High-intensity Transient Signals Research Articles

Prevalence of Neurovascular Microemboli After Transcatheter Aortic Valve Replacement

BackgroundNeurolotic sequelae after transcatheter aortic valve replacement (TAVR) can cause significant morbidity and mortality. Transcranial Doppler (TCD) imaging can show real-time high intensity transient signals (HITS), which reflect active microembolization. Although it is well known that intraprocedural microembolism occurs, it is not known if this embolic phenomenon continues in the postprocedural period. We investigated whether microemboli occur post-TAVR and whether we could determine any clinical, procedural, or echocardiographic predictors. MethodsWe evaluated HITS in 51 consecutive patients undergoing unprotected TAVR with low-, intermediate-, or high-risk Society of Thoracic Surgeons score. Patients were excluded if they did not have temporal windows for insonation of the middle cerebral artery or if they were not willing to participate. Primary outcomes of HITS 24 hours post-TAVR were observed using a Philips iU22 TCD. TCD was performed at 3 time points (pre-, peri-, and post-TAVR) for each patient, before, during, and 24 hours postprocedure. ResultsWhile no HITS were detected in any of the patients preoperatively, all patients had HITS during the procedure. Interestingly, 56.8% had HITS 24 hours post-TAVR. One patient with HITS post-TAVR had a stroke 48 hours after TAVR. ConclusionWe observed a high prevalence of microemboli 24 hours post-TAVR. None of the predictors for intraprocedural microembolism seemed to play an important role for post-TAVR microemboli.

Cerebral emboli detection and autonomous neuromonitoring using robotic transcranial Doppler with artificial intelligence for transcatheter aortic valve replacement with and without embolic protection devices: a pilot study

BackgroundPeriprocedural ischemic stroke remains a serious complication in patients undergoing transcatheter aortic valve replacement (TAVR). We used a novel robotic transcranial Doppler (TCD) system equipped with artificial intelligence (AI) for...

Embolic Stroke Following Intravenous Ozone Therapy (P2-5.007)

<h3>Objective:</h3> NA <h3>Background:</h3> Ozone therapy via autohemotherapy has become among the alternative therapies purported to treat chronic lymphocytic leukemia. Ozone gas is injected into blood drawn from the patient, which is mixed then transfused back intravenously. Due to the infrequent use of this modality, it has not been previously reported as a risk factor for stroke. <h3>Design/Methods:</h3> A 62-year-old man with a history of chronic lymphocytic leukemia, chronic migraines, hypertension, and diabetes mellitus type II presented with acute left arm numbness followed by weakness during administration of intravenous (IV) ozone. Shortly after, he developed a migrainous headache, which is typical for him. Neurological examination revealed left upper and lower extremity weakness. CT head and CT angiography were performed and were unremarkable. The patient was treated with IV tPA. He continued to have left-sided weakness and numbness along with a migrainous headache after the intervention. MRI of the brain revealed multiple bilateral frontal and parietal infarcts. Dual antiplatelet therapy was initiated. Echocardiogram revealed a large patent foramen ovale (PFO) with a right-to-left shunt. A transcranial doppler with bubble study revealed multiple high intensity transient signals post valsalva maneuvers, supporting the diagnosis of paradoxical emboli. Patient eventually underwent successful outpatient PFO closure without complications. <h3>Results:</h3> NA <h3>Conclusions:</h3> This case presents a rare cause of stroke following IV injection of ozone. Acute stroke following ozone therapy has not been previously reported in the literature. The pathogenesis remains unknown, although it is theorized that it may have been due to IV administration of ozone-mixed blood in the presence of a PFO. It is imperative to recognize this phenomenon as a potential risk of embolic stroke in patients receiving IV ozone treatment. <b>Disclosure:</b> Dr. Kokash has nothing to disclose. Dr. Zahra has nothing to disclose. Dr. Singh has nothing to disclose. Dr. Yacoub has nothing to disclose. Dr. Leary has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Boston Clinical Research Institute. Dr. Leary has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Baim Clinical Research Institute. Dr. Leary has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Syneos Health. Dr. Leary has received publishing royalties from a publication relating to health care.

