The Society of Thoracic Surgeons practice guideline series: transmyocardial laser revascularization

Remodeling Failing Human Myocardium With Hybrid Cell/Matrix and Transmyocardial Revascularization

Given the limited treatment options for advanced heart failure, the intrinsic regenerative properties of stem cells have been evaluated for myocardial remodeling. Previous stem cells techniques for myocardiocyte remodeling have been limited by the low cellular retention. Presented is a hybrid approach for remodeling infarcted myocardium through implantation of allogeneic human amniotic fluid-derived mesenchymal stem cells within micronized human allograft-derived liquid matrix during the performance of transmyocardial revascularization (TMR). Given the induced increase in vascular density from TMR, we hypothesize that it may serve as a therapeutic delivery system for stem cell placement into damaged myocardium. We present a patient with ischemic cardiomyopathy and refractory angina, who clinically improved after this hybrid therapy of intraoperative TMR and placement of amniotic fluid-derived mesenchymal stem cells and liquid matrix within the TMR channels. Noninvasive testing of myocardial viability biomarkers utilizing both cardiac magnetic resonance imaging and thallium imaging supported the clinical improvement in cardiac symptom may be related to ventricular remodeling in a region of infarct with subsequent functional improvement.

Transmyocardial revascularization (TMR): current status and future directions

Purpose

Cardiac surgeons are increasingly faced with a more complex patient who has developed a pattern of diffuse coronary artery disease (CAD), which is refractory to medical, percutaneous, and surgical interventions. This paper will review the clinical science surrounding transmyocardial revascularization (TMR) with an emphasis on the results from randomized controlled trials.

Methods

Randomized controlled trials which evaluated TMR used as sole therapy and when combined with coronary artery bypass grafting were reviewed. Pertinent basic science papers exploring TMR's possible mechanism of action along with future directions, including the synergism between TMR and cell-based therapies were reviewed.

Results

Two laser-based systems have been approved by the United States Food and Drug Administration (FDA) to deliver laser therapy to targeted areas of the left ventricle (LV) that cannot be revascularized using conventional methods: the holmium:yttrium-aluminum-garnet (Ho:YAG) laser system (CryoLife, Inc., Kennesaw, GA) and the carbon dioxide (CO₂) Heart Laser System (Novadaq Technologies Inc., (Mississauga, Canada). TMR can be performed either as a stand-alone procedure (sole therapy) or in conjunction with coronary artery bypass graft (CABG) surgery in patients who would be incompletely revascularized by CABG alone. Societal practice guidelines have been established and are supportive of using TMR in the difficult population of patients with diffuse CAD.

Conclusions

Patients with diffuse CAD have increased operative and long-term cardiac risks predicted by incomplete revascularization. The documented operative and long-term benefits associated with sole therapy and adjunctive TMR in randomized trials supports TMR's increased use in this difficult patient population.

Newer Therapies for Management of Stable Ischemic Heart Disease With Focus on Refractory Angina

Ischemic heart disease remains a major public health problem nationally and internationally. Stable ischemic heart disease (SIHD) is one of the clinical manifestations of ischemic heart disease and is generally characterized by episodes of reversible myocardial demand/supply mismatch, related to ischemia or hypoxia, which are usually inducible by exercise, emotion, or other stress and reproducible-but which may also be occurring spontaneously. Improvements in the treatment of acute coronary syndromes along with increasing prevalence of cardiovascular risk factors, including diabetes and obesity, have led to increasing population of patients with SIHD. A significant number of these continue to have severe angina despite medical management and revascularization procedures performed and may progress to refractory angina. This article reviews the newer therapies in the treatment of SIHD with special focus in treating patients with refractory angina.

Robotically assisted, completely endoscopic transmyocardial revascularization is feasible

OBJECTIVE

The purpose of this study was to assess the feasibility of an endoscopic, optical-fiber-based, laser delivery system (LDS) developed to perform sole-therapy transmyocardial revascularization (TMR) in a totally endoscopic, robotically assisted operation.

