Coronary Sinus Reducer Implantation for the Treatment of Chronic Refractory Angina

The Coronary Sinus Reducer Stent for the Treatment of Refractory Angina Pectoris: From the Conception of Innovation to Clinical Application

The Neovasc Coronary Sinus Reducer Stent (CSRS) was developed for the treatment of patients who continue to suffer from disabling symptoms despite optimal medical therapy. This patient population with refractory angina symptoms is expected to grow, since life expectancy of individuals with atherosclerotic coronary artery disease is increasing. In this paper, we discussed the development of a novel device the CSRS and the upside-down strategy to rebuild a retrograde coronary pressure that was attenuated by the atherosclerotic disease.

[Coronary sinus reducer : Technical aspects, prevention and management of potential complications]

Coronary sinus reducer implantation is a percutaneous technique creating a narrowing in the coronary sinus through the implantation of an hourglass-shaped endoprosthesis. It is proposed to reduce symptoms in patients suffering from refractory angina pectoris. This innovative treatment is experiencing a major craze among interventional cardiologists. It is associated with very high procedural success rates. Complications are rare and include coronary sinus dissection or perforation and migration of the device. This review exposes the device implantation technique, the potential anatomical difficulties, the tips and tricks to overcome challenging situations. It also focuses on the prevention and management of potential complications.

Safety and Effectiveness of Coronary Sinus Reducer in the Therapy of Refractory Angina Pectoris-Mid-Term Results of the Real-Life Cohort

Background: Despite continuous improvements in revascularization techniques, refractory angina without potential revascularization options remains a relevant clinical issue with significant impact on the patient's quality of life. Recently, a novel device, the Coronary Sinus Reducer (CSR), has been introduced into clinical practice as a therapeutic option for patients with disabling angina pectoris. In this single-center, observational study, we evaluated the mid-term (3-month) safety and efficacy of the CSR in a real-world cohort. Methods: The study population consisted of 55 patients with refractory angina without potential revascularization options, who were predominantly men (87.3%) with a high cardiovascular risk factor burden and advanced angina (baseline CCS angina class 3.15 ± 0.6). In terms of procedure safety, all patients underwent successful device deployment with only one periprocedural complication. Results: At the 3-month follow-up, we observed a statistically significant improvement in angina control measured CCS class and SAQ-7 total questionnaire along with increased abolition of physical limitation-6-MWT (233.3 ± 107.1 vs. 305.2 ± 126.8; p < 0.0001). Additionally, we observed significant improvement in terms of quality of life measurements SF-36, the EQ-5D-5L questionnaire, and the EQ-VAS. Conclusions: Our real-world data suggest that CSR implantation is a relatively safe procedure and appears to be particularly effective in relieving angina symptoms and improving quality of life in subjects with refractory angina.

Mechanisms of coronary sinus reducer for treatment of myocardial ischemia: in silico study

The coronary sinus reducer (CSR) is an emerging medical device for treating patients with refractory angina, often associated with myocardial ischemia. Patients implanted with CSR have shown positive outcomes, but the underlying mechanisms are unclear. This study sought to understand the mechanisms of CSR by investigating its effects on coronary microcirculation hemodynamics that may help explain the therapy's efficacy. We applied a validated computer model of the coronary microcirculation to investigate how CSR affects hemodynamics under different degrees of coronary artery stenosis. With moderate coronary stenosis, an increase in capillary transit time (CTT) [up to 69% with near-complete coronary sinus (CS) occlusion] is the key change associated with CSR. Because capillaries in the microcirculation can still receive oxygenated blood from the upstream artery with moderate stenosis, the increase in CTT allows more time for the exchange of gases and nutrients, aiding tissue oxygenation. With severe coronary stenosis; however, the redistribution of blood draining from the nonischemic region to the ischemic region (up to 96% with near-complete CS occlusion) and the reduction in capillary flow heterogeneity are the key changes associated with CSR. Because blood draining from the nonischemic region is not completely devoid of O2, the redistribution of blood to the capillaries in the ischemic region by CSR is beneficial especially when little or no oxygenated blood reaches these capillaries. This simulation study provides insights into the mechanisms of CSR in improving clinical symptoms. The mechanisms differ with the severity of the upstream stenosis.NEW & NOTEWORTHY Emerging coronary venous retroperfusion treatments, particularly coronary sinus reducer (CSR) for refractory angina linked to myocardial ischemia, show promise; however, their mechanisms of action are not well understood. We find that CSR's effectiveness varies with the severity of coronary stenosis. In moderate stenosis, CSR improves tissue oxygenation by increasing capillary transit time, whereas in severe stenosis, it redistributes blood from nonischemic to ischemic regions and reduces capillary flow heterogeneity.

