Acute Type A aortic dissection remains one of the most challenging conditions in aortic surgery. Despite the advancements in the field the mortality rate still remains high. Though there is a general consensus that the ascending aorta... more
Acute Type A aortic dissection remains one of the most challenging conditions in aortic surgery. Despite the advancements in the field the mortality rate still remains high. Though there is a general consensus that the ascending aorta should be replaced, the distal extension of the surgery still remains a controversy. Few surgeons argue for a conservative approach to reduce operative and postoperative morbidity while others considering the problems associated with "downstream problems" support an aggressive approach including a frozen elephant trunk. The cohort in the Indian subcontinent and APAC is far different from the western world. Many factors determine the decision for surgery apart from the pathology of the disease. Economy, availability of the suitable prosthesis, the experience of the surgeon, ease of access to the medical facility all contribute to the decision making to treat acute type A dissection.
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150 consecutive patients attending an anesthetics review for planned cardiac surgery underwent a haematinic screen. Anaemia was defined as a haemoglobin below 115g/l in females and below 130g/l in males. Iron deficiency was defined as a... more
150 consecutive patients attending an anesthetics review for planned cardiac surgery underwent a haematinic screen. Anaemia was defined as a haemoglobin below 115g/l in females and below 130g/l in males. Iron deficiency was defined as a ferritin below 11 μg/l in females and below 24 μg/l in males in the absence of raised inflammatory markers CRP and ESR. Intervention was implemented where possible to correct iron deficiency with or without anaemia. Intra-operative and post operative transfusion data was completed for 90% of patients over a 12 month period from July 2010 to July 2011. Chi square tests were used to compare transfusion rates between patient groups.
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BACKGROUND The aim of this study is to review our experience with using more than 2,000 RAs over the last seven years, and to assess the medium-term outcome in terms of morbidity and mortality. METHODS Between June 1994 and June 2001, a... more
BACKGROUND The aim of this study is to review our experience with using more than 2,000 RAs over the last seven years, and to assess the medium-term outcome in terms of morbidity and mortality. METHODS Between June 1994 and June 2001, a total of 2,024 RAs have been used in 1,613 patients. The mean duration of follow-up was 40.1 months and ranged from one to 88 months. We assessed the results of postoperative mortality and morbidity, RA graft patency, coronary event free rate, and actuarial survival rate. Specifically, the independent predictors of early and late mortalities were examined. RESULTS Perioperative myocardial infarction was indicated in 0.8%, stroke in 1.6%, respectively. Overall hospital mortality was 35 patients (2.4%). RA patency rate was 98.1%. Coronary event free rate and actuarial survival rates at seven years were 99.6% and 95.1%, respectively. Multivariate logistic regression analysis detected an ejection fraction of less than 30% (p=0.0009), re-exploration (p=0....
Research Interests: Risk Analysis, Humans, Female, Male, Key words, and 15 moreLogistic Regression Analysis, Aged, Middle Aged, Coronary Bypass Surgery, Adult, Retrospective Studies, Cabg, Perioperative myocardial infarction, Ejection Fraction, Hospital Mortality, Coronary artery bypass surgery, Logistic Models, Radial Artery, Cardiovascular medicine and haematology, and Coronary Artery Bypass
SARS CoV‐2 (COVID 19) is having a deep and lasting impact around the world. We review the effect it has had on our cardiothoracic surgery practice in Australia and give insights into our contingency planning, restructuring, practice... more
SARS CoV‐2 (COVID 19) is having a deep and lasting impact around the world. We review the effect it has had on our cardiothoracic surgery practice in Australia and give insights into our contingency planning, restructuring, practice changes, and the effect on our patients in this evolving pandemic.
