Guidelines for clinical use of cardiac radionuclide imaging. Report of the American College of Cardiology/American Heart Association Task Force on Assessment of Diagnostic and Therapeutic Cardiovascular Procedures (Committee on Radionuclide Imaging), developed in collaboration with the American Society of Nuclear Cardiology

Characterization of the Changes in Cardiac Structure and Function in Mice Treated With Anthracyclines Using Serial Cardiac Magnetic Resonance Imaging

BACKGROUND

Anthracyclines are cardiotoxic; however, there are limited data characterizing the serial changes in cardiac structure and function after anthracyclines. The aim of this study was to use cardiac magnetic resonance to characterize anthracycline-induced cardiotoxicity in mice.

METHODS AND RESULTS

This was a longitudinal cardiac magnetic resonance and histological study of 45 wild-type male mice randomized to doxorubicin (n=30, 5 mg/kg of doxorubicin/week for 5 weeks) or placebo (n=15). A cardiac magnetic resonance was performed at baseline and at 5, 10, and 20 weeks after randomization. Measures of primary interest included left ventricular ejection fraction, myocardial edema (multiecho short-axis spin-echo acquisition), and myocardial fibrosis (Look-Locker gradient echo). In doxorubicin-treated mice versus placebo, there was an increase in myocardial edema at 5 weeks (T2 values of 32±4 versus 21±3 ms; P<0.05), followed by a reduction in left ventricular ejection fraction (54±6 versus 63±5%; P<0.05) and an increase in myocardial fibrosis (extracellular volume of 0.34±0.03 versus 0.27±0.03; P<0.05) at 10 weeks. There was a strong association between the early (5 weeks) increase in edema and the subacute (10 weeks) increase in fibrosis (r=0.90; P<0.001). Both the increase in edema and fibrosis predicted the late doxorubicin-induced mortality in mice (P<0.001).

CONCLUSIONS

Our data suggest that, in mice, anthracycline-induced cardiotoxicity is associated with an early increase in cardiac edema and a subsequent increase in myocardial fibrosis. The early increase in edema and subacute increase in fibrosis are strongly linked and are both predictive of late mortality.

Cardiovascular imaging in the diagnosis and monitoring of cardiotoxicity: role of echocardiography

The evaluation by cardiovascular imaging of chemotherapy patients became a central topic in the last several years. The use of drugs for the treatment of cancers increased, and new molecules and protocols were developed to improve outcomes in these patients. Although, these novel approaches also produced a progressive increase in side effects, particularly myocardial dysfunction. Imaging of the heart was highly accurate in the early diagnosis of cancer therapeutics related-cardiac dysfunction. Echocardiography is the first-line method to assess ventricular function alterations, and it is required to satisfy the need for an early, easy and accurate diagnosis to stratify the risk of heart failure and manage treatments. A careful monitoring of cardiac function during the course of therapy should prevent the onset of severe heart impairment. This review provides an overview of the most important findings of the role of echocardiography in the management of chemotherapy-treated patients to create a clear and complete description of the efficacy of conventional measurements, the importance of comprehensive heart evaluations, the additional role of new echocardiographic techniques, the utility of integrated studies using other imaging tools and the positions of the most important international societies on this topic.

Biomarkers for the early detection of anthracycline-induced cardiotoxicity: current status

BACKGROUND

Cardiotoxicity is a well-known and potentially serious complication of anticancer therapy. Anthracycline-based chemotherapy represents the greatest risk. Early detection of cardiotoxicity is crucial for applying preventive and supportive therapeutic strategies.

METHODS AND RESULTS

Various methods have been recommended for monitoring of cardiotoxicity. In our conditions, echocardiography and electrocardiography are routinely used. However, this approach shows low sensitivity for the early prediction of cardiomyopathy when the possibilities of appropriate management could still improve the patient's outcome. Recently, biomarkers of cardiac injury have been investigated in the assessment of chemotherapy-induced cardiotoxicity. Cardiospecific biomarkers, such as cardiac troponins, show high diagnostic efficacy in the early subclinical phase of the disease before the clinical onset of cardiomyopathy. Increase in their concentrations correlates with disease severity. As for natriuretic peptides, some studies, including ours, have shown promising results. Definitive evidence of their diagnostic and prognostic role in this context is still lacking and natriuretic peptides have not been routinely used for monitoring of cardiotoxicity in clinical practice. Other perspective biomarkers of cardiotoxicity in oncology are under study, especially heart-type fatty acid-binding protein (H-FABP) and glycogen phosphorylase BB (GPBB). Our studies using GPBB have provided encouraging results. However, the available data are limited and their practical use in this context cannot be recommended until their clinical efficacy is clearly defined.

CONCLUSIONS

This review covers the current status of biomarkers for the early detection of anthracycline-induced cardiotoxicity. The authors present in brief, their own experience with multiple biomarkers in the detection of cardiotoxicity.

