Impact of pulmonary veins anatomy on outcome of cryoablation or radiofrequency catheter ablation for atrial fibrillation

Funding Acknowledgements

Type of funding sources: None.

BACKGROUND

Pulmonary vein isolation is the cornerstone of interventional treatment of atrial fibrillation (AF). Pulmonary veins frequently display anatomic variants. If this influences the recurrence of AF after catheter ablation is still a matter of debate.

PURPOSE

Our aim was to determine if pulmonary vein anatomy variants influences the recurrence of AF after catheter ablation with radiofrequency or cryoablation.

METHODS

Retrospective analysis of patients with paroxysmal or persistent atrial fibrillation who underwent pulmonary vein isolation by radiofrequency (RF) or cryoablation (CA) in a single center between January 2017 and September 2019. All patients underwent computed tomography before AF ablation. Within each treatment group (RF or CA), patients were stratified according to their PV anatomy in: regular (2 left PVs and 2 right PVs) or variant (left common trunk, right common trunk, bilateral common trunk, right intermediate branch or other). The primary end-point was 1-year recurrence of AF. Recurrence was defined as electrical documented AF.

RESULTS

A total of 425 patients (RF = 300 and CA = 125), aged 56.6 ± 11.7 years, 277 men (65.0%) were enrolled. The majority of patients had paroxysmal AF (n = 343, 81.5%). Mean CHA2DS2-VASc score was 1.12 ± 1.28. Regular PV anatomy was identified in 357 patients (84.0%), a left common trunk in 53 patients (12.5%), a bilateral common trunk in 5 patients (1.2%), a right intermediate branch in 3 patients (0.7%) and other mixed variants in 7 patients (1.6%). There were no significant differences in the baseline clinical and echocardiographic characteristics between groups.

At 1-year follow-up, patients with atypical PV anatomy had more AF recurrence (regular 8.1% vs variant 16.2%; p = 0.037). Analyzing according to the ablation technique there was no difference in AF recurrence between PV anatomy groups in patients submitted to radiofrequency (regular 8.3% vs variant 13.0%; p = 0.224). On the other hand, in cryoablation group, patients with PV anatomic variant had significantly higher rates of 1-year AF recurrence (regular 7.8% vs variant 22.8%; p= 0.033).

CONCLUSION

The presence of atypical PVs anatomy seems to be associated with higher rates of AF recurrence at 1-year in patients undergoing cryoablation. Further prospective studies are needed to confirm the PV anatomy impact in the success of the procedure and if this needs to be accounted in the choice of ablation technique. Abstract Figure. Recurrence in AF after cryoablation

Comparing single approaches success in index atrial fibrillation ablation

Funding Acknowledgements

Type of funding sources: None.

Introduction

Atrial Fibrillation (AF) ablation can be performed by inducing pulmonary vein electrical isolation. There are two widely used approaches: point-by-point and single-shot.  Catheter AF ablation is effective in restoring and maintaining sinus rhythm. However, efficacy is limited by high rate of AF recurrence, after an initially successful procedure.

Purpose

To evaluate AF index ablation successfulness using single-shot techniques and compare them to conventional one (point-by-point using irrigated- tip ablation catheter).

Methods

We analyzed, from a single center, all patients submitted to an index AF ablation procedure and its successfulness. The last was defined as AF, atrial tachycardia or flutter recurrence (with a duration superior to 30seconds) event- free survival, determined by holter and/or event recorder. These exams were performed after 6 and 12months and then annually, until 5years post procedure were accomplished.

Results

From November 2004 to November 2020, 821patients were submitted to first AF ablation (male patients 67,2%(N = 552), mean age of 59 ± 12years old). Paroxysmal AF(PAF) was present in 62,9%(N = 516), with short-duration persistent AF in 21,8%(N = 179) and long-standing persistent in 15,3%(N = 126). Ablation techniques were irrigated tip catheter point-by-point (PbP)ablation in 266 patients (32,4%) and single-shot (SS)techniques on the remaining 555(67,6%), including PVAC in 294(35,8%),225(27,4%) submitted to cryoablation and 36(4,4%) to nMARQ.

