Contemporary management of stent thrombosis: Predictors of mortality and the role of new-generation drug-eluting stents

The Usefulness of Intracoronary Imaging in Patients with ST-Segment Elevation Myocardial Infarction

Intracoronary imaging (ICI) modalities, namely intravascular ultrasound (IVUS) and optical coherence tomography (OCT), have shown to be able to reduce major adverse cardiovascular events in patients undergoing percutaneous coronary intervention (PCI). Nevertheless, patients with ST-segment elevation myocardial infarction (STEMI) have been practically excluded from contemporary large randomized controlled trials. The available data are limited and derive mostly from observational studies. Nevertheless, contemporary studies are in favor of ICI utilization in patients who undergo primary PCI. Regarding technical aspects of PCI, ICI has been associated with the implantation of larger stent diameters, higher balloon inflations and lower residual in-stent stenosis post-PCI. OCT, although used significantly less often than IVUS, is a useful tool in the context of myocardial infarction without obstructive coronary artery disease since, due to its high spatial resolution, it can identify the underlying mechanism of STEMI, and, thus, guide therapy. Stent thrombosis (ST) is a rare, albeit a potential lethal, complication that is expressed clinically as STEMI in the vast majority of cases. Use of ICI is encouraged with current guidelines in order to discriminate the mechanism of ST among stent malapposition, underexpansion, uncovered stent struts, edge dissections, ruptured neoatherosclerotic lesions and coronary evaginations. Finally, ICI has been proposed as a tool to facilitate stent deferring during primary PCI based on culprit lesion characteristics.

A Case of Subacute Stent Thrombosis

A 67-year-old male presenting with an anterior ST-segment elevation myocardial infarction (STEMI) underwent stent placement in the left anterior descending coronary. The patient was discharged on an appropriate medical regimen containing dual antiplatelet therapy (DAPT). Four days later, the patient presented with repeat acute coronary syndrome symptomatology. Electrocardiogram demonstrated ongoing STEMI in the previously treated artery distribution. Emergency angiography revealed restenosis and total thrombotic occlusion. Post-intervention stenosis was 0% after aspiration thrombectomy and balloon angioplasty. Stent thrombosis is a high-mortality and therapeutically challenging condition requiring prepared clinicians who recognize predisposing risk factors and initiate early management.

Clinical effectiveness of thrombus aspiration during percutaneous coronary intervention for stent thrombosis in a contemporary setting

BACKGROUND

The impact of adjunctive manual thrombus aspiration (TA) in patients with stent thrombosis (ST) treated with percutaneous intervention has not been evaluated in the current era of potent P2Y12 agents and new generation drug eluting stents. We sought to assess the effect of TA using data from a large contemporary registry.

METHODS

The study population was derived from the Essex ST Investigation Registry (ESTHIR), which contains all consecutive cases of angiographically determined definite ST undergoing interventional treatment in a tertiary cardiac centre between November 2015 and June 2018. Propensity score matching was performed to match patients who underwent TA (TA group) to those who did not (n-TA group). The study endpoints were final TIMI flow and survival free of cardiovascular death (CD) or target-lesion revascularisation (TLR).

RESULTS

128 ST patients were included in the present analysis. The mean age was 65±11 years and 84% were male. 90% of the patients presented with STEMI and 85% had very late ST. Seventy-two patients (56%) underwent TA. Following propensity score matching, 30 patients were included in each study group. A higher rate of final TIMI III flow was observed in the TA group (TA vs n-TA group, 100% vs 83%), but this difference did not reach statistical significance (p=0.052). At 1000 days of follow-up, survival free of CD or TLR was not different between the two groups (p=0.8).

CONCLUSIONS

In a propensity matched population of ST patients undergoing PCI in a contemporary setting, TA was not associated with improved final TIMI flow or long-term cardiovascular outcomes.

The outcome of primary percutaneous coronary intervention in patients with stent thrombosis

BACKGROUND

Primary percutaneous coronary intervention (PCI) is a recommended management strategy for patients with de novo ST-segment elevation myocardial infarction (STEMI). Still, the efficacy of primary PCI in-stent thrombosis (ST) induced STEMI is unclear. The aim was to assess the clinical characteristics and the in-hospital outcomes of patients undergoing primary PCI for STEMI caused by acute, sub-acute, or late ST.

