Predictor Of Myocardial Ischemia Research Articles

Angiography-derived radial wall strain as a predictor of myocardial ischemia, high-risk plaque, and outcomes

Abstract Background Angiography-derived radial wall strain (RWS) is a novel method to assess the biomechanical characteristics of the underlying plaque. There is limited data regarding how the biomechanical attributes of atherosclerotic lesions relate to their physiologic and morphological attributes. Purpose This study aimed to investigate the association of RWS with myocardial ischemia and high-risk plaque, and their prognostic implication. Methods From the international CCTA-FFR registry, 484 deferred vessels underwent RWS analysis. Angiography-derived RWS was defined as relative changes of lumen diameter within the cardiac cycle, expressed as a percentage of the largest lumen diameter. Plaque characteristics were assessed in a coronary CT angiography core laboratory and high-risk plaque was defined as 3 or more high-risk plaque characteristics (HRPC) including minimum lumen area <4.0 mm2, plaque burden ≥70%, low-attenuation plaque, and positive remodeling. Functional significance of coronary lesion was assessed by invasively measured fractional flow reserve (FFR). The primary outcome was vessel-oriented composite outcome (VOCO), a composite of cardiac death, target vessel myocardial infarction, or target vessel revascularization at 5 years. All clinical outcomes were adjudicated by an independent clinical event committee. Results The mean FFR was 0.89±0.07, and that for maximum RWS (RWSmax) was 11.2±2.5%. RWS proportionally increased along with the decrease in FFR values, and the increase in the number of HRPC (Both p-for-trend <0.001). The proportion of vessels with FFR ≤0.80 and that of vessels with high-risk plaque increased in the order of RWSmax quartile group (Both p-for-trend <0.001) and these associations maintained after the adjustment of clinical characteristics (adjusted odds ratio [OR] 1.31, p value <0.001 for FFR ≤0.80; adjusted OR 1.24, p value <0.001 for high-risk plaque) and angiographic parameters (adjusted OR 1.24, p value <0.001 for FFR ≤0.80; adjusted OR 1.14, p value 0.012 for high-risk plaque). High RWSmax (>14.2%, optimal cut-off value for VOCO) was an independent predictor for VOCO after adjusting for diabetes and % diameter stenosis, FFR ≤0.8, or high-risk plaque (Figure 1). In a mediation analysis, RWS showed an independent effect from lesion-specific ischemia or high-risk morphological attributes in defining prognosis (Figure 2). Conclusion(s) Angiography-derived RWS was closely related to coronary physiologic and plaque morphological attributes, but was an independent predictor of clinical events. This novel index can provide additional prognostic implications over physiological severity or plaque characteristics in patients with coronary artery disease.Prognostic implications of high RWSMediation analysis

Predictors of Myocardial Ischemia in Patients with Kawasaki Disease: Insights from Patient-Specific Simulations of Coronary Hemodynamics.

Current treatments for patients with coronary aneurysms caused by Kawasaki disease (KD) are based primarily on aneurysm size. This ignores hemodynamic factors influencing myocardial ischemic risk. We performed patient-specific computational hemodynamics simulations for 15 KD patients, with parameters tuned to patients' arterial pressure and cardiac function. Ischemic risk was evaluated in 153 coronary arteries from simulated fractional flow reserve (FFR), wall shear stress, and residence time. FFR correlated weakly with aneurysm [Formula: see text]-scores (correlation coefficient, [Formula: see text]) but correlated better with the ratio of maximum-to-minimum aneurysmal lumen diameter ([Formula: see text]). FFR dropped more rapidly distal to aneurysms, and this correlated more with the lumen diameter ratio ([Formula: see text]) than [Formula: see text]-score ([Formula: see text]). Wall shear stress correlated better with the diameter ratio ([Formula: see text]), while residence time correlated more with [Formula: see text]-score ([Formula: see text]). Overall, the maximum-to-minimum diameter ratio predicted ischemic risk better than [Formula: see text]-score. Although FFR immediately distal to aneurysms was nonsignificant, its rapid rate of decrease suggests elevated risk.