Regadenoson-stress myocardial CT perfusion and single-photon emission CT: rationale, design, and acquisition methods of a prospective, multicenter, multivendor comparison

Pharmacologic stress myocardial CT perfusion (CTP) has been reported to be a viable imaging modality for detection of myocardial ischemia compared with single-photon emission CT (SPECT) in several single-center studies. However, regadenoson-stress CTP has not previously been compared with SPECT in a multicenter, multivendor study. The rationale and design of a phase 2, randomized, cross-over study of regadenoson-stress myocardial perfusion imaging by CTP compared with SPECT are described herein. The study will be conducted at approximately 25 sites by using 6 different CT scanner models, including 64-, 128-, 256-, and 320-slice systems. Subjects with known/suspected coronary artery disease will be randomly assigned to 1 of 2 imaging procedure sequences; rest and regadenoson-stress SPECT on day 1, then regadenoson-stress CTP and rest CTP/coronary CT angiography (same acquisition) on day 2; or regadenoson-stress CTP and rest CTP/CT angiography on day 1, then rest and regadenoson-stress SPECT on day 2. The prespecified primary analysis examines the agreement rate between CTP and SPECT for detecting or excluding ischemia (≥2 or 0-1 reversible defects, respectively), as assessed by 3 independent blinded readers for each modality. Non-inferiority will be indicated if the lower boundary of the 95% CI for the agreement rate is within 0.15 of 0.78 (the observed agreement rate in the regadenoson pivotal trials). The protocol described herein will support the first evaluation of regadenoson-stress CTP by using multiple scanner types compared with SPECT.

[Myocardial revascularization]

Coronary artery disease (CAD) is a leading cause of morbidity and mortality in western countries and is of significant socio-economic importance due to its increasing prevalence. Until percutaneous coronary interventions (PCI) were established, CAD could only be treated by surgical revascularization or pharmacological therapy. In-stent restenosis remains a major problem after stent implantation. However, the use of new materials and stent coatings have led to a significant reduction in in-stent restenosis. Thus, surgical revascularization and PCI are currently of equal value for the treatment of CAD. The decision-making for PCI or surgical revascularization depends on various factors such as number of diseased vessels, complexity of the coronary stenoses, concomitant diseases, and the patient's general condition. The therapeutic regime of every patient should be adjusted to the recommendations of the European and German Society for Cardiology, while controversial and complex cases should be discussed in an interdisciplinary case conference ("heart team").

Managing cardiotoxicity of chemotherapy

OPINION STATEMENT

The increase in survivorship of cancer patients makes the understanding of the available options for prevention and treatment of cardiotoxicity induced by antineoplastic agents a crucial topic both for cardiologists and oncologists. The most frequent and typical clinical manifestation of cardiotoxicity is asymptomatic or symptomatic left ventricular dysfunction, which may progress to overt heart failure. It may be induced not only by conventional cancer therapy, like anthracyclines, but also by new antitumoral targeted therapy such as trastuzumab. The current standard for monitoring cardiac damage during antineoplastic treatment, mainly based on the quantification of left ventricular ejection fraction, detects cardiac toxicity only when a functional impairment has already occurred. Evaluation of cardiac biomarkers such as troponin, however, has shown excellent sensitivity in the early detection of cardiotoxicity by the identification of patients with subclinical cardiac injury that precedes the development of cardiac dysfunction. The use of angiotensin-converting enzyme inhibitors in patients with troponin elevation during chemotherapy may be an effective tool to prevent left ventricular ejection fraction reduction and late cardiac events. There are no well established recommendations for treatment of cancer patients who develop cardiac dysfunction. Angiotensin-converting enzyme inhibitors and beta-blockers have proven to be effective in this setting. However, there are concerns in using these medications in cancer patients, and therefore the tendency is to treat patients only if symptomatic. However, the clinical benefit of these medications may be more evident in asymptomatic patients, and the recovery of cardiac function strongly depends on the amount of time elapsed from the end of chemotherapy to the start of heart failure therapy. This observation suggests that the early detection of cardiac damage is crucial and early use of angiotensin-converting enzyme inhibitors and beta-blockers should be considered in patients with left ventricular dysfunction induced by antineoplastic agents.

Use of echocardiography to evaluate the cardiac effects of therapies used in cancer treatment: what do we know?

Cardiologists and oncologists today face the daunting challenge of identifying patients at risk for late-onset left ventricular (LV) systolic dysfunction from the use of various chemotherapeutic agents. Currently, the most widely used method in clinical practice for monitoring the potential of chemotherapy-induced cardiotoxicity is calculation of LV ejection fraction. The use of LV ejection fraction to determine whether to continue or discontinue the use of chemotherapeutic agents is limited, because decreases in LV ejection fraction frequently occur late and can be irreversible. These limitations have led to the exploration of diastolic function and newer modalities that assess myocardial mechanics to identify sensitive and specific variables that can predict the occurrence of late systolic function. The cancer therapies associated with cardiotoxicity are reviewed in this report. Additionally, the authors evaluate the role of present-day echocardiographic parameters, complementary noninvasive imaging modalities, and biomarkers in the prediction of cardiotoxicity. The authors address the evolving role of cardioprotective agents and potential therapies to prevent or reverse the progression of LV systolic dysfunction. Finally, they provide some ideas regarding future directions to enhance the knowledge of predicting late-onset LV systolic dysfunction secondary to cancer therapy.

