Prognostic significance of the location of wall motion abnormalities during exercise echocardiography

The impacts of percutaneous coronary intervention to treat chronic total occlusion of right coronary artery on the 5-year prognosis: A single-centered retrospective study

BACKGROUND

Chronic total occlusions (CTO) occur in about 20% of patients referred for coronary angiography, and right coronary artery (RCA) CTO has been reported in 38-50% of the entire CTO population. Limited data on angiographic and procedural characteristics of RCA-CTO and the risk of adverse cardiac events asks for a detailed study.

METHODS

From 2010 to 2013, patients with attempted revascularization of at least one CTO lesion were included and followed up to 5 years after PCI. Eligible patients are assigned to RCA-CTO and non-RCA-CTO groups based on their target vessels. The primary endpoint was major adverse cardiovascular events (MACEs; a composite of all-cause death, myocardial infarction (MI) or rehospitalization for heart failure), and secondary endpoints were cardiac death, target lesion revascularization (TLR) and target vessel revascularization (TVR).

RESULTS

The present study included 2659 eligible patients, among which 1285 patients were assigned to the RCA-CTO group, whereas 1374 patients were assigned to the non-RCA-CTO group. Lesions in RCA had longer lesion length, higher J-CTO score, higher rates of severe vessel tortuosity, a higher percentage of Rentrop grade 2-3, and more likely to be re-try lesion than those in LAD or LCX (all P < 0.01). CTO lesions in RCA reached less successful recanalization and post-procedural TIMI 3 flow (all <0.01). Multivariate Cox analysis revealed that RCA-CTO was not associated with primary outcome MACEs. Besides MACEs, RCA-CTO was also not associated with cardiac death, but was significantly associated with TLR and TVR (adjusted HR: 1.37 [95% CI:1.07-1.76], P = 0.01; adjusted HR: 1.43 [95% CI:1.13-1.82], P = 0.003).

CONCLUSION

RCA-CTO lesions, which had more complex angiographic features, independently contributed to TLR and TVR but not to MACEs or cardiac death in the 5 years of follow-up.

Development of artificial intelligence-based slow-motion echocardiography and clinical usefulness for evaluating regional wall motion abnormalities

The diagnostic accuracy of exercise stress echocardiography (ESE) for myocardial ischemia requires improvement, given that it currently depends on the physicians' experience and image quality. To address this issue, we aimed to develop artificial intelligence (AI)-based slow-motion echocardiography using inter-image interpolation. The clinical usefulness of this method was evaluated for detecting regional wall-motion abnormalities (RWMAs). In this study, an AI-based echocardiographic image-interpolation pipeline was developed using optical flow calculation and prediction for in-between images. The accuracy for detecting RWMAs and image readability among 25 patients with RWMA and 25 healthy volunteers was compared between four cardiologists using slow-motion and conventional ESE. Slow-motion echocardiography was successfully developed for arbitrary time-steps (e.g., 0.125×, and 0.5×) using 1,334 videos. The RWMA detection accuracy showed a numerical improvement, but it was not statistically significant (87.5% in slow-motion echocardiography vs. 81.0% in conventional ESE; odds ratio: 1.43 [95% CI: 0.78-2.62], p = 0.25). Interreader agreement analysis (Fleiss's Kappa) for detecting RWMAs among the four cardiologists were 0.66 (95%CI: 0.55-0.77) for slow-motion ESE and 0.53 (95%CI: 0.42-0.65) for conventional ESE. Additionally, subjective evaluations of image readability using a four-point scale showed a significant improvement for slow-motion echocardiography (2.11 ± 0.73 vs. 1.70 ± 0.78, p < 0.001).In conclusion, we successfully developed slow-motion echocardiography using in-between echocardiographic image interpolation. Although the accuracy for detecting RWMAs did not show a significant improvement with this method, we observed enhanced image readability and interreader agreement. This AI-based approach holds promise in supporting physicians' evaluations.

Percutaneous coronary intervention for chronic total occlusion of the left circumflex branch in mirror dextrocardia: a case report

BACKGROUND

Mirror dextrocardia (MDC) is a condition in which the heart is located in a mirror-image position on the right side of the chest compared to the normal position in individuals with physiological variations. Patients with MDC and chronic total occlusion (CTO) of the left circumflex branch (LCX) are extremely rare in clinical practice. The treatment of MDC-CTO-LCX differs significantly from patients without mirror dextrocardia and the same condition in terms of instrument selection and procedural techniques. In this article, we report a successful case of interventional treatment in a patient with MDC-CTO-LCX. We summarize the anatomical and electrocardiographic variations in patients with MDC-CTO-LCX, and discuss the selection of interventional instruments and techniques that can be useful for interventionists as well as the diagnostic and therapeutic considerations that can be helpful for clinical physicians.

CASE PRESENTATION

A male Han Chinese patient, 51, was admitted, presenting recurrent chest pain for a year and recent onset of exertional fatigue over the past week.He reported episodes of chest pain following physical activities over the past year, lasting between 5 and 20 min.Despite these symptoms, the patient did not seek immediate medical attention, and the occurrence of his chest pain has progressively lessened within the year.A week prior, the patient developed exertional dyspnea after brief walks, though without any episodes of nocturnal paroxysmal dyspnea.Upon arrival at our hospital for evaluation, he was initially diagnosed with chronic coronary syndrome, previous inferior myocardial infarction, atrial arrhythmia, and classified under the New York Heart Association functional class III.Following his admission, a chest X-ray and coronary angiography were conducted.The results indicated mirror dextrocardia and total occlusion of the left circumflex branch. Percutaneous coronary intervention (PCI) was performed on the left circumflex branch. Subsequent angiography demonstrated optimal stent positioning without evidence of hematoma or dissection.Following the procedure, the patient's symptoms of chest pain and exertional dyspnea were resolved, which led to his subsequent discharge.A follow-up electrocardiogram, 10 months post-procedure, displayed a slow and regular atrial rhythm.

CONCLUSIONS

The incidence of dextrocardia is very low, and it may appear normal on an electrocardiogram; however, careful diagnosis is required when there is an abnormal direction of the P wave in limb leads. During the operation for chronic occlusive lesions of the right-sided coronary artery, the anomalous anatomical structure necessitates specific requirements for instrument selection and operative techniques. After revascularization of chronic occlusive vessels in dextrocardia, routine electrocardiographic examination may show false normalization, requiring caution in interpretation.

