Cardiac denervation after clinical transmyocardial laser revascularization: short-term and long-term iodine 123-labeled meta-iodobenzylguanide scintigraphic evidence.

OBJECTIVES: This study was designed to investigate whether transmyocardial laser revascularization induces myocardial denervation and to correlate this with myocardial perfusion and clinical status.
METHODS: Transmyocardial laser revascularization was performed with a Holmium:YAG (n = 3) or xenon chloride excimer laser (n = 5). Preoperative and postoperative iodine 123-labeled meta-iodobenzylguanide SPECT scintigraphy to assess cardiac innervation and perfusion scintigraphy were also performed. Furthermore, New York Heart Association functional angina class and quality of life were assessed.
RESULTS: In all patients postoperative iodine 123-labeled meta-iodobenzylguanide SPECT showed significantly decreased uptake and therefore sympathetic myocardial denervation at up to 16 months' follow-up (average preoperative and postoperative summed defect scores of 14.8 +/- 5.3 and 24.5 +/- 4.2, respectively; P =.00005). In 86% of segments, the decreased meta-iodobenzylguanide uptake could be correlated to the treated area. In all patients angina was reduced by 2 or more classes at 12 months' follow-up, and quality of life improved significantly.
CONCLUSIONS: Transmyocardial laser revascularization-induced improvement of angina and quality of life can be explained by destruction of nociceptors or cardiac neural pathways, changing the perception of anginal pain.