AIM To explore the relationship between myocardial ischemia and coronary stenosis in patients with unstable angina pectoris by non-invasive coronary flow reserve (CFR).
METHODS Sixty patients with unstable angina pectoris were selected from January 2016 to December 2018 in our hospital. A total of 94 diseased coronary arteries were examined by coronary flow imaging. The blood flow spectrograms of anterior descending, circumflex and middle and distal right coronary arteries at rest were obtained. The blood flow spectrograms were obtained before ATP injection and within 5 minutes after ATP withdrawal to measure the maximum peak coronary diastolic flow velocity at rest, and CFR was calculated.
RESULTS The cutoff value for CFR was at 2.0. When CFR<2.0 indicated myocardial ischemia, the analysis of non-invasive CFR and coronary angiography showed that CFR decreased significantly with the increase of coronary stenosis rate and there was a negative correlation between them (r = −0.803, P<0.05). CFR was less than 2.0 in 40 lesions of coronary artery and > 2.0 in 54 diseased coronary arteries. The results suggested that the sensitivity of CFR < 2.0 to predict coronary stenosis rate > 70% was 82.7%, the specificity was 87.7%, the positive predictive value was 84.2%, the negative predictive value was 86.5, the number of single vessel lesions was 61, the number of double vessel lesions was 21 and the number of three vessel lesions was 12. Compared with those before treatment, the heart rate, systolic blood pressure, diastolic blood pressure and respiration after 5 minutes of administration and 5 minutes of withdrawal were higher and the difference was significant (P < 0.05, P < 0.01).
CONCLUSION Noninvasive CFR is useful to assess the severity of myocardial ischemia and its relationship with coronary stenosis in patients with unstable angina pectoris.
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