Papers by George Hamilton
International Journal of Angiology, 2008
OBJECTIVE: To systematically review the randomized controlled trials that have evaluated the effi... more OBJECTIVE: To systematically review the randomized controlled trials that have evaluated the efficacy of knee-length (KL) compression stockings for thromboprophylaxis in air travellers. METHOD: After an electronic database search, the randomized controlled trials that studied passengers on long-haul flights were selected and analyzed to generate summative data. RESULTS: Nine trials studying participants using KL stockings were analyzed. Forty-six of 1261 participants randomly assigned to the control group developed deep vein thrombosis (DVT), compared with two of 1237 participants (0.16%) in the KL stockings group. The weighted risk difference was-0.034, which indicated that the absolute difference was 3.4% in the incidence of DVT, in favour of KL stockings. The number needed to treat with KL stockings to avoid one case of DVT was 29.4. However, there was significant heterogeneity among trials. The RR for DVT was 0.08 in high-risk participants and 0.14 in low-to medium-risk participants. CONCLUSION: KL stockings are effective for thromboprophylaxis in air travellers at low, medium and high risk of DVT. The use of KL stockings should form an important part of air traveller education on lowering the burden of DVT. The results of the present meta-analysis can be used to advise travellers on their risk of DVT and preventive strategies.
Influenza-like illness in acute myocardial infarction patients during the winter wave of the infl... more Influenza-like illness in acute myocardial infarction patients during the winter wave of the influenza A H1N1 pandemic in London: a case-control study. BMJ Open 2013;3:e002604.
Postgraduate Medical Journal, 1993
Summary During a 6 year period 60 patients with atherosclerotic renovascular disease were followe... more Summary During a 6 year period 60 patients with atherosclerotic renovascular disease were followed by a single renal unit. Angiotensin converting enzyme inhibitors were being taken by 22% of patients at the time of diagnosis of the atherosclerotic renovascular disease. Intervention to revascularize renal tissue by surgery or angioplasty was performed in 32 patients. Revascularization was not undertaken because of unilateral disease, patient preference, poor operative risk or renal size. The mean age for the nonintervention group was 66.9 years and 63.4 years for the intervention group. Peripheral vascular, disease was common in both groups (96% nonintervention group versus 86% intervention group). There was a statistically significant difference in improvement in renal function in the intervention group (34.4% versus 10.7%) in spite of more patients being dialysis dependent in the intervention group (28.1% versus 14.3%). There was no statistically significant difference in survival ...
Journal of Vascular Surgery, 2002
We have also recently encountered abdominal compartment syndrome (ACS) after an elective procedur... more We have also recently encountered abdominal compartment syndrome (ACS) after an elective procedure. The patient, a 69-year-old man, underwent bilateral renal artery revascularization for worsening chronic renal failure. This was done through a rooftop incision. On the left side, a splenorenal end-to-end anastomosis was performed. On the right side, there was a failed attempt to revascularize using the hepatic artery, and thus an 8-mm Gortex graft was used as a jump graft from the infrarenal aorta. Perioperatively the patient had a myocardial infarction. Twenty-four hours after the procedure, the patient became unstable and required increased ventilatory support. Oliguria developed, and the patient's abdomen was tense and distended. A clinical diagnosis of ACS was made and confirmed when there was an immediate improvement in the ventilatory requirements following abdominal decompression. The laparotomy findings were 1500 mL of bloodstained fluid and a hematoma around the liver. The fluid was drained, and no active source of bleeding was encountered. However, 3 to 4 hours after the decompression, further complications again developed from the patient's ischemic heart disease, including a labile blood pressure and arrhythmias. This required cardiac pacing and led to further deterioration of his renal function, which required hemofiltration. Following a prolonged stay in the intensive care unit the patient recovered and is awaiting discharge. Our case, along with that of Sullivan at al, has shown that even 1200 to 1500 mL of intraabdominal fluid can lead to ACS. In our case the diagnosis was made clinically because of the classical clinical signs of increasing ventilatory support and oliguria that was subsequently confirmed with the immediate improvement in the patient's condition. 1,2 The subsequent delayed recovery was attributed to ongoing cardiac arrhythmias and not thought to be mainly caused by the ACS.
