John Yap

Effect of remote ischaemic preconditioning on clinical outcomes in patients undergoing cardiac bypass surgery: a randomised controlled clinical trial

Objectives Remote ischaemic preconditioning (RIPC), using brief cycles of limb ischaemia/reperfusion, is a non-invasive, low-cost intervention that may reduce perioperative myocardial injury (PMI) in patients undergoing cardiac surgery. We investigated whether RIPC can also improve short-term clinical outcomes. Methods One hundred and eighty patients undergoing elective coronary artery bypass graft (CABG) surgery and/or valve surgery were randomised to receive either RIPC (2–5 min cycles of simultaneous upper arm and thigh cuff inflation/deflation; N=90) or control (uninflated cuffs placed on the upper arm and thigh; N=90). The study primary end point was PMI, measured by 72 h area under the curve (AUC) serum high-sensitive troponin-T (hsTnT); secondary end point included short-term clinical outcomes. Results RIPC reduced PMI magnitude by 26% (−9.303 difference (CI −15.618 to −2.987) 72 h hsTnT-AUC; p=0.003) compared with control. There was also evidence that RIPC reduced the incidence of postoperative atrial fibrillation by 54% (11% RIPC vs 24% control; p=0.031) and decreased the incidence of acute kidney injury by 48% (10.0% RIPC vs 21.0% control; p=0.063), and intensive care unit stay by 1 day (2.0 days RIPC (CI 1.0 to 4.0) vs 3.0 days control (CI 2.0 to 4.5); p=0.043). In a post hoc analysis, we found that control patients administered intravenous glyceryl trinitrate (GTN) intraoperatively sustained 39% less PMI compared with those not receiving GTN, and RIPC did not appear to reduce PMI in patients given GTN. Conclusions RIPC reduced the extent of PMI in patients undergoing CABG and/or valve surgery. RIPC may also have beneficial effects on short-term clinical outcomes, although this will need to be confirmed in future studies. Trial registration number ClinicalTrials.gov ID: NCT00397163.

A retrospective analysis of myocardial preservation techniques during coronary artery bypass graft surgery: are we protecting the heart?

BackgroundRetrograde perfusion into coronary sinus during coronary artery bypass graft (CABG) surgery reduces the need for cardioplegic interruptions and ensures the distribution of cardioplegia to stenosed vessel territories, therefore enhancing the delivery of cardioplegia to the subendocardium. Peri-operative myocardial injury (PMI), as measured by the rise of serum level of cardiac biomarkers, has been associated with short and long-term clinical outcomes. We conducted a retrospective analysis to investigate whether the combination of antegrade and retrograde techniques of cardioplegia delivery is associated with a reduced PMI than that observed with the traditional methods of myocardial preservation.MethodsFifty-four consecutive patients underwent CABG surgery using either antegrade cold blood cardioplegia (group 1, n = 28) or cross-clamp fibrillation (group 2, n = 16) or antegrade retrograde warm blood cardioplegia (group 3, n = 10). The study primary end-point was PMI, evaluated with total area under the curve (AUC) of high-sensitivity Troponin-T (hsTnT), measured pre-operatively and at 6, 12, 24, 48 and 72 hours post-surgery. Secondary endpoints were acute kidney injury (AKI) and inotrope scores, length of intensive care unit (ICU) and hospital stay, new onset atrial fibrillation (AF) and clinical outcomes at 6 weeks (death, non-fatal myocardial infarction, coronary artery revascularization, stroke).ResultsThere was evidence that mean total AUC of hsTnT was different among the three groups (P = 0.050). In particular mean total AUC of hsTnT was significantly lower in group 3 compared to both group 1 (-16.55; 95% CI: -30.08, -3.01; P = 0.018) with slightly weaker evidence of a lower mean hsTnT in group 3 when compared to group 2 (-15.13; 95% CI -29.87, -0.39; P = 0.044). There was no evidence of a difference when comparing group 2 to group 1 (-1.42,; 95% CI: -12.95, 10.12, P = 0.806).ConclusionsOur retrospective analysis suggests that, compared to traditional methods of myocardial preservation, antegrade retrograde cardioplegia may reduce PMI in patients undergoing first time CABG surgery.