Plasma hydroxyanthranilic acid as a predictor of stress induced myocardial ischemia in non-obstructive coronary artery disease

Abstract Background The tryptophan catabolite hydroxyanthranilic acid (HAA) has potent immunomodulatory and vasoactive effects. HAA is also a precursor in the synthesis of nicotinamide adenine dinucleotide (NAD), a crucial cofactor in energy-metabolism. We have previously demonstrated that elevated plasma HAA predicted risk of myocardial infarction. Purpose To explore if plasma HAA is associated with stress induced myocardial ischemia in non-obstructive coronary artery disease (CAD). Methods In 132 patients with chest pain and non-obstructive CAD by coronary computed tomography angiography (CCTA), plasma HAA was analyzed by gas chromatography tandem mass spectrometry. All participants underwent myocardial contrast stress echocardiography. Myocardial ischemia was assessed as delayed contrast replenishment at peak dobutamine stress during real-time low mechanical index imaging and destruction replenishment. The extent of ischemia was defined as the number of segments with delayed contrast enhancement using a 17-segment left ventricular model. Associations of plasma HAA with myocardial ischemia was evaluated in a multivariate adjusted linear regression model. Results Mean (SD) age at inclusion was 63 (8) years and 56% were women. At CCTA, the median (25th, 75th percentile) coronary artery calcium (CAC) score was 42 (13–107) Agatston units, whereas the mean (SD) segment involvement score (SIS) was 2.6 (1.6). Myocardial ischemia was found in 52% of patients with on average 5 (3) ischemic segments per patient. Serum HAA did not correlate with the CAC score or SIS (p>0.29). After multivariate adjustment including age, sex, body mass index, systolic blood pressure, diabetes, current smoking, and LDL cholesterol, the odds ratio and 95% confidence interval for myocardial ischemia was 1.55 (1.04–2.32), P=0.03, per SD increment of plasma HAA levels (log transformed). Plasma HAA was also associated with the extent of myocardial ischemia with a multivariate adjusted β of 0.26, P=0.004. Conclusion Plasma HAA is associated with the extent of myocardial ischemia in non-obstructive CAD. Potential roles of this metabolite in atherogenesis, vascular dysfunction and as a predictor of myocardial ischemia should be further elucidated. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): Western Norway Regional Health Authority

Clinical Significance of Ventricular Premature Contraction Provoked by the Treadmill Test.

Background and Objectives: The treadmill test (TMT) is a predictive tool for myocardial ischemia. Recently, exercise-provoked ventricular premature contracture (VPC) during TMT was shown to have a relation with coronary artery disease and cardiovascular mortality. Therefore, we evaluate clinical correlates of exercise-provoked VPC and compare the predictive power for myocardial ischemia and cardiovascular events. Method: Data of 408 patients (≥18 years of age) who underwent TMT for work up of angina, palpitation, dyspnea, syncope, or arrhythmia between February 2015, and January 2016, were collected with consent at Samsung Medical Center, Seoul, Republic of Korea. Among total of 408 patients, 208 were excluded according to the previous history of PCI or CABG, previous MI, decreased left ventricular ejection fraction lower than 50%, arrhythmia that could affect ST-segment change on ECG. Results: Among 200 patients, 32 (16.0%) developed exercise-provoked VPC (21 patients in the exercise phase, 20 patients in the recovery phase). Of them, 20 patients (10.0%) showed positive TMT, and 4 patients (2.0%) underwent revascularization after TMT. Among 21 patients showing exercise phase VPC, 5 (23.8%) showed positive TMT results. In patients younger than 65 years, exercise phase VPC was associated with positive TMT (odds ratio 6.879, 1.458–32.453) considering demographics and previous medical history in multivariable analysis. Among the 20 patients showing recovery phase VPC, 2 (10.0%) underwent revascularization after TMT. In multivariable analysis, recovery phase VPC was associated with revascularization (odds ratio 9.381, 1.144–76.948) considering age, sex, BMI, and TMT result. Conclusion: VPC during the treadmill test was a useful predictor of myocardial ischemia in this study.

Relationship Between Serum Concentration of Adrenomedullin and Myocardial Ischemic T Wave Changes in Patients With Lung Cancer.

