Silent Myocardial Ischemia Group Research Articles

Анализ функций миокарда по данным Стресс-эхокардиографии при безболевой ишемии миокарда

The purpose — to analyze the results of stress-EchoCG in patients with and without silent myocardial ischemia (SMI). Material and methods. Results of stress-EchoCG of 202 patients during exercise test (ET) on treadmill according to Bruce protocol were analyzed. Results. Patients with SMI were 2.5 times more likely to achieve submaximal heart rate (p = 0.015) compared with the control group (CG). With the same exercise load, the maximum heart rate was higher in SMI group (p = 0.04). Maximum depression of ST segment was greater in SMI than in CG (p = 0.04). Dynamic of ST segment during ET was found in 75.6% subjects in SMI group and in 36.6% subjects in CG (p = 0.0001). Decrease in myocardial contractility during ET was 80.5% in SMI and 34.1% in CG (p = 0.0001). Combination of ST segment depression and contractility decrease was 56% in SMI and 9.2% in CG (p = 0.0001). In SMI, contractility decrease was found in 84.2% of segments. Conclusions. Decrease in contractility is higher in SMI than in CG. Positive ET with ST segment depression is more common in SMI. Depression of ST segment on positive ET was deeper in SMI than in CG. Negative test happens more often at SMI. Duration of ET in SMI was shorter due to rapid achievement of submaximal heart rate or ST segment depression. In SMI, ischemic manifestations occurred earlier and were more severe than in CG. Combination of segmental contractility disorders and ST segment depression in ET is a feature of myocardium in SMI.

Low Levels of Vitamin D and Silent Myocardial Ischemia in Type 2 Diabetes: Clinical Correlations and Prognostic Significance.

Vitamin D deficiency has a pathogenetic and prognostic role in coronary artery disease and a key role in pain transmission. Diabetic patients have a higher risk of silent myocardial ischemia (SMI) due to diabetic neuropathy. We evaluated the correlation between SMI and Vitamin D serum levels in type 2 diabetic patients and assessed whether SMI patients had a worse survival rate than their symptomatic counterpart. We enrolled 253 patients admitted in our Cardiology Unit and compared them with 50 healthy volunteers. We created three sub-groups: symptomatic MI group (125, 32.4%); SMI group (78, 25.7%), and no-MI group (50, 41.9%). 25(OH)D levels (nmol/L) were lower in the SMI group (34.9 ± 5.8) compared to those in the symptomatic MI (49.6 ± 6.1; p = 0.01), no MI (53.1 ± 6.2; p = 0.001), and control groups (62.1 ± 6.7; p = 0.0001). 25(OH)D levels predicted SMI in diabetic patients, with an inverted odds ratio of 1.11 (p = 0.01). Symptomatic MI group survival was higher than the SMI one (6-year survival rate: 83 vs. 69%; p = 0.01). Diabetic patients with SMI had a higher mortality risk and showed lower 25(OH)D levels than the symptomatic group. This suggests the crucial role that vitamin D has in the pathogenesis of SMI.

P979 Subclinical left ventricular dysfunction and silent myocardial ischemia in asymptomatic middle-aged patients with type 2 diabetes mellitus

