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

Direct correlation between ischemic burden induced by dipyridamole and stress peak filling rate: a gated perfusion single-photon emission computed tomography study

AIM AND PATIENTS

The aim of the present study was to assess the effects of dipyridamole on stress and rest peak filling rate in consecutive patients who showed perfusion and, or function abnormalities at Gated-SPECT. Were enrolled 96 patients (73 males (76%); mean age 71.7 ± 9.57). Forty patients (41.7%) had an history of myocardial infarction and fifty-seven (59.4%) of previous cardiac revascularization. All patients underwent a 2-day 99mTc-SestaMIBI gated perfusion SPECT protocol.

RESULTS

Twenty-nine (30.2%) patients showed fixed perfusion defects, 54 (56.2%) showed partially or completely reversible ones, while 13 (13.5%) showed normal perfusion but reduced LVEF. SSS was significantly higher than SRS (9.55 ± 9.29 vs. 7.10 ± 8.48; P = 0.0001). Stress peak filling rate was not significantly higher than rest peak filling rate (1.73 EDV/s ± 0.69 EDV/s vs. 1.67 EDV/s ± 0.56 EDV/s; P = 0.62). At a multivariate regression analysis, only stress peak filling rate, as independent variable, was directly correlated with myocardial ischemia (SDS) (P = 0.018). We divided patients according to SDS in those with mild (SDS < 5) and severe (SDS ≥ 5) ischemia. Stress peak filling rate was the only parameter significantly different between groups.

CONCLUSION

Stress PFR showed a better correlation with the degree of ischemia compared to the remaining perfusion and functional parameters. The direct correlation between SDS and stress PFR leads us to speculate that dipyridamole could improve diastolic function in ischemic patients.

Noninvasive cardiovascular imaging for myocardial necrosis, viability, stunning and hibernation: evidence from an umbrella review encompassing 12 systematic reviews, 286 studies, and 201,680 patients

INTRODUCTION

The concomitant presence of myocardial necrosis with myocardial ischemia, stunning or hibernation may complicates appraisal of left ventricular (LV) function and patient management. Several imaging modalities have been proposed for the accurate assessment of myocardial necrosis, viability, stunning and hibernation, with mixed results. We aimed to review the evidence base on myocardial necrosis, stunning and hibernation by conducting an umbrella review (i.e. overview of systematic reviews).

EVIDENCE ACQUISITION

We searched PubMed and The Cochrane Library for meta-analyses focusing on the diagnostic, prognostic, or management appraisal of myocardial necrosis, viability, stunning and hibernation. Diagnostic test accuracy, prognostic yield, and clinical outcomes were systematically abstracted from shortlisted reviews.

EVIDENCE SYNTHESIS

From an initial set of 6069 citations, 12 systematic reviews were finally included, encompassing 286 studies and 201,680 patients. Cardiac magnetic resonance imaging (CMR) had favorable results in 4 reviews that focused on the diagnosis of myocardial stunning or hibernation in patients followed for 6±4 months after coronary revascularization (sensitivity 96% and specificity 91%). Positron emission tomography (PET), single photon emission tomography (SPECT) and CMR in 6 meta-analyses had each a significant and independent prognostic role for the prediction of fatal and non-fatal cardiovascular events in patients with follow-up of 2.8±1.7 years. Finally, 2 reviews with 2.3±1.1 years of follow-up showed moderate quality evidence in favor of coronary revascularization in patients with objective signs of myocardial viability.

CONCLUSIONS

The appraisal of myocardial necrosis and residual viability remains a cornerstone of the modern management of patients with CAD. Current imaging modalities (echocardiography, PET, SPECT and CMR) are widely used. Further trials using contemporary methods are warranted to further clarify the impact of viability assessment on patient management, and the cumulative risk of morbidity and mortality.

Better characterization of dipyridamole-induced myocardial stunning by systolic wall thickening. A gated perfusion SPECT study

AIM AND PATIENTS

The aim of the present study was to assess the additional value of systolic wall thickening to myocardial perfusion in diagnosing myocardial stunning induced by dipyridamole infusion. We selected 52 ischemic patients (43 males; mean age 65.5 ± 7.64), with CAD documented by angiography. Ischemia was defined as a summed difference score ≥ 5. All patients underwent a 2-day gated perfusion SPECT protocol. The patients received a dose of 740 MBq of 99mTc-tetrofosmin after stress and at rest.

RESULTS

The post-stress LVEF was significantly lower than rest LVEF (48.3% ± 14.5% vs. 50.7% ± 15%; P = 0.0001). The wall thickening summed difference score was 3.97 ± 3.84 (P = 0.0001). At a multivariate regression analysis, only WT-SDS as independent variable was significantly correlated with myocardial ischemia (SDS) (P = 0.001). We divided patients according to SDS in those with mild (SDS < 8) and severe (SDS ≥ 8) ischemia. WT-SDS, but not ∆LVEF, was significantly different between groups.

CONCLUSIONS

WT-SDS showed a better correlation with the degree of ischemia than the depression in the global function of the left ventricle. It allowed to better identify the stunning phenomenon in patients submitted to pharmacological stress.

Additional value of systolic wall thickening in myocardial stunning evaluated by stress-rest gated perfusion SPECT

AIM AND PATIENTS

The aim of the present study is to evaluate the additional value of systolic wall thickening to myocardial perfusion in diagnosing myocardial stunning in patients with angiography proven coronary artery disease. We selected 91 ischemic patients (82 males; mean age 59.7 ± 10.3) with CAD documented by angiography. Ischemia was defined as a summed difference score ≥5. All patients underwent a 2-day gated perfusion SPECT protocol. The patients received a dose of 740 MBq of 99mTc-tetrofosmin after stress and at rest. Treadmill maximal exercise tests were performed on all patients.

RESULTS

The post-stress LVEF was significantly lower than rest LVEF (48.1% ± 10.3% vs 50.3% ± 10.7%; P = .0001). The wall thickening summed difference score was 4.44 ± 4.13 (P = .0001). At a multivariate regression analysis, only WT-SDS as independent variable was significantly correlated with myocardial ischemia (SDS). We also divided patients according to SDS in those with mild (SDS < 8) and severe (SDS ≥ 8) ischemia. WT-SDS, but not ∆LVEF, was significantly different between groups.

CONCLUSIONS

WT-SDS, more than the depression in the global function (∆LVEF) of the left ventricle, correlates with the degree of ischemia and better identifies, when present, the stunning phenomenon.

