Peter Laws - Academia.edu (original) (raw)

Papers by Peter Laws

European Journal of Vascular and Endovascular Surgery, 2013

To document the treatment of all patients with infected aortic grafts at Christchurch Hospital be... more To document the treatment of all patients with infected aortic grafts at Christchurch Hospital between 1999 and 2010, focussing on the mortality and morbidity of those treated without graft explantation. Cases of infected aortic grafts were reviewed. Cases required a compatible clinical syndrome, CT imaging and tissue/blood culture results. Eighteen patients were identified. Organisms isolated at diagnosis from blood or graft site were Staphylococcus aureus 6 (MRSA 1), beta haemolytic streptococci 2, enteric organisms 9.There was no isolate from 2. One case had graft explantation and brief antimicrobial therapy. Seventeen patients had the graft retained. Of these, 14 received intravenous antimicrobial therapy for 6 weeks and 14 lifelong oral therapy. None died during their initial admission or within 30 days. During a mean follow-up of 57 months, 10 (59%) relapsed (median time 31 months, range 0--98), 4 (24%) underwent graft explantation and 10 (59%) died (median 40 months, range 1e 198). Four of 10 who relapsed had organisms isolated (all enteric). Patients treated with lifelong antimicrobial therapy and graft retention survived a median of 41 months, with low early mortality although over half relapsed. Empiric therapy should cover skin organisms and enteric organisms, even for those outside the post-operative period.

Interactive cardiovascular and thoracic surgery, 2010

We present a case of a male patient diagnosed with a large inferior pancreaticoduodenal artery (I... more We present a case of a male patient diagnosed with a large inferior pancreaticoduodenal artery (IPDA) aneurysm, associated with a fresh thrombotic occlusion of the celiac trunk. Given the risk of splanchnic ischaemia, radiologic embolisation of the aneurysm combined with celiac axis stenting was deemed unsafe. Management was therefore modified to elective revascularisation of the celiac axis prior to surgical resection of the aneurysm. A retropancreatic aorto-gastroduodenal artery bypass graft was performed prior to exposing and resecting the pancreaticoduodenal artery aneurysm. This ensured near uninterrupted retrograde supply to the celiac axis during the procedure. This is an effective, efficient and expeditious patient pathway for these rare and complex aneurysms complicated by celiac trunk involvement.

Journal of Surgical Research, 2007

improve endothelial function by elevating nitric oxide synthase activity and inhibiting adhesion ... more improve endothelial function by elevating nitric oxide synthase activity and inhibiting adhesion molecule expression and may, therefore, inhibit IRI-induced neutrophil extravasation. Although statins are protective against myocardial IRI and stroke, a role for statins in ameliorating skeletal muscle IRI has not yet been confirmed. This study, therefore, addressed the hypothesis that simvastatin would attenuate the severity of tissue damage during skeletal muscle IRI.

Journal of Surgical Research, 2004

Background. This study aimed to devise a simple, reproducible method of subtotal hepatectomy in a... more Background. This study aimed to devise a simple, reproducible method of subtotal hepatectomy in a large animal model. Such an experimental model could be useful in the investigation of liver regeneration and liver insufficiency after partial hepatectomy. Equally, this technique could be used for assessing the effect of artificial liver support systems on both liver function and regeneration.

Journal of Investigative Surgery, 2008

Ischemia-reperfusion injury (IRI) to the lower extremities causes both local damage and serious d... more Ischemia-reperfusion injury (IRI) to the lower extremities causes both local damage and serious dysfunction to remote organs, including lungs and kidneys. However, effective therapies are not available. This study aims to determine if simvastatin reduced the severity of remote damage following IRI. Rats were given simvastatin before hind limb IRI. Lung and kidney tissues were assessed for neutrophil infiltration using myeloperoxidase assays and basement membrane damage by quantitative immunohistochemical measurement of collagen IV. The effect of nitric oxide synthase (NOS) inhibition on remote damage after IRI and simvastatin was assessed using the NOS inhibitor, L-NIO. Simvastatin (2 mg/kg) protected kidneys against IRI-induced neutrophil infiltration. Simvastatin also inhibited the IRI-induced activation of MMP-9 in the lungs. However, paradoxically, simvastatin exacerbated IRI-induced neutrophil infiltration into the lungs. IRI induced collagen IV degradation in the lungs but not in the kidneys. The degree of collagen breakdown in the lungs was significantly ameliorated by 2 mg/kg simvastatin. NOS inhibition markedly protected both the lungs and the kidneys against IRI-induced neutrophil infiltration but did not alter collagen IV degradation. Administration of simvastatin to L-Nio-treated animals enhanced the degree of protection against IRI-induced neutrophil infiltration in the kidneys but not in the lungs. Simvastatin protects against remote IRI-induced damage in the lungs and kidneys, suggesting statins may reduce the severity of IRI during major vascular surgery.

