Spinal cord stimulation for refractory angina pectoris: a retrospective analysis of efficacy and cost-benefit

Neuromodulation in patients with refractory angina pectoris: a review

The number of patients with coronary artery disease (CAD) who have persisting angina pectoris despite optimal medical treatment known as refractory angina pectoris (RAP) is growing. Current estimates indicate that 5-10% of patients with stable CAD have RAP. In absolute numbers, there are 50 000-100 000 new cases of RAP each year in the USA and 30 000-50 000 new cases each year in Europe. The term RAP was formulated in 2002. RAP is defined as a chronic disease (more than 3 months) characterized by diffuse CAD in the presence of proven ischaemia which is not amendable to a combination of medical therapy, angioplasty, or coronary bypass surgery. There are currently few treatment options for patients with RAP. One such last-resort treatment option is spinal cord stimulation (SCS) with a Class of recommendation IIB, level of evidence B in the 2019 European Society of Cardiology guidelines for the diagnosis and management of chronic coronary syndromes. The aim of this review is to give an overview of neuromodulation as treatment modality for patients with RAP. A comprehensive overview is given on the history, proposed mechanism of action, safety, efficacy, and current use of SCS.

Cost-effectiveness of the coronary sinus Reducer and its impact on the healthcare burden of refractory angina patients

AIMS

The coronary sinus Reducer is a percutaneous device proven to improve angina symptoms in refractory angina (RA). We evaluated its potential cost-effectiveness and impact on the healthcare resource use.

METHODS AND RESULTS

Angina-related healthcare resource usage and quality-of-life data were collected for 215 consecutive RA patients undergoing Reducer implantation in Belgium, the Netherlands, and Italy. Costs were assessed from each country's healthcare system perspective. Data from the date of RA diagnosis to Reducer implantation [Standard-of-Care (SoC)-period] and from Reducer implantation to follow-up (Reducer-period) were compared: during Reducer-period, a significant reduction in angina-driven hospitalizations, outpatient visits, coronary angiograms, and percutaneous coronary interventions per patient-year was observed, translating into significantly reduced costs per patient-year. To assess cost-effectiveness, costs and utilities of 1-year SoC were compared with those of 1-year Reducer-period. Assumptions on Reducer efficacy duration were further explored with modelled projections. Reducer was associated with higher quality-adjusted life years (QALYs: 0.665 vs. 0.580, P < 0.001) and incremental costs, yielding incremental cost-effectiveness ratios (ICERs) of 53 197, 34 948, 63 146 €/QALY gained in Belgium, the Netherlands, and Italy, respectively. Under both the assumptions of 2 and 3 years Reducer effect duration with a 30%-year efficacy decrease, the device yielded ICERs in the range of 1977-20 796 €/QALY gained.

CONCLUSION

In patients with RA, Reducer device decreases healthcare resource use and related costs. In a limited 1-year timeframe, Reducer is consistently cost-effective according to a range of cost-effectiveness thresholds. Under the explored assumptions, the device yields cost-effectiveness ratios suggesting high value from all the considered perspectives.

An evidence-based review of neuromodulation for the treatment and management of refractory angina

Angina pectoris is defined as substernal chest pain that is typically exacerbated by exertion, stress, or other exposures. There are various methods of treatment for angina. Lifestyle modification and pharmacological management are considered as conservative treatments. If these medications do not result in the resolution of pain, more invasive approaches are an option, like coronary revascularization. Refractory angina (RA) is differentiated from acute or chronic angina based on the persistence of symptoms despite conventional therapies. Overall, the prevalence of RA is estimated to be 5%-15% in patients with coronary artery disease, which can account for up to 1,500,000 current cases and 100,000 new cases in the United States per year. Spinal cord stimulation treatment is a viable option for patients who are suffering from RA pain and are either not candidates for revascularization surgery or are currently not being well managed on more traditional treatments. Many studies show a positive result.

Interventional treatment of pain in refractory angina. A review

BACKGROUND

Refractory angina is characterized by repeated attacks of chest pain in patients on maximal anti-anginal pharmacotherapy, with a professional conscensus that further surgical or radiological revascularization would be futile. Refractory angina is a serious but relatively uncommon health problem, with a reported incidence of approximately 30 patients per million people/year. In this condition simply treating the associated pain alone is important as this can improve exercise tolerance and quality of life.

METHODS

An extensive literature search using five different medical databases was performed and from this, eighty-three papers were considered appropriate to include within this review.

