Effects of stent postdilatation during primary PCI for STEMI: Insights from coronary physiology and optical coherence tomography.

OBJECTIVES: This study aimed to assess the impact of stent optimization by NC-balloon postdilatation (PD) during primary-PCI for STEMI with the use of coronary physiology and intracoronary imaging. METHODS: This was a prospective observational study (ClinicalTrials.gov:NCT02788396). Optical coherence tomography (OCT) and physiological measurements were performed immediately before and after PD with the operators blinded to all measurements. The index of microcirculatory resistance (IMR), coronary flow reserve (CFR) and fractional flow reserve (FFR) were measured. OCT analysis was performed for assessment of stent expansion, malapposition, in-stent plaque-thrombus prolapse (PTP) and stent-edge dissections (SED). The change in IMR before and after PD as a measure of microvascular injury was the primary objective of the study. RESULTS: Thirty-two STEMI patients undergoing primary-PCI had physiological measurements before and after PD. All patients received second-generation DES (diameter 3.1 ± 0.5 mm, length 29.9 ± 10.7 mm) and postdilatation with NC-balloons (diameter 3.6 ± 0.6 mm, inflation pressure 19.3 ± 2.0 atm). IMR (44.9 ± 25.6 vs. 48.8 ± 34.2, p = 0.26) and CFR (1.60 ± 0.89 vs. 1.58 ± 0.71, p = 0.87) did not change, while FFR increased after PD (0.91 ± 0.08 vs. 0.93 ± 0.06, p = 0.037). At an individual patient level, IMR increased in half of the cases. PD improved significantly absolute and relative stent expansion, reduced malapposition, and increased PTP. There was no difference in clinically relevant SED. CONCLUSION: In this exploratory, hypothesis-generating study, postdilatation during primary-PCI for STEMI improved stent expansion, apposition and post-PCI FFR, without a significant effect on coronary microcirculation overall. Nevertheless, IMR increased in a group of patients and larger studies are warranted to explore predictors of microcirculatory response to postdilatation.

Contemporary management of stent thrombosis: Predictors of mortality and the role of new-generation drug-eluting stents.

OBJECTIVES: We sought to evaluate mortality predictors and the role of new-generation drug-eluting stents (NG-DES) in stent thrombosis (ST) management. BACKGROUND: No data are available regarding the outcome of patients with ST after interventional management that includes exclusively NG-DES. METHODS: Patients with definite ST of DES or BMS who underwent urgent/emergent angiography between 2015 and 2018 at our institution were considered for the study. After excluding patients who achieved TIMI-flow<2 after intervention or received an old-generation stent, 131 patients were included. Management classification was stent or non-stent treatment (medical management, thromboaspiration, balloon-angioplasty). Follow-up was performed to document all-cause death (ACD) and target-lesion-revascularization (TLR) that was used for censorship. RESULTS: Mode of presentation was STEMI in 88% and UA/NSTEMI in 12%. Type of ST was early, late, and very late in 11, 4, and 85%, respectively. Eighty four patients received stent and 47 non-stent treatment. After 926 ± 34 days, 21 ACDs, 7 TLRs and no cases of definite, recurrent ST were observed. Univariate predictors of in-hospital mortality were LVEF and presentation with shock or cardiac arrest. For patients discharged alive, non-stent treatment (HR 4.2, p = .01), TIMI-2 flow (HR 7.4, p = .002) and GFR < 60 mL/min (HR 3.8, p = .01) were independent predictors of ACD. The stent-treatment group had significantly better ACD-free survival after discharge, both unadjusted (p = .022) and adjusted (p = .018). CONCLUSIONS: After ST management, different predictors were observed for in-hospital mortality and mortality in patients discharged alive. The better outcome with NG-DES treatment is a novel observation, warranting further studies to elucidate if it is associated with stent-related or patient-related factors.

The Effect of Hydrostatic Pressure on Coronary Flow and Pressure-Based Indices of Coronary Stenosis Severity.

