Populations presenting for a myocardial perfusion imaging study: Results from an international study of utilization and outcomes following pharmacologic stress spect imaging

S28

Abstracts Saturday, October 2, 2004

Journal of Nuclear Cardiology July/August 2004

Objective: To investigate the current uses, outcomes, safety, and prognostic value of PS SMPI in a heterogeneous, international, population of patients who present for PS-SMPI Methods: Between 5/03–12/03, 89 private, community and academic clinical sites in 8 countries registered all patients who presented for any SMPI study over 20 consecutive working days. Patients referred for PS or low-level exercise (LE) PS were eligible. Investigators recorded the ACC / AHA Pretest Likelihood for CAD, antianginal usage, the PS agent and adverse events, and the isotope/imaging protocol. SPECT images were analyzed at each site; investigators assigned stress and rest scores using a 17-segment (0 – 4 perfusion scale) model. Patients are followed for 1-yr for clinical outcomes, through 12/04. Results: 16,653 patients were referred for a SMPI and logged at screening: 9,075 (55%) for an exercise study and 7,578 (45%) for a PS (⫹LEPS) study (Table 1). 5,174 patients were enrolled for the 1-year follow-up phase for outcomes; 943 (18%) of the enrolled PS patients had an LEPS study. Conclusions: This study, the largest international prospective registry of SMPI utilization, shows that adenosine is rarely used outside the US and UK. The design provides opportunity to study the characteristics of patients referred for PS-SMPI, provides an up to date PS safety registry, and allows assessment of the prognostic value of PS-SMPI across many co-variables. This study will allow for extensive model development, and validation, to assess the uses and prognostic value of PS-SMPI. Table 1. Enrollment. Enrollment (# Sites, n) and PS Agent Use (n, %) by Country PS Agent (n ⫽ 5174) Adenosine (n ⫽ 2884, 56%) Dipyridamole (n ⫽ 2031, 39%) Dobutamine (n ⫽ 259, 5%)

USA UK CAN ARG BRA CHI BEL ITA 72 2 5 4 1 2 1 2 n ⫽ 3477 n ⫽ 24 n ⫽ 64 n ⫽ 17 n ⫽ 35 n ⫽ 67 n ⫽ 38 n ⫽ 17 8 2 3 2 2616 241 4 3 11 0 0 9 76%

97%

⬍1%

2%

636 18% 225

0

624 97% 14 3%

169 98% 1 2%

7 6%

3%

5%

331 67 38 166 94% 100% 100% 94% 10 0 0 2 ⬍1% 3% ⬍1%

65.25 POPULATIONS PRESENTING FOR A MYOCARDIAL PERFUSION IMAGING STUDY: RESULTS FROM AN INTERNATIONAL STUDY OF UTILIZATION AND OUTCOMES FOLLOWING PHARMACOLOGIC STRESS SPECT IMAGING R Hachamovitch, RJ Barrett, H Haught, CS Lim, R Underwood, SA Jenkins, JR Johnson, and JE Udelson for the Investigators USC Medical Center, Los Angeles, CA; King Pharmaceuticals R&D, Cary, NC; Heart Center, Huntsville, AL; Ashville Cardiology, Ashville, NC; Royal Brompton Hospital, London, UK; and Tufts-NE Medical Center, Boston, MA Objective: To characterize the heterogeneous populations of patients presenting for SPECT MPI (SMPI). Methods: All patients presenting for SMPI from 89 private practices and academic hospitals in 8 countries were logged over a 20-consecutive working day period from 3/0312/03. Demographics, stressor [exercise, pharmacologic stress (PS) or low-level exercise ⫹ PS (LEPS)] and PS agent were recorded for each patient. Patients who were referred for PS or LEPS were eligible for enrollment, scoring of their SMPI study, and follow-up for outcomes over a 1-yr period. Results: 16,653 patients were screened, with 54% and 46% referred for exercise and PS-SMPI, respectively. 5174 (68% of screened PS patients) patients were enrolled, characterized, and are currently being followed for outcomes (Table 1). Statistical models are being developed to fully characterize PS-SMPI patient populations, relationships to clinical outcomes, and SMPI results. Conclusions: Population distributions vary by gender, age, race, practice type, and ACC / AHA Pretest Likelihood for CAD for screened and enrolled patients. Females were referred for PS at higher rates (⬎50%) than males. The age distribution increases with each likelihood cohort.

