Gregor D. Shanik

Mater Misericordiae University Hospital, Dublin, Leinster, Ireland

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Publications (82)120.04 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Endovascular technology has revolutionised the management of abdominal aortic aneurysmal disease but the less frequent occurrence of pathology in the thoracic aorta has meant that evidence demonstrating the primacy of endovascular treatment strategies in this portion of the vessel is less convincing. Herein we summarise the best available evidence to date. A comprehensive search of the surgical and radiological literature using the search term 'endovascular thoracic aorta' was conducted. The vast majority of patients treated by thoracic aortic stent grafting have had their treatment outside the context of a randomised trial. While it would seem that endovascular repair is the treatment of choice for the thoracic aorta, the present evidence is based on single centre case series and is anecdotal at best.
    The surgeon: journal of the Royal Colleges of Surgeons of Edinburgh and Ireland 03/2009; 7(1):24-30. DOI:10.1016/S1479-666X(09)80063-2 · 2.18 Impact Factor
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    ABSTRACT: While endovascular aortic aneurysm repair (EVAR) has significantly reduced the morbidity associated with open surgery, efforts continue to minimise the surgical insult to the patient. We report our experience of percutaneous EVAR. Since June 2005, 17/20 EVARs (85%) have been attempted percutaneously by deployment of two Perclose) devices into each femoral artery prior to passage of the device sheath. The sutures are left untied until the sheath is removed at the end of the procedure, when haemostasis is obtained. Patients were entered onto a prospectively maintained database and followed up at regular intervals in a dedicated EVAR clinic. Access and subsequent graft deployment was successful in all the 17 cases. The range of defects closed ranged from 12-24 Fr. Five patients (29%) required open groin exploration at the end of the procedure to achieve haemostasis. There was a significantly lower incidence of wound complications in the percutaneous EVAR group (6 vs. 10% open cutdown cases, P < 0.05, Mann-Whitney U test). Percutaneous EVAR is both a feasible and safe method of performing endovascular abdominal aortic aneurysm repair, which is associated with a reduction in wound complication rates.
    Irish Journal of Medical Science 03/2008; 177(1):49-52. DOI:10.1007/s11845-008-0122-6 · 0.83 Impact Factor
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    ABSTRACT: All patients who presented to St James’s Hospital with rest pain, tissue loss, or both between January 1998 and January 2002 and who had an infrainguinal operative intervention were identified. Patients who were treated nonoperatively or who underwent a prior or concomitant aortoiliac bypass or endovascular procedure were excluded. Angioplasty or bypass was performed as the initial vascular procedure on 333 patients. Patients were analyzed on an intention-to-treat basis. There were 180 patients (198 limbs) in the angioplasty group. During the same period, 153 patients (162 limbs) underwent a primary infrainguinal bypass procedure. Angioplasty was the preferred procedure in all patients for whom a stump or portion of superficial femoral artery was patent. Bypass was the preferred procedure in patients with either a flush occlusion of their superficial femoral artery or an inadequate distal target vessel for angioplasty. Other factors that favored bypass were renal impairment and allergy to contrast media.
    Journal of Vascular Surgery 03/2006; 43(3):504-512. DOI:10.1016/j.jvs.2005.11.016 · 3.02 Impact Factor
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    Martin V Forlee · Maria Grouden · Dermot J Moore · Gregor Shanik ·
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    ABSTRACT: This report describes an ischemic stroke after foam injection sclerotherapy of varicose veins in a patient with a patent foramen ovale. Foam injection sclerotherapy has created resurgence in the minimally invasive treatment of varicose veins. The United States Food and Drug Administration halted a clinical phase 2 trial of a commercial preparation of polidocanol microfoam in 2003 because of concerns relating to possible gas embolism. These trials were recommenced in July 2005. Neurologic complications such as transient visual disturbances and transient confusional states have previously been reported. This case, with its strong circumstantial evidence, illustrates the previously unconfirmed potential for embolic complications using this technique.
    Journal of Vascular Surgery 02/2006; 43(1):162-4. DOI:10.1016/j.jvs.2005.09.032 · 3.02 Impact Factor

  • Irish Journal of Medical Science 03/2005; 174:35-35. DOI:10.1007/BF03170155 · 0.83 Impact Factor
  • Mark D Morasch · Gregor D Shanik ·
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    ABSTRACT: Peripheral embolization of macroscopic tumor fragments is an uncommon occurrence. A patient with a previously undiagnosed primary lung adenocarcinoma who presented with an acutely ischemic limb is described. Following review of the literature, the characteristics of tumor embolization are discussed.
    Annals of Vascular Surgery 04/2003; 17(2):210-3. DOI:10.1007/s10016-001-0251-0 · 1.17 Impact Factor

