James Hampton-Till

e-ASPECTS software is non-inferior to neuroradiologists in applying the ASPECT score to computed tomography scans of acute ischemic stroke patients.

Background The Alberta Stroke Program Early Computed Tomography Score (ASPECTS) is an established 10-point quantitative topographic computed tomography scan score to assess early ischemic changes. We performed a non-inferiority trial between the e-ASPECTS software and neuroradiologists in scoring ASPECTS on non-contrast enhanced computed tomography images of acute ischemic stroke patients. Methods In this multicenter study, e-ASPECTS and three independent neuroradiologists retrospectively and blindly assessed baseline non-contrast enhanced computed tomography images of 132 patients with acute anterior circulation ischemic stroke. Follow-up scans served as ground truth to determine the definite area of infarction. Sensitivity, specificity, and accuracy for region- and score-based analysis, receiver-operating characteristic curves, Bland-Altman plots and Matthews correlation coefficients relative to the ground truth were calculated and comparisons were made between neuroradiologists and different pre-specified e-ASPECTS operating points. The non-inferiority margin was set to 10% for both sensitivity and specificity on region-based analysis. Results In total 2640 (132 patients × 20 regions per patient) ASPECTS regions were scored. Mean time from onset to baseline computed tomography was 146 ± 124 min and median NIH Stroke Scale (NIHSS) was 11 (6–17, interquartile range). Median ASPECTS for ground truth on follow-up imaging was 8 (6.5–9, interquartile range). In the region-based analysis, two e-ASPECTS operating points (sensitivity, specificity, and accuracy of 44%, 93%, 87% and 44%, 91%, 85%) were statistically non-inferior to all three neuroradiologists (all p-values <0.003). Both Matthews correlation coefficients for e-ASPECTS were higher (0.36 and 0.34) than those of all neuroradiologists (0.32, 0.31, and 0.3). Conclusions e-ASPECTS was non-inferior to three neuroradiologists in scoring ASPECTS on non-contrast enhanced computed tomography images of acute stroke patients.

RV diastolic dysfunction: time to re-evaluate its importance in heart failure

Right ventricular (RV) diastolic dysfunction was first reported as an indicator for the assessment of ventricular dysfunction in heart failure a little over two decades ago. However, the underlying mechanisms and precise role of RV diastolic dysfunction in heart failure remain poorly described. Complexities in the structure and function of the RV make the detailed assessment of the contractile performance challenging when compared to its left ventricular (LV) counterpart. LV dysfunction is known to directly affect patient outcome in heart failure. As such, the focus has therefore been on LV function. Nevertheless, a strategy for the diagnosis and assessment of RV diastolic dysfunction has not been established. Here, we review the different causal mechanisms underlying RV diastolic dysfunction, summarising the current assessment techniques used in a clinical environment. Finally, we explore the role of load-independent indices of RV contractility, derived from the conductance technique, to fully interrogate the RV and expand our knowledge and understanding of RV diastolic dysfunction. Accurate assessment of RV contractility may yield further important prognostic information that will benefit patients with diastolic heart failure.

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.

Ventriculo‐arterial coupling detects occult RV dysfunction in chronic thromboembolic pulmonary vascular disease

Chronic thromboembolic disease (CTED) is suboptimally defined by a mean pulmonary artery pressure (mPAP) <25 mmHg at rest in patients that remain symptomatic from chronic pulmonary artery thrombi. To improve identification of right ventricular (RV) pathology in patients with thromboembolic obstruction, we hypothesized that the RV ventriculo‐arterial (Ees/Ea) coupling ratio at maximal stroke work (Ees/Eamax sw) derived from an animal model of pulmonary obstruction may be used to identify occult RV dysfunction (low Ees/Ea) or residual RV energetic reserve (high Ees/Ea). Eighteen open chested pigs had conductance catheter RV pressure‐volume (PV)‐loops recorded during PA snare to determine Ees/Eamax sw. This was then applied to 10 patients with chronic thromboembolic pulmonary hypertension (CTEPH) and ten patients with CTED, also assessed by RV conductance catheter and cardiopulmonary exercise testing. All patients were then restratified by Ees/Ea. The animal model determined an Ees/Eamax sw = 0.68 ± 0.23 threshold, either side of which cardiac output and RV stroke work fell. Two patients with CTED were identified with an Ees/Ea well below 0.68 suggesting occult RV dysfunction whilst three patients with CTEPH demonstrated Ees/Ea ≥ 0.68 suggesting residual RV energetic reserve. Ees/Ea > 0.68 and Ees/Ea < 0.68 subgroups demonstrated constant RV stroke work but lower stroke volume (87.7 ± 22.1 vs. 60.1 ± 16.3 mL respectively, P = 0.006) and higher end‐systolic pressure (36.7 ± 11.6 vs. 68.1 ± 16.7 mmHg respectively, P < 0.001). Lower Ees/Ea in CTED also correlated with reduced exercise ventilatory efficiency. Low Ees/Ea aligns with features of RV maladaptation in CTED both at rest and on exercise. Characterization of Ees/Ea in CTED may allow for better identification of occult RV dysfunction.

