Stent Underexpansion Research Articles

Use of a Cutting Balloon Reduces the Incidence of Distal Embolism in Acute Coronary Syndrome Requiring Predilatation Before Stenting.

Background: Acute coronary syndrome (ACS) patients with solid lesions often require predilatation before stenting. Predilatation with high pressure may increase the risk of distal embolism, whereas direct stenting increases the risk of stent underexpansion. We recently reported that, in severely calcified lesions, using a cutting balloon (CB) can provide greater acute gain compared with other scoring balloons. Therefore, we hypothesized that predilatation with CB may reduce the incidence of distal embolism in ACS patients with solid lesions.Methods and Results: This study retrospectively analyzed data for 175 ACS patients who required predilatation, either with a conventional balloon (n=136) or CB (n=39). The occurrence of distal embolism was significantly lower in the CB than conventional balloon group (10.3% vs 32.4%, respectively; P=0.007). Multivariate analysis showed that the occurrence of distal embolism was positively associated with Thrombolysis in Myocardial Infarction (TIMI) grade and the presence of attenuated plaque, but negatively associated with the use of a CB. To support this clinical observation, we compared thrombus dispersal using a CB and non-compliant balloon in an ex vivo experimental model using a pseudo-thrombus. In this model, pseudo-thrombus dispersal was significantly smaller when a CB rather than non-compliant balloon was used (1.8±1.0% vs 2.6±1.2%, respectively; n=20, for each; P=0.002).Conclusions: In ACS patients with solid lesions that require predilatation, predilatation with a CB may reduce the incidence of distal embolism.

A Novel Strategy to Simplify the Procedures in Treating Complicated Coronary Bifurcation Lesions: From a Bench Test to Clinical Application.

BackgroundAlthough provisional stenting strategy based on jailed balloon side branch (SB) protection could be useful for high-risk bifurcation lesion in certain clinical scenarios, its complexity still gives rise to procedure complications. We proposed a novel strategy, the jailed balloon proximal optimization technique (JB-POT), to simplify the procedures in treating complex coronary bifurcation lesions (CBLs). The present study was designed to verify the safety and efficacy of JB-POT under bench testing and clinical circumstances.MethodsAfter a stent was deployed in main vessel (MV) with a balloon jailed in SB, POT and post-dilation of the stent were performed without retrieving the jailed balloon. A re-POT was performed 2 mm away from SB branching point to minimize proximal stent malapposition. The JB-POT procedure was performed on 10 samples of a silicone bifurcation bench model, and optical coherence tomography (OCT) was utilized to evaluate stent deployment. From December 2018 to July 2021, a total of 28 consecutive patients with true CBLs treated with JB-POT were enrolled. Immediate procedure results were observed, and clinical follow-ups were performed.ResultsThe bench test showed that JB-POT did not induce significant stent malapposition, underexpansion or distortion, as indexed by the malapposition rate, minimum stent area (MSA), eccentricity index and symmetry index determined through OCT. Under clinical circumstances, JB-POT did not induce significant malapposition, underexpansion or distortion. Among the 30 lesions, there was no primary endpoint event defined as SB occlusion, need to rewire the SB with a polymer-covered guide wire, or failure to retrieve a jailed wire or balloon. One rewiring event and 0 double stenting events occurred as secondary endpoint events. One patient died of heart failure in the 8th month after discharge.ConclusionsThe JB-POT protocol, which tremendously simplifies the current standard provisional stenting procedure in complicated bifurcation lesions, shows acceptability in safety and efficacy. Hence, it might become an applicable strategy for treating high-risk bifurcation lesions, especially those with multiple risked SBs.

TCTAP A-054 Shockwave Intravascular Lithotripsy as a Novel Strategy for the Treatment of Stent Underexpansion Caused by Calcified Plaques

TCTAP A-054 Shockwave Intravascular Lithotripsy as a Novel Strategy for the Treatment of Stent Underexpansion Caused by Calcified Plaques

Successful shockwave intravascular lithotripsy of an under-expanded stent after a month from primary implantation.

Successful shockwave intravascular lithotripsy of an under-expanded stent after a month from primary implantation.

