Patterns of Regional Myocardial Perfusion Following Coronary Sinus Reducer Implantation: Insights by Stress Cardiac Magnetic Resonance

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.

Coronary sinus reducer for the treatment of refractory angina (ORBITA-COSMIC): a randomised, placebo-controlled trial

BACKGROUND

The coronary sinus reducer (CSR) is proposed to reduce angina in patients with stable coronary artery disease by improving myocardial perfusion. We aimed to measure its efficacy, compared with placebo, on myocardial ischaemia reduction and symptom improvement.

METHODS

ORBITA-COSMIC was a double-blind, randomised, placebo-controlled trial conducted at six UK hospitals. Patients aged 18 years or older with angina, stable coronary artery disease, ischaemia, and no further options for treatment were eligible. All patients completed a quantitative adenosine-stress perfusion cardiac magnetic resonance scan, symptom and quality-of-life questionnaires, and a treadmill exercise test before entering a 2-week symptom assessment phase, in which patients reported their angina symptoms using a smartphone application (ORBITA-app). Patients were randomly assigned (1:1) to receive either CSR or placebo. Both participants and investigators were masked to study assignment. After the CSR implantation or placebo procedure, patients entered a 6-month blinded follow-up phase in which they reported their daily symptoms in the ORBITA-app. At 6 months, all assessments were repeated. The primary outcome was myocardial blood flow in segments designated ischaemic at enrolment during the adenosine-stress perfusion cardiac magnetic resonance scan. The primary symptom outcome was the number of daily angina episodes. Analysis was done by intention-to-treat and followed Bayesian methodology. The study is registered with ClinicalTrials.gov, NCT04892537, and completed.

FINDINGS

Between May 26, 2021, and June 28, 2023, 61 patients were enrolled, of whom 51 (44 [86%] male; seven [14%] female) were randomly assigned to either the CSR group (n=25) or the placebo group (n=26). Of these, 50 patients were included in the intention-to-treat analysis (24 in the CSR group and 26 in the placebo group). 454 (57%) of 800 imaged cardiac segments were ischaemic at enrolment, with a median stress myocardial blood flow of 1·08 mL/min per g (IQR 0·77-1·41). Myocardial blood flow in ischaemic segments did not improve with CSR compared with placebo (difference 0·06 mL/min per g [95% CrI -0·09 to 0·20]; Pr(Benefit)=78·8%). The number of daily angina episodes was reduced with CSR compared with placebo (OR 1·40 [95% CrI 1·08 to 1·83]; Pr(Benefit)=99·4%). There were two CSR embolisation events in the CSR group, and no acute coronary syndrome events or deaths in either group.

INTERPRETATION

ORBITA-COSMIC found no evidence that the CSR improved transmural myocardial perfusion, but the CSR did improve angina compared with placebo. These findings provide evidence for the use of CSR as a further antianginal option for patients with stable coronary artery disease.

FUNDING

Medical Research Council, Imperial College Healthcare Charity, National Institute for Health and Care Research Imperial Biomedical Research Centre, St Mary's Coronary Flow Trust, British Heart Foundation.

A budget impact model and a cost-utility analysis of reducer device (Neovasc) in patients with refractory angina

Background

Refractory angina (RA) is a chronic condition characterized by the presence of debilitating angina symptoms due to established reversible ischemia in the presence of obstructive coronary artery disease (CAD). Treatments for this condition have undergone major developments in recent decades; however, the treatment for RA remains a challenge for medicine. In this sense, the Coronary Sinus Reducer System (CSRS) stands as the last line of therapy for ineligible patients for revascularization with reversible ischemia. The purpose of this report is to evaluate the potential burden on the National Health Service (NHS) and measure the health effects in terms of both quantity (life years) and quality-of-life aspects related to the reducer.

Methods

Two different economic evaluation models were developed as part of the analysis. The budget impact was developed to estimate the potential burden on the NHS from incremental uptake of the use of the reducer in the target population. The utility cost analysis compares and evaluates the quality of life and health resource use and costs between the two alternatives, based on the research of Gallone et al. A deterministic and probabilistic sensitivity analysis was carried out to characterize the uncertainty around the parameters of the model.

Results

In the budget impact analysis (BIA), the reducer is shown to be more expensive in the first 2 years of the model, due to the gradual uptake in the market and the cost of the device. Starting from the third year, assuming maintenance of effectiveness, there are savings in terms of resource absorption in direct healthcare costs arising from hospitalizations, emergency department accesses, coronarography, and visits avoided.