[Myocardial revascularization]

Coronary artery disease (CAD) is a leading cause of morbidity and mortality in western countries and is of significant socio-economic importance due to its increasing prevalence. Until percutaneous coronary interventions (PCI) were established, CAD could only be treated by surgical revascularization or pharmacological therapy. In-stent restenosis remains a major problem after stent implantation. However, the use of new materials and stent coatings have led to a significant reduction in in-stent restenosis. Thus, surgical revascularization and PCI are currently of equal value for the treatment of CAD. The decision-making for PCI or surgical revascularization depends on various factors such as number of diseased vessels, complexity of the coronary stenoses, concomitant diseases, and the patient's general condition. The therapeutic regime of every patient should be adjusted to the recommendations of the European and German Society for Cardiology, while controversial and complex cases should be discussed in an interdisciplinary case conference ("heart team").

Transthoracic electrical bioimpedence cardiac output: comparison with multigated equillibrium radionuclide cardiography

INTRODUCTION

Thoracic electrical bioimpedance (TEB) for measuring cardiac output (CO) is being explored increasingly as an alternative to pulmonary artery catheter. The major advantage of this technology is that it is non-invasive and easy to perform. Several studies have compared it to thermodilution cardiac output using PA catheter, with variable correlation. Multigated radionuclide equilibrium cardiography (RNEC) method of cardiac output measurement is known to be reliable.

OBJECTIVE

To compare cardiac output measured by thoracic electrical bioimpdenace with that measured by multigated radionuclide equilibrium cardiography.

PATIENTS AND METHODS

CO studies were performed sequentially at a single sitting by TEB and RNEC methods among patients with cardiac symptoms referred for radionuclide study as part of their evaluation. TEB CO was measured by placing two pairs of electrodes on either side of neck and two other pairs on either side of the lower chest. Stroke volume was estimated from the sequential changes in transthoracic electrical bioimpedance induced by rhythmic aortic blood flow, using Kubicek equation. RNEC-CO was measured by intravenous injection of radio-active Technitium-tagged RBCs followed by ECG gated blood pool imaging over the chest (MUGA study). Bland-Altman analysis was used to compare the measurements.

RESULTS

A total of 32 subjects with proven or suspected ischemic heart disease, but without overt cardiac failure, edema or arrhythmias were studied (M:F::26:6; mean age: 48 +/- 12 years). The mean TEB-CO was 3.54 +/- 1.052 l/min and mean RNEC-CO was 3.907 +/- 0.952 l/min. Correlation coefficient (r) for these measurements was 0.67 (p < 0.01), with bias: -0.421 l/min; precision: 1.557 l/min; and percentage error of measurement: 42.35%.

CONCLUSIONS

This study observed a moderate correlation between TEB and RNEC methods of CO measurement. Further studies are indicated to explore the relative utility of TEB in comparison with RNEC as well as other methods of CO measurement before considering its use in patients with ischemic heart disease.

Perspectives of nuclear diagnostic imaging in diabetic cardiomyopathy

Diabetic cardiomyopathy is a ventricular dysfunction in the absence of coronary artery disease, valvular or hypertensive heart disease. The mechanisms underlying diabetic cardiomyopathy may involve metabolic disturbances, myocardial fibrosis, small vessel disease, microcirculation abnormalities, cardiac autonomic neuropathy and insulin resistance. Diagnostic problems emerge because no specific disease pattern characterizes the disease and because there may be coexistence in diabetes of coronary artery disease and hypertension as independent but compounding causes of biochemical, anatomical and functional alterations impairing cardiac function. In this paper we will review the role of nuclear imaging today, concentrating on the diagnostic capabilities of radionuclide ventriculography, to study the effect of insulin resistance and, more extensively, gated-single photon emission computed tomography with Tc-99m labelled agents. A broad analysis will be dedicated to: 1) positron emission tomography using perfusion agents, with the potential to quantify resting and stress blood flow and coronary flow reserve; 2) radionuclide procedures evaluating aerobic and anaerobic cardiac metabolism; and 3) cardiac neurotransmission imaging, studying the autonomic neuropathy.

Assessing the appropriateness of coronary revascularization: the University of Maryland Revascularization Appropriateness Score (RAS) and its comparison to RAND expert panel ratings and American College of Cardiology/American Heart Association guidelines with regard to assigned appropriateness rating and ability to predict outcome

BACKGROUND

Significant regional variation in procedural frequencies has led to the development of the RAND and American College of Cardiology/American Heart Association (ACC/AHA) guidelines; however, they may be difficult to apply in clinical practice. The University of Maryland Revascularization Appropriateness Score (RAS) was created to address the need for a simplified point scoring system.

HYPOTHESIS

The study was undertaken to compare revascularization appropriateness ratings yielded by the RAND Expert Panel Ratings, ACC/AHA guidelines, and the University of Maryland RAS.

METHODS

We applied these three revascularization appropriateness scoring systems to 153 catheterization laboratory patients with a variety of cardiac diagnoses and treatments. For each patient, appropriateness scores assigned by each of the three systems were compared with each other and with the actual treatment delivered. Concordance of care with appropriateness score was then correlated with outcome.

RESULTS

There were significant differences among all three scoring systems in their ratings and in the concordance of treatment with appropriateness rating. When treatment provided was concordant with RAND ratings, there was a lower occurrence of subsequent coronary artery bypass grafting (CABG), the composite end point of either CABG or percutaneous transluminal coronary angioplasty (PTCA), and the composite end point of death, myocardial infarction (MI), or revascularization. When treatment was concordant with the ACC/AHA guidelines, there was lower occurrence of all-cause mortality, PTCA, the composite end point of either CABG or PTCA, and the composite end point of death, MI, or revascularization. When treatment provided was concordant with the RAS, there was lower occurrence of cardiac death, all-cause death, CABG, the composite end point of either CABG or PTCA, and the composite end point of death, MI, or revascularization.

