Prediction of death and myocardial infarction by screening with exercise-thallium testing after coronary-artery-bypass grafting

Non-invasive Ischaemia Testing in Patients With Prior Coronary Artery Bypass Graft Surgery: Technical Challenges, Limitations, and Future Directions

Coronary artery bypass graft (CABG) surgery effectively relieves symptoms and improves outcomes. However, patients undergoing CABG surgery typically have advanced coronary atherosclerotic disease and remain at high risk for symptom recurrence and adverse events. Functional non-invasive testing for ischaemia is commonly used as a gatekeeper for invasive coronary and graft angiography, and for guiding subsequent revascularisation decisions. However, performing and interpreting non-invasive ischaemia testing in patients post CABG is challenging, irrespective of the imaging modality used. Multiple factors including advanced multi-vessel native vessel disease, variability in coronary hemodynamics post-surgery, differences in graft lengths and vasomotor properties, and complex myocardial scar morphology are only some of the pathophysiological mechanisms that complicate ischaemia evaluation in this patient population. Systematic assessment of the impact of these challenges in relation to each imaging modality may help optimize diagnostic test selection by incorporating clinical information and individual patient characteristics. At the same time, recent technological advances in cardiac imaging including improvements in image quality, wider availability of quantitative techniques for measuring myocardial blood flow and the introduction of artificial intelligence-based approaches for image analysis offer the opportunity to re-evaluate the value of ischaemia testing, providing new insights into the pathophysiological processes that determine outcomes in this patient population.

Utility of nuclear stress imaging in predicting long-term outcomes one-year post CABG Surgery

BACKGROUND

Early MPI after CABG is currently considered rarely appropriate in asymptomatic patients. This study aimed to identify prognostic value of nuclear stress-imaging post-CABG.

METHODS

This was a single center prospective study looking at long-term outcomes post-CABG. Per protocol participants underwent SPECT-MPI stress testing and coronary angiogram on the same day, 1-year following CABG. Defect size was semi-quantified. The primary outcomes were the composite of death and congestive heart failure.

RESULTS

Eighty-four participants underwent nuclear stress-imaging and angiography, with a median follow-up of 11.1 years. Three separate stress findings predicted the primary outcome: inability to reach stage 3 of a Bruce protocol (OR 7.3, CI 2.4-22.1, P < 0.001), LVEF < 45% (OR 4.0, CI 1.1-15.3, P = 0.041) and a moderate-large stress defect size (HR 2.31, CI 1.1-1.5, P = 0.04). These findings appear to be additive and strongest among patients who underwent exercise stress testing (HR 10.6, CI 3.6-30.6, P < 0.001). Graft disease was identified in 39 (46%) patients and compared to those individuals with no graft disease, did not predict long-term adverse outcomes (P = 0.29).

CONCLUSION

In clinically stable patients early after revascularization with CABG, SPECT-MPI can identify patients at higher risk of heart failure and death.

Cardiac Stress Testing After Coronary Revascularization

Unless prompted by symptoms or change in clinical status, the appropriate use criteria consider cardiac stress testing (CST) within 2 years of percutaneous coronary intervention (PCI) and 5 years of coronary artery bypass grafting (CABG) to be rarely appropriate. Little is known regarding use and yield of CST after PCI or CABG. We studied 39,648 patients treated with coronary revascularization (29,497 PCI; 10,151 CABG) between April 2004 and March 2012 in Alberta, Canada. Frequency of CST between 60 days and 2 years after revascularization was determined from linked provincial databases. Yield was defined as subsequent rates of coronary angiography and revascularization after CST. Post PCI, 14,195 (48.1%) patients underwent CST between 60 days and 2 years, while post CABG, 4,469 (44.0%) patients underwent CST. Compared with patients not undergoing CST, patients undergoing CST were more likely to be of younger age, reside in an urban area, have higher neighborhood median household income, but less medical comorbidities. Among PCI patients undergoing CST, 5.2% underwent subsequent coronary angiography, and 2.6% underwent repeat revascularization within 60 days of CST. Rates of coronary angiography and repeat revascularization post-CST among CABG patients were 3.6% and 1.1%, respectively. Approximately one-half of patients undergo CST within 2 years of PCI or CABG in Alberta, Canada. Yield of CST is low, with only 1 out of 38 tested post-PCI patients and 1 out of 91 tested post-CABG patients undergoing further revascularization. In conclusion, additional research is required to determine patients most likely to benefit from CST after revascularization.

Sex-Specific Association Between Coronary Artery Disease Severity and Myocardial Ischemia Induced by Mental Stress

OBJECTIVE

It is unclear whether mental stress-induced myocardial ischemia (MSIMI) is related to obstructive coronary artery disease (CAD). We examined this question and contrasted results with ischemia induced by conventional stress testing (CSIMI). Because women are more susceptible to ischemia without coronary obstruction than men, we examined sex differences.

METHODS

We studied 276 patients 61 years and younger with recent myocardial infarction. CAD severity was quantified using the log-transformed Gensini Score (lnGS) and the Sullivan Stenosis Score. Patients underwent myocardial perfusion imaging with mental stress (public speaking) and conventional (exercise or pharmacological) stress testing. MSIMI and CSIMI were defined as a new or worsening perfusion defect.

RESULTS

The prevalence of MSIMI was 15% in men and 20% in women. The median GS for patients with MSIMI was 65.0 in men and 28.5 in women. In logistic regression models adjusted for demographic and cardiovascular risk factors, CAD severity was associated with CSIMI in the full sample (odds ratio [OR] = 1.49, 95% [CI], 1.14-1.95, per 1-unit increase in lnGS), with no significant difference by sex. Although CAD severity was not associated with MSIMI in the entire sample, results differed by sex. CAD severity was associated with MSIMI among men (OR = 1.95, 95% CI, 1.13-3.36, per 1-unit increase in lnGS), but not among women (OR = 1.02, 95% CI, 0.74-1.42, p = .042 for interaction). Analysis using Sullivan Stenosis Score yielded similar results.

