Operator radiation exposure in the cardiac catheterisation laboratory: does biplane angiography increase radiation dose?

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406 Non-thrombogenic, bioactive stent platform S. Wise 1,2,∗ , P. Michael 1 , M. Santos 1,3 , E. Filipe 1,2 , T. Jeewandara 1,2 , J. Hung 1 , A. Kondyurin 3 , A. Weiss 4,5 , M. Bilek 3 , M. Ng 1,2,6 1 The

Heart Research Institute, Sydney, NSW, Australia 2 Sydney Medical School, University of Sydney, NSW, Australia 3 School of Physics, University of Sydney, NSW, Australia 4 School of Molecular Bioscience, University of Sydney, NSW, Australia 5 Charles Perkins Centre, University of Sydney, NSW, Australia 6 Department of Cardiology, Royal Prince Alfred Hospital, Camperdown, NSW Australia This abstract has been withheld from publication http://dx.doi.org/10.1016/j.hlc.2015.06.407 407 One-shot circumferential renal artery denervation with relative sparing of the arterial wall may be possible using a novel microwave catheter P. Qian 1,2,∗ , T. Barry 1,3 , S. Al-Raisi 1,2 , P. Kovoor 1,2 , A. McEwan 1,3 , A. Thiagalingam 1,2 , S. Thomas 1,2 1 Department of Cardiology, Westmead Hospital, Camperdown, NSW Australia 2 Sydney Medical School, University of Sydney, NSW Australia 3 Faculty of Electrical and Information Engineering, University of Sydney, NSW Australia

Background: Recent clinical trials of renal artery denervation using radiofrequency ablation have not showed consistent effect on blood pressure reduction. Aim: To demonstrate that a novel microwave catheter can potentially induce vessel sparing circumferential denervation without significant heating of nearby viscera. Methods: A microwave catheter capable of radiant heating was constructed and tested in a renal artery model. The renal artery model consisted of transparent phantom materials embedded with a thermochromic liquid crystal sheet that changes colour with temperatures between 50–78 ◦ C. 0.9% saline was perfused through the renal artery at 37 ◦ C. 25,200 J ablations were performed at 140 W for 180 s and 120 W for 210 s with saline flow at 0.5L/min and 0.1 L/min. Lesion dimensions were assessed using serial digital photography and analysed with in-house built software. Results: Ablations at 140 W and 0.5 L/min flow spared the luminal 1.0 mm (95% CI 0.8–1.1 mm) of the vessel wall,

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extended 5.9 mm (95% CI 5.5–6.1 mm) deep from the vessel lumen and was 19.2 mm in length (95% CI 17.7–20.7 mm). Reductions in renal artery flow to 0.1 L/min had minimal impact on lesion dimensions. Delivering ablation energy slower using 120 W for 210 s at 0.5 L/min produced significantly smaller lesions with more vessel sparing compared with 140 W for 180 s at 0.5 L/min. No heating peripheral to the 10mm thick perinephric fat phantom layer was observed. Conclusions: We demonstrate as proof of principle that intravascular microwave ablation can induce circumferential heating to depths which encompass the majority of renal nerves while potentially sparing the renal artery intima and media as well as nearby viscera. http://dx.doi.org/10.1016/j.hlc.2015.06.408 408 Operator radiation exposure in the cardiac catheterisation laboratory: does biplane angiography increase radiation dose? D. Murdoch 1,2,∗ , J. Crowhurst 1,2 , E. Shaw 1,3 , R. Saireddy 1 , O. Raffel 1,2 , D. Walters 1,2 1 The

Prince Charles Hospital, Chermside, QLD, Australia 2 The University of Queensland, Brisbane, QLD, Australia 3 The University of Sydney, Sydney, NSW, Australia Biplane fluoroscopy has several advantages over singleplane imaging, including reduced contrast volume administration and procedure time. However, patient radiation dose is increased. We hypothesise that this may translate into higher radiation dose for the operator, which would deter routine use of biplane imaging. A novel radiation dose monitor (Instadose, Mirion Technologies, Georgia, USA) was worn on the lead collar by the operator and interrogated after each case. Operator dose (␮Sv) was recorded in a prospectively collected database, along with procedure type, single plane or biplane fluoroscopy, contrast volume and patient radiation dose data. 670 patients were included in the study, between August 2014 and November 2014. 501 underwent diagnostic coronary angiography (423 single plane, 78 biplane) and 169 had coronary angiography plus PCI (143 single plane, 26 biplane). For diagnostic procedures, biplane angiography was associated with higher operator dose (38␮Sv (26-50) vs 26␮Sv (23-34), P=0.01). The same observation was not made for PCI procedures: 31␮Sv (20-42) vs 37␮Sv (31-45), P=0.445). Operator dose was poorly correlated with patient dose (r=0.38) and fluoro time (r=0.24). Contrast volume was lower when biplane angiography was utilised during PCI procedures: 122cc (83175) vs 170cc (120-208), P=0.02, and diagnostic procedures: 85cc (51-123) vs 87cc (70-100), P=0.057. Biplane angiography should be used to limit contrast volume for patients at risk of contrast-induced nephropathy. However, this series suggests that the operator radiation dose is higher when biplane imaging is used. Its use should