RESULTS AND CONCLUSION

Available literature highlights several methods of interventional pain treatment, including spinal cord stimulation and video-assisted upper thoracic sympathectomy which can provide good analgesia whilst improving physical activities and quality of life. The positive effect of spinal cord stimulation on the intensity of pain and quality of life has been confirmed in nine randomized controlled trials. Other potential treatment methods include stellate ganglion blocks, insertion of thoracic epidural or spinal catheters and transcutaneous electrical nerve stimulation. These approaches however appear more useful for diagnostic purposes and perhaps as short-term treatment measures.

Neural mechanisms of spinal cord stimulation

Neuromodulation, specifically spinal cord stimulation (SCS), relieves pain and improves organ function. This chapter discusses the limited information presently available about the underlying mechanisms that explain the beneficial effects of treating patients with SCS. Where applicable, information is presented about translational research that illustrates the importance of collaboration between clinicians, basic scientists, and engineers. This chapter presents the infant stage of studies that attempt to explain the mechanisms which come into play for treating neuropathic pain, ischemic pain in peripheral vascular disease, and diseases of the visceral organs, specifically the gastrointestinal tract and the heart. The basic science studies will demonstrate how SCS acts on various pain syndromes and diseases via multiple pathways in the central nervous system as well as in somatic structures and visceral organs.

Hospital utilization and costs for spinal cord stimulation compared with enhanced external counterpulsation for refractory angina pectoris

RATIONALE, AIMS AND OBJECTIVES

The aim of this study was to compare acute hospital utilization and costs for patients with refractory angina pectoris undergoing spinal cord stimulation (SCS) versus enhanced external counterpulsation (EECP).

METHOD

Seventy-three persons were included in this register study. The acute hospital utilization and costs for SCS and EECP were followed over a period from 12 months before treatment to 24 months after treatment using Patient Administrative Support in Skåne for publicly organized care.

RESULTS

SCS was significantly more expensive than EECP (P < 0.001). Both SCS and EECP entailed fewer days of hospitalization for coronary artery disease in the 12-month follow-up compared with the 12 months preceding treatment. Patients treated with EECP showed an association between reduced hospital admissions and an improved Canadian Cardiovascular Society classification class compared with 1 year before treatment. A significant reduction in cost was seen in both the SCS group (P = 0.018 and P = 0.001, respectively) and the EECP group (P = 0.002 and P = 0.045, respectively) during 12 and 24 months of follow-up compared with before treatment. There were no significant differences between the groups for hospitalization days or admissions, including costs, at the different follow-ups.

CONCLUSIONS

Cost-effective treatment modalities such as SCS and EECP are valuable additions to medical and revascularization therapy in patients with refractory angina pectoris. Pre-existing conditions and the patient's preferences should be taken in consideration when clinicians choose between treatments for this group of patients.

Spinal cord stimulation in pain management: a review

Spinal cord stimulation has become a widely used and efficient alternative for the management of refractory chronic pain that is unresponsive to conservative therapies. Technological improvements have been considerable and the current neuromodulation devices are both extremely sophisticated and reliable in obtaining good results for various clinical situations of chronic pain, such as failed back surgery syndrome, complex regional pain syndrome, ischemic and coronary artery disease. This technique is likely to possess a savings in costs compared with alternative therapy strategies despite its high initial cost. Spinal cord stimulation continues to be a valuable tool in the treatment of chronic disabling pain.

Technological innovation in spinal cord stimulation: use of a newly developed delivery device for introduction of spinal cord stimulation leads

OBJECTIVE

The use of multiple cylindrical leads and multicolumn and single column paddle leads in spinal cord stimulation offers many advantages over the use of a single cylindrical lead. Despite these advantages, placement of multiple cylindrical leads or a paddle lead requires a more invasive surgical procedure. Thus, the ideal situation for lead delivery would be percutaneous insertion of a paddle lead or multiple cylindrical leads. This study evaluated the feasibility and safety of percutaneous delivery of S-Series paddle leads using a new delivery device called the Epiducer lead delivery system (all St. Jude Medical Neuromodulation Division, Plano, TX, USA).

MATERIALS AND METHODS

This uncontrolled, open-label, prospective, two-center study approved by the AZ St. Lucas (Ghent) Ethics Committee evaluated procedural aspects of implantation of an S-Series paddle lead using the Epiducer lead delivery system and any adverse events relating to the device. Efficacy data during the patent's 30-day trial also were collected.

RESULTS

  Data from 34 patients were collected from two investigational sites. There were no adverse events related to the Epiducer lead delivery system. The device was inserted at an angle of either 20°-30° or 30°-40° and was entered into the epidural space at T12/L1 in most patients. The S-Series paddle lead was advanced four vertebral segments in more than 50% of patients. The average (±standard deviation [SD]) time it took to place the Epiducer lead delivery system was 8.7 (±5.0) min. The average (+SD) patient-reported pain relief was 78.8% (+24.1%).

