Clinical outcome of a cohort of patients eligible for therapeutic angiogenesis or transmyocardial revascularization

Pre-arterialization of coronary veins prior to retroperfusion of ischemic myocardium: percutaneous closure device

Background

Chronic coronary retroperfusion to treat myocardial ischemia has previously failed due to edema and hemorrhage of coronary veins suddenly exposed to arterial pressures. The objective of this study was to selectively adapt the coronary veins to become arterialized prior to coronary venous retroperfusion to avoid vascular edema and hemorrhage.

Methods and results

In 32 animals (Group I = 19 and Group II = 13), the left anterior descending (LAD) artery was occluded using an ameroid occlusion model. In Group I, the great cardiac vein was blocked with suture ligation (Group IA = 11) or with occlusion device (Group IB = 8) to arterialize the venous system within 2 weeks at intermediate pressure (between arterial and venous levels) before a coronary venous bypass graft (CVBG) was implemented through a left internal mammary artery (LIMA) anastomosis. Group II only received the LAD artery occlusion and served as control. Serial echocardiograms showed recovery of left ventricular (LV) function with this adaptation-arterialization approach, with an increase in ejection fraction (EF) in Group I from 38% ± 5% after coronary occlusion to 53% ± 7% eight weeks after CVBG, whereas in Group II the EF never recovered (41% ± 2%-33% ± 7%). The remodeling of the venous system not only allowed restoration of myocardial function when CVBG was implemented but possibly promoted a novel form of "collateralization" between the native arterioles and the newly arterialized venules, which revascularized the ischemic myocardium.

Conclusions

These findings form a potential rationale for a venous arterialization-revascularization treatment for the refractory angina and the "no-option" patients using a hybrid percutaneous (closure device for arterialization)/surgical approach (CVBG) to revascularize the myocardium.

Contemporary Management of Refractory Angina

Refractory angina (RA) is defined as chest pain caused by coronary ischemia in patients on maximal medical therapy and is not amenable to revascularization despite advanced coronary artery disease (CAD). The long-term prognosis has improved with optimal medical therapy including risk factor modification. Still, patients are left with major impairment in quality of life and have high resource utilization with limited treatment options. We review the novel invasive and noninvasive therapies under investigation for RA.

Therapeutic Approaches for the No-Option Refractory Angina Patient

The combination of an aging population and improved survival rates among patients with coronary artery disease has resulted in an increase in the number of patients with refractory angina or anginal equivalent symptoms despite maximal medical therapy. Patients with refractory angina are often referred to the cardiac catheterization laboratory; however, they have often exhausted conventional revascularization options; thus, this population is often deemed as having "no options." We review the definition, prevalence, outcomes, therapeutic options, and treatment considerations for no-option refractory angina patients and focus on novel therapies for this complex and challenging population. We propose a multidisciplinary team approach for the evaluation and management of patients with refractory angina, ideally in a designated clinic. The severe limitations and symptomatology experienced by these patients highlight the need for additional research into the development of innovative treatments.

Health Status and Quality of Life of Patients Enrolled in a Specialized Refractory Angina Clinic

As the mortality of coronary artery disease improves and the population ages, an increasing number of patients with refractory angina are not candidates for percutaneous or surgical revascularization. We evaluated the impact of a dedicated refractory angina clinic on quality of life. In 76 patients who completed the Medical Outcomes Study 36-Item Short-Form Health Survey and Seattle Angina Questionnaire at baseline and 1 year, the Medical Outcomes Study results showed the proportion of patients who rated their health as “good” or “excellent” more than doubled from baseline to 1 year (15.8% vs. 42.2%; P < .001). Similarly, the Seattle Angina Questionnaire score was significantly improved at 1 year compared to baseline (P = .025), as were angina stability (P = 0.017) and angina frequency (P = .010). In conclusion, treatment in a dedicated clinic is associated with improved quality of life in patients with refractory angina.

Revascularization in "no option" patients with refractory angina: Frequency, etiology and outcomes

BACKGROUND

A significant proportion of patients with complex, advanced coronary artery disease have refractory angina (RA) despite maximal pharmacological therapy and are deemed suboptimal candidates for revascularization. These patients are frequently termed "no-option" patients. However, despite this designation, many subsequently undergo coronary revascularization. We sought to determine the incidence, etiology and outcome of revascularization in "no-option" patients.

