Angiographic correlations of patients with small vessel disease diagnosed by adenosine-stress cardiac magnetic resonance imaging

Myocardial Perfusion Imaging by Cardiovascular Magnetic Resonance: Research Progress and Current Implementation

Cardiovascular diseases pose a significant health and economic burden worldwide, with coronary artery disease still recognized as a major problem. It is closely associated with hypertension, diabetes, obesity, smoking, lack of exercise, poor diet, and excessive alcohol consumption, which may lead to macro- and microvascular abnormalities in the heart. Coronary artery stenosis reduces the local supply of oxygen and nutrients to the myocardium and results in reduced levels of myocardial perfusion, which can lead to more severe conditions and irreversible damage to myocardial tissues. Therefore, accurate evaluation of myocardial perfusion abnormalities in patients with these risk factors is critical. As technology advances, magnetic resonance myocardial perfusion imaging has become more accurate at evaluating the myocardial microcirculation and has shown a powerful ability to detect myocardial ischemia. The purpose of this review is to summarize the principle, research progress of acquisition and analysis, and clinical implementation of cardiovascular magnetic resonance (CMR) myocardial perfusion imaging.

Cardiovascular magnetic resonance in women with cardiovascular disease: position statement from the Society for Cardiovascular Magnetic Resonance (SCMR)

This document is a position statement from the Society for Cardiovascular Magnetic Resonance (SCMR) on recommendations for clinical utilization of cardiovascular magnetic resonance (CMR) in women with cardiovascular disease. The document was prepared by the SCMR Consensus Group on CMR Imaging for Female Patients with Cardiovascular Disease and endorsed by the SCMR Publications Committee and SCMR Executive Committee. The goals of this document are to (1) guide the informed selection of cardiovascular imaging methods, (2) inform clinical decision-making, (3) educate stakeholders on the advantages of CMR in specific clinical scenarios, and (4) empower patients with clinical evidence to participate in their clinical care. The statements of clinical utility presented in the current document pertain to the following clinical scenarios: acute coronary syndrome, stable ischemic heart disease, peripartum cardiomyopathy, cancer therapy-related cardiac dysfunction, aortic syndrome and congenital heart disease in pregnancy, bicuspid aortic valve and aortopathies, systemic rheumatic diseases and collagen vascular disorders, and cardiomyopathy-causing mutations. The authors cite published evidence when available and provide expert consensus otherwise. Most of the evidence available pertains to translational studies involving subjects of both sexes. However, the authors have prioritized review of data obtained from female patients, and direct comparison of CMR between women and men. This position statement does not consider CMR accessibility or availability of local expertise, but instead highlights the optimal utilization of CMR in women with known or suspected cardiovascular disease. Finally, the ultimate goal of this position statement is to improve the health of female patients with cardiovascular disease by providing specific recommendations on the use of CMR.

Alterations in heart rate variability are associated with abnormal myocardial perfusion

BACKGROUND

Abnormalities in the autonomic nervous system may occur in ischemic heart disease, but the mechanisms by which they are linked are not fully defined. The risk of cardiac events is increased during morning hours. Studying the contributions of autonomic mechanisms may yield insights into risk stratification and treatment. We hypothesize that autonomic dysfunction, measured by decreased heart rate variability (HRV), associates with abnormal stress myocardial perfusion imaging (MPI).

METHODS

We performed a cross-sectional study of the association between abnormal myocardial stress perfusion with HRV using 276 middle-aged veteran twins without known ischemic heart disease. The primary independent variable was cardiac autonomic regulation measured with 24-hour electrocardiogram (ECG) monitoring, using linear and non-linear (multipole density, or Dyx) HRV metrics. The primary outcome was abnormal perfusion (>5% affected myocardium) during adenosine stress on [13N]-ammonia myocardial perfusion imaging with positron emission tomography.

RESULTS

The mean (SD) age was 53 (3) years and 55 (20%) had abnormal perfusion. HRV (by Dyx) was reduced during morning hours in subjects with abnormal perfusion. At 7 AM, each standard deviation (SD) decrease in Dyx was associated a 4.8 (95% CI, 1.5 - 15.8) odds ratio (OR) for abnormal MPI. With Dyx < 2.0, the 7 AM OR for abnormal MPI was 11.8 (95% CI, 1.2 - 111.4).

CONCLUSIONS

Autonomic dysfunction, measured by non-linear HRV in the morning hours, was associated with an increased OR of abnormal MPI. These results suggest a potentially important role of ECG-based biomarkers in risk stratification for individuals with suspected ischemic heart disease.

Standardized image interpretation and post-processing in cardiovascular magnetic resonance - 2020 update : Society for Cardiovascular Magnetic Resonance (SCMR): Board of Trustees Task Force on Standardized Post-Processing

With mounting data on its accuracy and prognostic value, cardiovascular magnetic resonance (CMR) is becoming an increasingly important diagnostic tool with growing utility in clinical routine. Given its versatility and wide range of quantitative parameters, however, agreement on specific standards for the interpretation and post-processing of CMR studies is required to ensure consistent quality and reproducibility of CMR reports. This document addresses this need by providing consensus recommendations developed by the Task Force for Post-Processing of the Society for Cardiovascular Magnetic Resonance (SCMR). The aim of the Task Force is to recommend requirements and standards for image interpretation and post-processing enabling qualitative and quantitative evaluation of CMR images. Furthermore, pitfalls of CMR image analysis are discussed where appropriate. It is an update of the original recommendations published 2013.

State-of-the-Art Quantitative Assessment of Myocardial Ischemia by Stress Perfusion Cardiac Magnetic Resonance

Ischemic heart disease remains the foremost determinant of death and disability across the world. Quantification of the ischemia burden is currently the preferred approach to predict event risk and to trigger adequate treatment. Cardiac magnetic resonance (CMR) can be a prime protagonist in this scenario due to its synergistic features. It allows assessment of wall motility, myocardial perfusion, and tissue scar by means of late gadolinium enhancement imaging. We discuss the clinical and preclinical aspects of gadolinium-based, perfusion CMR imaging, including the relevance of high spatial resolution and 3-dimensional whole-heart coverage, among important features of this auspicious method.

Advanced imaging techniques (CT and MR): Gender-based diagnostic work-up in ischemic heart disease?

