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Biomedical subjects

I M Ibrahim

Publications and source records attributed to I M Ibrahim.

At least 37 records · Page 2Linked to original sources
PubMed1990

Everted cervical vein for carotid patch angioplasty.

Because of the theoretic benefits of autologous vein we undertook an investigation to evaluate cervical veins (facial, external jugular) as patch material after carotid endarterectomy. A device that stimulated both circumferential fixation by sutures and radial tension exerted on in vivo patches was constructed to measure burst strength of tissue. Mean bursting pressure for groin saphenous vein (n = 10) was 94.5 +/- 15.1 pounds per square inch (psi), 75.5 +/- 8.9 psi for ankle saphenous vein (n = 10), 83.3 +/- 14.5 psi for everted (double layer) cervical vein (n = 5) and 10 +/- 3.3 psi for single layer cervical vein (n = 5). No significant differences between saphenous vein at any level and everted (double layer) cervical vein, but all were significantly different from single layer cervical vein (p less than 0.05). From June 1987 through November 1989, 19 patients underwent 21 carotid endarterectomies complemented with adjunctive everted cervical vein patch angioplasty. Indications for surgery were asymptomatic stenosis (53%), transient ischemic attack (29%), and cerebrovascular accident with recovery (18%). All patients were studied after surgery with duplex scanning. Asymptomatic recurrent stenosis was observed in one patient. Transient hypoglossal nerve dysfunction occurred in one other patient. One postoperative death occurred as a result of massive aspiration. These results indicate that everted cervical vein is comparable to the saphenous vein in resistance to bursting and can yield similar results as patch material after carotid endarterectomy. Accordingly, saphenous vein can be spared and lower extremity incisions avoided.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Primary aortoduodenal fistula. Diagnosis by computed tomography.

A primary fistula between the abdominal aorta and the duodenum is rare and usually fatal. Computed tomography in a symptomatic but stable patient enabled preoperative evaluation and even diagnosis of abnormal communications, real or incipient, between the vascular and enteric system. This case demonstrated the effectiveness, ease, and low cost of documenting a primary aortoduodenal fistula. Surgical results were ultimately improved by initiating early intervention and aggressive management. Therapeutic principles included early intervention with aneurysmectomy, duodenorrhaphy, and extra-anatomic bypass. Anatomic graft placement may be acceptable in selected cases.

Aorta, Abdominal↗
PubMed1989

Synchronous intrauterine and ectopic pregnancy associated with clomiphene citrate.

Although synchronous intrauterine and ectopic pregnancies associated with the use of clomiphene citrate for infertility are rare, the actual incidence might, in fact, be considerably higher than previously thought. The cornerstone for ruling out an extrauterine gestation is the presence of sonographic evidence of an intrauterine pregnancy, as the possibility of concomitant intrauterine and extrauterine gestation is perceived to be statistically rare. This has resulted in an unacceptably high incidence of negative ultrasound interpretations. During a recent 12 month period, four women treated with clomiphene citrate for infertility were diagnosed as having concomitant intrauterine and ectopic pregnancies. Three had pelvic sonograms that were erroneous for the extrauterine component. However, successful evacuation of the products of ectopic gestation was performed in each, despite an immediate preoperative false-negative ultrasound report. Three of the women delivered healthy normal infants at full term, and the fourth woman spontaneously aborted the products of the concomitant intrauterine gestation. All four did well postoperatively, and no gross complications were encountered. Reassessment of ultrasound diagnostic criteria and the use of more sensitive methods, such as endovaginal ultrasound in high risk patients, are indicated for any symptomatic patient using clomiphene citrate for infertility. Awareness of the prevalence of this entity and the limitations of ultrasound will lead to prompt intervention and improved survival rates.

Clomiphene↗
PubMed1989

Influence of dietary mineral imbalance on the incidence of urolithiasis in Egyptian calves.

The influence of certain dietary elements on the urolithiasis syndrome in cattle calves was elucidated. Calcium, phosphorus, and magnesium measurements were conducted on feed rations as well as on serum and urine samples collected from affected and normal calves. Analysis of the rations given to the animals showed phosphorus at higher levels than calcium, indicating mineral imbalance. Serum and urine of urolithic calves were characterised by high phosphorus, calcium, magnesium, urea, and creatinine levels. Physical examination of urine of affected animals showed a high degree of turbidity, a large amount of calcium carbonate, and triple phosphate as well as abundant amount of pus cells and red blood cells. The characteristic clinical symptoms of urine retention were observed. Moreover, some animals were found to urinate through an opening in front of the scrotal region.

