Incidence Of Silent Myocardial Ischemia Research Articles

Silent Myocardial Ischemia in Diabetes: A Critical Review of Risk Factors and Screening Strategies

Silent Myocardial Ischemia is frequent amongst diabetics as result of autonomic dysfunction and loss of pain alert mechanism. Type 2 Diabetes Mellitus patients have a higher incidence of Silent myocardial ischemia, which leads to poorer long-term cardiovascular outcomes. Cardiovascular disease is the dominant source of mortality and morbidity in diabetics. There are numerous risk factors associated with Silent myocardial ischemia in diabetes that requires earlier screening in order to prevent unexpected cardiovascular mortality, as 50% to 80% of all heart attacks are silent in nature. To achieve the suggested control over glycaemia, blood pressure, and lipids, more focus is required on guidelines-directed therapy. Conclusion: We observed that type 2 diabetics were more likely than type 1 diabetics to experience Silent myocardial ischemia. The majority of instances were observed in male patients, over 50 years of age and in patients with type 2 diabetes mellitus for 5 to 10 years. Keywords: Coronary artery disease, Dyslipidaemia, Pulmonary hypertension, Aspirin, Macrophages, Hyperglycemia

Influence of sex on the incidence of potential coronary artery disease and long-term outcomes in asymptomatic patients with diabetes mellitus

BackgroundDiabetic patients often have coronary artery disease (CAD) without symptoms. It is known that females tend to have silent or less chest pain and worse prognoses when they develop acute coronary syndrome. Thus, sex differences may impact long-term outcomes in diabetes mellitus (DM) patients with silent myocardial ischemia (SMI). The present study aimed to assess the influence of sex on long-term outcomes in DM patients with SMI. MethodsA total of 461 consecutive asymptomatic and self-sufficient DM patients seen at our hospital from 2011 to 2017 were prospectively reviewed. Patients underwent an ergometer exercise test. When the exercise test was positive or the patient could not achieve 90% of their target heart rate, coronary angiography was performed. The primary endpoint was major adverse cardiac and cerebrovascular events (MACCEs), including death, non-fatal myocardial infarction, and stroke. ResultsSMI was diagnosed in 81 patients. The median follow-up duration from diagnosis was 35 (15–57) months. The incidence of SMI was similar in females and males [34/170 (20%) vs. 47/291 (16.2%), p = 0.36]. Enrolled patients were divided into four groups according to sex and the presence/absence of SMI. Female patients with SMI showed worse clinical outcomes. After adjustment for age and coronary risk factors, female SMI was independently associated with MACCEs [hazard ratio 2.59, 95% confidence interval 1.07–5.68, p = 0.024], while male SMI was not. ConclusionsFemale SMI was associated with worse long-term outcomes in DM patients. Early diagnosis of potential SMI and appropriate care are required in female DM patients. (UMIN000038340).

P1525Impact of renal function on silent myocardial ischemia and long-term outcomes in asymptomatic patients with diabetes mellitus

Abstract Introduction Coronary artery disease (CAD) is a major cause of the morbidity and mortality in diabetic patients, however aggressive screening for CAD in asymptomatic patients is not recommended in guidelines. Chronic kidney disease (CKD) is one of serious co-morbidity and such patients especially tends to be observed without angiography to avoid contrast induced nephropathy. It is well known that systemic atherosclerosis worsens renal function. Thus, chronic kidney disease (CKD) may be associated with potential myocardial ischemia and worse clinical outcomes in asymptomatic DM patients. Purpose To determine the impact of CKD on the incidence of silent myocardial ischemia (SMI) and the long-term outcomes in asymptomatic patients with DM. Methods A total of 461 consecutive patients with DM were prospectively studied from July 2011 to August 2017. All patients were asymptomatic and self-sufficient in daily life. They underwent the ergometer exercise test. Coronary angiography was performed when the stress test was positive, or the patients did not achieve 90% of target heart rate. Primary end point was major adverse cardiac and cerebrovascular events (MACCE) including death, non-fatal myocardial infarction and stroke. Results SMI was diagnosed in 81 patients. The incidence of SMI increased with higher stage of CKD as shown in Figure. The median follow-up duration from diagnosis was 35 (15–57) months in the overall cohort of 461 diabetic patients. SMI patients had worse clinical outcomes (Figure). Among 81 patients with SMI, severe CKD group (≥ stage 3a) had worse long-term outcomes. After adjustment of age, gender and coronary risk factors, eGFR was independently associated with MACCE in diabetic patients with SMI [HR0.96, 95% CI (0.923–0.996), p=0.028]. Incidence of SMI and Kaplan-Meier curves Conclusions The incidence of potential CAD was high in CKD and the long-term outcomes of those patients were poor in asymptomatic DM. CKD patients should be aggressively screened for CAD and more intensively treated in our daily practice of DM.