Intravascular Lithotripsy for the Treatment of Stent Underexpansion: The Multicenter IVL-DRAGON Registry.

Background: Whereas the efficacy and safety of intravascular lithotripsy (IVL) have been confirmed in de novo calcified coronary lesions, little is known about its utility in treating stent underexpansion. This study aimed to investigate the impact of IVL in treating stent underexpansion. Methods and Results: Consecutive patients with stent underexpansion treated with IVL entered the multicenter IVL-Dragon Registry. The procedural success (primary efficacy endpoint) was defined as a relative stent expansion >80%. Thirty days device-oriented composite endpoint (DOCE) (defined as a composite of cardiac death, target lesion revascularization, or target vessel myocardial infarction) was the secondary endpoint. A total of 62 patients were enrolled. The primary efficacy endpoint was achieved in 72.6% of patients. Both stent underexpansion 58.5% (47.5–69.7) vs. 11.4% (5.8–20.7), p < 0.001, and the stenotic area 82.6% (72.4–90.8) vs. 21.5% (11.1–37.2), p < 0.001, measured by quantitative coronary angiography improved significantly after IVL. Intravascular imaging confirmed increased stent expansion following IVL from 37.5% (16.0–66.0) to 86.0% (69.2–90.7), p < 0.001, by optical coherence tomography and from 57.0% (31.5–77.2) to 89.0% (85.0–92.0), p = 0.002, by intravascular ultrasound. Secondary endpoint occurred in one (1.6%) patient caused by cardiac death. There was no target lesion revascularization or target vessel myocardial infarction during the 30-day follow-up. Conclusions: In this real-life, largest-to-date analysis of IVL use to manage underexpanded stent, IVL proved to be an effective and safe method for facilitating stent expansion and increasing luminal gain.

Impact of nodular calcification in patients with acute coronary syndrome (ACS) treated with primary percutaneous coronary intervention (PCI)

BackgroundCalcified plaque is thought to adversely impact outcomes after percutaneous coronary intervention (PCI). This study sought to evaluate the impact of nodular calcification in patients with acute coronary syndrome treated with primary percutaneous coronary intervention.MethodsUsing optical coherence tomography (OCT), 500 culprit plaques with calcification were analyzed from 495 acute coronary syndrome (ACS) patients on whom PCI was performed. Based on morphology, we classified calcification into two subtypes: nodular calcification and non-nodular calcification. Nodular calcification was defined as protruding mass with an irregular surface, high backscattering, and signal attenuation while non-nodular calcification was defined as an area with low backscattering heterogeneous region with a well-delineated border without protrusion into the lumen on OCT.ResultsCalcified culprit plaques were divided into nodular calcification group (n = 238) and non-nodular calcification group (n = 262). Patients with nodular calcification were older (p < 0.001) and had lower left ventricular ejection fraction (p = 0.006) compared to patients with non-nodular calcification. Minimum stent area (5.0 (3.9, 6.3) mm2 vs. 5.4 (4.2, 6.7) mm2, p = 0.011) and stent expansion (70 (62.7, 81.8) % vs. 75 (65.2, 86.6) %, p = 0.004) were significantly smaller in the nodular calcification group than in the non-nodular calcification group. Stent under-expansion was most frequent (p = 0.003) in the nodular calcification group.ConclusionThis study demonstrate that the presence of nodular calcification is associated with a smaller minimum stent area and a higher incidence of stent under-expansion. Lesions with nodular calcification may be at risk of stent under-expansion.