Background: To assess whether hydrostatic pressure gradients caused by coronary height differences in supine versus prone positioning during invasive physiological stenosis assessment affect resting and hyperaemic pressure-based indices or coronary flow. Methods: Twenty-three coronary stenoses were assessed in twenty-one patients with stable coronary artery disease. All patients had a stenosis of at least 50% visually defined on previous coronary angiography. Pd/Pa, iFR, FFR, and coronary flow velocity (APV) measured using a Doppler were recorded across the same stenosis, with the patient in the prone position, followed by repeat measurements in the standard supine position. Results: When comparing prone to supine measurements in the same stenosis, in the LAD, there was a significant change in mean Pd/Pa of 0.08 ± 0.04 (p = 0.0006), in the iFR of 0.06 ± 0.07 (p = 0.02), and in the FFR of 0.09 ± 0.07 (p = 0.003). In the Cx, there was a change in mean Pd/Pa of 0.05 ± 0.04 (p = 0.009), iFR of 0.07 ± 0.04 (p = 0.01), and FFR of 0.05 ± 0.03 (p = 0.006). In the RCA, there was a change in Pd/Pa of 0.05 ± 0.04 (p = 0.032), iFR of 0.04 ± 0.05 (p = 0.19), and FFR of 0.04+-0.03 (p = 0.004). Resting and hyperaemic coronary flow did not change significantly (resting delta APV = 1.6 cm/s, p = 0.31; hyperaemic delta APV = 0.9 cm/s, p = 0.85). Finally, 36% of iFR measurements and 26% of FFR measurements were re-classified across an ischaemic threshold when prone and supine measurements were compared across the same stenosis. Conclusions: Pd/Pa, iFR, and FFR were affected by hydrostatic pressure variations caused by coronary height differences in prone versus supine positioning. Coronary flow did not change signifying a purely pressure-based phenomenon.

Clinical Impact of Intracoronary Imaging in the Management of Stent Thrombosis.

Objectives: Use of intracoronary imaging (ICI) in cases of stent thrombosis (ST) is recommended and tailored treatment appears reasonable. Nevertheless, data supporting such a strategy are lacking. The aim of this study was to evaluate the clinical impact of ICI in the management of ST. Methods: The unadjusted study population was consecutive patients with definite ST presenting in a single tertiary cardiac centre and undergoing percutaneous coronary intervention (PCI). The presumed major mechanism of ST was assigned according to the real-time ICI interpretation by the PCI operator. Propensity score matching was performed with regard to ICI use to form the adjusted population and Kaplan-Meier analysis was applied to compare survival free of cardiac death (CD) or target lesion revascularization (TLR). Results: The unadjusted population included 130 ST patients, with the majority presenting with ST-elevation myocardial infarction (STEMI) (88%) and very late ST (86%). ICI was performed in 45 patients, of whom optical coherence tomography (OCT) was performed in 30 cases. When the individual ST mechanisms were viewed as groups, there was an interaction observed between type of treatment (stent vs. non-stent) and ST mechanism, with non-stent treatment being more prevalent in cases of underexpansion, malapposition, in-stent restenosis and mechanism uncertainty. After application of matching, two groups of 30 patients were formed. ICI-guided management resulted in better survival free of CD-TLR at 2 years (93% vs. 73%, p = 0.037). Conclusions: Intracoronary imaging guidance during PCI for ST had a direct impact on management (stent vs. non-stent) and resulted in a lower event rate at mid-term follow-up when propensity matched analysis was applied.

Comparison of bolus versus continuous thermodilution derived indices of microvascular dysfunction in revascularized coronary syndromes.

