Coronary Stenosis and Cardiogenic Shock Secondary to Aortitis Following Aortic Root Support Procedure.

A woman with recent personalized external aortic root support implant presented in cardiogenic shock with bilateral coronary ostial occlusion and aortic inflammation requiring emergency coronary angioplasty. Subsequent computed tomography with positron emission tomography scanning demonstrated aortitis with extensive inflammation adjacent to the personalized external aortic root support mesh, the first report of this important complication.

Percutaneous Left Ventricular Unloading During High-Risk Coronary Intervention: Rationale and Design of the CHIP-BCIS3 Randomized Controlled Trial.

INTRODUCTION: Percutaneous coronary intervention for complex coronary disease is associated with a high risk of cardiogenic shock. This can cause harm and limit the quality of revascularization achieved, especially when left ventricular function is impaired at the outset. Elective percutaneous left ventricular unloading is increasingly used to mitigate adverse events in patients undergoing high-risk percutaneous coronary intervention, but this strategy has fiscal and clinical costs and is not supported by robust evidence. METHODS: CHIP-BCIS3 (Controlled Trial of High-Risk Coronary Intervention With Percutaneous Left Ventricular Unloading) is a prospective, multicenter, open-label randomized controlled trial that aims to determine whether a strategy of elective percutaneous left ventricular unloading is superior to standard care (no planned mechanical circulatory support) in patients undergoing nonemergent high-risk percutaneous coronary intervention. Patients are eligible for recruitment if they have severe left ventricular systolic dysfunction, extensive coronary artery disease, and are due to undergo complex percutaneous coronary intervention (to the left main stem with calcium modification or to a chronic total occlusion with a retrograde approach). Cardiogenic shock and acute ST-segment-elevation myocardial infarction are exclusions. The primary outcome is a hierarchical composite of all-cause death, stroke, spontaneous myocardial infarction, cardiovascular hospitalization, and periprocedural myocardial infarction, analyzed using the win ratio. Secondary outcomes include completeness of revascularization, major bleeding, vascular complications, health economic analyses, and health-related quality of life. A sample size of 250 patients will have in excess of 80% power to detect a hazard ratio of 0.62 at a minimum of 12 months, assuming 150 patients experience an event across all follow-up. CONCLUSIONS: To date, 169 patients have been recruited from 21 National Health Service hospitals in the United Kingdom, with recruitment expected to complete in 2024. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT05003817.

CMR reclassifies the majority of patients with suspected MINOCA and non MINOCA.

AIMS: In ∼5-15% of all cases of acute coronary syndromes (ACS) have unobstructed coronaries on angiography. Cardiac magnetic resonance (CMR) has proven useful to identify in most patients the underlying diagnosis associated with this presentation. However, the role of CMR to reclassify patients from the initial suspected condition has not been clarified. The aim of this study was to assess the proportion of patients with suspected MINOCA, or non-MINOCA, that CMR reclassifies with an alternative diagnosis from the original clinical suspicion. METHODS AND RESULTS: A retrospective cohort of patients in a tertiary cardiology centre was identified from a registry database. Patients who were referred for CMR for investigation of suspected MINOCA, and a diagnosis pre- and post-CMR was recorded to determine the proportion of diagnoses reclassified. A total of 888 patients were identified in the registry. CMR reclassified diagnosis in 78% of patients. Diagnosis of MINOCA was confirmed in only 243 patients (27%), whilst most patients had an alternative diagnosis (73%): myocarditis n = 217 (24%), Takotsubo syndrome n = 115 (13%), cardiomyopathies n = 97 (11%), and normal CMR/non-specific n = 216 (24%). CONCLUSION: In a large single-centre cohort of patients presenting with ACS and unobstructed coronary arteries, most patients had a non-MINOCA diagnosis (73%) (myocarditis, Takotsubo, cardiomyopathies, or normal CMR/non-specific findings), whilst only a minority had confirmed MINOCA (27%). Performing CMR led to reclassifying patients' diagnosis in 78% of cases, thus confirming its important clinical role and underscoring the clinical challenge in diagnosing MINOCA and non MINOCA conditions.

Intravascular lithotripsy for treatment of calcific coronary lesions in ST elevation myocardial infarction.

