Prognostic Analysis Of Patients With Coronary Slow Flow

Objective: Coronary slow flow(CSF)is a non-obstructive coronary artery disease(CAD).During coronary angiography(CAG),coronary lumens are normal or only mild stenosis,but the distal blood flow is slowed down.Although cardiologists have known CSF for nearly 50 years,its pathophysiological mechanism and prognosis are still unclear.Our study aims to investigate the prognosis of patients with CSF.Methods: In this study,a total of 550 patients(n = 550)who were admitted to the Department of Cardiology,Shinan Area,the Affiliated Hospital of Qingdao University for chest pain from January 2010 to January 2015.These patients were selected according to the flow velocity and the degree of coronary artery stenosis during the CAG process,who were divided into two groups: the CSF group(n = 174)(i.e.with coronary artery slow blood flow and do not have ≥40% stenosis in any epicardial coronary artery during the CAG process)and the normal coronary flow(NCF)group(n = 376)(i.e.there is no stenosis in any epicardial coronary artery and with no coronary artery slow blood flow during the CAG process).After collecting general and basic information,personal history and past medical history,the use of drugs and related inspection and auxiliary examination data of patients in the two groups,we conducted the clinical follow-up.The starting point of follow-up is the time of CAG,the median and maximum follow-up times were 4.0 and 9.0 years,respectively(interquartile range 3.0–6.0 years).The primary end point was major adverse cardiovascular and cerebrovascular events(MACCE),and the secondary end point was all-cause death.In this study,we defined MACCE as: sudden cardiac death,myocardial infarction,percutaneous coronary artery intervention(PCI),coronary artery bypass graft(CABG),new arrhythmia(defined as short or continuous ventricular tachycardia,ventricular fibrillation,atrial fibrillation or atrial flutter and II-III degree atrioventricular block)at or more than 6 months after discharge,stroke or cardiac insufficiency(i.e.left ventricular ejection fraction ≤55% or cardiac function Ⅲ-Ⅳ).After collecting relevant follow-up data,we performed statistical analysis based on them.Compared the differences between the two sets of related data and observed whether it has statistical significance,then evaluated the prognosis of patients with CSF.Results:(1)The proportion of males,patients with smoking history and nicorandil taking in the CSF group was significantly higher than that in the NCF group(60.3% vs 37.7%,P <0.001;43.7% vs 23.9%,P <0.001;14.4% vs.6.4%,P = 0.002);serum uric acid(UA)levels and body mass index(BMI)of patients in CSF group were higher than those in NCF group(316.9±82.7mmol/L vs.302.2±78.7mmol/L,P = 0.046;26.4±4.0 to 25.8±3.2,P = 0.029);CSF patients have lower total cholesterol(TC)and low density lipoprotein cholesterol(LDL-C)levels than NCF Group(4.28±1.0mmol/L vs.4.51±1.0mmol/L,P = 0.001;2.34mmol/L±0.7mmol/L vs.2.50mmol/L±0.8mmol/L,P = 0.018).(2)The Kaplan-Meier method was used to determine the primary end point events and secondary events that occurred in the two groups after follow-up survival analysis was performed at the end events.Regarding the survival free of MACCE,the CSF group was lower than the NCF group(P = 0.001),and any subgroups of 1VD,2VD,and 3VD in the CSF group were also lower than the NCF group(P = 0.001);Regarding the survival,the CSF group was lower than the NCF group(P = 0.006),and any subgroups of 1VD,2VD,and 3VD in the CSF group were also lower than the NCF group(P = 0.016).At the same time,the multivariable-adjusted Cox risk regression model was used to calculate the hazard ratios(HR),and it was found that the risk of MACCE and all-cause death in patients in the CSF group was higher than that in the NCF group,which were HR = 5.89(95 % CI: 1.70-20.43;P = 0.005)and HR = 4.68(95% CI: 1.26-17.36;P =0.021).3 patients with sudden cardiac death in the CSF group whose CSF involved in RCA,LAD + RCA and LAD + RCA + LCX.(3)The proportion of patients with recurrent chest pain(i.e.the frequency of chest pain ≥3 times per week and continuous occurrence for 1 month and above)after discharge in the CSF group was significantly higher than that in the NCF group(22.4% vs.12.5%,P = 0.003).(4)In the CSF group,a single coronary artery involvement has the largest proportion of CSF(44.25%),followed by 3 vessels(30.46%),and 2 vessels(25.29%).Conclusions: 1.Patients with male,smoking history,obesity and elevated blood UA levels may be more likely to have CSF.2.Patients with CSF are more likely to relapse chest pain after discharge.3.Patients with CSF had an increased risk of MACCE and all-cause death which suggested that the prognosis of patients with CSF is poor.