Biomedical subjects

Ellen D Dillavou

Publications and source records attributed to Ellen D Dillavou.

12 recordsLinked to original sources

PubMed2006

A decade of change in abdominal aortic aneurysm repair in the United States: Have we improved outcomes equally between men and women?

OBJECTIVES: Abdominal aortic aneurysm (AAA) repair has undergone vast changes in the last decade. We reviewed a national database to evaluate the effect on utilization of services and rupture rates. METHODS: From the Centers for Medicare Services (CMS), a 5% inpatient sample was obtained for 1994 to 2003 as beneficiary encrypted files (5% BEF) and as a limited data set file after 2001. Files were translated into Microsoft Access by using a custom program. Queries were performed using International Classification of Diseases (9th Revision) (ICD-9) diagnosis codes 441.3 (ruptured AAA) or 441.4 (non-ruptured AAA) and ICD-9 procedure codes 38.34, 38.36, 38.44, 38.64, 39.25, 39.52 for open, and 39.71 (available after October 2000) for endovascular repair. The 5% BEF totals were multiplied by 20 to calculate yearly volumes. Total cases were divided into the yearly CMS population of elderly Medicare recipients for repair rates per capita and are reported as cases per 100,000 elderly Medicare recipients. Statistics were performed using chi2, Student's t test, nonparametric tests, and multiple regression analysis; P < or = .05 was considered significant. RESULTS: Elective AAA repairs declined from 94.4/100,000 in 1994 to 87.7/100,000 in 2003. AAA rupture surgery declined from 18.7/100,000 (1994) to 13.6/100,000 (2003). Rupture repairs from 1994 to 2003 decreased by 29% for men and by 12% for women (P < .001). Rupture mortality has not changed, but the average is significantly higher for women at 52.8%, with men averaging 44.2% (P < .001). Mortality for elective AAA repair has decreased from 5.57% (1994) to 3.20% (2003) in men (P < .001) and from 7.48% (1994) to 5.45% (2003) in women (P < .001). Multivariate analysis demonstrated increasing age, female sex, and open surgery (vs endovascular) were significant predictors of elective and ruptured AAA repair mortality. For 2003 elective AAA repairs, the average length of stay was 6.9 days in men and 8.9 days in women (P < .01) For 2003, men were more likely to be discharged to home after rupture (32.9% of men vs 23.3% of women; P < .001) and elective repair (84.5% of men vs 70.1% of women; P < .001). CONCLUSIONS: Improvements in AAA management in the last decade have decreased aneurysm-related deaths and reduced the incidence of aneurysm ruptures, with a lower utilization of services. Women, however, continue to have a consistently higher mortality for open and ruptured AAA repair and are less likely to return to home after either.

Age Factors↗

PubMed2006

Improving aneurysm-related outcomes: nationwide benefits of endovascular repair.

OBJECTIVES: Endovascular aneurysm repair (EVAR) has changed the practice of abdominal aortic aneurysm (AAA) surgery. We examined a national Medicare database to establish the effect of EVAR introduction into the United States. METHODS: A 5% random sample of inpatient Medicare claims from 2000 to 2003 was queried using International Classification of Diseases, 9th Revision (ICD-9) diagnosis and procedure codes. An EVAR procedure code was available after October 2000. Occurrences were multiplied by 20 to estimate yearly national volumes and then divided into the yearly Centers for Medicare and Medicaid Services (CMS) population of elderly Medicare recipients for rates per capita, reported as cases per 100,000 elderly Medicare recipients. Statistical analysis was performed by using chi2, Student's t test, nonparametric tests, and multiple regression analysis, with significance defined as P < or = .05. RESULTS: Elective AAA repairs averaged 87.7 per 100,000 Medicare patients between 2000 and 2003, with EVAR has steadily increasing to 41% of elective repairs in 2003. From 2000 to 2003, overall elective AAA mortality declined from 5.0% to 3.7% (P < .001), while open repair mortality remained unchanged. EVAR patients are significantly older than patients treated with open repair. From 2000 to 2003 patients >84 years receiving EVAR increased to 62.7% (P < .001). Overall hospital length of stay (LOS) decreased from 8.6 days in 2000 to 7.3 days in 2003, P < .001, but increased for open AAA patients. EVAR patients were more likely to be discharged home rather than to skilled facilities. Average elective repair hospital charges were not different between groups, but Medicare reimbursement was lower for EVAR, with a higher proportion cases classified as DRG 111 (major cardiovascular procedure without complications). EVAR was used in 10.6% of ruptured AAA repairs in 2003, with a significant reduction in mortality compared with open repairs for rupture (31.8% vs 50.8%; P < .001). CONCLUSIONS: EVAR is replacing open surgery without an increase in overall case volume. EVAR is responsible for overall decrease in operative mortality even in ruptured aneurysms while decreasing utilization variables. Reimbursement to hospitals is shrinking, however.

