REGENERATE-COBRA: A Phase II randomized sham-controlled trial assessing the safety and efficacy of intracoronary administration of autologous bone marrow-derived cells in patients with refractory angina

AIMS

The REGENERATE-COBRA trial (NCT05711849) will assess the safety and efficacy of an intracoronary infusion of autologous bone marrow-derived mononuclear cells in refractory angina patients with no revascularization options who are symptomatic despite optimal medical and device therapy.

METHODS

REGENERATE-COBRA is a single site, blinded, randomized, sham-controlled, Phase II clinical trial enrolling 110 refractory angina patients with no revascularization options who are symptomatic despite optimal medical and device therapy. Patients will be randomized to either autologous bone marrow derived-mononuclear cells or a sham procedure. Patients in the cell-treated arm will undergo a bone marrow aspiration and an intracoronary infusion of autologous bone marrow derived-mononuclear cells. Patients in the control arm will undergo a sham bone marrow aspiration and a sham intracoronary infusion. The trial's primary endpoint is an improvement in Canadian Cardiovascular Society (CCS) angina class by 2 classes between baseline and 6 months. Secondary endpoints include change in: CCS class at 12 months, myocardial ischemic burden (as measured by perfusion imaging) at 6 months, quality of life at 6 and 12 months (as measured by EQ-5D-5L, EQ-5D-VAS and Seattle Angina Questionnaire), angina frequency at 6 and 12 months, total exercise time (as measured by a modified Bruce protocol) and major adverse cardiovascular events at 6 and 12 months.

CONCLUSIONS

This is the first trial to assess the safety and efficacy of an intracoronary infusion of autologous bone marrow-derived unfractionated mononuclear cells in symptomatic refractory angina patients who have exhausted conventional therapeutic options.

Enhanced External Counterpulsation for the Treatment of Angina With Nonobstructive Coronary Artery Disease

Angina and nonobstructive coronary artery disease (ANOCA) is associated with poor outcomes and limited treatment options. Enhanced external counterpulsation (EECP) is a noninvasive treatment that involves applying external inflatable cuffs to the lower extremities to increase blood flow during diastole, followed by deflation during systole. Although EECP is approved for treatment in patients with refractory angina due to obstructive coronary artery disease, its effectiveness in treating patients with ANOCA with refractory angina is limited to small studies. We assessed the efficacy of EECP treatment in patients with ANOCA (defined as ≤50% stenosis in any major epicardial vessels) with refractory anginaby measuring changes in Canadian Cardiovascular Society (CCS) angina class, 6-minute walk test, Duke Activity Status Index (DASI), Seattle Angina Questionnaire 7 (SAQ7), and weekly anginal episodes pre-EECP and post-EECP treatment. A total of 101 patients with ANOCA with CCS class III/IV angina completed a full course of EECP treatment at 2 large EECP centers. In 101 patients with ANOCA the mean age (SD) of 60.6 (11.3) years and 62.4% of the cohort were women. We found significant improvements post-EECP treatment in CCS angina class (mean (SD) 3.4 (0.5) to 2.4 (2.9), p <0.001), 6-minute walk test (median 1200 (IQR 972 to 1411) to 1358 (1170 to 1600), p <0.001), DASI (mean (SD) 15.2 (11.6) to 31.5 (16.3), p <0.001), SAQ7 (mean (DS) 36.2 (24.7) to 31.5 (16.3), p <0.001), and weekly anginal episodes (mean (SD) 5.3 (3.5) to 2.4 (2.9), p <0.001). After EECP treatment, 71 patients (70.3%) had an improvement of ≥1 CCS angina class, including 33 (32.7%) patients improving by ≥2 CCS classes. In conclusion, in patients with ANOCA, EECP therapy reduces CCS angina class and improves exercise tolerance and capacity; and should be considered a part of optimal medical therapy.

Safety and biodistribution of XC001 (encoberminogene rezmadenovec) gene therapy in rats: a potential therapy for cardiovascular diseases

Adenovirus-mediated gene therapy holds promise for the treatment of cardiovascular diseases such as refractory angina. However, potential concerns around immunogenicity and vector dissemination from the target injected tissue require evaluation. This study was undertaken to evaluate the safety and biodistribution of XC001, a replication-deficient adenovirus serotype 5 vector expressing multiple isoforms of human vascular endothelial growth factor (VEGF), following direct administration into normal rat myocardium. Animals received the buffer formulation or increasing doses of XC001 (1 × 107, 2.5 × 108 or 2.5 × 109 viral particles). Based on in-life parameters (general health, body weights, clinical pathology, serum cardiac troponin I, plasma VEGF, and gross necropsy), there were no findings of clinical concern. On Day 8, intramyocardial administration of XC001 was associated with dose-related, left ventricular myocardial inflammation at injection sites, resolving by Day 30. XC001 DNA was not detected in blood at any time but was present at Day 8 around the site of injection and to a much lesser extent in the spleen, liver, and lungs, persisting at low levels in the heart and spleen until at least Day 91. These findings demonstrate that intramyocardial injection of XC001 is supported for use in human studies.

