Biomedical subjects

P L Wyffels

Publications and source records attributed to P L Wyffels.

9 recordsLinked to original sources

PubMed2000

Assessment of a polyester-covered nitinol stent in an atherosclerotic swine model.

PURPOSE: To evaluate the short-term patency and healing characteristics of the Cragg EndoPro covered stent in an atherosclerotic model as one of the Food and Drug Administration requirements before possible approval of the device for human use in the United States. MATERIALS AND METHODS: Seventeen self-expanding stent-grafts were placed in the aorta and right and left iliac arteries of six Yucatan microswine exposed to a regimen of accelerated atherosclerosis. The stent-grafts were constructed from nitinol wire formed into a tubular zigzag configuration. The stent frame was covered by a thin woven polyester fabric tube, with medium permeability, available in multiple diameters and lengths. The animals were killed at 24 hours, 3 months, and 6 months. Assessment was done by angiography and histology. RESULTS: All stents were patent immediately after deployment. Two stents were occluded at follow-up, indicating an 88% patency rate. Minor lumen narrowing was found at the follow-up intervals. Histologic examination revealed a mixture of mature and immature endothelial cells lining both the native and stented regions in all vessels examined. The new endoluminal surface was composed primarily of fibrocollagen and elastic fibers and smooth muscle cells. Intimal thickness was inversely correlated to medial thickness. Medial compression with atrophy was observed routinely with rare necrosis. Complete tissue ingrowth was seen by 3 months. The degree of vascular inflammation increased over time, as well as the foreign body giant cell reaction to the polyester fabric. CONCLUSION: The patency rate does not appear to be better than that with angioplasty or noncovered stent placement in the studied time frame. The progressive vascular inflammatory changes noted should be further investigated in longer-term animal trials to ensure its safety in humans because this device is meant to be permanent.

Alloys↗

PubMed2000

Pharmacomechanical thrombolysis with use of the brush catheter in canine thrombosed femoropopliteal arterial PTFE bypass grafts.

PURPOSE: To assess the efficacy, acute endothelial changes, and distal arterial emboli after use of the Cragg thrombolytic brush catheter in mature thrombosed polytetrafluoroethylene (PTFE) femoropopliteal arterial grafts in canines. MATERIALS AND METHODS: PTFE femoropopliteal arterial grafts were implanted in 10 canines and were allowed to mature for approximately 4 weeks. The grafts were thrombosed by mechanical means and allowed to remain thrombosed for 24-72 hours. Through a left carotid cut-down, standard Seldinger arterial puncture was performed, followed by catheterization of the thrombosed graft. A soft, low-speed, brush (6 mm in diameter) aided by preprocedure pulse-spray urokinase infusion was utilized for thrombolysis. The native vessels, just proximal and distal to the anastomosis, were evaluated microscopically for endothelial damage. Arteriography was used for assessment of distal embolus. RESULTS: All grafts were successfully thrombosed before thrombolysis. One graft could not be traversed with a wire and catheter and was, therefore, not treated. Immediate preprocedure pulse-spray urokinase infusion in the remaining nine grafts did not reconstitute antegrade flow in any instance and left significant amounts of residual thrombus in all treated grafts. Mechanical brush thrombolysis reconstituted antegrade flow in all nine treated grafts and complete graft thrombolysis was obtained in most. This was accomplished in a mean time of less than 4 minutes. Emboli were noted angiographically in 67% of cases. Histologic studies showed vessel wall damage limited to the intima or media in 67% of anastomoses. CONCLUSION: This method offers a simple and rapid means of recanalizing thrombosed PTFE femoropopliteal arterial grafts in the studied model. This technique provides a means of rapidly "debulking" most intragraft thrombi. This may result in a shorter course of thrombolytic infusion. Potential benefits may include shortening the total treatment time and decreasing morbidity and cost associated with percutaneous thrombolysis. The occurrence of distal emboli in a majority of cases is a concerning limitation of this technique.

Animals↗

PubMed1993

The advantages of early operation with splenorrhaphy versus nonoperative management for the blunt splenic trauma patient.

