Safety and efficacy of a device to narrow the coronary sinus for the treatment of refractory angina: A single-centre real-world experience

Coronary Sinus Narrowing Improves Coronary Microcirculation Function in Patients With Refractory Angina: A Multicenter Prospective INROAD Study

BACKGROUND

The underlying mechanisms responsible for the clinical benefits following coronary sinus narrowing and pressure elevation remain unclear. The present study aims to investigate whether coronary sinus narrowing improves the indexes of coronary microcirculatory function.

METHODS

Patients with refractory angina who had a clinical indication for reducer implantation underwent invasive physiological assessments before and 4 months after the procedure. The primary outcome was the change in the values of the index of microcirculatory resistance. Secondary end points included changes in coronary flow reserve and the resistive resistance ratio values. Angina status was assessed with the Canadian Cardiology Society class and the Seattle Angina Questionnaire.

RESULTS

Twenty-four patients with a history of obstructive coronary artery disease and prior coronary revascularization (surgical and percutaneous) treated with reducer implantation were enrolled, and 21 of them (87%) underwent repeated invasive coronary physiological assessment after 4 months. The index of microcirculatory resistance values decreased from 33.35±19.88 at baseline to 15.42±11.36 at 4-month follow-up (P<0.001; mean difference, -17.90 [95% CI, -26.16 to -9.64]). A significant (≥20% from baseline) reduction of the index of microcirculatory resistance was observed in 15 (71.4% [95% CI, 47.8%-88.7%]) patients. The number of patients with abnormal index of microcirculatory resistance (≥25) decreased from 12 (57%) to 4 (19%; P=0.016). Coronary flow reserve increased from 2.46±1.52 to 4.20±2.52 (mean difference, 1.73 [95% CI, 0.51-2.96]). Similar findings were observed for resistive resistance ratio values. Overall, 16 patients (76.1%) had an improvement of 1 Canadian Cardiology Society class. Seattle Angina Questionnaire summary score increase of around 3 points (3.01 [95% CI, 1.39-4.61]).

CONCLUSIONS

Coronary sinus reduction implantation is associated with a significant improvement in the parameters of coronary microcirculatory function. These findings provide insights into the improvement of angina symptoms and may have implications for the treatment of coronary microvascular dysfunction.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT05174572.

[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.

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.

Pressure-Controlled Intermittent Coronary Sinus Occlusion: A Novel Approach to Improve Microvascular Flow and Reduce Infarct Size in STEMI

Despite successful primary percutaneous coronary intervention (PCI) for treatment of ST-segment elevation myocardial infarction (STEMI), myocardial salvage is frequently suboptimal resulting in large infarctions with increased rates of heart failure and death. Microvascular dysfunction after the procedure is frequently present and contributes directly to poor outcomes in STEMI. Pressure-controlled intermittent Coronary Sinus Occlusion (PiCSO) is a novel technology designed to mitigate microvascular dysfunction in STEMI. Non-randomized studies have suggested that PiCSO use during primary PCI in STEMI is safe, improves microvascular perfusion and reduces infarct size. Randomized trials are ongoing to investigate the safety and effectiveness of PiCSO in high-risk patients with anterior STEMI undergoing primary PCI.

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.

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 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.

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.

The Coronary Sinus Reducer; 5-year Dutch experience

Background

Refractory angina is a growing and major health-care problem affecting millions of patients with coronary artery disease worldwide. The Coronary Sinus Reducer (CSR) is a device that may be considered for the relief of symptoms of refractory angina. It causes increased venous pressure leading to a dilatation of arterioles and reduced arterial vascular resistance in the sub-endocardium. This study describes the 5‑year Dutch experience regarding safety and efficacy of the CSR.

Methods

One hundred and thirty-two patients with refractory angina were treated with the CSR. The primary efficacy endpoint of the study was Canadian Cardiovascular Society (CCS) class improvement between baseline and 6‑month follow-up. The primary safety endpoint was successful CSR implantation in the absence of any device-related events.

Results

Eighty-five patients (67%) showed improvement of at least 1 CCS class and 43 patients (34%) of at least 2 classes. Mean CCS class improved from 3.17 ± 0.61 to 2.12 ± 1.07 after implantation (P < 0.001). The CSR was successfully implanted in 99% of the patients and only minor complications during implantation were reported.

