Focal Stenosis Research Articles

Effects of stenotic lesion morphology on trans-lesional computed tomography derived fractional flow reserve (FFRCT) changes

Abstract Background To assess the indication for revascularization CT-derived fractional flow reserve (FFRCT) has been measured at only a portion distal to the lesion. This conventional method is controversial in terms of its ability to accurately evaluate the coronary flow disturbance. Changes in FFRCT between the portions proximal and distal to the lesion (ΔFFRCT) are implemented as a novel method for the assessment of the coronary flow disturbance. The effect of different morphologies of stenotic lesions on ΔFFRCT remains unclear. Purpose To investigate the effect of lesion morphology on ΔFFRCT and the ability of ΔFFRCT to detect lesions with the coronary flow disturbance. Methods A total of 1502 outpatients with suspected stable coronary artery disease who underwent FFRCT between January 2017 and May 2022 were evaluated. Among them, 76 patients who underwent both FFRCT and invasive coronary angiography with ≥ 50% stenosis were evaluated and divided into four groups according to the degree of stenosis and lesion length (moderate, 50–69%; severe: 70–99%) and lesion length (focal, < 40 mm; diffuse, ≥ 40 mm) as follows: moderate/focal (n = 23), moderate/diffuse (n = 9), severe/focal (n = 34), and severe/diffuse (n = 10) (Figure 1). Vessel and lesion morphology (length, luminal volume, and plaque characteristics) and left ventricular mass were assessed. Indication for revascularization (percutaneous coronary intervention and coronary artery bypass graft) was assessed by invasive coronary angiography and additional invasive FFR measurement was performed when necessary. Results ΔFFRCT was greater in diffuse than in focal stenosis in both moderate and severe stenosis: moderate/focal (0.11 ± 0.12), moderate/diffuse (0.18 ± 0.10), severe/focal (0.26 ± 0.15), and severe/diffuse (0.38 ± 0.12) (Figure 2A). Lesion length correlated with ΔFFRCT (r = 0.31, p = 0.006) (Figure 2B). As for focal lesion, lesion length did not correlate with ΔFFRCT (r = 0.13, p = 0.34), whereas, as for diffuse lesion it did (r = 0.72, p = 0.0007) (Figure 2C). Multivariable analysis showed that lesion length was the strongest predictor of ΔFFRCT (β-coefficient = 0.41, p = 0.003), followed by lesion positive remodelling (β-coefficient = 0.27, p = 0.01), lesion calcified plaque volume (β-coefficient = －0.39, p = 0.02), and lesion spotty calcification (β-coefficient = 0.23, p = 0.04). ΔFFRCT predicted for lesion requiring revascularization (cut-off 0.21, AUC 0.80, sensitivity 64.4%, specificity 85.7%, 95% CI 0.69–0.91) (Figure 2D). Conclusions ΔFFRCT was affected by lesion length, followed by lesion calcium components. ΔFFRCT predicted lesions requiring revascularization.Figure 1Figure 2

Abstract 11776: Sex Differences in Coronary Artery Disease Characteristics Among Patients With Type 2 Myocardial Infarction: Results From the Prospective DEFINE-Type 2 MI Study

Background: Type 2 Myocardial Infarction (T2MI) is a result of coronary supply and demand imbalance and is associated with a poor prognosis. It is crucial to identify potential sex-based differences in the prevalence and nature of coronary artery disease (CAD) within this specific population. Retrospective analyses are limited by selection bias, unequal proportions of male and female subjects, and lack of angiographic definition. Hypothesis: In patients with T2MI, women and men will have unique characteristics. Aim: To evaluate sex-based differences in presentation, prevalence/characteristics of CAD and clinical management of T2MI. Methods: In a single-center prospective study, patients with strictly adjudicated T2MI underwent coronary computed tomography angiography and Fractional Flow Reserve (FFR CT ) and quantitative plaque assessment was performed. Results: Of 50 study participants enrolled, 50% were women. Women with T2MI were older than men with T2MI (72.2 ± 10.1 vs. 64 ± 11.3 years; p = 0.009) but otherwise had similar baseline characteristics. A broad and similar mix of T2MI precipitants were present among both sexes. Ischemic ST depression was more common in women (64% vs. 32%; p = 0.05) while men were more likely to have T wave inversion (68% vs. 36%; p = 0.05). Women and men had comparable CAC scores (median [Q1, Q3] 152 [45, 762] vs. 234 [56, 422]; p = 0.07). Prevalence of any CAD (100% vs. 84%; p = 0.12), obstructive CAD (28% vs. 24%; p = 1.0), and hemodynamically significant focal stenosis with FFR CT < 0.80 (64% vs. 56%; p = 0.08) were similar between men and women. While total plaque volumes were similar between men and women, women had significantly lower levels of low-attenuation plaque (median [Q1, Q3]: 3 [1,7] vs. 9 [3, 14]; p = 0.03). Men and women did not significantly differ in percentile of plaque burden. Both sexes showed comparable increases in the utilization of aspirin (OR = 0.67; p = 0.53), beta blockers (OR = 0.76; p = 0.71), and statins (OR = 0.22; p = 0.08) by discharge. Conclusions: This prospective study of using FFRCT in T2MI identifies similarities and differences in clinical presentation and CAD characteristics of T2MI in both men and women. These findings may be helpful in improving the identification and management of T2MI.

