionality of diagnostic tests, with particular emphasis on prioritizing non-invasive methods such as electrocardiography and echocardiography. This study undertakes a comprehensive review of the literature pertaining to various diagnostic tests for stable angina. We conclude that the management of a patient presenting with chest pain encompasses a continuum of care, beginning with a detailed patient history to estimate pre-test probability and culminating in computed tomography coronary angiography. This continuum is highly individualized, taking into account patient-specific variables, disease burden, and test indications. In an era of rapid research advancement, our findings delineate the optimal sequence of initial diagnostic tests, emphasizing the role of current non-invasive imaging modalities as outlined in standard clinical guidelines.

Flurpiridaz F-18 PET Myocardial Perfusion Imaging in Patients With Suspected Coronary Artery Disease

BACKGROUND

Flurpiridaz F-18 (flurpiridaz) is a novel positron emission tomography (PET) myocardial perfusion imaging tracer.

OBJECTIVES

The purpose of this study was to further assess the diagnostic efficacy and safety of flurpiridaz for the detection and evaluation of coronary artery disease (CAD) defined as ≥50% stenosis by quantitative invasive coronary angiography (ICA).

METHODS

In this second phase 3 prospective multicenter clinical study, 730 patients with suspected CAD from 48 clinical sites in the United States, Canada, and Europe were enrolled. Patients underwent 1-day rest/stress flurpiridaz PET and 1- or 2-day rest-stress Tc-99m-labeled single photon emission computed tomography (SPECT) before ICA. PET and SPECT images were read by 3 experts blinded to clinical and ICA data.

RESULTS

A total of 578 patients (age 63.7 ± 9.5 years) were evaluable; 32.5% were women, 52.3% had body mass index ≥30 kg/m2, and 33.6% had diabetes. Flurpiridaz PET met the efficacy endpoints of the study; its sensitivity and specificity were significantly higher than the prespecified threshold value by 2 of the 3 readers. The sensitivity of flurpiridaz PET was higher than SPECT (80.3% vs 68.7%; P = 0.0003) and its specificity was noninferior to SPECT (63.8% vs 61.7%; P = 0.0004). PET area under the receiver-operating characteristic curves were higher than SPECT in the overall population (0.80 vs 0.68; P < 0.001), women, and obese patients (P < 0.001 for both). Flurpiridaz PET was superior to SPECT (P < 0.001) for perfusion defect size/severity evaluation, image quality, diagnostic certainty, and radiation exposure. Flurpiridaz PET was safe and well tolerated.

CONCLUSIONS

This second flurpiridaz PET myocardial perfusion imaging trial shows that flurpiridaz has utility as a new tracer for CAD detection, specifically in women and obese patients. (An International Study to Evaluate Diagnostic Efficacy of Flurpiridaz [18F] Injection PET MPI in the Detection of Coronary Artery Disease [CAD]; NCT03354273).

Approach to Imaging Ischemia in Women

Approach to imaging ischemia in women Coronary artery disease in women tends to have a worse short- and long-term prognosis relative to men and remains the leading cause of mortality worldwide. Both clinical symptoms and diagnostic approach remain challenging in women due to lesser likelihood of women presenting with classic anginal symptoms on one hand and underperformance of conventional exercise treadmill testing in women on the other. Moreover, a higher proportion of women with signs and symptoms suggestive of ischemia are more likely to have nonobstructive coronary artery disease (CAD) that requires additional imaging and therapeutic considerations. New imaging techniques such as coronary computed tomography (CT) angiography, CT myocardial perfusion imaging, CT functional flow reserve assessment, and cardiac magnetic resonance imaging carry substantially better sensitivity and specificity for the detection of ischemia and coronary artery disease in women. Familiarity with various clinical subtypes of ischemic heart disease in women and with the major advantages and disadvantages of advanced imaging tests to ensure the decision to select one modality over another is one of the keys to successful diagnosis of CAD in women. This review compares the 2 major types of ischemic heart disease in women - obstructive and nonobstructive, while focusing on sex-specific elements of its pathophysiology.