Nonpharmacological interventions for 'no-option' refractory angina patients

Refractory angina pectoris (RAP) defined as chronic anginal chest pain because of coronary artery disease (CAD) is a major problem. The increase in the number of patients with RAP in recent years is because of the increasing aging population and improved survival rates among patients with CAD. Management of patients with RAP is often extremely challenging. In this review, we present several interventional approaches for RAP, including device therapies, lifestyle intervention, and cell therapies. Some of these treatments are currently used in the management of RAP, whereas other treatments are under investigation.

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.

Feasibility of Spinal Cord Stimulation in Patients With Refractory Angina Pectoris and a Cardiac Implanted Electronic Device

OBJECTIVES

Five to 10% of patients with stable coronary artery disease have refractory angina pectoris (RAP). These patients are restricted in performing daily activities due to angina pectoris. Spinal cord stimulation is a last resort treatment option. A number of this patient population also has an indication for a cardiac implanted electronic device (CIED) (pacemaker or implantable cardiac defibrillator). Manufacturers of spinal cord stimulators have stated a warning that interference can occur between the spinal cord stimulator and the CIED. Consequently, only a limited number of patients with RAP and a CIED have received a spinal cord stimulator. The aim of this retrospective cohort study is to determine whether spinal cord stimulation can be safely used in patients with RAP and a CIED.

MATERIALS AND METHODS

All patients with RAP referred to our center were screened and included if 1) the patient received a spinal cord stimulator as treatment for RAP and if 2) the patient received a CIED either prior to or after spinal cord stimulator implantation. A transcutaneous electrical nerve stimulation (TENS) treadmill test was used as a screening tool to determine whether the patient was eligible for implantation of a spinal cord stimulator. Interference between the spinal cord stimulator and CIED was checked 1) after TENS treadmill test, 2) during implantation of spinal cord stimulator or CIED, 3) during mode switches of the SCS, and 4) during regular out patient follow-up.

RESULTS

In total, 22 patients had both a spinal cord stimulator and a CIED with an average follow-up duration of 44.5 months. No interference between the spinal cord stimulator and CIED was found.

CONCLUSION

Spinal cord stimulation can be safely applied in patients with a CIED provided that the CIED is checked for interference during implantation, if mode switches of the SCS occurred and once yearly after implantation according to routine follow-up.

Baseline Left Ventricle Longitudinal Strain as a Predictor for Clinical Improvement Following Coronary Sinus Reducer Implantation

Coronary sinus narrowing device (reducer) implantation has emerged as an effective treatment to improve the quality of life and functional capacity in patients suffering from disabling refractory angina. Left ventricle global longitudinal strain (LV-GLS) is a useful tool for early diagnosis of subclinical cardiac injury and an independent predictor for coronary artery disease. We aimed to investigate whether LV-GLS could help predict clinical improvement after coronary sinus reducer implantation. LV-GLS assessments were performed at baseline and 6 months after reducer implantation in consecutive patients treated for refractory angina. Patients were divided into 2 groups based on reduced (<17% absolute value) or preserved baseline LV-GLS. Clinical improvement was defined as an increase of ≥25 m in the 6-minute walk test (6MWT) at follow-up. Overall, 41 patients were included, 31 in the reduced LV-GLS group and 10 in the preserved LV-GLS group. The mean age was 68 ± 8 years, with only 2 female patients (5%). Baseline characteristics did not differ significantly between the 2 groups. Univariable analysis revealed that LV-GLS was the only significant predictor for 6MWT improvement. Baseline preserved LV-GLS reduced the likelihood of 6MWT improvement by 82% (odds ratio 0.18 [0.04 to 0.83], p = 0.029). A significant increase in 6MWT (307 ± 97 m to 343 ± 92 m, p = 0.017) was observed in the reduced LV-GLS group, compared with a decrease in the preserved LV-GLS group (378 ± 86 m to 361 ± 123 m, p = 0.651). In conclusion, reduced LV-GLS may serve as a marker for potential clinical improvement in patients with refractory angina treated with reducer. Larger clinical trials are needed to establish its role.