Assessment of the effect of adrenaline toxicity, <i>Senna occidentalis L</i> and propranolol in the hearts of Wistar rats

The biological response that occurs when animals are exposed to stress affects their well-being. In this study, the methanolic extract of S. occidentalis was assessed for its ameliorative action against Adrenaline (Adr) toxicity in experimental myocardial stress induced by the administration of Adr in rats. Rats were treated with adrenaline, 2mg/kg of body weight intraperitoneally at an interval of 24 hours for 5days. Adr produced microscopic changes such as Cardiac Hypertrophy, Congestion, Fatty change, Focal Dystrophic Calcification in the stressed group. Other changes observed includes; Interstitial Fibrosis, Fatty infiltration, Focal vascular calcific stenosis, Focal interstitial lymphocytic infiltrate and Focal vascular calcific stenosis. Treatment with S. occidentalis and Propranolol reduced the complications in the heart. The result was thus concluded that the complications from the heart injury may have resulted in toxicity affecting normal histology of cardiac muscle.

Abstract 099: Reversible Cerebral Vasoconstriction Syndrome Secondary to Weight Loss Patch: A Case Report​

Introduction Reversible Cerebral Vasoconstriction Syndrome (RCVS) is a clinico‐radiographical syndrome characterized by severe thunderclap headache and reversible multifocal arterial vasoconstriction1. RCVS can be spontaneous or related to a trigger such as vasoactive medication/supplements. There is no previous data on the association of weight loss patch formulation in the genesis of unexplained RCVS. Methods A woman in her 40s presented with five days of recurrent acute onset severe right frontal headaches after starting Thrive weight loss patch supplementation. Head CT showed right frontal lobe hemorrhage with bilateral SAHs (Figure1). Brain MRI redemonstrated hemorrhages, numerous scattered foci of restricted diffusion, and a large area of restricted diffusion in the left insular cortex (Figure 2). Cerebral angiogram showed diffuse multifocal narrowing with a ‘beads‐on‐a‐string’ appearance of the cerebral vasculature and no aneurysms (Figure 3). Thrive patch contains undisclosed amounts of sympathomimetics and vasoactive compounds. Given the history, clinical symptoms of recurrent thunderclap headaches, and angiographic findings, the diagnosis of RCVS was made. Brain MRA 3 months after discharge showed no areas of cerebrovascular focal stenosis (Figure 4). At 4 month follow up, she reported 90% improvement of her symptoms. Results We report a temporal relationship between RCVS in a woman in her 40s and usage of a Thrive weight loss patch, which contains green tea extract, L‐arginine, 5‐hydroxytryptophan (5‐HTP), and Yerba Mate. We believe this report represents the first case of RCVS triggered by a weight loss patch. Multiple compounds within the Thrive patch have vasoactive properties that may contribute to RCVS genesis. Epigallocatechin (component of green tea extract) and 5‐HTP are metabolic compounds with potent vasoactive properties. They are components of weight loss and SSRI/SNRI medications respectively. Numerous studies have documented a temporal relationship between their use and subsequent development of RCVS2,3. Resolution of RCVS is reported after their discontinuation. Only one other case in our literature review investigated a patch modality in a temporal relationship with RCVS. It reported development and resolution of RCVS six days after nicotine patch use and discontinuation4. While Thrive patch does not contain nicotine, this case provides a further avenue for exploration as to whether pharmacokinetics of a patch modality influences a patient’s presentation with RCVS, as all prior reports document oral ingestion of substances. Conclusion Clinicians should be aware of the role of weight loss patches in RCVS, and their use should be assessed in large RCVS cohorts to clarify the association described in this report.

Abstract 032: Ovine Models for Cerebral Venous Catheter Access: A Single Center Experience

