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Biomedical subjects

Evan C Lipsitz

Publications and source records attributed to Evan C Lipsitz.

At least 19 recordsLinked to original sources

Discontinuous, staccato growth of abdominal aortic aneurysms.

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.

Aged↗

System to decrease length of stay for vascular surgery.

OBJECTIVES: Reduction of length of stay (LOS) is critical for optimal use of hospital resources. We developed and evaluated a system to aggressively reduce LOS for vascular surgery. METHOD: Key to this system, which we introduced on January 1, 2001, was appointment of a LOS officer, who communicated daily during hospitalization with patients and families about discharge planning, organized outpatient services for wound care and rehabilitation to transition patients quickly to nonhospital care, and had biweekly meetings with relevant paramedical services. LOS for 509 patients operated on in 2000 (standard group) was compared with LOS for 474 operated on in 2001 and 595 patients operated on in 2002 (LOS reduction groups). Data for all patients with aortic aneurysm, carotid artery stenosis, lower extremity critical ischemia or amputation, and foot debridement were included. RESULTS: LOS in 2000 averaged 8.5 days, compared with 5.9 days in 2001 and 5.6 days in 2002. All decreases in LOS for each diagnostic category in 2001 and 2002 were statistically significant (P = <.001-.03). There was no significant increase in readmission rate (2.2% vs 1.9% and 2.0%, respectively), mortality rate (0.8% vs 0.6% and 0.7%, respectively), or percent of patients who received endovascular treatment (18% vs 16% and 14%, respectively). These decreases in LOS saved the hospital more than US dollars 616200 in 2001, and US dollars 847550 in 2002 (US dollars 500/patient-day). CONCLUSIONS: A committed LOS officer with major specific daily responsibilities for decreasing LOS and discharging patients resulted in a 31% to 33% decrease in LOS, with important cost savings to the hospital and no negative effect on patient care.

Aged↗

Variability of maximal aortic aneurysm diameter measurements on CT scan: significance and methods to minimize.

OBJECTIVES: We noted substantial differences when measuring repeatedly the same abdominal aortic aneurysm (AAA) on the same computed tomography (CT) scan. This study quantitated this variability, and methods to minimize it were developed. METHODS: The CT maximal diameter of 25 AAAs was measured by eight experienced observers, including six vascular surgeons and two radiologists, using two methods: an unstandardized protocol, and a standardized protocol using fine calipers to carefully measure the largest diameter perpendicular to the estimated aneurysm centerline, from outer aneurysm wall to outer wall. The average measurement difference between observers was calculated for each method. The average difference between each observer's measurement and the official radiology report value was also calculated. Agreement between the two measurement methods was assessed with Bland-Altman plots. RESULTS: The difference in maximal diameter measurements between each observer averaged 4.0 +/- 5.1 mm (range, 0.0-35.0 mm) with the unstandardized method. The mean measurement difference with the standardized protocol was significantly lower, and averaged 2.8 +/- 4.4 mm (range, 0.0-26.0 mm; P<.05). Measurements taken from the official radiology report differed from each of the observer's standardized measurement by an average of 5.0 +/- 6.3 mm (range, 0.0-28.0 mm). This difference was similar for both the unstandardized and standardized methods. Bland-Altman plots confirmed the wide variation of the maximal diameter measurements when the unstandardized method was compared with the standardized method (95% confidence interval, -9-9 mm). CONCLUSIONS: Routine CT maximal diameter measurement of AAAs can have substantial interobserver variability. Standardized measurement protocols can decrease, but not eliminate, this measurement variability. Thus apparent size changes based on CT measurements may represent measurement artifact rather than actual aneurysm growth or shrinkage, particularly when a standardized system is not used.

Aortic Aneurysm, Abdominal↗

Predicting aneurysm enlargement in patients with persistent type II endoleaks.

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.

Aged↗

Effects of bilateral hypogastric artery interruption during endovascular and open aortoiliac aneurysm repair.

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.

Aged↗

Is elevated creatinine level a contraindication to endovascular aneurysm repair?