It is ascertained that the epidemiology and social impact of ischemic heart disease is substantially different between the two genders. Moreover, there is substantial evidence that gender is able to modulate the clinical manifestation of most cardiac diseases, and specifically of coronary artery disease. Particularly, women present less angiographically significant coronary artery disease, smaller vessel lumen, and less plaque rupture occurrence as compared to men. On the contrary, manifestations as vasospasm, impaired vasodilatation at epicardial level, and microvascular dysfunction are more common in female. In clinical practice, it is important to know the gender-based aspects of clinical disease expression and how to diversify the diagnostic work-up. Cardiac Computed Tomography and Cardiac Magnetic Resonance are relatively new diagnostic imaging tools employed for studying both the cardiac structures and the pathophysiology of the cardiovascular system. In this paper, we aim to overview the non-invasive diagnostic role in a gender's dimension, mainly focusing on Cardiac Computed Tomography and Cardiac Magnetic Resonance in ischemic heart disease, and to understand whether the existing evidences support a different diagnostic work-up approach.

Microvascular retinopathy and angiographically-demonstrated coronary artery disease: A cross-sectional, observational study

Epidemiological studies suggest retinal microvascular abnormalities predict cardiac events. This study examined microvascular features associated with coronary artery abnormalities. This was a single-centre, cross-sectional, observational study of 144 consecutive subjects undergoing coronary angiography for clinical indications. Their angiograms were deidentified and graded for disease (Leaman score, LAD stenosis ≥ 70%, number of vessels stenosed ≥ 70%), and Thrombolysis in Myocardial Infarction (TIMI) blush score. Subjects also underwent retinal photography (KOWA non-mydriatic camera, Japan), and their deidentified retinal images were graded for hypertensive microvascular retinopathy (Wong and Mitchell classification), vessel calibre using a computer-assisted method (IVAN, U Wisconsin), and diabetic retinopathy (modified Airlie House scheme) independently by a trained grader and an ophthalmologist. Retinal abnormalities were compared between subjects with high and low angiography scores using one way ANOVA, Chi squared and logistic regression analysis (StataCorp, Texas). Subjects had a mean age of 61 years (range 32–88), and included 101 males (70%). Seventeen (12%) had Leaman scores > 10.5, 46 (32%) had LAD stenosis, 13 (9%) had ≥ 3 arteries stenosed, and 20 (14%) had TIMI blush scores < 1. Twenty-six subjects (18%) had a retinal hemorrhage, and 115 (74%) a mild or moderate hypertensive retinopathy. Fifty-five (38%) had diabetes, and 24 (17%) a background (n = 20) or proliferative (n = 4) diabetic retinopathy. A retinal hemorrhage (p = 0.046), moderate microvascular retinopathy (p = 0.08) and proliferative diabetic retinopathy (p = 0.04) were all associated with a higher Leaman score. Venular calibre was increased with triple vessel disease (205.7 ± 21.6 μm, and 193.7 ± 22.3 μm in normals, p = 0.03). Diabetic retinopathy correlated with an increased TIMI blush score (p = 0.01). Retinal microvascular imaging warrants further evaluation in identifying the presence, extent and nature of coronary artery disease.

Cardiac Imaging in Heart Failure with Comorbidities

Imaging modalities stand at the frontiers for progress in congestive heart failure (CHF) screening, risk stratification and monitoring. Advancements in echocardiography (ECHO) and Magnetic Resonance Imaging (MRI) have allowed for improved tissue characterizations, cardiac motion analysis, and cardiac performance analysis under stress. Common cardiac comorbidities such as hypertension, metabolic syndromes and chronic renal failure contribute to cardiac remodeling, sharing similar pathophysiological mechanisms starting with interstitial changes, structural changes and finally clinical CHF. These imaging techniques can potentially detect changes earlier. Such information could have clinical benefits for screening, planning preventive therapies and risk stratifying patients. Imaging reports have often focused on traditional measures without factoring these novel parameters. This review is aimed at providing a synopsis on how we can use this information to assess and monitor improvements for CHF with comorbidities.

Effect of Nitroglycerin on the Performance of MR Coronary Angiography

PURPOSE

To systematically investigate the effect of sublingual glyceryl trinitrate (nitroglycerin=nitro=glyceryl trinitrate=GTN=C₃ H₅ N₃ O₉ [NTG]) on the diagnostic performance of MR coronary artery imaging (MRCA) to detect relevant coronary artery disease (CAD).

MATERIALS AND METHODS

Thirty-five healthy volunteers and 25 patients with suspected or proven CAD (all in sinus rhythm) underwent MRCA before and after NTG using a contrast-agent free, three-dimensional, navigator-based, steady state free precession acquisition (voxel size 1.0 × 0.7 × 0.7 mm³ ) at 1.5 Tesla. Target parameters were stenosis detection (>50%), visible vessel length (straightened planar reconstruction) and vessel diameter (curved planar reconstruction, measured proximal/medial/distal). In patients, invasive coronary angiography served as reference.

RESULTS

NTG led to increase of the coronary diameter both in healthy volunteers (right coronary artery [RCA]: 3.2 to 3.7 mm, P < 0.001; left anterior descending coronary artery [LAD]: 2.9 to 3.4 mm, P = 0.009; left circumflex coronary artery [LCx]: 2.8 to 3.3 mm, P < 0.001) and patients (RCA 3.5 to 4.0 mm, P = 0.01; LAD 3.3 to 3.7 mm, P = 0.008; LCx: 2.9 to 3.3 mm, P = 0.03). Visible vessel length increased after NTG for the LAD (volunteers: 72 to 84 mm, P = 0.03; patients: 56 to 78 mm, P = 0.01) and for LCx (volunteers: 48 to 60 mm, P = 0.02). Sensitivity to detect > 50% stenosis improved after NTG from 88.0 to 96%, specificity from 46.5 to 69.8%, diagnostic accuracy from 61.8 to 79.4% and positive/negative predictive value from 48.9 to 64.9% and 87.0 to 96.8%, respectively.

CONCLUSION

Sublingual administration of NTG significantly enhanced the visibility of the coronary arteries and improved the detection of coronary artery stenosis.