METHODS

Forty-two patients were enrolled in a multicenter, prospective, single-arm clinical trial conducted at four US centers between 2005 and 2007. Transmyocardial revascularization was performed completely endoscopically with robotic assistance, introducing the Holmium:Yttrium aluminum garnet (YAG) LDS via a 5-mm port. Completion of the operation endoscopically defined procedural success. Clinical data were recorded before, during, and at least 30 days after the procedure.

RESULTS

All patients had Canadian Cardiovascular Score angina class IV at baseline. The mean ejection fraction was 49% (range [R], 28-71), the mean age was 59.1 years (R, 36-80), 71% (30/42) were men, 86% (36/42) underwent previous coronary artery bypass grafting surgery, and 76% (32/42) underwent prior coronary stenting. Procedural success was accomplished in 93% (39/42). For the procedural successes, the mean number of TMR channels was 32 (R, 16-50), the median operative time was 88 minutes (R, 48-250 minutes), and the median length of stay postoperatively was 2.5 days (R, 1-10). There was no operative or 30-day mortality, and no patient received any transfusion. At 30 days, freedom from major adverse cardiac events was 95% (two patients had transient congestive heart failure). At the median 6-month follow-up (single-center data, n = 12), the mean (SD) Canadian Cardiovascular Score angina score was 1.3 (0.05) (P < 0.001 vs baseline).

CONCLUSIONS

Robotically assisted TMR can be performed using an endoscopic, optical-fiber-based LDS, with high procedural success, avoidance of early adverse clinical events, and potential for successful angina relief.

Alternative therapy for medically refractory angina: enhanced external counterpulsation and transmyocardial laser revascularization

Medically refractory angina pectoris (RAP) is defined by presence of severe angina with objective evidence of ischemia and failure to relieve symptoms with coronary revascularization. Medication and invasive revascularization are the most common approaches for treating coronary artery disease (CAD). Although symptoms are eliminated or alleviated by these invasive approaches, the disease and its causes are present after treatment. New treatment approaches are needed to prevent the disease from progressing and symptoms from recurring. External enhanced counterpulsation therapy provides a treatment modality in the management of CAD and can complement invasive revascularization procedures. Data support that it should be considered a first-line treatment of RAP.

Transmyocardial revascularization devices: technology update

Transmyocardial laser revascularization (TMR) emerged as treatment modality for patients with diffuse coronary artery disease not amendable to percutaneous or surgical revascularization. The procedure entails the creation of laser channels within ischemic myocardium in an effort to better perfuse these areas. Currently, two laser devices are approved by the US Food and Drug Administration for TMR – holmium:yttrium–aluminum–garnet and CO₂. The two devices differ in regard to energy outputs, wavelengths, ability to synchronize with the heart cycle, and laser–tissue interactions. These differences have led to studies showing different efficacies between the two laser devices. Over 50,000 procedures have been performed worldwide using TMR. Improvements in angina stages, quality of life, and perfusion of the myocardium have been demonstrated with TMR. Although several mechanisms for these improvements have been suggested, evidence points to new blood vessel formation, or angiogenesis, within the treated myocardium, as the major contributory factor. TMR has been used as sole therapy and in combination with coronary artery bypass grafting. Clinical studies have demonstrated that TMR is both safe and effective in angina relief long term. The objective of this review is to present the two approved laser devices and evidence for the safety and efficacy of TMR, along with future directions with this technology.

Holmium:YAG laser system for transmyocardial revascularization

Transmyocardial revascularization, using the US FDA-approved holmium: yttrium-aluminum-garnet (Ho:YAG) laser system, is a surgical option for patients with debilitating angina caused by diffuse coronary artery disease in areas of the heart not amenable to complete revascularization using conventional treatments. Increased utilization of this therapy is warranted, in parallel with continuing research into therapeutic or cell-based methods for enhancing the clinically relevant, positive outcomes. This article will review the clinical science surrounding Ho:YAG transmyocardial revascularization with an emphasis on the randomized controlled trials performed in these patient groups.

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.