Introduction Large animal models are utilized for preclinical neuroendovascular research, and aid in the characterization and de‐risking of novel therapeutic approaches. To date, only a single prior study has been published providing a detailed account of an ovine model (Corriedale sheep) for cerebral venous access. The generalizability of these experiments has not yet been validated externally. In an effort to replicate these findings and de‐risk a novel, non‐surgical trans‐dural venous sinus approach to the cerebrum, cerebral venous access was attempted in 3 sheep specimens using transcranial and endovascular approaches. We report our experience validating this large animal model for translational and preclinical research. Methods 3 animal experiments were performed at the UCLA TRIC laboratory between 02/2022 and 10/2022. The sheep were anesthesitized and handled under approval of the Animal Research Committee at UCLA (protocol ARC 2020‐19). The neck and groin areas were shaved and aseptically prepped. MRI Brain and MR Brain venogram imaging was performed on a 3T Siemens Magnetom MRI. Femoral artery and external jugular vein access were obtained using the Seldinger technique under ultrasound guidance and did not require a surgical cut down. Two Suffolk and one Rambouillet sheep were used (average weight 60 kg and 40 kg, respectively). The animals were transferred to the catheter laboratory and image guidance was performed with a monoplane Siemens Artis Zeego. A transcranial approach to the dorsal sagittal sinus was attempted in one Suffolk sheep specimen utilizing a Hubly Drill and a micro‐puncture kit. An endovascular approach to the dorsal sagittal sinus was attempted in second Suffolk sheep specimen using a 25 cm, 8 Fr Pinnacle Sheath via the external jugular vein followed by a 132 cm Catalyst 5 catheter, 0.027" Medtronic Marksman, Stryker SL‐10 and Offset microcatheters assembled over 0.014" Synchro Standard and exchange‐length Choice PT microguidewires. In a third experiment, an endovascular approach to the dorsal sagittal sinus was attempted in a Rambouillet sheep specimen using a 95 cm TracStar, 115 cm Catalyst 5 catheter, and 0.027" Medtronic Marksman microcatheter assembled over 0.014" Synchro Standard and exchange‐length Boston Scientific (BS) Choice PT microguidewires. The 0.027" Marksman microcatheter was subsequently exchanged for a 2.7 French BS Stingray LP coronary CTO re‐entry microcatheter in the Rambouillet sheep, which was tracked to the anterior third of the dorsal sagittal sinus over the exchange length wire. Results A transcranial approach to the dorsal sagittal sinus was complicated by misaligned needle trajectories resulting in brain parenchymal damage. The external jugular vein was the conduit for accessing the first and second emissary veins of the retroauricular foramen (figure 2). Access to the temporal and then transverse sinuses was possible from either of the aforementioned emissary veins. Interestingly, the morphology of the dorsal sagittal sinus was bifid and each vessel channel measured between 1.65 – 1.7 mm in diameter (figure 1). Access to the temporal sinus from an endovascular approach was possible with all microcatheters. However, access with a 0.027" microcatheter beyond the torcular herophili and into the dorsal sagittal sinus was only possible in the Rambouillet sheep despite its smaller body size. Intermediate catheters (>4 Fr) could not be advanced beyond the skull base in none of the sheep breeds. Lastly, microcatheter advancement into the cerebral hemispheric space across a transdural venous sinus puncture access point deliberately created by wire perforation was feasible from the Stingray re‐entry system after exchanging for a 0.017" microcatheter. A coil (Stryker Target) was deployed extravascularly from the 0.017" microcatheter for post‐mortem characterization (figure 3). Conclusion One of three experiments met criteria for success. Due to reliance on a monoplane projection, a transcranial approach failed as an access route to the dorsal sagittal sinus resulting in iatrogenic parenchymal damage. Despite the larger body size, the second Suffolk sheep dural venous sinus system could not be catheterized beyond the skull base, likely due to the small caliber or focal stenosis of the temporal or transverse sinuses. The Rambouillet sheep breed proved to be a more adequate specimen for cerebral venous—specifically dorsal sagittal sinus—access with larger bore microcatheters. Based on this experience, careful selection of an appropriate sheep breed is necessary for modeling endovascular cerebral venous access and assessing novel procedures.

Abstract 056: Patterns of Care in the Management of Intracranial Atherosclerosis‐related Large Vessel Occlusion–the RESCUE‐LVO survey

Introduction Intracranial atherosclerosis‐related large vessel occlusion (ICAS‐LVO) is a common cause of failed mechanical thrombectomy (MT) in acute ischemic stroke (AIS) [1]. Treatment of ICAS‐LVO with rescue stenting and/or angioplasty has shown promising outcomes, but diagnosing ICAS‐LVO during MT can be challenging [2, 3]. There are uncertainties regarding optimal approaches, techniques, and timing for treating ICAS‐LVO. To understand current practice patterns and address these uncertainties, we conducted a survey among neurointerventional practitioners experienced in ICAS‐LVO management during MT. Methods We conducted an international online survey of neurointerventionalist members of the Society of Neurointerventional Surgery (SNIS) and the Society of Vascular and Interventional Neurology (SVIN). The 28‐question poll evaluated the preferences on diagnosis, treatment, and endovascular approach to ICAS‐LVO. Results 168 individual survey responses were obtained from practicing neurointerventional physicians. Overall, 40.6% reported an incidence of 6–10% of ICAS‐LVO during MT. Most neurointerventionalists (91%) diagnose ICAS‐LVO after a continued or recurrent occlusion or by the presence of fixed focal stenosis (FFS) after multiple MT attempts. Most respondents (86%) preferred acute treatment of ICAS‐LVO with rescue stenting (RS) +/‐ angioplasty. However, in patients who achieved recanalization with a severe FFS, the majority (44%) recommended maximal medical management only. The preferred medication during acute RS was intravenous antiplatelet therapy (69%), and after acute RS was dual oral antiplatelet therapy (58%). Fear of hemorrhagic complications (70%) was the most compelling reason not to perform RS +/‐ angioplasty. Twenty‐five percent of respondents were hesitant to randomize patients to acute RS versus medical therapy in a future randomized trial because of the lack of sensitive and specific biomarkers to diagnose ICAS‐LVO before MT treatment. Conclusion Our survey highlights the significant variability and uncertainty in the diagnosis and management of ICAS‐LVO during MT among neurointerventional practitioners. There is no equipoise regarding the optimal treatment strategy, and the fear of hemorrhagic complications associated with antithrombotic medications contributes to the variation in practice. Our survey underscores the need for future research and randomized clinical trials to address the uncertainties in the management of ICAS‐LVO during MT. Improved imaging biomarkers and consensus guidelines are essential to guide clinical decision‐making and optimize patient outcomes in this challenging population of AIS patients.

