Clinical significance of mild inferolateral wall ischemia of the left ventricle on 99mTc-MIBI myocardial perfusion single photon emission computed tomography (SPECT).

INTRODUCTION: Mild ischemia in the inferolateral wall on myocardial perfusion imaging is seen frequently in practice. The aim of this study is to assess the importance of the above issue on myocardial perfusion SPECT with coronary angiography. PATIENTS AND METHODS: All patients enrolled in this study exhibited mild ischemia of the inferolateral wall on myocardial single photon emission computed tomography (SPECT) with 99mTc-MIBI, using the 20 left ventricular segments model. Each patient completed a questionnaire, including type of chest pain, risk factors, and previous examinations, and all cases were followed up for one year. Luminal stenosis of >50% was classified as significant stenosis on coronary angiography. A p value < 0.05 was considered statistically significant. RESULTS: During investigation, 105 cases had mild ischemia on myocardial perfusion imaging (MPI) of which 36 subjects (22 male and 14 female) underwent coronary angiography. The mean age was 56.62±10.23 years old (age range: 36-73 years). The inferolateral wall was compared to the left circumflex (LCX) territory. Nineteen out of 36 (52.7%) cases had stenosis in the LCX. Twenty-three of 105 (21.90%) underwent revascularization during the one year follow up. In multiple logistic regressions, with LCX stenosis on angiography as the dependent variable, only abnormal MPI was independently associated significantly. CONCLUSIONS: The findings of the study may indicate that even a mild perfusion defect in the inferolateral wall should be carefully managed, especially in high-risk subjects for coronary artery disease.

Retinal vessel abnormalities predict coronary artery diseases.

BACKGROUND: There are limited data supporting an association between retinal microvascular changes and cardiovascular mortality, but there is no convincing evidence of an independent or direct association with atherosclerosis in coronary artery disease (CAD) patients. The present study examines the relationship between retinal microvascular changes and angiographic findings. METHODS: Patients who were candidates for angiography were, at first, referred to the ophthalmology department for the determination of the severity of retinal atherosclerosis based on the Scheie classification. Angiography was carried out afterwards. Each patient completed a questionnaire, also providing information on risk factors. For each patient, the Gensini score was calculated using angiography findings. RESULTS: A total of 168 patients (99 males and 69 females) with a mean age of 55.3±11.9 years were included in this study. The results show a significant association between CAD severity and retinal artery atherosclerosis (r = 0.47, p = 0.0001). In multiple regression analyses with CAD severity (using Gensini scoring) as a dependent variable, we observed a significant association between atherosclerosis scores based on Scheie criteria (ß=0.31, p<0.0001), diabetes mellitus (DM) (ß=0.29, p<0.0001), hypertension (ß=0.23, p<0.0001), smoking (ß=0.20, p<0.0001), and age (ß=0.15, p<0.0001). CONCLUSIONS: The results demonstrate that fundoscopic changes might be a predictor of CADs. However, more well-designed studies to verify these results are still needed.

The association of rate pressure product (RPP) and myocardial perfusion imaging (MPI) findings: a preliminary study.

INTRODUCTION: The product of heart rate and systolic blood pressure, termed as rate-pressure product (RPP), is a very reliable indicator of myocardial oxygen demand and is widely used clinically. There have been previous attempts to describe the relationship between RPP and the onset of pain in angina pectoris. The current study aimed to evaluate the association between RPP results and scan findings. MATERIALS AND METHODS: In total, 497 patients with suspected coronary artery disease (CAD) underwent gated, single-photon emission computed tomography (SPECT) imaging with dipyridamole, exercise, or dobutamine stress, and were included in this study. Baseline and maximum heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and electrocardiogram (ECG) results were recorded. The rate-pressure product (RPP) was calculated as the product of heart rate and systolic arterial pressure for both baseline and maximum measures. The difference between the RPP max and the basal RPP is known as the RPP reserve. Researchers also obtained semi-quantitative analyses of myocardial perfusion imaging (MPI), using gated software, demographic information, risk factors of CAD, and pretest likelihoods of CAD using nomograms. RESULT: Four hundred and ninety-seven cases, including 426 patients with dipyridamole stress, 59 with exercise stress, and 12 with dobutamine stress, underwent myocardial perfusion imaging. Scan results were positive in 194 (45.5%) and negative in 232 (54.5%) patients with dipyridamole stress. In patients with exercise stress, the scan was positive in 24 (40.7%) cases and negative in 35 (59.3%) cases. In dobutamine stressed patients, the scan was positive in 6 (50%) cases and negative in the 6 remaining cases. Dipyridamole stress resulted in a significant difference between HR at rest and at maximum (28.95 ± 24.53, p-value<0.0001), between systolic BP at rest and maximum (6.75 ± 12.50, p-value<0.0001) and between diastolic BP at rest and maximum (1.45 ± 5.80; p-value<0.0001). There was a significant correlation between sum stress scores (SSS) and reserved RPP (r= -0.12, p-value<0.001) which, in dipyridamole patients, was r=-0.18, p-value=0.0001). In addition, there was a significant association between reserved RPP and risk of CAD (p-value<0.001). In the patients with dipyridamole stress, the ejection fraction (EF) change (odds ratio =0.92; 95% CI: 0.86-0.98; p=0.01), reserve RPP (odds ratio =1.00; 95% CI: 1.00-1.00; p=0.04), risk of CAD (odds ratio =5.80; 95% CI: 3.21-10.50; p<0.0001) and age (odds ratio =0.94; 95% CI: 0.89-0.98; p=0.01) were associated significantly with MPI results, using multiple logistic regressions. CONCLUSION: The study demonstrated that RPP is associated with MPI findings using gated SPECT imaging with dipyridamole stress. However, to confirm this preliminary result, further studies are mandatory.

Myocardial perfusion imaging using technetium-99m sestamibi in asymptomatic diabetic patients.

UNLABELLED: Myocardial perfusion single-photon emission computed tomography (SPECT) has been extensively applied in the clinical assessment of patients with diabetes mellitus. The aim of the present study was to evaluate stress technetium-99m sestamibi SPECT MPI perfusion in silent myocardial ischemia and its association with some clinical and laboratory parameters in an asymptomatic diabetic population. PATIENTS, MATERIAL, METHODS: 83 subjects (age: 57.1±6.9 years) with at least five years history of type 2 diabetes, and no suspected or documented coronary artery disease (CAD) accomplished myocardial perfusion imaging; angiography was also performed in patients with abnormal MPI. RESULTS: MPI results showed that 58 patients had normal myocardial perfusion, while 25 patients showed perfusion defects (23 reversible and 2 fixed) on MPI. 12 out of the 25 (48%) with abnormal MPI findings represented abnormal angiography. We observed that pretest likelihood of CAD (odds ratio 2.32; 95%-CI: 1.05-5.13; p = 0.038) and higher HbA1c level (odds ratio 1.70; 95%-CI, 1.07-2.71; p = 0.02) were independently associated with abnormal MPI. CONCLUSION: Occult CAD was present on MPI in 1/3 patients with DM without abnormal electrocardiographic findings or evidence of peripheral arterial disease.