Latissimus dorsi cardiomyoplasty: a chronic experimental porcine model. Feasibility study of cardiomyoplasty in Danish Landrace pigs and Göttingen minipigs.
Cardiomyoplasty is an experimental treatment for end-stage heart failure. We hypothesized that the porcine latissimus dorsi muscle (LDM) in an experimental porcine model is a suitable surrogate for a clinically relevant evaluation of this concept. Fourteen Danish Landrace (DL) pigs and six Göttingen minipigs (GM) were studied. The LDM was evaluated immediately after surgical dissection and in various phases: phase 1 (n = 4)--outcome of a partial vascular isolation (vascular delay), 2 to 3 weeks prior to heart wrapping in DL pigs; phase 2 (n = 6)--long-term flap survival of nonstimulated LDM cardiomyoplasty in DL pigs; phase 3 (n = 6)--outcome of nonstimulated cardiomyoplasty in GM; phase 4--one DL pig had dynamic cardiomyoplasty performed and was subjected to low-intensity LDM stimulation for 8 months. Isolation of the LDM of DL pigs and GM as a pedicled graft had no acute deleterious impact on the global blood supply. In phase 1a, partial vascular isolation and in situ recovery of the LDM resulted in a muscle encapsulated in fibrotic tissue, which hampered a later heart wrap. In phase 1b, a less extensive dissection diminished fibrosis and allowed subsequent wrapping. In phase 2, after 6 weeks of nonstimulated LDM cardiomyoplasty, the LDM of DL pigs was viable, with excellent heart-muscle integration. In phase 3, the same procedure applied in GM yielded the same result as that in DL pigs, but with a higher success rate owing to the learning phase.