Automated Quantitative Stress Perfusion in a Clinical Routine

Cardiovascular magnetic resonance (CMR) perfusion imaging is a robust noninvasive technique to evaluate ischemia in patients with coronary artery disease (CAD). Although qualitative and semiquantitative methods have shown that CMR has high accuracy in diagnosing flow-obstructing lesions in CAD, quantitative ischemic burden is an important variable used in clinical practice for treatment decisions. Quantitative CMR perfusion techniques have evolved significantly, with accuracy comparable with both PET and microsphere evaluation. Routine clinical use of these quantitative techniques has been facilitated by the introduction of automated methods that accelerate the work flow and rapidly generate pixel-based myocardial blood flow maps.

International Study of Comparative Health Effectiveness with Medical and Invasive Approaches (ISCHEMIA) trial: Rationale and design

BACKGROUND

Prior trials comparing a strategy of optimal medical therapy with or without revascularization have not shown that revascularization reduces cardiovascular events in patients with stable ischemic heart disease (SIHD). However, those trials only included participants in whom coronary anatomy was known prior to randomization and did not include sufficient numbers of participants with significant ischemia. It remains unknown whether a routine invasive approach offers incremental value over a conservative approach with catheterization reserved for failure of medical therapy in patients with moderate or severe ischemia.

METHODS

The ISCHEMIA trial is a National Heart, Lung, and Blood Institute supported trial, designed to compare an initial invasive or conservative treatment strategy for managing SIHD patients with moderate or severe ischemia on stress testing. Five thousand one-hundred seventy-nine participants have been randomized. Key exclusion criteria included estimated glomerular filtration rate (eGFR) <30 mL/min, recent myocardial infarction (MI), left ventricular ejection fraction <35%, left main stenosis >50%, or unacceptable angina at baseline. Most enrolled participants with normal renal function first underwent blinded coronary computed tomography angiography (CCTA) to exclude those with left main coronary artery disease (CAD) and without obstructive CAD. All randomized participants receive secondary prevention that includes lifestyle advice and pharmacologic interventions referred to as optimal medical therapy (OMT). Participants randomized to the invasive strategy underwent routine cardiac catheterization followed by revascularization with percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) surgery, when feasible, as selected by the local Heart Team to achieve optimal revascularization. Participants randomized to the conservative strategy undergo cardiac catheterization only for failure of OMT. The primary endpoint is a composite of cardiovascular (CV) death, nonfatal myocardial infarction (MI), hospitalization for unstable angina, hospitalization for heart failure, or resuscitated cardiac arrest. Assuming the primary endpoint will occur in 16% of the conservative group within 4 years, estimated power exceeds 80% to detect an 18.5% reduction in the primary endpoint. Major secondary endpoints include the composite of CV death and nonfatal MI, net clinical benefit (primary and secondary endpoints combined with stroke), angina-related symptoms and disease-specific quality of life, as well as a cost-effectiveness assessment in North American participants. Ancillary studies of patients with advanced chronic kidney disease and those with documented ischemia and non-obstructive coronary artery disease are being conducted concurrently.

CONCLUSIONS

ISCHEMIA will provide new scientific evidence regarding whether an invasive management strategy improves clinical outcomes when added to optimal medical therapy in patients with SIHD and moderate or severe ischemia.

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.

Prognostic value of myocardium perfusion imaging with a new reconstruction algorithm

BACKGROUND

It has been demonstrated that a new reconstruction algorithm for myocardium perfusion imaging (MPI) allows faster acquisition with similar accuracy. The prognostic value of MPI performed with this software and short acquisition time is unknown.

METHODS

To determine the prognostic value we followed 3184 consecutive MPI patients between March 2008 and March 2010. A 2-day protocol with low dose 99mTc-MIBI (10-12 mCi) and a 6-minute acquisition was used. Exercise stress was used in 62.6% of the studies. Scans were reconstructed using the software "Evolution for cardiac". Perfusion defects were quantified by summed stress score (SSS) and categorized in four groups: SSS0 = 0; SSS1 = 1-3; SSS2 = 4-8; and SSS3 ≥ 9. Patients were phone contacted every 6 months for follow up and hard events were defined as death or myocardial infarction (MI) and total events as hard events plus late revascularization.

RESULTS

The mean radiation dose was <7 mSv/patient. Mean F/U was 33 ± 20 months; 140 of the patients were lost to follow up and 86 were censored due early revascularization (<60 days after MPS). There were 140 hard events: 89 deaths and 51 MI. Mean age was 61.5 ± 12.3 years and 57.7% were male. Hard event rate was 0.8%/year in patients with normal MPS and 3.7%/year in those with abnormal MPS. Patients with larger defects had nine times more hard events than patients with SSS = 0 (14.2% vs 1.6%). Revascularization was more frequent in patients with abnormal MPS than normal MPS (21.7% vs 3.9%; P < 0.001). Cox proportional hazard analysis showed that SSS was an independent predictor of hard events and revascularization.

CONCLUSIONS

The use of reduced-dose, fast myocardial perfusion SPECT and the new processing algorithm lowers acquisition time and radiation exposure compared to conventional SPECT without compromising the well-established prognostic value of MPI.

Cost-effectiveness analysis for imaging techniques with a focus on cardiovascular magnetic resonance

With the need for healthcare cost-containment, increased scrutiny will be placed on new medical therapeutic or diagnostic technologies. Several challenges exist for a new diagnostic test to demonstrate cost-effectiveness. New diagnostic tests differ from therapeutic procedures due to the fact that diagnostic tests do not generally directly affect long-term patient outcomes. Instead, the results of diagnostic tests can influence management decisions for patients and by this route, diagnostic tests indirectly affect long-term outcomes. The benefits from a specific diagnostic technology depend therefore not only on its performance characteristics, but also on other factors such as prevalence of disease, and effectiveness of existing treatments for the disease of interest. We review the concepts and theories of cost-effectiveness analyses (CEA) as they apply to diagnostic tests in general. The limitations of CEA across different study designs and geographic regions are discussed, and we also examine the strengths and weakness of the existing publications where CMR was the focus of CEA compared to other diagnostic options.

How and when to decide on revascularization in stable ischemic heart disease

OPINION STATEMENT

Coronary artery disease is the leading cause of death and disability worldwide. While an invasive strategy of early revascularization reduces cardiovascular morbidity and mortality in patients with acute coronary syndromes, there is no convincing evidence that this strategy leads to an incremental survival advantage for patients with stable ischemic heart disease (SIHD) beyond that achieved by optimal medical therapy. Two landmark trials, COURAGE and BARI 2D, suggest that a strategy of aggressive medical therapy is a reasonable initial approach to such patients. However, there remain certain groups of patients, those with at least moderate ischemia on baseline stress testing, where there is still clinical equipoise. Major society guidelines favor revascularization based on observational data and trials of CABG conducted decades ago, yet data from modern randomized trials are lacking. Ongoing trials such as ISCHEMIA should provide clinicians with evidence to guide selection of the appropriate initial management strategy for patients with SIHD.