Mitigating bias in deep learning for diagnosis of coronary artery disease from myocardial perfusion SPECT images

PURPOSE

Artificial intelligence (AI) has high diagnostic accuracy for coronary artery disease (CAD) from myocardial perfusion imaging (MPI). However, when trained using high-risk populations (such as patients with correlating invasive testing), the disease probability can be overestimated due to selection bias. We evaluated different strategies for training AI models to improve the calibration (accurate estimate of disease probability), using external testing.

METHODS

Deep learning was trained using 828 patients from 3 sites, with MPI and invasive angiography within 6 months. Perfusion was assessed using upright (U-TPD) and supine total perfusion deficit (S-TPD). AI training without data augmentation (model 1) was compared to training with augmentation (increased sampling) of patients without obstructive CAD (model 2), and patients without CAD and TPD < 2% (model 3). All models were tested in an external population of patients with invasive angiography within 6 months (n = 332) or low likelihood of CAD (n = 179).

RESULTS

Model 3 achieved the best calibration (Brier score 0.104 vs 0.121, p < 0.01). Improvement in calibration was particularly evident in women (Brier score 0.084 vs 0.124, p < 0.01). In external testing (n = 511), the area under the receiver operating characteristic curve (AUC) was higher for model 3 (0.930), compared to U-TPD (AUC 0.897) and S-TPD (AUC 0.900, p < 0.01 for both).

CONCLUSION

Training AI models with augmentation of low-risk patients can improve calibration of AI models developed to identify patients with CAD, allowing more accurate assignment of disease probability. This is particularly important in lower-risk populations and in women, where overestimation of disease probability could significantly influence down-stream patient management.

Sex-specific associations of myocardial perfusion imaging with outcomes in patients with suspected chronic coronary syndrome

BACKGROUND

Myocardial perfusion scintigraphy (MPS) is an established diagnostic technique for inducible ischemia in patients with suspected chronic coronary syndrome (CCS). Some MPS findings, most notably an ischemia extent>10% of the left ventricle (LV), hold prognostic significance and support maximization of anti-ischemic treatment. We aimed to assess sex-specific associations of MPS findings with cardiovascular (CV) events in a population at high risk of CCS.

METHODS

In a prospective cohort study, 1,229 consecutive patients (age 70 ± 9.5 years, 73.5% males) without known CCS were referred to stress-rest MPS. All patients were followed for a median of 4.6 years for CV events.

RESULTS

Men and women had comparable risk profiles and incidence rates of CV events (6.6% vs. 4.6% respectively, P = 0.186). A summed stress score (SSS) > 7 was associated with the primary endpoint, including CV death and/or nonfatal myocardial infarction (MI) (adjusted hazard ratio [HR], 3.13; 95% confidence interval [CI], 1.79-5.46; P = 0.001), all-cause mortality (HR, 3.01; 95% CI, 1.31-6.93; P = 0.01), and incidence of late revascularization (HR, 1.84; 95% CI, 1.22-2.78; P = 0.004) in men but not women. A summed difference score (SDS) > 6 was related to a higher rate of the primary endpoint only in men (adjusted HR, 1.97; 95% CI, 1.18-3.30; P = 0.009).

CONCLUSIONS

Among patients undergoing a diagnostic workup for suspected CCS, stress perfusion and reversible ischemia abnormalities may independently predict worse survival and more CV events in men. However, the obtained results indicated the need for sex-specific cutoffs to refine risk stratification and assist in clinical decisions on anti-ischemic therapy beyond coronary artery anatomy.

