Biomedical subjects

Nicholas J Morrissey

Publications and source records attributed to Nicholas J Morrissey.

30 records · Page 2Linked to original sources

PubMed2003

Duplex ultrasonography and its impact on providing endograft surveillance.

Increasingly, aortic aneurysms are being repaired using endoluminal grafting techniques. Complications of such surgery include persistent endoleaks, continued growth of the aneurysm and migration or thrombosis of the device. Consequently, patients undergoing endovascular repair must be under rigorous surveillance postoperatively. Spiral computed tomography scanning is the test of choice to assess the integrity of the repair, but frequent scanning subjects the patient to repeated doses of radiation and nephrotoxic contrast agents. Duplex ultrasound has long been used to diagnose the presence of aortic aneurysm and may be an appropriate tool for monitoring endovascular grafts. However, the wide variability in sensitivity, specificity, positive and negative predictive values, and accuracy rates described in the literature reflect the fact that many problems still exist with this technique. Until these difficulties can be resolved, duplex ultrasonography is best used in conjunction with spiral computed tomography.

Aortic Aneurysm, Abdominal↗

PubMed2003

Endovascular treatment of abdominal aortic aneurysms.

Minimally invasive endovascular techniques for the treatment of abdominal aortic aneurysm have significantly reduced its morbidity compared to that following standard surgical repair. Moreover, patients with extensive comorbid medical illnesses, for whom standard operative repair is contraindicated may be successfully treated using endovascular means. The full limitations and indications for use of endovascular grafts have not yet been fully defined. The effectiveness of commercially fabricated devices is currently being evaluated. This article describes the general principles of use for endovascular devices for the repair of abdominal aortic aneurysms and details the features of the devices currently in use, as well as the typical results.

Aortic Aneurysm, Abdominal↗

PubMed2002

A multicenter experience with the Talent endovascular graft for the treatment of abdominal aortic aneurysms.

OBJECTIVE: The Talent endovascular graft has been used in the treatment of abdominal aortic aneurysms (AAAs) in more than 13,000 patients worldwide. However, information regarding the results of its use has been limited. This report describes the experience with 368 patients with AAAs who underwent treatment at four medical centers as part of an investigator-sponsored investigational device exemption trial. METHODS: Patients with AAAs were enrolled at four sites during a 32-month period from January 1999 to July 2001. All patients underwent treatment for infrarenal AAA with the Talent endovascular graft. Repair was performed with transrenal stent fixation under epidural (362/368 patients; 98.3%), local (4/368 patients; 1.1%), or general (2/368 patients; 0.5%) anesthesia. The average diameters were: maximum aortic aneurysm, 6.2 +/- 1.2 cm; proximal aortic fixation site, 2.6 +/- 0.4 cm; and distal iliac fixation site, 1.4 +/- 0.6 cm. Bifurcated grafts were used in 276 of 366 patients (75%), aortouniiliac in 57 of 366 patients (16%), and tube aortoaortic in 33 of 366 patients (9%). Multiple comorbid medical conditions were present in all patients (average, 4.7 conditions/patient). The mean age was 75.8 years, and 85% of the patients were male. Follow-up period ranged from 2 to 33 months (mean, 7.3 months). RESULTS: Endovascular graft deployment was accomplished in 366 of 368 patients. In the 263 patients followed for at least 6 months after endovascular repair, AAA diameter decreased by 5 mm or more in 83 patients (32%); diameter remained unchanged (change < 5 mm) in 157 patients (60%) and increased by 5 mm or more in 23 patients (8.7%). Major morbidity occurred in 46 of 368 patients (12.5%), and minor morbidity occurred in 31 of 368 (8.4%). The 30-day mortality rate was 1.9%. Secondary procedures were performed in 32 patients (8.7%). Late rupture occurred in two patients, and late deaths unrelated to AAA occurred in 32 patients (8.7%) during the follow-up period. The primary technical success rate for all patients was 93.4%. The 30-day primary procedural success rate was 73.3%. The 30-day secondary procedural success rate was significantly higher at 85.8%. Computed tomographic scan was performed within 1 month after surgery in 349 patients. An endoleak was present in 43 of 349 patients (12.3%). These endoleaks were comprised of 10 attachment site (type I; 2.9%), 31 retrograde side-branch (type II; 8.9%), and two transgraft (type III; 0.6%). CONCLUSION: These midterm findings show a high degree of technical and procedural success achieved in a patient population with extensive comorbid medical illnesses with low perioperative morbidity and mortality rates. Further follow-up study will be necessary to determine the effectiveness of the Talent endograft for the long-term treatment of AAA.

