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Rodney A White

Publications and source records attributed to Rodney A White.

33 records · Page 2Linked to original sources
PubMed2004

Current status of thoracic aortic endograft repair.

The advent and success of endovascular repair of abdominal aneurysms had led to the development of catheter-based techniques to treat thoracic aortic pathology. Such diseases, including thoracic aortic aneurysms, acute and chronic type B dissections,penetrating aortic ulcers, and traumatic aortic transection, challenge surgeons to perform complex operative repairs in high-risk patients. The minimally invasive nature of thoracic endografting may provide an attractive alternative therapy especially in patients deemed unfit for thoracotomy. A worldwide review of thoracic endografting demonstrates encouraging short- and midterm outcomes with significant reductions in morbidity and early mortality.Long-term surveillance will be crucial to discover complications unique to thoracic endovascular interventions and to determine which patients are appropriate candidates for stent-graft therapy.

Angioplasty↗
PubMed2004

Basics of intravascular ultrasound: an essential tool for the endovascular surgeon.

The concept of catheter-based ultrasound imaging was first introduced in the early 1970s. Since its inception, intravascular ultrasound (IVUS) technology has become more user-friendly because of improvements in both the catheters and computer-driven imaging platforms. IVUS catheters enable luminal and transmural cross-sectional imaging of coronary and peripheral blood vessels with high-dimensional accuracy and detailed information about lesion morphology. With the advent of endovascular techniques in both the coronary and peripheral vasculature, IVUS has emerged as a useful and necessary adjunct. In addition to providing diagnostic information, IVUS enables optimal choice of appropriate angioplasty technique, endovascular device guidance, and controlled assessment of the efficacy of interventions. In this review we discuss the design and function of available IVUS catheters, imaging techniques and interpretation, and the present and future clinical utility in peripheral endovascular interventions.

Forecasting↗
PubMed2003

Accuracy of three-dimensional simulation in the sizing of aortic endoluminal devices.

The purpose of this study is to examine the accuracy of a 3D simulation generated by inclusion of various intensity-selected portions of spiral CT data into a proprietary software program (Preview, Medical Media Systems, MMS) in preoperative and postoperative assessment of the anatomical features of abdominal aortic aneurysm (AAA). The accuracy of this software was measured against two other modalities-intravascular ultrasound (IVUS) and axial CT scan-using the IVUS as the reference. Eighty-five patients were included; 43 underwent AAA endovascular exclusion with Talent devices, and 42 with Aneurx devices. Measurement of proximal neck diameter was performed using IVUS, Preview software, and axial CT scan with manual calipers. Measurement of the AAA maximum diameter was performed using Preview software and axial CT scan; 253 measurements in the 85 patients were included. These measurements were compared by means of both linear regression and Bland-Altman agreement analysis. Our results showed that the 95% confidence interval between the Preview software and mean IVUS measurement of proximal AAA neck (3.1 and 2.5) is narrow enough for the software to be used in sizing AAA. This would be especially important for having the properly sized devices available preoperatively. The Preview software tended to be more accurate than CT scans although it was not statistically significant.

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PubMed2003

Cardiac risk stratification in patients undergoing endoluminal graft repair of abdominal aortic aneurysm: a single-institution experience with 365 patients.

