BACKGROUND Previous reports of transmyocardial revascularization (TMR) indicate a significant mortality in patients with refractory, unstable angina. We hypothesized that TMR with a holmium laser would result in significant angina relief with acceptable mortality in this patient population. RESULTS Patients were defined as unstable if they were unweanable from intravenous antianginal medications or were too unstable for a persantine thallium scan. Patients had a left ventricular ejection fraction (LVEF) of > 25% and were not amenable to CABG or PTCA. Before treatment, all patients had class IV angina. TMR was performed in 85 patients, with a mean of 35 +/- 11 transmural laser channels. Mean age was 63 +/- 10 years. Mean LVEF was 48 +/- 11%. Of these patients, 79% were men. Prior CABG and/or PTCA had been performed in 87% of patients, and 72% of patients had a history of prior MI. Operative mortality was 12% (10 of 85). There were 2 deaths between discharge and 3 months after surgery and 7 late deaths from 6 to 12 months after surgery. Twelve-month mortality was 22.4% (19 of 85). At 3 months, 86% of patients had class II angina or better. At 6 and 12 months, 77% and 75% of patients, respectively, had class II angina or better. Mean angina class at 6 and 12 months' follow-up was 1.5 +/- 1.1 and 1.6 +/- 1.3, respectively. CONCLUSIONS In patients with refractory unstable angina, TMR with a holmium laser provided significant angina relief. Moreover, 30-day operative mortality and 12-month mortality were acceptable, especially given this subset of unstable patients with refractory angina.