Journal of Vascular Surgery, 2010
Objectives: TWO2 proposes an option in the management of RVU. Primary endpoint is ulcer healing a... more Objectives: TWO2 proposes an option in the management of RVU. Primary endpoint is ulcer healing at 12 weeks and secondary endpoint is Q-TWiST. Methods: 46 ulcers were managed using TWO2 therapy and 37 ulcers with CCD. Demographics and risk factors were similar in both groups. All ulcers were CEAP C6, s. Results: The mean reduction in ulcer surface area at 12 weeks was 96% in the TWO2 therapy group, compared to 61% in the CCD group. At 12 weeks, 80% of TWO2 managed ulcers were completely healed, compared to 35% of CCD ulcers (p Ͻ 0.0001). Median time to full healing was 45days in TWO2 patients and 182days in CCD patients (p Ͻ 0.0001). 32/46 of TWO2 ulcers showed reverse gradient of healing. 9/19 MRSA positive ulcers managed with TWO2 were rendered MRSA negative after 5 weeks, compared to none of the 17 MRSA positive CCD ulcers. The pain score threshold in TWO2 managed patients improved from 8 to 3 by 13 days. Q-TWiST was significantly longer at 24.25 months for TWO2 and 10.5 months for CCD with p Ͻ 0.0001. After 36 months follow-up, 8 of the 13 healed CCD ulcers showed recurrence compared to none of the 37 TWO2 healed ulcers. No local or systemic complications were encountered in either treatment group. Conclusions: TWO2 is prudent, effective and valuable in managing RVU up to 36 months and slashes time needed for RVU healing. TWO2 is successful in pain alleviation, MRSA elimination. TWO2 radically degrades recurrence rates and thus enhances the quality of life and has superior Q-TWiST over CCD.
Journal of Vascular Surgery, 2010
antegrade subintimal angioplasty. The site of initial technical failure was the popliteal artery ... more antegrade subintimal angioplasty. The site of initial technical failure was the popliteal artery in 12 patients and the proximal trifurcation vessels in two. Technical success was achieved in all 14 patients. There were no complications from the distal arterial access in any of the patients, documented in all cases by noninvasive lab assessment. Conclusions: In a selected population of patients with femoropopliteal arterial occlusion, distal arterial access in the dorsalis pedis or posterior tibial artery may allow technical success to be achieved. Using the distal artery for retrograde access may be an important adjunct for treatment of complicated femoropopliteal occlusions.
Journal of Vascular Surgery, 2013
Journal of Vascular Surgery, 2013
Journal of Vascular Surgery, 2004
Journal of Vascular Surgery, 2012
(67%) had a minor infarct (Ͻ25% of cortex), 9 (16%) moderate (25-50% of cortex), and 2 (4%) sever... more (67%) had a minor infarct (Ͻ25% of cortex), 9 (16%) moderate (25-50% of cortex), and 2 (4%) severe (Ͼ50% of cortex). All but one patient were treated nonoperatively, using anticoagulation in 36 patients (86%) for a mean duration of 5.7 months (range 1-24), lifelong aspirin therapy in 29 (69%), and blood pressure control in 35 (83%). An attempt at ex-vivo repair in the operative patient failed. Thirty-four patients (81%) developed new onset of HTN within 1 year and were on 1.1 (range, 0-3) antihypertensive medications at 1 year. Three patients (7%) had a recurrent dissection, 41 (98%) had a normal creatinine, and no patient died or required dialysis over a mean follow-up of 35 months (range 0-279). Conclusions: Nonoperative management of ISDRA is feasible and safe in most patients.