METHODS AND RESULTS

We examined a comprehensive, prospective RA database to identify 342 of 1363 (25.1%) patients who subsequently underwent revascularization after a median interval of 2.2 years from the "no-option" diagnosis. Coronary revascularization was achieved by percutaneous coronary intervention (PCI) (n = 274, 20.1%), coronary bypass graft surgery (n = 44, 3.2%) or both (n = 24, 1.8%). During a median follow-up of 5.1 years, patients who underwent revascularization had lower annual mortality (2% vs. 4.4%, P < .001). Detailed paired angiographic records were available for 181 PCI patients with a combined 302 lesions. Of these interventions, 48% were for a new lesion, 31% for an existing lesion and 21% for restenosis. The location was a native vessel in 77% and a bypass graft in 23%.

CONCLUSIONS

The "no-option" or non-revascularizable designation is frequently based on angiography at a single time-point. However, coronary artery disease is a progressive and dynamic process and new lesions often develop in such patients. Given the association between revascularization and better survival, careful consideration should be given to repeat revascularization in patients with refractory angina previously classified as "no-option".

Safety and efficacy of percutaneous intramyocardial bone marrow cell injection for chronic myocardial ischemia: Long-term results

BACKGROUND

Intramyocardial injection of bone marrow cells (BMC) in refractory angina patients with chronic myocardial ischemia has shown to be safe and improve clinical status during short-term follow-up. However, scarce data are available on long-term (>12 months) safety and efficacy. Therefore, the occurrence of clinical events and the long-term clinical effects of intramyocardial BMC injection were evaluated in patients with chronic myocardial ischemia up to 10 years after treatment.

METHODS AND RESULTS

Patients (n = 100, age 64 ± 9 years, male 88%) with chronic myocardial ischemia who underwent intramyocardial BMC injection between 2004 and 2010 were evaluated. During yearly outpatient clinic visits, the occurrence of clinical events was documented. In addition, clinical status was assessed according to the Canadian Cardiovascular Society (CCS) score and quality of life was measured using the Seattle Angina Questionnaire. These parameters were evaluated at baseline and during the first year, followed by cross-sectional long-term follow-up which was performed in 2011 and 2014. No adverse events considered related to the procedure occurred during 10 years of follow-up. Observed annual mortality rate and annual myocardial infarction rate were 3.8% and 1.9% per year, respectively. When compared to baseline, CCS class and quality of life remained significantly better during 5-year follow-up after BMC treatment (both P < 0.05).

CONCLUSIONS

The present long-term follow-up study shows that intramyocardial BMC injection in patients with chronic myocardial ischemia is safe and improves both angina complaints and quality of life up to 5 years after BMC treatment.

Advancements in pharmacotherapy for angina

INTRODUCTION

Angina pectoris is the most prevalent symptomatic manifestation of ischemic heart disease, frequently leads to a poor quality of life, and is a major cause of medical resource consumption. Since the early descriptions of nitrite and nitrate in the 19th century, there has been considerable advancement in the pharmacologic management of angina. Areas covered: Management of chronic angina is often challenging for clinicians. Despite introduction of several pharmacological agents in last few decades, a significant proportion of patients continue to experience symptoms (i.e., refractory angina) with subsequent disability. For the purpose of this review, we searched PubMed and Cochrane databases from inception to August 2016 for the most clinically relevant publications that guide current practice in angina therapy and its development. In this article, we briefly review the pathophysiology of angina and mechanism-based classification of current therapy. This is followed by evidence-based insight into the traditional and novel pharmacotherapeutic agents, highlighting their clinical usefulness. Expert opinion: Considering the wide array of available therapies with different mechanism efficacy and limiting factors, a personalized approach is essential, particularly for patients with refractory angina. Ongoing research with novel pharmacologic modalities is likely to provide new options for management of angina.

Percutaneous Device to Narrow the Coronary Sinus: Shifting Paradigm in the Treatment of Refractory Angina? A Review of the Literature

Refractory angina pectoris is defined as a chronic debilitating condition characterized by the presence of chronic anginal symptoms due to a severe obstructive and/or diffuse coronary artery disease that cannot be controlled by the combination of medical therapy and/or revascularization (percutaneous or surgical). In addition, the presence of myocardial ischemia as a cause of the symptoms must have been documented. The coronary sinus reducer (CSR) is a recently introduced percutaneous device to treat patients with severe anginal symptoms refractory to optimal medical therapy and not amenable to conventional revascularization. The purpose of this review is to describe the current evidence from available studies measuring the clinical effect of the CSR implantation on the health and well-being of patients with refractory angina.

A prospective study of patients with refractory angina: outcomes and the role of high-sensitivity troponin T

BACKGROUND

The predictors of cardiovascular events in patients with chronic refractory angina are limited. High-sensitivity cardiac troponin T (hs-cTnT) assays are biomarkers that may be used to determine the prognosis of patients with stable coronary artery disease.

HYPOTHESIS

Hs-cTnT is a predictor of death and nonfatal myocardial infarction (MI) in patients with refractory angina.