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Aortic dissection is a complex condition with high morbidity and mortality. Endovascular treatments including percutaneous fenestration can be used to manage branch vessel ischaemia or risk of aortic rupture. A variety of techniques for... more
Aortic dissection is a complex condition with high morbidity and mortality. Endovascular treatments including percutaneous fenestration can be used to manage branch vessel ischaemia or risk of aortic rupture. A variety of techniques for aortic fenestration have been described. We describe the novel use of the TruePath Chronic Total Occlusion (CTO) device for aortic intimal fenestration to achieve side branch reconnection. We present three cases of aortic dissection presenting with symptoms of aortic side branch occlusion and end organ malperfusion, treated with aortic fenestration using the TruePath CTO device via trans-brachial and trans-femoral approaches. Technical success was achieved in all three cases. No complications were encountered. Flow was restored in compromised visceral branches. Branches remained patent on follow-up CT angiography over a minimum 2.5-year follow-up period. Percutaneous aortic fenestration techniques enable a minimally invasive approach to treat visceral branch malperfusion associated with aortic dissection. The TruePath CTO device improves the control of the fenestration procedure with the potential to improve efficacy and safety.
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Intravenous magnesium is routinely administered in intensive care units (ICU) to treat arrhythmias after cardiothoracic surgery. There are no data on the pharmacokinetics of continuous magnesium infusion therapy. To investigate the... more
Intravenous magnesium is routinely administered in intensive care units (ICU) to treat arrhythmias after cardiothoracic surgery. There are no data on the pharmacokinetics of continuous magnesium infusion therapy. To investigate the pharmacokinetics of continuous magnesium infusion, focusing on serum and urinary magnesium concentration, volume of distribution and half-life. We administered a 10 mmol bolus of magnesium-sulfate followed by a continuous infusion of 3 mmol/h for 12 h in twenty cardiac surgery patients. We obtained blood and urine samples prior to magnesium administration and after one, six, and 12 h. Median magnesium levels increased from 1.09 (IQR 1.00-1.23) mmol/L to 1.59 (1.45-1.76) mmol/L after 60 min (p < .001), followed by 1.53 (1.48-1.71) and 1.59 (1.48-1.76) mmol/L after 6 and 12 h. Urinary magnesium concentration increased from 9.2 (5.0-13.9) mmol/L to 17 (13.6-21.6) mmol/L after 60 min (p < .001). Cumulative urinary magnesium excretion was 28 mmol (60.9% ...
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The predictors and independent outcome association of delirium after cardiac surgery are important and yet poorly characterised. We performed a retrospective observational study of cardiac surgery patients between January 2009 and March... more
The predictors and independent outcome association of delirium after cardiac surgery are important and yet poorly characterised. We performed a retrospective observational study of cardiac surgery patients between January 2009 and March 2016. We defined delirium using ICD-10 diagnostic codes. Multivariable analysis was conducted to find independent associations between baseline variables, delirium, and key clinical outcomes. We studied 2447 study patients (28.7% female, median age was 66 [IQR 57-74] years). Delirium was coded for in 12.9% of patients overall, and in 22.9% of those aged >75years. Increasing age, Charlson co-morbidity index, admission not from home, peripheral vascular disease, respiratory disease, preoperative atrial fibrillation, duration of cardiopulmonary bypass and nature of surgery were all independent predictors of delirium. Delirium was independently and strongly associated with increased risk of reintubation (OR 8.18 [95% CI 5.24-12.78]), tracheostomy (OR ...
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Total aortic arch replacement (TOTAL) is a complicated operation and has traditionally required deep hypothermic circulatory arrest. In this study, the impact of moderate hypothermic circulatory arrest (MHCA) and antegrade cerebral... more
Total aortic arch replacement (TOTAL) is a complicated operation and has traditionally required deep hypothermic circulatory arrest. In this study, the impact of moderate hypothermic circulatory arrest (MHCA) and antegrade cerebral perfusion (ACP) for TOTAL were examined. The ARCH International aortic database was queried and 3,265 patients undergoing TOTAL using ACP were identified. Patients were divided into groups based on lowest cooling temperature: MHCA (20° to 28°C) or deep hypothermia (DHCA) (12° to 20°C). Propensity-matched scoring using 15 variables was used in 669 matched pairs. Multivariable analyses were performed. In the unmatched cohort, more patients underwent MHCA (2,586; 79.2%) who were also younger (p < 0.001) and more frequently underwent emergent operations (p < 0.001) than DHCA patients. For the propensity-matched patients, there were significant differences in cardiopulmonary bypass (CPB) time (MHCA 200 minutes versus DHCA 243 minutes, p < 0.001), aort...
