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Mark F Fillinger

Publications and source records attributed to Mark F Fillinger.

At least 19 recordsLinked to original sources
PubMed2006

Non-invasive determination of zero-pressure geometry of arterial aneurysms.

Arterial aneurysms are in a pre-deformed state in vivo under non-zero pressure. The ability to determine their zero pressure geometry may help in improving accuracy of determination of stress distribution and reverse estimation of material properties from dynamic imaging data. An approximate method to recover the zero pressure geometry of the AAA is proposed. This method is motivated by the observation that the patterns in displacement field for a given AAA are strikingly consistent in an AAA under all physiological pressures. The basic principle is to leverage this observation to iteratively identify the geometry that when subjected to the in vivo pressure, will recover the geometry reconstructed from in vivo imaging. The methodology is demonstrated and validated using patient-specific AAA models.

Aortic Aneurysm, Abdominal↗
PubMed2006

Elemental composition, morphology and mechanical properties of calcified deposits obtained from abdominal aortic aneurysms.

Calcified deposits exist in almost all abdominal aortic aneurysms (AAAs). The significant difference in stiffness between these hard deposits and the compliant arterial wall may result in local stress concentrations and increase the risk of aneurysm rupture. Calcium deposits may also complicate AAA repair by hindering the attachment of a graft or stent-graft to the arterial wall or cause vessel wall injury at the site of balloon dilation or vascular clamp placement. Knowledge of the composition and properties of calcified deposits helps in understanding the risks associated with their presence. This work presents results of elemental composition, microscopic morphology, and mechanical property measurements of human calcified deposits obtained from within AAAs. The elemental analyses indicate the deposits are composed primarily of calcium phosphate with other assorted constituents. Microscopy investigations show a variety of microstructures within the deposits. The mechanical property measurements indicate an average elastic modulus in the range of cortical bone and an average hardness similar to nickel and iron.

Aged↗
PubMed2006

Elastic and rupture properties of porcine aortic tissue measured using inflation testing.

A new inflation test device was developed to study the mechanical properties of aortic tissue. The device was used to measure failure (rupture) strength and to determine the nonlinear, anisotropic elastic properties of porcine thoracic aorta. The tester was designed to stretch initially flat, circular tissue specimens to rupture under uniform biaxial loading. Water was chosen as the pressurizing fluid. Mechanical stretch and radius of curvature during inflation were measured optically in two orthogonal directions, and the Cauchy stress components were calculated from the deformation and the applied pressure. All porcine samples that ruptured successfully did so via a tear in the circumferential direction. Thus, the failure strength was taken to be the stress in the axial direction immediately prior to rupture. The mean failure strength was 1.75 MPa and mean axial stretch at failure was 1.52. These values agree well with published data for other arterial tissues. The nonlinearly elastic deformation behavior was modeled using a hyperelastic constitutive law of the type proposed by Holzapfel et al. [Holzapfel GA, Gasser TC, Ogden RW. J Elasticity 2000;61:1-48]. The results showed that the dominant directions of anisotropy in the porcine aortas were approximately 45 degrees to the axial and circumferential directions, and that the isotropic contribution to the constitutive model was insignificant.

Animals↗
PubMed2005

Outcomes of renal artery angioplasty and stenting using low-profile systems.

OBJECTIVE: Renal artery percutaneous transluminal angioplasty (RPTA) and stenting (RAS) are accepted therapies for selected patients with renovascular hypertension and chronic renal insufficiency. We evaluated the outcomes and complications of RAS performed by vascular surgeons at our institution with modern low-profile systems. METHOD: We retrospectively analyzed all RPTA and RAS procedures attempted with the use of low-profile systems from June 2000 to September 2003. Eighty-two patients (96 arteries) with atherosclerotic renal artery stenosis were treated. Indication for treatment was hypertension in 44 (54%) and chronic renal insufficiency in 38 (46%). Technical success, complication rates, clinical success for control of hypertension or renal insufficiency, restenosis, and survival were reviewed with a mean follow-up of 1 year. RESULTS: Ninety-three arteries were treated with stents, three with RPTA only. Primary technical success was 95%, with 98% overall technical success. Major complications occurred in 6.1% and minor complications in 1.2%. Hypertension was improved in 81% at 1 year. Renal function was improved in 23%, stable in 53%, and worse in 24% at 1 year. Restenosis was seen by routine duplex surveillance in 25% at 1 year. Restenosis associated with clinical deterioration and confirmed by angiogram was seen in 10%. The overall 3-year survival was 83%. CONCLUSION: RPTA/RAS can be performed with low-profile systems with excellent technical success, low complication rates, and clinical outcomes that compare favorably with prior reports.