OBJECTIVE: Patients undergoing abdominal aortic aneurysm repair have a high incidence of coexisting cardiac disease. The traditional cardiac risk stratification for open abdominal aortic aneurysm surgery may not apply to patients undergoing endoluminal graft exclusion. The purpose of this study was to examine predictive risk factors for perioperative cardiac events. METHODS: As part of multiple prospective endograft trials approved by the US Food and Drug Administration, data for 365 patients who underwent endoluminal graft repair from 1996 to 2001 were collected. Variables included for analysis were age and sex; history of smoking; presence of hypertension, diabetes mellitus, or renal insufficiency; Eagle clinical cardiac risk factors; American Society of Anesthesiologists index; type of anesthesia administered; estimated blood loss; preoperative hemoglobin level; preoperative use of beta-blocker therapy; duration of surgery; need for iliac artery conduit; and concomitant other vascular procedures. Univariate and multivariate logistic regression analysis were used to determine which variables were predictive of an adverse perioperative cardiac event, eg, Q wave and non-Q wave myocardial infarction (MI), congestive heart failure (CHF), severe arrhythmia, and unstable angina. RESULTS: The study cohort included 322 men and 43 women (mean age, 74.2 years). Fifty-two (14.2%) postoperative cardiac events occurred: severe dysrhythmia in 15 patients (4.1%), MI in 14 patients (3.8%), non-Q wave MI in 8 patients (2.2%), CHF in 8 patients (2.2%), and unstable angina in 7 patients (1.9%). Univariate analysis demonstrated that age 70 years or older (P =.034), history of MI (P =.018), angina (P =.004), history of CHF (P <.001), two or more Eagle risk factors (P <.001), and lack of use of preoperative beta-blocker therapy (P =.005) were predictors of perioperative cardiac events. Multivariate analysis identified only age 70 years or older (P =.026), history of MI (P =.024) or CHF (P =.001), and lack of use of preoperative beta-blocker therapy (P =.007) as independent risk factors for an adverse cardiac event. CONCLUSIONS: Age 70 years or older, history of MI or CHF, and lack of use of preoperative beta-blocker therapy are independent risk factors for perioperative cardiac events in patients undergoing endoluminal graft repair.

Adrenergic beta-Antagonists↗
PubMed2003

Volume regression of abdominal aortic aneurysms and its relation to successful endoluminal exclusion.

OBJECTIVES: Evaluating the success of endoluminal repair of abdominal aortic aneurysms (AAAs) is frequently based on diameter measurements and determining the presence of endoleaks. The use of three-dimensional volumetric data and observation of morphologic changes in the aneurysm and device have been proposed to be more appropriate for postdeployment surveillance. The purpose of this study was to analyze the long-term volumetric and morphologic data of 161 patients who underwent endovascular AAA exclusion and to assess the utility of volume measurements for determining successful AAA repair. METHODS: Patients with spiral computed tomography scans obtained preoperatively, within the first postoperative month, at 6 months, and annually thereafter, were included in this analysis. Computerized interactive three-dimensional reconstruction of each AAA scan was performed. Total aneurysm sac volume was measured at each time interval (mean preoperative volume 169.0 +/- 78.5 mL), and the significance of volume changes was determined by mixed linear modeling, a form of repeated measures analysis, to account for longitudinal data clustered at the individual level. Sixty-two patients (38%) developed endoleaks at some time during follow-up-15 type I leaks, 45 type II leaks, and 2 type III leaks. The patients with type I and type III leaks were treated with cuffs, and the type II leaks were treated either with observation, side-branch embolization, or required open conversion. RESULTS: Aneurysm sac volume increased slightly at 1-month follow-up (+3.3%), and then decreased steadily to -12.9% at 5 years (P <.0001). This effect remained unchanged after controlling for the three device types used in our study population. Patients who did not exhibit an endoleak (n = 99) showed a significant decrease in aneurysm volume across the entire follow-up duration when compared with those who did exhibit an endoleak (n = 62) (P <.0001). The presence of a 10% or greater decrease in volume at 6 months demonstrated a sensitivity of 64%, a specificity of 95%, a positive predictive value of 95%, a negative predictive value of 62%, and an accuracy of 75% for predicting primary clinical success defined by successful deployment of the device; freedom from aneurysm- or procedure-related death; freedom from endoleak, rupture, migration, or device malfunction; or conversion to open repair. CONCLUSIONS: Volumetric analysis may be used to predict successful endoluminal exclusion of AAAs. Volume regression appears to be device-independent and should be expected in most clinically successful cases. The presence of volume increases in the first 6 months is suspicious for an endoleak that is pressurizing the aneurysm sac and heralds the need for closer evaluation and possible intervention. A volume decrease of 10% or greater at 6 months and continuing regression over time is associated with successful endovascular repair.

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PubMed2003

Stent graft migration after endovascular aneurysm repair: importance of proximal fixation.

