Long-term prognostic value of early poststress (99m)Tc-tetrofosmin lung uptake during exercise (SPECT) myocardial perfusion imaging.
OBJECTIVE
The aim of this study was to determine the long-term prognostic value of early poststress lung/heart ratio (LHR) of (99m)Tc-tetrofosmin radioactivity.


METHODS
We studied 276 patients (aged 62.2 + or - 8.9 years, 168 men) with stress/rest (99m)Tc-tetrofosmin myocardial gated-SPECT and coronary angiography. To evaluate myocardial ischaemia, we calculated the summed stress score, summed rest score and summed difference score indices. For the eLHR calculation, an anterior image was acquired, 4-6 min after radiotracer injection at stress (eLHR was defined as mean counts per pixel in the lung region of interest divided by the mean counts per pixel in the myocardial region of interest). Cardiovascular death and nonfatal myocardial infarction were considered as hard cardiac events, and late revascularization procedures as soft cardiac events. The Cox proportional hazards model in a stepwise method was used to determine the independent predictors for hard and soft cardiac events.


RESULTS
During the follow-up period hard cardiac events occurred in 28 patients (10.1%) and soft cardiac events in 32 patients (11.6%). Implying multiple Cox regression analysis, eLHR was found to be a significant independent predictor for both soft and hard cardiac events. The hazard ratio (for a 0.1 unit increase) was 4.41 (95% CI 1.52-12.73, p=0.006) for soft cardiac events and 4.22 (95% CI 2.07-8.62, p<0.001) for hard cardiac events. The other significant prognostic factors were use of beta-blockers, the summed stress score and the use of nitrates for soft events, and exercise duration and the summed stress score for hard cardiac events.


CONCLUSIONS
Early poststress (99m)Tc-tetrofosmin LHR has an independent and powerful value in predicting hard and soft cardiac events.
Georgoulias
Panagiotis
P
Department of Nuclear Medicine, University Hospital of Larissa, Mezourlo, Larissa, 41110, Greece. pgeorgoul@med.uth.gr
Tsougos
Ioannis
I
Valotassiou
Varvara
V
Tzavara
Chara
C
Xaplanteris
Petros
P
Demakopoulos
Nikolaos
N
D000368:Aged; D006328:Cardiac Catheterization; D055426:Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography; D002318:Cardiovascular Diseases / Q000401:mortality*; D015897:Comorbidity; D017023:Coronary Angiography; D003327:Coronary Disease / Q000000981:diagnostic imaging; D015444:Exercise; D005080:Exercise Test; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008168:Lung / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology* / Q000628:therapy; D055414:Myocardial Perfusion Imaging; D009204:Myocardial Revascularization / Q000706:statistics & numerical data; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D011379:Prognosis; D016016:Proportional Hazards Models; D019275:Radiopharmaceuticals; D016037:Single-Blind Method; D012907:Smoking / Q000453:epidemiology
D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C078700:technetium tc-99m tetrofosmin