Coronary sinus narrowing therapy: A "Reducer" for angina and beyond

Refractory Angina (RA) is an increasingly common clinical diagnosis, in which patients unsuitable for further percutaneous or surgical procedures experience anginal symptoms, despite receiving optimal medical therapy. This clinical condition challenges the everyday activities and diminishes the quality of life of these patients. A wide variety of novel therapies for this type of angina are being investigated for clinical use. One of them is coronary sinus narrowing, which is performed as a percutaneous interventional procedure using catheter-delivered device, the Reducer. The device is implanted in the coronary sinus creating a physical narrowing and a pressure gradient in the sinus. This intervention improves the impaired blood flow in the ischemic regions of the heart leading to the relief of the anginal symptoms and, therefore, the overall clinical improvement of these patients. Several clinical trials have established both the safety and efficacy of the coronary sinus Reducer, while ongoing trials are aiming to further establish the procedure's safety and efficiency in both RA and other cardiovascular diseases, such as coronary microvascular dysfunction. This review aims to discuss the pathophysiology and the role of the coronary sinus Reducer in RA, the clinical trials documenting its safety and efficacy, as well as the future perspectives of this procedure among cardiovascular diseases.

[Coronary sinus reducer : Literature review and issues surrounding the France Reducer registry]

Coronary sinus Reducer implantation is a percutaneous technique used to treat patients suffering from refractory angina pectoris. The device narrows the coronary sinus, increases the back pressure in the myocardial venous system and forces redistribution of coronary blood flow from less ischemic subepicardium to the more ischemic subendocardium. Multiple clinical studies had proven its efficacy to alleviate myocardial ischemia and related symptoms, and to improve the quality of life of patients with refractory symptomatic chronic coronary artery disease for whom coronary revascularization is deemed unsuitable. This literature review aims to expose the device design, its mechanisms of action, and the clinical data supporting its use. Since November 2021 Reducer's reimbursement has been granted in France by the national health authority. It is the first device to be approved under a newly established reimbursement approval process. A transitional coverage is provided with opportunities for renewal before applying for full-time reimbursement. To fulfill the requirements of the National Commission for Evaluation of Medical Devices and Health Technologies, the French Society of Cardiology has been creating the France Reducer registry. This clinical registry has been collecting data from patients undergoing coronary sinus Reducer implantation regarding their clinical situation, periprocedural information, and one-year follow-up. It is crucial for the future of this emerging therapeutic option in France. To date, 215 patients from 28 centers have been included between June 2022 and September 2023.

Refractory angina pectoris: a 20-year (2003-2022) bibliometric analysis

Background

The increasing number of patients with refractory angina pectoris, combined with the aging population and improved survival rates among coronary heart disease patients, presents a significant challenge in contemporary cardiovascular medicine. The treatment of refractory angina has been an ongoing area of exploration, yet a comprehensive analysis of the existing literature on this topic is currently lacking. Therefore, this study aims to provide the first bibliometric analysis of publications related to refractory angina.

Methods

A systematic search was conducted in the Web of Science database to identify articles related to refractory angina published between 2003 and 2022. The inclusion criteria were limited to articles and reviews written in English. CiteSpace software was utilized to conduct a collaborative network analysis of countries/regions, institutions and authors, co-occurrence analysis of keywords, and co-citation analysis of authors and references.

Results

A total of 1,386 publications were identified, with an annual publication volume exhibiting fluctuation over time. American and European countries and institutions demonstrated a leading position in terms of research output. Henry TD emerged as the most prolific researcher in the field, while Mannheimer C received the highest number of citations. The primary research hotspot within this field focused on the treatment of refractory angina, with recent emphasis on emerging treatments such as stem cell therapy and the coronary sinus reducer. A significant number of clinical trials have been conducted, with a continuous focus on patient benefits, quality of life, and survival prognosis.