Aged↗

PubMed2006

Endovascular management of isolated iliac artery aneurysms.

OBJECTIVE: We reviewed our experience with endovascular treatment of isolated iliac artery aneurysms (IAAs). METHODS: Medical records for consecutive patients undergoing endovascular IAA repair from 1995 to 2004 were reviewed. Computed tomography (CT) angiograms were used to assess IAA location, size, and presence of endoleaks after endovascular repair. Rates of primary patency and freedom from secondary interventions were estimated using the Kaplan-Meier life-table method. RESULTS: From July 1995 to November 2004, 45 patients (42 men), with a mean age of 75 years, underwent endovascular repair of 61 isolated IAAs: 41 common iliac, 19 internal iliac, and one external iliac. Five patients (11%) were symptomatic, although none presented with acute rupture. The mean preoperative IAA diameter was 4.2 +/- 1.7 cm. Fifteen patients (33%) had prior open abdominal aortic aneurysm repair. Local or regional anesthesia was used in 28 cases (62%). Thirty-four patients (75%) were treated with unilateral iliac stent-grafts, eight (18%) with bifurcated aortic stent-grafts, and three (7%) with coil embolization alone. Perioperative major complications included one early graft thrombosis that eventually required conversion to open repair and one groin hematoma that required operative evacuation. On follow-up, late complications included one additional graft thrombosis and one late death after amputation. No late ruptures occurred after endovascular repair, with a mean follow-up of 22 months (range, 0 to 60 months). The mean postoperative length of stay was 1.3 +/- 1.0 days. On postoperative CT scans obtained at 1, 6, 12, 24, and 36 months, aneurysm shrinkage was noted in 18%, 29%, 57%, 67%, and 83% of IAAs, respectively, compared with the baseline diameter. One hypogastric aneurysm enlarged in the presence of a later identified type II endoleak. Five endoleaks were noted (4 type II, 1 indeterminate) at 1 month, with four other endoleaks (1 type II, 1 type III, 2 indeterminate) identified on later CT scans. At 2 years, primary patency was 95%, and freedom from secondary interventions was 88%. CONCLUSIONS: Endovascular repair of isolated IAAs appears safe and effective, with initial results similar to those after endovascular abdominal aortic aneurysm repair.

Aged↗

PubMed2006

Gender-related differences in the tensile strength of abdominal aortic aneurysm.

A recent study investigated the association of gender with the growth rate of AAAs and found a significant increase in the growth rate of AAAs in women than in men. On the basis of these observations, we hypothesize that there are gender-associated differences in AAA wall integrity and mechanical strength. The purpose of this study was to explore this hypothesis by comparing the tensile strength of freshly resected AAA tissue specimens between women and men. Seventy-six rectangular specimens (20 mm long x 5 mm wide) from 34 patients (24 male, 10 female) were excised from the anterior wall of patients undergoing open repair of their abdominal aortic aneurysm and tested in a uniaxial tensile tester. Ultimate tensile strength (UTS) was taken as the peak stress obtained before specimen failure. While there were no statistical differences in strength between specimens taken from male and female patients, there was a trend toward a decrease in strength in females as compared to males (87.6 +/- 6.7 N/cm(2) vs. 67.6 +/- 8.1 N/cm(2), p = 0.09). To the authors knowledge this work represents the first report of differences in biomechanical properties as a function of gender. The nearly significant decrease in UTS in women versus men reported here may be important in assessing the risk of rupture in AAA. Further testing is warranted to confirm the current trends.

Aortic Aneurysm, Abdominal↗

PubMed2005

Endovascular treatment of thoracic aortic aneurysms: results of the phase II multicenter trial of the GORE TAG thoracic endoprosthesis.