Fast Track Minimally Invasive Transmyocardial Revascularization

Objective

We evaluated the initial results of a fast-track discharge protocol for patients undergoing minimally invasive transmyocardial revascularization (MiTMR).

Methods

Fifteen male patients, aged 64.5 ± 9.2 years, with an ejection fraction of 46.8% ± 9.9%, underwent MiTMR through a mini-left anterior thoracotomy aided by robotic-controlled thoracoscopic assistance. A postoperative management protocol included immediate extubation, early chest tube and pulmonary artery catheter removal, and mobilization within 12 hours.

Results

There were no operative arrhythmias or in-hospital mortalities. Three of 15 patients developed left lower lobe atelectasis, delaying discharge between 2 and 5 days. Overall hospital length of stay was 1.4 ± 1.2 days, although 12 of 15 patients (80%) were discharged to home in 23 hours. Mild-moderate cardiomyopathy (ejection fraction 30%–50%) was not associated with prolonged length of stay. Mean hospital profit margin was $1882.50. One 30-day readmission occurred on day 23 for rapid atrial fibrillation, and one death occurred on day 11.

Conclusions

Despite these high-risk patients having end-staged, ischemic coronary artery disease, most MiTMR patients can be discharged to home in less than 24 hours. Perioperative morbidity and mortality rates are relatively low, and hospital profit margins are modest.

Transmyocardial laser revascularization: from randomized trials to clinical practice. A review of techniques, evidence-based outcomes, and future directions

Cardiac surgeons are increasingly faced with a more complex patient who has developed a pattern of diffuse coronary artery disease that cannot be completely revascularized by CAGB alone. Considering the increased operative and long-term cardiac risks predicted by incomplete revascularization, and the documented operative and long-term benefits associated with sole therapy and adjunctive TMR in randomized patients with diffuse coronary artery disease, increased use of sole therapy and adjunctive TMR therapy is warranted.

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.

Transmyocardial revascularization to enhance myocardial vasculogenesis and hemodynamic function

OBJECTIVE

A significant number of patients have coronary artery disease that is not amenable to traditional revascularization. Prospective, randomized clinical trials have demonstrated therapeutic benefits with transmyocardial laser revascularization in this cohort. The molecular mechanisms underlying this therapy, however, are poorly understood. The focus of this study was evaluation of the proposed vasculogenic mechanisms involved in transmyocardial laser revascularization.

METHODS

Male Yorkshire pigs (30-35 kg, n = 25) underwent left thoracotomy and placement of ameroid constrictors around the proximal left circumflex coronary artery. During the next 4 weeks, a well-defined region of myocardial ischemia developed, and the animals underwent a redo left thoracotomy. The animals were randomly assigned to sham treatment (thoracotomy only, control, n = 11) or transmyocardial laser revascularization of hibernating myocardium with a holmium:yttrium-aluminum-garnet laser (n = 14). After an additional 4 weeks, the animals underwent median sternotomy, echocardiographic analysis of wall motion, and hemodynamic analysis with an ascending aortic flow probe and pulmonary artery catheter. The hearts were explanted for molecular analysis.

RESULTS

Molecular analysis demonstrated statistically significant increases in the proangiogenic proteins nuclear factor kappaB (42 +/- 27 intensity units vs 591 +/- 383 intensity units, P = .03) and angiopoietin 1 (0 +/- 0 intensity units vs 241 +/- 87 intensity units, P = .003) relative to sham control values with transmyocardial laser revascularization within the ischemic myocardium. There were also increases in vasculogenesis (18.8 +/- 8.7 vessels/high-power field vs 31.4 +/- 10.2 vessels/high-power field, P = .02), and perfusion (0.028 +/- 0.009 microm3 blood/microm3 tissue vs 0.044 +/- 0.004 microm3 blood/microm3 tissue, P = .01). Enhanced myocardial viability was demonstrated by increased myofilament density (40.7 +/- 8.5 cardiomyocytes/high-power field vs 50.8 +/- 7.5 cardiomyocytes/high-power field, P = .03). Regional myocardial function within the treated territory demonstrated augmented contractility. Global hemodynamic function was significantly improved relative to the control group with transmyocardial laser revascularization (cardiac output 2.1 +/- 0.2 L/min vs 2.7 +/- 0.2 L/min, P = .007, mixed venous oxygen saturation 64.7% +/- 3.6% vs 76.1% +/- 3.4%, P = .008).

