Biomedical subjects

Jason Rhee

Publications and source records attributed to Jason Rhee.

4 recordsLinked to original sources

PubMed2005

Analysis of anatomic factors and age in patients undergoing carotid angioplasty and stenting.

Recent data suggest that patient age >80 years may be associated with increased risk of periprocedural complications from carotid angioplasty and stenting (CAS). In this study, we analyzed anatomic risk factors in patients undergoing CAS based on age >80 or <80 years. Our hypothesis was that patients >80 would have more challenging anatomy. Between February 2003 and August 2004, 82 patients underwent CAS. Images for 57 lesions were available for review. Eighteen patients were > or =80 years old and 39 were <80. Cerebral protection devices, including EPI Filterwire, Percusurge, Accunet, and Angioguard, were used in all but two cases; and self-expanding stents (Wallstent, NexStent, Acculink, Precise) were placed in all. Arterial anatomic characteristics were assigned a score based on complexity and associated procedural risk. Characteristics evaluated using angiographic images were aortic arch elongation classification, arch calcification, common carotid/innominate stenosis, common carotid tortuosity, internal carotid tortuosity, index lesion length, index lesion calcification, and index lesion stenosis. Statistical analysis was performed using Fisher's exact test. CAS was successfully completed in 98% of cases. The two patients in whom we could not perform CAS were 79 and 83 years old. The anatomic characteristics that were statistically significantly more complex/severe in patients > or =80 were arch calcification (p = 0.045), common carotid/innominate stenosis (p = 0.023), common carotid tortuosity (p = 0.049), and internal carotid tortuosity (p = 0.032). There was no statistically significant difference in arch elongation classification, lesion length, lesion calcification, or stenosis severity (p = nonsignificant). Overall, patients > or =80 years had an increased incidence of complex anatomic risk factors compared to younger patients (p < 0.001). Cerebrovascular accident without residual deficits occurred in two patients; both were >80 years old. Complex arterial anatomy is more often present in patients >80 years and may explain the increased complication rates associated with CAS. Pre- or intraoperative consideration of these characteristics may help provide better risk assessment in candidates for CAS.

Age Factors↗

PubMed2005

Comparison of results in endovascular interventions for infrainguinal lesions: claudication versus critical limb ischemia.

This study analyzed clinical success, patency, and limb salvage after endovascular repair in patients treated for chronic limb ischemia presenting with claudication versus critical limb ischemia. Between October 2001 and August 2004, 115 patients (mean age 71) underwent endovascular treatment for infrainguinal arterial disease. Techniques included subintimal angioplasty and transluminal angioplasty with or without stents. Lesions were classified according to Transatlantic InterSociety Consensus. Follow-up (mean 11 months) included physical exam, ankle-brachial index, and duplex ultrasound. Patency rates were determined using Kaplan-Meier and compared by log-rank analysis. One hundred ninety-nine lesions were treated in 121 limbs using percutaneous techniques. Comorbidities were similar except higher rates of diabetes mellitus (67% vs 41%, P < 0.001) and chronic renal insufficiency (22% vs 7%, P < 0.05) were found in critical limb ischemia patients. Primary patency for claudicants was 100 per cent, 98 per cent, and 85 per cent at 3, 6, and 12 months and 89 per cent, 80 per cent, and 72 per cent for critical limb ischemia, respectively (P = 0.06). Limb salvage was 91 per cent at 12 months for critical limb ischemia patients. Morbidity was similar between groups, and there was no perioperative mortality. Percutaneous intervention for both claudication and critical limb ischemia provides acceptable 12 month patency with limited morbidity.

Adult↗

PubMed2004

Computer simulation as a component of catheter-based training.