Randomized evaluation of vessel preparation with orbital atherectomy prior to drug-eluting stent implantation in severely calcified coronary artery lesions: Design and rationale of the ECLIPSE trial

Severe coronary artery calcification has been associated with stent underexpansion, procedural complications, and increased rates of early and late adverse clinical events in patients undergoing percutaneous coronary intervention. To date, no lesion preparation strategy has been shown to definitively improve outcomes of percutaneous coronary intervention for calcified coronary artery lesions. ECLIPSE (NCT03108456) is a prospective, randomized, multicenter trial designed to evaluate two different vessel preparation strategies in severely calcified coronary artery lesions. The routine use of the Diamondback 360 Coronary Orbital Atherectomy System is compared with conventional balloon angioplasty prior to drug-eluting stent implantation. The trial aims to enroll approximately 2000 subjects with a primary clinical endpoint of target vessel failure, defined as the composite of cardiac death, target vessel-related myocardial infarction, or ischemia-driven target vessel revascularization assessed at 1 year. The co-primary endpoint is the acute post-procedural in-stent minimal cross-sectional area as assessed by optical coherence tomography in a 500-subject cohort. Enrollment is anticipated to complete in 2022 with total clinical follow-up planned for 2 years. ECLIPSE is a large-scale, prospective randomized trial powered to demonstrate whether a vessel preparation strategy of routine orbital atherectomy system is superior to conventional balloon angioplasty prior to implantation of drug-eluting stents in severely calcified coronary artery lesions.

Use of rotational atherectomy for treatment of in-stent restenosis with coronary double-mesh stent underexpansion. Case report

Treatment of in-stent restenosis lesions, especially calcified lesions, with stent underexpansion, generally requires more complex techniques, such as rotational atherectomy. The case reported is a male patient with a 99% in-stent focal restenosis lesion at the origin of the first diagonal branch, where two stents were implanted 14 years ago. After failure of balloon angioplasty alone, ablation of the plaque and part of the stent struts was performed using the rotational atherectomy technique, which allowed the implantation of a new stent which was totally expanded.

Microvascular and Prognostic Effect in Lesions With Different Stent Expansion During Primary PCI for STEMI: Insights From Coronary Physiology and Intravascular Ultrasound.

BackgroundWhile coronary stent implantation in ST-elevation myocardial infarction (STEMI) can mechanically revascularize culprit epicardial vessels, it might also cause distal embolization. The relationship between geometrical and functional results of stent expansion during the primary percutaneous coronary intervention (pPCI) is unclear.ObjectiveWe sought to determine the optimal stent expansion strategy in pPCI using novel angiography-based approaches including angiography-derived quantitative flow ratio (QFR)/microcirculatory resistance (MR) and intravascular ultrasound (IVUS).MethodsPost-hoc analysis was performed in patients with acute STEMI and high thrombus burden from our prior multicenter, prospective cohort study (ChiCTR1800019923). Patients aged 18 years or older with STEMI were eligible. IVUS imaging, QFR, and MR were performed during pPCI, while stent expansion was quantified on IVUS images. The patients were divided into three subgroups depending on the degree of stent expansion as follows: overexpansion (>100%), optimal expansion (80%−100%), and underexpansion (<80%). The patients were followed up for 12 months after PCI. The primary endpoint included sudden cardiac death, myocardial infarction, stroke, unexpected hospitalization or unplanned revascularization, and all-cause death.ResultsA total of 87 patients were enrolled. The average stent expansion degree was 82% (in all patients), 117% (in overexpansion group), 88% (in optimal expansion), and 75% (in under-expansion). QFR, MR, and flow speed increased in all groups after stenting. The overall stent expansion did not affect the final QFR (p = 0.08) or MR (p = 0.09), but it reduced the final flow speed (−0.14 cm/s per 1%, p = 0.02). Under- and overexpansion did not affect final QFR (p = 0.17), MR (p = 0.16), and flow speed (p = 0.10). Multivariable Cox analysis showed that stent expansion was not the risk factor for MACE (hazard ratio, HR = 0.97, p = 0.13); however, stent expansion reduced the risk of MACE (HR = 0.95, p = 0.03) after excluding overexpansion patients. Overexpansion was an independent risk factor for no-reflow (HR = 1.27, p = 0.02) and MACE (HR = 1.45, p = 0.007). Subgroup analysis shows that mild underexpansion of 70%−80% was not a risk factor for MACE (HR = 1.11, p = 0.08) and no-reflow (HR = 1.4, p = 0.08); however, stent expansion <70% increased the risk of MACE (HR = 1.36, p = 0.04).ConclusionsStent expansion does not affect final QFR and MR, but it reduces flow speed in STEMI. Appropriate stent underexpansion of 70–80% does not seem to be associated with short-term prognosis, so it may be tolerable as noninferior compared with optimal expansion. Meanwhile, overexpansion and underexpansion of <70% should be avoided due to the independent risk of MACEs and no-reflow events.