Setting Up an Efficient Therapeutic Hypothermia Team in Conscious ST Elevation Myocardial Infarction Patients: A UK Heart Attack Center Experience

Patients presenting with ST elevation myocardial infarction (STEMI) are routinely treated with percutaneous coronary intervention to restore blood flow in the occluded artery to reduce infarct size (IS). However, there is evidence to suggest that the restoration of blood flow can cause further damage to the myocardium through reperfusion injury (RI). Recent research in this area has focused on minimizing damage to the myocardium caused by RI. Therapeutic hypothermia (TH) has been shown to be beneficial in animal models of coronary artery occlusion in reducing IS caused by RI if instituted early in an ischemic myocardium. Data in humans are less convincing to date, although exploratory analyses suggest that there is significant clinical benefit in reducing IS if TH can be administered at the earliest recognition of ischemia in anterior myocardial infarction. The Essex Cardiothoracic Centre is the first UK center to have participated in administering TH in conscious patients presenting with STEMI as part of the COOL-AMI case series study. In this article, we outline our experience of efficiently integrating conscious TH into our primary percutaneous intervention program to achieve 18 minutes of cooling duration before reperfusion, with no significant increase in door-to-balloon times, in the setting of the clinical trial.

The impact of coronary chronic total occlusion percutaneous coronary intervention upon donor vessel fractional flow reserve and instantaneous wave-free ratio: Implications for physiology-guided PCI in patients with CTO

To investigate the immediate and short term impact of right coronary artery (RCA) chronic total coronary occlusion (CTO) percutaneous coronary intervention (PCI) upon collateral donor vessel fractional flow reserve (FFR) and instantaneous wave‐free ratio (iFR).

23 The influence of collateral regression post coronary chronic total occlusion (cto) percutaneous coronary intervention (pci) on donor vessel coronary pressure-derived measurements

Background There is strong evidence of FFR guided treatment in multi-vessel disease. The presence of a concomitant CTO may influence the FFR measurement in donor vessel as suggested in previous studies and reports. This has an important implication on clinical decision making for complete revascularisation in patients with chronic total occlusion. We sought to investigate the influence of collateral regression after successful CTO recanalisation on donor vessel pressure-derived indices. Methods The study participants were patients with angina who had RCA CTO. 28 out of 34 consecutive patients underwent successful PCI to RCA CTOs during the study period and completed the follow study (at 3 months post CTO PCI) were included in this analysis. Coronary pressure-derived indices (resting PD/PA, iFR and FFR) were measured pre and post successful RCA CTO PCI in donor vessels and at follow up procedures. Results The mean age was 62.38 years. The mean estimated CTO duration was 238.72 weeks and CTO length was 32.44 mm. 25 patients had ischaemia and or viability in the RCA territory assessed with cardiac MRI. LAD was the major donor vessel in 24 patients and LCX was the minor donor vessel in 4 patients. Percent stenosis on QCA in the major and minor donor vessel were 40.6% and 35.1% respectively. The mean resting Pd/Pa, iFR and FFR pre and post RCA CTO PCI and at follow-up procedures in major donor vessel were (0.893, 0.862, 0.764), (0.907, 0.886, 0.753) and (0.918, 0.901, 0.787) respectively. The mean resting Pd/Pa, iFR and FFR pre and post RCA CTO PCI and at follow-up procedures in minor donor vessel were (0.979, 0.966, 0.890), (0.983, 0.979, 0.880) and (0.981, 0.974, 0.898) respectively. The changes in coronary pressure-derived indices pre and post RCA CTO PCI and at follow up procedures are summarised in table 1. In major donor vessel, there was significant changes in the difference between follow up and pre-CTO PCI values for Pd/Pa, iFR and FFR values (p values 0.006, 0.003 and 0.047 respectively). There was also significant change in the difference between follow up and post-CTO PCI FFR value (P value 0.002). FFR collateral reduced significantly at follow-up (p value 0.000). Conclusion Successful recanalisation of a RCA CTO results in increase in major donor vessel coronary pressure-derived indices at follow up procedure associated with the regression of collateral function. In patients with multi-vessel disease, the expected change and the optimal timing to perform PCI in donor vessel should be considered when planning multi-vessel revascularisation in this setting.Abstract 23 Table 1 Coronary pressure-derived indices pre and post RCA CTO PCI and at follow up procedures (FU:Follow-up, PCI:Percutaneous Coronary Intervention, FFR: Fractional Flow Reserve, CTO: Chronic Total Occlusion)