Multimodality Imaging in the Detection of Ischemic Heart Disease in Women

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

Imaging of heart disease in women: review and case presentation

Cardiovascular diseases (CVD) remain the leading cause of mortality worldwide. Although major diagnostic and therapeutic advances have significantly improved the prognosis of patients with CVD in the past decades, these advances have less benefited women than age-matched men. Noninvasive cardiac imaging plays a key role in the diagnosis of CVD. Despite shared imaging features and strategies between both sexes, there are critical sex disparities that warrant careful consideration, related to the selection of the most suited imaging techniques, to technical limitations, and to specific diseases that are overrepresented in the female population. Taking these sex disparities into consideration holds promise to improve management and alleviate the burden of CVD in women. In this review, we summarize the specific features of cardiac imaging in four of the most common presentations of CVD in the female population including coronary artery disease, heart failure, pregnancy complications, and heart disease in oncology, thereby highlighting contemporary strengths and limitations. We further propose diagnostic algorithms tailored to women that might help in selecting the most appropriate imaging modality.

Body Mass Index Is Independently Associated with the Presence of Ischemia in Myocardial Perfusion Imaging

Background and Objectives: Obesity has been linked to various cardiovascular risk factors, increased incidence of coronary artery disease, and myocardial perfusion defects. The aim of this study was to investigate if body mass index (BMI) and waist circumference (WC) were associated with myocardial perfusion defects. Materials and Methods: A total of 308 consecutive patients who had myocardial perfusion imaging (MPI) with single photon emission computed tomography (SPECT) and a complete medical record on file were studied retrospectively. Results: The median age was 69 (61−76) years, the BMI was 27.6 (24.4−30.7) kg/m2, and the WC was 110 (102−118) cm. Of the 308 patients, 239 patients (77.6%) had myocardial ischemia. A positive test for ischemia was more frequent in men compared to women (72 vs. 28%, p < 0.001). Within the male group, BMI and WC were not significantly different between the ischemia and non-ischemia groups. In contrast, within the female group, both BMI (30.2 vs. 27.1 kg/m2, p = 0.002) and WC (112 vs. 105.5 cm, p = 0.020) were significantly higher in the ischemia group. Multivariable logistic regression showed that male sex and BMI were the only two independent predictors of ischemia in our patient population. Conclusions: This study showed that BMI was an independent predictor of ischemia in our patient population.

The additive prognostic value of coronary calcium score (CCS) to single photon emission computed tomography myocardial perfusion imaging (SPECT-MPI)-real world data from a single center

AIMS

Single-photon emission computed tomography myocardial perfusion imaging [SPECT-MPI] is a functional test for coronary ischemia. We aimed to assess the additive prognostic value of coronary calcium score (CCS) to SPECT-MPI in stable patients.

METHODS

This study is a retrospective analysis of 655 patients who underwent SPECT-MPI with CCS (2012 to 2017). Receiver operator characteristic (ROC) identified CCS cutoff value for all-cause mortality: CCS+ if > cutoff value and MPI+ if ≥ 5% total perfusion defect (TPD). Patients were divided into 1 MPI-/CCS-; 2 MPI+/CCS-; 3 MPI-/CCS+; 4 MPI+/CCS+ and compared. Cox proportional hazard analysis identified predictors of mortality.

RESULTS

CCS cutoff for all-cause mortality was > 216 (C statistic 0.756, P < 0.0001). In MPI+ groups, mean TPD was similar (13.4% and 13.1% respectively) but mortality was higher in the CCS+ (12.5% vs. 4.8%, P = 0.22) as was the severe LV systolic dysfunction (8.0% vs. 0%, P = 0.095). In MPI- groups, mean TPD was similar (0.7% and 0.9% respectively) but all-cause mortality was higher in the CCS+ (10.7% vs. 1.6%, P < 0.0001) as was severe LVSD (2.9 % vs. 0.3% P = 0.016). Age, smoking, renal impairment ,and CCS > 216 were independent predictors of mortality.

CONCLUSIONS

Patients with raised CCS on SPECT-MPI have increased mortality and poor LV function despite a negative MPI.

Effects of gender and defect reversibility on detection of coronary disease with an upright and supine cadmium-zinc-telluride camera

BACKGROUND

Limited data address the roles of gender, perfusion defect reversibility, and imaging position in interpretation of images acquired on an upright/supine cadmium-zinc-telluride (CZT) cardiac imaging system.