AIMS: To describe the utility and safety of intravascular lithotripsy (IVL) in the setting of primary percutaneous coronary intervention (PCI) for ST elevation myocardial infarction (STEMI). METHODS AND RESULTS: We performed a retrospective analysis, across six UK sites of all patients in whom IVL was used for coronary calcium modification of the culprit lesion during primary PCI for STEMI. The 72 patients were included. IVL was used in de-novo culprit lesions in 57 (79%) of cases and culprit in-stent restenoses in 11 (15%) of cases. In four cases (6%) it was used in a newly deployed stent when this was under-expanded due to inadequate calcium modification. Of the 30 cases in which intracoronary imaging was available for stent analysis, the average stent expansion was 104%. Intra-procedural stent thrombosis occurred in one case (1%), and no-reflow in three cases (4%). The 30 day MACE rates were 18%. CONCLUSION: IVL appears to be feasible and safe for use in the treatment of calcific coronary artery disease in the setting of STEMI.

Factors Influencing Stent Failure in Chronic Total Occlusion Coronary Intervention.

Stent failure remains one of the greatest challenges for interventional cardiologists. Despite the evolution to superior second- and third-generation drug-eluting stent designs, increasing use of intracoronary imaging and the adoption of more potent antiplatelet regimens, registries continue to demonstrate a prevalence of stent failure or target lesion revascularisation of 15-20%. Predisposition to stent failure is consistent across both chronic total occlusion (CTO) and non-CTO populations and includes patient-, lesion- and procedure-related factors. However, histological and pathophysiological properties specific to CTOs, alongside complex strategies to treat these lesions, may potentially render percutaneous coronary interventions in this cohort more vulnerable to failure. Prevention requires recognition and mitigation of the precipitants of stent failure, optimisation of interventional techniques, including image-guided precision percutaneous coronary intervention, and aggressive modification of a patient's cardiovascular risk factors. Management of stent failure in the CTO population is technically challenging and itself begets recurrence. We aim to provide a comprehensive review of factors influencing stent failure in the CTO population and strategies to attenuate these.

Long-term outcome of myocardial scarring and deformation with cardiovascular magnetic resonance in out of hospital cardiac arrest survivors.

AIMS: Cardiovascular magnetic resonance (CMR) is increasingly recognized as a diagnostic and prognostic tool in out of hospital cardiac arrest (OHCA) survivors. After assessing CMR findings early after ventricular fibrillation (VF) OHCA, we sought to explore the long-term outcome of myocardial scarring and deformation. METHODS AND RESULTS: We included 121 consecutive VF OHCA survivors (82% male, median 62 years) undergoing CMR within 2 weeks from cardiac arrest. Late gadolinium-enhancement (LGE) was quantified using the full width at half maximum method and tissue tracking analysis software was used to assess myocardial deformation. LGE was found in 71% of patients (median LGE mass 6.2% of the left ventricle, LV), mainly with an ischaemic pattern. Myocardial deformation was overall impaired and showed a significant correlation with LGE presence and extent (P < 0.001). A composite end-point of all-cause mortality and appropriate ICD discharge/anti-tachycardia pacing was met in 24% of patients. Patients meeting the end-point had significantly greater LGE extent (8.6% of LV myocardium vs. 4.1%, P = 0.02), while there was no difference with regards to myocardial deformation. Survival rate was significantly lower in patients with LGE (P = 0.05) and LGE mass >4.4% of the LV identified a group of patients at higher risk of adverse events (P = 0.005). CONCLUSIONS: We found a high prevalence of LGE, early after OHCA, and an overall impaired myocardial deformation. On long-term follow-up both LGE presence and extent showed a significant association with recurrent adverse events, while LV ejection fraction and myocardial deformation did not identify patients with an unfavourable outcome.

Intravascular Healing Is Not Affected by Approaches in Contemporary CTO PCI: The CONSISTENT CTO Study.

OBJECTIVES: The aim of this study was to assess angiographic, imaging, and clinical outcomes following chronic total occlusion (CTO) percutaneous coronary intervention (PCI) with dissection and re-entry techniques (DART) and subintimal (SI) stenting compared with intimal techniques. BACKGROUND: Reliable procedural success and safety in CTO PCI require the use of DART to treat the most complex patients. Potential concerns regarding the durability of DART with SI stenting still need to be addressed. METHODS: This was a prospective, multicenter, single-arm trial of patients with appropriate indications for CTO PCI. RESULTS: Successful CTO PCI was performed in 210 of 231 patients (91% success). At 1 year, the primary endpoint of target vessel failure (cardiac death, myocardial infarction related to the target vessel, or any ischemia-driven revascularization) occurred in 5.7% of patients, meeting the pre-set performance goal. Major adverse cardiovascular events (all-cause mortality, myocardial infarction, or target vessel revascularization) occurred in 10% at 1 year and 17% by 2 years and was not influenced by DART. Quality-of-life measures significantly improved from baseline to 12 months. There was no difference in intravascular healing assessed using optical coherence tomography at 12 months for patients treated with DART and SI stenting compared with intimal strategies. CONCLUSIONS: Contemporary CTO PCI is associated with medium-term clinical outcomes comparable with those achieved in other complex PCI cohorts and significant improvements in quality of life. The use of DART with SI stenting does not adversely affect intravascular healing at 12 months or medium-term major adverse cardiovascular events. (Consistent CTO Trial; NCT02227771).