Pattern and Prognostic Impact of Regional Wall Motion Abnormalities in 255 697 Men and 236 641 Women Investigated with Echocardiography

Background Regional wall motion abnormalities (WMAs) after myocardial infarction are associated with adverse remodeling and increased mortality in the short to medium term. Their long-term prognostic impact is less well understood. Methods and Results Via the National Echo Database of Australia (2000-2019), we identified normal wall motion versus WMA for each left ventricular wall among 492 338 individuals aged 61.9±17.9 years. The wall motion score index was also calculated. We then examined actual 1- and 5-year mortality, plus adjusted risk of long-term mortality according to WMA status. Overall, 39 346/255 697 men (15.4%) and 17 834/236 641 women (7.5%) had a WMA. The likelihood of a WMA was associated with increasing age and greater systolic/diastolic dysfunction. A defect in the inferior versus anterior wall was the most and least common WMA in men (8.0% and 2.5%) and women (3.3% and 1.1%), respectively. Any WMA increased 5-year mortality from 17.5% to 29.7% in men and from 14.9% to 30.8% in women. Known myocardial infarction (hazard ratio [HR], 0.86 [95% CI, 0.80-0.93]) or revascularization (HR, 0.87 [95% CI, 0.82-0.92]) was independently associated with a better prognosis, whereas men (1.22-fold increase) and those with greater systolic/diastolic dysfunction had a worse prognosis. Among those with any WMA, apical (HR, 1.08 [95% CI, 1.02-1.13]) or inferior (HR, 1.09 [95% CI, 1.04-1.15]) akinesis, dyskinesis or aneurysm, or a wall motion score index >3.0 conveyed the worst prognosis. Conclusions In a large real-world clinical cohort, twice as many men as women have a WMA, with inferior WMA the most common. Any WMA confers a poor prognosis, especially inferoapical akinesis/dyskinesis/aneurysm.

Patients with Moderate Non-Culprit Coronary Lesions of Recent Acute Coronary Syndrome

Fractional flow reserve (FFR) measurement was compared to dobutamine stress echocardiography (DSE) instable angina (SA) with stable coronary lesion (s) (SCL (s) ) in a few trials; however, similar comparisons in patients with acute coronary syndrome (ACS) with non-culprit lesion (s) (NCL (s) ) are lacking. Our objectives were to prospectively evaluate the diagnostic performance of FFR with two different cutoff values (< 0.80 and < 0.75) relative to DSE in moderate (30%-70% diameter stenosis) NCLs (ACS group) and to compare these observations with those measured in SCLs (SA group). One hundred seventy-five consecutive patients with SA (n = 86) and ACS (n = 89) with 225 coronary lesions (109 SCLs and 116 NCLs) were enrolled. In contrast to the ACS cohort in SA patients, normal DSE was associated with higher FFR values compared to those with abnormal DSE (P = 0.051 versus P = 0.006). In addition, in the SA group, a significant correlation was observed between DSE (regional wall motion score index at peak stress) and FFR (r = -0.290; P = 0.002), whereas a similar association was absent (r = -0.029; P = 0.760) among ACS patients. In the SA group, decreasing the FFR cutoff value (< 0.80 versus < 0.75) improved the concordance of FFR with DSE (70.6% versus 81.7%) without altering its discriminatory power (area under the curve; 0.68 versus 0.63; P = 0.369), whereas in the ACS group, concordance remained similar (69.0% versus 71.6%) and discriminatory power decreased (0.62 versus 0.51; P = 0.049), respectively. In conclusion, lesion-specific FFR assessment may have different relevance in patients with moderate NCLs than in patients with SCLs.

Real-world performance and accuracy of stress echocardiography: the EVAREST observational multi-centre study

Aims

Stress echocardiography is widely used to identify obstructive coronary artery disease (CAD). High accuracy is reported in expert hands but is dependent on operator training and image quality. The EVAREST study provides UK-wide data to evaluate real-world performance and accuracy of stress echocardiography.

Methods and results

Participants undergoing stress echocardiography for CAD were recruited from 31 hospitals. Participants were followed up through health records which underwent expert adjudication. Cardiac outcome was defined as anatomically or functionally significant stenosis on angiography, revascularization, medical management of ischaemia, acute coronary syndrome, or cardiac-related death within 6 months. A total of 5131 patients (55% male) participated with a median age of 65 years (interquartile range 57–74). 72.9% of studies used dobutamine and 68.5% were contrast studies. Inducible ischaemia was present in 19.3% of scans. Sensitivity and specificity for prediction of a cardiac outcome were 95.4% and 96.0%, respectively, with an accuracy of 95.9%. Sub-group analysis revealed high levels of predictive accuracy across a wide range of patient and protocol sub-groups, with the presence of a resting regional wall motion abnormalitiy significantly reducing the performance of both dobutamine (P < 0.01) and exercise (P < 0.05) stress echocardiography. Overall accuracy remained consistently high across all participating hospitals.

Conclusion

Stress echocardiography has high accuracy across UK-based hospitals and thus indicates stress echocardiography is being delivered effectively in real-world practice, reinforcing its role as a first-line investigation in the assessment of patients with stable chest pain.

Percutaneous Coronary Intervention for Chronic Total Occlusion in Single Coronary Arteries

We retrospectively compared the results of percutaneous coronary intervention (PCI) and optimal medical therapy (OMT) for chronic total occlusion (CTO) in single coronary arteries to determine whether outcomes depend on the artery involved. From January 2004 through November 2015, a total of 731 patients were treated at our center for CTO in the left anterior descending coronary artery (LAD) (234 patients, 32%), left circumflex coronary artery (LCx) (184, 25.2%), or right coronary artery (RCA) (313, 42.8%). We further classified patients by treatment (PCI or OMT) and compared the cumulative incidence of major adverse cardiac events (MACE) and the composite of total death or myocardial infarction, as well as change in left ventricular ejection fraction from baseline. The 5-year cumulative incidence of MACE was similar between the treatment groups regardless of target vessel. The 5-year cumulative incidence of the composite of total death or myocardial infarction was significantly lower after PCI than after OMT or failed PCI in the LCx (2.6% vs 11.5%; P=0.020; log-rank) and RCA (5.8% vs 17.2%; P=0.002) groups, but not in the LAD group. Cox proportional hazards regression analysis indicated that PCI independently predicted a lower incidence of the composite of total death or myocardial infarction in the LCx group (hazard ratio [HR]=0.184; 95% CI, 0.0035-0.972; P=0.046) and the RCA group (HR=0.316; 95% CI, 0.119-0.839; P=0.021). The artery involved does not appear to affect clinical outcomes of successful PCI for single-vessel CTO. Further investigation in a randomized clinical trial is warranted.

