Assessment of a goal-directed perfusion strategy through an oxygen delivery audit.

INTRODUCTION: Evidence supports the role of oxygen delivery (DO2) in ameliorating acute kidney injury (AKI). While instrumentation for continuous DO2 measurement exists, a simplified method has been reported for targeting a specific DO2 index (DO2i), commonly referred to as a goal-directed perfusion (GDP) strategy, by using a reference table and available data such as body surface area and continuous haematocrit values. This simplified approach can also be used for quality auditing via archived data. METHODS: This retrospective sequential audit was conducted to assess the impact of employing a GDP strategy within our institution by examining perfusion practices, DO2 levels and renal outcomes before and after implementation. A total of 246 patients undergoing elective primary coronary revascularisation were included: 125 patients in the pre-change group and 121 patients in the post-change group. A DO2i threshold above 280 mL/min/m2 was targeted in the post-GDP group. RESULTS: While both groups maintained a mean DO2 above the threshold, the post-GDP group exhibited a higher average DO2i (311 vs 291 mL/min/m2). The GDP strategy led to higher nadir DO2i (255 vs 225, p < .001) and was coupled with a reduction in the time below the 280 mL/min/m2 threshold (30 min vs 50 min, p < .001). The average cardiac index in the post-GDP group was higher (1.87 vs 1.65, p < .001) while also demonstrating a smaller creatinine rise of 6.8% compared to 13.5% in the control group (p = .035). There was no difference in AKI or mortality rates between the groups. CONCLUSION: The implementation of the GDP strategy demonstrated an enhancement in oxygen delivery during cardiopulmonary bypass, primarily attributable to elevated pump flow rates. A statistically significant decrease in serum creatinine levels was observed. The published reference table emerged as a simple yet effective tool in optimising our GDP strategy.

Is Transcatheter Aortic Valve Implantation (TAVI) Activity in Australia Consistent With International Guidelines?

BACKGROUND: Transcatheter aortic valve implantation (TAVI) did not receive regulatory approval in Australia until 2013, several years after Europe (2007) and America (2011). Consequently, the uptake of TAVI in Australia initially lagged behind international best practices. This study was undertaken to provide an update on the status of TAVI activity in Australia. METHOD: A descriptive population-level epidemiological study was performed. Annual activity data for both surgical aortic valve replacement (SAVR) and TAVI were obtained from the Australian Institute of Health and Welfare (AIHW) for the period from 1 July 2012 to 30 June 2022. Dynamic contemporaneous population data were obtained from the Australian Bureau of Statistics (ABS). Trends in absolute activity, population-adjusted activity and age cohort-adjusted activity were examined. RESULTS: Despite the impact of the COVID-19 pandemic on the Australian healthcare system, TAVI activity has continued to increase. Annual TAVI activity now exceeds annual SAVR activity (3,967 vs 3,870), albeit driven by TAVI in patients aged 85+ years. Population-adjusted TAVI activity now exceeds the reported European average (15.3 vs 14.1 per 100,000 persons). The point of equipoise for the choice between SAVR and TAVI is the 75-79 age cohort (50% vs 50%). CONCLUSIONS: Australian TAVI activity is now consistent with international best practice.

An Unusual Case of Cannula Obstruction Resulting from Venous Thromboembolism.

Cerebral strokes of unknown origin frequently present with a patent foramen ovale (PFO), a common atrial septal defect occurring in approximately 25% of the adult population. Deep vein thrombosis (DVT) or pulmonary embolism (PE) in the presence of a PFO can produce paradoxical systemic embolization subsequent to an increase in pulmonary pressure, permitting entry of thrombi into the arterial circulation. Diagnosis of an impending paradoxical embolism (IPDE) involves the detection of DVT or PE in the presence of an abnormal communication between left and right circulations and may include a right-to-left shunt. Treatment includes oral anticoagulation, antiplatelet agents, thrombolysis, transcatheter closure of the defect, or surgical embolectomy and PFO closure. As a result of risks of intracranial hemorrhage with fibrinolysis, pulmonary embolectomy using cardiopulmonary bypass (CPB) and deep hypothermia is a primary treatment with a surgical mortality rate at approximately 5%. Despite optimal management, IPDE is associated with a mortality rate of 18%. Prompt diagnosis and treatment is critical in avoiding systemic thromboembolization and strokes in these patients. We report a case of superior vena cava cannula obstruction resulting from a paradoxical embolus traversing a PFO during surgery. Warning signs and management during CPB are discussed.