Coronary computed tomographic angiography as a gatekeeper to invasive diagnostic and surgical procedures: results from the multicenter CONFIRM (Coronary CT Angiography Evaluation for Clinical Outcomes: an International Multicenter) registry

OBJECTIVES

This study sought to examine patterns of follow-up invasive coronary angiography (ICA) and revascularization (REV) after coronary computed tomography angiography (CCTA).

BACKGROUND

CCTA is a noninvasive test that permits direct visualization of the extent and severity of coronary artery disease (CAD). Post-CCTA patterns of follow-up ICA and REV are incompletely defined.

METHODS

We examined 15,207 intermediate likelihood patients from 8 sites in 6 countries; these patients were without known CAD, underwent CCTA, and were followed up for 2.3 ± 1.2 years for all-cause mortality. Coronary artery stenosis was judged as obstructive when ≥50% stenosis was present. A multivariable logistic regression was used to estimate ICA use. A Cox proportional hazards model was used to estimate all-cause mortality.

RESULTS

During follow-up, ICA rates for patients with no CAD to mild CAD according to CCTA were low (2.5% and 8.3%), with similarly low rates of REV (0.3% and 2.5%). Most ICA procedures (79%) occurred ≤3 months of CCTA. Obstructive CAD was associated with higher rates of ICA and REV for 1-vessel (44.3% and 28.0%), 2-vessel (53.3% and 43.6%), and 3-vessel (69.4% and 66.8%) CAD, respectively. For patients with <50% stenosis, early ICA rates were elevated; over the entirety of follow-up, predictors of ICA were mild left main, mild proximal CAD, respectively, or higher coronary calcium scores. In patients with <50% stenosis, the relative hazard for death was 2.2 (p = 0.011) for ICA versus no ICA. Conversely, for patients with CAD, the relative hazard for death was 0.61 for ICA versus no ICA (p = 0.047).

CONCLUSIONS

These findings support the concept that CCTA may be used effectively as a gatekeeper to ICA.

Baseline stress myocardial perfusion imaging results and outcomes in patients with stable ischemic heart disease randomized to optimal medical therapy with or without percutaneous coronary intervention

BACKGROUND

The COURAGE trial reported similar clinical outcomes for patients with stable ischemic heart disease (SIHD) receiving optimal medical therapy (OMT) with or without percutaneous coronary intervention (PCI). The current post hoc substudy analysis examined the relationship between baseline stress myocardial ischemia and clinical outcomes based on randomized treatment assignment.

METHODS

A total of 1,381 randomized patients (OMT n = 699, PCI + OMT n = 682) underwent baseline stress myocardial perfusion single-photon emission computed tomographic imaging. Site investigators interpreted the extent of ischemia by the number of ischemic segments using a 6-segment myocardial model. Patients were divided into those with no to mild (<3 ischemic segments) and moderate to severe ischemia (≥ 3 ischemic segments). Cox proportional hazards models were calculated to assess time to the primary end point of death or myocardial infarction.

RESULTS

At baseline, moderate to severe ischemia occurred in more than one-quarter of patients (n = 468), and the incidence was comparable in both treatment groups (P = .36). The primary end point, death or myocardial infarction, was similar in the OMT and PCI + OMT treatment groups for no to mild (18% and 19%, P = .92) and moderate to severe ischemia (19% and 22%, P = .53, interaction P value = .65). There was no gradient increase in events for the overall cohort with the extent of ischemia.

CONCLUSIONS

From the COURAGE trial post hoc substudy, the extent of site-defined ischemia did not predict adverse events and did not alter treatment effectiveness. Currently, evidence supports equipoise as to whether the extent and severity of ischemia impact on therapeutic effectiveness.

Quantification of myocardial perfusion reserve at 1.5 and 3.0 Tesla: a comparison to fractional flow reserve

The objective of this study was to compare quantitative analysis of cardiac magnetic resonance (CMR) perfusion at 1.5 and 3 T against fractional flow reserve (FFR) as measured invasively. FFR is considered by many investigators to be a reliable standard to determine hemodynamically significant coronary artery stenoses. Quantitative 1.5 and 3 T CMR is capable to noninvasively determine myocardial perfusion reserve, but have not been compared against each other and validated against FFR as standard reference. Patients with suspected or known coronary artery disease (CAD) underwent CMR at at both field strengths, 1.5 and 3 T, and FFR. 34 patients were included into the study. Quantitative myocardial perfusion reserve was calculated in 544 myocardial segments at 1.5 and 3 T, respectively. FFR was measured in 109 coronary arteries. FFR ≤ 0.8 was regarded relevant. Reduced FFR (≤0.8) was found in 38 coronary arteries (19 LAD, 8 LCX and 11 RCA). Receiver operator curve analysis yielded higher area under the curve for 3 T CMR in comparison to 1.5 T CMR (0.963 vs. 0.645, p < 0.001) resulting in higher sensitivity (90.5 vs. 61.9 %) and specificity (100 vs. 76.9 %). Quantitative analysis of CMR myocardial perfusion reserve at 1.5 and 3 T is capable to detect hemodynamic significance of coronary artery stenoses. Diagnostic accuracy at 3 T is to be superior to 1.5 T.

Is cardiac catheterization necessary before initial management of patients with stable ischemic heart disease? Results from a Web-based survey of cardiologists

BACKGROUND

It is unknown whether preconceived beliefs regarding the need for cardiac catheterization and revascularization in patients with stable ischemic heart disease (SIHD) would preclude a study randomizing patients with significant ischemia to a conservative strategy. Given the widespread practice of performing revascularization in patients with SIHD, we assessed the feasibility of conducting a randomized trial comparing initial invasive and conservative strategies in patients with SIHD and moderate or severe ischemia.

METHODS

An online survey to cardiologists queried their willingness to enroll a sample patient with frequent stable angina, >10% myocardial ischemia, and normal ejection fraction into a randomized trial with a 50% chance of being conservatively managed without cardiac catheterization.

RESULTS

Among 499 respondents, 57% (95% CI 53%-62%) were willing to enroll the patient. Among 207 cardiologists unwilling to enroll, 55% (95% CI 48%-61%) would be willing if they knew the patient did not have very high-risk features on stress imaging, yielding a total of 80% (95% CI 76%-83%) of cardiologists willing to enroll. No differences were observed among different types of cardiologists (interventional, invasive/noninterventional, and noninvasive). Seventy-one percent (95% CI 67%-75%) were more likely to try initial medical therapy after the publication of the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation trial results.

CONCLUSIONS

Most surveyed cardiologists were willing to enroll SIHD patients with at least moderate ischemia into a trial with an initial noninvasive strategy arm. These findings support the feasibility of planning a large-scale trial to test the role of cardiac catheterization and revascularization in the initial management of SIHD patients with moderate or severe ischemia.

