Myocardial perfusion images (SPECT Tc99m SESTAMIBI) in heart failure patients and their association with ventricular arrhythmias profile

S8

M O N D M A O Y N D M A A Y Y M 9 A Y 9

Abstracts Monday, May 9, 2005

Journal of Nuclear Cardiology March/April 2005

1.29

1.31

Is there a relationship between myocardial perfusion scintigraphy and carotid ultrasound findings in predictive model for coronary artery bypass patients? I. Irena Peovska1, M. Bosevski2, J. Maksimovic Pavlovic3, M. Vavlukis.3 1Institute for Heart Disease, Nuclear Imaging, Skopje, Macedonia, The Former Yugoslav Republic of, 2Insitute for Cardiovascular diseases, Periferal vascular diseases department, Skopje, Macedonia, The Former Yugoslav Republic of, 3Institute for heart disease, Nuclear Cardiology Laboratory, Clinical Center Skopje, Macedonia, The Former Yugoslav Republic of

Myocardial perfusion images ( SPECT Tc99m SESTAMIBI) in heart failure patients and their association with ventricular arrhythmias profile. A. Arturo Orea1, E. Asensio2, L. Castillo3, J. Dorantes2, R. Narva´ez2, O. Gonza´lez.4 1 Instituto Nacional de Ciencias Medicas, Heart Failure Clin and Nuclear Cardiol, Mexico City, Mexico, 2Inst. Nal. de la Nutricion “S.Zubiran”, Cardiology Dept., Mexico City, Mexico, 3Inst. Nal. Ciencias Med. y Nut. SZ, Heart Failure Clinic, Mexico City, Mexico, 4Inst. Nal. de Ciencias Med y N. “SZ”, Cardiologia y Medicina Nuclear, Mexico City, Mexico

Aims: The aim of the study was to correlate myocardial perfusion imaging (MPI) and common carotid artery intimal-medial thickness (CCA IMT) findings in patients (pts) referred for coronary artery by-pass surgery (CABG) and to evaluate those factors in predictive model for these pts. Materials and methods: 58 pts (with age 61,7⫾8,1 years) with angiographycaly established CAD and referred for CABG were evaluated for the following parameters: age, sex, cholesterol, systolic blood pressure, NYHA classification, history of myocardial infarction, stroke, diabetes, peripheral arterial disease and previous revascularization. All pts underwent one day rest/nitrate enhanced Gated SPECT MPI, with evaluation of LVEF at rest and after nitrate application. 17-segment analysis with 5 point scoring system (0⫽normal; 4⫽no uptake) with calculation of semiquantitative summed nitrate score (SNS) and summed rest score (SRS) was performed. Viability index was determined in all pts. CCA IMT was measured by B-mode ultrasound and presented as mean value of two measurements from both sides. Carotid stenosis (CS) ⬎60% was considered significant. Pts were followed for cardiovascular events 12 months after the CABG. Results: We obtained mean values of LVEF 46.2⫾14.4%, VI 0.76 ⫾0.15, SRS 17.76⫾13.81 and SNS 12.89⫾10.36. Abnormal perfusion was found in 55 pts (94,83%). Carotid ultrasound detected CCA IMT 0,90⫾0,24 mm, with increased value (⬎/⫽0,8mm) in 39 pts (66%). 16 pts (27,1%) had significant CS. Multiple regression model was built to define relationships. Strong correlation was found between VI and increased CCA IMT (b 0.37, p 0.001) and with CS (b 0.51,p 0.001). SNS was associated with increased CCA IMT (b 0.02, p 0.001) and with CS (b 0.23, p 0.001).We registered 9 cardiovascular events in 8 pts and 5,2% rate of mortality. Cox proportional model presented VI as an independently factor of events (OR 3.65,CI 3.03-4.12,p 0.05). LVEF (OR 3.48, CI 2.97-3.86,p 0.04) and age (OR 4.05,CI 3.34-4.82,p 0.04) were predictors of mortality. This analysis showed 1.21 increase in VI risk ratio for events and 1.17 increase in LVEF risk for death, when pts were stratified for increased CCA IMT. Only univariate analysis presented associations of CCA IMT and CS together with mortality (OR 2.31,CI 1.92-2.63, p 0.05). Conclusion: Myocardial perfusion viability index and LVEF are independently factors for prognosis of patients referred for CABG, according this study model. Carotid ultrasound has an additional clinical usefulness in risk assessment approach of these patients.

Background: Several tools allow establishing mortality risk in heart failure (HF) patients, among them the presence of ventricular arrhythmia detected by holter monitoring. We have previously found that optimal medical treatment was associated to an increase in ventricular arrhythmia frequency in our population during a one-year follow-up period. We hypothesized that such a modification in the arrhythmic profile could depend on the rescue of electrically unstable hibernating myocardium detected by myocardial perfusion images (MPI) techniques. METHODS: On inclusion in a HF clinic, we performed a basal 24-Hr holter, a perfusion scintigraphy and other tests. When we reached optimal medication dosages or a stable functional class, another holter and scintigraphy were made. We analyzed the number and sort of arrhythmic events, as well as heart rate variability and the number of myocardial territories affected in the perfusion scan at both times. RESULTS: We have 14 patients with both studies performed in the past year. Nine are men, mean age 60.2⫾ 13.9 years. All of them had ischemic heart disease. Three patients were in NYHA functional class (FC) III at enrollment, 3 in FC II and 8 in FC I. At follow-up, 10 were in FC I and 4 in FC II. Among patients with SDNN⬎100 and LVEF⬎40%, premature ventricular contractions went from 268.8⫾416 at enrollment to 1821⫾2824 during follow-up (p⫽0.008). The mean number of severely ischemic segments in the anterior descending artery territory went from 2⫾2.6 to 0.8⫾1,2 (p⫽0.01).CONCLUSIONS: Our findings suggests that optimal medical treatment recovers hibernating myocardium that can be electrically unstable at the onset of recovery. A longer follow-up is mandatory in order to evaluate the behavior of the arrhythmic profile among more stable myocardial tissue detected by MPI techniques.

