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Results:

CABG NO CABG p-Value

Baseline dataAge (years) 69.9 ± 10.2 65.8 ± 13.3 <.0001Males (%) 76 75 <.0001MI (%) 64.8 29.5 <.0001Angina (%) 86.5 46.8 <.0001CHF (%) 19.1 10.2 <.0001DM (%) 31.6 23.6 <.0001Renal Disease (%) 13.5 7.0 <.0001

DiagnosisMean GRACE risk

score + SD126.3 ± 33.1 127.2 ± 37.9 0.4

STEMI (%) 8.0 30.6 <.0001NSTEMI (%) 30.5 33.1UA (%) 44.6 24.6Angiography (%) 49.2 63.5 <.0001

Conclusions: Although there were differences betweenthe CABG and no CABG groups, the CABG groupunexpectedly had a lower rate of coronary angiographycompared with no CABG. This difference persisted evenafter adjustment for age, gender and diagnosis at presen-tation (odds ratio = 0.64 (CI 0.54–0.75).

doi:10.1016/j.hlc.2009.05.543

498MAJOR STENT DEFORMATION/PSEUDO FRACTUREOF 7 CROWN ENDEAVOR STENT: INCIDENCE ANDCAUSATIVE FACTORS

M.R. Pitney 1,2,, K.J. Pitney 3, N. Jepson 1,2, D.

Friedman 1,2, N. Dang 1, J. Matthews 1,2, R. Giles 1,2

1 Eastern Heart Clinic, Sydney Australia2 Prince of Wales Hospital, Sydney, Australia3 University of NSW, Sydney, Australia

Introduction: This is the initial report of a unique com-plication of the 7 crown Endeavor stent (2.25–2.75 mm)whereby the post-dilation balloon catches and causesmajor stent deformation angiographically appearing as alarge stent fracture (see figure). We sought to determinefrequency and cause. The 7 crown stent has a single helixsupporting backbone which improves flexibility but limitslongitudinal strength.

Methods: A retrospective analysis of all 7 crownEndeavor stents deployed at our institution. Bench testingwas also performed by deploying and post-dilating stentsin 2.5 mm tubing at a 50 mm diameter constant curve, thenimaging with IVUS and optical scanning.

Results: There were 7 cases of major stent deforma-tion/pseudo fracture representing an incidence of 1.0% (7/701), or 1.2% of stents that were post-dilated (7/575). Proce-dural variables increasing risk include tortuosity and theuse of stiffer wires. In benchtop testing, balloon “catch”was reproducible at a frequency of 10–50% depending ontechnique. Factors increasing frequency included subop-timal stent deployment, stiffer wires, and slower speed ofballoon advancement. Under worst case conditions (tip ofthe post-dilatation balloon came in contact with the stentopposite its supporting helix) balloon catch resulted insignificant stent deformation 10% of the time. The compli-cation could not be replicated with 9 crown stents (doublehelix weld pattern).

Conclusion: When post-dilation is performed, majorstent disruption/pseudo fracture occurs with the 7 crownEndeavor in 1.2% of cases. Operators need to be aware ofthe complication and develop strategies to deal with it.

doi:10.1016/j.hlc.2009.05.544

499MANAGEMENT AND OUTCOMES OF EARLY STENTTHROMBOSIS

Rohan Gupta 1, Patrick Diu 2, Saissan Rajendran 1, MariaGonzalez 2, Andrew Hopkins 1,2, John French 1,2, CraigJuergens 1,2

1 University of New South Wales, Sydney, NSW, Australia2 Liverpool Hospital, Sydney, NSW, Australia

Background: Patients who have stent thrombosis may beconsidered at higher risk of recurrent episodes, howeverthe amount of risk requires clarification.

Methods: To determine the management and outcomesof patients after their first episode of early stent thrombosis(0–30 days), we retrospectively analysed 45 patients whohad an episode of early stent thrombosis (ST) at Liverpoolhospital over the period 1998–2008 and underwent repeatpercutaneous coronary intervention (PCI) as manage-ment. We evaluated procedural details, use of anti-plateletand anti-thrombotic therapy, and post-procedural man-agement. Patients were followed, for a median of 5.3 years,to assess the incidence of recurrent ST and MACE (com-posite of non-fatal myocardial infarction, coronary arterybypass grafting and cardiac death) after their second pro-cedure.

Results: The median time for ST after first PCI was 6 days(IQR 3–11 days); 34 presented with STEMI, 6 NSTEMI and5 UA. 39 patients (87%) were administered glycoproteinIIb/IIIa inhibitors (GPI). 37 patients were restented and 8received balloon angioplasty alone. 13 patients (29%) hada recurrent ST; 5 received a third PCI; 5 underwent CABG;and 3 treated medically. Of the 5 undergoing a third PCI,2 had another ST requiring CABG. After the second pro-cedure there were 32 MACEs (7 deaths (16%); 17 non-fatalMIs (38%); 9 CABGs (20%)); 10 patients had more than 1event.

