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Biomedical subjects

J P Carpenter

Publications and source records attributed to J P Carpenter.

At least 19 recordsLinked to original sources
PubMed2006

Structural MRI of carotid artery atherosclerotic lesion burden and characterization of hemispheric cerebral blood flow before and after carotid endarterectomy.

Collateral circulation plays a major role in maintaining cerebral blood flow (CBF) in patients with internal carotid artery (ICA) stenosis. CBF can remain normal despite severe ICA stenosis, making the benefit of carotid endarterectomy (CEA) or stenting difficult to assess. Before and after surgery, we assessed CBF supplied through the ipsilateral (stenotic) or contralateral ICA individually with a novel hemisphere-selective arterial spin-labeling (ASL) perfusion MR technique. We further explored the relationship between CBF and ICA obstruction ratio (OR) acquired with a multislice black-blood imaging sequence. For patients with unilateral ICA stenosis (n = 19), conventional bilateral labeling did not reveal interhemispheric differences. With unilateral labeling, CBF in the middle cerebral artery (MCA) territory on the surgical side from the ipsilateral supply (53.7 +/- 3.3 ml/100 g/min) was lower than CBF in the contralateral MCA territory from the contralateral supply (58.5 +/- 2.7 ml/100 g/min), although not statistically significant (p = 0.09). The ipsilateral MCA territory received significant (p = 0.02) contralateral supply (7.0 +/- 2.7 ml/100 g/min), while ipsilateral supply to the contralateral side was not reciprocated. After surgery (n = 11), ipsilateral supply to the MCA territory increased from 57.3 +/- 5.7 to 67.3 +/- 5.4 ml/100 g/min (p = 0.03), and contralateral supply to the ipsilateral MCA territory decreased. The best predictor of increased CBF on the side of surgery was normalized presurgical ipsilateral supply (r(2) = 0.62, p = 0.004). OR was less predictive of change, although the change in normalized contralateral supply was negatively correlated with OR(excess) (=OR(ipsilateral) - OR(contralateral)) (r(2) = 0.58, p = 0.006). The results demonstrate the effect of carotid artery stenosis on blood supply to the cerebral hemispheres, as well as the relative role of collateral pathways before surgery and redistribution of blood flow through these pathways after surgery. Unilateral ASL may better predict hemodynamic surgical outcome (measured by improved perfusion) than ICA OR.

Aged↗
PubMed2006

The Powerlink bifurcated system for endovascular aortic aneurysm repair: four-year results of the US multicenter trial.

The aim of the study was to review the results of abdominal aortic aneurysm (AAA) repair with the Powerlink Bifurcated endovascular graft, when compared with open AAA repair. A prospective, controlled, multicenter trial of the Powerlink System for endovascular abdominal repair (EVAR) was conducted at 15 sites as part of a pivotal FDA trial. Between July 2000 and March 2003, 258 patients were enrolled (192 test and 66 control patients). Stent grafts were oversized by 10-20% relative to computed tomography (CT)-based diameter measurements. All repairs were performed in the operating room through one surgically exposed femoral artery and a contralateral 9 French sheath percutaneously placed. Results were assessed using contrast-enhanced CT and plain abdominal X-rays at 1, 6, and 12 months and annually postoperatively. Mean follow-up of 36 months was available. Technical success was achieved in 97.9% of patients, with 4 failed insertions: 3 early conversions for deployment issues and one access failure. There was a significant difference in 30-day mortality between Powerlink (1%) and control (6.1%) patients and only 1 death was procedure-related (P=0.0389). Blood loss (341 mL vs 1 583 mL, P<0.0001), operative time (136 min vs 222 min, P<0.0001), Intensive Care Unit (ICU) stay (0.78 days vs 4.1 days, P<0.0001) and hospital length of stay (3.3 days vs 9.5 days, P<0.0001) were significantly less in the Powerlink cohort compared with controls. Secondary procedures have been performed on 16 patients post-implant to 48 months follow-up. At the time of the first month CT scan, endoleaks were noted in 25 patients, yielding a 30-day endoleak rate of 22.3%. Type II endoleaks predominated and there were no type III or IV endoleaks. The 4-year endoleak-free survival rate was 73%. No Type I, III or IV endoleaks were reported at 48 months post-implant. There have been no ruptures, graft fabric defects or wire fractures. Sac regression was noted in 83% of patients. Significant reduction in mean AAA diameter and volume was noted over every follow-up interval. In comparison to the 1-month post-implant CT scan, 2 patients had an increase in AAA diameter 5 mm at 48 months. The Powerlink system appears to be safe, and effectively protects patients from AAA rupture over the follow-up period. The graft and stent materials are still free from failure and fatigue. Contralateral limb access (9 Fr) facilitates graft placement in patients with disadvantaged access routes. EVAR performed with the Powerlink produces significantly less early adverse events than open AAA repair. Continued follow-up over the longer term is necessary to assure the durability of these results.