METHODS

We prospectively enrolled 117 consecutive patients in this study. A heart team ruled out myocardial revascularization feasibility after assessing recent coronary angiograms; evidence of myocardial ischemia served as an inclusion criterion. Optimal medical therapy was encouraged via outpatient visits every 6 months; plasma hs-cTnT levels were determined at baseline. The primary endpoint was the composite incidence of death and nonfatal MI.

RESULTS

During a median follow-up period of 28.0 months (interquartile range, 18.0-47.5 months), an estimated 28.0-month cumulative event rate of 13.4% was determined via the Kaplan-Meier method. Univariate predictors of the composite endpoint were hs-cTnT levels and LV dysfunction. Following a multivariate analysis, only hs-cTnT was independently associated with the events in question, either as a continuous variable (hazard ratio per unit increase in the natural logarithm: 2.83, 95% confidence interval: 1.62-4.92, P < 0.001) or as a categorical variable (hazard ratio for concentrations above the 99th percentile: 5.14, 95% confidence interval: 2.05-12.91, P < 0.001).

CONCLUSIONS

In patients with chronic refractory angina, plasma concentration of hs-cTnT is the strongest predictor of death and nonfatal MI. Notably, none of the outcomes in question occurred in patients with baseline plasma levels <5.0 ng/L.

Epidemiology and pathogenesis of diffuse obstructive coronary artery disease: the role of arterial stiffness, shear stress, monocyte subsets and circulating microparticles

Despite falling age-adjusted mortality rates coronary artery disease (CAD) remains the leading cause of death worldwide. Advanced diffuse CAD is becoming an important entity of modern cardiology as more patients with historical revascularisation no longer have suitable anatomy for additional procedures. Advances in the treatment of diffuse obstructive CAD are hampered by a poor understanding of its development. Although the likelihood of developing clinically significant (obstructive) CAD is linked to traditional risk factors, the morphology of obstructive CAD among individuals is highly variable - some patients have diffuse stenotic disease, while others have a focal stenosis. This is challenging to explain in mechanistic terms as vascular endothelium is equally exposed to injury stimulants. Patients with diffuse disease are at high risk of adverse outcomes, particularly if unsuitable for revascularisation. We searched multiple electronic databases (MEDLINE, EMBASE and the Cochrane Database) and reviewed the epidemiology, pathogenesis and prognosis relating to advanced diffuse CAD with particular focus on the role of endothelial shear stress, large artery stiffness, monocyte subsets and circulating microparticles. Key messages Although traditional CAD risk factors correlate strongly with disease severity, significant individual variation in disease morphology exists. Advanced, diffuse CAD is difficult to treat effectively and can significantly impair quality of life and increases mortality. The pathophysiology associated with the progression of CAD is the result of complex maladaptive interaction between the endothelium, cells of the immune system and patterns of blood flow.

Treatment of Inoperable Coronary Disease and Refractory Angina: Spinal Stimulators, Epidurals, Gene Therapy, Transmyocardial Laser, and Counterpulsation

Intractable angina from refractory coronary disease is a severe form of myocardial ischemia for which revascularization provides no prognostic benefit. Inoperable coronary disease is also accompanied by a “vicious cycle” of myocardial dystrophy from a chronic alteration of the cardiac sympathetic tone and sensitization of damaged cardiac tissues. Several adjunctive treatments have demonstrated efficacy when revascularization is either unsuccessful or contraindicated. Spinal cord stimulation modifies the neurologic input and output of the heart by delivering a very low dose of electrical current to the dorsal columns of the high thoracic spinal cord. Neural fibers then release CGRP and other endogenous peptides to the coronary circulation reducing myocardial oxygen demand and enhancing vasodilation of collaterals to improve the myocardial blood flow of the most diseased regions of the heart. Randomized study has shown the survival data at five years is comparable to bypass for high-risk patients. Transmyocardial laser revascularization creates small channels into ischemic myocardium in an effort to enhance flow though studies have shown no improvement in prognosis over medical therapy alone. Enhanced external counterpulsation uses noninvasive pneumatic compression of the legs to improve diastolic filling of the coronary vessels and promote development of collateral flow. The compressor regimen requires thirty-five hours of therapy over a seven-week treatment period. Therapeutic angiogenesis requires injection of cytokines to promote neovascularization and improve myocardial perfusion into the regions affected by chronic ischemia. Phase 3 trials are pending. High thoracic epidural blockade produces a rapid and potent sympatholysis, coronary vasodilation and reduced myocardial oxygen demand in refractory coronary disease. This technique can be used as an adjunct to bypass surgery or medical therapy in chronic or acute unstable angina. Epidurals are easy to perform and often available for outpatient or inpatient use. The rapid anti-ischemic effect may complement therapeutic angiogenesis or other interventions with delayed onset to clinical benefit. A new era for interventional and implant cardiology is beginning to emerge as more clinicians, including cardiologists, gradually learn new procedures to safely provide more therapeutic options for patients suffering refractory angina.