Conclusion

Significant progress has been made in the field of refractory angina pectoris in recent years. Novel treatment methods, including spinal cord stimulation, enhanced external counterpulsation, stem cell therapy, and the coronary sinus reducer, hold promising therapeutic prospects. However, further high-quality evidence-based research is essential to support these emerging interventions. Additionally, the development of comprehensive evidence-based guidelines for refractory angina treatment is crucial. Such guidelines would provide clinicians with a framework to navigate the complexities of treatment choices and optimize patient care in this challenging condition.

INOCA/ANOCA: Mechanisms and novel treatments

Angina or ischemia with no obstructive coronary disease (ANOCA/INOCA) is a common but under-treated condition due to poorly understood pathophysiologic mechanisms, limited diagnostic tools, and lack of proven targeted therapy. Coronary microvascular dysfunction (CMD) occurs when the microvasculature inadequately perfuses the myocardium under stress, or at rest in the case of microvascular spasm resulting in ANOCA/INOCA. Coronary functional angiography (CFA) measures endothelial independent microvascular dysfunction (coronary flow reduction <2.5) in response to adenosine and endothelial dependent microvascular dysfunction (lack of dilation and/or constriction) to acetylcholine testing as well as epicardial and microvascular spasm. Current treatment for coronary microvascular dysfunction is limited to renin-angiotensin system (RAS) inhibitors and statins as well as antianginal medications. Novel therapies targeting the underlying pathology are under development and include the coronary sinus reducer, CD34+ stem cell therapy, and novel pharmacologic agents such as sGC stimulators or endothelin-receptor blockers. We review the current understanding of pathophysiology, diagnostic tools, and novel therapies for coronary microvascular dysfunction in ANOCA/INOCA.

Effect of Coronary Sinus Reducer Implantation on Aerobic Exercise Capacity in Refractory Angina Patients-A CROSSROAD Study

Coronary sinus reducer (CSR) implantation is a new treatment option for patients with refractory angina pectoris. However, there is no evidence from a randomized trial that would show an improvement in exercise capacity after this treatment. The aim of this study was to evaluate the influence of CSR treatment on maximal oxygen consumption and compare it to a sham procedure. Twenty-five patients with refractory angina pectoris (Canadian Cardiovascular Society (CCS) class II-IV) were randomized to a CSR implantation (n = 13) or a sham procedure (n = 12). At baseline and after 6 months of follow-up, the patients underwent symptom-limited cardiopulmonary exercise testing with an adjusted ramp protocol and assessment of angina pectoris using the CCS scale and Seattle angina pectoris questionnaire (SAQ). In the CSR group, maximal oxygen consumption increased from 15.56 ± 4.05 to 18.4 ± 5.2 mL/kg/min (p = 0.03) but did not change in the sham group (p = 0.53); p for intergroup comparison was 0.03. In contrast, there was no difference in the improvement of the CCS class or SAQ domains. To conclude, in patients with refractory angina and optimized medical therapy, CSR implantation may improve oxygen consumption beyond that of optimal medical therapy.

Coronary sinus Reducer device for the treatment of refractory angina: A multicenter initial experience

INTRODUCTION

The coronary sinus Reducer (CSR) device has emerged as a complementary therapy in patients with severe angina refractory to optimal medical therapy and not amenable to revascularization. Our aim was to assess the safety and efficacy of the CSR in a real-world setting.

METHODS

Twenty-six patients with refractory angina (RA) and evidence of myocardial ischemia attributable to the left coronary artery considered unsuitable for revascularization were treated with the CSR at two centers between May 2017 and July 2019. Safety endpoints were procedural success and complications. Efficacy endpoints, assessed at six-month follow-up, were reduction in CCS class, improvement in quality of life (QoL) assessed using the short version of the Seattle Angina Questionnaire (SAQ-7), and reduction in antianginal therapy.

RESULTS

Twenty-three patients had end-stage coronary artery disease without revascularization targets and three had microvascular disease without epicardial stenosis. Procedural success was achieved in 23 patients, with two device/procedure-related complications and one anatomically-related failure to deliver the device. A total of 25 patients had the device implanted and entered the efficacy analysis. Eighteen patients (75.0%) had a reduction of at least one CCS class, 41.7% had a reduction of at least two classes, and 16.7% became asymptomatic, with a mean reduction in CCS class of 1.3±0.2 (p=0.001) at six-month follow-up. All SAQ-7 domains improved, notably physical limitation (p=0.001), angina frequency (p=0.005) and QoL (p=0.006). There was a mean reduction in anti-ischemic drugs from 3.4±1.1 to 2.9±1.2 (p=0.010).

