Impact of Unstable Angina on Outcomes of Transmyocardial Laser Revascularization Combined With Coronary Artery Bypass Grafting

Long-term outcomes after transmyocardial revascularization

BACKGROUND

Two independent reports documented substantially higher operative mortality associated with transmyocardial revascularization (TMR) when used in isolation than that reported in the premarket clinical trials. To clarify the state of the art, this article assesses temporal trends in the use of TMR, short-term and long-term outcomes, and outcomes stratified by procedure type (TMR only and TMR + coronary artery bypass graft [CABG]) and by the 2 specific TMR devices.

METHODS

The study population included all patients undergoing TMR in isolation or in combination with CABG at 435 cardiothoracic hospitals in the United States participating in the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database (ACSD) from January 2000 through November 2006 (n = 15,386). Analysis of long-term outcomes was accomplished through linkage to Medicare claims data. Short-term and long-term (7 years) adverse outcomes were assessed and compared between the 2 TMR device types.

RESULTS

The use of TMR in conjunction with CABG surgery is increasing. This study showed modest differences in short-term morbidity and mortality between the 2 devices. In combination with CABG, after risk adjustment, patients treated with the holmium:YAG laser (experienced a higher rate of operative mortality (3.5% vs 2.5%; adjusted hazard ratio 1.39, 95% confidence level 1.03 to 1.87) but no difference in the composite short-term rate of major morbidity or mortality, compared with the Heart Laser CO2 transmyocardial revascularization system (PLC Medical Systems, Inc, Milford, MA). However, there were no clinically meaningful differences in long-term results.

CONCLUSIONS

Modest differences in short-term morbidity and mortality between the 2 devices suggest the usefulness of further research.

Long-Term Outcomes After CABG With Concomitant CO2 Transmyocardial Revascularization in Comparison With CABG Alone

OBJECTIVES

: Transmyocardial revascularization (TMR) has been used as an isolated or adjunctive revascularization therapy in patients presumed to have nonbypassable coronary artery disease. The purpose of this study is to evaluate the short- and midterm mortality for patients with complete revascularization using TMR and coronary artery bypass grafting (CABG) compared with those patients with incomplete CABG revascularization and to document long-term follow-up in patients receiving TMR + CABG.

METHODS

: Seventy TMR + CABG patients were cohort matched with 70 patients undergoing isolated CABG with circumflex coronary artery disease, but with no bypassable distal targets, from 1999 to 2005 at Emory University Hospital. The data were retrospectively reviewed from a database after being prospectively entered. Results are presented in mean ± standard deviation, and Kaplan-Meier curves were created for long-term all-cause mortality.

RESULTS

: The TMR + CABG patients had a similar incidences to the CABG only group for preoperative ejection fraction (50.9 ± 11.2% vs. 50.7 ± 10.3%, P = 0.93), number of grafts (2.6 ± 1.1 vs. 2.5 ± 1.3, P = 0.5), and number of diseased vessels (2.8 ± 0.3 vs. 2.9 ± 0.4, P = 0.26). Off-pump surgery was used more often in the CABG alone group versus the TMR combined with CABG group (74.3% vs. 41.4%, P < 0.001). Postoperatively, there was no statistical difference among the TMR + CABG and the CABG alone groups for intensive care unit length of stay (4.3 ± 7.8 days vs. 2.6 ± 3.4 days, P = 0.026), postsurgical length of stay (7.6 ± 6.1 days vs. 6.8 ± 4.5 days, P = 0.31), stroke events (1.4% vs. 1.4%, P = 1.00), myocardial infarction (4.3% vs. 2.9%, P = 0.65), and 30-day mortality (5.7% vs. 4.3%, P = 0.70). Long-term survival rate was not statistically significant. In addition, 4-year follow-up in the TMR + CABG group had symptom improvement with reduction in New York Heart Association classification for class III/IV (P < 0.0001, baseline vs. 4-year follow-up).

CONCLUSIONS

: The combination of TMR and CABG for complete revascularization is safe and carries no further risk to patients compared with CABG only. CABG + TMR patients tend to have increased resource utilization. Long-term follow-up shows similar survival between the groups. TMR can be a useful adjunct to CABG for complete revascularization.

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.

Perioperative management of patients undergoing transmyocardial laser revascularization

Advanced revascularization strategies continue to uncover a growing number of patients with symptomatic diffuse coronary artery disease. Transmyocardial laser revascularization (TMR) provides significant benefit in terms of improved quality of life and more complete revascularization for these difficult to treat patients when TMR is used as sole therapy or in combination with coronary artery bypass grafting. The safe clinical application of this important procedure relies on diligent perioperative management with appropriate patient selection, intraoperative care that avoids myocardial ischemia, and postoperative pain control along with expeditious reinstitution of antianginal medications. The treatment paradigms learned with the safe application of TMR should prove useful as new therapies to extend our revascularization options are developed.

Guidelines for the Clinical Use of Transmyocardial Laser Revascularization

Patients with chronic, severe angina refractory to medical therapy who cannot be completely revascularized with either percutaneous catheter intervention or coronary artery bypass graft surgery (CABG) are clinically challenging. Transmyocardial laser revascularization (TMR), as sole therapy or as an adjunct to CABG, may be appropriate therapy for these patients. The recommendations are based on a review of the available evidence including expert consensus opinions. The author follows the format of the American Heart Association and the American College of Cardiology guidelines for diagnostic and therapeutic procedures. There are class I indications for sole therapy TMR and class IIA indications for TMR as an adjunct to CABG. TMR is indicated for selected patients: as sole therapy for a subset of patients with refractory angina. It also may be effective as an adjunct to CABG for a subset of patients with angina who cannot be completely revascularized surgically.