Table 1. Population Demographics

Screened: Exercise: PS: Enrolled: PS ⫹ LEPS: PS Agent: Adenosine: Dipyridamole: Dobutamine: ACC/AHA Pretest Likelihood for CAD: Very Low: Low: Intermediate: High: Known CAD:

N

Gender (% Female)

Age (SD)

Race (% Caucasian)

9075 7578

39% 52%

58.6 (12.08) 66.2 (12.34)

78% 80%

5174

52%

66.3 (11.87)

83%

2884 2031 259

52% 50% 64%

65.7 (12.13) 65.8 (11.48) 65.5 (11.60)

84% 81% 83%

157 1001 1335 384 2142

75% 57% 63% 48% 41%

51.1 (12.70) 64.9 (12.82) 65.5 (11.76) 68.8 (10.56) 68.2 (10.58)

79% 81% 81% 80% 86%

65.26 T-WAVE INVERSION IN Q WAVE MYOCARDIAL INFARCTION DOES NOT PREDICT MYOCARDIAL VIABILITY ON RB-82/18-FDG P.E.T. IMAGING J Rosman, S Hanon, M Shapiro, P Schweitzer, A VanTosh Beth Israel Medical Center, University Hospital and Manhattan Campus for the Albert Einstein College of Medicine. New York, New York Background: The12-lead ECG has been used as a clinical predictor of myocardial viability. Q-waves on ECG suggest irreversible scarring, but are relatively inaccurate descriptors. T-wave inversion in an area of Q-wave infarction (QWMI) has been advocated as a parameter identifying viable myocardium, but its accuracy is not defined. We thus correlated the presence of T-wave inversion in QWMI with the results of PET imaging to define its value as an ECG predictor of viability. Methods: We evaluated 25 patients with QWMI on ECG who had Rb-82 PET perfusion and 18-FDG metabolic imaging (PET) for viability. Patients with QRS duration ⬎110 msec, or acute ST elevation were excluded. ECGs were interpreted as follows: Pathologic Q-waves were defined using standard criteria. Q-waves and T-wave inversion were ascribed to the anterior, inferior, and lateral myocardial regions using Novacode system. For each myocardial region having Q-waves, a Novacode T-wave score (T) was calculated (10 points for each mm T-wave inversion in the lead with greatest T-wave depth). PET images were scored using a 21 segment, five-grade system. Regions were considered viable if the majority of segments had tracer uptake graded 0 –3. We tested the hypothesis that increasing T in areas of QWMI could predict viable myocardium. Results: Twenty-five patients had 35 myocardial regions with Q-waves. Of 35 regions, 19 (54%) were viable. T ⫽ 0 (no T-inversion) was present in 8/19 regions with viability (42%), vs. 11/16 regions with no viability (specificity 69%, NPV 58%). T ⱖ 10 (T-inversion present) was present in 11/19 regions with viability, but was also present in 5/16 (31%) without viability (sensitivity 58%, PPV 69%). Of 9 regions with T ⱖ 20, 7 were viable (sensitivity 37%, PPV 78%). There were no significant differences in sensitivity, specificity, or predictive value for varying T in identifying myocardial viability. Conclusions: T is neither a sensitive nor a specific predictor of viability in myocardial regions with QWMI. Thus, clinical decision-making involving issues of viability should not be based on ECG criteria, but should include scintigraphic perfusion and metabolic imaging. 65.27 UNDEREPORTING OF ABNORMAL EXTRACARDIAC UPTAKE ON TC-99-MIBI MYOCARDIAL PERFUSION SCAN K Aziz1, S Jones2, T Yasuda1,2, H Gewirtz1, JA Scott2 Division of Nuclear Cardiology, Departments of Cardiology1and Radiology2, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts Background: Tc-99m-Sestamibi (MIBI) is known to accumulate in tumor and inflammatory lesions. Abnormal extracardiac MIBI uptake has been reported in 1.7% cases (J Nucl Cardiol 2003;10:395– 402). This study tests