title: Efficacy of polymer injection for ischemic mitral regurgitation: persistent reduction of mitral regurgitation and attenuation of left ventricular remodeling.
abstract: OBJECTIVE
  The aim of this study was to examine the chronic effects of polyvinyl-alcohol (PVA) injection on mitral regurgitation (MR) reduction, mitral valve geometry, and left ventricular (LV) remodeling in a chronic ischemic MR sheep model.
  
  
  BACKGROUND
  Previous studies have demonstrated acute efficacy of PVA hydrogel polymer injection into infarcted myocardium underlying the papillary muscle to relieve MR by papillary muscle repositioning. However, the chronic efficacy of PVA injection in the chronic infarction setting remains unclear.
  
  
  METHODS
  Sixteen sheep developed chronic MR 8 weeks after induced inferoposterior myocardial infarction. Ten consecutive sheep underwent PVA injection (PVA group) and 6 sheep served as control subjects with saline injection. Epicardial 2-/3-dimensional echocardiography was performed at the baseline, chronic MR (pre-injection), and sacrifice (8 weeks after injection) stages.
  
  
  RESULTS
  Both groups were comparable at the baseline and chronic MR stages. At sacrifice, MR decreased from moderate to trace or mild (vena contracta: 0.17 ± 0.08 cm vs. 0.56 ± 0.10 cm, p < 0.001) in the PVA group but progressed to moderate to severe in the control group. End-systolic and -diastolic volumes remained stable in the PVA group but increased significantly in the control group (both p < 0.05). At sacrifice, compared with the control group, the PVA group had significantly less left ventricular remodeling (end-systolic volume: 41.1 ± 10.4 ml vs. 55.9 ± 12.4 ml, p < 0.05), lower MR severity (vena contracta: 0.17 ± 0.08 cm vs. 0.60 ± 0.14 cm, p < 0.01), and favorable changes in mitral valve geometry.
  
  
  CONCLUSIONS
  Polymer injection in a chronic ischemic MR model results in persistent reduction of MR and attenuation of continued left ventricular remodeling over 8 weeks of follow-up.
authors.affiliation: Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Xin
authors.initials: X
authors.lastname: Zeng
authors.affiliation: Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Lin
authors.initials: L
authors.lastname: Zou
authors.affiliation: Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Levine
authors.affiliation: Cardiac Surgery Division, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: J Luis
authors.initials: JL
authors.lastname: Guerrero
authors.affiliation: Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Mark D
authors.initials: MD
authors.lastname: Handschumacher
authors.affiliation: Cardiac Surgery Division, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Suzanne M
authors.initials: SM
authors.lastname: Sullivan
authors.affiliation: Cambridge Polymer, Inc., Boston, Massachusetts.
authors.forename: Gavin J C
authors.initials: GJC
authors.lastname: Braithwaite
authors.affiliation: Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: James R
authors.initials: JR
authors.lastname: Stone
authors.affiliation: Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Jorge
authors.initials: J
authors.lastname: Solis
authors.affiliation: Biomaterials Laboratory, Department of Orthopedic Surgery, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Orhun K
authors.initials: OK
authors.lastname: Muratoglu
authors.affiliation: Cardiac Surgery Division, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Gus J
authors.initials: GJ
authors.lastname: Vlahakes
authors.affiliation: Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Boston, Massachusetts. Electronic address: jhung@mgh.harvard.edu.
authors.forename: Judy
authors.initials: J
authors.lastname: Hung
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004452:Echocardiography; D007267:Injections; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging / Q000188:drug therapy*; D011142:Polyvinyl Alcohol / Q000008:administration & dosage / Q000494:pharmacology*; D012756:Sheep; D020257:Ventricular Remodeling / Q000187:drug effects*
chemical_list: C062364:polyvinyl alcohol hydrogel; D011142:Polyvinyl Alcohol
keywords: echocardiography; mitral regurgitation; myocardial infarction; remodeling