Incidence of "shocktopics" and asynchronous cardiac pacing in patients undergoing coronary intravascular lithotripsy.

AIMS: Coronary intravascular lithotripsy (IVL) is a novel approach to vascular calcium modification that restores vessel compliance allowing effective lesion expansion. In this study we report the capacity for coronary IVL to precipitate ventricular ectopics ("shocktopics") and asynchronous cardiac pacing. METHODS AND RESULTS: This was a retrospective review of all cases of coronary IVL (n=54) undertaken in the Royal Victoria Hospital, Belfast, between September 2018 and March 2019. The indication for PCI was chronic stable angina in 46.1% (n=26), non-ST-elevation acute coronary syndrome (NSTEACS) in 33.3% (n=18) and ST-elevation myocardial infarction (STEMI) in 18.5% (n=10) of patients. The incidence of coronary IVL-provoked ventricular capture was 77.8% (n=42). Multivariable logistic regression analysis identified heart rate as the only independent predictor of an increased risk of IVL-induced ventricular capture. Patients with a heart rate <65 bpm prior to IVL were sixteen-fold more likely (OR 16.3 [2.4-110.8], p=0.004) to experience events compared to patients with a heart rate ≥65 bpm. "Shocktopic" beat morphology was largely uniform in each patient and appeared dependent on the target lesion location, in keeping with mechano-electric coupling through activation of local stretch-activated cardiomyocyte channels. No adverse clinical events occurred as a result of coronary IVL-induced capture. CONCLUSIONS: Coronary IVL with the Shockwave Medical system is associated with a high incidence of "shocktopics" and asynchronous cardiac pacing that is largely dependent on the resting heart rate. There have been no clinical events associated with this phenomenon, but further systematic evaluation is warranted.

Case-Based Review of the Current Global Evidence Supporting Impella-Facilitated Complex and Complete Revascularization.

A 74-year-old male patient who was admitted with non-ST-segment elevation myocardial infarction, severe left ventricular impairment, severe mitral regurgitation, and full viability who was turned down for surgery underwent high-risk and indicated multivessel stenting with Impella (Abiomed) support. At 6-month follow-up he was angina free, with complete resolution of the mitral regurgitation. (Level of Difficulty: Intermediate.).

Bivalirudin versus heparin in primary PCI: clinical outcomes and cost analysis.

Background: The evidence for benefits of bivalirudin over heparin has recently been challenged. We aimed to analyse the safety and cost-effectiveness following reintroduction of heparin instead of bivalirudin as the standard anticoagulation for primary percutaneous coronary intervention (PPCI) in a high-volume centre. Methods and results: This analysis was an open-label, prospective registry including all patients admitted to our centre for PPCI from April 2014 to April 2016. Heparin was reintroduced as standard anticoagulant in April 2015. During the 2 years, 1291 patients underwent a PPCI, 662 in the Bivalirudin protocol period (Cohort B) and 629 in the Heparin protocol period (Cohort H). Baseline and procedural characteristics were not significantly different, except for a higher use of thromboaspiration and femoral access in the earlier Cohort B. Glycoprotein 2b3a (Gp2b3a) antagonists were used in 24% of the patients in Cohort B versus 28% in Cohort H (P<0.01). We did not observe any differences in death at 180 days (11.03% in Cohort B vs 11.29% in Cohort H)(HR 95% CI 0.98 (0.72 to 1.33), P=0.88). The incidence of any bleeding complications at 30 days did not differ between the two periods (21.9% vs 21.9%, P=0.99). The cost related to the anticoagulants amounted to £246 236 in Cohort B versus £4483 in Cohort H (£324 406 vs £102 347 when adding Gp2b3a antagonists). Conclusion: We did not find clinically relevant changes in patient outcomes, including bleeding complications with reintroduction of heparin in our PPCI protocol. However, the use of heparin was associated with a major reduction in treatment costs.

