Optimal Conduit Diameter Selection in Coronary Bypass Grafting Using Saphenous Vein.

BACKGROUND: Predictors of long-term saphenous vein graft (SVG) patency following coronary artery bypass grafting (CABG) include harvesting technique, degree of proximal coronary stenosis, and target vessel diameter and runoff. The objective of this study was to evaluate the association between vein graft diameter and long-term survival. METHODS: Patients undergoing primary CABG (2000-2017) at Flinders Medical Centre, Adelaide, Australia, were categorised into three groups according to average SVG diameter (<3.5 mm [small], 3.5-4 mm [medium], >4 mm [large]). Survival data was obtained from the Australian Institute of Health and Welfare National Death Index. To determine the association of SVG diameter with long-term survival we used Kaplan-Meier survival analysis and Cox proportional hazard models adjusted for preoperative variables associated with survival. RESULTS: Vein graft diameter was collected in 3,797 patients. Median follow-up time was 7.6 years (interquartile range, 3.9-11.8) with 1,377 deaths. SVG size >4 mm was associated with lower rates of adjusted survival up to 4 years postoperatively (hazard ratio 1.48; 95% confidence interval 1.05-2.1; p=0.026). CONCLUSIONS: Vein graft diameter >4mm was found to be associated with lower rates of survival following CABG.

Quantification of the internal mammary artery size in Aboriginal and Torres Strait islanders.

BACKGROUND: Variation in size of the internal mammary artery has been demonstrated in ethnic groups, but not reported in Aboriginal patients. We hypothesised that the left internal mammary artery is smaller in Aboriginal patients compared to non-Aboriginal patients and aimed to determine the impact on survival following coronary artery bypass graft (CABG) surgery. METHODS: Left internal mammary artery size was compared between Aboriginal (n = 345) and non-Aboriginal (n = 1819) in 2343 patients undergoing CABG at Flinders Medical Centre from January 2010 to June 2021. To determine the association with-survival we used Kaplan-Meier survival analysis and Cox proportional hazard models adjusted for preoperative variables. RESULTS: There was a significant difference in left internal mammary artery (LIMA) size-Aboriginal 1.8 ± 0.4 mm; non-Aboriginal 2.1 ± 0.4 mm (P < 0.001)-and left anterior descending (LAD) artery size-Aboriginal 1.7 ± 0.3 mm; non-Aboriginal 1.9 ± 0.3 mm (P < 0.001). Aboriginal patients were more likely to have the LIMA discarded (9.3% vs. 0.4%) and to receive a LAD vein graft (17% versus 3%) (P < 0.001). There was no difference in 30-day mortality or survival <5 years. CONCLUSION: This study supports the hypothesis that the left internal mammary artery is smaller in Aboriginal patients compared to non-Aboriginal patients. Although Aboriginal patients were more likely to receive a venous conduit to the LAD, we observed no difference in survival up to 5 years. This data contrasts with reported outcomes of other ethnic groups.

Transcatheter mitral valve-in-valve: treatment of rheumatic heart disease in young patients.

BACKGROUND: Rheumatic heart disease (RHD) in young people presents a complex management problem. In Australia a significant proportion of those affected are Aboriginal and Torres Strait Islanders. Transcatheter mitral valve-in-valve (TMViV) replacement has emerged as an alternative to redo surgery in high-risk patients with degenerated mitral bioprostheses. The aim of this study is to review outcomes of TMViV replacement in young patients with RHD. METHODS: A single-centre, retrospective review of prospectively collected data on patients undergoing TMViV from December 2017 to June 2021. Primary outcome was major adverse cardiovascular events. Secondary outcome was post-operative trans-thoracic echocardiogram (TTE) results. RESULTS: There were seven patients with a mean age of 33 years and predominantly female (n = 5). Pre-operative comorbidities included diabetes (29%), chronic obstructive pulmonary disease (43%), left ventricular dysfunction (43%) and current smoking status (80%). Post-operative median length of hospital stay was 4 days with no post-operative renal failure, stroke, return to theatre, valve embolization or in hospital mortality. Post-operative TTE showed either nil or trivial central mitral regurgitation, no paravalvular leak and a median gradient of 5 mmHg (IQR 4.5, 7) across the new bioprosthesis; sustained at median follow-up of 22 months. CONCLUSION: Current literature of TMViV replacement is focused on an older population with concurrent comorbidities. This study provides a unique insight into TMViV replacement in a young cohort of patients with complex social and geographical factors which sometimes prohibits the use of a mechanical valve. The prevalence of RHD remains high for Aboriginal and Torres Strait Islanders, planning for future repeat valve operations should be considered from the outset. We consider TMViV as a part of a staged procedural journey for young patients with RHD.

