Value of index of microcirculatory resistance in the diagnosis of cardiac syndrome X

Objective To explore the correlation between the index of microcirculatory resistance (IMR) and the corrected thrombolysis in myocardial infarction (TIMI) frame count (CTFC) in patients with cardiac syndrome X (CSX), and to discuss the value of IMR in the diagnosis of CSX. Methods This study selected 28 patients with positive treadmill exercise test (CSX group), and another 28 patients with negative treadmill exercise test (normal control group). First, the baseline CTFC (B-CTFC), and hyperemic CTFC (H-CTFC) were measured. The ratio of B-CTFC and H-CTFC was recorded as CFRCTFC. IMR was calculated by method of thermodilution. Results Proportion of patients with hypertension and diabetes in CSX group was significantly higher than that of normal control group (75% vs 46.4%, 60.7% vs 28.6%, P<0.05). IMR in the CSX group was significantly higher than that in the normal group (39.5±27.6 vs 16.1±5.9, P<0.01). H-CTFC in the CSX group was significantly higher than that in the normal group (13.0±4.2 vs 9.5±2.4, P<0.01). CFRCTFCin the CSX group was significantly lower than that in the normal group (2.0±0.5 vs 2.6±0.5, P<0.01). IMR has significant correlation with CFRCTFC (r=-0.62, P<0.01). Conclusions IMR has a notable association with CFRCTFC calculated from CTFC.IMR can provide clinical application in the evaluation of coronary microcirculation dysfunction, and can be used in the diagnosis of CSX. Key words: Capillary resistance; Microcirculation; Microvascular angina/DI