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Metamorphosis of vascular surgeons to endovascular specialists: must vascular surgery have an independent board and can we get there? [Editorial]
Veith, Frank J
PMID: 15943500
ISSN: 1526-6028
CID: 79513
Influence of type II endoleak volume on aneurysm wall pressure and distribution in an experimental model
Timaran, Carlos H; Ohki, Takao; Veith, Frank J; Lipsitz, Evan C; Gargiulo, Nicholas J 3rd; Rhee, Soo J; Malas, Mahmood B; Suggs, William D; Pacanowski, John P
OBJECTIVE(S): We have previously shown that type II endoleak size is a predictor of aneurysm growth after aortic endografting. To better understand this observation, we investigated the influence of endoleak size on pressure transmitted to the aneurysm wall and its distribution within the aneurysm sac. METHODS: In an ex vivo model, an artificial aneurysm sac was incorporated within a mock circulation comprised of rubber tubing and a pulsatile pump. Three strain-gauge pressure transducers were placed in the aneurysm wall at different locations, including the site of maximum aneurysm diameter. The aneurysm was filled with either human aneurysm thrombus or dough that mimicked thrombus and simulated type II endoleaks of varying volumes (1 to 10 mL) were created. Aneurysm wall pressure (AWP) measurements were recorded at mean arterial pressures (MAPs) of 60, 80, and 100 mm Hg. Correlation coefficients ( r ) and analysis of variance were used to assess the relationship between endoleak volume and AWP. RESULTS: Increasing endoleak volume '3 cm 3 resulted in proportionally increased AWP at all levels of MAP and at all sites, with highest pressures recorded at the site of the maximum aneurysm diameter (r = 0.83 when MAP = 100 mm Hg; r = 0.85 when MAP = 80 mm Hg; r = 0.88 when MAP = 60 mm Hg; P < .001). AWP plateaued when the endoleak volume was >3 cm 3 . Pressure distribution within the sac was not uniform. Although the difference was within +/-10%, statistically significant higher AWPs were observed at the site of maximum aneurysm diameter (P <.001). AWP also correlated with MAP. CONCLUSIONS: Increasing type II endoleak volume results in proportionally higher AWP, which is greatest at the site of maximum aneurysm diameter. This study confirms the clinical observation that type II endoleak volume and MAP may be important predictors of aneurysm expansion. CLINICAL RELEVANCE: Our experimental model of a type II endoleak revealed that endoleak size is a significant factor that influences the magnitude of pressure transmission into the aneurysm wall. Increasing volume of the endoleak nidus was associated with proportionally higher aneurysm sac pressures. This mechanism may, in fact, account for the increased risk of aneurysm expansion observed in our clinical experience, thereby suggesting the need for more aggressive surveillance and possibly earlier intervention for patients with larger endoleaks
PMID: 15874931
ISSN: 0741-5214
CID: 79514
Endovascular aortic aneurysm repair with the Zenith endograft in patients with ectatic iliac arteries
Timaran, Carlos H; Lipsitz, Evan C; Veith, Frank J; Chuter, Timothy; Greenberg, Roy K; Ohki, Takao; Nolte, Lorraine A; Snyder, Scott A
Endovascular aortic aneurysm repair (EVAR) in patients with ectatic iliac arteries is feasible; however, most studies have reported experience from single institutions where distal flare techniques with endograft components were used on an 'off-label basis.' The Zenith endovascular graft allows adequate seal in ectatic common iliac arteries (CIAs) with diameters up to 20 mm. To determine whether large or ectatic CIAs are a risk factor for early and late endograft failure, we analyzed data from the Zenith U.S. multicenter trial. Among 352 patients receiving the endograft in the Zenith u.s. clinical study, 156 patients (44%) had at least one ectatic iliac artery (maximum diameter between 14 and 20 mm), whereas 22 (6.3%) had bilateral CIAs of normal diameter (< 14 mm). Variables analyzed included those defined by the reporting standards for EVAR (SVS/AAVS) as well as