Electrocardiographic Stress Testing Research Articles

Medical examinations of professional and amateur athletes at a sports medicine clinic. Insights from a sports medicine specialist and cardiologist.

In 2019, three regulations of the Minister of Health regarding sports medicine examinations in children, adolescents and young athletes came into force. The publication presents in detail the current scope of tests and the frequency of required medical examinations necessary to obtain medical certificates qualify- ing patients to practice sports. The publication also presents the Regulation of the Minister of Health on the required qualifications of doctors authorized to issue medical certificates to athletes. It is very important to properly assess the health of potential and current athletes to ensure their safety while participating in sports competitions. There are diseases that increase the risk of sudden cardiac death which doctors should keep in mind when qualifying athletes for competition. The publication draws attention to the underestimated role of echocardiography and electrocardiographic stress testing.

Effects of nordic walking training on gait and exercise tolerance in male ischemic heart disease patients.

This technique-focused observational study explores the impact of a 6-week Nordic Walking (NW) program on physiological and biomechanical aspects in ischemic heart disease (IHD) patients. Twelve male IHD patients (66.2 ± 5.2years, 12.2 ± 7.5years of disease duration) were evaluated pre- and post-training for (i) gait parameters, (ii) exercise tolerance using electrocardiographic (ECG) stress test, (iii) a 6-min walk test (6MWT). The NW training, adhering to IHD patient guidelines, involved a 100-m walk at a self-selected, preferred speed without sticks, with classic NW sticks and mechatronic sticks. A mechatronic measuring system, specifically engineered for measuring, diagnosing and monitoring the patient's gait, was integrated into mechatronic sticks. Post-training, significant enhancements were observed in ECG stress test duration, metabolic equivalency, and 6MWT distance, irrespective of the stick type. However, no significant changes were noted in spatiotemporal parameters concerning the measured side, stick utilisation, or type. The results suggest that NW training boosts exercise capacity and refines gait mechanics in male IHD patients. However, the improvement in exercise capacity was not linked to changes in gait mechanics from NW training but rather to the movement during NW gait. Hence, the key to enhancing exercise capacity in IHD patients is the movement during NW gait, not the quality of gait mechanics.

Rethinking False Positive Exercise Electrocardiographic Stress Tests by Assessing Coronary Microvascular Function

BackgroundExercise electrocardiographic stress testing (EST) has historically been validated against the demonstration of obstructive coronary artery disease. However, myocardial ischemia can occur because of coronary microvascular dysfunction (CMD) in the absence of obstructive coronary artery disease. ObjectivesThe aim of this study was to assess the specificity of EST to detect an ischemic substrate against the reference standard of coronary endothelium-independent and endothelium-dependent microvascular function in patients with angina with nonobstructive coronary arteries (ANOCA). MethodsPatients with ANOCA underwent invasive coronary physiological assessment using adenosine and acetylcholine. CMD was defined as impaired endothelium-independent and/or endothelium-dependent function. EST was performed using a standard Bruce treadmill protocol, with ischemia defined as the appearance of ≥0.1-mV ST-segment depression 80 ms from the J-point on electrocardiography. The study was powered to detect specificity of ≥91%. ResultsA total of 102 patients were enrolled (65% women, mean age 60 ± 8 years). Thirty-two patients developed ischemia (ischemic group) during EST, whereas 70 patients did not (nonischemic group); both groups were phenotypically similar. Ischemia during EST was 100% specific for CMD. Acetylcholine flow reserve was the strongest predictor of ischemia during exercise. Using endothelium-independent and endothelium-dependent microvascular dysfunction as the reference standard, the false positive rate of EST dropped to 0%. ConclusionsIn patients with ANOCA, ischemia on EST was highly specific of an underlying ischemic substrate. These findings challenge the traditional belief that EST has a high false positive rate.

Cardiotoxicity from Capecitabine Chemotherapy: Prospective Study of Incidence at Rest and During Physical Exercise.