24 The physiological impact of coronary chronic total occlusion (cto) percutaneous coronary intervention (pci) on donor vessel coronary pressure-derived measurements and the influence of collateral circulation

Background There is strong evidence of FFR guided treatment in multi-vessel disease. Multi-vessel disease is present in up to 66% of patients with CTO in a large registry analysis. The presence of a concomitant CTO may influence the FFR measurement in donor vessel as suggested in previous studies and reports. This has an important implication on clinical decision making for complete revascularisation in patients with chronic total occlusions. There is a growing interest on the influence of collateral circulation, flow, amount of myocardium supplied by donor artery to a CTO and the impact of CTO revascularisation on donor vessel pressure-derived indices. We sought to investigate the physiological impact of CTO recanalisation on donor vessel pressure-derived indices. Methods The study participants were patients with angina who had RCA CTO. 34 out of 40 consecutive patients underwent successful PCI to RCA CTOs during the study period were included in the analysis. Coronary pressure-derived indices (resting Pd/Pa, iFR and FFR) were measured pre and post successful RCA CTO PCI in donor vessels. Donor vessel characteristics were graded using the Rentrop and colloateral connexion grading classification. Results The mean age was 61.76 years. The mean estimated CTO duration was 238.72 weeks and CTO length was 32.44 mm. 31 patients had ischaemia and or viability in the RCA territory assessed with cardiac MRI. LAD was the predominant donor vessel in 30 patients and LCX was the minor donor vessel in 4 patients. Percent stenosis on QCA in the predominant and minor donor vessel were 41.43% and 35.05% respectively. The angiographic details are as outlined in table 1. The mean resting Pd/Pa, iFR and FFR pre and post RCA CTO PCI in major donor vessel were (0.891, 0.858, 0.759) and (0.903, 0.882, 0.746) respectively. iFR in the major donor vessel increased from 0.858 to 0.882 (difference, 0.02412 (0.00573 to 0.04250); p=0.012). There were no significant difference in resting Pd/Pa and FFR pre and post CTO PCI (p=0.109 and p=0.388 respectively). The mean resting Pd/Pa, iFR and FFR pre and post RCA CTO PCI in minor donor vessel were (0.982, 0.969, 0.894) and (0.985, 0.979, 0.885) respectively. There were no significant difference in resting Pd/Pa, iFR and FFR pre and post CTO PCI in minor donor vessel (p=0.534, p=0.152, p=0.183 respectively). The mean collateral FFR was 0.310. The mean total ischaemic burden on baseline cardiac MRI in RCA territory was 12.6%. Conclusion Successful recanalisation of a RCA CTO results in increase in iFR but no significant difference was seen in resting Pd/Pa and FFR pre-RCA CTO PCI and immediately post recanalisation in predominant donor vessel. Complete collateral regression was not observed in all patients immediately post RCA CTO PCI and this may account for the non-significant change in FFR values.Abstract 24 Table 1 Angiographic Characteristics

THE ACUTE EFFECTS OF SELECTIVE SITE RIGHT VENTRICULAR PACING ON LEFT AND RIGHT VENTRICULAR HEMODYNAMIC FUNCTION IN A NORMAL HEART POPULATION

Right Ventricular Apical (RVA) pacing causes a non-physiological activation of the myocardium and can be associated with clinical complications. Clinical evidence supporting a benefit to pacing in alternative RV sites is conflicted. The present study was undertaken using conductance catheters to