Aged↗

PubMed2002

Failure of endovascular aortoaortic tube grafts: a plea for preferential use of bifurcated grafts.

OBJECTIVE: Aortoaortic tube graft repair was the first technique used for the endovascular treatment of abdominal aortic aneurysms (AAAs). However, progressive changes in the morphology of the distal aortic neck may be responsible for procedural failure. This study examines the use of aortoaortic tube prostheses and analyzes the factors that contributed to their failure and the methods used for their subsequent repair. METHODS: During a 7-year period, 462 patients with abdominal aortic aneurysms underwent endovascular aortic aneurysm repair. Of these, 65 patients (14%) underwent treatment with aortoaortic tube endoprostheses. Aortoaortic tube prostheses used included Talent (n = 44) (Medtronic-Worldmedical, Sunrise, Fla), Vanguard (n = 8) (Boston Scientific, Natick, Mass), EVT/Ancure (n = 4) (Guidant, Menlo Park, Calif), and physician-fabricated (n = 9). All the tube graft procedures were performed in the operating room with fluoroscopic guidance. The average age of patients for aortoaortic tube grafts was 74.5 years, and 48 of the patients were men. Failure was defined as aneurysm expansion, any type I endoleak, or type II endoleak persistent after 6 months. RESULTS: No aneurysm ruptures or perioperative deaths were seen. Retrograde aneurysm perfusion from lumbar or inferior mesenteric arteries (type II endoleak) that persisted beyond 6 months was present in three patients. Proximal attachment site endoleaks were present in two patients. No distal implantation site endoleaks were present within 1 month of the initial endovascular repair; however, endoleaks at the distal attachment site developed in 12 patients subsequently and included all graft types (Talent, n = 6; Vanguard, n = 2; Ancure/EVT, n = 1; physician-fabricated, n = 3). The average time interval to failure was 12.9 months. Preoperative distal aortic neck length showed a significant correlation with the subsequent development of distal endoleak (endoleak, 16.6 +/- 6.8 versus no endoleak, 23.3 +/- 9.6; P =.03). Preoperative distal aortic neck diameter, however, did not show significance (23.8 +/- 5.2 versus 22.6 +/- 4.7; P = not significant). CONCLUSION: Endovascular aortoaortic tube grafts are vulnerable to failure even when initial exclusion of the aneurysm is successful. A significant association is seen between distal neck length and eventual failure. Because of the propensity toward eventual failure, the use of aortoaortic tube grafts in the infrarenal aorta cannot be recommended for typical fusiform aneurysms, even when an adequate distal neck appears to be present.

Aged↗

PubMed2002

Transrenal bare stents in endovascular treatment of abdominal aortic aneurysms.

Endovascular stent-graft (EVSG) repair of abdominal aortic aneurysms (AAA) has continued to evolve since its introduction in 1991. The ability to secure a stent-graft in the suprarenal aorta with an uncovered proximal stent is felt by many to improve the overall fixation of the device and decrease the risk of migration and endoleak. While preliminary evidence suggests that type I endoleaks may be less frequent when transrenal bare stents are used, this has yet to be conclusively shown. Of obvious concern is the risk of renal parenchymal damage or diminished blood flow following placement of a bare stent across the renal artery ostia. Numerous small series have shown little or no risk of significant renal impairment at intermediate length of follow-up after transrenal stent placement. The presence of a stent across the renal artery orifice does not appear to interfere with later interventions on that artery, such as angioplasty and stenting.