CONCLUSIONS

The RAS is a simple scoring system to assess revascularization appropriateness. When the RAND, ACC/AHA, and RAS systems are compared in a catheterization laboratory population, they rate the same patient differently and vary in their correlation of appropriateness rating with outcome.

Cardio-oncology: a new medical issue

Due to the increasing number of long-term cancer survivors, the ageing of the population, as well as the increased incidence and prevalence of oncologic and cardiovascular diseases, the number of patients presenting oncologic and cardiologic co-morbidities are increasing. Accordingly, there is a rapidly growing need for a comprehensive and proficient management of patients in whom the two co-morbidities exist, and for cancer patients whose clinical history and oncologic treatment put them at higher risk for developing cardiovascular problems, in order to provide the optimal treatment in every situation, and to avoid the possibility that the development of the second disease does not lead to a reduction of therapeutic opportunities for the patient. A new discipline, cardio-oncology, has been created to deal with this need. Its aim is to investigate new strategies, collect new evidence-based indications and develop interdisciplinary expertise in order to manage this growing category of patients. Cardio-oncology deals with the following main clinical and research areas: early diagnosis of cardiotoxicity, risk stratification and preventions, treatment and monitoring of cardiotoxicity.

Prognostic significance of myocardial ischemia by dobutamine stress echocardiography in patients without angina pectoris after coronary revascularization

The clinical utility of stress testing in patients without angina pectoris after revascularization has been questioned. Dobutamine stress echocardiography (DSE) is an established technique for detection of myocardial ischemia and cardiac risk stratification. We studied the prognostic value of DSE in 393 patients without typical angina pectoris after coronary revascularization. Ischemia was incremental to clinical data in predicting all-cause death (hazard ratio 3.5, 95% confidence interval 1.8 to 6.7) and cardiac death (hazard ratio 4.2, 95% confidence interval 1.8 to 9.8). In conclusion, myocardial ischemia during DSE is independently associated with an increased risk of all-cause mortality and cardiac death in these patients after adjustment for clinical data.

Anthracycline-induced chronic cardiotoxicity and heart failure

Anthracyclines are effective drugs used in a wide range of malignant diseases. The drugs have frequent, serious adverse effects including cardiotoxicity and resulting heart failure. Systematic reviews, meta-analyses and other relevant studies were identified using the Cochrane and the Medline databases. Chronic cardiotoxicity and heart failure may complicate anthracycline treatment often months to years after treatment has ended. Risk factors including diverse cardiac diseases increase the risk of chronic cardiotoxicity. Screening for impairment of left ventricular function with echocardiography or radionuclide ventriculography is recommended. Search for new sensitive methods has been prompted to predict development of heart failure at an early stage enabling to modify the chemotherapeutic regimen, to include cardiac protectants or to initiate treatment.

Early Epirubicin‐Induced Myocardial Dysfunction Revealed by Serial Tissue Doppler Echocardiography: Correlation with Inflammatory and Oxidative Stress Markers

A phase II, open, nonrandomized trial was carried out in a group of epirubicin-treated patients with cancer at different sites with the aim of detecting early preclinical changes that are predictive of the risk for heart failure. All patients underwent conventional echocardiography, as well as tissue Doppler imaging (TDI) with strain (sigma) and strain rate (SR), a very accurate technique for detecting minimal changes in cardiac left ventricular (LV) function. Moreover, echocardiographic changes identified during epirubicin treatment were compared with those of a series of biochemical markers of both myocardial damage and inflammation/oxidative stress. Sixteen patients (male-to-female ratio, 3:13; mean age +/- standard deviation, 56 +/-3 years; range, 27-75 years) with histologically confirmed tumors at different sites, scheduled to be treated with an epirubicin-based chemotherapy regimen, were enrolled in the study. A significant impairment in systolic LV function was observed after 200 mg/m2 of epirubicin; this was shown by a lower SR peak compared with baseline (1.82 +/- 0.57/second versus 1.45 +/- 0.44/second), whereas sigma remained unchanged. The following significant changes in LV diastolic function occurred only after 300 mg/m2 of epirubicin: a decrease in conventional early/late diastolic (E/A) velocities (1.16 +/- 0.31 versus 0.93 +/- 0.24) and a reduction in both the E(m) wave in the basal portion of the interventricular septum (8.86 +/- 1.73 cm/second versus 7.51 +/- 2.30 cm/second) and in the E(m)/A(m) ratio (1.09 +/- 0.51 versus 0.83 +/- 0.51), as measured using the TDI technique. No significant changes in LV ejection fraction were observed. Baseline values of brain natriuretic peptide, troponin I, myoglobin, and creatine kinase-myocardial subfraction were within the normal range and no significant changes were observed throughout the study. Levels of interleukin (IL)-6 and its soluble receptor (sIL-6R) and reactive oxygen species increased significantly, whereas glutathione peroxidase (GPx) levels decreased significantly, after 200 mg/m2 of epirubicin. Significant correlations between the reduction in the SR peak (deltaSR) after 200 mg/m2 of epirubicin and the increase in IL-6 and ROS and decrease in GPx were observed. The multiple regression analysis showed that the only independent predictive variable for deltaSR was ROS level. Our data show that: (a) subtle cardiac abnormalities may occur at epirubicin doses significantly below those known to be potentially clinically harmful and (b) the earliest myocardial impairment affects LV systolic rather than diastolic function. Early contractility impairment during epirubicin treatment was associated with high levels of ROS and markers of inflammation. The clinical meaningfulness of our findings warrants further investigations in a larger number of patients for a longer period of follow-up.