CONCLUSIONS

This study suggests the safe use of the Epiducer lead delivery system for percutaneous implantation and advancement of the S-Series paddle lead in 34 patients.

Spinal cord stimulation for refractory angina pectoris -a case report-

Refractory angina pectoris is defined as angina refractory to optimal medical treatment and standard coronary revascularization procedures. Despite recent therapeutic advances, patients with refractory angina pectoris are not adequately treated. Spinal cord stimulation is a minimally invasive and reversible technique which utilizes electrical neuromodulation by means of an electrode implanted in the epidural space. It has been reported to be an effective and safe treatment for refractory angina pectoris. We report a case of spinal cord stimulation which has effectively relieved chest pain due to coronary artery disease in a 40-year-old man. This is the first report of spinal cord stimulation for treatment of refractory angina pectoris in South Korea.

Spinal cord stimulation for long-term treatment of severe angina pectoris: what does the evidence say?

Patients who continue to suffer from severe and disabling angina pectoris, despite optimum treatment in terms of conventional pharmacological therapy and/or revascularization procedures, have been termed as having refractory angina pectoris. The future group of patients with refractory angina pectoris will be different from today’s patients and represent a ‘moving target’ as risk factors, efficacy of treatment and indications continue to change. Spinal cord stimulation (SCS) is today considered as first-line treatment of refractory angina pectoris, by the European Society of Cardiology, with an anti-ischemic effect. There is strong evidence for SCS giving symptomatic benefits (decrease in anginal attacks), improved quality of life and improvement of functional status. In addition, SCS seems to be cost effective with a ‘break-even’ after approximately 15–16 months.

Clinical and cost-effectiveness analysis of an open label, single-centre, randomised trial of spinal cord stimulation (SCS) versus percutaneous myocardial laser revascularisation (PMR) in patients with refractory angina pectoris: The SPiRiT trial

Background

Patients with refractory angina have significant morbidity. This study aimed to compare two of the treatment options, Spinal Cord Stimulation (SCS) and Percutaneous Myocardial Laser Revascularisation (PMR) in terms of clinical outcomes and cost-effectiveness.

Methods

Eligible patients were randomised to PMR or SCS and followed up for exercise tolerance time (ETT), Canadian Cardiovascular Society (CCS) classification and the quality of life measures SF-36, Seattle Angina Questionnaire and the EuroQoL at 3, 12 and 24 months. Utilities were calculated using the EQ-5D and these and costs were compared between groups. The incremental cost-effectiveness ratio (ICER) per QALY for SCS compared to PMR was also calculated.

Results

At 24 months post-randomisation, patients that had SCS and PMR had similar ETT (mean difference 0.05, 95% CI -2.08, 2.18, p = 0.96) and there was no difference in CCS classification or quality of life outcomes. The difference in overall mean costs when comparing SCS to PMR was GBP5,520 (95% CI GBP1,966 to GBP8,613; p < 0.01) and the ICER of using SCS was GBP46,000 per QALY.

Conclusion

Outcomes after SCS did not differ appreciably from those after PMR, with the former procedure being less cost-effective as currently applied. Larger studies could clarify which patients would most benefit from SCS, potentially increasing cost-effectiveness.

Trial registration

Current Controlled Trials ISRCTN09648950

Putative mechanisms behind effects of spinal cord stimulation on vascular diseases: a review of experimental studies

Spinal cord stimulation (SCS) is a widely used clinical technique to treat ischemic pain in peripheral, cardiac and cerebral vascular diseases. The use of this treatment advanced rapidly during the late 80's and 90's, particularly in Europe. Although the clinical benefits of SCS are clear and the success rate remains high, the mechanisms are not yet completely understood. SCS at lumbar spinal segments (L2-L3) produces vasodilation in the lower limbs and feet which is mediated by antidromic activation of sensory fibers and decreased sympathetic outflow. SCS at thoracic spinal segments (T1-T2) induces several benefits including pain relief, reduction in both frequency and severity of angina attacks, and reduced short-acting nitrate intake. The benefits to the heart are not likely due to an increase, or redistribution of local blood flow, rather, they are associated with SCS-induced myocardial protection and normalization of the intrinsic cardiac nervous system. At somewhat lower cervical levels (C3-C6), SCS induces increased blood flow in the upper extremities. SCS at the upper cervical spinal segments (C1-C2) increased cerebral blood flow, which is associated with a decrease in sympathetic activity, an increase in vasomotor center activity and a release of neurohumoral factors. This review will summarize the basic science studies that have contributed to our understanding about mechanisms through which SCS produces beneficial effects when used in the treatment of vascular diseases. Furthermore, this review will particularly focus on the antidromic mechanisms of SCS-induced vasodilation in the lower limbs and feet.