Aortic Aneurysm, Abdominal↗

PubMed2002

Effect of mesenteric ischemia/reperfusion on spinal cord injury following transient aortic occlusion in rabbits.

PURPOSE: To investigate in a rabbit model if prolonged periods of mesenteric ischemia followed by reperfusion may affect the rate of neurological complications. METHODS: An infrarenal aortic snare, which consisted of a Silastic vessel loop whose ends were passed through plastic tubing, was placed in 50 male New Zealand white rabbits. In 40 of these animals, a similar but smaller device was placed around the superior mesenteric artery (SMA); all devices were exteriorized to allow vessel occlusion in the awake animal. The aorta was occluded for 12 minutes in the 10 control and 40 experimental animals, but the experimental rabbits also had occlusion of the SMA for varying intervals: 10 minutes (group 1), 12 minutes (group 2), and 18 minutes (group 3). To assess the hemodynamic effects of aortic and aortic/SMA occlusion, select control and test animals had blood pressure and heart rate monitoring via indwelling carotid catheters during the occlusion periods. The animals were euthanized, and spinal cords from paralyzed and normal rabbits were examined histologically RESULTS: Neurological deficit occurred in 20% of controls and in 70%, 80%, and 100% in the experimental groups, respectively. There were no significant differences in systemic blood pressure at any time point during occlusion and reperfusion in the monitored control or test animals. There was no evidence of thrombosis of spinal arteries on histological analysis, nor was there evidence of bowel infarction at the time of sacrifice in animals undergoing combined aortic/SMA occlusion. CONCLUSIONS: Mesenteric ischemia/reperfusion worsens the neurological outcome in animals undergoing transient aortic occlusion. This observation is independent of hemodynamic influences and not the result of spinal artery thrombosis.

Analysis of Variance↗

PubMed2002

Predicting iliac limb occlusions after bifurcated aortic stent grafting: anatomic and device-related causes.

OBJECTIVE: Graft limb occlusion may complicate endovascular abdominal aortic aneurysm repair. The precise etiologic factors that contribute to the development of these graft limb thromboses have not been defined. We evaluated our experience with bifurcated aortic endografts to determine factors that may predict subsequent limb thrombosis. The management of the thrombosed limbs and the results after treatment were also investigated. METHODS: During a 4-year period, 351 patients with aortic aneurysms underwent treatment with bifurcated endografts (702 graft limbs at risk). These 351 bifurcated devices included AneuRx (Medtronic, Minneapolis, Minn; n = 35), Ancure (Guidant, Menlo Park, Calif; n = 8), Gore (W.L. Gore & Associates, Sunnyvale, Calif; n = 25), Talent (World Medical, Sunrise, Fla; n = 255), Teramed (Teramed, Minneapolis, Minn; n = 10), and Vanguard (Boston Scientific Vascular, Natick, Mass; n = 18). Details regarding the type of device, mechanism of deployment, and aortoiliac artery anatomy were collected prospectively and analyzed. Graft limbs were analyzed for diameter, use of additional endograft iliac extensions, deployment in the external iliac artery, and endograft to vessel oversizing. Follow-up included physical examination, duplex ultrasonography, and spiral computed tomographic scans at 1 month, 6 months, and 12 months and annually thereafter. The follow-up period ranged from 2 to 54 months, with a mean follow-up period of 20 months. RESULTS: Twenty-six of 702 limbs (3.7%) had an occlusion develop. The risk of limb thrombosis was associated with a smaller limb diameter. Mean graft limb diameter was 14 mm in the occluded population, and patent limbs had a mean diameter of 16 mm. Thrombosis occurred in 16 of 291 limbs (5.5%) that were 14 mm or less and in 10 of 411 limbs (2.4%) that were greater than 14 mm (P =.03). Extension of a graft to the external iliac artery was performed in 96 of the 702 limbs. Eight of these 96 limbs (8.3%) had thrombosis develop as compared with 18 of 606 (3.0%) that extended to the common iliac artery (P =.01). No significant association was present between limb thrombosis and the contralateral or ipsilateral side of a device, the configuration of the iliac graft limb end (closed web, open web, or bare spring), or the degree of iliac graft limb oversizing. AneuRx, Ancure, Vanguard, and Talent grafts each sustained limb occlusions, with no occlusions seen among the Gore and Teramed devices. No significant increased risk of graft limb thrombosis was observed in unsupported grafts (1/16; 6.3%) versus supported grafts (25/686; 3.6%; P = not significant). Thromboses occurred between 1 day and 23 months after surgery. Thirteen of the 26 thromboses (50%) occurred within 30 days of surgery. Presenting symptoms were mild to moderate claudication in eight patients (30.8%), severe claudication in 16 patient (61.5%), and paresthesia and rest pain in two patients (7.7%). Eighteen of 26 patients (69.2%) eventually needed intervention to reestablish flow to the occluded limb, including thrombolysis and stenting in two patients (7.7%), axillary femoral bypass in one patient (3.8%), femoral-femoral bypass in 13 patients (50.0%), and axillary-bifemoral bypass in two patients (7.7%). All patients with mild to moderate symptoms under observation had improvement in symptoms with no further interventions necessary. All revascularizations were successful in relieving symptoms. CONCLUSION: Graft limb occlusion is a recognized complication of endovascular treatment of abdominal aortic aneurysms that may be associated with smaller graft limb diameter and extension to the external iliac artery. Occlusions usually necessitate additional intervention for resolution of ischemic symptoms. The use of small diameter grafts should be avoided when possible to reduce the risk of graft limb occlusions.