Globally, AF ablation had one-year success rate of 72,5%, and 56,2% at 3 years. A significant difference between AF duration type was found: Arrhythmic recurrence risk was 58% higher in persistent AF(PeAF) (HR 1.58;95%IC 1,22-2,04; p < 0.001). In patients presenting with PAF prior to the procedure, success was significantly higher in those submitted to SS technique(HR:0.69;95%CI 0,47-0,90;p = 0.046), while those with PeAF had similar results.

Conclusion

In this single center analysis almost three-quarters had achieved one-year event-free survival, and more than a half reached long-term freedom from atrial arrhythmia. Patients with paroxysmal atrial fibrillation submitted to single-shot procedure presented with a higher success-rate. Moreover, our study confirmed previous data on the importance of atrial fibrillation classification to postprocedural outcomes. Abstract Figure. Survival Curves

Compulsorily notifiable diseases and health problems and socio-environmental conditions: an ecological study, Espírito Santo, Brazil, 2011-2015

OBJECTIVE

To analyze association between climatic-environmental conditions and occurrence of compulsorily notifiable diseases and health problems, in the state of Espírito Santo, Brazil, 2011-2015.

METHODS

This was an ecological study of municipality clusters calculated based on cases confirmed on the Notifiable Health Conditions Information System for the period 2011-2015.

RESULTS

Notifications were more frequent among females (51.1%); people of brown race/skin color (31.7%); in the 20-49 year age group (48.1%) and in the Metropolitan Health Region (60.3%). The factors associated with health problems were ambulatory care sensitive conditions (p-value<0.001); education development index (p-value<0.001); temperature (p-value=0.019) and degree of urbanization (p-value=0.004). Diseases were associated with population density (p-value<0.001); temperature (p-value<0.001), humidity (p-value<0.001) and altitude (p-value=0.005).

CONCLUSION

Health problems were positively associated with ambulatory care sensitive conditions, the education development index and temperature; but negatively associated with degree of urbanization. Diseases were positively associated with the factors mentioned.

The use of an electronic form to register play observation of a child with anxiety: A study case at a university clinical practice in Brazil

Introduction

The modality of assessment used at a University Clinical Practice in Brazil is interventive psychodiagnosis in which the active participation of children and families is considered. Orientation is given following the input provided by children and their parents.

Objectives

Evaluating the use of an electronic form to be fulfilled during the observation of a child’s play in psychological session.

Methods

A child at the age of 5yrs 4m was brought for psychological assessment with the complaint of aggressiveness and irritability. His parents answered the Child Behavior Checklist (CBCL -1 1/12 5 yrs) and the Psychology interns had to observe the child’s play and fulfill an electronic form in which the choice of toys and plays, motricity, creativity, symbolic abilities, frustration tolerance, adequation with reality were verified.

Results

The results of CBCL indicated that the child was within the clinical range regarding anxiety and depression along with somatic complaints. The indicators observed in the electronic form such as rigidity in the modality of play, the lack of adequate ability of impersonating in role-playing, the difficulty of using creativity during play unless he was guided by peers or the Psychology interns and the constant anguish of separating himself from his parents were crucial for parents’ orientation. The psychological treatment lasted five months and benefited from the information obtained through the form once the symptoms of irritability and aggressiveness were reduced.

Conclusions

This modality of assessment can be instructional for parents and may also reduce financial and time costs once provides specific indicators to observe during play.

Voice Disorders Detection Through Multiband Cepstral Features of Sustained Vowel

This study aims to detect voice disorders related to vocal fold nodule, Reinke's edema and neurological pathologies through multiband cepstral features of the sustained vowel /a/. Detection is performed between pairs of study groups and multiband analysis is accomplished using the wavelet transform. For each pair of groups, a parameters selection is carried out. Time series of the selected parameters are used as input for four classifiers with leave-one-out cross validation. Classification accuracies of 100% are achieved for all pairs including the control group, surpassing the state-of-art methods based on cepstral features, while accuracies higher than 88.50% are obtained for the pathological pairs. The results indicated that the method may be adequate to assist in the diagnosis of the voice disorders addressed. The results must be updated in the future with a larger population to ensure generalization.