Estimation of cardiac event risk by gated myocardial perfusion imaging and quantitative scoring methods based on a multi-center J-ACCESS database

BACKGROUND

Myocardial perfusion imaging (MPI) has been used to estimate cardiac event risk. The aim of the present study is to achieve stable risk estimation based on perfusion scoring and a multi-center prognostic database.

METHODS AND RESULTS

Multivariate logistic regression analysis was performed to estimate cardiac event risk based on a J-ACCESS study. A stress-MPI was performed in 45 patients with coronary artery disease (CAD) and in 25 non-CAD patients. Perfusion defect scoring of summed stress score (SSS) was performed by 5 methods: (1) visual scoring; (2) automatic scoring of 3 short-axis and 1 vertical long-axis slices; (3) visual modification of Method 2; (4) automatic polar map scoring based on a Japanese multi-center database; and (5) visual modification of Method 4. Agreement of SSS between 2 observers was good (r=0.87-0.97). Agreement of estimated cardiac event risk between observers and among 5 methods was very good (r=0.99-1.00). Regarding diagnostic accuracy for CAD, Method 5 showed optimal diagnostic yields (sensitivity 84%, accuracy 77%).

CONCLUSIONS

Estimation of cardiac event risk in conjunction with polar map segmentation and common normal databases resulted in stable risk values, and might be used for risk stratification in patients suspected of having CAD.

Stress echocardiography in the district hospital setting: a cost-saving analysis

AIMS

Accurate and cost-effective techniques are required for investigating patients experiencing chest pain, given the significant workload this patient cohort represents. We determined the cost impact of stress echocardiography compared with myocardial perfusion scintigraphy and coronary angiography in the investigation of patients with chest pain deemed unsuitable for exercise treadmill testing.

METHODS AND RESULTS

A total of 200 patients with chest pain-with a low-intermediate probability of coronary artery disease-consecutively referred for stress echocardiography were recruited. Referring clinicians were asked which management strategy they would have chosen were the stress echocardiography service unavailable. The cost saving of stress echocardiography, an accuracy analysis, and adverse outcomes at 6 and 24 months follow-up were determined. The total cost attributable to the stress echocardiography service was Pound Sterling 58 368. If unavailable, 78 (39%) patients would have been referred for angiography and 122 (61%) for perfusion scintigraphy at a cost of Pound Sterling 56 316 and Pound Sterling 42 090, respectively, with a total cost of Pound Sterling 98 406. This represents a cost saving of Pound Sterling 40 038.

CONCLUSION

Stress echocardiography is a cost saving method for the investigation of chest pain in patients with low-intermediate risk of flow limiting coronary artery disease in the district hospital setting.

Risk stratification by adenosine stress cardiac magnetic resonance in patients with coronary artery stenoses of intermediate angiographic severity

OBJECTIVES

The purpose of this study was to determine the role of adenosine stress cardiac magnetic resonance (CMR) for risk stratification in patients with coronary artery stenoses of intermediate angiographic severity.

BACKGROUND

Coronary angiography only provides a morphological description of coronary lesions. As the patient's prognosis is closely related to the functional significance of angiographically detected coronary lesions, a functional assessment is desirable in patients with coronary artery stenoses of intermediate severity.

METHODS

Myocardial perfusion measurements at rest and adenosine stress were performed on 81 patients (75.6% male, mean age 64.2 years) with stable angina pectoris (AP) and coronary artery stenoses of intermediate angiographic severity (50% to 75%). Regardless of the CMR result, all patients were treated conservatively with an intensified medical treatment, and a follow-up was performed after 18 +/- 8 months and 30 +/- 8 months. The primary end point was defined as a major adverse cardiac event (MACE): all-cause death, stroke, acute coronary syndrome; the secondary end point was defined as target vessel revascularization. Furthermore, AP and dyspnea were evaluated.

RESULTS

After the follow-up period of 30 +/- 8 months, 9 patients with perfusion deficit (PD) suffered from MACE, whereas no MACE occurred among the 36 patients without PD (p = 0.014). Among patients who had MACE, the number of ischemic segments (2.3 +/- 1.6 vs. 1.4 +/- 1.6, p = 0.0025) was significantly higher, whereas the number of delayed enhancement segments did not differ (1.4 +/- 1.6 vs. 1.6 +/- 2.3, p = 0.4). Target vessel revascularization was required in 38% of patients with PD and 6% of patients without PD (p = 0.005). In addition, the percentage of freedom from AP and dyspnea at the follow-up after 18 +/- 8 months was significantly lower among patients without perfusion deficit (69.4% vs. 15.6%; p = 0.0001). After a follow-up period of 30 +/- 8 months, the rate of AP (11.1% vs. 8.3%, p = 0.33) as well as the percentage of patients free of symptoms was similar in both groups (77.8% vs. 88.9%, p = 0.82).

CONCLUSIONS

Adenosine stress CMR may help to identify patients at risk who benefit from intensified medical treatment and close follow-up.

Left-ventricular power-to-mass ratio at peak exercise predicts mortality, heart failure, and cardiovascular events in patients with stable coronary artery disease: data from the Heart and Soul Study

BACKGROUND

Quantitative stress echocardiography enables calculation of left-ventricular power-to-mass ratio (LVPMR) at peak exercise, a novel measure of cardiac performance per unit mass of myocardial tissue. We hypothesized that LVPMR at peak exercise provides prognostic information beyond established echocardiographic indices such as left-ventricular ejection fraction (LVEF) and left-ventricular mass index (LVMI).

METHODS

LVPMR (watts/kilogram) at peak exercise was defined as (k x heart rate x mean arterial pressure x stroke volume)/LV mass. We measured LVPMR in 918 adults with stable ambulatory coronary artery disease recruited for the Heart and Soul Study. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for all-cause mortality, cardiovascular death, nonfatal myocardial infarction, heart failure hospitalization, and combined adverse cardiovascular events. Multivariate adjustments were made for established risk factors including LVEF and LVMI. The prognostic value of LVPMR was also compared with established exercise parameters using receiver-operating characteristic curve analysis.

RESULTS

Compared with patients in the highest LVPMR quartile, those in the lowest quartile were at increased risk of all-cause mortality (adjusted HR 1.9; 95% CI 1.1-3.3), heart failure hospitalization (adjusted HR 2.9; 95% CI 1.2-6.9), and combined adverse cardiovascular events (adjusted HR 1.9; 95% CI 1.1-3.4). In comparison with the rate-pressure product and the Duke treadmill score, LVPMR did not add significant prognostic value (p > 0.1 for c-statistic comparisons).