Conclusion

The BIA and cost-effectiveness model show that the reducer device, despite an increase in resources absorbed in the first years of implementation and use, has the potential to result in increased quality of life in patients with RA. These costs are largely offset in the short term by the improved clinical outcomes achievable leading to savings from the third year onward in the BIA and a dominance ratio in the cost-utility analysis.

A double-blind, randomised, placebo-controlled trial of the coronary sinus Reducer in refractory angina: design and rationale of the ORBITA-COSMIC trial

The coronary sinus Reducer (CSR) is an hourglass-shaped device which creates an artificial stenosis in the coronary sinus. Whilst placebo-controlled data show an improvement in angina, these results are unreplicated and are the subject of further confirmatory research. The mechanism of action of this unintuitive therapy is unknown. The Coronary Sinus Reducer Objective Impact on Symptoms, MRI Ischaemia, and Microvascular Resistance (ORBITA-COSMIC) trial is a randomised, placebo-controlled, double-blind trial investigating the efficacy of the CSR. Patients with (i) established epicardial coronary artery disease, (ii) angina on maximally tolerated antianginal medication, (iii) evidence of myocardial ischaemia and (iv) no further options for percutaneous coronary intervention or coronary artery bypass grafting will be enrolled. Upon enrolment, angina and quality-of-life questionnaires, treadmill exercise testing and quantitative stress perfusion cardiac magnetic resonance (CMR) imaging will be performed. Participants will record their symptoms daily on a smartphone application throughout the trial. After a 2-week symptom assessment phase, participants will be randomised in the cardiac catheterisation laboratory to CSR or a placebo procedure. After 6 months of blinded follow-up, all prerandomisation tests will be repeated. A prespecified subgroup will undergo invasive coronary physiology assessment at prerandomisation and follow-up. The primary outcome is stress myocardial blood flow on CMR. Secondary outcomes include angina frequency, quality of life and treadmill exercise time. (ClinicalTrials.gov: NCT04892537).

The Impact of Coronary Sinus Reducer on Arrhythmic Properties in Patients with Refractory Angina

Background

Treatment with a coronary sinus reducer (CSR) is a new therapeutic option for refractory angina patients. Preclinical studies have shown antiarrhythmic properties of coronary sinus narrowing. The possible antiarrhythmic effect of CSR implantation is unknown. This study aimed to determine the possible antiarrhythmic effects of CSR implantation as assessed by high-resolution electrocardiogram (hrECG) parameters.

Methods

24 patients from the Crossroad study randomized to either CSR treatment (n = 12) or a sham procedure (n = 12) had hrECG recorded at baseline and after 6 months. T-peak and T-end interval (TpTe) defined as the time difference between the peak amplitude of the T wave and the global end of the T wave, spatial angle between QRS complex and T axis defined as the angle between the ventricular depolarization and repolarization vectors using maximal (QRSTP) and mean (QRSTM) vector amplitudes and spatial ventricular gradient (SVG) calculated as integral of ECG voltages over the entire QRST complex were analyzed. Additionally, we analyzed parameters of QT and heart rate variability using time and frequency domain.

Results

At baseline, all analyzed parameters were comparable between both groups and heart rate remained constant. The intragroup analysis did not show any significant change in TpTe, QRSTP, QRSTM, SVG, QT, and heart rate variability at follow-up. Furthermore, intergroup comparison between CSR implantation and sham procedure also did not show any significant difference in the change of analyzed parameters.

Conclusions

Compared to the sham procedure, CSR implantation did not demonstrate a significant impact on the arrhythmogenic substrate assessed with hrECG.

Clinical Trial Registration

Unique Identifier: NCT04121845, https://classic.clinicaltrials.gov/ct2/show/NCT04121845.

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.

Implantation of the coronary sinus reducer for refractory angina due to coronary microvascular dysfunction in the context of apical hypertrophic cardiomyopathy-a case report

Background

Refractory angina leads to a poor quality of life and increased healthcare resource utilization. In this growing population of patients, multiple mechanism(s) of ischaemia may co-exist, including functional disorders of the coronary microcirculation. There are few evidence-based effective therapies resulting in a large unmet clinical need.