Aortic Aneurysm, Abdominal↗

PubMed2002

Abdominal aortic aneurysmorrhaphy and cholelithiasis in the era of endovascular surgery.

The incidence of acute cholecystitis complicating standard abdominal aortic aneurysm (AAA) repair has been reported between 0.3 and 18 per cent. This has prompted considerable debate regarding the management of cholelithiasis discovered incidentally during open aortic reconstruction. This study seeks to determine the incidence of cholelithiasis and acute cholecystitis after endovascular AAA repair and evaluate options for management. Between February 1996 and October 2001 492 patients underwent endovascular AAA repair. All the procedures were performed in the operating room under fluoroscopic guidance. Epidural (98.9%), local (0.5%), or general (1.7%) anesthesia was used during these cases. The incidence of cholelithiasis and acute cholecystitis was evaluated by CT scan and abdominal ultrasound. Serum measurements of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total and direct bilirubin, and amylase were performed and clinical assessment was conducted at 1, 6, and 12 months postoperatively and annually thereafter. The mean age of these patients was 76.6 years; 84% were male. Comorbid medical conditions were present in all patients (average 3.5 conditions/patient). Follow-up ranged from 2 to 35 months (mean 12.8 months). Endovascular stent graft deployment was successful in 486 of the 492 patients (98.8%). Six patients were converted to standard open repair because of inability to achieve successful endovascular aneurysm repair. The perioperative major morbidity rate was 14.9 per cent. Minor morbidity rate was 8.5 per cent. The perioperative mortality rate was 1.9 per cent. No deaths were related to biliary disease. Cholelithiasis was identified in 64 (13%) patients preoperatively. One of 64 patients with a prior Billroth II reconstruction for peptic ulcer disease developed jaundice 8 days after AAA repair as a result of choledocholithiasis that required surgical repair. One patient without gallstones developed acute acalculous cholecystitis on postoperative day 16 as determined on pathologic analysis of the gallbladder. A third patient who had gallstones identified on preoperative CT scan developed calculous cholecystitis 16 months after endovascular AAA repair. These two patients underwent uncomplicated laparoscopic cholecystectomy and recovered uneventfully. The incidence of postoperative symptomatic cholelithiasis is 1.6 per cent (one of 64). The incidence of postoperative acute cholecystitis was 0.2 per cent (one of 486) and was unrelated to the presence of gallstones. The incidence of delayed symptomatic cholelithiasis was 1.6 per cent (one of 64). Endovascular repair of AAA does not appear to predispose the patient to the development of symptomatic cholelithiasis during the perioperative period. Therefore a preoperative or intraoperative diagnosis of cholelithiasis does not necessitate cholecystectomy in the setting of planned endovascular AAA repair. Patients who develop cholecystitis after endovascular AAA repair may be effectively treated by standard laparoscopic techniques.

