title: Impact of revascularization and myocardial viability determined by nitrate-enhanced Tc-99m sestamibi and Tl-201 imaging on mortality and functional outcome in ischemic cardiomyopathy.
abstract: BACKGROUND
  Nitrate-enhanced perfusion imaging has been shown to detect viability in dysfunctional myocardium, but nitrate-enhanced technetium 99m sestamibi has not been compared with nitrate-enhanced thallium 201.
  
  
  RESULTS
  Fifty-six patients with ischemic cardiomyopathy and heart failure (New York Heart Association classes II-IV) were scheduled for revascularization. Through use of a matching 12-segment model, nitrate-enhanced Tl-201 and Tc-99m sestamibi uptake at rest was assessed by 2 sets of blinded investigators. All single photon emission computed tomography data sets were read separately. Additional exercise Tc-99m sestamibi single photon emission computed tomography was performed on a separate day. Myocardial viability was thought to be present when the tracer uptake score was less than 3 (normal, 0; absent, 4). Of the 56 patients scheduled to undergo revascularization, only 23 (41%) underwent the procedure and the remainder continued medical therapy. Functional assessment by rest echocardiography was performed at 21 +/- 8 months, and survival was determined at 40 +/- 18 months. The baseline clinical and hemodynamic parameters were similar in the revascularization (n = 23) and medical therapy (n = 33) groups. Perfusion scores with nitrate-enhanced Tl-201 and Tc-99m sestamibi were similar in dysfunctional segments. Stress Tc-99m sestamibi reversible defects predicted significant improvement in left ventricular function compared with those without defects (P <.01) after revascularization. Cox regression model showed that when at least 5 reversible segments were viable, revascularization produced greater improvements in New York Heart Association class, a better trend toward survival (P =.07 for Tl-201 and P =.06 for Tc-99m), and a significantly greater impact on reverse remodeling.
  
  
  CONCLUSIONS
  Myocardial viability determined by nitrate-enhanced Tl-201 and myocardial viability determined by Tc-99m sestamibi are equivalent for predicting functional improvements, remodeling, and survival after revascularization in patients with ischemic cardiomyopathy.
mesh_terms: D000368:Aged; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006321:Heart / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology*; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000209:etiology / Q000401:mortality / Q000601:surgery; D006801:Humans; D008297:Male; D017202:Myocardial Ischemia / Q000150:complications / Q000000981:diagnostic imaging* / Q000401:mortality* / Q000601:surgery; D009204:Myocardial Revascularization / Q000401:mortality; D005996:Nitroglycerin / Q000494:pharmacology; D019275:Radiopharmaceuticals; D012720:Severity of Illness Index; D016037:Single-Blind Method; D015996:Survival Rate; D017256:Technetium Tc 99m Sestamibi; D013793:Thallium; D015899:Tomography, Emission-Computed, Single-Photon; D016896:Treatment Outcome
chemical_list: D019275:Radiopharmaceuticals; C027549:thallium chloride; D017256:Technetium Tc 99m Sestamibi; D013793:Thallium; D005996:Nitroglycerin