Animal Feed↗
PubMed1986

Primary and adjunctive intra-arterial digital subtraction arteriography of the lower extremities.

Standard contrast arteriography (SCA) and intra-arterial digital subtraction arteriography (DSA) were performed during a 26-month period in 459 cases. The DSA group consisted of 22 aortoiliac studies, 66 crural-pedal arch studies, and 227 combinations. In addition, postoperative DSA was performed in 42 patients to evaluate graft patency, morphology, and inflow and runoff circulations. There were no significant differences in the quality of the preoperative aortoiliac studies performed by either SCA or DSA although, in select cases, one or the other of these techniques resulted in a superior study. Distal crural-pedal arch visualization was enhanced with DSA compared with SCA (85% vs. 65%) but when both were compared with their corresponding intraoperative completion arteriograms, the interpretive error rates resulted in comparable accuracies, false positive and negative rates, and predictive values. The likelihood of achieving graft patency in patients who have unsatisfactory preoperative visualization of the distal circulation by DSA is reasonable (11 of 27 patients) but inferior to the number obtained when there is adequate DSA visualization (40 of 53 patients). We conclude that DSA is a valuable adjunct to preoperative SCA but should not be used as the sole criterion for the assessment of operability for limb salvage. Intraoperative prereconstruction arteriography or direct surgical exploration of the crural arteries in patients with inadequate preoperative visualization will result in graft patency in a significant percentage of cases. Intra-arterial DSA for postoperative evaluation of lower limb bypass adds another dimension to analysis of graft structure and status of the host circulatory beds and also provides a method for accurate interpretation of postoperative data.

Angiography↗
PubMed1985

Omental protection of autogenous arterial reconstruction following femoral prosthetic graft infection.

Vascular graft infections in the femoral region that require synchronous revascularization are generally reconstructed with prosthetic grafts via extra-anatomic routes. If in situ revascularization is required, then autologous tissue provides optimal results. A particular challenge in this circumstance is achieving soft tissue coverage of the reconstruction where wide and radical débridement has removed the tissues ordinarily used for this purpose. If muscle flaps are not available or possible, the use of omentum is advocated. The omentum can be easily reached from behind the inguinal ligament and transposed on its bipedicled vascular base for coverage of vital structures in the femoral triangle, thereby obliterating dead space and providing a surface for both temporary and permanent skin coverage. The procedure is quite simple, can be performed rapidly, and should be considered for use in the dire situation that requires soft tissue coverage of exposed vessels in extraperitoneal locations.

Blood Vessel Prosthesis↗
PubMed1985

Adventitial cystic disease of the popliteal artery: failure of percutaneous transluminal angioplasty as a therapeutic modality.

Adventitial cystic disease of the popliteal artery is an important cause of peripheral vascular insufficiency in the young and middle-aged man. The pathologic feature is a mucinous cyst located within the adventitia of the artery that expands and secondarily compromises the vessel lumen. Although physiologically quite different, this process is easily mistaken for arteriosclerosis. The clinical history of sudden claudication in a young nonsmoking man, combined with characteristic angiographic features, are important clues to the correct underlying pathology. Treatment generally consists of cyst evacuation or local bypass. This article was prompted by the failure of percutaneous transluminal angioplasty to achieve durable success in controlling this unique type of arterial disease. Subsequent surgical intervention proved satisfactory, lending support to this modality as the treatment of choice.

Angioplasty, Balloon↗
PubMed1984

Improved patient selection for enzymatic lysis of peripheral arterial and graft occlusions.