CONCLUSIONS

Findings suggest that CAD severity is related to MSIMI in men but not women. MSIMI in women may therefore be driven by alternative mechanisms such as coronary microvascular disease.

Hybrid coronary computed tomography angiography and positron emission tomography myocardial perfusion imaging in evaluation of recurrent symptoms after coronary artery bypass grafting

Aims

Recurrent chest pain after coronary artery bypass grafting (CABG) poses a diagnostic challenge. We hypothesized that combining anatomy of bypass grafts and native coronary arteries with ischaemia detection by hybrid imaging could be used to gain valuable and complementary information in patients with recurrent symptoms after CABG.

Methods and results

We analysed 36 consecutive patients (67 ± 9 years, 81% male) who had undergone hybrid imaging using coronary computed tomography angiography (CCTA) and [15O]H2O positron emission tomography (PET) myocardial perfusion imaging due to recurrent symptoms after CABG. Coronary tree and left ventricular myocardium were divided into three main territories, yielding a total of 108 coronary territories in 36 patients. The presence of obstructive (≥50%) stenosis and the patency of grafts were evaluated by CCTA, while myocardial ischaemia was assessed by quantitative adenosine-stress PET. Altogether 28 (78%) of the 36 study patients presented with matched PET/CCTA abnormalities. Forty-one coronary territories were supplied by non-obstructed bypass grafts or native coronary arteries (protected territory). However, 12 (29%) of these presented with a perfusion defect. In six cases, the perfusion defect involved myocardium distal to the graft-coronary anastomosis, as interpreted on the PET/CCTA fusion images. In turn, in 48 coronary territories the supplying artery was obstructed on CCTA (unprotected territory). Of these, 41 (85%, P < 0.001 vs. protected) presented with abnormal perfusion, involving myocardium distal to the anastomosis in 29 cases.

Conclusion

Hybrid imaging provides complementary information on the presence and localization of atherosclerotic lesions and myocardial perfusion abnormalities in symptomatic patients with previous CABG.

Prognostic value of normal positron emission tomography myocardial perfusion imaging in patients with known or suspected coronary artery disease: a meta-analysis

OBJECTIVE

Several studies have confirmed high diagnostic performance of positron emission tomography (PET) myocardial perfusion imaging (MPI) in patients with known or suspected coronary artery disease. However, whether the superior diagnostic accuracy could translate into improved mortality outcomes remains unknown. The aim of this study was to define the prognostic value of normal PET MPI.

METHODS

PubMed and EMBASE were searched to identify related studies up to June 2016. All studies using PET MPI to evaluate subjects with known or suspected coronary artery disease and providing absolute number of patients with a negative test and primary data on clinical outcomes with a follow-up time ≥3 months were included for analysis.

RESULTS

The search yielded 11 studies comprising 20,471 patients for final analysis. The negative-predictive value (NPV) for cardiac death, all-cause death and major adverse cardiovascular events (MACE) were 98.80% [95% confidence interval (CI), 97.64%-99.39%], 94.89% (95% CI: 92.99-96.30%) and 90.26% (95% CI: 78.01-96.03%), over 36.9 months of follow-up for cardiac death, over 26.8 months for all-cause death and 35.7 months for MACE. The corresponding annualized event rates were 0.39%, 2.29% and 3.27%, respectively. In subgroup analyses of different imaging analysis methods for PET MPI, studies using perfusion abnormity had a similar NPV as compared with those using coronary flow reserve (98.46% vs 98.86%, p-value = NS), with a corresponding annualized event rate after negative tests (equal to 1 - NPV) as 0.45% and 0.42%, respectively.

CONCLUSION

Normal PET has a high NPV for cardiac death, MACE and all-cause mortality. Different indexes used for PET imaging analysis have a comparable prognostic value. Advances in knowledge: A normal PET MPI conferred a very low risk of cardiac death of 0.39% per year, which is close to that of a normal aged-matched population.

Budget impact of applying appropriateness criteria for myocardial perfusion scintigraphy: The perspective of a developing country

Myocardial perfusion imaging is widely used for the risk stratification of coronary artery disease. In view of its cost, besides radiation issues, judicious evaluation of the appropriateness of its indications is essential to prevent an unnecessary economic burden on the health system. We evaluated, at a tertiary-care, public Brazilian hospital, the appropriateness of myocardial perfusion scintigraphy indications, and estimated the budget impact of applying appropriateness criteria. An observational, cross-sectional study of 190 patients with suspected or known coronary artery disease referred for myocardial perfusion imaging was conducted. The appropriateness of myocardial perfusion imaging indications was evaluated with the Appropriate Use Criteria for Cardiac Radionuclide Imaging published in 2009. Budget impact analysis was performed with a deterministic model. The prevalence of appropriate requests was 78%; of inappropriate indications, 12%; and of uncertain indications, 10%. Budget impact analysis showed that the use of appropriateness criteria, applied to the population referred to myocardial perfusion scintigraphy within 1 year, could generate savings of $ 64,252.04 dollars. The 12% inappropriate requests for myocardial perfusion scintigraphy at a tertiary-care hospital suggest that a reappraisal of MPI indications is needed. Budget impact analysis estimated resource savings of 18.6% with the establishment of appropriateness criteria for MPI.

Prediction of all-cause mortality from gated-SPECT global myocardial wall thickening: comparison with ejection fraction and global longitudinal 2D-strain

BACKGROUND

The aim of this study was to assess the correlation between global wall thickening (GWT) obtained by gated-single photon emission computed tomography (SPECT) and echocardiographic measures [ejection fraction (EF), global longitudinal strain (GLS), and strain rate (GLSR)] and to compare their prognostic value for all-cause mortality.