BackgroundPhysical activity may increase the risk of cardiotoxicity (myocardial ischemia, major arrhythmias) of 5-Fluorouracil, but this risk has never been investigated for its prodrug capecitabine.Patients and MethodsOne hundred and ninety-two consecutive patients undergoing capecitabine chemotherapy from December 1, 2010 through July 31, 2016 were prospectively evaluated. The baseline evaluation included electrocardiography (ECG) and echocardiography (2DE); a follow-up evaluation, including ECG and exercise stress testing (2DE in case of ECG abnormalities), was done after ≥10 days of treatment. Cardiotoxicity was suspected from ischemic ECG changes, new kinetic abnormalities at 2DE, Lown classification ≥2 ventricular arrhythmia, symptomatic arrhythmias, or positive stress test, and confirmed by a negative stress test after capecitabine washout.ResultsCardiotoxicity was diagnosed in 32 patients (16.7%): six at rest and 26 during exercise. All 32 patients had ECG abnormalities: ST-segment changes (24 patients), negative T-waves (2) and/or arrhythmias: ventricular arrhythmias (14 cases), supraventricular tachycardia (2), complete heart block (1). Eight patients had typical symptoms, 6 had atypical symptoms, 1 had syncope, 17 (53%) were asymptomatic. Cardiotoxicity was more common in patients with atypical symptoms during daily life (OR = 15.7) and in those on a therapeutic schedule of 5 days/week (OR = 9.44).ConclusionCapecitabine cardiotoxicity is frequent, and often elicited by physical effort. Oncologists, cardiologists, and general practitioners should be aware of this risk. Active cardiotoxicity surveillance with ECG (and echocardiogram and/or stress testing in suspected cases) during therapy is recommended.Clinical Trials registration numberCRO-2010-17.

Abstract 10214: Stress Testing Prior to Abdominal Aortic Aneurysm Repair: What is Our Return on Investment?

Introduction: The use of stress testing prior to abdominal aortic aneurysm (AAA) repair is highly variable. We examined the financial implications of this variation and its impact on postoperative cardiac events. Methods: We studied patients who underwent elective endovascular (EVAR) or open AAA repair at Vascular Quality Initiative participating centers from 2015–2019. We grouped centers into quintiles by their frequency of preoperative stress testing. We calculated rates of major adverse cardiovascular events (MACE), a composite of in-hospital myocardial infarction, stroke, heart failure, or death, for each quintile. We applied the charges for electrocardiographic, echocardiographic, and nuclear stress tests at our institution in 2019 to the study population to calculate expected charges per 1,000 patients. Results: We studied 27,978 patients who underwent EVAR (mean age: 73.5 ±8.5 years, 81.7% male) and 4,481 who underwent open AAA repair (mean age: 69.5 ±8.1 years, 75.1% male). Stratifying by quintile, stress test frequency ranged from 13.0% to 68.6% (mean: 37.9%) among EVAR patients and 15.9% to 85.0% (mean: 52.8%) among open AAA repair (Figure). The rate of MACE was 1.4% after EVAR and 10.2% after open AAA repair. MACE after EVAR increased with the frequency of stress testing and was 0.9% at 1 st quintile centers vs 1.7% at 5 th quintile centers (p-trend=0.033). There was no association between MACE and stress testing for open AAA repair (p-trend=0.192). The estimated charges for stress testing prior to EVAR was $125,806 per 1,000 patients at 1 st quintile centers, and $664,975 at 5 th quintile centers, while charges prior to open AAA repair were $153,861 per 1,000 patients at 1 st quintile centers, and $825,473 at 5 th quintile centers. Conclusions: More frequent stress testing is associated with high cost without a reduction in MACE. This lack of return on investment highlights the need for more judicious stress test use prior to AAA surgery.