CONCLUSION

Transmyocardial laser revascularization with the holmium-YAG laser enhances perfusion, with resultant improvement in myocardial contractility.

Long-term results following percutaneous myocardial laser therapy

OBJECTIVES

The usefulness and safety of percutaneous myocardial laser therapy in selected patients have been identified in previous 1-year randomized trial reports, including that from a double-blind, sham-controlled trial we independently conducted. We aimed to determine whether the 1-year effects are maintained through a long-term, longitudinal follow-up.

METHODS

Patients (n=77) with chronic, stable, medically refractory angina (class III or IV) not amenable to conventional revascularization and with evidence of reversible ischemia, ejection fraction > or =25%, and myocardial wall thickness > or =8 mm were treated with percutaneous myocardial laser. After the 1-year follow-up and disclosure of all randomized assignments as prespecified in the respective study protocol, patients were followed up longitudinally for a mean of 3 years for angina class, left ventricular ejection fraction, medication usage, and adverse events.

RESULTS

No procedural mortality, myocardial infarction, or cerebral embolism occurred. Pericardiocentesis was required in two patients (2.6%). Cardiac event-free survival was 88% at 1 year and 66% at late follow-up. Mean Canadian Cardiovascular Society angina class was significantly improved from baseline (3.2+/-0.4) at 1 year (2.2+/-1.1, P<0.001) and at a mean of 3 years (1.9+/-1.2, P<0.001). Nitrate usage was significantly reduced at late follow-up; however, ejection fraction did not change over time. In a multivariate analysis, angina improvement at 1 year was found to be a significant independent predictor of both survival and angina improvement at late follow-up.

CONCLUSION

We conclude that percutaneous myocardial laser therapy in selected patients with severe, medically refractory angina not treatable with conventional revascularization induces significant and sustained symptomatic benefit.

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.

Transmyocardial laser revascularization causes sustained VEGF secretion

Transmyocardial laser revascularization (TMR) using a carbon dioxide (CO(2)) laser has been shown to relieve angina, increase vascular density, and improve myocardial contraction. A study of 28 patients receiving TMR was conducted to monitor vascular endothelial growth factor (VEGF) levels with the goal of clarifying the relationship between TMR, the amelioration of angina, and vascular density. Serum VEGF levels were measured during four periods (preoperative, postoperative, convalescence, and late) in these 28 patients who received sole therapy TMR for un-revascularizable ischemic angina and the levels were compared with the control group consisting of 10 nonischemic thoracotomy patients. Twelve of the 28 patients had previous coronary artery bypass graft(s); 10 had unstable angina, and 1 had an ejection fraction less than 30%. Overall, angina class was reduced from 3.8 +/- 0.9 to 1.0 +/- 0.9 (P < 0.01) at the 1-year follow-up. There were no perioperative mortalities; however, there was one late mortality. The results show that VEGF levels were higher in the convalescence and late periods. Specifically in the late period, VEGF levels in TMR therapy patients surpassed those of the control group and normalized VEGF levels were three times higher in the late period than preoperatively. The sustained VEGF secretion observed in this study may help to explain why CO(2) TMR therapy causes locally increased vascular density and angina relief.

Clinical results of sole therapy TMR treatment

The safety and efficacy of transmyocardial laser revascularization (TMR) is best demonstrated by the data collected from several multi-institutional randomized controlled trials. These trials are an important link between the preclinical data and the most common use of TMR (TMR + Coronary Artery Bypass Grafting). In addition to significant symptomatic relief both short- and long-term objective data were also garnered in these studies. A review of the history, study design, and outcomes is provided.