P1457Does high density mapping increase the efficacy of ischemic ventricular tachycardia ablation?

Introduction

 The treatment of ventricular tachycardia (VT) in patients (pts) with ischemic heart disease (IHD) represents a challenge because of its high morbidity and mortality rates and low long-term success rates. In the VANISH clinical trial, 51% of pts undergoing the conventional ablation technique developed within 2 years the combined outcome of mortality or electrical storm (ES) or appropriate CDI shock. The use of high-density substrate maps can lead to greater precision in substrate evaluation and ideally to improved ablation success.

Objectives

 To assess the efficacy of substrate-guided ischemic VT ablation using high-density mapping.

Methods

 Single-center prospective study of consecutive IHD pts submitted to endocardial ablation of substrate-guided VT using multipolar catheters (PentaRayTM or HDGridTM) and three-dimensional mapping systems with automatic annotation software. The maps were evaluated in order to identify the intra-cicatricial channels (areas of bipolar voltage &lt;1.5mV) in which sequential propagation of local abnormal ventricular activities (LAVAs) were observed, during or after QRS. The ablation strategy aimed at the abolition of all intra-cicatricial LAVAs, directing the radiofrequency applications primarily to the entrances of the channels. The success of ablation was assessed by the primary outcome (death by any cause or ES or appropriate CDI shock) at 2 years and compared to the population of the VANISH study undergoing conventional ablation, using Cox regression and Kaplan- Meier survival analysis.

Results

 We included 40 patients, 95% males, 70 ± 8 years, mean ejection fraction 34 ± 10%. 82% on previous amiodarone therapy and 72% were ICD carriers. 32% underwent ablation during hospitalization for ES and 20% had previously undergone VT ablation. The median duration of substrate mapping was 74 minutes, with a mean of 2290 collected points. Major complications were seen in 1 patient (aortic dissection). During a mean follow-up time of 17.3 ± 12.9 months, the long-term success rate of VT ablation was 75%. Additionally, there was a reduction in the proportion of patients receiving amiodarone before vs after ablation (82% vs. 45% respectively). The rate of events observed during follow-up was lower than expected, namely by comparison with the population of the VANISH study undergoing conventional ablation (25% vs 51% at 24 months, HR 0.42 CI 95% 0.2-0.88, p = 0.022), reflecting a relative risk reduction of 58%.

Conclusions

 High density mapping allows a detailed characterization of the dysrhythmic substrate in patients with VT in an IHD context. Our results suggest that these technological innovations may be improving the clinical success of VT ablation.

Abstract Figure.

P945What is the role of late-potentials determined by signal-averaged ECG in predicting flecainide provocative test in brugada pattern?

Introduction

The sudden cardiac death risk in Brugada Syndrome (BrS) is higher in patients with spontaneous type 1 pattern. Brugada diagnosis is also established in patients with induced type 1 morphology after provocative test with intravenous administration with a sodium blocker channel. Nevertheless, this group of patients is known to be at a lower risk of SCD, and their risk stratification is still a matter of discussion.  Late potentials (LP) detected on signal-averaged ECG (SAECG) on the RVOT have been previously proposed as a predictor factor for BrS, even though data is lacking on its value.

Purpose

To evaluate the association between positive LP (LMS40&gt; 38ms) on SAECG with modified Brugada leads and a positive flecainide test in patients with non-type 1 BrS.

Methods

Retrospective single-center study of non-type 1 BrS patients referred for the performance of a flecainide provocative test. Patients presenting with spontaneous type 1 morphology were excluded from the study. Study of LP on SAECG with modified leads for Brugada were evaluated before administration of flecainide [2mg/kg (maximum150mg), for 10minutes] with determination of filtered QRS duration (fQRS), root mean square voltage of the last 40ms of the QRS complex (RMS40) and duration of low amplitude signals &lt;40μV of the terminal QRS complex (LMS40).

Results

126 patients (47.3 ± 14.1 years, 61.9% males) underwent study with LP SAECG and flecainide test. Among these patients, 7.9% were symptomatic and 16.7% had familiar history of BrS. Flecainide test was positive in 46.8% of patients.

