Plaque Prolapse after Stent Implantation in Ectasiant Coronary Artery Atherosclerotic Disease and Large Plaque Burden.

Plaque prolapse (PP) is commonly defined as tissue extrusion through the stent strut. It is not a rare event, frequently detected by intravascular ultrasound, and it is associated with stent thrombosis and adverse outcomes. We present a case of PP after stenting of the left anterior descending coronary artery. Copyright:

INTRODUCTION

Plaque prolapse (PP) is commonly defined as tissue extrusion through the stent strut;[1] it is not a rare phenomenon, especially in the case of positive coronary remodeling and vulnerable plaque with marked eccentricity and large area of necrotic core. This condition has been frequently detected by intravascular ultrasound (IVUS),[2] and some studies have shown that PP is associated with stent thrombosis and adverse outcomes. We present a case of a 38-year-old man with diffuse coronary ectasia and a significant proximal stenosis of the left anterior descending coronary artery (LAD), treated with coronary stenting with subsequent PP solved with “sandwich stent” technique.

CASE REPORT

A 38-year-old Caucasian man, cocaine addicted and obese, was admitted to the emergency department for epigastric pain radiated to the lower jaw and the left arm. The patient had a positive clinical history of hypertension treated with three antihypertensive drugs (olmesartan, nebivolol, and hydrochlorothiazide) and dyslipidemia.

His vitals on admission were as follows: blood pressure 130/80 mmHg, heart rate 70 bpm, 22 breaths per minute, and temperature 36°C. Electrocardiogram performed in the emergency department showed sinus rhythm at 70 bpm without signs of acute myocardial ischemia. Blood tests showed normal levels of cardiac enzymes (high-sensitivity troponin T < 2 ng/L, myoglobin: 40 ng/ml, and creatine kinase-MB: 0.8 ng/ml). The patient's serum creatinine level was 0.73 mg/dl (calculated estimated glomerular filtration rate: 120 ml/min); complete blood count was normal. The echocardiography examination showed normal left ventricular dimensions with preserved ejection fraction (55%) and mild left atrial dilatation.

Due to the high pretest probability of coronary artery disease (CAD), a percutaneous coronary angiography was performed which showed diffuse coronary artery ectasia of LAD and left circumflex artery and a significant stenosis of the proximal tract of the LAD, followed by an ulcerated and thrombotic plaque in the middle LAD segment associated to coronary slow flow (TIMI grade 2). A bolus of eptifibatide (180 mcg/kg) was administered intracoronary, followed by continuous intravenous infusion for 18 h, at the dosage of 20 mcg/kg/min to reduce thrombus burden. A multidisciplinary team discussed the clinical case, and a percutaneous interventional approach was decided.

On the 3rd day of hospitalization, PCI was performed through left radial artery access and an XB 3.5–6 Fr guide catheter was placed at the ostium of the left main: after positioning of a Sion Blue guidewire in the LAD, IVUS examination showed a markedly eccentric plaque with large area of necrotic core at the proximal tract of the LAD and a complex plaque at the middle segment of the LAD. IVUS measurements of the plaque at LAD proximal segment were as follows: external elastic membrane (EEM) cross-sectional area (CSA) of 46.3 mm2, vessel CSA of 46.3 mm2, lumen CSA 11.2 mm2, atheroma CSA 35.1 mm2, and plaque burden corresponded to 75% [Figure 1]. These measures guided device choice: one drug-eluting stent (DES) Synergy Megatron (Boston Scientific, Paris, FR) 4.0 mm × 16 mm was implanted in the medium tract and postdilatated with NC Quantum Apex balloon (Boston Scientific, Paris, FR) 6.0 mm × 15 mm at 20 atmospheres; another DES Synergy Megatron 4.0 mm × 16 mm was implanted in the proximal tract in an overlapping fashion and postdilatated with NC Quantum Apex balloon 6.0 mm × 15 mm at high atmospheres (22 ATM).