Inferior vena cava filter limb embolization to the right ventricle: a case report.

Background: Inferior vena cava (IVC) filters are used to prevent pulmonary embolism (PE) in patients at a high risk for venous thromboembolism with a contraindication to anticoagulation. Inferior vena cava filters are associated with rare but significant long-term complications such as filter fracture and embolization. Case summary: We report the case of a 53-year-old female with an IVC filter inserted 8 years back for the management of recurrent bilateral PE resistant to anticoagulation. Imaging revealed an incidental finding of IVC filter limb fracture and migration to the right heart and the hepatic and renal veins. The patient remained asymptomatic with no impairment in cardiac, liver, or renal function. Due to a high operative risk, the broken IVC filter and embolized filter limbs were not retrieved. Discussion: There is no consensus on the management of intracardiac embolization of IVC filters. Intravascular fragments may be removed by endovascular or surgical approaches, depending on the anatomical location. Following IVC filter insertion, an appropriate follow-up must be put in place to ensure removal and limit clinical sequelae that are otherwise avoidable. A multidisciplinary approach to the management of IVC filter fracture and embolization is recommended.

Staged surgical repair of severe pulmonary stenosis post radiofrequency ablation.

We present a case of a 68-year-old man who presents with worsening cough and dyspnoea 12 months after undergoing radiofrequency ablation therapy for atrial fibrillation. Investigation revealed complete occlusion of the left lower pulmonary vein and partial stenosis of the left upper pulmonary vein. He underwent a stage surgical resection with the first stage being a left lower lobectomy for the non-viable lobe followed by a repair of the left upper pulmonary vein via anastomosis with the left atrial appendage. This staged procedure yielded excellent results and avoided the need for a left-sided pneumonectomy.

Early diagnosis of surgically curable lung cancer is commonly serendipitous.

AIMS: Lung cancer is the largest cause of cancer death in New Zealand, accounting for 18.3% of cancer-related deaths.[[1,2]] There is limited literature on how patients with lung cancer clinically present in New Zealand. The aim of this cohort study was to identify the rate of incidentally diagnosed lung cancer in the Midland Region, the common symptomatology and route of diagnosis. METHODS: This retrospective cohort study included patients with lung cancer who underwent potentially curative thoracic surgery between January 2011 to June 2018 at Waikato Hospital, New Zealand. Symptoms or signs recorded were cough, dyspnoea, haemoptysis, lymphadenopathy, chest pain, hoarseness, fatigue, weight loss and finger clubbing. The lung cancer cases were grouped into incidental finding, symptomatic general practitioner, symptomatic emergency department and surveillance. RESULTS: Three hundred and ten patients with lung cancer had thoracic surgery with curative intent at Waikato Hospital. Two hundred and fourteen (69%) patients had symptoms which prompted presentation to a treating physician and 96 (31%) patients were asymptomatic. Incidental diagnosis was demonstrated in 121 (39.4%) patients. Of the patients diagnosed incidentally, 36.4% (n=44) had symptoms of lung cancer with the main symptoms including 45% with cough (n=20), 28% with dyspnoea (n=12) and 28% chest pain (n=12). CONCLUSIONS: In New Zealand, a large amount of lung cancer is still diagnosed incidentally with symptoms of cough, dyspnoea and chest pain. Further research into the development of a lung cancer screening program in New Zealand for a high-risk population is warranted.