Background: The assessment of coronary microvascular dysfunction (CMD) using invasive methods is a field of growing interest, however the preferred method remains debated. Bolus and continuous thermodilution are commonly used methods, but weak agreement has been observed in patients with angina with non-obstructive coronary arteries (ANOCA). This study examined their agreement in revascularized acute coronary syndromes (ACS) and chronic coronary syndromes (CCS) patients. Objective: To compare bolus thermodilution and continuous thermodilution indices of CMD in revascularized ACS and CCS patients and assess their diagnostic agreement at pre-defined cut-off points. Methods: Patients from two centers underwent paired bolus and continuous thermodilution assessments after revascularization. CMD indices were compared between the two methods and their agreements at binary cut-off points were assessed. Results: Ninety-six patients and 116 vessels were included. The mean age was 64 ± 11 years, and 20 (21 %) were female. Overall, weak correlations were observed between the Index of Microcirculatory Resistance (IMR) and continuous thermodilution microvascular resistance (Rµ) (rho = 0.30p = 0.001). The median coronary flow reserve (CFR) from continuous thermodilution (CFRcont) and bolus thermodilution (CFRbolus) were 2.19 (1.76-2.67) and 2.55 (1.50-3.58), respectively (p < 0.001). Weak correlation and agreement were observed between CFRcont and CFRbolus (rho = 0.37, p < 0.001, ICC 0.228 [0.055-0.389]). When assessed at CFR cut-off values of 2.0 and 2.5, the methods disagreed in 41 (35 %) and 45 (39 %) of cases, respectively. Conclusions: There is a significant difference and weak agreement between bolus and continuous thermodilution-derived indices, which must be considered when diagnosing CMD in ACS and CCS patients.

Feasibility of early waking cardiac arrest patients whilst receiving therapeutic hypothermia: The therapeutic hypothermia and early waking (THAW) trial.

AIM: To determine the safety and feasibility of an early (12 h) waking and extubation protocol for out-of-hospital cardiac arrest (OHCA) patients receiving targeted temperature management (TTM). METHODS: This was a single-centre, prospective, non-randomised, observational, safety and feasibility pilot study which included successfully resuscitated OHCA patients, of presumed cardiac cause. Inclusion criteria were: OHCA patients aged over 18 years with a return of spontaneous circulation, who were going to receive TTM33 (TTM at 33 °C for 24 h and prevention of hyperthermia for 72 h) as part of their post cardiac arrest care. Clinical stability was measured against physiological and neurological parameters as well as clinical assessment. RESULTS: 50 consecutive patients were included (median age 65.5 years, 82% male) in the study. Four (8%) patients died within the first twelve hours and were excluded from the final cohort (n = 46). Twenty-three patients (46%) were considered clinically stable and suitable for early waking based on the intention to treat analysis; 12 patients were extubated early based on a variety of clinical factors (21.4 ± 8.6 h) whilst continuing to receive TTM33 with a mean core temperature of 34.2 °C when extubated. Of these, five patients were discharged from the intensive care unit (ICU) <48 h after admission with a mean ICU length of stay 1.8 ± 0.4 days. Twenty-eight patients (56%) were discharged from the ICU with a modified Rankin Score of 0-2. The overall intra-hospital mortality was 50% (n = 25). CONCLUSIONS: It is safe and feasible to wake selected comatose OHCA patients at 12 h, allowing for earlier positive neuro-prognostication and reduced ICU stay.

Coronary artery height differences and their effect on fractional flow reserve.

BACKGROUND: Fractional flow reserve (FFR) uses pressure-based measurements to assess the severity of a coronary stenosis. Distal pressure (Pd) is often at a different vertical height to that of the proximal aortic pressure (Pa). The difference in pressure between Pd and Pa due to hydrostatic pressure, may impact FFR calculation. METHODS: One hundred computed tomography coronary angiographies were used to measure height differences between the coronary ostia and points in the coronary tree. Mean heights were used to calculate the hydrostatic pressure effect in each artery, using a correction factor of 0.8 mmHg/cm. This was tested in a simulation of intermediate coronary stenosis to give the "corrected FFR" (cFFR) and percentage of values, which crossed a threshold of 0.8. RESULTS: The mean height from coronary ostium to distal left anterior descending (LAD) was +5.26 cm, distal circumflex (Cx) -3.35 cm, distal right coronary artery-posterior left ventricular artery (RCA-PLV) -5.74 cm and distal RCA-posterior descending artery (PDA) +1.83 cm. For LAD, correction resulted in a mean change in FFR of +0.042, -0.027 in the Cx, -0.046 in the PLV and +0.015 in the PDA. Using 200 random FFR values between 0.75 and 0.85, the resulting cFFR crossed the clinical treatment threshold of 0.8 in 43% of LAD, 27% of Cx, 47% of PLV and 15% of PDA cases. CONCLUSIONS: There are significant vertical height differences between the distal artery (Pd) and its point of normalization (Pa). This is likely to have a modest effect on FFR, and correcting for this results in a proportion of values crossing treatment thresholds. Operators should be mindful of this phenomenon when interpreting FFR values.