European Journal of Vascular and Endovascular Surgery, 2014
At the Cleveland Clinic he was Vascular Surgeon in the Heart & Vascular Institute and also held j... more At the Cleveland Clinic he was Vascular Surgeon in the Heart & Vascular Institute and also held joint appointments in the Imaging Institute, the Lerner Research Institute of Biomedical Engineering and was Director of Endovascular Research. He brought great distinction to himself and the Clinic in the field of endovascular surgery for complex aortic disease, winning international recognition for translation of his many innovations to clinical application. Roy graduated from Cornell and then the University of Cincinnati Medical School. His residency was in general and vascular surgery at the University of Rochester Medical Centre where with typical foresight he recognised the potential for endovascular surgery. At a time when interventional training was not readily available to vascular surgical trainees, by special arrangement he undertook a Fellowship in Interventional Radiology at Rochester in 1996e7 followed by an Endovascular Fellowship at Malmo in 1997 with Professor Krassi Ivancev and Dr Bengt Lindblad. He recognised that understanding of both radiological and surgical care is the key and the foundation for modern vascular care. This training proved critical for Roy's future formulating in his mind new perspectives on treatment of complex aortic disease to the benefit of this high risk group of vascular patients. Once at the Cleveland Clinic he developed and directed a superb research and development programme based on a multidisciplinary team of engineers, mathematicians,
EJVES Extra, 2005
Haemangiopericytomas is a rare vascular tumour. The trunk and lower extremities are involved in m... more Haemangiopericytomas is a rare vascular tumour. The trunk and lower extremities are involved in most cases. Fifteen to twenty percent of haemangiopericytomas arise in the head and neck. We describe a case of a benign metachronous haemangiopericytoma in a 33-year-old man. The lesions were dealt by prompt surgical excision. This case highlights the need of close long-term follow-up of such patients with haemangiopericytoma even when benign. .
Role of PI3k/Akt pathway in cytoprotective effect of erythropoietin and erythropoietin derivatives in ischaemic human myotubes
Cardiovascular Pathology, 2013
British Journal of Surgery, 2000
Background The mechanism of action of stockings in symptom relief and treatment of venous insuffi... more Background The mechanism of action of stockings in symptom relief and treatment of venous insufficiency is still inadequately understood. Near-infrared spectroscopy (NIRS) provides continuous non-invasive monitoring of changes in tissue oxygen reserves and availability, by monitoring oxyhaemoglobin (HbO2), deoxyhaemoglobin (HbD) and cytochrome oxidase (CtO2). This study investigated the effect of stockings on calf muscle oxygenation during exercise using NIRS in patients with venous insufficiency. Methods Ten patients (mean(s.e.m.) age 56(5) years, seven women) with venous insufficiency participated in the study. Patients rested in a supine posture for 20 min. NIRS probes were attached to the calf at interoptodes spacing of 4 cm and initialized to zero. Calf oxygenation was continuously monitored during standing followed by a 5-min slow walk at 1·6 km h−1 with and without stockings chosen at random. A 30-min rest in the supine position was allowed between stockings. Pulse rate and p...
The Annals of The Royal College of Surgeons of England, 2007
Journal of Vascular Surgery, 1989
The Editors invite readers to submit letters commenting on the contents of articles that appear i... more The Editors invite readers to submit letters commenting on the contents of articles that appear in the Journal. Also welcome are brief communications in letter form reporting investigative or clinical observations without extensive documentation and with brief bibliography (five titles or less), not requiring peer review but open to critique by readers. Letters to the Editors should be no more than 500 words in length and they may have to be edited for publication.
Operative und interventionelle Gefäßmedizin, 2019