Extracorporeal membrane oxygenation support in a situation of diagnostic dilemma.

Severe acute respiratory distress syndrome (ARDS) in children carries a high morbidity and mortality. High frequency ventilation and extracorporeal membrane oxygenation (ECMO) are used as rescue modes of support in difficult situations. Malignancy may be considered to be a relative contraindication to ECMO support. We report a case where the decision was made to support the patient with ECMO for fulminant Epstein-Barr (EBV) infection while investigations were being done to exclude an underlying malignancy.

Venoarterial Extracorporeal Membrane Oxygenation for Ruptured Sinus of Valsalva Aneurysm.

Sinus of Valsalva aneurysm rupture is a potentially fatal condition that requires urgent surgical intervention. We report a case of right sinus of Valsalva aneurysm rupture into the right atrium in a patient with a monocuspid aortic valve successfully managed with femoral venoarterial extracorporeal membrane oxygenation after pulseless electrical activity cardiac arrest to facilitate complete surgical repair. The patient made a full recovery and was discharged home with no neurologic deficit and had no limitations at the 1-year follow-up. This case highlights the utility of venoarterial extracorporeal membrane oxygenation in facilitating successful surgical repair when patients present in extremis.

Should cardiac surgery be delayed in patients with uncorrected hypothyroidism?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: 'should cardiac surgery be delayed in patients with uncorrected hypothyroidism?' A total of 1412 papers were found using the reported search, of which 7 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. There was limited high-quality evidence with the majority of the studies being retrospective. One propensity-matched analysis and 6 cohort studies provided the evidence that there was no significant difference in the rate of major adverse cardiac events including mortality based on thyroid status. However, hypothyroidism and subclinical hypothyroidism were associated with higher rates of postoperative atrial fibrillation. Based on the available evidence, we conclude that cardiac surgery should not be delayed to allow achievement of euthyroid status.

Traumatic pulmonary arteriovenous malformation presenting with massive hemoptysis 30 years after penetrating chest injury.

A 39-year-old man presented with massive hemoptysis requiring emergency double lumen endobronchial intubation, bronchial arteriography and embolization, and subsequent right lower lobectomy. He had suffered a shrapnel blast injury to the right chest as a 9-year-old boy. Pathology of the resected specimen revealed lodged metallic foreign body with traumatic arteriovenous malformation. We present this case to alert thoracic surgeons to this extremely rare clinical entity that can present itself many years after the penetrating trauma, which requires urgent surgery.

Impending paradoxical embolism: have we lost the clot?

Impending paradoxical embolism is a rare diagnosis that requires urgent treatment. We present a case where surgical thromboembolectomy was undertaken. The thrombus vanished from view on transesophageal ultrasound and was presumed to have undergone embolisation while bypass was established. Unexpectedly, it was found tangled in the superior vena cava cannula apertures.

One problem two issues! Left ventricular systolic and diastolic dysfunction in aortic stenosis.

Reports suggested that immediate post-aortic valve replacement (AVR); left ventricular (LV) dysfunction may be an important risk for morbidity and mortality in patients requiring positive inotropic support. Several factors have been identified as significant prognostic factors i.e., LV systolic dysfunction, LV diastolic dysfunction (LV-DD), heart failure and myocardial infarction (MI). Specific to pathophysiological changes associated with AS, markers of systolic LV function (e.g., LVEF) have been extensively studied in management, yet only a few studies have analysed the association between LV-DD and immediate post-operative LV dysfunction This review brings together the current body of evidence on this issue.