METHODS AND RESULTS

From a consecutive cohort of patients imaged on an upright/supine CZT camera, 260 patients with coronary angiograms were studied. Multivariable models identified gender as a significant effect modifier for imaging variables of CAD. For males, a supine summed stress score (SSS) ≥ 3 provided high accuracy (sensitivity 70.7%, specificity 72.2%), and highest contribution to multivariable models. In females, supine SSS ≥ 2 provided the best cut-off for defect size and severity (sensitivity 90%, specificity 35.9%), but specificity was improved substantially to 53.3% with decrease in sensitivity to 80% by also requiring quantitative identification of perfusion defect reversibility in the supine position. Eight variables, accurate for predicting coronary disease, were more accurate with supine than upright imaging.

CONCLUSIONS

Perfusion defect reversibility improved specificity in female patients for detection of coronary disease compared to perfusion defect size and extent alone. Supine images provided superior accuracy for detection of coronary disease compared to upright images.

Vitamin D Deficiency as a Risk Factor for Myocardial Ischemia

Background and Objectives: Vitamin D (Vit D) deficiency has been implicated in various conditions, including cardiovascular disease. The purpose of this retrospective study was to investigate the incidence of patients with myocardial ischemia in relation to their serum levels of vitamin D. Materials and Methods: A 64-month search (January 2016 to April 2021) in our database of the Nuclear Medicine Laboratory revealed 113 patients who had both myocardial perfusion imaging with single photon emission computed tomography (MPI SPECT) and Vit D measurements. MPI SPECT obtained myocardial images during both stress (summed stress score, SSS) and rest (summed rest score, SRS). Abnormal MPI SPECT was when the SSS was ≥4. Vit D was determined by radioimmunoassay (RIA). Patients with Vit D values <10 ng/mL, 10-29 ng/mL and ≥30 ng/mL were defined as having a deficiency, insufficiency and sufficiency, respectively. Results: Among patients, 46/113 (40.7%) were male and 67/113 (59.3%) were female. Abnormal MPI was found in 58/113 (51.3%) patients. Vit D deficiency was noted in 20/113 (17.7%) patients, insufficiency in 86/113 (76.1%) patients, and normal Vit D was noted in only 7/113 (6.2%) patients. Sixteen of the 20 patients (80%) with Vit D deficiency, and 38/86 (44.2%) with insufficiency had an abnormal MPI SPECT. In contrast, only 1/7 (14.3%) patients with sufficient Vit D levels had an abnormal MPI SPECT. The Mann-Whitney U-test showed that ischemia reduced the values of Vit D. Correlation analysis showed a negative association of Vit D levels with SSS (rho = -0.232, p = 0.014) and SRS (rho = -0.250, p = 0.008). Further evaluation with a Vit D cut off 20 ng/mL retrieved no statistical significance. Finally, Vit D and gender were independently associated with myocardial ischemia. Conclusions: Low Vit D levels may represent a risk factor for myocardial ischemia.

State of the Art in Noninvasive Imaging of Ischemic Heart Disease and Coronary Microvascular Dysfunction in Women: Indications, Performance, and Limitations

PURPOSE OF REVIEW

Establishing a diagnosis of ischemic heart disease (IHD) in women, including assessment for coronary microvascular dysfunction (CMD) when indicated, can be challenging. Access to performance of invasive testing when appropriate may be limited, and noninvasive imaging assessments have evolved. This review will summarize the various noninvasive imaging modalities available for the diagnosis of IHD and CMD in women, outlining indications, performance modalities, advantages, and limitations.

RECENT FINDINGS

While stress echocardiography and single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) are widely available and can detect IHD in women, their ability to specifically identify CMD is limited. Novel developments in cardiac magnetic resonance (CMR) imaging, including spectroscopy, and positron emission tomography (PET) have changed the diagnostic landscape. Coronary computed tomographic angiography (CCTA), while unable to diagnose CMD, is developing an emerging role in the risk stratification of ischemic syndromes. Despite the discovery of increased CMD prevalence in symptomatic women and technological advances in diagnostic imaging, practitioners are limited by user expertise and center availability when choosing a diagnostic imaging modality. Knowledge of this evolving field is imperative as it highlights the need for sex-specific assessment of cardiovascular syndromes.