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therefore be discouraged for patients at low risk of contrastinduced nephropathy. http://dx.doi.org/10.1016/j.hlc.2015.06.409 409 Optical coherence tomography findings in definite stent thrombosis Chan 1,2,∗ ,

J. Raffel 1

M.

Savage 1 ,

K.

Poon 1 ,

C.

1 The

Prince Charles Hospital, Chermside, QLD, Australia 2 University of Queensland, Brisbane, QLD, Australia Introduction: Stent thrombosis (ST) is a rare complication of intracoronary stenting but is associated with high morbidity and mortality. Identifying the underlying cause is imperative to prevent recurrence. We examined the optical coherence tomography (OCT) characteristics of stent thrombosis. Methods: Patients with definite ST (Academic Research Consortium definition) were identified from our prospective OCT registry. The clinical, procedural, and OCT characteristics were analysed. Results: 17 patients with ST were imaged with OCT. A clear aetiology for ST was identified in 13 (77%) patients. Stent undersizing(4 cases), stent malapposition(4 cases), neoatherosclerosis with plaque disruption(4 cases of which 2 also had concomitant restenosis), and poor strut neointimal coverage(3 cases) were found on OCT analysis. Angiography was not able to identify the cause of ST in any of the cases. 14(82%) patients were compliant with dual anti-platelet therapy at the time of ST. There was no relationship between anti-platelet compliance and ST mechanism. 7 patients had bare metal stents(BMS) and 10 had drug-eluting stents(DES). Neoatherosclerosis-related ST presented as very-late ST while mechanical stent related ST occurred at all time points. Conclusion: The high resolution of OCT enabled clear and accurate delineation of the causes of ST, which could not be identified angiographically. In addition to guiding treatment, OCT adds to our understanding of the mechanism of ST. This makes it an important modality to evaluate and treat stent thrombosis both in clinical practice and in research. http://dx.doi.org/10.1016/j.hlc.2015.06.410

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410 Oral anticoagulants in a trauma setting: Cerebral haemorrhage and delayed presentation reversal guidelines: “Time is brain” J. England 1,∗ , L. Davis 2 1 Blue

Mountains District Anzac Memorial Hospital, Katoomba, NSW, Australia 2 Westmead Private Hospital, Westmead, NSW, Australia With the frequent diagnosis of atrial fibrillation, a larger percentage of the population are taking warfarin or new, novel anticoagulants (NOACs dabigatran, apixaban or rivaroxaban). With a traumatic death on warfarin in a 40year-old male (alcohol associated). The coroner asks if the outcome would have been different if he was taking a NOAC. The absolute risk of major bleeding with warfarin is 0.5% to 1.0% per year and is greatest in the early months of therapy, irrespective of head trauma and skull fractures. The NOACs have been shown to have less spontaneous cerebral haemorrhage compared to warfarin; trauma negates all comparisons. However, warfarin therapy can be reversed with intravenous infusions of vitamin K and fresh frozen plasma. There is currently no therapy to reverse the action of the new oral anticoagulants, short of renal dialysis to reverse the X(a) inhibition blood thinning. All patients with a warfarin-related intracerebral haemorrhage and an elevated international normalised ratio (>1.2) should have rapid reversal of the coagulopathy: • Cease warfarin; • Give 5-10mg vitamin K intravenously (6-24 hours to be effective); • Prothrombin complex concentrate 25-50IU/kg intravenously; or • Fresh frozen plasma (150-300mL) intravenously; • Risk of cerebral trauma/violent misadventure should be considered when assessing suitability for potent oral anticoagulants. The coroner adopted the legal precedent of the “eggshell skull” rule. Liability for manslaughter results from wrongful contact and is not excused by the treating doctors’ warfarin prescription. http://dx.doi.org/10.1016/j.hlc.2015.06.411 411 Out-of-hospital cardiac arrest: variations in clinical decision making for immediate coronary angiography H. Han ∗ , E. Jones, O. Farouque Austin Health, VIC, Australia

Background: Resuscitated out-of-hospital cardiac arrest (OHCA) is a common clinical scenario. There is debate regarding the value of immediate coronary angiography (CA) in this setting. The aim of this study was to determine whether