Evaluation of the effects of three designs of oxygenators with integrated filters on clinical and haematological outcomes at an Australasian cardiothoracic unit.

INTRODUCTION: Cardiopulmonary bypass (CPB) machines have oxygenators with integrated filters and unique biocompatible coatings to combat systemic inflammatory response syndrome (SIRS) and mitigate coagulopathy. Contemporary oxygenators have undergone comparative studies; however, our study aimed to identify the most appropriate oxygenator for our regional Cardiothoracic unit in Australasia. METHODS: A prospective audit consecutively recruited one-hundred and fifty patients undergoing cardiac surgery at Waikato Hospital, New Zealand between the periods of 29th January 2018 and 31st July 2018. Fifty patients were recruited for each oxygenator arm: Sorin INSPIRE' (Group-S); Terumo CAPIOX'FX (Group-T); and Medtronic Affinity Fusion' (Group-M). The clinical outcomes were transfusions, chest drain output, reoperation and length of hospital stay (LOHS). Routine blood testing protocol included: haemoglobin, protein, albumin, white cell count (WCC), C-reactive protein (CRP), platelet count and coagulations tests including international normalized ratio (INR). RESULTS: Comparing Groups S, T and M there was no statistical difference in chest drain output (650 vs. 500 vs. 595 ml respectively, p = 0.45), transfusions (61 vs. 117 vs. 70 units, p = 0.67), reoperation (6 vs. 8 vs. 12%, p = 0.99) and LOHS (median 7.4 vs. 7.6 vs. 9.5 days, p = 0.42). Group-T had fewer SIRS cases but similar increase in CRP (p = 0.12) and WCC (p = 0.35). Group-M had a significant rise in post-op INR (p = 0.005) but no associated increase in chest drain output (p = 0.62). Group-S and -M required more 4%-albumin and Group-T had more transfusions. Only fresh frozen plasma (FFP) and red blood cell (RBC) transfusion had a significant relationship with LOHS (p < 0.05). CONCLUSION: Biochemically, there was slight difference among the oxygenators which did not translate into clinical difference in outcomes. The oxygenator design and perfusionist choice aided in our decision-making process.

Rib Cage Stabilisation With 3D-Printed Polyethylene Sternal Prosthesis Post-Sternotomy Mediastinitis.

BACKGROUND: Post-sternotomy mediastinitis (PSM) is a serious complication of median sternotomy. It is associated with a high mortality rate. Evidence based management recommends debridement followed by closure with vascularised flaps. When large areas of resections are performed, the use of sternal prosthesis could be considered to ensure chest wall stability and cosmesis. METHOD: We report an individualised three-dimensional (3D)-printed high-density polyethylene (HDPE) sternum implantation in a patient with a 10 cm chest wall defect. RESULTS: Chest wall reconstruction was uncomplicated and the patient tolerated the procedure well without cardiorespiratory compromise. Postoperatively, the wound healed well and the chest wall remained stable at outpatient clinic follow-up. CONCLUSION: Three-dimensional-printed HDPE prosthesis offers an alternative implant option for closing large chest wall defects for eroded sternum after cure of mediastinitis.

Extracorporeal Life Support Bridge to Ventricular Assist Device: The Double Bridge Strategy.

In patients requiring left ventricular assist device (LVAD) support, it can be difficult to ascertain suitability for long-term mechanical support with LVAD and eventual transplantation. LVAD implantation in a shocked patient is associated with increased morbidity and mortality. Interest is growing in the utilization of extracorporeal life support (ECLS) as a bridge-to-bridge support for these critically unwell patients. Here, we reviewed our experience with ECLS double bridging. We hypothesized that ECLS double bridging would stabilize end-organ dysfunction and reduce ventricular assist device (VAD) implant perioperative mortality. We conducted a retrospective review of prospectively collected data for 58 consecutive patients implanted with a continuous-flow LVAD between January 2010 and December 2013 at The Alfred Hospital, Melbourne, Victoria, Australia. Twenty-three patients required ECLS support pre-LVAD while 35 patients underwent LVAD implantation without an ECLS bridge. Preoperative morbidity in the ECLS bridge group was reflected by increased postoperative intensive care duration, blood loss, blood product use, and postoperative renal failure, but without negative impact upon survival when compared with the no ECLS group. ECLS stabilization improved end-organ function pre-VAD implant with significant improvements in hepatic and renal dysfunction. This series demonstrates that the use of ECLS bridge to VAD stabilizes end-organ dysfunction and reduces VAD implant perioperative mortality from that traditionally reported in these "crash and burn" patients.

Right ventricular failure after implantation of continuous flow left ventricular assist device: analysis of predictors and outcomes.