Autologous CD34+ Cell Therapy for Refractory Angina: 2-Year Outcomes From the ACT34-CMI Study

An increasing number of patients have refractory angina despite optimal medical therapy and are without further revascularization options. Preclinical studies indicate that human CD34⁺ stem cells can stimulate new blood vessel formation in ischemic myocardium, improving perfusion and function. In ACT34-CMI (N = 167), patients treated with autologous CD34⁺ stem cells had improvements in angina and exercise time at 6 and 12 months compared to placebo; however, the longer-term effects of this treatment are unknown. ACT34 was a phase II randomized, double-blind, placebo-controlled clinical trial comparing placebo, low dose (1 × 10⁵ CD34/kg body weight), and high dose (5 × 10⁵ CD34/kg) using intramyocardial delivery into the ischemic zone following NOGA^® mapping. To obtain longer-term safety and efficacy in these patients, we compiled data of major adverse cardiac events (MACE; death, myocardial infarction, acute coronary syndrome, or heart failure hospitalization) up to 24 months as well as angina and quality of life assessments in patients who consented for 24-month follow-up. A total of 167 patients with class III-IV refractory angina were randomized and completed the injection procedure. The low-dose-treated patients had a significant reduction in angina frequency (p = 0.02, 0.035) and improvements in exercise tolerance testing (ETT) time (p = 0.014, 0.017) compared to the placebo group at 6 and 12 months. At 24 months, patients treated with both low-and high-dose CD34⁺ cells had significant reduction in angina frequency (p = 0.03). At 24 months, there were a total of seven deaths (12.5%) in the control group versus one (1.8%) in the low-dose and two (3.6%) in the high-dose (p = 0.08) groups. At 2 years, MACE occurred at a rate of 33.9%, 21.8%, and 16.2% in control, low-, and high-dose patients, respectively (p = 0.08). Autologous CD34⁺ cell therapy was associated with persistent improvement in angina at 2 years and a trend for reduction in mortality in no-option patients with refractory angina.

Predictors of long-term clinical endpoints in patients with refractory angina

Background

Clinical outcomes in patients with refractory angina (RA) are poorly characterized and variably described. Using the Duke Database for Cardiovascular Disease (DDCD), we explored characteristics that drive clinical endpoints in patients with class II to IV angina stabilized on medical therapy.

Methods and Results

We explored clinical endpoints and associated costs of patients who underwent catheterization at Duke University Medical Center from 1997 to 2010 for evaluation of coronary artery disease (CAD) and were found to have advanced CAD ineligible for additional revascularization, and were clinically stable for a minimum of 60 days. Of 77 257 cardiac catheterizations performed, 1908 patients met entry criteria. The 3‐year incidence of death; cardiac rehospitalization; and a composite of death, myocardial infarction, stroke, cardiac rehospitalization, and revascularization were 13.0%, 43.5%, and 52.2%, respectively. Predictors of mortality included age, ejection fraction (EF), low body mass index, multivessel CAD, low heart rate, diabetes, diastolic blood pressure, history of coronary artery bypass graft surgery, cigarette smoking, history of congestive heart failure (CHF), and race. Multivessel CAD, EF<45%, and history of CHF increased risk of mortality; angina class and prior revascularization did not. Total rehospitalization costs over a 3‐year period per patient were $10 185 (95% CI 8458, 11912) in 2012 US dollars.

Conclusions

Clinically stable patients with RA who are medically managed have a modest mortality, but a high incidence of hospitalization and resource use over 3 years. These findings point to the need for novel therapies aimed at symptom mitigation in this population and their potential impact on health care utilization and costs.

Transcatheter treatment for refractory angina with the Coronary Sinus Reducer

AIMS

To evaluate the clinical efficacy of the coronary sinus (CS) Reducer in attenuating angina severity in patients suffering from severe refractory angina.

METHODS AND RESULTS

Patients with refractory angina, objective evidence of myocardial ischaemia and no option for revascularisation were treated with CS Reducer implantation at two medical centres. Six-month follow-up evaluation consisted of clinical assessment of angina severity. Objective assessment of ischaemia at six-month follow-up was performed in one of the two centres. Successful CS Reducer implantation was achieved in 21 of 23 eligible patients, at both centres. No device-related adverse effects were observed during the procedure or the follow-up period. Canadian Cardiovascular Society (CCS) score diminished from a mean of 3.3 at baseline to 2.0 at six months (n=20, p<0.01), exercise duration was prolonged from 3:16 to 5:16 min (min:sec; n=8, p=0.05). Thallium SPECT summed stress score and summed difference score were both reduced (n=9, 21.5±10 vs.13.2±9, p=0.01, and 11.1±6 vs. 4.7±4, p=0.007, respectively). Wall motion score index at peak dobutamine infusion was also significantly improved (n=8, 1.9±0.4 vs. 1.4±0.4, p=0.046).