Effects of dexmedetomidine on perioperative cardiac adverse events in elderly patients with coronary heart disease

To investigate the effects of dexmedetomidine on perioperative cardiac adverse events in elderly patients with coronary heart disease. Methods: Sixty elderly patients, who were diagnosed as coronary heart disease and underwent gastric cancer operation, were randomly divided into 2 groups (n=30): the dexmedetomidine group (Dex group) and the control group. In the Dex group, dexmedetomidine was administered intravenously at 0.5 μg/(kg·h) after a bolus infusion at 0.5 μg/kg for 10 min before anesthesia induction. In the control group, equal volume of normal saline was infused instead of dexmedetomidine. The 2 groups received the same anesthesia treatment. The venous bloods were collected at the preoperative 0 h and postoperative 24 h. The concentrations of cardiac troponin (cTnI), N-terminal pro-brain natriuretic peptide (NT-proBNP) and hypersensitive C-reactive protein (hs-CRP) were determined. The ECG was monitored at the above time and the postoperative incidence of cardiac adverse events was recorded. Results: The levels of cTnI, NT-proBNP and hs-CRP in serum were elevated in the 2 groups after the operation. Compared with the control group, the levels of cTnI, NT-proBNP and hs-CRP were significantly decreased in the Dex group (P<0.05). Compared with the control group, the incidence of bradycardia were significantly increased, while the myocardial ischemia and tachycardia were significantly decreased in the Dex group during the operation (P<0.05); the incidence of silent myocardial ischemia and arrhythmia was significantly reduced at 3 days after operation in the Dex group (P<0.05). Conclusion: Dexmedetomidine could decrease the incidence of cardiac adverse events in elderly patients with coronary heart disease.

Screening for the Presence of Coronary Artery Disease

Screening for the Presence of Coronary Artery Disease

Isquemia silenciosa na doença coronariana estável em vigência de tratamento medicamentoso

Few data are available on the behavior of myocardial ischemia during daily activities in patients with coronary artery disease receiving antianginal drug therapy. To study the mechanism generating myocardial ischemia by evaluating blood pressure and heart rate changes in patients with stable atherosclerotic disease receiving drug therapy and with evidence of myocardial ischemia. Fifty non-hospitalized patients (40 males) underwent 24-hour electrocardiographic monitoring synchronized with blood pressured monitoring. Thirty five episodes of myocardial ischemia were detected in 17 patients, with a total duration of 146.3 minutes; angina was reported in five cases. Twenty nine episodes (100.3 minutes) occurred during wakefulness, with 11 episodes (35.3 + 3.7 min) in the period from 11 a.m. to 3 p.m. Blood pressure and heart rate evaluation in the three ten-minute intervals following the ischemic episodes showed a statistically significant difference (p< 0.05), unlike that shown for the three intervals preceding the episodes. However, during the ischemic episode, a higher than 10-mmHg elevation in blood pressure and 5 beats per minute in heart rate were observed when compared with the time interval between 20 and 10 minutes before the episode. The mean heart rate at the onset of ischemia during the exercise test performed before the study was 118.2 + 14.0, and 81.1 + 20.8 beats per minute on the 24-hour electrocardiogram (p < 0.001). The incidence of silent myocardial ischemia is high in stable coronary artery disease and is related to alterations in blood pressure and heart rate, with different thresholds for ischemia for the same patient.

Silent myocardial ischemia in diabetic and nondiabetic patients with coronary artery disease

Background: Patients with diabetes mellitus are at increased risk for CAD; silent ischemia is reported to be frequent in diabetic populations. The aim of the present study was to evaluate the prevalence of silent ischemia in diabetic and nondiabetic patients with assessed CAD. Methods and results: We recruited a total of 618 patients with CAD: 309 were consecutive diabetic patients and 309 were age- and gender-matched nondiabetic patients. Myocardial ischemia was evaluated both during daily life and during exercise testing. Angina pectoris during daily life was more frequent in diabetic than in nondiabetic patients (80% vs. 74%, P<0.05). The anginal pain intensity either during daily life or acute myocardial infarction (MI), the prevalence of a previous MI, the extent of CAD and ergometric parameters were similar in diabetics and nondiabetics. Silent ischemia during exercise was documented in 179 (58%) diabetics and in 197 (64%) nondiabetics (nonsignificant, ns). Both diabetics and nondiabetics with silent exertional myocardial ischemia differed from symptomatic subjects in higher heart rate values ( P<0.01), systolic blood pressure ( P<0.01), rate–pressure product ( P<0.001), work load ( P<0.01) and maximum ST-segment depression at peak exercise ( P<0.05). Conclusions: The incidence of silent myocardial ischemia during exercise was similar in diabetic and nondiabetic CAD patients. Surprisingly, diabetics showed a higher prevalence of angina pectoris during daily activity than nondiabetics. A significant association between the presence of symptoms during daily life and exercise was observed in both groups. Our results may contribute to the planning of the clinical management of diabetic CAD patients and confirm the individual attitude to pain of CAD patients independent of the presence of diabetes.