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To investigate the pharmacokinetics of a 20 mmol magnesium bolus in regards to serum and urinary magnesium concentration, volume of distribution, and half-life. Prospective, experimental study. A university-affiliated teaching hospital.... more
To investigate the pharmacokinetics of a 20 mmol magnesium bolus in regards to serum and urinary magnesium concentration, volume of distribution, and half-life. Prospective, experimental study. A university-affiliated teaching hospital. Twenty consecutive cardiac surgery patients treated with magnesium bolus therapy for prevention of arrhythmia. A 20-mmol bolus of magnesium sulfate was administered intravenously. Median magnesium levels increased from 1.04 (interquartile range 0.94-1.23) mmol/L to 1.72 (1.57-2.14) mmol/L after 60 minutes of magnesium infusion (p &lt; 0.001) but decreased to 1.27 (1.21-1.36) and 1.16 (1.11-1.21) mmol/L after 6 and 12 hours, respectively. Urinary magnesium concentration increased from 6.3 (4.2-14.5) mmol/L to 19.1 (7.4-34.5) mmol/L after 60 minutes (p &lt; 0.001), followed by 22.7 (18.4-36.7) and 15 (8.4-19.7) mmol/L after 6 and 12 hours, respectively. Over the 12-hour observation period, the cumulative urinary magnesium excretion was 19.1 mmol (95.5% of the dose given). The median magnesium clearance was 10 (4.7-15.8) mL/min and increased to 14.9 (3.8-20.7; p = 0.934) mL/min at 60 minutes. The estimated volume of distribution was 0.31 (0.28-0.34) L/kg. Magnesium bolus therapy after cardiac surgery leads to a significant but short-lived increase of magnesium serum concentration due to renal excretion and distribution, and the magnesium balance is neutral after 12 hours.
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Implantable cardioverter-defibrillator (ICD) and cardiac resynchronisation therapy (CRT) is generally limited to transvenous techniques especially in pacing-dependant patients. We describe a novel case in which an epicardial CRT-D system... more
Implantable cardioverter-defibrillator (ICD) and cardiac resynchronisation therapy (CRT) is generally limited to transvenous techniques especially in pacing-dependant patients. We describe a novel case in which an epicardial CRT-D system was successfully implanted with a two-year follow-up in a pacing-dependant patient.
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To compare the physiology of apneic oxygenation with low-tidal-volume (VT) ventilation during harvesting of the left internal mammary artery. Prospective, single-center, randomized trial. Single-center teaching hospital. The study... more
To compare the physiology of apneic oxygenation with low-tidal-volume (VT) ventilation during harvesting of the left internal mammary artery. Prospective, single-center, randomized trial. Single-center teaching hospital. The study comprised 24 patients who underwent elective coronary artery bypass grafting surgery. Apneic oxygenation (apneic group: 12 participants) and low-VT ventilation (low-VT group: 12 participants) (2.5 mL/kg ideal body weight) for 15 minutes during harvesting of the left internal mammary artery. The primary endpoint was an absolute change in partial pressure of arterial carbon dioxide (PaCO2). Secondary endpoints were changes in arterial pH, pulmonary artery pressures (PAP), cardiac index, and pulmonary artery acceleration time and ease of surgical access. The mean (standard deviation) absolute increase in PaCO2 was 31.8 mmHg (7.6) in the apneic group and 17.6 mmHg (8.2) in the low-VT group (baseline-adjusted difference 14.2 mmHg [95% confidence interval 21.0-7...
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The surgical management of acute type A aortic dissection (ATAAD) is in a period of rapid evolution. Understanding the complex physiology and anatomy of both acute and chronic dissection has been enhanced by the ready availability of... more
The surgical management of acute type A aortic dissection (ATAAD) is in a period of rapid evolution. Understanding the complex physiology and anatomy of both acute and chronic dissection has been enhanced by the ready availability of state of the art imaging techniques. Technical advances in the intraoperative monitoring of organ perfusion, together with adjuncts to limit organ injury and increasing sophistication in open and endovascular surgery have led to a major reduction in both perioperative morbidity and mortality. In many centers, there has been a transition in mindset and surgical approach away from a purely central aortic operation focusing on the ascending aorta and a 'live to fight another day' philosophy. The current more global perspective recognizes the importance of aortic valve function, malperfusion, false lumen (FL) patency and the potential for future complex aneurysm development. The time is now right to transition into the next phase of sophistication i...