Abstract Early detection of silent myocardial ischemia (SMI) in asymptomatic middle-aged patients (pts) with type 2 diabetes mellitus (T2DM) may be important due to the generally poor prognosis and early myocardial involvement in this specific subgroup of diabetic population. Our goal was to evaluate whether subclinical left ventricular (LV) systolic dysfunction assessed by two-dimensional speckle-tracking echocardiography (2D-STE) is independently related to SMI detected by MPI (gated SPECT myocardial scintigraphy) and if it could provide incremental information over baseline characteristics to identify it. We have tested the hypothesis that the myocardial mechanics significantly differ in asymptomatic middle-aged diabetics, depending on the presence or absence of SMI. In total, 60 consecutive middle-aged (<60 years; 42 males, 70.0%) asymptomatic T2DM pts were enrolled into the study. MPI was performed in one-day protocol according to the EANM procedural guidelines, and SMI was diagnosed consensually by two experts as myocardial perfusion abnormalities without associated symptoms. The T2DM pts were subdivided into two groups according to the results of MPI, namely SMI group (n = 11) and non-SMI group (n= 49) Global longitudinal peak systolic strain (GLPSS) was measured from two- and four-chamber views cines using Automated Function Imaging (Vivid S6, GE). Subclinical LV dysfunction was defined as GLPSS of > -20%. Prevalence of SMI in T2DM pts was 18,3%. All pts in SMI group (n = 11) were of male gender, and disease duration ≥ 5 years. Pooled data from 2D-STE showed significant reduction in mean absolute GLPSS values (p<.001). Further more, pts in SMI group had more impaired GLPSS when compared with patients in non-SMI group (-16.1 ± 1.5% vs. -20.4 ± 1.8%, P < .01). At multivariate analysis, male gender, an amount of epicardial adipose tissue and erectile dysfunction in men were independently associated with SMI. The addition of the LV GLPSS values to other selected independent clinical variables significantly improved the ability to predict SMI in these patients (χ(2) = 48.62; P = .001). Asymptomatic middle-aged T2DM pts with SMI showed a more impaired LV GLPSS compared with patients without silent ischemia. The presence of subclinical LV systolic dysfunction provides significant incremental value for the identification of SMI in asymptomatic middle-aged diabetics.

P5480Impact of Silent Myocardial Ischemia on One Year Mortality after Successful Coronary Intervention: Data from Japanese Multicenter (KICS) Registry

Abstract Introduction Under the awareness of appropriate use criteria, the significance of PCI for the patients with silent myocardial ischemia (SMI) decreases. On the other hand, the prognoses of SMI patients have been reported to be equivalent to those of symptomatic effort angina pectoris (EAP) patients. We aimed to clarify the prognosis of SMI after PCI and elucidate the factors influencing the mortality. Methods The Kumamoto Intervention Conference Study is multicenter registry enrolling consecutive patients undergoing PCI in 16 centers in Japan. Overall, 17,688 consecutive patients were enrolled during April 2008 to March 2017. To compare the clinical events between SMI and EAP, 8,278 subjects, excluding acute coronary syndrome, post successful PCI were enrolled with 1-year follow-up data. Results In this study, 2,071 patients were classified as SMI and 6,207 patients were EAP. Male, lower body mass index (BMI), diabetes, chronic kidney disease (CKD), smoking habits, prior myocardial infarction (MI), composite of cerebrovascular disease and composite of peripheral arterial disease were all significantly higher in the SMI group. Although nonfatal MI and stent thrombosisduring 12-monthswere comparable between the 2 groups, all-cause mortality and cardiac death during 12-months were significantly higher in the SMI group than in the EAP group (3.9% vs 1.8%, p<0.001, 1.4% vs 0.5%, p<0.001, respectively). On the other hand, Repeat Revascularization rate during 12-months was significantly lower in the SMI group than in the EAP group (15.7% vs 19.5%, p<0.001).Kaplan-Meier analysis for cardiac death showed a significant difference between the 2 groups (Figure). In a multiple logistic regression analysis, in addition to lower BMI and CKD, SMI was an independent predictor for cardiac death. Even after adjustment by propensity-score matching with predictive factors for cardiac event, SMI showed a higher cardiac death rate compared with EAP (1.4% vs 0.5%, p=0.004), and it remained as a significant predictor. Conclusion In this study, SMI itself was associated with higher mortality after PCI. Strict follow-up and assessment of residual ischemia should be necessary for SMI patients.

Evaluation of three-dimensional speckle tracking echocardiography to left ventricular rotation and twist in patients with silent myocardial ischemia

To analyze the characteristics of left ventricular rotation and twist in patients with silent myocardial ischemia (SMI) by three-dimensional speckle tracking echocardiography (3D-STE), and to explore the diagnostic value of this method for SMI. According to Gensini score, 66 patients with SMI were divided into 3 subgroups: a mild lesion group (n=16), a moderate lesion group (n=26) and a severe lesion group (n=24). Thirty patients with negative results in selective coronary angiography served as a control group. The parameters of wall motion score index (WMSI), left ventricular ejection fraction (LVEF), peak basal rotation (Ptw-B), peak apical rotation (Prot-A), left ventricular peak apical rotation (LVrot), left ventricular peak apical twist (LVtw) were measured. In the SMI group, with an increase in severity of myocardial ischemia, LVEF, Prot-A, Prot-B, LVrot, LVtw showed a decrease trend while WMSI exhibited an opposite phenomenon (P<0.05), and all of them displayed a significant corelation with Gensini score (P<0.05). In the diagnosis of SMI, all of the above-mentioned parameters were highly sensitive and specific. 3D-STE showed the highest diagnostic value for LVtw. Left ventricular rotation and twisting motion monitered by 3D-STE can evaluate the severity of myocardial ischemia in patients with SMI.