BackgroundPatients with lung cancer are at increased risk for the development of cardiovascular diseases. Molecular markers for early diagnosis of cardiac ischemia are of great significance for the early prevention of cardiovascular events in patients with lung cancer. By evaluating the relationship between adrenomedullin (ADM) and myocardial ischemic T wave changes, the clinical value of circulating ADM as a predictor of myocardial ischemia in patients with lung cancer is confirmed.MethodsWe enrolled patients with lung cancer and healthy people from 2019 to 2021 and extracted a detailed ECG parameter. After adjustment for potential confounders, logistic regression was used to assess the association of clinical data. We performed analyses on differences in T wave between patients with lung cancer and healthy people, and the relationship between T wave and ADM among patients with lung cancer. Receiver operator characteristic (ROC) curves were drawn to confirm the diagnostic value of biomarkers.ResultsAfter adjusting for potential confounders, the incidence of T wave inversion or flattening in patients with lung cancer was higher than in healthy people (OR: 3.3228, P = 0.02). Also, further analysis of the data of lung cancer patients revealed that the ADM in lung cancer patients with T wave inversion or flat was higher than those with normal T wave (189.8 ± 51.9 vs. 131.9 ± 38.4, p < 0.001). The area under the ROC curve was 0.8137.ConclusionAmong the patients with lung cancer, serum ADM concentration is associated with the incidence of the abnormal T wave. ADM might be a potentially valuable predictor for heart ischemia in patients with lung cancer.

Clinical values of resting electrocardiography in patients with known or suspected chronic coronary artery disease: a stress perfusion cardiac MRI study

BackgroundElectrocardiography (ECG) is an essential investigation in patients with chronic coronary artery disease (CAD). However, evidence regarding the diagnostic and prognostic value of ECG in this population is limited. Therefore, we sought to determine whether baseline ECG abnormalities were associated with myocardial ischemia and cardiac events in patients with known or suspected chronic CAD.MethodsConsecutive patients with known (n = 146) or suspected chronic CAD (n = 349) referred for adenosine stress cardiac magnetic resonance (CMR) between 2011 and 2014 were enrolled. Resting ECGs were classified as major, minor, and no abnormalities. Predictors of myocardial ischemia on CMR and major adverse cardiac events (MACE) including cardiac death, nonfatal myocardial infarction, hospitalization for heart failure and late revascularization (> 180 days after CMR) were evaluated.ResultsAverage age was 69 ± 11 years (51% men). One hundred and eighty-five patients (37.4%) had major and 154 (31.1%) had minor ECG abnormalities. In patients with suspected CAD, myocardial ischemia was presented in 83 patients (23.8%). Multivariable analysis demonstrated major ECG abnormality as the strongest predictor of myocardial ischemia (HR 2.51; 95% CI 1.44–4.36; p = 0.001). Adding ECG to clinical pretest probability models improved the prediction of myocardial ischemia in ROC analyses (p = 0.04). In the whole cohort (n = 495), 91 MACE occurred during the median follow-up period of 4.8 years. Multivariable analysis showed that diabetes mellites, history of heart failure, prior revascularization, left ventricular ejection fraction, ischemia, and major ECG abnormality were independent predictors of MACE.ConclusionAbnormal resting ECG is common in patients with known or suspected chronic CAD. ECG had important diagnostic and prognostic values in this population.

Patterns of [18F]FDG myocardial uptake in oncology patients as a predictor of myocardial ischaemia on stress myocardial perfusion imaging.