Aortic Aneurysm, Abdominal↗
PubMed2001

Endovascular AAA repair in patients with renal insufficiency: strategies for reducing adverse renal events.

Vascular imaging, usually employing nephrotoxic contrast agents is relied upon for all aspects of endovascular AAA repair causing some to consider renal insufficiency a relative contraindication. We sought to determine if endovascular AAA evaluation and repair could be successfully accomplished by minimally or non-nephrotoxic modalities. Records and results for 98 consecutive patients undergoing endovascular AAA repair were reviewed. Patients requiring dialysis preoperatively were excluded (N=3). The average volume of iodinated contrast agent employed for intraoperative imaging was 152 cc (35-420 cc). Twenty patients (20%) had baseline renal insufficiency (serum creatinine > or =1.3 mg/dl). A rise in serum creatinine above baseline was observed in 23 (24%) patients following repair; for 15 (16%) this was permanent. Creatinine rise occurred in patients with both normal (15) and abnormal (8) baseline values (P=0.09). Rise in creatinine was independent of contrast volume employed and of the use of infrarenal vs suprarenal device fixation (P>0.05). Two (2%) patients required permanent dialysis, one of which had a normal baseline creatinine and unclear etiology for renal failure, the other had a baseline creatinine of 2 and required device placement over an accessory renal artery. Strategies to minimize the use of nephrotoxic contrast for patients with renal insufficiency included the use of MRA, rather than contrast-CT for pre and postoperative imaging (7, 35%) and use of Gadolinium rather than iodinated contrast for performance of intraoperative arteriography (5, 25%). Endovascular grafts were successfully designed and implanted based upon MRA as the sole preoperative imaging modality in every case in which it was attempted (7). Mortality was not significantly different between those with and without abnormal baseline renal function (P>0.05). Adverse events (access failures, arterial injuries, blood loss, endoleaks) were not significantly correlated with baseline renal insufficiency, rise in creatinine from baseline, use of MRA or intraoperative Gadolinium angiography (P>0.05).Pre- and postoperative evaluation and performance of endovascular AAA repair can be accomplished in patients with renal insufficiency without increasing the rate of mortality or adverse events employing a strategy which minimizes the use of nephrotoxic contrast agents, relying upon Gadolinium arteriography and MRA. Endovascular grafts can be successfully planned and followed employing MRA as the sole imaging modality.

Aortic Aneurysm, Abdominal↗
PubMed2001

Balloon embolization of the internal iliac artery before aneurysm endograft deployment.

Six patients, ranging from 69 to 81 years of age, underwent iliac artery embolization with use of Detachable Silicon Balloons (DSB) 11-14 days before stent-graft repair of aneurysms. Balloons of 8.8-mm, 9.4-mm, and 9.9-mm sizes were used with 20-30 g of release force. Deployment difficulty was experienced in three cases. Five of six cases were successful, with the iliac artery remaining occluded at the time of endografting; one case required subsequent coil replacement. The average operative time for balloon embolization (75 min +/- 28) was shorter than that in 18 cases of coil embolization performed within the same time period (111 min +/- 105), but the difference was not significant (P = .21). Postoperatively, one patient (17%) reported buttock claudication after the procedure. Use of the DSB represents an alternative to use of coils for embolization of large and tortuous iliac arteries.