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Acute type A dissection (ATAAD) remains a morbid condition with reported surgical mortality as high as 25%. We describe our surgical approach to ATAAD and discuss the indications for adjunct techniques such as the frozen elephant trunk or... more
Acute type A dissection (ATAAD) remains a morbid condition with reported surgical mortality as high as 25%. We describe our surgical approach to ATAAD and discuss the indications for adjunct techniques such as the frozen elephant trunk or complete aortic repair with endovascular methods. Arch replacement using the "branch-first technique" allows for complete root, ascending aorta, and arch replacement. A long landing zone is created for proximal endografting with a covered stent. Balloon-assisted intimal disruption and bare metal stenting of all residual dissected aorta to the level of the aortic bifurcation is then performed to obliterate the false lumen (FL) and achieve single true lumen (TL) flow. Additional branch vessel stenting is performed as required.
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Carotid endarterectomy is a controversial procedure. Despite the increasing incidence of its performance, there have been as yet no prospective randomised trials which have conclusively shown its benefits for patients with carotid artery... more
Carotid endarterectomy is a controversial procedure. Despite the increasing incidence of its performance, there have been as yet no prospective randomised trials which have conclusively shown its benefits for patients with carotid artery atherosclerosis. Until the results of such studies become available, a rational approach to the estimation of stroke risk in these patients can be based on an understanding of their carotid plaque morphology. Over the past 4 years we have examined plaque morphology with a B-mode duplex scanner and have been able to categorise the degree of heterogeneity of plaques into 4 types depending on the degree of plaque echolucency. We have shown good correlation between the preoperative plaque type and the operation specimen. Furthermore, we have found that the risk of symptom development correlates with the development of a more echolucent plaque. Finally, while plaque heterogeneity may be a good predictor of the risk of embolism from the plaque, other dele...
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Despite renewed clinical interest in radial artery grafts (RA) for coronary artery bypass grafting, there is a paucity of controlled prospective data on its efficacy. We report on the rate of harvest related complications from a... more
Despite renewed clinical interest in radial artery grafts (RA) for coronary artery bypass grafting, there is a paucity of controlled prospective data on its efficacy. We report on the rate of harvest related complications from a randomized radial artery study. Two hundred eighty nine patients were divided into two groups. Group 1 received RA grafts (n=154 patients) and Group 2 (n=135 patients) received saphenous vein grafts (SVG). Postoperative wound problems were assessed using a questionnaire. Postoperative harvest site infections were also carefully documented. In group 1, 6 of 154 (3.9%) patients had harvest site wound infections. Five of them improved by antibiotic therapy alone. In group 2, 24 of 135 (17.8%) patients had harvest site wound infections (p=0.001 vs. group 1). Fifteen of these patients needed redressing due to discharge from the wound. One hundred forty-nine patients (96.7%) in group 1 answered that their hand function was normal on the questionnaire. Concerns and...
Research Interests: Australia, Treatment Outcome, Medicine, Humans, Female, and 15 moreMale, Follow-up studies, Patient Satisfaction, Body Mass Index, Aged, Prevalence, Middle Aged, Leg, SAPHENOUS VEIN, Coronary artery bypass surgery, Forearm, Radial Artery, Surgical wound infection, Cardiovascular medicine and haematology, and Coronary Artery Bypass
The aim of this study is to review our experience with using more than 2,000 RAs over the last seven years, and to assess the medium-term outcome in terms of morbidity and mortality. Between June 1994 and June 2001, a total of 2,024 RAs... more
The aim of this study is to review our experience with using more than 2,000 RAs over the last seven years, and to assess the medium-term outcome in terms of morbidity and mortality. Between June 1994 and June 2001, a total of 2,024 RAs have been used in 1,613 patients. The mean duration of follow-up was 40.1 months and ranged from one to 88 months. We assessed the results of postoperative mortality and morbidity, RA graft patency, coronary event free rate, and actuarial survival rate. Specifically, the independent predictors of early and late mortalities were examined. Perioperative myocardial infarction was indicated in 0.8%, stroke in 1.6%, respectively. Overall hospital mortality was 35 patients (2.4%). RA patency rate was 98.1%. Coronary event free rate and actuarial survival rates at seven years were 99.6% and 95.1%, respectively. Multivariate logistic regression analysis detected an ejection fraction of less than 30% (p=0.0009), re-exploration (p=0.02), and stroke (p=0.03) as...
