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Biomedical subjects

Gregory L Moneta

Publications and source records attributed to Gregory L Moneta.

32 records · Page 2Linked to original sources
PubMed2002

Repeat axillofemoral grafting as treatment for axillofemoral graft occlusion.

BACKGROUND: Patency of failed axillofemoral (ax-fem) grafts following thrombectomy is so poor, aortofemoral grafts are recommended as treatment for ax-fem graft thrombosis. In patients who are not candidates for aortic grafting, repeat ax-fem grafting is an alternative to thrombectomy. This report compares our experience treating ax-fem graft thrombosis with replacement or revision vs thrombectomy. METHODS: Patients treated with ax-fem grafts from October 1985 to April 2001 were identified, and those who underwent reoperation for thrombosis were reviewed. Limb salvage and patency of revision procedures (thrombectomy vs repeat ax-fem grafting) were determined using Kaplan-Meier curves. RESULTS: Three hundred thirty-five patients underwent ax-fem grafting, and 39 (11.6%) of the 335 required reoperation for graft failure. Twenty-five of these 39 patients had 51 operations for graft thrombosis: 42 graft replacements and/or anastomotic revision(s), and 9 thrombectomies. At 18 months, mean +/- SD patency following thrombectomy was 11% +/- 10%, while that for graft replacement or anastomotic revision was 54% +/- 8% (P<.001). Limb salvage at 18 months following revision for thrombosis was 88% +/- 5%. CONCLUSIONS: The large majority of ax-fem grafts do not require reoperation. For failure due to thrombosis, repeat ax-fem grafting provides excellent limb salvage. Axillofemoral graft replacement and/or anastomotic revision has superior patency to thrombectomy.

Adult↗
PubMed2002

Vascular surgery for peripheral arterial disease.

The North American Symptomatic Carotid Endarterectomy Trial (NASCET) confirmed that carotid endarterectomy (CEA) can significantly cut the risk of stroke in patients with moderate and severe blockage. The standard today is that patients who have internal carotid artery stenosis > 70% with associated symptoms and who are appropriate surgical candidates should be offered CEA. Aneurysmal disease, a growing public health concern, poses the threat of death from rupture, and lower extremity arterial occlusive disease poses a significant risk of critical leg ischemia and limb loss. Both conditions involve surgical options. In treating their patients, primary care physicians should become familiar with the benefits and risks of vascular surgery to manage the various aspects of peripheral arterial disease.

Angiography↗
PubMed2002

Homocysteine and arterial disease. Experimental mechanisms.

Hyperhomocysteinemia (hH(e)) in the general population is associated with incidence and progression of arterial occlusive disease, although the underlying mechanisms are not well defined. Current research supports a role for homocysteine (H(e))-mediated endothelial damage and endothelial dysfunction. This mechanism appears to be a key factor in subsequent impaired endothelial-dependent vasoreactivity and decreased endothelium thromboresistance. These consequences may predispose hyperhomocysteinemic vessels to the development of increased atherogenesis. Additional mechanisms of H(e)-mediated vascular pathology, including protein homocysteinylation and vascular smooth muscle cell proliferation may also play a role. Continued investigation into the mechanisms contributing to H(e) toxicity will provide further insight into the processes by which hH(e) may increase atherosclerosis.

Animals↗
PubMed2002

Percutaneous bioprosthetic venous valve: a long-term study in sheep.

A long-term evaluation of a new percutaneously placed bioprosthetic, bicuspid venous valve (BVV) consisting of a square stent and small intestinal submucosa (SIS) covering was performed in 12 sheep. Of 26 BVVs placed into the jugular veins, 25 exhibited good valve function on immediate venography and 22 on venograms obtained before the sheep were killed. Gross and histologic examination results demonstrated incorporation of remodeled and endothelialized SIS BVVs into the vein wall. Slight to moderate leaflet thickening was found mostly at their bases. Percutaneously placed SIS BVV is a promising one-way, competent valve that resists venous back-pressure while allowing forward flow.

Animals↗
PubMed2002

Choice of autogenous conduit for lower extremity vein graft revisions.