Angioplasty, Balloon↗
PubMed2005

Prediction of altered endograft path during endovascular abdominal aortic aneurysm repair with the Gore Excluder.

OBJECTIVE: During endovascular abdominal aortic aneurysm (AAA) repair (EVAR), the rapid deployment of the Gore Excluder endograft may be associated with anatomic shortening of the endograft path. This shortened path may result in coverage of the hypogastric artery origin or overly conservative graft length selection that may lead to unnecessary extensions. We quantified the degree of path alteration with this endograft and developed an algorithm to predict it. METHODS: Preoperative and postoperative three-dimensional (3D) computed tomographic (CT) scans were evaluated for 50 consecutive patients with Gore Excluder endografts by using 21 anatomic measurements and 6 calculated indices. Measurements were evaluated as if only 3D lumen centerline measurements were available, rather than complete 3D computer-aided measurement and "virtual graft" simulation. Tortuosity was quantitated from the renal artery to the hypogastric origin, using the difference between a straight line and the lumen centerline. RESULTS: The endograft was deployed successfully in all cases. The graft end points were typically quite close to the preoperative plan: mean renal artery-to-graft distance was within 2.0 +/- .5 mm, and the limb end point-to-hypogastric origin differed by an average of only 1.8 +/- 1.6 mm. Although accurate in most cases, the actual graft path shortened 1 cm or more relative to the centerline in 11% of limbs. On univariate analysis, determinants of alteration of >1 cm in the graft deployment path were (1) aortoiliac tortuosity (renal-to-hypogastric artery, P < .002), (2) the degree of planned graft rotation (73% of cases altered >10 mm were in the rotated position, P < .05), and (3) the insertion side (73% of alterations >or=10 mm were ipsilateral to the main device, P < .05). On multivariate analysis, the renal-to-hypogastric artery tortuosity index (RHTI) was significant ( P < .004), and device type and rotation approached significance ( P < .08). We developed a classification scheme based on RHTI to predict the risk of alteration of the graft path >or=1 cm (low risk, 0%; medium risk, 10%; high risk, 25%) and an algorithm to predict the degree of alteration of the anatomy that reduced the number of cases shortening >or=1 cm to zero. CONCLUSIONS: The graft deployment path will be altered significantly in a minority of cases with the Gore Excluder endograft, but this can cause hypogastric occlusion or other problems. Anatomic shortening is predictable from morphologic features such as tortuosity, graft insertion side, and rotation. We developed an algorithm based on a tortuosity index that quantitates the risk and degree of shortening associated with endograft deployment.

Algorithms↗
PubMed2005

Restenosis in gold-coated renal artery stents.

BACKGROUND: Gold coating improves stent visibility under fluoroscopy. This is particularly valuable for precise stent placement during renal artery stenting (RAS). There is conflicting evidence regarding restenosis with gold-coated stents. To evaluate the effect of gold coating on restenosis after renal stenting, we reviewed the results of all patients undergoing RAS in our practice. METHODS: A retrospective cohort study of all patients undergoing RAS between June 2000 and September 2003 was performed. During this time, both gold-coated and stainless steel stents were used. Restenosis (>60% diameter) was determined by serial follow-up duplex exams (peak systolic velocity >180 cm/s and renal-aortic ratio >3.5). Restenosis rates were determined by using the Kaplan-Meier life-table method. Variables potentially affecting restenosis were evaluated with the log-rank test and Cox proportional hazards modeling. RESULTS: RAS was performed in 97 arteries (78 patients). Gold-coated (NIRoyal) stents were placed in 59 arteries (48 patients). Stainless steel stents (Corinthian, Genesis, and Herculink) were placed in 38 arteries (34 patients). Patient demographics, indication for treatment, technical success, and complications did not differ between gold and stainless steel stent groups. Mean follow-up was 15 months for gold-coated stents and 18 months for stainless steel stents (NS). By life-table method, 1-year and 2-year freedom from restenosis rates were 84% and 78% in arteries treated with stainless steel stents versus 69% and 39% in those treated with gold-coated stents (P = .012, log-rank test). By multivariate analysis, only the use of gold-coated stents (P = .018; hazard ratio [HR], 3.3; 95% confidence interval [CI], 1.2 to 8.7) and bilateral disease (P = .046; HR, 2.3; 95% CI, 1.02 to 5.2) predicted restenosis. Stent diameter, patient demographics, and indication for RAS had no effect on restenosis by univariate analysis. According to American Heart Association criteria, 87% of patients in the stainless steel group had improved blood pressure at 1 year, compared with 77% in the gold-coated stent group (Kaplan-Meier; P = .042, log-rank test). There were no significant differences in the effect of RAS on serum creatinine levels between the two groups. CONCLUSION: Gold-coated renal stents had a substantially higher rate of restenosis than stainless steel stents in our series. These findings have led us to abandon the use of gold-coated stents for RAS. Patients who have received gold-coated stents for the treatment of atherosclerotic renal artery stenosis should be followed closely for evidence of restenosis.