Idiopathic pulmonary trunk aneurysm causing airway obstruction in an infant.

We report a case of idiopathic pulmonary trunk aneurysm in an infant, in which the main clinical picture was airway obstruction. Aneurysmorraphy was the chosen surgical approach and showed to be successful on 13 months follow-up.

Outcomes following surgery for congenital heart disease in low-birthweight infants.

AIM: To describe cardiac surgery, survival and outcomes for low-birthweight (< or = 2500 g) infants undergoing surgery for congenital heart disease. METHODS: Using data from a prospectively collected population-based database of admissions to neonatal intensive care units in New South Wales and the Australian Capital Territory, we identified all low-birthweight infants undergoing cardiac surgery between 1992 and 2001. Infants with only a persistent ductus arteriosus were excluded. Two-year cardiac and neurodevelopmental outcome data were sought from hospital medical records. RESULTS: A total of 121 low-birthweight infants underwent cardiac surgery, of whom 34% had a congenital syndrome or non-cardiac birth defect. Most (81%) underwent a palliative surgical procedure in the neonatal period. There were 19 early (15.7%) and 19 late deaths giving a 2-year mortality of 31%. Factors associated with mortality included birthweight below 1500 g (P = 0.006), low weight at surgery (P = 0.028) and Apgar score at 1 min (P = 0.019). No single factor predicted 30-day mortality. By 2 years of age, 27 (33% of survivors) were known to have neurodevelopmental delay. Although 22 children are known to be developing normally, the neurodevelopmental status of 34 children was not known. CONCLUSIONS: These surgical data were comparable to previous single-institution studies. This group had a high risk of disability due to prematurity, low birthweight and associated conditions. There is a need to prospectively assess and manage neurodevelopmental outcomes in this group.

Synovial sarcoma of the heart.

We report a case of synovial sarcoma of the heart in a 14-year-old boy, who presented with signs of mild generalized illness and rapidly progressed to haemodynamic collapse. On operation the tumour was attached to the tricuspid valve, away from the atrioventricular node. He was considered to have incomplete resection due to extensive adhesions to the atrioventricular junction, and was offered chemotherapy. On 18 months follow-up, he was asymptomatic.

Levosimendan for patients with impaired left ventricular function undergoing cardiac surgery.

The efficacy of levosimendan treatment for a low cardiac output status following cardiac surgery has not been established. Here, we review our initial experiences of the perioperative use of levosimendan. This study is a retrospective uncontrolled trial. Nine patients who underwent cardiac surgery, and developed a low cardiac output status resistant to conventional inotropic support, were given levosimendan. The mean preoperative ejection fraction was 35.2+/-3.4%. All patients were on concomitant inotropic agents and had previously undergone intra-aortic balloon pumping. Cardiac index increased immediately from 2.14+/-0.33 l/min/m(2) at baseline to 2.41+/-0.31 (P=0.02) at 1 h, rising to 2.67+/-0.43 (P<0.001) at 4 h after the loading dose was started. Similarly, the systemic vascular resistance index decreased from 2350+/-525 dynes/s/cm(-5)/m(2) at baseline to 1774+/-360 (P=0.002) at 4 h. In the case of all but one of the patients, either the dose of the concomitant inotropic support or the balloon pumping could be weaned down within 24 h after completion of the levosimendan infusion. No withdrawal of levosimendan was required. Levosimendan could constitute a new therapeutic option for postoperative low cardiac output.

A simple system to deliver blood cardioplegia.

We describe a simple and inexpensive system designed to deliver blood cardioplegia either diluted or at the patient's hematocrit, with controlled temperature and additive concentration. This system can be applied to any pump set, and suits any strategy for clinical myocardial preservation.