Abstract 14947: Diagnostic Value of Exercise-Induced Post-Ischemic Left Ventricular Delayed Relaxation or Diastolic Stunning in Patients With Intermediate Coronary Lesions: Comparison With Myocardial Fractional Flow Reserve
Background: Quantitative analysis of prolonged regional left ventricular (LV) diastolic dysfunction or diastolic stunning has provided a more sensitive estimation of the myocardial ischemia. The aim of this study is to evaluate the diagnostic value of diastolic stunning detected by 2D speckle-tracking strain imaging (SI) compared with the invasively assessed myocardial fractional flow reserve (FFR) in patients with intermediate coronary lesion.
Methods: Sixty-one consecutive patients (12 females, mean 66.8 yrs) who had a stenosis of moderate severity in one major coronary artery were recruited. Treadmill exercise echocardiography (TME) with SI study by using a ultrasound system (Atrida; Toshiba Medical Systems), and coronary arteriography with FFR measurements were performed. Patients with abnormal results on TME had stress-induced regional wall motion abnormalities. In SI study, transverse strain images were obtained in each segment at rest and 5 min after treadmill exercise. The end systolic values of strain at the closure of the aortic valve (A) and at the one-third point of diastole duration (B) were measured. The strain imaging diastolic index (SI-DI) was determined as (A - B)/A × 100%, and the ratio of SI-DI before and after exercise (SI-DI ratio) was used to identify regional LV delayed relaxation. A positive SI study was defined as SI-DI ratio ≤ 0.74.
Results: The FFR at maximum hyperemia averaged 0.79 ± 0.10 and 42 patients (69%) had an FFR ≥ 0.75. TME based receiver-operator characteristic (ROC) analysis of FFR yield optimal cutoff value of 0.78. Sensitivity and specificity of FFR were 95% and 100%, respectively. The best cutoff value of FFR by SI study based ROC analysis was 0.83, which yield a sensitivity and specificity of 100% and 95%, respectively. During follow-up period, the CCS functional class of the patients with FFR ≥ 0.83 (n=20) had improved from 2.4 to 1.1 (p <0.05). However, the patients with FFR of 0.76 to 0.82 (n=22) had not improved, from 2.8 to 2.3 (p = 0.13), and 18 patients (82%) underwent coronary intervention.
Conclusions: The detection of LV diastolic stunning by using SI improved the relation between the inducible myocardial ischemia and FFR measurement, and FFR <0.83 could be the best cut-off point to predict cardiac events.
- © 2011 by American Heart Association, Inc.