iliac-related outcome and indications for secondary iliac interventions. Univariate (Kaplan-Meier [KM] receiver operating characteristics curve, and Cox regression analyses were used to determine the association between CIA diameter and iliac-related complications. The median follow-up period was 24 months. Technical success was similar (>99%) for patients with ectatic and normal CIAs. Only one late type I distal endoleak was reported and was attributed to failure of distal iliac seal in a patient with ectatic CIAs. Freedom from iliac-related secondary intervention (IRSI) was not significantly different between the groups (KM, log-rank test, p = 0.98) with rates at 1, 12, and 24 months of 98%, 97%, and 95% for patients with ectatic CIAs, and 100%, 95%, and 95% for patients with normal iliac arteries, respectively. Moreover, Cox regression analysis revealed that the maximum CIA diameter was not a significant predictor of freedom from IRSI (hazard ratio, 0.98; 95% confidence interval, 0.7-1.4; p = 0.98). In patients with large CIAs, indications for IRSI included distal type I endoleak (1, 0.6%), type III endoleak (1, 0.6%), graft limb occlusion (4, 2.6%), and device stenosis (1, 0.6%). The only IRSI in a patient with normal CIAs was performed for device stenosis (4.6%). In conclusion, the Zenith endograft is effective for EVAR in patients with ectatic CIAs. Moreover, the presence of large CIAs was not associated with an increased risk of adverse iliac-related outcome or subsequent IRSI. Long-term surveillance, however, is mandatory, as IRSIs may be necessary
PMID: 15776309
ISSN: 0890-5096
CID: 79515
Subintimal angioplasty in the management of critical lower-extremity ischemia: value in limb salvage
Lipsitz, Evan C; Veith, Frank J; Ohki, Takao
The interest in and overall usage of endovascular procedures for the treatment of lower extremity ischemia continues to grow at a rapid pace. An increasing number of centers throughout the world are gaining experience with subintimal angioplasty. Promising results have been reported and the application of the technique has been expanded to include the iliac and crural arteries. The technique of subintimal angioplasty and several variations are discussed. Although primary patency rates compared with bypass are relatively low for patients undergoing subintimal angioplasty, limb salvage rates remain high. When a subintimal angioplasty fails, it frequently does so without the recurrence of symptoms, especially when a gangrenous lesion or ulcer has healed. Given the many advantages of this technique, which include reduced anesthesia requirements, a minimally invasive approach, and potential reductions in length of stay and cost, subintimal angioplasty will continue to have a role in the treatment of lower extremity ischemia. When applied judiciously, bypass options may be preserved. This does not, however, mean that the availability of this technique should be used as justification to lower the threshold for the treatment
PMID: 15952692
ISSN: 1531-0035
CID: 79512
Newly developed high attenuation within the aneurysm sac after endovascular repair of abdominal aortic aneurysm: CT observations [Meeting Abstract]
Rozenblit, AM; Prabhakar, PD; Milikow, D; Ricci, ZJ; Veith, FJ
ISI:000228717800023
ISSN: 0361-803x
CID: 80078
Discontinuous, staccato growth of abdominal aortic aneurysms
Kurvers, Harrie; Veith, Frank J; Lipsitz, Evan C; Ohki, Takao; Gargiulo, Nicholas J; Cayne, Neal S; Suggs, William D; Timaran, Carlos H; Kwon, Grace Y; Rhee, Soo J; Santiago, Christian