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.

Long-term efficacy and safety of spinal cord stimulation in patients with refractory angina pectoris

Background

The number of patients with refractory angina pectoris (RAP), associated with poor quality of life, has been steadily increasing. Spinal cord stimulation (SCS) is a last resort treatment option leading to significant improvement in quality of life over a one year follow-up. The aim of this prospective, single-centre, observational cohort study is to determine the long-term efficacy and safety of SCS in patients with RAP.

Methods

All patients with RAP who received a spinal cord stimulator from the period July 2010 up to November 2019 were included. In May 2022 all patients were screened for long-term follow-up. If the patient was alive the Seattle Angina (SAQ) and RAND-36 questionnaire were completed and if the patient had passed away cause of death was determined. The primary endpoint is the change in SAQ summary score at long-term follow-up compared to baseline.

Results

From July 2010 up to November 2019 132 patients received a spinal cord stimulator due to RAP. The mean follow-up period was 65.2 ± 32.8 months. Seventy-one patients completed the SAQ at baseline and long-term follow-up. The SAQ SS showed an improvement of 24.32U (95% confidence interval [CI]: 18.71 – 29.93; p < 0.001).

Conclusions

The main findings of the study show that long-term SCS in patients with RAP leads to significant improvement in quality of life, significant reduction in angina frequency, significantly less use of short-acting nitrates and a low risk of spinal cord stimulator related complications over a mean follow-up period of 65.2 ± 32.8 months.

Therapeutic Angiogenesis Using Autologous CD34-Positive Cells for Vascular Diseases

CD34 is a cell surface marker, which is expressed in various somatic stem/progenitor cells such as bone marrow (BM)-derived hematopoietic stem cells and endothelial progenitor cells (EPCs), skeletal muscle satellite cells, epithelial hair follicle stem cells, and adipose tissue mesenchymal stem cells. CD34+ cells in BM and peripheral blood are known as a rich source of EPCs. Thus, vascular regeneration therapy using granulocyte colony stimulating factor (G-CSF) mobilized- or BM CD34+ cells has been carried out in patients with various vascular diseases such as chronic severe lower limb ischemia, acute myocardial infarction, refractory angina, ischemic cardiomyopathy, and dilated cardiomyopathy as well as ischemic stroke. Pilot and randomized clinical trials demonstrated the safety, feasibility, and effectiveness of the CD34+ cell therapy in peripheral arterial, cardiovascular, and cerebrovascular diseases. This review provides an overview of the preclinical and clinical reports of CD34+ cell therapy for vascular regeneration.

Neuromodulation in patients with refractory angina pectoris: a review

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

Effect of cardiac shock wave therapy plus optimal medical therapy on rehospitalization in patients with severe coronary artery disease: A meta-analysis and trial sequential analysis

Objective

Several small sample-sized clinical studies have demonstrated that cardiac shock wave therapy (CSWT) might reduce the risk of rehospitalization in patients with severe coronary artery disease (CAD). However, other observational studies did not reported that clinical benefit of CSWT. Therefore, the effect of CSWT plus optimal medical therapy (OMT) on rehospitalization is still controversial.

Methods

We performed an updated meta-analysis and systematic review of randomized clinical trials (RCTs) and prospective cohort studies identified in systematic searches of Pubmed, Embase, the Cochrane library, the ClinicalTrials.gov website and Chinese SinoMed Database (up to December 2021). Primary endpoint was the rate of major adverse cardiac events (MACEs, the composite outcome of mortality, coronary artery revascularization, and rehospitalization). Meta-regression and subgroup analyses were used to identify possible contributors to between-study variances in the HDRS. Required information size (RIS) was calculated with trial sequential analysis (TSA).

Results

A total of 11 RCTs and 5 prospective cohort studies involving 1,149 patients with a mean follow-up of 10.3 months (range 3-72) months were included. Overall, CSWT plus OMT significantly decreased the rate of MACEs compared with the OMT group (RR, 0.39; 95% CI, 0.29-0.53), which was mainly attributed to markedly lower risk of rehospitalization (RR, 0.37; 95% CI, 0.27-0.51). Subgroup analysis showed that the pooled RRs for MACEs was significantly lower in studies enrolling patients with higher baseline Canadian Cardiovascular Society angina class (≥2.2) (RR, 0.36; 95% CI, 0.26-0.50) or studies with short follow-up period (followed ≤ 6 months, RR, 0.39; 95% CI, 0.24-0.64; followed 7-12 months, RR, 0.38; 95% CI, 0.26-0.54) or studies with HF with reduced ejection fraction (RR, 0.31; 95% CI, 0.13-0.72) or with preserved ejection fraction (RR, 0.40; 95% CI, 0.29-0.56). TSA showed that The RIS for MACE was 935, and the accrued information size was 577.