There is variable cardiac uptake observed on oncological ¹⁸F-fludeoxyglucose ([¹⁸F]FDG) positron emission/computed tomography (PET/CT). The main purpose of this study is to evaluate patterns of overnight fasting myocardial [¹⁸F]FDG uptake in oncological PET/CT and analyse the relationship between myocardial [¹⁸F]FDG uptake and myocardial ischaemia on stress single-photon emission CT (SPECT) myocardial perfusion imaging (MPI). A total of 362 subjects underwent both oncological PET/CT and stress SPECT MPI within 3 months of each other. Subjects with focal-mass-like [¹⁸F]FDG myocardial uptake raising the suspicion of cardiac metastasis and subjects with coronary artery disease (CAD) were excluded. The myocardial [18F]FDG uptake was classified into four patterns. Abnormal SPECT MPI was noted in 91 (25%) patients; 220 (61%) patients had completely absent [18F]FDG uptake, 80 (22%) had diffuse [¹⁸F]FDG uptake, 39 (11%) had focal on diffuse [¹⁸F]FDG uptake, and 23 (6%) had focal or regional myocardial [¹⁸F]FDG uptake, the regional [¹⁸F]FDG myocardial uptake was the most predictive of myocardial ischaemia on SPECT MPI, and there were positive associations between age, sex, hypertension, tobacco smoking, hypercholesterolemia, and left ventricular ejection, a fair agreement was noted between the focal or regional FDG uptake and presence of ischaemia on SPECT, K = 0.394 (95% CI 0.164 to 0.189). Based on the presented findings, the physiological myocardial [¹⁸F]FDG uptake in fasting oncology patients is variable. The regional myocardial [¹⁸F]FDG uptake pattern is the most frequent pattern associated with myocardial ischaemia on stress SPECT MPI, however, the agreement between regional FDG uptake and presence of ischaemia on SPECT is fair.

Predictors of Myocardial Ischemia in Preoperative Oncology Patients Who Underwent Fluorodeoxyglucose-Positron Emission Tomography Study.

Background:Coronary artery calcification (CAC) can be visually estimated on computed tomography (CT) attenuation correction (CTAC) of positron emission tomography (PET). The visual estimation of CAC from CTAC scans performed for PET/CT is comparable to the standard CAC score scan. Myocardial perfusion imaging (MPI) with single-photon emission CT (SPECT) is commonly performed for risk stratification before oncologic surgery.Objective:We investigated the value of visual estimation of CAC from CTAC of PET/CT as well as other factors such as coronary artery disease (CAD) risk factors and type of cancer as predictors of MPI ischemia.Methods:Retrospectively, we identified 268 patients who underwent PET/CT and MPI for preoperative cardiac evaluation. Visual estimation of CAC was performed and classified into four categories.Results:The results of visual CAC were as follows: 47.8% – zero CAC, 32.8% – mild CAC, 14.2% – moderate CAC, and 5.2% – severe CAC. The majority of patients (85.8%) had normal MPI, whereas 14.2% were abnormal. There was a strong association between ischemia on MPI and CAC seen on CTAC (P < 0.01), dyslipidemia (P < 0.01), family history of CAD (P < 0.05), smoking (P < 0.01), and type of malignancy (P < 0.01).Conclusion:A strong association exists between visual estimation of CAC on CTAC and MPI. Zero is highly associated with normal MPI, but moderate-to-severe CAC is associated with abnormal MPI, in addition smoking, dyslipidemia, and certain cancer are associated with ischemic MPI; subsequently, preoperative cardiac testing is warranted in these subsets of patients.

A study on umbilical cord blood cardiac troponin T as an early predictor of myocardial ischaemia in perinatal asphyxiated newborns

Objectives: To predict the occurrence of myocardial ischaemia in the first 72 hours of life in perinatal asphyxiated newborns by estimating cord blood cardiac troponin T. Method: Fifty newborns with Apgar scores ≤ 6 at 5 minutes of birth from October 2012 to October 2014 were included in the study. Cord blood samples of those babies were taken for estimation of cardiac troponin T (cTnT) by the Immunoassay Elecsys Troponin T STAT (Roche) method. Umbilical cord blood cTnT level above 0.097ng/ml was considered as positive. Further, those newborns were managed in the neonatal intensive care unit (NICU) according to severity and monitored for hypotension with requirement of inotropes. In the next 72 hours those who required inotropes were screened for myocardial ischaemia by electrocardiogram (ECG) and echocardiogram (ECHO). Results: Out of the 50 cases, 45 developed myocardial ischaemia and cord blood was positive for cTnT in 40 cases which was statistically very significant ( p = 0.0001). Further, when comparison was done between Group A (moderate asphyxia) and Group B (severe asphyxia), there was no statistical significance (p = 0.57). Conclusions: Irrespective of the severity of perinatal asphyxia, cord blood cTnT >0.09ng/ml will help to predict occurrence of myocardial ischaemia in the first 72 hours of life in perinatal asphyxiated newborns. Sri Lanka Journal of Child Health, 2019 ; 48 (2): 152- 154

Prevalence and predictors of myocardial ischemia by preoperative myocardial perfusion single photon emission computed tomography in patients undergoing noncardiac surgery.