Aged↗
PubMed2005

Mesenteric stenting for chronic mesenteric ischemia.

BACKGROUND: Mesenteric stenting has not been widely adopted for the treatment of chronic mesenteric ischemia (CMI). The recent availability of embolic protection and low-profile devices with the theoretical ability to decrease perioperative bowel necrosis, led us to begin using mesenteric stenting for patients with CMI. We review our initial experience to examine short-term outcomes. METHODS: We performed a retrospective analysis of all patients who were treated by vascular surgeons with mesenteric stenting for CMI. Patients with acute mesenteric ischemia were excluded. We evaluated perioperative morbidity and mortality, restenosis, recurrent symptoms, and reintervention. Kaplan-Meier methods were used to assess events during follow-up. We also compared these outcomes with a historical control group of patients treated with open surgical revascularization. RESULTS: Fourteen patients underwent mesenteric stenting over the past 3 years. Mean age was 73, and 64% were women. There was no perioperative or 30-day mortality or major morbidity. Early restenosis and recurrent symptoms occurred in 10% and 9% of patients at 6 months. At a mean follow-up of 13 months, 53% of patients underwent reintervention. However, 93% were symptom-free at their last follow-up. Compared with open surgery, stent patients had lower perioperative major morbidity (30% vs 0%, P < .01) and shorter hospital and intensive care unit length of stay (median 10 days vs 2 days, and 3 days vs 0 days, respectively, P < .01 for both). However, stent patients were seven times as likely to develop restenosis (P < .01), four times more likely to develop recurrent symptoms (P < .01), and 15 times more likely to undergo reintervention (P < .01). There was one death 13 months after stenting due to mesenteric infarction in a patient lost to follow-up. One patient was successfully converted to open surgery after a second restenosis. He had regained 20 pounds and was determined to be a better operative candidate than at his initial presentation. There was no perioperative or 30-day mortality or major morbidity with reintervention after mesenteric stenting. CONCLUSION: Mesenteric stenting for CMI can be performed with low perioperative risk. However, stenting is associated with early restenosis and recurrent symptoms requiring secondary procedures. Patients with severe nutritional depletion or high surgical risk may benefit from mesenteric stenting for CMI, but close follow-up is required. Later open surgery can be performed for restenosis if nutritional status and surgical risk are improved, or repeat angioplasty and stenting can be effectively performed if operative risk remains high.

Aged↗
PubMed2005

Automated methodology for determination of stress distribution in human abdominal aortic aneurysm.

Knowledge of impending abdominal aortic aneurysm (AAA) rupture can help in surgical planning. Typically, aneurysm diameter is used as the indicator of rupture, but recent studies have hypothesized that pressure-induced biomechanical stress may be a better predictor Verification of this hypothesis on a large study population with ruptured and unruptured AAA is vital if stress is to be reliably used as a clinical prognosticator for AAA rupture risk. We have developed an automated algorithm to calculate the peak stress in patient-specific AAA models. The algorithm contains a mesh refinement module, finite element analysis module, and a postprocessing visualization module. Several aspects of the methodology used are an improvement over past reported approaches. The entire analysis may be run from a single command and is completed in less than 1 h with the peak wall stress recorded for statistical analysis. We have used our algorithm for stress analysis of numerous ruptured and unruptured AAA models and report some of our results here. By current estimates, peak stress in the aortic wall appears to be a better predictor of rupture than AAA diameter. Further use of our algorithm is ongoing on larger study populations to convincingly verify these findings.

