Biomedical subjects

Brian DeRubertis

Publications and source records attributed to Brian DeRubertis.

8 recordsLinked to original sources

PubMed2006

Analysis of outcomes following failed endovascular treatment of chronic limb ischemia.

Despite recent studies highlighting the advantages of endoluminal intervention in the management of chronic limb ischemia (CLI), outcomes following failed peripheral angioplasty remain less well described. We present a retrospective analysis of failed transluminal infrainguinal percutaneous arterial angioplasty with or without stenting (PTA/S) in patients with CLI. A database of patients undergoing infrainguinal PTA/S between 2002 and 2005 was maintained. Patients underwent duplex scanning follow-up at 2 weeks, 3 months, and every 6 months after the intervention. Angiograms were reviewed in all cases to assess lesion characteristics. Results were standardized to current Transatlantic Inter-Society Consensus (TASC) criteria. Kaplan-Meier survival analyses were performed to assess time-dependent outcomes. In total, our analysis involved 246 patients who underwent treatment for CLI using PTA/S. Eighteen percent of procedures (n = 46) were considered an intervention failure secondary to restenosis by duplex ultrasound, returning clinical symptoms, a nonhealing foot lesion, or the absence of a prior palpable pulse. Indications for the original procedure in patients whose PTA/S failed were tissue loss in 44%, claudication in 44%, and rest pain in 12%, while TASC lesion grades were A (0%), B (18%), C (18%), and D (64%). Of patients failing PTA/S, 4% failed in the first 30 days, 78% failed between 1 and 18 months, while 18% failed following 18 months, with a mean time to failure of 8.7 months. Also, 82% of PTA/S failures were candidates for a second endovascular procedure, 11% were suitable for only traditional open bypass, and 4% demonstrated progression of disease necessitating amputation. Of patients undergoing a second endovascular procedure, limb salvage rates were 86% at 12-month follow-up and there was a single periprocedural mortality and complication rate of 6.6%. Of patients requiring open surgical bypass after failed PTA/S, 20% (n = 1) required a major amputation and there were no mortalities. Failure of endoluminal therapy for treatment of lower extremity arterial occlusive disease is amenable to subsequent endovascular intervention for limb salvage with limited morbidity and mortality.

Adult↗

PubMed2006

Cerebral ischemia associated with PercuSurge balloon occlusion balloon during carotid stenting: Incidence and possible mechanisms.

BACKGROUND: Interruption of antegrade cerebral perfusion results in transient neurologic intolerance in some patients undergoing carotid angioplasty and stenting (CAS). This study sought to evaluate factors that contributed to the development of cerebral ischemia during PercuSurge balloon occlusion and techniques used to allow successful completion of the CAS procedure. METHODS: The PercuSurge occlusion balloon was used in 43 of 165 patients treated with CAS for high-grade stenosis (mean stenosis, 90%). All 43 patients were at increased risk for endarterectomy (7 restenosis, 3 irradiation, 3 contralateral occlusion, and 30 Goldman class II-III); 20% were symptomatic. Symptoms of cerebral hypoperfusion during temporary occlusion of the internal carotid artery occurred in 10 of 43 and included dysarthria (7/10), agitation (6/10), decreased level of consciousness (5/10), and focal hemispheric deficit (3/10). An incomplete circle of Willis or contralateral carotid artery occlusion, or both, was present in 8 of 10 patients. Symptoms resulting from PercuSurge balloon occlusion were managed by balloon deflation with or without evacuation of blood from the internal carotid artery using the Export catheter. All symptoms resolved completely without deficit after deflation of the occlusion balloon. RESULTS: The development of neurologic symptoms after initial PercuSurge balloon inflation and occluded internal carotid artery flow was associated with a decrease in the mean Glasgow Coma Scale (GCS) from 15 to 10 (range, 9 to 14); the GCS returned to normal after occlusion balloon deflation and remained normal during subsequent reinflation. The mean time to spontaneous recovery of full neurologic function was 8 minutes (range, 4 to 15 minutes). No thrombotic or embolic events were present on cerebral angiography or computed tomography scan. Balloon reinflation was performed after a mean reperfusion interval of 10 minutes after full neurologic recovery (range, 4 to 20 minutes). The mean subsequent procedure duration was 11.9 minutes (range, 6 to 21 minutes). No recurrence of neurologic symptoms occurred when the occlusion balloon was reinflated. All 10 patients underwent successful CAS without occlusion, dissection, cerebrovascular accident, or death. CONCLUSION: Several factors may contribute to the development of neurologic intolerance during CAS with balloon occlusion. Elucidation of the protective cellular mechanisms that invoke ischemic tolerance after the initial transient ischemic event may enable CAS with embolic protection in patients who cannot tolerate initial interruption of antegrade cerebral perfusion.