Cardiac and sudden death after chronic total occlusion percutaneous coronary intervention: Prognostic role of the target vessel

BACKGROUND

The role of the target vessel in percutaneous revascularization of chronic total occlusion (CTO) is unclear.

OBJECTIVE

We sought to assess the long-term results of percutaneous coronary intervention (PCI) for CTO lesions in each coronary artery and to investigate the impact of successful revascularization and previous myocardial infarction (MI) in the territory of the target vessel.

METHODS AND RESULTS

Cohort observational study on 1,124 patients who have undergone CTO PCI attempt: 371 on left anterior descending artery (LAD), 485 right coronary artery, and 268 left circumflex. Patients were further stratified by successfully revascularized and not-revascularized CTO (CTO-NR). Vessels affected by a previous MI were defined as infarct-related artery (IRA). The primary endpoint was cardiac death; the secondary endpoint was the combined rate of sudden cardiac-death and sustained ventricular-arrhythmias (SCD/SVAs). Propensity score-matching was performed to evaluate LAD versus NON-LAD CTO. Up to 12-year follow-up, the clinical benefit associated with successful PCI was consistent across the three groups. CTO-NR had the greatest association with cardiac death and SCD/SVAs in each coronary artery and in IRA-CTO patients.

CONCLUSIONS

Unsuccessful percutaneous CTO revascularization was associated with lower cardiac survival and freedom from SCD/SVAs, irrespective of the vessel treated. This result was mainly driven by patients with an IRA CTO.

Clinical Outcomes in Chronic Total Occlusion Revascularization Versus No Chronic Total Occlusion Revascularization: Variability by Target Vessel

We aimed to investigate the impact of target vessel on clinical outcomes in chronic total occlusion (CTO) revascularization versus no CTO revascularization. This multicenter, retrospective, cohort study involves patients with ≥1 CTO. After classification based on different CTO target vessels or multiple CTOs, patients were further categorized as the CTO revascularization group and the no CTO revascularization group based on treatment received. The primary outcome was a composite of death, myocardial infarction, stroke, repeated revascularization, and hospital admission due to ischemic symptoms. From August 2016 to August 2017, 1712 eligible patients were consecutively enrolled. Chronic total occlusion revascularization was associated with lower risk of 1-year major adverse cardiovascular and cerebrovascular events (MACCEs; adjusted hazard ratio [HR]: 0.36; 95% CI: 0.20-0.67; P = .001) compared with no CTO revascularization in left anterior descending (LAD) CTO patients. The benefit of CTO revascularization was not evident among those with left circumflex (LCX; adjusted HR: 0.51; 95% CI: 0.23-1.10; P = .087), right coronary artery (RCA; adjusted HR: 1.17; 95% CI: 0.59-2.33; P = .648), and multiple CTOs (adjusted HR: 1.00; 95% CI: 0.41-2.44; P = .994). Revascularization for LAD CTO, but not LCX, RCA, or multiple CTOs, was associated with lower risk of 1-year MACCEs compared with no CTO revascularization.

Implications of Abnormal Exercise Electrocardiography With Normal Stress Echocardiography

IMPORTANCE

Patients with abnormal (positive) exercise electrocardiography, but normal stress echocardiography (+ECG/-Echo) are commonly encountered in clinical practice; however, the prognostic significance of this discordant result is unclear.

OBJECTIVE

To determine whether patients with +ECG/-Echo have a higher rate of adverse clinical events and a poorer prognosis than patients with negative exercise ECG and normal stress Echo imaging (-ECG/-Echo).

DESIGN, SETTING, AND PARTICIPANTS

Between January 1, 2000, and February 28, 2014, a total of 47 944 consecutive patients without known coronary artery disease who underwent exercise stress Echo at Duke University Medical Center were evaluated for inclusion in this observational cohort study. Data analysis was conducted from January 1, 2000, to December 31, 2016.

INTERVENTIONS/EXPOSURES

Patients were categorized as having -ECG/-Echo, +ECG/-Echo, or +Echo (-ECG/+Echo and +ECG/+Echo).

MAIN OUTCOMES AND MEASURES

The primary outcome was a composite end point of death, myocardial infarction, hospitalization for unstable angina, and coronary revascularization. Secondary outcomes included individual adverse events and downstream testing.

RESULTS

After excluding submaximal tests and nondiagnostic ECG or stress imaging results, 15 077 patients (mean [SD] age, 52 [13] years; 6228 [41.3%] men) were classified by stress test results. Of these, 12 893 patients (85.5%) had -ECG/-Echo, 1286 patients (8.5%) had +ECG/-Echo, and 898 patients (6.0%) had +Echo. Through a median follow-up of 7.3 (interquartile range, 4.4-10.0) years, the composite end point occurred in 794 patients with -ECG/-Echo (8.5%), 142 patients with +ECG/-Echo (14.6%), and 297 patients with +Echo (37.4%). Death occurred in 425 patients with -ECG/-Echo (4.8%), 50 patients with +ECG/-Echo (5.9%), and 70 patients with +Echo (11.2%). Myocardial infarction occurred in 195 patients with -ECG/-Echo (2.2%), 31 patients with +ECG/-Echo (3.6%), and 59 patients with +Echo (8.7%). The addition of stress ECG findings to clinical and exercise data yielded incremental prognostic value. Patients with -ECG/-Echo imaging results had the least downstream testing (2.3%), followed by +ECG/-Echo (12.8%), and +Echo (33.6%) (P < .001).

CONCLUSIONS AND RELEVANCE

The presence of +ECG results with normal stress Echo imaging may identify a population of patients who are at slightly increased risk for adverse cardiac events, which was not previously recognized. Further study is needed to determine whether these patients will benefit from intensification of medical management.

