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E Ascer

Publications and source records attributed to E Ascer.

At least 37 records · Page 2Linked to original sources
PubMed1992

Interleukin-1 and thromboxane release after skeletal muscle ischemia and reperfusion.

Interleukin-1 and thromboxane are known to mediate the host response to sepsis, trauma, and myocardial ischemia. A well-established model of canine isolated gracilis muscle was used to evaluate whether cytokine (interleukin-1) played a role in skeletal muscle ischemia-reperfusion injury. Six adult mongrel dogs (25-30 kg) were subjected to six hours of muscle ischemia followed by reperfusion. Gracilis venous samples were collected pre-ischemia and at one hour of reperfusion. Systemic (arterial) blood samples were taken at one hour of reperfusion. Sera were analyzed for interleukin-1 by bioassay and thromboxane (B2) by radio-immunoassay. The gracilis muscle of the operated limb was harvested in all the animals for assessment of the percentage of muscle necrosis. This was found to be 56.2 +/- 14.8% by serial transections, nitroblue tetrazolium staining, and computerized planimetry. Interleukin-1 levels in the gracilis venous effluent increased from 21.88 +/- 7.13 units/ml during pre-ischemic baseline to 50.42 +/- 9.12 units/ml after six hours of ischemia followed by one hour of reperfusion (p less than 0.04). Thromboxane B2 levels were 2983 +/- 1083 pg/ml and 9483 +/- 2218 pg/ml at pre-ischemia and at one hour of reperfusion respectively (p less than 0.04). Systemic levels of both interleukin-1 and thromboxane B2 at one hour of reperfusion were 0 units/ml and 1584 +/- 520 pg/ml respectively, which were significantly lower than the one hour reperfusion gracilis venous effluent levels (p less than 0.04). This is the first report in which cytokines have been implicated in skeletal muscle ischemia-reperfusion injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Intrathecal perfusion of an oxygenated perfluorocarbon prevents paraplegia after aortic occlusion.

A canine model was used to evaluate the effects of continuous intrathecal perfusion of an oxygenated perfluorocarbon emulsion on systemic and cerebral hemodynamics and neurologic outcome after 70 minutes of normothermic aortic occlusion. Twelve mongrel dogs were instrumented to monitor proximal and distal arterial blood pressure, cerebrospinal fluid pressure, spinal cord perfusion pressure, and somatosensory evoked potentials. The intrathecal perfusion apparatus consisted of two perfusing catheters, placed in the intrathecal space through a laminectomy, and a draining catheter percutaneously inserted in the cisterna cerebellomedullaris. The aorta was cross-clamped just distal to the left subclavian artery for 70 minutes. Animals were randomized into two groups: group 1 (n = 6) animals were treated with intrathecal perfusion of saline solution, whereas group 2 (n = 6) animals received oxygenated Fluosol-DA 20%. Data were acquired at baseline, during the cross-clamp period, and after reperfusion. Normothermic Fluosol or saline solution was infused at a rate of 15 mL/min beginning 15 minutes before cross-clamping and continued throughout the ischemic interval. There was no difference in proximal arterial blood pressure (97.2 versus 95.4 mm Hg; p > 0.05) or distal arterial blood pressure (14.6 versus 15.0; p > 0.05) between the two groups throughout the cross-clamp interval. Cerebrospinal fluid pressure rose significantly in both groups with the onset of intrathecal perfusion of either saline solution or Fluosol (7 +/- 1 versus 24 +/- 5 and 8 +/- 1 versus 40 +/- 4 mm Hg, respectively; p < 0.05). The rise in cerebrospinal fluid pressure was sustained throughout the perfusion interval in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Reduction of the extent of ischemic skeletal muscle necrosis by perfusion with oxygenated perfluorocarbon.

