Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Michael P. Jenkins is active.

Publication


Featured researches published by Michael P. Jenkins.


European Journal of Vascular and Endovascular Surgery | 2009

Treatment of Complex Aneurysmal Disease with Fenestrated and Branched Stent Grafts

Colin Bicknell; Nicholas Cheshire; Celia V. Riga; P. Bourke; J.H.N. Wolfe; R.G.J. Gibbs; Michael P. Jenkins; M. Hamady

OBJECTIVES To describe our experience of treating juxtarenal (JRAAAs <4mm neck) and thoracoabdominal aortic aneurysms (TAAAs) using fenestrated and branched stent graft technology. DESIGN Prospective single centre experience. METHODS Since 2005, 29 fenestrated/branched procedures have been performed. 15 patients are studied with JRAAAs (n=7; median neck length 0mm (IQR 0-3.8)) or TAAAs (type I (n=2), III (n=2), IV (n=4)). ASA grade III in 12/15. Maximum diameter of aneurysm 64 mm (56-74 mm). Aneurysms were excluded using covered stents or branches from the main body to patent visceral vessels (40 target vessels total). Pre-operative and follow-up CT scans (1, 3, and 12 months) were analysed by a single Vascular Interventional Radiologist. RESULTS Technical success for cannulation and stenting of target vessels was 98%. In-hospital mortality was 0%. One patient underwent conversion to open repair. Five had major complications including one paraplegia (type III TAAA) with subsequent recovery. Median length of stay was 9 days (IQR 7-18.75). At a median follow-up of 12 months (9-14), CT confirmed 36/37 (97%) target vessels remain patent. Sac size increased >5 mm in one patient only. There were no type I endoleaks, three type II endoleaks (one embolised, two under surveillance) and three type III endoleaks (two successfully treated percutaneously, one aneurysm ruptured 18 months after endografting and died). CONCLUSION In selected patients, fenestrated and branched stents appear to be a safe and effective alternative to surgery for juxtarenal and thoracoabdominal aneurysms. The complication and mortality rates are low. The long-term durability of this procedure, however, needs to be proven.


Circulation | 2012

Early Results of Fenestrated Endovascular Repair of Juxtarenal Aortic Aneurysms in the United Kingdom

G. Ambler; Jonathan R. Boyle; C. Cousins; P.D. Hayes; T. Metha; T.C. See; K. Varty; A. Winterbottom; D.J. Adam; A.W. Bradbury; M.J. Clarke; R. Jackson; J.D. Rose; A. Sharif; V. Wealleans; R. Williams; L. Wilson; M.G. Wyatt; I. Ahmed; Rachel Bell; Tom Carrell; P. Gkoutzios; Tarun Sabharwal; R. Salter; M. Waltham; Colin Bicknell; P. Bourke; Nicholas Cheshire; Ian J. Franklin; A. James

Background— Fenestrated endovascular repair of abdominal aortic aneurysms has been proposed as an alternative to open surgery for juxtarenal and pararenal abdominal aortic aneurysms. At present, the evidence base for this procedure is predominantly limited to single-center or single-operator series. The aim of this study was to present nationwide early results of fenestrated endovascular repair in the United Kingdom. Methods and Results— All patients who underwent fenestrated endovascular repair between January 2007 and December 2010 at experienced institutions in the United Kingdom(>10 procedures) were retrospectively studied by use of the GLOBALSTAR database. Site-reported data relating to patient demographics, aneurysm morphology, procedural details, and outcome were recorded. Data from 318 patients were obtained from 14 centers. Primary procedural success was achieved in 99% (316/318); perioperative mortality was 4.1%, and intraoperative target vessel loss was observed in 5 of 889 target vessels (0.6%). The early reintervention (<30 days) rate was 7% (22/318). There were 11 deaths during follow-up; none were aneurysm-related. Survival by Kaplan–Meier analysis was 94% (SE 0.01), 91% (0.02), and 89% (0.02) at 1, 2, and 3 years, respectively. Freedom from target vessel loss was 93% (0.02), 91% (0.02), and 85% (0.06), and freedom from late secondary intervention (>30 days) was 90% (0.02), 86% (0.03), and 70% (0.08) at 1, 2, and 3 years. Conclusions— In this national sample, fenestrated endovascular repair has been performed with a high degree of technical and clinical success. Late survival and target vessel patency are satisfactory. These results support continued use and evaluation of this technique for juxtarenal aneurysms, but illustrate the need for a more robust evidence base.


