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Biomedical subjects

H Dardik

Publications and source records attributed to H Dardik.

At least 19 recordsLinked to original sources
PubMed1992

Comparative efficacy of topical hemostatic agents in a rat kidney model.

The efficacies of four topical hemostatic agents were compared in a rat model employing a standardized renal injury. The materials used to effect hemostasis were oxidized cellulose, microfibrillar collagen powder, positively charged modified collagen, and single donor heterologous fibrin glue. Animals that were treated only with surgical gauze served as controls. Hemostasis was achieved by application of one of the topical hemostatic agents plus moderate digital pressure. The time necessary to achieve complete hemostasis was recorded for each animal. Control animals bled profusely and suffered an increased postoperative mortality rate compared with the experimental animals. Microscopic studies demonstrated progressive healing of the injuries with varying degrees of inflammation and scar formation. Fibrin glue was by far the most effective agent in controlling hemostasis. The collagen materials, though effective, required a longer time to control bleeding and did not differ statistically in their activity from one another.

Administration, Topical↗
PubMed1979

The role of the peroneal artery for limb salvage.

Peroneal artery revascularization was performed in 61 cases for limb salvage and compared to a comparable group of 89 tibial artery reconstructions. Preoperative arteriography is essential to define runoff quality and pedal arch integrity. Intraoperative arteriography and flow determinations minimize failures due to technical error and provide some indication of the prognosis for graft patency. Failure to augment flow by at least 50% suggests pedal arch deficiency and is predictive for early graft closure. Cumulative patency for peroneal bypass was 55 +/- 8% at 1 year and 38 +/- 10% at 30 months compared to 63 +/- 6 and 59 +/- 7% for tibial reconstructions at the same time intervals. Most graft failures occurred within the first six months. Nineteen peroneals have been followed for more than one year with only three failures occurring. Improved criteria for case selection resulted in an 80% decrease in the number of failed grafts for the second half of this series. A similar reduction was noted for secondary operations. Results obtained with good quality saphenous veins (37 +/- 13% at 30 months) and glutaraldehyde tanned umbilical veins (53 +/- 11%) depend more on technical, pathologic and biologic factors than on the particular graft material employed. The mortality rate at 30 days was 3.3% and compared favorably with other limb salvage procedures and with primary amputations. Cumulative patient survival with functional limbs was 79 +/- 9% at 30 months and was distinctly superior to reported data on survival of amputees. A cumulative limb salvage rate of 79 +/- 6% at 30 months for the peroneal group makes such reconstructions definitely favorable to uniform limb ablation.

Amputation, Surgical↗
PubMed1979

Synchronous aortofemoral or iliofemoral bypass with revascularization of the lower extremity.

Bypassing aortoiliac stenosing lesions to the profunda femoria alone, even with extensive end-arterectomy and angioplasty of the latter, will not provide predictable excellent results in the presence of gangrene and occlusion in the femoral popliteal system. With severe pregangrene and rest pain, residual ischemic complaints are also common, and if lesions are present, healing is incomplete or, at best, delayed. Alternatively, femoropopliteal or tibial bypass, in the presence of even moderately diminished inflow, is subject to either early or delayed closure, unless proximal repair is also performed in appropriately selected patients. Synchronous correction of tandem lesions involving the aortoiliac and femoropopliteal segments should, therefore, be considered for limb salvage only and particularly in the presence of focal gangrene, excision or debridement of which can be anticipated to heal after successful bypass. Major diminution in femoral inflow usually indicates the need for proximal repair only, even in the presence of distal lesions. Noninvasive studies and intraoperative flow determinations are not uniformly helpful in patient selection. Synchronous aortofemoral or iliofemoral and femoropopliteal or tibial reconstructions were performed upon 38 patients, 15 of whom had no prior vascular operation and 23 of whom had previously undergone either aortofemoral or femoropopliteal bypasses that had failed. Graft patency for all patients was 76 per cent, and although it was better for the patients in group 1 than for those in group 2, no statistical significance existed between the two groups. Improved patient selection and criteria for performing synchronous reconstructions might originally have been of benefit for the patients in group 2, avoiding more difficult secondary repairs. It must be emphasized, however, that synchronous reconstructions should not be done routinely in the presence of multilevel disease. Rather, specific indications do exist and should be considered on an individual basis.

Aged↗
PubMed1978

Evaluation of glutaraldehyde-tanned human umbilical cord vein as a vascular prosthesis for bypass to the popliteal, tibial, and peroneal arteries.

One hundred and thirty-one reconstructions to the popliteal (n = 80), tibial (n = 26), and peroneal (n = 25) arteries were performed using glutaraldehyde (GA)-tanned human umbilical cord veins. Cumulative patency rates to 20 months, calculated by the standard life-table method were 84.8%, 74.0%, and 49.6% for popliteal, tibial, and peroneal reconstructions, respectively. The latter included many of the early cases with extremely advanced obliterative atherosclerosis and gangrene. These results are equivalent and even superior to those obtained with saphenous veins, particularly when the cases are analyzed in distinct clinical and pathological categories. The quality of the runoff was the major determinant in obtaining long-term patency and limb function. The primary factor accounting for graft closure was progression of the atherosclerotic process in the distal circulation. No failures could be attributed directly to the graft. This clinical experience confirmed previous data showing the unique properties of the GA-tanned umbilical vein. It is anticipated that longer-term follow-up will continue to show the superior qualities of this new vascular substitute.