LEVEL OF EVIDENCE

2 J. MAGN. RESON. IMAGING 2017;45:1419-1428.

"Mind the gap" acute coronary syndrome in women: A contemporary review of current clinical evidence

The incidence and prevalence of coronary artery disease in women has exceeded that in men over the past four decades, and although a significant decline in mortality has occurred in the past two decades, there is a growing body of evidence suggesting that there are gender differences between the clinical manifestations and course of coronary artery disease, as well as differences in treatment and treatment response. This review article considers the current literature regarding the gender-specific manifestation of acute coronary syndromes. Through the review of basic science articles, subsets of trial data, and meta-analyses, the gender-specific differences in within acute coronary syndromes are considered in terms of diagnostic dilemmas, pathophysiology, and treatment options (including pharmacological, percutaneous and surgical methods). Finally, acute coronary syndromes and their management in the special circumstance of pregnancy are also reviewed.

Diagnostic performance of dual-energy CT stress myocardial perfusion imaging: direct comparison with cardiovascular MRI

OBJECTIVE

The purpose of this study was to assess the diagnostic performance of stress perfusion dual-energy CT (DECT) and its incremental value when used with coronary CT angiography (CTA) for identifying hemodynamically significant coronary artery disease.

SUBJECTS AND METHODS

One hundred patients with suspected or known coronary artery disease without chronic myocardial infarction detected with coronary CTA underwent stress perfusion DECT, stress cardiovascular perfusion MRI, and invasive coronary angiography (ICA). Stress perfusion DECT and cardiovascular stress perfusion MR images were used for detecting perfusion defects. Coronary CTA and ICA were evaluated in the detection of ≥50% coronary stenosis. The diagnostic performance of coronary CTA for detecting hemo-dynamically significant stenosis was assessed before and after stress perfusion DECT on a per-vessel basis with ICA and cardiovascular stress perfusion MRI as the reference standard.

RESULTS

The performance of stress perfusion DECT compared with cardiovascular stress perfusion MRI on a per-vessel basis in the detection of perfusion defects was sensitivity, 89%; specificity, 74%; positive predictive value, 73%; negative predictive value, 90%. Per segment, these values were sensitivity, 76%; specificity, 80%; positive predictive value, 63%; and negative predictive value, 88%. Compared with ICA and cardiovascular stress perfusion MRI per vessel territory the sensitivity, specificity, positive predictive value, and negative predictive value of coronary CTA were 95%, 61%, 61%, and 95%. The values for stress perfusion DECT were 92%, 72%, 68%, and 94%. The values for coronary CTA and stress perfusion DECT were 88%, 79%, 73%, and 91%. The ROC AUC increased from 0.78 to 0.84 (p=0.02) with the use of coronary CTA and stress perfusion DECT compared with coronary CTA alone.

CONCLUSION

Stress perfusion DECT plays a complementary role in enhancing the accuracy of coronary CTA for identifying hemodynamically significant coronary stenosis.

Cardiac MR perfusion imaging: where we are

To date, several clinical and multicentre studies have demonstrated the accuracy of perfusion cardiac magnetic resonance to detect ischaemia in comparison with quantitative coronary angiography, other noninvasive diagnostic techniques (single photon emission computed tomography; positron-emission tomography), and invasive haemodynamic measurements (fractional flow reserve). Moreover, the favourable safety profile and increasing availability contribute to make perfusion cardiac magnetic resonance one of the modalities of choice for the detection of myocardial ischaemia. Recently, the first evidence of the prognostic value of perfusion cardiac magnetic resonance results has also become available. This review summarises the technical and interpretation key points of perfusion cardiac magnetic resonance scan, the clinical indications, the most recent available literature about its diagnostic performance and prognostic value, and how perfusion cardiac magnetic resonance compares with other noninvasive techniques.

Small, short-duration, dobutamine-induced perfusion defects are not associated with adverse prognosis in intermediate-risk individuals receiving cardiovascular magnetic resonance stress imaging

OBJECTIVE

The objective of this study was to assess the frequency and prognostic utility of small, short-duration left ventricular myocardial perfusion defects during dobutamine cardiovascular magnetic resonance (DCMR) stress imaging.

METHODS

We performed first-pass contrast-enhanced DCMR at peak stress in 331 consecutively recruited individuals (aged 68 ± 8 years, 50% men) at intermediate risk for a future cardiac event. Size, location, and persistence of low-signal intensity perfusion defects were recorded. Cardiac events were assessed by personnel blinded to imaging results for a median of 24 months after the DCMR.

RESULTS

Among the 55 individuals (16.6%) who exhibited small (<25% myocardial thickness) and short-duration (<5 frames in persistence) perfusion defects, diabetes was more prevalent (P = 0.019) and no cardiac events were observed. Large, persistent perfusion defects were associated with coronary artery disease, prior myocardial infarction, and decreased left ventricular function (P < 0.001 for all) and increased 2-year risk for a cardiac event (hazard ratio, 10.3; P < 0.001; confidence interval, 3.3-33.0).

CONCLUSIONS

In individuals with diabetes, hypertension, or coronary artery disease at intermediate risk for a future cardiac event, small, short-duration DCMR perfusion defects are not associated with increased 2-year risk for a subsequent cardiac event.

Diagnostic performance of non-contrast-enhanced whole-heart magnetic resonance coronary angiography in combination with adenosine stress perfusion cardiac magnetic resonance imaging

BACKGROUND

We sought to evaluate the diagnostic performance of 1.5-T non-contrast enhanced whole-heart magnetic resonance coronary angiography (MRCA) alone and in combination with adenosine stress cardiac magnetic resonance imaging (CMR-Perf). MRCA has been proposed to allow for detection of coronary artery disease (CAD). Yet, recent studies failed to show an incremental value of MRCA when added to CMR-Perf.

METHODS

Non-Gadolinium 1.5-T contrast-enhanced, electrocardiogram-triggered, navigator-gated free-breathing MRCA was performed in 144 patients (pts) with suspected or known CAD. Accuracy of MRCA in detecting CAD was evaluated using X-ray coronary angiography as the reference. A novel algorithm was used to combine the results of MRCA and CMR-Perf.