CONCLUSION

In this real-world, multicenter experience, implantation of the CSR was associated with improvement in angina and QoL in patients with RA.

Coronary sinus for cardiac resynchronization therapy: leave it alone and go for the branch! a case report

Background

Coronary sinus is the target of an increasing number of percutaneous interventional procedures. Thus, in some patients, conventional cardiac resynchronization therapy (CRT) may not be feasible or preferable, and 'alternative' CRT approaches should be applied.

Case summary

We present the case of a successful CRT via direct left bundle branch permanent pacing (LBBP) in a patient with relative contraindication to conventional CRT because of previous percutaneous indirect mitral annuloplasty.

Discussion

LBBP is emerging as a promising technique for physiological cardiac pacing and CRT. It may represent the technique of choice when coronary sinus is not viable for the implant of a conventional left ventricular catheter.

Transcatheter Coronary Sinus Interventions

The coronary sinus has become a popular route for an increasing number of innovative transcatheter interventions to treat coronary and structural heart diseases. However, interventional cardiologists have limited experience with the cardiac venous system and its highly variable anatomy. In this paper, we review the anatomy of the cardiac veins as it relates to transcatheter interventions. We also provide a contemporary overview of the emerging coronary sinus-based transcatheter therapies and their growing literature.

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.

Coronary sinus reducer for the treatment of chronic refractory angina pectoris

Refractory angina represents the final stage of chronic coronary artery disease, where anginal symptoms persist despite complete epicardial coronary artery revascularization and maximally tolerated pharmacological therapy. Percutaneous narrowing of the coronary sinus with the Coronary Sinus Reducer^® device was first attempted in humans in 2005 and has been shown to improve angina symptoms and the quality of life of patients suffering chronic refractory angina. It was recently included in the European guidelines for the management of chronic coronary syndrome and is progressively gaining popularity. The authors hereby provide a review of current literature on the topic, intending to facilitate insights and to promote further research on this device and its clinical applications.

The Effectiveness of CS Reducer for the treatment of Refractory Angina - a Meta-Analysis

BACKGROUND

Refractory angina is a debilitating condition that affects quality of life of patients worldwide, that after exhausting standard available therapies are regarded as "no option" patients. Recently, coronary sinus (CS) Reducer implantation became available and is gaining popularity in the treatment of refractory angina. The effectiveness of this therapy was demonstrated in one randomized sham-control trial and numerous uncontrolled prospective studies entailing altogether several hundred patients. We performed a meta-analysis to incorporate the data and elucidate its efficacy and safety.

METHODS

A meta-analysis of prospective studies assessing the effects of CS narrowing published in English until June 2021 was performed. The primary outcome was the proportion of patients improving ≥1 class in the Canadian Cardiovascular Society (CSS) angina score. Other endpoints included proportion of patients improving ≥2 CCS classes, procedural success, periprocedural complications, changes in Seattle Angina Questionnaire (SAQ) scores, and six-minute walk test (6MWT).

RESULTS

Data from 9 studies, including 846 patients was included. An improvement of ≥1 CSS class occurred in 76% [95% CI 73%- 80%] of patients. Improvement of ≥2 CSS classes was observed in 40% of patients (95% CI of 35-46%). Procedure success was 98%, with no major and 3% of non-major periprocedural complications. Post procedural SAQ scores and 6MWT distance were significantly improved.

CONCLUSIONS

In patients suffering from angina refractory to medical and interventional therapies, CS narrowing implantation improves symptoms and quality of life, with a low complication rate. These results are consistent in one randomized trial and in multiple prospective, uncontrolled studies.

Coronary Sinus Reducer: A Solution for patients with Refractory Angina

Refractory Angina (RA) places a great burden on patients and the healthcare system, with reduced quality of life (QOL), increased hospital admissions, polypharmacy, and psychological effects. Patients with RA are limited in options for management and with the introduction of the coronary sinus reducer (CSR), a safe and effective option may be available for this group of patients. This review article seeks to understand the efficacy of coronary sinus implantation in the current literature.