Aged↗
PubMed2001

Diagnosis and management of type 2 endoleaks after endovascular aneurysm repair.

Endovascular repair is a major treatment advance in patients with large infrarenal abdominal aortic aneurysms. Since the FDA approved two commercial devices 2.5 years ago, over 40,000 patients have undergone this procedure in the United States. Although we have learned a great deal, more than a few mysteries relating to the long-term performance of these devices remain. This results in never-ending surveillance protocols searching for graft failure and aneurysm expansion. One of the especially contentious issues is the management of type 2 endoleaks. Unlike other endoleaks that are related to problems with the graft and/or fixation, this type of leak occurs in patients with properly functioning devices. This is why so much controversy exists about whether or not these patients must be treated. Some advocate "watchful-waiting" intervention only when there is aneurysm expansion. Others routinely treat patients with type 2 endoleaks in an attempt to prevent expansion. As with most controversial topics, if you look carefully, there is more agreement than disagreement between the two groups. In this review, we will first describe the methods used for endoleak diagnosis and treatment. We will then review our current endoleak treatment algorithm and explain its rationale for use.

Algorithms↗
PubMed2001

Aneurysm sac pressure measurements after endovascular repair of abdominal aortic aneurysms.

OBJECTIVES: The goal of endovascular grafting of abdominal aortic aneurysms (AAAs) is to exclude the aneurysm sac from systemic pressure and thereby decrease the risk of rupture. Unlike conventional open surgery, branch vessels in the sac (eg, lumbar artery and inferior mesenteric artery [IMA]) are not ligated and can potentially transmit pressure. The purpose of our investigation was to evaluate the feasibility of various interventional techniques for measuring pressure within the aneurysm sac in patients who had undergone endovascular repair of AAAs. METHODS: Sac pressure measurements were performed in 21 patients who had undergone stent graft repair of AAAs. Seventeen of 21 patients had endoleaks demonstrated on 30-day computed tomographic (CT) scans. Access to the aneurysm sac in these patients was through direct translumbar sac puncture (5 patients), through a patent IMA accessed via the superior mesenteric artery (SMA) (9 patients), or by direct cannulation around attachment sites (3 patients). Four patients had perioperative pressure measurements obtained through catheters positioned along side of the endovascular graft at the time of its deployment. Two of these catheters were left in position for 30 hours during which time CT and conventional angiography were performed. Pressures were determined with standard arterial-line pressure transduction techniques and compared with systemic pressure in each patient. RESULTS: Elevated sac pressure was found in all patients. The sac pressure in patients with endoleaks was found to be systemic (15 patients) or near systemic (2 patients) and all had pulsatile waveforms. Elevated sac pressures were also found in patients without CT or angiographic evidence of endoleak (2 patients). Injection of the sacs in two of these patients revealed a patent lumbar artery and an IMA. CONCLUSIONS: It is possible to measure pressures from within the aneurysm sac in patients with stent grafts with a variety of techniques. Patients may continue to have pressurized AAA sacs despite endovascular AAA repair. Endoleaks transmit pulsatile pressure into the aneurysm sac regardless of the type. It is possible to have systemic sac pressures without evidence of endoleaks on CT or angiography.

Angioplasty, Balloon↗
PubMed2001

Gender-related differences in infrarenal aortic aneurysm morphologic features: issues relevant to Ancure and Talent endografts.