The additional prognostic value of myocardial perfusion SPECT in patients with known coronary artery disease with high exercise capacity

BackgroundThe prognostic value of myocardial perfusion imaging (MPI) in patients with known coronary artery disease (CAD) and high exercise capacity is still unknown. We sought to determine the MPI additional prognostic value over electrocardiography (ECG) stress testing alone in patients with known CAD who achieved ≥ 10 metabolic equivalents (METs). Methods and ResultsWe evaluated 926 patients with known CAD referred for MPI with exercise stress. Patients were followed for a mean of 32.4 ± 9.7 months for the occurrence of all-cause death or nonfatal myocardial infarction (MI). Those achieving ≥ 10 METs were younger, predominantly male, and had lower prevalence of cardiovascular risk factors. Patients reaching ≥ 10 METs had a lower annualized rate of hard events compared to their counterparts achieving < 10 METs (1.13%/year vs 3.95%/year, P < .001). Patients who achieved ≥ 10 METs with abnormal scans had a higher rate of hard events compared to those with normal scans (3.37%/year vs 0.57%/year, P = .023). Cardiac workload < 10 METs and an abnormal MPI scan were independent predictors of hard events. ConclusionsMPI is able to stratify patients with known CAD achieving ≥ 10 METs for the occurrence of all-cause death and nonfatal MI, with incremental prognostic value over ECG stress test alone.

Impact of Medicare Benefits Schedule (MBS) Item Number Changes on Cardiac Investigations (Plain Echocardiography, Stress Echocardiography, Electrocardiography Stress Testing)

Cardiac investigations are one of the most common investigations conducted in Australia. The Australian Government Department of Health has introduced changes to item numbers in the Medicare Benefits Schedule (MBS) for Plain echocardiography, Stress echocardiography and Electrocardiography Stress Testing, effective from 1 August 2020. The major change is that these investigations cannot be claimed if done in previous 24 months.

ARM EXERCISE ELECTROCARDIOGRAPHIC STRESS TESTING VERSUS REGADENASON MYOCARDIAL PERFUSION IMAGING AND EXERCISE TREADMILL TESTING FOR CLINICAL OUTCOME PREDICTION

Arm exercise electrocardiographic stress testing (ARM) is an alternative to regadenoson myocardial perfusion imaging (RMPI) for patients unable to perform leg exercise but has never been directly compared to RMPI or treadmill exercise (ETT) for clinical outcome prediction. All symptomatic veterans

P4408Cardiovascular response in diabetic patients submitted to treadmill electrocardiographic exercise stress test

Abstract Introduction Diabetes mellitus (DM) is an entity commonly associated with neuropathy, a factor that may have repercussions on the cardiovascular system, specifically in its capacity to respond to stimuli. Objectives To evaluate the cardiovascular response to exercise in diabetic patients, comparing it with a control group. Methods Patients who underwent treadmill eletrocardiographic exercise stress test (EST) between January 2016 and November 2018 without the influence of negative chronotropic medication were included. Results A total of 187 patients were identified, having a mean age of 57±13 years, of whom 120 (64%) were of the male gender. Eighty-four (45%) were diabetic. The group of diabetic patients had a higher prevalence of arterial hypertension, however the number of classes of antihypertensive drugs was not significantly different between diabetic and non-diabetic patients. There were no significant differences in the remaining demographic variables. Patients with DM presented lower maximal heart rates (HR) (141±14 vs 148±19 beats/minute, p=0.015), lower HT reserve (59±16 vs 67±21 beats/minute, p=0.005), as well as a lower rate of HR fall in the recovery period (13±5 vs 16±5 beats/minute2, p&lt;0.001). Total EST time was also lower in diabetic patients (median 7.0 IQR=3 vs 7.3 IQR=3.5 minutes, p=0.044). Additionally, the number of years since the time of diagnosis of DM was inversely correlated with the degree of increase in systolic blood pressure (SBP) with exercise (r=−0.22, p=0.045), and the pre-test SBP (median 135 IQR=24 vs 130 IQR=20 mmHg, p=0.048) and post-test SBP (median 150 IQR=20 vs 140 IQR=25 mmHg, p=0.007) were higher in patients with DM. Discussion In this study it was found that patients with DM present an impaired chronotropic response, both in exercise and recovery periods, and it was observed that the capacity to increase SBP is inversely correlated to the duration of DM. These data may reflect the neuropathic involvement in DM and its influence in the cardiovascular response to exercise.