OBJECTIVE: A decade after the first report of descending thoracic aortic aneurysm (DTA) repair with endografts, a commercial device is yet to be approved in the United States. The GORE TAG endoprosthesis, an investigational nitinol-supported expanded polytetrafluoroethylene tube graft with diameters of 26 to 40 mm, is the first DTA device to enter phase II trials in the United States and has been used worldwide for a host of thoracic pathologies. METHODS: A multicenter prospective nonrandomized phase II study of the GORE TAG endoprosthesis was conducted at 17 sites. Enrollment was from September 1999 to May 2001. Preoperative workup included arteriography and spiral computed tomography scans of the chest, abdomen, and pelvis. Follow-up radiographs and computed tomography scans were obtained at 1, 6, and 12 months and yearly thereafter. RESULTS: A total of 139 (98%) of 142 patients had a successful implantation of the device. Inadequate arterial access was responsible for the 3 failures. The mean DTA size was 64.1 +/- 15.4 mm. Men slightly outnumbered women (57.7%), with an average age of 71 years, and 88% of the patients were white. Ninety percent were American Society of Anesthesiologists category III or IV. One device was used in 44% of patients, and 56% required two or more devices to bridge the thoracic aorta. The left subclavian artery was covered in 28 patients, with planned carotid-subclavian transposition. The procedure time averaged 150 minutes, estimated blood loss averaged 506 mL, intensive care unit stay averaged 2.6 days, and hospital stay averaged 7.6 days. Within 30 days, 45 (32%) patients had at least 1 major adverse event: 5 (4%) experienced a stroke, 4 (3%) demonstrated temporary or permanent paraplegia, 20 (14%) experienced vascular trauma or thrombosis, and 2 (1.5%) died. Mean follow-up was 24.0 months. Four patients had aneurysm-related deaths. Three patients underwent endovascular revisions for endoleak. No ruptures have been reported. Twenty wire fractures have been identified in 19 patients; 18 (90%) of these occurred in the longitudinal spine, and only 1 patient required treatment. At 2 years, aneurysm-related and overall survival rates are 97% and 75%, respectively. CONCLUSIONS: The GORE TAG thoracic endoprosthesis provides a safe alternative for the treatment of DTAs, with low mortality, relatively low morbidity, and excellent 2-year freedom from aneurysm-related death. Longitudinal spine fractures have so far been associated with rare clinical events.

Adult↗

PubMed2005

Is abdominal aortic aneurysm repair appropriate in oxygen-dependent chronic obstructive pulmonary disease patients?

BACKGROUND: The life expectancy of patients with oxygen-dependent chronic obstructive pulmonary disease (COPD) is significantly reduced, but the risk of any intervention is considered prohibitive. However, severe COPD may increase the risk of abdominal aortic aneurysm (AAA) rupture. We reviewed our experience with AAA repair in oxygen-dependent patients to determine whether operative risk and expected long-term survival justify surgical intervention. METHODS: A retrospective review of 44 consecutive patients with oxygen-dependent COPD undergoing AAA repair over an 8-year period was performed. Information was recorded for survival, length of follow-up, patient age, medical comorbidities, pulmonary function tests, and operative approach. Survival data were analyzed by Kaplan-Meier curves and compared with published cohorts of oxygen-dependent patients and the natural history of untreated aneurysms. RESULTS: Twenty-four patients underwent endovascular aneurysm repair (EVAR), and 20 underwent open procedures (14 retroperitoneal and 6 transabdominal). The mean AAA diameter was 6.1 cm (range, 5-9.5 cm). The mean age was 71.4 years, and 82% of patients were male. Operative mortality was 0%. The mean length of stay was 11.2 days for open procedures and 4.3 days for EVAR (significantly longer than that for standard-risk patients). The mean survival time was 37.9 months (range, 2-91 months). Preoperative medical comorbidities, type of repair, and pulmonary function tests were not predictive of survival. Postoperative morbidity was significantly higher with open repair. Long term survival was comparable to historical series of the natural history of O2 dependent patients without AAA but better than untreated 6 cm AAA cohorts. At 42 months, almost 50% of patients in our study group were still alive, compared to 20% survival at 34 months for those with untreated 6 cm AAAs. CONCLUSIONS: It is reasonable to continue to offer AAA repair to home oxygen-dependent COPD patients who are ambulatory and medically optimized and who are without untreated coronary artery disease. Although EVAR may be the most suitable treatment for oxygen-dependent COPD patients, our results show that even open repair may be safely performed in this population, with acceptable results.