Intraarterial thrombolysis by remote intravenous or direct intraarterial infusion of streptokinase is possible. The latter may be more effective with a lesser potential for systemic hemorrhagic complications because of the smaller dose administered directly in the area. Fifty patients with prosthetic graft, embolic, and renal artery occlusions were evaluated. Embolic occlusion responded dramatically, particularly since lytic therapy was initiated at an early stage. Patients with severe ischemia or those with simple localized occlusion were best treated by surgical means. Successful thrombolysis was also obtained with renal artery occlusions combined with percutaneous transluminal angioplasty. The management of patients with prosthetic graft occlusion by lytic therapy is complex. Optimal results can be obtained in patients presenting with occluded grafts after the immediate postoperative period and in those in whom previous satisfactory runoff has been demonstrated. Failure of lysis in this group is associated with a high incidence of limb loss due to unreconstructable obliterative disease. Successful lysis of occluded prosthetic grafts will often require corrective angioplasty or surgical revision.

Adult↗
PubMed1984

Biodegradation and aneurysm formation in umbilical vein grafts. Observations and a realistic strategy.

In a series of 756 glutaraldehyde-stabilized umbilical vein grafts implanted over a 7 1/2-year period, aneurysms were identified in seven cases. The earliest aneurysm was seen at 31 months after implantation and the remainder between 43 and 79 months after surgery. Corrective surgery was performed in five cases and succeeded in four. Although definite mechanisms have not been identified, mechanical fatigue, reversal of aldehyde crosslinks, and immunologic factors may be operative. The pathologic changes include: (1) actual dilation of both graft and mesh with or without intraluminal thrombus and, (2) maintenance of graft diameter with erosion of the umbilical vein and polyester mesh rupture leading to perigraft hematoma and false aneurysm formation. Microscopic examination and infrared spectral analysis confirmed the presence of host-contributed lipid in some specimens. Although this is a low incidence of aneurysm formation, umbilical vein grafts should be selected primarily for patients with limited life expectancy or for whom alternative materials with comparable or superior patency rates are not available or acceptable. Periodic angiography, particularly after 3 or 4 years, is recommended as a routine part of follow-up examinations. Improved graft materials and control of host environmental factors are potential means to reduce the noted degradation.

Aneurysm↗
PubMed1984

Lysis of arterial clot by intravenous or intra-arterial administration of streptokinase.

Intra-arterial thrombolysis with streptokinase was studied in 38 patients. The indications were peripheral thromboembolism in nine patients (group 1), postreconstruction graft thrombosis in 26 patients (group 2) and renal artery thrombosis in three patients (group 3). The intra-arterial route was used for the first and third groups and in 16 of the second group. The intravenous route was used in the remaining ten patients. Lysis was achieved in all of the group 1 and 3 patients. The latter were also treated with percutaneous transluminal angioplasty after dissolution of thrombus of the renal artery. In group 2 patients, lysis was achieved in eight of 16 patients in whom lytic therapy was instituted within seven days of graft closure. There was no lysis in all ten patients in whom elapsed time was more than seven days. Postlytic angiographic visualization of etiologic mechanisms for thrombosis enabled subsequent successful correction in three of five patients in group 2. Attempts to correct graft failure by surgical treatment when lysis had failed were often unsuccessful (12 of 17). Lytic therapy is most effective for acute embolic occlusion and for thrombosis of less than seven days duration. Although there is no difference in drug efficacy by route of administration, a lesser number of complications (such as, fever and hematoma) occurred with intra-arterial infusion. The effectiveness of lysis is also directly related to the collateral circulation and runoff beyond the occlusion. Lysis is not indicated for severe acute ischemia if surgical treatment is an alternative or if it may cause distal embolism as with complete axillofemoral graft thrombosis. Lytic therapy is least effective for graft thrombosis with pre-existent poor runoff.

Aged↗
PubMed1983

Distal arteriovenous fistula as an adjunct to maintaining arterial and graft patency for limb salvage.