Conclusion

The CSR is a simple, safe, and effective option for most patients with refractory angina. However, approximately thirty percent of the patients showed no benefit after implantation. Future studies should focus on the exact underlying mechanisms of action and reasons for non-response to better identify patients that could benefit most from this therapy.

Electronic supplementary material

The online version of this article (10.1007/s12471-020-01525-8) contains supplementary material, which is available to authorized users.

Refractory Angina: From Pathophysiology to New Therapeutic Nonpharmacological Technologies

Despite optimal combination of guideline-directed anti-ischemic therapies and myocardial revascularization, a substantial proportion of patients with stable coronary artery disease continues to experience disabling symptoms and is often referred as "no-option." The appraisal of the pathways linking ischemia to symptom perception indicates a complex model of heart-brain interactions in the generation of the subjective anginal experience and inspired novel approaches that may be clinically effective in alleviating the angina burden of this population. Conversely, the prevailing ischemia-centered view of angina, with the focus on traditional myocardial revascularization as the sole option to address ischemia on top of medical therapy, hinders the experimental characterization and broad-scale clinical implementation of strongly needed therapeutic options. The interventionist, often the first physician to establish the diagnosis of refractory angina pectoris (RAP) following coronary angiography, should be aware of the numerous emerging technologies with the potential to improve quality of life in the growing population of RAP patients. This review describes the current landscape and the future perspectives on nonpharmacological treatment technologies for patients with RAP, with a view on the underlying physiopathological rationale and current clinical evidence.

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.

Efficacy of Coronary Sinus Reducer in Patients With Non-revascularized Chronic Total Occlusions

The coronary sinus reducer (CSR) has been introduced as therapy for patients with refractory angina with no other treatment options. Aim of this study is to investigate the efficacy of the CSR in patients with refractory angina and presence of coronary chronic total occlusions (CTO). In this multicentre, international retrospective study, patients undergoing CSR implantation were screened and divided in 2 groups according to the presence/absence of CTO lesions. Baseline and clinical characteristics were analyzed in the 2 groups. Primary-outcome consisted of the variation in Canadian Cardiovascular Society (CCS) class at 6-month follow-up. Between January 2014 and December 2018, 205 patients with refractory angina were consecutively treated with the study device in the participating centers, 103 (50.2%) of which had a CTO lesion at coronary angiogram and formed the CTO-group. Baseline characteristics of the study population were well balanced between the 2 groups. CSR was successfully implanted in all cases. Baseline CCS class was 3  ±  0.5 in the CTO-group versus 3.1  ±  0.6 in the non-CTO group (p = 0.45), and improved at follow-up to 1.6  ±  0.9 versus 2  ±  1.1 respectively (p <0.01), with a significantly higher improvement in CCS class in the CTO-group (1.4  ±  0.9 vs 1.1  ±  1 respectively, p = 0.01). Any improvement in CCS class was registered in 79 (80.6%) CTO-patients, while a significantly lower percentage (65 patients, 66.3%) of the non-CTO patients reported benefits in CCS class (p = 0.03). In conclusions, patients suffering from refractory angina with non-revascularized CTO lesions have a better response to CSR implantation than patients without CTOs. CSR implantation should be considered a valid complementary therapy to CTO-PCI in these patients.

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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The Reducer device in patients with angina pectoris: mechanisms, indications, and perspectives

Despite available pharmacological and interventional therapies, refractory angina is a common and disabling clinical condition, and a major public health problem, which affects patients' quality-of-life, and has a significant impact upon health care resources. Persistent angina is common not only in patients who are not good candidates for revascularization, but also in patients following successful revascularization. Clearly, there is a need for additional treatment options for refractory angina beyond currently available pharmacological and interventional therapies. It is of pivotal importance, in this condition, to practice a patient-centred health assessment approach, measuring success of a new therapy by its effects on patients' symptoms, functional status, and quality-of-life, rather than hard clinical endpoints as used in clinical studies. The coronary sinus Reducer is a novel technology designed to reduce disabling symptoms and improve quality-of-life of patients suffering from refractory angina. This review serves to update the clinician as to current evidence and future perspectives of the optimal utilization of this innovative technology.