Oxygenated perfluorocarbon emulsion has been shown to preserve feline cerebral function after ischemia. The postulated protective effects of perfluorocarbons include improvement of blood rheology and prevention of neutrophil adherence by nonchemical inhibition of surface receptors. In this study, we used a well-described gracilis muscle model to investigate whether oxygenated perfluorocarbon can minimize skeletal muscle necrosis by mitigating the degree of leuko-sequestration. In eight adult mongrel dogs, both gracilis muscles were weighed and then subjected to 6 hours of normothermic ischemia followed by 48 hours of normothermic reperfusion. However, one randomly selected side (experimental side) was infused with oxygen (O2) Fluosol-DA 20% (4.4 +/- 0.2 mL O2/100 mL) intra-arterially at 12 mL/min for 40 minutes immediately after ischemia. Muscle biopsy specimens were obtained before ischemia and after 1 hour and 48 hours of reperfusion to estimate myeloperoxidase (MPO) activity, a marker of neutrophil infiltration. After 48 hours, both gracilis muscles were harvested and weighed in all animals. Muscle necrosis was measured by serial transections, nitroblue tetrazolium staining, and computerized planimetry. The transmuscular oxygen tension (pO2) of the gracilis muscle on the experimental side increased from 2 to 4 mm Hg during ischemia to 315 +/- 50 mm Hg during O2 Fluosol-DA 20% infusion. The percentage of muscle necrosis on the control side was 48.08% +/- 8.46%, compared with 27.62% +/- 6.96% on the experimental side (p less than 0.001). MPO activity was significantly higher at 48 hours of reperfusion compared with pre-ischemic and 1-hour reperfusion values (5.46 +/- 1.52 U/mg tissue protein versus 0.06 +/- 0.01 U/mg tissue protein and 0.16 +/- 0.06 U/mg tissue protein, respectively, in the control group; 1.78 +/- 0.60 U/mg tissue protein versus 0.16 +/- 0.08 U/mg tissue protein and 0.27 +/- 0.10 U/mg tissue protein, respectively, in the experimental group, p less than 0.05). However, MPO activity at 48 hours of reperfusion in the experimental group was significantly lower than in the control group (p less than 0.05). There was no difference in the percentage of weight gain between the control and the experimental groups (38.31% +/- 9.36% and 28.34% +/- 7.35%, respectively, p greater than 0.05). These data show that perfluorocarbons minimize the extent of skeletal muscle necrosis in this canine model. Based on our data on MPO activity, we believe t hat the protective effect of perfluorocarbons is in part due to th e decreased leuko-sequestration in the muscle during the the periods of ischemia and reperfusion.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

[Current approach in the treatment of isolated coronary arterial stenosis associated to arteriovenous coronary fistula].

Congenital coronary arteriovenous fistulae are commonly associated with complications which include congestive heart failure, bacterial endocarditis, angina pectoris, secondary to "coronary steal" phenomenon and fistula rupture. Conventional treatment of large coronary arteriovenous fistulae is surgical ligation. In this report we describe the data and therapeutic approach of a patient with a severe coronary stenosis in a large diagonal branch in whom PTCA was successfully conducted, while, in this opportunity no embolization of the fistula was performed.

Angioplasty, Balloon, Coronary↗
PubMed1992

[Directional atherectomy and coronary angioplasty: a therapy complementary to myocardial revascularization surgery].

A white male patient, 59 years old, with two prior surgical myocardial revascularization and unstable angina, was submitted to coronary arteriography that showed: all the saphenous vein grafts patent and obstruction of 75% in the saphenous vein graft to the second marginal branch of left circumflex artery. Left internal mammary artery (LIMA) was angiographically normal and 80% stenosis was detected in the distal segment of the left anterior descending coronary artery (LAD). The patient was submitted to directional coronary atherectomy for saphenous vein graft and coronary angioplasty for distal-LAD. Both procedures were successfully performed.

Angioplasty, Balloon, Coronary↗
PubMed1992

[Angioplasty in native coronary circulation in patients treated with myocardial revascularization].