Figure 1

Eccentric plaque with large necrotic core

On the control angiography, a large fixed intraluminal filling defect was noted inside the stent, and grayscale IVUS examination confirmed severe PP through the stent struts due to the eccentricity and large necrotic core burden of the plaque [Figure 2]; therefore, a sandwich technique approach was performed, and another DES Synergy Megatron 4.5 mm × 24 mm was released at high pressure (18 ATM) in correspondence of the prolapsed plaque and postdilatated with an NC Quantum Apex balloon 6.0 mm × 15 mm at 20 ATM. IVUS examination revealed good stent apposition without plaque protrusion and maximum intrastent diameter and area, respectively, of 5.8 mm and 24.5 mm2 [Figure 3].

Figure 2

Plaque prolapse

Figure 3

Poststent in-stent implantation with “sandwich” technique

Pharmacological treatment with acetylsalicylic acid, prasugrel, angiotensin II receptor blocker, beta-blocker, and statin was started. The patient was discharged on the 4th day of hospitalization asymptomatic. He remained asymptomatic during 3-month follow-up.

DISCUSSION

PP is characterized by an intraluminal tissue extrusion through the stent struts, and this is easily detectable using IVUS.[2] Therefore, IVUS has the potential to recognize predictors of coronary events that are not detected by angiography.

The presence of residual plaque/thrombus prolapse is not a rare finding, and common predictors of PP are represented by positive coronary artery remodeling,[3] vulnerable plaque with marked eccentricity, large area of necrotic core, soft plaque, and large plaque burden.[345] In this setting, IVUS can characterize plaque's morphology; soft plaque appears as a zone of reduced echogenicity that can indicate also the presence of a large necrotic core within the plaque. Quantitative assessment of the surrogate true atheroma area can also be detected by IVUS measuring EEM, atheroma CSA (plaque plus media) calculated as the EEM CSA minus the lumen CSA, and plaque burden calculated as plaque plus media CSA divided by the EEM CSA.[6] Plaque protrusion is frequently detected using IVUS after stent implantation, as demonstrated in several studies that have reported a 17%–70% incidence of PP after stent implantation.[78] In an IVUS substudy of the Assessment of Dual Antiplatelet Therapy with DESs, the overall incidence of PP detected using IVUS was 38.5%, while it was 54.3% for ST-segment elevation myocardial infarction (STEMI), 46.1% for non-STEMI, 34.3% for unstable angina, and 30.6% for stable ischemic heart disease.[9] Moreover, those trials also allow us to underline the safety in the use of IVUS also in complex contexts such as acute myocardial infarction with intense thrombotic burden, even before stent placement.

Several studies have demonstrated that IVUS-guided PCI could improve the clinical outcomes in patients with DES implantation, especially for complex coronary lesions and high-risk patients. However, IVUS guidance is not routinely performed in the real-world daily practice of PCI, partly due to the increased procedural time and extra cost.

Furthermore, IVUS should contribute to guide stenting procedure by choosing a stent which could be expanded to large diameter and with a 12 peak stent design that may offer uniform lesion/vessel scaffolding. However, the Synergy Megatron has a very large stent strut area (5 mm) and therefore these characteristics may increase the risk of plaque protrusion through the strut, especially in the setting of large plaque burden as in the case presented.

However, considering the size of the coronary vessel, it was decided to use this specific type of stent with a dedicated technique and to optimize the result by IVUS evaluation.

Tissue prolapse after stent implantation has been identified as a predictor of early stent thrombosis and has been related to adverse short-term prognosis following PCI.[10] Pathological and animal studies have shown that lipid-core penetration can increase thrombogenicity, with a subsequent increase of the risk for early stent thrombosis and stent restenosis.[11] In our case, IVUS was able to characterise the plaque and to detect PP after stent implantation, allowing the best PCI strategy with optimal angiographic result.

CONCLUSION

This case highlights the key role played by IVUS during the stenting procedure of vulnerable plaque,This case highlights the key role played by IVUS during PCI of vulnerable plaque; its ability to detect complications such as PP, especially in the contest of complex CAD, is essential to guide decision-making strategy and to optimize final result.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.