METHODS AND RESULTS

Seventy-four patients with referral for dipyridamole myocardial perfusion SPECT were prospectively included and underwent transthoracic echocardiography to measure left ventricular EF, GLS, and GLSR. The strongest correlation with GWT was for EF (R = 0.63, P < .001), followed by GLSR (R = -0.57, P < .001) and GLS (R = -0.53, P < .001). There were ten deaths over a period of 14.6 ± 5.7 months. Using the multivariate Cox analysis, summed stress score (HR 1.108; P = .023), EF (HR 1.01, P = .031), GLS (HR 1.593, P = .001), and GWT (HR 0.898, P = .034) remained independent predictors of mortality. Mean survival rate evaluated by Kaplan-Meier analysis was longer in patients with GWT ≥ 24% (21.9 ± 0.6 months) than those with GWT < 24% (13.6 ± 2.7 months; P < .001).

CONCLUSIONS

GWT assessed is a highly sensitive tool to detect early myocardial systolic dysfunction and may bring additional prognostic information.

Prognostic value of stress imaging after revascularization: a systematic review of stress echocardiography and stress nuclear imaging

BACKGROUND

Risk assessment may be important in patients being considered for repeat revascularization after prior coronary intervention or surgery. We sought the prognostic value of radionuclide stress myocardial perfusion imaging or echocardiography among patients with previous revascularization.

METHODS

Studies on the outcomes of stress imaging tests after revascularization were selected from an electronic search if they reported the odds or hazard ratio (HR) of an abnormal stress test in the prediction of mortality (cardiac or total), hard cardiac events (cardiac death and myocardial infarction [MI]), total hard events (total mortality and MI]), or overall events (cardiac death, MI, and repeat revascularization).

RESULTS

In 29 studies (12,874 patients, 63 ± 3 years, 80% men), an abnormal test result was associated with hard cardiac events (HR 1.2, 95% CI 1.1-1.3), cardiac mortality (HR 5.8, 95% CI 0.8-10.8), total mortality (HR 2.2, 95% CI 1.3-3.1), total hard events(HR 2.4, 95% CI 1.4-3.3), and overall events (HR 1.2, 95% CI 1.1-1.3). The nature of the end point was not associated with differences in the prediction of events, but the type of revascularization showed a significant association with outcome, with percutaneous intervention portending a worse outcome. Age and the timing of the stress imaging postrevascularization were inversely associated with survival. Gender, length of follow-up after testing, symptom status, past infarction, and risk factor status did not explain interstudy heterogeneity.

CONCLUSIONS

In patients with previous revascularization, abnormal results at stress echocardiography or radionuclide myocardial perfusion imaging are predictive of subsequent events, with age, type of revascularization, and the timing of the stress imaging after revascularization being important sources of heterogeneity between studies.

A combination of anatomical and functional evaluations improves the prediction of cardiac event in patients with coronary artery bypass

OBJECTIVE

To study the usefulness of combined risk stratification of coronary CT angiography (CTA) and myocardial perfusion imaging (MPI) in patients with previous coronary-artery-bypass grafting (CABG).

DESIGN

A retrospective, observational, single centre study.

SETTING AND PATIENTS

204 patients (84.3% men, mean age 68.7±7.6) undergoing CTA and MPI.

MAIN OUTCOME MEASURES

CTA defined unprotected coronary territories (UCT; 0, 1, 2 or 3) by evaluating the number of significant stenoses which were defined as the left main trunk ≥50% diameter stenosis, other native vessel stenosis ≥70% or graft stenosis ≥70%. Using a cut-off value with receiver-operating characteristics analysis, all patients were divided into four groups: group A (UCT=0, summed stress score (SSS)<4), group B (UCT≥1, SSS<4), group C (UCT=0, SSS≥4) and group D (UCT≥1, SSS≥4).

RESULTS

Cardiac events, as a composite end point including cardiac death, non-fatal myocardial infarction, unstable angina requiring revascularisation and heart-failure hospitalisation, were observed in 27 patients for a median follow-up of 27.5 months. The annual event rates were 1.1%, 2%, 5.7% and 12.9% of patients in groups A, B, C and D, respectively (log rank p value <0.0001). Adding UCT or SSS to a model with significant clinical factors including left ventricular ejection fraction, time since CABG and Euro SCORE II improved the prediction of events, while adding UCT and SSS to the model improved it greatly with increasing C-index, net reclassification improvement and integrated discrimination improvement.

CONCLUSIONS

The combination of anatomical and functional evaluations non-invasively enhances the predictive accuracy of cardiac events in patients with CABG.

Identification of therapeutic benefit from revascularization in patients with left ventricular systolic dysfunction: inducible ischemia versus hibernating myocardium

BACKGROUND

Although the recent surgical treatment of ischemic heart failure substudy reported that revascularization of viable myocardium did not improve survival, these results were limited by the viability imaging technique used and the lack of inducible ischemia information. We examined the relative impact of stress-rest rubidium-82/F-18 fluorodeoxyglucose positron emission tomography identified ischemia, scar, and hibernating myocardium on the survival benefit associated with revascularization in patients with systolic dysfunction.

METHODS AND RESULTS

The extent of perfusion defects and metabolism-perfusion mismatch was measured with an automated quantitative method in 648 consecutive patients (age, 65±12 years; 23% women; mean left ventricular ejection fraction, 31±12%) undergoing positron emission tomography. Follow-up time began at 92 days (to avoid waiting-time bias); deaths before 92 days were excluded from the analysis. During a mean follow-up of 2.8±1.2 years, 165 deaths (27.5%) occurred. Cox proportional hazards modeling was used to adjust for potential confounders, including a propensity score to adjust for nonrandomized treatment allocation. Early revascularization was performed within 92 days of positron emission tomography in 199 patients (33%). Hibernating myocardium, ischemic myocardium, and scarred myocardium were associated with all-cause death (P=0.0015, 0.0038, and 0.0010, respectively). An interaction between treatment and hibernating myocardium was present such that early revascularization in the setting of significant hibernating myocardium was associated with improved survival compared with medical therapy, especially when the extent of viability exceeded 10% of the myocardium.

CONCLUSIONS

Among patients with ischemic cardiomyopathy, hibernating, but not ischemic, myocardium identifies which patients may accrue a survival benefit with revascularization versus medical therapy.

Population-based study of the use of cardiac stress imaging and referral for coronary angiography and repeated revascularization after coronary artery bypass graft surgery

OBJECTIVE

To assess stress single-photon emission computed tomography (SPECT) and stress echocardiography use after coronary artery bypass grafting (CABG) and their effect on referral for coronary angiography and revascularization.