The role of imaging in women with ischemic heart disease

Substantial advances and insights in medical technology and treatment strategies, and the focus on sex-specific research have contributed to a reduction in cardiovascular mortality in women. Despite these advances, ischemic heart disease (IHD) remains the leading cause of cardiovascular morbidity and mortality of women in the Western world. Advances in cardiovascular imaging, over the past 4 decades, have significantly improved the evaluation and management of the full spectrum of coronary atherosclerosis, which contributes to ischemic heart disease. The development of contemporary and novel diagnostic imaging techniques and tools have assumed an expanded role in the evaluation of symptomatic women to detect not only flow-limiting epicardial coronary stenosis and nonobstructive atherosclerosis, but also ischemia resulting from microvascular dysfunction. IHD is now diagnosed early and with greater accuracy, leading to improved risk assessment and timely therapies in women. In this article, we review the available evidence on the role of contemporary diagnostic imaging techniques in the evaluation of women with suspected IHD.

Diagnostic accuracy of stress myocardial perfusion imaging in Indian diabetic patients: A single centre experience

Diabetics have around 2-4 times increased risk of coronary artery disease(CAD) and it is the most important cause of mortality in these patients. This study was carried out to compare the sensitivity, specificity and accuracy of MPI-SPECT among diabetics and non-diabetics in the Indian population.

Material and Methods:

This retrospective study included 261 patients; 213 males and 48 females, with 75 diabetic and 186 non-diabetic patients. Only type II diabetics and non-diabetic patients were included in the study. Only patients who had coronary angiography (CAG) done within 6 months of the stress ^99mTc-sestamibi MPI-SPECT study were included in the study. Two arbitrary cut off points on CAG ≥ 50% and ≥ 70% were used for determination of extent of CAD.

Results:

Considering coronary angiography as gold standard with ≥ 50% coronary stenosis as a cut off criteria for significant stenosis the sensitivity and specificity respectively, of myocardial perfusion SPECT was 83% and 72% in diabetics and 81% and 69% in non-diabetic pateints (p value not significant). For ≥ 70% coronary stenosis as a cut off criteria for significant stenosis the sensitivity and specificity respectively, of myocardial perfusion SPECT was 87% and 61% in diabetics and 88% and 58%in non-diabetics (p value not significant). No significant difference was found in the sensitivity, specificity and accuracy of LAD, LCx and RCA coronary vessels among diabetics and non-diabetics for both ≥ 50% and ≥ 70% coronary stenosis as cut off criteria. Diabetic patients had a lower incidence of SVD compared to the non-diabetic patients. They also had a higher incidence of TVD and MVD compared to the non-diabetic patients with both ≥ 50% and ≥ 70% diameter stenosis criteria (p value significant).

Conclusion:

Sensitivity and specificity of ^99mTc-sestamibi myocardial perfusion imaging is similar in diabetic and non-diabetic patients in Indian population.

Computed Tomographic Perfusion Improves Diagnostic Power of Coronary Computed Tomographic Angiography in Women

Background—

Coronary computed tomographic angiography (CTA) and myocardial perfusion imaging (CTP) is a validated approach for detection and exclusion of flow-limiting coronary artery disease (CAD), but little data are available on gender-specific performance of these modalities. In this study, we aimed to evaluate the diagnostic accuracy of combined coronary CTA and CTP in detecting flow-limiting CAD in women compared with men.

