Cardiac support device modifies left ventricular geometry and myocardial structure after myocardial infarction.
BACKGROUND
Whether mechanical restraint of the left ventricle (LV) can influence remodeling after myocardial infarction (MI) remains poorly understood. This study surgically placed a cardiac support device (CSD) over the entire LV and examined LV and myocyte geometry and function after MI.


RESULTS
Post-MI sheep (35 to 45 kg; MI size, 23+/-2%) were randomized to placement of the CorCap CSD (Acorn Cardiovascular, Inc) (MI+CSD; n=6) or remained untreated (MI only; n=5). Uninstrumented sheep (n=10) served as controls. At 3 months after MI, LV end-diastolic volume (by MRI) was increased in the MI only group compared with controls (98+/-8 versus 43+/-4 mL; P<0.05). In the MI+CSD group, LV end-diastolic volume was lower than MI only values (56+/-7 mL; P<0.05) but remained higher than controls (P<0.05). Isolated LV myocyte shortening velocity was reduced by 35% from control values (P<0.05) in both MI groups. LV myocyte beta-adrenergic response was reduced with MI but normalized in the MI+CSD group. LV myocyte length increased in the MI group and was reduced in the MI+CSD group. Relative collagen content was increased and matrix metalloproteinase-9 was decreased within the MI border region of the CSD group.


CONCLUSIONS
A CSD beneficially modified LV and myocyte remodeling after MI through both cellular and extracellular mechanisms. These findings provide evidence that nonpharmacological strategies can interrupt adverse LV remodeling after MI.
Blom
Aaron S
AS
Department of Surgery, University of Pennsylvania Medical Center, Philadelphia, PA, USA.
Mukherjee
Rupak
R
Pilla
James J
JJ
Lowry
Abigail S
AS
Yarbrough
William M
WM
Mingoia
Joseph T
JT
Hendrick
Jennifer W
JW
Stroud
Robert E
RE
McLean
Julie E
JE
Affuso
John
J
Gorman
Robert C
RC
Gorman
Joseph H
JH
Acker
Michael A
MA
Spinale
Francis G
FG
D000199:Actins / Q000032:analysis; D000818:Animals; D003094:Collagen / Q000032:analysis; D005109:Extracellular Matrix / Q000502:physiology; D006353:Heart-Assist Devices; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000032:analysis; D020780:Matrix Metalloproteinase 9 / Q000032:analysis; D009200:Myocardial Contraction; D009203:Myocardial Infarction / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D009206:Myocardium / Q000473:pathology*; D032383:Myocytes, Cardiac / Q000473:pathology / Q000502:physiology; D012756:Sheep; D019714:Tissue Inhibitor of Metalloproteinases / Q000032:analysis; D016277:Ventricular Function, Left; D020257:Ventricular Remodeling
D000199:Actins; D019714:Tissue Inhibitor of Metalloproteinases; D003094:Collagen; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9