Conclusion

Cardiac shock wave therapy plus OMT could decrease the rate of rehospitalization among patients with severe CAD. However, this result must be interpreted with caution, for the evidence supporting the use of CSWT for severe CAD is limited by the small sample size and short follow-up period of previous studies. Larger RCTs with longer follow-up are warranted to confirm these findings.

Systematic review registration

[https://inplasy.com/], identifier [INPLASY202210103].

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.

Cardiac Shock Wave Therapy in Coronary Artery Disease: A Systematic Review and Meta-Analysis

Objective

Coronary artery disease (CAD) has been one of the leading causes of morbidity and mortality worldwide. Cardiac shock wave therapy (CSWT) is a novel and non-invasive therapy for CAD. Therefore, we conducted a systematic review and meta-analysis to evaluate the efficacy of CSWT on CAD.

Methods and results

We performed a comprehensive search of electronic databases such as PubMed, Embase, the Cochrane Library, and Wanfang Data in October 2021. The results were reported as weighted mean difference (WMD) with a 95% confidence interval (CI). Statistical heterogeneity scores were assessed with the standard Cochran's Q test and the I 2 statistic. A total of 8 randomized trials and 2 prospective cohort studies, together involving 643 patients (n = 336 CSWT and n = 307 control), were included in our study. Eight studies with 371 patients showed significantly improved rest left ventricular ejection fraction (LVEF) with CSWT as compared to that of the control group (WMD 3.88, 95% CI 1.53-6.23, p = 0.001, I 2 = 51.2%). Seven studies with 312 patients reported left ventricular internal diameter in diastole (LVIDd) were markedly decreased in the CSWT group compared to the control group (WMD -1.81, 95% CI -3.23 to -0.39, p = 0.012, I 2 = 20.3%). The summed stress score significantly favored the CSWT group (WMD -3.76, 95% CI -6.15 to -1.37, p = 0.002, I 2 = 56.8%), but there was no significant difference for the summed rest score. Our data were acquired from studies without a perceived high risk of bias, so plausible bias is unlikely to seriously affect the main findings of the current study.

Conclusion

Based on data from our present meta-analysis, CSWT was shown to moderately improve myocardial perfusion and cardiac function among patients with CAD, which would provide the clinicians with a meaningful and valuable option.

Systematic Review Registration

The meta-analysis was registered on the Open Science Framework (OSF) (https://osf.io/r2xf9).

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.

Efficacy of INtensive Treatment vs. Standard Treatment of COmpound DanshEn Dripping Pills in Refractory Angina Patients With Incomplete Revascularization (INCODER Study): Study Protocol for a Multicenter, Double-Blind, Randomized Controlled, Superiority Trial

Introduction

Patients with incomplete revascularization (ICR) tend to develop refractory angina despite optimal medical therapy. The Compound Danshen Dripping Pills (CDDP) is a widely used antianginal drug in China and is shown to significantly alleviate myocardial ischemia. Previous studies showed dose-efficacy tendency when increasing doses of CDDP. This study aims to investigate the efficacy and safety of intensive doses of CDDP in patients with refractory angina with ICR.

Methods and Analysis

The INCODER study is a multicenter, double-blind, randomized controlled, superiority trial. We plan to recruit 250 patients aged 18–85 years with a diagnosis of refractory angina with ICR. Patients will be randomized (1:1) to intensive treatment group (CDDP 20 pills three times per day) or standard treatment group (10 pills CDDP and 10 pills placebo three times per day). Patients will have a 6-week medication period and be followed up every 2 weeks. The primary endpoint is the change of total exercise time from baseline to week 6 as assessed by cardiopulmonary exercise testing (CPET). Secondary endpoints include changes in the frequency of angina, Canadian Cardiovascular Society angina class, nitroglycerin use, Seattle Angina Questionnaire scores, peak oxygen uptake (VO₂ peak) and other parameters as measured by CPET, and the levels of plasma C-reactive protein, homocysteine, and N-terminal pro-B-type natriuretic peptide. Safety events related to CDDP use will be monitored.

Ethics and Dissemination

The research had been approved by the Clinical research and laboratory animal ethics committee of the First Affiliated Hospital, Sun Yat-sen University ([2019]65). The results will be reported through peer-reviewed journals, seminars, and conference presentations.