BACKGROUND: To evaluate whether abdominal aortic aneurysm (AAA) growth in individual patients can be characterized as continuous or discontinuous (staccato). STUDY DESIGN: From 1996 to 2002, 609 patients presented with unruptured AAAs. Of these, 278 underwent prompt repair and 331 were observed. In this study, we included 52 patients (16% of the latter group) who had at least four CT scans and were observed for 18 months or longer without any intervention. AAA growth was defined as any increase in diameter of >/= 3 mm over any observation period(s). AAA nongrowth was defined as absence of growth for at least 6 months. Staccato growth was defined as at least one period of nongrowth combined with at least one period of growth. RESULTS: The 52 patients had a mean age of 75 +/- 8 (SD) years. The mean observation period was 42 +/- 20 months and the mean AAA diameter growth rate was 3.6 +/- 2.4 mm/y. Only 12 of these 52 patients (23%) demonstrated continuous growth. Staccato growth occurred in 34 patients (65%). Six patients (12%) showed no growth at all over 18 to 57 months (mean 30 months). No correlation was observed between initial diameter of AAAs and a patient's individual growth rate during the whole observation period (R = 0.04, p = 0.46). CONCLUSIONS: Individual AAA behavior is usually characterized by periods of nongrowth alternating with periods of growth, ie, staccato growth. Some aneurysms may have long periods of nongrowth. Accordingly, management decisions cannot be based on the presumption that observed growth rates of AAAs can be extrapolated to predict future growth rates
PMID: 15501110
ISSN: 1072-7515
CID: 45469
Effects of bilateral hypogastric artery interruption during endovascular and open aortoiliac aneurysm repair
Mehta, Manish; Veith, Frank J; Darling, R Clement; Roddy, Sean P; Ohki, Takao; Lipsitz, Evan C; Paty, Philip S K; Kreienberg, Paul B; Ozsvath, Kathleen J; Chang, Benjamin B; Shah, Dhiraj M
PURPOSE: Hypogastric artery interruption is sometimes required during aortoiliac aneurysm repair. We have not experienced some of the life-threatening complications of pelvic ischemia reported by others. Therefore we analyzed our experience to identify factors that help minimize pelvic ischemia with unilateral and bilateral hypogastric artery interruption. METHODS: From 1995 to 2003, 48 patients with aortoiliac aneurysm required interruption of both hypogastric arteries as part of endovascular (n = 32) or open surgical (n = 16) repair. During endovascular aneurysm repair coils were placed at the origin of the hypogastric arteries, and bilateral hypogastric artery interruptions were staged at 1 to 2 weeks when possible. Open surgery necessitated oversewing or excluding the origins of the hypogastric arteries and extending the prosthetic graft to the external iliac or femoral artery. Collateral branches from the external iliac and femoral arteries were preserved, and patients received systemic heparinization (50 units/kg). RESULTS: There was no buttock necrosis, ischemic colitis requiring colon resection, or death with the bilateral hypogastric artery interruption. Initially buttock claudication developed in 20 patients (42%), but persisted in only 7 patients (15%) at 1 year. New onset of impotence occurred in 4 of 28 patients (14%), and there were no neurologic deficits. CONCLUSIONS: Bilateral hypogastric artery interruptions can be accomplished with limited morbidity. When hypogastric artery interruption is needed during endovascular aneurysm repair, certain principles help minimize pelvic ischemia. These include hypogastric artery interruption at its origin to preserve the pelvic collateral vessels, staging bilateral hypogastric artery interruptions when possible, preserving collateral branches from the femoral and external iliac arteries, and providing adequate heparinization of the patient during these procedures
PMID: 15472597
ISSN: 0741-5214
CID: 79517
Relationship of proximal fixation to renal dysfunction in patients undergoing endovascular aneurysm repair
Mehta, M; Cayne, N; Veith, F J; Darling, R C 3rd; Roddy, S P; Paty, P S K; Ozsvath, K J; Kreienberg, P B; Chang, B B; Shah, D M