Towards a contemporary, comprehensive scoring system for determining technical outcomes of hybrid percutaneous chronic total occlusion treatment: The RECHARGE score.

OBJECTIVES: This study sought to create a contemporary scoring tool to predict technical outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI) from patients treated by hybrid operators with differing experience levels. BACKGROUND: Current scoring systems need regular updating to cope with the positive evolutions regarding materials, techniques, and outcomes, while at the same time being applicable for a broad range of operators. METHODS: Clinical and angiographic characteristics from 880 CTO-PCIs included in the REgistry of CrossBoss and Hybrid procedures in FrAnce, the NetheRlands, BelGium and UnitEd Kingdom (RECHARGE) were analyzed by using a derivation and validation set (2:1 ratio). Variables significantly associated with technical failure in the multivariable analysis were incorporated in the score. Subsequently, the discriminatory capacity was assessed and the validation set was used to compare with the J-CTO score and PROGRESS scores. RESULTS: Technical success in the derivation and validation sets was 83% and 85%, respectively. Multivariate analysis identified six parameters associated with technical failure: blunt stump (beta coefficient (b) = 1.014); calcification (b = 0.908); tortuosity ≥45° (b = 0.964); lesion length 20 mm (b = 0.556); diseased distal landing zone (b = 0.794), and previous bypass graft on CTO vessel (b = 0.833). Score variables remained significant after bootstrapping. The RECHARGE score showed better discriminatory capacity in both sets (area-under-the-curve (AUC) = 0.783 and 0.711), compared to the J-CTO (AUC = 0.676) and PROGRESS (AUC = 0.608) scores. CONCLUSIONS: The RECHARGE score is a novel, easy-to-use tool for assessing the risk for technical failure in hybrid CTO-PCI and has the potential to perform well for a broad community of operators. © 2017 Wiley Periodicals, Inc.

Safety and efficacy of the hybrid approach in coronary chronic total occlusion percutaneous coronary intervention: The Hybrid Video Registry.

OBJECTIVES: The aim of the Hybrid Video Registry (HVR) is to assess the acute safety and efficacy of the Hybrid Approach in comparison to other contemporary methods of CTO-PCI. BACKGROUND: Recently, multiple techniques in Percutaneous Coronary Intervention (PCI) for coronary Chronic Total Occlusions (CTO) have been synthesized into a method referred to as the "Hybrid Approach". METHODS: About 194 video-taped timed live cases from CTO-PCI training workshops were analyzed by independent data abstractors and compared to three contemporary CTO-PCI registries stratified by case complexity based on the J-CTO score. RESULTS: Overall procedural success was 95% of all cases attempted with an excellent safety profile. In the most complex lesion subset, which made up 45% of all HVR cases, success was 92.8%, which was significantly higher than either the Royal Bromptom (78.9%), or Japanese-CTO (73.3%) registries, P = 0.04 Hybrid vs. Royal Brompton, P = 0.006 Hybrid vs. Japanese-CTO). The Hybrid Approach was also associated with shorter procedure times and lower contrast utilization. CONCLUSIONS: In a real world angiographic registry of complex CTOs, the Hybrid Approach to CTO-PCI is safe, and may be superior to other contemporary approaches to CTO intervention with respect to procedural success and efficiency among a diverse group of operators and lesion complexity. © 2017 Wiley Periodicals, Inc.

Fully Transradial Versus Transfemoral Approach for Percutaneous Intervention of Coronary Chronic Total Occlusions Applying the Hybrid Algorithm: Insights From RECHARGE Registry.