A New Metabolic Mechanism for Absence of Pain in Patients with Silent Myocardial Ischemia

We undertook this study to detect if there is a relationship between lactate production in the myocardium and the presence or absence of chest pain in patients with coronary artery disease (CAD). Forty six patients with significant CAD including left anterior descending artery underwent echocardiography study, coronary angiography and pacing-induced ischemia. Serum lactate levels were determined in four blood samples, from mid-LV cavity and from coronary sinus before and after pacing-induced ischemia. Twenty eight patients comprised angina group and 18 patients comprised silent myocardial ischemia (SMI) group during pacing-induced ischemia. Eighteen patients (64.3%) of angina group had lactate production during ischemia. Eighteen patients of SMI group (100%) had diminished lactate extraction, and none had lactate production. The novel finding of this study is that the major difference in metabolism during SMI and angina pectoris is in the state of lactate production, which is absent during SMI and present during angina. We assume that lactate is the stimulus of cardiac ischemic pain and when its level increases, it stimulates pain receptors leading to chest pain.

Heart Rate Recovery After Exercise Is a Predictor of Silent Myocardial Ischemia in Patients With Type 2 Diabetes

OBJECTIVESlow heart rate recovery (HRR) predicts all-cause mortality. This study investigated the relationship between silent myocardial ischemia (SMI) and HRR in type 2 diabetes.RESEARCH DESIGN AND METHODSThe study enrolled 87 consecutive patients with type 2 diabetes and no chest symptoms. They underwent treadmill exercise testing and single-photon emission computed tomography imaging with thallium scintigraphy. Patients with abnormal myocardial perfusion images also underwent coronary angiography.RESULTSSMI was diagnosed in 41 patients (47%). The SMI group showed slower HRR than the non–SMI group (18 ± 6 vs. 30 ± 12 bpm; P < 0.0001). HRR was significantly associated with SMI (odds ratio 0.83 [95% CI 0.75–0.92]; P = 0.0006), even after adjustment for maximal exercise workload, resting heart rate, maximum heart rate, rate pressure product, HbA1c, use of sulfonamides, and a history of cardiovascular disease.CONCLUSIONSHRR can predict SMI in patients with type 2 diabetes.

Insertion/insertion genotype of α 2B-adrenergic receptor gene polymorphism is associated with silent myocardial ischemia in patients with type 2 diabetes mellitus

Objectives We investigated whether α 2-adrenergic receptor (AR) polymorphisms (α 2A-AR, α 2B-AR and α 2C-AR gene) affected silent myocardial ischemia (SMI) in patients with type 2 diabetes mellitus (T2DM). Design and methods Genetic polymorphisms were determined in 321 patients with T2DM and coronary artery disease (CAD). Among them, 129 patients experienced transient asymptomatic ST-depression during 24-hour ambulatory electrocardiogram (SMI group), and the remaining 192 patients who had ambulatory electrocardiogram-symptom matching angina were categorized as angina group. Results The genotype distribution and allele frequencies of α 2B-AR gene polymorphism (insertion [I]/deletion[D]) exhibited significant difference between SMI group and angina group (both P < 0.05), with genotype II (34.9%) being higher in SMI group than in angina group (19.8%)(P < 0.01). Multivariable logistic regression analysis revealed that duration of diabetes and genotype II of α 2B-AR gene polymorphism were independently associated with SMI. Conclusions Homozygote for I allele of α 2B-AR gene polymorphism is associated with SMI in T2DM patients with CAD.