Research Interests: Risk Analysis, Humans, Female, Male, Risk factors, and 15 moreLogistic Regression Analysis, Aged, Middle Aged, Coronary Bypass Surgery, Adult, Retrospective Studies, Risk Factors, Perioperative myocardial infarction, Ejection Fraction, Hospital Mortality, Coronary artery bypass surgery, Logistic Models, Radial Artery, Cardiovascular medicine and haematology, and Coronary Artery Bypass
Despite theoretical advantages of antegrade (ACP) and retrograde cerebral perfusion (RCP) in addition to deep hypothermic arrest (DHA) in aortic arch surgery, there is still controversy about the best method of cerebral protection. We... more
Despite theoretical advantages of antegrade (ACP) and retrograde cerebral perfusion (RCP) in addition to deep hypothermic arrest (DHA) in aortic arch surgery, there is still controversy about the best method of cerebral protection. We reviewed our experience with neurological outcome after aortic arch repair over the last five years. Sixty-two patients undergoing aortic arch repair were reviewed. Five patients (8.1%) had Marfan's syndrome, 11 (17.7%) had previous cardiac operations, and 13 (21.0%) also received coronary bypass grafting (CABG). The extent of arch replacement was proximal level in 40 (64.5%), distal level in 18 (29.0%), and total in 13 (21.0%). The method of cerebral protection was DHA alone in 14 patients, DHA with RCP in 23, and DHA with ACP in 25. Pre-, intra-, and postoperative variables in the three categories of cerebral protection were compared. Specifically, the independent predictors of mortality, stroke, and temporary neurological dysfunction (TND) were ...
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Recent studies have suggested that increased left ventricular (LV) size is a risk factor for perioperative mortality in patients with low ejection fraction (EF) undergoing coronary artery bypass surgery (CABG). We previously presented a... more
Recent studies have suggested that increased left ventricular (LV) size is a risk factor for perioperative mortality in patients with low ejection fraction (EF) undergoing coronary artery bypass surgery (CABG). We previously presented a new method of LV reconstruction, called geometric endoventricular repair (GER) as representing a physiologically effective repair. The aim of this study is to assess whether GER confers benefits compared to patients undergoing CABG alone. Between July 1996 and July 2001, 110 patients with a low EF of less than 35% documented by radionuclide ventriculogram (RNVG) underwent CABG in Austin Hospital, Australia, and were divided into two groups. Group I consisted of 52 patients undergoing isolated CABG. Group II comprised 58 patients undergoing CABG and GER. We compared the two groups in terms of EF, NYHA class, incidence of recurrent heart failure, and mortality. Preoperative EF was 27.7+/-6.1% in group I and 27.4+/-5.7% in group II, respectively (NS), w...
Research Interests: Treatment Outcome, Medicine, Heart Failure, Humans, Left Ventricular Assist Device, and 15 moreFollow-up studies, Risk factors, Left Ventricular Dysfunction, Aged, Middle Aged, Time Factors, Survival Rate, Risk Factors, Ejection Fraction, Coronary artery bypass surgery, Heart Ventricles, Myocardial Ischemia, Left Ventricular, Cardiovascular medicine and haematology, and Coronary Artery Bypass
As the cause of allograft heart valve degeneration is poorly understood, the study aim was to investigate the host antibody response to allograft valve implantation. Sera were obtained from 92 recipients of allograft heart valves (61... more
As the cause of allograft heart valve degeneration is poorly understood, the study aim was to investigate the host antibody response to allograft valve implantation. Sera were obtained from 92 recipients of allograft heart valves (61 pulmonary, 31 aortic). Sera were tested for anti-HLA class I antibodies by ELISA and complement-dependent cytotoxicity (CDC) methods, and anti-HLA class II antibodies by ELISA. Specificities of recipient anti-HLA class I antibodies were defined by standard CDC testing against a panel of T lymphocytes from 80 blood donors. Donor valve HLA typing was performed on stored donor DNA samples using molecular methods. The presence of donor-specific anti-HLA class I antibodies was hence defined in recipient sera. The presence of anti-HLA antibodies and donor-specific anti-HLA class I antibodies were correlated with function of allograft valves at the most recent echocardiographic follow up. At a mean of 3.0 years (range: 0.3-5.4 years) after allograft implantati...