CONCLUSIONS

CS Reducer implantation was safe and resulted in significant improvement of angina class. The results of the ongoing randomised sham-control trial will address the concern regarding the possible placebo effect, and hopefully further support our encouraging observations.

Repetitive myocardial ischemia promotes coronary growth in the adult mammalian heart

BACKGROUND

Coronary artery disease and ischemic cardiomyopathy represent the leading cause of heart failure and continue to grow at exponential rates. Despite widespread availability of coronary bypass surgery and percutaneous coronary intervention, subsequent ischemic events and progression to heart failure continue to be common occurrences. Previous studies have shown that a subgroup of patients develop collateral blood vessels that serve to connect patent and occluded arteries and restore perfusion to ischemic territories. The presence of coronary collaterals has been correlated with improved clinical outcomes; however, the molecular mechanisms governing this process remain largely unknown.

METHODS AND RESULTS

To date, no mouse models of coronary arterial growth have been described. Using a closed-chest model of myocardial ischemia, we have demonstrated that brief episodes of repetitive ischemia are sufficient to promote the growth of both large coronary arteries and the microvasculature. Induction of large coronary artery and microvascular growth resulted in improvements in myocardial perfusion after prolonged ischemia and protected from subsequent myocardial infarction. We further show that repetitive ischemia did not lead to increased expression of classic proangiogenic factors but instead resulted in activation of the innate immune system and recruitment of macrophages to growing blood vessels.

CONCLUSIONS

These studies describe a novel model of coronary angiogenesis and implicate the cardiac macrophage as a potential mediator of ischemia-driven coronary growth.

Patients with coronary artery disease not amenable to traditional revascularization: prevalence and 3-year mortality

OBJECTIVES

To determine the contemporary prevalence of and mortality in patients with coronary artery disease (CAD) not amenable to revascularization.

BACKGROUND

A growing number of patients have severe CAD with ongoing angina despite optimal medical therapy which is not amenable to traditional revascularization. Limited data exist on contemporary prevalence and outcome for these patients.

METHODS

Clinical and angiographic data were reviewed for 493 consecutive patients undergoing coronary angiography and revascularization if indicated. Patients were categorized into six groups: (1) normal coronary arteries, (2) CAD <70%, (3) CAD >70% with complete revascularization by percutaneous intervention or coronary artery bypass grafting, (4) CAD >70% with partial revascularization, (5) CAD >70% treated medically, and (6) CAD >70% on optimal medical therapy with no revascularization option. All-cause mortality at 3 years was determined.

RESULTS

Prevalence for groups 1-6 was 14.8, 19.5, 36.9, 12.8, 9.3, and 6.7%, respectively. Three-year mortality increased with angiographic severity of CAD: 2.7, 6.3, 8.2, 12.7, 17.4, and 15.2%, respectively. Patients with incomplete revascularization (groups 4-6, n = 142) had higher mortality than completely revascularized patients (groups 1-3, n = 351): 14.8 vs. 6.6% (P = 0.004).

CONCLUSIONS

In a contemporary series of patients undergoing coronary angiography, 28.8% (142/493) of patients had significant CAD and did not undergo complete revascularization, including 12.8% partially revascularized, 9.3% managed medically, and 6.7% with "no-option." These patients had higher mortality at 3 years (14.8 vs. 6.6%, P = 0.004) when compared with completely revascularized patients.

Neurostimulation technology for the treatment of chronic pain: a focus on spinal cord stimulation

Over the past 40 years we have seen how electrical stimulation for the relief of pain has progressed from an experimental treatment based upon a clinical theory to being on the threshold of becoming a standard of medical practice. While tens of thousands of devices are implanted every year, the mechanism of action still evades complete understanding. Nevertheless, technological improvements have been considerable and the current neuromodulation devices are both extremely sophisticated and reliable. Unlike most conventional treatments, neurostimulation cannot be restricted to one speciality as its clinical applications ignore the boundaries of medical specialities. Conditions such as neuropathic pain in the back and the leg, complex regional pain syndrome, ischemic pain due to peripheral vascular disease and coronary artery disease are likely to respond to spinal cord stimulation. Even though the evidence for efficacy remains unsatisfactory, the stimulation of the dorsal column has been remarkably successful in relieving pain and improving function in patients who have failed conventional management. The development, the technicalities and the most important clinical applications of spinal cord stimulation are reviewed here.