RESULTS

MRCA was diagnostic in 96/144 pts (67%) with regular breathing (mean age 62.5 ± 13); 77% of all coronary segments (939/1226) and 92% of segments suitable for percutaneous coronary intervention (792/866) were assessable. In 59 pts a novel algorithm to combine MRCA and CMR-Perf was performed with high diagnostic performance: accuracy, sensitivity, specificity, negative and positive predictive values were 91.5% (54/59; 95% CI, 84%-99%), 95.7% (22/23; 77-100), 88.9% (32/36; 74-96), 84.6% (22/26; 71-99), and 97.0% (32/33; 91-100). Compared to the combined use of CMR-Perf and late gadolinium enhancement, specificity with the novel algorithm significantly increased (P = .008).

CONCLUSION

MRCA has a high assessability in segments suitable for percutaneous coronary intervention in pts with regular breathing. The combined use of MRCA and CMR-Perf improved specificity for the detection of significant CAD.

Mechanisms of load dependency of myocardial ischemia reperfusion injury

Coronary artery disease and associated ischemic heart disease are prevalent disorders worldwide. Further, systemic hypertension is common and markedly increases the risk for heart disease. A common denominator of systemic hypertension of various etiologies is increased myocardial load/mechanical stress. Thus, it is likely that high pressure/mechanical stress attenuates the contribution of cardioprotective but accentuates the contribution of cardiotoxic pathways thereby exacerbating the outcome of an ischemia reperfusion insult to the heart. Critical events which contribute to cardiomyocyte injury in the ischemic-reperfused heart include cellular calcium overload and generation of reactive oxygen/nitrogen species which, in turn, promote the opening of the mitochondrial permeability transition pore, an important event in cell death. Increasing evidence also indicates that the myocardium is capable of mounting a robust inflammatory response which contributes importantly to tissue injury. On the other hand, cardioprotective maneuvers of ischemic preconditioning and postconditioning have led to identification of complex web of signaling pathways (e.g., reperfusion injury salvage kinase) which ultimately converge on the mitochondria to exert cytoprotection. The present review is intended to briefly describe mechanisms of cardiac ischemia reperfusion injury followed by a discussion of our work focused on how pressure/mechanical stress modulates endogenous cardiotoxic and cardioprotective mechanisms to ultimately exacerbate ischemia reperfusion injury.

Standardized image interpretation and post processing in cardiovascular magnetic resonance: Society for Cardiovascular Magnetic Resonance (SCMR) board of trustees task force on standardized post processing

With mounting data on its accuracy and prognostic value, cardiovascular magnetic resonance (CMR) is becoming an increasingly important diagnostic tool with growing utility in clinical routine. Given its versatility and wide range of quantitative parameters, however, agreement on specific standards for the interpretation and post-processing of CMR studies is required to ensure consistent quality and reproducibility of CMR reports. This document addresses this need by providing consensus recommendations developed by the Task Force for Post Processing of the Society for Cardiovascular MR (SCMR). The aim of the task force is to recommend requirements and standards for image interpretation and post processing enabling qualitative and quantitative evaluation of CMR images. Furthermore, pitfalls of CMR image analysis are discussed where appropriate.

MR myocardial perfusion imaging

Contrast material-enhanced myocardial perfusion imaging by using cardiac magnetic resonance (MR) imaging has, during the past decade, evolved into an accurate technique for diagnosing coronary artery disease, with excellent prognostic value. Advantages such as high spatial resolution; absence of ionizing radiation; and the ease of routine integration with an assessment of viability, wall motion, and cardiac anatomy are readily recognized. The need for training and technical expertise and the regulatory hurdles, which might prevent vendors from marketing cardiac MR perfusion imaging, may have hampered its progress. The current review considers both the technical developments and the clinical experience with cardiac MR perfusion imaging, which hopefully demonstrates that it has long passed the stage of a research technique. In fact, cardiac MR perfusion imaging is moving beyond traditional indications such as diagnosis of coronary disease to novel applications such as in congenital heart disease, where the imperatives of avoidance of ionizing radiation and achievement of high spatial resolution are of high priority. More wide use of cardiac MR perfusion imaging, and novel applications thereof, are aided by the progress in parallel imaging, high-field-strength cardiac MR imaging, and other technical advances discussed in this review.

Assessment of coronary artery stenosis severity and location: quantitative analysis of transmural perfusion gradients by high-resolution MRI versus FFR

OBJECTIVES

This study sought to test the hypothesis that transmural perfusion gradients (TPG) on adenosine stress myocardial perfusion cardiac magnetic resonance (CMR) predict hemodynamically significant coronary artery disease (CAD) as defined by fractional flow reserve (FFR).

BACKGROUND

Myocardial ischemia affects the subendocardial layers of the left ventricular myocardium earlier and more severely than the outer layers, and the identification of TPG should be sensitive and specific for the diagnosis of CAD. Previous studies have shown that high spatial resolution myocardial perfusion CMR allows quantitation of TPG between the subendocardium and the subepicardium.

METHODS

Sixty-seven patients (53 men, age 61 ± 9 years) underwent coronary angiography and high-resolution (1.2 × 1.2-mm in-plane) adenosine stress perfusion CMR at 3.0-T. TPG was calculated for 3 coronary territories. Visual analysis was performed to identify myocardial ischemia. FFR was measured in all vessels with ≥50% severity stenosis. FFR <0.8 was considered hemodynamically significant. In a training group of 30 patients, the optimal threshold of TPG to detect significant CAD was determined (Group 1). This threshold was then tested prospectively in the remaining 37 patients (Group 2).

RESULTS

In Group 1, a 20% TPG provided the best diagnostic threshold on both per-segment and per-patient analysis. Applied to Group 2, this threshold yielded a sensitivity of 0.78, specificity of 0.94, and area under the curve of 0.86 for the detection of CAD in a per-segment analysis and of 0.89, 0.83, and 0.86 in a per-patient analysis, respectively. TPG had a similar diagnostic accuracy to visual assessment. Linear regression analysis showed a relationship between TPG and FFR values, with r = 0.63 (p < 0.001).

CONCLUSIONS

The quantitative analysis of transmural perfusion gradients on high-resolution myocardial perfusion CMR accurately predicts hemodynamically significant CAD as defined by FFR. A TPG diagnostic threshold of 20% is as accurate as visual assessment.