The importance of splenic preservation in reducing the risk of overwhelming post-splenectomy sepsis as well as the heightened awareness of transfusion-related infections have led to changing concepts in the management of blunt splenic trauma. A 10-year retrospective review (1980-1989) of blunt splenic trauma at a Level I trauma center is presented. One hundred eighty five blunt splenic injuries were treated, with a mortality rate of 7 per cent. Splenorrhaphy was performed in 7 per cent of patients in the first 5-year period (48% underwent splenectomy, and 45% were managed nonoperatively). The rate of splenorrhaphy increased to 22 per cent during the second 5-year period, with a subsequent decrease in both splenectomy (39%) and nonoperative management (39%). During the last year of review, 65 per cent of bluntly injured spleens were able to be salvaged (35% managed by splenorrhaphy and 30% by observation). Blood usage averaged 1.1 units/patient in the nonoperative group, 3.3 units/patient in the splenorrhaphy group, and 7.9 units/patient in those undergoing splenectomy. Nonoperative management of blunt splenic trauma can clearly be successful. However, patients chosen for this method should be completely hemodynamically stable to avoid requiring blood transfusions. A combination of early operation and splenorrhaphy with the use of autotransfusion devices, remains a better alternative in the less stable patient with multiple injuries. This method provides for a high rate of splenic salvage while decreasing the need for homologous blood transfusions.

Adult↗

PubMed1992

Increased limb salvage with intraoperative and postoperative ankle level urokinase infusion in acute lower extremity ischemia.

Over a 30-month period (May 1988 to November 1990) 143 acutely ischemic lower extremities (126 patients) were treated with an aggressive surgical approach that included ankle level tibial-peroneal artery thromboembolectomy. Twelve lower extremities in 10 patients that remained ischemic were further treated with adjuvant ankle level urokinase infusion. Sixteen ankle level arteries in 12 extremities were infused with an intraoperative bolus (1 to 2) of urokinase (50,000 to 100,000 units). Continuous postoperative urokinase (25,000 to 50,000 units per catheter per hour x 1 to 5 days) was infused through ankle level arteriotomies in 10 extremities (14 arteries) that did not improve with the initial intraoperative bolus. Concomitant bypass grafting was necessary in four extremities. With adequate inflow established, adjuvant ankle level urokinase salvaged all 12 extremities. The mean increase in ankle/brachial pressure index was 0.84. During continuous postoperative urokinase infusion, lower extremity bleeding requiring blood transfusion occurred in four patients (50%). No deaths occurred in the operative period. Although rhabdomyolysis occurred in 90% of patients, no patients had renal insufficiency. The addition of ankle level urokinase delivery increased the potential limb salvage from 90% of the entire 143 extremities treated during this period to an actual limb salvage of 98%. A mean follow up of 13 months (6 to 36 months) identified one late amputation. Despite the demanding postoperative management required in these patients and the frequent need for early reoperation, the limb salvage obtained justifies this aggressive adjuvant technique in the management of the acutely ischemic lower extremity.

Aged↗

PubMed1991

Carotid endarterectomy in a community hospital surgical practice.

Three hundred twenty-four carotid endarterectomies (CEAs) were performed on 303 patients over 5 years. Sixty per cent of the patients were symptomatic with completed stroke (36.4%), amaurosis fugax (35.4%) or transient ischemic attack (TIA) (50.5%). Some patients had multiple symptoms. Perioperative stroke occurred in four patients (1.2%) and 30-day mortality in five (1.5%). The combined stroke-mortality rate was 2.8 per cent. Other postoperative complications included TIA (1.9%), cranial nerve injury (3.1%), wound hematoma (6.5%), and hypertensive reperfusion syndrome (9.6%). Ten early reoperations were performed for wound hematoma (7) or technical problems (3). Follow-up of 284 CEAs (88%) at a means of 31 months revealed 33 late deaths, with two due to stroke. Late strokes occurred in 11 patients (3.9%). Five late strokes were ipsilateral (1.8%) and six were contralateral (2.1%) to the operated carotid artery. Ninety-seven carotid arteries were evaluated by duplex ultrasound scanning at a mean postoperative interval of 27.2 months. Ninety-two per cent had 0-30 per cent restenosis, 5 per cent had 40 per cent to 60 per cent restenosis and 3 per cent had 70 per cent or greater restenosis. The authors conclude that CEA can be performed with acceptable morbidity and mortality rates and that it is a durable operation that reduces the risk of late stroke.

Adult↗

PubMed1990

Increased limb salvage. Distal tibial/peroneal artery thrombectomy/embolectomy in acute lower extremity ischemia.