1.30

1.32

Usefulness of Fourier phase analysis of equilibrium radionuclide angiography for distinguishing ischaemic from nonischaemic cardiomyopathy. E. Enrique Vallejo, G. Rodriguez, L. Jimenez, S. Hernandez, D. Bialostozky. Instituto Nacional de Cardiologia, Nuclear Cardiology, Mexico City, D.F., Mexico

NT-proBNP in symptom limited exercise myocardial perfusion scintigraphy: sustained elevation after exercise and independent association with myocardial ischemia extent. PM. Marc Van der Zee1, HJ. Verberne2, JP. Van Straalen3, JC. Fischer3, GTB. Sanders3, BLF. Van Eck-Smit2, RJ. De Winter.1 1Academic Medical Center, cardiology, Amsterdam, Netherlands, 2Academic Medical Center, Nuclear Medicine, Amsterdam, Netherlands, 3Academic Medical Center, Clinical Chemistry, Amsterdam, Netherlands

Background: left ventricular (LV) systolic function analyzed by equilibrium radionuclide angiography (ERNA), has previously failed to differentiate ischaemic cardiomyopathy (ICM) from nonischaemic cardiomyopathy (nICM). Fourier phase analysis of ERNA (FPA-ERNA) allows evaluation of ventricular contraction in space and time. This study evaluates whether FPA-ERNA can accurately distinguish between patients with ICM from those with nICM. Methods: a total of 82 patients with LV dysfunction were included (mean LVEF 0.29⫾0.11). FPA-ERNA was generated using an automatic program. The program assigns a phase angle to each pixel of the phase image, derived from the first Fourier harmonic of time. Mean phase angle (MPA), standard deviation of the MPA (intraventricular contractile synchrony, sdMPA), and mode of phase angle (mPA) were measured for the right ventricular (RV) and LV blood pools. All values are given as a mean ⫾ SD. Comparisons between groups were made using the Student t test. Multivariate analysis was used to identify variables that could discriminate between patients with nICM and patients with ICM. Results: twenty-five patients had nICM and 57 had ICM. Mean LVEF was 0.24⫾0.10 for patients with nICM and 0.31⫾0.09 for patients with ICM and (p⫽0.05). Compared to patients with ICM, patients with nICM had an increased delay (“left shift of phase angle”) of LV-MPA and LV-mPA (167⫾29° vs 152⫾23°, p⫽0.03; and 159⫾28° vs 144⫾24°, p⫽0.02, respectively). sdMPA of LV and RV, RV-MPA, and RV-mPA were no different between nICM and ICM patients. Multivariate analysis identified the LV-mPA as the only independent predictor of nonischaemic versus ischaemic etiology of cardiomyopathy (OR 0.36, 95% CI 0.06 to 0.65, p⫽0.017). Conclusions: our study shows that Fourier phase analysis of equilibrium radionuclide angiography is a useful method to distinguish LV dysfunction related to nICM or ICM on the basis of identifying the patterns of ventricular contraction in space and time.

Aim: in patients with overt heart failure, levels of N-terminal pro-BNP (NT-proBNP) are associated with ventricular dysfunction. Increased levels are also found in acute coronary syndromes, suggesting that other mechanisms such as myocardial ischemia may also cause elevations of NT-proBNP. We determined the levels of NT-proBNP before and after symptom limited exercise, as well as their association with myocardial perfusion scintigraphy outcome. Methods: 38 patients were included undergoing symptom limited exercise myocardial perfusion scintigraphy according to a two-day stress/rest protocol using 99m Technetium Tetrofosmin and ECG gated single photon emission tomography. Stress and rest perfusion images were scored using a 5-point semi-quantitative score for each of 17 myocardial segments, classifying each segment as normal (0), equivocal abnormal (1), mildly abnormal (2), moderately abnormal (3) or severely abnormal (4). The summed difference score (SDS) was calculated as the difference between summed stress score and summed rest score. A SDS of three or greater was arbitrarily considered to indicate clinically relevant ischemia. Left ventricular ejection fraction (LVEF) was calculated using a completely automated algorithm. Blood samples were drawn at baseline, at maximum exercise (at least 85% of the age predicted heartrate), and at 1, 2, 3, 4, and 6 hours after maximum exercise, for assessment of levels of NT-proBNP and creatinine (baseline only). For analysis, NTproBNP levels were logtransformed to a normal distribution. Results: 15 patients were classified as having myocardial ischemia. Baseline NTproBNP levels were 75 pg/mL (33-236) (median, IQ range), and were increased at maximum exercise (137% of baseline (99-176)) (p⬍0.001), with a second peak 4 hours later (137% (118-173)) (p⬍0.001). In a multivariate analysis, NT-proBNP levels were independently associated with creatinine clearance (Cockroft and Gault), LVEF, and SDS, as assessed from the samples at baseline (adjusted R2 of model ⫽ 0.537), maximum exercise (adj.R2 ⫽ 0.561), and 4 hours later (adj.R2 ⫽,0.476). Conclusions: baseline levels of NT-proBNP, as well as the sustained elevations after symptom limited exercise testing are independently associated with extent of inducible myocardial ischemia, LVEF and creatinine clearance.