Cardiovascular disease in women

Gender-specific data focused on cardiovascular disease (CVD) are becoming increasingly available. This is of great importance, given that CVD has become the number 1 killer of women, and unlike for men, mortality rates do not seem to be declining. Many factors are cited as the causes of sex-based differences, including delays in recognizing symptoms, underutilization of diagnostic tests and treatments, as well as anatomic, physiological, and genetic factors. Evidence of fundamental biological differences in vascular function and the underlying pathologic processes is only beginning to elucidated, motivated by growing evidence of differences in clinical presentations and outcomes between men and women. The good news is that we are starting to see improvements in outcomes for women, such as after coronary revascularization; decrease in complication rates with the advent of new techniques, such as radial access for cardiac catheterizations; as well as increased participation of women in clinical trials. The underlying mechanisms of ischemic heart disease remain to be elucidated, and will help guide therapy and ultimately may explain the higher prevalence of : subendocardial myocardial infarctions, spontaneous arterial dissections, plaque erosion, increased vasospastic disorders, such as coronary microvascular disease, and pulmonary hypertension in women compared with men. We have made great progress in understanding gender-related differences in CVDs, but much remains to be done to optimize the prevention of CVD for both men and women.

Myocardial ischemia in women: lessons from the NHLBI WISE study

Cardiovascular disease (CVD) remains the leading cause of death for women. For almost 3 decades, more women than men have died from CVD, with the most recent annual statistics on mortality reporting that CVD accounted for 421 918 deaths among women in the United States. Although there have been significant declines in coronary heart disease (CHD) mortality for females, these reductions lag behind those seen in men. In addition, where there has been a decrease in mortality from CHD across all age groups over time in men, in the youngest women (age <55 years) there has been a notable increase in mortality from CHD. There are differences in the prevalence, symptoms, and pathophysiology of myocardial ischemia that occurs in women compared with men. In this paper, we review the pathophysiology and mechanisms of ischemic heart disease (IHD) in women, particularly focusing on what we have learned from the WISE study. We examine the sex-specific issues related to myocardial ischemia in women in terms of prevalence and prognosis, traditional and novel risk factors, diagnostic testing, as well as therapeutic management strategies for IHD.

Strain-encoded cardiac magnetic resonance during high-dose dobutamine stress testing for the estimation of cardiac outcomes: comparison to clinical parameters and conventional wall motion readings

OBJECTIVES

The purpose of this study was to determine the prognostic value of strain-encoded magnetic resonance imaging (SENC) during high-dose dobutamine stress cardiac magnetic resonance imaging (DS-MRI) compared with conventional wall motion readings.

BACKGROUND

Detection of inducible ischemia by DS-MRI on the basis of assessing cine images is subjective and depends on the experience of the readers, which may influence not only the diagnostic classification but also the risk stratification of patients with ischemic heart disease.

METHODS

In all, 320 consecutive patients with suspected or known coronary artery disease underwent DS-MRI, using a standard protocol in a 1.5T MR scanner. Wall motion abnormalities (WMA) and myocardial strain were assessed at baseline and during stress, and outcome data including cardiac deaths, nonfatal myocardial infarctions ("hard events"), and revascularization procedures performed >90 days after the MR scans were collected.

RESULTS

Thirty-five hard events occurred during a 28 ± 9 month follow-up period, including 10 cardiac deaths and 25 nonfatal myocardial infarctions, and 32 patients underwent coronary revascularization. Using a series of Cox proportional-hazards models, both resting and inducible WMA offered incremental information for the assessment of hard cardiac events compared to clinical variables (chi-square = 13.0 for clinical vs. chi-square = 26.1 by adding resting WMA, p < 0.001, vs. chi-square = 39.3 by adding inducible WMA, p < 0.001). Adding visual SENC or quantitative strain rate reserve to this model further improved the prediction of outcome (chi-square = 50.7 vs. chi-square = 52.5, p < 0.001 for both). In a subset of patients (n = 175) who underwent coronary angiography, SENC yielded significantly higher sensitivity for coronary artery disease detection (96% vs. 84%, p < 0.02), whereas specificity and accuracy were not significantly different (88% vs. 94% and 93% vs. 88%, p = NS for both).

CONCLUSIONS

Strain-encoded MRI aids the accurate identification of patients at high risk for future cardiac events and revascularization procedures, beyond the assessment of conventional atherogenic risk factors and resting or inducible WMA on cine images. (Strain-Encoded Cardiac Magnetic Resonance Imaging as an Adjunct for Dobutamine Stress Testing; NCT00758654).

Myocardial infarction with "clean coronaries" caused by amyloid light-chain AL amyloidosis: a case report and literature review

In AL (amyloid light-chain) amyloidosis, the greatest risk of death occurs in patients with cardiac involvement, who typically develop diastolic dysfunction and then systolic heart failure, with predisposition to arrhythmias and sudden death. Here, we present an alternate variation of cardiac amyloidosis. This patient had recent non-obstructive coronary angiography, yet suffered a fatal myocardial infarction shortly after stem cell collection and mobilization in preparation for treatment with high-dose melphalan and autologous stem cell transplantation (HDM/SCT). On autopsy, widespread deposition of amyloid was found in the small vessels of the heart with evidence of associated acute infarction. While the typical presentation of cardiac amyloidosis is an infiltrating restrictive cardiomyopathy, this case report and literature review illustrate that ischemic small vessel amyloidosis may also occur. Small vessel coronary disease and associated myocardial ischemia should be considered in patients with AL amyloidosis with angina, as its presence may increase treatment-related complications. Contemporary testing should aim to detect both forms of cardiac amyloidosis, which may impact management and prognosis.

Myocardial ischemia in the absence of obstructive coronary artery disease in systemic lupus erythematosus

OBJECTIVES

the purpose of this study was to evaluate the presence of myocardial ischemia measured by adenosine stress cardiac magnetic resonance (CMR) using visual myocardial perfusion and a quantitative myocardial perfusion reserve index (MPRI) in the absence of obstructive coronary artery disease (CAD) in women with systemic lupus erythematosus (SLE) with anginal chest pain (CP).

BACKGROUND

ischemic heart disease is a leading cause of morbidity and mortality in SLE. Previous studies demonstrated the presence of perfusion defects using adenosine stress CMR in patients with CP and no obstructive CAD, consistent with microvascular coronary dysfunction in patients without SLE.

