Thomas Keeble

Impact of Percutaneous Revascularization on Exercise Hemodynamics in Patients With Stable Coronary Disease

Background Recently, the therapeutic benefits of percutaneous coronary intervention (PCI) have been challenged in patients with stable coronary artery disease (SCD). Objectives The authors examined the impact of PCI on exercise responses in the coronary circulation, the microcirculation, and systemic hemodynamics in patients with SCD. Methods A total of 21 patients (mean age 60.3 ± 8.4 years) with SCD and single-vessel coronary stenosis underwent cardiac catheterization. Pre-PCI, patients exercised on a supine ergometer until rate-limiting angina or exhaustion. Simultaneous trans-stenotic coronary pressure-flow measurements were made throughout exercise. Post-PCI, this process was repeated. Physiological parameters, rate-limiting symptoms, and exercise performance were compared between pre-PCI and post-PCI exercise cycles. Results PCI reduced ischemia as documented by fractional flow reserve value (pre-PCI 0.59 ± 0.18 to post-PCI 0.91 ± 0.07), instantaneous wave-free ratio value (pre-PCI 0.61 ± 0.27 to post-PCI 0.96 ± 0.05) and coronary flow reserve value (pre-PCI 1.7 ± 0.7 to post-PCI 3.1 ± 1.0; p < 0.001 for all). PCI increased peak-exercise average peak coronary flow velocity (p < 0.0001), coronary perfusion pressure (distal coronary pressure; p < 0.0001), systolic blood pressure (p = 0.01), accelerating wave energy (p < 0.001), and myocardial workload (rate-pressure product; p < 0.01). These changes observed immediately following PCI resulted from the abolition of stenosis resistance (p < 0.0001). PCI was also associated with an immediate improvement in exercise time (+67 s; 95% confidence interval: 31 to 102 s; p < 0.0001) and a reduction in rate-limiting angina symptoms (81% reduction in rate-limiting angina symptoms post-PCI; p < 0.001). Conclusions In patients with SCD and severe single-vessel stenosis, objective physiological responses to exercise immediately normalize following PCI. This is seen in the coronary circulation, the microcirculation, and systemic hemodynamics.

Percutaneous haemodynamic and renal support in patients presenting with decompensated heart failure: A multi-centre efficacy study using the Reitan Catheter Pump (RCP)

BACKGROUND Worsening heart failure complicated by congestion, hypotension, and renal dysfunction is difficult to manage, increasingly common and predicts a poor outcome. Novel therapies are required to facilitate diuresis and implementation of disease-modifying interventions in preparation for hospital discharge. Accordingly, we investigated the haemodynamic and renal effects of the Reitan Catheter Pump (RCP) percutaneous support device in patients admitted with decompensated heart failure (DHF). METHODS This was a prospective observational study of 20 patients admitted with DHF, ejection fraction < 30%, and Cardiac index (CI) < 2.1 L/min/m2 in need of inotropic/mechanical support. RESULTS Patients underwent RCP support for a mean of 18.3 (±6.3) hours. The RCP increased CI from 1.84 L/min/m2 (±0.27), to 2.41 L/min/m2 (±0.45, p = 0.04), increased urine output (71 mL/h (±65) to 227 ml/h (±179) (p = 0.006) with a concomitant reduction in serum creatinine (188 μmol/L (±87) to 161 μmol/L (±78) (p = 0.0007). There were no clinically significant haemolysis, vascular injury, or thrombo-embolic complications. CONCLUSIONS For patients admitted with DHF, the RCP improves cardiac index, diuresis and renal function without causing important complications.

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

26 Setting up a neurological prognostication service in a tertiary cardiothoracic centre with no neuro-physiology service

Background Brain injury due to hypoxia, is the most common cause of mortality in patients that have been successfully resuscitated following Cardiac Arrest. The Essex Cardiothoracic Centre (CTC) is a tertiary cardiac centre where all cardiac arrest patients are triaged on arrival within the catheter lab. Here there is access to appropriate PCI and mild therapeutic hypothermia (32°C–33°C), which has increased the survival rate to 67% of all out of hospital arrest patients. Methods and results Previously the CTC has relied upon neurological clinical examination and CT for neurological prognostication, neither of which are appropriate for all patients. In 2014 the ERC and ESICM, suggest the use of a multimodal approach in normothermic and hypothermic patients. We aimed to test the feasibility of setting up a neurological prognostication service using a multimodal approach, with the use of EEG, SSEP and Biomarkers. We believe that by adhering to strict criteria, a multimodal approach can be used safely and effectively in a Cardiac Centre with no on-site neurophysiological support, for more accurate neurological prognostication. The staff have been trained over a 3 month period by external neurophysiology experts to record high quality 20 min EEG, sent to a core lab for analysis and SSEP, interpreted locally. Biomarkers are sent to a reference lab. Conclusion This feasibility study has shown that senior ICU staff can be trained in EEG/SSEP recordings, and can then be interpreted rapidly in a core lab to allow neuro-prognostication to occur in all cardiac centres. This is vital for the up-coming TTM2 trial in 2017.