High incidence of silent myocardial ischemia in elderly patients with non insulin-dependent diabetes mellitus

The present study was designed to reveal the incidence of silent myocardial ischemia in asymptomatic elderly non-insulin-dependent diabetic (NIDDM) patients (aged over 60 years). As a first step screening, maximal treadmill exercise test was performed. Of 140 patients studied, 54 (38.6%) were unable or not expected to achieve diagnostic levels of exercise during treadmill testing. A positive exercise test was noted in 39 of 86 (45.3%) subjects. As a second step examination, dipyridamole thallium scintigraphy was performed for 93 subjects who exhibited a positive exercise test and could not perform a maximal exercise test. Abnormal perfusion pattern was found in 39 of 93 (41.9%), who were finally considered to have a silent myocardial ischemia. Coronary angiography was performed in 18 subjects with diagnosis of silent myocardial ischemia, who gave their consent. Significant coronary artery stenosis was in fact found in 17 of 18 (94.4%) subjects studied, confirming a very high positive predictive value of this diagnostic procedure. In conclusion, elderly NIDDM patients (aged over 60 years) had an extremely high prevalence (estimated 26.3%) of silent myocardial ischemia. This evidence suggests that early and intensive detection may be needed as a part of routine care for this group.

Peri‐operative silent myocardial ischaemia in patients undergoing lower limb joint replacement surgery: an indicator of postoperative morbidity or mortality?

One hundred and twenty-seven patients undergoing major lower limb joint replacement surgery were studied to determine the incidence of silent myocardial ischemia and to ascertain any link between pre-operative cardiac risk factors, silent myocardial ischaemia and postoperative morbidity. Patients underwent ambulatory ECG monitoring for 4 days (on the pre-operative night and for 3 days postoperatively). Postoperative cardiorespiratory symptomatology and morbidity was assessed by questionnaire at 3 months. Eighty-seven patients had risk factors for silent myocardial ischaemia; 42 patients (30 with risk factors) had peri-operative silent myocardial ischaemia. The median ischaemic loads (range) were 1.04 (0.32-13.31) min.h-1 pre-operatively and 5.53 (0.26-56.39), 6.69 (0.04-42.71) and 1.23 (0.1-53.74) min.h-1 on postoperative days 1-3, respectively. Risk factors did not predict the occurrence of silent myocardial ischaemia or an increased ischaemic load pre-operatively or overall postoperatively. New symptoms (chest pain, palpitations, breathlessness or fatigue) were associated with both silent myocardial ischaemia and ischaemic load (p < 0.05). Thus cardiac risk factors do not predict the occurrence of silent myocardial ischaemia or adverse outcome. Peri-operative silent myocardial ischaemia was associated with increased postoperative fatigue.

Perioperative myocardial ischemia is associated with a prolonged cardiac vagal dysfunction after non-cardiac surgery.

Heart rate variability (HRV), a measure of cardiac autonomic balance seems to be linked to coronary artery disease (CAD). Impaired vagal input facilitates the generation of fatal arrhythmias and has a great impact on morbidity and mortality. The purpose of this study was to determine the relationship between perioperative HRV and the incidence of silent myocardial ischemia (SMI) and ventricular dysrhythmias in CAD-patients undergoing non-cardiac surgery. 31 patients were studied by continuous Holter electrocardiography preoperatively and again on the evening before surgery until postoperative day 3. Three frequency and one time domain measures of HRV (TP, 0.01-1.00 Hz: total power of the amplitude spectral plot; LF, 0.04-0.15 Hz: low-frequency power; HF, 0.15-0.40 Hz: high-frequency power; MeanRR: mean of all coupling RR-intervals between normal beats) as well as ischemic events and ventricular couplets and runs were computed. Depending on the presence of ischemic episodes, each patient was assigned to either the no SMI-group (13 pts) or the SMI-group (18 pts). MeanRR, TP and LF significantly declined in both groups over time. The parasympathetically dominated index HF, however, only decreased in the SMI-group. Normalized HF power (HF/TP) even increased in the no SMI-group resulting in a postoperative decrease in LF/HF ratio. TP, LF, and HF inversely correlated with ischemia parameters whereas HF/TP and HF/LF ratio correlated with the number of ventricular couplets. Incidence and severity of SMI significantly increased after surgery. Postoperatively, a prolonged vagal withdrawal occurred in CAD-patients exhibiting perioperative SMI. Whether the increased incidence of SMI after surgery in conjunction with the observed parasympathetic derangement contributes to adverse cardiac outcome still has to be determined.