Light and shadows in the iron chelation treatment of haematological diseases

This review outlines the main chelator groups studied to date, and the evidence for their clinical effectiveness. For each treatment, the strength of evidence was documented according to the guidelines from the American College of Cardiology and the American Heart Association. Three main haematological diseases were considered as models: thalassaemia major, sickle-cell disorders and myelodysplasia. Although the data in the literature do not allow firmly evidence-based conclusions, the findings suggest that in thalassaemia major: (i) deferoxamine remains the drug of choice for chelation treatment; (ii) if there is deferoxamine intolerance or a change of treatment is suggested, the options are deferiprone or, if the liver iron concentration is high, deferasirox treatment; and (iii) if the ferritin level is >2500 microg/l and liver iron concentation is >7 mg/g/dry weight, continuous subcutaneous (s.c.) or intravenous (i.v.) deferoxamine, or combined treatment with deferiprone and deferoxamine is advised. In case of heart failure, there is currently more solid documentation to support continuous s.c. or i.v. deferoxamine treatment than combined treatment with deferiprone and deferoxamine. However, more recent data in the literature suggest that the latter could be a satisfactory alternative. Finally, if iron chelation is required for sickle-cell disorders or myelodysplastic syndromes, the current data support the use of deferoxamine treatment.

Nuclear Stress Testing in Elderly Patients

Stress myocardial perfusion imaging (MPI) plays an important role in the diagnostic and prognostic assessment of coronary artery disease (CAD) in patients of all age groups who are undergoing assessment prior to non-cardiac surgery. MPI may utilise exercise treadmill or pharmacological stress testing. While MPI has been evaluated in a wide variety of patient subpopulations, there are very limited data on its prognostic value in the elderly population, particularly those >75 years of age, who are making up an ever increasing proportion of the patient population. Because of the higher prevalence and greater severity of CAD in older patients, the sensitivity of noninvasive MPI increases with age, whereas specificity tends to decline. In addition, maximal aerobic exercise capacity tends to decrease with age, making it common practice for elderly patients being assessed for CAD to undergo pharmacological MPI to evaluate their cardiovascular risk. In this article, we review the literature with respect to cardiac risk estimation in elderly patients undergoing MPI, particularly with respect to making prognostic assessments prior to undergoing surgery. Current data allow for the proper application of stress MPI in the elderly population. Use of MPI facilitates identification of the severity and extent of ischaemia as well as left ventricular dilatation and systolic function in elderly patients undergoing non-cardiac surgery.

Cardiotoxic Consequences of Anthracycline-Containing Therapy in Patients With Breast Cancer

In women, breast cancer is the second most common form of cancer and the leading cause of death caused by malignancy. The anthracycline antibiotics are potent anti-tumor agents used in a wide spectrum of malignancies. They are part of the gold standard adjuvant therapy for breast cancer and in metastatic disease they provide significant increases in response rate, time to disease progression, and overall survival. The addition of trastuzumab augments the effects of anthracycline-based therapy in both the adjuvant and metastatic settings. The successful use of anthracyclines is, however, restricted by the risk of developing life-threatening congestive heart failure. This risk increases exponentially with cumulative dose, and is further augmented by the addition of trastuzumab. Studies have reported that 10% to 26% of patients administered cumulative anthracycline doses above those recommended (> or =500 mg/m2 for doxorubicin and 1,000 mg/m2 for epirubicin) develop congestive heart failure, and that more than 50% of patients administered these doses will experience measurable functional impairment months to years after the end of therapy. The susceptibility of patients to anthracycline-induced cardiotoxicity varies widely, with a dramatic increase with advancing age. The onset of clinical and subclinical cardiac damage is delayed and occurs more than 3 months after the cessation of treatment, indicating a crucial time for functional impairment to occur and highlighting the ineffectiveness of monitoring left ventricular ejection fraction as an endpoint during anthracycline therapy. Possible future treatment options for managing anthracycline-induced cardiotoxicity include agents such as dexrazoxane that prevent oxygen-free radical generation. Further investigation is required into the use of angiotensin-converting enzyme inhibitors to redress cardiac damage and new methods of identifying patients at high risk of congestive heart failure before cardiac damage has occurred.

A review of the management of patients after percutaneous coronary intervention

The exponential increase in the numbers of percutaneous coronary interventions (PCIs) has led to many clinicians having to care for post-PCI patients. We review the management of early problems seen in post-PCI patients, such as vascular access site complications, contrast nephropathy, drug-induced thrombocytopaenia and chest pain. The management of possible restenosis and the use of stress testing are discussed. The complications from dual antiplatelet therapy are addressed. The prognosis of the post-PCI patient, the implications of co-existent heart failure and the newer technologies of implantable defibrillator and cardiac resynchronisation therapy are reviewed. We conclude by emphasising the importance of secondary prevention by risk factor modification as well as the communication between the clinician and the cardiologist.