PURPOSE: It is widely believed that chronic renal insufficiency (CRI) greatly increases the risk associated with endovascular abdominal aortic aneurysm repair (EVAR) and is a relative contraindication to the procedure and to the use of intra-arterial contrast agents (IACA). We reviewed a 5-year EVAR experience to determine whether the procedure and use of IACA have an important deleterious effect on renal function in patients with and without pre-existing CRI. METHODS: Endovascular aneurysm repair (EVAR) was performed in 200 patients with a variety of endografts, with intra-arterial contrast agents. The patients were retrospectively assigned to three groups on the basis of preoperative serum creatinine concentration (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. No patients had undergone hemodialysis. In groups 2 and 3, patients received hydration perioperatively, and received mannitol intraoperatively; no nephrotoxic drugs were administered during the procedure, other than nonionic contrast agent (Omnipaque 350). RESULTS: The incidence of postoperative complications between the three 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 three patients (2.7%), two of whom (1.9%) required temporary hemodialysis and one (0.9%) who died of renal failure. In group 2 a transient increase in serum Cr was noted in two patients (3.1%); both patients (3.1%) required temporary hemodialysis, and one patient (1.5%) died of renal failure. In group 3 a transient increase in serum Cr was noted in two patients (7.4%); one patient (3.7%) required temporary hemodialysis, and one patient (3.7%) died of renal failure. Perioperative hypotension significantly increased the risk for elevated serum Cr and death (P <.05), and larger contrast volume was associated with an increase in serum Cr (P <.05) during the postoperative period. CONCLUSIONS: EVAR with intra-arterial contrast agents can be accomplished in patients with chronic renal insufficiency who do not require dialysis, with limited and acceptable morbidity and mortality, similar to that observed with open aneurysm repair. Contrary to other reports in which perioperative precautions were not used, our study shows that with EVAR the risk for worsening renal failure, dialysis, and death is only slightly, and not significantly, greater in patients with preoperative chronic renal insufficiency compared with patients with normal renal function. Perioperative hypotension and increased contrast volume are significant risk factors for postoperative increase in serum Cr and death. With appropriate precautions such as averting perioperative hypotension and limiting the volume of nonionic contrast agents, elevated Cr need not be a contraindication to EVAR with intra-arterial contrast agents.

Aged↗

Subintimal angioplasty for chronic arterial occlusions.

Percutaneous treatment of peripheral arterial disease has evolved greatly. The prevalence of superficial femoral artery occlusions has necessitated new devices and techniques to treat these patients percutaneously. Presently several therapies are available or under investigation. These range from stents, drug eluting stents, covered stents, cryoangioplasty, laser recanilization, blunt micro dissection, and subintimal angioplasty. This paper will discuss the indications, technique, and results of subintimal angioplasty.

Angioplasty, Balloon↗

Fate of collateral vessels following subintimal angioplasty.

PURPOSE: To evaluate the fate of collateral vessels adjacent to and within the target lesion following subintimal angioplasty (SIA). METHODS: Pre and postprocedural angiograms were reviewed for 29 patients undergoing SIA of the lower extremity arteries over a 3-year period. The number of patent collateral vessels </=5 cm proximal to the occlusion (proximal segment) and </=5 cm distal to the occlusion (distal segment) were recorded pre and postprocedurally and compared. In addition, the number of collateral vessels that were re-opened within the recanalized segment following SIA was counted. RESULTS: The mean number of patent collaterals in the proximal segment was 1.9 (range 0-4) preprocedurally and 1.4 (range 0-4) postprocedurally (p<0.002). The mean number of patent collaterals in the distal segment was 1.9 (range 0-4) pre-procedurally and 1.0 (range 0-4) postprocedurally (p<0.0001). Previously absent collaterals within the recanalized segment were observed in 4 (14%) of 29 patients post-SIA. The mean number of collateral vessels within all 3 segments (proximal, treated, and distal) was 3.9 collaterals preprocedurally and 2.9 collaterals postprocedurally. CONCLUSIONS: Some collateral vessels are sacrificed during SIA, but the majority are preserved. In addition, SIA has the potential to open new collaterals within the occluded segment. These collaterals may play an important role should restenosis develop within the target segment.