OBJECTIVE: We reviewed the incidence of stent-graft migration after endovascular aneurysm repair in a prospective multicenter trial and identified factors that may predispose to such migration. METHODS: All patients who received treatment during the course of the multicenter AneuRx clinical trial were reviewed for evidence of stent-graft migration over 5 years, from 1996 to 2001. Post-deployment distance from the renal arteries to the proximal end of the stent graft and the proximal fixation length (length of the infrarenal neck covered by the stent graft) were determined in patients for whom pre-procedure and post-procedure computed tomography scans were measured in an independent core laboratory. RESULTS: Stent-graft migration was reported in 94 of 1119 patients, with mean time after device implantation of 30 +/- 11 months. Freedom from migration was 98.6% at 1 year, 93.4% at 2 years, and 81.2% at 3 years (Kaplan-Meier method). Subset (n = 387) analysis revealed that initial device deployment was lower in 47 patients with migration, as evidenced by a greater renal artery to stent-graft distance (1.1 +/- 0.7 cm), compared with 340 patients without migration (0.8 +/- 0.6 cm; P =.006) on post-implantation computed tomography scan. Proximal fixation length was shorter in patients with migration (1.6 +/- 1.4 cm) compared with patients without migration (2.3 +/- 1.4 cm; P =.005). There was significant variation in migration rate among clinical sites (P <.001), ranging from 0% to 30% (median, 8%), with a greater than twofold difference in migration rate between the lowest quartile (6%) and the highest quartile (15%) clinical sites. Univariate and multivariate analysis revealed that renal artery to stent-graft distance (P =.001) and proximal fixation length (P =.005) were significant predictors of migration, and that each millimeter increase in distance below the renal arteries increased risk for subsequent migration by 5.8% and each millimeter increase in proximal fixation length decreased risk for migration by 2.5%. Pre-implantation aortic neck length, neck diameter, degree of device oversizing, correct versus incorrect oversizing, device type (stiff vs flexible), placement of proximal extender cuffs at the original procedure, and post-procedure endoleak were not significant predictors of migration. Migration was treated with placement of extender modules in 23 patients and surgical conversion in 7 patients; 64 patients (68%) with migration have required no treatment. CONCLUSIONS: Stent-graft migration among patients treated in the AneuRx clinical trial appears to be largely related to low initial deployment of the device, below the renal arteries, and short proximal fixation length. Significant variation in migration rate among clinical sites highlights the importance of the technical aspects of stent-graft deployment. Advances in intraoperative imaging and deployment techniques that have been made since completion of the clinical trial facilitate precision of device placement below the renal arteries and should increase proximal fixation length. Whether this, together with increased iliac fixation length, will result in lower risk for migration remains to be determined in long-term follow-up studies.

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PubMed2003

Results from the Endologix PowerLink multicenter trial.

The Endologix PowerLink system is a one-piece, bifurcated, fully supported endoluminal graft for the treatment of abdominal aortic aneurysms (AAA). In a recently completed multicenter trial, the device has proven to be effective with a high technical success rate, low morbidity and mortality rates, and a mean decrease in AAA size over time. A 16-month mean follow-up has found low endoleak and migration rates. There have been no ruptures to date. The Endologix PowerLink device compares favorably with previously published results of other endoluminal grafts.

Angioplasty↗
PubMed2003

An alternative anesthetic technique for the morbidly obese patient undergoing endovascular repair of an abdominal aortic aneurysm.

UNLABELLED: Abdominal aortic aneurysms have been treated by open operative repair for many years. A frequent rate of morbidity is associated with the natural history of abdominal aortic aneurysms in combination with open surgical repair. Recently a new technique that is less surgically invasive has been developed as an alternative to open repair. The present case report outlines a less invasive anesthetic technique for the morbidly obese patient. IMPLICATIONS: This case report discusses a minimally invasive anesthetic approach towards the morbidly obese patient undergoing endovascular abdominal aortic aneurysm repair. It demonstrates a safe and cost-effective means of managing a patient with numerous comorbidities. We also discuss an anesthetic/surgical approach on how to provide maximum analgesia with minimal anesthesia.

Adult↗
PubMed2002

Endovascular exclusion of abdominal aortic pathology in patients with concomitant malignancy.