Fifty-five acutely ischemic lower extremities, in 35 patients, which remained ischemic after standard thrombectomy/embolectomy techniques were further treated with distal tibial/peroneal thrombectomy/embolectomy by ankle level arteriotomy to increase limb salvage. A total of 84 infrapopliteal arteries were explored and thromboembolectomy performed in 79. The precipitating ischemic event was arterial embolus in 38 per cent, arterial thrombus in 60 per cent, and trauma in 2 per cent of the cases. There were 16 female and 19 male patients. Additional bypass grafting was used in 18 per cent of extremities. The limb salvage rate was 91 per cent in this select "tibial/peroneal" group. This technique salvaged 50 limbs that otherwise would have required major amputation. The addition of this technique changed the potential limb salvage rate from 76 per cent of the entire 199 lower extremities treated during this period to an actual limb salvage rate of 97 per cent. Operative mortality was 16 per cent in this selected group with an overall mortality of 6 per cent for all patients with acutely ischemic lower limbs. A mean patient follow-up of 32 months (range 12 to 72 months) identified only three late amputations, demonstrating that distal tibial/peroneal thrombectomy/embolectomy is a durable procedure. It is a technically easy means of promoting limb salvage in the acutely ischemic limb which either 1) remains ischemic after standard transinguinal iliofemoral thromboembolectomy, or 2) is secondary to infrapopliteal artery occlusion. It allows successful thromboembolectomy of acutely occluded infrapopliteal arteries without distal popliteal arteriotomy. These techniques should be within the armamentarium of all surgeons dealing with acute lower extremity ischemia.

Adult↗

PubMed1984

Primary repair of bilateral diaphragmatic rupture with crural involvement.

A second case of bilateral hemidiaphragmatic rupture with involvement of the esophageal hiatus has been presented. Successful primary repair was accomplished by a transabdominal approach. Blunt diaphragmatic rupture, along with its presentation, diagnosis, and management, are discussed. The first priorities are life-threatening injuries and hemorrhage. Tears of the diaphragm should be considered in all patients with blunt abdominal and thoracic trauma, and when laparotomy or thoracotomy is performed, tears should be searched for visually. With discovery of injury to one hemidiaphragm, injury to the opposite side should be excluded. When identified, bilateral tears should be repaired primarily.

Adolescent↗

PubMed1983

A prospective study comparing nuclear scintigraphy and computerized axial tomography in the initial evaluation of the trauma patient.

Eighty-five consecutive patients admitted for trauma evaluation and fulfilling criteria suggesting the possibility of intra-abdominal injury underwent both immediate computerized axial tomography of the abdomen and a nuclear medicine evaluation, including a liver-spleen scan with or without a renal scan, in order to delineate their injuries and direct management. The limitations, advantages, and complementary use of each modality in the initial evaluation of the trauma patient is described. Overall, nuclear scintigraphy excelled in instances of contusion, in the evaluation of the restless or uncooperative patient, and in children. With computerized tomography, the retroperitoneal structures were well defined and multiple abdominal injuries could be seen. Neither modality demonstrated the presence of intra-abdominal fluid consistently. No patient with assumed isolated liver, spleen, or renal injury on the basis of the above studies, who was managed nonoperatively, required subsequent laparotomy.

Abdominal Injuries↗

PubMedDate not supplied

New thrombolytic brush catheter in thrombosed polytetrafluoroethylene dialysis grafts: preclinical animal study.

PURPOSE: To assess the safety, efficacy, endothelial changes, and risks of pulmonary embolic events after the use of a new thrombolytic brush catheter in mature thrombosed polytetrafluoroethylene (PTFE) dialysis grafts in an animal model. MATERIALS AND METHODS: Loop configuration PTFE grafts were implanted in the femoral vessels of 12 canines 4 weeks before mechanical thrombosis was performed. The thrombus was allowed to consolidate for 24 hours in 10 animals, 72 hours in one animal, and 7 days in one animal. Standard percutaneous criss-cross catheter access was performed, and a soft, low-speed, brush (6 mm in diameter), aided by 250,000 U of periprocedural urokinase, was utilized for thrombolysis. The native vessels, just distal to the anastomosis, and lungs were evaluated macro- and microscopically. RESULTS: Thrombolysis was complete in all grafts with the exception of a small segment between the crossing of the access vascular sheaths. The total thrombolysis time ranged from 8 to 12 minutes; this included 5 minutes of pulse-spray lacing. No difference in thrombolysis time was found with regard to the age or amount of thrombus. Minimal endothelial changes were noted and no evidence of acute pulmonary embolus was found on necropsy or histologic studies. CONCLUSION: This method offers a simple, safe, and efficient means of recanalization of thrombosed PTFE dialysis grafts in this canine model.

Animals↗