title: Transthoracic measurement of left coronary artery flow reserve improves the diagnostic value of routine dipyridamole-atropine stress echocardiogram.
abstract: BACKGROUND
  We hypothesized that coronary flow reserve (CFR) in the left anterior descending artery (LAD) can be effectively measured during an accelerated dipyridamole-atropine stress echocardiography (DASE) protocol to improve the diagnostic performance of the test.
  
  
  METHODS
  In 64 patients with suspected or known coronary artery disease scheduled for coronary angiography DASE with concomitant CFR measurement in LAD was performed.
  
  
  RESULTS
  Coronary flow reserve measurement and calculation were feasible in 83% of patients. The positive predictive value of undetectable LAD flow was 81% for severe LAD disease. Measured values of CFR were in the range 1.3-4.1 (mean: 2.2 ±0.7). Significantly lower CFR was found in patients with LAD disease (1.97 ±0.62 vs. 2.55 ±0.57, p = 0.0015). The optimal cutoff for detecting ≥ 50% stenosis was CFR ≤ 2.1 (ROC AUC 0.776), corresponding with 68% sensitivity and 84% specificity. In patients with negative DASE results 67% of patients with LAD disease had abnormal CFR, whereas in patients with a positive DASE result 92% of patients with normal LAD had normal CFR. The DASE diagnostic accuracy for the detection of coronary artery disease (CAD) increased from 75% to 85% when CFR measurement was added to wall motion abnormality (WMA) analysis. No test with both abnormalities was false positive for the detection of coronary disease.
  
  
  CONCLUSIONS
  Incorporation of CFR measurement into WMA-based stress echocardiography is feasible even in an accelerated DASE protocol and can be translated into an approximate gain of 10% in overall test accuracy.
authors.affiliation: Department of Cardiology, Medical University of Lodz, Poland.
authors.forename: Jarosław D
authors.initials: JD
authors.lastname: Kasprzak
authors.forename: Paulina
authors.initials: P
authors.lastname: Wejner-Mik
authors.forename: Aria
authors.initials: A
authors.lastname: Nouri
authors.forename: Ewa
authors.initials: E
authors.lastname: Szymczyk
authors.forename: Maria
authors.initials: M
authors.lastname: Krzemińska-Pakuła
authors.forename: Piotr
authors.initials: P
authors.lastname: Lipiec
keywords: cardiac ultrasound; coronary circulation; stress echocardiography