Trial Registration Number

www.chictr.org.cn (ChiCTR2000032384). Registered on 27 April 2020.

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.

Long-term safety and efficacy of intramyocardial adenovirus-mediated VEGF-DΔNΔC gene therapy eight-year follow-up of phase I KAT301 study

In phase I KAT301 trial, intramyocardial adenovirus-mediated vascular endothelial growth factor -D^ΔNΔC (AdVEGF-D) gene therapy (GT) resulted in a significant improvement in myocardial perfusion reserve and relieved symptoms in refractory angina patients at 1-year follow-up without major safety concerns. We investigated the long-term safety and efficacy of AdVEGF-D GT. 30 patients (24 in VEGF-D group and 6 blinded, randomized controls) were followed for 8.2 years (range 6.3–10.4 years). Patients were interviewed for the current severity of symptoms (Canadian Cardiovascular Society class, CCS) and perceived benefit from GT. Medical records were reviewed to assess the incidence of major cardiovascular adverse event (MACE) and other predefined safety endpoints. MACE occurred in 15 patients in VEGF-D group and in five patients in control group (21.5 vs. 24.9 per 100 patient-years; hazard ratio 0.97; 95% confidence interval 0.36–2.63; P = 0.95). Mortality and new-onset comorbidity were similar between the groups. Angina symptoms (CCS) were less severe compared to baseline in VEGF-D group (1.9 vs. 2.9; P = 0.006) but not in control group (2.2 vs. 2.6; P = 0.414). Our study indicates that intramyocardial AdVEGF-D GT is safe in the long-term. In addition, the relief of symptoms remained significant during the follow-up.

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.

Cardiac Shock Wave Therapy Ameliorates Myocardial Ischemia in Patients With Chronic Refractory Angina Pectoris: A Randomized Trial

Background: Cardiac shock wave therapy (CSWT) is a non-invasive new option for the treatment of chronic refractory angina pectoris (CRAP). This study aimed to evaluate the safety and efficiency of CSWT in the treatment of CRAP. Methods: Eighty-seven patients with CRAP were randomly allocated into CWST group (n = 46) and Control group (n = 41). Canadian Cardiovascular Society (CCS) grade of angina pectoris, Seattle Angina Questionnaire (SAQ) score, 6-min walk test (6MWT), weekly dosage of nitroglycerin, and myocardial perfusion on D-SPECT were determined at baseline and during the follow-up period. Adverse events were also evaluated. Results: CSWT was well-tolerated in the CSWT patients. CSWT significantly improved the CCS grade, SAQ score, and 6MWT (p < 0.05). Imaging examinations showed that the ischemic area was reduced after CSWT. However, no significant changes were observed in the Control group. Conclusions: CSWT may improve the myocardial perfusion and reduce clinical symptoms without increasing adverse effects in CRAP patients. It provides a non-invasive and safe clinical therapy for CRAP patients. Clinical Trial registration: www.ClinicalTrials.gov, identifier: NCT03398096.

Management of refractory angina: an update

Despite the use of anti-anginal drugs and/or percutaneous coronary interventions (PCI) or coronary artery bypass grafting, the proportion of patients with coronary artery disease who have daily or weekly angina ranges from 2% to 24%. Refractory angina refers to long-lasting symptoms (for >3 months) due to established reversible ischaemia, which cannot be controlled by escalating medical therapy with the use of 2nd- and 3rd-line pharmacological agents, bypass grafting, or stenting. While there is uncertain prognostic benefit, the treatment of refractory angina is important to improve the quality of life of the patients affected. This review focuses on conventional pharmacological approaches to treating refractory angina, including guideline directed drug combination and dosages. The symptomatic and prognostic impact of advanced and novel revascularization strategies such as chronic total occlusion PCI, transmyocardial laser revascularization, coronary sinus occlusion, radiation therapy for recurrent restenosis, and spinal cord stimulation are also covered and recommendations of the 2019 ESC Guidelines on the Diagnosis and Management of Chronic Coronary Syndromes discussed. Finally, the potential clinical use of current angiogenetic and stem cell therapies in reducing ischaemia and/or pain is evaluated.

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.

IMPACT OF THE PLACEBO EFFECT ON SYMPTOMS, QUALITY OF LIFE AND FUNCTIONAL OUTCOMES IN ANGINA PECTORIS: A meta-analysis of randomized placebo-controlled trials

BACKGROUND

The placebo effect is a well described phenomenon in blinded studies evaluating anti-anginal therapeutics, although its impact on clinical research metrics remains unknown. We conducted a systematic review and meta-analysis to quantify the impact of placebo on endpoints of symptoms, life-quality and functional outcomes in randomized placebo-controlled trials (RCTs) of symptomatic stable coronary artery disease.

