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.

Performance of the AusSCORE II and STS Score for Coronary Artery Bypass Grafting in a New Zealand Population.

BACKGROUND: The updated Australian System for Cardiac Operative Risk Evaluation (AusSCORE II) and the Society of Thoracic Surgeons (STS) Score are well-established tools in cardiac surgery for estimating operative mortality risk. No validation analysis of both risk models has been undertaken for a contemporary New Zealand population undergoing isolated coronary bypass surgery. We therefore aimed to assess the efficacy of these models in predicting mortality for New Zealand patients receiving isolated coronary artery bypass grafting (CABG). MATERIAL AND METHODS: A prospective database was maintained of patients undergoing isolated CABG at a major tertiary referral centre in New Zealand between September 2014 and September 2017. This database collected the patients' demographic, clinical, biochemical, operative and mortality data. The primary outcome measure was the correlation between the predicted AusSCORE II and STS Score mortality risks and the observed 30-day mortality events for all patients in the database using discrimination and calibration statistics. Discrimination and calibration were assessed using receiver operating characteristic (ROC) curves and the Hosmer-Lemeshow test respectively. RESULTS: A total of 933 patients underwent isolated CABG during the 3-year study period. There were seven deaths in the study cohort occurring within 30 days of surgery. Discrimination analysis demonstrated the area under the ROC curve (AUC) of the AusSCORE II and STS Score as 88.2% (95% CI: 85.9-90.2, p<0.0001) and 92.1% (95% CI: 90.2-93.7, p<0.0001) respectively. Calibration analysis revealed Hosmer-Lemeshow test p-values for the AusSCORE II and STS Score as 0.696 and 0.294 respectively. DISCUSSION: ROC curve analysis produced very high and statistically significant AUC values for the AusSCORE II and STS Score. Hosmer-Lemeshow test analysis revealed that both risk scoring tools are well calibrated for our study cohort. Therefore, the AusSCORE II and STS Score are both strongly predictive of 30-day mortality for isolated coronary artery bypass grafting surgery in our New Zealand patient population. Both risk models have performed with excellent discrimination and calibration. There is, however, a need to consider the performance of these risk stratification models in other cardiac surgical procedures outside isolated coronary bypass surgery where appropriate.

Assessment of the EuroSCORE II in a New Zealand Tertiary Centre.

BACKGROUND: The updated European System for Cardiac Operative Risk Evaluation (EuroSCORE II) is a well-established cardiac surgery risk scoring tool for estimating operative mortality. This risk stratification system was derived from a predominantly European patient cohort. No validation analysis of this risk model has been undertaken for the New Zealand population across all major cardiac surgery procedures. We aim to assess the efficacy (discrimination and calibration) of the EuroSCORE II for predicting mortality in cardiac surgical patients at a large New Zealand tertiary centre. METHODS: Data was prospectively collected on patients undergoing cardiac surgery from September 2014 to September 2017 at Waikato Hospital, New Zealand. Patient demographic information, preoperative clinical risk factors and outcome data were entered into a national database. Included patients received either isolated coronary artery bypass grafting (CABG), isolated valve surgery, isolated thoracic aortic surgery, or a combination of these procedures. The primary outcome was the discrimination and calibration of predicted EuroSCORE II risk scores compared with observed 30-day mortality events. RESULTS: 1,666 cardiac surgery patients were included during the study period, with an average EuroSCORE II of 2.97% (95% confidence interval (CI): 2.76-3.18). Nine hundred thirty-three (933) patients underwent isolated CABG, 384 underwent isolated valve surgery, 48 received isolated thoracic aortic surgery and 301 received combination procedures. Thirty-day (30-day) mortality events in each of these groups was 7, 4, 2 and 13 deaths respectively. There were 26 deaths across the total cohort at 30-days (observed mortality rate 1.56%). Discrimination analysis using receiver operating characteristic curves demonstrated the area under the curve (AUC) of the EuroSCORE II in each of these groups as 93.4% (95% CI: 91.6-94.9, p<0.0001), 66.3% (95% CI: 61.3-71.0, p=0.37), 37.0% (95% CI: 15.7-58.2, p=0.23) and 74.8% (95% CI: 69.5-79.6, p<0.0001) respectively. The total cohort AUC was 83.1% (95% CI: 81.2-84.9, p<0.0001). Calibration analysis using Hosmer-Lemeshow tests for the subgroups revealed p-values of 0.848, 0.114, 0.638 and 0.2 respectively. The total cohort Hosmer-Lemeshow p-value was 0.317. CONCLUSIONS: EuroSCORE II showed a strong discriminative ability for isolated CABG 30-day mortality in a New Zealand patient cohort. However, the scoring system discriminated poorly across valvular, thoracic aortic or complex combination cardiac surgical procedures. Good calibration of the EuroSCORE II was achieved across both the total cohort and subgroups. It is important to consider the performance of other cardiac surgery risk stratification models for the New Zealand population.

