Improved perfusion and contractile reserve after transmyocardial laser revascularization in a model of hibernating myocardium.


Journal Article

BACKGROUND: Transmyocardial laser revascularization (TMR) has been demonstrated effective for relieving angina, although prior studies have yielded inconsistent results regarding postoperative myocardial perfusion and function. This study evaluated long-term changes in myocardial perfusion and contractile reserve after TMR in a model of hibernating myocardium. METHODS: Miniswine had subtotal left circumflex coronary artery occlusion to reduce resting blood flow to 10% of baseline. After 2 weeks in the low-flow state, positron emission tomography and dobutamine stress echocardiography were performed to document ischemic, viable (hibernating) myocardium in the left circumflex distribution. Animals then had sham redo thoracotomy (n = 4) or TMR (n = 6). Six months later the positron emission tomography and dobutamine stress echocardiography studies were repeated. RESULTS: Myocardial blood flow in the left circumflex distribution as measured by positron emission tomography was significantly reduced in all animals after 2 weeks in the low-flow state. In animals that had TMR, there was significant improvement in myocardial blood flow to the lased regions 6 months postoperatively. No significant change in myocardial blood flow was seen in sham animals at 6 months. Dobutamine stress echocardiography after 2 weeks of low-flow demonstrated severe hypocontractility at rest in the left circumflex region of all animals, with a biphasic response to dobutamine consistent with hibernating myocardium. In animals that had TMR, there was a trend toward improved resting function and significantly improved regional stress function in the lased segments 6 months postoperatively, consistent with a reduction in ischemia. Global left ventricular wall motion at peak stress improved significantly as well. There was no change in wall motion 6 months postoperatively in sham-operated animals. CONCLUSIONS: This study found improvements in myocardial perfusion and regional and global contractile reserve 6 months after TMR in a porcine model of hibernating myocardium. This improved perfusion and function likely accounts for the clinical benefits of the procedure.

Full Text

Duke Authors

Cited Authors

  • Hughes, GC; Kypson, AP; St Louis, JD; Annex, BH; Coleman, RE; DeGrado, TR; Donovan, CL; Lowe, JE; Landolfo, KP

Published Date

  • June 1999

Published In

Volume / Issue

  • 67 / 6

Start / End Page

  • 1714 - 1720

PubMed ID

  • 10391280

Pubmed Central ID

  • 10391280

International Standard Serial Number (ISSN)

  • 0003-4975

Digital Object Identifier (DOI)

  • 10.1016/s0003-4975(99)00317-3


  • eng

Conference Location

  • Netherlands