Technetium 99m-labeled tetrofosmin and iodine 123-labeled metaiodobenzylguanidine scintigraphy in the assessment of transmyocardial laser revascularization

Abstract

Objective: Transmyocardial laser revascularization is a new technique that improves symptoms in patients with refractory angina not amenable to conventional revascularization. The aim of this study was to assess whether transmyocardial laser revascularization produces changes in innervation, perfusion scintigraphy, or both that could explain the benefit to patients. Methods: Sixteen patients (12 men and 4 women; mean age, 60 ± 8 years) with coronary artery disease were studied. Transmyocardial laser revascularization was performed in 39 myocardial areas supplied by a stenotic vessel. A technetium 99m-labeled tetrofosmin stress-rest tomographic scan and iodine 123-labeled metaiodobenzylguanidine planar scans were performed before and after transmyocardial laser revascularization (3 and 12 months later) to evaluate myocardial perfusion and innervation. Stress and rest perfusion images were quantified on a polar map. Ischemia uptake was also defined as the difference between rest and stress uptake for each area. Innervation planar images were visually analyzed and semiquantified. Results: A significant decrease in angina class from baseline was observed at 3, 6, and 12 months after transmyocardial laser revascularization ( P < .005). A significant decrease in ischemia uptake was also found between the pre-transmyocardial laser revascularization and the post-transmyocardial laser revascularization studies in treated areas ( P < .001). A significant improvement in stress myocardial perfusion at 3 and 12 months after transmyocardial laser revascularization was only found in treated areas that were considered ischemic in the pre-transmyocardial laser revascularization study ( P < .05). At 3 months, a significant myocardial innervation worsening was observed in treated areas ( P < .001), with partial recovery at 12 months ( P < .05). Conclusion: The transmyocardial laser revascularization mechanism involves both perfusion improvement and denervation, mainly at 3 months, that partially recovered at 12 months.