PURPOSE: The purpose of this study was to determine whether gender-related anatomic variables may reduce applicability of aortic endografting in women. METHODS: Data on all patients evaluated at our institution for endovascular repair of their abdominal aortic aneurysm were collected prospectively. Ancure (Endovascular Technologies (EVT)/Guidant Corporation, Menlo Park, Calif) and Talent (World Medical/Medtronic Corporation, Sunrise, Fla) endografts were used. Preoperative imaging included contrast-enhanced computed tomography and arteriography or magnetic resonance angiography. RESULTS: One hundred forty-one patients were evaluated (April 1998-December 1999), 19 women (13.5%) and 122 men (86.5%). Unsuitable anatomy resulted in rejection of 63.2% of the women versus only 33.6% of the men (P = .026). Maximum aneurysm diameter in women and men were similar (women, 56.94 +/- 8.23 mm; men, 59.29 +/- 13.22 mm; P = .5). The incidence of iliac artery tortuosity was similar across gender (women, 36.8%; men, 54.9%; P = .2). The narrowest diameter of the larger external iliac artery in women was significantly smaller (7.29 +/- 2.37 mm) than in men (8.62 +/- 2.07 mm; P = .02). The proximal neck length was significantly shorter in women (10.79 +/- 12.5 mm) than in men (20.47 +/- 19.5 mm; P = .02). The proximal neck width was significantly wider in women (30.5 +/- 2.4 mm) than in men (27.5 +/- 2.5 mm; P = .013). Proximal neck angulation (>60 degrees) was seen in a significantly higher proportion of women (21%) than men (3.3%; P = .012). Of the patients accepted for endografting, a significantly higher proportion of women required an iliofemoral conduit for access (women, 28.6%; men, 1.2%; P = .016). CONCLUSION: Gender-related differences in infrarenal aortic aneurysm morphologic features may preclude widespread applicability of aortic endografting in women, as seen by our experience with the Ancure and Talent devices. In addition to a significantly reduced iliac artery size, women are more likely to have a shorter, more dilated, more angulated proximal aortic neck.

Aged↗
PubMed2001

The role of magnetic resonance angiography for endoprosthetic design.

OBJECTIVES: Many patients with aortic aneurysms have renal insufficiency and may be at increased risk when conventional imaging modalities (contrast-enhanced computed tomography and arteriography) are used for aortic endograft design. Our objective was to determine if magnetic resonance angiography (MRA) could be used as the sole imaging modality for endoprosthetic design. METHODS: A total of 96 consecutive patients who underwent endovascular repair of thoracic (5) and abdominal (91) aortic aneurysms (April 1998-December 1999) were included in this study. Data were collected prospectively. Gadolinium-enhanced MRA was used preoperatively in place of conventional imaging if renal insufficiency or a history of severe contrast reaction was present. The control group underwent conventional imaging. Endografts used included Ancure, AneuRx, and Talent. RESULTS: Fourteen patients (14.6%) had their endografts designed solely with MRA. Intraoperative access failure; proximal and distal extensions (unplanned); conversion to open, aborted procedures; and endoleaks occurred with equal frequency in both the MRA-designed and control groups (16.7% vs 18.3%, respectively; P =.33). Despite baseline renal insufficiency, there was no significant rise in the creatinine level after endograft implantation in patients with an MRA design (preoperative level, 1.8; postoperative level, 1.9; P =.5). CONCLUSION: MRA may be successfully used as the sole modality for aortic endograft design. The use of MRA for this purpose is noninvasive and minimizes nephrotoxic risk.

Aortic Dissection↗
PubMed2001

Failure of endovascular abdominal aortic aneurysm graft limbs.