Early Discharge From Intensive Care After Cardiac Surgery is Feasible With an Adequate Fast Track, Stepdown Unit: Waikato Experience.

BACKGROUND: Enhanced recovery programs within cardiothoracic surgery are a well described benefit to patient postoperative outcomes. We describe our Australasian unit's experience of a day zero discharge enhanced recovery unit from the intensive care department. METHODS: A retrospective study was conducted on a prospectively maintained database at Waikato Cardiothoracic Unit from September 2014 till October 2017 with 1,739 patients undergoing cardiac surgery. Twenty-two (22) patients were excluded as deaths either intraoperative or in the intensive care unit (ICU) and therefore never discharged. Total population of the study was 1,717 patients. The primary endpoint of this study was to determine if there is no survival disadvantage for the day zero discharge unit compared to standard treatment in ICU at follow-up. The secondary endpoint of the study was to highlight the association between pre and postoperative variables and the impact on discharge from the ICU. RESULTS: One hundred sixty-eight (168) patients were discharged to the enhanced recovery unit (ERU) day zero. Mean number of hours spent in ICU for the day zero cohort was 7.18 (±1.59. Mean Age 62.5 (±11.22), M:F 4.25:1. Patients were more likely to be discharged day zero if they had a lower EuroSCORE II 1.57 (±1.67) and lower preoperative creatinine 89.4 (±27.5). Those admitted to the ERU on day zero postoperatively were more likely to be discharged with a lower creatinine level, a higher haemoglobin level and have less readmissions per 30days (p<0.05). Survival analysis demonstrated that the patients who were discharged early from ICU had significantly better follow-up survival compared to those who were discharged after 24hours (p<0.05). CONCLUSIONS: A fast track unit increases the efficiency of an ICU and cardiac surgical department. With the advancements of cardiac surgery a higher number of patients will be suitable for a fast track method. Our unit has demonstrated that a day zero fast track unit in New Zealand can perform with adequate patient safety with no increased risk of mortality and with low rates of failure of the day zero discharge fast track therapy.

A rare case of cholesterol granuloma in the anterior mediastinum.

Cholesterol granulomas are reactant lesions that develop in response to cholesterol crystals and foreign body giant cells. They are a commonly described benign condition affecting the middle ear and paranasal sinuses, however have been reported in various sites within the body. We describe a rare case of an incidental cholesterol granuloma in the anterior mediastinum of a cardiac surgical patient.

How I do it: repair of sternal fracture with bone graft and plating.

Described here is a technique of using bone graft and plating for fixation of traumatic sternal fractures with non-union. We recommend involvement of an orthopedic surgeon and consideration of bone graft use in sternal fractures where there is likely to be large gap between sternal edges.

Bilateral costal cartilage fractures sustained in the gym during repeated bench press exercises.