Myocardial ischemia during the weaning period

To estimate the incidence of silent myocardial ischemia, its pattern over time and its relationship to the time and mode of weaning high-risk cardiac patients after noncardiac surgery. Prospective study with random assignment to one of three weaning modes. A surgical intensive care unit in a university hospital and a Veterans Administration hospital. Sixty-two patients meeting standard criteria for extubation were randomized to one of three modes of weaning: synchronized intermittent mandatory ventilation (n = 19), T-Bar (n = 21) or continuous positive airway pressure (n = 22). Ischemia was monitored with a continuous two-lead (V5, III) ST segment analyzer. Tracings were reviewed by a cardiologist. Ischemia was defined as greater than 1 mm ST segment depression 60 milliseconds after the J point. The monitoring period included a prewean (mean 654.0 minutes), wean (mean 46.5 minutes) and postwean (mean 1223.4 minutes) period. Of 62 patients, 12 (19.3%) experienced ischemia at some time during the monitoring period, most often during the weaning period. Ischemia during weaning was detected in 3 of 21 (14.3%) T-Bar patients and 2 of 22 (9.1%) continuous positive airway pressure patients but in no synchronized intermittent mandatory ventilation patients. This study demonstrates that silent myocardial ischemia occurs frequently in high-risk postoperative patients, with the highest incidence during weaning.

狭心症および心筋梗塞患者の予後に及ぼす無症候性心筋虚血の臨床的意義

The purpose of this study is to increase understanding of the prognosis of coronary artery disease (CAD) patients whose anginal symptoms have been removed by medical therapy, and to evaluate the prognostic and clinical significance of silent myocardial ischemia (SMI). Cardiac events including cardiac death, acute myocardial infarction, PTCA/CABG and unstable angina were examined in 253 CAD patients who underwent ambulatory Holter monitoring, treadmill exercise testing and coronary angiography. The subjects were classified into two groups: 93 patients with exertional angina (AP) without previous myocardial infarction and 160 patients with old myocardial infarction (MI). SMI was diagnosed by Holter monitoring. Cox's proportional hazard regression model and the survival curves using the Kaplan-Meier method were used to analyze 9 variables in patients with AP, including Holter monitoring parameters, exercise parameters and angiographic findings, and 12 variables in patients with MI, including the same parameters as in AP patients. The cardiac event rate was 19% in patients with AP and 18% in patients with MI. The independent and common predictors of unfavorable outcome in both groups were severe coronary lesion and SMI. The incidence of SMI was 30% in AP patients and 38% in MI patients, the same incidence as reported in previous studies. The cardiac event rate in patients with SMI was higher than in those without SMI for both groups (28% vs 9% and 32% vs 9%; p less than 0.05). However, the most frequent cardiac event was different in the groups with SMI: PTCA/CABG in AP patients and re-infarction in MI patients. The significant predictors of cardiac events in patients with SMI were severe coronary lesion, short exercise duration, severe asynergy and exercise-induced angina in patients with AP and lower ejection fraction and maximum ST depression on Holter monitoring in patients with MI. In conclusion, it was ascertained that SMI is a significant and independent marker of unfavorable outcome in patients with CAD and that the cardiac event rate in patients with SMI was significantly higher than in those without SMI. However, severe complications such as acute myocardial infarction were more frequent in MI patients than in AP patients. Therefore, it was suggested that the use of re-vascularization procedure (PTCA/CABG) should be considered as soon as possible in patients with SMI, regardless of whether anginal symptoms are present or not.(ABSTRACT TRUNCATED AT 400 WORDS)

Silent myocardial ischemia and infarction in diabetics with peripheral vascular disease: Assessment by dipyridamole thallium-201 scintigraphy

We investigated the incidence of silent myocardial ischemia and infarction as assessed by dipyridamole thallium scintigraphy in 30 diabetic patients with peripheral vascular disease and without clinical suspicion of coronary artery disease. Seventeen patients (57%) had thallium abnormalities, with reversible thallium defects compatible with ischemia in 14 patients (47%) and evidence of prior, clinically silent myocardial infarction in 11 patients (37%). Thallium abnormalities were most frequent in patients with concomitant hypertension and cigarette smoking ( p = 0.001). These results suggest that unsuspected coronary artery disease is common in this particular group of patients with diabetes mellitus.