OBJECTIVE: Endovascular abdominal aortic aneurysm (AAA) grafts are subject to subsequent failure of endograft limbs. We sought to determine what device-related factors could be identified that might contribute to limb failure. METHODS: We reviewed the records of patients who had undergone endovascular AAA repair and femorofemoral bypass grafting at a single institution. RESULTS: Endovascular AAA repair was performed in 173 patients. There were 137 bifurcated endografts and 36 aortomonoiliac grafts combined with femorofemoral bypass grafts, yielding a total population of 310 aortic graft limbs and 36 femorofemoral grafts. Thirty-nine additional patients underwent femorofemoral bypass grafting for occlusive disease. The cumulative primary patency of all endografts performed for AAA was 92% at 21 months. Secondary patency was achieved for all failed endograft limbs. There were 24 aortic graft limb "failures" that required intervention: seven limbs underwent thrombosis requiring revision; kinked limbs requiring stenting either at the time of graft placement (17) or subsequently (7) were identified. Fully supported endograft limbs had better primary patency (97% at 18 months) than unsupported limbs (69% at 18 months, P <.001). The aortomonoiliac grafts with femorofemoral bypass grafts tended to have better patency (97% at 18 months) than bifurcated endografts (90% at 18 months), but this did not reach statistical significance (P =.28, not significant). Femorofemoral grafts performed for occlusive disease were found to have somewhat lower patency than those performed for AAA (83% vs 92% at 18 months of follow-up, P =.37, not significant). CONCLUSIONS: Fully supported AAA endografts provide superior endograft limb patency compared with unsupported designs. Consideration should be given to routine stenting of all unsupported endograft limbs. Aortomonoiliac grafts and bifurcated grafts provide similar results for endograft limb patency. Femorofemoral bypass grafts performed in conjunction with aortomonoiliac grafts for AAA disease provide excellent short-term patency.

Adult↗
PubMed2001

Impact of exclusion criteria on patient selection for endovascular abdominal aortic aneurysm repair.

PURPOSE: Wide-ranging predictions have been made about the usefulness of endovascular repair for patients with abdominal aortic aneurysms (AAAs). The availability of US Food and Drug Administration-approved devices has removed the restrictions on patient selection, which had been controlled by device trials. This study examined the applicability of endovascular AAA repair and identified the anatomic barriers to successful endovascular AAA repair that should guide future device development. METHODS: All patients who came to our institution for infrarenal AAA repair between April 1998 and June 2000 were offered evaluation for endovascular repair. Thin-cut spiral computed tomography scans and arteriograms were obtained on all patients, and their anatomic characteristics were prospectively entered into a database. A wide selection of available devices allowed the treatment of diverse AAA anatomic features. RESULTS: A total of 307 patients were examined (264 men, 43 women). Of these, 204 patients (66%; 185 men, 19 women) underwent endovascular repair, and 103 patients (34%, 79 men, 24 women) were rejected. Reasons for exclusion included short aneurysm neck (56, 54%), inadequate access because of small iliac arteries (48, 47%), wide aneurysm neck (41, 40%), presence of bilateral common iliac aneurysms extending to the hypogastric artery (22, 21%), excessive neck angulation (14, 14%), extensive mural thrombus in the aneurysm neck (10, 10%), extreme tortuosity of the iliac arteries (10, 10%), accessory renal arteries originating from the AAA (6, 6%), malignancy discovered during the examination (5, 5%), and death during the examination interval (2, 2%). Rejected patients had an average of 1.9 exclusion criteria (range, 1 to 4). A disproportionate number of women were excluded because of anatomic findings (P = .0009). Although 80% of patients who were at low risk for surgery qualified for endovascular repair, only 49% of our patients who were at high risk for surgery were acceptable candidates (P < .001). Of the 103 patients who were excluded, 34 (33%) underwent open surgical repair, and the remaining 69 (67%) were deemed to be unfit for open surgery. Three patients (1.4%) failed endograft placement because of inadequate vascular access. CONCLUSION: Most infrarenal AAAs (66%) can be treated with endovascular devices currently available commercially or through US Food and Drug Administration-approved clinical trials. However, patients who are at high risk for surgery and might benefit most from endovascular repair are less likely to qualify for the procedure (49%). Men (70%) are more likely than women (40%) to meet the anatomic criteria for endografting. Difficulties with vascular access and attachment site geometry predominate as reasons for exclusion. Our findings suggest that smaller profile devices, which can negotiate small and tortuous iliac arteries, are needed. Proximal and distal attachment site problems require devices that can accommodate wide and angulated attachment necks and achieve short seal zones.