A Scoping Review of Cerebral Doppler Arterial Waveforms in Infants.

Cerebral Doppler ultrasound has been an important tool in pediatric diagnostics and prognostics for decades. Although the Doppler spectrum can provide detailed information on cerebral perfusion, the measured spectrum is often reduced to simple numerical parameters. To help pediatric clinicians recognize the visual characteristics of disease-associated Doppler spectra and identify possible areas for future research, a scoping review of primary studies on cerebral Doppler arterial waveforms in infants was performed. A systematic search in three online bibliographic databases yielded 4898 unique records. Among these, 179 studies included cerebral Doppler spectra for at least five infants below 1 y of age. The studies describe variations in the cerebral waveforms related to physiological changes (43%), pathology (62%) and medical interventions (40%). Characteristics were typically reported as resistance index (64%), peak systolic velocity (43%) or end-diastolic velocity (39%). Most studies focused on the anterior (59%) and middle (42%) cerebral arteries. Our review highlights the need for a more standardized terminology to describe cerebral velocity waveforms and for precise definitions of Doppler parameters. We provide a list of reporting variables that may facilitate unambiguous reports. Future studies may gain from combining multiple Doppler parameters to use more of the information encoded in the Doppler spectrum, investigating the full spectrum itself and using the possibilities for long-term monitoring with Doppler ultrasound.

Detection of Cerebral High-Intensity Transient Signals by NeoDoppler during Cardiac Catheterization and Cardiac Surgery in Infants.

There is a risk of gaseous and solid micro-embolus formation during transcatheter cardiac interventions and surgery in children with congenital heart disease (CHD). Our aim was to study the burden of high-intensity transient signals (HITS) during these procedures in infants. We used a novel color M-mode Doppler (CMD) technique by NeoDoppler, a non-invasive ultrasound system based on plane wave transmissions for transfontanellar continuous monitoring of cerebral blood flow in infants. The system displays CMD with 24 sample volumes and a Doppler spectrogram. Infants with CHD undergoing transcatheter interventions (n=15) and surgery (n=13) were included. HITS were manually detected based on an "embolic signature" in the CMD with corresponding intensity increase in the Doppler spectrogram. Embolus-to-blood ratio (EBR) defined HITS size. A total of 1169 HITS with a median EBR of 9.74 dB (interquartile range [IQR]: 5.10-15.80 dB) were detected. The median number of HITS in the surgery group was 45 (IQR: 11-150), while in the transcatheter group the median number was 12 (IQR: 7-24). During cardiac surgery, the highest number of HITS per hour was seen from initiation of cardiopulmonary bypass to aortic X-clamp. In this study we detected frequent HITS and determined the feasibility of using NeoDoppler monitoring for HITS detection.

Transcranial Doppler for stratification of high-risk morphology of patent foramen ovale in patients with cryptogenic stroke.

Microbubble testing using transcranial Doppler (TCD) is an important screening tool for diagnosing paradoxical cerebral embolism with high-risk PFO. However, little is known about the association between the microbubble test by TCD and the features of high-risk PFO evaluated by transesophageal echocardiography (TEE). We studied 101 consecutive patients at Showa University, from April 2019 to October 2020, who underwent both TCD and TEE with a sufficient Valsalva maneuver and who were strongly suspected by neurologists as cryptogenic stroke. According to the appearance of microbubbles as high-intensity transient signals (HITS), the TCD grade was stratified into three categories based on the criteria (A: none, no HITS, B: small; 1-10 HITS, and C: large; > 10 HITS, or an uncountable number of HITS). Among patients with RLS through the PFO in TEE, high-risk morphological features of PFO for cerebral embolism were evaluated as follows: (1) tunnel height, (2) tunnel length, (3) total excursion distance of the atrial septum into the right and left atrium, (4) existence of Eustachian valve or Chiari network, (5) angle of PFO from the inferior vena cava, and (6) large shunt (20 or more microbubbles). Of 101 patients (TCD grade; Group A = 49, Group B = 26, Group C = 26), RLS through PFO was detected in 37 patients (grade A = 8, grade B = 6, grade C = 23) by TEE. Among PFO-positive patients, tunnel height, length, total excursion distance into the right and left atria, angle of PFO from the inferior vena cava, and frequency of large shunt in TEE were significantly larger in grade C than in grade A and B (p < 0.05). Additionally, grade C patients had significantly more forms of high-risk PFOs than those in grades A and B when the six features of high-risk PFO were compared. A multivariate logistic regression demonstrated that the tunnel length of PFO and the presence of large shunt in TEE were independently associated with large HITS in TCD (odds ratio: 1.18 and 49.5, 95% confidence interval 1.043-1.337 and 10.05-244.3, p = 0.0086 and p < 0.0001, respectively). In conclusion, the existence of a large HITS detected by TCD may have a screening advantage in predicting the high-risk morphologies of PFO that can cause paradoxical cerebral embolism.