Invasive coronary angiography findings across the CAD-RADS classification spectrum

The recently introduced coronary artery disease reporting and data system (CAD-RADS) evaluated by computed tomography and based on stenosis severity, might not adequately reflect the complexity of CAD. We explored the relationship between CAD-RADS and the spatial distribution, burden, and complexity of lesions by invasive coronary angiography (ICA). Stable patients who underwent coronary computed tomography angiography (CCTA) and ICA comprised the study population. Patients were classified according to the CAD-RADS: 0, No plaque; 1, 1-24% stenosis; 2, 25-49%; 3, 50-69%; 4A, 70-99%; 4B, left main stenosis or 3-vessel obstructive disease; and 5, total occlusion. Based on ICA findings, we calculated the SYNTAX score and the CAD extension index. Ninety-one patients were included, with a mean age of 61.4 ± 10.5 years (74% male). We found significant relationships between CAD-RADS and both the SYNTAX score (p < 0.0001) and the CAD extension index (p < 0.0001), although the complexity of coronary anatomy differed among patients with CAD-RADS ≥ 4A. Among patients with CAD-RADS < 4, the mean segment involvement score (SIS) was 8.4 ± 4.0, 52% of them with a SIS > 5. Of the 30 patients with CAD-RADS 5, 9 (30%) affected distal segments or secondary branches, and 9 (30%) had concomitant severe non-extensive disease at ICA. Regarding the spatial distribution of the non-occluded most severe lesions, 27 (44%) comprised distal segments or secondary branches. In the present study including a high-risk population, we identified diverse coronary anatomy complexity scenarios and relevant differences in spatial distribution sharing the same CAD-RADS classification.

[The Clinical use of Stress Echocardiography in Ischemic Heart Disease Cardiovascular Ultrasound (2017)15:7. Translation authors: Arystan A.Zh., Fettser D.V.]

Stress echocardiography is an established technique for the assessment of extent and severity of coronary artery disease. The combination of echocardiography with a physical, pharmacological or electrical stress allows detecting myocardial ischemia with an excellent accuracy. A transient worsening of regional function during stress is the hallmark of inducible ischemia. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging or magnetic resonance, but at a substantially lower cost, without environmental impact, and with no biohazards for the patient and the physician. The evidence on its clinical impact has been collected over 35 years, based on solid experimental, pathophysiological, technological and clinical foundations. There is the need to implement the combination of wall motion and coronary flow reserve, assessed in the left anterior descending artery, into a single test. The improvement of technology and in imaging quality will make this approach more and more feasible. The future issues in stress echo will be the possibility of obtaining quantitative information translating the current qualitative assessment of regional wall motion into a number. The next challenge for stress echocardiography is to overcome its main weaknesses: dependence on operator expertise, the lack of outcome data (a widespread problem in clinical imaging) to document the improvement of patient outcomes. This paper summarizes the main indications for the clinical applications of stress echocardiography to ischemic heart disease.

Impact of Chronic Total Coronary Occlusion Location on Long-term Survival After Percutaneous Coronary Intervention

INTRODUCTION AND OBJECTIVES

Limited data are available on the clinical outcomes of optimal medical therapy (OMT) compared with revascularization by percutaneous coronary intervention (PCI) in patients with chronic total coronary occlusion (CTO) of the proximal or middle left anterior descending artery (pmLAD). Therefore, the objective of this study was to compare the long-term outcomes of patients with pmLAD CTO who were treated with a PCI strategy with those of patients treated with an OMT strategy.

METHODS

Between March 2003 and February 2012, 2024 patients with CTO were enrolled in a single-center registry. Among this patient group, we excluded CTO patients who underwent coronary artery bypass grafting. After the exclusion, a total of 1547 patients remained. They were stratified according to classification of coronary segments (pmLAD or non-pmLAD CTO) and the initial treatment strategy (OMT or PCI). Propensity score matching was performed. The primary outcome was cardiac death.

RESULTS

The median follow-up was 45.9 (interquartile range, 22.9-71.1) months. After propensity score matching, the incidence of cardiac death (HR, 0.54; 95%C, 0.31-0.94, P=.029) was significantly lower in the PCI with pmLAD CTO group than in the OMT group. In contrast, no significant difference was found in the rate of cardiac death between the PCI and OMT groups with non-pmLAD CTO (HR, 0.62; 95%CI, 0.27-1.42, P=.26).

CONCLUSIONS

As an initial treatment strategy, PCI of pmLAD CTO, but not PCI of non-pmLAD, is associated with improved long-term survival.

Cardiac Imaging in the Diagnosis of Coronary Artery Disease

Coronary artery disease (CAD) continues to be a leading cause of morbidity and mortality worldwide. Although invasive coronary angiography has previously been the gold standard in establishing the diagnosis of CAD, there is a growing shift to more appropriately use the cardiac catheterization laboratory to perform interventional procedures once a diagnosis of CAD has been established by noninvasive imaging modalities rather than using it primarily as a diagnostic facility to confirm or refute CAD. With ongoing technological advancements, noninvasive imaging plays a pre-eminent role in not only diagnosing CAD but also informing the choice of appropriate therapies, establishing prognosis, all while containing costs and providing value-based care. Multiple imaging modalities are available to evaluate patients suspected of having coronary ischemia, such as stress electrocardiography, stress echocardiography, single-photon emission computed tomography myocardial perfusion imaging, positron emission tomography, coronary computed tomography (CT) angiography, and magnetic resonance imaging. These imaging modalities can variably provide functional and anatomical delineation of coronary stenoses and help guide appropriate therapy. This review will discuss their advantages and limitations and their usage in the diagnostic pathway for patients with CAD. We also discuss newer technologies such as CT fractional flow reserve, CT angiography with perfusion, whole-heart coronary magnetic resonance angiography with perfusion, which can provide both anatomical as well as functional information in the same test, thus obviating the need for multiple diagnostic tests to obtain a comprehensive assessment of both, plaque burden and downstream ischemia. Recognizing that clinicians have a multitude of tests to choose from, we provide an underpinning of the principles of ischemia detection by these various modalities, focusing on anatomy vs physiology, the database justifying their use, their prognostic capabilities and lastly, their appropriate and judicious use in this era of patient-centered, cost-effective imaging.

The clinical use of stress echocardiography in ischemic heart disease

Stress echocardiography is an established technique for the assessment of extent and severity of coronary artery disease. The combination of echocardiography with a physical, pharmacological or electrical stress allows to detect myocardial ischemia with an excellent accuracy. A transient worsening of regional function during stress is the hallmark of inducible ischemia. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging or magnetic resonance, but at a substantially lower cost, without environmental impact, and with no biohazards for the patient and the physician.