Impact of External Counterpulsation Treatment on Emergency Department Visits and Hospitalizations in Refractory Angina Patients With Left Ventricular Dysfunction

Patients with refractory angina and left ventricular (LV) dysfunction exert an enormous burden on health care resources primarily because of the number of recurrent emergency department (ED) visits and hospitalizations. Enhanced external counterpulsation (EECP) therapy has emerged as a treatment option for patients with angina and LV dysfunction and has been shown to improve clinical outcomes and LV function. Improvements in symptoms and laboratory assessments in these patients, however, do not necessarily correlate with a reduction in ED visits and hospitalizations. This is the first study to assess the impact of EECP therapy on ED visits and hospitalization rates at 6-month follow-up. This prospective cohort study included 450 patients with LV dysfunction (ejection fraction <or=40%) treated with EECP therapy for refractory angina. Clinical outcomes, number of all-cause ED visits, and hospitalizations within the 6 months before EECP therapy were compared with those at 6-month follow-up. Despite the unfavorable risk profile, refractory angina patients with LV dysfunction achieved a substantial reduction in all-cause ED visits and hospitalization rates at 6-month follow-up. EECP therapy appears to offer an effective adjunctive treatment option for this group of patients.

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.

Spinal Cord Stimulation for Patients With Refractory Angina and Previous Coronary Surgery

BACKGROUND

Refractory angina pectoris is an exceptionally debilitating condition affecting patients who have typically failed multiple percutaneous and surgical revascularizations and optimal medical therapy and who are not amenable for further revascularization procedures. Spinal cord stimulation (SCS) has been adopted in this context at our institution and midterm mortality, anginal status, and quality of life have been evaluated.

METHODS

From 1998 to 2004, 51 patients with refractory class III-IV angina, who were not considered candidates for revascularization procedures, underwent SCS. All patients had already undergone previous surgical revascularization and a median of two percutaneous procedures. Transmyocardial laser revascularization had been previously performed in 8 cases (15.6%). Most of the patients (70.5%) had experienced a myocardial infarction. Mean ejection fraction was 0.42 +/- 0.121, Canadian Cardiovascular Society class 3.5 +/- 0.5, quality of life (Spitzer index) 4.5 +/- 1.2, and the median frequency of weekly angina episodes was 10.

RESULTS

There were no SCS implantation-related complications. At follow-up (100% complete, mean 24 +/- 18 months), a significant improvement of anginal symptoms (>50% reduction of weekly anginal episodes) occurred in 45 patients (88.2%). In those patients (Responders), the quality of life improved significantly (6.8 +/- 1.5; p < 0.0001), CCS class decreased to 2 +/- 0.7 (p < 0.0001), and the median frequency of weekly angina episodes to 3 (p < 0.0001). At 3 years, Responders' survival was 91.8 +/- 4.6% and the freedom from cardiac events 72.6 +/- 8.42%.

CONCLUSIONS

Spinal cord stimulation is a safe and effective procedure in truly no-option patients affected by refractory angina. A midterm sustained improvement of symptoms and quality of life have been documented with a satisfactory 3-year survival rate.

Regenerative medicine for cardiovascular disorders-new milestones: adult stem cells

Cardiovascular disorders are the leading causes of mortality and morbidity in the developed world. Cell-based modalities have received considerable scientific attention over the last decade for their potential use in this clinical arena. This review was intended as a brief overview on the subject of therapeutic potential of adult stem cells in cardiovascular medicine with basic science findings and the current status of clinical applications. The historical perspective and basic concepts are reviewed and a description of current applications and potential adverse effects in cardiovascular medicine is given. Future improvements on cell-based therapies will likely provide remarkable improvement in survival and quality of life for millions of patients with cardiovascular disorders.

A combination of omental flap and growth factor therapy induces arteriogenesis and increases myocardial perfusion in chronic myocardial ischemia: Evolving concept of biologic coronary artery bypass grafting

OBJECTIVE

The purpose of this study was to evaluate the therapeutic efficacy of the combined growth factor therapy with an omental flap in a rabbit model of chronic myocardial ischemia.

METHODS

Chronic ischemia was created in rabbits by placing a constrictor on the left circumflex artery. Four weeks later the animals were divided into 3 groups: group FG, in which a gelatin hydrogel sheet incorporating 100 microg of basic fibroblast growth factor was placed over the left circumflex region followed by covering with the omental flap including the intact gastroepiploic artery; group F, in which only the basic fibroblast growth factor sheet was placed; and group N, in which no treatment was done.