PATIENTS AND METHODS

The referral, timing, and results of stress imaging after CABG; referral for coronary angiography and revascularization; and all-cause mortality were assessed in this longitudinal, population-based, retrospective study of 1138 Olmsted County, Minnesota, patients undergoing CABG between January 1, 1993, and December 31, 2003.

RESULTS

A total of 570 patients (50.1%) underwent a stress imaging study (341 SPECT and 229 echocardiography) during the study period. Of the 1138 patients, 372 (32.7%) were referred for coronary angiography, and 144 of those patients (12.7%) underwent repeated revascularization (132 percutaneous revascularization and 12 CABG). The median interval between CABG and the index stress imaging study was 3.0 years (25th-75th percentile, 1.2-5.7 years). The results of 75.7% (258 of 341) of the stress SPECT studies and 70.7% (162 of 229) of the stress echocardiograms were abnormal. Seventy-six of 570 patients (13.3%) referred for stress imaging underwent coronary angiography within 180 days after the stress test. Repeated coronary revascularization was performed in 25 patients (4.4%) who underwent a stress imaging study within the preceding 180 days. The 5- and 10-year survival rates in the entire study cohort (83.5% and 65.1%, respectively) were not significantly different than predicted for the age- and sex-matched Minnesota population.

CONCLUSION

Half of this community-based population of patients with CABG underwent stress SPECT or echocardiography during median follow-up of 8.9 years. Despite that approximately 75% of the results of stress imaging studies were abnormal, subsequent referral for coronary angiography within 180 days was low (13.3%), and the yield for repeated revascularization was very low (4.4%).

Myocardial perfusion imaging in patients with a recent, normal exercise test

AIM: To investigate the added value of myocardial perfusion scintigraphy imaging (MPI) in consecutive patients with suspected coronary artery disease (CAD) and a recent, normal exercise electrocardiography (ECG).

METHODS: This study was a retrospective analysis of consecutive patients referred for MPI during a 2-year period from 2006-2007 at one clinic. All eligible patients were suspected of suffering from CAD, and had performed a satisfactory bicycle exercise test (i.e., peak heart rate > 85% of the expected, age-predicted maximum) within 6 mo of referral, their exercise ECG was had no signs of ischemia, there was no exercise-limiting angina, and no cardiac events occurred between the exercise test and referral. The patients subsequently underwent a standard 2-d, stress-rest exercise MPI. Ischemia was defined based on visual scoring supported by quantitative segmental analysis (i.e., sum of stress score > 3). The results of cardiac catheterization were analyzed, and clinical follow up was performed by review of electronic medical files.

RESULTS: A total of 56 patients fulfilled the eligibility criteria. Most patients had a low or intermediate ATPIII pre-test risk of CAD (6 patients had a high pre-test risk). The referral exercise test showed a mean Duke score of 5 (range: 2 to 11), which translated to a low post-exercise risk in 66% and intermediate risk in 34%. A total of seven patients were reported with ischemia by MPI. Three of these patients had high ATPIII pre-test risk scores. Six of these seven patients underwent cardiac catheterization, which showed significant stenosis in one patient with a high pre-test risk of CAD, and indeterminate lesions in three patients (two of whom had high pre-test risk scores). With MPI as a gate keeper for catheterization, no significant, epicardial stenosis was observed in any of the 50 patients (0%, 95% confidence interval 0.0 to 7.1) with low to intermediate pre-test risk of CAD and a negative exercise test. No cardiac events occurred in any patients within a median follow up period of > 1200 d.

CONCLUSION: The added diagnostic value of MPI in patients with low or intermediate risk of CAD and a recent, normal exercise test is marginal.

Utility of nuclear stress imaging for detecting coronary artery bypass graft disease

Background

The value of Single Photon Emission Computed Tomography stress myocardial perfusion imaging (SPECT-MPI) for detecting graft disease after coronary artery bypass surgery (CABG) has not been studied prospectively in an unselected cohort.

Methods

Radial Artery Versus Saphenous Vein Graft Study is a Veterans Affairs Cooperative Study to determine graft patency rates after CABG surgery. Seventy-nine participants agreed to SPECT-MPI within 24 hours of their coronary angiogram, one-year after CABG. The choice of the stress protocol was made at the discretion of the nuclear radiologist and was either a symptom-limited exercise test (n = 68) or an adenosine infusion (n = 11). The SPECT-MPI results were interpreted independent of the angiographic results and estimates of sensitivity, specificity and accuracy were based on the prediction of a graft stenosis of ≥70% on coronary angiogram.

Results

A significant stenosis was present in 38 (48%) of 79 patients and 56 (22%) of 251 grafts. In those stress tests with an optimal exercise heart rate response (>80% maximum predicted heart rate) (n = 26) sensitivity, specificity and accuracy of SPECT-MPI for predicting the graft stenosis was 77%, 69% and 73% respectively. With adenosine (n = 11) it was 75%, 57% and 64%, respectively. Among participants with a suboptimal exercise heart rate response, the sensitivity of SPECT-MPI for predicting a graft stenosis was <50%. The accuracy of SPECT-MPI for detecting graft disease did not vary significantly with ischemic territory.

Conclusions

Under optimal stress conditions, SPECT-MPI has a good sensitivity and accuracy for detecting graft disease in an unselected patient population 1 year post-CABG.

Non-invasive evaluation of internal thoracic artery anastomosed to the left anterior descending artery with 320-detector row computed tomography and adenosine thallium-201 myocardial perfusion scintigraphy

PURPOSE

We evaluated the relationship between internal thoracic artery (ITA) stenosis anastomosed to the left anterior descending artery (LAD) and the degree of LAD stenosis using 320-detector row computed tomography (320-ADCT) and adenosine thallium-201 myocardial perfusion scintigraphy (Tl-201-MPS).