Methods and Results—

Three hundred and eighty-one patients who underwent both CTA-CTP and single-photon emission computed tomography myocardial perfusion imaging preceding invasive coronary angiography as part of the CORE320 multicenter study (Coronary Artery Evaluation Using 320-row Multidetector Computed Tomography Angiography and Myocardial Perfusion) were included in this ancillary study. All 4 image modalities were analyzed in blinded, independent core laboratories. Prevalence of flow-limiting CAD defined by invasive coronary angiography equal to 50% or greater with an associated single-photon emission computed tomography myocardial perfusion imaging defect was 45% (114/252) and 23% (30/129) in males and females, respectively. Patient-based diagnostic accuracy defined by the area under the receiver operating curve for detecting flow-limiting CAD by CTA alone in females was 0.83 (0.75–0.89) and for CTA-CTP was 0.92 (0.86–0.97; P =0.003) compared with men where the area under the receiver operating curve for detecting flow-limiting CAD by CTA alone was 0.82 (0.77–0.87) and for CTA-CTP was 0.84 (0.80–0.89; P =0.29).

Conclusions—

The combination of CTA-CTP was performed similarly in men and women for identifying flow-limiting coronary stenosis; however, in women, CTP had incremental value over CTA alone, which was not the case in men.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT00934037.

The role of pharmacological stress testing in women

Pharmacological stress is an alternative method to dynamic exercise that combined with noninvasive imaging allows the detection of flow-limiting coronary artery disease (CAD). It represents the stress procedure of choice in patients who cannot exercise appropriately. In women, pharmacological stress combined with myocardial perfusion scintigraphy (MPS) has demonstrated to be highly accurate for the detection of obstructive CAD and a valuable tool that helps separate patients at low cardiac risk from those with an adverse prognosis. Pharmacological stress with positron emission tomographic (PET) imaging is increasingly used in the investigation of suspected obstructive CAD; available evidence shows that the diagnostic profile and prognostic value of stress PET imaging is similar to that of stress MPS in women.

Danish study of Non-Invasive testing in Coronary Artery Disease (Dan-NICAD): study protocol for a randomised controlled trial

BACKGROUND

Coronary computed tomography angiography (CCTA) is an established method for ruling out coronary artery disease (CAD). Most patients referred for CCTA do not have CAD and only approximately 20-30 % of patients are subsequently referred to further testing by invasive coronary angiography (ICA) or non-invasive perfusion evaluation due to suspected obstructive CAD. In cases with severe calcifications, a discrepancy between CCTA and ICA often occurs, leading to the well-described, low-diagnostic specificity of CCTA. As ICA is cost consuming and involves a risk of complications, an optimized algorithm would be valuable and could decrease the number of ICAs that do not lead to revascularization. The primary objective of the Dan-NICAD study is to determine the diagnostic accuracy of cardiac magnetic resonance imaging (CMRI) and myocardial perfusion scintigraphy (MPS) as secondary tests after a primary CCTA where CAD could not be ruled out. The secondary objective includes an evaluation of the diagnostic precision of an acoustic technology that analyses the sound of coronary blood flow. It may potentially provide better stratification prior to CCTA than clinical risk stratification scores alone.

METHODS/DESIGN

Dan-NICAD is a multi-centre, randomised, cross-sectional trial, which will include approximately 2,000 patients without known CAD, who were referred to CCTA due to a history of symptoms suggestive of CAD and a low-risk to intermediate-risk profile, as evaluated by a cardiologist. Patient interview, sound recordings, and blood samples are obtained in connection with the CCTA. All patients with suspected obstructive CAD by CCTA are randomised to either stress CMRI or stress MPS, followed by ICA with fractional flow reserve (FFR) measurements. Obstructive CAD is defined as an FFR below 0.80 or as high-grade stenosis (>90 % diameter stenosis) by visual assessment. Diagnostic performance is evaluated as sensitivity, specificity, predictive values, likelihood ratios, and C statistics. Enrolment commenced in September 2014 and is expected to be complete in May 2016.

DISCUSSION

Dan-NICAD is designed to assess whether a secondary perfusion examination after CCTA could safely reduce the number of ICAs where revascularization is not required. The results are expected to add knowledge about the optimal algorithm for diagnosing CAD.