Silent myocardial ischemia and cardiovascular responses to anger provocation in older adults

To determine if older, asymptomatic individuals with no prior history of coronary heart disease with exercise-induced silent myocardial ischemia (SI) during graded exercise treadmill testing exhibit exaggerated cardiovascular reactivity to anger provocation, we compared 42 SI participants and 95 controls. Systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) changes from baseline to three tasks--anger recall, speech role-play, and mental arithmetic with harassment--were assessed. Compared to controls, SI displayed greater HR responses for the speech role-play task only. The SI group was significantly older, had higher levels of fasting glucose and triglycerides, and had lower HDL-cholesterol. In multiple regression analyses, after controlling for these differences, SI was significantly associated with greater HR responses to the speech role-play. In sum, the SI group significantly exaggerated HR responses to the speech role-play task, whereas SBP and DBP reactivity were comparable between groups. This suggests minimally enhanced cardiovascular reactivity among older SI patients that may nonetheless increase risk for cardiac events.

Silent Myocardial Ischemia Is Associated with Autonomic Neuropathy and Other Cardiovascular Risk Factors in Type 1 and Type 2 Diabetic Subjects, Especially in Those with Microalbuminuria

The prevalence of silent myocardial ischemia (SMI) seems to be above average in diabetic subjects. As routine screening is costly, identifying high-risk populations is mandatory. This study aimed to estimate the prevalence of SMI in diabetic subjects and in controls and to define the diabetic population at risk. We studied 353 asymptomatic caucasian subjects (217 with diabetes and 136 controls matched by age, sex, and cardiovascular risk factors) with normal resting ECG. The diabetic group included 39 type 1 and 178 type 2 diabetics (age 57 +/- 11 yr, 162 males/55 females). Subjects performed the Treadmill Test (TT) and, when abnormal, underwent single-photon emission computed tomography (SPECT) with exercise testing or dipyridamole injection. Coronary angiography was performed if the SPECT was suggestive of ischemia. TT was positive in 16 (8.5%) diabetics: 3 with type 1 and 13 with type 2. No controls had positive TT. SPECT was performed in 13 subjects and was positive in 10; angiography was performed in 7 and identified significant lesions in all cases. Patients with SMI were older and had a higher prevalence of autonomic neuropathy, hypertension, and dyslipidemia than those without. Microalbuminuria was also higher in the SMI group (613 +/- 211 vs 72 +/- 245 mg/d; p < 0.05). We conclude that diabetic patients aged over 60 with autonomic neuropathy and other cardiovascular risk factors should be screened for the presence of SMI especially if they have increased microalbuminuria.

Apoε 4 allele increases the risk for exercise-induced silent myocardial ischemia in non-insulin-dependent diabetes mellitus

Objective: To examine whether the Apoε 4 allele is associated with an increased risk for exercise-induced silent myocardial ischemia (SI) in non-insulin-dependent diabetes mellitus (NIDDM). Methods: One-hundred and sixty-six NIDDM patients with normal rest electrocardiography were selected randomly. Of them, 77 cases were SI, and 89 without SI. Seventy-two healthy individuals without SI were also selected as controls. Polymerase chain reaction/ASO probes was used to determined their mouthwash DNA apolipoprotein E genotypes. Results: (1) In the NIDDM with SI group, the prevalence of ε 4/ 3 was 31.2%, which was significantly higher than 9.7% in control and 7.9% in NIDDM without SI ( P<0.005). ε 3/ 3 was 55.8%, which was significantly lower than 73.6% in control and NIDDM without SI ( P<0.05). (2) In the NIDDM without SI group, ε 4/ 3 was 7.9%, which was significantly lower than 18.7% in NIDDM ( P<0.05). In addition, the ε 4 allele prevalence was 19.5%, which was significantly higher than 5.6% in NIDDM without SI ( P<0.005), and 9% in control, 12% in NIDDM ( P<0.05). (3) In the ε 4/ 3ε 4/ 4 group for NIDDM, the prevalence of SI was 77%, which was significantly higher than 39% in the ε 3/ 3 group and 29% in the ε 2/ 2ε 3/ 2 group ( P<0.005). Conclusion: The ε 4 allele increases the risk for SI in NIDDM.

Prognostic Indicators of Major Cardiac Events in Patients with Asymptomatic Coronary Artery Disease.