Early Australian experience with intravascular lithotripsy treatment of severe calcific coronary stenosis: IVL in acute/chronic coronary syndromes.

Calcified coronary stenoses are a serious impediment to optimal stent expansion and can lead to stent failure and catastrophic adverse outcomes. We hereby present early Australian experience with intravascular lithotripsy for the treatment of calcific lesions in acute and chronic coronary syndromes. This was a single-centre retrospective study of all patients treated with intravascular lithotripsy (IVL) between October 2019 and June 2021. Patient demographics, procedural variables, and treatment safety/efficacy outcomes were evaluated. During this period, there were 40 patients and 41 coronary lesions with IVL-assisted percutaneous coronary intervention (PCI) (70% male; mean age 72.8±9.5 years). Indications for PCI were acute coronary syndromes in 25 patients (62.5%), and stable angina in 15 patients (37.5%). Upfront IVL usage occurred in 5% of cases with the rest being bailout procedures due to suboptimal initial balloon predilatation or stent underexpansion. Angiographic success (<20% residual stenosis) occurred in 37 cases (92.5%), with mean residual stenosis of 8.25%±8.5%. Two patients experienced procedural complications (5%). IVL appears to be a safe and effective modality in modifying coronary calcium to achieve optimal stent expansion in real-world practice. This device obviates the need for more complex lesion preparation strategies such as rotational or orbital atherectomy.

Novel predictors of stent under-expansion regarding calcified coronary lesions assessed by optical coherence tomography.

A previous calcium scoring system using circumferential angle, thickness, and length of coronary calcium by OCT could assist in predicting stent under-expansion. However, this scoring system only reflects the calcification distribution within a single cross-section and fails to consider the lumen's original size. The current study aims to investigate whether novel parameters to quantify calcium lesions, including calcium burden, area, and volume assessed by optical coherence tomography (OCT), could predict stent under-expansion related to calcium lesions. Consecutive patients admitted between March 10th to October 19th 2021 with calcified coronary lesions undergoing percutaneous coronary intervention (PCI) with OCT guidance were screened for inclusion. The calcium burden, area, and volume of the target lesions were measured using OCT at pre-PCI. After successful stent implantation, stent expansion at the corresponding lesions was also measured by OCT. A total of 125 patients who underwent OCT-guided PCI were included in this study. While the calcium grades by angiography failed to show a significant correlation with stent expansion, maximum and average calcium burden, maximum calcium area, and calcium volume exhibited a moderate correlation with stent expansion. According to the receiver operating characteristic curves, the optimal cutoffs of calcium volume and area for predicting stent under-expansion were 4.37 mm3 and 2.48 mm2 , respectively. Calcium burden, area, and volume by OCT are more favorable predictors of stent under-expansion given its better performance than calcium grades by angiography. Using cutoffs of calcium area and volume could identify high-risk patients of under-expansion and might guide future clinical practice.

Optical coherence tomography: evaluating the effects of stent boost subtract imaging on stent underexpansion in STEMI patients

BackgroundTo evaluate the effect of stent boost subtract (SBS) imaging on stent underexpansion during percutaneous coronary intervention (PCI) in patients with acute ST-segment elevation myocardial infarction (STEMI) by optical coherence tomography (OCT).MethodsOne hundred thirty-eight STEMI patients who underwent drug-eluting stent (DES) implantation were prospectively recruited and divided into the SBS group (69 cases) and the CAG group (69 cases) according to whether SBS was used to guide PCI. Finally, OCT was performed on all enrolled patients, and the OCT results were used as the gold standard to evaluate the impact of standard SBS technology on stent underexpansion immediately after DES implantation.ResultsSBS identified 51 patients (24%) with stent underexpansion while OCT identified 56 patients (27.2%). SBS has a sensitivity of 80%, a specificity of 96%, a positive predictive value of 88%, and a negative predictive value of 93% for identifying stent underexpansion.ConclusionCompared with OCT, SBS technology is a rapid stent imaging evaluation method that can accurately quantify the stent expansion level and is time-saving and economical.