In patients with a positive flecainide test, 64.4% presented LMS40 &gt; 38ms whereas LMS40 &gt; 38ms was present in only 46% of those with a negative flecainide test (p = 0.031). The presence of positive LMS40 was a positive predictor for a positive flecainide test, associated with a two-fold increase likelihood in the induction of a Brugada pattern (OR: 2,12; IC95% 1,025-4,392; P = 0,043).

There was no association between fQRS or RMS40 and a positive flecainide test (p = NS). fQRS &gt; 114ms and RMS40 &lt;20uV was present in 22% and 61% of patients with a positive flecainide test, respectively.

Conclusion

In patient with non-type 1 Brugada syndrome, LMS40 &gt; 38ms in SAECG was a predictor for a positive flecainide test, suggesting that this finding could be helpful on the risk stratification of patients undergoing diagnostic study for Brugada syndrome.

Abstract Figure. Effect of LMS 40 in flecainide test

P1402Isolation of pulmonary veins with duty-cycled circular multi-polar catheter: randomized controlled clinical trial

Introduction

Pulmonary vein isolation (PVI) is the central element in the ablation of atrial fibrillation (AF), and can be obtained with different ablation modalities. The duty-cycled circular multi-pole catheter PVAC® (Medtronic) allows linear application of radiofrequency energy, with the production of circumferential lesions. Conceptually, it can make ablation simpler and faster in patients with favorable anatomy.

Objectives

To evaluate the safety and efficacy of ablation with a PVAC® catheter and to compare it with the conventional technique point-by-point (PbP) with irrigated catheter.

Methods

Clinical trial with single-blinded patients with AF refractory to antiarrhythmic therapy, randomized (1: 1) for ablation with PVAC® or PbP. The ablation strategy consisted of PVI, complemented with ablation of the cavo-tricuspid isthmus in patients with history of concomitant flutter. Monitoring was performed with a 7-day event loop recorder at 3, 6 and 12 months and annually from the 2nd year. Success was defined by AF-free survival or any maintained supraventricular tachycardia (duration &gt; 30seconds).

Results

354 patients (67.5% males, 58 ± 12 years, PbP: 175, PVAC: 179) were included, of which 59.1% had paroxysmal, 26.2% short-standing persistent and 14.7% had long-standing persistent AF. Baseline characteristics were similar between groups. Among patients treated with PVAC, 93.1% of the pulmonary veins were isolated (620/666), similar to the 98.3% immediate success of the PbP group (697/709). Although the complication rate was similar in both groups (PVAC: 4.9% vs. PbP: 7.8%; P = NS), the risk of hemopericardium was lower with PVAC (0% vs. 4.6%; P = 0.013). Two patients treated with PVAC developed stroke (1.13% vs. 0%; P = NS). The duration of the procedure was lower among the patients treated with PVAC [136 (100-180) vs. 230 (188-270) min; P &lt;0.001], with no difference in fluoroscopy time [24.4 (14.5-36.8) vs. 27.1 (17.0-45.0) min]. The success rate after 1st ablation at 36 months was 68%, with no differences between groups. The success rate after multiple ablations increased to 85.8%, with no differences between groups.

Conclusion

The multipolar PVAC catheter can represent an added value in AF ablation, making the procedure simpler and faster, ensuring similar efficacy to the conventional technique and with a lower risk of cardiac tamponade. The present trial suggests the need for clinically manifested stroke risk surveillance, which may be increased with this technique.

Abstract Figure.

Prasugrel Versus Ticagrelor in Patients With CYP2C19 Loss-of-Function Genotypes: Results of a Randomized Pharmacodynamic Study in a Feasibility Investigation of Rapid Genetic Testing

The feasibility of rapid genetic testing in patients undergoing percutaneous coronary intervention (PCI) and the comparison of the pharmacodynamic effects of prasugrel versus ticagrelor among carriers of cytochrome P450 2C19 loss-of-function alleles treated with PCI has been poorly explored. Rapid genetic testing using the Spartan assay was shown to be feasible and provides results in a timely fashion in a real-world setting of patients undergoing coronary angiography (n = 781). Among patients (n = 223, 28.5%), carriers of at least 1 loss-of-function allele treated with PCI (n = 65), prasugrel, and ticagrelor achieve similar levels of platelet inhibition. (A Pharmacodynamic Study Comparing Prasugrel Versus Ticagrelor in Patients Undergoing PCI With CYP2C19 Loss-of-function [NCT02065479]).