BACKGROUND: Surgical revision to repair stenosis is necessary in about 20% of lower extremity vein grafts (LEVGs). Alternate conduit, especially arm vein, is often necessary to achieve a policy of all-autogenous revisions. Although basilic vein harvest necessitates deep exposure in proximity to major nerves, it typically uses a large vein unaffected by prior intravenous lines and as such appears ideally suited for revisions in which a segmental interposition conduit is needed for revision within the graft or for extension to a more proximal inflow or distal outflow site. In this report, we describe our experience with the use of the basilic vein for LEVG revisions compared with other sources of autogenous conduit. METHODS: All patients who underwent LEVG were placed in a duplex scan surveillance program. LEVGs that developed a focal area of increased velocity or uniformly low velocities throughout the graft with appropriate lesions confirmed with angiography were candidates for revision. All patients who underwent graft revision with basilic vein segments from January 1, 1990, to September 1, 2001, were identified, and their courses were reviewed for subsequent adverse events (further revision or occlusion) and complications of harvest. These revisions were compared with revisions in which cephalic and saphenous vein were used. RESULTS: One hundred thirty basilic veins were used to revise 122 LEVGs. The mean follow-up period after revision was 28 +/- 27 months. Ninety-three grafts (71%) remained patent with no further revision, and 37 grafts (29%) either needed additional revisions (22 grafts) or were occluded (15 grafts). Only four of these adverse events (11%) were directly attributed to the basilic vein segment. Ten of 43 grafts revised with cephalic vein (23%) were either revised or occluded, of which three were related to the cephalic vein segment (P = not significant, compared with basilic vein). Twenty-four of 81 grafts revised with saphenous vein (30%) were either revised or occluded, of which 11 were attributed to the saphenous vein segment (P <.01, compared with basilic vein). Two patients (1.5%) had complications from basilic vein harvest (one hematoma, one arterial injury). No neurologic injuries resulted from basilic vein harvest. CONCLUSION: The basilic vein is a reliable and durable conduit when used to segmentally revise LEVGs. Stenoses rarely occur within interposed basilic vein segments, and excellent freedom from subsequent revision or occlusion is possible. We conclude the basilic vein can be safely harvested with minimal complications and is ideally suited for use as a short segment interposition graft for LEVG revision.

Arm↗
PubMed2002

Relationship of hemodialysis access to finger gangrene in patients with end-stage renal disease.

OBJECTIVE: We report a comprehensive review of our patients on hemodialysis with end-stage renal disease (ESRD) with finger gangrene to determine etiology, natural history, and prognosis of this condition. METHODS: Patients with ESRD with finger gangrene were identified from our computerized vascular registry. Presence of an ipsilateral arteriovenous fistula was determined, and patients were compared with a group of patients with ESRD without finger gangrene. Management consisted of arteriography, selective arteriovenous fistula management, and finger amputation. A multivariate analysis to determine risk factors associated with finger gangrene was performed. Repeat finger amputation and survival rates were determined with life-table analysis. RESULTS: Twenty-three patients (mean age at start of dialysis, 53 years) with finger gangrene were identified, with 48% (n = 11) having a functional ipsilateral arteriovenous fistula. Arteriography was consistent with diffuse atherosclerosis involving the radial, ulnar, palmar, and digital arteries precluding attempts at distal arterial bypass. Repeat finger amputations were necessitated in 52% of patients (n = 12), and bilateral finger gangrene developed in 61% of patients (n = 14). Starting dialysis at age less than 55 years (P =.0004), diabetes (P =.001), coronary artery disease (P =.0212), and lower extremity arterial occlusive disease (P <.0001) were significantly associated with finger gangrene. CONCLUSION: The young diabetic patient with diffuse vascular disease and ESRD is at high risk for the development of finger gangrene on chronic hemodialysis. Finger gangrene is the result of distal atherosclerosis and is not primarily related to dialysis access.

Adult↗
PubMed2002

Relationship between site of initial symptoms and subsequent progression of disease in a prospective study of atherosclerosis progression in patients receiving long-term treatment for symptomatic peripheral arterial disease.