BACKGROUNDThe prevalence and predictors of myocardial ischemia before noncardiac surgery are unknown. In addition the predictive value of myocardial perfusion single-photon emission computed tomography (SPECT) before noncardiac in individual patients is uncertain.OBJECTIVEEvaluate the prevalence and predictors of myocardial ischemia before noncardiac surgery, and determine the postoperative cardiac outcome based on results of myocardial perfusion SPECT.DESIGNRetrospective.SETTINGSingle tertiary care center.PATIENTS AND METHODSWe reviewed the records of adult patients diagnosed with myocardial ischemia by myocardial perfusion SPECT who were undergoing noncardiac surgery. Myocardial perfusion SPECT had been performed within 4 weeks prior to noncardiac surgery requiring general anesthesia.MAIN OUTCOME MEASURESPrevalence of abnormal myocardial perfusion SPECT results on preoperative evaluation; abnormal myocardial perfusion SPECT results as a predictor for postoperative cardiac events such as cardiac death, nonfatal myocardial infarction, and unstable angina.RESULTSOf 131 patients who underwent noncardiac surgery from February 2015 to April 2016, 84 (64%) patients were female and the mean (SD) age was 64.1 (13.6) years. The prevalence of abnormal myocardial perfusion SPECT was 18% (24 of 131). Normal myocardial perfusion SPECT was highly predictive (up to 100%), but a positive myocardial perfusion SPECT had low positive predictive value (4%). Variables associated with an abnormal myocardial perfusion SPECT included ischemic heart disease, congestive heart failure, ASA score of 3 or more, limited exercise capacity (less than 4 METs), male sex, hypercholesterolemia, hypertension, smoking, and abnormal ECG. In a multivariable analysis, history of ischemic heart disease and history of smoking were significant predictors of abnormal myocardial perfusion SPECT (P=.001, and .029, respectively).CONCLUSIONSBecause of the low positive predictive value of myocardial perfusion SPECT, utilization of the technique in the workup of cardiac patients undergoing noncardiac surgery has been inappropriate. Myocardial perfusion SPECT should be restricted to only clearly defined appropriate use criteria.LIMITATIONSRelatively small number of patients and retrospective design.

Abstract 9916: Evaluation of the Best Cut-off Value of Ischemia in Instantaneous Wave-Free Ratio in Patients With Aortic Valve Stenosis

Background: Instantaneous wave-free ratio (iFR) is a vasodilator free index calculated using trans-lesional pressure ratio during a specific period of diastole that is called “wave-free period”, and reported to have a good correlation with fractional flow reserve (FFR). In patients with severe aortic valve stenosis (AS), evaluation of intermediate coronary stenosis by FFR using vasodilators is thought to be a contraindication in some situations. Moreover, previous studies reported unique coronary flow pattern during diastolic phase in patients with AS. To date, there is no report claiming the correlation of iFR and FFR in this population. The purpose of the present study was to examine the clinical value of iFR in patients with AS. Method and Results: We examined consecutive 154 patients (with 214 stenosis) whose iFR and FFR were measured simultaneously. The mean age of AS patients (n=10, mean aortic valve area: 0.75 ± 0.42cm2) was higher than non-AS patients (n=144). Other patients’ characteristics are shown in Table 1. The mean iFR value in AS patients was significantly lower than that of non-AS patients, despite no significant difference was observed in the mean FFR value and % diameter stenosis (Table 2). iFR showed a good correlation with FFR in AS patients (Figure 1) and the best cut-off value of iFR in receiver operator curve analysis to predict FFR ≤ 0.8 was 0.73 in AS patients (AUC 0.84, sensitivity 0.8, specificity 0.86, p=0.016; Figure 2), whereas, 0.90 in non-AS patients. Conclusion: The present study demonstrated the good correlation between iFR and FFR in AS patients. Besides, the value below 0.73 of iFR was thought to be a predictor of myocardial ischemia in AS patients, which was lower than standard predictive range of ischemia in iFR. Vasodilator-free assessment by iFR may have potential benefits in evaluating intermediate coronary stenosis in patients with AS.

