Prevalence Of Myocardial Perfusion Abnormalities Research Articles

Myocardial perfusion abnormalities in Eisenmenger syndrome.

Compared to primary pulmonary hypertension (PPH), the right ventricular (RV) contractile function is preserved for a long time in patients with Eisenmenger syndrome and is likely the most important determinant of relatively higher survival. The differences in myocardial perfusion have been purported to explain this discrepancy. The exact prevalence of myocardial perfusion abnormalities in Eisenmenger syndrome is not known. We sought to examine the prevalence of myocardial perfusion abnormalities in patients with Eisenmenger syndrome. In this prospective study, 20 consecutive adult patients with Eisenmenger syndrome were subjected to clinical assessment, six-minute walk test and echocardiography. Myocardial perfusion was assessed using one day stress-rest Gated Technetium-99 m Sestamibi single-photon emission computed tomography. Nineteen (95%) patients were in New York Heart Association functional class I or II. All patients had RV hypertrophy. Five (25%) patients had RV systolic dysfunction. Left ventricular systolic function was normal in all except in three patients. Two (10%) patients had perfusion defects in the RV and 4 (20%) patients had perfusion defects in the left ventricle (LV). Myocardial perfusion defects, both in RV and LV, occur even in asymptomatic or mildly symptomatic patients with Eisenmenger syndrome.

Myocardial Perfusion Abnormalities in Young and Premenopausal Women with Systemic Lupus Erythematosus, Detected with 99MTC MIBI Myocardial Perfusion Scintigraphy - Prevalence and Correlation with Proatherogenic Factors.

Atherosclerosis in young and premenopausal women with systemic lupus erythematosus (SLE) is frequent, premature and progressive. Although asymptomatic or with atypical clinical presentation, the patients are at high risk of cardiac events. Aim of this study is to estimate the risk profile for atherogenesis and the prevalence of myocardial perfusion abnormalities with 99mTc myocardial perfusion scintigraphy (MPS) in young and premenopausal women. Sixty female patients, aged 30-72 years (divided into two subgroups - patients under 45 years of age and patients over 45 years), diagnosed with SLE for over of 5 years, in active phase of the disease were analyzed for disease activity scores (SLEDAI), the immunologic status of the disease (ANA and a-DNA antibodies in the serum), procoagulant tendency (antiphospholipid antibodies-APhL and lupus-anticoagulant-LAC), the activity of the inflammatory process (hsCRP), the anti-SLE therapeutic approach and the presence of traditional risk factors for atherosclerosis (BMI, smoking, hypertension, hyperlipidemia, diabetes, and familial history for the CAD). Using one-day Dipyridamol - Rest 99mTc SPECT Gated MPS SPECT the extent, severity and reversibility of myocardial perfusion abnormalities were estimated, along with summed scores at stress, rest and summed difference scores and left ventricle volumes and ejection fraction. Abnormal MPS SPECT were detected in 27/60 or in 45% of patients, with one vessel affection of 66.7% (18/27pts) of LAD and 14.8% (4/27pts) o RCA and with two vessel disease of LAD/RCA in 2/27 pts (7.4%) and LAD/Cx in 3/27pts (11.1%). Myocardial perfusion abnormalities were equally prevalent in subgroups of patients younger than 45 years (44,4%) and in patients older than 45 years (45.5%) (ns). The subgroups did not differ significantly concerning the extent of perfusion abnormalities (9,8±3.2% of LV myocardial mass vs. 9,8±7.1%,ns), their severity (with predominance of mild perfusion defects, 48,6% vs. 51,3%,ns) and reversibility (reversible in 41.3% and 58.6%, ns). The differences between the summed scores of severity and the extent of ischemia in the two subgroups were statistically nonsignificant. Younger patients had significantly higher end-diastolic, end-systolic and stroke volumes during stress and rest conditions, compared to older patients (p<0,01) although there were no differences in systolic function, which was not affected in either of the groups as expressed threw ejection fraction. Although nonsignificant, younger patients had higher values of hsCRP and higher procoagulant activity (positive aPhL, LAC) while they were with more active disease activity, with higher SLEDAI score compared to older patients (p=0.028). Higher SLEDAI score and LV volumes, especially EDV at stress were identified as predictor of abnormal MPS in younger groups and more aggressive multidrug anti SLE treatment as predictor of normal MPS. The prevalence and characteristics of myocardial perfusion abnormalities in young SLE are equal as the same in older SLE patients, which indicates the presence of premature, accelerated atherosclerosis in young cohort of patients with SLE. Younger SLE patients with pure disease control (higher SLEDAI score, less aggressive treatment, high hsCRP values and pronounced procoagulant tendency) should undergo screening for myocardial perfusion abnormalities s using 99mTc MIBI MPS).