The evidence on its clinical impact has been collected over 35 years, based on solid experimental, pathophysiological, technological and clinical foundations. There is the need to implement the combination of wall motion and coronary flow reserve, assessed in the left anterior descending artery, into a single test. The improvement of technology and in imaging quality will make this approach more and more feasible. The future issues in stress echo will be the possibility of obtaining quantitative information translating the current qualitative assessment of regional wall motion into a number. The next challenge for stress echocardiography is to overcome its main weaknesses: dependance on operator expertise, the lack of outcome data (a widesperad problem in clinical imaging) to document the improvement of patient outcomes. This paper summarizes the main indications for the clinical applications of stress echocardiography to ischemic heart disease.

Prognostic impact of location and extent of vessel-related ischemia at myocardial perfusion scintigraphy in patients with or at risk for coronary artery disease

BACKGROUND

Myocardial perfusion scintigraphy (MPS) has an established diagnostic and prognostic role in patients with or at risk for coronary artery disease, with ischemia severity and extent having already been identified as key predictors. Whether this is affected by the location of myocardial ischemia is uncertain. We aimed at comparing the prognostic outlook of patients undergoing MPS according to the site of ischemia.

METHODS

Our institutional database was queried for subjects undergoing MPS, without myocardial necrosis or recent revascularization. We focused on the prognostic impact of location of vessel-related ischemia (VRI) at MPS, distinguishing four mutually exclusive groups: single-VRI involving left anterior descending (LAD), single-VRI not involving LAD, multi-VRI involving LAD, and multi-VRI not involving LAD. The primary outcome was the long-term (>1 year) rate of death or myocardial infarction (D/MI).

RESULTS

A total of 13,254 patients were included. Moderate or severe VRI occurred in 2,627 (20%) patients. Clinical outcomes were significantly different among the groups of patients with moderate or severe VRI, including death, cardiac death, non-fatal myocardial infarction or their composites (overall P < .001). Specifically, and excluding subjects undergoing revascularization as first follow-up event, D/MI occurred in 8.4% of patients with single-VRI involving LAD, 5.5% of subjects with single-VRI not involving LAD, 16.5% of those with multi-VRI involving LAD, and 7.3% of patients with multi-VRI not involving LAD (overall P < .001). Even at incremental multivariable Cox proportional analysis, hierarchical VRI was independently associated with an increased risk of D/MI [hazard ratio = 1.17 (1.04-1.08) for each class increment, P = .010].

CONCLUSIONS

Location and extent of myocardial ischemia at MPS according to the VRI concept have a hierarchical predictive impact, with multi-VRI involving LAD being significantly and independently more prognostically ominous than other types of VRI.

Cardiac CT vs. Stress Testing in Patients with Suspected Coronary Artery Disease: Review and Expert Recommendations

Diagnosis and management of coronary artery disease represent a major challenge to our health care systems affecting millions of patients each year. Until recently, the diagnosis of coronary artery disease could be conclusively determined only by invasive coronary angiography. To avoid risks from cardiac catheterization, many healthcare systems relied on stress testing as gatekeeper for coronary angiography. Advancements in cardiac computed tomography angiography technology now allows to noninvasively visualize coronary artery disease, challenging the role of stress testing as the default noninvasive imaging tool for evaluating patients with chest pain. In this review, we summarize current data on the clinical utility of cardiac computed tomography and stress testing in stable patients with suspected coronary artery disease.

Comparative definitions for moderate-severe ischemia in stress nuclear, echocardiography, and magnetic resonance imaging

The lack of standardized reporting of the magnitude of ischemia on noninvasive imaging contributes to variability in translating the severity of ischemia across stress imaging modalities. We identified the risk of coronary artery disease (CAD) death or myocardial infarction (MI) associated with ≥10% ischemic myocardium on stress nuclear imaging as the risk threshold for stress echocardiography and cardiac magnetic resonance. A narrative review revealed that ≥10% ischemic myocardium on stress nuclear imaging was associated with a median rate of CAD death or MI of 4.9%/year (interquartile range: 3.75% to 5.3%). For stress echocardiography, ≥3 newly dysfunctional segments portend a median rate of CAD death or MI of 4.5%/year (interquartile range: 3.8% to 5.9%). Although imprecisely delineated, moderate-severe ischemia on cardiac magnetic resonance may be indicated by ≥4 of 32 stress perfusion defects or ≥3 dobutamine-induced dysfunctional segments. Risk-based thresholds can define equivalent amounts of ischemia across the stress imaging modalities, which will help to translate a common understanding of patient risk on which to guide subsequent management decisions.

Physical Stress Echocardiography: Prediction of Mortality and Cardiac Events in Patients with Exercise Test showing Ischemia

Background

Studies have demonstrated the diagnostic accuracy and prognostic value of physical stress echocardiography in coronary artery disease. However, the prediction of mortality and major cardiac events in patients with exercise test positive for myocardial ischemia is limited.

Objective

To evaluate the effectiveness of physical stress echocardiography in the prediction of mortality and major cardiac events in patients with exercise test positive for myocardial ischemia.

Methods

This is a retrospective cohort in which 866 consecutive patients with exercise test positive for myocardial ischemia, and who underwent physical stress echocardiography were studied. Patients were divided into two groups: with physical stress echocardiography negative (G1) or positive (G2) for myocardial ischemia. The endpoints analyzed were all‑cause mortality and major cardiac events, defined as cardiac death and non-fatal acute myocardial infarction.

Results

G2 comprised 205 patients (23.7%). During the mean 85.6 ± 15.0-month follow-up, there were 26 deaths, of which six were cardiac deaths, and 25 non-fatal myocardial infarction cases. The independent predictors of mortality were: age, diabetes mellitus, and positive physical stress echocardiography (hazard ratio: 2.69; 95% confidence interval: 1.20 – 6.01; p = 0.016). The independent predictors of major cardiac events were: age, previous coronary artery disease, positive physical stress echocardiography (hazard ratio: 2.75; 95% confidence interval: 1.15 – 6.53; p = 0.022) and absence of a 10% increase in ejection fraction. All-cause mortality and the incidence of major cardiac events were significantly higher in G2 (p < 0. 001 and p = 0.001, respectively).

Conclusion

Physical stress echocardiography provides additional prognostic information in patients with exercise test positive for myocardial ischemia.