Circulation | 2014

Endovascular Treatment of Mycotic Aortic Aneurysms A European Multicenter Study

Karl Sörelius; Kevin Mani; Martin Björck; Petr Sedivy; Carl-Magnus Wahlgren; Philip R. Taylor; Rachel E. Clough; Oliver Lyons; M.M. Thompson; Jack Brownrigg; Krassi Ivancev; Meryl Davis; Michael P. Jenkins; Usman Jaffer; Matthew J. Bown; Zoran Rancic; Dieter Mayer; Jan Brunkwall; Michael Gawenda; Tilo Kölbel; Elixène Jean-Baptiste; Frans L. Moll; Paul Berger; Christos D. Liapis; Konstantinos G. Moulakakis; Marcus Langenskiöld; Håkan Roos; Thomas Larzon; Artai Pirouzram; Anders Wanhainen

Background— Mycotic aortic aneurysm (MAA) is a rare and life-threatening disease. The aim of this European multicenter collaboration was to study the durability of endovascular aortic repair (EVAR) of MAA, by assessing late infection–related complications and long-term survival. Methods and Results— All EVAR treated MAAs, between 1999 and 2013 at 16 European centers, were retrospectively reviewed. One hundred twenty-three patients with 130 MAAs were identified. Mean age was 69 years (range 39–86), 87 (71%) were men, 58 (47%) had immunodeficiency, and 47 (38%) presented with rupture. Anatomic locations were ascending/arch (n=4), descending (n=34), paravisceral (n=15), infrarenal aorta (n=63), and multiple (n=7). Treatments were thoracic EVAR (n=43), fenestrated/branched EVAR (n=9), and infrarenal EVAR (n=71). Antibiotic was administered for mean 30 weeks. Mean follow-up was 35 months (range 1 week to 149 months). Six patients (5%) were converted to open repair during follow-up. Survival was 91% (95% confidence interval, 86% to 96%), 75% (67% to 83%), 55% (44% to 66%), and 41% (28% to 54%) after 1, 12, 60, and 120 months, respectively. Infection-related death occurred in 23 patients (19%), 9 after discontinuation of antibiotic treatment. A Cox regression analysis demonstrated non-Salmonella–positive culture as predictors for late infection–related death. Conclusions— Endovascular treatment of MAA is feasible and for most patients a durable treatment option. Late infections do occur, are often lethal, and warrant long-term antibiotic treatment and follow-up. Patients with non-Salmonella–positive blood cultures were more likely to die from late infection. # CLINICAL PERSPECTIVE {#article-title-32}Background— Mycotic aortic aneurysm (MAA) is a rare and life-threatening disease. The aim of this European multicenter collaboration was to study the durability of endovascular aortic repair (EVAR) of MAA, by assessing late infection–related complications and long-term survival. Methods and Results— All EVAR treated MAAs, between 1999 and 2013 at 16 European centers, were retrospectively reviewed. One hundred twenty-three patients with 130 MAAs were identified. Mean age was 69 years (range 39–86), 87 (71%) were men, 58 (47%) had immunodeficiency, and 47 (38%) presented with rupture. Anatomic locations were ascending/arch (n=4), descending (n=34), paravisceral (n=15), infrarenal aorta (n=63), and multiple (n=7). Treatments were thoracic EVAR (n=43), fenestrated/branched EVAR (n=9), and infrarenal EVAR (n=71). Antibiotic was administered for mean 30 weeks. Mean follow-up was 35 months (range 1 week to 149 months). Six patients (5%) were converted to open repair during follow-up. Survival was 91% (95% confidence interval, 86% to 96%), 75% (67% to 83%), 55% (44% to 66%), and 41% (28% to 54%) after 1, 12, 60, and 120 months, respectively. Infection-related death occurred in 23 patients (19%), 9 after discontinuation of antibiotic treatment. A Cox regression analysis demonstrated non-Salmonella–positive culture as predictors for late infection–related death. Conclusions— Endovascular treatment of MAA is feasible and for most patients a durable treatment option. Late infections do occur, are often lethal, and warrant long-term antibiotic treatment and follow-up. Patients with non-Salmonella–positive blood cultures were more likely to die from late infection.


European Journal of Vascular and Endovascular Surgery | 2011

Contemporary management of splanchnic and renal artery aneurysms: results of endovascular compared with open surgery from two European vascular centers.

