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Biomedical subjects

M P Colgan

Publications and source records attributed to M P Colgan.

At least 19 recordsLinked to original sources
PubMed2001

Arcuate-legged nonpenetrating vascular closure staples (VCS): early experience.

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.

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PubMed2001

Endoluminal stent grafts in the management of infrarenal abdominal aortic aneurysms: a realistic assessment.

OBJECTIVES: 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. MATERIAL AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.

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PubMed2001

Ultrasound guided human thrombin injection. A new modality in the management of femoral artery pseudo-aneurysms.

OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

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PubMed2000

Suprarenal mycotic aneurysm exclusion using a stent with a partial autologous covering.

PURPOSE: 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. METHODS AND RESULTS: 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. CONCLUSIONS: Stent-graft repair may be able to lessen the invasiveness and reduce the morbidity associated with treatment of mycotic aortic aneurysms.

Aneurysm, Infected↗
PubMed2000

Endovascular management of rare sciatic artery aneurysm.

PURPOSE: To present a rare case of complete persistent sciatic artery aneurysm successfully treated by coil embolization and to suggest a new classification for this anomaly that encompasses both clinical and pathological factors. METHODS AND RESULTS: A 77-year-old female presented with sudden onset of sharp, throbbing left thigh and foot pain. A nontender 10.0- x 7.0-cm pulsatile mass was found over the inferolateral aspect of the left buttock on examination in the right lateral decubitus position. Angiography demonstrated a 6.9-cm sciatic artery aneurysm with the distal sciatic artery completely thrombosed. Before planned bypass grafting, the aneurysm and distal segment of the internal iliac artery were successfully embolized with coils through a left percutaneous approach. The patient's symptoms resolved with no deterioration in limb perfusion, and further revascularization was unnecessary. Postembolization imaging showed complete occlusion of the aneurysm, which has continued for 19 months. CONCLUSIONS: The application of endovascular techniques and surgical revascularization procedures provides numerous management options for the treatment of an aneurysmal persistent sciatic artery. This case demonstrates that clinical evaluation between staged procedures may obviate the need for further intervention.

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PubMed2000

Tibial and peroneal artery bypasses using polytetrafluoroethylene (PTFE) with an interposition vein cuff.

UNLABELLED: The combined results of femoro-distal bypasses using prosthetic material with vein cuffs from two separate vascular units is presented. METHOD: Over the last five years, 89 infrainguinal bypasses using polytetrafluoroethylene (PTFE) with a distal interposition vein cuff to a tibial artery have been performed in two centres. All operations were for critical limb ischaemia. The mean age was 72 years (47-90), there were 46 males and 43 females, 27 of whom were diabetic. Twenty-eight patients had a history of angina and/or previous myocardial infarct. The median follow-up was 12 months (0-68 months). RESULTS: During the follow-up period there were 28 deaths, 35 major limb amputations and 44 graft failures. The graft patency rates at 12 and 24 months were 50 and 32%, and limb salvage rates were 53 and 44%, respectively. The patient survival rates were 66 and 61%, respectively. CONCLUSION: The authors believe that the likely improvement in pain free quality of life the patient may enjoy with a successful bypass shifts the balance in some individuals towards bypass surgery using PTFE with a vein cuff to a tibial artery when such an option is possible.

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PubMed1999

Outcome of the first 100 femoropopliteal angioplasties performed in the operating theatre.

OBJECTIVES: To examine the factors influencing outcome and restenosis in an initial series of 100 infrainguinal angioplasties. DESIGN: Prospective study of angioplasties of the superficial femoral and popliteal arteries performed over a 42-month period. MATERIALS AND METHODS: One hundred consecutive angioplasties in 96 patients performed in the operating theatre between January 1993 and June 1996 were followed prospectively with clinical, ABI, and duplex assessment. Forty-four procedures were for disabling claudication and 56 for critical ischaemia. Stents were deployed in 30 limbs. RESULTS: Angioplasty was successful in 84 of 100 limbs. Cumulative patency of the entire group at 3, 6, 12 and 18 months was 78%, 60%, 53%, and 49% respectively, while excluding initial failures, gave patencies of 95%, 69%, 63%, and 58%, respectively. Claudicants with a 1-year patency of 64% did significantly better than patients with critical ischaemia (44% p < 0.05). Angioplasties performed during the initial 21 months had a 1-year patency of 42%, while those performed in the final 21 months had a 74% patency (p = N.S.). The patency for stented arteries was 66% vs. 49% for angioplasty alone (p = N.S.). The 2-year limb salvage rate was 91% in patents with critical ischaemia. Forty-six per cent of restenoses were asymptomatic. CONCLUSIONS: The results suggest that while angioplasty is useful in treating infrainguinal arterial disease, there is a learning curve, resulting in a high restenosis rate for occlusive and multilevel disease, while concomitant placement of stents may be beneficial.