METHODS

We included 101 patients who underwent coronary artery bypass grafting (CABG) using ITA grafts; 320-ADCT and adenosine Tl-201-MPS were performed 2-3 months after CABG. Clinical parameters, degree of LAD stenosis, and regional myocardial ischemia of the LAD territory were compared between patients without ITA stenosis (Group A) and with ITA stenosis (Group B).

RESULTS

Thirty patients (30%) had ≤75% LAD stenosis, and 9 patients (30%) showed significant ITA stenosis. Regional ischemia was noted in 23 patients (23%). There were no differences in clinical parameters between the 2 groups. Twenty-two patients (24%) in Group A and 8 patients (89%) in Group B had ≤75% LAD stenosis (P <0.002). No Group B patients had regional myocardial ischemia of the LAD territory.

CONCLUSION

We concluded that ≤75% LAD stenosis significantly influences ITA stenosis, without associated regional myocardial ischemia of the LAD territory. Non-invasive 320-ADCT and adenosine Tl-201-MPS for ITA evaluation may be useful for long-term follow-up of patients after CABG.

Prognostic value of treadmill exercise and dobutamine stress positron emission tomography

BACKGROUND

Although positron emission tomography (PET) is routinely performed using vasodilator stress, exercise and dobutamine stress are available alternatives. Evidence suggests that vasodilator PET myocardial perfusion imaging (MPI) has prognostic value, but the prognostic value of treadmill exercise and dobutamine PET MPI is unknown.

OBJECTIVE

To determine the potential prognostic value of nonvasodilator stress PET MPI.

METHODS

Patients underwent treadmill exercise or dobutamine PET MPI. Images were assessed qualitatively and semiquantitatively. PET results were categorized as normal (summed stress score [SSS] of less than 4), abnormal (SSS of 4 or greater) or inconclusive (SSS of less than 4 and submaximal peak stress heart rate). Patient follow-up (cardiac death, nonfatal myocardial infarction [MI] and/or late revascularization) was performed.

RESULTS

Of the 124 patients (mean follow-up period of 2.3+/-1.6 years), 46 patients (37%) had a normal study, 15 patients (12%) had an inconclusive study and 63 (51%) had an abnormal PET. Patients with a normal PET had no deaths or nonfatal MI. One patient with a normal PET underwent late revascularization (annual event rate of 1.7%). Patients with an abnormal PET had 15 cardiac events (one cardiac death, four nonfatal MIs and 10 late revascularizations), with an annual event rate of 13.0% (P=0.002).

CONCLUSIONS

Although small, the present study suggests that defects seen on PET myocardial perfusion, resulting from stressors (treadmill exercise and dobutamine) that increase myocardial oxygen demand, may have prognostic value.

Long-term effects of a multimodal behavioral intervention on myocardial perfusion--a randomized controlled trial

BACKGROUND

Recent advances in drug therapy question as to the additional impact behavioral interventions may have on the prognosis of patients with clinically stable coronary heart disease (CHD).

PURPOSE

The aim of the study was to evaluate the effects of a multimodal, behavioral intervention on myocardial perfusion (MP) and cardiac events, compared to standardized cardiologic care, in patients with stable CHD.

METHODS

Seventy-seven CHD patients (age 54.2 +/- 6.9 years, male 87%) were randomly assigned to a behavioral intervention plus standardized cardiologic care (INT, n = 39) or standardized cardiologic care alone (CO, n = 38). MP was assessed by (201)Thallium MP-scintigrams (SPECT) at baseline, after 2, 3, and 7 years, respectively. Subsequent cardiac events (MI, PCI, CABG) were assessed using the cardiologists' charts.

RESULTS

Sixty-five patients (84%) completed the study. In all patients, the course of MP was significantly better in INT analysis of variance (ANOVA group x time p = 0.001); this was also true for patients without subsequent PCI/CABG (ANOVA group x time p = 0.002). Incidence of cardiac events was significantly associated with INT (6 vs. 14; log rank test p = .047).

CONCLUSION

The study suggests additional long-term benefits of a behavioral intervention on myocardial perfusion and cardiac events in patients with stable CHD compared to standardized cardiologic care only.

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

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

Inducible ischemia and the risk of recurrent cardiovascular events in outpatients with stable coronary heart disease: the heart and soul study

BACKGROUND

Current guidelines do not recommend routine cardiac stress testing in patients with stable coronary heart disease (CHD) unless they report symptoms of angina. Our objective was to compare the prognosis of self-reported angina symptoms, inducible ischemia, or both in patients with stable CHD.

METHODS

We measured self-reported angina by questionnaire and inducible ischemia using treadmill stress echocardiography in 937 outpatients with stable CHD. We used Cox proportional hazard models, adjusted for traditional cardiovascular risk factors, to evaluate the independent association of angina and inducible ischemia with CHD events (myocardial infarction or CHD death) during a mean of 3.9 years of follow-up.

RESULTS

Of the study participants, 129 (14%) had angina alone, 188 (20%) had inducible ischemia alone, and 40 (4%) had both angina and ischemia. Recurrent CHD events occurred in 7% of participants without angina or inducible ischemia, 10% of those with angina alone, 21% of those with inducible ischemia alone, and 23% of those with both angina and inducible ischemia (P < .001). The presence of angina alone was not associated with recurrent CHD events (adjusted hazard ratio, 1.4; 95% confidence interval, 0.7-2.9) (P = .31). However, the presence of inducible ischemia without self-reported angina strongly predicted recurrent CHD events (adjusted hazard ratio, 2.2; 95% CI, 1.4-3.5) (P = .005).

CONCLUSIONS

We found that 24% of patients with stable CHD had inducible ischemia, and more than 80% of these patients did not report angina. The presence of inducible ischemia without self-reported angina is associated with a greater than 2-fold increased rate of recurrent CHD events.

Stress cardiac single-photon emission computed tomographic imaging late after coronary artery bypass surgery for risk stratification and estimation of time to cardiac events

OBJECTIVE

We assessed predictors and temporal characteristics of cardiac risk in patients undergoing stress single-photon emission computed tomography after coronary artery bypass grafting.

