Coronary stent selection and optimal course of dual antiplatelet therapy in patients at high bleeding or thrombotic risk: navigating between limited evidence and clinical concerns

The High Bleeding Risk Patient with Coronary Artery Disease

Out-of-hospital bleeding is a common complication after percutaneous coronary intervention (PCI) due to the concomitant need for dual antiplatelet therapy. A significant proportion of patients undergoing PCI carry specific clinical characteristics posing them at high bleeding risk (HBR), increasing the risk of hemorrhagic complications secondary to antithrombotic therapy. Identifying patients at HBR and adjust antithrombotic therapy accordingly to optimize treatment benefits and risk is a challenge of modern cardiology. Recently, multiple definitions and tools have been provided to help clinicians with prognostic stratification and treatment decision making in this subgroup.

Antithrombotic Therapy for Percutaneous Cardiovascular Interventions: From Coronary Artery Disease to Structural Heart Interventions

Percutaneous cardiovascular interventions have changed dramatically in recent years, and the impetus given by the rapid implementation of novel techniques and devices have been mirrored by a refinement of antithrombotic strategies for secondary prevention, which have been supported by a significant burden of evidence from clinical studies. In the current manuscript, we aim to provide a comprehensive, yet pragmatic, revision of the current available evidence regarding antithrombotic strategies in the domain of percutaneous cardiovascular interventions. We revise the evidence regarding antithrombotic therapy for secondary prevention in coronary artery disease and stent implantation, the complex interrelation between antiplatelet and anticoagulant therapy in patients undergoing percutaneous coronary intervention with concomitant atrial fibrillation, and finally focus on the novel developments in the secondary prevention after structural heart disease intervention. A special focus on treatment individualization is included to emphasize risk and benefits of each therapeutic strategy.

Prospective randomized trial of paclitaxel-coated balloon versus bare-metal stent in high bleeding risk patients with de novo coronary artery lesions

BACKGROUND

In patients with high bleeding risk, percutaneous coronary intervention is still debated. This study compared 9-month angiographic and physiologic results in patients with high bleeding risk and de novo coronary lesions treated with either paclitaxel-coated balloon (PCB) or bare-metal stent (BMS).

PATIENTS AND METHODS

A total of 40 patients (40 lesions) with high bleeding risk who underwent successful balloon angioplasty with fractional flow reserve (FFR) after balloon angioplasty more than 0.80 were randomized 1: 1 to treatment with PCB versus BMS. Dual antiplatelet therapy was limited to 1 month after the procedure.

RESULTS

Baseline clinical and lesional characteristics were well balanced between the two groups. There was no significant difference in the postprocedural FFR (0.87 ± 0.06 in PCB vs. 0.89 ± 0.06 in BMS, P = 0.254). At 9 months, late luminal loss was significantly lower in the PCB group (0.2 ± 0.3 vs. 1.2 ± 0.8 mm, P < 0.001). Restenosis only occurred in the BMS group (0 vs. 25.0%, P = 0.049).

CONCLUSION

In patients with high bleeding risk, FFR-guided PCB treatment showed superior efficacy in terms of angiographic and physiologic patency compared with BMS at mid-term follow-up with only 1 month of dual antiplatelet therapy (Clinicaltrials.gov identifier, NCT02456402).

The optimal duration of dual antiplatelet therapy after coronary stent implantation: to go too far is as bad as to fall short

Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 inhibitor is key for secondary prevention of recurrent coronary ischemic events and stent thrombosis. For this purpose, DAPT showed superior efficacy compared to aspirin alone, but it is also associated with an increased risk of major, and potentially fatal, bleeding. Hence, while secondary prevention with aspirin monotherapy is generally maintained for an indefinite period, the duration of DAPT after the index event is still debated. Multiple trials have challenged the guideline recommended standard of care of 12 months of DAPT duration. These studies tested on one side a treatment reduction to 6 or 3 months, and on the other side an extension of treatment beyond 12 months in order to define the optimal DAPT duration maximizing the anti-ischemic protection and minimizing bleeding. In this document we sought to summarize the existing evidence from more than 18 randomized controlled trials in the field, and discuss the benefit and risks of prolonging/shortening DAPT duration. In addition, a specific focus on treatment individualization will outline the current, evidence-based, decision-making process for optimal DAPT duration selection after coronary stenting.