Algorithms↗
PubMed2004

Anatomic characteristics of ruptured abdominal aortic aneurysm on conventional CT scans: Implications for rupture risk.

OBJECTIVE: The purpose of this study was to analyze anatomic characteristics of patients with ruptured abdominal aortic aneurysms (AAAs), with conventional two-dimensional computed tomography (CT), including comparison with control subjects matched for age, gender, and size. METHODS: Records were reviewed to identify all CT scans obtained at Dartmouth-Hitchcock Medical Center or referring hospitals before emergency AAA repair performed because of rupture or acute severe pain (RUP group). CT scans obtained before elective AAA repair (ELEC group) were reviewed for age and gender match with patients in the RUP group. More than 40 variables were measured on each CT scan. Aneurysm diameter matching was achieved by consecutively deleting the largest RUP scan and the smallest ELEC scan to prevent bias. RESULTS: CT scans were analyzed for 259 patients with AAAs: 122 RUP and 137 ELEC. Patients were well matched for age, gender, and other demographic variables or risk factors. Maximum AAA diameter was significantly different in comparisons of all patients (RUP, 6.5 +/- 2 cm vs ELEC, 5.6 +/- 1 cm; P <.0001), and mean diameter of ruptured AAAs was 5 mm smaller in female patients (6.1 +/- 2 cm vs 6.6 +/- 2 cm; P =.007). Two hundred patients were matched for diameter, gender, and age (100 from each group; maximum AAA diameter, 6.0 +/- 1 cm vs 6.0 +/- 1 cm). Analysis of diameter-matched AAAs indicated that most variables were statistically similar in the two groups, including infrarenal neck length (17 +/- 1 mm vs 19 +/- 1 mm; P =.3), maximum thrombus thickness (25 +/- 1 mm vs 23 +/- 1 mm, P =.4), and indices of body habitus, such as [(maximum AAA diameter)/(normal suprarenal aorta diameter)] or [(maximum AAA diameter)/(L3 transverse diameter)]. Multivariate analysis controlling for gender indicated that the most significant variables for rupture were aortic tortuosity (odds ratio [OR] 3.3, indicating greater risk with no or mild tortuosity), diameter asymmetry (OR, 3.2 for a 1-cm difference in major-minor axis), and current smoking (OR, 2.7, with the greater risk in current smokers). CONCLUSIONS: When matched for age, gender, and diameter, ruptured AAAs tend to be less tortuous, yet have greater cross-sectional diameter asymmetry. On conventional two-dimensional CT axial sections, it appears that when diameter asymmetry is associated with low aortic tortuosity, the larger diameter on axial sections more accurately reflects rupture risk, and when diameter asymmetry is associated with moderate or severe aortic tortuosity, the smaller diameter on axial sections more accurately reflects rupture risk. Current smoking is significantly associated with rupture, even when controlling for gender and AAA anatomy.

Aged↗
PubMed2003

Early results of stent-grafting to treat diffuse aortoiliac occlusive disease.