Stent malapposition generates stent thrombosis: Insights from a thrombosis model

BackgroundCurrently, there exists differing conclusions on the role of acute stent malapposition and its role in stent thrombosis (ST). The European Association of Percutaneous Cardiovascular Interventions (EAPCI) consensus recommends that acute malapposition <0.4 mm with longitudinal extension <1 mm need not be corrected since there is no clear correlation of malapposition with adverse clinical outcomes. However, malapposition was identified as the main mechanism of ST in the Bern and PESTO registries, and one of the three leading mechanism in the PRESTIGE study. MethodsIn this study, a validated perfused benchtop thrombosis model was deployed to evaluate the role of both stent under-expansion (UE) and acute stent malapposition (MA) on thrombus formation in vitro in a controlled reproducible environment. ResultsThe results showed that UE alone did not result in acute thrombus formation, but UE together with MA did. The data suggested that a MA distance of 0.25 mm led to significant thrombus formation; and a positive correlation exists between the longitudinal extension of the MA and the thrombus volume formed. ConclusionExperiments in this in vitro model demonstrated that platelets and a thrombosis cascade were activated and developed around large segments of malapposed stent. This was significantly more thrombus formation than in the under-expanded stent region.

Intravascular lithotripsy during percutaneous coronary intervention for calcified coronary lesions: analysis of patient and procedural characteristics and clinical outcomes

Abstract Funding Acknowledgements Type of funding sources: None. Background/Introduction Coronary artery calcification is frequently encountered during percutaneous coronary intervention (PCI). It can reduce PCI success and increase intra-procedural and post-procedural complications, including stent embolization, under-expansion and mal-apposition. Intravascular lithotripsy (IVL) is a new tool developed to treat calcified coronary lesions. Purpose Retrospective analysis of all cases of intravascular lithotripsy performed within our local health district to examine patient and procedural characteristics and clinical outcomes. Methods All patients undergoing PCI with intravascular lithotripsy between September 2019-August 2021 within our local health district were analysed. Patient and procedural characteristics and clinical outcomes were recorded. Results 67 patients (50 men) were included with mean age 71.4 ± 8.7years. Risk factors prevalence included smoking (34%), hypertension (82%), dyslipidaemia (69%) and diabetes (46%). Trans-radial artery access was used in 38 patients (57%). IVL was performed most commonly in the left anterior descending artery (52%),[Figure 1]. IVL was utilised in 9 chronic total occlusions and 12 bifurcation lesions. Intracoronary (IC) imaging was performed in 59 patients (88%), intravascular ultrasound in 41(61%) and optical coherence tomography in 18 (27%). 41 (69%) patients had imaging performed pre and post IVL and post PCI. IC imaging identified 14 cases with 270º calcification arc and 45 cases with 360º arc. Nine cases (13.4%) required rotational atherectomy prior to IVL (most commonly 1.75mm burr). Mean reference vessel diameter was 3.2 ± 0.3mm. Mean lesion length was 36.3 ± 16.5mm. Mean pre-PCI stenosis was 85.5 ± 10.8%. Drug eluting stents were successfully deployed in 57 cases (85%), 10 had balloon angioplasty alone. Mean stent length was 39.2 ± 17.8mm. Mean post-PCI stenosis was 4.5 ± 13.3% (median 0%). Figure 2 shows a statistically significant increase in minimum lumen diameter and minimum lumen area post-IVL and minimal-stent-area (MSA) post-PCI. Mean stent expansion was 83%. Mean screening time 35.8 ± 17.8 minutes with mean contrast used 207.3 ± 78.7mL. No sustained arrhythmias or side-branch loss occurred. Vessel rupture was recorded in one patient necessitating urgent cardiac surgery (due to oversized balloon) and in 4 cases the IVL balloon could not cross the lesion. Conclusion Our experience shows that IVL is safe and effective and facilitates stent delivery and expansion. Intracoronary imaging is important to determine the need for calcium modification and evaluate its success prior to stent delivery and to confirm optimised stent expansion. Abstract Figure. Breakdown of PCI Artery Abstract Figure. IC Dimensions Pre/Post IVL/Post PCI

