|Year : 2021 | Volume
| Issue : 3 | Page : 206-211
Case series and brief review report: Excimer laser coronary atherectomy, facilitating daily complex interventional challenges
Fawaz Khalil Bardooli, Tajammul Hussain, Haitham Amin, Sadananda Shivappa, Husam A Noor
Mohammed Bin Khalifa Bin Cardiac Center, Awali, Kingdom of Bahrain
|Date of Submission||03-Dec-2020|
|Date of Acceptance||29-Aug-2021|
|Date of Web Publication||11-Oct-2021|
Dr. Fawaz Khalil Bardooli
Mohammed Bin Khalifa Bin Cardiac Center, Awali
Kingdom of Bahrain
Source of Support: None, Conflict of Interest: None
| Abstract|| |
The excimer laser has revolutionary impact on lesion preparation and chronic total occlusion outcomes. Furthermore, this technology has made huge progression in modern percutaneous intervention, especially in ones labeled as noncrossable lesions. This device has the advantage of crossing lesions that 0.14 wire pass through. The mechanism through which excimer laser coronary atherectomy (ELCA) works are photochemical, photothermal, and photomechanical. In this review cases article, we discuss the uses of ELCA in daily catheterization laboratory alone and with other plaque modification tools. We touch on acute coronary syndrome uses of ELCA, no-balloon crossing lesion, and intervening on deformed stents.
Keywords: Chronic total occlusion, excimer laser coronary atherectomy, intravascular lithotripsy, rota-ablation
|How to cite this article:|
Bardooli FK, Hussain T, Amin H, Shivappa S, Noor HA. Case series and brief review report: Excimer laser coronary atherectomy, facilitating daily complex interventional challenges. Heart Views 2021;22:206-11
|How to cite this URL:|
Bardooli FK, Hussain T, Amin H, Shivappa S, Noor HA. Case series and brief review report: Excimer laser coronary atherectomy, facilitating daily complex interventional challenges. Heart Views [serial online] 2021 [cited 2021 Dec 1];22:206-11. Available from: https://www.heartviews.org/text.asp?2021/22/3/206/328024
| Introduction|| |
As a consequence of an aging population, more complex coronary artery disease lesions are encountered. These include heavily calcified plaques, chronic total occlusion (CTO), and balloon nondilatable lesions.
An array of efficient plaque-modifying devices are available today in a cardiologist's armamentarium to overcome obstructive coronary lesions with a high calcium content such as Rota-ablation, excimer laser coronary atherectomy (ELCA), and shockwave lithotripsy. Even though these devices share the concept of lesion preparation, each one has a unique mechanism of action.
ELCA is 0.014-guidewire compatible mono-rail device. Its catheter is advanced to the lesion during the continuous saline flush, lasing commences with gentle, slow, forward traction of the catheter emitting ultraviolet (UV) pulses which have shallow penetrating depth. For noncrossable and nonexpansile lesions the highly deliverable 0.9 mm X-80 catheter is favor red with maximum fluency (energy) 80 mJ/mm2 and repetition rate 80 Hz attainable. The Excimer Laser effect is summarized in three stages: Photochemical, photo-thermal, and photo-mechanical.
In the photochemical stage, UV light pulses collide with tissue for 125 billionths of a second resulting in molecular bonds being fractured. In the second stage, the photo-thermal energy is generated by absorption of the UV waves. This creates molecular vibration in the tissue heating the intracellular matrix. This results in rapid vaporization of water and rupture of cells. The final photo-mechanical stage creates kinetic energy from the expansion and collapse of vapor bubbles which break down tissue and clearing by-products away from the tip.
Laser atherectomy has displayed efficiency in many clinical settings: Acute myocardial infarction, intracoronary thrombus, saphenous vein grafts, CTOs, under-expanded stent, in-stent restenosis, and un-crossable calcific lesions.
In this series of cases, we will discuss a variety of clinical scenarios where ELCA has facilitated the percutaneous coronary intervention (PCI) and improved the success rate.
| Clinical Presentations|| |
A 65-year-old female with a history of hypertension, dyslipidemia, and peripheral vascular disease. She underwent PCI to right coronary artery (RCA) in July 2015 with a drug-eluting stent for stable angina symptoms. Recently, she presented with a recurrence of angina and a positive Treadmill stress test. Her echo revealed preserved left ventricular systolic function with no valvular disease. Diagnostic angiogram revealed occluded RCA at the mid-stent segment. Faint distal RCA was visualized through right ventricular collaterals [Figure 1]a and [Figure 1]b. An attempt failed to cross the lesion with any balloon.
|Figure 1: PCI to CTO RCA, where no gear traverse the proximal cap. (a and b) Occluded RCA. (c) Fielder XT wire crossed the CTO RCA. (d) Laser tracking the wire. (e) Postlaser flow establishment. (f) Final results poststenting. PCI: Percutaneous coronary intervention, CTO: chronic total occlusion, RCA: Right coronary artery|
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She was brought back for an attempt with laser atherectomy. The occlusion was crossed with fielder XT with microcatheter Finecross MG Terumo support [Figure 1]c. Unfortunately, the Finecross could not pass the lesion and neither did the smallest balloon. Excimer laser, 0.9 mm was used, 60 mJ/mm2 and pulse rate of 40/s was used [Figure 1]d. Significant flow was achieved postELCA runs [Figure 1]e. This facilitated stent delivery and deployment after serial dilatation with noncompliant balloons. Good angiographic results and lumen gain were obtained at the end [Figure 1]f.