PURPOSE: To evaluate the clinical results after angioplasty in the native coronary vessels in patients who had undergone previous coronary artery surgery. METHODS: From June 1987 to July 1990, 69 patients with previous coronary artery surgery underwent coronary angioplasty in the native arteries. Age ranged from 31 to 82 (mean = 57.5) years, fifty eight were males. Angina was present in all patients. The patients were classified in three groups according to the following criteria: group I--incomplete revascularization following bypass surgery (28 patients); group II--progression of the disease in ungrafted vessels (24 patients) and group III--progression of the disease in grafted vessels (17 patients). RESULTS: Primary success was achieved in 94% (65/69). Ninety-five percent in group I, 92% in group II and 94% in group III. Complications occurred in 4%; emergency surgery or deaths were not observed in this study. Forty patients (61%) repeated coronary arteriography an average follow-up of 4 months and restenosis was detected in 10 (25%); 8 of them were redilated. Survival rates was 95% and 75% of them were free of coronary events after an average follow-up of 13 months. CONCLUSION: Coronary angioplasty in these patients is a safe and effective interventional procedure in the treatment of coronary artery disease in native coronary vessels.

Adult↗
PubMed1992

[Coronary angioplasty in octogenarians].

PURPOSE: To evaluate the indications, results and follow-up of patients with 80 years old and over, who had undergone percutaneous transluminal coronary angioplasty (PTCA). METHODS: From July 1987 through July 1990, 36 patients, 80 years of age and over, had PTCA as an alternative method to treat coronary artery disease. Their age ranged from 80 to 85 (mean = 83) years. Twenty five were male. Significative obstruction was considered when 70% or more of the internal diameter was stenosed. Satisfactory results were achieved when reduction of 50% or more of the coronary artery obstruction was obtained. RESULTS: In 34 of 36 patients (94.4%), PTCA was successfully performed. Forty four of 46 coronary arteries were successfully dilated. One patient had acute coronary occlusion with acute myocardial infarction treated clinically. There were no emergency surgeries or early deaths. Clinical follow-up was obtained in 15 of the 34 patients. Four had repeated coronary arteriography (at 1, 3, 6 and 12 months after primary PTCA) due to angina. Two of them had restenosis and were successfully redilated (the patients restudied at 3 and 6 months, respectively). Within a mean clinical follow-up period of 9.6 (ranging from 1 from 21) months the following features were observed: two of 15 patients (13.3%) had acute myocardial infarction and were clinically followed; late death occurred in 3 patients (20%) with only one related to cardiac events. Survival has been observed in 12 of these 15 patients (80%). CONCLUSION: PTCA represents an alternative, safe and effective invasive procedure to treat octogenarians with coronary artery disease.

Aged↗
PubMed1992

The value and limitation of iloprost infusion in decreasing skeletal muscle necrosis.

Iloprost has been shown to minimize skeletal muscle necrosis when administered before the onset of ischemia in animal experiments, possibly by preventing neutrophil activation. Since patients with acute limb ischemia are seen after the process has begun, we investigated whether iloprost can be protective when given only during reperfusion. After anesthesia, 18 adult mongrel dogs underwent a standard isolated gracilis muscle preparation. In six control animals (group I) the gracilis muscle was subjected to 6 hours of ischemia followed by 48 hours of reperfusion. Group II animals (n = 6) received intravenous infusion of iloprost at a dose of 0.45 microgram/kg/hr beginning 1 hour before the onset of muscle ischemia and throughout the experiment (6 hours of ischemia and 1 hour of reperfusion). In addition to the continuous infusion, they received 0.45 microgram/kg intravenous boluses of iloprost 10 minutes before the induction of ischemia and 10 minutes before reperfusion. Group III animals (n = 6) had a similar ischemic interval, but were given a bolus of iloprost of 0.45 microgram/kg at end ischemia followed by continuous infusion of 0.45 microgram/kg/hr for 48 hours during reperfusion. Muscle biopsies were obtained at baseline and after 1 hour of reperfusion in all groups. Additional biopsies were obtained at 48 hours of reperfusion in groups I and III. Myeloperoxidase activity, a marker of neutrophil activation, was measured in all muscle biopsies. At the end of reperfusion, the gracilis muscle was harvested in all animals and weighed. Muscle necrosis was estimated by serial transection, nitroblue tetrazolium histochemical staining followed by computerized planimetry.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1992

[Anatomical limitations for the performance of angioplasty in coronary multivessel disease].