0334: Coronary artery calcium score as a predictor of myocardial ischemia in asymptomatic diabetic patients

High coronary artery calcium (CAC) scores were shown to predict a higher likelihood of inducible myocardial ischemia and to be associated with a poor cardio-vascular prognosis. However the predictive value for coronary stenoses (CS) has not been tested in asymptomatic diabetic patients. This study aimed to evaluate the predictive value of a high CAC score for silent myocardial ischemia (SMI) and CS in high risk asymptomatic diabetic patients. CAC score was measured by computed tomography in 150 diabetic patients without cardiac history or symptom, with a normal resting ECG and ≥1 additional risk factors. SMI was assessed using stress myocardial scintigraphy and/or stress echocardiography, and CS using coronary angiography in those with an abnormal SMI test. CAC score was ≥100 Agatston units in 35.3% of the patients. SMI was detected in 27 patients (18.0%). A coronary angiography was performed in 17 of SMI patients and detected significant CS in six of them. CAC score was associated with coronary status (no SMI: median value 14 (range 0-2900); SMI without CS: 101 (23-3230) and SMI with CS: 800 (76-2978); (p<0.01)), and similarly for a CAC score ≥100 (in 37/123 patients without SMI (30.2%), 6/11 with SMI and no CS (54.5%) and 5/6 patients with SMI and CS (83.3%) (p<0.05). A CAC score ≥100 predicted the presence of SMI: 30.2% of patients had SMI vs 11.3% of those with CAC <100 (odds ratio 3.4 [1.4-8.0], p<0.01), with a sensitivity and specificity of 59% and 70%, and positive and negative predictive values of 30 and 87%, respectively. These data suggest that in asymptomatic high risk diabetic patients CAC score is associated with cardiac ischemic status, with a 3.4-fold increased risk of SMI when the score is ≥100. The negative predictive value of CAC score for SMI is an interesting finding. The predictive value for CS remains to be determined in a larger sample of patients with CS.

Metabolic Syndrome is the Main Predictor of Myocardial Ischemia in SPECT

Background: Data show that metabolic syndrome (MS) increases the risk of cardiovascular disease. Objectives: To describe and compare the scintigraphic abnormalities and the predictive value of myocardial ischemia in individuals with and without MS referred for single photon emission computed tomography (SPECT) in a University Hospital using three diagnostic criteria. Methods: Prospective observational study of patients referred for SPECT from June to December 2010. Height, weight and waist circumference were measured. Risk factors were assessed and medical records were reviewed to look for parameters for laboratory diagnosis of MS and complete SPECT reports. Results: The study included 203 patients; 138 women (68.0%); mean age 63.6±11.5 years. Metabolic syndrome was found in 135 patients (66.5%). Of the 99 abnormal tests, 91.9% (n=91) occurred in patients with MS and 8.1% (n=8) in patients without MS. There was a significant association between MS and abnormal scintigraphy (67.0% vs. 11.8%; p<0.001) and patients with MS had abnormalities of greater extent and severity (summed stress score (SSS)=7.3±6.5 vs. 3.0±0.9; p<0.001 and summed difference score (SDS)=3.4±4.3 vs. 0.9±2.5; p<0.001). MS was an independent predictor of myocardial ischemia in the three definitions studied (OR=10.07, 6.25 and 4.26 for modified NCEP-ATP III, NCEP-ATP III and IDF, respectively). Conclusions: Patients with MS had more perfusion defects on SPECT (both fixed and reversible); and MS defined by the modified NCEP-ATP III was the best independent predictor of myocardial ischemia on scintigraphy.