METHODS

We systematically reviewed MEDLINE, EMBASE, and the Cochrane database for double-blind RCTs of anti-angina therapeutics. Patients randomized to the placebo-arm were the study population. Main outcomes were the changes in exercise performance (exercise treadmill test [ETT] parameters), quality of life (Seattle Angina Questionnaire domains), symptoms (Canadian Cardiovascular Society angina class) and drug usage (nitroglycerin tabs/week) between baseline and following placebo. The primary outcome was ETT total duration time. Data were pooled with a random effect model.

RESULTS

Seventy-eight RCTs (83% drug-controlled, 17% procedure-controlled) were included encompassing 4,925 patients randomized to placebo. ETT total duration time was significantly improved following placebo as compared to baseline (mean [95% confidence interval]: 29.2 [20.6-37.8] seconds) with evidence of high heterogeneity (I 2 = 98%) At subgroup analysis, crossover design was associated with a smaller placebo effect on ETT performance than parallel study design (p for interaction=0.001). A significant placebo effect was observed for all secondary outcomes with overall high heterogeneity.

CONCLUSION

A substantial placebo effect was present in angina RCTs across a variety of functional and life-quality metrics. High variability in placebo effect size was present, mostly unexplained by differences in study and patient characteristics (PROSPERO CRD42019132797).

Functional Recovery after Intramyocardial Injection of Adipose-Derived Stromal Cells Assessed by Cardiac Magnetic Resonance Imaging

Aims

A major clinical concern is the continuous increase in the number of patients diagnosed with advanced coronary artery disease, ischemic heart failure, and refractory angina, and one of the most promising treatment options for these conditions is stem cell-based therapy. The aim of this study was to assess the functional improvement following intramyocardial injection of adipose-derived stromal cells, using cardiac magnetic resonance.

Methods and Results

Thirteen patients with ischemic heart failure, reduced left ventricular ejection fraction, refractory angina, and who have been disqualified from any form of direct revascularization were enrolled in the study with transthoracic autologous adipose-derived stromal cell implantation. All patients underwent cardiac magnetic resonance prior to the procedure and after 12 months of follow-up. A significant increase in stroke volume (83.1 ± 8.5 mL vs 93.8 ± 13.8 mL, p = 0.025) and stroke volume index (43.3 ± 7.6 mL/m² vs 48.7 ± 9.1 mL/m², p = 0.019), a statistical trend toward an increase in left ventricle ejection fraction (36.7 ± 13.2 vs 39.7 ± 14.9, p = 0.052), and cardiac output improvement (5.0 ± 0.7 vs 5.5 ± 0.9, p = 0.073) was observed in the patient postprocedure. Enhanced relative regional thickening was noted in the segments with adipose-derived stromal cell implantation.

Conclusions

Intramyocardial adipose-derived stromal cell implantation is a promising therapeutic option for selected, symptomatic patients with ischemic heart failure, who have preserved myocardial viability despite being unsuitable for direct revascularization.

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.

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.

Metformin protects cardiomyocytes against oxygen-glucose deprivation injury by promoting autophagic flux through AMPK pathway

Metformin has been shown to protect myocardial ischaemia/reperfusion or hypoxia/reoxygenation injury. In our current study, we investigated the effects of metformin on autophagy and its possible underlying mechanisms in in vivo myocardial infarction (MI) model and in vitro oxygen-glucose deprivation (OGD) model. A rat model of MI was made by ligating coronary artery in vivo study. Metformin (200 mg/kg/day) could improve cardiac function, prevent rats from MI-induced injury by reducing myocardial infarct size and apoptosis. Moreover, metformin furtherly promoted autophagy by increasing the protein expression of LC3-II, ATG5, ATG7 and Beclin1, and by involving AMPK pathway during MI. H9c2 cells were treated with metformin (4 mM) in vitro study to assess its effects after exposure to OGD. Metformin increased cell viability and inhibited OGD-induced LDH synthesis and cell apoptosis. Furthermore, metformin increased autophagosome formations as well as expression of autophagy-related proteins, promoted autophagic flux. In addition, metformin augmented the protein level of Bcl-2 and diminished the protein levels of Bax and cleaved caspase-3. Metformin also upregulated p-AMPK expression. Nevertheless, the above-mentioned effects of metformin on H9c2 cells were remarkably eliminated by compound C (an AMPK inhibitor). In summary, we displayed that metformin protected cardiomyocytes against OGD-induced injury and apoptosis by promoting autophagic flux through the AMPK pathway.