METHODS

Stress cardiac tomography was performed in 362 patients 5 years after coronary artery bypass grafting. Cardiac death and myocardial infarction were considered as events. Cox proportional hazards analysis was used to identify predictors of events and parametric survival analysis to predict time to events.

RESULTS

During a median follow-up of 27 months, 22 cardiac events occurred (6.1% cumulative event rate). At multivariable Cox analysis, ischemia at cardiac tomography (hazards ratio 3.7, 95% confidence interval 1.5-9.1; P = .004), and diabetes (hazards ratio 3.6, 95% confidence interval 1.5-8.5; P = .006) resulted in independent predictors of events. Event-free survival was 96% in patients with normal cardiac tomography, 86% in those with abnormal tomography without ischemia, and 70% in those with (log-rank 10.6, P for trend = .008). The parametric survival model revealed that the cardiac risk was greater for all time intervals and accelerated more over time in patients with ischemia than in those without (chi(2) 21.4, P < .0001). Patients without diabetes and normal cardiac tomography remained below a defined risk level (5%) for the entire follow-up period.

CONCLUSION

Stress cardiac tomography performed 5 years after coronary artery bypass grafting is useful to characterize the risk of cardiac events and its temporal variation. Parametric survival model estimates the predicted time to risk and the level of risk at specific time intervals after coronary artery bypass grafting.

Quantitative Measures of Electrocardiographic Left Ventricular Mass, Conduction, and Repolarization, and Long-Term Survival After Coronary Artery Bypass Grafting

Background— Quantitative ECG measures of left ventricular mass and repolarization predict outcome in population-based cohorts and patients with hypertension. We assessed the prognostic value of preoperative quantitative electrocardiography in patients who underwent isolated coronary artery bypass grafting.

Methods and Results— For 6 years we followed 8166 patients who underwent primary isolated coronary artery bypass grafting between 1990 and 2003, all of whom had routine preoperative ECGs. With use of specialized digital software, quantitative measures were recorded on ventricular rate, P duration, PR interval, QRS duration, QT interval, QRS axis, Sokolow-Lyon and Cornell voltages, and ST-segment depression and slope. There were 1516 deaths. After adjustment for age, gender, clinical characteristics, left ventricular ejection fraction, and other confounders, death was independently predicted by ventricular rate (adjusted hazard ratio [AHR] for 90 versus 60 beats per minute, 1.34; 95% confidence interval [CI], 1.21 to 1.50; P <.0001), PR interval (AHR for 200 versus 150 ms, 1.05; 95% CI, 1.00 to 1.10; P <.0001), QRS duration (AHR for 120 versus 80 ms, 1.24; 95% CI, 1.07 to 1.44; P <.0001), Sokolow-Lyon voltage (AHR for 3.5 versus 1.5 mV, 1.18; 95% CI, 1.05 to 1.31; P <.0001), and ST-segment slope (AHR for −0.1 versus 0 mV, 1.16; 95% CI, 1.02 to 1.31; P <.0001). We derived a quantitative ECG score and demonstrated that, with the exception of age, it was the most powerful predictor of long-term death.

Conclusions— Quantitative ECG measures of left ventricular rate, mass, and repolarization are predictive of mortality among patients who underwent isolated coronary artery bypass grafting. These findings suggest that quantitative electrocardiography may be valuable for risk stratification in patients with severe coronary artery disease.

Evidence based medicine: role of multidetector CT in the follow-up of patients receiving coronary artery bypass graft

PURPOSE

The aim of this study was to define the role of multidetector computed tomography (MDCT) in the follow-up assessment of patients undergoing coronary artery bypass grafting (CABG) using an evidence-based medicine (EBM) approach.

MATERIALS AND METHODS

We performed a literature search of the most reputable studies published in the period 1990-2005 on the clinical follow-up of patients after myocardial revascularisation by CABG. Relevant studies were ranked according to levels of evidence using EBM criteria. A similar search was also conducted on the Internet to identify and review the guidelines posted by the major international scientific societies.

RESULTS

A total of 29 papers meeting the basic reliability requirements of EBM were identified. The reported sensitivity and specificity for electrocardiogram (ECG) testing, stress echocardiography and radionuclide myocardial perfusion imaging were 45% and 82%, 86% and 90%, and 68% and 84%, respectively. All 16 CT studies (one retrospective, the remaining prospective) were validation studies comparing MDCT with conventional coronary angiography. The total number of patients and graft segments studied were 705 and 1,974, respectively. The total number of assessable graft segments were 62%-100%, with a sensitivity and specificity of 75%-100% and 76.9%-100%, respectively.

CONCLUSIONS

The applications of MDCT in the follow-up assessment of patients after CABG are derived from indirect evidence only. The efficacy of the method should be evaluated in randomised clinical trials comparing MDCT not only with conventional coronary angiography but also with other noninvasive stress imaging methods. On the basis of the clinical evidence reported in the literature, the indications for the use of MDCT are still limited. In our view, the completion of such randomised trials combined with the development of new-generation scanners is required to correctly define the role of MDCT in the follow-up assessment of patients who have undergone CABG.

The effect of myocardial surgical revascularization on left ventricular late potentials

BACKGROUND

The presence of ventricular late potentials (LP) is an important indicator for the development of ventricular tachyarrhythmias due to ischemic heart disease. The effect of myocardial revascularization on LP has remained controversial. The purpose of this study was to determine whether complete myocardial surgical revascularization (CABG) documented by myocardial perfusion scintigraphy might alter the substrate responsible for LP.

METHODS

Prospectively, enrolled patients undergoing elective CABG were evaluated with thallium-201 myocardial perfusion scintigraphy and signal- averaged ECG pre- and postoperatively. SAECG recordings were obtained serially: before, 48-72 hours and 3 months after CABG. LPS were defined as positive if SAECG met at least two of Gomes criteria. Scintigraphies were performed pre- and 3 months postoperatively for determination of the success of revascularization. Changes observed in SAECG recordings after CABG were compared between those with and without successful revascularization.