Effect of F11 Receptor/Junctional Adhesion Molecule-A–derived Peptide on Neointimal Hyperplasia in a Murine Model

PurposeTo determine whether inhibition of the F11 receptor/JAM-A (F11R) using F11R-specific antagonist peptide 4D results in inhibition of smooth muscle cell (SMC) proliferation and migration in vivo, known as neointimal hyperplasia (NIH), using a mouse focal carotid artery stenosis model (FCASM). Materials and MethodsThe mouse FCASM was chosen to test the hypothesis because the dominant cell type at the site of stenosis is SMC, similar to that in vascular access stenosis. Fourteen C57BL/6 mice underwent left carotid artery (LCA) partial ligation to induce stenosis, followed by daily injection of peptide 4D in 7 mice and saline in the remaining 7 mice, and these mice were observed for 21 days and then euthanized. Bilateral carotid arteries were excised for histologic analysis of the intima and media areas. ResultsThe mean intimal area was significantly larger in control mice compared with peptide 4D–treated mice (0.031 mm2 [SD ± 0.024] vs 0.0082 mm2 [SD ± 0.0103]; P = .011). The mean intima-to-intima + media area ratio was significantly larger in control mice compared with peptide 4D–treated mice (0.27 [SD ± 0.13] vs 0.089 [SD ± 0.081]; P = .0079). NIH was not observed in the right carotid arteries in both groups. ConclusionsPeptide 4D, an F11R antagonist, significantly inhibited NIH in C57BL/6 mice in a FCASM.

Integrated myocardial flow reserve (iMFR) assessment: optimized PET blood flow quantification for diagnosis of coronary artery disease.

Distinguishing obstructive epicardial coronary artery disease (CAD) from microvascular dysfunction and diffuse atherosclerosis would be of immense benefit clinically. However, quantitative measures of absolute myocardial blood flow (MBF) integrate the effects of focal epicardial stenosis, diffuse atherosclerosis, and microvascular dysfunction. In this study, MFR and relative perfusion quantification were combined to create integrated MFR (iMFR) which was evaluated using data from a large clinical registry and an international multi-center trial and validated against invasive coronary angiography (ICA). This study included 1,044 clinical patients referred for 82Rb rest/stress positron emission tomography myocardial perfusion imaging and ICA, along with 231 patients from the Flurpiridaz 301 trial (clinicaltrials.gov NCT01347710). MFR and relative perfusion quantification were combined to create an iMFR map. The incremental value of iMFR was evaluated for diagnosis of obstructive stenosis, adjusted for patient demographics and pre-test probability of CAD. Models for high-risk anatomy (left main or three-vessel disease) were also constructed. iMFR parameters of focally impaired perfusion resulted in best fitting diagnostic models. Receiver-operating characteristic analysis showed a slight improvement compared to standard quantitative perfusion approaches (AUC 0.824 vs. 0.809). Focally impaired perfusion was also associated with high-risk CAD anatomy (OR 1.40 for extent, and OR 2.40 for decreasing mean MFR). Diffusely impaired perfusion was associated with lower likelihood of obstructive CAD, and, in the absence of transient ischemic dilation (TID), with lower likelihood of high-risk CAD anatomy. Focally impaired perfusion extent derived from iMFR assessment is a powerful incremental predictor of obstructive CAD while diffusely impaired perfusion extent can help rule out obstructive and high-risk CAD in the absence of TID.