Aged↗

PubMed2006

The development of endotension is associated with increased transmission of pressure and serous components in porous expanded polytetrafluoroethylene stent-grafts: characterization using a canine model.

OBJECTIVE: This study used a canine model of abdominal aortic aneurysms (AAAs) to compare intra-aneurysmal pressure and thrombus formation after exclusion with Dacron and expanded polytetrafluoroethylene (ePTFE) stent-grafts. METHODS: Prosthetic AAAs with implanted strain-gauge pressure transducers were treated by stent-graft exclusion using Food and Drug Administration-approved devices in 10 mongrel dogs: five Dacron (AneuRx) and five ePTFE (original Excluder). Intra-aneurysmal pressure was measured over 4 weeks after AAA exclusion and indexed to the systemic pressure, represented as a percentage of a simultaneously obtained systemic pressure (value = 1.0). Magnetic resonance imaging (MRI) of the intra-aneurysmal thrombus was performed at 1, 2, and 4 weeks after exclusion and expressed as a signal-to-noise ratio (S:N) to control for background signal intensity. Comparisons of pressures and S:N between the two stent-grafts was analyzed with the Student's t test. Intra-aneurysmal thrombus was characterized histologically. RESULTS: In animals excluded with both Dacron and ePTFE stent-grafts, the intra-aneurysmal pressure was nonpulsatile and reduced to <30% of systemic pressure. Significantly greater pressure transmission was observed after AAA exclusion using ePTFE compared with Dacron stent grafts (systolic pressure: ePTFE, 0.28 +/- 0.12 vs Dacron, 0.11 +/- 0.02, P < .001; mean pressure: ePTFE, 0.16 +/- 0.08 vs Dacron, 0.06 +/- 0.02, P < .001). MRI confirmed the absence of perfusion in all aneurysms. The T1-weighted signal intensity remained persistently elevated (S:N at 1 week, 2.7 +/- 0.4 vs 2 weeks, 4.0 +/- 0.2 vs 4 weeks, 5.4 +/- 1.3) in ePTFE-treated intra-aneurysmal thrombus, suggesting an absence of thrombus organization. In contrast, progressive evolution of T1 signal intensity in aneurysms excluded by Dacron stent-grafts was consistent with maturation from intact red blood cells (S:N at 1 week, 3.3 +/- 0.4) to methemoglobin (S:N at 2 weeks, 6.1 +/- 0.8), and then hemosiderin and ferritin (S:N at 4 weeks, 2.4 +/- 0.5). Histologically, ePTFE-excluded aneurysms contained poorly organized thrombus with red blood cell fragments and haphazardly arranged fibrin deposition indicative of active remodeling and continued influx of transudated serum. In aneurysms excluded by Dacron stent-grafts, dense, mature collagenous connective tissue and organized fibrin were present, indicative of greater thrombus organization. CONCLUSIONS: Stent-graft treatment reduces intra-aneurysmal pressure to <30% of systemic pressure when no endoleak is present; however, significantly greater pressure is present in aneurysms treated with porous ePTFE stent-grafts than Dacron grafts. Histologic and MRI imaging analysis suggest that active transudation of serous blood components may be contributing to this increased intra-aneurysmal pressure.

Animals↗

PubMed2006

Evaluation of the accuracy of a wireless pressure sensor in a canine model of retrograde-collateral (type II) endoleak and correlation with histologic analysis.