Aged↗

PubMed2004

Late abdominal aortic aneurysm enlargement after endovascular repair with the Excluder device.

OBJECTIVES: Behavior of the abdominal aortic aneurysm (AAA) sac after endovascular abdominal aortic aneurysm repair (EVAR) is graft-dependent. The Excluder endograft has been associated with less sac regression than some other stent grafts. Long-term follow-up has not been reported. METHODS: Between May 1999 and July 2002, 50 patients underwent EVAR with the Excluder bifurcated endoprosthesis. These patients were followed up prospectively with computed tomography (CT) at 1, 6, and 12 months and yearly thereafter. One immediate conversion to open surgery and three deaths occurred within 6 months. One additional patient was lost to follow-up. The remaining 45 patients, 35 men and 10 women, were followed up for at least 1 year, and form the basis for this report. Their mean age was 73 +/- 5.5 years. The minor axis diameter at the largest area of the AAA on CT examination was compared with the baseline measurement at 1 month and to the smallest size previously recorded during follow-up. Change in sac size of 5 mm or greater was considered significant. Mean follow-up was 2.7 +/- 1.2 years (range, 1-4 years). Nominal variables were compared with the chi(2) test, and continuous variables with the Student t test. RESULTS: A significant decrease in average AAA sac diameter was observed at 6-month, 1-year, and 2-year follow-up. These differences were lost by the 3-year evaluation, because of delayed sac growth (n = 9) and re-expansion of once shrunken aneurysms (n = 3). The probability of freedom from sac growth or re-expansion at 4 years was only 43%. At last follow-up, sac expansion occurred in the absence of active endoleak in nine patients. Type II endoleak was associated with sac expansion in three patients (P =.003), resulting in one conversion to open surgery after the 4-year follow-up. No graft migrations, AAA ruptures, or aneurysm-related deaths were noted. CONCLUSIONS: Late aneurysm sac growth or re-expansion after EVAR with the Excluder device is common, even in the absence of endoleak. Although the incidence of important clinical sequelae is low at this point, the incidence of aneurysm expansion should be taken into consideration during the risk-benefit assessment before EVAR repair with the Excluder device.

Aged↗

PubMed2003

Does hostile neck anatomy preclude successful endovascular aortic aneurysm repair?

OBJECTIVES: Poor outcomes have been reported with endovascular aneurysm repair (EVAR) in patients with hostile neck anatomy. Unsupported endografts with active fixation may offer certain advantages in this situation. We compared EVAR results using the Ancure (Guidant) endograft in patients with and without hostile neck anatomy. METHODS: Records of EVAR patients from October 1999 to July 2002 at a tertiary care hospital were retrospectively reviewed from a division database. Patients with elective open abdominal aortic aneurysm (AAA) repair during the same period were reviewed to determine those unsuitable for EVAR. Hostile neck anatomy, assessed by computer tomography (CT) scans and angiograms, was defined as one or more of the following: (1) neck length </=10 mm, (2) focal bulge in the neck >3 mm, (3) >2-mm reverse taper within 1 cm below the renal arteries, (4) neck thrombus > or =50% of circumference, and (5) angulation > or =60 degrees within 3 cm below renals. RESULTS: Three hundred and twenty-two patients underwent EVAR with an average follow-up of 18 months. Patients in Phase II trials (n = 41), repaired with other graft types (n = 48), or without complete anatomic records (n = 27) were excluded. Demographics and co-morbidities were similar in the 115 good-neck (GN) and 91 bad-neck (BN) patients except for age (mean, 72.9 years GN vs 75.7 BN; P = 0.13), gender (11% female GN vs 22% BN; P =.04); neck length (mean, 21.8 mm GN vs 14.4 mm BN: P <.001), and angulation (mean, 22 degrees GN vs 40 degrees BN; (P <.001). Perioperative mortality (0 GN vs 1.1% BN), late mortality (5.2% GN vs 4.4% BN), all endoleaks (19.1% GN vs 17.6% BN), proximal endoleaks (0.8% GN vs 2.1% BN), and graft migration (0 for both groups) did not reach statistical significance. Neck anatomy precluded EVAR in 106 of 165 (64%) patients with open AAA. CONCLUSIONS: Unsupported endografts with active fixation can yield excellent results in treating many medically compromised patients with hostile neck anatomy. Nonetheless, an unsuitable neck remains the most frequent cause for open abdominal AAA.