Aged↗
PubMed2001

Therapeutic thrombin injection of pseudoaneurysms: a multicenter experience.

The standard non-invasive treatment of pseudoaneurysms has been ultrasound-guided compression (UGC). Problems with UGC include pain at the site of compression, long compression times and incomplete closure. Each of these difficulties is exacerbated with large pseudoaneurysms. Recently, ultrasound-guided injection of pseudoaneurysms with thrombin has gained popularity. The goal of this study was to report a multicenter registry using this technique and in so doing detail the clinical utility and safety of this emerging procedure. The medical records of all patients diagnosed with pseudoaneurysm in the vascular laboratory who underwent thrombin injection over the past year were reviewed for patient characteristics and clinical outcome. There were 91 patients (55 male) with a mean age of 69 years. Three patients also had an arteriovenous fistula. The majority of patients were receiving one or more antiplatelet agents and/or anticoagulants. All patients underwent pseudoaneurysm injection with bovine thrombin. The mean aneurysm diameter was 3.3 cm, with a range of 1.5-6.3 cm. Successful thrombosis of the pseudoaneurysm was achieved in 89/91 (98%) of cases. Anticoagulation with heparin was used in one of the unsuccessful cases. In two cases, UGC was used to close a small active region that did not completely thrombose after thrombin injection. There were two patients who had recurrence of pseudoaneurysm the day after successful injection and thrombosis of the pseudoaneurysm. There were no local complications after injection; however, one patient suffered a pulmonary embolus that was thought to be unrelated to the procedure. In conclusion, thrombin injection for the treatment of pseudoaneurysms is safe and effective, even in patients receiving anticoagulation. This procedure should be considered as the initial therapeutic approach for peripheral pseudoaneurysms.

Adult↗
PubMed2001

Duplex criteria for determination of 50% or greater carotid stenosis.

Recently the North American Symptomatic Carotid Endarterectomy Trial investigators reported a benefit of carotid endarterectomy compared with medical therapy for symptomatic patients with 50% or greater carotid stenosis. This has necessitated the development of screening parameters for diagnosis of 50% or greater carotid stenosis on the basis of the reference standards used in the study by the North American Symptomatic Carotid Endarterectomy Trial. The duplex scans and arteriograms of 110 patients (210 carotid arteries) were reviewed by blinded readers. Duplex measurements of peak systolic velocity and end diastolic velocity were recorded, and the ratio of these velocities in the internal and common carotid arteries was calculated. The criteria determined for detection of 50% or greater stenosis were as follows: peak systolic velocity of the internal carotid artery greater than 170 cm/s (sensitivity, 92%; specificity, 90%; positive predictive value, 92%; negative predictive value, 90%; and accuracy, 91 %); end diastolic velocity of the internal carotid artery greater than 60 cm/s (sensitivity, 92%; specificity, 86%; positive predictive value, 95%; negative predictive value, 79%; and accuracy, 91 %); ratio of peak systolic velocity of the internal carotid artery to peak systolic velocity of the common carotid artery greater than 2 (sensitivity, 93%; specificity, 75%; positive predictive value, 83%; negative predictive value, 89%; and accuracy, 85%); and ratio of end diastolic velocity of the internal carotid artery to end diastolic velocity of the common carotid artery greater than 2.4 (sensitivity, 96%; specificity, 79%; positive predictive value, 88%; negative predictive value, 92%; and accuracy, 89%). It is concluded that 50% or greater carotid artery stenosis can be reliably determined by duplex criteria. The use of receiver operating characteristic curves allows the individualization of duplex criteria to the clinical situation.

Blood Flow Velocity↗
PubMed2000

Limb kinking in supported and unsupported abdominal aortic stent-grafts.