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Delayed open conversion following endovascular aortoiliac aneurysm repair: partial (or complete) endograft preservation as a useful adjunct.

OBJECTIVES: The purpose of this study was to review our experience with delayed open conversion (>30 days) following endovascular aortoiliac aneurysm repair (EVAR) and to introduce the concept and advantages of endograft retention in this setting. METHODS: From January 1992 to January 2003, a total of 386 EVARs using a variety of endografts were successfully deployed. Eleven (2.8%) patients required delayed conversion to open repair at an average of 30 months (range, 10-64). Data from all patients undergoing both EVAR and open conversion were prospectively collected. RESULTS: EVARs were performed using grafts made by Talent (4), Vanguard (2,) AneuRx (1), and Surgeon (4). Conversion to open repair (9 transabdominal, 1 retroperitoneal, 1 transabdominal plus thoracotomy) was performed for aneurysm rupture in 7 patients (4 type 1 endoleak, 2 type 2 endoleak, 1 aortoenteric fistula) and aneurysm enlargement in 4 patients (1 type 1 endoleak, 1 type 2 endoleak, 1 type 3 endoleak, 1 endotension). Patients with aneurysm rupture were treated on an emergent basis. Complete removal of the endograft with supraceliac cross-clamping was performed in two cases. One patient (rupture) did not survive the operation, and one patient (aortoenteric fistula) died 2 weeks postoperatively. In the remaining nine cases, the endograft was either completely (1) or partially (6) removed, or left in situ (2). Supraceliac balloon control (2), supraceliac clamping (1), suprarenal clamping (1), or infrarenal clamping (5) was used in these cases. All nine of these patients survived the operation. In one procedure in which the endograft was left intact (endotension), repair was accomplished by exposing the endograft and by placing a standard tube graft over it as a sleeve. In the second procedure in which the graft was left in situ (rupture), the graft was well incorporated, and bleeding lumbar arteries were oversewn and the sac was closed tightly over the endograft. In the remaining 7 cases, the endograft was transected and the proximal portion only (6) or the proximal and distal portions (1) were excised. All surviving patients continue to do well and remain without complications associated with the endograft remnant at a mean follow-up of 22 months (range, 3-56) from the time of open conversion and 46 months (range, 10-73) from the time of original EVAR. CONCLUSIONS: Open repair in the setting of a long-standing endograft offers several unique technical challenges but can be successfully accomplished in most patients. Preservation of all or part of the endograft is possible in many patients. This technique simplifies the operative approach and is preferred over complete endograft removal if possible.

Aged↗

Open aneurysm repair at an endovascular center: value of a modified retroperitoneal approach in patients at high risk with difficult aneurysms.

OBJECTIVE: This study was undertaken to evaluate elective open abdominal aortic aneurysm (AAA) repair and the role of a modified retroperitoneal approach in a high-volume endovascular center. METHODS: We reviewed prospectively collected data for 175 elective infrarenal open AAA repairs performed over 6 years. A transperitoneal approach was used in 118 procedures, and a modified retroperitoneal approach was used in 57 procedures. The incisional modification, which facilitated repair in patients with massive obesity, scarring, or ventral hernia, included a higher, more posterolateral location in the ninth intercostal space. Risk factors that added to the difficulty of the repair included aneurysms with a short (<1 cm) or no aortic neck in 45 patients; large, angled or flared aortic neck in 32 patients;, tortuous and calcified iliac arteries in 6 patients; morbid obesity in 10 patients; low ejection fraction (15%-30%) in 14 patients; chronic obstructive pulmonary disease, with forced expiratory volume at 1 second less than 55% in 4 patients; previous laparotomy in 18 patients; previous left-sided colectomy in 11 patients; large right iliac aneurysm in 8 patients; large ventral hernia in 8 patients; pelvic irradiation in 4 patients; failed endovascular repair in 5 patients; and previous failed open repair attempt in 2 patients. Many of these factors occurred with significantly greater frequency (P =.04-.001) in the retroperitoneal group. All factors were correlated with outcome. RESULTS: Despite these risk factors, overall 30-day mortality was 3.5% (retroperitoneal group, 3.8%), and mean length of hospital stay was 9 days (retroperitoneal group, 8 days). There was no significant correlation between mortality or length of stay and any of the mentioned risk factors (P >.2). CONCLUSION: In the era of endovascular aneurysm exclusion, open AAA repair is generally used to treat anatomically complex or difficult aneurysms, many of which are present in patients at high risk. Despite this combination of anatomic and systemic risk factors, the modified retroperitoneal approach facilitates treatment in difficult circumstances and enables open AAA repair to be performed with acceptable mortality and morbidity.