A 58-year-old male with long-standing dyslipidemia and hypertension, presented with unstable angina. He underwent complex PCI and stenting to proximal RCA CTO 4 weeks back with Rota-ablation. There was significant stent under-expansion due to underlying deep wall calcification which was not amenable to the upfront Rota-ablation 1.5 burr [Figure 2]a and [Figure 2]c.
|Figure 2: Optimization of under-expanded stent deployment in RCA. (a and c) Obvious under-expanded stent in severe calcification vessel (white arrow) with severe mid RCA disease. (b) Calcified lesion behind the stent resistant to noncompliant balloon inflation (arrowhead). (d) PostELCA run with contrast. (e) No waste on balloon after ELCA (arrowhead). (f) Final result. RCA: Right coronary artery, ELCA: Excimer laser coronary atherectomy|
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He was booked for another intervention to optimize the stent expansion with laser and treat the distal posterolateral branch disease. A brief trial to dilate the stent with noncompliant balloon failed [Figure 2]b and hence, multiple 0.9 mm excimer Laser runs were delivered to the under expanded stent segment with both saline and contrast flush. This broke the calcium behind the stent and facilitated the expansion of the stent with non-compliant balloons [Figure 2]d and [Figure 2]e. Distal RCA was treated again with laser and Rota-ablation burr 1.5 (RASER). Distal RCA was then stented.
Final good angiographic results and reconstruction of the previously occluded RCA [Figure 2]f is shown.
A 70-year-old active female, has long-standing history of hypertension and dyslipidemia. She presented with nonST-segment elevation myocardial infarction and preserved left ventricular (LV) systolic function. She had previous cypher 3.0 mm × 23 mm stent in Left anterior descending artery (LAD) implanted in 2010. The diagnostic angiogram revealed plaque rupture in the previous cypher stent with another tandem 70% critical stenosis just before the stent inflow [Figure 3]a and [Figure 3]b. An intravascular ultrasound (IVUS) run performed showed undersized stent layer with significant mal-apposition [Figure 3]c and vessel diameter being around ~4.5 mm. There was thrombus and a lipid-rich plaque rupture just proximal to the stented segment.
|Figure 3: Utility of ELCA in ACS/thrombus burden. (a and b) Hazy proximal LAD lesion with clots. (c) IVUS image showing under-expanded stent (arrow) with clots. (d and e) PostELCA and balloon dilatation. (f) The IVUS images after ELCA showed well apposed stent with resolution of the clot. ELCA: Excimer laser coronary atherectomy, IVUS: Intravascular ultrasound, ACS: Acute coronary syndrome, LAD: Left anterior descending artery|
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Given the high burden of thrombus behind and within the mal-opposed stent, the decision was made to use laser 1.4 mm atherectomy (fluency rate of 40 mJ/s and total pulses of 20,000 was given). The thrombus was completely resolved and the previous stent further dilated with 4.0 mm balloon while the lesion was stented with 3.5 mm × 28 mm and postdilated with 4.5 mm noncompliant balloon. There was neither distal embolization nor no-reflow and the final result was excellent [Figure 3]d, [Figure 3]e, [Figure 3]f.
A 68-year-old male who underwent multiple PCI to proximal LAD 2006. Now he presented with ischemic LV failure. His repeated angiogram showed 3-vessel disease with occluded LAD stent and severe LCx disease and significant gradual re-narrowing of a stented coronary artery lesion (ISR) in RCA.