Spinal cord stimulation for refractory chronic angina pectoris: influence on quality of life

Percutaneous coronary revascularization, coronary artery bypass graft surgery and medical management are nowadays very effective in treating coronary artery disease. Nevertheless, the number of patients affected by refractory chronic angina pectoris is increasing. Epidemiological estimates for refractory angina pectoris predict the diagnosis of more than 100,000 patients each year in the USA and approximately 50,000 in Europe. Spinal cord stimulation is a valuable therapeutic option for patients who have failed multiple percutaneous and surgical revascularizations and who are not eligible for further revascularization procedures. The aim of this study is to assess the benefits, in terms of quality of life, of spinal cord stimulation in no-option patients affected by refractory angina pectoris.

Management of chronic severe pain: spinal neuromodulatory and neuroablative approaches

The spinal cord is the target of many neurosurgical procedures used to treat pain. Compactness and well-defined tract separation in addition to well understood dermatomal cord organization make the spinal cord an ideal target for pain procedures. Moreover, the presence of opioid and other receptors involved in pain modulation at the level of the dorsal horn increases the suitability of the spinal cord. Neuromodulative approaches of the spinal cord are either electrical or pharmacological. Electrical spinal cord modulation is used on a large scale for various pain syndromes including; failed back surgery syndrome (FBSS), complex regional pain syndrome (CRPS), neuropathic pain, angina, and ischemic limb pain. Intraspinal delivery of medications e.g. opioids is used to treat nociceptive and neuropathic pains due to malignant and cancer pain etiologies. Neuroablation of the spinal cord pain pathway is mainly used to treat cancer pain. Targets involved include; the spinothalamic tract, the midline dorsal column visceral pain pathway and the trigeminal tract in the upper spinal cord. Spinal neuroablation can also involve cellular elements such as with trigeminal nucleotomy and the dorsal root entry zone (DREZ) operation. The DREZ operation is indicated for phantom type pain and root avulsion injuries. Due to its reversible nature spinal neuromodulation prevails, and spinal neuroablation is performed in a few select cases.

Spinal cord stimulation for ischemic heart disease and peripheral vascular disease

Ischemic disease (ID) is now an important indication for electrical neuromodulation (NM), particularly in chronic pain conditions. NM is defined as a therapeutic modality that aims to restore functions of the nervous system or modulate neural structures involved in the dysfunction of organ systems. One of the NM methods used is chronic electrical stimulation of the spinal cord (spinal cord stimulation: SCS). SCS in ID, as applied to ischemic heart disease (IHD) and peripheral vascular disease (PVD), started in Europe in the 1970s and 1980s, respectively. Patients with ID are eligible for SCS when they experience disabling pain, resulting from ischaemia. This pain should be considered therapeutically refractory to standard treatment intended to decrease metabolic demand or following revascularization procedures. Several studies have demonstrated the beneficial effect of SCS on IHD and PVD by improving the quality of life of this group of severely disabled patients, without adversely influencing mortality and morbidity. SCS used as additional treatment for IHD reduces angina pectoris (AP) in its frequency and intensity, increases exercise capacity, and does not seem to mask the warning signs of a myocardial infarction. Besides the analgesic effect, different studies have demonstrated an anti-ischemic effect, as expressed by different cardiac indices such as exercise duration, ambulatory ECG recording, coronary flow measurements, and PET scans. SCS can be considered as an alternative to open heart bypass grafting (CABG) for patients at high risk from surgical procedures. Moreover, SCS appears to be more efficacious than transcutaneous electrical nerve stimulation (TENS). The SCS implantation technique is relatively simple: implanting an epidural electrode under local anesthesia (supervised by the anesthesist) with the tip at T1, covering the painful area with paraesthesia by external stimulation (pulse width 210, rate 85 Hz), and connecting this electrode to a subcutaneously implanted pulse generator. In PVD the pain may manifest itself at rest or during walking (claudication), disabling the patient severely. Most of the patients suffer from atherosclerotic critical limb ischemia. All patients should be therapeutically refractory (medication and revascularization) to become eligible for SCS. Ulcers on the extremities should be minimal. In PVD the same implantation technique is used as in IHD except that the tip of the electrode is positioned at T10-11. In PVD the majority of the patients show significant reduction in pain and more than half of the patients show improvement of circulatory indices, as shown by Doppler, thermography, and oximetry studies. Limb salvage studies show variable results depending on the stage of the trophic changes. The underlying mechanisms of action of SCS in PVD require further elucidation.