Myocardial perfusion abnormalities in asymptomatic type 2 diabetic patients

ObjectiveThe prevalence of coronary artery disease (CAD) is high in patients with diabetes. Because ischemia and infarction are often silent in diabetic patients, diagnosis of CAD occurs inevitably late. It is essential to identify the presence of CAD in diabetic patients to start early treatment. Therefore, the aim of this study was to determine the prevalence of abnormal myocardial perfusion in asymptomatic type 2 diabetic patients using myocardial perfusion imaging. MethodsFifty-nine patients with type 2 diabetes, who did not have any history of CAD, but did have risk factors underwent myocardial perfusion single-photon emission computed tomography (SPECT) imaging using 99mTc-tetrofosmin and a 2-day stress–rest protocol. Two nuclear medicine specialists independently interpreted the images. Statistical analysis was performed to determine if there is a correlation between the presence of perfusion abnormalities and the history of diabetes (duration of disease, type of treatment, level of control, and presence and type of complications). The influence of other factors such as age, sex, smoking history, and family history of CAD, with abnormal scans were also studied. ResultsOf the 59 patients, abnormal scans were detected in 22 (37%) including 16 with reversible defects due to stress-induced ischemia. Hence the prevalence was 37%. Duration of diabetes, use of insulin, nephropathy, and neuropathy were significantly associated with abnormal scans (p=0.048, p=0.045, p=0.006, and p=0.03, respectively). Additionally, positive family history of CAD was highly associated with perfusion abnormalities (p<0.001). No significant association was found between other risk factors, such as hyperlipidemia and the presence of perfusion defects. ConclusionsWe found a high prevalence of myocardial perfusion abnormalities in asymptomatic type 2 diabetic patients. Perfusion abnormalities on myocardial perfusion SPECT images were associated with disease duration, insulin use, nephropathy, and neuropathy. Asymptomatic diabetic patients might be candidates with CAD abnormalities that can be studied using myocardial perfusion SPECT.

Radiation-induced myocardial perfusion abnormalities in breast cancer patients following external beam radiation therapy.

Radiation therapy for breast cancer can induce myocardial capillary injury and increase cardiovascular morbidity and mortality. A prospective cohort was conducted to study the prevalence of myocardial perfusion abnormalities following radiation therapy of left-sided breast cancer patients as compared to those with right-sided cancer. To minimize potential confounding factors, only those patients with low 10-year risk of coronary artery disease (based on Framingham risk scoring) were included. All patients were initially treated by modified radical mastectomy and then were managed by postoperative 3D Conformal Radiation Therapy (CRT) to the surgical bed with an additional 1-cm margin, delivered by 46-50 Gy (in 2 Gy daily fractions) over a 5-week course. The same dose-adjusted chemotherapy regimen (including anthracyclines, cyclophosphamide and taxol) was given to all patients. Six months after radiation therapy, all patients underwent cardiac SPECT for the evaluation of myocardial perfusion. A total of 71 patients with a mean age of 45.3±7.2 years [35 patients with leftsided breast cancer (exposed) and 36 patients with right-sided cancer (controls)] were enrolled. Dose-volume histogram (DVH) [showing the percentage of the heart exposed to >50% of radiation] was significantly higher in patients with left-sided breast cancer. Visual interpretation detected perfusion abnormalities in 42.9% of cases and 16.7% of controls (P=0.02, Odds ratio=1.46). In semiquantitative segmental analysis, only apical (28.6% versus 8.3%, P=0.03) and anterolateral (17.1% versus 2.8%, P=0.049) walls showed significantly reduced myocardial perfusion in the exposed group. Summed Stress Score (SSS) of>3 was observed in twelve cases (34.3%), while in five of the controls (13.9%),(Odds ratio=1.3). There was no significant difference between the groups regarding left ventricular ejection fraction. The risk of radiation induced myocardial perfusion abnormality in patients treated with CRT on the left hemi thorax is not low. It is reasonable to minimize the volume of the heart being in the field of radiation employing didactic radiation planning techniques. Also it is advisable to screen these patients with MPI-SPECT, even if they are clinically asymptomatic, as early diagnosis and treatment of silent ischemia may change the outcome.