Abstract 117: Contrast-enhanced Transcranial Doppler Ultrasonography Versus Transesophageal Echocardiography As Screening Tool In Embolic Stroke

Introduction: Right-to-left (RtL) intracardiac and intrapulmonary shunts are associated with embolic stroke. Although contrast-enhanced transcranial doppler ultrasonography (ceTCD) and transesophageal echocardiography (TEE) are used in embolic stroke work up, there are no standardized guidelines as to which test should be considered as ‘gold standard’. Our objective is to evaluate the sensitivity of contrast-enhanced TCD and TEE in detecting right-to-left shunt to determine respective utilities as screening tools. Methods: Electronic medical records of subjects presenting with acute neurological symptoms who had ceTCD and TEE were evaluated. Sensitivity and specificity were calculated. Based on the respective prevalence of intracardiac and intrapulmonary shunts, positive predictive value, negative predictive value, and test accuracy were determined for ceTCD and TEE. Social Science Statistics was used for data analysis. Results: From June 2016 to August 2021, of 7,498 ischemic stroke patients, 260 patients were suspected of having strokes related to right to left shunts and underwent ceTCD and TEE for detection of cardioembolic sources for stroke. A positive right-to-left shunt was detected in 83 subjects. Detection by ceTCD was confirmed by the operator for 81 patients while 2 were considered false positive results (delayed sporadic High Intensity Transient Signals (HITS)). Sensitivity of ceTCD was 97.65% (95% CI [91.76%, 99.71%]). No safety concerns were identified in patients undergoing ceTCD. Of those with positive ceTCD (68.57%, n=35) were detected by Valsalva, and all of those 35 patients had negative TEE. TEE had sensitivity of 70.34% (95% CI [61.23%, 78.39%]). Conclusion: Contrast-enhanced TCD has superior sensitivity, is cost-effective, practical, and a safe alternative to TEE in identifying intracardiac or intrapulmonary shunts. Screening superiority of ceTCD may lie in ability to elicit shunts during Valsalva maneuvers. To our knowledge this is the largest single center series confirming ceTCD as a gold standard tool for screening of right to left shunts.

Abstract 1122‐000153: Larger Functional Shunts are Associated with Greater Cerebrovascular Disease Burden