INTRODUCTION: Diffuse aortoiliac occlusive disease or isolated external iliac artery occlusion >or=10 cm long typically are treated with surgical bypass grafting because of limited durability of stent placement. We evaluated the results of stent-graft placement as an option for treatment of these diseases. METHODS: Demographic data for patients undergoing stent-grafting in one or more iliac artery segments were recorded. Technical, clinical, and hemodynamic success, and aortoiliac primary and secondary patency were analyzed with Society for Vascular Surgery/American Association for Vascular Surgery criteria. RESULTS: Thirty-four consecutive patients underwent stent-graft treatment because of rest pain (65%) or tissue loss (35%). Mean patient age was 63 years, and 38% of patients were women. Ninety-one percent of patients had hypertension, 71% had coronary artery disease, 21% had renal insufficiency (serum creatinine > 2.0 mg/dL), and 26% had diabetes; 71% were active smokers. TransAtlantic Inter-Society Consensus C or D disease was present in 85% of patients, complete common or external iliac artery occlusion was present in 41%, and external iliac artery disease requiring treatment was present in 94% of patients. Mean lesion length was 13.7 +/- 8 cm. Technical, hemodynamic, and clinical success was achieved in all patients in whom the lesion could be crossed with a wire. Ankle-brachial index increased from.30 +/-.03 to.59 +/-.04. Self-expanding stent grafts were used (Wallgraft, Boston Scientific, Boston, Mass, in 88% of patients; Viabahn, W. L. Gore, Flagstaff, Ariz, in 12% of patients). Concomitant common femoral endarterectomy was performed in 53% of patients. At 12 months, primary patency was 70% and primary assisted patency was 88%. Four stent grafts became occluded because of distal external iliac artery or proximal common femoral artery disease, which required subsequent common femoral endarterectomy and either external iliac artery stent grafting or extraanatomic bypass grafting. Eighty percent (four of five) of primary patency failures were in patients who did not undergo concomitant common femoral endarterectomy at initial stent graft placement. CONCLUSION: Early results of stent-graft placement to treat diffuse aortoiliac occlusive disease appear better than our recent experience with stenting alone. Concomitant common femoral endarterectomy or better assessment of femoral disease may improve durability.

Adult↗
PubMed2003

Blinded comparison of preoperative duplex ultrasound scanning and contrast arteriography for planning revascularization at the level of the tibia.

PURPOSE: We examined whether preoperative duplex ultrasound scanning (DU) could replace contrast material-enhanced arteriography (CA) in selecting the recipient artery of tibial or peroneal artery bypass grafts. METHODS: In patients who underwent tibial or peroneal artery bypass grafting because of critical ischemia, images were obtained of the lower extremity arterial circulation with both DU and CA. Vascular surgeons, blinded to the operation performed, reviewed either DU or CA images for arterial visualization and patency. The tibial or peroneal artery best suited to receive the bypass graft was selected by surgeons using only data from either DU or CA images. This selection was compared with the artery actually used at bypass surgery. RESULTS: Preoperative DU and CA data for 40 lower extremities in 38 patients undergoing bypass grafting at the level of the tibia provided 110 arteries: 38 anterior tibial arteries, 32 peroneal arteries, and 40 posterior tibial arteries. Ten arteries (8 peroneal, 2 anterior tibial) were not identified with DU, and 1 artery (anterior tibial) was not identified with CA. DU enabled prediction of the artery actually used in 88% of patients (35 of 40), whereas CA enabled prediction of the artery actually used in 93% of patients (37 of 40; P =.59). Duplicate findings at DU and CA enabled selection of 85% of arteries actually used (95% confidence interval, 71%-93%). Arteries used for bypass grafting had significantly higher peak systolic velocity (35 cm/s vs 25 cm/s; P =.04), higher end-diastolic velocity (15 cm/s vs 9 cm/s; P =.005), and greater diameter (2.4 mm vs 1.7 mm; P =.003) compared with arteries not selected for bypass grafting. CONCLUSION: Findings at DU and CA typically agree when used to select tibial or peroneal arteries for bypass grafting. With DU there is occasional difficulty in identification of the peroneal artery, but selection of the actual artery used is accurate. Peak systolic velocity, end-diastolic velocity, and diameter characteristics correlate with arteriographic criteria for tibial bypass target artery selection. If DU enables adequate identification of a target artery for bypass grafting, and especially if the peroneal artery is seen, findings at CA are not likely to alter bypass execution.

Adult↗
PubMed2003

Endovascular repair of abdominal aortic aneurysm without preoperative arteriography.