Ruxolitinib withdrawal complicating emergency aortic root replacement.

Ruxolitinib, a Janus kinase inhibitor, is associated with severe withdrawal phenomena. Adequate tapering is often underemphasized in surgical emergencies and can complicate the postoperative course. We present a case of acute ruxolitinib withdrawal in a gentleman undergoing emergency cardiac surgery.

Development of an organ procurement team in South Australia in response to COVID-19.

BACKGROUND: Due to the nature of border closures and quarantine requirements in Australia during the COVID-19 pandemic, the feasibility of interstate travel for organ retrieval created complex logistics. An organ procurement service in South Australia, to procure heart and lungs of local donors, was commenced to mitigate the impact of the travel restrictions imposed due to COVID-19. The purpose of this review was to examine the initial data and feasibility of the service. METHODS: A single unit, multi-site retrospective review from April 2020-August 2021 of all organ retrievals undertaken by the Flinders Medical Centre cardiothoracic service across Adelaide metropolitan area. Data was prospectively collected and analysed from the DonateLife South Australian centralized database. All data was de identified. RESULTS: A total of 25 organ procurements had been undertaken across 17 months since commencing the program. Total of 9 hearts and 16 bilateral lungs were procured with median age of donor of hearts 49 years (IQR 35.5-51. 5) and 60 years (IQR 44-72) for lung donation. Six organs were donated after determination of circulatory death and 19 after neurological determination of death. Median ischaemic time for heart donation was 4.4 h (IQR 3.0-5.8) and lung donation 4.4 h (IQR 3.4-6.1). All organs procured by the local South Australian team were successfully transplanted at the recipient site. Recipient sites included 8 in Victoria, 10 in New South Wales, 4 in Western Australia and 3 in Queensland. CONCLUSIONS: The necessity of flexibility within the field of cardiothoracic surgery is evident during the COVID-19 pandemic. The implementation of an organ retrieval service in South Australia has been successful with no apparent increased risk to successful transplant outcomes.

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.

Preoperative Neutrophil and Lymphocyte Ratio as a Predictor of Mortality and Morbidity After Cardiac Surgery.

BACKGROUND: Inflammatory markers, such as neutrophils and lymphocytes, for risk stratification of postoperative morbidity and mortality in patients with cardiovascular disease may provide benefit for patient selection for cardiac surgery. This study aimed to investigate the association between preoperative neutrophil to leucocyte ratio (NLR) after cardiac surgery. METHODS: A retrospective study from September 2014 to November 2017 undergoing cardiac surgery at Waikato Hospital was conducted. Preoperative haematological profiles, patient factors and primary and secondary endpoints were obtained. The primary endpoint was 30-day new postoperative atrial fibrillation requiring treatment, new neurological insult, readmission within 30 days and 30-day mortality. The secondary endpoint was long-term all cause mortality. RESULTS: Of the 1,694 patients included in the study, 21% (356/1,694) of patients had new atrial fibrillation (AF), 3.0% (51/1,694) strokes, 10.6% (180/1,694) readmissions and 2.8% (47/1,694) deaths within 30 days were observed. Receiver operator curve (ROC) returned a cut-off value of NLR equal to or greater than 3.23 (high NLR) to be associated with greatest mortality. Subsequently, a high NLR was compared to the endpoints. High NLR was associated with higher postoperative (p<0.001) and discharge creatinine, longer ICU stay (p=0.012), prolonged intubation and ventilation (p<0.001), new neurological status (p=0.002) and increased risk of returning to theatre (p=0.009). After logistic regression, high NLR was associated with increased mortality (OR 3.36, p=0.001). CONCLUSIONS: The interpretation and utilisation of readily available haematological markers can provide further risk stratification data to the surgeon when considering the postoperative cardiac surgery risks.