Introduction : The relationship between embolic stroke and patent foramen ovale (PFO) is well‐established. Our objective was to evaluate the association between high intensity transient signals (HITS) in contrast‐enhanced transcranial doppler ultrasonography (ceTCD), baseline MRI brain small vessel ischemic changes, and rates of acute ischemic stroke in the setting of focal neurological deficits. Methods : Electronic medical records of subjects with acute onset neurological symptoms who had ceTCD and MRI brain were evaluated. Subjects without a reported Spencer grade and/or MRI brain without available DWI and FLAIR sequences were excluded. Acute stroke rates and baseline Fazekas score in low‐grade (Spencer grade 1–2) and high‐grade (Spender grade 3–5) shunts were analyzed using Z score for 2 population proportions and Mann‐Whitney U test, respectively. Social Science Statistics was used for data analysis. Results : From June 2016 to August 2021, of 7,498 consecutive ischemic stroke patients, 132 patients were identified as possible strokes related to PFO and were hospitalized with focal neurological deficit, underwent ceTCD and MRI brain. Acute stroke was confirmed on DWI in 60% of Spencer grade 1 (n = 73), 72.2% of grade 2 (n = 19), 72.7% of grade 3 (n = 29), and 80% of grades 4 and 5 shunts (n = 11). Acute stroke rates between low grade (grades 1–2) and high grade shunts (grades 3–5), did not reach statistical significance (z = ‐0.9181; p = 0.17879). There was no significant difference in periventricular white matter disease (z = 0.85697; p = 0.19489). Fazekas scores assessing deep white matter disease were statistically significant between low‐ and high‐grade shunts (z = 1.92818; p = 0.0268 Conclusions : A trend towards statistical significance was observed in high‐grade shunt association with higher rate of acute stroke. Deep white matter disease burden may be significantly higher in high‐grade shunts. Further prospective studies are needed to corroborate our findings.

Abstract 1122‐000180: Contrast‐Enhanced Transcranial Doppler Ultrasonography Versus Transesophageal Echocardiography as Screening Tool in Embolic Stroke

Introduction : Right‐to‐left (RtL) intracardiac and intrapulmonary shunts are associated with embolic stroke. Although contrast‐enhanced transcranial doppler ultrasonography (ceTCD) and transesophageal echocardiography (TEE) are used in embolic stroke work up, there are no standardized guidelines as to which test should be considered as ‘gold standard’. Our objective is to evaluate the sensitivity of contrast‐enhanced TCD and TEE in detecting right‐to‐left shunt to determine respective utilities as screening tools. Methods : Electronic medical records of subjects presenting with acute neurological symptoms who had ceTCD and TEE were evaluated. Sensitivity and specificity were calculated. Based on the respective prevalence of intracardiac and intrapulmonary shunts, positive predictive value, negative predictive value, and test accuracy were determined for ceTCD and TEE. Social Science Statistics was used for data analysis. Results : From June 2016 to August 2021, of 7,498 ischemic stroke patients, 260 patients were suspected of having strokes related to right to left shunts and underwent ceTCD and TEE for detection of cardioembolic sources for stroke. A positive right‐to‐left shunt was detected in 83 subjects. Detection by ceTCD was confirmed by the operator for 81 patients while 2 were considered false positive results (delayed sporadic High Intensity Transient Signals (HITS)). Sensitivity of ceTCD was 97.65% (95% CI [91.76%, 99.71%]). No safety concerns were identified in patients undergoing ceTCD. Of those with positive ceTCD (68.57%, n = 35) were detected by Valsalva, and all of those 35 patients had negative TEE. TEE had sensitivity of 70.34% (95% CI [61.23%, 78.39%]). Conclusions : Contrast‐enhanced TCD has superior sensitivity, is cost‐effective, practical, and a safe alternative to TEE in identifying intracardiac or intrapulmonary shunts. Screening superiority of ceTCD may lie in ability to elicit shunts during Valsalva maneuvers. To our knowledge this is the largest single center series confirming ceTCD as a gold standard tool for screening of right to left shunts.

Effectiveness of atrial fibrillation on high-intensity transient signals to cerebral circulation during TAVI