Management of ischaemia with non-obstructive coronary arteries (INOCA)

Up to half of patients undergoing elective coronary angiography for the investigation of chest pain do not present with evidence of obstructive coronary artery disease. These patients are often discharged with a diagnosis of non-cardiac chest pain, yet many could have an ischaemic basis for their symptoms. This type of ischaemic chest pain in the absence of obstructive coronary artery disease is referred to as INOCA (ischaemia with non-obstructive coronary arteries). This comprehensive review of INOCA management looks at why these patients require treatment, who requires treatment based on diagnostic evaluation, what clinical treatment targets should be considered, how to treat patients using a personalised medicine approach, when to initiate treatment, and where future research is progressing.

Son of a Lesser God: The Case of Cell Therapy for Refractory Angina

In the last decades, various non-pharmacological solutions have been tested on top of medical therapy for the treatment of patients affected by refractory angina (RA). Among these therapeutics, neuromodulation, external counter-pulsation and coronary sinus constriction have been recently introduced in the guidelines for the management of RA in United States and Europe. Notably and paradoxically, although a consistent body of evidence has proposed cell-based therapies (CT) as safe and salutary for RA outcome, CT has not been conversely incorporated into current international guidelines yet. As a matter of fact, published randomized controlled trials (RCT) and meta-analyses (MTA) cumulatively indicated that CT can effectively increase perfusion, physical function and well-being, thus reducing angina symptoms and drug assumption in RA patients. In this review, we (i) provide an updated overview of novel non-pharmacological therapeutics included in current guidelines for the management of patients with RA, (ii) discuss the Level of Evidence stemmed from available clinical trials for each recommended treatment, and (iii) focus on evidence-based CT application for the management of RA.

Coronary sinus narrowing for the treatment of refractory angina: a multicentre prospective open-label clinical study (the REDUCER-I study)

BACKGROUND

The REDUCER-I study is a prospective (with a retrospective component), open-label, multi-centre, international, post-market study, which collects long-term data of patients with refractory angina treated with the Reducer. Here we present the overall clinical outcomes of the first 228 patients enrolled.

AIMS

The aim of this study is to examine the safety and efficacy of the coronary sinus (CS) Reducer in improving angina severity and quality of life in patients suffering from angina pectoris, refractory to medical and interventional therapies.

METHODS

REDUCER-I is a multicentre, non-randomised observational study. Enrolled patients had refractory angina pectoris Canadian Cardiovascular Society (CCS) class II-IV and were treated with Reducer implantation.

RESULTS

In the first 228 patients (81% male, 68.3±9.6 years), the procedural success rate was 99%, with only one adjudicated possible procedural or device-related MACE. Mean CCS class decreased from 2.8±0.6 at baseline, to 1.8±0.7 at two years. Improvement in ≥1 CCS class was observed in 82%, and in ≥2 CCS classes in 31% of patients at two years. At baseline, 70% of the cohort were reported to be in CCS class III-IV; this portion was reduced to 15% at follow-up. Additional measured parameters of functional class and quality of life were also improved.

CONCLUSIONS

Interim results from the ongoing REDUCER-I study confirm the high safety profile of this therapy in patients suffering from refractory angina. The results also demonstrate sustained improvement in angina severity and in quality of life up to two years.

Coronary sinus anatomical features: Description and procedural implications during coronary sinus Reducer implantation

OBJECTIVES

We hypothesized that some coronary sinus (CS) anatomies allow a more straightforward CS Reducer (CSR) implantation.

BACKGROUND

Recent decades have seen a rise in patients with chronic angina. When complete revascularization and maximal medical therapy fail to reduce symptoms, CSR has become a new therapeutic option.

METHODS

We identified a classical C-shape-a near horizontal course of the proximal portion of a circular CS-in a retrospective analysis of 47 CSR implantations and compared the procedural time, fluoroscopic time, contrast use, presence of valves or bifurcations and procedural complications with the non-C-shape CS anatomy.

RESULTS

We found a significant difference in procedural (20.0 [19.0-24.7] min vs. 24.5 [20.7-51.0] min; p = .028 and fluoroscopic time (9.5 [7.5-14.5] min vs. 11.0 [7.9-30.0] min; p = .016). There was no significant difference in contrast use. The presence of bifurcations or valves along the CS course did not influence the procedural timings.

CONCLUSION

This study is the first systematic evaluation of CS anatomy and its procedural implications. We identified a favorable C-shape anatomy which allows for a more straightforward implantation. Operators should be aware of the different implications of CS anatomy, their influence on guiding catheter stability and overall procedure complexity.