PURPOSE: To study anatomical limitation of coronary angioplasty, as alternative therapy in patients with multivessel disease and submitted to bypass surgery. METHODS: In 380 patients with multivessel disease and submitted to previous coronary bypass surgery, age ranged from 41 to 72 (average = 51) years, being 68% males. The following parameters were analyzed in the coronary arteriographies: anatomic aspects of the coronary arteries and distribution of the atherosclerotic stenosis. The patients were arranged in accordance to the criteria: complete revascularization, incomplete and no indication for coronary angioplasty. RESULTS: The patients were arranged in 3 different groups: I-80 (21%) patients included those in whom complete revascularization would be possible; II--55 (14.5%) patients in whom only incomplete revascularization but satisfactory would be possible and III--245 (65.5%) those patients in whom coronary angioplasty would no have indication. The data referind the patients of groups I and II were analyzed together--135 (35.5%) and arranged according to the number of arteries involved. It was observed: two vessel disease--71.8%, three vessel--18.6% and 4 or more vessel--9.6%. In group III it was observed 51.0% of the patients with 3 or more vessel disease. The major factors to contra indicate coronary angioplasty in group III included: chronic coronary obstruction 99 (40.4%); diffuse disease 11 (4.5%); technical difficulties 10 (4.1%); left main coronary artery obstruction 5 (2%) or when two or more causes were combined 120 (49%). CONCLUSIONS: Patients with multivessel disease and classic indication for coronary bypass surgery, have a basic limitation for angioplasty due to several anatomic factors. However, coronary angioplasty could be beneficial for a selected group of patients (35.5%) whenever a complete or incomplete revascularization could be obtained.

Adult↗
PubMed1991

Intracardiac and intrapulmonary Greenfield filters: a long-term follow-up.

The Greenfield vena caval filter has become the preferred method of vena caval filtration. Its high long-term patency rate and low complication rate make it ideal for those patients in whom anticoagulation has failed or is contraindicated. A known complication of filter insertion is the inadvertent placement or migration of the filter to the right side of the heart. We present three cases from our institution where the Greenfield filter was inadvertently ejected into the right atrium. An attempt at removal with a wire loop and sheath in two cases failed and resulted in the migration of one filter to the right inferior pulmonary artery. We found no evidence of long-term complications at 2, 45, and 60 months. We conclude that conservative management may be considered in these cases.

Adult↗
PubMed1991

A comparison of CO2 laser-assisted venous anastomoses and conventional suture techniques: patency, aneurysm formation, and histologic differences.

The expected patency and the potential complications of CO2 laser-welded end-to-end venous anastomoses have not been well established despite increasing clinical interest in the subject. To further study this relatively new technique we used the internal jugular veins (1.0 to 1.4 mm diameter) of 15 New Zealand White rabbits weighing 2.5 to 3.5 kg. On one randomly selected side, a laser-welded end-to-end anastomosis was performed in all animals by placing three equidistant stay sutures followed by welding the vein edges with a CO2 laser (spot size of 0.27 mm, power of 100 mW, and power density of 175 W/cm2). On the contralateral side, the vein was anastomosed with interrupted 10-0 nylon sutures in 10 animals, and in the remaining five animals a continuous 10-0 nylon suture technique was used. All anastomoses were surgically assessed at 30 days after operation. A significantly lower 30-day patency rate (p less than 0.05, Fisher's Exact Test) was found in anastomoses constructed by use of the continuous technique (20%) compared with either interrupted (90%) or the laser-assisted technique (87%). No significant difference was observed in 30-day patency between laser-assisted and conventional interrupted anastomoses. Anastomoses performed with the continuous and the laser-assisted technique required 12.5 +/- 1.3 and 12.9 +/- 3.0 minutes, respectively, whereas those constructed with interrupted technique required 19.1 +/- 4.5 minutes (p less than 0.05, Student-Neuman-Keuls' Test). No evidence of false or true aneurysm was noted in any of the animals. Histologic evaluation of laser-assisted anastomoses demonstrated early full-thickness coagulation necrosis of the wall with reendothelialization by 7 days and complete healing by 30 days after the procedure. Conventional anastomoses showed reendothelialization and minimal necrosis near the sutures at 7 days, but healing was complete by 30 days after the procedure. The patency rate of vein anastomoses performed with the CO2 laser is excellent and superior to the one obtained with continuous sutures, and except for less operating time, the former technique does not appear to offer any significant advantage over the conventional interrupted suture technique for small vein anastomosis in this animal model up to 1 month of follow-up.