Pharmacodynamic Effects of Vorapaxar in Prior Myocardial Infarction Patients Treated With Potent Oral P2Y12 Receptor Inhibitors With and Without Aspirin: Results of the VORA-PRATIC Study

Background Vorapaxar as an adjunct to dual antiplatelet therapy (DAPT) reduces thrombotic events in patients with prior myocardial infarction at the expense of increased bleeding. Withdrawal of aspirin has emerged as a bleeding reduction strategy. The pharmacodynamic effects of vorapaxar with potent P2Y12 inhibitors as well as the impact of dropping aspirin is unexplored and represented the aim of the VORA-PRATIC (Vorapaxar Therapy in Patients With Prior Myocardial Infarction Treated With Newer Generation P2Y12 Receptor Inhibitors Prasugrel and Ticagrelor) study. Methods and Results Post-myocardial infarction patients (n=130) on standard DAPT (aspirin+prasugrel or ticagrelor) were randomized to 1 of 3 arms: (1) triple therapy: aspirin+prasugrel/ticagrelor+vorapaxar; (2) dual therapy (drop aspirin): prasugrel/ticagrelor+vorapaxar; (3) DAPT: aspirin+prasugrel/ticagrelor. Pharmacodynamic assessments were performed at 3 time points (baseline and 7 and 30 days). Vorapaxar reduced CAT (collagen-ADP-TRAP)-induced platelet aggregation, a marker of platelet-mediated global thrombogenicity (triple therapy versus DAPT at 30 days: mean difference=-27; 95% CI,-35 to -19; P<0.001; primary end point). This effect was attenuated but still significant in the absence of aspirin (dual therapy versus DAPT at 30 days: mean difference=-15; 95% CI,-23 to -7; P<0.001; between-group comparisons, P<0.05). Vorapaxar abolished TRAP-induced aggregation (P<0.001), without affecting thrombin generation and clot strength. There were no differences in markers of P2Y12 reactivity. Markers sensitive to aspirin-induced effects increased (P<0.001) in the dual-therapy arm. Conclusions In post-myocardial infarction patients treated with potent P2Y12 inhibitors, vorapaxar reduces platelet-driven global thrombogenicity, an effect that persisted, albeit attenuated, in the absence of aspirin and without affecting markers of P2Y12 reactivity or clot kinetics. The clinical implications of these PD observations warrant future investigation. Registration URL: https://www.clini​caltr​ials.gov. Unique identifier: NCT02545933.

Platelet Inhibition With Cangrelor and Crushed Ticagrelor in Patients With ST-Segment-Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

BACKGROUND

The platelet inhibitory effects induced by oral P2Y₁₂ receptor antagonists are delayed in patients with ST-segment-elevation myocardial infarction undergoing primary percutaneous coronary intervention (P-PCI). In turn, this leads to a gap in platelet inhibition, exposing patients to an increased risk of early thrombotic complications and underscoring the need to define strategies associated with more effective platelet inhibition in the peri-primary percutaneous coronary intervention period. Cangrelor is an intravenous P2Y₁₂ inhibitor with prompt and potent antiplatelet effects. However, to date, there are limited data on the effects of cangrelor used in combination with ticagrelor in patients undergoing primary percutaneous coronary intervention. Moreover, questions have emerged on the potential for drug-drug interactions during the transition from cangrelor to oral P2Y₁₂ inhibitors.