Early Treadmill ECG Stress Testing After Percutaneous Coronary Intervention Following Hemostasis with the Angioseal™ Vascular Closure Device: A Prospective Single-Center Cohort Study

Objective: Particularly with the transfemoral access, potential complications at the puncture site with early exercise are a major concern. The purpose of this study was to compare femoral artery access site complications after percutaneous coronary interventions (PCI) in 1) patients following a standard care procedure and 2) performing treadmill electrocardiographic (ECG) stress testing within 24 h after application of the Angioseal™ vascular closure device. Methods: This is a prospective, randomised, single-center cohort study conducted in a high-volume tertiary interventional heart centre in Duisburg, Germany. 221 patients were included and 200 entered analysis. Patients were randomly assigned to treadmill testing within 24 h after transfemoral seven French (F) PCI or discharged with the recommendation of limited exercise for two weeks. Clinical examination and Duplex ultrasound (DUS) of the inguinal region was obtained within 24 h after PCI in both groups and repeated immediately after the treadmill test in the exercise group. Two-weeks clinical follow-up was obtained in both groups. Results: Early treadmill testing could be performed without any major limitations or acute complications in all assigned patients. DUS showed no new pseudoaneurysm (PSA) or arteriovenous fistula (AVF) after treadmill testing. At follow-up, there were 1) no differences regarding pain or physical limitations between the two groups and 2) four patients (4%) in the exercise group and seven patients (7%) in the standard care group developed major hematoma (>6 cm)/minor bleeding, which were clinically uneventful. Conclusions: Treadmill ECG stress testing within 24 h of PCI with the femoral access site closed by the Angioseal device was not associated with a higher complication rate compared to standard care.

Preliminary safety analysis of high-intensity interval training (HIIT) in persons with chronic stroke.

The purpose of this study was to assess safety via electrocardiographic (ECG), blood pressure (BP), heart rate (HR), and orthopedic responses to 3 different high-intensity interval training (HIIT) protocols in persons with stroke. Eighteen participants (10 male; 61.9 + 8.3 years of age; 5.8 + 4.2 years poststroke) completed a symptom-limited graded exercise test (GXT) with ECG monitoring to screen for eligibility and determine HR peak. The 3 HIIT protocols involved repeated 30 s bursts of treadmill walking at maximum speed alternated with rest periods of 30 s (P30), 1 min (P60), or 2 min (P120). Sessions were performed in random order and included 5 min warm up, 20 min HIIT, and 5 min cool down. Variables measured included ECG activity, BP, HR, signs and symptoms of cardiovascular intolerance, and orthopedic concerns. Generalized linear mixed models and Tukey-Kramer adjustment were used to compare protocols using p < 0.05. No signs or symptoms of cardiovascular intolerance, significant arrhythmias, ST segment changes, or orthopedic responses resulted in early termination of any HIIT session. HIIT elicited HRs in excess of 88% of measured HRpeak including 6 (P30), 8 (P60), and 2 (P120) participants eliciting a HR response above their GXT HRpeak. Both maximum BP and HR were significantly higher in P30 and P60 relative to P120. Preliminary data indicate that persons with chronic stroke who have been prescreened with an ECG stress test, a symptom-limited GXT, and a harness for fall protection may safely participate in HIIT, generating substantially higher HRs than what is seen in traditional moderate intensity training.

Characterizing artifacts in RR stress test time series.