Costal cartilage fractures are common in high-energy blunt chest trauma but are frequently missed on imaging evaluation and accordingly underreported in the literature. In this report, we describe a case of a 32-year-old male who sustained bilateral costal cartilage fractures following repeated blunt trauma in the gym sustained during bench press exercises. The patient presented with a painful "clicking" of a rib in and out of place while bending or turning sideways. Initial chest X-ray and computed tomography (CT) imaging were reported negative for fractures; however, a closer inspection of the CT image revealed bilateral costal cartilage fractures. As the patient's symptoms improved over time, a conservative approach to treatment with regular analgesia and advice to avoid external impact on the fracture sites was adopted. This unique case highlights an unusual mode of trauma and diagnostic complexity of costal cartilage fractures.

Cardiac surgery simulation: a low-cost feasible option in an Australasian setting.

BACKGROUND: Simulation training is a useful adjunct to surgical training and education (SET) in Cardiothoracic Surgery yet training opportunities outside the Royal Australasian College of Surgery or industry-sponsored workshops are rare due to high cost and limited training faculty, time, assessment tools or structured curricula. We describe our experience in establishing a low-cost cardiac simulation programme. METHODS: We created low-cost models using hospital facilities, hardware stores, abattoirs and donations from industry. Three workshops were conducted on coronary anastomoses, aortic and mitral valve replacement. RESULTS: Whole porcine hearts were sourced from local farms. Industry donations of obsolete stock were used for suture and valve material-stations constructed using ironing-board, 2-L buckets and kebab-skewers. Suture ring holders were fashioned from recycled cardboard or donated. All participants were asked to complete pre and post simulation self-assessment forms. Across three workshops, 45 participants (57.8% female) with a median age 27 (interquartile range 24-31) attended. Training level consisted of nurses (8, 17.8%), medical students (17, 37.8%), residents/house officers (6, 13.3%) and registrars (14, 31.1%). There were improvements in knowledge of anatomy (mean difference 18%; 95% confidence interval 12%-24%), imaging (16%; 10%-22%) and procedural components (34%; 28%-42%); and practical ability to describe steps (30%; 24%-38%), partially (32%; 26%-38%) or fully complete (32%; 28%-38%) the procedure. CONCLUSIONS: Simulation-based training in cardiac surgery is feasible in a hospital setting with low overhead costs. It can benefit participants at all training levels and has the potential to be implemented in training hospitals as an adjunct to the SET programme.

Desmoid fibromatosis of the chest wall.

We report a case of desmoid fibromatosis of the chest wall. A 70-year-old woman was referred to our hospital with right shoulder blade pain and paresthesia over the right upper breast. Chest X-ray and computed tomography demonstrated a 5 cm right apical mass in the chest. Biopsy of the mass demonstrated features of desmoid fibromatosis. The patient subsequently underwent surgical resection of the mass and received adjuvant radiation therapy for microscopic positive margins. In conclusion, although desmoid tumour of the chest is rare, it is worth considering in the differential diagnoses of chest wall tumours.

Urgent and emergency coronary artery bypass grafting for acute coronary syndromes.

BACKGROUND: Urgent and emergency coronary artery bypass grafting may be associated with significant mortality and morbidity. We report our recent experience with this group of patients. METHODS: A retrospective analysis of 441 patients undergoing urgent and emergency surgery over a 3-year period was carried out. Multivariate analysis was used to identify subgroups of patients who were most at risk of death. RESULTS: The 30-day mortality was 3.3 and 16.3% in the urgent and emergency groups, respectively. Urgent surgery was associated with significantly shorter duration of ventilation (16 h vs 69 h) and stay at the intensive care unit (31 h vs 102 h). The incidence of pneumonia, pulmonary embolism, renal failure and neurological events were also less in the urgent group. The preoperative use of the intra-aortic balloon pump was low (0.8% in the urgent group and 4.8% in the emergency group). Multivariate analysis showed that patients over 70 years of age (odds ratio 3.2, 95% confidence interval 1.1-9.5) with left main stenosis (odds ratio 4.4, 95% confidence interval 1.5-12.4) complicated by cardiogenic shock (odds ratio 17.8, 95% confidence interval 5.2-61.1) were at highest risk of death. Patients transferred directly to theatre from cardiac catheter laboratory following failed percutaneous interventions were found to be most at risk. Mortality in this group was 29%, with 50% patients being in shock and 36% having left main stenosis. CONCLUSION: Satisfactory results have been obtained in urgent coronary artery bypass grafting, but acute coronary syndromes complicated by cardiogenic shock remain a high-risk group. Further studies are needed to define the optimal operative management in this group of patients.

