Influence of Myocardial Bridge On Atherosclerotic Plaque Distribution and Characteristics Evaluated By Near-Infrared Spectroscopy Intravascular Ultrasound

Purpose This study aims to clarify whether myocardial bridge (MB) could influence atherosclerotic plaque characteristics assessed by using near-infrared spectroscopy-intravascular ultrasound (NIRS-IVUS) imaging. Methods One hundred and sixteen patients who underwent percutaneous coronary intervention (PCI) using NIRS-IVUS imaging were included. MB was defined as an echo-lucent band surrounding left anterior descending artery (LAD). In MB patients, LAD was divided into 3 segments: proximal, MB, and distal segments. In non-MB patients, corresponding 3 segments were defined based on the average length of the above segments. Segmental maximum plaque burden and lipid content derived from NIRS-IVUS imaging in the section of maximum plaque burden were evaluated in each segment. Lipid content of atherosclerotic plaque was evaluated as lipid core burden index (LCBI) and maxLCBI4mm. LCBI is the fraction of pixels indicating lipid within a region multiplied by 1000, and the maximum LCBI in any 4-mm region was defined as maxLCBI4mm. Results MB was identified in 42 patients. MB was not associated with maximum plaque burden in proximal segment. LCBI and maxLCBI4mm were significantly lower in patients with MB than those without in proximal segment. Multivariable analysis demonstrated both MB and maximum plaque burden in proximal segment to be independent predictors of LCBI in proximal segment. Conclusion Lipid content of atherosclerotic plaque assessed by NIRS-IVUS imaging was significantly smaller in patients with MB than those without. MB could be considered as a predictor of lipid content of atherosclerotic plaque when assessed by NIRS-IVUS imaging.

Refractory hypertension secondary to renal artery stenosis with a honeycomb-like structure

Background A honeycomb-like structure (HLS) is a rare abnormality characterized by a braid-like appearance. Angiograph and intravascular examination, including coherence tomography and intravascular ultrasound (IVUS), can further confirm the multiple intraluminal channels or honeycomb structure, which can also be described as looking like ‘swiss cheese’, a ‘spider web’ or a ‘lotus root’. Previous studies have mostly reported this abnormality in coronary arteries, with a few cases in renal arteries. More information about the characteristics and development of HLS is needed. Case presentation A 69-year-old Han man with resistant hypertension received abdominal enhanced computerised tomography and was revealed to have left renal artery stenosis with the possibility of left renal infarction. Renal artery angiography confirmed a 95% stenosis located in the proximal segment of the left renal artery, and the middle segment was blurred with multi-channel-like blood flow. Further IVUS was performed and identified multiple channels surrounded by fibrous tissue. It was a rare case of HLS in the renal artery secondary to the thrombus, with organisation and recanalisation. Balloon dilatation and stent implantation at the proximal segment of the left renal artery were performed successfully. Blood pressure was well controlled after the procedure. Conclusions The IVUS findings are helpful for forming interventional therapeutic strategies for HLS lesions in the renal artery.

690 Acute post-implantation enlargement of transcatheter self-expandable valve: insights from a single-centre prospective registry

Aims Transcatheter implantation of a balloon-expandable aortic valve is associated with an acute stent recoil . Conversely, the acute effects of nitinol-based stent frame- self expandable valve on post-deployment dimensions have not been reported. Accordingly, the aim of this study was to assess the occurrence and degree of acute prosthetic dimension changes after Evolute R valve implantation. Methods A total of 58 consecutive patients undergoing transcatheter aortic valve intervention (TAVI) with a widely used nitinol based self-expandable device (Evolute R, Medtronic, Minneapolis, USA) were included in this study. We measured valve diameters at three different sections: a) distal (aortic) level, b) central (annulus) level, and c) proximal (ventricular) level. Valve expansion was calculated as the difference between the diameters calculated immediately after valve deployment (A) and at the end of the procedure (B). The absolute and relative acute stent recoil were defined as B-A and (B-A)/B*100, respectively. A linear regression model was performed to test the association between the degree of valve extension, with baseline, as well as procedural characteristics. Results Final stent diameters were significantly higher compared to those achieved immediately after valve implantation in proximal (20.87±3.20 mm versus 20.37±3.27 mm, P <0.001), central (19.58±1.63 mm versus 19.12±1.75 mm, P <0.001) as well as distal (26.99±1.53 mm versus 26.41±1.57 mm, P <0.001) segments. The mean absolute and relative enlargement of the valve was respectively 0.50±0.51 mm and 2.48±2.57% in the proximal, 0.46±0.57 mm and 2.39±2.96% in the central and 0.58±0.59 mm and 2.14±2.14% in the distal segment. Among baseline and procedural characteristics assessed in the logistic regression model no association was observed between pre-dilation and valve expansion across all the segments (proximal: r2=0.004, P=0.885, central: r2=0.004, P=0.637, and distal r2=0.05, P=0.10). Of interest, post dilation affected only the expansion of the central segment (r2=0.241, P<0.001), while no association was observed for the proximal (r2=0.059, P=0.065) and distal (r2=0.0002, P=0.916) parts. The expansion of the proximal segment was associated with higher maximum/minimum diameter ratio measured by CT (r2=0.08, P=0.045), while no association was observed for the central (r2= 0.020; P=0.992) and distal (r2=1.111, P=0.683) segments. Conclusions This is the first study that documented a significant degree of post-deployment recoil of the Evolute R self-expandable valve, that was consistent across all the segments. The stent-valve expansion of the proximal segment was associated with a greater annulus dissymmetry reported by the maximum and minimum diameter ratio assessed by CT scan. However, further studies are required to assess the short and long-term time-course of self-expandable valve enlargement and the clinical relevance of this finding.