The advent of endoluminal aortic repair has gained increasing popularity as an alternative to traditional open surgery in the setting of multiple comorbid disease states. This study analyzes a single center experience of excluding aortic disease in patients with concomitant malignancy. As part of a Federal Drug Administration FDA-approved trial, 318 patients underwent aortic stent-graft repair between June 1996 and February 2001. During that period five patients with advanced-stage neoplasia were treated. Endovascular management of symptomatic abdominal aortic aneurysms (AAA) with a mean diameter of 7.8 cm (range, 6-10 cm), was performed in four patients. In the fifth patient, a custom-made aortic prosthesis was utilized to exclude a paraanastamotic abdominal aneurysm (PAAA) from a previous open AAA repair. Malignancies included esophageal, lung, renal, prostate, and urinary bladder cancers. A mean follow-up of 10.1 months was available. Successful endoluminal repair was accomplished in all five patients with minimal in-hospital morbidity. Mean length of stay was 3.4 days. There were no device-related mortalities and no persistent endoleaks detected for the duration of follow-up. Aneurysm sac enlargement was not seen in any of the patients and complete resolution of the PAAA was noted at one year. Exclusion of AAA and other aortic pathology in patients with an associated malignancy can be performed with a relatively low procedure-related morbidity and mortality. In this population, stent-graft repair remains an individualized option with a multidisciplinary team necessary to explore this therapeutic approach.

Aged↗
PubMed2002

Nature and significance of endoleaks and endotension: summary of opinions expressed at an international conference.

OBJECTIVE: Endoleaks and endotension are critically important complications of some endovascular aortic aneurysm repairs (EVARs). For the resolution of controversial issues and the determination of areas of uncertainty relating to these complications, a conference of 27 interested leaders was held on November 20, 2000. METHODS: These 27 participants (21 vascular surgeons, five interventional radiologists, one cardiologist) had previously answered 40 key questions on endoleaks and endotension. At the conference, these 40 questions and participant answers were discussed and in some cases modified to determine points of agreement (consensus), near consensus (prevailing opinion), or disagreement. RESULTS: Conference discussion added two modified questions for a total of 42 key questions for the participants. Interestingly, consensus was reached on the answers to 24 of 42 or 57% of the questions, and near consensus was reached on 14 of 42 or 33% of the questions. Only with the answers to four of 42 or 10% of the questions was there persistent controversy or disagreement. CONCLUSION: The current endoleak classification system with some important modifications is adequate. Types I and II endoleak occur after 0 to 10% and 10% to 25% of EVARs, respectively. Many (30% to 100%) type II endoleaks will seal and have no detrimental effect, which never or rarely occurs with type I endoleaks. Not all endoleaks can be visualized with any technique, and increased pressure (endotension) can be transmitted through clot. Aneurysm pulsatility after EVAR correlates poorly with endoleaks and endotension. An enlarging aneurysm after EVAR mandates surgical or interventional treatment. These and other conclusions will help to resolve controversy and aid in the management of these vexing complications and should also point the way to future research in this field.

Aortic Aneurysm↗
PubMed2002

Endovascular management of blunt traumatic renal artery dissection.

PURPOSE: To describe the importance of accurate diagnosis and successful emergent endovascular repair of intimal injury to the renal artery from sudden deceleration. CASE REPORT: A 22-year-old man was evaluated after jumping head first out of a fourth floor window. Gross hematuria was detected at the initial assessment. Contrast-enhanced computed tomography (CT) revealed diminished uptake in the right kidney. Arteriographic examination of the renal artery demonstrated 2 areas of intimal disruption, which a team of physicians decided to treat with angioplasty and stent placement owing to the associated intracranial injuries. Two balloon-expandable stents were successfully deployed to exclude the intimal defects. Once the associated injuries were also addressed, the patient made an uneventful recovery. CONCLUSIONS; Management of blunt traumatic injuries to the renal vasculature involves timely assessment to maximize preservation of renal function. In the setting of multiple concomitant injuries, recent experience supports the consideration of endoluminal intervention for traumatic renal artery dissections.