PURPOSE: There have been few studies of the natural history of peripheral arterial disease (PAD), and none have used serial noninvasive laboratory examinations for the objective quantification of disease progression. The relationship between the site of initial symptoms of PAD (lower-extremity disease [LED] vs cerebrovascular disease [CVD]) and the site of subsequent symptomatic progression (LED vs CVD vs coronary heart disease [CHD]) has not been examined. METHODS: This is a long-term, blinded prospective clinical research study of the relationship of PAD progression to multiple clinical, laboratory, and noninvasive vascular laboratory parameters. Patients with symptomatic LED, CVD, or both underwent comprehensive risk-factor assessment and were seen every 6 months for follow-up examinations. In addition to history and physical examination, all subjects underwent serial noninvasive lower-extremity and carotid artery testing. The relationship between the initial symptomatic site(s) and subsequent progression was examined by means of multivariate proportional hazards analysis, which was adjusted for age, diabetes mellitus, hypertension, smoking, cholesterol, homocysteine level, lowest initial ankle/brachial index (ABI), worst carotid stenosis, ABI progression, and carotid stenosis progression, because each of these factors was significantly associated with one or more aspects of progression. RESULTS: There were 397 study subjects (mean age, 66 years; 38% women) with a mean follow-up period of 48.5 months. LED was initially present in 88% of subjects and CVD in 37% of subjects (both were present in 25% of subjects). There were 78 deaths, 47 (60%) of which were caused by cardiovascular disease (18% mortality rate after 5 years by means of life table). Progression of disease as documented by means of vascular laboratory findings occurred in 90% of subjects by means of life table after 5 years (ABI progression, 31%; carotid stenosis progression, 40%). Symptomatic clinical progression of disease occurred in 52% of subjects by means of life table after 5 years (LED progression, 22%; CVD progression, 23%; CHD progression, 31%). By means of multivariate analysis, no significant relationship was found between the site of initial symptoms of PAD and the site(s) of subsequent symptomatic clinical progression (LED vs CVD vs CHD; P = not significant for all hazard ratios). CONCLUSION: Patients with symptomatic PAD experience symptoms of ongoing LED, CVD, and CHD with a frequency that is not influenced by the site(s) of their original symptoms. The hypothesis that lesions and resulting symptoms of systemic atherosclerosis occur at various anatomic sites as a matter of random chance should be tested with other studies.

Aged↗
PubMed2002

Long-term outcome of revised lower-extremity bypass grafts.

PURPOSE: Reversed lower-extremity vein grafts (LEVGs) frequently require operative revisions to maintain patency. Identifying grafts that are at risk, however, requires an intensive duplex scanning-based surveillance program. Excellent 5-year graft patency and limb-salvage rates have previously been reported in patients undergoing graft revisions, but results beyond 5 years are essentially unknown, a factor that is of importance in an increasingly aging population. This study was performed to determine the results of surgical revisions of LEVGs after a follow-up as long as 10 years. METHODS: All patients undergoing placement of a LEVG were observed in a program of duplex scanning-based surveillance as long as the patient remained a candidate for graft revision. Grafts were considered for revision on the basis of the presence of focal areas of increased velocity, a prestenotic to intrastenotic velocity ratio more than 3.0, or uniformly low velocities throughout the graft. All lesions were confirmed with preoperative arteriography before revision. Assisted primary patency, limb-salvage, and survival rates were determined by means of Kaplan-Meier analysis in all patients who underwent LEVG revision from January 1990 to December 2000. RESULTS: A total of 1498 LEVG procedures were performed during the study period. A total of 330 surgical graft revisions were performed on 259 extremities in 245 patients. The median follow-up period was 38 months. The assisted primary patency rate of all grafts, the limb-salvage rate for patients undergoing surgery for limb-salvage indications, and the survival rate of all patients were 87.4%, 88.7%, and 72.4%, respectively, 5 years after the original bypass grafting procedure, 85.7%, 83.4%, and 67.8%, respectively, 7 years after the original bypass grafting procedure, and 80.4%, 75.4%, and 53.4%, respectively, 10 years after the original bypass grafting procedure. A total of 180 revisions (55%) were performed during the first year, 110 (33%) between the first year and the fifth year, and 40 revisions (12%) were performed on grafts older than 5 years. LEVGs revised within the first year after bypass grafting had lesions within the graft in 78%, in the native arterial inflow in 10%, and in the native arterial outflow in 12%. This differed significantly from the location of lesions in revisions performed between 1 and 5 years and after 5 years (graft, 63% and 62%; inflow, 20% and 19%; outflow, 17% and 19%; P >.05, Chi-square). CONCLUSION: Excellent assisted primary patency and limb-salvage rates can be achieved for as long as 10 years in LEVGs that require revision, with only a 7% drop in overall patency and limb-salvage rates between the fifth and 10th years. Although most revisions were required within the first year, 34% were performed between the first year and the fifth year, and 11% after 5 years. These data support the growing body of evidence that favors an aggressive regimen of duplex scanning surveillance of LEVGs for the life of the graft. Revised grafts have excellent patency through 10 years.