Aged↗

PubMed2003

Minimally invasive parathyroidectomy: 101 consecutive cases from a single surgeon.

BACKGROUND: Intraoperative rapid parathyroid hormone (iPTH) assay is changing parathyroid surgery. One surgeon's experience at a tertiary care hospital was followed as minimally invasive parathyroidectomy (MIP) was adopted. STUDY DESIGN: In this prospective case study, patients underwent technitium 99m sestamibi scanning, iPTH monitoring, and MIP. A sestamibi-directed incision was made, and iPTH was measured preincision, preexcision of abnormal gland(s), and at 5- and 10-minute intervals. MIP was complete after gland(s) was excised and iPTH fell to less than 50% of preoperative levels. Routine discharge was on the day of surgery with daily calcium and calcitriol to minimize outpatient hypocalcemia. Secondary and tertiary hyperparathyroidism patients were excluded. RESULTS: From December 1999 to June 2002, 101 patients underwent MIP. Patients were 27% men and 73% women, with two reoperations. Preoperation laboratory results averaged serum calcium 11.08 (normal 8.5 to 10.5 mg/dL) and parathyroid hormone (PTH) 169 pg/mL (normal 10 to 55 pg/mL). Average iPTH values at operative intervals were 152, 151, 68, and 50 pg/mL, respectively. Operation demonstrated 12% of patients had four-gland hyperplasia, 3% had double adenomas, 2% had parathyroid carcinomas, and 83% had single adenomas. Discharge on the day of surgery occurred in 83% of single-adenoma patients. Postoperative laboratory results averaged calcium 9.4 mg/dL (p < 0.001 versus preoperation) and PTH 48 pg/mL (p < 0.001). Fifteen patients (16%) had elevated PTH after operation, but without elevated calcium levels. One patient had persistant hyperparathyroidism. CONCLUSIONS: MIP with iPTH monitoring is a safe and effective means of treating hyperparathyroidism. This approach allows for limited dissection and early discharge for the majority of patients.

Adolescent↗

PubMed2003

Two-dimensional versus three-dimensional CT scan for aortic measurement.

PURPOSE: To examine if 3-dimensional (3D) reconstructions of computed tomographic (CT) data, by imaging perpendicular to blood flow, can improve aortic diameter measurement accuracy over axial (2D) CT. METHODS: Two independent, blinded observers used electronic calipers to measure the minor axis and the line perpendicular to it on 40 2.5-mm 2D CT scans from 31 patients. A circular electronic tool was used to estimate diameters on 3D reconstructions from the same 40 scans. Measurements of the aortic neck were obtained 5 mm below the renal arteries and the widest slice of the aneurysm was used to measure sac diameter. Only the minor axis was measured at the iliac arteries immediately above the left (LI) and right (RI) iliac bifurcations. Datasets were compared with an intraclass correlation coefficient (ICC), Bland and Altman variation assessments, and absolute differences. RESULTS: ICC between 2D and 3D scans demonstrated high correlation with 2D minor axis measurements (neck=0.9282, sac=0.8956, RI=0.8755, LI=0.7381). 3D to 2D major axis correlation was lower (neck=0.6388, sac=0.8995). Variation between 3D and 2D minor axis measurements was low (0.51-mm average variation from the mean for the minor axis and 1.30-mm variation for the major axis). Average absolute difference between 3D and 2D diameters was 1.01 mm (minor axis) versus 2.61 mm (major axis). Interobserver correlation was highest for sac measurements both in 2D minor axis (ICC=0.8990) and 3D (ICC=0.9518). CONCLUSIONS: Minor axis measurements on axial CT scan can substitute for diameters obtained from 3D reconstructions in most clinical situations.

Aortic Aneurysm, Abdominal↗

PubMedDate not supplied

Is neck dilatation after endovascular aneurysm repair graft dependent? Results of 4 US Phase II trials.