Coronary artery plaque burden is a predictor of myocardial ischemia in non-ST elevation myocardial infarction in both genders

Purpose: Women with non-ST elevation myocardial infarction (NSTEMI) have less obstructive coronary artery disease, but the same extent of myocardial ischemia. This may be explained by larger coronary artery plaque burden and tortuosity. The impact of these factors on myocardial ischemia is not entirely known in NSTEMI patients. Methods: In 108 patients (age 67±12 years, 32% women) hospitalized with NSTEMI, coronary artery plaque burden and tortuosity (≥3 curves >45°) was assessed by quantitative coronary angiography. Significant coronary artery stenosis was defined as lumen diameter reduction of ≥ 50%. The extent of myocardial ischemia was assessed by myocardial contrast echocardiography using a 17 segment left ventricular (LV) model. Results: Women with NSTEMI had the same total coronary artery plaque burden as men (35.1±21.8 vs. 43.2±21.3mm2, p=ns) and the same extent of myocardial ischemia (6.9±3.7 vs. 7.2±3.7 LV segments, p=ns). More women had non-significant coronary artery stenoses (27 vs. 10%, p<0.05) and tortuous coronary arteries (82% vs. 61%, p<0.05). There were no significant differences in age (70±12 vs. 66±12 years), prevalence of hypertension (44% vs. 43%) or diabetes (21% vs. 19%) between genders (all ns). Coronary artery plaque burden, significant coronary artery stenosis and age all predicted larger extent of myocardial ischemia independent of gender, tortuosity, diabetes and hypertension in multiple linear regression analysis (Multiple R2= 0.25, all p<0.01) (Table). View this table: Table 1. Predictors of extent of myocardial ischemia in NSTEMI Conclusions: Total coronary artery plaque burden is an independent predictor of myocardial ischemia in NSTEMI patients. The mismatch between coronary artery stenosis and myocardial ischemia previously found in women with NSTEMI cannot be explained by differences in coronary artery tortuosity or plaque burden.

Coronary artery plaques and myocardial ischaemia

To prospectively examine coronary artery plaques as predictors of myocardial ischaemia using cardiac magnetic resonance (CMR). Fifty-two patients (46 men; age 64 ± 10) with suspected coronary artery disease (CAD) referred for catheter coronary angiography (CA) underwent CMR and computed tomography coronary angiography (CTCA). All coronary segments were evaluated for morphological stenosis based on CA. Any plaque according to its composition was assessed based on CTCA. Numbers of total and calcified coronary artery plaques represented the best predictors of myocardial ischaemia (AUC = 0.87; [95%CI: 0.77-0.97] and AUC = 0.87; [95%CI: 0.77-0.96], respectively, p = 0.56) with the total plaque number significantly higher in patients with corresponding ischaemia than those without (p < 0.01, p < 0.05 adjusted for pre-test probability and stenosis). Compared with the AUC of coronary stenosis assessment by CA (AUC = 0.90; [95%CI: 0.80-1.00]), AUCs were equivalent using either the total number or the number of calcified plaques alone (p = 0.73 and p = 0.69). Multivariate logistic regression analyses demonstrated the total plaque number as an independent predictor of ischaemia (odds +20%; [95%CI: 1.096-1.368]), improving a model including clinical probability estimates of CAD (c-statistics, 0.66 to 0.89). Coronary artery plaque number according to CTCA is a significant, independent predictor of myocardial ischaemia with similar accuracy to stenosis assessment.

Usefulness of P-Wave Duration to Identify Myocardial Ischemia During Exercise Testing