Myocardial Perfusion Abnormalities in Patients Occurring More Than 1 Year After Successful Univentricular (Fontan Surgery) and Biventricular Repair (Complete Repair of Tetralogy of Fallot)

The outcome of children born with cyanotic congenital heart disease has markedly improved over the years. Follow up is recommended for most post-operated cases as complications may occur over long term. One of the complications is the development of ventricular dysfunction, often seen after a successful Fontan surgery (or one of its modifications) for single ventricle. The aim of this study was to determine the prevalence of myocardial perfusion abnormalities in the ventricular myocardium of asymptomatic patients, older than 8 years of age, who had earlier undergone either a univentricular palliation (modified Fontan procedure) or a biventricular repair for tetralogy of Fallot, more than a year ago. All eligible patients underwent screening electrocardiogram (to rule out rhythm disturbance) and echocardiography. Patients with ventricular ejection fraction of more than 50 % by echocardiography were included. Enrolled patients were subjected to gated stress-rest myocardial perfusion imaging using Technitium-99m tetrofosmin single photon emission-computerized tomography (SPECT). Ventricular ejection fraction was also calculated from gated rest study. For the Fontan group, we also analyzed data to see if the morphology of the systemic ventricle would make a difference as far as myocardial perfusion was concerned. Twenty-six patients were enrolled (11 had undergone Fontan surgery and 15 had complete repair of tetralogy of Fallot). Seven of 11 patients in the Fontan group had myocardial perfusion defects (63.6 %) as against none in the repaired tetralogy of Fallot group (p < 0.001). The ejection fraction was within normal range in both the groups; it was statistically higher in the post tetralogy of Fallot repair group (p < 0.04). There were two subgroups in the post Fontan group depending on the morphology of systemic ventricle-left (4 patients) and non-left (7 patients). Higher number and larger size of perfusion defects were present in the non-left ventricular systemic ventricle morphology as compared with left ventricular morphology, but this difference did not reach statistical significance. Myocardial perfusion defects are common in patients who have undergone univentricular repair more than one year ago in contrast to patients who had a biventricular repair for tetralogy of Fallot. In the Fontan group, the morphology of the systemic ventricle was not predictive of prevalence of perfusion defect.

Prevalence of myocardial perfusion abnormalities in end-stage liver disease

Background:The prevalence of coronary artery disease (CAD) in end-stage liver disease (ESLD) being evaluated for orthotopic liver transplantation (OLT) is unclear based on variable definition used for CAD.Objective:The aim of this study to investigate the prevalence of abnormal stress myocardial perfusion single-photon emission computed tomography (MPS) imaging, as a marker for CAD, among patients with ESLD who were referred for stress MPS imaging as a routine work up before OLT.Materials and Methods:This was a single-center, retrospective study. We reviewed data on 167 patients who were referred for MPS as a routine work up before OLT over the last 2 years. All patients underwent evaluation for CAD risk factors [age, hypercholesterolemia, diabetes mellitus (DM), hypertension (HTN), and smoking], and stress MPS as per standard protocol.Results:The total number of patients referred for stress MPS was 167. Seven patients (4% of total study population) were excluded from the study due to poor and/or nondiagnostic studies. 147 patients (92%) had normal, but only 13 patients (8%) had abnormal MPS scans. DM and male gender were the most independent risk factors for abnormal MPS with P value of 0.046, and 0.26, respectively. There was no significant association between the abnormal MPS result and HTN, hypercholesterolemia, smoking, age or etiology of the liver disease.Conclusion:Based on our data, the prevalence of abnormal MPS and left ventricular ejection fraction in patients with ESLD was found to be 8%. DM and male gender were the most independent predictor factors for abnormal MPS. True prevalence of CAD and usefulness of MPS in patients with ESLD can only be studied using a very large and randomized prospective study.