Angina pectoris: evaluation in the office

Angina pectoris is a clinical manifestation of myocardial ischemia. Complete evaluation consists of a review of risk factors, a careful history, and, typically, a provocative test. Stress testing can be performed with exercise(treadmill, bicycle, or arm ergometry) or pharmacologic agents that increase cardiac work (dobutamine) or dilate the coronary vessels (adenosine or dipyridamole). Patients who have high-risk features found by clinical history or by stress testing should be referred for coronary angiography and possible revascularization. Comprehensive management of patients who have angina (with or without revascularization) includes smoking cessation,diet and weight control, vasculoprotective drugs (aspirin, statins, and possibly ACE inhibitors), and antianginal medications (nitrates, D-blockers, and calcium channel blockers). These strategies have led to an important reduction in morbidity and mortality over the past 2 decades, and the focus on implementing guidelines for patients who are currently undertreated is expected to improve outcomes further.

Use of Stress Testing Early After Coronary Artery Bypass Graft Surgery

The American College of Cardiology/American Heart Association guidelines for exercise testing do not take a position regarding the utility of routine stress testing after coronary artery bypass grafting (CABG). Our purposes were (1) to document the patterns of use of stress testing after CABG and (2) to establish whether the choice of stress testing strategy is associated with clinical characteristics of patients. The Routine versus Selective Exercise Treadmill Testing after Coronary Artery Bypass Graft Surgery (ROSETTA-CABG) Registry is a prospective multicenter study that examined the use of stress testing after CABG among 395 patients at 16 clinical centers in 6 countries. During the 12 months after CABG, 37% of patients underwent stress testing (range across centers 0% to 100%). Among patients who underwent stress testing, 24% had a clinical indication and 76% had it as a routine follow-up. A total of 65% of stress tests involved exercise treadmill testing alone, 17% involved stress nuclear perfusion imaging, 13% involved stress echocardiographic imaging, and 5% involved other types of stress tests, such as positron emission tomographic scans. The first stress test was performed at a median of 13 weeks after CABG, with 20% of patients having second tests at a median of 28 weeks and 6% having additional tests at a median of 34 weeks. Univariate and multivariate analyses demonstrated that the chief determinant of using routine stress testing was the clinical center. In conclusion, these results suggest that there is little consensus on the appropriate use of stress testing soon after CABG. Practice patterns vary widely; poorly diagnostic tests are used routinely; and the clinical center at which the procedure is performed, rather than the clinical characteristics of the patient, determines the use of stress testing after CABG.

Comparing cardiac ejection fraction estimation algorithms without a gold standard

RATIONALE AND OBJECTIVES

Imaging and estimation of left ventricular function have major diagnostic and prognostic importance in patients with coronary artery disease. It is vital that the method used to estimate cardiac ejection fraction (EF) allows the observer to best perform this task. To measure task-based performance, one must clearly define the task in question, the observer performing the task, and the patient population being imaged. In this report, the task is to accurately and precisely measure cardiac EF, and the observers are human-assisted computer algorithms that analyze the images and estimate cardiac EF. It is very difficult to measure the performance of an observer by using clinical data because estimation tasks typically lack a gold standard. A solution to this "no-gold-standard" problem recently was proposed, called regression without truth (RWT).

MATERIALS AND METHODS

Results of three different software packages used to analyze gated, cardiac, and nuclear medicine images, each of which uses a different algorithm to estimate a patient's cardiac EF, are compared. The three methods are the Emory method, Quantitative Gated Single-Photon Emission Computed Tomographic method, and the Wackers-Liu Circumferential Quantification method. The same set of images is used as input to each of the three algorithms. Data were analyzed from the three different algorithms by using RWT to determine which produces the best estimates of cardiac EF in terms of accuracy and precision.

RESULTS AND DISCUSSION

In performing this study, three different consistency checks were developed to ensure that the RWT method is working properly. The Emory method of estimating EF slightly outperformed the other two methods. In addition, the RWT method passed all three consistency checks, garnering confidence in the method and its application to clinical data.

Current understanding of coronary in-stent restenosis. Pathophysiology, clinical presentation, diagnostic work-up, and management

In-stent restenosis is the limiting entity following coronary stent implantation. It is associated with significant morbidity and cost and thus represents a major clinical and economical problem. Worldwide, approximately 250 000 in-stent restenotic lesions per year have to be dealt with. The pathophysiology of instent restenosis is multifactorial and comprises inflammation, smooth muscle cell migration and proliferation and extracellular matrix formation, all mediated by distinct molecular pathways. Instent restenosis has been recognised as very difficult to manage, with a repeat restenosis rate of 50% regardless of the mechanical angioplasty device used. Much more favourable results were reported for the adjunctive irradiation of the in-stent restenotic lesion, with a consistent reduction of the incidence of repeat in-stent restenosis by 50%. Data from the first clinical trials on drug-eluting stents for the treatment of in-stent restenosis have shown very much promise yielding this strategy likely to become the treatment of choice. This review outlines the histological and molecular findings of the pathophysiology, the epidemiology, the predictors and the diagnostic work-up of in-stent restenosis and puts emphasis on the various treatment options for its prevention and therapy.