Case summary

A 38-year-old woman with refractory angina was referred with daily chest pain despite multiple anti-anginal medications and previous percutaneous coronary intervention. Cardiac magnetic resonance imaging demonstrated apical hypertrophic cardiomyopathy (HCM). Rubidium-82 positron emission tomography (PET) with regadenoson stress confirmed significant myocardial ischaemia in the apex and apical regions (16% of total myocardium) with a global myocardial perfusion reserve (MPR) of 1.23. Coronary angiography confirmed patent stents and no epicardial coronary artery disease. Therefore, the mechanism of ischaemia was thought attributable to coronary microvascular dysfunction (CMD) in the context of HCM. In view of her significant symptoms and large burden of left-sided myocardial ischaemia, a Coronary Sinus Reducer (CSR) was implanted. Repeat PET imaging at 6 months showed a marked reduction in ischaemia (<5% burden), improvement in global MPR (1.58), symptoms, and quality of life.

Conclusion

In refractory angina, ischaemia may be due to disorders of both the epicardial and coronary microcirculations. The CSR is a potential therapy for these patients, but its mechanism of action has not been confirmed. This report suggests that CSR implantation may reduce myocardial ischaemia and improve symptoms by acting on the coronary microcirculation. The efficacy of CSR in patients with CMD and its mechanism of action on the coronary microcirculation warrant further investigation.

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.

Double Reducer implantation in the coronary venous system for treatment of refractory angina: a case report

Background

The coronary sinus (CS) Reducer can be considered for the treatment of refractory angina in patients unsuitable for coronary revascularization, but its effect can be influenced by the significant heterogeneity in the anatomy of the cardiac venous system.

Case summary

We report the case of a 70-year-old woman with recurrent episodes of rest angina refractory to optimal medical therapy [Canadian Cardiovascular Society (CCS) Class IV] and inducible ischaemia in a large myocardial territory. Given the diffuse and peripheral nature of the coronary disease, the patient was considered ineligible for percutaneous or surgical revascularization and she was regarded as a good candidate for a CS occluder. Since coronary venous angiography showed the middle cardiac vein (MCV) to be at least as relevant as the CS, successful implantation of two devices, one in the CS and the second in the MCV, was performed. At 6-month follow-up, the patient reported a significant improvement in angina, resulting in a reduction of the CCS class from Grades IV to III.

Discussion

In patients affected by refractory angina and regarded as good candidates for Reducer implantation, a thorough comprehension of the cardiac venous pathway drainage is of pivotal importance to guarantee the therapeutic success of the procedure. In this patient, since the CS and the MCV seemed to contribute equally to coronary venous drainage, Reducer implantation in both vessels allowed to obtain a significant improvement of symptoms. The clinical effectiveness of this strategy needs to be validated in randomized clinical trials.

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.

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.

Relief of Ischemia in Ischemic Cardiomyopathy

PURPOSE OF THE REVIEW

Ischemic heart disease is among the most common causes of morbidity and mortality worldwide. In its stable manifestation, obstructing coronary artery stenoses prevent myocardial blood flow from matching metabolic needs of the heart under exercise conditions, which manifests clinically as dyspnea or chest pain. Prolonged bouts of ischemia may result in permanent myocardial dysfunction, heart failure, and eventually reduced survival. The aim of the present work is to review currently available approaches to provide relief of ischemia in stable coronary artery disease (CAD).

RECENT FINDINGS

Several pharmacological and interventional approaches have proven effectiveness in reducing the burden of ischemia in stable CAD and allow for symptom control and quality of life improvement. However, substantial evidence in favor of improved survival with ischemia relief is lacking, and recently published randomized controlled trial suggests that only selected groups of patients may substantially benefit from this approach. Pharmacological treatments aimed at reducing ischemia were shown to significantly reduce ischemic symptoms but failed to provide prognostic benefit. Myocardial revascularization is able to re-establish adequate coronary artery flow and was shown to improve survival in selected groups of patients, i.e., those with significant left main CAD or severe left ventricular dysfunction in multivessel CAD. Outside the previously mentioned categories, revascularization appears to improve symptoms control over medical therapy, but does not confer prognostic advantage. More studies are needed to elucidate the role of systematic invasive functional testing to identify individuals more likely to benefit from revascularization and to evaluate the prognostic role of chronic total occlusion recanalization.

Effects of coronary sinus Reducer implantation on oxygen kinetics in patients with refractory angina

AIMS

Refractory angina is still a major public health problem. The coronary sinus Reducer (CSR) has recently been introduced as an alternative treatment to reduce symptoms in these patients. The aim of this study was to investigate objective improvements in effort tolerance and oxygen kinetics as assessed by cardiopulmonary exercise testing (CPET) in patients suffering from refractory angina undergoing CSR implantation.