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PubMed1999

Fifteen-year experience of transperitoneal management of inflammatory abdominal aortic aneurysms.

OBJECTIVES: to assess the long-term outcome of patients with inflammatory abdominal aortic aneurysms. MATERIALS AND METHODS: over a fifteen-year period 598 cases of abdominal aortic aneurysm were treated and, of these, 32 cases (5.3%) were inflammatory in nature. The diagnosis was made on preoperative (CT) computed tomography in fifteen cases. Twenty-six patients were symptomatic on presentation and ten cases were repaired on an emergency basis. Only six were repaired electively. The transabdominal transaortic approach without dissection on the nearby adherent structures was used routinely. RESULTS: there was one postoperative death from a respiratory arrest leading to a thirty-day mortality of 3.1%. Early graft thrombosis occurred in three cases (9.3%) and all underwent successful thrombectomy. Colonic ischaemia was encountered in one patient who later developed an aortoenteric fistula. Two patients suffered a non-fatal myocardial infarction postoperatively leading to an overall morbidity of 18.7%. CONCLUSIONS: patients with inflammatory aortic aneurysms fare worse than patients with aortic aneurysms in general. Preoperative suspicion assists in planning surgery. We believe that the transperitoneal approach with an anterolateral aortotomy and minimal dissection of adherent structures offers excellent results in dealing with this difficult group of patients.

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PubMed1999

Aorto-left renal vein fistula: is there a place for endovascular management?

PURPOSE: To describe the endovascular treatment of an aorto-left renal vein fistula. METHODS AND RESULTS: A 77-year-old man with multiple comorbidities presented with low back pain, hematuria, cyanosis, and a pulsatile abdominal mass. Imaging confirmed a 7-cm abdominal aortic aneurysm with a contained rupture into the left renal vein. Owing to the patient's high surgical risk, a Talent Endoluminal Stent-Graft was implanted to satisfactorily exclude the aneurysm. Hemodynamic stability and normal renal function were restored; however, continued perfusion of the sac prompted an attempt to percutaneously repair the renal vein defect. This effort failed, so open laparotomy was necessary. CONCLUSIONS: Although total endovascular management was not successful in this case, the initial use of a minimally invasive approach allowed the patient's clinical status to improve and lower the risk of subsequent surgery.

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PubMed1998

Popliteal aneurysms: a 10-year experience.

BACKGROUND: Popliteal aneurysms account for 70% of peripheral arterial aneurysms and, if untreated, pose a serious threat to the affected limb. Debate continues about the best form of treatment especially for asymptomatic lesions. METHOD: We reviewed the computer records and charts of patients seen at this department with a diagnosis of popliteal aneurysm over the last 10 years. Patients who had not been seen within the last year were followed-up through their G.P. RESULTS: Twenty-four patients (M 23/F 1) presented with 40 popliteal aneurysms. The mean age was 63.5 +/- 9 years. Symptoms were present in 23 of the affected limbs while 17 were asymptomatic. Thirty were treated surgically and 10 followed with regular ultrasound. The mean diameter of the repaired aneurysms was 3.3 +/- 1 cm. Aneurysms < 2 cm were more likely to be asymptomatic. No limbs were lost in patients undergoing elective repair of popliteal aneurysms. The secondary patency and limb salvage rates at 3 years were 84% and 96% respectively. Conservative management of asymptomatic lesions < 2 cm was not complicated by the development of symptoms. CONCLUSIONS: Elective repair of popliteal aneurysms by exclusion and bypass is a safe, effective and durable technique. Small asymptomatic lesions can be safely managed with close follow-up.

Aneurysm↗
PubMed1998

Recurrent varicose veins.