Academic Medical Centers↗

Does transrenal fixation of aortic endografts impair renal function?

OBJECTIVES: Transrenal fixation (TFX) of aortic endografts is thought to increase the risk for renal infarction and impaired renal function. We studied the late effects of TFX on renal function and perfusion. METHODS: Of 189 patients with commercial aortic endografts, which we inserted between 1995 and 2002, we reviewed data for 130 patients (112 men, 18 women) with available creatinine (Cr) concentration and contrast enhanced computed tomography (CT) scans preoperatively and 1 to 97 months after the procedure. Of the 130 patients, 69 patients had TFX and 61 patients had infrarenal fixation (IFX). Both groups were physiologically comparable. Average age was 76 +/- 8 years for patients with TFX and 75 +/- 8 years for patients with IFX. Presence of renal infarct or renal artery occlusion was determined by nephrograms on serial contrast-enhanced CT scans. RESULTS: Mean follow-up was 17 +/- 16 months (range, 1-54 months) for TFX and 21 +/- 21 months (range, 1-97 months) for IFX. Mean serum Cr concentration increased significantly during long-term follow-up in both groups (TFX, 1.3 +/- 0.5 mg/dL to 1.5 +/- 0.8 mg/dL, P <.01; IFX, 1.3 +/- 0.7 mg/dL to 1.4 +/- 0.8 mg/dL, P <.03). Creatinine clearance (CrCl) similarly decreased over long-term follow-up in both groups (TFX, 53.3 +/- 17.7 mL/min/1.73 m(2) to 47.9 +/- 16.2 mL/min/1.73 m(2), P <.01; IFX, 58.1 +/- 22.7 mL/min/1.73 m(2) to 53.1 +/- 23.4 mL/min/1.73 m(2), P <.02). There were no significant differences in the increase in Cr concentration (P =.19) or decrease in CrCl (P =.68) between TFX and IFX groups. Small renal infarcts were noted in four patients (5.8%) in the TFX group and one patient (1.6%) in the IFX group. No increase in Cr concentration or decrease in CrCl was noted in any patient with a renal infarct. Postoperative renal dysfunction developed in 7 of 69 patients (10.1%) in the TFX group and 7 of 61 patients (11.5%) in the IFX group. There were no statistically significant differences between groups with respect to number of patients with new renal infarcts (P =.37) or postoperative renal dysfunction (P =.81). CONCLUSION: There is a slight increase in serum Cr concentration and decrease in CrCl after aortic endografting. However, there was no significant difference in these changes between patients with TFX and IFX. Although TFX may produce a higher incidence of small renal infarcts, these do not impair renal function. Thus our midterm results suggest that TFX can be performed safely, with no greater change in renal function than observed after IFX.

Aged↗

Endovascular abdominal aortic aneurysm repair to prevent rupture in a patient requiring lithotripsy.

Extracorporeal shock wave lithotripsy (ESWL) for urolithiasis may result in rupture of a coexistent abdominal aortic aneurysm (AAA). We report a patient who required ESWL and who had an AAA. Open surgery was precluded by morbid obesity and persisting incisional hernias after mesh repair. Endovascular AAA repair (EVAR) with bifurcated grafts was precluded by an 11-mm distal aorta. EVAR with stacked tubular AneuRx components was performed, followed by ESWL. The AAA was excluded, and the integrity and position of the endografts were not altered by ESWL.