CASTLE score versus J-CTO score for the prediction of technical success in chronic total occlusion percutaneous revascularisation.

AIMS: We sought to compare the efficiency of the novel EuroCTO (CASTLE) score with the commonly used Multicentre CTO Registry in Japan (J-CTO) score in predicting procedural success of percutaneous coronary intervention (PCI) for coronary chronic total occlusions (CTOs). METHODS AND RESULTS: We evaluated 660 consecutive CTO PCIs (mean age 66±11 years, 84% male). The mean J-CTO and EuroCTO (CASTLE) scores were 1.86±1.2 and 1.74±1.2, respectively. Antegrade wire escalation, antegrade dissection re-entry and retrograde approach were used in 82%, 14% and 37% of cases, respectively. Receiver operating characteristic analysis demonstrated equal overall discriminatory capacity between the two scores (AUC 0.698, 95% CI: 0.653-0.742, p<0.001 for J-CTO vs AUC 0.676, 95% CI: 0.627-0.725, p<0.001 for EuroCTO; AUC difference: 0.022, p=0.5). However, for more complex procedures (J-CTO ≥3 or EuroCTO [CASTLE] ≥4]), the predictive capacity of the EuroCTO (CASTLE) score appeared superior (AUC 0.588, 95% CI: 0.509-0.668, p=0.03 for EuroCTO [CASTLE] score vs AUC 0.473, 95% CI: 0.393-0.553, p=NS for the J-CTO score, AUC difference: 0.115, p=0.04). CONCLUSIONS: In this study, the novel EuroCTO (CASTLE) score was comparable to the J-CTO score in predicting CTO PCI outcome with a superior discriminatory capacity for the more complex cases.

Impact of right atrial pressure on fractional flow reserve calculation in the presence of a chronic total occlusion.

BACKGROUND: The aim of this study was to assess the impact of right atrial pressure (Pra) on non-CTO vessels FFR measurements in patients with a chronic total occlusion. METHODS: Consecutive patients who underwent PCI for a CTO of the right coronary artery (RCA) were included. Prior to RCA recanalization, FFR and FFRmyo were measured in non-CTO vessels. FFR was calculated using the Pd/Pa equation during maximum hyperaemia and also accounting for right atrial pressure (Pd-Pra/Pa-Pra). Non-CTO vessels were characterised as major or minor donors based on angiographic assessment of provided collaterals. RESULTS: FFR and FFRmyo were measured in 68 arteries (34 LAD and 34 Cx) in 34 consecutive patients with successful RCA CTO PCI. Patients' mean age was 62 ±â€¯10 years old and 88% were male. Mean left ventricular ejection fraction was 51% ±â€¯20. During maximum hyperaemia, mean Pra, Pa, and Pd were 4.1 ±â€¯3.8 mm Hg, 82.6 ±â€¯12.2 mm Hg, and 63.8 ±â€¯14.3 mm Hg, respectively. In the major donor vessel, FFRmyo showed a difference of 0.007 to FFR (0.760 ±â€¯0.113 vs. 0.767 ±â€¯0.112, p = 0.004). In the minor donor vessel the difference was 0.004 (0.895 ±â€¯0.067 vs. 0.899 ±â€¯0.065, p < 0.001). There was a strong positive correlation between the FFR and FFRmyo in both the major and minor donor vessel groups (r = 0.993, p < 0.001 and r = 0.996, p < 0.001 respectively). CONCLUSION: In the presence of a CTO, RA pressure adjustment of FFR in the non-CTO vessels leads to trivial numerical changes, which are statistically significant but clinically negligible.

Serial Fractional Flow Reserve Measurements Post Coronary Chronic Total Occlusion Percutaneous Coronary Intervention.