  • Irish Journal of Medical Science 01/2003; 172(1):s1:41. · 0.83 Impact Factor
  • D. Evoy · S. Sultan · M. P. Colgan · D. Moore · G. Shanik ·
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    ABSTRACT: Both angioplasty and infrainguinal bypass procedures may be used to achieve limb salvage in patients with critical ischaemia. The authors investigated the effect of the introduction of angioplasty on the frequency with which infrainguinal bypass was performed and, second, the changes in outcome of infrainguinal bypass following the introduction of angioplasty. All patients had critical ischaemia of the leg. Three patient groups were studied: 215 patients undergoing infrainguinal bypass before the introduction of angioplasty (1986–1991), 216 patients who had infrainguinal bypass after the introduction of angioplasty (1993–1998) and 193 patients undergoing angioplasty in the same 5-year interval (1993–1998). The age and risk profile of the three groups was identical. The overall caseload increased by 19 per cent following the introduction of angioplasty. Primary and secondary patency rates were superior for bypass compared with angioplasty, but were similar for the two bypass groups (5-year primary patency rate 60 per cent versus 18-month primary patency rate 45 per cent; 5-year secondary patency rate 80 per cent versus 18-month secondary patency rate 60 per cent). By 18 months 26 per cent of patients having angioplasty had gone on to have bypass. The limb salvage rate of 90 per cent at 1 year was similar for all groups. Survival was significantly higher in the group of patients undergoing bypass from 1993 to 1998 compared with the other two groups (80 versus 60 per cent; P < 0·0002). The introduction of angioplasty has increased overall workload. Angioplasty has a lower patency rate than bypass but a comparable limb salvage rate, making it a suitable alternative to bypass in the management of patients with critical ischaemia. © 2001 British Journal of Surgery Society Ltd
    British Journal of Surgery 12/2002; 88(4):620 - 620. DOI:10.1046/j.1365-2168.2001.01757-57.x · 5.54 Impact Factor
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    ABSTRACT: The widespread use of intraarterial thrombolytic therapy has been based on perceived benefits over operative treatment and the downgrading of the magnitude of subsequent surgery. Thirty-three patients who had thrombolysis for peripheral artery occlusion were retrospectively analyzed at St. James's Hospital from 1991 to 1997. One patient received streptokinase unsuccessfully. Five other patient's records were inadequate for analysis. Twenty-seven patient's notes were analyzed for risk, duration of occlusion, duration of treatment, dosage of tissue plasminogen activator (tPA) and conduits thrombolysed. There were 15 males and 12 females. The mean age was 62 years (range, 20-87). Fourteen were current or reformed smokers. Five were diabetic. Indications for treatment included acute graft occlusion (n=13), embolus (n=6), and primary and secondary arterial thrombosis (n=8). Duration of occlusion was less than 24 hours in seven, 1 to 7 days in ten, and more than 7 days in ten patients. Twelve (44.44%) patients had complete clot lysis, four (14.81%) had partial clearance, and 11 (40.74%) remained occluded. Eight (29.63%) had serious complications including one death. Eighteen (66.66%) patients needed further surgical intervention to maintain graft patency. Data were analyzed using the chi-square and pooled t test. No significant difference was observed in results from thrombolysis from different conduits, gender, etiology, or smoking history. Increased duration of tPA administration was associated with an increased risk of failure. Administration of total dosages greater than 60 mg was associated with a higher risk of failure. Diabetics had a poor outcome (p=0.0520). Only 44 % of patients successfully underwent lysis. A primary surgical option may be a more sensible course than lysis, given that the vast majority of patients ended up having surgery anyway.
    Vascular and Endovascular Surgery 09/2002; 36(5):351-6. DOI:10.1177/153857440203600504 · 0.66 Impact Factor
  • Sultan S · Fulton G · Colgan MP · Madhavan P · Moore D · Shanik G ·