OBJECTIVE: Clinical trials of endovascular aortic aneurysm repair (EVAR) have required both preoperative aortography and computed tomography (CT). We codeveloped specialized three-dimensional (3-D) reconstruction and computer-aided measurement, planning, and simulation software (3-D CAMPS) based on CT or magnetic resonance imaging, to eliminate the need for preoperative arteriography. METHODS: EVAR with 3-D CAMPS as the sole preoperative imaging method was performed in 196 patients from 1996 to 2001, with six endograft types in three configurations. Physical examination, abdominal radiography, and CT (3D-CAMPS) were performed at 1, 6, and 12 months, then annually. RESULTS: For a subset of cases in which a comparison could be made, 3-D CAMPS was superior to angiography for prediction of endograft length and iliac access. Hospital mortality was zero, and 30-day mortality was 0.5%. In three patients immediate conversion to open repair (1.5%) was necessary because of previously unknown stent-graft mechanical limits. Incidence of endoleak was 15% at 1 month, 10% at 6 months, 6% at 12 months, and 7% at 24 months, and 92% of endoleaks were type II. Mean follow-up was 18 months. Aneurysm-related mortality was zero. Nineteen secondary procedures (all endovascular) were performed in 16 patients (8%). For all graft types, freedom from secondary procedure was 94% at 1 year and 90% at 2 years, and this was better for endografts ultimately approved by the US Food and Drug Administration (96% at 1 year, 95% at 2 years; P =.02). No known measurement-related complications occurred in the series. Results for secondary intervention and endoleak compare favorably to series with similar endograft types. CONCLUSIONS: EVAR can be performed with 3-D CAMPS as the sole preoperative imaging method to achieve outcomes comparable to the best series published for each endograft type. CT with 3-D CAMPS can effectively eliminate the need for preoperative arteriography and avert associated morbidity, expense, and exposure to contrast agent and radiation.

Aged↗
PubMed2003

Abdominal aortic aneurysm size regression after endovascular repair is endograft dependent.

OBJECTIVE: This study was performed to determine whether abdominal aortic aneurysm (AAA) regression is different with various endografts after endovascular repair. METHODS: A four-center retrospective review of size change after endovascular AAA repair was performed. Consecutive patients with at least 1-year follow-up and available imaging studies were included. Three hundred ninety patients received either the Ancure, AneuRx, Excluder, or Talent endograft. AAA size and endoleak status were recorded from computed tomography (CT) scans at the initial postoperative follow-up visit and at 1 and 2 years thereafter. AAA size was defined as the minor axis of the infrarenal aorta on the largest axial section on the two-dimensional CT scan. A change in AAA size of 0.5 cm or greater from baseline was considered clinically significant. The effect of initial size, endoleak, and type of endograft on AAA regression was analyzed. RESULTS: Mean baseline size was significantly greater with Talent endografts and smaller with Excluder endografts. Clinically significant regression in AAA size occurred in nearly three fourths of patients with Ancure and Talent endografts at 2 years. Regression in AAA size was less frequent with the AneuRx (46%) and Excluder (44%) devices. Initial size, endoleak, and endograft type were significant predictors of regression at multivariate analysis at 1 year. However, by 2 years only endograft type was still an independent predictor of AAA shrinkage. CONCLUSIONS: Long-term morphologic changes after endovascular aneurysm repair depend on endograft type.

Aortic Aneurysm, Abdominal↗
PubMed2003

Prediction of rupture risk in abdominal aortic aneurysm during observation: wall stress versus diameter.

OBJECTIVES: We previously showed that peak abdominal aortic aneurysm (AAA) wall stress calculated for aneurysms in vivo is higher at rupture than at elective repair. The purpose of this study was to analyze rupture risk over time in patients under observation. METHODS: Computed tomography (CT) scans were analyzed for patients with AAA when observation was planned for at least 6 months. AAA wall stress distribution was computationally determined in vivo with CT data, three-dimensional computer modeling, finite element analysis (nonlinear hyperelastic model depicting aneurysm wall behavior), and blood pressure during observation. RESULTS: Analysis included 103 patients and 159 CT scans (mean follow-up, 14 +/- 2 months per CT). Forty-two patients were observed with no intervention for at least 1 year (mean follow-up, 28 +/- 3 months). Elective repair was performed within 1 year in 39 patients, and emergent repair was performed in 22 patients (mean, 6 +/- 1 month after CT) for rupture (n = 14) or acute severe pain. Significant differences were found for initial diameter (observation, 4.9 +/-.1 cm; elective repair, 5.9 +/-.1 cm; emergent repair, 6.1 +/-.2 cm; P <.0001) and initial peak wall stress (38 +/- 1 N/cm(2), 42 +/- 2 n/cm(2), 58 +/- 4 N/cm(2), respectively; P <.0001), but peak wall stress appeared to better differentiate patients who later required emergent repair (elective vs emergent repair: diameter, 3% difference, P =.5; stress, 38% difference, P <.0001). Receiver operating characteristic (ROC) curves for predicting rupture were better for peak wall stress (sensitivity, 94%; specificity,81%; accuracy, 85% [with 44 N/cm(2) threshold]) than for diameter (81%, 70%, 73%, respectively [with optimal 5.5 cm threshold). With proportional hazards analysis, peak wall stress (relative risk, 25x) and gender (relative risk, 3x) were the only significant independent predictors of rupture. CONCLUSIONS: For AAAs under observation, peak AAA wall stress seems superior to diameter in differentiating patients who will experience catastrophic outcome. Elevated wall stress associated with rupture is not simply an acute event near the time of rupture.