Research Interests: Cryopreservation, Adolescent, Antibodies, Humans, Female, and 14 moreMale, Follow-up studies, Organ Preservation, Cadaver, Aged, Middle Aged, Heart valves, Adult, Time Factors, Cross Sectional Studies, The Heart, Heart Valve Prosthesis Implantation, Heart valve disease, and Cardiovascular medicine and haematology
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Acute type A aortic dissection (TAAD) remains a morbid condition; although overall outcomes have improved, patients presenting with preoperative malperfusion syndromes continue to have excessive mortality following conventional open... more
Acute type A aortic dissection (TAAD) remains a morbid condition; although overall outcomes have improved, patients presenting with preoperative malperfusion syndromes continue to have excessive mortality following conventional open surgical repair. Mesenteric malperfusion is generally associated with the worst prognosis and postoperative mortality in this group. With advances in the endovascular treatment of aortic pathology, options now exist to percutaneously manage mesenteric malperfusion prior to central aortic repair. This strategy may be associated with improved outcomes. To review this, a best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was 'In patients with acute type A aortic dissections with mesenteric malperfusion, does management of the malperfusion prior to central aortic repair reduce perioperative mortality'. Overall, more than 309 papers were found as a result of the reported search, of which 11 re...
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Redo-sternotomy and aortic valve replacement in patients with advanced liver disease is rare and associated with a prohibitive morbidity and mortality. Refractory coagulopathy is common and a consequence of intense activation of the... more
Redo-sternotomy and aortic valve replacement in patients with advanced liver disease is rare and associated with a prohibitive morbidity and mortality. Refractory coagulopathy is common and a consequence of intense activation of the coagulation system that can be triggered by contact of blood with the cardiopulmonary bypass circuitry, bypass-induced fibrinolysis, platelet activation and dysfunction, haemodilution, surgical trauma, hepatic decompensation and hypothermia. Management can be further complicated by right heart dysfunction, porto-pulmonary hypertension, poor myocardial protection, and hepato-renal syndrome. Complex interactions between coagulation/fibrinolysis and systemic inflammatory response syndrome reactions like "post-perfusion-syndrome" also compound haemostatic failure. Given the limited information available for the specific management and prevention of cardiopulmonary bypass-induced haemostatic failure, this report serves to guide the anaesthesia and m...
The radial artery (RA) is often selected as the next conduit of choice following the internal thoracic artery for coronary artery bypass grafting operations (CABG). Radial access coronary angiography (RA-CA) has grown in popularity among... more
The radial artery (RA) is often selected as the next conduit of choice following the internal thoracic artery for coronary artery bypass grafting operations (CABG). Radial access coronary angiography (RA-CA) has grown in popularity among cardiologists and has been advocated as the access route of choice for coronary angiography and intervention by many groups. However, sheath insertion and instrumentation may lead to structural and functional damage to the RA, which may preclude its use as a bypass conduit. The increasing use of RA-CA may therefore have an adverse effect on the ability to use the RA as a bypass conduit at subsequent CABG. To review this, a best evidence topic in cardiothoracic surgery was written according to a structured protocol. The question addressed was: 'should the radial artery be used as a bypass conduit following radial access coronary angiography'? Altogether, 167 papers were found using the reported search; 11 papers were identified that provided ...