BACKGROUND: Small observational studies demonstrate the feasibility of transradial approach for chronic total occlusion (CTO) percutaneous coronary intervention. The aim of the current study is to assess technical success, complication rates, and procedural efficiency in fully transradial approach (fTRA) and transfemoral approach (TFA) in a large prospective European registry adopting the hybrid algorithm for CTO percutaneous coronary intervention (Registry of CrossBoss and Hybrid Procedures in France, the Netherlands, Belgium and United Kingdom, RECHARGE registry). METHODS AND RESULTS: We analyzed 1253 CTO percutaneous coronary intervention procedures performed according to the hybrid protocol in 17 European centers, comparing fTRA (single or biradial access) and TFA (single or bifemoral or combined radial and femoral access). fTRA was applied in 306 (24%) and TFA in 947 (76%) cases. The average Japanese CTO score was 2.1±1.2 in fTRA and 2.3±1.1 in TFA (P=0.06). Technical success was achieved in 85% in fTRA and 86% in TFA (P=0.51). Technical success was comparable for fTRA and TFA in different Japanese CTO score subgroups after multivariable analysis and after propensity adjustment. In-hospital major adverse cardiac and cerebral events occurred in 2.0% in fTRA and 2.9% in TFA (P=0.40). Major access site bleeding occurred in 0.3% in fTRA and 0.5% in TFA (P=0.66). fTRA compared with TFA had similar procedural duration (80 minutes [54-120 minutes] versus 90 minutes [60-121 minutes]; P=0.07), similar radiation dose (dose area product 89 Gray×cm2 [52-163 Gray×cm2] versus 101 Gray×cm2 [59-171 Gray×cm2]; P=0.06), and lower contrast agent use (200 mL [150-310 mL] versus 250 mL [200-350 mL]; P<0.01). CONCLUSIONS: fTRA CTO percutaneous coronary intervention is a valid alternative to TFA with a high rate of success, low complication rates, and no decrease in procedural efficiency.

Single-centre experience of STENTYS Xposition S in treatment of left main stem lesions.

BACKGROUND: The second generation STENTYS Xposition S self-expanding stent with a novel balloon delivery system was launched in May 2015. The stents unique properties are well suited for the treatment of left main stem disease where large diameters, coverage of diameter differences and precise positioning are required. We report the first consecutive experience of using this device in the treatment of left main stem lesions. METHODS: 20 consecutive patients with a mean age of 73.9±10.1 years were treated over a period of 8 months at our institution and were assessed on the parameters of technical, angiographic and procedural success. RESULTS: Technical success was achieved in 95% of cases and angiographic success in 80% of cases. There was no incidence of geographical miss. Side branch access was straightforward, with no failure to recross stent struts, dilate or deploy a second stent if required. In this unselected clinical cohort, 2 critically ill patients with cardiogenic shock on presentation died despite successful revascularisation. There was no incidence of early stent related complications up to 30-day follow up. CONCLUSION: This first consecutive series of left main lesions treated with STENTYS Xposition S documents high acute technical and procedural success rates.

Primary percutaneous coronary intervention of native chronic total occlusions to treat ST elevation myocardial infarction secondary to acute vein graft occlusion.

Primary percutaneous coronary intervention (PCI) is the treatment modality of choice in patients presenting with ST elevation myocardial infarction (STEMI). Clinical outcomes have dramatically improved with the wide adoption of primary PCI in patients with STEMI because of acute thrombotic native coronary artery occlusion. However, patients with prior coronary artery bypass graft (CABG) surgery who present with STEMI because of acute saphenous vein graft (SVG) occlusion continue to have worse outcomes because of poor acute and long-term results of SVG stenting. Therefore, it may be preferable to treat the native coronary artery supplied by the occluded graft although this can be challenging if the native vessel is a chronic total occlusion (CTO). Recent advances in technology and techniques in CTO PCI have significantly improved the success rate and efficiency of CTO procedures. At our institution we have developed a high volume CTO programme with high success rates. We present three cases of acute inferior STEMI because of SVG occlusion which were treated with successful retrograde PCI of the native vessel CTO, utilising the occluded graft as a retrograde channel in two cases and native septal collaterals in the other. Thrombolysis In Myocardial Infarction (TIMI) 3 flow in the native coronary artery was achieved in all three cases with good acute outcomes. Our case series highlights the benefits of a high volume CTO programme. With recent advances in CTO techniques, acute PCI to native vessel CTO is feasible and may be the treatment of choice in selected cases of acute SVG failure. © 2017 Wiley Periodicals, Inc.

Selective use of contemporary drug-eluting stents in primary angioplasty for ST-elevation myocardial infarction: pooled analysis of COMFORTABLE AMI and EXAMINATION.