TRIAL REGISTRATION

Clinicaltrials.gov identifier, NCT02264717 . Registered on 26 September 2014.

Multi-modality Imaging: Bird's eye view from the 2015 American Heart Association Scientific Sessions

Multiple novel studies were presented at the 2015 American Heart Association Scientific Sessions which was considered a successful conference at many levels. In this review, we will summarize key studies in nuclear cardiology, cardiac magnetic resonance, echocardiography, and cardiac computed tomography that were presented at the Sessions. We hope that this bird's eye view will keep readers updated on the newest imaging studies presented at the meeting whether or not they were able to attend the meeting.

Women-specific factors to consider in risk, diagnosis and treatment of cardiovascular disease

In the era of individualized medicine, gaps in knowledge remain about sex-specific risk factors, diagnostic and treatment options that might reduce mortality from cardiovascular disease (CVD) and improve outcomes for both women and men. In this review, contributions of biological mechanisms involving the sex chromosomes and the sex hormones on the cardiovascular system will be discussed in relationship to the female-specific risk factors for CVD: hypertensive disorders of pregnancy, menopause and use of hormonal therapies for contraception and menopausal symptoms. Additionally, sex-specific factors to consider in the differential diagnosis and treatment of four prevalent CVDs (hypertension, stroke, coronary artery disease and congestive heart failure) will be reviewed with emphasis on areas where additional research is needed.

Comparison of cardiovascular magnetic resonance and single-photon emission computed tomography in women with suspected coronary artery disease from the Clinical Evaluation of Magnetic Resonance Imaging in Coronary Heart Disease (CE-MARC) Trial

BACKGROUND

Coronary artery disease is the leading cause of death in women, and underdiagnosis contributes to the high mortality. This study compared the sex-specific diagnostic performance of cardiovascular magnetic resonance (CMR) and single-photon emission computed tomography (SPECT).

METHODS AND RESULTS

A total of 235 women and 393 men with suspected angina underwent CMR, SPECT, and x-ray angiography as part of the Clinical Evaluation of Magnetic Resonance Imaging in Coronary Heart Disease (CE-MARC) study. CMR comprised adenosine stress/rest perfusion, cine imaging, late gadolinium enhancement, and magnetic resonance coronary angiography. Gated adenosine stress/rest SPECT was performed with (99m)Tc-tetrofosmin. For CMR, the sensitivity in women and men was similar (88.7% versus 85.6%; P=0.57), as was the specificity (83.5% versus 82.8%; P=0.86). For SPECT, the sensitivity was significantly worse in women than in men (50.9% versus 70.8%; P=0.007), but the specificities were similar (84.1% versus 81.3%; P=0.48). The sensitivity in both the female and male groups was significantly higher with CMR than SPECT (P<0.0001 for both), but the specificity was similar (P=0.77 and P=1.00, respectively). For perfusion-only components, CMR outperformed SPECT in women (area under the curve, 0.90 versus 0.67; P<0.0001) and in men (area under the curve, 0.89 versus 0.74; P<0.0001). Diagnostic accuracy was similar in both sexes with perfusion CMR (P=1.00) but was significantly worse in women with SPECT (P<0.0001).

CONCLUSIONS

In both sexes, CMR has greater sensitivity than SPECT. Unlike SPECT, there are no significant sex differences in the diagnostic performance of CMR. These findings, plus an absence of ionizing radiation exposure, mean that CMR should be more widely adopted in women with suspected coronary artery disease.

CLINICAL TRIAL REGISTRATION URL

http://www.controlled-trials.com. Unique identifier: ISRCTN77246133.

Gender differences in the evaluation of coronary artery disease with a cadmium-zinc telluride camera

PURPOSE

Coronary artery disease remains one of the most significant causes of morbidity and mortality among women. The published literature shows the importance of standard single photon emission computed tomography in the evaluation of women with known or suspected ischaemic heart disease, in terms of target intervention and clinical treatment. The purpose of the present study was to ascertain the diagnostic accuracy of cadmium-zinc-telluride (CZT) myocardial perfusion imaging according to gender, within a prospective database of patients with known or suspected coronary artery disease, using coronary angiography as the reference standard.

