Background-Coronary arteries without focal stenosis at angiography are generally considered non-flow-limiting.However, atherosclerosis is a diffuse process that often remains invisible at angiography. Accordingly, we hypothesized that in patients with coronary artery disease, nonstenotic coronary arteries induce a decrease in pressure along their length due to diffuse coronary atherosclerosis. Methods and Results-Coronary pressure and fractional flow reserve (FFR), as indices of coronary conductance, were obtained from 37 arteries in 10 individuals without atherosclerosis (group I) and from 106 nonstenotic arteries in 62 patients with arteriographic stenoses in another coronary artery (group II). In group I, the pressure gradient between aorta and distal coronary artery was minimal at rest (1Ϯ1 mm Hg) and during maximal hyperemia (3Ϯ3 mm Hg). Corresponding values were significantly larger in group II (5Ϯ4 mm Hg and 10Ϯ8 mm Hg, respectively; both PϽ0.001). The FFR was near unity (0.97Ϯ0.02; range, 0.92 to 1) in group I, indicating no resistance to flow in truly normal coronary arteries, but it was significantly lower (0.89Ϯ0.08; range, 0.69 to 1) in group II, indicating a higher resistance to flow. In 57% of arteries in group II, FFR was lower than the lowest value in group I. In 8% of arteries in group II, FFR was Ͻ0.75, the threshold for inducible ischemia. Conclusion-Diffuse coronary atherosclerosis without focal stenosis at angiography causes a graded, continuous pressure fall along arterial length. This resistance to flow contributes to myocardial ischemia and has consequences for decision-making during percutaneous coronary interventions.

Background-Inducing both maximal and steady-state coronary hyperemia is of clinical importance to take full advantage of fractional flow reserve measurements. The present study compares different dosages and routes of administration of adenosine 5Ј-triphosphate (ATP), adenosine, contrast medium, and papaverine regarding their potential to achieve both maximal and steady-state hyperemia. Methods and Results-In 21 patients with an isolated coronary stenosis, coronary vasodilation was induced successively by papaverine (20 mg intracoronary), adenosine (20 and 40 g intracoronary), ATP (20 and 40 g intracoronary), iohexol (6 mL intracoronary), adenosine or ATP through an antecubital vein (140 and 180 g · kg Ϫ1 · min

The present data indicate (1) that the 0.75 cutoff value of FFR to distinguish patients with positive from patients with negative SPECT imaging is valid after a myocardial infarction and (2) that for a similar degree of stenosis, the value of FFR depends on the mass of viable myocardium.

Exercise testing is recommended as a first-line diagnostic test in patients with suspected SAP, 9 although the limited sensitivity and specificity have been criticized. 10 Thus, it would be encouraging if 2DSE performed at rest could improve the diagnostic accuracy of the exercise test because both an Background-Two-dimensional strain echocardiography detects early signs of left ventricular dysfunction; however, it is unknown whether myocardial strain analysis at rest in patients with suspected stable angina pectoris predicts the presence of coronary artery disease (CAD). Methods and Results-In total, 296 consecutive patients with clinically suspected stable angina pectoris, no previous cardiac history, and normal left ventricular ejection fraction were included. All patients were examined by 2-dimensional strain echocardiography, exercise ECG, and coronary angiography. Two-dimensional strain echocardiography was performed in the 3 apical projections. Peak regional longitudinal systolic strain was measured in 18 myocardial sites and averaged to provide global longitudinal peak systolic strain. Duke score, including ST-segment depression, chest pain, and exercise capacity, was used as the outcome of the exercise test. Patients with an area stenosis ≥70% in ≥1 epicardial coronary artery were categorized as having significant CAD (n=107). Global longitudinal peak systolic strain was significantly lower in patients with CAD compared with patients without (17.1±2.5% versus 18.8±2.6%; P<0.001) and remained an independent predictor of CAD after multivariable adjustment for baseline data, exercise test, and conventional echocardiography (odds ratio, 1.25 [P=0.016] per 1% decrease). Area under receiver operating characteristic curve for exercise test and global longitudinal peak systolic strain in combination was significantly higher than that for exercise test alone (0.84 versus 0.78; P=0.007). Furthermore, impaired regional longitudinal systolic strain identifies which coronary artery is stenotic. Conclusions-In patients with suspected stable angina pectoris, global longitudinal peak systolic strain assessed at rest is an independent predictor of significant CAD and significantly improves the diagnostic performance of exercise test. Furthermore, 2-dimensional strain echocardiography seems capable of identifying high-risk patients. (Circ Cardiovasc Imaging. 2014;7:58-65.)Key Words: coronary artery disease ◼ diagnostic performance ◼ myocardial ischemia ◼ stable angina pectoris ◼ two-dimensional speckle tracking echocardiography ◼ two-dimensional strain echocardiography