Aged↗
PubMed2002

Neointimal hyperplasia in balloon-injured rat carotid arteries: the influence of hyperhomocysteinemia.

PURPOSE: Hyperhomocyst(e)inemia (hH[e]) is a risk factor for atherosclerosis. Neointimal hyperplasia (NH) after vessel injury can contribute to atherosclerosis. In this study, we investigated the effects of hH(e) on NH formation after arterial balloon injury in rats. METHODS: Lewis rats that were given a hH(e)-inducing (high methionine, low folate) or normal diet for 150 days underwent common carotid artery (CCA) balloon injury. Two and 4 weeks after injury, CCAs were formalin perfusion-fixed, sectioned, and stained for elastin. Neointimal index (NI, percent lumen occlusion) and neointima (N) and media (M) area were measured by using computer-interfaced microscopy. RESULTS: Plasma homocyst(e)ine (H[e]) levels were elevated in rats given the study diet compared with rats given the normal diet at days 40 and 90 (69 +/- 8 and 73 +/- 9 micromol/L vs 4 +/- 0.4 and 4 +/- 0.6 micromol/L, P <.001). After balloon injury, the CCA NI and N/M ratio, but not the M area, were increased by hH(e) compared with normal plasma H(e) (2 weeks [n = 6,7]: NI = 7.3 +/- 1.7 vs 2.9 +/- 0.7, P =.002, and N/M = 0.31 +/- 0.08 vs 0.08 +/- 0.02, P <.001; 4 weeks [n = 4,7]: NI = 13.1 +/- 2.2 vs 6.3 +/- 1.3, P =.002, and N/M = 0.36 +/- 0.08 vs 0.17 +/- 0.03, P <.001). CONCLUSION: hH(e) accelerates NH in a rat CCA balloon-injury model. The effect of hH(e) on NH may contribute to increased atherosclerosis in humans with hH(e).

Animals↗
PubMedDate not supplied

Carotid surgery following previous carotid endarterectomy is safe and effective.