F. Cochennec; Celia V. Riga; E. Allaire; Nick Cheshire; M. Hamady; Michael P. Jenkins; H. Kobeiter; J.N. Wolfe; J.P. Becquemin; R.G.J. Gibbs

INTRODUCTION Splanchnic and renal artery aneurysms (SRAAs) are uncommon but potentially life-threatening in case of rupture. Whether these aneurysms are best treated by open repair or endovascular intervention is unknown. The aim of this retrospective study is to report the results of open and endovascular repairs in two European institutions over a fifteen-year period. We have reviewed the available literature published over the 10 last years. METHODS All patients with SRAAs diagnosed from 1995 to 2010 in St Marys Hospital (London, UK) and Henri Mondor Hospital (Créteil, France) were reviewed. Preoperative clinical and anatomical data, operative management and outcomes were recorded from the charts and analyzed. RESULTS 40 patients with 51 SRAAs were identified. There were 21 males and 19 females with a mean age of 57 ± 14.9 years. The aneurysms locations were: 14 (27%) renal, 11 (22%) splenic, 7 (14%) celiac trunk, 7 (14%) superior mesenteric artery, 4 (8%) hepatic, 4 (8%) pancreaticoduodenal arcades, 3 (6%) left gastric and 1 (2%) gastroduodenal. 4 patients presented with a ruptured SRAA. 17 SRAAs in 16 patients were treated by open repair, 15 in 15 patients were treated endoluminally and 17 (mean diameter: 18 mm, range: 8-75 mm) were managed conservatively. One patient with metastatic pulmonary cancer with two mycotic aneurysms of the superior mesenteric artery (75 mm) and celiac trunk (15 mm) was palliated. After endovascular treatment, the immediate technical success rate was 100%. There was no significant difference between open repair and endovascular patients in terms of 30-day post-operative mortality rate and peri-operative complications. No in-hospital death occurred in patients treated electively. Postoperatively, four patients (1 ruptured and 3 elective) suffered non-lethal mild to severe complication in the open repair group, as compared with one in the endovascular group (p = .34). The mean length of stay was significantly higher after open repair as compared with endovascular repair (17 days, range: 8-56 days vs. 4 days, range: 2-6; p < .001). The mean follow-up time was 17.8 months (range: 0-143 months) after open repair, 15.8 months (range: 0-121 months) after endovascular treatment, and 24.8 (range: 3-64 months) for patient being managed conservatively. No late death related to the VAA occurred. In each group, 2 successful reoperations were deemed necessary. In the endovascular group, two patients presented a reperfusion of the aneurysmal sac at 6 and 24 months respectively. CONCLUSION No significant difference in term of 30-day mortality and post-operative complication rates could be identified between open repair and endovascular treatment in the present series. Endovascular treatment is a safe alternative to open repair but patients are exposed to the risk of aneurysmal reperfusion. This mandates careful long-term imaging follow up in patients treated endoluminally.


Journal of Endovascular Therapy | 2011

Pragmatic Minimum Reporting Standards for Endovascular Abdominal Aortic Aneurysm Repair

Jonathan R. Boyle; M.M. Thompson; S. Rao Vallabhaneni; Rachel Bell; John A. Brennan; Tom F. Browne; Nicholas Cheshire; Robert J. Hinchliffe; Michael P. Jenkins; Ian M. Loftus; Sumaira Macdonald; Mark J. McCarthy; Richard G. McWilliams; Robert Morgan; Olufemi A. Oshin; R. Mark Pemberton; Woolagasen R. Pillay; Robert D. Sayers; British Soc Endovasc Therapy

Jonathan R. Boyle, MD, FRCS1; Matt M. Thompson, MD, FRCS2; S. Rao Vallabhaneni, MD, FRCS, EBSQ-Vasc3; Rachael E. Bell, MS, FRCS4; John A. Brennan, MD, FRCS3; Tom F. Browne, FRCS5; Nicholas J. Cheshire, MD, FRCS6; Robert J. Hinchliffe, MD, FRCS2; Michael P. Jenkins, MS, FRCS, FEBVS6; Ian M. Loftus, MD, FRCS2; Sumaira Macdonald, FRCP, FRCR, PhD7; Mark J. McCarthy, PhD, FRCS8; Richard G. McWilliams, FRCR3; Robert A. Morgan, FRCR2; Olufemi A. Oshin, BEng, MRCS3; R. Mark Pemberton, MS, FRCS9; Woolagasen R. Pillay, FCS(SA), MMEDSc10; and Robert D. Sayers, MD, FRCS8 for the British Society of Endovascular Therapy


European Journal of Radiology | 2009

Update: Complications and management of infrarenal EVAR

J.V.P. Liaw; Martin Clark; R.G.J. Gibbs; Michael P. Jenkins; Nick Cheshire; M. Hamady

Endovascular aortic aneurysm repair (EVAR) is now an established technique for treating many patients with infrarenal abdominal aortic aneurysm. Familiarity with the complications associated with this technique and understanding treatment options are crucial for the lifelong performance of stent graft. This pictorial review article describes the currant role of different imaging modalities in surveillance and discusses the complications and its management strategies.