Incomplete coronary sinus reducer endothelialization as potential mechanism of clinical failure

The number of patients suffering from refractory angina is constantly increasing. Moreover, these patients are considered at higher risk for new hospitalizations and increased incidence of adverse cardiac events. The coronary sinus reducer was recently introduced as a new therapeutic option in patients with refractory angina and no possibilities for coronary revascularization. However, a consistent percentage of patients, ranging from 15 to 30%, reports no clinical benefits after coronary sinus reducer implantation. The reasons for this lack of effectiveness are at present unknown. We suggest here a possible explanation to this phenomenon.

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.

Linking cell function with perfusion: insights from the transcatheter delivery of bone marrow-derived CD133+ cells in ischemic refractory cardiomyopathy trial (RECARDIO)

Background

Cell therapy with bone marrow (BM)-derived progenitors has emerged as a promising therapeutic for refractory angina (RA) patients. In the present study, we evaluated the safety and preliminary efficacy of transcatheter delivery of autologous BM-derived advanced therapy medicinal product CD133⁺ cells (ATMP-CD133) in RA patients, correlating perfusion outcome with cell function.

Methods

In the phase I “Endocavitary Injection of Bone Marrow Derived CD133⁺ Cells in Ischemic Refractory Cardiomyopathy” (RECARDIO) trial, a total of 10 patients with left ventricular (LV) dysfunction (ejection fraction ≤ 45%) and evidence of reversible ischemia, as assessed by single-photon emission computed tomography (SPECT), underwent BM aspiration and fluoroscopy-based percutaneous endomyocardial delivery of ATMP-CD133. Patients were evaluated at 6 and 12 months for safety and preliminary efficacy endpoints. ATMP-CD133 samples were used for in vitro correlations.

Results

Patients were treated safely with a mean number of 6.57 ± 3.45 ×  10⁶ ATMP-CD133. At 6-month follow-up, myocardial perfusion at SPECT was significantly ameliorated in terms of changes in summed stress (from 18.2 ± 8.6 to 13.8 ± 7.8, p = 0.05) and difference scores (from 12.0 ± 5.3 to 6.1 ± 4.0, p = 0.02) and number of segments with inducible ischemia (from 7.3 ± 2.2 to 4.0 ± 2.7, p = 0.003). Similarly, Canadian Cardiovascular Society and New York Heart Association classes significantly improved at follow-up vs baseline (p ≤ 0.001 and p = 0.007, respectively). Changes in summed stress score changes positively correlated with ATMP-CD133 release of proangiogenic cytokines HGF and PDGF-bb (r = 0.80, p = 0.009 and r = 0.77, p = 0.01, respectively) and negatively with the proinflammatory cytokines RANTES (r = − 0.79, p = 0.01) and IL-6 (r = − 0.76, p = 0.02).

Conclusion

Results of the RECARDIO trial suggested safety and efficacy in terms of clinical and perfusion outcomes in patients with RA and LV dysfunction. The observed link between myocardial perfusion improvements and ATMP-CD133 secretome may represent a proof of concept for further mechanistic investigations.

Trial registration

ClinicalTrials.gov, NCT02059681. Registered 11 February 2014.

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.

New Advances in the Management of Refractory Angina Pectoris

Refractory angina is a significant clinical problem and its successful management is often extremely challenging. Defined as chronic angina-type chest pain in the presence of myocardial ischaemia that persists despite optimal medical, interventional and surgical treatment, current therapies are limited and new approaches to treatment are needed. With an ageing population and increased survival from coronary artery disease, clinicians will increasingly encounter this complex condition in routine clinical practice. Novel therapies to target myocardial ischaemia in patients with refractory angina are at the forefront of research and in this review we discuss those in clinical translation and assess the evidence behind their efficacy.

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.

Management of Refractory Angina Pectoris

With improvements in survival from coronary artery disease (CAD) and an ageing population, refractory angina (RA) is becoming an increasingly common clinical problem facing clinicians in routine clinical practice. These patients experience chronic symptoms in the context of CAD, characterised by angina-type pain, which is uncontrolled despite optimal pharmacological, interventional and surgical therapy. Although mortality rates are no worse in this cohort, patients experience a significantly impaired quality of life with disproportionately high utilisation of healthcare services. It has been increasingly recognised that the needs of RA patients are multifactorial and best provided by specialist multi-disciplinary units. In this review, we consider the variety of therapies available to clinicians in the management of RA and discuss the promise of novel treatments.