Biological factors and overestimation of left ventricular ejection fraction by gated SPECT.
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BACKGROUND: Some patients present an overestimated left ventricular ejection fraction (LVEF) on electrocardiogram-gated myocardial scintigraphy (gated SPECT). OBJECTIVE: To establish the relationship between biological factors and overestimated LVEF. METHODS: We selected 3838 patients who underwent gated SPECT between May 20, 2000 and September 16, 2005 with normal perfusion images and LVEF > or =50%. The following variables were analyzed: gender (29.4% females and 70.6% males), age (from 20 to 94 years - mean: 56 years), weight (from 33.5 to 150 kg - mean: 79.6 kg), height (from 138 to 220 cm - mean: 171 cm) and BMI (from 13.9 to 54 - mean: 27.2). In a subgroup of 1002 patients who underwent echocardiogram, the diastolic diameter (from 36 to 68 mm - mean 47.5 mm) and systolic diameter (from 22 to 41 mm - mean 29.8 mm) variables were included. The patients were divided into two groups: normal LVEF (< or =80%) and overestimated LVEF (>80%). The odds ratio (OR) for presenting an overestimated LVEF was calculated for each variable using logistic regression. RESULTS: The following odds ratios were found (p < 0.005): female gender OR = 3.585 (95%CI: 2.745 to 4.683), age in years OR = 1.020 (95%CI: 1.011 to 1.029) and height in cm OR = 0.893 (95%CI: 0.829 to 0.962). Weight and BMI were not significantly associated with LVEF (p>0.2). In the subgroup of 1002 patients, a statistically significant influence was found in overestimated LVEF values for the systolic diameter, gender and height variables. CONCLUSION: Although systolic diameter influences the overestimation of LVEF, the gender and height variables have an independent influence on LVEF overestimation by gated SPECT. (+info)
Echocardiographic and cardiac single photon emission computed tomography predictors of left ventricle reverse remodeling after surgical revascularization in patients with ischemic cardiomyopathy and left ventricle systolic dysfunction.
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BACKGROUND: The extent of scar or viable hypocontractile myocardial tissue determines postinfarction left ventricle remodeling. The aim of this pilot study was to evaluate the revascularization effect in a group of patients with ischemic cardiomyopathy and LV systolic dysfunction indicated for surgical revascularization, based on evidence for multivessel disease on coronarography and viable myocardium (CMR, SPECT). AIMS: To evaluate the revascularization effect in patients with ischemic LV systolic dysfunction and to find preoperative predictors of revascularization effect. METHODS: 33 patients (64+/-11 years) with baseline LVEF 34.9+/-9.3 % were included in the study. After a follow-up of 10.7+/-1.2 months, ECHO and SPECT were performed again. The whole group of patients was divided according to revascularization effect (postoperative increase LVEF > 5 % and postoperative decrease LVESV > 5 % compared with baseline) into revascularization responders (R, n = 22) and nonresponders (NR, n = 11). RESULTS: At baseline there was no difference between the subgroups in LVEF (R = 35.7+/-11.0 % vs. NR = 34.3+/-8.2 %), EDV (R = 183.6+/-43.2 vs. NR = 180.2+/-80.5 ml), ESV (R = 118.5+/-40.4 vs. NR = 119.7+/-55.2 ml). The responders showed in a revascularization effect subanalysis differences in the values of LVEF (+9.8+/-8.1 %, p < 0.009), reduction of EDV (-39.9+/-50.9 ml, p = 0.05) and ESV (-35.4+/-42.6 ml, p = 0,002) compared with baseline. The only preoperative parameters predicting LV reverse remodeling were the T(E-Em) (R = -10.6+/-44.1 vs. NR = 29.7+/-43.7 ms, p = 0.037) and the size of fixed perfusion defect (FPD) (R = 11.9+/-13.5 vs. NR = 22.9+/-15.3 % of LV, p = 0.044). CONCLUSIONS: Patients with ischemic LV systolic dysfunction with a preoperatively determined myocardial viability develop LV reverse remodeling. The only preoperative parameters predicting LV reverse remodeling were echocardiographic T(E-Em) and FPD on SPECT. (+info)
Low-dose dobutamine gated-SPECT analysis of left ventricular segmental wall thickening in ischemic cardiomyopathy.