Acute Disease↗

PubMed2002

Intentional internal iliac artery occlusion in endovascular repair of abdominal aortic aneurysms.

Endoluminal grafting of aortoiliac aneurysms is an evolving technology. Since many lesions involve part of all of the common iliac arteries, it may be necessary to cover the internal iliac (hypogastric) arteries. Since the internal iliac arteries are important for flow to pelvic organs and perhaps the colon, their sacrifice may not be innocuous, especially since reimplantation of the inferior mesenteric artery is not possible during endovascular aneurysm repair. Most series reflect the relative safety of unilateral internal iliac artery sacrifice. Bilateral hypogastric artery sacrifice, especially if not staged temporally, may cause more significant complications. The incidence of claudication and impotence remains significant, prompting some to recommend revascularization of at least one internal iliac artery at the time of aneurysm repair in order to preserve one of these important vessels. Such an internal iliac artery bypass can be simply performed during endovascular aneurysm repair. The development of larger, more precisely deployed iliac limbs as well as the development of branched devices should decrease the need for internal iliac artery sacrifice.

Angiography↗

PubMedDate not supplied

Recent advances in peripheral angioplasty and stenting.

Utilization of percutaneous interventions for arterial and venous occlusive lesions continue to increase. With the progression of the technology supporting these therapeutic measures, the results of these interventions may be expected to improve. In general, a comparison of techniques for revascularization demonstrates similar initial technical success rates for surgery and percutaneous transluminal angioplasty. Angioplasty is often associated with lower procedural morbidity and mortality rates. Conversely, surgery frequently provides greater long-term patency. Late failure of percutaneous therapies may often be treated successfully with reintervention, however. The continued accumulation of experience with PTA and stenting will ultimately define its role in the management of occlusive disease.

Angioplasty, Balloon↗

PubMedDate not supplied

Multimodal therapy for acute and chronic venous thrombotic and occlusive disease.

Critical deep venous thrombosis and occlusion constitutes a small percentage of patients with venous disease. However, these patients exhibit severe symptomatology including pain and extensive edema that may progress to limb- or life-threatening complications such as phlegmasia cerulea dolens and superior vena cava syndrome. This paper reviews the different multimodal percutaneous interventions currently available for the treatment of complex critical venous thrombotic and occlusive disease.

Acute Disease↗

PubMedDate not supplied

Aortoenteric fistula: a late complication of endovascular repair of an inflammatory abdominal aortic aneurysm.

Endovascular repair provides a reasonable alternative to open repair for the treatment of abdominal aortic aneurysms in select cases. Although the endovascular approach may be preferable for inflammatory aneurysms, aggressive surveillance is needed to monitor for long-term complications. A 61-year-old man underwent endovascular exclusion of a symptomatic inflammatory abdominal aortic aneurysm with an AneuRx bifurcated aortic prosthesis. He presented with gastrointestinal bleeding 51/2 months later and was found to have an aortoenteric fistula involving the third portion of the duodenum. The aneurysm had expanded significantly at the proximal neck. The patient underwent successful removal of the device, aortic ligation, and extraanatomic bypass. Aortoenteric fistula is a rare but now established complication of endovascular aneurysm repair. The pathophysiology in these cases remains unclear. The presence of inflammation and endoleak may predispose to further aneurysmal degeneration.

Angioplasty↗