Anastomosis, Surgical↗
PubMed1990

Improved strategies for secondary operations on infrainguinal arteries.

Secondary interventions play an important role in achieving the ultimate goal of limb salvage after primary infrainguinal interventions fail. By employing the described strategies and principles for secondary arterial reconstructions below the inguinal ligament, good results in terms of patency of the reoperated primary reconstruction or the secondary reconstruction can be obtained with significantly augmented limb salvage at a low cost in operative morbidity and mortality. These results mandate that vascular surgeons maintain an aggressive attitude toward the use of these secondary operations when a primary procedure fails to achieve or maintain its intended goal and a patient is faced with imminent limb loss because of distal ischemia.

Blood Vessel Prosthesis↗
PubMed1990

Influence of vein size (diameter) on infrapopliteal reversed vein graft patency.

We reviewed 239 infrapopliteal reversed greater saphenous vein graft bypasses placed for critical ischemia over a 7-year period to determine the influence of vein diameter on graft patency and limb salvage. Grafts were assigned to four groups based on the minimum external diameter measured during operation: less than 3.0 mm, n = 18; 3.0 mm, n = 59; 3.5 mm, n = 67; and greater than or equal to 4.0 mm, n = 145. A pattern of increasing graft patency and limb salvage among the four groups was noted as the minimum external diameter increased from less than 3.0 mm to greater than or equal to 4.0 mm. When compared to the larger grafts greater than or equal to 4.0 mm, primary graft patency was significantly lower both for less than 3.0 mm grafts (0% for less than 3.0 mm vs 65% for greater than or equal to 4.0 mm at 3 years, p less than 0.001) and for long (greater than 45 cm) 3.0 mm grafts (38% for long 3.0 mm vs 75% for greater than or equal to 4.0 mm at 2 years, p less than 0.005). All 3.5 mm and short (less than 45 cm) 3.0 mm grafts had patency rates similar to greater than or equal to 4.0 mm veins. Thus long 3.0 mm and all less than 3.0 mm reversed saphenous vein grafts should be considered at high risk for failure. Veins with fibrotic, thick-walled segments identified during operation (n = 19) had patency rates significantly lower than nonfibrotic veins (n = 270; p less than 0.01), and this may play a role in the failure of some less than 3.0 mm minimum external diameter vein grafts.

Arteriovenous Shunt, Surgical↗
PubMed1990

A modified method for management of prosthetic graft infections involving an anastomosis to the common femoral artery.

