title: Impact of attenuated plaques on TIMI grade flow and clinical outcomes of coronary artery disease patients: a systematic review and meta analysis.
abstract: BACKGROUND
  Plaques with a large necrotic core or lipid pool and thin-cap fibroatheroma manifest as attenuated plaques on intravascular ultrasound (IVUS). Their impact on TIMI grade flow and clinical outcomes remains undefined. We performed a systematic review and meta-analysis to summarize the association between attenuated plaque and distal embolization and clinical outcomes of coronary artery disease (CAD) from pooled data of published eligible cohort studies.
  
  
  METHODS
  We searched the literature on TIMI grade flow and clinical outcomes on PubMed, Ovid, EMBASE, the Cochrane Library, CNKI and WanFang databases. Study heterogeneity and publication bias were estimated.
  
  
  RESULTS
  A total of 3,833 patients were enrolled in nine studies. Five studies investigated TIMI grade flow and attenuated plaques. They revealed no difference in TIMI grade flow before percutaneous coronary intervention (PCI) between the attenuated and non-attenuated plaque group (RR =1.25; 95% CI: 0.65 to 2.41; P=0.50). After balloon dilation and stent implantation, the incidence of TIMI 0~2 grade flow in the attenuated plaque group was statistically significant higher than that of the non-attenuated plaque group (RR =4.73; 95% CI: 3.03 to 7.40; P<0.001). Five other studies investigated major cardiovascular events (MACEs) and attenuated plaques and found no difference in MACE rates within three years of follow up.
  
  
  CONCLUSIONS
  Our study presents the evidence that plaque with ultrasound signal attenuation would induce slow/no reflow phenomenon and distal embolization during PCI, but this appearance has no impact on MACE rates within three years.
authors.affiliation: 1 Thirty-three ward, Department of emergency cardiology, Beijing Anzhen hospital, Capital Medical University, Beijing 100029, China ; 2 Center of Clinical Epidemiology & Evidence-based Medicine, Beijing Children's Hospital, Capital Medical University, Beijing 100045, China.
authors.forename: Ruofei
authors.initials: R
authors.lastname: Jia
authors.affiliation: 1 Thirty-three ward, Department of emergency cardiology, Beijing Anzhen hospital, Capital Medical University, Beijing 100029, China ; 2 Center of Clinical Epidemiology & Evidence-based Medicine, Beijing Children's Hospital, Capital Medical University, Beijing 100045, China.
authors.forename: Xiaolu
authors.initials: X
authors.lastname: Nie
authors.affiliation: 1 Thirty-three ward, Department of emergency cardiology, Beijing Anzhen hospital, Capital Medical University, Beijing 100029, China ; 2 Center of Clinical Epidemiology & Evidence-based Medicine, Beijing Children's Hospital, Capital Medical University, Beijing 100045, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.affiliation: 1 Thirty-three ward, Department of emergency cardiology, Beijing Anzhen hospital, Capital Medical University, Beijing 100029, China ; 2 Center of Clinical Epidemiology & Evidence-based Medicine, Beijing Children's Hospital, Capital Medical University, Beijing 100045, China.
authors.forename: Huagang
authors.initials: H
authors.lastname: Zhu
authors.affiliation: 1 Thirty-three ward, Department of emergency cardiology, Beijing Anzhen hospital, Capital Medical University, Beijing 100029, China ; 2 Center of Clinical Epidemiology & Evidence-based Medicine, Beijing Children's Hospital, Capital Medical University, Beijing 100045, China.
authors.forename: Lianmei
authors.initials: L
authors.lastname: Pu
authors.affiliation: 1 Thirty-three ward, Department of emergency cardiology, Beijing Anzhen hospital, Capital Medical University, Beijing 100029, China ; 2 Center of Clinical Epidemiology & Evidence-based Medicine, Beijing Children's Hospital, Capital Medical University, Beijing 100045, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Li
authors.affiliation: 1 Thirty-three ward, Department of emergency cardiology, Beijing Anzhen hospital, Capital Medical University, Beijing 100029, China ; 2 Center of Clinical Epidemiology & Evidence-based Medicine, Beijing Children's Hospital, Capital Medical University, Beijing 100045, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Han
authors.affiliation: 1 Thirty-three ward, Department of emergency cardiology, Beijing Anzhen hospital, Capital Medical University, Beijing 100029, China ; 2 Center of Clinical Epidemiology & Evidence-based Medicine, Beijing Children's Hospital, Capital Medical University, Beijing 100045, China.
authors.forename: Duo
authors.initials: D
authors.lastname: Yang
authors.affiliation: 1 Thirty-three ward, Department of emergency cardiology, Beijing Anzhen hospital, Capital Medical University, Beijing 100029, China ; 2 Center of Clinical Epidemiology & Evidence-based Medicine, Beijing Children's Hospital, Capital Medical University, Beijing 100045, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Meng
authors.affiliation: 1 Thirty-three ward, Department of emergency cardiology, Beijing Anzhen hospital, Capital Medical University, Beijing 100029, China ; 2 Center of Clinical Epidemiology & Evidence-based Medicine, Beijing Children's Hospital, Capital Medical University, Beijing 100045, China.
authors.forename: Zening
authors.initials: Z
authors.lastname: Jin
keywords: Attenuated plaque, intravascular ultrasound (IVUS); coronary artery disease (CAD); distal embolization; major adverse cardiac events (MACE); meta-analysis