With the perceived high risk of repeat carotid surgery, carotid angioplasty and stenting have been advocated recently as the preferred treatment of recurrent carotid disease following carotid endarterectomy. An experience with the operative treatment of recurrent carotid disease to document the risks and benefits of this procedure is presented. A review of a prospectively acquired vascular registry over a 10-year period (Jan. 1990-Jan. 2000) was undertaken to identify patients undergoing repeat carotid surgery following previous carotid endarterectomy. All patients were treated with repeat carotid endarterectomy, carotid interposition graft, or subclavian-carotid bypass. The perioperative stroke and death rate, operative complications, life-table freedom from stroke, and rates of recurrent stenosis were documented. During the study period 56 patients underwent repeat carotid surgery, comprising 6% of all carotid operations during this period. The indication for operation was symptomatic disease recurrence in 41 cases (73%) and asymptomatic recurrent stenosis >/=80% in 15 cases (27%). The average interval from the prior carotid endarterectomy to the repeat operation was 78 months (range 3 weeks-297 months). The operations performed included repeat carotid endarterectomy with patch angioplasty in 31 cases (55%), interposition grafts in 19 cases (34%), and subclavian-carotid bypass in 6 cases (11%). There were three perioperative strokes with one resulting in death for a perioperative stroke and death rate of 5.4%. One minor transient cranial nerve (CN IX) injury occurred. Mean follow-up was 29 months (range, 1-116 months). Life-table freedom from stroke was 95% at 1 year and 90% at 5 years. Recurrent stenosis (>/=80%) developed in three patients (5.4%) during follow-up, including one internal carotid artery occlusion. Two patients (3.6%) underwent repeat surgery. Repeat surgery for recurrent cerebrovascular disease following carotid endarterectomy is safe and provides durable freedom from stroke. Most patients are candidates for repeat endarterectomy with patching, but interposition grafting is often required. These results strongly support the continued role of repeat carotid surgery in the treatment of recurrent carotid disease.

Aged↗
PubMedDate not supplied

Outcomes after redo procedures for failed mesenteric revascularization.

This report examines results of mesenteric revascularization following a failed splanchnic revascularization. Patients undergoing repeat mesenteric revascularization from January 1985 to July 2002 were identified from a prospectively maintained registry. Data recorded included procedures performed, perioperative mortality, complications, and operative indications. Patients who had embolic events were excluded. Eighty-six patients underwent 105 mesenteric interventions in this time period; 22 patients underwent 33 repeat mesenteric revascularization procedures. There were 25 single-vessel bypasses, 3 multivessel reconstructions, 3 angioplasty procedures (1 open, 2 percutaneous), and 2 graft thrombectomies. Complications occurred in 33.3%. Perioperative mortality was 6.1%, all in patients with acute mesenteric ischemia. One- and 4-year primary patency for repeat mesenteric revascularization was 73.5% and 62.2%, respectively, and survival for repeat mesenteric revascularization was 85.9% and 75.5%, respectively. Patients surgically treated for mesenteric ischemia can require additional interventions. Repeat revascularization effectively prolongs survival when an earlier intervention fails.

Adult↗
PubMedDate not supplied

Design and rationale of the PREVENT III clinical trial: edifoligide for the prevention of infrainguinal vein graft failure.

Surgical bypass of peripheral arterial occlusive disease with autologous vein grafts provides an effective means of restoring blood flow to the lower extremity, and has been a standard therapy for patients with disabling claudication or critical limb ischemia (CLI). However, failure rates may run as high as 50% within 5 years. These graft failures occur as a result of neointimal hyperplasia, a ubiquitous biologic response of blood vessel walls to injury, which is characterized by the migration and proliferation of smooth muscle cells (SMC). The E2F family of transcription factors regulates the expression of genes controlling SMC proliferation. Edifoligide (E2F Decoy) is a novel therapy that inhibits E2F function, thus attenuating neointimal hyperplasia. Its use in conjunction with a patented drug delivery pressurization chamber is under investigation. Using this system, edifoligide is administered to vein grafts in a single, ex vivo treatment following vein harvest and before implantation, resulting in minimal systemic drug exposure and excellent patient compliance. This Phase 3, randomized, double-blind, multicenter clinical trial is designed to evaluate the safety and efficacy of edifoligide in a population of approximately 1400 patients with CLI undergoing infrainguinal bypass for peripheral arterial disease (PAD). The primary outcome measure will be the time to occurrence of non-technical graft failure resulting in either graft revision or major amputation at 12 months after enrollment. A governing Clinical Events Classification committee (CEC) will adjudicate each graft failure to determine its etiology. The PREVENT III trial is the largest multicenter trial ever performed in patients receiving autologous vein bypass grafts for CLI. This landmark study will determine if edifoligide is safe and effective at preventing vein graft failure in patients undergoing lower extremity bypass, but it also provides a unique opportunity to observe current treatment practices in vascular surgery.

Arterial Occlusive Diseases↗