Abstract Background Cerebral microemboliazations remain a major concern peri-operatively and following Transcatheter Aortic Valve Implantation (TAVI). We evaluated whether atrial fibrillation may predispose to an increased number of cerebrovascular emboli during the procedure. Purpose The aim of the study was to evaluate, using a transcranial doppler, the effect of atrial fibrillation on transient high-intensity signals to middle cerebral arteries during transcatheter aortic valve implantation. Methods Consecutive patients who underwent transfemoral TAVI with Evolut™ R bioprosthesis, were categorized into two groups. Group A patients with permanent atrial fibrillation (AF) on anticoagulation, Group B patients with sinus rhythm (SR). Dual antiplatelet therapy with aspirin and clopidogrel was administered to all patients 24 hours prior to the procedure at loading dose, with patients in Group A receiving in addition low-molecular-weight-heparin. The number of detected High Intensity Transient Signals (HITS) was assessed using Rimed Digi-Lite™ Transcranial Doppler on both cerebral arteries during the following phases of the procedure; Phase 0: 30 minutes prior to procedure initiation, Phase I: between access site puncture and introduction of the delivery system, Phase II: during the implantation of the bioprosthesis, until the removal of the delivery system. All implantations were performed without predilation. Furthermore, patients were evaluated by neurologist before TAVI and on discharge day. Safety was evaluated according to VARC-2 criteria. Results Twenty-eight patients were evaluated (81±6 years, 16 males (57.1%)). Group A had higher number of total (786±95 vs. 604±103, p=0.002) as well as Phase I HITS (393±94 vs. 285±86, p=0.002). One cerebrovascular event was recorded in Group A and one patient categorized to Group B developed major bleeding due to conversion to femoral surgical cut-down. The average number of received blood units, was higher in AF compared to SR Group (Group 1: 0.8±1.9 vs. Group 2: 0.5±0.7, p: 0.886), without however, reaching statistical significance. Conclusion Patients with atrial fibrillation had larger burden of embolic HITS during TAVI indicating high risk patients for embolic cerebrovascular events. This may has implications for future strategies for cerebral embolic protection. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): Ippokrateio General Hospital of Athens

Analysis of encephalic lesions on magnetic resonance imaging in patients with Transcranial Doppler high intensity transient signals

Objective: To describe magnetic resonance imaging (MRI) findings of the brain in patients younger than 65 years who were studied by transcranial Doppler (TCD) with microbubble contrast, with a history of cryptogenic cerebrovascular accident (CVA) and suspected patent foramen ovale (PFO).Materials and methods: This retrospective cross-sectional study included patients of both sexes, younger than 65 years of age.Results: Our sample (n = 47.47% male and 53% female, mean age is 42 years) presented high-intensity transient signals (HITS) positive in 61.7% and HITS-negative in 38.3%. In HITS-positive patients, lesions at the level of the subcortical U-brains, single or multiple with bilaterally symmetrical distribution, predominated. In patients with moderate HITS, lesions in the vascular territory of the posterior circulation predominated.Conclusion: In patients younger than 65 years with cryptogenic stroke and subcortical, single or multiple U-shaped lesions with bilateral and symmetrical distribution, a PFO should be considered as a possible cause of these lesions.

Comparison of Ticagrelor Versus Clopidogrel on Cerebrovascular Microembolic Events and Platelet Inhibition during Transcatheter Aortic Valve Implantation

The impact of the antiplatelet regimen and the extent of associated platelet inhibition on cerebrovascular microembolic events during transcatheter aortic valve implantation (TAVI) are unknown. Our aim was to evaluate the effects of ticagrelor versus clopidogrel and of platelet inhibition on the number of cerebrovascular microembolic events in patients undergoing TAVI. Patients scheduled for TAVI were randomized previous to the procedure to either aspirin and ticagrelor or to aspirin and clopidogrel. Platelet inhibition was expressed in P2Y12 reaction units (PRU) and percentage of inhibition. High intensity transient signals (HITS) were assessed with transcranial Doppler (TCD). Safety outcomes were recorded according to the VARC-2 definitions. Among 90 patients randomized, 6 had an inadequate TCD signal. The total number of procedural HITS was lower in the ticagrelor group (416.5 [324.8, 484.2]) (42 patients) than in the clopidogrel group (723.5 [471.5, 875.0]) (42 patients), p <0.001. After adjusting for the duration of the procedure, diabetes, extra-cardiac arteriopathy, BMI, hypertension, aortic valve calcium content, procedural ACT, and pre-implantation balloon valvuloplasty, patients on ticagrelor had on average 256.8 (95% CI: [-335.7, -176.5]) fewer total procedural HITS than patients on clopidogrel. Platelet inhibition was greater with ticagrelor 26 [10, 74.5] PRU than with clopidogrel 207.5 (120 to 236.2) PRU, p <0.001, and correlated significantly with procedural HITS (r=0.5, p <0.05). In conclusion, ticagrelor resulted in fewer procedural HITS, compared with clopidogrel, in patients undergoing TAVI, while achieving greater platelet inhibition.