SAT474 A Case Report Of Moyamoya Disease Associated With Uncontrolled Graves' Disease

Abstract Disclosure: Z. Tan: None. E. Briggie: None. M. Correia: None. Background: Moyamoya disease is an uncommon cerebrovascular disease that is featured by narrowing of large intracranial arteries and the development of prominent small-vessel collaterals. The etiology of Moyamoya disease is unknown, but it can be associated with multiple conditions including atherosclerosis, sickle cell disease, and Protein S deficiency. It is rarely associated with uncontrolled Graves’ disease. Clinical Case: A 37-year-old female with a history of Graves’ disease and type 1 diabetes presented with sudden onset of slurred speech and right-sided weakness. A CTA of the head and neck showed a small hypodensity in the left basal ganglia without corresponding perfusion deficit and narrowed left internal carotid arteries without focal stenosis. In addition, a brain MRI showed patchy infarcts in the left middle cerebral artery territory. A cervical and cerebral angiogram showed multiple areas of stenosis which was concerning for Moyamoya disease. She ultimately underwent balloon angioplasty of the left internal carotid artery with improvement in perfusion. During the workup for secondary causes of Moyamoya disease, her TSH was < 0.01 µIU/mL (0.270-4.20 µIU/mL), with elevated T4 at 3.84 ng/dl (0.80-1.80 ng/dl) and elevated TSI at 15.5 IU/L (< 0.54 IU/L). Importantly, she was diagnosed with Graves’ disease 2 years before admission, and this condition has never been well controlled due to poor compliance with methimazole. A TSH measured 5 months before admission was also undetectable with elevated T4 at 2.8 ng/dl. Her other workups for Moyamoya disease were negative including HIV antigen/antibody, syphilis IgG antibody, Lyme disease IgG & IgM antibodies, hepatitis panel antibodies, ANA, ANCA, free protein S, dsDNA antibody, factor 5 Leiden mutation, vascular endothelial growth factor-D and urine drug screening test. She started methimazole 20 mg daily and was discharged to acute rehabilitation. After rehabilitation, her Graves’ disease is slowly improving with most recent TSH < 0.008 µIU/mL and free T4 at 2.39 ng/dl. She is almost back to her baseline with significant improvement in speech and strength. Conclusion: Uncontrolled Graves’ disease should be considered in the differential diagnosis of Moyamoya disease in young subjects who present with stroke-like symptoms. Reference: Ischemic Stroke and Intraventricular Hemorrhage in Moyamoya Syndrome Associated With Graves' Disease: A Case Report. Neurologist 2022 Presentation Date: Saturday, June 17, 2023

Segmental low-density area on contrast-enhanced CT is a possible clue to diagnosing branch artery fibromuscular dysplasia.

Fibromuscular dysplasia can cause renovascular hypertension. Since fibromuscular dysplasia may be underdiagnosed, precise diagnosis and management are crucial, especially for young women. A 20-year-old woman with hypertension and hypokalemia was referred to our hospital for further evaluation of secondary hypertension. At the previous hospital, her blood pressure was 160/110 mmHg and the serum potassium level was 2.9 mEq/L. The equilibrium phase on contrast-enhanced computed tomography revealed a low-density area in the upper median portion of the right kidney. On admission to our hospital, her blood pressure was 141/96 mmHg under 5 mg of amlodipine. Laboratory tests revealed plasma renin activity of 11.3 ng/mL/h and plasma aldosterone concentration of 117.1 pg/mL. Renal venous sampling of active renin concentration showed a right-to-left renin ratio of 3.13, confirming a significant increase in renin secretion from the right kidney. Selective reno-angiography detected focal stenosis with adjacent aneurysmal dilation and tortuosity in the proximal branch of the right renal artery. She was diagnosed with branch artery fibromuscular dysplasia and successfully treated with percutaneous transluminal angioplasty. After the treatment, she was free from hypertension and hypokalemia without any medications. Since branch artery fibromuscular dysplasia is sometimes difficult to diagnose, contrast-enhanced computed tomography can be a promising diagnostic tool as shown in this case. Concerning treatment, our patient was treated with percutaneous transluminal angioplasty, which should be considered for women of reproductive age because recommended antihypertensive medications can be teratogenic even in the first trimester of pregnancy. Although branch artery fibromuscular dysplasia (FMD) is sometimes difficult to diagnose, it should be considered in patients with high-renin, high-aldosterone hypertension. Branch artery FMD can present with a low-density area of the kidney on contrast-enhanced computed tomography, as shown in this case. Percutaneous transluminal angioplasty (PTA) can be an appropriate treatment for branch artery FMD, especially in young female patients. PTA may immediately improve hypertension and hypokalemia without the need for medications.

Coronary Computed Tomographic Angiography With Fractional Flow Reserve in Patients With Type 2 Myocardial Infarction