INTRODUCTION: Computer simulation has been used in a variety of training programs, ranging from airline piloting to general surgery. In this study we evaluate the use of simulation to train novice and advanced interventionalists in catheter-based techniques. METHODS: Twenty-one physicians underwent evaluation in a simulator training program that involved placement of a carotid stent. Five participants were highly experienced in catheter-based techniques (>300 percutaneous cases), including carotid angioplasty and stenting (CAS); the remaining 16 participants were interventional novices (<5 percutaneous cases). The Procedicus VIST simulator, composed of real-time vascular imaging simulation software and a tactile interface coupled to angiographic catheters and guide wires, was used. After didactic instruction regarding CAS and use of the simulator, each participant performed a simulated CAS procedure. The participant's performance was supervised and evaluated by an expert interventionalist on the basis of 50 specific procedural steps with a maximal score of 100. Specific techniques of guide wire and catheter manipulation were subjectively assessed on a scale of 0 to 5 points based on ability. After evaluation of the initial simulated CAS procedure, each participant received a minimum of 2 hours of individualized training by the expert interventionalist, with the VIST simulator. Each participant then performed a second simulated CAS procedure, which was graded with the same scale. After completion, participants assessed the training program and its utility via survey questionnaire. RESULTS: The average simulated score for novice participants after the training program improved significantly from 17.8 +/- 15.6 to 69.8 +/- 9.8 (P < .01), time to complete simulation decreased from 44 +/- 10 minutes to 30 +/- 8 minutes (P < .01), and fluoroscopy time decreased from 31 +/- 7 minutes to 23 +/- 7 minutes ( P < .01). No statistically significant difference in score, total time, or fluoroscopy time was noted for experienced interventionalists. Improvement was noted in guide wire and catheter manipulation skills in novices. Analysis of survey data from experienced interventionalists indicated that the simulated clinical scenarios were realistic and that the simulator could be a valuable tool if clinical and tactile feedback were improved. Novices also thought the simulated training was a valuable experience, and desired further training time. CONCLUSIONS: An endovascular training program using the Procedicus VIST haptic simulator resulted in significant improvement in trainee facility with catheter-based techniques in a simulated clinical setting. Novice participants derived the greatest benefit from simulator training in a mentored program, whereas experienced interventionalists did not seem to derive significant benefit.

Blood Vessel Prosthesis Implantation↗

PubMed2004

Stent graft treatment for abdominal aortic aneurysm repair: recent developments in therapy.

PURPOSE OF REVIEW: Minimally invasive endovascular techniques for the treatment of abdominal aortic aneurysms have significantly reduced the morbidity of these procedures compared with standard surgical repair. In addition, patients with extensive comorbid medical illnesses in whom standard operative repair is contraindicated may be successfully treated using endovascular means. RECENT FINDINGS: Recently, several important developments have significantly advanced this area of treatment. The Food and Drug Administration has approved four endovascular stent grafts for the treatment of abdominal aortic aneurysms: the Medtronic AneuRx, the W.L. Gore Excluder, the Cook Zenith, and the Guidant Ancure. The Zenith received approval for marketing in 2003 and has gained relatively wide use, in part because of its ability to treat aneurysms with relatively large-diameter implantations zones. Also in 2003, Guidant Corporation withdrew the Ancure graft from marketing and distribution. The withdrawal was influenced by difficulties encountered using the graft's delivery system and improper reporting to the Food and Drug Administration. Enrollment has also been recently completed for the phase II Food and Drug Administration trials of the Medtronic Talent graft and the Cordis Fortron graft. These devices have been approved for use in the European Union and are awaiting Food and Drug Administration panel meeting in the United States. Several significant advances have also occurred recently in stent graft research and development. Of particular significance has been the initiation of the phase I trial of the Trivascular Enovus graft. Deployment of the Trivascular graft may be accomplished through a delivery system that is considerably reduced in profile. The potential for percutaneous application of the graft may be available in the future. In selecting the specific stent graft to be used for endovascular abdominal aortic aneurysm repair, the specific graft characteristics must be considered, particularly with regard to the individual patient's anatomic and physiologic characteristics. Comparative analysis of the several of the various stent grafts has been performed. Results have varied with regard to the need for secondary interventions, aneurysm sac size reduction, and the occurrence of continued perfusion of the aneurysm sac. In addition, the indications for use of endovascular grafts compared with standard open surgery have not yet been fully defined. SUMMARY: This article describes the general principles of use for endovascular devices for the repair of abdominal aortic aneurysms. It details the features and results for the devices in current use, and highlights the recent developments in stent graft treatment of abdominal aortic aneurysms.

Aortic Aneurysm, Abdominal↗