PURPOSE: The occurrence of kinking of stent-graft limbs depends on the patient's anatomy and the device used. The purpose of this investigation was to determine the rates of limb kinking in supported and unsupported aortic stent-grafts. MATERIALS AND METHODS: The authors performed a retrospective review of patients undergoing placement of either a Guidant Ancure/EGS or Medtronic Talent aortic stent-graft for the treatment of abdominal aortic aneurysm as part of separate phase II and phase III clinical trials. The records of 91 consecutive patients with 149 limbs were reviewed. The type and configuration of each device and any procedure performed specifically relating to limb patency was recorded. An analysis was then performed comparing the rates of kinking in supported and unsupported groups. A review of the literature was also performed. RESULTS: Overall, there was kinking in 18 of 149 limbs (12%). In the supported stent-graft group, 48 bifurcated and 26 aortomonoiliac grafts were placed, with a total of 122 limbs at risk. Six limbs (5%) in five patients required intervention as a result of limb kinking. Stents were placed intraoperatively in two limbs (2%) and postoperatively in four limbs (3%) for thrombosis or severe stenosis. In the unsupported group, 12 bifurcated and three aortomonoiliac grafts were placed, with a total of 27 limbs at risk. Twelve limbs (44%) in eight patients required some type of intervention as a result of limb kinking. Stents were placed intraoperatively in seven limbs (26%) and postoperatively in five limbs (19%) for thrombosis or severe stenosis. Rates of limb kinking were significantly different between the supported and unsupported groups (P < .0001). CONCLUSIONS: The use of supported versus unsupported stent-grafts impacts the occurrence of limb kinking. A direct comparison of the groups suggests that an unsupported stent-graft will be more than 15 times more likely than a supported system to require intervention because of kinking.

Angiography↗
PubMed2000

Cellular repopulation of human vein allograft bypass grafts.

PURPOSE: Vein allografts are an alternative conduit for patients lacking available autogenous vein. The ability to develop a neoendothelium is a potential advantage of allografts over other nonautogenous grafts, because endothelial cells have been shown to play numerous essential roles in vessel survival. However, repopulation by endothelial cells has not previously been demonstrated or characterized in human subjects. METHODS: In our prospective trial, 40 patients (20 men, 20 women) underwent cryo- preserved saphenous vein bypass grafting procedures for limb salvage. Several patients underwent multiple grafting procedures. All grafts were sampled at implantation. During the 31 month follow-up interval, 22 allografts were explanted at the time of revision or subsequent surgical procedure. All grafts (22 of 22) demonstrated intact endothelium at implantation and explantation. Seventeen explantation biopsy samples (seven from men, 10 from women) from 16 patients (seven men, nine women) were adequate for further histologic and immunofluorescent analysis. Explants were stained with hematoxylin-eosin and immunohistochemical markers to quantitate rejection and also underwent fluorescence in-situ hybridization, with probes for X and Y chromosomes and counterstain for nuclear envelope. Cells were counted as XX, XY, XO, YO, or unstained. The endothelium and vessel walls were analyzed for origin of cells based on sex-mismatched transplants, with sex-matched transplants serving as controls. RESULTS: Evidence of cellular damage was noted in all explanted allografts, and moderate or severe rejection (lymphocyte infiltrate, +CD3, +CD8, +CR3, cytotoxic granules) was noted in six explanted allografts (29%). All allografts demonstrated intact endothelium (complete or partial), at the time of both implantation and explantation. Sex-matched (male to male) control explants showed only male cells, as expected. Male donor-female recipient transplants showed complete repopulation by recipient (female) cells in nine of 10 cases (90%), whereas one case (10%) demonstrated partial repopulation (a mosaic of male and female cells). One patient's slides were unreadable. Findings in cells of the allograft wall were identical to those of the endothelium (nine recipient-only cells and one mosaic). Complete absence of donor cells was noted as early as 1 week after implantation, but mosaicism was demonstrated in one patient 3 months after grafting. No relationship could be demonstrated between repopulation and time (P >.05), quantity of rejection (P >.05), or donor age (P >.05). CONCLUSION: Both the endothelial lining and vessel wall of venous allografts repopulate with cells of recipient origin, resulting in either a completely novel cellular constituency or a mosaic of host and donor cells. The loss of donor cells may be mediated by apoptosis or rejection, and the rate of migration of repopulating host cells is, at this point, unclear. Although the development of a completely endothelial-lined conduit offers a potential advantage over other alternative conduits, the functional status of the neoendothelium and repopulated vessel wall and their role in maintenance of allograft patency require further investigation.