Current concepts of silent myocardial ischemia

The definition, pathogenesis, incidence and characteristics, detection, treatment, and prognosis of silent myocardial ischemia (SMI) are reviewed. SMI is the occurrence of myocardial ischemia for which there is objective evidence (electrophysiological, hemodynamic, and metabolic changes) but no angina. Patients with SMI are classified as type 1 (completely asymptomatic), type 2 (SMI after myocardial infarction), and type 3 (both symptomatic and silent ischemia). Episodes of SMI are true ischemic events. The absence of pain may be due to defects in pain perception, an altered physiological response to ischemia, or a lesser degree of ischemia. The incidence of SMI is 2-5% in totally asymptomatic patients, 20-30% in patients who have suffered myocardial infarction, and 44-84% in patients who have symptomatic ischemia. SMI can be detected by exercise testing, portable electrocardiographic monitoring, or imaging techniques. Patients with SMI have more frequent adverse cardiac events (except death) than patients without SMI. The frequency of adverse cardiac events is similar in patients with angina and patients with SMI. SMI has been treated with nitrates, calcium-channel blockers, and beta blockers. Beta blockers appear to be the most consistent in reducing the number and duration of episodes. Combination therapy with beta blockers and nifedipine may be more effective than therapy with either agent alone. Because of the limited number of studies and the possible contribution to the results of spontaneous variability in the occurrence of SMI, no definite conclusions can be drawn about drug efficacy. There is no evidence that the prognosis of patients with SMI is altered by drug therapy; routine treatment with anti-ischemic drugs cannot be recommended. Patients must be evaluated individually, with aggressive management being reserved for those at high risk for myocardial infarction or other serious cardiac events.

栃木県Ｉ町の循環器集団検診における心エコー法の有用性

The purpose of this investigation was at first to clarify the clinico-epidemological characteristics of hypertension in Tochigi Prefecture, especially in Ishibashi Town, second to examine the usefulness of echocardiography in a community survey on cardiovascular diseases. The results were as follows: 1. The trends of mortality of hypertensive heart disease in Tochigi Prefecture. 1) The mortality of hypertensive heart disease in Tochigi Prefecture showed a tendency to decrease for these ten years. It was higher in Tochigi Prefecture than in all over the country. 2) The survey of National Health Insurance records in Ishibashi Town revealed that 56.6% of the patients with cardiovascular disease accompanied with hypertension. 2. The epidemiological findings on cardiovascular diseases in Tochigi Prefecture as compared with those all over the country. 1) The averages of systolic and diastolic blood pressure were lower. 2) The incidence of left ventricular highvoltage and ST-T change in electrocardiography was higher. 3) The incidence of myocardial infarction and angina pectoris was lower. 4) The incidence of silent myocardial ischemia was higher. 5) There was no difference of hypertensive heart disease between in Tochigi Prefecture and all over the country. 3. The multivariate analysis of findings of the community survey on cardiovascular disease (mainly ischemic heart disease and hypertensive heart disease) in Ishibshi Town. 1) Severity of hypertension, anamnesis of hypertension and subjective symptom of heart in relation with ischemic heart disease. 2) Anamnesis of hypertension and abnormality of electrocardiography in relation with hypertensive heart disease. These factors above mentioned were suggested to have strong relation with ischemic heart disease and hypertensive heart disease, by application of the quantification method of Hayashi's second type to data of a community survey on cardiovascualr diseases in Ishibashi Town. 4. The relation between echocardiography and blood perssure level. 1) There was a significantly clear relation between thicknes of intervascular septum and blood perssure level (p<0.01), and also between thickness of postrior wall and blood pressure level. 2) Diastolic descent rate of mitral valve made a clear decrease adversely to the level of blood pressure. 3) Partial correlation coefficient of examination items in the community survey with the level of blood pressure was the highest (0.42) in thickness of intervascular septum of echocardiography, secondly higher (0.33) in anamnesis of hypertension and thirdly higher (0.14) in age factor. 4) Examination of pertial correlation coefficient of those factors by age revealed that in age group from 30 to 59, thickness of intervascular septum of echocardiography had the highest correlation (0.46) with blood pressure level and in age group more than 60 anamnesis of hypertension had the highest correlation (0.60). Findings above mentioned are likely to suggest the usefulnes of echocardiography in community survey on cardiovascular diseases, as well electrocardiography and other methods of examinaiton.