CONCLUSIONS

In patients with stable ambulatory coronary artery disease, LVPMR at peak exercise predicts mortality, heart failure hospitalization, and adverse cardiovascular events. However, LVPMR does not add significant prognostic information beyond established exercise test parameters.

Hemodynamic variables during stress testing can predict referral to early catheterization but failed to show a prognostic impact on emerging cardiac events in patients aged 70 years and older undergoing exercise (99m)Tc-sestamibi myocardial perfusion scintigraphy

The aim of the present study was to evaluate the prognostic value of hemodynamic variables during ergometric stress testing for (99m)Tc-sestamibi myocardial perfusion scintigraphy (MPS) as compared to several patient-related variables and MPS results with regard to referral to early coronary angiography (<3 months after MPS; CA) as well as cardiac event (CE) free survival in a study population aged > or =70 years. About 90 patients aged > or =70 years (74.5 +/- 3.6 years) who underwent ergometric stress/rest MPS were included in this study. About 19 hemodynamic variables during stress testing were assessed. Semiquantitative visual interpretation of MPS images were performed and Summed-Stress-(SSS), Summed-Difference-, and Summed-Rest-Scores were calculated. Emerging CE comprised myocardial revascularization and -infarction as well as cardiac-related death. Multivariate logistic regression analyses were performed for evaluation of independent prognostic impact of hemodynamic-, MPS- and clinical-variables with regard to referral to early catheterization as well as emerging CE. Kaplan-Meier survival- and log rank analyses were calculated for assessment of CE free survival. History of CAD (Odds ratio; OR: 99.3), low rest heart rate (OR: 14.9) and low peak systolic blood pressure (OR: 15.4) during ergometric stress testing as well as pathological SSS (OR: 48.4) were significantly associated with referral to CA. History of ischemic ECG (OR: 4.7) and pathological SSS (OR: 3.7) independently predicted emerging CE and were associated with a lower CE free survival. In patients aged > or =70 years, CA is independently predicted by clinical variables, pathological results of MPS and hemodynamic variables. In contrast, hemodynamic response to stress testing failed to show any predictive impact on emerging CE.

Yield of nuclear scan strategy in chest pain unit evaluation of special populations

BACKGROUND

Patients with chest pain (CP) and nondiagnostic ECG represent heterogeneous population in whom the evaluation of coronary risk factors including metabolic syndrome (MetS) and diabetes mellitus (DM) might improve risk stratification.

METHODS

We enrolled 798 consecutive CP patients; 14% presented with MetS and 10% with DM; the remaining 76% presented with other coronary risk profiles (others). All patients underwent maximal exercise tolerance test (ETT) and myocardial perfusion imaging (exercise-MPI). Those with positive testing underwent angiography, whereas the remaining patients were discharged and later followed up. Primary end-point was a composite of coronary stenoses greater than or equal to 50% documented by angiography or coronary events at follow-up.

RESULTS

Patients with MetS or DM had significantly lower survival free from end-point than those patients without (P<0.001). Exercise-MPI showed high negative predictive value in MetS, DM, and others (>96%); however, positive predictive value was 69, 74, and 52%, respectively (P<0.05). ETT alone showed negative predictive value (88%) which was significantly lower than exercise-MPI (98%), (MetS vs. others: P<0.001, and DM vs. others: P=0.05). The area under the receiver-operating characteristic curves obtained from the multivariate model includes clinical data alone, clinical data and ETT results, or clinical data and exercise-MPI results increase progressively.

CONCLUSION

A nuclear scan strategy in special populations, including CP patients with MetS or DM, is a valuable tool for risk stratification and adds incremental prognostic value over clinical and ETT values.

Clinical characteristics associated with poor long-term survival among patients with diabetes mellitus undergoing saphenous vein graft interventions

BACKGROUND

Limited data exist on the long-term outcomes among diabetic patients undergoing saphenous vein graft (SVG) interventions. Thus, the baseline clinical factors associated with long-term adverse events in these patients are less known.

METHODS

Accordingly, we analyzed 1,160 consecutive patients (37.7% with diabetes) undergoing SVG interventions from the Duke Cardiovascular Disease Database (1990-2003). Cox proportional hazards modeling was used to identify predictors of long-term death in diabetic patients. The most significant model predictors were then used to construct a decision tree providing unadjusted Kaplan-Meier survival estimates at a median follow-up of 4 years.

RESULTS

At median follow-up of 4 years, death (33.3% vs 18.1%, P < .0001; unadjusted hazard ratio 1.98, 95% CI 1.64-2.38) and death or myocardial infarction (49.6% vs 32.9%, unadjusted hazard ratio 1.71, 95% CI 1.462.00) were significantly higher in patients with diabetes mellitus compared with those without it. In patients with diabetes undergoing SVG interventions, a simple clinical decision algorithm, based on the most significant model predictors, demonstrated that 88% of patients without heart rate >80 beat/min, congestive heart failure, renal insufficiency, or hypertension survived after SVG intervention at median follow-up of 4 years. In contrast, none of the few patients with all these 4 factors survived at follow-up (100% mortality).

CONCLUSIONS

Compared with patients without diabetes, diabetic patients undergoing SVG intervention have significantly worse long-term outcomes with one third dying at median follow-up of 4 years. We provide a simple decision tool that allows stepwise risk-stratification using baseline factors in diabetic patients undergoing SVG interventions and identify 4 risk factors associated with extremely poor long-term survival in this cohort.

Impact of inducible ischemia by stress SPECT in cardiac risk assessment in diabetic patients: rationale and design of a prospective, multicenter trial

BACKGROUND

A prospective, multicenter trial has been designed to evaluate the impact of inducible ischemia by stress single photon emission computed tomography (SPECT) in diabetic patients and to define the role of SPECT in assessing the cardiac risk in such patients. This report presents the details and implications of the Impact of Inducible Ischemia by Stress SPECT (IDIS) trial design.

METHODS AND RESULTS

Between January 2002 and September 2005, 1006 consecutive patients (649 men and 357 women; mean age, 63 +/- 9 years) with at least a 5-year history of type 2 diabetes mellitus were enrolled. All patients underwent stress-rest sestamibi SPECT imaging with physical exercise (n = 573) or dipyridamole (n = 433). SPECT studies will be analyzed by use of a 17-segment scoring system to calculate left ventricular ejection fraction, summed stress score, summed rest score, and summed difference score. The SPECT study will be considered abnormal if the summed stress score is 3 or greater. Patients with abnormal studies will be considered to have ischemia if the summed difference score is 2 or greater.

CONCLUSION

The results of this trial should help to define the role of SPECT in assessing cardiac risk in diabetic patients. Furthermore, this trial will prospectively evaluate subsequent patient outcome during long-term follow-up.