Safety and efficacy of coronary sinus narrowing in chronic refractory angina: Insights from the RESOURCE study

INTRODUCTION

Refractory angina (RA) is considered the end-stage of coronary artery disease, and often has no interventional treatment options. Coronary sinus Reducer (CSR) is a recent addition to the therapeutic arsenal, but its efficacy has only been evaluated on small populations. The RESOURCE registry provides further insights into this therapy.

METHODS

The RESOURCE is an observational, retrospective registry that includes 658 patients with RA from 20 centers in Europe, United Kingdom and Israel. Prespecified endpoints were the amelioration of anginal symptoms evaluated with the Canadian Cardiovascular Society (CCS) score, the rates of procedural success and complications, and MACEs as composite of all-cause mortality, acute coronary syndromes, and stroke.

RESULTS

At a median follow-up of 502 days (IQR 225-1091) after CSR implantation, 39.7% of patients improved by ≥2 CCS classes (primary endpoint), and 76% by ≥1 class. Procedural success was achieved in 96.7% of attempts, with 3% of procedures aborted mostly for unsuitable coronary sinus anatomy. Any complication occurred in 5.7% of procedures, but never required bailout surgery nor resulted in intra- or periprocedural death or myocardial infarction. One patient developed periprocedural stroke after inadvertent carotid artery puncture. At the last available follow-up, overall mortality and MACE were 10.4% and 14.6% respectively. At one, three and five years, mortality rate at Kaplan-Meier analysis was 4%, 13.7%, and 23.4% respectively.

CONCLUSIONS

CSR implantation is safe and reduces angina in patients with refractory angina.

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.

Non-pharmacological treatment of refractory angina: The coronary sinus reducer, the new kid on the block

Refractory angina is defined as persistent angina (≥3 months) despite optimal medical and interventional therapies. It is increasing in frequency, due to the success of current medical and interventional therapies in improving the prognosis of coronary artery disease. Long-term mortality is similar to that of patients with asymptomatic stable disease, but it affects patients' quality of life, and has a significant impact on health care resources. Several therapeutic targets have been investigated, most with disappointing results. Many of the techniques have been abandoned because of lack of efficacy, safety issues, or economic and logistic limitations to wider applicability. The primary focus of this review is the coronary sinus Reducer, supporting evidence for which, although scarce, is promising regarding safety and efficacy in improving anginal symptoms and quality of life. It is also accessible to virtually all interventional cardiology departments.

Non-pharmacological treatment of refractory angina: The coronary sinus reducer, the new kid on the block

Refractory angina is defined as persistent angina (≥3 months) despite optimal medical and interventional therapies. It is increasing in frequency, due to the success of current medical and interventional therapies in improving the prognosis of coronary artery disease. Long-term mortality is similar to that of patients with asymptomatic stable disease, but it affects patients' quality of life, and has a significant impact on health care resources. Several therapeutic targets have been investigated, most with disappointing results. Many of the techniques have been abandoned because of lack of efficacy, safety issues, or economic and logistic limitations to wider applicability. The primary focus of this review is the coronary sinus Reducer, supporting evidence for which, although scarce, is promising regarding safety and efficacy in improving anginal symptoms and quality of life. It is also accessible to virtually all interventional cardiology departments.

Coronary Sinus Reducer for the Treatment of Chronic Refractory Angina: Will This Challenge the Treatment of Coronary Chronic Total Occlusions?

PURPOSE OF REVIEW

The prevalence of angina despite optimal medical therapy is high among patients with coronary chronic total occlusions. Despite advancements in techniques and operator's experience, percutaneous revascularization of coronary chronic total occlusions is still associated with a not negligible risk of failures and complications. The Coronary Sinus Reducer, a new device developed to improve angina, has shown promising results in terms of efficacy and safety in patients with refractory symptoms. The aim of this review is to summarize the evidence so far available and to guide clinicians in the selection of patients with chronic total occlusions that could benefit more from Coronary Sinus Reducer implantation.

RECENT FINDINGS

A recently published study suggests a clear value of this device in patients with chronic total occlusions. This is likely to be related to the presence of a well-developed collateral circulation. A careful evaluation of risks and benefits of both myocardial revascularization and Coronary Sinus Reducer implantation should be done in all the cases in order to better define the optimal strategy for the patient. The Coronary Sinus Reducer implantation has a rationale in patients with chronic total occlusion as an alternative or additional therapy to myocardial revascularization.