BackgroundType 2 myocardial infarction (T2MI) related to a supply/demand imbalance of coronary blood flow is common and associated with poor prognosis. Coronary artery disease (CAD) may predispose some individuals to T2MI and contribute to its high rate of recurrent cardiovascular events. Little is known about the presence and extent of CAD in this population. ObjectivesThe goal of this study was to evaluate the presence and characteristics of CAD among patients with T2MI. MethodsIn this prospective study, consecutive eligible individuals with Fourth Universal Definition of Myocardial Infarction criteria for T2MI were enrolled. Participants underwent coronary computed tomography angiography (CTA), fractional flow reserve derived with coronary CTA (FFRCT), and plaque volume analyses. ResultsAmong 50 participants, 25 (50%) were female, and the mean age was 68.0 ± 11.4 years. Atherosclerotic risk factors were common. Coronary CTA revealed coronary plaque in 46 participants (92%). A moderate or greater stenosis (≥50%) was identified in 42% of participants, and obstructive disease (≥50% left main stenosis or ≥70% stenosis in any other epicardial coronary artery) was present in 26%. Prevalence of obstructive CAD did not differ according to T2MI cause (P = 0.54). A hemodynamically significant focal stenosis identified by FFRCT was present in 13 participants (26%). Among participants with a stenosis ≥50% (n = 21), FFRCT excluded lesion-specific hemodynamically significant stenosis in 8 cases (38%). ConclusionsAmong individuals with adjudicated T2MI, CAD was prevalent, but the majority of patients had nonobstructive CAD. Mediators of ischemia are likely multifactorial in this population. (Defining the Prevalence and Characteristics of Coronary Artery Disease Among Patients with Type 2 Myocardial Infarction using CT-FFR [DEFINE TYPE 2 MI]; NCT04864119)

Temporal changes in PET myocardial perfusion imaging over 15 years: patient characteristics and imaging findings

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): DF. Sager was supported by the Swiss Academy of Medical Sciences and the G.&J. Bangerter-Rhyner Foundation through the “Young Talents in Clinical Research” program. Background & Purpose Positron emission tomography (PET)/computed tomography (CT) myocardial perfusion imaging (MPI) is guiding the assessment and management of patients with suspected or known coronary artery disease for over 30 years. Its clinical dissemination and technological evolution might have altered the clinical phenotype of referred patients. The aim of the present study was to investigate temporal trends in patient characteristics, imaging findings of PET/CT MPI and outcome over the course of 15 years. Methods In this cross-sectional cohort study, 1366 patients who underwent PET/CT between 2001 and 2015 were retrospectively included. Patients were grouped together into three 5-year study groups (group 1: 2001–2005 / group 2: 2006–2010 / group 3: 2011–2015) and assessed for patient demographics and characteristics, serological biomarkers, relative and quantitative PET findings, and mortality. Vital status was obtained from medical charts and/or death notices. Results Across study groups, mean age (p<0.001) and creatinine (p = 0.006) increased while the prevalence of typical angina (p<0.001) and known coronary artery disease (p = 0.003) decreased (Table). There were no temporal changes in neither the prevalence of dyspnea (p = 0.480) and diabetes mellitus (p = 0.146) nor median body mass index (p = 0.064), NT-proBNP (p = 0.532) and troponin (p = 0.385). Although the prevalence of ischemia (p = 0.019) and scar (p = 0.003) decreased over time, median myocardial flow reserve (MFR) worsened (p = 0.001). Over a median follow-up of 5.3 years [interquartile range 3.3–7.4] annualized mortality increased across groups in parallel to the changes in MFR (Figure). Conclusion The clinical phenotype of patients referred for PET/CT MPI has changed marginally between 2001 and 2015. The temporal trend towards older, less symptomatic patients with lower prevalence of ischemia and scar but worse MFR and higher mortality highlights the importance of assessing diffuse atherosclerosis and microcirculation beyond focal stenosis to improve risk stratification.

Cardiac Computed Tomographic Angiography Evaluation of Right Ventricle-Pulmonary Artery Conduits with Surgical Correlation.

Right ventricle-pulmonary artery (RV-PA) conduits are used in the treatment of certain congenital heart disease (CHD). RV-PA conduit complications might develop over time and require intervention. To evaluate how well cardiac computed tomographic angiography (CCTA) performs compared to transthoracic echocardiography (TTE) in evaluating RV-PA conduit complications by using surgical findings as the reference standard. A retrospective chart review of all patients over a 5-year period who underwent CCTA for RV-PA conduit evaluation was performed. Patient demographics and clinical data were recorded. Preoperative CCTA and TTE findings were compared to the operative findings for concordance or discordance. Forty-one patients were included, 51% females. The complications were conduit stenosis (28.68%), infection (7.17%) and aneurysm/pseudoaneurysm (6.15%). TTE and CCTA were consistently able to visualize focal conduit stenosis (96%). The greatest discrepancy between TTE and CCTA was in evaluating for aneurysm/pseudoaneurysm, where TTE detected only 2/6 (33%) compared to CCTA which detected 6/6 (100%) of the cases. However, TTE was slightly better at detecting conduit infection (3/7, 43%) compared to CCTA (2/7, 29%). Note that 5 out of 7 patients with endocarditis had bovine jugular graft. CCTA and TTE provide similar diagnostic accuracy evaluating certain types of RV-PA conduit complications. However, certain complications were only visualized on CCTA or TTE making both modalities complementary to each other during diagnostic evaluation.