RESULTS

CABG resulted in successful revascularization in 23 patients and was unsuccessful in 17 (no change or deterioration of the perfusion defects). Preoperative SAECG values were not different between groups except for RMS values. The incidence of LP decreased significantly postoperatively in patients with improved myocardial perfusion, whereas there were no changes in patients who did not have postoperative perfusion improvement (McNemar test, P < 0.05).

CONCLUSIONS

LPs disappear following the elimination of myocardial ischemia by complete surgical revascularization. Persistence of ischemia following CABG usually results in the persistence of late potentials. The incidence of ventricular arrhythmias is expected to be unchanged in these patients and they should be reevaluated for reinterventions.

What is the Prognostic Value of Myocardial Perfusion Imaging Using Rubidium-82 Positron Emission Tomography?

OBJECTIVES

The objective was to determine the prognostic value of rubidium-82 (82Rb) positron emission tomography (PET) myocardial perfusion imaging (MPI).

BACKGROUND

82Rb PET MPI accurately diagnoses coronary artery disease (CAD). However, there are limited data evaluating its prognostic value.

METHODS

Follow-up (3.1 +/- 0.9 years) was obtained in 367 patients who underwent dipyridamole 82Rb PET MPI. Patients were divided into groups based on their summed stress score (SSS): group I, normal (<4); group II, mild (4 to 7); and group III, moderate (8 to 11) to severe (> or =12).

RESULTS

There were significant differences among patients in the 3 SSS groups for hard events (cardiac death and myocardial infarction [MI]) (p < 0.001) and total cardiac events (hard events, revascularization and hospitalization) (p < 0.001). The annual hard events rates were 0.4%, 2.3%, and 7.0% in the normal, mild, and moderate-severe groups, respectively. In adjusted survival models, 82Rb PET SSS was the strongest predictor of total cardiac events and a significant predictor of hard events. Among patients referred for PET after 99mTc single-photon emission computed tomography, the annual total event rate was higher with abnormal versus normal SSS on PET (15.2% vs. 1.3%, p < 0.001). In patients with obesity, the annual total event rate was 11.1% with an abnormal scan and 1.5% with a normal scan (p < 0.001).

CONCLUSIONS

This study shows that 82Rb PET MPI has significant prognostic value for predicting cardiac events, including death and MI. It also seems to have prognostic value in patients whose diagnosis remains uncertain after single-photon emission computed tomography MPI and in obese patients. The prognostic value of PET MPI may improve the management of cardiac patients.

Disruption of graft endothelium correlates with early failure after off-pump coronary artery bypass surgery

BACKGROUND

Saphenous vein graft failure after coronary artery bypass surgery may be as high as 5% to 10% in the first postoperative week. We hypothesized that identifying damage sustained by saphenous vein endothelium before grafting predicts early graft attrition after off-pump coronary artery bypass graft surgery.

METHODS

Intraoperative graft flow, platelet function, and endothelial integrity were analyzed in 125 patients undergoing off-pump coronary artery bypass graft surgery. Endothelial integrity was assessed in an excess vein segment from each graft using immunohistochemistry (CD31 staining). Platelet function was monitored just before and immediately after revascularization and on postoperative days 1 and 3 using whole blood aggregometry, thrombelastography, and platelet activated clotting time. Platelet activation was monitored using flow cytometry. Intraoperative conduit blood flow, measured by transit time ultrasonography, was used to detect and rectify anastomotic problems. Early graft patency was determined on postoperative day 5 using gated multichannel computed tomography angiography.

RESULTS

In 106 patients undergoing postoperative computed tomography evaluation, 10 vein grafts in 10 patients were discovered to have developed early thrombosis, representing 4% (10 of 217) of all vein grafts. Endothelial integrity was 10.75% +/- 17.56% in 10 grafts that failed early compared with 51.45% +/- 36.29% in patent grafts (p = 0.04). Perioperative platelet function and graft flow did not differ significantly between the two groups.

CONCLUSIONS

Although endothelial disruption predicts early failure of bypass grafts, the importance of a hypercoaguable state and low graft flow as a cause of early graft thrombosis after off-pump coronary artery bypass graft surgery was not supported by our preliminary results. A means to assess, prevent, and treat intraoperative vein graft damage will likely improve early graft patency.

Use of Stress Testing Early After Coronary Artery Bypass Graft Surgery

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

Usefulness of exercise myocardial scintigraphy in multivessel coronary disease after incomplete revascularization with coronary stenting

The aim of this prospective study was to evaluate the prognostic value of exercise myocardial scintigraphy in patients who undergo incomplete revascularization with percutaneous coronary stenting. In 322 consecutive patients (mean age 61 +/- 10 years), exercise technetium-99m-tetrofosmin single-photon emission computed tomography scintigraphy was prospectively performed 4 to 6 months after an incomplete revascularization procedure. Follow-up lasted < or = 84 months (median 33). Patients with normal findings were at low risk of cardiac events compared with patients with mildly abnormal and severely abnormal findings (yearly event rate 1.5% vs 5.1% and 8.5%, respectively, p < 0.01). A significant difference was observed in hard, soft, and composite event-free survival among patients with normal, mildly abnormal, and severely abnormal findings (p < 0.01, p < 0.03, and p < 0.01, respectively). Nuclear data provided significant incremental prognostic value for cardiac events compared with the clinical, angiographic, and exercise test findings. In conclusion, in patients with incomplete revascularization procedures, exercise myocardial scintigraphy provides significant independent information concerning the subsequent risk of cardiac events, with an annualized event rate of < 2% for patients with normal scan findings. Myocardial scintigraphy is able to provide incremental prognostic information after adjusting for clinical, angiographic, and exercise variables.

Myocardial viability testing and the effect of early intervention in patients with advanced left ventricular systolic dysfunction

BACKGROUND

The clinical value of revascularization and other procedures in patients with severe systolic heart failure is unclear. It has been suggested that assessing ischemia and viability by positron emission tomography (PET) with fluorodeoxyglucose (FDG) imaging may identify patients for whom revascularization may lead to improved survival. We performed a propensity analysis to determine whether there might be a survival advantage from revascularization.