Aged↗

Treatment of ruptured abdominal aneurysms with stent grafts: a new gold standard?

Ruptured abdominal aortoiliac aneurysms, when treated with open surgical repair, have high morbidity and mortality rates. Since 1994, the authors have used endovascular approaches to treat this entity. Patients with presumed ruptured aortoiliac aneurysms were treated with restricted fluid resuscitation (hypotensive hemostasis), transport to the operating room, placement under local anesthesia of a brachial or femoral guide wire into the supraceliac aorta, and arteriography. If aortoiliac anatomy was suitable, an endovascular graft (stent-graft) repair was performed. If the anatomy was unfavorable, standard open repair was performed. Only if circulatory collapse occurred was a supraceliac balloon placed and inflated using the previously positioned guidewire. Of 35 patients treated in this manner, 29 underwent endovascular graft repair, and 6 required open repair. Four patients died within 30 days (operative mortality rate, 11%). Only 10 patients required supraceliac balloon control. Endovascular grafts, when combined with hypotensive hemostasis and other endovascular techniques including proximal balloon control, may improve treatment outcomes with ruptured abdominal aortoiliac aneurysms. The authors believe these techniques will become widely used for the treatment of ruptured aneurysms.

Angioplasty↗

Digital fluoroscopy as a valuable adjunct to open vascular operations.

The increasing availability of and vascular surgeons' familiarity with digital cine-fluoroscopy in the operating room has been facilitated by the advent and growing popularity of endovascular aortoiliac aneurysm repair and other endovascular techniques that are being incorporated into vascular surgical practice. Digital cine-fluoroscopy can also be used as a valuable adjunct to standard open vascular procedures in several ways including: performance of completion angiography, fluoroscopically-assisted thromboembolectomy, intraoperative planning angiography, fluoroscopically-guided pressure gradient measurements, achieving vascular control of proximal arteries, intraoperative thrombolysis of compromised outflow tracts, and angioplasty and stenting of lesions detected intraoperatively. These techniques can improve the outcome of standard vascular procedures by permitting the identification of inflow, outflow, conduit, and anastomotic defects intraoperatively and guiding their repair. Additionally, in many cases they can reduce the amount of exposure required, reduce intraoperative blood loss, and minimize trauma to vessels during thrombectomy. Fluoroscopic guidance can facilitate and improve these and other aspects of standard open vascular procedures. Conversely, the ability to perform open interventions can facilitate the performance of many endovascular interventions. It is becoming increasingly important to be facile with both open and E fluoroscopically guided techniques in order to fully treat the spectrum of vascular disease in an optimum fashion.

Angiography↗

Endovascular grafts and other catheter-directed techniques in the management of ruptured abdominal aortic aneurysms.

Abdominal aortoiliac aneurysms that are ruptured and treated with open surgical repair have high morbidity and mortality rates. We have employed endovascular approaches to treat this entity since 1994. Patients with presumed ruptured aortoiliac aneurysms were treated with restricted fluid resuscitation (hypotensive hemostasis), transport to the operating room, placement under local anesthesia of a brachial or femoral guidewire into the supraceliac aorta and arteriography. If aortoiliac anatomy was suitable, an endovascular graft repair was performed. If the anatomy was unfavorable, the aneurysm was repaired in a standard open fashion. Only if circulatory collapse occurred was a supraceliac balloon placed and inflated using the previously positioned guidewire. Of 36 patients so managed, 30 underwent endovascular graft repair and six required open repair. Four patients died within 30 days (operative mortality = 11%). Only 10 patients required supraceliac balloon control. Endovascular grafts, when combined with hypotensive hemostasis and other endovascular techniques, including proximal balloon control, may improve treatment outcomes with ruptured abdominal aortoiliac aneurysms. These techniques should become widely used for the treatment of ruptured aneurysms.

Aneurysm, Ruptured↗

Significance of endotension, endoleak, and aneurysm pulsatility after endovascular repair.