Transmyocardial laser revascularization as an adjunct to coronary artery bypass grafting

Many patients with angina related to coronary artery disease respond to medical management or can be completely revascularized using available percutaneous coronary interventions or coronary artery bypass grafting (CABG). There is evidence, however, to indicate that up to 25% of patients are incompletely revascularized following CABG and that incomplete revascularization is a significant independent predictor of early and late mortality and adverse events. Transmyocardial revascularization (TMR) is a surgical option for patients with debilitating angina due to coronary artery disease in areas of the heart not amenable to complete revascularization using conventional treatments. In randomized, 1-year controlled trials with long-term follow-up and in additional clinical experience, TMR performed adjunctively to CABG in patients who would be incompletely revascularized by CABG alone has yielded significantly improved clinical outcomes. Based on these published results, the Society of Thoracic Surgeons has issued a practice guideline recommending adjunctive TMR in this difficult patient group.

Angina pectoris: evaluation in the office

Angina pectoris is a clinical manifestation of myocardial ischemia. Complete evaluation consists of a review of risk factors, a careful history, and, typically, a provocative test. Stress testing can be performed with exercise(treadmill, bicycle, or arm ergometry) or pharmacologic agents that increase cardiac work (dobutamine) or dilate the coronary vessels (adenosine or dipyridamole). Patients who have high-risk features found by clinical history or by stress testing should be referred for coronary angiography and possible revascularization. Comprehensive management of patients who have angina (with or without revascularization) includes smoking cessation,diet and weight control, vasculoprotective drugs (aspirin, statins, and possibly ACE inhibitors), and antianginal medications (nitrates, D-blockers, and calcium channel blockers). These strategies have led to an important reduction in morbidity and mortality over the past 2 decades, and the focus on implementing guidelines for patients who are currently undertreated is expected to improve outcomes further.

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.

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

BACKGROUND

For sole therapy transmyocardial laser revascularization (TMR), unstable angina has been demonstrated to be a significant independent predictor of operative mortality. The objective of this study was to investigate the preoperative risk profile of patients undergoing TMR plus coronary artery bypass graft surgery (CABG) and to determine the impact of unstable angina on outcomes.

METHODS

Using The Society of Thoracic Surgeons National Cardiac Database from 1998 to 2003, 5,618 patients underwent TMR plus CABG. These patients were compared with 932,715 patients who underwent CABG only operations.

RESULTS

The TMR plus CABG patients had a significantly higher incidence of diabetes (50% versus 34%), renal failure (7% versus 5%), peripheral vascular disease (20% versus 16%), reoperative surgery (26% versus 9%), three-vessel coronary artery disease (80% versus 71%), hyperlipidemia (73% versus 62%; p < 0.001 for all comparisons). The incidence of preoperative unstable angina was similar (46% versus 47%). The unadjusted perioperative mortality was 3.8% for TMR plus CABG patients. When unstable angina patients were removed, the observed mortality for TMR plus CABG was decreased to 2.7%.

CONCLUSIONS

It is likely that patients who undergo TMR plus CABG have a higher prevalence of diffuse coronary disease based on their preoperative demographics. Despite the increased risk associated with such anatomy, the mortality rate was not significantly increased when TMR was added to CABG in an effort to provide a more complete revascularization. As was noted from the outcomes of sole therapy TMR, in unstable angina patients, TMR plus CABG carries a higher risk, but this risk is not significantly different from that of such patients treated with CABG alone.

Mid-Term Results After Thoracoscopic Transmyocardial Laser Revascularization

BACKGROUND

Transmyocardial revascularization is a surgical therapy for the relief of severe angina in patients who are not suitable candidates for coronary artery bypass graft surgery or percutaneous coronary interventions. Historically, surgical techniques employed a left thoracotomy with or without thoracoscopic assist for visualization. This study evaluated the feasibility and midterm outcomes after transmyocardial laser revascularization performed using a completely thoracoscopic, closed chest approach.