METHODS AND RESULTS

In this multicentre prospective study, patients with chronic refractory angina undergoing CSR implantation were scheduled for CPET before the index procedure and at six-month follow-up. The main endpoints of this analysis were improvements in VO2 max and in VO2 at the anaerobic threshold (AT). Clinical events and improvements in symptoms were also recorded. A total of 37 patients formed the study population. The CSR implantation procedure was successful and without complications in all. At follow-up CPET, significant improvement in VO2 max (+0.97 ml/kg/min [+11.3%]; 12.2±3.6 ml/kg/min at baseline vs 13.2±3.7 ml/kg/min, p=0.026), and workload (+12.9 [+34%]; 68±28 W vs 81±49 W, p=0.05) were observed, with non-significant differences in VO2 at the AT (9.84±3.4 ml/kg/min vs 10.74±3.05 ml/kg/min, p=0.06). Canadian Cardiovascular Society (CCS) grade improved from a mean of 3.2±0.5 to 1.6±0.8 (p<0.01), and significant benefits in all Seattle Angina Questionnaire variables were shown.

CONCLUSIONS

In patients with obstructive coronary artery disease suffering from refractory angina, the implantation of a CSR was associated with objective improvement in exercise capacity and oxygen kinetics at CPET, suggesting a possible reduction of myocardial ischaemia.

CMR for myocardial characterization in ischemic heart disease: state-of-the-art and future developments

Ischemic heart disease and its sequelae are one of the major contributors to morbidity and mortality worldwide. Over the last decades, technological developments have strengthened the role of noninvasive imaging for detection, risk stratification, and management of patients with ischemic heart disease. Cardiac magnetic resonance (CMR) imaging incorporates both functional and morphological characterization of the heart to determine presence, acuteness, and severity of ischemic heart disease by evaluating myocardial wall motion and function, the presence and extent of myocardial edema, ischemia, and scarring. Currently established clinical protocols have already demonstrated their diagnostic and prognostic value. Nevertheless, there are emerging imaging technologies that provide additional information based on advanced quantification of imaging biomarkers and improved diagnostic accuracy, therefore potentially allowing reduction or avoidance of contrast and/or stressor agents. The aim of this review is to summarize the current state of the art of CMR imaging for ischemic heart disease and to provide insights into promising future developments.

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.

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.

Feature tracking and mapping analysis of myocardial response to improved perfusion reserve in patients with refractory angina treated by coronary sinus Reducer implantation: a CMR study

Coronary sinus (CS) Reducer implantation improves myocardial perfusion and symptoms in patients with debilitating refractory angina. Its impact on myocardial remodeling remain uncertain. Aim of the present study was to assess possible impact of CS Reducer on myocardial systolic-diastolic deformation and microstructural remodeling, as assessed through cardiac magnetic resonance (CMR) feature tracking and mapping analysis. Twenty-eight consecutive patients with refractory angina underwent multiparametric stress CMR before and 4 months after CS Reducer implantation. Eight patients were excluded (6 for absence of inducible ischemia, 2 for artifacts). Modifications in 3D systo-diastolic myocardial deformation were evaluated using feature tracking analysis on rest cine images. Myocardial microstructural remodeling was assessed by native T1 mapping, cellular and matrix volume and extracellular volume fraction (ECV). Collaterally, the percentage of ischemic myocardium (ischemic burden %) and the myocardial perfusion reserve index (MPRI) were measured. After CS Reducer implantation, myocardial contractility improved (ejection fraction rose from 61 to 67%; p = 0.0079), along with longitudinal (from - 16 to - 19%; p = 0.0192) and circumferential strain (from - 18 to - 21%; p = 0.0017). Peak diastolic radial, circumferential and longitudinal strain rate did not change (p > 0.05), and no changes in native T1, ECV, cellular and matrix volume were observed. Myocardial perfusion improved, with a reduction of ischemic burden (13-11%; p = 0.0135), and recovery of intramural perfusion balance in segments with baseline ischemia (MPRi endocardial/epicardial ratio from 0.67 to 0.96; p = 0.0107). CS Reducer improves myocardial longitudinal and circumferential strain, without microstructural remodeling and no impact on diastolic proprieties.

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.

Improved Myocardial Function With Coronary Sinus Reducer in a Patient With Refractory Angina and Heart Failure With Reduced Ejection Fraction

The coronary sinus Reducer represents a novel therapeutic option with established safety and clinical benefit in the treatment of patients with refractory angina, possibly achieved by enhancing perfusion of myocardial ischemic territories. We report the first case providing insight on how improved perfusion might translate into improved myocardial function as assessed by cardiac magnetic resonance strain imaging, thus suggesting a physiological rationale to test coronary sinus Reducer in the setting of ischemic cardiomyopathy with reduced ejection fraction and adverse remodelling.

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

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