METHOD

Twenty female SLE patients with typical and atypical anginal CP were prospectively enrolled. Patients with established cardiovascular disease were excluded. CMR was performed with 0.05 mmol/kg gadolinium adenosine stress first-pass perfusion in SLE patients and in 10 asymptomatic reference control women. SLE patients also underwent 64-slice coronary computed tomography angiography. CMR was scored visually and quantitatively (MPRI).

RESULTS

among 18 patients with complete data, no patient had obstructive CAD; however, 8 of 18 (44%) displayed visual perfusion defects on stress CMR compared with 0 in 10 control subjects (p = 0.014). The mean MPRI in patients versus controls was 2.0 ± 0.4 versus 2.4 ± 0.4 (p = 0.031) in the subepicardium and 1.8 ± 0.3 versus 2.1 ± 0.4 (p = 0.24) in the subendocardium. Multivariate linear regression revealed that SLE was the only predictor of subepicardial (p < 0.0025; β = -1.059) and subendocardial (p < 0.05; β = -0.529) MPRIs.

CONCLUSIONS

we observed a 44% prevalence of abnormal stress myocardial perfusion by CMR in the absence of obstructive CAD in SLE patients with anginal CP. Compared with controls, reduced MPRI was observed in SLE patients, and SLE presence was a significant predictor of an abnormal MPRI. These findings are consistent with the hypothesis that anginal CP in SLE patients without obstructive CAD is due to myocardial ischemia potentially caused by microvascular coronary dysfunction. Further research in a larger SLE population is warranted.

Relationship between cardiac symptoms, myocardial perfusion defects and coronary angiography findings in systemic lupus erythematosus

Coronary angiography is generally regarded as the ‘gold standard’ test for diagnosing coronary artery disease (CAD). We sought to determine the relationship between cardiac symptoms and findings of coronary angiography and myocardial perfusion scintigraphy (MPS) in patients with systemic lupus erythematosus (SLE). Medical records of all SLE patients who underwent coronary angiography while attending our clinic over 24 years were reviewed, noting the indication for the test and its findings. Among patients who had MPS within 6 months prior to coronary angiography, a contingency table was used to rate the agreement between the two tests. Among the 35 patients who underwent coronary angiography, 31 had the test to investigate cardiac symptoms. Among the symptomatic patients, 17 (55%) had an abnormal angiogram with one or more plaques, while 14 (45%) had normal angiograms. All four asymptomatic patients had normal angiograms. Compared to those with normal angiograms, patients with abnormal angiograms had a higher mean number of cardiovascular risk factors per patient (1.6 ± 1.4 vs. 0.6 ± 1.0, p = 0.02). Twenty-four patients had both angiography and MPS. Overall, the agreement between angiography and MPS was poor ( κ = 0, p = 0.0008), with 14 (58.3%) patients having perfusion defects and normal angiograms. A proportion of SLE patients with cardiac symptoms do not have plaques on coronary angiography. Overall there is poor agreement between the findings of coronary angiography and MPS in SLE, suggesting mechanisms of ischemia other than plaques.

Influence of small caliber coronary arteries on the diagnostic accuracy of adenosine stress cardiac magnetic resonance imaging

Background and aims

Positive predictive value (PPV) of adenosine stress cardiac magnetic resonance (CMR) for coronary artery disease (CAD) is unsatisfactory. We investigated the impact of coronary caliber variability on this limitation in CMR performance.

Methods and results

206 consecutive patients with myocardial ischemia during CMR and subsequent coronary angiography (CA) were studied. Patients were examined in a 1.5-T scanner. After adenosine infusion, myocardial first-pass sequence using gadolinium-based contrast agent was performed and compared with rest perfusion. CAD was invasively confirmed in 165 [true positive (TP); PPV, 80.1%] and ruled out in 41 patients [false positive (FP)]. TP and FP were comparable for pre-test risk and CMR findings. We found a significant association between FP CMR and the presence of a small caliber coronary vessel (proximal diameter < one standard deviation below the mean) supplying the area of ischemia (chi-square 42.6, p < 0.0001). A small caliber artery ipsilateral to the ischemic region was a predictive parameter for FP versus TP discrimination (ROC area, 0.84 ± 0.04 vs. 0.59 ± 0.05; p < 0.0001). Further increment in diagnostic accuracy was achieved by including proximal ipsilateral/contralateral coronary diameter ratios (ROC area, 0.90 ± 0.03; p < 0.03).

Conclusions

Small caliber coronary arteries found as normal variations in right-dominant or left-dominant circulation may account for hypoperfusion in the absence of coronary stenosis and thus may cause FP adenosine stress CMR results. Non-invasive assessment of proximal coronary diameters in the vessel supplying the area of ischemia could reduce FP rates, raise the diagnostic accuracy of CMR for CAD and minimize subsequent superfluous CA.

Role of cardiovascular imaging in systemic autoimmune diseases

Systemic autoimmune diseases are characterized by an excess of cardiovascular (CV) morbidity and mortality compared to the general population, mainly due to chronic inflammation that promotes the development of endothelial dysfunction and enhanced atherosclerosis. Early diagnosis of silent CV involvement is mandatory to improve the long term prognosis of these patients and CV imaging provides valuable information as a reliable diagnostic tool. Transthoracic echocardiography, with several applications (e.g. coronary flow reserve evaluation, tissue Doppler imaging, speckle tracking and the transesophageal approach), represents a first line evaluation, in association with biomarkers of endothelial dysfunction, such as asymmetric dimethylarginine. Nuclear medicine provides useful information on myocardial perfusion. The aim of this editorial is to provide a brief but complete review of the diagnostic tools available for screening and follow up of CV involvement in systemic autoimmune diseases.