It is well recognized that ST-segment depression is due to subendocardial ischemia secondary to an increase in left ventricular end-diastolic pressure. The increase in left ventricular end-diastolic pressure is associated with increased left atrial pressure, resulting in left atrial wall distension that contributes to increasing P-wave duration (PWD). The objective of this study was to determine if PWD measured in leads II and V(5) during maximum exercise stress testing could be a reliable predictor of myocardial ischemia. Patients with suspected coronary disease underwent maximum exercise stress testing with myocardial perfusion imaging. PWD was measured using leads II and V(5) at rest and after exercise, with electrocardiographic complexes magnified 4 times (100 mm/s, 40 mm/mV). The change in PWD was calculated as Delta = PWD(recovery) - PWD(rest). DeltaPWD and ST-segment changes were related to the absence or presence of ischemia (localized reversible perfusion abnormalities) on myocardial perfusion imaging scans. DeltaPWD had sensitivity of 72%, specificity of 82%, negative predictive power (NPP) of 90%, and positive predictive power of 57%. ST-segment change had sensitivity of 34%, specificity of 87%, NPP of 80%, and positive predictive power of 47%. When DeltaPWD and ST changes were combined, sensitivity increased to 79% and NPP increased to 91%. In conclusion, DeltaPWD outperformed ST-segment changes in predicting myocardial ischemia on myocardial perfusion imaging scans. Furthermore, when DeltaPWD and ST-segment changes were combined, sensitivity and NPP were also significantly increased. In this study population, measuring DeltaPWD substantially increased the diagnostic value of maximum exercise stress testing.

Is continuous T-wave monitoring a more sensitive predictor of myocardial ischaemia than continuous ST-segment monitoring in patients with unstable angina pectoris?

Is continuous T-wave monitoring a more sensitive predictor of myocardial ischaemia than continuous ST-segment monitoring in patients with unstable angina pectoris?

Is continuous T-wave monitoring a more sensitive predictor of myocardial ischaemia than continuous ST-segment monitoring in patients with unstable angina pectoris?

Is continuous T-wave monitoring a more sensitive predictor of myocardial ischaemia than continuous ST-segment monitoring in patients with unstable angina pectoris?

Dynamic changes of QT dispersion as a predictor of myocardial ischemia on exercise testing in patients with angina pectoris.

The difference between the maximum and minimum QT intervals on the standard 12-lead ECG (QT dispersion) may be a significant predictor of serious arrhythmias. Dynamic changes in QTd were determined during exercise-induced ischemia in 15 patients with effort angina (> or = 75% coronary stenosis) and 10 normal individuals. Treadmill exercise testing was performed according to Bruce's protocol and the rate-corrected QT dispersion (QTcd) was calculated using Bazett's formula. The resting QTcd before exercise was similar in the angina patients and the controls. After the first stage of exercise, QTcd was significantly increased in the angina patients (p = 0.035), while it remained near baseline in the controls. Five minutes after completing exercise, QTcd was significantly greater in the angina patients than in the controls (p = 0.011). Furthermore, QTcd values after the first stage of exercise were significantly correlated with the maximum ST depression observed on completing exercise in the angina patients (r = 0.714, p = 0.0028). Because QTd may represent the heterogeneity of ventricular repolarization, its significant exercise-induced increase in the angina patients suggests that myocardial ischemia caused repolarization disorders. The significant correlation between QTcd values after the first stage of exercise (before significant ST depression) and the maximum ST depression on completing exercise suggests that an increase in QTcd preceding ischemic ST depression may predict myocardial ischemia. In addition, even daily activities not causing significant ST changes may increase QTcd and the risk of serious arrhythmia in angina patients.

ST-segment depression during adenosine infusion as a predictor of myocardial ischemia

The incidence and hemodynamic changes associated with ST-segment depression during adenosine stress testing are poorly defined. To examine this, 550 consecutive patients who underwent adenosine perfusion testing were evaluated for the development of ST-segment depression. At least 1 mm of horizontal or downsloping depression developed in 82 patients (15.9%) and was observed with similar frequency in patients with normal scans and those with only fixed defects. ST depression developed in 58 of 242 patients with reversible defects (sensitivity = 24%) and in only 24 of 275 patients without reversible defects (specificity = 91%). Its presence was highly predictive of reversible perfusion defects (predictive accuracy = 71%). Similar findings were observed in patients with and without ECG evidence of left ventricular hypertrophy. Patients with ST depression had perfusion defects in more vessel distributions, had more severe defects, and had a greater increase in heart rate during adenosine infusion. Thus ST-segment depression occurs infrequently during adenosine infusion but is specific for and predictive of myocardial ischemia, as evidenced by reversible perfusion scan defects. Patients with ST depression have more severe disease and develop faster heart rates during infusion, which could result in decreased coronary perfusion during diastole allowing for the development of myocardial ischemia.