Journal of Vascular Surgery | 2011

The changing management of primary mycotic aortic aneurysms

Nadia Vallejo; Natasha Emma Picardo; Patricia Bourke; Colin Bicknell; Nick Cheshire; Michael P. Jenkins; J.H.N. Wolfe; R.G.J. Gibbs

OBJECTIVE The objective of this study is to examine contemporary management of primary mycotic aortic aneurysms in a single center. We have previously reported the management of mycotic aortic aneurysms in 15 patients between 1991 and 2001, and we hypothesized that management would change in the light of the evolution of endovascular aortic repair. METHODS A review of a prospectively collected database (2002-2009) of all patients presenting with mycotic aneurysms. RESULTS A total of 19 aneurysms were identified in 17 patients (12 men, 5 women) with a median age of 66.2 years (range, 49-82 years). All were symptomatic, and nine had contained rupture. There were five infrarenal, two juxtarenal, three Crawford type III, four type IV thoracoabdominal aortic aneurysms, and five descending thoracic aneurysms in the series. All thoracic aneurysms were excluded by thoracic endovascular aneurysm repair. Two patients underwent visceral hybrid endografting for type III thoracic aortic aneurysm; the third was treated with open repair. Four patients underwent open type IV repair. Two of the infrarenal aneurysms were treated with bifurcated endovascular aneurysm repair, and the other three and both juxtarenals with open repair with in situ reconstruction. There were three early (17.6%) and three late deaths (17.6%). The median follow-up was 30.5 months (range, 1-102 months). CONCLUSIONS The results of the latest series show that open surgery is still required in many cases. The introduction of endovascular techniques in the exclusion of mycotic aneurysms can be accomplished with acceptable results, and endovascular treatment has increased the therapeutic options for a difficult condition.


Thrombosis and Haemostasis | 2004

Lower limb venous haemodynamic impairment on dependency: quantification and implications for the "economy class" position.

Konstantinos T. Delis; Alison L. Knaggs; Tans N. Sonecha; Vasileios Zervas; Michael P. Jenkins; J.H.N. Wolfe

The role of stasis in venous disease is undisputed, yet surprisingly, its haemodynamic quantitation remains largely undefined. We investigated the phenomenon of venous stasis in the lower limb upon sitting and standing and project its implications to economy class aircraft passengers. 26 normal limbs, 13 subjects, age 29-54, selected after duplex, plethysmography and ABPI, had peak[V(peak)], mean[V(mean)] and minimum[V(min)] velocities, volume-flow[Q(venous)], pulsatility index [PI(venous)] and diameter obtained on horizontal, sitting (as in economy aircraft seats) and standing with duplex, at popliteal, femoral[FV] and common femoral[CFV]veins [differences in median %]. V(peak), V(mean) and Q(venous) decreased from horizontal to sitting in the CFV [57%, 71%, 31%, respectively], FV [51%, 70%, 34%] and popliteal [31%, 58%, 42%] (all, p<.001). V(peak),V(mean) and Q(venous) decreased further from sitting to standing in the CFV [26%, 44%, 25%, respectively], FV [21%, 42%, 27%] and popliteal [14%, 42%, 20%] (all, p <.001). Diameter, V(min) and PI(venous) increased from horizontal to sitting in the CFV [50%, 63%, 38%, respectively], FV [39%, 23%, 66%] and popliteal [21%, 14%, 84%] (all, p <.001)]. Diameter, V(min) and PI(venous) increased further from sitting to standing in CFV [10%, 22%, 19%, respectively; p =.004], FV [12%, 68%, 2%[ns]; p <.001)] and popliteal [14%, 50%, 24%; p =.017]. In all postures: V(peak), V(mean), Q(venous) and diameter at CFV exceeded FV (p <.025) and popliteal (p <.001) ones; also those at FV exceeded the popli-teal ones (p =.003), except for the diameter on horizontal. V(min) in popliteal was higher than in CFV (p =.003) or FV (p <.025), on horizontal and standing. PI(venous) in CFV was lower than in FV or popliteal (p <.025) on sitting. Right to left differences non-significant. [Wilcoxon(+Bonferroni) test: significance at p <.025] A shift from horizontal to sitting generates a most significant attenuation in Q(venous),V(peak) and V(mean) linked to a reciprocal increase in V(min), PI(venous) and vein diameter, with further exacerbation on standing. V(peak),V(mean) and Q(venous) decline with distance from groin enhancing venous stasis in the periphery. By restricting activation of the natural venous pumps, sitting cramped during long flights may protract the status of haemodynamic stagnation sustained on dependency which paired with marked venous dilatation generates a milieu that may promote thrombogenesis.