Conclusion: ST is largely managed by restenting of thetarget vessel and GPIs. ST is associated with a high degree

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of morbidity and mortality and there are high rates ofrecurrent episodes.

doi:10.1016/j.hlc.2009.05.545

500MEASUREMENT OF THE INDEX OF MICRO-CIRCULATORY RESISTANCE PREDICTSPERI-PERCUTANEOUS CORONARY INTERVENTIONMYOCARDIAL INFARCTION

A.S.C. Yong 1,2,, C. Chawantanpipat 1, M.K.C. Ng 1

1 Cardiology Department, Royal Prince Alfred Hospital,Sydney, Australia2 Cardiology Department, Concord Repatriation General Hos-pital, Sydney, Australia

Background: The index of microcirculatory resis-tance (IMR) is an invasive pressure–temperature sensorwire derived measurement, performed during cardiaccatheterization that provides a specific quantitativeassessment of coronary microvasculature status. We haverecently shown that IMR predicts infarct size in the pri-mary percutaneous coronary intervention (PCI) setting.We now investigate the use of IMR in predicting peri-PCImyocardial infarction (PMI).

Methods: N = 14 consecutive patients undergoing elec-tive PCI of a single lesion were recruited. Thepressure–temperature sensor wire (RADI, Uppsala) wasused for PCI and physiological measurements. Mea-surements obtained included mean transit time at rest(TmnR), hyperemic Tmn (TmnH), hyperemic proxi-mal pressure (Pa), hyperemic distal pressure (Pd) andwedge pressure (Pw). Hyperemia was induced by adeno-sine infusion (140 mcg/kg/min). Coronary flow reserve(CFR = TmnR/TmnH) and IMR corrected for collateralflow (PaXTmnHX[Pd − Pw]/[Pa − Pw]) were calculated preand post-PCI. Troponin T levels were measured before and1 day post-PCI. PMI was defined as post-procedural tro-ponin T >0.03 �g/L or a post-procedural rise in patientswith downward trending pre-PCI troponin levels.

Results: All patients had normal or downward trend-ing pre-PCI troponin T levels. Three (21.4%) patientshad a PMI. Mean ± SD of procedural IMR change was5.5 ± 14. Using an IMR rise of >5 as a cut-off, IMR elevationcould predict PMI (sensitivity = 100%, specificity = 73%,area under ROC curve = 0.90). CFR was not predictive ofPMI.

Conclusions: Peri-procedural IMR elevation is predic-tive of PMI. IMR is easily assessed and provides an early,on-table detection method for PMI. Such a method facili-tates the development of therapeutic strategies and couldhelp in post-procedural management decisions.

doi:10.1016/j.hlc.2009.05.546

501MYOCARDIAL INJURY FOLLOWING CORONARYARTERY SURGERY VERSUS ANGIOPLASTY(MICASA): A RANDOMIZED TRIAL USINGBIOCHEMICAL MARKERS AND MAGNETICRESONANCE IMAGING

William van Gaal 1,2,3,, Jayanth Arnold 3, Luca Testa 3,Theo Karamitsos 3, Chris Lim 3, Francis Ponnuthurai 1,3,Joseph Selvanayagem 3, Steve Westaby 3, StefanNeubauer 3, Adrian Banning 3

1 Northern Health, Epping, Australia2 University of Melbourne, Melbourne, Australia3 John Radcliffe Hospital, Oxford, UK

Background: The frequency of peri-procedural myocar-dial injury defined by late gadolinium enhancementon magnetic resonance imaging (MRI) following per-cutaneous coronary intervention (PCI) and coronaryartery bypass grafting (CABG) have not been directlycompared. Furthermore, peri-procedural necrosis andmyocardial infarction (MI) were recently redefined by theESC/AHA/WHF. We sought to compare the frequencyof Troponin I and MRI defined injury following PCI andCABG.

Methods: Single centre randomized trial. Patients with2 or 3 vessel CAD and/or left main disease were eligible.

Results: Of 80 patients enrolled, 40 underwent PCIand 39 underwent CABG (1 death prior). Two PCI and 7CABG patients had incomplete MRI evaluation (5 claus-trophobia, 3 renal impairment, 1 image quality), and 4CABG patients had incomplete biomarkers. Mean syn-tax scores were 23.6 ± 7.6 vs. 22.1 ± 6.8 (p = 0.34) and meanEuro scores 1.85 vs. 2.31 (p = 0.21) for PCI and CABGrespectively. Following PCI, 6/38 (15.8%) patients had lategadolinium enhancement, compared with 9/32 (28.1%)following CABG (p = 0.25). Using the new universal defini-tions, necrosis occurred in 30/40 (75.0%) PCI patients and35/35 (100%) CABG patients (p = 0.001), and MI occurred in30/40 (75.0%) PCI patients and 9/32 (28.1%) CABG patients(p = 0.0001). Only 6/30 (20.0%) PCI patients who met thenew definition of peri-procedural MI had late enhance-ment on MRI.

Conclusions: The incidence of MRI defined infarctiondid not differ between groups. According to the newdefinition, necrosis was significantly lower following PCIcompared with CABG. The new definition of PCI relatedMI overestimates the incidence MI compared with MRIdefined infarction.

doi:10.1016/j.hlc.2009.05.547