Long-term outcomes of patients undergoing coronary sinus reducer implantation - A multicenter study

BACKGROUND

Coronary sinus (CS) narrowing by reducer implantation has emerged as a safe and effective therapy for patients suffering from refractory angina. However, data regarding the clinical benefit of this treatment over time is lacking.

METHODS

Patients undergoing successful reducer implantation were enrolled prospectively to clinical registries at three medical centers. Those with more than 2-years of follow-up were included in the present analysis. Peri-procedural data, data regarding adverse events, and current evaluation of angina severity (Canadian Cardiovascular Society [CCS] class) were collected.

RESULTS

Overall, 99 consecutive patients (77% males, mean age 69.8 ± 9.4) with severe angina were enrolled between September 2010 and October 2017 and included in the present analysis. No procedure-related complications were recorded. During a median follow up time of 3.38 years (IQR 2.95-4.40), 15.1% of the patients died, 9% experienced myocardial infarction (MI) and 21% underwent percutaneous coronary intervention (PCI). Mean CCS class was 3.1 ± 0.5 at baseline, improved to 1.66 ± 0.8 at 1 year (p < .001), and remained low through 2-years and at last follow up (1.72 ± 0.8 and 1.71 ± 0.8, p > 0.5 for both, in comparison to 1 year). At baseline 91% of patients reported severe disabling angina (CCS class 3-4), at 1 year only 17.9% suffered from disabling angina, p < .001, and this portion remained low overtime (19% at last follow up).

CONCLUSION

Long-term mortality of patients undergoing reducer implantation is similar to that reported for patients with stable coronary artery disease. The previously reported short-term efficacy of the reducer, reflected by significant improvement of angina symptoms, is maintained over time.

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.

Usefulness of Coronary Sinus Reducer Implantation for the Treatment of Chronic Refractory Angina Pectoris

The coronary sinus (CS) Reducer is a novel device designed for the management of patients with severe angina symptoms refractory to optimal medical therapy and not amenable to further revascularization. Aim of this study was to investigate the efficacy and the safety of the CS Reducer device in a real-world, multicenter, and country-level cohort of patients presenting with refractory angina pectoris. The study included patients affected by refractory angina pectoris who underwent CS Reducer implantation in 16 centers. Clinical follow-up was carried as per each center's protocol. One hundred eighty-seven patients were included. Technical and procedural success were achieved in 98% and 95%, respectively. Minor peri-procedural complications were recorded in 8 patients. During a median follow-up of 18.4 months, 135 (82.8%) patients demonstrated at least 1 CCS class reduction after Reducer implantation, and 80 (49%) patients at least 2 CCS class reduction. Mean CCS class improved from 3.05 ± 0.53 at baseline to 1.63 ± 0.98 at follow-up (p < 0.001). Treatment benefit was also reflected in a significant improvement in quality of life scores and in a reduction of the mean number of anti-ischemic drugs prescribed for patient. In conclusion, in this multicenter, country-level study, the implantation of CS Reducer in patients with refractory angina pectoris resulted to be safe and effective in reducing of angina pectoris and improving quality of life.

Coronary Sinus Reducing Stent for the Treatment of Refractory Angina Pectoris: A Health Technology Assessment

Aim

To summarize the evidence on the clinical effectiveness and safety of coronary sinus reducing stent (CSRS) therapy in refractory angina pectoris (AP) patients.

Methods

We performed a systematic literature search in common databases (n=4). The evidence obtained was summarized according to GRADE methodology. A health technology assessment (HTA) was conducted using the HTA Core Model^® for Rapid Relative Effectiveness Assessment. Primary outcomes for the clinical effectiveness domain were the proportion of patients with improvement in two or more Canadian Cardiovascular Society (CCS) angina score classes, overall mean reduction of CCS class, and Seattle Angina Questionnaire (SAQ) quality of life (QoL) score improvement. Outcomes for the safety domain were adverse device effects (ADEs) and serious adverse device effects (SADEs).