METHODS

This was a prospective, randomized, double-blind, placebo-controlled pharmacodynamic study conducted in patients undergoing primary percutaneous coronary intervention (n=50) who were randomized to treatment with either cangrelor or matching placebo (bolus followed by 2-hour infusion). All patients received ticagrelor 180-mg loading dose administered as crushed tablets at the time of cangrelor/placebo bolus administration. Pharmacodynamic analyses were performed at 8 time points. Pharmacodynamic effects were measured as P2Y₁₂ reaction units by VerifyNow and platelet reactivity index by vasodilator-stimulated phosphoprotein.

RESULTS

Compared with placebo, cangrelor was associated with reduced P2Y₁₂ reaction units as early as 5 minutes after bolus, which persisted during the entire duration of drug infusion, including at 30 minutes (63 [32-93] versus 214 [183-245]; mean difference, 152 [95% CI, 108-195]; P<0·001; primary end point). Parallel findings were shown with platelet reactivity index. Accordingly, high on-treatment platelet reactivity rates were reduced with cangrelor. After discontinuation of cangrelor/placebo infusion, there were no differences in levels of platelet reactivity between groups, ruling out a drug-drug interaction when cangrelor and ticagrelor are concomitantly administered.

CONCLUSIONS

In patients undergoing primary percutaneous coronary intervention, cangrelor is an effective strategy to bridge the gap in platelet inhibition associated with the use of oral P2Y₁₂ inhibition induced by ticagrelor. Ticagrelor can be administered as a crushed formulation concomitantly with cangrelor without any apparent drug-drug interaction. The clinical implications of these pharmacodynamic findings warrant investigation in an adequately powered clinical trial.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov . Unique identifier: NCT03247738.

164 Gonadotrophin-releasing hormone injection and colour flow Doppler ultrasound of the preovulatory follicle as a tool to increase pregnancy outcome after timed AI in beef cows

The aims of this study were to determine (1) the association between Doppler vascularisation scores (DVS) of the preovulatory follicle (POF) and fertility of beef cows submitted to timed AI (TAI) and (2) whether cows with low DVS benefit from a gonadotrophin-releasing hormone (GnRH) treatment at TAI. Multiparous lactating Nelore cows (Bos indicus; n=69) from a commercial beef farm in the state of Rondônia, Brazil, were enrolled in this study. Cows received 2mg of oestradiol benzoate intramuscularly (Bioestrogen, Biogénesis Bagó) and an intravaginal progesterone-releasing device (1.9g of progesterone; controlled internal drug release, CIDR) to synchronise follicular wave emergence on Day 0. The CIDR device was removed and cows were treated with 150μg of D-cloprostenol intramuscularly (prostaglandin F2α analogue; Croniben), 1mg of oestradiol cypionate intramuscularly, and 300IU of equine chorionic gonadotrophin (Novormon) intramuscularly on Day 8. Cows were then painted with a tail chalk marker to identify those displaying oestrus. All cows were submitted to TAI 48h after CIDR removal. At TAI, occurrence of oestrus was recorded and all cows were examined using transrectal ultrasonography. Blood flow of the POF was evaluated using colour Doppler imaging. Colour Doppler signals present on the follicular wall were subjectively scored using a 1-to-4 scale (1=absence or very low blood flow, and 4=intense blood flow detected on most of the follicular wall surface) adapted from Ginther (2007Ultrasonic Imaging and Animal Reproduction: Color-Doppler Ultrasonography, pages 87-114). Then, cows were divided into three groups according their DVS of the POF: (1) high DVS (DVS ≥3; n=36), (2) low DVS (DVS &lt;3; n=16), and (3) low DVS (DVS &lt;3; n=17) plus a GnRH treatment at TAI. The diameter of the POF was analysed using analysis of variance (PROC GLIMMIX of SAS; SAS Institute Inc.), and the means were compared among groups using Tukey's test. The proportion of cows that displayed oestrus and pregnancy rates was analysed using chi-square test. Cows in the high-DVS group had a larger POF than cows in the low-DVS and low-DVS-GnRH groups (13.2±0.2, 11.7±0.5, and 12.2±0.4, respectively; P&lt;0.05). The proportion of cows that displayed oestrus was greater (P&lt;0.05) in the high-DVS group (72%, 26/36) than in the low-DVS (37.5%, 6/16) or low-DVS-GnRH (53%, 9/17) groups. Finally, greater (P&lt;0.05) pregnancy rates were observed in cows from the high-DVS (47.2%; 17/36) and low-DVS-GnRH (52.9%; 9/17) groups than in cows from the low-DVS group (18.7%; 3/16). The preliminary results from this study demonstrated that diameter of POF is positively associated with DVS. Moreover, cows that presented POF with higher DVS are more likely to become pregnant, and the administration of GnRH to females with low DVS can increase the fertility of beef cows submitted to TAI protocols. This study received funding support from Embrapa (MP1/PC3 project no. 01.03.14.011.00.00) and from CNPq (universal project no. 407307/2016-8).