European Journal of Vascular and Endovascular Surgery | 2011

The suitability of thoraco-abdominal aortic aneurysms for branched or fenestrated stent grafts--and the development of a new scoring method to aid case assessment.

C.D. Rodd; S. Desigan; Nicholas Cheshire; Michael P. Jenkins; M. Hamady

OBJECTIVE To determine the proportion of TAAAs which might be suitable for pure endovascular repair based on aneurysm morphology and to develop an MDCTA based scoring system to grade case complexity. DESIGN 70 consecutive MDCTA of patients with TAAAs were analysed in relation to specific morphological characteristics. METHODS The characteristics included potential stent landing zone lengths, arch angulation, thoraco-abdominal aorta angulation, branch vessel origin stenosis, access tortuosity/diameter and aortic dissection. RESULTS 60% of TAAAs would be suitable for branched/fenestrated stent grafting but 40% are unsuitable due to adverse anatomy. 27% had an aortic arch angulation of ≤ 110° and 24% had descending thoracic aorta angulation of ≤ 90°. Significant ostial stenosis was identified in 31% of celiac arteries, 7% superior mesenteric arteries, 24% left renal artery and 19% right renal arteries. 11% of left common iliac and 7% right common iliac arteries had angulation of ≤ 70°. There were 26 cases with aortic dissection and 54% of these had a true lumen of ≤ 26 mm. CONCLUSION Successful fenestrated/branched stent graft repair of TAAAs requires adequate landing zones, cannulation of visceral arteries and suitable diameter access vessels. 60% of TAAAs studied were suitable for branched/fenestrated stent graft repair but 40% of TAAAs were unsuitable; aortic angulation, visceral vessel ostial stenosis and dissection true lumen diameter were the principle issues. Development in stent technology may address these anatomical challenges.


Journal of Endovascular Therapy | 2004

Relationship of Matrix Metalloproteinases and Macrophages to Embolization during Endoluminal Carotid Interventions

Colin Bicknell; David H. Peck; Nawar A. Alkhamesi; Mark G. Cowling; Martin Clark; Robert Goldin; Rodney A. Foale; Michael P. Jenkins; J.H.N. Wolfe; Ara Darzi; Nicholas Cheshire

Purpose: To investigate if relationships exist among macrophage infiltration, plasma matrix metalloproteinase (MMP) levels, and the number of emboli generated during endoluminal carotid interventions. Methods: Carotid endarterectomy specimens excised as intact cylinders (n=27) were subjected to a standardized angioplasty procedure under radiological guidance in an ex vivo pulsatile flow model. Emboli collected in distal filters were counted and sized using microscopy. Preoperative plasma gelatinase activity was determined by gelatin zymography and quantified using image analysis software. Levels of tissue inhibitors of metalloproteinases (TIMP) 1 and 2 were determined by ELISA. Macrophages within postangioplasty plaques were analyzed using immunohistochemical staining for CD68 antigen and graded by a blinded examiner. Statistical analysis was performed using Spearmans rank correlation. Results: The median number of emboli recorded during angioplasty was 104 (interquartile range 33.75–242.5, absolute range 13–1090). Plasma MMP-9 and MMP-2 levels correlated with emboli number (r=0.544 [p=0.003] and r=0.412, [p=0.033], respectively), while TIMP-1 and TIMP-2 levels did not. Macrophage infiltration within the plaques correlated with emboli number (r=0.722, p<0.001) and the plasma MMP-9 level (r=0.489, p=0.010). Conclusions: These data indicate that plaque macrophage infiltration may play a role in the generation of emboli during endoluminal carotid intervention, possibly via modulation of protease activity.

Collaboration


Dive into the Michael P. Jenkins's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar

R.G.J. Gibbs

Imperial College Healthcare

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

J.H.N. Wolfe

Imperial College Healthcare

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

M. Hamady

Imperial College Healthcare

View shared research outputs
Top Co-Authors

Avatar

Ara Darzi

Imperial College London

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge