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Biomedical subjects

H Dardik

Publications and source records attributed to H Dardik.

At least 73 records · Page 4Linked to original sources
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

The efficacy of dextran 40 in preventing early postoperative thrombosis following difficult lower extremity bypass.

In a randomized, multicenter trial the efficacy of intravenous dextran 40 (D-40; Rheomacrodex) in preventing early postoperative thrombosis was tested in the following difficult lower extremity bypasses: (1) femoropopliteal with poor runoff using autologous vein (AV), (2) femoropopliteal using grafts other than AV, (3) single or sequential bypasses to infrapopliteal arteries, and (4) the above-mentioned bypasses with adjunctive procedures that destroy adjacent endothelial surfaces (e.g., thrombectomy and endarterectomy). Five units of D-40 was administered to the experimental group at 75 to 100 ml/hr, two during and immediately after operation and one each 3 days postoperatively. Antiplatelet drugs were withheld until 1 week after surgery. The overall 1-week occlusion rate was 6.9% (5 of 73) with D-40 and 20.5% (17 of 83) for controls, which is statistically significant. Particularly significant was the difference in group 3: 0% (0 of 28) for D-40 and 27.8% (10 of 36) for controls. In the same time period there were no occlusions in group I and only one occlusion each with AV grafts in both D-40 and control groups, 2.6% (1 of 38). When grafts other than AV were used, the occlusion rate was significantly lower at 1 week for D-40, 11.4% (4 of 35), than controls, 35.6% (16 of 45). By 1 month the protective effect of D-40 was partially lost--15.3% (11 of 72) for D-40 and 20.7% (17 of 82) for controls (no statistical significance). Use of antiplatelet drugs during this period had no discernible effect.

Blood Vessel Prosthesis↗
PubMed1984

Microcomputer-based programs for the practicing vascular surgeon.

An inexpensive microcomputer system can be programmed in BASIC to provide convenient data storage, retrieval, and analysis for the practicing vascular surgeon. A personalized registry program permits input of key patient data that can be processed and retrieved in list form or groupings with operator control of variables. A second program, in which lower extremity revascularization procedures can be analyzed by various parameters, is described. Results can be obtained in life-table formats with comparative statistical analysis. For the private practitioner of vascular surgery, the use of various computer programs will allow management of information for self-assessment, record keeping, teaching, and publication with great accuracy and at significant cost savings. In addition, word processing can increase secretarial output and efficiency. Office management programs are available but need to be individually investigated to determine their use for a particular practice. The major advantages of the microcomputer for the practicing vascular surgeon are personal control and ready access to data that are easy to store, analyze, and retrieve.

Computers↗
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↗
PubMed1980

Adjunctive arteriovenous fistula with tibial and peroneal reconstruction for limb salvage.

Arteriovenous fistulas were constructed as an adjunct to femoral peroneal and tibial bypasses in 13 patients threatened by imminent limb amputation. Previous attempts at conventional vascular reconstructive procedures had failed in nine patients. Deficient or absent pedal arches were noted in all patients, as were poor quality or small crural arteries. Graft patency was achieved in 11 cases and limb salvage in 10. There was no mortality. A steal phenomenon occurred in one patient and was successfully treated by secondary popliteal vein ligation. These preliminary results clearly indicate that an adjunctive arteriovenous fistula can maintain patency in a femoral tibial or peroneal bypass graft while preserving flow into the markedly diseased distal circulation.

Aged↗