Cell Division↗
PubMed2000

Relationship between preoperative patency of the inferior mesenteric artery and subsequent occurrence of type II endoleak in patients undergoing endovascular repair of abdominal aortic aneurysms.

OBJECTIVES: The purpose of this study was (1) to find out whether preoperative inferior mesenteric artery (IMA) patency (on radiographic imaging) predicts IMA-related endoleaks after endovascular repair of infrarenal abdominal aortic aneurysms, (2) to determine feasibility of measuring aneurysm sac pressures in patients with endoleaks, and (3) to report early evidence of effective endovascular obliteration of IMA endoleaks. METHODS: We studied 76 consecutive cases of infrarenal aortic aneurysms that were repaired with an endovascular approach (March 1998-April 1999). RESULTS: There were 13 (17%) endoleaks persistent 30 days after the procedure. Eleven (85%) of these 13 were IMA-related endoleaks, which were documented with selective superior mesenteric artery angiography. The preoperative finding (on computed tomographic scan) of a patent IMA does not always predict an IMA-related endoleak, but results in a statistically and clinically significant higher ratio of patients with IMA-related endoleaks in the immediate postoperative period (24% versus 3%, P <.035). In eight of the 11 patients with persistent IMA-related endoleaks, measurement of intra-aneurysm sac pressures was possible, and six of these patients had systemic pressures within the excluded aneurysm sac. Nine (82%) of 11 IMA-related endoleaks were successfully obliterated by means of selective IMA embolization. CONCLUSIONS: Many endoleaks are caused by a patent IMA, and this can result in persistence of systemic pressure within the aneurysm sac. The preoperative finding (on computed tomographic scan) of a patent IMA is a predictor of increased rates of IMA endoleaks, and IMA endoleaks can be successfully obliterated through endovascular procedures, after endovascular abdominal aortic aneurysm repair.

Aortic Aneurysm, Abdominal↗
PubMed2000

Safety of coil embolization of the internal iliac artery in endovascular grafting of abdominal aortic aneurysms.

PURPOSE: During endovascular grafting of an abdominal aortic aneurysm (AAA), iliac limb extension to the external iliac artery may be indicated when the common iliac artery is ectatic or aneurysmal. Preliminary or concomitant coil embolization of the internal iliac artery (IIA) is thus necessary to prevent potential reflux and endoleak. We sought to determine the safety of hypogastric flow interruption in this setting. METHODS: We retrospectively reviewed 156 patients who underwent stent-graft AAA repair at two institutions between February 1, 1998, and January 31, 1999. Coil embolization of one or both IIAs was undertaken when the diameter of the common iliac artery was more than 20 mm to enable limb endograft extension to the external iliac artery. Bilateral procedures were staged. RESULTS: Thirty-nine (25%) of 156 patients were selected for coil embolization of one (n = 28) or both (n = 11) IIAs. The interventions were performed before (n = 31) or during (n = 8) the stent-graft procedure. Complications included groin hematomas in 3 patients, iliac artery dissection in 1, failure to catheterize the IIA in 2, and transient rise in the serum creatinine level in 3. One patient had erectile dysfunction, and five patients (13%) had buttock claudication after unilateral occlusion. Serious ischemic complications were not observed. CONCLUSION: Coil embolization of one or both IIAs appears to be safe in the setting of endovascular grafting of AAA. Buttock claudication is a relatively significant problem and may limit applicability of this strategy to patients who are unfit for standard open repair.

Aged↗