Noninvasive Diagnosis of Restenosis by Transthoracic Doppler Echocardiography After Percutaneous Coronary Intervention: Comparison With Exercise Tl-SPECT

OBJECTIVE

Noninvasive methods that have the ability to accurately detect restenosis have been desired in the selection of patients requiring further angiographic evaluation. The present study sought to evaluate the diagnostic potential of transthoracic Doppler echocardiography (TTDE), a noninvasive method for evaluating coronary flow velocity reserve (CFVR), in detecting restenosis after percutaneous coronary intervention (PCI).

METHODS

We studied 107 consecutive patients 6 months after undergoing successful PCI on the left anterior descending coronary artery (LAD) lesions for relief of angina pectoris. The flow velocity in the distal LAD was measured by TTDE both at rest and during intravenous infusion of adenosine triphosphate. CFVR was calculated as the ratio of hyperemic to basal mean diastolic flow velocities. We defined a reversible perfusion defect in exercise Tl-201 single-photon emission computed tomography (SPECT) as restenosis. The CFVR measurements by TTDE were compared with the results of SPECT.

RESULTS

Complete TTDE data were acquired for 105 of the 107 study patients. A contrast agent was used to obtain adequate Doppler signals in 29 patients. Of the 105 patients, there were 18 patients with abnormal perfusion (group A) and 87 patients with normal perfusion (group B) in the LAD territories on Tl-201 SPECT. CFVR was greater in group B than in group A (1.7 +/- 0.5 vs. 3.7 +/- 0.8, P < 0.0001, respectively). There were 17 patients with CFVR < 2 and 88 patients with CFVR > or = 2. CFVR < 2 predicted restenosis determined by Tl-201 SPECT, with a sensitivity of 94% and a specificity of 100%.

CONCLUSIONS

Noninvasive measurement of CFVR by TTDE accurately reflects the physiological severity of coronary narrowing due to restenosis after PCI. This method has possibility of reducing the number of unnecessary coronary angiographies after PCI.

Selection of patients for myocardial perfusion scintigraphy based on fuzzy sets theory applied to clinical-epidemiological data and treadmill test results

Coronary artery disease (CAD) is a worldwide leading cause of death. The standard method for evaluating critical partial occlusions is coronary arteriography, a catheterization technique which is invasive, time consuming, and costly. There are noninvasive approaches for the early detection of CAD. The basis for the noninvasive diagnosis of CAD has been laid in a sequential analysis of the risk factors, and the results of the treadmill test and myocardial perfusion scintigraphy (MPS). Many investigators have demonstrated that the diagnostic applications of MPS are appropriate for patients who have an intermediate likelihood of disease. Although this information is useful, it is only partially utilized in clinical practice due to the difficulty to properly classify the patients. Since the seminal work of Lotfi Zadeh, fuzzy logic has been applied in numerous areas. In the present study, we proposed and tested a model to select patients for MPS based on fuzzy sets theory. A group of 1053 patients was used to develop the model and another group of 1045 patients was used to test it. Receiver operating characteristic curves were used to compare the performance of the fuzzy model against expert physician opinions, and showed that the performance of the fuzzy model was equal or superior to that of the physicians. Therefore, we conclude that the fuzzy model could be a useful tool to assist the general practitioner in the selection of patients for MPS.

Prediction of functional improvement of ischemic myocardium with (123I-BMIPP SPECT and 99mTc-tetrofosmin SPECT imaging: a study of patients with large acute myocardial infarction and receiving revascularization therapy

BACKGROUND

(18)F-fluorodeoxyglucose (FDG) positron-emission tomography (PET) is assumed to be the most useful method of evaluating the viability of the myocardium, but its use is limited by the need for a cyclotron. In the present study, the ability of a combination of (99m)Tc-tetrofosmin (TF) and (123)I-beta-methyliodophenyl pentadecanoic acid (BMIPP) single-photon emission computed tomography (SPECT), a combination of (18)F-FDG PET and (123)I-BMIPP SPECT, and a combination of (18)F-FDG PET and (99m)Tc-TF SPECT were compared to predict functional improvement of ischemic myocardium after a large acute myocardial infarction (AMI).

METHODS AND RESULTS

Ten patients with large AMI were studied by (99m)Tc-TF SPECT, (123)I-BMIPP SPECT and (18)F-FDG PET within 3 weeks. Six months later, (99m)Tc-TF imaging was performed. All patients underwent successful revascularization, and had no restenosis. Regional tracer uptake was scored using a 4-point scale in 20 segments of the SPECT and PET images. When the defect score of (123)I-BMIPP SPECT exceeded the defect score of (99m)Tc-TF SPECT or (18)F-FDG PET by 1 point or more, and when the defect score of (99m)Tc-TF SPECT exceeded the defect score of (18)F-FDG PET by 1 point or more, the segment was considered to show mismatching. When the defect score was the same in 2 tracers, the segment was considered to show matching. (99m)Tc-TF imaging at 3 weeks and 6 months used quantitative gated SPECT (QGS) to score wall motion using a 6-point scale (-1= dyskinesis, 0= akinesis, 1= severe hypokinesis, 2= moderate hypokinesis, 3= mild hypokinesis, and 4= normokinesis). The sensitivity of the combination of (123)I-BMIPP and (99m)Tc-TF imaging in predicting functional improvement was 61%, that of (18)F-FDG PET and (123)I-BMIPP SPECT was 94%, and that of (18)F-FDG PET and (99m)Tc-TF SPECT was 76%. The specificity of the combination of (123)I-BMIPP and (99m)Tc-TF imaging in predicting functional improvement was 83%, that of (18)F-FDG PET and (123)I-BMIPP SPECT was 40%, and that of (18)F-FDG PET and (99m)Tc-TF SPECT was 49%. The accuracy of the combination of (123)I-BMIPP and (99m)Tc-TF imaging in predicting functional improvement was 70%, that of (18)F-FDG PET and (123)I-BMIPP SPECT was 71%, and that of (18)F-FDG PET and (99m)Tc-TF SPECT was 63%.