METHODS

Included in the study were 309 consecutive patients, of whom 248 were men (80 %), with known or suspected coronary artery disease and who had been referred to our laboratory for stress-rest myocardial perfusion imaging. All patients underwent coronary angiography within 30 days. All patients underwent a single-day stress-rest low-dose ultrafast protocol. Fifteen minutes after the end of the stress (dose range 185 to 222 MBq of (99m)Tc-tetrofosmin), all patients underwent the first scan with an acquisition time of 7 min. The rest scan (dose range 370 to 444 MBq of (99m)Tc-tetrofosmin) was acquired from 30 min to 45 min after injection, with an acquisition time of 6 min. Images were visually inspected, and summed stress scores (SSS) and summed rest scores (SRS) were obtained.

RESULTS

Image quality was graded "good" or better in more than 90 % of patients. On coronary angiography, left main trunk stenosis, left anterior descending artery stenosis, left circumflex artery stenosis and right coronary artery stenosis were seen in 3, 155 , 142 and 131 patients, respectively. In women, the mean SSS and SRS were 8 ± 5 and 3 ± 1, respectively. Semiquantitative regional and global SSS were good discriminants of coronary artery disease, and the overall area under the receiver operator characteristic (ROC) curve was 0.822 (95 % CI 0.685 - 0.959). The value was comparable to that obtained in men (overall ROC area 0.884, 95 % CI 0.836 - 0.933).

CONCLUSION

A low-dose protocol with a CZT camera can be routinely used in women with known or suspected coronary artery disease without loss of accuracy and with lower radiation exposure of the patients.

Incremental value of objective cardiac testing in addition to physician impression and serial contemporary troponin measurements in women

OBJECTIVES

Guidelines recommend that patients presenting to the emergency department (ED) with chest pain who are at low risk for acute coronary syndrome (ACS) receive an objective cardiac evaluation with a stress test or coronary imaging. It is uncertain whether all women derive benefit from this process. The study aim was to determine the incremental value of objective cardiac testing after serial cardiac markers and physician risk assessment.

METHODS

Women enrolled in the 18-site Myeloperoxidase in the Diagnosis of Acute Coronary Syndrome (MIDAS) study had serial troponin I measured at time 0 and 90 minutes and physician risk assessment for the presence of ACS. Risk estimates obtained at the time of ED evaluation were dichotomized as high or non-high risk. The primary outcome was the composite of acute myocardial infarction (AMI) or revascularization at 30 days. Logistic regression with receiver operator characteristic (ROC) curves and net reclassification index were used to determine the diagnostic accuracy for the composite outcome of 30-day MI or revascularization for two models: 1) troponin I results and physician risk assessment alone and 2) troponin I results, physician risk assessment, and objective cardiac testing.

RESULTS

A total of 460 women with a median age 58 years (interquartile range [IQR] = 48.5 to 68 years) were included, and 32 (6.9%) experienced AMI or revascularization by 30 days. Comparison of the area under the ROC curves (AUC) showed that the addition of objective cardiac testing to the combination of troponin I results and physician risk assessment did not significantly improve prediction of 30-day AMI or revascularization (AUC = 0.85 vs. 0.89; p = .053). Using a threshold of 1%, net reclassification index showed that the addition of objective cardiac testing to troponin I results and physician risk assessment worsened the prediction for 30-day AMI and revascularization. All of the reclassified patients were false positives, with nine (2.1%) patients incorrectly reclassified from <1% risk to ≥ 1% risk of 30-day AMI or revascularization.

CONCLUSIONS

In the era of contemporary troponin assays, objective cardiac testing after an ED clinician risk assessment of non-high risk and negative troponin I results at 0 and 90 minutes does not improve the prediction of 30-day AMI or revascularization in women presenting with chest pain or other symptoms of cardiac ischemia.