title: Quantification of myocardial area at risk in the absence of collateral flow: the validation of angiographic scores by myocardial perfusion single-photon emission computed tomography.
abstract: OBJECTIVE
  Our study aimed to compare the area at risk (AAR) determined by single-photon emission computed tomography (SPECT) with the Bypass Angioplasty Revascularization Investigation (BARI) and modified Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH) angiographic scores in the setting of patients undergoing coronary angioplasty for either unstable angina or an STEMI.
  
  
  BACKGROUND
  Radionuclide myocardial perfusion imaging prior to reperfusion has classically been the most widely practised technique for assessing the AAR and has been successfully used to compare the efficacy of various reperfusion strategies in patients with an ST-segment elevation myocardial infarction (STEMI). The BARI and modified APPROACH scores are angiographic methods widely used to provide a rapid estimation of the AAR; however, they have not been directly validated with myocardial perfusion single-photon emission computed tomography (SPECT).
  
  
  METHODS
  Fifty-five patients with no previous myocardial infarction who underwent coronary angioplasty for single-vessel disease (unstable angina: n = 25 or an STEMI: n = 30) with no evidence of collaterals (Rentrop Collateral Score <2) were included in a prospective study. In STEMI patients, the (99m)Tc-tetrofosmin was injected prior to opening of the occluded vessel and, in patients with unstable angina after 10-15 seconds of balloon inflation. Acquisition was performed with a dual-head gammacamera with a low-energy and high-resolution collimator. A total of 60 projections were acquired using a non-circular orbit. No attenuation or scatter correction was used. Maximal contours of hypoperfusion regions corresponding to each coronary artery occlusion were delineated over a polar map of 17 segments and compared with the estimated AAR determined by two experienced interventional cardiologists using both angiographic scores.
  
  
  RESULTS
  Mean AAR percentage in SPECT was 35.0 (10.0%-56.0%). A high correlation was found between BARI and APPROACH scores (r = 0.9, P < .001). Furthermore, a high correlation was also observed between BARI versus SPECT and APPROACH versus SPECT to estimate the AAR (r = 0.9, P < .001 and r = 0.8, P < .001, respectively). Better correlations were observed when the left anterior descending artery (LAD) was revascularized (r = 0.8, P < 0.001 with BARI; r = 0.8, P = .001 with APPROACH) compared to other territories (r = 0.8, P = .001 with BARI; r = 0.7, P = .001 with APPROACH). Also, better correlations were observed in patients who underwent an elective rather than a primary percutaneous revascularization procedure.
  
  
  CONCLUSIONS
  In the absence of collateral flow, BARI and APPROACH scores constitute valid methods for AAR estimation in current clinical practice, with more accurate results when used for the LAD territory; both are useful not only in STEMI patients but also in patients with unstable angina.
authors.affiliation: Department of Cardiology, Hospital Universitari Vall d'Hebron, Paseo Vall d'Hebron 119-129, 08035 Barcelona, Spain. jfrodriguezpalomares@gmail.com
authors.forename: José F
authors.initials: JF
authors.lastname: Rodríguez-Palomares
authors.forename: Albert
authors.initials: A
authors.lastname: Alonso
authors.forename: Gerard
authors.initials: G
authors.lastname: Martí
authors.forename: Santiago
authors.initials: S
authors.lastname: Aguadé-Bruix
authors.forename: M T
authors.initials: MT
authors.lastname: González-Alujas
authors.forename: Guillermo
authors.initials: G
authors.lastname: Romero-Farina
authors.forename: Jaume
authors.initials: J
authors.lastname: Candell-Riera
authors.forename: Bruno
authors.initials: B
authors.lastname: García del Blanco
authors.forename: Artur
authors.initials: A
authors.lastname: Evangelista
authors.forename: David
authors.initials: D
authors.lastname: García-Dorado
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D017023:Coronary Angiography / Q000379:methods; D003326:Coronary Circulation; D004562:Electrocardiography; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000473:pathology; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D009206:Myocardium / Q000473:pathology*; D010477:Perfusion; D015203:Reproducibility of Results; D012306:Risk; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*