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

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 (>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.

Abstract 1122‐000192: Transient Blood Flow Reversal in The Vertebral Artery As an Embolic Protection Method During Angioplasty/Stenting

Introduction : Approximately 20% of all acute ischemic strokes occur in the vertebrobasilar (VB) circulation. Similar to carotid stenosis, symptomatic vertebral artery (VA) stenosis is associated with a high risk of stroke recurrence. The use of embolic protection devices for recanalization in the setting of carotid stenosis in order to improve clinical outcomes is well established. Recent randomised trials have failed to demonstrate improvement of clinical outcomes in VB stroke patients treated with stenting. To our knowledge, these studies did not require the use of embolic protection devices or techniques. This may be due to several factors. Firstly, since the caliber of the stenotic segment of VA is not large enough to safely allow the protection device delivery system to pass through, initial angioplasty without protection is needed. Secondly, the most common segment of VA to become stenotic is its origin, and usually after stenting of this segment, the edge of the stent is protruding into the SCA. When the angle of the VA relative to the SCA is acute, passing the filter capture catheter through this protruded stent is very difficult and dangerous. Methods : We are introducing a VA reversal blood flow technique for prevention of emboli through the VB system in the setting of symptomatic extracranial VA stenosis. In this technique, we used a balloon tip guide catheter in order to transiently occlude the proximal segment of the SCA, causing flow arrest. We then evaluated the presence of blood flow reversal in the VA. Theoretically, this induction of blood flow reversal in the VA can be considered protective because it washes the embolic particles into the distal SCA. Results : Of the 11 cases of VA origin symptomatic stenosis, 4 had desirable VA blood flow reversal after balloon occlusion trial. These patients had successful angioplasty‐stenting of the VA origin using balloon mounted stent without major complications such as ischemic stroke in the posterior circulation territory. Conclusions : This study demonstrates the feasibility of proximal SCA balloon occlusion to cause transient flow reversal in the VA during angioplasty +/‐ stenting of the proximal VA. Future studies are required to determine the effectiveness of this approach in the setting of extracranial VA stenosis due to atherosclerosis, especially at its proximal segment.

Comparative Study of Coronary Artery Proximal to Myocardial Bridge Segment

Introduction: The muscular segments which overlie the epicardial arteries are termed as myocardial bridges and the artery which travels through them are termed as tunnel arteries. These tunnel arteries get compressed during the systolic compression of the heart, thus partially or completely blocking the blood supply to the corresponding areas. Aim & Objectives: To assess the impact of these myocardial bridges on the proximal segment of the myocardial arteries. Methodology: The present study was cadaveric-based cross-sectional study. A total of 22 hearts which showed the presence of myocardial bridges were collected from two sources namely: cadaver dissections, autopsy. The hearts were clean and numbered. This was followed by fixation, dehydration, clearing, embedding, block formation, section cutting and staining. Result: The present study showed that there is a significant thickening in the tunica intima of the proximal to bridge segment of the coronary artery. The present study also noted that there is a marked thinning of the tunica media of the same segment. Conclusion: The present study concludes that there is a marked hyperplasia in the proximal segment of the myocardial bridges under tunica intima.

Intussusception Presenting as Rectal Prolapse

Intussusception is the invagination of a segment of the intestine into the lumen of the distal or proximal segment. It is one of the commonest causes of intestinal obstruction in the toddlers. Ileo-colic intussusception is the most common type. At times the inussusceptum may protrude through the anal canal and mimic a rectal prolapse. The diagnosis may be delayed in such cases leading to increase morbidity as well as mortality. Therefore, a high index of suspicion is required in such cases. In this case where a colo-colic intussusception presented like rectal prolapse. Emergency surgical reduction was carried out under general anaesthesia and the baby had a smooth recovery.

TERRITORIAL IMPACT ON CLINICAL OUTCOMES IN YOUNG POPULATION WITH ST-SEGMENT ELEVATION MYOCARDIAL INFARCTION

Objective: ST-segment elevation myocardial infarction (STEMI) at younger age though infrequent but very crucial entity, but there is dearth of available data, however, a rising trend has noticed recently in Asian countries. The aim was to see the territorial and clinical profile influence on overall outcomes of young individuals (≤35 years) with STEMI. Methodology: Patients with STEMI having age of ≤35 years during August 2020 to December 2020 were recruited and divided into left anterior descending artery (LAD)-culprit and non-LAD-culprit STEMI groups in this prospective observational study. Territorial angiographic and clinical characteristics were compared. Results: 1435 STEMI patients underwent coronary angiogram, 5.3% (94) were ≤35 years of age. LAD was culprit in 74.4% of STEMI mainly as a single vessel disease (SVD) involving the proximal segment as major territorial angiographic finding while 25.5% were non-LAD-culprit STEMI. Obesity, smoking, smokeless tobacco use especially gutka, were frequent in LAD-culprit group. In-hospital and at 3 months mortality was 2.1% (2) and 7.1% (5) respectively, all related to LAD territory. Rate of safe discharges and back to routine was 97.2% vs.100% and 70% vs.79.1% (72), respectively were comparable in both groups. Conclusion: LAD predominantly its proximal segment is the commonest culprit territory in patients with STEMI in youth with significant association to obesity, smoking and smokeless tobacco use especially gutka. LAD-culprit STEMI is the major territorial determinant for mortality and heart failure, however, overall clinical outcomes were reasonably good and comparable with non-LAD-culprit STEMI considering alive discharges and back to routine life.