Left ventricular opacification for the diagnosis of coronary artery disease with stress echocardiography: an angiographic study of incremental benefit and cost-effectiveness

BACKGROUND

Left ventricular opacification (LVO) improves image quality at stress echocardiography (SE). We examined whether routine use of LVO adds incremental benefit and is cost-effective for diagnosis of coronary artery disease (CAD).

METHODS

Contrast pharmacologic and/or exercise SE was performed in 135 patients (81 men; 56 +/- 10 years) undergoing coronary angiography. Observers sequentially interpreted first standard, then LVO images; a positive SE was defined by resting or inducible wall motion abnormality in > or = 2 segments. Coronary artery disease (75 patients, 119 territories) was defined as > 50% stenosis. Three cost-effectiveness models were studied, and a sensitivity analysis was performed.

RESULTS

Left ventricular opacification increased the sensitivity of SE (80%-91%; P = .03), including single-vessel CAD (65%-87%; P = .04), with no significant change in specificity (72%-77%; P = NS). Left ventricular opacification was of benefit to 14% of patients, unrelated to resting image quality. Use of LVO in all patients added 59% to the cost of the procedure (P < .001), at a cost of $1069 per additional correct diagnosis. In a cost-effectiveness model based on cardiac outcomes after SE, LVO resulted in an increase in total cost of $1069. A 3.7% improvement in sensitivity resulted in a negative cost to identify CAD, but even 15% to 20% improvements in specificity failed to balance the cost of contrast for exclusion of CAD.

CONCLUSIONS

Left ventricular opacification adds significant incremental diagnostic benefit to standard SE, especially single-vessel CAD. Despite improved sensitivity, the use of contrast in all patients was not cost-effective when analyzed with a model based on previously published patient outcomes.

Mortality risk associated with ejection fraction differs across resting nuclear perfusion findings

BACKGROUND

Left ventricular ejection fraction (LVEF) is a significant predictor of morbidity and death. The nuclear summed rest score (SRS) measures myocardial perfusion defects and provides prognostic information, but its effects on long-term outcomes are not fully established. Moreover, information regarding the potential interaction between these 2 covariates is limited. The purpose of this study was to determine whether the mortality risk associated with LVEF is the same across all values of SRS in a population undergoing evaluation for ischemic heart disease.

METHODS AND RESULTS

We examined 3,187 patients who underwent cardiac catheterization and perfusion single photon emission computed tomography imaging with a maximum follow-up of 8.1 years and median follow-up of 3.1 years. Cox proportional hazards modeling showed that increasing nuclear SRS and decreasing LVEF were independently associated with a higher long-term mortality rate, with a clinically significant interaction between them (P = .032). Patients with a normal LVEF and a high SRS (greater perfusion abnormality) have a prognosis similar to those with a reduced LVEF.

CONCLUSIONS

Resting perfusion studies provide prognostic information for long-term survival and significantly impact the interpretation of mortality risk associated with changes in LVEF. Patient prognostication, risk stratification, and future research using these variables should take this interaction into account.

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.

Clinical correlates of long-term mortality after percutaneous interventions of saphenous vein grafts

BACKGROUND

Increasing number of patients undergo percutaneous intervention of saphenous vein grafts (SVGs). However, the clinical factors associated with long-term mortality after SVG interventions are currently less known. Accordingly, the goal of present study was to evaluate clinical correlates of long-term mortality and to develop a simple bedside tool for risk stratification in patients undergoing SVG interventions.

METHODS

We analyzed 1019 patients undergoing SVG interventions from the Duke Cardiovascular Disease Database (1986-2003). Cox proportional hazards model was used to identify baseline variables associated with long-term mortality, and the model variables were then used to construct a nomogram for survival probability at 4 years.

RESULTS

At a median follow-up of 4 years, 24% of those undergoing SVG interventions died (interquartile range 2-7 years). Independent correlates of death at follow-up on multivariable analysis included presenting heart rate (hazard ratio [HR] 1.02, 95% CI 1.01-1.03), diabetes (HR 1.73, 95% CI 1.37-2.18), presenting heart failure (HR 1.62, 95% CI 1.27-2.06), age (per 10-year increase, HR 1.29, 95% CI 1.13-1.46), peripheral vascular disease (HR 1.59, 95% CI 1.23-2.04), renal insufficiency (HR 2.01, 95% CI 1.36-2.97), patent internal mammary graft (HR 0.67, 95% CI 0.53-0.86), body mass index < or = 25 kg/m2 (HR 0.91, 95% CI 0.85-0.97), carotid bruit (HR 1.44, 95% CI 1.12-1.85), S3 ventricular gallop (HR 1.83, 95% CI 1.11-3.03), and hypertension (HR 1.38, 95% CI 1.04-1.83) (c-index 0.83). Bootstrap validation confirmed excellent internal validity of the model (mean c-index 0.84, 95% CI 0.80-0.85).

CONCLUSION

Long-term survival after SVG intervention is poor, with one fourth of patients dying at median follow-up of 4 years. The nomogram developed using the model variables provides a method for clinicians to advise patients undergoing SVG interventions regarding their long-term prognosis, thereby enhancing discharge and long-term follow-up planning and setting up of realistic expectations.

Prognostic value of myocardial perfusion imaging in patients with known or suspected stable angina pectoris: Evaluation in a setting in which myocardial perfusion imaging did not influence the choice of treatment

OBJECTIVE

Previous investigations on the prognostic value of myocardial perfusion imaging (MPI) were performed under circumstances in which the test result was known to the patient's physician. We wanted to examine the prognostic value of MPI in patients with known or suspected stable angina in a setting in which MPI could not influence the diagnostic and therapeutic strategy.

DESIGN

A prospective series of 507 patients referred to coronary angiography for this condition were examined by MPI before angiography. Management was based on symptoms and angiographic findings, as the results of MPI were not communicated. Patients were followed for a mean of 45.3 +/- 7.7 months.

RESULTS

During follow-up, 20 patients (3.9%) suffered from myocardial infarction, 19 (3.8%) died and eight (1.6%) were revascularized >1 year after MPI resulting in a combined annual event rate of 2.5%. Patients with normal MPI had a low annual event rate of 1.6% (or 1.1% with regard to myocardial infarction or death only). In contrast, event rates in patients with reversible or mixed ischaemia were 4.0% per year. MPI added independent prognostic value to standard clinical data in a multivariate Cox model.

CONCLUSION

We could confirm that in patients with known or suspected stable angina, MPI is a valuable risk stratifying tool.

Cardiac magnetic resonance perfusion imaging for the functional assessment of coronary artery disease: a comparison with coronary angiography and fractional flow reserve

AIMS

Cardiac magnetic resonance perfusion imaging (CMRI) is a promising technique for non-invasive measurement of myocardial perfusion reserve. Fractional flow reserve (FFR) is an established invasive method for functional assessment of coronary artery disease (CAD). To prospectively assess the diagnostic value of CMRI for the detection of haemodynamically significant coronary lesions, compared with coronary angiography (CA) and FFR.