Research Interests: Evidence Based Medicine, Treatment Outcome, Benchmarking, Humans, Female, and 15 moreMale, Hyperplasia, Risk factors, Middle Aged, Coronary Angiography, Time Factors, Internal medicine Doppler ultrasonography, Risk Factors, Coronary Artery Disease, Coronary artery bypass surgery, Predictive value of tests, Neointima, Radial Artery, Patient selection, and Coronary Artery Bypass
Platypnea-orthodeoxia describes the condition of combined dyspnea and hypoxia respectively, whilst in the upright position, which improves in the recumbent position. We present a case of platypnea-orthodeoxia due to a fenestrated atrial... more
Platypnea-orthodeoxia describes the condition of combined dyspnea and hypoxia respectively, whilst in the upright position, which improves in the recumbent position. We present a case of platypnea-orthodeoxia due to a fenestrated atrial septal defect associated with an atrial septal aneurysm. Due to the fenestrated nature of the atrial septal defect, surgical rather than percutaneous correction was performed. A high index of suspicion is required to diagnose the syndrome of platypnea-orthodeoxia. Careful echocardiographic evaluation is required to identify the syndrome, and to determine suitability for percutaneous repair.
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The causes of cryopreserved allograft heart valve degeneration are poorly understood. We investigated HLA mismatch and other factors implicated in allograft valve degeneration. For this study we recruited 110 adult recipients of allograft... more
The causes of cryopreserved allograft heart valve degeneration are poorly understood. We investigated HLA mismatch and other factors implicated in allograft valve degeneration. For this study we recruited 110 adult recipients of allograft heart valves who underwent surgery between June 1998 and March 2003 in the state of Victoria, Australia. Recipients and donors were HLA typed using serological and molecular methods. Valve function at most recent echocardiographic follow-up was examined for an association with the following variables using univariate and multivariate methods: HLA-A,-B, and -DR donor-recipient mismatch; HLA class I mismatch; total HLA mismatch; valve ischemic time; recipient age; donor age; ABO blood group donor-recipient match; and allograft size. Mean recipient age was 45 years (18-75 years), 75% were men. Seventy-four pulmonary (62 Ross procedure) and 36 aortic allografts were examined. Median valve ischemic time was 31 hours, range 20-48 hours. Echocardiographic follow-up was complete at a mean of 41 (+/-18) months, range 6-85 months. At univariate analysis longer ischemic time and younger recipient age were associated with valve dysfunction. HLA-A, -B, or DR mismatch, HLA class I mismatch, total HLA mismatch, donor age, ABO mismatch, and allograft size were not associated with valve dysfunction. Only younger recipient age remained significant at multivariate analysis. In conclusion, longer ischemic times and younger patient age predicted valve dysfunction at a mean of 3 years follow-up. Recipient age remained the strongest predictor of valve dysfunction. These results indicate that allograft ischemic times should be minimized.
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Monoclonal antibodies to epidermal antigens and cell surface carbohydrate markers, as defined by lectin binding, were used to analyze the cells in squamous and basal cell carcinomas of the skin (SCC and BCC). The cells in BCC failed to... more
Monoclonal antibodies to epidermal antigens and cell surface carbohydrate markers, as defined by lectin binding, were used to analyze the cells in squamous and basal cell carcinomas of the skin (SCC and BCC). The cells in BCC failed to stain with the lectin peanut agglutinin (PNA), which stains surface carbohydrates of cells in the stratum spinosum and stratum granulosum layers of normal epidermis, confirming histological observations that the cells in BCC are incapable of differentiation beyond the basal cell stage. Conversely, the central cells in SCC did react with PNA, suggesting that they can differentiate to a stage equivalent to the stratum spinosum of epidermis. The zone immediately surrounding BCC differed from that around SCC in lectin binding and staining with antisera to laminin and fibronectin, an observation which could be connected with the failure to metastasize. It was of interest that histologically normal skin immediately adjacent to and overlying these tumours showed marked changes in reaction with markers of normal epidermis. The outer layers of this epidermis showed aberrant retention of the lower molecular weight cytokeratins marked by the monoclonal antibodies LMM2 and LMM3, and occasional strong staining of individual cells by the stratum granulosum-reactive LMM1. These changes appear to be indicative of a &#39;premalignant&#39; state in these cells and the monoclonal antibodies are thus potentially useful reagents for early detection of skin malignancies.