European Journal of Vascular and Endovascular Surgery, 2002

Objectives: to determine the role of matrix metalloproteinases, MMP-2 and MMP-9, in reperfusion i... more Objectives: to determine the role of matrix metalloproteinases, MMP-2 and MMP-9, in reperfusion injury following skeletal muscle ischaemia and whether inhibition of MMPs by doxycycline protects against tissue damage. Methods: rats were anaesthetised and a tourniquet applied to the proximal thigh to occlude blood flow. Four hours of ischaemia was followed by reperfusion for 0, 4, 24 or 72 h. Two further groups received doxycycline for 7 days prior to bilateral ischaemia and 24 h reperfusion. Skeletal muscle from both limbs, kidneys and lungs were harvested for zymography and immunohistochemical staining for type IV collagen.

European Journal of Vascular and Endovascular Surgery, 2004

European Journal of Vascular and Endovascular Surgery, 2003

Hyperhomocysteinaemia has recently been identified as an important risk factor for atheroscleroti... more Hyperhomocysteinaemia has recently been identified as an important risk factor for atherosclerotic vascular disease. Screening for hyperhomocysteinaemia has been recommended, however, the incidence of hyperhomocysteinaemia in vascular patients is not known. To determine the incidence of hyperhomocysteinaemia in vascular patients, to determine the relation of hyperhomocysteinaemia with folate, vitamin B12 levels and lipid profiles in vascular patients. To examine if there is a relationship between the degree of vascular injury and homocysteine concentration. New vascular patients at The Queen Elizabeth Hospital were recruited and divided into peripheral, and aneurysmal presentations. Patients demographics were recorded, blood samples were taken for fasting lipid profile, and homocysteine concentration. Samples were also taken for vitamin B12, plasma and red cell folate levels. Sixty age and sex matched controls were included for comparison. One hundred and twenty-six patients have been recruited, (95 men and 31 women) with a median age of 68 years (61-74 years). The incidence of elevated homocysteine, and cholesterol levels was 33, 47 and 24%. The levels of vitamin B12 and folate were normal in all patients. Homocysteine was elevated in 27% of claudicants, 50% of patients with rest pain and 53% of patients with an aortic aneurysm. There is a high rate of hyperhomocysteinaemia in vascular patients with a higher incidence in patients with rest pain. There was also a high incidence of elevated homocysteine levels in patients with an abdominal aortic aneurysm. The rate of growth of these aneurysms is currently under review. Low folate or B12 concentrations is not the cause of raised homocysteine levels.

British Journal of Surgery, 2003

Background: In-depth knowledge of pig liver anatomy allows potential research into segmental live... more Background: In-depth knowledge of pig liver anatomy allows potential research into segmental liver resections and hepatic regeneration, as well as liver transplantation techniques. The segmental anatomy, however, remains largely unknown. This study aimed to delineate the segmental anatomy of the porcine liver in comparison with that of the human.

ANZ Journal of Surgery, 2009

Background: Individual experience in the investigative, planning and operative aspects of lower l... more Background: Individual experience in the investigative, planning and operative aspects of lower limb musculoskeletal tumours is often small, making comparison between results difficult. The aim of the study was to describe the recent experience of a single tertiary referral unit performing limb salvage surgery, to identify areas of concern that are amenable to intervention and to provide clinicians an understanding of the surgical options. Methods: Nine patients with peripheral limb musculoskeletal tumours are described. Four patients had a leiomyosarcoma, and one each of osteosarcoma, synovial chondrosarcoma, synovial sarcoma, liposarcoma and recurrent malignant peripheral nerve sheath tumour. Results: Thirty-day mortality was nil. Two patients (one with a leiomyosarcoma and one with an osteosarcoma) died at 6 months follow-up because of pulmonary metastases. One patient with synovial chondrosarcoma developed a local recurrence and underwent an above-knee amputation. Six patients at 18 months follow-up are alive with no evidence of local recurrence and a functional lower limb. Conclusion: These cases are a challenge to the clinicians, radiologists and pathologists. Review by a multidisciplinary team can produce successful results with low post-operative morbidity and mortality. Longer follow-up is required to determine the long-term implications.

AIMS: Rapid access carotid endarterectomy (RACE) is the gold standard for stroke prevention in sy... more AIMS: Rapid access carotid endarterectomy (RACE) is the gold standard for stroke prevention in symptomatic patients with 50–99% internal carotid artery stenosis. Diagnosis and referral of eligible patients may be delayed by disruption to local health services. The aim of this study was to evaluate whether service provision was maintained at an appropriate standard (<2 weeks) following a natural disaster.