Experience with unipolar radiofrequency ablation for atrial fibrillation.

BACKGROUND: The cut and sew Cox maze procedure for atrial fibrillation (AF), although effective, is not widely used because of technical complexity, prolonged duration and significant risk of postoperative bleeding. This study reviews our experience with the unipolar radiofrequency ablation (RFA) procedure, which was used to create a modified maze to treat AF. METHODS: A retrospective review of 31 patients undergoing consecutive cardiac surgery who had concomitant RFA for AF over a 16-month period was carried out. A Cobra unipolar RFA probe (EPT; Boston Scientific, San Jose, CA, USA) was used to create a standard set of lesions. RESULTS: There were 20 men and 11 women (mean age, 66 +/- 9 years; range, 48-87 years). AF was continuous in 21 patients and intermittent in 10. The median duration of AF leading up to surgery was 48 months (range, 6 months-20 years). Left atrium was enlarged in 81% of the patients. Operations included mitral valve repair (7 patients), replacement (5), coronary artery bypass (10), aortic valve replacement (1) and combined procedures (8). There were no complications directly attributable to RFA. There were three early deaths. One patient required a permanent pacemaker. Median follow up was 22 months (range, 12-30 months). One patient died 2 years after the operation from a stroke. Cardioversion was attempted in five patients within 3 months of operation and was successful in four. At 2 years following the procedure, the probability of the patient remaining in sinus rhythm was 0.71 +/- 0.15. CONCLUSION: Surgical RFA can be carried out as a useful adjunct to conventional cardiac surgery. Although the results were satisfactory in this series, further studies are needed to refine the indication of the procedure and to assess its longer-term efficacy.

Use of a single silastic chest drain following thoracotomy: initial evaluation.

BACKGROUND: It is standard practice to use multiple large bore semi-rigid chest tubes to drain the pleural cavity following thoracic procedures. These can cause pain and discomfort at the insertion site. METHODS: We describe our experience with the use of a single small silastic drain following thoracotomy. From November 2001 to November 2003, size 19-F silastic chest tubes (Blake drains) were used for drainage of the pleural cavity in 37 patients at our institution. The patients ranged in age from 18 to 81 years (mean 65). The operations included 22 lobectomies, two bilobectomies, 10 wedge resections, and three other procedures. RESULTS: Total drainage in each patient ranged from 420 to 5440 mL (mean 1387 mL). Tubes were left in place for an average of 4.3 days (range 1-12). The average postoperative length of stay was 7.6 days (range 3-44, median 5). Three patients required insertion of an additional tube for dislodgement, persistent air leak, and bronchopleural fistula, respectively. These complications occurred among the first 15 patients in the present series. None of the patients had persistent pleural effusion. Subjectively, these tubes were more comfortable for the patients and were easier to remove. SUMMARY: The use of a single, small silastic chest drains following thoracotomy may be safe and effective in draining both fluid and air, though an additional tube may be necessary for persistent leaks.

Tricuspid valve repair for torrential tricuspid regurgitation after permanent pacemaker lead extraction.

Tricuspid regurgitation secondary to percutaneous lead extraction is uncommon, and it rarely requires surgical intervention. Most tricuspid regurgitation occurs during the implantation of tined leads, which can be entrapped in the tricuspid valve apparatus and may require immediate withdrawal. Severe tricuspid regurgitation as a sequela of extracting chronically implanted leads has rarely been reported. Herein, we report a case of torrential tricuspid regurgitation in a 67-year-old woman after the extraction of a permanent pacemaker lead. The regurgitation was confirmed on transesophageal echocardiography during lead extraction, and the tricuspid valve was successfully repaired with suture bicuspidization of the valve and the support of ring annuloplasty. A short review of the relevant literature follows the case report.