External Validation of Atherosclerotic Neuroimaging Biomarkers in Emergent Large‐Vessel Occlusion

Background Intracranial atherosclerosis related large vessel occlusion (ICAS‐LVO) is the major cause of failed mechanical thrombectomy. ICAS‐LVO causes reocclusion or a fixed focal stenosis, leading to suboptimal revascularization and poor functional outcomes. We aimed to externally validate 4 preidentified imaging biomarkers of ICAS‐LVO: absent hyperdense sign, Hounsfield units (Hu ratio ≤1.1 and Delta Hu <6) and truncal‐type occlusion, observed on admission noncontrast computed tomography and computed tomography angiography in patients presenting with emergent large‐vessel occlusion (ELVO). Methods We conducted a retrospective cohort observational study of consecutive patients presenting with acute M1/terminal internal carotid artery occlusions undergoing mechanical thrombectomy. Inability to locate a hyperdense vessel on noncontrast computed tomography at the corresponding ELVO on computed tomography angiography was labeled absent hyperdense sign. Delta Hu and Hu ratio were defined as the difference and ratio of the Hu of the ELVO on noncontrast computed tomography and its mirror contralateral patent vessel, respectively. ELVO was classified as truncal‐type occlusion if the bifurcation distal to the occlusion was spared on computed tomography angiography. ICAS‐LVO was defined as the presence of fixed focal stenosis or reocclusion after mechanical thrombectomy. Statistical analysis was performed using C statistics, receiver operating characteristic curve analysis, and multivariate logistic regression. Results Of 161 patients, 30 (18.6%) had suspected ICAS‐LVO. Absent hyperdense sign had a sensitivity of 90% and specificity of 87% (area under the curve [AUC], 0.88), in predicting ICAS‐LVO. Hu ratio ≤1.1 (AUC, 0.89) and Delta Hu <6 (AUC, 0.96) had sensitivity of 100% and 97% and specificity of 79% and 95%, respectively. Truncal‐type occlusion showed a sensitivity of 75% and specificity of 98% (AUC, 0.87). When comparing receiver operating characteristic AUC, Delta Hu <6 was significantly better than absent hyperdense sign ( P =0.006); Hu ratio ≤1.1 ( P =0.006); and truncal‐type occlusion ( P =0.02). Conclusion Combination of neuroimaging biomarkers using noncontrast computed tomography and computed tomography angiography in ELVO identify ICAS‐LVO with high predictive power. Larger, prospective, multicenter studies are warranted to further evaluate their effectiveness in diagnosing ICAS‐LVO.

AORTIC INVOLVEMENT IN FIBROMUSCULAR DYSPLASIA: REPORT FROM ARCADIA-POL

Objective: Fibromuscular dysplasia (FMD) affects the walls of medium-sized arteries. There are no described radiological characteristics pathognomonic of aortic FMD but pathological documentation of aortic FMD has been occasionally reported. The aims of this study were to investigate the characteristics of abdominal aorta in patients with FMD versus controls and to review the relevant literature. Design and method: We measured centreline abdominal aortic diameters on 136 patients with FMD (22 with focal disease) enrolled in the ARCADIA-POL study, 60 patients with carotid dissections but no evidence of FMD and 136 healthy controls. Results: The median abdominal aortic diameter did not differ between patients with FMD, patients with carotid dissections and no evidence of FMD and healthy controls. However, aortic diameter at the level of the diaphragm was smaller in patients with focal FMD compared to patients with multifocal FMD, patients with carotid dissections and healthy controls (ANOVA 0.015). Six patients with mid-aortic syndrome (MAS) were reported separately. All had radiological evidence of FMD in medium-sized aortic branches. In one in whom a sample of aortic wall was obtained, histology confirmed focal aortic FMD. A literature review found a further 31 reports of aortic histology with features of FMD. Conclusions: We found no difference in aortic diameters between individuals with or without FMD. Nevertheless, patients with focal FMD had smaller aortic diameters than those with multifocal FMD and controls. This represents another phenotypic difference between multifocal and focal FMD. Focal renal artery stenosis associated with MAS may represent an extreme presentation belonging to the same disease spectrum.

One-dimensional modeling of microvascular hemodynamics in the retina using multimodal imaging

Modeling techniques are an essential complement to clinical studies of the retina, as they provide access to non-measurable parameters throughout the network and enable the simulation of controlled disturbances or pathologies. In this work, we propose the development of a patient-specific one-dimensional model of the arterial circulation in the retina. Our model is based on conservation laws and utilizes morphometric and velocimetric data obtained through clinical multimodal imaging to construct the network topology and impose realistic boundary conditions. Specifically, our model simulates blood flow from the central retina artery to the terminal smallest arterioles. To validate our model, we perform a sensitivity analysis and compare its results to published data. Finally, we use our model to investigate the hemodynamic consequences of focal stenosis on retinal arteries. Overall, our model provides a valuable tool for exploring the complex dynamics of retinal blood flow and their potential clinical implications.