Monitoring of cerebral high intensity transient signals during catheter interventions and surgery for congenital heart disease in infants using NeoDoppler

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The Joint Research Committee between St. Olavs Hospital and the faculty of Medicine, NTNU. The Norwegian Association for Children with Congenital Heart Disease Research Foundation, FFHB Background   There is a risk of gaseous- and solid micro embolus formation during transcatheter procedures (CATH) and surgery in children with congenital heart disease (CHD). Silent strokes during surgery or CATH may contribute to neurological impairment. NeoDoppler is a non-invasive ultrasound system based on plane wave transmissions to continuously monitor cerebral blood flow in infants with an open fontanelle. Gaseous- and solid micro embolus passing through the ultrasound beam create High Intensity Transient Signals (HITS) in the Doppler signal.  Purpose We aimed to study the amount of HITS during CATH and surgery in infants using NeoDoppler.  Methods   The NeoDoppler probe operates at a frequency of 7.8 MHz. The frame rate is 300 fps and the beam covers a wide cylindrical area (10/35mm width/depth). The system displays a color M-mode Doppler and a spectrogram. The broad ultrasound beam permits prolonged scanning time of each event as the HITS move through the ultrasound beam. The high framerate and color M-mode allows for tracking of embolies in depth. In this study the NeoDoppler probe was attached to the anterior fontanelle of infants with CHD during CATH (n = 15) and cardiac surgery (n = 13). HITS were defined as high intensity signal creating skewed lines in the color M-mode Doppler moving away or towards the probe (blue/red) with a corresponding high intensity signal in the spectrogram. HITS were grouped into single HITS and HITS with curtain effect. Single HITS were defined as single skewed lines in the color M-mode Doppler and spectrogram. HITS with curtain effect were defined as skewed broad lines or multiple intensity increase lines in the color M-mode Doppler with corresponding intensity increase that filled the entire doppler curve. HITS with curtain effect are believed to represent numerous HITS that could not be separated from each other in the spectrogram. HITS were manually detected in an in-house MatLab application. Results   The study group consisted of 28 infants (17 males) with different CHD who underwent CATH or surgery. The median age and weight was 96 days (range 3-240 days) and 5650 g (range 2400-8085 g). HITS were detected in 13/15 patients during CATH with a total of 392 HITS (Median 12, Range 0-149) and in all patients during surgery with a total of 772 HITS (Median 45, Range 11-150).  The picture shows examples of single HITS (panel A) and HITS with curtain effect (panel B). One can appreciate the embolic trajectory pattern in depth over time in the color M-mode Display.  Conclusion   In this study we found that NeoDoppler enables detection of frequent HITS in patients with CHD undergoing surgery or CATH. NeoDoppler could become a useful tool to guide modifications of procedures, with aim to reduce the risk of silent stroke. However, further studies are needed to validate the technique. Abstract Figure.

Screening results using high intensity transient signals for carotid artery in general companies

Screening results using high intensity transient signals for carotid artery in general companies

Correlation of platelet inhibition and cerebral thromboembolic events, as expressed with number of high-intensity transient signals,during Transcatheter Aortic valve Implantation