Adult↗
PubMed2002

Stent-graft migration following endovascular repair of aneurysms with large proximal necks: anatomical risk factors and long-term sequelae.

PURPOSE: To evaluate the outcome of aortic endografts deployed in large infrarenal necks and to identify any association of preoperative aneurysm characteristics and postoperative morphological changes with the incidence of neck dilatation and device migration in this patient subset. METHODS: The records of 47 patients (41 men; mean age 74, range 55-84) with large aortic neck diameters treated with Talent stent-grafts from 1998 to 2001 were reviewed. Patients with anatomical criteria that precluded aneurysm exclusion with currently available devices were preferentially selected. Mean baseline aneurysm morphology included 27.6-mm (range 18-33.4) suprarenal and 28.1-mm (range 24-34) infrarenal neck diameters; the infrarenal neck length was 26 +/- 16 mm with angulation of 37 degrees +/- 18 degrees. Computed tomographic (CT) angiograms up to 3 years were analyzed using specialized interactive software; migration was defined as >1-cm change in the distance from the lower renal artery to the top of the device. Pre- and postoperative morphological characteristics of the aneurysm were compared between patients with and without migration. RESULTS: Of the 45 patients successfully treated, 40 had complete CT data for analysis. During a mean 17-month follow-up, 7 (17.5%) of the 40 devices exhibited distal migration. Six patients required secondary procedures; 5 were in the migration cohort. No preoperative anatomical characteristic or degree of neck dilatation over time was predictive of stent-graft migration. Aneurysm sac regression was significant at 1 (-0.09 +/- 4.90 mm) and 2 (-1.48 +/- 2.56 mm) years in endografts without migration (p<0.001). Distal endograft migration >1 cm predicted the need for secondary interventions (p<0.001), with 83% sensitivity and 94% specificity. CONCLUSIONS: Endovascular repair is successful in patients with large infrarenal necks and complex neck morphology. Changes in aneurysm remodeling over time were similar to reported observations in patients with more favorable neck criteria. Although no anatomical factor associated with migration could be identified from this analysis, distal displacement >1 cm correlated with the need for a secondary intervention.

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PubMed2002

Endovascular exclusion of leaking thoracic aortic aneurysms.

PURPOSE: To describe the endovascular exclusion of leaking thoracic aortic aneurysms (TAA). CASE REPORT: Two elderly patients with leaking TAAs who were at high risk for surgical intervention were transferred to our institution for possible endovascular treatment. Both patients underwent successful endovascular exclusion of the leaking TAAs using multiple stacked AneuRx thoracic endoprostheses. One patient remains alive and well at 1 year with an excluded aneurysm; the other patient died from heart failure 2 months after endografting. CONCLUSIONS: While the early results of the endovascular exclusion of leaking TAAs are promising, the use of thoracic endoprostheses remains investigational.

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PubMed2002

Regression of a descending thoracoabdominal aortic dissection following staged deployment of thoracic and abdominal aortic endografts.

PURPOSE: To describe the successful endovascular repair and regression of an extensive descending thoracoabdominal aortic dissection associated with thoracic and abdominal aortic aneurysms. CASE REPORT: An 83-year-old man presented with acute chest pain and shortness of breath. A descending thoracoabdominal aortic dissection that extended from near the left subclavian artery (LSA) to the right common iliac artery was found on computed tomography. Separate aneurysms in the thoracic and abdominal aorta were also identified. Staged endovascular procedures were undertaken to (1) close the single entry site and exclude the aneurysm in the thoracic aorta with an AneuRx thoracic stent-graft, (2) exclude the abdominal aneurysm and distal re-entry site with a bifurcated AneuRx endograft, and (3) treat a newly dilated thoracic segment between the LSA and first thoracic stent-graft. At 1 year, the false lumen had completely disappeared, the thoracic aneurysm had collapsed onto the endograft, and the abdominal aneurysm had shrunk by 30%. CONCLUSIONS: The potential to treat extensive aortic dissections with the hope that they might regress is promising, but repair of highly complex lesions involving one or more aneurysms in addition to the dissection requires meticulous imaging studies both preoperatively and intraprocedurally.

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