Electrocardiographic stress test records have a lot of artifacts. In this paper we explore a simple method to characterize the amount of artifacts present in unprocessed RR stress test time series. Four time series classes were defined: Very good lead, Good lead, Low quality lead and Useless lead. 65 ECG, 8 lead, records of stress test series were analyzed. Firstly, RR-time series were annotated by two experts. The automatic methodology is based on dividing the RR-time series in non-overlapping windows. Each window is marked as noisy whenever it exceeds an established standard deviation threshold (SDT). Series are classified according to the percentage of windows that exceeds a given value, based upon the first manual annotation. Different SDT were explored. Results show that SDT close to 20% (as a percentage of the mean) provides the best results. The coincidence between annotators classification is 70.77% whereas, the coincidence between the second annotator and the automatic method providing the best matches is larger than 63%. Leads classified as Very good leads and Good leads could be combined to improve automatic heartbeat labeling.

ST segment/heart rate hysteresis improves the diagnostic accuracy of ECG stress test for coronary artery disease in patients with left ventricular hypertrophy.

The exercise electrocardiographic stress test (ExET) is the most widely used non-invasive diagnostic method to detect coronary artery disease. However, the sole ST depression criteria (ST-max) have poor specificity for coronary artery disease in patients with left ventricular hypertrophy. We hypothesised that ST-segment depression/heart rate hysteresis, depicting the relative behaviour of ST segment depression during the exercise and recovery phase of the test might increase the diagnostic accuracy of ExET for coronary artery disease detection in such patients. In three cardiology centres, we studied 113 consecutive patients (mean age 66 ± 2 years; 88% men) with hypertension-related left ventricular hypertrophy at echocardiography, referred to coronary angiography after an ExET. The following ExET criteria were analysed: ST-max, chronotropic index, heart rate recovery, Duke treadmill score, ST-segment depression/heart rate hysteresis. We detected significant coronary artery disease at coronary angiography in 61 patients (53%). At receiver-operating characteristic analysis, ST-segment depression/heart rate hysteresis had the highest area under the curve value (0.75, P < 0.001 when compared with the 'neutral' receiver-operating characteristic curve value of 0.5). Area under the curve values were 0.68 (P < 0.01) for the chronotropic index, 0.58 (P = NS) for heart rate recovery, 0.57 (P = NS) for ST-max and 0.52 (P = NS) for the Duke treadmill score. Among currently available ExET diagnostic variables, ST-segment depression/heart rate hysteresis offers a substantially better diagnostic accuracy for coronary artery disease than conventional criteria in patients with hypertension-related left ventricular hypertrophy.

Cardiac Computed Tomography Is Cost-Effective Compared With Exercise Stress Testing in Investigating Patients With Stable Chest Pain

Computed Tomography coronary angiography (CTCA) is a non-invasive imaging technique used to detect coronary heart disease(CHD) in patients with stable chest pain of suspected cardiac origin. Exercise electrocardiography stress test (EST) use has previously been the choice of investigation of stable chest pain in Rapid Access Chest Pain Clinics (RACPC). However studies have shown that 30% of people attending RACPC are either unsuitable for EST or achieve non-diagnostic results.1 Randomised control trials have shown cardiac CT of showing more significant disease identification and less inconclusive results when compared to EST.2 This has lead to NICE including cardiac CT in the diagnostic pathway for stable chest pain, and they have called for research on the cost-effectiveness of cardiac CT testing in the diagnosis of angina.

