Coronary stent thrombosis
Coronary stent thrombosis or scaffold thrombosis refers to a recent acute thrombus or occlusion in a coronary segment previously treated with a coronary stent or scaffold. It is a severe complication of percutaneous coronary intervention (PCI) and a major adverse cardiovascular event.
Coronary stent thrombosis was up to 10% 1 in the past but the incidence was reduced considerably in the recent past 2.
Factors that increase the likelihood of developing coronary stent thrombosis include 1,2:
- complex lesion
- residual dissection
- implantation of an undersized coronary stent
- drug-eluting stents (1st generation)
- premature discontinuation of dual antiplatelet therapy
- diabetes mellitus
- underlying malignancy
- high platelet reactivity
Coronary stent thrombosis is associated with impaired arterial healing and uncovered struts 1.
The typical clinical presentation of stent thrombosis is that of myocardial infarction and includes the detection of a typical rise and fall in cardiac troponin above the 99th percentile URL and one following 3,4:
- symptoms of acute myocardial ischemia
- new ischemic ECG changes
- new pathological Q-waves
The following time intervals of stent or scaffold thrombosis after implantation are distinguished 1-4:
- early: <30 days (acute ≤24 hours, subacute 1-30 days)
- late: >30 days to 1 year
- very late: > 1 year
Complications of coronary stent thrombosis include 1-3:
Stent thrombosis is characterized by an acute thrombus or occlusion of a previously stented coronary segment including the adjacent 5mm proximal or distal to the stent or in a branch arising from the stented segment 4.
Causes and pathogenic mechanisms of stent thrombosis include the following 1,2:
- interruption or early dual-antiplatelet therapy
- stent malapposition or underexpansion
- impaired arterial healing/re-endothelialization and uncovered stent struts
- localized hypersensitivity reactions
- stent dismantling (in bioresorbable scaffolds)
Coronary stent thrombosis requires emergency invasive coronary angiography with repeat percutaneous coronary intervention and in this case, any additional imaging will delay treatment. However, there might be occasions, where imaging modalities will reveal findings indicating the diagnosis which have not been previously detected by other means.
Radiographic features are not different from type 1 myocardial infarction and include the following features in an ischemic pattern 3:
- new loss of viable myocardium
- new regional wall motion abnormalities
Echocardiography might detect new wall motion abnormalities.
Coronary CTA might show stent thrombosis/occlusion.
Coronary angiography within emergency repeat percutaneous coronary intervention is the modality of choice to document the diagnosis and will proof stent thrombosis following thrombectomy 4.
MRI might show signs of acute myocardial infarction corresponding to the respective coronary vascular territory including:
- cine imaging: new regional wall motion abnormalities
- T2/STIR black blood: hyperintensity indicating myocardial edema and the ‘area at risk’
- perfusion imaging: diminished or delayed uptake
- IRGE/PSIR: new subendocardial to transmural late gadolinium enhancement ± no reflow phenomenon
The radiological report should include a description of the following features based on the AHA coronary artery segment and cardiac segmentation models:
Coronary angiography/coronary CTA:
- stent occlusion
- location of the stent
- coronary artery stenoses
Echocardiography/cardiac MRI/nuclear medicine:
- regional wall motion abnormalities
- non-viable myocardium
Treatment and prognosis
The management of coronary stent thrombosis requires emergency percutaneous coronary intervention with revascularization 1.
Stent thrombosis can mimic the appearance or presentation of the following clinical conditions 1:
- 1. Torrado J, Buckley L, Durán A, Trujillo P, Toldo S, Valle Raleigh J, Abbate A, Biondi-Zoccai G, Guzmán LA. Restenosis, Stent Thrombosis, and Bleeding Complications: Navigating Between Scylla and Charybdis. (2018) Journal of the American College of Cardiology. 71 (15): 1676-1695. doi:10.1016/j.jacc.2018.02.023 - Pubmed
- 2. Byrne RA, Joner M, Kastrati A. Stent thrombosis and restenosis: what have we learned and where are we going? The Andreas Grüntzig Lecture ESC 2014. (2015) European heart journal. 36 (47): 3320-31. doi:10.1093/eurheartj/ehv511 - Pubmed
- 3. Thygesen K, Alpert JS, Jaffe AS, Chaitman BR, Bax JJ, Morrow DA, White HD. Fourth Universal Definition of Myocardial Infarction (2018). (2018) Journal of the American College of Cardiology. 72 (18): 2231-2264. doi:10.1016/j.jacc.2018.08.1038 - Pubmed
- 4. Garcia-Garcia HM, McFadden EP, Farb A, Mehran R, Stone GW, Spertus J, Onuma Y, Morel MA, van Es GA, Zuckerman B, Fearon WF, Taggart D, Kappetein AP, Krucoff MW, Vranckx P, Windecker S, Cutlip D, Serruys PW. Standardized End Point Definitions for Coronary Intervention Trials: The Academic Research Consortium-2 Consensus Document. (2018) Circulation. 137 (24): 2635-2650. doi:10.1161/CIRCULATIONAHA.117.029289 - Pubmed