Gefäßerkrankungen können Frühgeborene, Säuglinge, Neugeborene, Kinder und Jugendliche betreffen. ... more Gefäßerkrankungen können Frühgeborene, Säuglinge, Neugeborene, Kinder und Jugendliche betreffen. Mit der sehr seltenen Ausnahme der juvenilen Arteriosklerose, u. a. bei familiärer Hyperlipidämie und Progerie, sind die Ursachen von Gefäßerkrankungen im Kindesalter kongenital oder entwicklungsbedingt, direkt oder iatrogen traumatisch, entzündlich und infektiös oder aber mit vaskulären Malformationen oder Tumoren assoziiert. Diese Erkrankungen sind auch bei Kindern vergleichsweise selten. Sie stellen immer eine Herausforderung dar, da der Umgang mit den schmalen Gefäßkalibern besondere Sorgfalt und Expertise für den Gefäßspezialisten erfordert. Gefäßerkrankungen bei Kindern und deren Therapie werden in diesem Kapitel beschrieben. 2 Spezielle Aspekte bei Kindern 2.1 Anatomische Besonderheiten der Arterien und Venen Die größte Herausforderung für die Behandlung von Gefäßerkrankungen der Kinder ist der schmale Durchmesser der Gefäße, insbesondere bei Frühgeborenen und Säuglingen. Der durchschnittliche Durchmesser der Arterien von Frühgeborenen bis hin zu Jugendlichen, die am häufigsten einer operativen Behandlung bedürfen, kann bei der Femoralarterie <1-7,5 mm bei 18 Jahren betragen (Tab. 1). Gefäßspezialisten verfügen heute über ein sehr ausgefeiltes Armamentarium, um Katheter-basierte Eingriffe bis hin zu offen chirurgischen Eingriffen durchzuführen. Dennoch besteht ein Mangel an Materialien für schmale Durchmesser, die bei Neugeborenen oder kleinen Kindern angewandt werden können. Generell stellen Arterien mit einem Durchmesser von <2 mm die größten Herausforderungen sowohl für Katheter-basierte als auch für offene chirurgische Eingriffe dar. Wenn solche Eingriffe in Betracht gezogen werden müssen, ist die Kenntnis des vermutlichen Durchmessers der zu behandelnden Arterie und des äußeren Durchmessers der Vorrichtungen wichtig. Die Maßeinheit orientiert sich an der französischen Charriere-Skala (Abb. 1). 2.2 Anastomotische Faktoren Anastomosen bei Gefäßdurchmessern von <2 mm sind Herausforderung für nicht-spezialisierte Gefäßchirurgen, ausgenommen diejenigen, die sich einem mikrovaskulären Operationstraining unterzogen haben. Bei Gefäßanastomosensowohl arteriell zu arteriell als auch venös zu arteriellwird das Gefäß mit dem Kind wachsen. Daher ist eine Einzelnahttechnik erforderlich, die typischerweise mit feinem Nahtmaterial (7/0 und höher) durchgeführt wird. Im Allgemeinen sind die Nähte nicht absorbierbar; sie bestehen meist aus Polypropylen (Prolene). Eine Alternative besteht jedoch in der Anwendung von Polydioxanon oder absorbierbarem PDS zur Anwendung in solchen autologen Anastomosen in fortlaufender oder Einzelknopfnahttechnik. Angeschrägte End-zu-End-Anastomosen bieten eine optimale Möglichkeit, um nachfolgende Stenosen durch intimale Hyperplasie zu minimieren und so den Blutfluss zu optimieren. Für diese schmalen Gefäßanastomosen ist eine Lupenvergrößerung oder die Zuhilfenahme eines Operationsmikroskops notwendig, um die Ergebnisse zu verbessern. Der Herausgeber Eike Sebastian Debus hat diesen Beitrag übersetzt und freigegeben.
Visceral Vessels and Aortic Repair, 2019
Reperfusion injury is a process well recognised and understood by vascular surgeons where return ... more Reperfusion injury is a process well recognised and understood by vascular surgeons where return of arterialised blood flow to a previously ischaemic organ or tissue often results in a complex pathophysiological cascade ending in potentially irreversible cellular damage. The sequelae of this process are frequently seen in vascular surgery after reperfusion of a previously ischaemic lower limb. The resulting profoundly acute inflammatory syndrome gives rise to raised compartmental pressure within the muscles of the lower limb requiring fasciotomy. Reperfusion injury however can develop in several other surgical scenarios including coronary artery bypass grafting and other cardiac interventions, organ transplantation and major vascular surgery, in particular aortic aneurysm repair and carotid endarterectomy. Obviously in these scenarios, fasciotomy is not an option, and since the 1980s, there has been research into avoiding or at least mitigating reperfusion injury.
Vascular Medicine, 2020
Vascular malformations occur during early vascular development resulting in abnormally formed ves... more Vascular malformations occur during early vascular development resulting in abnormally formed vessels that can manifest as arterial, venous, capillary or lymphatic lesions, or in combination, and include local tissue overdevelopment. Vascular malformations are largely caused by sporadic somatic gene mutations. This article aims to review and discuss current molecular signaling pathways and therapeutic targets for vascular malformations and to classify vascular malformations according to the molecular pathways involved. A literature review was performed using Embase and Medline. Different MeSH terms were combined for the search strategy, with the aim of encompassing all studies describing the classification, pathogenesis, and treatment of vascular malformations. Major pathways involved in the pathogenesis of vascular malformations are vascular endothelial growth factor (VEGF), Ras/Raf/MEK/ERK, angiopoietin-TIE2, transforming growth factor beta (TGF-β), and PI3K/AKT/mTOR. These pathwa...
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Papers by George Hamilton