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Stent Thrombosis Causes & Presentation
Stent thrombosis, also known as abrupt vessel closure, occurs when an implanted coronary stent causes a thrombotic occlusion.1 Often, this can lead to myocardial infarction. Although it occurs in about 0.5% of patients that undergo a coronary stent procedure, it is a severe complication that has a mortality rate of up to 45% and a recurrence rate of up to 20% within 5 years of the first episode.2, 3
Nonadherence to dual antiplatelet therapy (DAPT) is the most common of acute stent thrombosis causes.4 The premature discontinuation of the DAPT within 6 months of a coronary stent implantation is associated with an increased risk of stent thrombosis.5
The high-risk population of abrupt vessel closure involves patients with diabetes mellitus or renal insufficiency. Moreover, the Duke jeopardy score, the final stent’s minimal luminal diameter, and the characteristics of the preprocedural thienopyridine administration have been shown to be involved in stent thrombosis development.1
Other predictors include ongoing inflammation and the development of neoatherosclerosis, both of which delay healing after stent implantation.6
Stent Thrombosis Classification
Different types of this complication can be classified regarding the type of underlying stent (stent material), clinical scenario, and timing after initial stent placement.1
- Underlying stent category classifications — Stent thrombosis as bare-metal stent, a first-generation drug-eluting stent (DES), and a second-generation DES
- Clinical scenario classification — Symptomatic or clinically silent
- Timing classification — Early abrupt vessel closure occurs 30 days after the initial placement, late-state stem thrombosis occurs between 1 and 12 months after the initial placement, and very late abrupt vessel closure occurs after 1 year of the initial placement
Diagnostic Workup & Differential Diagnosis
A provider should first evaluate the patient’s history, focusing on the date of the stent surgery, as most cases occur within the first 30 days of a coronary stent implantation. Later, the individual should also be evaluated through physical examination, electrocardiogram, echocardiogram, and cardiac enzymes.1
Stent Thrombosis vs Restenosis
The most common differential diagnosis is restenosis. While stent thrombosis is an acute occlusion that causes an acute coronary syndrome, restenosis is a slow and progressive process that involves the narrowing of the stent lumen due to the growth of biologically fibrous neointima around the stem, resulting in anginal symptoms.3
Stent Thrombosis Management
Management is based on nonpharmacotherapy and pharmacotherapy. Nonpharmacotherapy may involve aspiration thrombectomy, angioplasty, and additional stent implantation. Pharmacotherapy may involve the optimization of the applied antiplatelet therapy.
Nonpharmacotherapy
When an angina occurs as a consequence of stent thrombosis, the patient immediately needs an aspiration thrombectomy or angioplasty to restore the patency of the occluded vessel.1 In some cases, an additional stent must be placed, although it should be avoided as much as possible since every additional centimeter of stent implantation increases the risk of subsequent abrupt vessel closures.1
Coronary imaging, such as intravascular ultrasound (IVUS) or optical coherence tomography, helps identify the mechanisms of abrupt vessel closure, like malapposition and underexpansion, which should be treated with dilation by balloon angioplasty. The IVUS can also identify uncovered struts, which must be treated with aspiration thrombectomy plus more potent antiplatelet therapy. If the imagining indicates an in-stent neoatherosclerosis, the patient may require additional stent implantation.7
Pharmacotherapy
Dual antiplatelet therapy with aspirin and ticlopidine is currently recommended for patients undergoing stent implantation, which has a lower prevalence of stent thrombosis than therapy with aspirin alone or aspirin plus warfarin.5
Patients must be evaluated for confirmation of adherence to the prescribed antiplatelet therapy.7 In the case of therapy inefficacy, the therapy may be modified by replacing the drugs used. For example, prasugrel or ticagrelor may replace clopidogrel as more potent options.6
Complications
Complications may lead to myocardial infarction, cardiogenic shock, or death.1 Due to poor prognosis, prevention is highly important. Main prevention measures are to ensure the patient adheres to the dual antiplatelet therapy, choose an adequate stent size, and identify the expansion characteristics.4
Monitoring
Within the first 24 hours of a percutaneous coronary intervention, patients need dynamic monitoring. This procedure includes continuous monitoring of vital signs and the electrophysiologic activity of the heart.
Cardiac enzymes, such as troponin, may take time to increase with stent thrombosis.8 A finding of angina pectoris, or symptoms such as chest pain or shortness of breath, is a sign to act and treat the patient even if cardiac enzymes are still negative.8
Although less likely, abrupt vessel closure can occur at a late-stage post percutaneous coronary intervention. The outpatient follow-up includes monitoring for chest pain and shortness of breath, which can be signs. Particularly, patients with diabetes mellitus and renal failure are at higher risk of developing late stent thrombosis.3
References
1. Modi K, Soos MP, Mahajan K. Stent Thrombosis. In: StatPearls. NCBI Bookshelf version. StatPearls Publishing: 2022, June 19. Accessed October 7, 2022.
2. Moukarbel GV. Coronary stent thrombosis and mortality: Does the relationship stand the test of time? Journal of the American Heart Association. 2022;11(7):e025341. doi:10.1161/JAHA.122.025341
3. Gori T, Polimeni A, Indolfi C, et al. Predictors of stent thrombosis and their implications for clinical practice. Nature Reviews Cardiology. 2019;16(4):243-256. doi:10.1038/s41569-018-0118-5
4. Levine GN, Bates ER, Blankenship JC, et al. 2011 ACCF/AHA/SCAI guideline for percutaneous coronary intervention. Circulation. 2011;124(23):e574-e651. doi:10.1161/CIR.0b013e31823ba622
5. Kirtane AJ, Stone GW. How to minimize stent thrombosis. Circulation. 2011;124(11):1283-1287. doi:10.1161/CIRCULATIONAHA.110.976829
6. Cutlip DE. Stent thrombosis management. Cardiac Interventions Today. May/June 2015. Accessed September 20, 2022.
7. Ong DS, Jang IK. Causes, assessment, and treatment of stent thrombosis—intravascular imaging insights. Nature Reviews Cardiology. 2015;12(6):325-336. doi:10.1038/nrcardio.2015.32
8. Ge J, Yu H, Li J. Acute coronary stent thrombosis in modern era: Etiology, treatment, and prognosis. Cardiology. 2017;137(4):246-255. doi:10.1159/000464404
Francina Agosti is a freelance science and medical writer based in Canada. She holds a PhD in neuroscience and has worked in academia for 10 years. Now she writes scientific and medical articles for digital outlets and works as a scientific consultant for biotech and biopharma companies.