Does location matter? Prognostic value of single-photon emission computed tomography myocardial perfusion imaging by vascular territory

BACKGROUND

The location of a myocardial perfusion abnormality frequently affects clinical decision making, especially if the left anterior descending artery (LAD) territory is involved. The purpose of this study was to determine whether the location of abnormalities on single-photon emission computed tomography (SPECT) imaging affects outcomes.

METHODS

We retrospectively analyzed 21,294 consecutive patients with known or suspected coronary artery disease who underwent exercise or pharmacological stress SPECT over a 10-year period. Using the ASNC 17-segment model, 2 observers interpreted images with regards to defect severity, size, and reversibility. The summed stress score (SSS) was used in relation to vascular territories [LAD, right coronary artery (RCA), and left circumflex artery (LCx)]. All patients were followed over a mean period of 2.5 ± 2 years for cardiac events (cardiac death or non-fatal myocardial infarction).

RESULTS

Of the enrolled patients, 5,676 had single-vessel territory defects with a mean SSS of 4.3 ± 2.8. Cardiac event-free survival curves revealed no significant difference between the 3 locations (LAD, RCA, and LCx) (P = .235). When compared by mild (2-3), moderate (4-8), or severe (>8) SSS, outcomes between the 3 groups were again similar. There were 2,907 patients with two-vessel territory defects with a mean SSS of 10.8. Outcomes were similar between the following 2 groups: two-vessel with LAD involvement and two-vessel without LAD involvement (P = .558).

CONCLUSION

In patients with single- or two-vessel territory perfusion abnormalities with similar size and severity of perfusion defects, the location of defect did not impact future cardiac events. Location of myocardial perfusion defect on SPECT imaging may not be helpful in clinical decision making.

CMRI based 3D left ventricle motion analysis on patients with acute myocardial infarction

3D Quantitative measurement of left ventricle (LV) motion on patients with acute myocardial infarction has been recognized as essential for effective LV function diagnosis. This paper presents a method to quantify 3D LV motion obtained from conventional CINE MRI using image analysis based on mathematical modeling. Level set method is employed for segmentation, and a 3D LV geometry was reconstructed by co-registering different views of MRI images. A mathematical model of LV geometry was then constructed to quantitatively describe the LV wall inward motion. The results using real data show that the method is able to quantify the LV inward motion, and can clearly represent the changed motion pattern with the follow-up data. Furthermore, the LV motion analysis for 8 patients with acute myocardial infarction (MI) show that high inward motion occurs mainly in the basal region of LV while a negative relation is found between LV ejection fraction (EF) improvement after acute MI and solely basal region inward motion, which could be helpful for diagnosis and LV EF recovery prediction.

Quantitative three-dimensional wall motion analysis predicts ischemic region size and location

Stress echocardiography is an important screening test for coronary artery disease. Currently, cardiologists rely on visual analysis of left ventricular (LV) wall motion abnormalities, which is subjective and qualitative. We previously used finite-element models of the regionally ischemic left ventricle to develop a wall motion measure, 3DFS, for predicting ischemic region size and location from real-time 3D echocardiography (RT3DE). The purpose of this study was to validate these methods against regional blood flow measurements during regional ischemia and to compare the accuracy of our methods to the current state of the art, visual scoring by trained cardiologists. We acquired RT3DE images during 20 brief (<2 min) coronary occlusions in dogs and determined ischemic region size and location by microsphere-based measurement of regional perfusion. We identified regions of abnormal wall motion using 3DFS and by blinded visual scoring. 3DFS predicted ischemic region size well (correlation r (2) = 0.64 against microspheres, p < 0.0001), reducing error by more than half compared to visual scoring (8 +/- 9% vs. 19 +/- 14%, p < 0.05), while localizing the ischemic region with equal accuracy. We conclude that 3DFS is an objective, quantitative measure of wall motion that localizes acutely ischemic regions as accurately as wall motion scoring while providing superior quantification of ischemic region size.

Improvement in survival following successful percutaneous coronary intervention of coronary chronic total occlusions: variability by target vessel

OBJECTIVES

This study compared the survival benefit of opening a chronic total occlusion (CTO) of the left anterior descending (LAD), left circumflex (LCX), or right coronary artery (RCA).

BACKGROUND

Previous analyses demonstrate improved survival following successful percutaneous coronary intervention (PCI) for CTO.

METHODS

Eligible patients underwent attempted CTO PCI in a single vessel. Procedural success rates were calculated for each vessel. The primary end point was survival at 5 years, compared across target vessel groups stratified by procedural success.

RESULTS

There were 2,608 patients included. The LAD was the target vessel in 936 (36%), the LCX in 682 (26%), and the RCA in 990 (38%) patients. Angiographic success rates for LAD were 77%, LCX 76%, and RCA 72%. Baseline demographics and comorbidities were well matched, though there were significantly more males in the LCX compared with LAD or RCA groups (80% vs. 75% and 73%, respectively, p = 0.005). Procedural success compared with failure was associated with improved 5-year survival in the LAD (88.9% vs. 80.2%, p < 0.001) group, but not in the LCX (86.1% vs. 82.1%, p = 0.21) and RCA groups (87.7% vs. 84.9%, p = 0.23). In multivariable analysis, CTO PCI success in the LAD group remained associated with decreased mortality risk (HR: 0.61, 95% CI: 0.42 to 0.89).

CONCLUSIONS

The data suggest that PCI for CTO of the LAD, but not LCX or RCA, is associated with improved long-term survival. This information may assist in selecting patients for attempted CTO PCI.

Dobutamine cardiac magnetic resonance results predict cardiac prognosis in women with known or suspected ischemic heart disease

OBJECTIVES

The purpose of this study was to determine the prognostic utility of dobutamine cardiac magnetic resonance (DCMR) stress test results in women.

BACKGROUND

To date, the preponderance of studies reporting the utility of DCMR stress results for predicting cardiac prognosis have been performed in men. We sought to determine the utility of DCMR results for predicting cardiac prognosis in women.

METHODS

Two hundred sixty-six consecutively referred women underwent DCMR in which left ventricular wall motion (LVWM) was assessed at rest and after intravenous dobutamine and atropine. Inducible LVWM abnormalities were identified during testing. Women were contacted to determine the post-DCMR occurrence of a cardiac event. All events were substantiated according to defined criteria and then were verified after a thorough medical record review by individuals blinded to testing data.

