Abstract
Stent underexpansion is known as a major cause of restenosis and stent thrombosis in calcified coronary lesions. We report a case of calcified nodule pretreated with excimer laser coronary angioplasty (ELCA) in acute coronary syndrome (ACS). Excimer laser use altered underlying lesion morphology such as calcified nodule and accompanied plaque and thrombus. Pretreatment of ELCA may be a useful tool to get a full expansion of the deployed stent without distal embolism for calcified nodule in ACS.
Highlights
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This is a first study that Excimer laser angioplasty is effective for calcified nodule in ACS patient.
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Excimer laser induces not only the debulking of calcified nodule but also thrombus in the culprit lesion.
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Finally round shape stent expansion could be obtained without distal embolism.
1
Introduction
The majority of acute coronary syndrome (ACS) events are the result of sudden luminal thrombosis, with 55% to 60% due to plaque rupture, 30% to 35% caused by plaque erosion, and a small portion resulting from a calcified nodule in histopathological findings . Calcified nodule consists of areas of fragmentated calcified stenosis from small calcified nodules that are surrounded by fibrin and have a small luminal thrombus. Recent advancement of imaging modalities such as intravascular ultrasound (IVUS) and optical coherence tomography (OCT) demonstrated the existence of calcified nodule in clinical practice .
Description of recent nonselective cohorts of patients requiring coronary angioplasty included 12% of severely calcified lesions . Since the calcified lesions are usually rigid, even high pressure balloon dilatation may fail to fully dilate the lesion but may lead to vessel dissection or incomplete stent deployment with its attendant risk of restenosis and stent thrombosis. Although it is less known about the clinical outcome of coronary angioplasty for calcified nodule, stent underexpansion is suggested because of the existence in superficial calcium.
Excimer laser coronary angioplasty (ELCA) is a unique revascularization modality that has a lytic effect on thrombus in addition to its debulking effect on the atherosclerotic plaque beneath the thrombus . Emission of excimer light results in enhanced antegrade TIMI flow within the infarct-related vessel . The interaction of excimer laser energy with thrombus that is typical for pulse-waved lasers includes induction of acoustic shock waves propagation onto fibrin strands leading to their fracture and dissolution. In addition, ELCA can vaporize plaque in complex coronary anatomy containing fibrous tissue, calcium, soft atheroma, or thrombus. Absorption within the atheromatous, thrombotic material results in photomechanical (breaking of chemical bond) and photothermal (increase in the target’s temperature) process that leads to vaporization and removal of irradiated lesion . We here demonstrated the effect of ELCA for vaporization of calcified nodule and thrombus in ACS.
2
Case
A 69-year-old female with hypertension, diabetes mellitus and dialysis underwent investigation for non-ST-elevation ACS. Coronary angiogram revealed a severe stenosis in the proximal right coronary artery (RCA) ( Fig. 1 ). The RCA was engaged with a 6 F JR 4.0 guide catheter (Boston Scientific, Natick, MA, USA) from the right femoral approach. After crossing RCA with a 0.014-inch guidewire (Neo’s Fielder FC, Asahi Intec., Nagoya, Japan), IVUS catheter could not be crossed this lesion. After predilatation with a 2.0/15 mm balloon (Ikazuchi, Kaneka, Osaka, Japan), IVUS and OCT examinations could be performed ( Fig. 2 ). IVUS finding showed that the culprit lesion is an eruptive, dense, calcified mass having an irregular and protruding with a convex surface. OCT finding showed a nodular calcification protruding into lumen overlying superficial calcification with red thrombus attached to the disrupted site. These two modalities identified that this culprit lesion includes calcified nodule with red thrombus. ELCA was performed with a Spectronetics CVS-300 System (Spectranetics, Colorado Springs, CO), which is a XeCl excimer laser system. A 1.4 mm concentric ELCA catheter was advanced slowly at a speed of 0.2 to 0.5 mm/s across the lesion, with standard saline flush technique applied . We started with laser energy at 45 fluence and 25 Hz. Laser energy was increased to 50 fluence and 30 Hz for two additional sequences. IVUS and OCT findings after ELCA showed that calcified nodules were disrupted and the accompanied plaque and thrombus were also vaporized. Then 3.0/18 mm integrity stent (Medtronic Inc., Minneapolis, Minnesota) was implanted, and postdilatation with 4.0/12 mm high pressure balloon (NC trek, Abbot Vascular, Abbot, Santa Clara, USA) at 20 atm was employed. Final result showed no residual stenosis ( Fig. 3 ). OCT findings showed adequate stent expansion. Clinical follow up at 10 months was uneventful, and the patient remained without angina.