METHODS

A sample of hundred consecutive patients who presented with STEMI due to ST were included in this study. The angiographic evidence of a flow-limiting thrombus or total vessel occlusion (thrombolysis in myocardial infarction (TIMI) flow grade 0 to II) at the site of the previous stent implant was taken as ST. Primary PCI was performed, and all enrolled patients and in-hospital mortality were observed.

RESULTS

Male patients were 69, and the mean age was 58.9 ± 7.78 years. ST was categorized as acute in 40 patients, sub-acute in 53, and late in the remaining seven patients. Killip class III/IV was observed in 45 patients. Dissection was observed in 25, under deployment in 74, and/or malposition in 24 patients. Thrombus aspiration was performed in 97, plain old balloon angioplasty in 76, and stenting in 22 patients. Final TIMI III flow was achieved in 32 patients. During a mean hospital stay of 4.93 ± 2.46 days, the mortality rate was 27%.

CONCLUSION

In-hospital mortality after primary PCI was observed in more than 1/4th of the patients with STEMI due to ST undergoing primary PCI.

Drug-eluting stent thrombosis: current and future perspectives

Over the past 40 years, the safety and efficacy of percutaneous coronary intervention has dramatically improved by overcoming several challenges. The introduction of drug-eluting stent (DES) in particular was a major breakthrough in interventional cardiology. Compared to bare-metal stents, first-generation DES (G1-DES) has dramatically reduced the rates of in-stent restenosis and subsequent target lesion revascularization. However, major safety concerns surrounding stent thrombosis (ST) emerged with G1-DES in clinical practice as a result of the high incidences of death, myocardial infarction, and repeat revascularization associated with ST. To overcome these limitations, second-generation DES (G2-DES) has been developed with an improved stent platform with thinner strut and biocompatible durable or biodegradable polymers. Indeed, G2-DES, when compared with G1-DES, has improved clinical outcomes by reducing the risk of late thrombotic events while maintaining anti-restenotic efficacy, whereas ST still occurs, even with the use of G2-DES. This review gives an overview of pathophysiology, risk factors, and outcomes of ST after DES implantation. Additionally, we discuss the management and prevention of ST.

Clinical outcomes after percutaneous coronary intervention for early versus late and very late stent thrombosis: a systematic review and meta-analysis

Whether the clinical outcomes of stent thrombosis (ST) are different when stratified by time of occurrence remains unclear. The objective of this study was to compare the short- and long-term clinical outcomes after percutaneous coronary intervention (PCI) for early stent thrombosis (EST) versus late stent thrombosis (LST) and very late stent thrombosis (VLST). We enrolled eligible studies searched from the main electronic databases (EMBASE, PubMed, Cochrane). The primary endpoints were in-hospital, 30-day, 1-year and long-term mortality. The secondary endpoints included recurrent stent thrombosis (RST) and target vessel/lesion revascularization (TVR/TLR) during hospitalization, at 30 days, at 1 year and at long-term follow-up. A total of 23 studies with 17,592 patients were included. Compared with mortality rates of the late and very late thrombosis (LST/VLST) group, in-hospital (P = 0.004), 30-day (P < 0.00001), 1-year (P < 0.00001) and long-term mortality rates (P = 0.04) were significantly higher in the EST group. The in-hospital TVR/TLR rates were similar between the EST group and the LST/VLST group. However, a higher trend in TVR/TLR rate at 30 days and a significantly higher TVR/TLR rate at 1 year (P = 0.002) as well as at long-term follow up (P = 0.009) were found in the EST group. EST patients also trended toward higher risk of RST in both short- and long-term follow-up than LST/VLST patients, although differences were not statistically significant. After PCI treatment, patients with EST have worse clinical outcomes in both short- and long-term follow-up than patients with LST/VLST. Further studies are warranted to determine the optimal treatment strategies for EST.