Features of coronary heart disease development in emergency workers of the Chornobyl accident depending on the action of radiation and non-radiation risk factors and genotypes of single nucleotide polymorphism rs966221 of phosphodiesterase 4D gene

This study devoted to specific features of coronary heart disease (CHD) development in emergency work ers (EW) of the accident at the Chernobyl nuclear power plant (ChNPP) based on analysis the interaction between radiation and non radiation risk factors and single nucleotide polymorphism (SNP) rs966221 of phosphodiesterase (PDE) 4D gene. It was examined 397 men with CHD, including 274 EW of 1986-1987 and 123 non irradiated persons (con trol group) who were 66±10 and 69±11 years old relatively. The program studies included clinical examination, elec trocardiography (ECG), ECG daily monitoring, ECG stress testing, echo doppler cardiography, analysis of serum lipid spectrum, polymerase chain reaction with restriction of reaction products, retrospective analysis of case histories. Diagnosis of CHD or its approval was carried out in accordance with the standards of diagnosis, accepted in Ukraine. All EW before their taking part in cleaning ChNPP territory did not suffered from CHD. According to the analysis of contingency tables, carriers of the TT genotype of rs966221 increased the risk of myocardial infarction (MI) in 2.538 times compared with carriers of genotypes CC and CT. The use of Kaplan Meier method showed that a half of EW with the TT genotype developed MI before 64 years old, while with the other geno types up to 78.7 years old. In the control group statistically significant increase of cumulative proportion of patients with MI, carriers of the TT genotype, began from 60 years old. Compared to the non irradiated patients EW fell ill with CHD on 9.4 years earlier. Using proportional hazards analysis (Cox regression), it was found that EW had 3.9 times higher risk of CHD than in non irradiated individuals. Smoking and overweight brought three times less but significant risk - 1.37 and 1.33 respectively. The TT genotype unlike genotypes CC and CT gene PDE4D increased risk of MI in 1.757 times more both in EW and control group. The risk of CHD development was determined by radiation factor, such as the involvement in the emer gency works of the accident consequences, as well as non radiation factors, namely smoking and overweight. Only one factor, the TT genotype of rs966221 PDE4D gene, determined the risk of MI occurrence in EW and non irradiated controls. In the post emergency period, CHD developed 6 years earlier in EW with the TT genotype than in patients with genotypes CC and CT.

Abstract 316: Arm Exercise Heart Rate, Stress Test Findings and Outcome

Attainment of 85% age-predicted peak heart rate (APPHR) during leg exercise is widely accepted and emphasized in clinical textbooks as a condition for adequate diagnostic stress test sensitivity. However, there is little direct evidence for this belief and relationships among peak heart rate, diagnostic sensitivity, coronary revascularization and mortality are poorly characterized. In addition, the prognostic significance of chronotropic incompetence as a predictor of mortality is underappreciated and there is almost no data relating arm exercise heart rate responses to abnormal stress test results and mortality. Thus, the purpose of this study was to investigate relationships among arm exercise heart rate responses, abnormal stress tests findings, coronary revascularization and mortality in patients who could not perform leg exercise. From 1997 to 2002, we conducted arm cycle ergometer stress tests on 446 veterans aged 64±11 years, of whom 253 underwent myocardial perfusion imaging (MPI). We evaluated associations of quartiles of %APPHR and heart rate reserve (%HRR) with an abnormal electrocardiographic (ECG ST depression ≥ 1 mm) or MPI stress test, coronary revascularization and all-cause mortality during follow-up ≥ 10 yrs. An abnormal arm exercise ECG occurred in 62/427 (14.5%) of patients with an interpretable ECG. MPI was abnormal in 157/253 (62.1%). Over 12.0±1.3 yrs. follow-up, there were 256 deaths (57.4%) and 105 patients (23.5%) underwent coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI). An abnormal arm exercise ECG was directly associated with quartile of %APPHR (p = 0.009) and %HRR (p = 0.02) but an abnormal arm exercise MPI exhibited an inverse trend (p = 0.10 and 0.12, respectively). There was a sharp upward inflexion point for increased percent of abnormal arm exercise ECG tests at 69%APPHR. Results for abnormal ECG and MPI tests were similar for patients taking beta blockers. Both %APPHR and %HRR were inversely related to all-cause mortality (p = 0.02 and p = 0.004, respectively) after adjustment for significant demographic and clinical variables. CABG and PCI were each predicted by an abnormal arm exercise ECG (p &lt; 0.04) and PCI alone by abnormal MPI (p= 0.02) with no interaction of %APPHR or %HRR. We conclude that higher %APPHR and %HRR are associated with greater likelihood of an abnormal arm exercise ECG, particularly above 69%APPHR, but borderline reduced likelihood of abnormal arm exercise MPI in patients unable to perform leg exercise. An abnormal arm exercise ECG predicts CABG and PCI and MPI predicts PCI with no apparent influence of %APPHR or %HRR. Higher arm exercise %APPHR and %HRR are related to lower all-cause mortality.