Operative Results of Mitral Valve Repair and Replacement in Chronic Ischaemic Mitral Valve Regurgitation.

BACKGROUND: Ischaemic mitral regurgitation (IMR) carries significant morbidity and mortality. Surgical management includes coronary artery bypass surgery alone or concomitant with mitral valve repair or replacement. There is ongoing debate regarding the appropriate approach to the mitral valve in relation to long-term outcomes. This review examines our early and late follow-up, with operative and echocardiographic outcomes for mitral valve repair and mitral replacement for chronic IMR. METHODS: A retrospective review was performed on prospectively collected data of 119 consecutive patients who either underwent mitral repair (n=101) or mitral replacement (n=18) for chronic IMR at Prince Henry and The Prince of Wales hospitals in Sydney between 1999-2016. All patients had pre and postoperative transthoracic echocardiograms. Follow-up echocardiographic data was obtained from the most recent clinical appointment. Follow-up mortality outcomes were obtained with ethics approval from the Australian National Death Index (NDI). RESULTS: There was no statistical difference between cardiopulmonary bypass (CPB) time, cross-clamp time, time spent in intensive care unit (ICU) and time to discharge between cohorts. The replacement cohort was noted to have higher preoperative pulmonary artery (PA) pressures and a higher severity of IMR. Seven (7) deaths were in the mitral valve (MV) repair group within 30 days (6.9%) and three deaths in the MV replacement group within 30 days (16.7%). Echocardiographic follow-up was complete in 78% of the MV repair cohort at an average of 4.06±2.66 years, and 73% complete in the MV replacement cohort at an average of 6.09±4.3 years. Three (3) patients had prior MV repair before MV replacement early at days zero and 17, and late at 8 years respectively. Follow-up echocardiography showed mitral regurgitation (MR) in the mitral valve repair cohort as ≤ mild in 83.5% and ≤ trivial in 35.6%. In the MV replacement cohort MR ≤ mild in 100% and ≤ trivial in 82% with no moderate or severe MR. Preoperative tricuspid regurgitation (TR) and a flexible annuloplasty were predictive of an MR grade > mild in the repair cohort at discharge. Five-year (5-year) survival for the repair cohort was 85% with a mean follow-up time of 7.1±3.83 years. For the replacement cohort, five-year survival was 77.8% with a mean follow-up time of 5.35±1.54 years. CONCLUSIONS: Mitral valve repair and replacement for chronic IMR has acceptable mortality, reintervention rates and excellent postoperative echocardiographic degrees of IMR in this cohort. Further evaluation is required into quality of life post intervention for IMR and of preoperative predictive factors of significant MR postoperatively to help guide the appropriate choice of treatment. The presence of preoperative tricuspid regurgitation of moderate grade or higher, and the use of a flexible annuloplasty may indicate patients more likely to have a higher grade of MR at follow-up following mitral valve repair in patients with IMR.

Acute shortness of breath due to reoccurrence of an intrapericardial bronchogenic cyst.

A 71-year-old woman presented with dysphagia and acute shortness of breath. Surgical history included a prior thoracotomy overseas for a bronchogenic mesothelial cyst 19 years before. Computed tomography demonstrated a mass within the posterior mediastinum measuring 69 × 70 × 74 mm. A median sternotomy was performed, and after removal of the cyst, repair of the left atrium and pulmonary vessels was undertaken due to the invading nature of the cyst. Intrapericardial bronchogenic cysts are a rare form of congenital cysts arising from the primitive foregut. The cardiac primordia are in close proximity to the foregut and primitive tracheobronchial tree, and thus, abnormal budding of the tracheobronchial tree can arise in a myocardial location. Irrespective of the method of approach in redo surgery, complete resection must be performed in order to minimize the chance of recurrence, relieve symptoms, eliminate risk of infection, and prevent malignant degeneration.