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.

Effect of permanent right internal mammary artery occlusion on right coronary artery supply: A randomized placebo-controlled clinical trial

Natural, nonsurgical internal mammary artery (IMA) bypasses to the coronary circulation have been shown to function as extracardiac sources of myocardial blood supply. The goal of this randomized, placebo-controlled, double-blind trial was to test the efficacy of permanent right IMA (RIMA) device occlusion on right coronary artery (RCA) occlusive blood supply and on clinical and electrocardiographic (ECG) signs of myocardial ischemia.

METHODS

This was a prospective superiority trial in 100 patients with chronic coronary artery disease randomly allocated (1:1) to RIMA vascular device occlusion (verum group) or to RIMA sham procedure (placebo group). The primary study end point was RCA collateral flow index (CFI) as obtained during a 1-minute ostial RCA balloon occlusion at baseline before and at follow-up examination 6 weeks after the trial intervention. CFI is the ratio between simultaneous mean coronary occlusive divided by mean aortic pressure both subtracted by central venous pressure. Simultaneously obtained secondary study end points were the registration of angina pectoris and quantitative intracoronary ECG ST-segment shift.

RESULTS

CFI change during the follow-up period was +0.036 ± 0.068 in the verum group and -0.021 ± 0.097 in the placebo group (P = .0011). Angina pectoris during the same RCA balloon occlusions had disappeared at follow-up in 14/49 patients of the verum group and in 4/49 patients of the placebo group (P = .0091). Simultaneous intracoronary ECG ST-segment shift change revealed diminished myocardial ischemia at follow-up in the verum group and more severe ischemia in the placebo group.

CONCLUSIONS

Permanent RIMA device occlusion augments RCA supply to the effect of diminishing clinical and electrocardiographic signs of myocardial ischemia during a brief controlled coronary occlusion.

Refractory Angina-Unsolved Problem

The article discusses pharmacologic and interventional therapeutic options for patients with refractory angina. Refractory angina refers to long-lasting symptoms (≥3 months) due to established reversible ischemia in the presence of obstructive coronary artery disease, which cannot be controlled by escalating medical therapy with second-line and third-line pharmacologic agents, bypass grafting, or stenting. Due to an aging population, increased number of comorbidities, and advances in coronary artery disease treatment, incidence of refractory angina is growing. Although the number of therapeutic options is increasing, there is a lack of randomized clinical trials that could help create recommendations for this group of patients.

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.

Ginsenoside Re Preserves Cardiac Function and Ameliorates Left Ventricular Remodeling in a Rat Model of Myocardial Infarction

Ginsenoside Re, an herbal ingredient from ginseng, has been demonstrated to protect the heart from various cardiovascular diseases. In this study, we investigated the protective effects and mechanisms of ginsenoside Re (Gin-Re) on cardiac function and left ventricular remodeling in a rat model of myocardial infarction (MI). After ligating the left anterior descending coronary artery, Wistar rats were treated with Gin-Re (135 mg/kg) by gavage everyday for 4 weeks. Serological detection showed that Gin-Re significantly inhibited myocardial injury and attenuated oxidative stress in MI rats. Echocardiographic observation showed that Gin-Re significantly improved cardiac function and prevented left ventricular dilatation induced by MI. Pathological observation found that Gin-Re significantly decreased interstitial fibrosis in the left ventricle of MI rats. Compared with the MI group, Gin-Re treatment promoted AMPKα phosphorylation, decreased TGF-β1 expression, and attenuated Smad2/3 activation. After Gin-Re treatment, the phosphorylation of FAK, PI3K p110α, and Akt was enhanced in MI rats, while PI3K p110β showed no difference compared with the MI group. These results indicate that Gin-Re may improve MI-induced cardiac dysfunction and mitigate ventricular remodeling through regulation of the AMPK/TGF-β1/Smad2/3 and FAK/PI3K p110α/Akt signaling pathways.