Hypertension impairs myocardial blood perfusion reserve in subjects without regional myocardial ischemia

Quantitative analysis of myocardial perfusion MRI can provide noninvasive assessments of myocardial perfusion reserve (MPR), which is associated with endothelial function. Endothelial function is influenced by various factors, including hypertension, diabetes, dyslipidemia, renal dysfunction and anemia. The purpose of this study was to evaluate which risk factor is the strongest effector of MPR in subjects without regional myocardial ischemia. We studied 110 patients (66 years ±10, male 68%, hypertension 76%, diabetes mellitus (DM) 40% and dyslipidemia 65%) without regional myocardial ischemia. Adenosine triphosphate (ATP) stress and rest first-pass perfusion magnetic resonance (MR) images were acquired with a 1.5-T MR system, and MPR was calculated as the ratio of stress to rest myocardial blood flow (MBF). Average rest MBF in 110 patients was 1.07±0.62 ml min⁻¹ g⁻¹, whereas stress MBF was 3.15±1.93 ml min⁻¹ g⁻¹ and the MPR was 3.33±1.82. Rest MBF correlated significantly with hematocrit, whereas stress MBF showed a strong correlation with estimated glomerular filtration rate (e-GFR). MPR was associated with hypertension, age, e-GFR, hematocrit and left ventricular mass index (LVMI). In multiple regression analysis, hypertension (P=0.003, β=-0.274) showed the strongest correlation with MPR among other risk factors, such as diabetes (P=ns), dyslipidemia (P=ns), e-GFR (P=ns), LVMI (P=0.007, β=-0.248) and hematocrit (P=ns) after adjusting age and gender. Hypertension is the most important effector of MPR in subjects without myocardial ischemia.

Myocardial perfusion imaging using adenosine-induced stress dual-energy computed tomography of the heart: comparison with cardiac magnetic resonance imaging and conventional coronary angiography

OBJECTIVE

To evaluate the feasibility and diagnostic accuracy of adenosine-stress dual-energy computed tomography (DECT) for detecting haemodynamically significant stenosis causing reversible myocardial perfusion defect (PD) compared with stress perfusion magnetic resonance imaging (SP-MRI) and conventional coronary angiography (CCA).

METHODS

Fifty patients with known coronary artery disease (CAD) detected by dual-source CT (DSCT) were investigated by contrast-enhanced, stress DECT with high- and low-energy x-ray spectra settings during adenosine infusion. A colour-coded iodine map was used for evaluation of myocardial PDs compared with rest DSCT perfusion images. Reversible myocardial PDs according to the stress DECT/rest DSCT were compared with SP-MRI on a segmental basis and CCA on a vascular territorial basis.

RESULTS

A total of 697 myocardial segments and 123 vascular territories of 41 patients were analysed. Three hundred one segments and 72 vascular territories in 38 patients showed reversible PDs on stress DECT. Stress DECT had 89% sensitivity, 78% specificity and 82% accuracy for detecting segments with reversible PDs seen on SP-MRI (n=28). Compared with CCA (n=41), stress DECT had 89% sensitivity, 76% specificity and 83% accuracy for the detection of vascular territories with reversible myocardial PDs that had haemodynamically relevant CAD.

CONCLUSION

Adenosine stress DECT can identify stress-induced myocardial PD in patients with CAD.

Adenosine-stress cardiac magnetic resonance imaging in suspected coronary artery disease: a net cost analysis and reimbursement implications

The health and economic implications of new imaging technologies are increasingly relevant policy issues. Cardiac magnetic resonance imaging (CMR) is currently not or not sufficiently reimbursed in a number of countries including Germany, presumably because of a limited evidence base. It is unknown, however, whether it can be effectively used to facilitate medical decision-making and reduce costs by serving as a gatekeeper to invasive coronary angiography. We investigated whether the application of CMR in patients suspected of having coronary artery disease (CAD) reduces costs by averting referrals to cardiac catheterization. We used propensity score methods to match 218 patients from a CMR registry to a previously studied cohort in which CMR was demonstrated to reliably identify patients who were low-risk for major cardiac events. Covariates over which patients were matched included comorbidity profiles, demographics, CAD-related symptoms, and CAD risk as measured by Morise scores. We determined the proportion of patients for whom cardiac catheterization was deferred based upon CMR findings. We then calculated the economic effects of practice pattern changes using data on cardiac catheterization and CMR costs. CMR reduced the utilization of cardiac catheterization by 62.4%. Based on estimated catheterization costs of € 619, the utilization of CMR as a gatekeeper reduced per-patient costs by a mean of € 90. Savings were realized until CMR costs exceeded € 386. Cost savings were greatest for patients at low-risk for CAD, as measured by baseline Morise scores, but were present for all Morise subgroups with the exception of patients at the highest risk of CAD. CMR significantly reduces the utilization of cardiac catheterization in patients suspected of having CAD. Per-patient savings range from € 323 in patients at lowest risk of CAD to € 58 in patients at high-risk but not in the highest risk stratum. Because a negative CMR evaluation has high negative predictive value, its application as a gatekeeper to cardiac catheterization should be further explored as a treatment option.

Current status of cardiovascular magnetic resonance imaging in the assessment of coronary vasculature

The present review describes the contributions of cardiovascular magnetic resonance (CMR) imaging to the assessment of coronary vasculature. It briefly describes various approaches and highlights the value of comprehensive CMR protocols. The limitations of coronary angiography for clinical decision-making and the additional value of plaque imaging and tissues characterization, as well as future directions of CMR and hybrid techniques for assessing microvascular function and myocardial oxygenation, are discussed.

Meta-analysis of the diagnostic performance of stress perfusion cardiovascular magnetic resonance for detection of coronary artery disease

AIM

Evaluation of the diagnostic accuracy of stress perfusion cardiovascular magnetic resonance for the diagnosis of significant obstructive coronary artery disease (CAD) through meta-analysis of the available data.

METHODOLOGY

Original articles in any language published before July 2009 were selected from available databases (MEDLINE, Cochrane Library and BioMedCentral) using the combined search terms of magnetic resonance, perfusion, and coronary angiography; with the exploded term coronary artery disease. Statistical analysis was only performed on studies that: (1) used a [greater than or equal to] 1.5 Tesla MR scanner; (2) employed invasive coronary angiography as the reference standard for diagnosing significant obstructive CAD, defined as a [greater than or equal to] 50% diameter stenosis; and (3) provided sufficient data to permit analysis.

RESULTS

From the 263 citations identified, 55 relevant original articles were selected. Only 35 fulfilled all of the inclusion criteria, and of these 26 presented data on patient-based analysis. The overall patient-based analysis demonstrated a sensitivity of 89% (95% CI: 88-91%), and a specificity of 80% (95% CI: 78-83%). Adenosine stress perfusion CMR had better sensitivity than with dipyridamole (90% (88-92%) versus 86% (80-90%), P = 0.022), and a tendency to a better specificity (81% (78-84%) versus 77% (71-82%), P = 0.065).

CONCLUSION

Stress perfusion CMR is highly sensitive for detection of CAD but its specificity remains moderate.