OBJECTIVE: The lack of aneurysm pulsatility after endovascular aneurysm repair (EVAR) is deemed by some an important guide to the effectiveness of exclusion. However, factors that contribute to aneurysm pulsatility after EVAR have not been elucidated. This study quantitatively analyzed the effects of systemic pressure, aneurysm sac pressure, endoleak, branch outflow from aneurysm sac, and intra-sac thrombus on aneurysm pulsatility after EVAR. METHODS: In an ex vivo model, an artificial aneurysm sac was incorporated within a mock circulation comprised of rubber tubing and a pulsatile pump. The aneurysm sac was then completely excluded from the circulatory circuit with two types of stent-grafts, ie, supported and unsupported, and heparinized canine blood was circulated. Systemic circulation and aneurysm sac pressure was recorded in the absence and presence of endoleaks, and simulated open and closed lumbar branch outflow from the aneurysm sac. The aneurysm sac was then filled with organized human thrombus, and all pressure measurements were repeated. Two observers blinded to the above-mentioned variables independently evaluated aneurysm sac pulsatility with palpation in five separate experiments. Analysis of variance was performed, with significance accepted at P =.05. RESULTS: Systemic pressure was simulated in the artificial circulation to range from 100/60 to 180/60 mm Hg. Regardless of the simulated lumbar branch outflow from the aneurysm, sac pressure was directly related to the presence of endoleak (P <.001). Aneurysm sac pulsatility was present only when the lumbar branch outflow was patent and not dependent on sac pressures. Aneurysm sac thrombosis or type of stent-graft did not influence sac pressure and pulsatility. CONCLUSIONS: In this model, after EVAR pulsatility depends on aneurysm sac outflow, regardless of endoleak, sac thrombosis, sac pressure, or stent-graft. Furthermore, persistent pulsatility does not predict systemic intra-sac pressure, nor does lack of pulsatility reflect freedom of the aneurysm sac from systemic pressurization. This ex vivo model suggests that aneurysm pulsatility is an unreliable guide for predicting aneurysm sac pressurization after EVAR. Other diagnostic methods must be used to assess successful aneurysm exclusion.

Anastomosis, Surgical↗

Does subintimal angioplasty have a role in the treatment of severe lower extremity ischemia?

OBJECTIVE: Subintimal angioplasty (SIA) has been advocated to treat long segment lower extremity arterial occlusions, but many question its value. We evaluated the role of SIA in a group of patients with severe lower extremity arterial occlusive disease. METHODS: During a 2.5-year period, 39 patients with arterial occlusions (median length, 8 cm; range, 2 to 31 cm) were treated on an intention-to-treat basis with SIA. Twenty-five patients had gangrene, five had rest pain, and nine had disabling (<one block) claudication. There were 24 superficial femoral, two superficial-femoral-popliteal, four popliteal, two popliteal-tibial, five tibial, and two external iliac artery lesions. With fluoroscopic guidance, via a prograde common femoral artery puncture (n = 29) or a contralateral common femoral artery puncture (n = 9), a subintimal dissection plane was created across the occlusion with a standard guidewire and catheter. The arterial lumen was reentered distal to the occlusion, and the recanalized segment balloon was dilated. All patients were followed prospectively with arterial duplex scan. RESULTS: SIA was technically successful in 34 of 39 patients (87%). All five failures were from an inability to reenter the patent lumen distally. These five patients underwent successful bypasses that in no case were more distal than would have been required before SIA. In the 34 technically successful SIAs, pain completely resolved (14/14) and areas of gangrene (21/25) healed. The cumulative patency rate in patients who underwent successful SIA was 74% +/- 10% at 12 months. The mean increase in ankle-brachial index after SIA was 0.34 (range, 0.1 to 0.69). There were two distal embolic events, successfully treated surgically (n = 1) or with catheter-directed techniques (n = 1). Three patients underwent subsequent bypass, and the remaining five patients remain asymptomatic. CONCLUSION: SIA is feasible and can be effective in some patients with lower extremity arterial occlusions and threatened limbs. These results, plus SIA's many advantages, support an increasing role for it in the treatment of lower extremity arterial occlusive disease.

Aged↗