Recurrence of varicose veins after treatment has been reported as being between 7% and 65%. During the five month period from August to December 1993, 400 operations on 265 patients were performed for varicose vein disease. Of these, 53 patients had presented with recurrent vein disease in 72 limbs (18%). All patients underwent Duplex scanning of their deep and superficial systems and sites of venous incompetence were identified. The sapheno-femoral junction (SFJ) was found to be incompetent in 52 limbs, of which 31 had previously undergone flush ligation. Sapheno-popliteal junction (SPJ) was incompetent in 33 limbs, while the long saphenous vein (LSV) was found to be incompetent in 67 cases. There were no major complications in this group. Minor complications occurred in 10 cases (14%), mainly in the form of thigh paraesthesia. The more common causes of recurrent disease have been identified and therefore, it should be possible to reduce its incidence. Duplex scanning is essential for any unit dealing with recurrence.

Adult↗
PubMed1997

Alpha 2C-adrenoceptors mediate contractile responses to noradrenaline in the human saphenous vein.

We have investigated the subtype of alpha 2-adrenoceptor mediating isometric contractions of human saphenous vein in comparison with alpha 2-adrenoceptor ligand binding sites. Postjunctional alpha 2-adrenoceptors in the human saphenous vein were investigated in terms of the ability of alpha 2-adrenoceptor antagonists to shift the contractile potency of noradrenaline. The following antagonists were employed (potencies, pKB, in human saphenous vein in parentheses): chlorpromazine (6.98 +/- 0.24), BDF 8933 (7.60 +/- 0.06), prazosin (6.62 +/- 0.15), ARC 239 (7.19 +/- 0.15), yohimbine (7.23 +/- 0.09), HV 723 (7.52 +/- 0.14), WB 4101 (7.90 +/- 0.06), SKF 104078 (6.55 +/- 0.08), BRL 44408 (5.72 +/- 0.21). Antagonist potency at postjunctional alpha 2-adrenoceptors was correlated with antagonist affinity at alpha 2-adrenoceptor ligand binding sites in membranes of human platelet (alpha 2A), rat kidney (alpha 2B) and Sf9 cells expressing human recombinant receptors (alpha 2C), labelled with [3H]yohimbine. The correlation with the postjunctional alpha 2-adrenoceptor mediating contraction of the human saphenous vein was best for the human recombinant alpha 2C-adrenoceptor ligand binding site (r = 0.92, n = 8, P < 0.001), as compared to correlations with the alpha 2B-adrenoceptor ligand binding site of rat kidney (r = 0.62, n = 8, n.s.) and with the alpha 2A-adrenoceptor ligand binding site of human platelet (r = 0.23, n = 8, n.s.). It is concluded that the functional postjunctional alpha 2-adrenoceptor mediating contractions of the human saphenous vein closely resembles the human recombinant alpha 2C-adrenoceptor ligand binding site.

Adrenergic alpha-2 Receptor Agonists↗
PubMed1997

Lower extremity bypass for critical ischemia using synthetic conduit and adjuvant vein cuff.

The use of an interposition cuff of vein placed at the distal anastomosis between synthetic bypass conduit and outflow vessel has been advocated to improve patency of lower extremity bypass grafts. Over a three-year period we have performed 43 such bypass procedures: to the above knee popliteal artery (n = 3); below knee popliteal (n = 13), and infrapopliteal arteries (n = 27). There were 20 females and 23 males having a mean age of 70 years (48-84 years). Fifteen patients were hypertensive, 15 were diabetic, and 25 had a history of tobacco use. All cases required limb salvage for rest pain (n = 25), gangrene (n = 10), or ulceration (n = 8) in the absence of suitable autologous vein. Nineteen operations followed a previous failed bypass. Patients were reviewed at six-month intervals. The operative mortality was 8% and two-year primary and secondary patency were 40% and 55%, respectively. Cumulative patency rates were better for first-time grafting procedures than for patients who had undergone previous attempts at limb salvage (60% versus 22%). Two-year limb salvage was 60%. During the same time period, two-year primary and secondary patency rates were 54% and 67%, respectively for autogenous vein. Although the numbers are small these results support the use of an adjuvant vein cuff when employing synthetic grafts. A prospective study of vein versus synthetic graft plus cuff should be undertaken.

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PubMed1995

Skin closure and the incidence of groin wound infection: a prospective study.