AIMS: Selective use of DES only in patients at higher risk of MACE is common practice, particularly in healthcare systems with a large premium payable for DES. We aimed to identify subgroups of patients in which the use of BMS in primary percutaneous coronary intervention (PPCI) for STEMI can still be justified. METHODS AND RESULTS: We performed a patient-level pooled analysis of COMFORTABLE AMI and EXAMINATION comparing contemporary DES with BMS in PPCI. A risk score was applied using three parameters: lesion length >15 mm, vessel size <3 mm, and diabetes mellitus. Individual data were available for 2,655 patients. The incidence of MACE at one year was incrementally higher in patients with risk scores of 1 or 2/3. MACE rates were lower in patients with a risk score 0 or 1 who were treated with DES (p=0.0073 and p=0.008). No difference in death or reinfarction was seen between DES and BMS in any group. There was a significant reduction in TLR with DES in all three groups. CONCLUSIONS: A score comprising vessel size, lesion length, and diabetes did not identify patients at low risk with equivalent or better results from BMS use. The results suggest that the practice of only selective use of DES in primary PCI should be discouraged.

The Hybrid Algorithm for Treating Chronic Total Occlusions in Europe: The RECHARGE Registry.

BACKGROUND: The hybrid algorithm for chronic total occlusion (CTO) percutaneous coronary intervention (PCI) was developed to improve procedural outcomes. Large, prospective studies validating the algorithm in a broad multicenter setting with operators of different experience levels are lacking. OBJECTIVES: The RECHARGE (REgistry of Crossboss and Hybrid procedures in FrAnce, the NetheRlands, BelGium and UnitEd Kingdom) registry aims to report achievable results using the hybrid algorithm. METHODS: Between January 2014 and October 2015, consecutive patients undergoing hybrid CTO-PCI were prospectively enrolled in 17 centers. Procedural techniques, outcomes, and in-hospital complications were analyzed. RESULTS: A total of 1,253 CTO-PCIs were performed in 1,177 patients, of which 86% were men. Mean age was 66 ± 11 years. The average Japanese CTO score was 2.0 ± 1.0, and was higher in the failure group (2.6 ± 0.6 vs. 1.9 ± 1.0; p < 0.001). Overall procedure success was 86% and major in-hospital complications occurred in 2.6%. Antegrade wire escalation was the preferred primary strategy in 77%, followed by retrograde (17%) and antegrade dissection re-entry strategies (7%). Primary strategies were successful in 60%. Consecutive strategies were applied in 34% and were successful in 74%. Antegrade dissection re-entry and retrograde strategies were the most common bailout strategies and were successful in 67% and 62%, respectively. Median procedure and fluoroscopy time were 90 (interquartile range [IQR]: 60 to 120) min and 35 (IQR: 21 to 55) min, contrast volume was 250 (IQR: 180 to 340) ml, and radiation doses (air kerma and dose area product) were 1.6 (IQR: 1.0 to 2.7) Gy and 98 (IQR: 57 to 168) Gy·cm2, respectively. CONCLUSIONS: High procedure and patient success rates, combined with a low event rate and improved procedural characteristics, support further use of the hybrid algorithm for a broad community of appropriately trained CTO operators.

A Study of Platelet Inhibition, Using a 'Point of Care' Platelet Function Test, following Primary Percutaneous Coronary Intervention for ST-Elevation Myocardial Infarction [PINPOINT-PPCI].

BACKGROUND: Rapid coronary recanalization following ST-elevation myocardial infarction (STEMI) requires effective anti-platelet and anti-thrombotic therapies. This study tested the impact of door to end of procedure ('door-to-end') time and baseline platelet activity on platelet inhibition within 24hours post-STEMI. METHODS AND FINDINGS: 108 patients, treated with prasugrel and procedural bivalirudin, underwent Multiplate® platelet function testing at baseline, 0, 1, 2 and 24hours post-procedure. Major adverse cardiac events (MACE), bleeding and stent thrombosis (ST) were recorded. Baseline ADP activity was high (88.3U [71.8-109.0]), procedural time and consequently bivalirudin infusion duration were short (median door-to-end time 55minutes [40-70] and infusion duration 30minutes [20-42]). Baseline ADP was observed to influence all subsequent measurements of ADP activity, whereas door-to-end time only influenced ADP immediately post-procedure. High residual platelet reactivity (HRPR ADP>46.8U) was observed in 75% of patients immediately post-procedure and persisted in 24% of patients at 2hours. Five patients suffered in-hospital MACE (4.6%). Acute ST occurred in 4 patients, all were <120mins post-procedure and had HRPR. No significant bleeding was observed. In a post-hoc analysis, pre-procedural morphine use was associated with significantly higher ADP activity following intervention. CONCLUSIONS: Baseline platelet function, time to STEMI treatment and opiate use all significantly influence immediate post-procedural platelet activity.