Aged↗
PubMed2002

Epidural anesthesia and analgesia: effects on recovery from cardiac surgery.

OBJECTIVE: To measure predefined clinical effects resulting from the use of epidural anesthesia and analgesia during and after cardiac surgery. DESIGN: Prospective, randomized, nonblinded clinical trial. SETTING: Single academic medical center. PARTICIPANTS: Sixty patients scheduled for elective cardiac surgery with cardiopulmonary bypass. INTERVENTIONS: Sixty participants were randomly assigned to 1 of 2 study groups: (1) A control group received general anesthesia during surgery and intravenous opiate analgesia after surgery. (2) A treatment group received thoracic epidural anesthesia combined with general anesthesia during surgery and epidural analgesia for the first 24 postoperative hours. MEASUREMENTS AND MAIN RESULTS: Primary study measurements were planned to evaluate recovery from surgery and included time to tracheal extubation, duration of postoperative intensive care unit stay, duration of postoperative hospitalization, pain control, urinary free cortisol, cardiopulmonary complication rate, and total hospital charges. No statistically significant differences between the 2 study groups were found in these main measurements. CONCLUSIONS: The clinical course of elective cardiac surgical patients who receive epidural anesthesia during surgery and epidural analgesia after surgery is comparable to that of patients managed with general anesthesia alone during surgery followed by parenteral opiate analgesia after surgery.

Analgesia, Epidural↗
PubMed2002

Early results of external iliac artery stenting combined with common femoral artery endarterectomy.

PURPOSE: The endovascular approach to external iliac artery (EIA) disease extending into the common femoral artery (CFA) has been avoided because of problems with stent placement across the inguinal ligament. Surgical treatment for this disease distribution includes extensive endarterectomy or bypass procedures or both. We report our initial experience with a combined open and endovascular approach to these patients. METHODS: We performed a retrospective analysis of all patients who underwent intraoperative EIA stenting after CFA endarterectomy/patch angioplasty between 1997 and 2000. Stents were positioned to end at the proximal endarterectomy endpoint, without crossing the inguinal ligament. Technical success, hemodynamic success, and clinical success were determined according to Society of Vascular Surgery/International Society of Cardiovascular Surgery criteria. Life-table analysis was performed for patency. RESULTS: Thirty-four patients (mean age, 68 years; 23 male, 11 female) had combined endovascular and open treatment of iliofemoral occlusive disease. Indications were claudication in 41% and critical limb ischemia in 59%. Femoral reconstruction included endarterectomy with patch angioplasty in all patients. EIA stent deployment incorporated the stenotic iliac segment and the proximal endpoint of the endarterectomy in all patients. Four patients (12%) also needed common iliac angioplasty at the same time for proximal iliac disease, and 14 patients (41%) also needed distal revascularization for associated femoropopliteal or tibial disease. Technical success and hemodynamic success were achieved in 100% of patients. Clinical success was achieved in 97% of patients. The mean postoperative increase in ankle-brachial index in patients with inflow procedures only was 0.36 (range, 0.1 to 0.85). The overall complication rate was 15%. With a mean follow-up period of 13 months (range, 0.5 to 28 months), 1-year primary patency and primary-assisted patency rates were 84% and 97%, respectively. No perioperative mortality was seen. CONCLUSION: EIA stenting as an adjunct to CFA endarterectomy/patch angioplasty allows for more localized surgery than conventional bypass. This approach also allows a better interface between the stent and endarterectomy than staged preoperative stenting. Technical success and early patency rates are excellent.

Aged↗