A new transcatheter heart valve concept (the TRISKELE): feasibility in an acute preclinical model

AIMS The aim of this study was to introduce and demonstrate the feasibility in an acute preclinical model of a new transcatheter heart valve concept with a self-expanding wire frame, polymeric leaflets and a sealing component. METHODS AND RESULTS The TRISKELE valve was developed based on a previously validated polymeric leaflet design, an adaptive sealing cuff and a novel nitinol wire frame which reduces stress on the leaflets and radial pressure on the surrounding tissue. A valve prototype of 26 mm nominal diameter was manufactured by automated dip coating of a biostable polymer. The prototype was implanted via brachiocephalic approach in orthotopic position in an acute ovine model through a highly controllable multistage deployment process. The atraumatic retrievability of the valve after full expansion was verified in situ before final release in the optimal position. Observation indicated secure valve anchoring, adequate leaflet motion, and no interference of coronary flow or mitral valve function. CONCLUSIONS The TRISKELE valve system has the potential to mitigate complications related to imprecise valve positioning, and may offer a safer and more economical TAVI solution to a broad range of patients. The valve is currently under preclinical investigation for its long-term function and durability.

Predictors of clinical outcome in transfemoral TAVI: Circumferential iliofemoral calcifications and manufacturer-derived recommendations

Objective: This study aimed to investigate the predictive value of circumferential iliofemoral calcifications and current manufacturer recommendations, which are not evidence-based, in transfemoral (TF) transcatheter aortic valve implantation (TAVI) Methods: A patient cohort with a broad range of iliofemoral anatomies undergoing TF TAVI (n=132) were retrospectively divided as “suitable” (n=76, 58%) and “unsuitable” (n=56, 42%) candidates according to current recommendations. Iliofemoral angiography and reconstructed mul- tislice CT (MSCT) images were used for access screening in the majority of patients. Results: Vessel properties were significantly worse in the “unsuitable group.” The sheath-to-iliofemoral artery ratio (SIFAR) and calcium score were 1.35±0.2 and 1.7±0.8 in the unsuitable group, compared to 1.0±0.12 (p<0.0001) and 1.0±0.7 (p=0.0001) in the “suitable” patients. Major vascular complications (MVCs) occurred more frequently in the “unsuitable” group (10.7% vs. 2.6%, p=0.07) and were predicted by SIFAR [OR: 64, 95% CI: 1.4-2971, p=0.03] and circumferential iliofemoral calcifications [OR: 6, 95% CI: 1.2-26, p=0.025]. In the multivariate analysis, circumferential calcifications [HR: 3.6, 95% CI: 1-13.2, p=0.043] but not major vascular complications (MVCs) or manufacturer recommendations were associated with increased mortality. Conclusion: According to our results, manufacturer recommendations are safe but overly conservative. Circumferential iliofemoral calcifications may provide independent prognostic information in patients undergoing TAVI.

Postoperative morbidity after surgical aortic valve replacement or transcatheter valve implantation: a prospective cohort study

Postoperative morbidity after surgical aortic valve replacement or transcatheter valve implantation: a prospective, cohort study. Dr. Akshay Shah, Cardiac Intensive Care Unit, The Heart Hospital, UCLH, London, United Kingdom (Corresponding author) Dr. Helen Brambley, Cardiac Intensive Care Unit, The Heart Hospital, UCLH, London, United Kingdom Mr. Miles Curtis, The Heart Hospital, UCLH, London, United Kingdom Dr. Michael Mullen, The Heart Hospital, UCLH, London, United Kingdom Ms. Nicola Delahunty, The Heart Hospital, UCLH, London, United Kingdom Mr. John Yap, Cardiac Intensive Care Unit, The Heart Hospital, UCLH, London, United Kingdom Dr. Andrew Smith, Cardiac Intensive Care Unit, The Heart Hospital, UCLH, London, United Kingdom Professor Hugh Montgomery, UCL Institute for Human Health and Performance, University College London, London, United Kingdom Dr. Julie Sanders, UCL Institute for Human Health and Performance, University College London, London, United Kingdom