Organ transplantation and drug eluting stents: Perioperative challenges

Patients listed for organ transplant frequently have severe coronary artery disease (CAD), which may be treated with drug eluting stents (DES). Everolimus and zotarolimus eluting stents are commonly used. Newer generation biolimus and novolimus eluting biodegradable stents are becoming increasingly popular. Patients undergoing transplant surgery soon after the placement of DES are at increased risk of stent thrombosis (ST) in the perioperative period. Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 inhibitor such as clopidogrel, prasugrel and ticagrelor is instated post stenting to decrease the incident of ST. Cangrelor has recently been approved by Food and Drug Administration and can be used as a bridging antiplatelet drug. The risk of ischemia vs bleeding must be considered when discontinuing or continuing DAPT for surgery. Though living donor transplant surgery is an elective procedure and can be optimally timed, cadaveric organ availability is unpredictable, therefore, discontinuation of antiplatelet medication cannot be optimally timed. The type of stent and timing of transplant surgery can be of utmost importance. Many platelet function point of care tests such as Light Transmittance Aggregrometry, Thromboelastography Platelet Mapping, VerifyNow, Multiple Electrode Aggregrometry are used to assess bleeding risk and guide perioperative platelet transfusion. Response to allogenic platelet transfusion to control severe intraoperative bleeding may differ with the antiplatelet drug. In stent thrombosis is an emergency where management with either a drug eluting balloon or a DES has shown superior outcomes. Post-transplant complications often involved stenosis of an important vessel that may need revascularization. DES are now used for endovascular interventions for transplant orthotropic heart CAD, hepatic artery stenosis post liver transplantation, transplant renal artery stenosis following kidney transplantation, etc. Several antiproliferative drugs used in the DES are inhibitors of mammalian target of rapamycin. Thus they are used for post-transplant immunosuppression to prevent acute rejection in recipients with heart, liver, lung and kidney transplantation. This article describes in detail the various perioperative challenges encountered in organ transplantation surgery and patients with drug eluting stents.

Comparison of Drug-Eluting and Bare Metal Stents in Patients With Chronic Kidney Disease: An Updated Systematic Review and Meta-Analysis

BACKGROUND

Drug-eluting stents (DESs) and bare metal stents (BMSs) are both recommended to improve coronary revascularization and to treat coronary artery disease in patients with chronic kidney disease (CKD). However, the potential superiority of DESs over BMSs for reducing the incidence of long-term major adverse cardiovascular events and mortality in CKD patients has not been established, and the results remain controversial. We aimed to systematically assess and quantify the total weight of evidence regarding the use of DESs versus BMSs in CKD patients.

METHODS AND RESULTS

In this systematic review and conventional meta-analysis, electronic studies published in any language until May 20, 2016, were systematically searched through PubMed, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials. We included randomized controlled trials and observational studies comparing outcomes in CKD patients with DESs versus BMSs and extracted data in a standard form. Pooled odd ratios and 95% CIs were calculated using random- and fixed-effects models. Finally, 38 studies involving 123 396 patients were included. The use of DESs versus BMSs was associated with significant reductions in major adverse cardiovascular events (pooled odds ratio 0.75; 95% CI, 0.64-0.88; P<0.001), all-cause mortality (odds ratio 0.81; 95% CI, 0.73-0.90; P<0.001), myocardial infarction, target-lesion revascularization, and target-vessel revascularization. The superiority of DESs over BMSs for improving clinical outcomes was attenuated in randomized controlled trials.

CONCLUSIONS

The use of DESs significantly improves the above outcomes in CKD patients. Nevertheless, large-sized randomized controlled trials are necessary to determine the real effect on CKD patients and whether efficacy differs by type of DES.