Stent fracture is associated with in-stent restenosis (ISR), thrombosis, and ischemic events. With the increasing use of the newer-generation drug-eluting stent (DES) instead of the first-generation DES or bare metal stent (BMS), stent fracture is becoming less frequent. Stent fracture is usually associated with longer stent, use of multiple stents, stent overlapping, balloon/stent overexpansion, as well as stent deployment in sites with exaggerated motion, tortuosity, or severe calcification. In most cases, stent fracture occurs in a period from months to years after implantation[1–3]. Here, we report a case of stent fracture immediately after implantation. The diagnosis was established using intravascular ultrasound (IVUS).
A 60-year-old man with documented hypertension was admitted to our hospital because of exertional chest pain for two months on March 9, 2022. Admission electrocardiogram (ECG) showed a left ventricular hypertrophy pattern with ST segment change, and serum troponin T level was normal. Coronary angiography (CAG) revealed left main (LM) true bifurcation lesions: severe stenosis in distal LM coronary artery to mid left anterior descending (LAD) coronary artery with calcification and severe stenosis in proximal left circumflex (LCX) coronary artery. There was moderate stenosis in middle right coronary artery (RCA) (Figure 1). Percutaneous coronary intervention (PCI) was conducted using the culotte-stenting technique. Briefly, after pre-dilatation with a 2.5 mm × 15 mm semi-compliant balloon (Artimes/Brosmed) in mid LAD to mid LM and proximal LCX to proximal LM, two EES (Promus Premier 2.75 mm × 38 mm, Promus Premier 3.0 mm × 32 mm; Boston Scientific, USA) were implanted sequentially from mid LAD to mid LM at 10 atmospheres (atm) with overlap between the two stents. An EES (Promus Premier 3.0 mm × 28 mm; Boston Scientific, USA) was then deployed from proximal LCX to proximal LM at 10 atm. Post-dilation was conducted with a 2.75 mm × 15 mm non-compliant balloon (Quantum) and a 3.0 mm × 15 mm non-compliant balloon (Quantum) at 12 to 16 atm in LAD to LM stents and a 3.0 mm × 15 mm non-compliant balloon (Quantum) at 12 to 16 atm in LCX to LM stent. Angioplasty was performed using the kissing balloon technique with two 3.0 mm × 15 mm non-compliant balloons (Quantum) at 14 atm simultaneously in LAD-LM and LCX-LM stents. A post-dilational angiography revealed a discontinuation of the stent strut in mid LAD. IVUS showed stent fracture at discontinuation site with calcified nodules (Figure 2). The patient was in stable condition, to prevent acute coronary syndrome (ACS), ISR, stent thrombosis (ST), and the possible need for target vessel revascularization (TVR), another EES (Promus Premier 2.75 mm × 12 mm; Boston Scientific, USA) was placed covering the stent fracture position. The mid-portion of the stented segment was then post-dilated with a 2.75 mm × 15 mm non-compliant balloon (Quantum) to a maximum of 18 atm. Post-procedural IVUS revealed good stent expansion. The final angiography showed optimal angiographic results with thromboly sis in myocardial infarction (TIMI) 3 flow (Figure 3). The patient was discharged 1 day later with prescription of dual antiplatelet therapy (aspirin and ticagrelor) and antianginal medications. At the 6-month follow-up point, the patient was asymptomatic and had a normal troponin T level (Table 1).
Table 1 -
Timeline of events during the patient’s hospitalization
|2 months before presentation
||Exertional chest pain started
|1 day after admission
||CAG revealed left main true bifurcation lesions, PCI was conducted using the culotte-stenting technique. Post-dilational angiography and IVUS revealed stent fracture of the stent strut in mid LAD, another remedial EES was placed and TIMI 3 flow was achieved
|1 day post-PCI
||The patient was discharged with a prescription of dual antiplatelet agents (aspirin and ticagrelor), atorvastatin, β-blocker and isosorbide mononitrate sustained-release tablets.
||The patient was asymptomatic, troponin T level was within normal range
CAG: coronary angiography; EES: everolimus-eluting stent; IVUS: intravascular ultrasound; LAD: left anterior descending coronary artery; PCI: percutaneous coronary intervention.
Written informed consent was obtained from the guardian of the patient for publication of this case report and accompanying images. Data sharing not applicable to this article as no datasets were generated or analyzed during the current case.
Stent fracture is one of the rare complications in the DES (especially the second-generation DES) era but a main mechanical contributor to ISR. This report described an impressive case of immediate EES fracture after stent deployment.
Estimated incidence of stent fracture varies from < 1% to 11.4% based mainly on different definitions, stent type and detection method[4,5]. In most cases, stent fracture was detected after months to years after implantation[2,6], immediate stent fracture post deployment has been rarely reported[7,8].
Stent fracture is caused by structural failure of the stent, and has been linked to longer stent, stent overlap, lesion calcification, stent overexpansion, severe angulation, and dynamic flexure[5,9]. Longer stents are prone to higher radial force during vessel contraction and bending during the systolic cycle. Stent overlap increases local axial rigidity and decreases stent conformability, and can result in hinge motion near the overlap, ultimately resulting in fracture. Calcified nodules (such as at the mid LAD stent in the index patient) alter the distribution of stress within the vessel wall, subsequent use of a high-pressure balloon in the calcified areas could damage the stent structure by augmenting the strain difference within the stent.
Worrying target lesion failure still might occur in this case, another remedial EES was placed and TIMI 3 flow was achieved. Angiography is not optimal for follow-up due to low sensitivity, IVUS or optical coherence tomography (OCT) could be helpful.
In summary, stent fracture could be disastrous but not in all cases. Clinical consequence depends on the type of stent implanted, the degree of stent fracture, and the coagulation status. Lee et al had classified stent fracture as four types: Type I: single strut fracture; Type II: multiple strut fractures; Type III: complete transverse fracture with no displacement; Type IV: complete transverse fracture with displacement. And severe stent fracture (type II to type IV) was suggested for coronary intervention. Our patient was managed in a way consistent with the recommendation above. However, Popma et al recommended management of stent fracture should be individualized based on the presence/absence of ischemia, the type of stent fracture, and the presence of risk factors for recurrence. The treatment of stent fracture is still a challenging situation due to the absence of formal recommendations or guidelines. Anyway, the present case highlighted that stent fracture could occur immediately after stent implantation, thus interventional cardiologists should consider all risk factors for stent fracture during angioplasty to minimize the risk of further complications.
Stent fracture could occur immediately after stent implantation, albeit rarely, and may or may not have immediate clinical consequence. Management should be based on the presence or absence of ischemia, the fracture type and risk factors for in-stent stenosis.
This work was supported by National Key R&D Program of China (2018YFE0103000) and Clinical Science and Technology Innovation Project of Shanghai Shenkang Hospital Development Center (SHDC12018X05).
MF wrote up the manuscript and did revisions. SC provided the case report and images. JM contributed to the discussion portion of the manuscript. JG contributed to proofreading of the manuscript. All authors contributed to answering questions raised by the reviewers. The manuscript was reviewed and approved by all authors. Each author attests to the integrity of the work.
CONFLICT OF INTEREST STATEMENT
Junbo Ge is the Editor-in-Chief of Cardiology Plus. The article was subject to the journal’s standard procedures, with peer review handled independently of the Editorial Board members and their research groups.
DATA SHARING STATEMENT
All data generated or analyzed during this study are included in this published article.
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