METHODS AND RESULTS

Forty-three patients with suspected or known CAD underwent CA, CMRI, and FFR measurement. First pass magnetic resonance perfusion examination was performed during hyperaemia (140 microg/kg/min adenosine over 6 min) and at rest. One hundred and twenty-nine perfusion territories were assessed by semi-quantitative evaluation of signal intensity-time curves using the myocardial perfusion reserve index (MPRI) [upslope(stress(corrected))/upslope(rest(corrected))]. Perfusion territories were categorized as normal (coronary stenosis < or = 50%), intermediate (stenosis > 50% and FFR > 0.75), or severe (stenosis > 50% and FFR < or = 0.75 or total occlusion). MPRI values (+/-SD) were significantly different between the three categories [normal, 2.2 +/- 0.5 vs. intermediate, 1.8 +/- 0.5 (P = 0.005) and intermediate vs. severe, 1.2 +/- 0.3 (P < 0.001)]. An MPRI cut-off value of 1.5 (derived from receiver operating characteristics analysis) distinguished haemodynamically relevant (severe) from non-relevant (normal and intermediate) stenoses with a sensitivity of 88% (CI 74-100%) and a specificity of 90% (CI 84-96%).

CONCLUSION

In contrast to earlier studies that compared CMRI with morphological examination (CA) alone, the present study compared CMRI with CA plus a standard invasive functional assessment (FFR) and demonstrated that CMRI is able to distinguish haemodynamically relevant from non-relevant coronary lesions with a high sensitivity and specificity and may therefore contribute to clinical decision-making.

MRI of Myocardial Perfusion

An overwhelming number of myocardial perfusion studies are done by nuclear isotope imaging. Magnetic resonance imaging during the first pass of an injected, contrast bolus has some significant advantages for detection of blood flow deficits, namely higher spatial resolution, absence of ionizing radiation, and speed of the test. Previous clinical studies have demonstrated that excellent sensitivity and specificity can be achieved with MR myocardial perfusion imaging for detecting coronary artery disease, and assessment of patients with acute chest pain. Furthermore, an absolute quantification of myocardial blood flow is feasible, as was demonstrated by comparison of MR perfusion imaging, to measurements with isotope labeled microspheres in experimental models. An integrated assessment of perfusion, function, and viability, is thus feasible by MRI to answer important clinical challenges such as the identification of stunned or hibernating, but viable myocardium.

Diagnostic accuracy of myocardial perfusion imaging in a study population without post-test referral bias

BACKGROUND

Most previous studies on the accuracy of myocardial perfusion imaging (MPI) are hampered by post-test referral bias, in that referral for coronary angiography was influenced by the MPI result. In this way, patients with a normal MPI result less frequently underwent catheterization, a tendency supposed to cause an underestimation of test specificity and an overestimation of test sensitivity.

METHODS AND RESULTS

MPI by use of a gated dual-isotope protocol was undertaken before angiography in 357 patients referred for angiography for suspected stable angina pectoris. The MPI reports were kept secret to prevent post-test referral bias. The MPI study was normal in 215 patients (60%) and showed reversible perfusion abnormalities in 118 (33%) and fixed defects in 24 (7%). Angiography was normal in 231 patients (65%) and revealed 1 or more significant stenoses in 126 (35%). With angiography as the reference, the sensitivity and specificity of MPI for detecting significant coronary artery stenosis were 75% and 79%, respectively.

CONCLUSIONS

In this prospective study without post-test referral bias, we found a lower sensitivity and slightly higher specificity than in studies with post-test referral bias. The imperfect accuracy may reflect differences between anatomic and physiologic imaging.

Sequential single-photon emission computed tomography myocardial perfusion imaging

The utility of stress myocardial perfusion imaging (MPI) for the diagnosis and prognosis of coronary artery disease (CAD) has been firmly established in numerous clinical studies and has become an essential component of clinical practice. Stress MPI is now used regularly to guide initial risk stratification and management of patients with CAD. Because stress MPI provides an assessment of the physiologic significance of CAD, it is a particularly attractive procedure for assessing follow-up risk. Today, sequential stress MPI is being used increasingly to track disease progression, assess follow-up risk, detect restenosis following revascularization, and evaluate the efficacy of aggressive medical therapy and risk-factor modification. By providing serial snapshots of the disease and its impact on perfusion, sequential stress MPI may alter treatment decisions and ultimately improve long-term patient management and outcomes. Use of sequential stress MPI to detect changes in perfusion following surgical or medical therapies is being tested currently in the Clinical Outcomes Using Revascularization and Aggressive Drug Evaluation (COURAGE) and Adenosine Sestamibi Single-Photon Emission Computed Tomography Postinfarction Evaluation (INSPIRE) trials.

Acute Myocardial Infarction Following a Negative Evaluation of Chest Pain

Although acute chest pain accounts for five million emergency room visits annually, only 10% represent acute myocardial infarctions (AMI). Even patients with negative evaluations of chest symptoms experience subsequent cardiac events. Patients readmitted with AMI within 90 days after a cardiac evaluation were examined to identify potential errors in management that may have Led to readmission. Only six of 2,340 patients met criteria for AMI after a negative work-up. No medical errors were found to account for the subsequent AMI. No other previously published reports have investigated the quality of chest pain evaluations to find missed opportunities for cardiac event prevention.

Systematic review of the prognostic effectiveness of SPECT myocardial perfusion scintigraphy in patients with suspected or known coronary artery disease and following myocardial infarction

OBJECTIVES

In patients with suspected or known coronary artery disease (CAD), or following myocardial infarction (MI), assessing the degree of ischaemia is important from a prognostic and therapeutic point of view. Single photon emission computed tomography (SPECT) myocardial perfusion scintigraphy (MPS) is a non-invasive technique that allows the presence, location and extent of ischaemia to be determined. The aim of this systematic review was to assess the prognostic effectiveness of SPECT MPS.

METHODS

We sought prognostic studies involving SPECT, exercise tolerance testing (ETT) and/or coronary angiography (CA) in people with suspected or known CAD, or following MI. Outcomes included cardiac death, non-fatal MI and revascularization. We searched the following databases: MEDLINE, PREMEDLINE, EMBASE, BIOSIS, Science Citation Index, the Cochrane Library, the Health Management Information Consortium and the Health Technology Assessment Database.