METHODS

Patients (9 men [90%] and 1 woman [10%]) at a mean age of 66 +/- 10 years who were ineligible for coronary artery bypass graft surgery or percutaneous coronary intervention underwent sole therapy transmyocardial laser revascularization using a completely thoracoscopic surgical approach using a holmium:yttrium-aluminum-garnet laser system. Preoperatively, patients had a mean ejection fraction of 0.51 +/- 0.09 and a mean angina class of 3.7 +/- 0.5.

RESULTS

A mean of 30 +/- 2.4 channels were created during mean laser and operative procedure times of 14 +/- 2.9 and 133 +/- 32 minutes, respectively. Patients were extubated at a mean of 7.6 +/- 12 hours and were discharged from the hospital at a mean of 5.4 +/- 3.4 days. There were no hospital deaths or major complications. At a mean of 8.4 +/- 5.5 months postoperatively, all patients survived and significant clinical improvement with a mean angina class of 1.3 +/- 0.5 (p < 0.001).

CONCLUSIONS

A completely thoracoscopic surgical approach is feasible for sole therapy transmyocardial revascularization that affords improved visualization over a limited thoracotomy approach. Limited complications and significant clinical improvement after the procedure were observed. With minimal port manipulation, there is an opportunity for decreased postoperative pain; however, larger studies are warranted to verify this hypothesis.

Management Options for Angina Refractory to Maximal Medical and Surgical Interventions

Despite the seemingly daily advances in the primary, secondary, and tertiary prevention for coronary artery disease, many patients will ultimately experience progression of their disease and experience angina refractory to further active treatment. In these patients, disabling angina occurs at rest or during simple activities of daily living. When this occurs, symptom management, a predominant focus of nursing, becomes the goal of care. Several medical and surgical alternatives are available to patients with refractory angina. Enhanced external counterpulsation and transmyocardial laser revascularization are Food and Drug Administration approved therapies that can be used to attempt to restore the balance of supply and demand. Modulation of sympathetic tone via procedures such as stellate ganglion blocks has also been employed. Other methods to control the pain are techniques that alter pain perception such as spinal opioids, transcutaneous electrical nerve stimulation, and spinal cord stimulation. Too few patients with refractory angina are referred for any of these palliative therapies. Armed with knowledge regarding these therapies, nurses will be better prepared to provide anticipatory guidance to patients and their families and to support the patient's hope for relief as they cope with this devastating condition.

Adjunctive transmyocardial revascularization: five-year follow-up of a prospective, randomized trial

BACKGROUND

In a prospective, randomized trial involving 263 patients who would be incompletely revascularized by coronary artery bypass grafting (CABG) alone, CABG plus transmyocardial revascularization (CABG/TMR) provided an early mortality benefit with similar angina relief compared with CABG alone at 1 year. We evaluated the long-term outcome of patients randomized to CABG/TMR or CABG alone.

METHODS

Thirteen centers that enrolled 83% (218/263) of the patients in the original trial participated in this longitudinal study. Between 1996 and 1998, these centers randomized 218 patients who would be incompletely revascularized by CABG alone because of diffusely diseased target vessels to either holmium:yttrium-aluminum-garnet (holmium:YAG) CABG/TMR (n = 110) or CABG alone (n = 108). Baseline demographics and operative characteristics were similar between groups. Follow-up (mean 5.0 +/- 1.7 years) included survival and blinded angina class assessment.

RESULTS

At this 5-year follow-up both groups experienced significant angina improvement from baseline, however, the CABG/TMR group had a lower mean angina score (0.4 +/- 0.7 vs 0.7 +/- 1.1, p = 0.05), a significantly lower proportion of patients with severe angina (class III/IV: 0% [0/68] vs 10% [6/60], p = 0.009), and a trend towards greater number of angina-free patients (78% [53/68] vs 63% [38/60], p = 0.08), compared with CABG alone patients. Kaplan-Meier survival at 6 years was similar between CABG/TMR and CABG alone patients (76% vs 80%, p = 0.90).

CONCLUSIONS

Five-year follow-up of prospectively randomized patients who would be incompletely revascularized because of diffuse coronary artery disease indicates that the addition of TMR to conventional CABG provides superior angina relief compared to CABG alone.