Long-Term (3 Years) Outcomes of Ranolazine Therapy for Refractory Angina Pectoris (from the Ranolazine Refractory Registry)

Ranolazine is approved for patients with chronic stable angina but has not been formally studied in patients with refractory angina pectoris (RAP). Patients with RAP have limited therapeutic options and significant limitations in their quality of life. The Ranolazine Refractory Angina Registry was designed to evaluate the safety, tolerability, and effectiveness of ranolazine in RAP patients in order to expand treatment options for this challenging patient population. Using an extensive prospective database, we enrolled 158 consecutive patients evaluated in a dedicated RAP clinic. Angina class, medications, major adverse cardiac events including death, myocardial infarction, and revascularization were obtained at 12, 24, and 36 months. At 3 years, 95 (60%) patients remained on ranolazine. A ≥2 class improvement in angina was seen in 48% (38 of 80 patients with known Canadian Cardiovascular Society class) of those who remained on ranolazine. Discontinuation due to side effects, ineffectiveness, cost, and progression of disease were the principle reasons for discontinuation, but primarily occurred within the first year. In conclusion, ranolazine is an effective antianginal therapy at 3-year follow-up in patients with RAP and may reduce cardiac readmission.

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.

CD34+ cell therapy significantly reduces adverse cardiac events, health care expenditures, and mortality in patients with refractory angina

Patients with refractory angina who are suboptimal candidates for further revascularization have improved exercise time, decreased angina frequency, and reduced major adverse cardiac events with intramyocardial delivery of CD34⁺ cells. However, the effect of CD34⁺ cell therapy on health care expenditures before and after treatment is unknown. We determined the effect of CD34⁺ cell therapy on cardiac‐related hospital visits and costs during the 12 months following stem cell injection compared with the 12 months prior to injection. Cardiac‐related hospital admissions and procedures were retrospectively tabulated for patients enrolled at one site in one of three double‐blinded, placebo‐controlled CD34⁺ trials in the 12 months before and after intramyocardial injections of CD34⁺ cells vs placebo. Fifty‐six patients were randomized to CD34⁺ cell therapy (n = 37) vs placebo (n = 19). Patients randomized to cell therapy experienced 1.57 ± 1.39 cardiac‐related hospital visits 12 months before injection, compared with 0.78 ± 1.90 hospital visits 12 months after injection, which was associated with a 62% cost reduction translating to an average savings of $5500 per cell therapy patient. Patients in the placebo group also demonstrated a reduction in cardiac‐related hospital events and costs, although to a lesser degree than the CD34⁺ group. Through 1 January 2019, 24% of CD34⁺ subjects died at an average of 6.5 ± 2.4 years after enrollment, whereas 47% of placebo patients died at an average of 3.7 ± 1.9 years after enrollment. In conclusion, CD34⁺ cell therapy for subjects with refractory angina is associated with improved mortality and a reduction in hospital visits and expenditures for cardiac procedures in the year following treatment.

A multi-disciplinary care pathway improves symptoms, QoL and medication use in refractory angina

Refractory angina (RA) is a growing clinical problem. Long-term mortality is better than expected and focus has shifted to improving symptoms, quality of life and psychological morbidity. We established a dedicated multi-disciplinary care pathway for patients with RA and assessed its effect on psychological outcomes, quality of life and polypharmacy. We reviewed electronic health records to capture demographics, changes in medication use, and patient-related outcome measures (Seattle Angina Questionnaire [SAQ] and Hospital Anxiety and Depression Scale) before and after enrolment. One hundred and ninety patients were referred to our service. Pre- and post-questionnaire data were available in 83 patients. Anxiety and depression scores significantly improved (p<0.05) as well as quality of life and all subcategories of the SAQ (p<0.0001). Patients were most commonly on three or four anti-anginal drugs. In patients with no demonstrable reversible ischaemia, there was a significant reduction in anti-anginal usage (mean reduction of two drugs) after completion of our pathway (p<0.025). In conclusion, a dedicated multi-disciplinary pathway for RA is associated with improvements in quality of life, mental health and polypharmacy. An ischaemia-driven method to rationalise medication may reduce polypharmacy in patients with RA, particularly in patients with no demonstrable ischaemia.

Implantation of a Coronary Sinus Reducer to Treat Refractory Angina in a 38-Year-Old with an Anomalous Left Coronary Artery and No Revascularization Options

A 38-year-old female with anomalous left coronary artery from the pulmonary artery presented with refractory angina (Canadian Cardiovascular Society [CCS] class 4). Having failed two previous internal mammary artery grafts to the left anterior descending artery and with no percutaneous revascularization options, she underwent coronary sinus reducer implantation, which improved her symptoms (CCS 0), quality of life, and corresponded to an improvement in ischemia on myocardial perfusion scanning. This case report describes an unusual case of refractory angina in the context of congenital heart disease, illustrates the benefit of this novel hourglass-shaped stent in improving ischemia, quality of life, depression and anxiety, and highlights the importance of managing these patients in multidisciplinary teams.

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

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