P1930Pharmacodynamic effects of vorapaxar as an add-on antiplatelet therapy in patients with and without diabetes mellitus: the optimizing anti-platelet therapy in diabetes mellitus (OPTIMUS)-5 study

Background

Vorapaxar (Vora) is a protease-activated receptor (PAR)-1 inhibitor which when added to dual antiplatelet therapy (DAPT) in patients with a history of myocardial infarction (MI) or with peripheral arterial (PAD) reduces thrombotic cardiovascular events at the expense of increased bleeding. The efficacy of Vora is enhanced in patients with diabetes mellitus (DM) compared to non-DM. However, the differential pharmacodynamic (PD) effects of Vora in DM vs non-DM patients are unknown. Moreover, although withdrawal of aspirin has emerged as a strategy to reduce bleeding when adjunctive antithrombotic therapies are used, the PD effects of Vora after stopping aspirin in DAPT treated patients is unknown.

Purpose

To assess the PD effects of Vora in addition to standard DAPT as well as in combination with clopidogrel following aspirin withdrawal in patients with and without DM.

Methods

This was a prospective parallel-design PD study conducted in post-MI or PAD patients with and without DM. Patients on DAPT with aspirin (81mg/qd) and clopidogrel (75mg/qd) were divided in two groups according to DM status. Each cohort was treated with Vora (2.5mg/qd) in addition to DAPT (i.e., triple therapy) for 30 days and afterwards stopped aspirin and maintained treatment with Vora plus clopidogrel (i.e., dual therapy) for other 30 days. PD testing using 5 different assays was conducted at 3 time-points: baseline (while on DAPT); after 30 days of triple therapy; after 30 days of dual therapy. The primary endpoint was the non-inferiority of CAT (Collagen-ADP-TRAP)-induced aggregation, a marker of global platelet reactivity, of Vora plus clopidogrel (dual therapy) vs Vora plus DAPT (triple therapy).

Results

The PD population was composed of a total of 64 patients (DM, n=30; non-DM, n=34). Although adding Vora to DAPT significantly reduced CAT-induced aggregation, stopping aspirin was associated with an increase in CAT-induced aggregation in both DM (mean difference=12; 95% CI: 3 to 21; p=0.010) and non-DM (mean difference=10; 95% CI: 4 to 16; p=0.003), thus not meeting the primary endpoint of non-inferiority (Figure). The magnitude of such increase was higher in DM compared with non-DM (p=0.036). Although Vora abolished TRAP-induced aggregation in both DM and non-DM patients, it did not affect markers of clot kinetics including speed of thrombin generation. Aspirin withdrawal was associated with a marked increase in makers sensitive to cyclooxygenase-1 (COX-1) blockade; markers of P2Y12 signaling were higher in DM compared to not DM after aspirin withdrawal.

CAT-induced aggregation

Conclusion

Adjunctive treatment with Vora reduces platelet-mediated thrombogenicity without affecting clot kinetics in both DM and non-DM patients while on DAPT. However, platelet-mediated thrombogenicity is increased after aspirin withdrawal, a phenomenon which is enhanced in DM patients underscoring the pivotal contribution of the COX-1 signaling pathway in these high risk patients.