Background The aim of this study was to evaluate the functional result of chronic total occlusion percutaneous coronary intervention (PCI) measured by fractional flow reserve (FFR) immediately post the index procedure and at short-term follow-up. Methods and Results This was a prospective single-center observational study. Consecutive patients with right coronary artery chronic total occlusion scheduled for elective PCI were included. FFR measurements were performed immediately after successful PCI and at 4 months follow-up. Twenty-six patients completed baseline and follow-up measurements. Mean age was 61.2±9.7 years, 88.5% of the patients were male, and 19.2% were diabetic. The mean FFR immediately after successful chronic total occlusion PCI was 0.82±0.10 and significantly increased to 0.89±0.07 at 4 months ( P<0.001). The FFR increased in 77% of the patients with a mean absolute increase of 0.07±0.08. The incidence of FFR ≤0.80 immediately after PCI was significantly higher amongst patients with subintimal versus intraplaque recanalization (23% versus 12%; P=0.03). At 4 months, FFR ≤0.80 was found only in 2 patients with subintimal recanalization. At follow-up, 42.7% of the patients continued to have an FFR <0.90. Conclusions Post chronic total occlusion PCI, FFR increased significantly at short-term follow-up compared with measurements post index procedure. Because FFR remained <0.90 in many cases, further efforts should be made to optimize procedural results.

Is It Feasible and Safe to Wake Cardiac Arrest Patients Receiving Mild Therapeutic Hypothermia After 12 Hours to Enable Early Neuro-Prognostication? The Therapeutic Hypothermia and Early Waking Trial Protocol.

Mild therapeutic hypothermia (MTH 33°C) post out-of-hospital cardiac arrest (OHCA) is widely accepted as standard of care. However, uncertainty remains around the dose and therapy duration. OHCA patients are usually kept sedated±paralyzed and ventilated for the first 24-36 hours, which allows for targeted temperature management, but makes neurological prognostication challenging. The aim of this study is to investigate the feasibility and safety of assessing the unconscious OHCA patient after 12 hours for early waking/extubation while continuing to provide MTH for 24 hours, and fever prevention for 72 hours by using an intravenous temperature management (IVTM) system and established conscious MTH anti-shiver regimens. This is a single-center, prospective, non-randomized observational study that will compare the results of early awakening (at 12 hours) with historical controls. A total of 50 consecutive unconscious survivors of OHCA, treated with MTH, who meet the Therapeutic Hypothermia and eArly Waking (THAW) inclusion criteria will be enrolled. The patient will receive MTH by using IVTM. After 12 hours of MTH, patients will be assessed by using strict clinical criteria to determine suitability for early waking and extubation. Once awake and extubated, MTH will continue for 24 hours with skin counter-warming and anti-shiver regimen followed fever prevention up to 72 hours. All patients will have serial electroencephalogram (EEG), somatic sensory potential, and neuro-biomarkers performed on admission to intensive care unit, 6 and 12 hours, then every 24 hours until 72 hours. The study has been approved by the National Research Ethics Service, Health Research Authority.

Impact of point-of-care pre-procedure creatinine and eGFR testing in patients with ST segment elevation myocardial infarction undergoing primary PCI: The pilot STATCREAT study.

BACKGROUND: Contrast-induced acute kidney injury (CI-AKI) is a recognised complication during primary PCI that affects short and long term prognosis. The aim of this study was to assess the impact of point-of-care (POC) pre-PPCI creatinine and eGFR testing in STEMI patients. METHODS: 160 STEMI patients (STATCREAT group) with pre-procedure POC testing of Cr and eGFR were compared with 294 consecutive retrospective STEMI patients (control group). Patients were further divided into subjects with or without pre-existing CKD. RESULTS: The incidence of CI-AKI in the whole population was 14.5% and not different between the two overall groups. For patients with pre-procedure CKD, contrast dose was significantly reduced in the STATCREAT group (124.6ml vs. 152.3ml, p=0.015). The incidence of CI-AKI was 5.9% (n=2) in the STATCREAT group compared with 17.9% (n=10) in the control group (p=0.12). There was no difference in the number of lesions treated (1.118 vs. 1.196, p=0.643) or stents used (1.176 vs. 1.250, p=0.78). For non-CKD patients, there was no significant difference in contrast dose (172.4ml vs. 158.4ml, p=0.067), CI-AKI incidence (16.7% vs. 13.4%, p=0.4), treated lesions (1.167 vs. 1.164, p=1.0) or stents used (1.214 vs. 1.168, p=0.611) between the two groups. CONCLUSIONS: Pre-PPCI point-of-care renal function testing did not reduce the incidence of CI-AKI in the overall group of STEMI patients. In patients with CKD, contrast dose was significantly reduced, but a numerical reduction in CI-AKI was not found to be statistically significant. No significant differences were found in the non-CKD group.