Identifying Which Treated Hypertensive Patients Without Known Coronary Artery Disease Should Be Tested for the Presence of Myocardial Ischemia by Perfusion Imaging

Stress dipyridamole technetium-99(m) sestamibi single photon emission computed tomographic imaging was used to study myocardial perfusion in 1116 hypertensive patients without known coronary artery disease (CAD). The test confirmed the presence of CAD in 28.9% of patients. As expected, patients with diabetes mellitus (DM) had a significantly higher prevalence of myocardial perfusion abnormalities (35.9% vs 23.9%; odds ratio, 1.79; 95% confidence interval [CI], 1.38-2.33; P<.0001) and high-risk myocardial imaging (16.4% vs 10.6%; odds ratio, 1.67; 95% CI, 1.18-2.37; P=.004) than those without DM. Odd ratios further increased, again as expected, with dyslipidemia (2.19; 95% CI, 1.54-3.12; P<.0001), peripheral arterial disease (2.61; 95% CI, 1.77-3.85; P<.0001), microalbuminuria (3.03; 95% CI, 1.91-4.82; P<.0001), and abnormal electrocardiographic findings (3.06; 1.68; 95% CI, 2.08-4.48; P<.0001). This large cohort study showed that more than 1 of 4 treated hypertensive patients have subclinical CAD. These study data should be clinically helpful in selecting hypertensive patients who are the most suitable candidates to screen for the presence of CAD.

High prevalence of myocardial perfusion abnormalities on positron emission tomography in asymptomatic persons with a parent or sibling with coronary artery disease.

We hypothesized that asymptomatic persons with a parent or sibling with coronary artery disease (CAD) have myocardial perfusion defects on positron emission tomography (PET) as markers of early CAD. After medical and family histories were recorded, 90 subjects underwent rest-dipyridamole cardiac PET perfusion imaging, including 18 index cases (a subject with CAD documented by PET and arteriography), 32 asymptomatic adults without known CAD who had a parent or sibling with CAD among these index cases, 30 asymptomatic subjects with comparable coronary risk factors without CAD or a family history of CAD, and 10 volunteer control subjects with no risk factors and no family history. PET perfusion images were quantified with automated software for size of abnormalities as percent of the cardiac image outside 95% CIs of normal controls and for severity as the lowest quadrant average relative activity. Of asymptomatic subjects with a parent or sibling with CAD (first-degree relatives), 50% had dipyridamole-induced myocardial perfusion defects that involved >/=5% of the cardiac image outside normal 95% CIs with or without other risk factors. The size of perfusion defects was larger in first-degree relatives than in control subjects (11+/-13% versus 1+/-1%, P:=0.02) and larger than in asymptomatic subjects with comparable risk factors but no family history of CAD (11+/-13% versus 5+/-6%, P:=0.02). This study documents the presence of quantitative, statistically significant, dipyridamole-induced myocardial perfusion abnormalities on PET in 50% of asymptomatic persons with a parent or sibling with CAD, independent of other risk factors, indicating preclinical coronary atherosclerosis.

Relation between exercise-induced ventricular arrhythmias and myocardial perfusion abnormalities in patients with intermediate pretest probability of coronary artery disease.