RESULTS

Women were contacted an average of 6.2 +/- 1.6 (median 6.2, range 0.8 to 10.4) years after DCMR; 27% of the women experienced an inducible LVWM abnormality during testing. In those with and without inducible LVWM abnormalities, the proportion of women with cardiac events were 63% versus 30%, respectively, (hazard ratio [HR]: 2.7; 95% confidence interval [CI]: 1.8 to 4.3 for the presence of inducible LVWM abnormalities p < 0.0001). The proportion of women with myocardial infarction (MI) and cardiac death were 33.3% and 7.5%, respectively. This resulted in a HR for MI and cardiac death of 4.1 (95% CI: 2.2 to 9.4) for those with versus those without inducible LVWM abnormalities; p < 0.0001. A subgroup analysis was performed in women without a history of coronary artery disease and in those with LVWM abnormalities, DCMR remained an adverse predictor of cardiac events (HR: 4.0, 95% CI: 1.8 to 9.0, p = 0.003).

CONCLUSIONS

Inducible LVWM abnormalities during DCMR predict cardiac death and MI in women. Similar to men, these results indicate that DCMR is a valuable noninvasive stress imaging modality for identifying cardiac risk in women with known or suspected ischemic heart disease.

Stress echocardiography expert consensus statement: European Association of Echocardiography (EAE) (a registered branch of the ESC)

Stress echocardiography is the combination of 2D echocardiography with a physical, pharmacological or electrical stress. The diagnostic end point for the detection of myocardial ischemia is the induction of a transient worsening in regional function during stress. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging, but at a substantially lower cost, without environmental impact, and with no biohazards for the patient and the physician. Among different stresses of comparable diagnostic and prognostic accuracy, semisupine exercise is the most used, dobutamine the best test for viability, and dipyridamole the safest and simplest pharmacological stress and the most suitable for combined wall motion coronary flow reserve assessment. The additional clinical benefit of myocardial perfusion contrast echocardiography and myocardial velocity imaging has been inconsistent to date, whereas the potential of adding - coronary flow reserve evaluation of left anterior descending coronary artery by transthoracic Doppler echocardiography adds another potentially important dimension to stress echocardiography. New emerging fields of application taking advantage from the versatility of the technique are Doppler stress echo in valvular heart disease and in dilated cardiomyopathy. In spite of its dependence upon operator's training, stress echocardiography is today the best (most cost-effective and risk-effective) possible imaging choice to achieve the still elusive target of sustainable cardiac imaging in the field of noninvasive diagnosis of coronary artery disease.

Risk Stratification by Treadmill Exercise Echocardiography in Patients with Excellent Exercise Capacity

BACKGROUND

The incremental value of exercise echocardiography (EE) has been demonstrated to be maximal in patients with moderate pretest probability for coronary artery disease, but there is a lack of data in patients with low pretest probability or patients with good functional capacity.

METHODS

To investigate whether such incremental value is maintained in patients with excellent exercise capacity, we studied 1,433 patients who had excellent exercise capacity (>or=8 METs for women, >or=10 METs for men).

RESULTS

During a follow-up of 2.3 +/- 1.5 years, 42 hard events occurred (cardiac death or nonfatal myocardial infarction). Variables independently associated to hard events were male gender (P = 0.04), % of the age-predicted maximum heart rate (P = 0.02), chronotropic reserve (P = 0.002), and abnormal EE (P = 0.03; incremental P value of EE = 0.03).

CONCLUSIONS

EE has incremental value over clinical variables, resting echocardiography, and exercise testing variables in patients with excellent exercise capacity. EE may be preferable to ECG exercise testing even in patients expected to have good exercise capacity.

The Prognostic Value of Normal Exercise Myocardial Perfusion Imaging and Exercise Echocardiography

OBJECTIVES

The purpose of this work was to determine the prognostic value of normal exercise myocardial perfusion imaging (MPI) tests and exercise echocardiography tests, and to determine the prognostic value of these imaging modalities in women and men.

BACKGROUND

Exercise MPI and exercise echocardiography provide prognostic information that is useful in the risk stratification of patients with suspected coronary artery disease (CAD).

METHODS

We searched the PubMed, Cochrane, and DARE databases between January 1990 and May 2005, and reviewed bibliographies of articles obtained. We included prospective cohort studies of subjects who underwent exercise MPI or exercise echocardiography for known or suspected CAD, and provided data on primary outcomes of myocardial infarction (MI) and cardiac death with at least 3 months of follow-up. Secondary outcomes (unstable angina, revascularization procedures) were abstracted if provided. Studies performed exclusively in patients with CAD were excluded.

RESULTS

The negative predictive value (NPV) for MI and cardiac death was 98.8% (95% confidence interval [CI] 98.5 to 99.0) over 36 months of follow-up for MPI, and 98.4% (95% CI 97.9 to 98.9) over 33 months for echocardiography. The corresponding annualized event rates were 0.45% per year for MPI and 0.54% per year for echocardiography. In subgroup analyses, annualized event rates were <1% for each MPI isotope, and were similar for women and men. For secondary events, MPI and echocardiography had annualized event rates of 1.25% and 0.95%, respectively.

CONCLUSIONS

Both exercise MPI and exercise echocardiography have high NPVs for primary and secondary cardiac events. The prognostic utility of both modalities is similar for both men and women.

Risk stratification by treadmill exercise echocardiography

BACKGROUND

Although exercise echocardiography (EE) has value for the diagnosis of coronary artery disease (CAD), it's not clear whether it may be useful for risk assessment in all categories of patients. To determine whether: 1) there is an incremental value of EE over clinical, exercise and resting echocardiographic variables for the prediction of events according to the pre-test probability of CAD; and 2) the number, location of the diseased territories, and nature of the disease affect the risk stratification, we studied 2436 patients referred for EE that were followed for 2.1 +/- 1.5 years.

METHODS

Based on a pre-test score, previous myocardial infarction (MI) or revascularizations, 1242 patients were considered as having high, 1038 moderate, and 156 low pre-test probability.

RESULTS

There were 89 hard events (myocardial infarction or cardiovascular death) in the 1203 patients with abnormal EE vs. 31 events in the 1233 with normal EE (p < 0.0001). Gender, Mets, heart rate x blood pressure, resting wall motion score index and number of involved territories at exercise were independently associated to hard events (final Chi-square = 170, incremental p value of exercise echo <0.0001). The incremental value of exercise echo over other variables was found in patients with the different pre-test probabilities.

