Intramyocardial injection of autologous platelet-rich plasma combined with transmyocardial revascularization

Transmyocardial revascularization (TMR) can improve refractory angina but does not consistently demonstrate an effect on myocardial function. Recent studies suggest a synergistic effect between TMR and exogenously supplied growth factors. We evaluated the clinical role of intramyocardial injection of autologous platelet-rich plasma (PRP) in conjunction with TMR. Twenty-five nonrevascularizable patients with class III/IV angina underwent minimally invasive sole therapy TMR during a 5-year period at a single institution. Group 1 (14 patients) underwent TMR alone while group 2 (11 patients) underwent TMR plus injection of PRP (Magellan plasma separator) between TMR channels. Blinded angina assessment and ejection fraction (EF) were measured preoperatively and at 6 months postoperatively. Baseline EF (57 +/- 10% vs. 50 +/- 7%), angina class (3.7 +/- 0.5 vs. 3.7 +/- 0.5), and the number of channels (48 +/- 5 vs. 48 +/- 4) were statistically similar in both groups. At 6 months, two class angina relief was similar in both groups (92% vs. 100%, p = 0.4); however, the TMR + PRP group had a lower average angina score (1.3 vs. 0.4, p = 0.07) and more were angina free (23% vs. 78%, p = 0.04) than the TMR-alone group. EF improved in the TMR + PRP group (-2.0% vs. +9.0%, p = 0.07) compared to the TMR-alone group. Two 30-day morbidities occurred in the TMR-alone group (atrial fibrillation and left pleural effusion) and one mortality occurred in the TMR + PRP group. Intramyocardial injection of autologous PRP combined with TMR may be more efficacious at relieving angina and improving myocardial function than TMR alone.

Transmyocardial laser revascularization

It has been almost a decade since transmyocardial laser revascularization (TMR) was approved for clinical use in the United States. The safety of TMR was demonstrated initially with nonrandomized studies in which TMR was used as the only treatment for patients with severe angina. TMR efficacy was proven after multiple randomized controlled trials. These revealed significant angina relief compared to maximum medical therapy in patients with diffuse coronary disease not amenable to conventional revascularization. In light of these results, TMR has been used as an adjunct to coronary artery bypass grafting (CABG). By definition, patients treated with this combined therapy have more severe coronary disease and comorbidities that are associated with end-stage atherosclerosis. Combination CABG + TMR has resulted in symptomatic improvement without additional risk. The likely mechanism whereby TMR has provided benefit is the angiogenesis engendered by the laser-tissue interaction. Improved perfusion and concomitant improvement in myocardial function have been observed post-TMR. Additional therapies to enhance the angiogenic response include combining TMR with stem cell-based treatments, which appear to be promising future endeavors.