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INTRODUCTION AND OBJECTIVES: The objective of this study was to use low-dose dobutamine (LDD) gated single-photon emission computed tomography (SPECT) to evaluate segmental thickening of the left ventricle (LV) and its relationship with changes in ejection fraction (EF) and ventricular volumes in patients with ischemic cardiomyopathy. METHODS: This prospective multicenter study involved 89 patients with ischemic cardiomyopathy (i.e., EF < or =40%) who underwent LDD gated-SPECT at rest. The LV was divided into 17 segments and systolic thickening was assessed in a total of 1513 segments during LDD infusion. RESULTS; A significant increase in LVEF (33.2% vs. 30.8%; P< .001) was observed during LDD infusion and occurred at the expense of a reduction in end-systolic volume (130.5 mL vs. 136.4 mL; P=.005). The increase in EF was > or =5% in 33.7% of patients, while the EF decreased by > or =5% in 5.6% of patients. With LDD infusion, both an improvement in > or =3 segments with severely decreased baseline thickening (odds ratio [OR] = 18.3; 95% confidence interval [CI], 5.3-63) and an improvement in > or =10 segments with mild-to-moderate alterations in baseline thickening (OR = 4.53; 95% CI, 1.26-16.16) were associated with a > or =5% increase in LVEF. CONCLUSIONS: During the assessment of global left ventricular contractile reserve by LDD gated-SPECT, attention should be paid not only to the behavior of segments with severely decreased baseline thickening, which are generally regarded as indicating viability, but also to segments with mild-to-moderate alterations and to those in which thickening decreases. (+info)
Incremental prognostic value of cardiac function assessed by ECG-gated myocardial perfusion SPECT for the prediction of future acute coronary syndrome.
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BACKGROUND: The prognostic value of ECG-gated rest 201Tl/stress 99mTc-tetrofosmin myocardial perfusion single-photon emission computed tomography for the prediction of acute coronary syndrome (ACS: myocardial infarction (MI) and unstable angina (UA)) and the implications of ejection fraction (EF) has not yet been defined in Japanese. METHODS AND RESULTS: The 1,895 patients were followed up for the occurrence ACS. The mean follow-up interval was 26.9+/-15.5 months. The 142 patients with revascularization within 60 days were censored. Summed stress score (SSS) and summed difference score (SDS) were calculated. The 19 MI and 29 UA occurred (1.1% and 1.6%, respectively). Univariate Cox analysis showed that hypertension (Wald 5.09, p<0.05), poststress EF (Wald 10.9, p<0.01), SSS (Wald 12.4, p<0.001) and SDS (Wald 18.7, p<0.001) were significant predictors of ACS. Multivariate Cox analysis showed that hypertension (Wald 4.27, p<0.05) and SDS (Wald 8.59, p<0.01) were independent predictors. When multiple clinical risk factors (number of coronary risk factors > or =2), significant ischemia (SDS > or =4) and low EF (EF <45%) were applied to multivariate Cox analysis, the combination of significant ischemia and low EF showed the highest predictive value (Wald 11.9; p<0.001) for future ACS. CONCLUSION: Poststress EF added incremental prognostic value for the prediction of ACS. (+info)
Respiratory motion detection and correction in ECG-gated SPECT: a new approach.
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Single photon emission computed tomography: an alternative imaging modality in left ventricular evaluation.
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Various diagnostic imaging modalities have been used for quantitative left ventricular (LV) parameters. Because of the suboptimal value of the most widely used technology, two-dimensional (2D) echocardiography, 3D ultrasonographic imaging has improved accuracy for LV volume and function. Single photon emission computed tomography (SPECT) is another diagnostic method where LV volumetric and functional parameters can be accurately provided by gated myocardial perfusion tomographic slices. First pass radionuclide venticulography is another imaging modality which has some practical limitations. Despite lower ejection fraction (EF) values compared with invasive approach, noninvasive techniques are accurate in determination of normal and depressed EF. Noninvasive techniques with 3D approach including gated SPECT are beneficial for not only global but also regional LV evaluation. It has been mentioned that the slight difference between echocardiography and SPECT could be caused by the diverse population studied. The results of diagnostic stress tests support that SPECT is feasible to use in evaluation of LV volume and functional analysis. Magnetic resonance imaging is an expensive modality to use routinely, but it preserves its importance in selected patients for providing precise LV geometric data. (+info)