The hypertensive heart. An integrated understanding informed by imaging

Clinical sequelae of hypertension include heart failure, arrhythmias, and ischemic events, especially myocardial infarction and stroke. Recognizing the hypertensive heart has diagnostic as well as prognostic implications. Current imaging techniques offer noninvasive approaches to detecting myocardial fibrosis, ischemia, hypertrophy, and disordered metabolism that form the substrate for hypertensive heart disease. In addition, recognition of aortopathy and atrial myopathy as contributors to myocardial disease warrant incorporation of aortic and atrial functional measurements into a comprehensive understanding of the hypertensive heart.

Comprehensive adenosine stress perfusion MRI defines the etiology of chest pain in the emergency room: Comparison with nuclear stress test

PURPOSE

To compare standard of care nuclear SPECT imaging with cardiac magnetic resonance imaging (MRI) for emergency room (ER) patients with chest pain and intermediate probability for coronary artery disease.

MATERIALS AND METHODS

Thirty-one patients with chest pain, negative electrocardiogram (ECG), and negative cardiac enzymes who underwent cardiac single photon emission tomography (SPECT) within 24 h of ER admission were enrolled. Patients underwent a comprehensive cardiac MRI exam including gated cine imaging, adenosine stress and rest perfusion imaging and delayed enhancement imaging. Patients were followed for 14 +/- 4.7 months.

RESULTS

Of 27 patients, 8 (30%) showed subendocardial hypoperfusion on MRI that was not detected on SPECT. These patients had a higher rate of diabetes (P = 0.01) and hypertension (P = 0.01) and a lower global myocardial perfusion reserve (P = 0.01) compared with patients with a normal cardiac MRI (n = 10). Patients with subendocardial hypoperfusion had more risk factors for cardiovascular disease (mean 4.4) compared with patients with a normal MRI (mean 2.5; P = 0.005). During the follow-up period, patients with subendocardial hypoperfusion on stress MRI were more likely to return to the ER with chest pain compared with patients who had a normal cardiac MRI (P = 0.02). Four patients did not finish the MR exam due to claustrophobia.

CONCLUSION

In patients with chest pain, diabetes and hypertension, cardiac stress perfusion MRI identified diffuse subendocardial hypoperfusion defects in the ER setting not seen on cardiac SPECT, which is suspected to reflect microvascular disease.

Women and ischemic heart disease: evolving knowledge

Evolving knowledge regarding sex differences in coronary heart disease is emerging. Given the lower burden of obstructive coronary artery disease (CAD) and preserved systolic function in women, which contrasts with greater rates of myocardial ischemia and near-term mortality compared with men, we propose the term "ischemic heart disease" as appropriate for this discussion specific to women rather than CAD or coronary heart disease (CHD). This paradoxical difference, where women have lower rates of anatomical CAD but more symptoms, ischemia, and adverse outcomes, appears linked to abnormal coronary reactivity that includes microvascular dysfunction. Novel risk factors can improve the Framingham risk score, including inflammatory markers and reproductive hormones, as well as noninvasive imaging and functional capacity measurements. Risk for women with obstructive CAD is increased compared with men, yet women are less likely to receive guideline-indicated therapies. In the setting of non-ST-segment elevation acute myocardial infarction, interventional strategies are equally effective in biomarker-positive women and men, whereas conservative management is indicated for biomarker-negative women. For women with evidence of ischemia but no obstructive CAD, antianginal and anti-ischemic therapies can improve symptoms, endothelial function, and quality of life; however, trials evaluating impact on adverse outcomes are needed. We hypothesize that women experience more adverse outcomes compared with men because obstructive CAD remains the current focus of therapeutic strategies. Continued research is indicated to devise therapeutic regimens to improve symptom burden and reduce risk in women with ischemic heart disease.

Hypertension and myocardial ischemia

Detailed studies over the past 30 years have built up an impressive evidence base for the presence of myocardial ischemia in patients who have hypertension. This relationship ranges from the obvious association with obstructive coronary artery disease to mechanisms related to hemodynamic, microcirculatory, and neuroendocrine abnormalities. All of these factors serve to destabilize the critical balance between myocardial oxygen supply and demand. We have at our disposal a range of sophisticated investigations that allow us to demonstrate the presence and extent of the ischemia and therefore to target specific therapies to reduce the risk to these patients. Achieving target BP and managing all reversible components of the patient's cardiovascular risk status reduce to a minimum the clinical sequelae of myocardial ischemia in this vulnerable population..

Combined myocardial stress perfusion imaging and myocardial stress tagging for detection of coronary artery disease at 3 Tesla

BACKGROUND

Adenosine stress perfusion is very sensitive for detection of coronary artery disease (CAD), and yields good specificity. Standard adenosine cine imaging lacks high sensitivity, but is very specific. Myocardial tagging improves detection of wall motion abnormalities (WMAs). Perfusion and tagging cardiovascular magnetic resonance (CMR) both benefit from high field imaging (improved contrast to noise ratio and tag persistence). We investigated the diagnostic impact of a combined stress perfusion-tagging protocol for detection of CAD at 3 Tesla.

METHODS

Stress perfusion and tagging images were acquired in 3 identical short axis locations (slice thickness 8 mm, FOV 320-380 mm, matrix 256(2)). A positive finding at coronary angiography was defined as stenosis or flow limiting restenosis > 50% in native and graft vessels. A true positive CMR - finding was defined as > or = 1 perfusion deficit or new WMA during adenosine-stress in angiographically corresponding regions.

RESULTS

We included 60 patients (males: 41, females: 19; 21 suspected, 39 known CAD). Myocardial tagging extended stress imaging by 1.5-3 min and was well tolerated by all patients. Sensitivity and specificity for detection of significant CAD by adenosine stress perfusion were 0.93 and 0.84, respectively. The sensitivity of adenosine stress tagging was less (0.64), while the specificity was very high (1.0). The combination of both stress perfusion and stress tagging did not increase sensitivity.

CONCLUSION

The combined adenosine stress perfusion-tagging protocol delivers high sensitivity and specificity for detection of significant CAD. While the sensitivity of adenosine stress tagging is poor compared to perfusion imaging, its specificity is very high. This technique should thus prove useful in cases of inconclusive perfusion studies to help avoid false positive results.