We investigated the role of myocardial ischemia in acute myocardial infarction and cardiac death in 253 patients with asymptomatic coronary disease (206 men, 47 women, mean age: 55 +/- 8 years). Patients were divided into two groups: those with angina pectoris with no history of myocardial infarction (AP group, 93 patients) and those with a history of myocardial infarction (MI group, 160 patients). We also examined the usefulness of exercise electrocardiographic and Holter electrocardiographic findings as prognostic indicators of cardiac events. After 24-hour Holter electrocardiograms were obtained in both groups, patients were assigned to subgroups with or without silent myocardial ischemia (SMI) based on the presence or absence of transient ST-segment depression. Prognostic indicators were evaluated by multiple regression analysis. Cardiac events occurred in 26 (10.3%) of 253 patients; in 6 patients these events were fatal. The incidence of cardiac events was significantly higher in the SMI group than in the non-SMI group (16.4% versus 5.6%, p < 0.05). SMI was identified as a significant prognostic indicator in the overall population (p = 0.0088), as were the number of diseased coronary arteries in the AP group (p = 0.0152), and SMI (p = 0.0022) in the MI group. There were 3 deaths related to cardiac events in each group. The mean time from onset of angina pectoris to death was 73 +/- 41 months compared with 33 +/- 43 months in the MI group. Our findings suggest that the severity of the coronary lesion and SMI were important predictors of major cardiac events, and that the mechanism of the onset of cardiac events was different in the AP and MI groups.

The causes and clinical significance of exercise-induced silent myocardial ischemia evaluated by ischemic range and intensity with exercise Tl-201 myocardial SPECT.

We investigated the causes and long-term prognosis of exercise-induced silent myocardial ischemia (SMI) by means of exercise Tl-201 myocardial SPECT (Ex-SPECT) in 97 patients with effort angina or old myocardial infarction (OMI). These patients were proven to have significant stenosis by coronary angiography. The subjects were divided into three groups based on the presence or absence of Tl-201 redistribution or angina during exercise testing. Group one consisted of 34 patients who had redistribution on Ex-SPECT and angina during exercise testing: the painful myocardial ischemia (PMI) group. The second group consisted of 38 patients who had redistribution on Ex-SPECT, but no angina during exercise testing: the SMI group. The third group consisted of 25 patients who had no redistribution: the RD (-) group. The ischemic range and intensity were quantified by the defect volume ratio (DVR) and defect severity index (DSI), respectively. Comparison of the DVR and DSI values for the PMI and SMI groups revealed that the DVR and DSI values for the SMI group were lower than those of the PMI group. Also the prognosis of the SMI group tended to be worse than that of the RD (-) group. Thus, we concluded that the SMI and PMI group should receive identical treatment.

Clinical and prognostic significance of silent myocardial ischemia in survivors after acute myocardial infarction.

To clarify the clinical and prognostic significance of silent myocardial ischemia (SMI) after acute myocardial infarction (MI), the clinical characteristics and long-term prognosis after discharge in 525 medically treated survivors after acute MI were investigated. According to the presence of post-infarction angina and results of all exercise tests during hospitalization, 309 patients without ischemic episodes were classified into control group, 59 patients with SMI into SMI group and 157 patients with post-infarction angina into AP group. Previous MI (29%, 24%, 11%, respectively), non-Q wave MI (34%, 34%, 15%) and multivessel disease (69%, 61%, 33%) were more frequent in the SMI and AP groups than in the control group. These indicated clinical characteristics in patients with SMI were similar to those in patients with angina pectoris. The incidence of angina prior to MI onset in patients with SMI was lower than in patients with post-infarction angina. This may suggest that there is some common mechanism keeping them silent in the pre- and post-MI period. During the mean follow-up period of 5.5 years, 93 patients died and 78 had a recurrent MI. Cumulative total and cardiac mortality, and incidence of recurrent MI by actuarial method were higher in the SMI as well as AP group than in the control group. There was no statistically significant difference in prognosis between SMI and AP group. We conclude total ischemic burden, not only symptomatic but SMI, should be treated using currently available therapeutic modalities for further improvement of long-term prognosis in survivors after acute MI.