The significance of exercise-induced ventricular arrhythmias (VAs) is largely dependent on the clinical characteristics of the studied population. The relation between exercise-induced VAs and myocardial perfusion abnormalities has not yet been evaluated in a homogeneous patient population with intermediate probability of coronary artery disease (CAD). We studied 302 patients (mean age 54+/-9 years, 152 men and 150 women) with intermediate pretest probability of CAD (range=0.25-0.80, mean=0.43+/-0.20) by upright bicycle exercise stress test in conjunction with technetium-99m single-photon emission tomography (SPET) imaging. Exercise-induced VAs (frequent or complex premature ventricular contractions or ventricular tachycardia) occurred in 65 patients (22%). No significant difference was found between patients with and patient without VAs regarding the pretest probability of CAD (0.45+/-0.21 vs 0.43+/-0.20). Patients with exercise-induced VAs had a higher prevalence of perfusion abnormalities (52% vs 26%, P=0.002) and ischaemic electrocardiographic changes (31% vs 16%, P<0.05) compared to patients without VAs. A higher prevalence of perfusion abnormalities in patients with VAs was observed in both men (67% vs 35%, P<0.01) and women (38% vs 16%, P<0.05). However, the positive predictive value of exercise-induced VAs for the presence of myocardial perfusion abnormalities was higher in men than in women (67% vs 38%, P<0.05). The presence of abnormal myocardial perfusion was the only independent predictor of exercise-induced VAs (OR 2.2; 95% CI, 1.2-4.2) by multivariate analysis of clinical and stress test variables. It is concluded that in patients with intermediate pretest probability of CAD, exercise-induced VAs are predictive of a higher prevalence of myocardial perfusion abnormalities in both men and women. However, the positive predictive value of exercise-induced VAs for perfusion abnormalities is higher in men. Because of the underestimation of ischaemia by electrocardiographic changes, exercise-induced VAs should be interpreted as a marker of a higher probability of CAD.

Myocardial perfusion abnormalities in treated hypertensive patients without known coronary artery disease.

Myocardial perfusion abnormalities may occur in hypertensive patients in absence of significant coronary artery disease. However, it is not well established whether hypertensive patients without known coronary artery disease have a higher prevalence or extent of myocardial perfusion abnormalities compared with normotensive patients with similar clinical features. This study compares the prevalence and extent of rest and stress-induced myocardial perfusion abnormalities in patients with and without hypertension. Dobutamine (up to 40 microg/kg per min) stress technetium-99m myocardial perfusion SPECT imaging was performed for evaluation of myocardial ischaemia in 350 patients (mean age = 60+/-13 years, 146 men) without known coronary artery disease. One hundred and forty-eight patients were hypertensive. Rest SPECT images were acquired 24 h after the test Abnormal perfusion was defined as the presence of reversible or fixed perfusion defects. No significant difference was detected between patients with and without hypertension regarding gender, prevalence of symptoms, risk factors, pretest probability of coronary artery disease (52+/-28 versus 53+/-29%), peak rate pressure product (21040+/-4755 versus 20774+/-4865) or number of patients achieving the target heart rate during stress (85 versus 86%). Hypertensive patients were significantly older (62+/-11 versus 58+/-13 years, P = 0.005) and were receiving beta-blockers more frequently (34 versus 18%, P = 0.0001). The prevalence of myocardial perfusion abnormalities was similar in patients with and without hypertension (28 versus 31% in patients with low, 38 versus 33% in patients with intermediate and 60 versus 58% in patients with high pretest probability of coronary artery disease, respectively). No significant difference was detected between the two groups regarding stress perfusion defect score (1.45+/-2.5 versus 1.50+/-2.6) or rest score (0.72+/-1.8 versus 0.68+/-1.6). Treated hypertensive patients without known coronary artery disease have a similar prevalence and severity of myocardial perfusion abnormalities at rest and at dobutamine stress compared with normotensive patients with similar clinical characteristics.