Acknowledgement/Funding

The study was supported in part by an investigator initiated study grant from Merck

P1934Platelet inhibitory profiles of prasugrel versus ticagrelor in patients with CYP2C19 loss-of-function genotypes undergoing percutaneous coronary intervention: results of a randomized feasibility study

Background

Although clopidogrel is the most widely used P2Y12 inhibitor, loss-of-function (LOF) allelic variants located within the hepatic cytochrome P450 (CYP) 2C19 gene lead to attenuated bioactivation, increased rates of high platelet reactivity (HPR), and worse outcomes in patients undergoing percutaneous coronary intervention (PCI). Drug regulating authorities have suggested using alternative P2Y12 inhibitors (i.e., prasugrel or ticagrelor) in these patients. However, tailoring antiplatelet therapy in clinical practice according to results of genetic testing has been limited due to lack of access to promptly available results. Moreover, there are no head-to-head pharmacodynamic (PD) comparisons of prasugrel vs ticagrelor among patients with CYP2C19 LOF alleles.

Purpose

The aim of this study was to evaluate the feasibility of using rapid genetic testing in clinical practice and to compare the PD effects of prasugrel vs ticagrelor in patients undergoing PCI with CYP2C19 LOF alleles.

Methods

This was a prospective, randomized study conducted in patients with stable coronary artery disease and non-ST elevation acute coronary syndrome scheduled for left heart catheterization (LHC) with the intent to undergo PCI. Patients underwent rapid genetic testing using the Spartan RX assay, which defines CYP2C19 genetic status within 1 hour, allowing patients to be genotyped the same day of their LHC. Patients who were carriers of at least one LOF (*2 or *3) allele were randomized to receive either prasugrel [60mg loading dose (LD) - 10mg/day maintenance dose (MD)] or ticagrelor (180mg LD - 90mg b.i.d MD). Blood samples for PD analysis by VerifyNow were collected at 5 time points: baseline (prior to PCI), 30 minutes, 2 hours, 24 hours (or at hospital discharge whichever came first), and 1–4 weeks post-LD. All patients were treated with aspirin. The primary endpoint of our study was the non-inferiority in platelet reactivity, measured as PRU, at 24 hours of prasugrel vs ticagrelor in LOF allele carriers.

Results

A total of 781 consecutive patients scheduled for LHC were genotyped, of whom 223 (28.5%) were carriers of at least one LOF. Of these, 65 patients underwent PCI and randomized to prasugrel (n=32) vs ticagrelor (n=33). PRU levels at 24 hours were 33 vs 36 (prasugrel vs ticagrelor; mean difference = −3; 95% CI: −28 to 22; p=0.814) meeting the primary endpoint of non-inferiority. Both prasugrel and ticagrelor significantly reduced PRU to a similar extent with no differences between groups at all other time points (Figure). Accordingly, HPR rates were low and similar between groups.

PRU by VerifyNow

Conclusion

Rapid genetic testing using the Spartan assay is feasible providing results in a timely fashion in a real-world clinical practice of patients undergoing PCI. Among patients with CYP2C19 LOF carrier status, prasugrel and ticagrelor are associated with similar levels of platelet inhibition.

Acknowledgement/Funding

Genetic testing was provided by Spartan RX

Antiproliferative activity and p53 upregulation effects of chalcones on human breast cancer cells

Chalcones are valuable structures for drug discovery due to their broad bioactivity spectrum. In this study, we evaluated 20 synthetic chalcones against estrogen-receptor-positive breast cancer cells (MCF-7 line) and triple-negative breast cancer (TNBC) cells (MDA-MB-231 line). Antiproliferative screening by MTT assay resulted in two most active compounds: 2-fluoro-4’-aminochalcone (11) and 3-pyridyl-4’-aminochalcone (17). Their IC₅₀ values ranged from 13.2 to 34.7 µM against both cell lines. Selected chalcones are weak basic compounds and maintained their antiproliferative activity under acidosis conditions (pH 6.7), indicating their resistance to ion-trapping effect. The mode of breast cancer cells death was investigated and chalcones 11 and 17 were able to induce apoptosis rather than necrosis in both lines. Antiproliferative target investigations with MCF-7 cells suggested 11 and 17 upregulated p53 protein expression and did not affect Sp1 protein expression. Future studies on chalcones 11 and 17 can define their in vivo therapeutic potential.