Optical coherence tomography versus angiography to guide percutaneous intervention: a real-world single center propensity-matched analysis

Abstract Funding Acknowledgements Type of funding sources: None. Background Optical coherence tomography (OCT) with its superior resolution has several benefits over coronary angiography (CA) to guide percutaneous coronary intervention (PCI). Despite the benefits of OCT in comparison with angiography, it is not widely used in developing countries like India data is limited in India specifically in all comer population to meet unmet need. Objective Here we aim to determine the clinical efficacy and safety outcomes of OCT versus CA alone in guiding PCI in all-comer patients. Methods This was a retrospective study which included 434 all comer patients which were propensity matched. These patients underwent PCI at our center between December 2018 and June 2020. The primary endpoint was MACE, a composite of cardiovascular death, repeat revascularization, stent thrombosis, recurrent ischemia and target vessel myocardial infarction (TV-MI) at 6 months. Secondary endpoint was target lesion failure (TLF), composite of stent thrombosis and in-stent restenosis. Safety endpoints were post-PCI s. creatinine and hospital stay and other outcome includes post PCI rise in CK-MB. Results A total of 217 patients were included in each group: the OCT group and conventional angiography guided PCI (angio group) after propensity matching. Compared to angio group, patients presenting with unstable angina, NSTEMI were significantly higher in the OCT group (55.7% vs 43.3%, p = 0.0095; 17.5% vs 10%, p = 0.02, respectively) while patients with STEMI were significantly low in the OCT (23.5% vs 41.5%, p = 0.00005). Number of balloons, maximum balloon size and left main interventions and contrast volume were more in OCT group than angio group (4.21 ± 1.67 vs 3.86 ± 1.76, P= 0.0034; 3.77 ± 0.63 mm vs 3.51 ± 0.52 mm,P &amp;lt; 0.0001; 24.52% vs 13.36 %,P = 0.003 and 202.53 ± 73.15 ml vs 161.91 ± 69.23 ml, P&amp;lt; 0.0001 respectively). The incidence of MACE at 6 months was numerically lower in the OCT group vs angio group but the difference was not statistically significant (15 [6.9%] vs 21 [9.7%]; p = 0.2964). No cases of TV-MI, TLF (stent thrombosis or in-stent restenosis) is observed in both the groups. Post procedure rise in CKMB was more in Angio group in comparison to OCT group (6.16 ± 31.28 ng/ml vs 39.5 ± 108.71 ng/ml, p &amp;lt; 0.001). Optimal stent expansion (&amp;gt;80%) was seen in 71.5% patients in post OCT-guided PCI. In OCT guided PCI group, OCT identified stent underexpansion in 28.5%, stent malapposition in 3.7%, stent edge dissection in 4.1%, and tissue prolapse in 10% of the patients. Conclusion In this large retrospective study, OCT guided PCI is feasible and OCT-guided PCI has tendency to improve clinical outcomes at six months follow up compared to conventional angiography guided PCI in all comer patients. Abstract Figure. central illustration Abstract Figure. Identification of PCI complications

Excimer laser technology in percutaneous coronary interventions: Cardiovascular laser society's position paper

Excimer Laser Coronary Atherectomy (ELCA) is a well-established therapy that emerged for the treatment of peripheral vascular atherosclerosis in the late 1980s, at a time when catheters and materials were rudimentary and associated with the most serious complications. Refinements in catheter technology and the introduction of improved laser techniques have led to their effective use for the treatment of a wide spectrum of complex coronary lesions, such as thrombotic lesions, severe calcific lesions, non-crossable or non-expandable lesions, chronic occlusions, and stent under-expansion. The gradual introduction of high-energy strategies combined with the contrast infusion technique has enabled us to treat an increasing number of complex cases with a low rate of periprocedural complications. Currently, the use of the ELCA has also been demonstrated to be effective in acute coronary syndrome (ACS), especially in the context of large thrombotic lesions.