Gender differences in the relation between ST-T-wave abnormalities at baseline electrocardiogram and stress myocardial perfusion abnormalities in patients with suspected coronary artery disease

The presence of ST-T-wave abnormalities in the resting electrocardiogram was reported as a predictor of coronary artery disease (CAD) and increased morbidity and mortality. However, the independent value of ST-T abnormalities for predicting the presence and severity of perfusion abnormalities during stress testing has not been studied in a homogenous patient group without known CAD. We evaluated the relation between resting ST-T abnormalities and myocardial perfusion abnormalities in 246 patients (age 59 ± 13 years, 114 men and 132 women) without known CAD or previous myocardial infarction referred for evaluation of possible myocardial ischemia by dobutamine (up to 40 μg/kg/min) stress sestamibi or tetrofosmin single-photon emission computed tomographic imaging. Resting ST-T abnormalities were present in 123 patients, whereas 123 patients with normal resting electrocardiograms served as a matched control group. Abnormal myocardial perfusion (fixed or reversible perfusion defects) was detected in 72% of men with and in 35% of men without resting ST-T abnormalities (p <0.0001), whereas the prevalence of myocardial perfusion abnormalities was not different in women with and without resting ST-T abnormalities (27% vs 23%, p = NS). In the entire population, independent predictors of an abnormal perfusion by multivariate analysis of clinical characteristics and risk factors were male gender (p <0.001, chi-square 10.5) and resting ST-T abnormalities (p <0.05, chi-sqaure 3). Separate analysis of patients based on gender revealed resting ST-T abnormalities as independent predictors of abnormal perfusion in men (p <0.05, chi-square 4) but not in women. Stress perfusion defect score was higher in men with than without ST-T abnormalities (887 ± 545 vs 207 ± 180, p <0.001). It is concluded that resting ST-T wave abnormalities are associated with a higher prevalence and severity of resting and dobutamine-induced myocardial perfusion abnormalities in men but not in women. Resting ST-T wave abnormalities are powerful predictors of compromised myocardial perfusion independent of other clinical risk factors of CAD in men.

Myocardial perfusion, function and exercise tolerance after the arterial switch operation

Objectives. This study was conducted to determine the prevalence of myocardial perfusion abnormalities at rest and exercise and to assess exercise capacity in children after the arterial switch operation.Background. There have been sporadic reports of myocardial ischemia or sudden death in children after the arterial switch operation for transposition of the great arteries, possibly related to inadequate coronary perfusion due to kinking or stenosis of the translocated coronary arteries.Methods. Myocardial perfusion at rest and peak exercise was assessed using the scintigraphic agent technetium-99m methoxyisobutyl isonitrile (sestamibi). Exercise capacity was determined with a modified Brace protocol. Ambulatory etectrocardiographic (ECG) Holter monitoring was performed. Ventricular function, contractility and wall motion were assessed echocardiographically.Results. Twenty-three children (aged 4.2 to 7.9 years) underwent evaluation. Abnormalities were found on the rest perfusion scans in 22 children (95.6%). The left ventricular myocardium was divided into 13 segments for analysis. Of 299 rest segments, 225 (75.3%) were normal, 11 (3.7%) showed mild defects, 45 (15%) moderate defects and 18 (6%) severe defects at rest. At peak exercise, 237 segments (79.3%) were normal, 24 (8%) showed mild defects, 33 (11%) moderate defects and 5 (1.7%) severe defects. Compared with rest studies, myocardial perfusion grade at exercise was unchanged in 246 segments (82.3%), improved in 42 (14%) and worsened in 11 (3.7%). All patients had normal exercise tolerance without symptoms or ischemic ECG changes. No ventricular tachycardia was seen on Holter monitoring. All patients had a shortening fraction ≥27%. Left ventricular contractility was normal in 12 children in whom it was assessed. Regional wall motion was normal in 17 children with adequate echocardiographic images for this analysis.Conclusions. Myocardial perfusion scan abnormalities assessed by technetium-99m sestamibi are common after an arterial switch operation. These abnormalities are of uncertain clinical significance and generally lessen with exercise. The normal exercise tolerance without symptoms or ECG changes suggests that myocardial perfusion is adequate during the physiologic stress of exercise in children up to 8 years after an arterial switch operation.