Myocardial beta-adrenoceptor density one month after acute myocardial infarction predicts left ventricular volumes at six months.

OBJECTIVE: To investigate whether myocardial beta-adrenoceptor (beta-AR) downregulation precedes and predicts left ventricular (LV) dilation after acute myocardial infarction (AMI), we measured beta-AR density within four weeks of AMI and correlated it with serial measurements of LV volumes. BACKGROUND: Patients who develop heart failure following AMI have an increased sympathetic drive to the heart within the first four weeks after infarction. METHODS: We prospectively studied 61 patients in whom AMI was the first presentation of coronary artery disease (CAD) and with no signs of heart failure. The LV volumes were measured one, three, and six months after AMI by echocardiography. Beta-AR density was measured using positron emission tomography with S-[(11)C]CGP 12177. Seventeen matched healthy volunteers served as controls. RESULTS: Whole heart beta-AR density was lower in patients than in controls (6.25 +/- 0.98 pmol/g vs. 8.32 +/- 2.14 pmol/g, p < 0.0001). In patients, beta-AR density was inversely correlated with end-systolic and end-diastolic volumes six months after AMI. Patients whose LV was dilated at six months had a lower beta-AR density in noninfarcted myocardium than patients without dilation (6.15 pmol/g vs. 6.98 pmol/g, p = 0.008). In addition, beta-AR density in noninfarcted myocardium was higher when the infarct-related artery was patent (6.87 +/- 1.14 pmol/g vs. 5.76 +/- 0.86 pmol/g occluded, p < 0.01). CONCLUSIONS: Myocardial beta-AR density is reduced after AMI in the absence of heart failure, and the reduction predicts later LV dilation. These data are suggestive of an enhanced sympathetic drive to the heart, having an important etiologic role in LV remodeling after AMI.

Assessment of the long-term reproducibility of baseline and dobutamine-induced myocardial blood flow in patients with stable coronary artery disease.

UNLABELLED: Although physical exercise is the preferred stimulus for cardiac stress testing, pharmacologic agents are useful in patients who are unable to exercise. Previous studies have demonstrated short-term repeatability of exercise and adenosine stress, but little data exist regarding dobutamine (Dob) stress or the long-term reproducibility of pharmacologic stressors in coronary artery disease (CAD) patients. PET allows accurate, noninvasive quantification of myocardial blood flow (MBF) and coronary flow reserve (CFR). The aim of the study was to investigate the long-term reproducibility of Dob stress on MBF and CFR in CAD patients using PET. METHODS: Fifteen patients with chronic stable angina and angiographically proven CAD (>70% stenosis in at least 1 major coronary artery) underwent PET with (15)O-labeled water and Dob stress at baseline (time [t] = 0) and after 24 wk (t = 24). MBF at rest and MBF during Dob stress were calculated for the whole left ventricle, the region subtended by the most severe coronary artery stenosis (Isc), and remote myocardium subtended by arteries with minimal or no disease (Rem). Reproducibility was assessed using the Bland-Altman (BA) repeatability coefficient and was also expressed as a percentage of the mean value of the 2 measurements (%BA). RESULTS: Dob dose (30 +/- 11 vs. 031 +/- 11 microg/kg/min; P = not significant [ns]) and peak Dob rate.pressure product (20,738 +/- 3,947 vs. 20,047 +/- 3,455 mm Hg x beats/min; P = ns) were comparable at t = 0 and t = 24. There was no significant difference in resting or Dob MBF (mL/min/g) between t = 0 and t = 24 for the whole left ventricle (1.03 +/- 0.19 vs. 1.10 +/- 0.20 and 2.02 +/- 0.44 vs. 2.09 +/- 0.57; P = ns for both), Isc (1.05 +/- 0.24 vs. 1.10 +/- 0.26 and 1.79 +/- 0.53 vs. 1.84 +/- 0.62; P = ns for both), or Rem (1.03 +/- 0.23 vs. 1.10 +/- 0.26 and 2.27 +/- 0.63 vs. 2.26 +/- 0.63; P = ns for both) territories. Global (1.98 +/- 0.40 vs. 1.90 +/- 0.46; P = ns) and regional CFR (Isc: 1.65 +/- 0.40 vs. 1.67 +/- 0.47, and Rem: 2.25 +/- 0.57 vs. 2.06 +/- 0.51; P = ns) were reproducible. The BA repeatability coefficients (and %BA) for MBF in ischemic and remote territories were 0.3 (28%) and 0.26 (24%) at rest and 0.49 (27%) and 0.58 (26%) during Dob stress. CONCLUSION: In patients with clinically stable CAD, Dob induces reproducible changes in both global and regional MBF and CFR over a time interval of 24 wk. The reproducibility of MBF and CFR with Dob was comparable with the short-term repeatability reported for adenosine and physical exercise in healthy subjects.