RESULTS

Cine magnetic resonance imaging analysis showed a greater percentage wall thickening in the left circumflex region in group FG than in other groups (group FG, 49.2% +/- 4.5%; group F, 41.2% +/- 3.8%; group N, 32.1% +/- 2.5%, P =.035, group FG vs group F). A colored microsphere assay showed higher perfusion in the left circumflex region in group FG than in group F. Perfusion in the left circumflex region was decreased after clamping the gastroepiploic artery pedicle in group FG (before clamping, 2.83 +/- 0.72 mL x min(-1) x g(-1); after clamping, 1.93 +/- 0.59 mL x min(-1) x g(-1); P < .01). In vivo angiography via gastroepiploic artery showed direct "to-and-fro" visible collaterals between the gastroepiploic and occluded left circumflex coronary arteries in group FG.

CONCLUSION

The combined growth factor therapy with an omental flap induced arteriogenesis and provided additional perfusion via the gastroepiploic artery to ameliorate regional dysfunction in the chronically ischemic myocardium.

Spinal cord stimulation for the management of refractory angina pectoris

Despite sophisticated medical and surgical procedures, including percutaneous endovascular methods, a large number of patients suffer from chronic refractory angina pectoris. Improvement of pain relief in this category of patients requires the use of adjuvant therapies, of which spinal cord stimulation (SCS) seems to be the most promising. Controlled studies suggest that in patients with chronic refractory angina, SCS provides symptomatic relief that is equivalent to that provided by surgical or endovascular reperfusion procedures, but with a lower rate of complications and rehospitalization. Similarly, SCS proved cost effective compared to medical as well as surgical or endovascular approaches in a comparable group of patients. This technique is still met with reluctance by the medical community. Reasons for this disinclination may be related to incomplete understanding of the mechanism of action of SCS and the fact that SCS refers to the modulation of neuroendocrine parameters rather than to revascularization, which is currently the dominant treatment paradigm in coronary artery disease.

Refractory myocardial ischemic syndromes: patients’ characterization and treatment goals

Experimental strategies such as gene transfer and/or cell transplantation have been explored to enrich collateral perfusion and improve contractility in severely ischemic cardiac patients. Nonetheless, the criteria used to define those patients are not uniform and need to be standardized. The authors propose herein standardized definitions in order to characterize the ‘no option’ ischemic cardiac patients as follows: lack of revascularization options; angina symptoms; limited exercise capacity; perfusion defects; an identifiable target myocardial region. In order to define a favorable clinical effect, the following end points should be the aim of treatment: improved exercise; reduced perfusion defects; improved angina or equivalent symptoms; augmented myocardial stress response; better quality of life parameters following treatment; improved collateral-dependent perfusion. The authors propose that such a systematic approach for patient evaluation should be considered to allow an accurate assessment of treatment efficacy and the comparison of results between alternative myocardial revascularization trials.

Treatment of refractory angina pectoris

Refractory angina pectoris is defined as Canadian Cardiovascular Society class III or IV angina, where there is marked limitation of ordinary physical activity or inability to perform ordinary physical activity without discomfort, with an objective evidence of myocardial ischemia and persistence of symptoms despite optimal medical therapy, life style modification treatments, and revascularization therapies. The patients with refractory angina pectoris may have diffuse coronary artery disease, multiple distal coronary stenoses, and or small coronary arteries. In addition, a substantial portion of these patients cannot achieve complete revascularization and continue to experience residual anginal symptoms that may impair quality of their life and increase morbidity. This represents an end-stage coronary artery disease characterized by a severe myocardial insufficiency usually with impaired left ventricular function. As the life expectancy is increasing, patients with angina pectoris refractory to conventional antianginal therapeutics are a challenging problem. We review the nonconventional therapies to treat the refractory angina pectoris, including pharmacotherapy, therapeutic angiogenesis, transcutaneus electrical nerve and spinal cord stimulation, enhanced external counterpulsation, surgical transmyocardial laser revascularization, percutaneous transmyocardial laser revascularization, percutaneous in situ coronary venous arterializations, and percutaneous in situ coronary artery bypass. These therapies are not supported by a large body of data and have only a complementary role; therefore, the aggressive traditional and proven treatment of angina pectoris should be continued along with these therapies, used on an individual basis.

Protein-, gene-, and cell-based therapeutic angiogenesis for the treatment of myocardial ischemia

Therapeutic angiogenesis aims at restoring perfusion to chronically ischemic myocardial territories by using growth factors or cells, without intervening on the epicardial coronary arteries. Despite angiogenesis having received considerable scientific attention over the last decade, it has not yet been shown to provide clinical benefit and is still reserved for patients who have failed conventional therapies. Nevertheless, angiogenesis is a very potent physiologic process involved in the growth and development of every animal and human, and it is likely that its use for therapeutic purposes, once its underlying mechanistic basis is better understood, will one day become an important modality for patients with CAD and other types of organ ischemia. This review summarizes current knowledge in therapeutic angiogenesis research.