In the last 10 years we have treated 28 patients with 33 groin infections involving a common femoral artery anastomosis of prosthetic arterial grafts (2 aortic Dacron grafts, 31 peripheral polytetrafluoroethylene grafts). Management included complete graft preservation for patent infected grafts (11 cases), subtotal excision of occluded infected grafts leaving an oversewn 2 to 3 mm graft remnant attached to a patent artery critical for limb survival (16 cases), and total graft excision with arterial oversewing or ligation for anastomotic bleeding (6 cases). Essential treatment adjuncts included (1) radical operative wound debridement, and (2) secondary revascularization by means of bypasses tunneled via lateral uninfected routes, and unusual approaches to uninvolved patent outflow arteries (i.e., the distal superficial or deep femoral or popliteal arteries) after isolation of the infected wound. Follow-up averaged 3 years (1 to 10 years). This plan of treatment resulted in an 11% (3/28) hospital mortality and an amputation rate of 13% (4/30 threatened limbs). Of the 25 survivors with 30 infected groin grafts, 87% (26) of the wounds healed uneventfully by secondary intention within 1 to 8 weeks (mean, 4 weeks) and have remained healed. One infected groin wound did not heal and required delayed total graft excision. Three patients had late anastomotic disruption with hemorrhage at 8 months, 2 years, and 4 years after initial treatment. This selected use of complete or partial graft preservation and other essential treatment adjuncts are proposed as a safer, easier method for managing infected prosthetic arterial grafts in the groin.

Adult↗
PubMed1990

Remote distal arteriovenous fistula to improve infrapopliteal bypass patency.

The results of the use of prosthetic materials for femorocrural bypass surgery have been less than optimal. The creation of a distal anastomotic arteriovenous fistula to augment blood flow and velocity through the graft is well known. However, it may create turbulence at the anastomosis and steal blood flow away from the distal artery. A canine model was developed to evaluate the effect of fistula size on graft/arterial hemodynamics. In 16 patients we have constructed a distal arteriovenous fistula, which is remote from the distal anastomosis, and we studied the effect of such fistulas on bypass patency and distal arterial hemodynamics. Patients selected for this procedure had multiple previously failed reconstructions and limb-threatening ischemia and did not have usable autogenous vein. Femorotibial bypass graft reconstructions were performed with polytetrafluoroethylene followed by the creation of a side-to-side arteriovenous fistula 5 to 15 cm below the distal anastomosis in the same artery and accompanying veins. We have achieved a 1-year patency of 67% with a 75% limb salvage rate. We also serially measured blood flow and velocity within the bypass, the arteriovenous fistula, and the distal outflow vessel using duplex scanning after surgery. Mean estimated blood flow through the bypass during the immediate postoperative period was 264 ml/min, the arteriovenous fistula was 157 ml/min, and the distal artery was 19 ml/min. Unlike an arteriovenous fistula created at the distal anastomosis, a remote distal arteriovenous fistula not only increases graft blood flow but also augments native arterial blood flow between the distal anastomosis and fistula and thus may improve distal limb perfusion.

Animals↗
PubMed1990

Unsuspected inflow disease in candidates for axillofemoral bypass operations: a prospective study.

Routine arteriography of the axillary, subclavian, and innominate arteries before axillofemoral bypass surgery has not been advocated because of the presumed rarity of stenosis of these inflow vessels. However, we have noted in this patient population with extensive atherosclerosis that inflow disease can cause axillofemoral graft failure despite normal preoperative clinical and noninvasive parameters. We prospectively determined the incidence of unsuspected inflow stenosis with arteriography in 40 consecutive candidates for primary (28) or secondary (12) axillofemoral bypass surgery. A new arteriographic technique with a single translumbar puncture was developed to safely and clearly visualize the potential inflow and outflow tracts. Ten of the 40 patients (25%) exhibited inflow stenosis greater than 50% of luminal diameter (unilateral in eight patients and bilateral in two patients). Seven were on the left side (five subclavian, two axillary) and five were on the right side (three subclavian, one axillary, one innominate). In eight of the 40 patients (20%) the stenotic inflow lesion was ipsilateral to the ischemic leg and therefore proximal to the preferred inflow site of an axillofemoral bypass. Upper extremity arterial pressure measurements suggested potential inflow artery stenosis in only three of the 12 (25%) instances. These findings show that equal arterial pressures in the upper extremities do not ensure adequate inflow for an axillofemoral graft. Routine arteriographic assessment of inflow intacts is recommended before axillofemoral bypass surgery.

Adult↗