Assessment of myocardial perfusion by positron emission tomography in patients with end-stage coronary artery disease treated with percutaneous myocardial revascularization.

BACKGROUND Reportedly, patients with persistent refractory angina due to end-stage coronary artery disease (CAD) not amenable to traditional revascularization techniques have experienced symptomatic relief following laser revascularization, either surgical transmyocardial revascularization (TMR) or percutaneous myocardial revascularization (PMR). In spite of several hypotheses (i.e., channel patency, placebo effect, denervation, neoangiogenesis), the mechanism of action and the benefit remains controversial. METHODS A prospective trial utilizing positron emission tomography (PET) was conducted as an attempt to correlate quantified myocardial blood flow (MBF) to clinical improvement following PMR. Thirteen consecutive patients with angina class > II in spite of maximal medical treatment underwent PMR with a holmium: yttrium-aluminum-garnet (Ho:YAG) laser. MBF at rest and under hyperemia was assessed by [(13)N]ammonia PET at baseline, 3 and 6 months following PMR. RESULTS Mean angina class and exercise tolerance time improved at 6 months compared with baseline (P < 0.001). The clinical results were accompanied with an improvement in hyperemic MBF (P = 0.05) and a reduction in minimal coronary resistance (MCR; P < 0.05) in PMR-treated segments. Opposite effects, reduced hyperemic MBF and increased MCR, were observed in nontreated segments. The increase in MCR in nontreated segments revealed the favorable therapeutic impact achieved in PMR-treated segments. CONCLUSION The results of this trial utilizing a quantitative technique to quantify myocardial perfusion link clinical improvement post-PMR to neoangiogenesis and consistently improved microcirculation.