Ketamine Induced RCVS (P3-12.008)

<h3>Objective:</h3> To present a case of RCVS induced by ketamine infusions compounded with triptan and NSAID usage. <h3>Background:</h3> A 47 yo female with a history of depression and migraines presented with a persistent headache for 3 days. On the day of presentation, the patient reported the “worst headache of her life”. The headache was “sharp and squeezing”, frontal and retro-orbital in location, radiating to the back of her head, and exasperated by laying flat. The patient reported taking multiple high-dose NSAIDs along with sumatriptan. She had completed a 3-week course of ketamine infusions (75 mg twice weekly for depression) with last infusion 2 days prior to presentation. She was also on a chronic SSRI for depression. Patient denied any alcohol or current recreational drug use, but did report a history of opioid dependency. Initial CT head demonstrated a moderate-sized right frontal lobe subarachnoid and a small subarachnoid in the right posterior parietal lobe. CTA of head and neck demonstrated vasospasm of the left supraclinoid ICA, left M1 segment, and basilar artery. The location, radiographic appearance, and temporal course was consistent with RCVS. CT Angiogram was negative for any luminal irregularity, focal stenosis, or narrowing. MRI brain with contrast redemonstrated the subarachnoid hemorrhage without evidence of a vasculitic process. Lab work-up was negative for ANA, C4, C3, Sjogren’s Antibodies, RF, Anti-DNAs Ab. CRP and ESR were mildly elevated suggesting mild inflammation. <h3>Design/Methods:</h3> N/A <h3>Results:</h3> The etiology of the headache and subarachnoid hemorrhage was suspected to be medication induced RCVS in the setting of concomitant use of sumatriptan, SSRI, and high doses of ketamine. <h3>Conclusions:</h3> Although a rare phenomena, RCVS is a concerning cause of thunderclap headache that should be recognized. RCVS is not a common occurrence with ketamine usage but clinicians should be aware is this possible adverse effect. <b>Disclosure:</b> Dr. Mufti has nothing to disclose. Dr. Canlas has nothing to disclose. Dr. Ritenuti has nothing to disclose.

Renal infarction caused by fibromuscular dysplasia

Introduction: Fibromuscular dysplasia (FMD) is an atherosclerotic/non-inflammatory disease, usually involving the renal and internal carotid arteries. Renal infarction is a rare condition that can present with flank pain and can be caused by FMD. Case Report: A 49-year-old female patient was admitted to the emergency department with complaints of flank pain, fever, nausea, vomiting, and chills. Her blood pressure was normal. Abdominal examination showed right costovertebral tenderness. Laboratory assessment showed hematuria, leukocytosis, increased C-reactive protein (CRP), and increased lactate dehydrogenase (LDH). Nephrolithiasis was strongly considered a cause of pain because of the nature of the pain and the presence of hematuria. The urinary system ultrasound was normal. On the computed tomography (CT), in contrastenhanced sections, an infarct area was detected in the lower pole of the right kidney. In renal angiography, severe focal stenosis was seen in the polar renal artery, and angioplasty was made. Conclusion: Renal infarction can be caused by FMD and may be misdiagnosed as renal colic.

Computational Fluid Dynamics in Intracranial Atherosclerotic Disease

Recurrent stroke risk in intracranial atherosclerotic disease remains high despite aggressive medical therapy. While hemodynamic insufficiency appears to be a strong marker of stroke recurrence, natural history studies using various unimodal imaging modalities have shown mixed results, as they likely do not adequately capture the complex local hemodynamic environment generated by a focal stenosis. Computational fluid dynamics, a multimodal tool used to simulate fluid flow and the interactions between fluids and surfaces, has recently been used to illustrate the complex hemodynamic environment surrounding intracranial atherosclerotic lesions and to risk‐stratify patients on the basis of simulated outputs. We aimed to summarize the literature pertaining to computational fluid dynamics use in intracranial atherosclerotic disease and to describe its future potential use in generating more targeted therapies.

Biodegradable polymeric nanoparticles increase risk of cardiovascular diseases by inducing endothelium dysfunction and inflammation

Biodegradable polymers are expected to be an alternative to plastics. Because of its high biocompatibility, poly (lactic-co-glycolic acid) (PLGA) is widely used in medicine. It has been reported that micro-nano plastics can be accumulated in the circulatory system and cause tissue injury. With the increasing environmental exposure of degradable polymer nanoparticles (NPs), the impact of this risk factor on cardiovascular disease deserves attention. Thus, we aim to study the harmful effect of PLGA NPs on the process of vascular stenosis which is a typical pathological feature of cardiovascular diseases. We establish a mouse vascular stenosis model with intravenously injecting of PLGA NPs for 2 weeks. This model leads to a significant narrowing of the left common carotid artery which is characterized by the increasing intima area and focal stenosis. We observe that PLGA NPs accelerate stenosis progression by inducing inflammation and impairing vascular function. It promotes the proliferation of smooth muscle cells and causes abnormal collagen distribution. The combination of wall shear stress and PLGA NPs uptake speed up endothelial cell damage, decrease endothelial permeability and cell migration capacity. Our results suggest that PLGA NPs may pose a risk in cardiovascular stenosis which inspire us to concern the biodegradable polymeric materials in our living especially the clinic applications.Graphical