Unmasking Syndrome X
Authors:   Cardiovascular Research Laboratories, Methodist Hospital, Merrillville, IN, USA, Nguyen Thach ,   Tan Tao University, School of Medicine, Long An, Vietnam, Ngo Tra ,   Weiss Memorial Hospital, Chicago, IL, USA, H Nguyen Duc ,   Cardiovascular Research Laboratories, Methodist Hospital, Merrillville, IN, USA, Nguyen Bao ,   Cardiovascular Research Laboratories, Methodist Hospital, Merrillville, IN, USA, Nguyen Nga ,   Cardiovascular Research Laboratories, Methodist Hospital, Merrillville, IN, USA, Chung Duy ,   Cardiovascular Research Laboratories, Methodist Hospital, Merrillville, IN, USA, Ngo Luan ,   Cardiovascular Research Laboratories, Methodist Hospital, Merrillville, IN, USA, Tran Hadrian ,   Cardiovascular Research Laboratories, Methodist Hospital, Merrillville, IN, USA, Mihas Imran ,   Indiana University, Bloomington, IN, USA, Agarewal Sarthak ,   The University of Chicago, Pritzer School of Medicine, Chicago, IL, USA, Nguyen Cardy ,   University of California at Berkeley, Berkeley, CA, USA, Thuong Ho Dung ,   Thong Nhat Hospital, Ho Chi Minh City, Vietnam, Nanjundappa Aravinda ,   Peripheral Interventions, Cleveland Clinics, Cleveland, OH, USA, T Vu Loc ,   Tan Tao University, School of Medicine, Long An, Vietnam; University of Medicine and Pharmacy at Hochiminh city, Vietnam, Agarwal Sanyaa ,   Chesterton High School, Chesterton, IN, USA, Talarico Ernest ,   Cardiovascular Research Laboratories, Methodist Hospital, Merrillville, IN, USA; Tan Tao University, School of Medicine, Long An, Vietnam, Zuin Marco ,   Department of Translational Medicine University of Ferrara, Ferrara, Italy, Rigatelli Gianluca ,   Department of Cardiology, Madre Teresa Hospital, Schiavonia, Italy, Gibson Michael ,   Baim Institute of Clinical Research, Harvard Medical School, Boston, MA, USA
Published: November 2022

Background. The differential diagnosis of chest pain in women is complex, ranging from atypical angina to chest pain in the absence of coronary artery disease (i.e., Syndrome X). The mechanism of these conditions remains unexplained. The purpose of this study was to examine coronary blood flow based on a new angiographic technique. Methods. Patients with chest pain were enrolled. In the new technique, as the contrast injection stopped, the blood in white color moved in and displaced the black contrast. Characteristics of blood flow could be observed and classified by type and time. The duration of the arterial phase was calculated and compared with the control. Results. Sixty patients were enrolled. Ten patients with normal coronary arteries and ventricular function; without chest pain served as controls. In the control group, the duration of the arterial phase in the RCA was 1.76 sec, while it was 3.76 sec for the syndrome X group (p<0.05). From the mMID segment to the distal segment, syndrome X patients had a much longer delay compared to control subjects (0.81 vs. 0.26 sec) (p<0.05). From the distal segment (bDIS) to the origin of the PDA, syndrome X patients had an average duration of 0.81 sec compared to 0.40 sec in controls (p<0.05). The largest difference was the period of time when the contrast left the PDA until flushed from the distal vasculature, which was 1.66 sec and 0.40 sec in syndrome X vs. control. Syndrome X patients with prolonged myocardial phase (1.89 sec) had dense and prolonged contrast retention at the myocardium. Conclusions. In patients with syndrome X, the prolonged arterial phase deprived the myocardium of highly oxygenated blood and triggered ischemia. This new imaging method allows for a better understanding of the mechanism of ischemia in Syndrome X patients.