Spinal cord stimulation: indications and outcomes

✓Spinal cord stimulation (SCS) is the most commonly used implantable neurostimulation modality for management of pain syndromes. In this paper the authors describe the current indications for SCS and its efficacy in the treatment of those diseases. Specifically, the literature on patient selection and outcomes after SCS for failed–back surgery syndrome (FBSS), refractory angina pectoris, peripheral vascular disease, and complex regional pain syndrome (CRPS) Type I was reviewed. Effective pain relief was obtained in 60 to 80% of patients with FBSS and CRPS Type I. Furthermore, these patients had significant improvements in quality of life (QOL) and a significantly greater chance of returning to work than patients who did not undergo SCS. The use of SCS in patients with inoperable angina (that is, refractory angina pectoris) resulted in significant decreases in chest pain and hospital admissions as well as increased exercise duration, with less morbidity than with open procedures that were performed for pain control only. Patients with inoperable PVD also demonstrated significant improvements in pain relief, QOL, and limb mobility. Reported complications were mostly related to hardware and were relatively minor. Review of randomized controlled studies supports the use of SCS as an effective treatment modality for pain associated with FBSS, refractory angina pectoris, peripheral vascular disease, and CRPS Type I.

The sustained benefits of long-term neurostimulation in patients with refractory chest pain and normal coronary arteries

OBJECTIVES

To assess the long-term efficacy of neurostimulation for treating refractory angina pectoris-like chest pain, we followed patients, treated with either transcutaneous electrical nerve stimulation (TENS) or spinal cord stimulation (SCS).

METHODS

Neurostimulation was judged successful and subsequently continued when initial pain was reduced at least 50%. All patients started with TENS, but if skin irritation occurred during TENS, a SCS system was implanted. The quality of life was measured at baseline and follow-up with the Seattle Angina Questionnaire. Additional information was gathered concerning anti-anginal medication, complaints, and physical condition.

RESULTS

Of 36 patients treated successfully with neurostimulation, we identified 24 patients after a mean (SD) follow-up period of 5.08 (3.86) years; 12 patients dropped out of the study. In 13 of the remaining 24 patients, TENS induced skin irritation. Eight of these 13 patients received successful SCS, while five refused implantation. In the 24 patients, a mean pain reduction of 57% was achieved in conjunction with an increased exercise capacity of 30% and walking distance increased from 0.73 (0.83) to 1.62 (1.62) (p=0.018). Within the Seattle Angina Questionnaire the domain 'disease perception' improved from 38.89 (16.61) to 49.31 (21.83) (p=0.004), the domain 'physical limitation' improved from 29.89 (15.10) to 40.97 (22.63) (p=0.001) and 'anginal frequency' improved from 41.67 (24.08) to 55.00 (23.03) (p=0.005). In addition, nitroglycerin consumption was reduced from 7.85 (8.49) to 1.98 (2.19) (p=0.001).

CONCLUSION

Neurostimulation techniques should thus be of widespread value for treating angina pectoris-like chest pain in patients who are refractory to medication.

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.

An open label, single-centre, randomized trial of spinal cord stimulation vs. percutaneous myocardial laser revascularization in patients with refractory angina pectoris: the SPiRiT trial

AIMS

Refractory angina pectoris leads to significant morbidity. Treatment options include percutaneous myocardial laser revascularization (PMR) and spinal cord stimulation (SCS). This study was designed to compare these two treatments.

METHODS AND RESULTS

Subjects with Canadian Cardiovascular Society (CCS) class 3/4 angina and reversible perfusion defects were randomized to SCS (34) or PMR (34). The primary outcome was to compare exercise treadmill time on a modified Bruce protocol over 12 months. Thirty subjects in both groups completed 12-month follow-up. The mean total exercise time was 6.38 +/- 3.45 min in the SCS group and 7.41+/-3.68 min in the PMR group at baseline and 7.08 +/- 0.67 min in the SCS group and 7.12 +/-0.71 min in the PMR group at 12 months (95% confidence limits for the difference between the groups -1.02 to + 2.2 min, P = 0.466). There were no differences in angina-free exercise capacity, CCS class, and quality of life between treatments. SCS patients had more adverse events in the first 12 months, mainly angina or SCS system related (P = 0.001).

CONCLUSION

There was little evidence of a difference in effectiveness between SCS and PMR in patients with refractory angina.

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.