Progenitor Cells for Arterial Repair: Incremental Advancements towards Therapeutic Reality

Coronary revascularization remains the standard treatment for obstructive coronary artery disease and can be accomplished by either percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery. Considerable advances have rendered PCI the most common form of revascularization and improved clinical outcomes. However, numerous challenges to modern PCI remain, namely, in-stent restenosis and stent thrombosis, underscoring the importance of understanding the vessel wall response to injury to identify targets for intervention. Among recent promising discoveries, endothelial progenitor cells (EPCs) have garnered considerable interest given an increasing appreciation of their role in vascular homeostasis and their ability to promote vascular repair after stent placement. Circulating EPC numbers have been inversely correlated with cardiovascular risk, while administration of EPCs in humans has demonstrated improved clinical outcomes. Despite these encouraging results, however, advancing EPCs as a therapeutic modality has been hampered by a fundamental roadblock: what constitutes an EPC? We review current definitions and sources of EPCs as well as the proposed mechanisms of EPC-mediated vascular repair. Additionally, we discuss the current state of EPCs as therapeutic agents, focusing on endogenous augmentation and transplantation

Very early invasive strategy in higher risk non-ST-elevation acute coronary syndrome: the RAPID NSTEMI trial

Objective To investigate whether a very early invasive strategy (IS)±revascularisation improves clinical outcomes compared with standard care IS in higher risk patients with non-ST-elevation acute coronary syndrome (NSTE-ACS). Methods Multicentre, randomised, controlled, pragmatic strategy trial of higher risk patients with NSTE-ACS, defined by Global Registry of Acute Coronary Events 2.0 score of ≥118, or ≥90 with at least one additional high-risk feature. Participants were randomly assigned to very early IS±revascularisation (<90 min from randomisation) or standard care IS±revascularisation (<72 hours). The primary outcome was a composite of all-cause mortality, new myocardial infarction or hospitalisation for heart failure at 12 months. Results The trial was discontinued early by the funder due to slow recruitment during the COVID-19 pandemic. 425 patients were randomised, of whom 413 underwent an IS: 204 to very early IS (median time from randomisation: 1.5 hours (IQR: 0.9–2.0)) and 209 to standard care IS (median: 44.0 hours (IQR: 22.9–72.6)). At 12 months, there was no significant difference in the primary outcome between the early IS (5.9%) and standard IS (6.7%) groups (OR 0.93, 95% CI 0.42 to 2.09; p=0.86). The incidence of stroke and major bleeding was similar. The length of hospital stay was reduced with a very early IS (3.9 days (SD 6.5) vs 6.3 days (SD 7.6), p<0.01). Conclusions A strategy of very early IS did not improve clinical outcomes compared with a standard care IS in higher risk patients with NSTE-ACS. However, the primary outcome rate was low and the trial was underpowered to detect such a difference

Effect of remote ischaemic conditioning on clinical outcomes in patients with acute myocardial infarction (CONDI-2/ERIC-PPCI): a single-blind randomised controlled trial.

BACKGROUND: Remote ischaemic conditioning with transient ischaemia and reperfusion applied to the arm has been shown to reduce myocardial infarct size in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). We investigated whether remote ischaemic conditioning could reduce the incidence of cardiac death and hospitalisation for heart failure at 12 months. METHODS: We did an international investigator-initiated, prospective, single-blind, randomised controlled trial (CONDI-2/ERIC-PPCI) at 33 centres across the UK, Denmark, Spain, and Serbia. Patients (age >18 years) with suspected STEMI and who were eligible for PPCI were randomly allocated (1:1, stratified by centre with a permuted block method) to receive standard treatment (including a sham simulated remote ischaemic conditioning intervention at UK sites only) or remote ischaemic conditioning treatment (intermittent ischaemia and reperfusion applied to the arm through four cycles of 5-min inflation and 5-min deflation of an automated cuff device) before PPCI. Investigators responsible for data collection and outcome assessment were masked to treatment allocation. The primary combined endpoint was cardiac death or hospitalisation for heart failure at 12 months in the intention-to-treat population. This trial is registered with ClinicalTrials.gov (NCT02342522) and is completed. FINDINGS: Between Nov 6, 2013, and March 31, 2018, 5401 patients were randomly allocated to either the control group (n=2701) or the remote ischaemic conditioning group (n=2700). After exclusion of patients upon hospital arrival or loss to follow-up, 2569 patients in the control group and 2546 in the intervention group were included in the intention-to-treat analysis. At 12 months post-PPCI, the Kaplan-Meier-estimated frequencies of cardiac death or hospitalisation for heart failure (the primary endpoint) were 220 (8·6%) patients in the control group and 239 (9·4%) in the remote ischaemic conditioning group (hazard ratio 1·10 [95% CI 0·91-1·32], p=0·32 for intervention versus control). No important unexpected adverse events or side effects of remote ischaemic conditioning were observed. INTERPRETATION: Remote ischaemic conditioning does not improve clinical outcomes (cardiac death or hospitalisation for heart failure) at 12 months in patients with STEMI undergoing PPCI. FUNDING: British Heart Foundation, University College London Hospitals/University College London Biomedical Research Centre, Danish Innovation Foundation, Novo Nordisk Foundation, TrygFonden

Procedural Results and Long-term Outcome of Chronic Total Occlusion Percutaneous Coronary Intervention in a UK Non-surgical Centre

Background: Chronic total occlusion (CTO) percutaneous coronary intervention (PCI) has evolved a great deal over recent years, with increased procedural success and lower complication rates being reported. This study aims to evaluate the feasibility, safety and success of a dedicated CTO programme in a large UK PCI centre without on-site cardiothoracic surgery facilities. Methods: Clinical and procedural data were retrospectively collected for consecutive unselected patients undergoing CTO PCI between 2015 and 2019 from the local database and regional electronic patient records. In-hospital outcomes and long-term major adverse cardiovascular events (all-cause mortality, MI, stroke and target vessel revascularisation) were recorded. Results: A total of 170 patients underwent 191 CTO procedures during the study period. The mean age was 63 ± 10 years and 80.6% of patients were male (n=137). The clinical indications were: stable chronic coronary syndromes in 88.5% (n=169) of patients; staged procedures in the context of acute coronary syndromes in 1.6% (n=3); and presentation with acute coronary syndrome in 9.9% (n=19). The procedural success rate was 50.0% (n=25) for general interventional cardiologists and 90.1% (n=127) for dedicated CTO operators. In-hospital major adverse cardiovascular events occurred once (0.5%) and interhospital transfer for emergency salvage cardiac surgery was not required. Long-term follow-up data at a median duration of 3.8 years revealed 4 (2.4%) cardiac deaths, 14 (8.3%) spontaneous MI events and 10 (5.9%) target vessel revascularisations. Conclusion: These data suggest CTO PCI using contemporary techniques is both safe and effective when undertaken in a high-volume non-surgical centre by experienced operators