Aged↗
PubMed1978

Evaluation of intraoperative arteriography as a routine for vascular reconstructions.

A retrospective analysis of 391 intraoperative arteriograms performed after reconstruction operations on the carotid, aorta and lower extremity vasculature showed the value of incorporating this procedure as a routine only for the last mentioned site. Identification and correction of inadequacies due to technique are possible. Revisions in technique based upon these experiences have significantly diminished their incidence. Routine intraoperative arteriography for revascularization procedures of the lower extremity has further enabled us to classify reliably the runoff and correlate these findings with subsequent graft patency. Late graft closure, predominantly due to progressive or accelerated obliterating atherosclerosis in the distal circulation, occurred almost exclusively within the first year following reconstruction in those patients identified as having poor runoff by intraoperative arteriography. This group, in particular, should be closely monitored by noninvasive physiologic means and even post-operative arteriography to enable either prophylactic or therapeutic correction. In some instances, based upon intraoperative arteriography or subsequent studies, fruitless and potentially harmful reoperative vascular procedures may be obviated.

Angiography↗
PubMed1977

A simple guideline to facilitate axial alignment of vascular grafts.

The proper orientation of vascular prostheses is essential for successful performance of vascular reconstructions. To prevent axial rotation of grafts, particularly in long tunnels such as in the axillo-femoral or subsartorial position, vascular prostheses with a simple guideline incorporated within their fibers were employed. The advantages of these grafts are discussed.

Aorta, Abdominal↗
PubMed1976

Human umbilical cord. A new source for vascular prosthesis.

Reconstructions were performed to the popliteal, tibial, and peroneal arteries employing a modified umbilical cord vein prosthesis. The latter was obtained from human cords and was made available as an onshelf graft for surgery following glutaraldehyde tanning. The early patency and limb salvage rates are equivalent to those obtained with autogenous saphenous veins. Additional benefits include significant decreased operative time and morbidity. It is also probable that this new graft may be resistant to biodegradation and therefore may obviate many of the causes for late failure that occur with the use of living biologic tissues or collagen tubes. Long-term follow-up and study are essential to validate the results obtained thus far and to assess the potential of this new graft in a variety of vascular reconstructions.

Aged↗
PubMed1976

Arteriovenous fistulas constructed with modified human umbilical cord vein graft.

Arteriovenous (AV) shunts were created using modified umbilical veins in baboons. The shunts consisted of veins removed from human umbilical cords tanned by either dialdehyde starch or glutaraldehyde 2% and surrounded with a polyester fiber mesh. Twelve fistulas were constructed employing the femoral or axillobrachial vessels. Six of the seven straight axillobrachial shunts remained patent for up to four months during the period of study. One of two loop fistulas and three femoral AV fistulas thrombosed because of kinking. There were no infections, mural disruptions, or aneurysm formations. Anglogram results and histologic studies confirmed the maintenance of graft function, morphologic appearance, and tolerance to repetitive punctures.

Animals↗
PubMed1976

Successful arterial substitution with modified human umbilical vein.

Human umbilical veins were prepared as vascular grafts by tanning with dialdehyde starch or gluteraldehyde and by structural re-inforcement with an outer polyester fiber mesh. These grafts were implanted in baboons in the aortoiliac position for periods of 3 days to 9 months. There was no aneurysm formation and there was an excellent maintenance of patency as well as function. Histologic evaluation of the graft materials showed a dense collagen layer within the encircling polyester fiber mesh. A multicellular subintimal layer formed a discrete inner capsule. The inflammatory response with the umbilical component was insignificant. There was no evidence of rejection. This study suggests that the modified umbilical vein can serve as a satisfactory blood conduit. Experience with three short-term clinical implants supports the applicability and potential for this new vascular graft.

Animals↗
PubMed1976

Intravenous rupture of arteriosclerotic aneurysms of the abdominal aorta.

Intravenous rupture of abdominal aortic aneurysms occurs infrequently but should be considered with the coexistence of severe congestive failure, anasarca, and abdominal bruits. Six patients are presented with four survivors. In only two patients was the diagnosis considered preoperatively without angiography. Two were variants in that thrombus occluded the fistula, thereby negating findings usually manifested clinically. Diagnosis of this type can be made only during operation when copious venous bleeding ensues with evacuation of the aortic thrombus. Careful fluid management and prompt surgery are prerequisites to obtaining a successful outcome. Repair is accomplished easily by suturing the fistula from the aortic aspect, but care is required to avoid dislodgement of thrombus and atherosclerotic debris resulting in pulmonary embolism.

Aged↗
PubMed1976

Revascularization of the peroneal artery.

In the absence of a suitable popliteal or tibial arterial system with direct communication to a pedal arch, the peroneal artery may be used for distal anastomosis with the expectation of achieving patency rates exceeding 60 per cent. Morbidity can be minimized by careful patient selection and by imporved surgical technique and materials. In 14 of 23 peroneal bypasses, patency was maintained compared with 27 to 35 bypasses to the tibial artery system. Limb salvage was 57 per cent for th peroneal artery group compared with 71 per cent for tibial artery reconstruction.

Arteries↗