Intravascular Lithotripsy for the Treatment of Underexpanded Stents: A Systematic Review and Meta-Regression Including 354 Patients from 13 Studies

Intravascular Lithotripsy for the Treatment of Underexpanded Stents: A Systematic Review and Meta-Regression Including 354 Patients from 13 Studies

ST elevation myocardial infarction due to an underexpanded stent in a heavily calcified artery.

ST elevation myocardial infarction due to an underexpanded stent in a heavily calcified artery.

Intracoronary Lithotripsy in Calcified Coronary Lesions: A Multicenter Observational Study.

The aim of this study was to evaluate the feasibility, effectiveness, and safety of coronary intravascular lithotripsy (IVL; Shockwave Medical) in the treatment of severe coronary artery calcification (CAC) in a real-world setting. Severe CAC can be an arduous obstacle in interventional cardiology, often leading to suboptimal results of percutaneous coronary interventions (PCI). Coronary IVL is a novel technique that modulates severe CAC, thereby facilitating stent implantation. In this multicenter observational study, data from 134 IVL procedures in 5 Belgian hospitals were prospectively obtained. Successful delivery of the IVL catheter was achieved in all cases but 1 (99.3%). The primary endpoint was final overall procedural success, which was obtained in 88.1% of cases, an aggregate of 92.6% in de novo lesions and 77.5% in stent underexpansion or in-stent restenosis (ISR). IVL therapy effect was considered successful by the operators in 94% of cases, with 68.7% achieving optimal and 25.3% achieving suboptimal results. The 1-month major adverse cardiovascular event rate was 3%, including 2 cardiovascular deaths (1 in-stent thrombosis and 1 coronary artery perforation). This real-world experience suggests that Shockwave IVL is a feasible, effective, and safe technique for the treatment of heavily calcified coronary lesions.

712 In-stent restenosis: how optical coherence tomography can make the difference

Abstract Aims Patient male, 38 years old, affected by hypercholesterolaemia, carotid atherosclerosis, in 2014 NSTEMI (bivascular coronary artery disease treated by angioplasty and implantation of a medicated stent in the ostial and proximal tract of the right coronary artery). In September 2021 the patient went to the emergency room of our hospital for chest pain, that comes during physical exertion, with a spontaneous regression. We performed blood tests that showed phase rise of the Hs-TNI (&amp;gt;25 000 ng/dl). The ECG showed lateral sub-endocardial ischemia and the transthoracic echocardiogram a slight reduction in ejection fraction with hypochinesia of the inferior and inferior-lateral wall. After collegial discussion, it was decided to perform a coronary angiography. Methods and results The coronary angiography showed the left coronary artery free from stenosis, with a collateral circle towards the right coronary; the right coronary showed an ostial and proximal critical in-stent restenosis with patency of the stent in the middle segment, total occlusion of the distal segment. It was decided to treat the right coronary. A guide wire was pushed into to the right coronary with difficulty and, after recanalization of the vessel, an optical coherence tomography (OCT) was performed. The OCT pointed out a homogeneous widespread neointima into the stent and an extraluminal fibrous-calcified plaque in the ostial proximal segment, which caused likely the stent under-expansion and then the stent fracture. We proceeded with angioplasty and stent implantation of the distal lesion. Due to the mechanism underlying critical in-stent restenosis (fracture of the stent) of the ostial proximal segment, we first proceed with a pre-dilatation of the lesion and then with a stent in stent implantation. Post-dilatation with a non-compliant balloon at high atm. Eventually, we found out a detail not visible before due to the ostial stenosis: the protrusion of some millimeters of the previously implanted stent in the ascending aorta; this was the cause of the difficulty in advancing the angioplasty material throughout the procedure. As a result, we had no complications. Conclusions Intracoronary imaging has stronger evidences to guide the percutaneous revascularization, especially for in-stent restenosis. Evaluation by OCT can highlight the mechanism of in-stent restenosis (biological causes/mechanical causes) and consequently it can guide the most appropriate method to perform percutaneous revascularization.