Postoperative right ventricular failure is a serious complication for up to 50% of patients following LVAD insertion. Predicting RV failure is an important factor for patients as planned BiVAD support has been shown to correlate with better outcomes compared to delayed BiVAD to LVAD conversion. This retrospective study examined prospectively collected data for 101 patients implanted with an LVAD between 2003 and 2013, aiming to establish preoperative predictive factors for RVF post-LVAD insertion, analyze outcomes, and validate existing RVF scoring systems. In our cohort, 63 patients (62.4%) developed RV failure and consequently demonstrated consistently poorer survival throughout the follow-up period (log-rank p = 0.01). Multivariable logistic regression identified two significant variables: cardiac index <2.2 preoperatively despite inotropic support (OR 4.6 [95%CI 1.8-11.8]; p = 0.001) and preoperative tricuspid regurgitation (OR 8.1 [95%CI 1.9-34]; p = 0.004). Patients who developed RV failure had more complicated postoperative courses including longer ICU stay (p < 0.001), higher incidence of transfusions (p = 0.03) and re-intubation (p = 0.001), longer ventilation duration (p < 0.001), and higher incidence of returning to theater (p = 0.0008). This study found that previous validation models had only moderate correlation with our population emphasizing the need for prospective validation of these scores in the current era of continuous flow devices.

Banding the Right Ventricular Assist Device Outflow Conduit: Is It Really Necessary With Current Devices?

Implantable left ventricular assist devices (LVADs) have been adapted clinically for right-sided mechanical circulatory support (RVAD). Previous studies on RVAD support have established the benefits of outflow cannula restriction and rotational speed reduction, and recent literature has focused on assessing either the degree of outflow cannula restriction required to simulate left-sided afterload, or the limitation of RVAD rotational speeds. Anecdotally, the utility of outflow cannula restriction has been questioned, with suggestion that banding may be unnecessary and may be replaced simply by varying the outflow conduit length. Furthermore, many patients have a high pulmonary vascular resistance (PVR) at the time of ventricular assist device (VAD) insertion that reduces with pulmonary vascular bed remodeling. It is therefore important to assess the potential changes in flow through an RVAD as PVR changes. In this in vitro study, we observed the use of dual HeartWare HVAD devices (HeartWare Inc., Framingham, MA, USA) in biventricular support (BiVAD) configuration. We assessed the pumps' ability to maintain hemodynamic stability with and without banding; and with varying outflow cannulae length (20, 40, and 60 cm). Increased length of the outflow conduit was found to produce significantly increased afterload to the device, but this was not found to be necessary to maintain the device within the manufacturer's recommended operational parameters under a simulated normal physiological setting of mild and severe right ventricular (RV) failure. We hypothesize that 40 cm of outflow conduit, laid down along the diaphragm and then up over the RV to reach the pulmonary trunk, will generate sufficient resistance to maintain normal pump function.

Long-term right ventricular support with a centrifugal ventricular assist device placed in the right atrium.

This case series outlines the technique and results of right ventricular assist device (RVAD) support with the off-label use of the centrifugal HeartWare HVAD (HeartWare Inc., Framingham, MA, USA) for long-term support. Four patients in our institution have been implanted with BiVADs, using the Heartware device as the RVAD, and supported for between 117 days and 772 days. Three of the patients have been successfully supported for over 18 months. Three patients have successfully been transplanted and one patient remains on the device, now approaching two years of support. None of the patients have had RVAD device-related complications.

Endovascular repair of iatrogenic aortic rupture.

Thoracic endovascular aortic repair (TEVAR) has been used for traumatic and acute spontaneous rupture of the descending thoracic aorta with good results. We present the case of a 40-year-old male whose thoracic spinal prosthesis eroded through the descending thoracic aorta; the aortic disruption was successfully managed with emergent deployment of an endovascular stent.

What are the endovascular options and outcomes for repair of ascending aortic or aortic arch pathology?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was 'in patients with ascending aortic or aortic arch disease what are the outcomes with endovascular repair in terms of survival, complications and reintervention?' Altogether 585 papers were found using the reported search, of which 9 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. We found that the endovascular operative techniques with the greatest evidence were ascending aortic chimney grafts (AACs), branched thoracic endovascular aortic repair (bTEVAR) aortic grafts and fenestrated TEVAR (fTEVAR) aortic grafts. The best evidence available were small case-series or retrospective cohort studies (n < 100), with 1 systematic review, at a short follow-up period (range 0-5 years). Intraoperatively, these techniques have a high technical success rate (84-100%). We found rates of endoleak comparable between AAC (7.4-16%) and bTEVAR/fenestrated TEVAR (11.1-21.4%). Stroke rates are higher in bTEVAR (3.1-42% vs 1-26% in AACs), attributed to more proximal pathology and technically challenging procedures. Following the immediate postoperative period, the 30-day mortality is 0-10.8% and patency is 97-100%. Stroke and reintervention rates remain higher in the bTEVAR group (3.1-42.0% and 0.5-33.3%) compared to the AAC group (1.0-11.1% and 6.7-16.7%). The 3- and 5-year survival ranges from 59% to 90%, but is driven by non-aortic pathology in a high-risk population; 3-year freedom from aortic death is 93-97%. Patency is 97-100% at up to 3 years, conformation and supra-aortic occlusions thereafter remain unknown. We conclude that AACs, bTEVARs and fenestrated TEVARs are safe endovascular options in high-risk elective patients, with results comparable to open or hybrid repair. They remain unverified in acute settings or in patients fit for open intervention.