Abstract Background It has been shown that high Residual Platelet Reactivity (RPR) may contribute to platelet aggregation which propagates thrombosis on implanted materials. Therefore, we evaluated whether high RPR may predispose to an increased number of cerebrovascular emboli during Transcatheter Aortic valve Implantation (TAVI). Methods Consecutive patients who underwent transfemoral TAVI with a self-expandable valve were prospectively studied. A loading dose of P2Y12 inhibitor 24 hours preprocedurally was given. Additionally, aspirin was started one week prior to procedure in all patients. Platelet inhibition was assessed with P2Y12 reaction units (PRU) (Verify Now assay) as well as percentage of inhibition 30 minutes prior to procedure initiation. The number of High intensity transient signals (HITS) was assessed with Rimed Digi-Lite™ transcranial Doppler, setting a threshold for detection of HITS at 3dB, continuously, on both middle cerebral arteries during the whole procedure. Two observers reviewed offline the number of HITS. Results In total, 84 patients underwent TAVI (53 males, mean age=81.9yrs old ±8,98). Mean baseline PRU and percentage of platelet inhibition was 258,24±43,03 (156–376) and 48,51%±40.05 (0–100%) respectively. In the treated patients the mean absolute total number of HITS and the number of HITS per minute recorded, was 566,63±272,32, (136–1432) and 6.7/min±3.3 (2.09–13.24) respectively. Significant positive correlation was found between baseline PRU levels and number of total HITS (r=0.261, p=0.017), (Figure 1). Multivariate regression analysis revealed that PRU was independent prognostic factor of total HITS (β=0.708, p=0.06), In order to clarify the predictive role of platelet inhibition in the total number of recorded HITS a ROC analysis was performed, obtaining an area under the curve of 0.646 (95% CI 0.518 to 0.773, p=0.047). PRU-levels≥169 were shown to predict number of HITS at the upper quartile with 76% sensitivity and 65% specificity. Conclusion High RPR after dual antiplatelet loading with a P2Y12 inhibitor and aspirin, resulted in larger burden of embolic HITS during TAVI procedure. A cut off point of 169 PRU units with 76% sensitivity and 65% specificity predicted detection of HITS at the higher quartile. PRU-HITS Correlation Funding Acknowledgement Type of funding source: None

High-intensity transient signals during transcatheter aortic valve implantation assessed by ultrasonic carotid artery blood-flow monitoring: A single center prospective observational study

BackgroundNo reports to date have assessed the procedural patterns of high-intensity transient signals (HITS) by monitoring blood flow in cervical arteries. The aim of this study was to examine the sequential distribution of HITS in each procedural phase and predictive factors for HITS during transcatheter aortic valve implantation (TAVI) by monitoring blood flow in the common carotid artery. MethodsThis prospective observational study included 73 patients who underwent TAVI via the transfemoral artery approach. We continuously evaluated and analyzed HITS from administration of heparin to valve implantation. ResultsHITS peaked during balloon valvuloplasty (BAV), amounting to almost 30% of the total HITS count, followed by valve implantation [BAV 141 (73–186) and valve implantation 86 (64–126), respectively]. In univariate and multivariate analysis, the Agatston score of the aortic valve and low-density lipoprotein were confirmed as independent predictors of HITS frequency with logarithmically converted coefficients of 0.00015 (p < 0.001) and 0.0032 (p = 0.027), respectively. ConclusionsThese results provide the first evidence that micro-emboli deriving from calcified burden were scattered primally during BAV, followed by valve implantation. The Agatston score may be a predictor for the amount of HITS.

Most High-Intensity Transient Signals Are Not Associated With Specific Surgical Maneuvers.

Mortality after congenital heart defect surgery has dropped dramatically in the last few decades. Current research on long-term outcomes has focused on preventing secondary neurological sequelae, for which embolic burden is suspected. In children, little is known of the correlation between specific surgical maneuvers and embolic burden. Transcranial Doppler ultrasound is highly useful for detecting emboli but has not been widely used with infants and children. Bilateral middle cerebral artery blood flow was continuously monitored from sternal incision to chest closure in 20 infants undergoing congenital heart defect repair or palliative surgery. Embolus counts for specific maneuvers were recorded using widely accepted criteria for identifying emboli via high-intensity transient signals (HITS). An average of only 13% of all HITS detected during an operation were correlated with any of the surgical maneuvers of interest. The highest mean number of HITS associated with a specific maneuver occurred during cross-clamp removal. Cross-clamp placement also had elevated HITS counts that significantly differed from other maneuvers. In this study of infants undergoing cardiac surgery with cardiopulmonary bypass, the great majority of HITS detected are not definitively associated with a specific subset of surgical maneuvers. Among the measured maneuvers, removal of the aortic cross-clamp was associated with the greatest occurrence of HITS. Future recommended research efforts include identifying and confirming other sources for emboli and longitudinal outcome studies to determine if limiting embolic burden affects long-term neurological outcomes.