    European Journal of Vascular and Endovascular Surgery 09/2002; · 2.49 Impact Factor
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    ABSTRACT: The most prevalent lesion of the vertebral artery is an atheromatous plaque located at its origin from the subclavian artery. A case of successful management of a symptomatic vertebral artery aneurysm due to Ehlers-Danlos syndrome is reported. The patient had asymptomatic posterior intracerebral artery dissection on the contralateral side. A common carotid artery to V-3 segment bypass using reversed saphenous vein graft was carried out. Avulsion of the V-2 segment occurred peroperatively and endovascular coil embolization of the vertebral artery aneurysm was performed. Endovascular equipment and training must be in the armamentarium of vascular surgeons as more complex cases are being treated, which demands new approaches for ultimate clinical success. This unique case outlines what might unexpectedly occur. Endovascular intervention as an adjuvant procedure provides a satisfactory outcome in what could have been a catastrophe.
    Vascular and Endovascular Surgery 09/2002; 36(5):389-92. DOI:10.1177/153857440203600510 · 0.66 Impact Factor
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    ABSTRACT: To report the successful endovascular embolization of a pancreaticoduodenal aneurysm (PDA). A 56-year-old man with a history of pancreatitis presented with insidious, progressive epigastric pain for the preceding 6 months. Contrast-enhanced computed tomography (CT) and selective hepatic digital subtraction angiography identified a 7.7-cm aneurysm that arose from the pancreaticoduodenal branch of the gastroduodenal artery. Through a percutaneous common femoral approach, 10 stainless steel coils were delivered to occlude the aneurysm. A single coil detached and became lodged in a small branch of the right hepatic artery without sequelae. At 26 months, duplex and CT scans show continued occlusion of the aneurysm. Transcatheter coil embolization should be the first choice treatment for aneurysms of the pancreaticoduodenal artery.
    Journal of Endovascular Therapy 05/2002; 9(2):225-8. DOI:10.1583/1545-1550(2002)009<0225:EMOAPA>2.0.CO;2 · 3.35 Impact Factor
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    S Sultan · S Nicholls · P Madhavan · M P Colgan · D Moore · G Shanik ·
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    ABSTRACT: We report our initial results of a prospective study of duplex ultrasound-guided injection (UGTI ) of thrombin in the management of femoral artery pseudo-aneurysms. We used human thrombin to avoid the increase in the human antibodies directed against fibrinogen, with the use of bovine thrombus, that preclude further utilisation of the bovine fibrin glue during cardio-thoracic surgery. From 1999 to 2001, 19 patients, aged 69 (range 52-85) years presented with 21 femoral pseudo-aneurysms were treated. The mean pseudoaneurysm diameter was 30 (15-55) mm. All but two were secondary to cardiac procedures and the common femoral artery was the injured vessel in all instances. Patients were referred within 2-21 days following their iatrogenic injury. Immediate thrombosis of the sac occurred in 19 (90%) of the 21 pseudo-aneurysms. After a second injection, complete occlusion occurred in the remaining two patients. Two patients (CI 95%; 1-19) with three femoral pseudo-aneurysms developed leg pain. Duplex ultrasound follow-up showed two recurrences (9.5% - CI 95%; 1-19) and both were treated by repeat UGTI. There was no conversion to surgical repair. This percutaneous minimally invasive technique is safe and effective in the management of iatrogenic pseudo-aneurysms in this high-risk group of patients. Human thrombin has significant advantages over bovine thrombin.
    European Journal of Vascular and Endovascular Surgery 01/2002; 22(6):542-5. DOI:10.1053/ejvs.2001.1519 · 2.49 Impact Factor