Testing clinical therapeutic angiogenesis using basic fibroblast growth factor (FGF-2)

Therapeutic angiogenesis represents an attempt to relieve inadequate blood flow by the directed growth and proliferation of blood vessels. Neovascularization is a complex process involving multiple growth factors, receptors, extracellular matrix glycoproteins, intracellular and extracellular signaling pathways, and local and bone-marrow-derived constituent cells, all responding to a symphonic arrangement of temporal and spatial cues. In cardiovascular disease, patients with refractory angina and lower extremity intermittent claudication seem most amenable to early tests of therapeutic angiogenesis. Monotherapy with the recombinant protein basic fibroblast growth factor (FGF-2) has been tested in six human trials. These have shown provisional safety, and two have provided 'proof of concept' for the strategy of therapeutic angiogenesis. One large randomized phase II trial failed to show significant efficacy in coronary artery disease. Another showed significant efficacy in peripheral artery disease, although the magnitude of benefit was disappointing at the dose tested. This overview details the suitable clinical trial design and further steps toward the clinical development of FGF-2.

Transmyocardial Laser Therapy: A Strategic Approach

BACKGROUND

Coronary artery bypass and percutaneous intervention have become the established methods of coronary revascularization in treating angina pectoris. Subsets of angina patients, however, are not amenable to either of these procedures. Transmyocardial laser revascularization (TMR) has been developed as a potential treatment to address such patients, and clinical research to date illustrates the success of TMR for this patient group.

STRATEGIC PLAN SUMMARY

Although the symptoms of ischemic heart disease manifest themselves in a variety of ways, the best results with TMR are seen in patients with severe angina rather than in patients with silent ischemia or congestive heart failure. Potential TMR patients receive diagnostic tests to determine if and where the therapy should be applied. A recent cardiac catheterization is required to document the status of and the coronary-system suitability for the planned intervention. It is not appropriate to assume that a patient with nonbypassable, noninterventional coronary artery disease has to be relegated to medical therapy only. Additionally, echocardiography demonstrates the status of cardiac valves and segmental wall motion activity. This knowledge allows the surgeon to determine the sequence of surgery and if abnormalities are present. Once the decision to use TMR use has been made, there are 2 approaches--sole therapy or adjunctive therapy. TMR is not to be substituted for a feasible bypass graft, but the best time to make this decision may well be during the surgery itself, because grafts that appear surgically feasible on an angiogram may be less feasible after the chest has been opened. The decision to perform sole-therapy TMR in the absence of bypassable vessels clearly must be made before opening the chest. Whether to use cardiopulmonary bypass (CPB) and the sequence in which to perform TMR and bypass grafts are based on surgeon preference. The advantage of performing TMR on CPB is that channels can quickly be lased without pause. A potential advantage of performing TMR before bypass grafts is that "channel leak" (bleeding) can be minimized by the conclusion of the surgery. Complete revascularization has become technically more difficult because of the increasing use of percutaneous approaches and because patients are being referred for coronary artery bypass grafting much later in the course of their coronary disease progression than before. TMR may well be a viable alternative to bypassing a heavily diseased, previously intervened, small-diameter coronary artery. Thus, a model in which myocardial perfusion is considered within the context of the natural circulation can be conceived as an alternative to a model in which circulation is altered by interventional, surgical, and/or transmyocardial methods. TMR has been shown to be effective in accomplishing a complete revascularization when the restoration of circulation to ischemic territories with interventional therapy, bypass surgery, or a combination of both has been ineffective. We recommend that interested users follow this "complete revascularization strategy" algorithm for all ischemic vessels being considered for interventional or surgical treatment. Running each diseased vessel through this thought process will ensure that available treatment options are considered in the optimization of a patient's outcome.

CONCLUSION

The use of TMR for angina relief has evolved into a clinically proven technology that has enabled physicians to address difficult revascularization cases with a therapy that is safe and effective.

Management of refractory angina pectoris

An increasing number of patients with coronary artery disease have ischemie symptoms that are unresponsive to both conventional medical therapy and revascularization techniques. The objective of this study was to define the population of patients with refractory angina pectoris and to present the therapeutic options currently available for this condition. Among many techniques, the enhanced external counterpulsation, transmyocardial laser revascularization and neurostimulation have been shown to reduce angina and to improve objective measures of myocardial ischemia in patients with refractory angina.