Long-term success of endovascular aneurysm repair (EVAR) relies on a stable proximal neck. The authors' goal was to determine whether neck dilatation after EVAR varies among 4 different endografts and whether it is related to complications of the proximal neck. Core laboratory data from 4 phase II trials of aortic endografts were analyzed for neck diameter changes over time. Patients who had at least 24 months' follow-up were included in the analysis. Neck measurement methodology varied among the 3 core labs used. Values are reported within the parameters used by each lab. Short-axis neck diameter close to 5 mm below the renal arteries, when available, was used for longitudinal comparisons. Dilation was defined as an enlargement of 3 mm or more from the first postoperative scan to the last available follow-up for each patient. Graft migration and late proximal endoleaks were determined by the individual core labs. A limited number of Lifepath grafts had most recent follow-up measurements performed by the authors. Results were compared by using Student's t test, chi-square analysis, and the Pearson correlation coefficient. Postoperative measurements from 729 EVAR patients were examined. Follow-up ranged from 24 to 60 months for 229 Ancure (Guidant) and 258 AneuRx (Medtronic) patients, and from 24 to 36 months for 211 Excluder (Gore) and 31 first-generation Lifepath (Edwards) patients. Neck dilation was noted in 124 patients (17.0%) and did not differ significantly among graft types. The incidences of late proximal endoleaks were similar among graft types, but rates of migration differed (p=0.01). Dilation was associated with migration in Ancure (p=0.03) and Excluder (p=0.02) grafts. Late proximal endoleaks were seen in 4.1% of patients with and in 0.7% of patients without dilation (p=0.001). Patients with initial neck diameter >25 mm had significantly less dilatation than those with smaller necks (p<0.001). The incidence of neck dilation approached 20% in all EVAR patients after 24 months and was not significantly different among graft types. Neck dilation of 3 mm or more appears to be one risk factor for migration and late proximal endoleak.

Aortic Aneurysm, Abdominal↗

PubMedDate not supplied

Can computed tomography scan findings predict "impending'' aneurysm rupture?

Several findings on computed tomography (CT) scans of intact aneurysms have been taken to suggest "imminent'' or "impending'' aneurysm rupture. Often these are identified incidentally in asymptomatic patients when an urgent operation was not planned and may even be ill advised. The authors evaluated whether these signs can truly predict short-term aneurysm rupture. A computerized medical archival system was reviewed from August 1994 to August 2004. Patients with aortic aneurysms and official CT scan reports of "impending rupture'' were reviewed. CT films and reports were reviewed for aneurysm characteristics, while computerized medical records were reviewed for patient demographics, comorbidities, symptoms, documented subsequent rupture, and operative findings. Signs of "impending rupture'' included the crescent sign, discontinuous circumaortic calcification, aortic bulges or blebs, aortic draping, and aortic wall irregularity. Rupture occurring within 2 weeks of the index CT was defined as supporting the "imminent'' label. Forty-five patients with aortic aneurysms and CT stigmata of "impending rupture'' were identified. Five patients with additional signs of suspicious leak and 1 with an infected previously repaired aneurysm were excluded. Of 39 intact aneurysms, 26 (67%) were infrarenal, 2 (5%) were suprarenal, and the remaining 11 (28%) were thoracoabdominal. The patient group had more women than expected (19/39, 49%) and larger aneurysms (mean diameter, 6.8 +/- 1.4 cm). Mean age was 74 years. Ten patients underwent elective repair within the first 2 weeks after the index CT scan (mean, 4 days), precluding adequate observation for early rupture. None had intraoperative signs of rupture. Early rupture: 2 of the 29 remaining patients ruptured within 72 hours of the CT scan, for a positive predictive value of 6.9%. One additional patient ruptured 7 months later after declining an early intervention. No Rupture: 26 patients were observed an average of 246 days (range, 14 days to 3 years) without evidence of rupture. Fourteen were repaired electively 2 weeks to 3 years after the index CT scan, and 12 never underwent repair, mostly because of severe associated comorbidities, and were observed a mean of 394 days without rupture. Although they should be taken seriously, CT signs of "impending rupture'' alone are poor predictors of short-term aortic aneurysm rupture, and alternative terminology is needed until better predictors can be identified.

Aged↗