Background: Aortomyoplasty (AMP), a procedure in which the latissimus dorsi muscle (LDM) is wrapped around the aorta and stimulated during diastole, is a potential method of chronic counterpulsation. Counterpulsation by the intraaortic balloon pump (IABP) is a proven treatment for ischemic coronary syndrome and heart failure but cannot be used chronically. This study examined the long-term potential of a unique AMP configuration and compared its performance to the IABP.
Materials and methods: AMP was done using a wringer configuration (AMP-W) in nine dogs. Six and 12 months later, acute hemodynamic augmentation was evaluated by measuring differences in mean diastolic aortic pressure (mDAP), peak left ventricular pressure (pLVP), and the endocardial viability ratio (EVR) between stimulated and unstimulated beats.
Results: The diastolic augmentation obtained by AMP-W at 6 months and by AMP-W and IABP at 12 months was statistically significant. Additionally, the enhancements in EVR (16.1 +/- 4.3%), mDAP (8.6 +/- 2.5%), and pLVP (-1.8 +/- 1.0%) at 6 months were similar to those in EVR (19.1 +/- 5.2%), mDAP (13.1 +/- 3.6%), and pLVP (-0.8 +/- 1.3%) at 12 months. Most importantly, the augmentation obtained by AMP-W at 12 months was similar to that of the IABP: EVR (17.1 +/- 5.9%), mDAP (13.4 +/- 6.7%), and pLVP (-1.5 +/- 0.8%).
Conclusions: AMP-W is a safe, robust procedure, capable of providing counterpulsation equivalent to the IABP, 12 months following surgery. The potential for AMP-W to offer chronic counterpulsation and to benefit the ischemic heart should be investigated further.