Sixty-one distal arteriovenous fistulas (dAVFs) were constructed as adjuncts to tibial and peroneal vascular reconstructive procedures in 58 patients threatened with imminent limb loss. Specific indications for dAVF construction were absent or deficient pedal arches, usually associated with small, calcareous crural vessels. Conventional bypasses had been previously performed in 35 patients. Cumulative graft patency rates were 56%, 39%, and 18% at 6, 12, and 24 months, respectively. For the same intervals, the figures were 56%, 52%, and 52% (P less than 0.001 at 24 months) for nonAVF reconstructions (n = 49). The corresponding cumulative limb salvage rates were 62%, 52%, and 40% for the dAVF group and 78%, 72%, and 72% for the nonAVF group (P less than 0.05 at 24 months). The perioperative mortality rate was 7% (four of 61). Twenty-four amputations were required, of which 16 were below the knee and six despite patent grafts. There was no significant morbidity attributable directly to the dAVF. Cardiac output showed no deviations from normal values. Primary causes of early failure were infection (n = 4), absence of satisfactory veins (n = 6), and inappropriate case selection (n = 7). Intimal hyperplasia led to dAVF closure and graft failure in 13 patients. This study shows that dAVFs can maintain graft patency by diversion of the overload on a high-resistance vascular bed and, secondarily, by augmentation of inflow. Immediate survival of the limb still depends on the arterial runoff, as retrograde venous flow caused by venous valvular incompetence is a delayed development. Adjunctive dAVF is justified in selected cases where conventional bypass failure has occurred or is predictable by increased pedal vascular resistance.

Adult↗
PubMed1982

Influence of failed vascular bypass procedures on conversion of below-knee to above-knee amputation levels.

From 1975 to 1980, 79 major limb amputations were performed from a group of 552 lower extremity vascular reconstructions with glutaraldehyde-stabilized umbilical vein grafts. All amputations were performed in instances in which limb salvage had been the indication for the attempted bypass (n = 520)--an incidence of 15.2%. Twelve of 51 below-knee (BK) amputations were converted to above-knee (AK) levels (crude failure rate, 23.5%). The highest crude failure rate occurred after failed bypass to the popliteal artery (33.3%); the lowest occurred after failed tibial bypass (16.7%), and the peroneal arteries were intermediate (22.2%). In addition to these 12, 28 primary AK amputations were performed. Excluding nine cases judged to require AK amputations before the attempted vascular reconstruction, success/failure rates for the entire series and each of the reconstruction types were calculated. Success, defined as a healed BK stump, occurred least after failed popliteal bypass, 44.5%, compared to 71.4% and 53.8% for the tibial and peroneal groups, respectively. Thus, failure of a popliteal bypass was more apt to lead to an AK amputation (56.5%) than failure of a distal bypass. In fact, tibial bypass failure leading to an AK stump occurred at a frequency (28.6%) almost similar to that obtained by other investigators when no previous bypass had been performed. Comparative cumulative graft patency and limb salvage rate data confirm the value of reconstructive vascular surgery, particularly in the peroneal group where negativism with regard to its clinical usefulness persists. With improved case selectivity and surgical expertise, increasing limb salvage rates can be secured while minimizing the definite morbidity of conversion of BK to AK amputation with failed vascular bypass.

Aged↗
PubMed1981

Morphologic structure of the pedal arch and its relationship to patency of crural vascular reconstruction.

Pedal arch integrity can be determined morphologically and functionally. The former is accessible by contrast studies and intraoperative catheterization, the latter, by flow studies and observation of graft patency. The roengten image of an intact pedal arch corresponds to the anatomic plantar arch. Sixty-four arch studies obtained by adequate intraoperative arteriography were categorized as intact, deficient or inadequate or absent. Patency of crural reconstructions was obtained in 18 of 24 patients with intact arches as compared with 15 of 32, p<0.06, when the arch was deficient. Crural reconstruction in the face of an inadequate or absent arch resulted in predictable graft closure. Qualitative factors, that is, size, calcium and stenotic lesions, are integrally related to over-all graft performance even with intact arches. The deficient arch for tibial and peroneal reconstruction continues as a challenge to the vascular surgeon.

Angiography↗
PubMed1981

Tibial arteriovenous fistula: successful use for limb salvage.

Embolization of atheromatous material from abdominal aortic aneurysms to the distal arterial circuit is a well-recognized clinical entity causing the "blue toe syndrome." A case is presented in which this phenomenon resulted in obliteration of the pedal arch and thrombosis of the tibial arteries. As a result, forefoot gangrene, severe leg ischemia and anterior and posterior compartment syndromes occurred. Salvage of the extremity required an extraordinary approach with the construction of an arteriovenous fistula between the posterior tibial vessels. The literature on the use of therapeutic and adjunctive arteriovenous fistulas and their physiology is discussed.

Aortic Aneurysm↗