CONCLUSIONS

Exercise echocardiography has incremental value over clinical, exercise and resting echocardiographic variables in patients with different pre-test probabilities of CAD.

Incremental prognostic value of stress echo positivity in the left anterior descending coronary artery territory

BACKGROUND

Dipyridamole stress echo (DSE) positivity is usually titrated according to presence and severity of the induced wall motion abnormalities. The purpose of our study is to assess whether the location of DSE positivity might add to prognostic stratification.

METHODS

The study enrolled 112 patients with known or suspected coronary artery disease (CAD) and without a history of prior myocardial infarction. They were consecutively submitted to DSE (0.84 mg/Kg in 10 min followed by atropine administration, when needed) and coronary angiography (within a 15+/-7 day period). End points at follow-up were cardiac death and acute coronary syndromes.

RESULTS

Twenty-seven patients had a negative, and 85 a positive DSE (47 in the LAD territory). Angiographically assessed CAD was present in 82 patients (LAD in 59). At a follow-up of 9+/-7 months, there were 28 events of cardiac deaths or acute coronary syndromes. Event-free survival was lower in patients with positive DSE (any location) compared to those with negative DSE (47% vs 89%, p=0.003). In the subset with positive DSE, event-free survival was lower in patients with wall motion abnormalities in the LAD territory compared to those with dysfunction in the left circumflex and right coronary artery territory (31% vs 72%, p=0.00012 ). At multivariate analysis, stress echo positivity in the LAD territory was independently associated with increased risk (HR: 9.51, CI: 1.61 to 56.11, p<0.013) and outperformed angiographically assessed LAD stenosis (HR: 0.36, CI: 0.06 to 2.24, p: NS).

CONCLUSIONS

In CAD patients, wall motion abnormalities in the LAD territory during DSE identified a higher risk subgroup. Functional stress echo positivity on the LAD territory overcame the prognostic impact of an anatomic, angiographically assessed LAD disease.

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

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

Emergency cardiac imaging: state of the art

Multiple strategies and testing modalities are available to evaluate patients presenting to the emergency department with cardiac complaints. Many provide anatomic and prognostic information about coronary stenosis and long-term out-comes. Although nuclear and stress echo imaging have the ability to predict outcomes in patients in the emergency department population, the newer modalities of cardiac imaging (EBCT, MDCT,and CMR) continue to show promising results and may soon be incorporated into emergency department chest pain centers. Protocols can be developed within an institution to meet the needs of the patient population while minimizing risk and improving outcomes for all patients.

Comparison of the long-term survival benefits associated with revascularization or medical therapy in patients with known coronary artery disease undergoing transesophageal atrial pacing stress echocardiography

Although the utility of stress echocardiography for the diagnosis and prognostic evaluation of patients with suspected coronary artery disease (CAD) has been widely reported, few studies have evaluated the role of revascularization in relation to the presence of inducible ischemia during stress in patients with known CAD. The study population consisted of 295 consecutive patients who underwent transesophageal atrial pacing stress echocardiography (TAPSE) in the echocardiographic laboratory of our division between January 1988 and September 1997, in whom coronary angiography was performed within 10 days of the test. Patients were then assigned to revascularization or medical treatment according to the treatment given within 60 days of TAPSE. Cardiac-related deaths were higher in medically treated (19 of 135) than in revascularized (8 of 160) patients (p = 0.03). Parameters measured with TAPSE, i.e., positivity of the test, change in wall motion score index (DeltaWMSI and peak WMSI) were significantly related to mortality in medically treated patients but not in revascularized patients. At multivariate analysis, DeltaWMSI remained the most powerful predictor of cardiac death in medically treated patients (p = 0.005). Mortality progressively increased with increments in extent of inducible ischemia among medically treated patients (5 of 71 patients in DeltaWMSI 0, 3 of 27 in DeltaWMSI 0 to 25, 11 of 37 patients in DeltaWMSI >25) but not among revascularized patients (3 of 58 patients in DeltaWMSI 0, 2 of 51 in DeltaWMSI 0 to 25, 3 of 51 patients in DeltaWMSI >25). The survival curve in medically treated patients with ischemia in a remote zone (24 patients, 8 deaths) was worse than in other groups of medically treated patients (41 patients, 6 deaths). In conclusion, in patients with known CAD, the presence and extent of ischemia as evaluated with TAPSE worsens survival, if revascularization is not performed. In patients without ischemia at TAPSE, revascularization or medical therapy are equally effective.

Stress Function Index, a Novel Index for Risk Stratification and Prognosis Using Stress Echocardiography

OBJECTIVES

The purpose of the study was to define an appropriate parameter for risk stratification and prognosis of patients undergoing stress echocardiography.

BACKGROUND

Among stress echocardiography variables, peak wall-motion score index (WMSI) and ejection fraction (EF) have been shown to be independent and significant predictors of cardiovascular morbidity and mortality. Data on the impact and importance of each parameter in risk stratification and prognosis are limited.

METHODS

We evaluated 1560 patients (59 +/- 13 years; 51% men) undergoing stress echocardiography (36% treadmill, 64% dobutamine). Peak WMSI was derived from the cumulative sum of 16 left ventricular segments divided by sum of visualized segments at peak stress. The ratio of peak WMSI to EF was calculated for the entire cohort. Based on this ratio and using the receiver operating characteristic curve, patients were divided into 3 groups: low- (< 1.9), intermediate- (1.9-3.1), and high- (> 3.1) risk subgroups. Follow-up (2.8 +/- 1.1 years) for confirmed myocardial infarction (n = 26) and cardiac death (n = 38) were obtained.

RESULTS

Stress echocardiography effectively risk stratified patients into low- (0.7%/y), intermediate- (2.0%/y), and high- (4.4%/y) risk subgroups (P < .0001) based on the ratio of peak WMSI to EF. Cox proportional hazard model showed that risk stratification based on the ratio of peak WMSI to EF (global chi2 = 106.05; P < .0001) provided incremental value beyond that provided by risk stratification by peak WMSI (global chi2 = 79.23; P < .0001) or risk stratification by EF alone (global chi2 = 87.12; P < .0001).

CONCLUSIONS

The ratio of peak WMSI to EF (stress function index) provides best incremental prognostic value and effectively risk stratifies patients into low-, intermediate-, and high-risk subgroups and is better than risk stratification by either peak WMSI or EF alone. The results of stress echocardiography should routinely combine peak WMSI and EF for effective risk stratification.