Coronary Angiographic Significance of Hyperacute St-T Changes Associated with Regadenoson Stress

An abnormal electrocardiographic stress test is typically characterized by ST segment depression. In rare cases, ST segment elevation is observed, which, in the absence of diagnostic Q waves, has anatomic specificity for localized myocardial ischemia. Most instances of ST elevation occurring during cardiac stress testing have been observed with exercise, with only six cases reported with pharmacologic stress. Despite different physiologic mechanisms for inducing myocardial ischemia, development of ST segment elevation during pharmacologic stress, as illustrated by the present case, may also be indicative of critical coronary stenoses, warranting urgent coronary arteriography.

Value of Exercise Tolerance Testing In Evaluation of Diabetic Patients Presented With Atypical Chest Discomfort

BackgroundCoronary artery disease is the single most important cause of mortality and morbidity in diabetic patients. Electrocardiographic stress test is a non-invasive modality to screen significant coronary involvement in minimally symptomatic diabetics.ObjectivesWe investigated the Positive Predictive Value (PPV) of this test in comparison with coronary angiography.Materials and Methods130 diabetic patients with atypical chest discomfort were studied and tested using Exercise Tolerance Test (ETT) among which 100 cases showed positive results that further were studied invasively by selective coronary angiography.ResultsThe positive predictive value of ETT for diagnosis of Coronary Artery Disease (CAD)among diabetic patients presented with atypical chest discomfort was 77%.ConclusionWe conclude that electrocardiographic stress test is a valuable inexpensive non-invasive screening test in diabetic patients with atypical chest discomfort.

Guidelines on Diagnosis and Treatment of Stable Ischemic Heart Disease: Keeping Up With a Constantly Evolving Evidence Base

This issue includes guidelines from the American College of Physicians on the diagnosis and management of patients with SIHD. The editorialist discusses the complexity of the recommendations, how c...

Myocardial perfusion imaging and risk classification for coronary heart disease in diabetic patients. The IDIS study: a prospective, multicentre trial

To determine whether stress-rest myocardial perfusion single-photon emission (MPS) computed tomography improves coronary heart disease (CHD) risk classification in diabetic patients. In 822 consecutive diabetic patients, risk estimates for a CHD event were categorized as 0% to <3%, 3% to <5%, and ≥5% per year using Cox proportional hazards models. Model 1 used traditional CHD risk factors and electrocardiography (ECG) stress test data and model 2 used these variables plus MPS imaging data. We calculated the net reclassification improvement (NRI) and compared the distribution of risk using model 2 vs. model 1. CHD death, myocardial infarction and unstable angina requiring coronary revascularization were the outcome measures. During follow-up (58 ± 11 months), 148 events occurred. Model 2 improved risk prediction compared to model 1 (NRI 0.25, 95% confidence interval, CI, 0.15-0.34; p < 0.001). Overall, 301 patients were reclassified to a higher risk category, with an event rate of 28%, and 26 to a lower risk category, with an event rate of 15%. Among patients at 3% to <5% risk, 53% were reclassified at higher risk and 25% at lower risk (NRI 0.42, 95% CI 0.07-0.76; p < 0.05). The cost per NRI was $880.80 for MPS imaging as compared to an outpatient visit with an ECG stress test. The addition of MPS imaging data to a prediction model based on traditional risk factors and ECG stress test data significantly improved CHD risk classification in patients with diabetes.