RESULTS

Twenty-one observational studies enrolling 53,762 people reported the general prognostic value of SPECT MPS. In multivariate analysis, SPECT MPS variables yielded both independent and incremental value to combinations of clinical, ETT and angiographic variables in predicting cardiac death or non-fatal MI. Three comparative studies reported lower revascularization rates following a SPECT MPS-CA strategy (6-21%) compared with direct CA (16-44%). Four observational studies enrolling 2106 people reported the prognostic value of SPECT for patients following MI. In multivariate analysis including clinical history, ETT, SPECT MPS and angiographic variables, strategies involving SPECT MPS provided independent and incremental prognostic performance in predicting future cardiac events.

CONCLUSIONS

SPECT MPS provides important additional information to that from ETT and/or CA that helps to risk-stratify patients with suspected or known CAD or following MI, enabling them to be managed more appropriately. Increasing the use of strategies involving SPECT MPS may identify lower risk patients for whom invasive CA might be avoided.

Impact of gender on risk stratification by exercise and dobutamine stress echocardiography: long-term mortality in 4234 women and 6898 men

AIMS

Prior research is limited with regard to the diagnostic and prognostic accuracy of commonplace cardiac imaging modalities in women. The aim of this study was to examine 5-year mortality in 4234 women and 6898 men undergoing exercise or dobutamine stress echocardiography at three hospitals.

METHODS AND RESULTS

Univariable and multivariable Cox proportional hazards models were used to estimate time to cardiac death in this multi-centre, observational registry. Of the 11 132 patients, women had a greater frequency of cardiac risk factors (P<0.0001). However, men more often had a history of coronary disease including a greater frequency of echocardiographic wall motion abnormalities (P<0.0001). During 5 years of follow-up, 103 women and 226 men died from ischaemic heart disease (P<0.0001). Echocardiographic estimates of left ventricular function (P<0.0001) and the extent of ischaemic wall motion abnormalities (P<0.0001) were highly predictive of cardiac death. Risk-adjusted 5-year survival was 99.4, 97.6, and 95% for exercising women with no, single, and multi-vessel ischaemia (P<0.0001). For women undergoing dobutamine stress, 5-year survival was 95, 89, and 86.6% for those with 0, 1, and 2-3 vessel ischaemia (P<0.0001). Exercising men had a 2.0-fold higher risk at every level of worsening ischaemia (P<0.0001). Significantly worsening cardiac survival was noted for the 1568 men undergoing dobutamine stress echocardiography (P<0.0001); no ischaemia was associated with 92% 5-year survival as compared with death rates of >/=16% for men with ischaemia on dobutamine stress echocardiography (P<0.0001).

CONCLUSION

Echocardiographic measures of inducible wall motion abnormalities and global and regional left ventricular function are highly predictive of long-term outcome for women and men alike.

Incremental prognostic power of single-photon emission computed tomographic myocardial perfusion imaging in patients with known or suspected coronary artery disease

Noninvasive stress testing provides prognostic information in patients who have suspected coronary artery disease, but limited data are available on the incremental value of myocardial perfusion testing in high-risk patients. We studied 3,275 patients who underwent cardiac catheterization and single-photon emission computed tomographic (SPECT) perfusion imaging. Median follow-up was 3.1 years for death, cardiovascular death, and a composite of cardiovascular death or nonfatal myocardial infarction. Using Cox's proportional hazards regression models, we examined the relation of SPECT summed stress score (SSS) to each outcome. A 1-unit change in SSS was associated with increased risks of 4%, 7%, and 5% for death, cardiovascular death, and death or nonfatal myocardial infarction, respectively (all p <0.0001). To examine the prognostic utility of SPECT, after baseline adjustments, SSS and angiographic results provided incremental prognostic information for each outcome. Thus, SPECT SSS provides information beyond clinical and angiographic data in patients who have known or suspected coronary artery disease. This information may be useful for stratifying patients into multiple risk categories for future cardiovascular events and potentially guiding therapy.

Technetium 99m sestamibi myocardial perfusion imaging predicts clinical outcome in the community outpatient setting. The Nuclear Utility in the Community (NUC) Study

OBJECTIVES

The purpose of this study was to evaluate the prognostic value of community-based myocardial perfusion imaging (MPI) and to assess the incremental value of individual components of (99m)Tc-sestamibi single photon emission computed tomography (SPECT).

BACKGROUND

Although the most rapid growth of MPI has been in community outpatient laboratories, its prognostic value has not been validated in this setting.

METHOD

We prospectively followed 1,612 consecutive patients undergoing stress (99m)Tc-sestamibi SPECT in an outpatient community laboratory who experienced 71 hard events over 24 +/- 7 months (0.2% lost to follow-up).

RESULTS

Patients whose scans were normal incurred an annualized event rate of 0.4%, compared with 2.3% for those with abnormal scans (p < 0.0001). Subset analysis demonstrated comparable risk stratification for women and men, diabetics, patients with normal resting ECGs, and those referred for pharmacologic and exercise stress. After adjusting for pre-test variables, multivariable Cox regression analysis found the most potent independent components of MPI to be, in order of importance, transient ischemic dilation, extent of reversibility, post-stress ejection fraction, extent and severity of the stress perfusion defect, and the overall test result (normal or abnormal). Each 1% decrement of ejection fraction predicted a 3% increase in risk (p = 0.0009). Post-MPI angiography and revascularization increased commensurate with the extent and severity of MPI result.

CONCLUSIONS

The prognostic value of perfusion imaging is portable and transferable to the outpatient community setting, with multiple components of MPI providing incremental prognostic information.

Rest perfusion defects in patients with no history of myocardial infarction predict the presence of a critical coronary artery stenosis

BACKGROUND

The rest/stress sequence in myocardial perfusion single photon emission computed tomography (SPECT) (MPS) permits evaluation of rest images before stress testing, allowing the identification of unexpected perfusion defects (PDs). We sought to study the angiographic correlates of these resting PDs.

METHODS AND RESULTS

This study comprised 139 consecutive patients with no history of myocardial infarction referred for MPS whose stress test was canceled because of the observation of unexpected resting PDs (rest group). Of these, 60 patients (43.2%) were referred for angiography after MPS (6.0 +/- 11.5 days). Angiographic referral rates and results were compared with those of a diagnostic population (n = 3565) who demonstrated stress-induced PDs (stress group) on rest/stress MPS. The mean age in the rest group was 73 +/- 12.5 years, and 73% were men. The frequency of referral for angiography was higher in the rest group (43.2% vs 19.8%, P <.0001). In addition, the rest group more frequently had significant coronary artery disease (CAD) (>/=70%) (95% vs 80%, P =.008) and critical CAD (>/=90%) (80% vs 66%, P =.038).

CONCLUSION

The rest/stress sequence for MPS enables the identification of patients with unexpected resting PD, usually resulting from critical CAD, in whom unnecessary stress testing can be avoided.