The heart team discussed the risk and EURO score. A staged complex multi-vessel PCI was performed. Angiographically, the LAD was heavily calcified with severe ISR yet with had TIMI 3 flow. The distal LAD was diffusely diseased and tapering down [Figure 4]a. IVUS analysis preintervention revealed severe intimal hyperplasia within the under-expanded stent at the distal segment in the LAD stent [Figure 4]c. The distal LAD reference diameter is 2.5 mm, while the proximal reference vessel diameter was 3.5 mm. There was moderate calcification which was <180° arc. Excimer laser was applied to the entire stent, 60j/second total of 21.600 pulses using saline media initially and contrast media later. Subsequently, 3.0 and 3.5 NC balloons managed to cross the under-expanded segment and oppose the stent. Postintervention IVUS evaluation performed after the ELCA runs revealed the absence of intimal hyperplasia and better apposition of the second stent struts [Figure 4]d. Finally, drug-coated balloon was used to treat the stent segment to avoid another layer of stent [Figure 4]b. The final result was great with TIMI 3 flow.
|Figure 4: Intimal hyperplasia with under-expanded stent. (a) Significant disease seen in the proximal LAD. (c) The IVUS images clearly demonstrate the under-expanded stent (arrow head) and the intimal hyperplasia (arrow). This beautifully demonstrated postintervention (b and d). IVUS: Intravascular ultrasound, LAD: Left anterior descending artery|
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| Discussion|| |
In the first case, the challenge was to manage crossing the ISR-CTO after wiring. CTOs as a result of ISR constitute 5%–25% of all CTO treated percutaneously. These CTO's are associated with lower procedural success rates and higher restenosis rates than non-ISR CTOs. The previous stent allows visualization of the anatomic course of the vessel; however, layered fibrous tissue can hinder correct wire advancement into the stent lumen and may result in wire penetration into the sub-intimal space through the stent struts. Despite the fact that the wire crossed the lesion antegrade successfully, there was no balloon traversing this heavy calcified CTO proximal cap. In fact, multiple techniques failed to cross this lesion, such as anchoring in a branch or use of guide extension catheter. The ELCA 0.9 used penetrated the proximal cap creating a pilot hole. Once the calcium islands were fractured, the lesion was amenable to expansion with different balloons. A success rate of 86%–90% for ELCA in CTO cases has been reported.,
The treatment of under-expanded stent after recanalization of CTO vessel and stenting carries a high risk for future ISR or stent thrombosis (ST). This usually occurs due to the fibrotic/calcified nodules behind the deployed stent. This sort of lesions is resistant to simple balloon dilatation. Therefore, high energy ELCA with contrast mixture allows the stent to further expand at the proximal disease. In the second case, ELCA modifies the underlying resistant atheroma by delivering energy to the abluminal stent surface without disrupting the stent architecture. The success rate reaches 96% with very small complication rate.
To treat the distal RCA and PLV branch, a mild energy ELCA with saline applied followed by rotational atherectomy (RA) to completely de-bulk the calcific nature of this vessel (previous CTO). This case demonstrates the concept of the RASER (RA + Laser) approach to the calcific lesion, either as adjunctive therapy in the distal RCA or as bailout after stenting in the proximal RCA.
Acute coronary syndrome (ACS) contributed to the major bulk of daily percutaneous interventions. The third case demonstrates the utility of laser in ACS patients with a high thrombus burden. ELCA has shown not only to reduce the thrombus but also reduces the stenosis degree by 30% and increases TIMI flow by 1.6., ELCA reacts with thrombus through the high absorption spectrum characteristic of hemoglobin, the content of the thrombus. This vaporizes the thrombus and acts as local thrombolysis.
On the other hand, ELCA alters the platelet function. It decreases platelet aggregation and reduces platelet force development capability ("stunned platelets"). While the reduction in platelet aggregation is dose dependent (most pronounced at higher energy levels such as 60 mJ/mm), platelet force development reduction is not fully understandable. Plausible explanations include the mechanical (acoustic) effect of ELCA creating cavitation within the thrombus structure and or destruction in the GPIIBIIIA receptors in addition to the thermal effect.
In the treatment of in-stent restenosis with intimal hyperplasia, interventionists are faced with the challenge of the safety of reduction of intimal hyperplasia. ELCA was shown to be safe and superior to PTCA only.
ELCA + PTCA improved lumen dimensions by a combination of tissue ablation, tissue extrusion, and additional stent expansion. Luminal gain after treatment with ELCA for ISR might be achieved by a combination of neointimal tissue extrusion and stent expansion by disrupting the plaque behind the stent struts. Furthermore, the under-expanded stent due to heavy calcification was elaborated in Lee et al.
It has been shown that ELCA is effective for stent under-expansion disrupting peri-stent calcium assessed by OCT. Treating patient with ELCA seems to be safe and effective to minimize the risk of coronary dissections and subsequent bailout stenting. Moreover, the number of dissections after PCI tended to be less.
| Conclusion|| |
Failure to expand a coronary stenosis adequately or optimize a stent deployment is often associated with technical failure, incomplete revascularization, and complications. ELCA has not only contributed to the de-bulking of stable plaque in the vessel behind the stent but also reduces complications in acute unstable plaque presentation.
ELCA, with the use of contrast agent, achieves high-pressure pulse. This technique was able to cause multiple calcium fractures and subsequent dramatic enhancement of plaque compliance. In addition, the use of other debulking devices (Rota-ablation/Lithotripsy) in combination with ELCA has been reported to have better outcomes.
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
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]