Groin wound infection is a dreaded complication of vascular surgery and may jeopardize an underlying graft. A variety of skin closures have been used and the object of this study was to prospectively determine the relationship between skin closure and wound infection. One hundred fourteen consecutive patients (70 men and 44 women) undergoing bypass surgery with a groin incision (n = 173) were randomly assigned to skin closure with subcuticular Maxon, interrupted nylon, continuous nylon, or clips following a standard two-layer closure of subcutaneous tissue. Fourteen (12%) patients had diabetes and 50 (44%) had digital ulceration and gangrene. Aortofemoral bypass was performed in 25% of the patients and infrainguinal bypass in the remaining 75%. Perioperative wound cultures were obtained before closure. Wounds were inspected and cultures repeated on postoperative days 3, 5, 7, 10, and 14. Infection was defined as a positive culture. Groin wound infection occurred in 3% of the population and graft infection in 0.6%. The type of suture did not influence the incidence of infection. This study failed to demonstrate a significant difference in the incidence of wound infection with the use of different suture materials. We conclude that suture material should be selected on the basis of surgeon preference and costs.

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PubMed1995

Arterial closing pressure correlates with diastolic pseudohypertension in the elderly.

BACKGROUND: Pseudohypertension has frequently been reported in the elderly population, with the diastolic measurement being the most frequent source of error. There is no satisfactory noninvasive method of calculating the error in the blood pressure reading. We investigated the role of arterial closing pressure in the diagnosis of diastolic pseudohypertension. METHODS: Indirect and direct blood pressure were measured in 24 elderly patients. Brachial artery closure was visualized by ultrasound in all subjects. Arterial closing pressure (ACP) was recorded as zero if the vessel was seen to close spontaneously when it was isolated from central arterial pressure. If the vessel did not close spontaneously, a water cuff was applied externally over the artery and the additional pressure required to close it was recorded. RESULTS: Diastolic pseudohypertension was noted in 8 subjects. Spontaneous closure of the brachial artery occurred in the 16 without pseudohypertension; i.e., ACP = 0. Additional pressure of the water cuff (range: 30-158 mm Hg) was required to collapse the artery (ACP) in those with diastolic pseudohypertension. ACP correlated with the extent of diastolic pseudohypertension (range: 5-17 mm Hg); r = .85, p < .001). CONCLUSION: We propose that ACP may be used to diagnose the presence and extent of pseudohypertension.

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PubMed1995

Pentoxifylline and critical leg ischemia.

The annual incidence of critical leg ischemia has been estimated at 500-1,000 patients per million population/year. In critical ischemia there is a breakdown in the microvascular flow-regulating system and inappropriate activation of the microvascular defense system, with resultant endothelial damage and activation of platelets and leukocytes, which leads to further damage of the capillary network. The mainstay of treatment until recently has consisted of interventional procedures. However, these are not always feasible and are not without significant mortality and morbidity. Therefore, attention has been directed towards pharmacologic management. Pentoxifylline inhibits leukocyte aggregation and activation, and improves red cell deformability and oxygen release to tissue. On the basis of these properties, several pilot studies were undertaken, and most have confirmed the benefits of pentoxifylline in the management of critical ischemia. These positive results led to the initiation of a multicenter, double-blind, placebo-controlled study of intravenous pentoxifylline in the acute management of critical ischemia. Results showed a significant reduction in rest pain with pentoxifylline, and outcome was not influenced by various prognostic factors. Research to date suggests that pentoxifylline could have a definite role in the management of patients with critical ischemia.

Humans↗
PubMed1994

The comparison of type of incision for transperitoneal abdominal aortic surgery based on postoperative respiratory complications and morbidity.

Equal access to the abdominal aorta can be attained through midline and transverse abdominal incisions. The surgical literature suggests that transverse incisions cause less postoperative pain and morbidity. Fifty patients (10 females and 40 males, mean age 67 years) undergoing abdominal aortic surgery were randomised to a midline (n = 25) or transverse (n = 25) incision. All patients were evaluated preoperatively and postoperatively for seven days. Changes in pulmonary function (FVC and FEV1), time to open and close the incision, analgesia used (morphine mg/kg/h), clinical or X-ray evidence of chest infection, and the duration of ICU stay were recorded. In the transverse group there was a reduction in the incidence of chest complications (20% vs. 28%, p = ns) and these incisions took longer to open (13.9 +/- 4.6 vs. 9.9 +/- 5.1, p < 0.05), but overall there was no significant difference between any other parameter in the two groups. Our results show no statistically significant difference in morbidity or analgesia consumption following transverse or midline abdominal incisions and we conclude that the type of incision used can be left to the surgeon's preference.

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