Transcranial Doppler Emboli Monitoring for Infective Endocarditis.

Ischemic stroke can occur in 20-55% of patients with infective endocarditis (IE) with 75% occurring during the first 2 weeks of treatment. CT or MRI brain can diagnose the sequelae of stroke but transcranial Doppler (TCD) can document active embolization. We undertook a retrospective review of our patient cohort and a systematic review of literature to assess the role of TCD in early diagnosis and management of ischemic stroke in IE. Retrospective chart review and literature review. We found 89 patients with stroke caused by IE at our institution from December 2011 to April 2018. TCDs were obtained on 26 patients; 16 were abnormal for cerebrovascular abnormalities. Only 4 patients had 30-minute emboli monitoring performed, of which one revealed emboli. We found 3 studies investigating the role of TCDs in IE that showed promise in its use as a predictive tool in stroke risk stratification. Presence of embolization in the form of high-intensity transient signals (HITS) detected on TCDs can be used for early diagnosis of IE, assessing efficacy of antibiotic therapy, and stratification of stroke risk in IE. This can aid further research into testing preventative interventions for reducing stroke burden in IE such as earlier valvular surgery or vacuum-assisted vegetation extraction.

Assessing Cerebrovascular Hemodynamics Using Transcranial Doppler in Patients with Mechanical Circulatory Support Devices.

Mechanical circulatory support (MCS) devices are commonly used in heart failure patients. These devices carry risk for presumably embolic and additionally hemorrhagic stroke. Alterations in blood flow play a key role in stroke pathophysiology, and we aimed to learn more about hemodynamic compromise. In this study, we used transcranial Doppler (TCD) ultrasound to define hemodynamics of commonly used nonpulsatile MCS devices, as well as pulsatile devices, with special attention to the total artificial heart (TAH). From 2/2013 through 12/2016, we prospectively enrolled patients with MCS who underwent TCD imaging. We analyzed TCD parameters, including peak systolic velocity, end-diastolic velocity, pulsatility indices (PIs), and number of high-intensity transient signals. Waveform morphologies were compared between various MCS devices. We performed 132 TCD studies in 86 MCS patients. Waveforms in patients supported by venoarterial-extracorporeal membrane oxygenation demonstrated continuous flow without clear systolic peaks with an average (±SD) PI of .43 (±.2). PIs were low in patients with continuous-flow left ventricular assist devices with a mean PI of .32 (±.13). Impella patients had morphologically distinct pulsatile waveforms and a higher mean PI of .65 (±.24). In intra-arterial balloon pump patients, mean PI was 1.01 (±.16) and diastolic upstrokes were pronounced. In TAH patients, mean middle cerebral artery velocity of 79.69 (±32.33) cm/seconds and PI of .74 (±.14) approached normal values. TCD can detect characteristic waveforms in patients supported by various MCS devices. These device-specific TCD patterns are recognizable and reproducible.

Basilar artery thrombosis during sexual intercourse

An ischemic stroke during sexual intercourse is very rare. A basilar artery thrombosis during sexual intercourse has not been described previously. We report a young woman with a life-threatening basilar artery thrombosis during sexual intercourse, with a resulting locked-in syndrome. The positive high intensity transient signals (HITS) diagnosis showed a right-to-left shunt and is in line with paradoxic embolism. The molecular genetics revealed a homozygosity 4G/4G in the region PAI1, -675 (promoter polymorphism) as a risk factor for ischemic stroke. Sexual intercourse is a possible, albeit unusual stroke cause, especially in young people.