Comparison of clinical characteristics and outcomes in patients with left bundle branch block versus ST-elevation myocardial infarction referred for primary percutaneous coronary intervention.

AIMS: Recent studies have suggested that a low proportion of patients presenting with left bundle branch block (LBBB) require emergency intervention. In this study, we have compared baseline clinical characteristics, angiographic findings and subsequent outcomes in patients with LBBB versus ST-elevation myocardial infarction (STEMI) referred to our tertiary centre for primary percutaneous coronary intervention (PCI). METHODS AND RESULTS: A large retrospective observational study was performed involving 1875 consecutive patients presenting to our single tertiary cardiac centre for primary PCI over a 27-month period. Patients presenting with LBBB (n=155, 8.3%) were significantly older (P<0.0001) and were more likely to be female (P<0.0001) and have a prior history of myocardial infarction (P<0.0001) or coronary artery bypass graft surgery (P=0.005). Rates of acute occlusion (12.2 vs. 63%; P<0.0001) and PCI (26 vs. 83%; P<0.0001) were significantly lower in LBBB patients compared with STEMI patients. Although the 30-day mortality was similar, overall mortality during the 2 years of follow-up was significantly higher in the LBBB group compared with the STEMI group (27.8 vs. 13.9%; P=0.023). CONCLUSION: The incidence of an acutely occluded vessel is low in LBBB when compared with STEMI, but the long-term outcome is significantly worse. Patients with LBBB referred for primary PCI need better risk stratification, and further work is needed to identify potential diagnostic and management strategies.

Early targeted brain COOLing in the cardiac CATHeterisation laboratory following cardiac arrest (COOLCATH).

INTRODUCTION: Trials demonstrate significant clinical benefit in patients receiving therapeutic hypothermia (TH) after cardiac arrest. However, incidence of mortality and morbidity remains high in this patient group. Rapid targeted brain hypothermia induction, together with prompt correction of the underlying cause may improve outcomes in these patients. This study investigates the efficacy of Rhinochill, an intranasal cooling device over Blanketrol, a surface cooling device in inducing TH in cardiac arrest patients within the cardiac catheter laboratory. METHODS: 70 patients were randomized to TH induction with either Rhinochill or Blanketrol. Primary outcome measures were time to reach tympanic ≤34 °C from randomisation as a surrogate for brain temperature and oesophageal ≤34 °C from randomisation as a measurement of core body temperature. Secondary outcomes included first hour temperature drop, length of stay in intensive care unit, hospital stay, neurological recovery and all-cause mortality at hospital discharge. RESULTS: There was no difference in time to reach ≤34 °C between Rhinochill and Blanketrol (Tympanic ≤34 °C, 75 vs. 107 mins; p=0.101; Oesophageal ≤34 °C, 85 vs. 115 mins; p=0.151). Tympanic temperature dropped significantly with Rhinochill in the first hour (1.75 vs. 0.94 °C; p<0.001). No difference was detected in any other secondary outcome measures. Catheter laboratory-based TH induction resulted in a survival to hospital discharge of 67.1%. CONCLUSION: In this study, Rhinochill was not found to be more efficient than Blanketrol for TH induction, although there was a non-significant trend in favour of Rhinochill that potentially warrants further investigation with a larger trial.