CONCLUSION

The combination of (123)I-BMIPP and (99m)Tc-TF imaging is a practical modality for predicting the functional improvement of ischemic myocardium after a large AMI.

Portable type signal-averaged electrocardiography with dipyridamole: a new and convenient method to detect patients with coronary artery disease and ischemia

BACKGROUND

Whether or not patients with coronary artery disease (CAD) could be easily detected at the bedside using dipyridamole stress was investigated using a portable type signal-averaged electrocardiography (portable SAECG).

METHODS AND RESULTS

The standard 12-lead QRS wave SAECG was performed at the bedside before and after dipyridamole stress in 30 patients with angiographically significant stenotic lesions, who had positive myocardial ischemia in the dipyridamole-thallium myocardial perfusion imaging (CAD group), and 33 patients with no significant stenotic lesions, who had negative imaging (control group). The filtered QRS duration (fQRSd) before and after dipyridamole stress was determined by the vector magnitude method and the difference (DeltafQRSd) was obtained. Furthermore, the DeltafQRSd was obtained using the multiphasic oscillation method, as well at the same standard 12-lead, and the maximal value of changes in fQRSd (MAX DeltafQRSd) between the 12 leads was determined. The DeltafQRSd was similar between 2 groups (p = 0.11). The MAX DeltafQRSd associated was significantly greater in the CAD group (p < 0.0001). When a cut-off value of MAX DeltafQRSd > or = 5 ms was used for the detection of CAD, the sensitivity and specificity were 97 and 94%, respectively.

CONCLUSION

The portable dipyridamole-stress SAECG easily detect CAD and myocardial ischemia at the bedside.

Myocardial viability assessment in patients with highly impaired left ventricular function: comparison of delayed enhancement, dobutamine stress MRI, end-diastolic wall thickness, and TI201-SPECT with functional recovery after revascularization

This study compared different magnetic resonance imaging (MRI) methods with Tl(201) single photon emission computerized tomography (SPECT) and the "gold standard" for viability assessment, functional recovery after coronary artery bypass grafting (CABG). Twenty patients (64+/-7.3 years) with severely impaired left ventricular function (ejection fraction [EF] 28.6+/-8.7%) underwent MRI and SPECT before and 6 months after CABG. Wall-motion abnormalities were assessed by stress cine MRI using low-dose dobutamine. A segment with a nonreversible defect in Tl(201)-SPECT and a delayed enhancement (DE) in an area >50% of the entire segment, as well as an end-diastolic wall thickness <6 mm, was defined as nonviable. The mean postoperative EF (n=20) improved slightly from 28.6+/-8.7% to 32.2+/-12.4% (not significant). Using the Tl(201)-SPECT as the reference method, end-diastolic wall thickness, MRI-DE, and stress MRI showed high sensitivity of 94%, 93%, and 84%, respectively, but low specificities. Using the recovery of contractile function 6 months after CABG as the gold standard, MRI-DE showed an even higher sensitivity of 99%, end-diastolic wall thickness 96%, stress MRI 88%, and Tl(201)-SPECT 86%. MRI-DE showed advantages compared with the widely used Tl(201)-SPECT and all other MRI methods for predicting myocardial recovery after CABG.

QRS score versus ST-segment changes in patients undergoing Tl-201 scintigraphy using dipyridamole infusion

BACKGROUND

ST-segment changes after dipyridamole infusion followed by handgrip isometric stress lack diagnostic value, because of the low sensitivity for the detection of coronary artery disease (CAD). In addition, an abnormal QRS score during exercise had a greater diagnostic ability than ST-segment changes to detect CAD. This study was undertaken to compare QRS score values with ST-segment changes during thallium 201 scintigraphy via dipyridamole infusion.

METHODS AND RESULTS

In this study 128 patients (101 men and 27 women), aged 53 to 72 years (mean, 59 +/- 8 years), underwent Tl-201 scintigraphy after dipyridamole infusion and handgrip isometric stress, as well as coronary angiography. QRS score values and ST-segment changes after dipyridamole infusion and handgrip isometric stress were also estimated. CAD was detected in 96 patients (75%), whereas normal coronary arteries were found in 32 (25%). According to scintigraphic data, 48 patients (37%) had no reversible perfusion defects whereas 80 (63%) had at least 1 reversible perfusion defect. Sensitivities for an abnormal QRS score and ST-segment deviation were 68% versus 18% ( P < .01) for detection of CAD and 75% versus 19% for detection of myocardial ischemia ( P < .01), respectively. Similar specificities were found ( P = not significant).

CONCLUSIONS

An abnormal QRS score significantly improves the low sensitivity of ST-segment changes for the detection of myocardial ischemia and CAD by use of Tl-201 scintigraphy with dipyridamole infusion and handgrip isometric stress.