Long-term prognostic value of 13N-ammonia myocardial perfusion positron emission tomography added value of coronary flow reserve.
OBJECTIVE
The goal of this study was to assess the predictive value of myocardial perfusion imaging with (13)N-ammonia positron emission tomography (PET) and coronary flow reserve (CFR) on long-term prognosis in patients with suspected myocardial ischemia.


BACKGROUND
No prognostic data exist on the predictive value of CFR and (13)N-ammonia PET.


METHODS
Perfusion and CFR were assessed in 256 patients using (13)N-ammonia PET, and follow-up was obtained in 245 (96%) patients. Sixteen early revascularized patients were excluded and 229 were assigned to normal versus abnormal perfusion or normal versus abnormal CFR (<2.0). Major adverse cardiac events (MACE) (cardiac death, nonfatal myocardial infarction, late revascularization, or hospitalization for cardiac reasons) were assessed using the Kaplan-Meier method. Cox proportional hazard regression was used to identify independent predictors for cardiac events.


RESULTS
During follow-up (5.4 +/- 2.2 years), 78 patients had at least 1 cardiac event, including 29 cardiac deaths. Abnormal perfusion (n = 126) was associated with a higher incidence of MACE (p < 0.001) and cardiac death (p < 0.05). In patients with normal perfusion, abnormal CFR was independently associated with a higher annual event rate over 3 years compared with normal CFR for MACE (1.4% vs. 6.3%; p < 0.05) and cardiac death (0.5% vs. 3.1%; p < 0.05). In abnormal perfusion, CFR remained predictive throughout the 10-year follow-up (p < 0.001).


CONCLUSIONS
Perfusion findings in (13)N-ammonia PET and CFR are strong outcome predictors. CFR allows further risk stratification, suggesting a "warranty" period of 3 years if normal CFR is associated with normal perfusion. Conversely, in patients with abnormal perfusion, an impaired CFR has added value for predicting adverse outcomes.
Herzog
Bernhard A
BA
Cardiac Imaging Section, University Hospital Zurich, Ramistrasse 100, Zurich, Switzerland.
Husmann
Lars
L
Valenta
Ines
I
Gaemperli
Oliver
O
Siegrist
Patrick T
PT
Tay
Fabian M
FM
Burkhard
Nina
N
Wyss
Christophe A
CA
Kaufmann
Philipp A
PA
D000641:Ammonia / Q000493:pharmacokinetics; D003326:Coronary Circulation / Q000502:physiology*; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000503:physiopathology; D009206:Myocardium / Q000378:metabolism*; D049268:Positron-Emission Tomography / Q000379:methods*; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011868:Radioisotopes; D012189:Retrospective Studies; D015996:Survival Rate; D013557:Switzerland / Q000453:epidemiology; D013997:Time Factors
D011868:Radioisotopes; D000641:Ammonia