Technological advancements have lead to dramatic improvements in stentgraft device design resulting in more trackable delivery systems and transrenal uncovered stents and barbs for better fixation. Transrenal bare-stents may limit stentgraft migration, particularly in patients with short or flared proximal aortic necks. However, potential disadvantages might be in worsening renal function, particularly in patients with preexisting renal insufficiency. We retrospectively analyzed our recent 7 year experience of patients undergoing endovascular aneurysm repair (EVAR) using a variety of stentgrafts with and without transrenal bare-stent fixation. Patients were divided into 2 groups; infrarenal fixation (IRF) vs transrenal fixation (TRF), or patients with preoperative serum Cr values that were normal (=/<1.5 mg/dl) vs slightly elevated (1.6-2 mg/dl), vs markedly elevated (2.1- 3.5 mg/dl). The exclusion criteria included patients with chronic renal insufficiency (CRI) on hemodialysis, and preoperative high-grade renal artery stenoses requiring angioplasty and stenting. Of 705 patients that underwent EVAR, 496 (IRF: 385 [78%], and TRF: 111 [22%]) were available with routine evaluations of serum Cr and CT scans. Preexisting comorbidities, mean procedure contrast volume, and postprocedure follow-up were similar in both groups. In the immediate postoperative period, mean serum Cr did not change significantly in either the IRF group (1.3+/-0.7 mg/dl to 1.2+/-0.9 mg/dl) or the TRF group (1.3+/-0.5 mg/dl to 1.3+/-0.6 mg/dl). Mean serum Cr did, however, significantly increase over longer follow-up in both groups: 1.4+/-0.8 mg/dl for IRF (P<0.03), and 1.5 +/- 0.8 mg/dl for TRF (P<0.01). Cr clearance was similarly unchanged in the immediate postoperative period (58+/-23 to 61+/-25 ml/min/1.73 m(2) for IRF group, 53+/-17 to 55+/-17 ml/min/1.73 m(2) for TRF group), but was significantly decreased in longer follow-up (53+/-23 ml/min/1.73 m(2) for IRF, p<0.02: and 48+/-16 ml/min/1.73 m(2) for TRF, P<0.01). There were no significant differences in serum Cr increase (p=0.19) or Cr clearance decrease (p=0.68) between the IRF and TRF groups. Small renal infarcts were noted in 6 patients (1.6%) in the IRF group, and in 8 patients (7%) in the TRF group (p=0.37). Of patients with normal preoperative renal function, renal dysfunction developed in 7.7% of IRF group and 6.1% of TRF group (p=0.76). In patients with preexisting CRI, renal dysfunction developed in 18.2% of IRF group, and 17.1% of TRF group (p=0.95). Eight patients with postoperative renal dysfunction, 5 (1.3%) from IRF group and 3 (2.7%) from TRF group subsequently required hemodialysis, and this difference was not statistically significant (p=0.91). We also analyzed 200 consecutive patients undergoing EVAR with intra-arterial contrast agents with and without preexisting CRI not on dialysis. The groups were identified on the basis of preprocedure serum Cr: group 1 (n=108), Cr less than 1.5 mg/dL (normal range); group 2 (n=65), Cr 1.5 to 2.0 mg/dL; group 3 (n=27), Cr 2.1 to 3.5 mg/dL. Routine precautions in patients with CRI included preoperative intravenous hydration with 2 L of normal saline solution, discontinuation of all nephrotoxic drugs, intraoperative administration of mannitol (0.5 g/kg intravenously), and use of nonionic, low osmolar intra-arterial contrast agent (Omnipaque 350). One-hundred and eight patients had normal renal function (group 1), and 92 patients had preexisting CRI with baseline Cr 1.5 to 2.0 mg/dL (group 2, n=65) or 2.1 to 3.5 mg/dL (group 3, n=27). Comorbid conditions included coronary artery disease (group 1, 51%; group 2, 49%; group 3, 59%), hypertension (group 1, 39%; group 2, 46%; group 3, 52%), and diabetes mellitus (group 1, 25%; group 2, 35%; group 3, 48%). In groups 1, 2, and 3, the mean volume of low osmolar contrast agent used was 210 cc, 160 cc, 130 cc, respectively; hemodynamic instability developed in 3, 1, and 1 patient, respectively. The incidence of postoperative complications between the 3 study groups was not statistically different. In grications between the 3 study groups was not statistically different. In group 1 a transient increase in serum Cr (>30% over baseline and >1.4 mg/dL) was noted in 3 patients (2.7%), 2 of whom (1.9%) required temporary hemodialysis and 1 (0.9%) who died of renal failure. In group 2 a transient increase in serum Cr was noted in 2 patients (3.1%); both patients (3.1%) required temporary hemodialysis, and 1 patient (1.5%) died of renal failure. In group 3 a transient increase in serum Cr was noted in 2 patients (7.4%); 1 patient (3.7%) required temporary hemodialysis, and 1 patient (3.7%) died of renal failure. Perioperative hypotension significantly increased the risk for elevated serum Cr and death (p<0.05), and larger contrast volume was associated with an increase in serum Cr (p<0.05) during the postoperative period. Following EVAR renal function declines slightly with both IRF and TRF. Our data show no overall difference between patients with IRF and TRF with respect to infarcts, decline in renal function, or onset of dialysis. There were a slightly greater number of renal infarcts in the TRF group, but these infarcts were clinically inconsequential. In patients with CRI, EVAR with intra-arterial radiographic contrast agents is believed to impair renal function, and CRI is considered a relative contraindication to the procedure. Results of our investigation indicate that risk for worsening renal insufficiency, dialysis, and death is only slightly and not significantly greater in patients with CRI compared with patients with normal renal function. With appropriate precautions of avoiding perioperative hypotension and limiting the volume of nonionic contrast agents, CRI need not be a contraindication for EVAR with intra-arterial contrast agents
PMID: 15365517
ISSN: 0021-9509
CID: 45023
The origin of species and future of a specialty: an interview with Dr. Frank Veith by Roger T. Gregory [Interview]
Veith, Frank
PMID: 15108055
ISSN: 0890-5096
CID: 79522
Predicting aneurysm enlargement in patients with persistent type II endoleaks
Timaran, Carlos H; Ohki, Takao; Rhee, Soo J; Veith, Frank J; Gargiulo, Nicholas J 3rd; Toriumi, Hisako; Malas, Mahmood B; Suggs, William D; Wain, Reese A; Lipsitz, Evan C
OBJECTIVE: The clinical significance of type II endoleaks is not well understood. Some evidence, however, indicates that some type II endoleaks might result in aneurysm enlargement and rupture. To identify factors that might contribute to aneurysm expansion, we analyzed the influence of several variables on aneurysm growth in patients with persistent type II endoleaks after endovascular aortic aneurysm repair (EVAR). METHODS: In a series of 348 EVARs performed during a 10-year period, 32 patients (9.2%) developed type II endoleaks that persisted for more than 6 months. Variables analyzed included those defined by the reporting standards for EVAR (SVS/AAVS) as well as other endoleak characteristics. Univariate, receiver operating characteristic curve, and Cox regression analyses were used to determine the association between variables and aneurysm enlargement. RESULTS: The median follow-up period was 26.5 months (range, 6-88 months). Thirteen patients (41%) had aneurysm enlargement by 5 mm or more (median increase in diameter, 10 mm), whereas 19 (59%) had stable or shrinking aneurysm diameter. Univariate and Cox regression analyses identified the maximum diameter of the endoleak cavity, ie, the size of the nidus as defined on contrast computed tomography scan, as a significant predictor for aneurysm enlargement (relative risk, 1.12; 95% confidence interval, 1.04-1.19; P =.001). The median size of the nidus was 23 mm (range, 13-40 mm) in patients with aneurysm enlargement and 8 mm (range, 5-25 mm) in those without expansion (Mann-Whitney U test, P <.001). Moreover, receiver operating characteristic curve and Cox regression analyses showed that a maximum nidus diameter greater than 15 mm was particularly associated with an increased risk of aneurysm enlargement (relative risk, 11.1; 95% confidence interval, 1.4-85.8; P =.02). Other risk factors including gender, smoking history, hypertension, need of anticoagulation, aneurysm diameter, type of endograft used, and number or type of collateral vessels were not significant predictors of aneurysm enlargement. CONCLUSIONS: In patients with persistent type II endoleaks after EVAR, the maximum diameter of the endoleak cavity or nidus is an important predictor of aneurysm growth and might indicate the need for more aggressive surveillance as well as earlier treatment
PMID: 15192552
ISSN: 0741-5214
CID: 79518