BACKGROUND: The utility of intra-aneurysmal pressure determination is dependent on the ability to measure pressure in the presence of endoleak and thrombosis. In this study, the accuracy of a CardioMEMS wireless pressure sensor (CardioMEMS, Atlanta, Ga) transducer in the presence of thrombus associated with type II endoleak was measured. METHODS: Type II endoleaks were created in four mongrel dogs by implanting four collateral arterial side branches (lumbar and caudal mesenteric arteries) as a Carrel patch onto a 3-cm prosthetic polytetrafluoroethylene abdominal aortic aneurysm (AAA). The aneurysm was excluded 2 weeks later from antegrade perfusion by a stent graft. The wireless pressure sensor was positioned in the AAA external to the stent graft. A Konigsberg intraluminal solid-state strain-gauge pressure transducer (Konigsberg Instruments, Pasadena, Calif) that is accurate in the presence of thrombus served as the control to determine AAA pressure. Both of the transducers were implanted on the luminal surface of the aneurysm, 180 degrees opposite from the Carrel patch and endoleak channel. Intra-aneurysmal pressure resulting from the type II endoleak was measured twice daily for 4 weeks using both transducers. A total of 56 pre-exclusion and 224 post-exclusion distinct pressure determinations were made. Intra-aneurysmal pressure was indexed to the systemic pressure that was simultaneously measured by a strain-gauge pressure transducer implanted in the native aorta. Histologic analysis of the aneurysm contents was performed with hematoxylin and eosin. RESULTS: The intra-aneurysmal systolic, mean, and pulse pressures produced by the type II endoleak were significantly lower than systemic pressure in all animals and were < 60% of systemic pressure (P < .001). Close correlation between the wireless transducer and the control strain-gauge transducer was observed (R = 0.83, P < .001). Arteriography and Doppler ultrasound documented retrograde flow through the aneurysm side branches and persistent endoleak patency up to the time of euthanasia. Pathologic analysis demonstrated the endoleak channel to be patent and separated from the transducers by thrombus, which surrounded both transducers. CONCLUSIONS: Intra-aneurysmal pressure generated by type II endoleaks may be accurately measured through thrombus using a wireless pressure sensor in the canine model. The wireless sensor has the potential for clinical applicability in diagnosing and characterizing type II endoleaks.

Angioplasty↗

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↗

PubMedDate not supplied

Rupture of excluded popliteal artery aneurysm: implications for type II endoleaks--a case report.

The fate of popliteal artery aneurysms after ligation and bypass is believed to be relatively innocuous. The patient presented in this report, however, experienced spontaneous rupture of a popliteal aneurysm 11 years after ligation and bypass. Magnetic resonance angiography was used to establish the diagnosis of rupture, which was subsequently confirmed at surgery. Intraoperative arteriography demonstrated persistent collateral arterial perfusion of the excluded popliteal aneurysm sac. The collateral arterial flow originated from the superior and inferior lateral genicular arteries. The persistent arterial perfusion resulted in growth of the aneurysm from 4.2 to 7.0 cm over the 11-year period. The ruptured aneurysm was successfully treated by direct arterial exposure and suture ligation of the collateral vessels performed from within the aneurysm sac. The development of popliteal aneurysm expansion and rupture as a result of collateral arterial perfusion suggests that persistent collateral perfusion of abdominal aortic aneurysms after endovascular repair (type II endoleak) may lead to aneurysm rupture. Therefore, close observation and intervention for aneurysm expansion to prevent rupture of the excluded aneurysm are warranted.

Aged↗

PubMedDate not supplied

Current management of extracranial carotid artery disease.

Stroke is the third most common cause of death in the United States. There are approximately 700,000 strokes/year; 80% are ischemic, and 20-30% of ischemic strokes are secondary to carotid disease. Carotid stenosis is traditionally treated by carotid endarterectomy (CEA). Multicenter, randomized, controlled trials have shown that surgery significantly reduces the risk of ipsilateral stroke in patients with severe symptomatic and asymptomatic carotid stenosis. Endovascular techniques for treating carotid stenosis have been developed over recent years. Carotid angioplasty and stenting (CAS) with cerebral protection has become an alternative to CEA for high-surgical-risk patients and the procedure of choice for stenoses inaccessible by surgery. In this review we summarize the existing data regarding the traditional state of management of extracranial carotid artery stenosis and compare these data to a critical analysis of the recent results of CAS.

Angioplasty↗

PubMedDate not supplied

Experimental analysis of transvenous ultrasonography in localizing and grading renal artery stenosis.

This study evaluated the potential for transvenous ultrasonography to assess renal artery stenosis (RAS), the most common correctable cause of hypertension in the United States. We developed a porcine model for studying RAS using TVUS. An endovascular ultrasound probe was placed into the inferior vena cava and renal veins to image renal arteries in which stenoses had been surgically created in varied locations and to varied degrees. TVUS was then used to identify and assess these stenotic lesions. The accuracy of TVUS for determining the degree and location of the stenoses was then determined using contrast arteriography as the standard. When compared with arteriography, TVUS identified and properly located all six lesions and correctly quantified the degree of stenosis in five of the six lesions. TVUS is an effective means of assessing the presence, degree, and location of stenotic lesions of the renal arteries in this animal model. Study of this method in humans may be warranted.

Animals↗