METHODS AND RESULTS

We analyzed the survival of 765 consecutive patients (age 64+/-11 years, 80% men) with advanced left ventricular systolic dysfunction (ejection fraction < or =35%) and without significant valvular heart disease who underwent PET/FDG study at the Cleveland Clinic between 1997 and 2002. Early intervention was defined as any cardiac intervention (surgical or percutaneous) within the first 6 months of the PET/FDG study. In the entire cohort, 230 patients (30%) underwent early intervention (188 [25%] had open heart surgery, most commonly coronary artery bypass grafting, and 42 [5%] had percutaneous revascularization); 535 (70%) were treated medically. Using 39 demographic, clinical and PET/FDG variables, we were able to propensity-match 153 of the 230 patients with 153 patients who did not undergo early intervention. Among the propensity-matched group, there were 84 deaths during a median of 3 years follow-up. Early intervention was associated with a markedly lower risk of death (3-year mortality rate of 15% versus 35%, propensity adjusted hazard ratio 0.52, 95% CI 0.33 to 0.81, P=0.0004).

CONCLUSIONS

Among systolic heart failure patients referred for PET/FDG, early intervention may be associated with improved survival irrespective of the degree of viability.

A New Anatomic Score for Prognosis After Cardiac Catheterization in Patients with Previous Bypass Surgery

OBJECTIVES

The purpose of this study was to determine the value of a new anatomic score for prognosis after diagnostic catheterization in patients with previous coronary artery bypass grafting (CABG).

BACKGROUND

Previous CABG patients comprise a growing proportion of patients with coronary artery disease (CAD). Whereas prognostic scores are available to adjust for native CAD, there are no comparable scores for patients with previous CABG.

METHODS

We studied 3,178 previous CABG patients (2,729 in a training set) who underwent cardiac catheterization. With a Cox model to develop relative weights in the training set, we created a graft index that adjusted native anatomy for territories with grafts free of significant (> or =75%) stenoses. Scaling the regression coefficients by the maximum coefficient created an index ranging from 0 to 100, where 100 was three-vessel CAD with no patent grafts.

RESULTS

The graft index was significantly associated with all-cause death (chi-square = 121.9, p < 0.001). In combined models, the index was more strongly associated with all-cause death than either number of diseased vessels (chi-square = 68.0 and 1.7, respectively) or the Duke CAD index (chi-square = 54.3 and 9.5, respectively). In models for death using an independent validation set, the index was also associated more strongly than either native disease descriptors. In a model including other clinical variables, the graft index remained significantly associated with all-cause death (chi-square = 40.1, p < 0.001).

CONCLUSIONS

For previous CABG patients, the Duke graft index was significantly more associated with prognosis than native anatomy alone and quantifies the effect of patent grafts on survival. This tool has the potential to help determine prognosis and inform the referral of post-CABG patients to repeat revascularization procedures.

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.

Prediction of death or myocardial infarction by exercise single photon emission computed tomography perfusion scintigraphy in patients who have had recent coronary artery stenting

BACKGROUND

Although practice guidelines do not recommend routine exercise testing of patients after coronary stenting, several small studies have suggested that stress myocardial perfusion imaging can provide prognostic information about future adverse cardiac events. We sought to determine if exercise nuclear testing provides independent prognostic information in patients after coronary stenting.

METHODS

We analyzed the outcomes of 370 patients who underwent dual isotope exercise nuclear scintigraphy at least 1 month after coronary stenting and had testing between April 1996 and May 2002. Patients were classified according to presence or absence of any ischemia. The primary endpoint was all-cause mortality or myocardial infarction (MI) during a median of 30 months (range 6-59) of follow-up.

RESULTS

There were 86 patients (23%) who had ischemia. Major events--death or MI--occurred in 62 patients including 22 deaths. Among patients with no ischemia, the 30-month event rate was 9.1%, whereas among patients with ischemia, the event rate was 17.0% (P = .001). After adjusting for age, sex, standard cardiac risk factors, cardiac history, left ventricular ejection fraction, angiographic findings, procedural variables, exercise capacity, and heart-rate dynamics, the presence of scintigraphic evidence of ischemia predicted death or MI (adjusted hazard ratio 2.08, 95% CI 1.21-3.56, P = .008). The presence of ischemia similarly predicted events in asymptomatic patients (adjusted hazard ratio 2.19, 95% CI 1.17-4.11, P = .015).

CONCLUSIONS

In patients with recent coronary stent placement, reversible nuclear perfusion defects independently predicted risk of death or MI.

Prognostic value of dobutamine stress echocardiography in patients with previous coronary revascularisation

OBJECTIVE

To assess the prognostic value of dobutamine stress echocardiography (DSE) in patients with previous myocardial revascularisation.

DESIGN

Prospective study.

SETTING

Tertiary referral centre in Rotterdam, the Netherlands.

PATIENTS

332 consecutive patients with previous percutaneous or surgical coronary revascularisation underwent DSE. Follow up was successful for 331 (99.7%) patients. Thirty eight patients who underwent early revascularisation (<or= 3 months) after the test were excluded from analysis.

MAIN OUTCOME MEASURES

Cox proportional hazards regression models were used to identify independent predictors of the composite of cardiac events (cardiac death, non-fatal myocardial infarction, and late revascularisation).

RESULTS

During a mean (SD) of 24 (20) months, 37 (13%) patients died and 89 (30%) had at least one cardiac event (21 (7%) cardiac deaths, 11 (4%) non-fatal myocardial infarctions, and 68 (23%) late revascularisations). In multivariate analysis of clinical data, independent predictors of late cardiac events were hypertension (hazard ratio (HR) 1.7, 95% confidence interval (CI) 1.1 to 2.6) and congestive heart failure (HR 2.1, 95% CI 1.3 to 3.2). Reversible wall motion abnormalities (ischaemia) on DSE were incrementally predictive of cardiac events (HR 2.1, 95% CI 1.3 to 3.2).

CONCLUSIONS

Myocardial ischaemia during DSE is independently predictive of cardiac events among patients with previous myocardial revascularisation, after controlling for clinical data.