Results

One randomized controlled trial (RCT) was identified. Outcomes that showed statistically significant differences between CSRS and sham treatment (in favor of CSRS) were CCS angina score improvement of one or two classes, overall mean reduction of CCS class, and SAQ QoL score improvement. Concerning safety, the sham-controlled trial data indicate that there were fewer SADEs in the intervention group (19%) than in the control group (46%). SADEs reported in observation studies ranged from none to 30%. The most frequently reported SADEs were death and stable angina. In the RCT, the only case of death occurred in the control group. Concerning clinical effectiveness, the risk of bias (RoB) was rated to be low, and concerning safety, the RoB was rated to range from low to moderate. As assessed by GRADE, the overall strength of evidence for effectiveness and safety was moderate. Internal and external validity of the evidence base were low.

Conclusion

Even though the current evidence indicates that the assessed technology, CSRS, is potentially more effective than sham intervention for refractory AP patients, the lack of internal validity of the studies undermines the partially positive results.

Non-pharmacological Treatment of Refractory Angina and Microvascular Angina

Refractory angina (RA) is defined as debilitating anginal symptoms despite the optimal guideline-directed combination of medical, percutaneous, and surgical therapies. Often referred to as “no option”, these patients represent a significant unmet clinical need for healthcare institutions. Due to the ageing of the population, and increased survival from coronary artery disease, the number of patients with RA is expected to rise exponentially. Despite the developments of novel technologies for the treatment of RA, none of them found wide clinical application (to date). Microvascular dysfunction, alone or in combination with epicardial coronary disease, is thought to contribute significantly to refractory angina. However, most of the techniques developed to improve RA symptoms have not been tested specifically on patients with microvascular dysfunction. This review discusses the recent developments in the treatment of RA, and gives some perspectives on the future of these techniques.

Technical aspects in coronary sinus Reducer implantation

Refractory angina is a growing problem, predominantly due to advanced coronary artery disease, associated with a reduced quality of life and an increased hospitalisation rate with a corresponding impact on healthcare resources. There is an unmet clinical need to be addressed by novel therapeutic approaches. Over the last few years, a treatment approach causing a controlled coronary sinus narrowing by implantation of a balloon-expandable, hourglass-shaped, stainless steel mesh (i.e., the coronary sinus Reducer) has arisen with promising initial short-term and midterm results, in terms of reducing angina and ischaemia burden and improving quality of life. Guidance with proper implantation algorithms and knowledge on how to address potential complications will improve interventional outcomes and foster a wider application of this novel therapeutic approach. In this review, we summarise the implantation technique, the causes of potential complications, and algorithms focusing upon their practical management, based on the experience of the authors.

The Coronary Sinus Reducer – Clinical Evidence and New Perspectives On An Emerging Tool in the Treatment of Refractory Angina

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Percutaneous management of periprocedural coronary sinus Reducer migration

Coronary sinus Reducer represents a novel therapeutic option for refractory angina. As emerging evidence of both reduction in angina symptoms and reduction of myocardial ischemia burden might lead to increased Reducer implantations, knowledge on how to manage potential complications is of clinical importance. We report a successful management of scaffold migration in right atrium.

The efficacy of coronary sinus reducer in patients with refractory angina-A systematic review of the literature

OBJECTIVES

The aim of our systematic review was to investigate the efficacy of coronary sinus (CS) reducer device in patients with refractory angina.

BACKGROUND

The CS reducer device provides a therapeutic option for patients with coronary artery disease who are not suitable for revascularization.

METHODS

Two independent investigators (GB and GT) systematically searched the Medline and Cochrane library databases for studies describing the efficacy and safety of the CS reducer in patients with refractory angina from January 1, 2000 until May 12, 2018 using the following terms: "coronary sinus (reducer OR reducing) device." Efficacy was defined as ≥1 unit improvement in the Canadian cardiovascular society (CCS) score.

RESULTS

Our search strategy provided six studies (five observational studies and one randomized clinical trial) with 196 patients. The CS reducer device was effective in 146/186 (78.5%) patients. CCS score improved from 3.2 at baseline to 1.9 after 8.6 months of follow-up. The efficacy of CS reducer device was also demonstrated as an improvement in Seattle Angina Questionnaire score, dobutamine echocardiography, thalium single-photon emission computed tomography perfusion studies, 6-min-walk test and myocardial perfusion reserve index. Implantation failed in 4 of 196 (2%) patients and 5 patients (2.5%) had a complication during 30-day follow-up.

CONCLUSIONS

The CS reducer is a promising treatment option for patients with refractory angina who are not candidates for revascularization. However, larger randomized control trials with long-term follow-up are needed to elucidate its role.