  • Advances in Vascular Surgery, Edited by JST Yao and WH Pearce, 12/2001: chapter 25: pages 265-276; Parmentier Publishing Services.
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    ABSTRACT: Vascular closure staples (VCS) provide a novel technique for fashioning vascular anastomoses, allowing a single operator to perform suture-less anastomoses. They may be used primarily or in an adjuvant role. When VCS are compared to a running suture, advantages include the avoidance of intimal damage, platelet aggregation and intimal hyperplasia at the anastomotic suture line, and a shorter time taken to complete the anastomosis. We report our early experience using VCS in an array of vascular anastomoses and conclude that VCS are a useful addition to the vascular surgeon's armamentarium. They help to decrease the time taken to construct an anastomosis, and are particularly useful in an adjuvant setting, complementing conventionally placed sutures.
    Annals of Vascular Surgery 06/2001; 15(3):338-42. DOI:10.1007/s100160010084 · 1.17 Impact Factor
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    S Sultan · D Evoy · S Nicholls · M P Colgan · D Moore · G Shanik ·
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    ABSTRACT: transfemoral endoluminal aortic management (TEAM) is technically feasible in the treatment of infrarenal abdominal aortic aneurysms but its advantage over conventional repair is unproved. We report our initial experience, learning curve and technical difficulties encountered during the process of establishing this novel technique in our institute. over a 3-year period 400 cases of abdominal aortic aneurysms were reviewed; only 58 cases (15%) were suitable for endovascular repair under our TEAM protocol and 36 (9%) were offered endovascular intervention. They were mainly high-risk patients (85% ASA III and IV) with a mean age of 72 years. Thirty-three bifurcated grafts, two straight tube grafts and one aorto mono-iliac graft were deployed. We oversized the graft by 15-20% to the diameter of the aortic neck and both common iliac arteries. two cases (6%-95% CI: 1-19%) had on-table conversion because of ruptured common iliac arteries. Peri-operatively there were two deaths from multi-organ failure. Transient renal failure occurred in two patients and three patients (9%) suffered a non-fatal myocardial infarction. Sixteen percent of patients had a groin wound problem. The mean hospital stay was 7 days. Five minor endoleaks (15%) were identified and sealed at 30 days. One secondary endoleak was identified at 18 months because of a patent juxta-renal lumbar artery. No secondary cuffs or extensions were used. Mean follow-up was 29 months and all grafts remained patent. The technical, clinical, continuous and secondary success rates were 78%, 91%, 89% and 91% respectively with TEAM. endovascular training, patient selection and learning curve impose an impact on the final outcome. Until a reliable hard point is reached so that endovascular repair could be exercised in routine practice, the use of TEAM must be questioned in high-risk patients, and should be performed under clinical trial conditions using strict selection criteria.
    European Journal of Vascular and Endovascular Surgery 02/2001; 21(1):70-4. DOI:10.1053/ejvs.2000.1282 · 2.49 Impact Factor
  • Velander P · Fulton G · Sultan S · Butcher W · Colgan MP · Madhavan P · Moore D · Shanik G ·

    Irish Journal of Medical Science 01/2001; 170(1):Supp 1: 25. · 0.83 Impact Factor
  • Sweeney KJ · Evoy D · Kell MR · Sultan S · Coates C · Moore DJ · Shanik GD · Reynolds JV ·

    Irish Journal of Medical Science 01/2001; 170(1):Supp 1: 19. · 0.83 Impact Factor
  • Sultan S · Fulton G · Butcher W · Colgan MP · Madhavan P · Moore D · Shanik G ·

    Irish Journal of Medical Science 01/2001; 170(1):Supp 1: 27. · 0.83 Impact Factor
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    ABSTRACT: To report a combined endovascular and open technique to manage a suprarenal mycotic aortic aneurysm using a stent-graft partially covered with a section of autologous artery. A 50-year-old was hospitalized for staphylococcal septicemia and severe back pain. A previously diagnosed 3-cm abdominal aortic aneurysm was found to have expanded 2 cm in 3 weeks. Aortography documented some periaortic thickening and 2 mycotic aneurysms, one posterior at the level of the superior mesenteric artery and the second at the aortic bifurcation. After intensive antibiotic therapy, an endovascular approach to exclude the suprarenal mycotic aneurysm was undertaken in tandem with surgical excision of the infrarenal aneurysm. The harvested right common iliac artery was used to partially cover a Palmaz stent, which was deployed under direct vision just above the renal artery ostia so that the covered portion of the stent excluded the aneurysm. A right axillofemoral bypass with a femorofemoral bypass completed the revascularization. Postoperatively, the patient developed renal failure, ischemic colitis necessitating a left hemicolectomy, and paraplegia. Although the patient is paralyzed, the aneurysm remains excluded with patent visceral vessels at 12 months following surgery. No organisms were grown from excised aortic tissue, and no signs of recurrent infection have been seen. Stent-graft repair may be able to lessen the invasiveness and reduce the morbidity associated with treatment of mycotic aortic aneurysms.
    Journal of Endovascular Therapy 11/2000; 7(5):404-9. DOI:10.1583/1545-1550(2000)007<0404:SMAEUA>2.0.CO;2 · 3.35 Impact Factor

Publication Stats

1k Citations
120.04 Total Impact Points


  • 2009
    • Mater Misericordiae University Hospital
      Dublin, Leinster, Ireland
  • 1982-2008
    • Saint James School Of Medicine
      Park Ridge, Illinois, United States
  • 1983-2006
    • St. James's Hospital
      • Department of Vascular and Endovascular Surgery
      Dublin, Leinster, Ireland
  • 1993
    • Trinity College Dublin
      • Department of Gastroenterology and Hepatology
      Dublin, L, Ireland