Short Vein Research Articles

Prognostic factors for failure of primary patency within a year of bypass to the foot in patients with diabetes and critical ischaemia.

To find out whether we could identify prognostic factors for early failure of bypass to the foot in diabetic patients with critical ischaemia. Retrospective series of consecutive patients. County hospital, Sweden. 43 diabetic patients who had 48 reconstructions for critical ischaemia between 1988 and 1994. 48 elective vein bypass procedures to the feet. Prognostic factors for primary patency. Primary and secondary patency rates at one year were 72% (95% confidence interval (CI) 58 to 85) and 83% (95% CI 71 to 95), respectively. Limb salvage and survival rates at one year were 85% (95% CI 74 to 96) and 86% (95% CI 75 to 96), respectively. Vein graft of questionable quality, major wound healing problems, use of the reversed vein technique, and a narrow lumen (< 1.5 mm) of the recipient artery increased the hazard for failed primary patency by 17.3 (p = 0.003), 6.0 (p = 0.02), 4.7 (p = 0.03), and 3.9 (p = 0.05) times, respectively. Short vein bypass (p = 0.70), translocated or composite veins (p = 0.61), major postoperative oedema of the leg (p = 0.46), or questionable quality of the wall of the recipient artery (p = 0.29), however, had no significant independent effect on the primary patency rate. Early primary patency after bypass to the foot in diabetic patients might improve if veins of questionable quality, major wound healing problems, thin reversed veins from the calf, and narrow recipient arteries can be avoided or handled more proficiently than in the present study.

Calcite precipitation in synthetic veins: implications for the time and fluid volume necessary for vein filling

Although calcite is a common vein-filling mineral in rocks, there has been little understanding of the kinetics of vein-filling that gives a quantitative estimation of the fluid volume and time needed for calcite vein formation in subsurface fracture systems. A new experimental system capable of simulating calcite precipitation in veins was used to determine the influences of flow velocity and initial solution saturation state on the quantitative precipitation pattern of calcite in synthetic veins. Results are in relatively good agreement with the model predictions. Use of a Mn 2+ tracer indicated that even at low concentrations manganese can have a substantial effect on the morphology of the calcite precipitate. Our model predicts that an extremely large volume of fluid is required to produce calcite veins in nature; typically 10 5 to 10 6 for a fluid/calcite volume ratio for formation of thin short veins. The model also predicts the time necessary for vein filling is thousands to millions of years, and is highly variable depending on factors such as fluid saturation state, flow velocity, vein dimension, and the precipitation kinetics that can differ under subsurface conditions.

The utility and durability of vein bypass grafts originating from the popliteal artery for limb salvage

Short vein grafts originating from sites distal to the common femoral artery have been reported to be useful in selected patients with tibial artery disease. From 1987 to 1993, we performed 504 consecutive infrainguinal vein bypass grafts, of which 56 (11%) originated from the popliteal artery, 25 above and 31 below the knee. The patients were 16 women and 37 men, with a mean age of 62.4 years. Eighty-seven percent were diabetic, 57% had clinically obvious coronary artery disease, and 28% had end-stage renal disease (ESRD). The indication for surgery was ulceration or gangrene in 93% of cases. We preferentially used reversed greater saphenous vein harvested from the thigh to optimize conduit quality and avoid lower leg wound complications. The outflow artery sites were: dorsal pedal (17), posterior tibial (14), peroneal (10), anterior tibial (8), lateral or medial plantar (5), and sequential tibial (2). All patients were followed postoperatively with serial duplex surveillance. The mean follow-up was 12.5 months (range 1 to 66). In-hospital mortality was 5.4%. Mortality at 24 months was 19% overall and 38% in patients with ESRD. Limb salvage was 77% at 3 years, 92% in patients with normal renal function versus 59% in those with ESRD (P < 0.003). Primary graft patency by life-table analysis was 94% at 1 month and 84% at 3 years. Five patients with patent grafts required amputation, 4 early and 1 late. Eight months after surgery, 1 patient (1.8%) developed superficial femoral artery stenosis which was diagnosed by duplex surveillance and successfully treated by percutaneous transluminal balloon angioplasty. Vein bypass grafts originating from the popliteal artery are effective and durable. Proximal disease progression rarely poses a significant threat to long-term graft patency. Patients with ESRD, blind tibial outflow tracts, and extensive forefoot lesions appear to be at increased risk of limb loss even with continued graft patency.

Is there a conduit of preference for a bypass between the carotid and subclavian arteries?

The conduit of choice for a bypass between the carotid and subclavian arteries remains controversial. We retrospectively evaluated 32 patients who underwent bypass between the carotid and subclavian arteries. Perioperative mortality was limited to a single patient who sustained a myocardial infarction. Long-term follow-up (mean: 46 months) revealed an 87% stroke-free survival rate, a 74% neurologic symptom-free survival rate, and a 77% primary patency rate at 5 years. No overall difference was discerned between a prosthetic or autogenous vein conduit. However, in bypasses constructed from the subclavian artery to the level of the carotid bifurcation, 100% (nine of nine) of vein bypasses remained primarily patent compared with 40% (two of five) of prosthetic grafts (p < 0.05). No distinct patency difference was identified between a short vein or a prosthetic bypass constructed between the proximal common carotid artery and subclavian artery. A vein bypass results in superior patency compared with a prosthetic graft for longer bypasses constructed from the subclavian artery to the carotid artery bifurcation.

Prospective randomized multicenter comparison of in situ and reversed vein infrapopliteal bypasses

We have performed a prospective, randomized, multicenter study to compare in situ and reversed vein grafts for long limb salvage bypasses from the proximal thigh to an infrapopliteal artery. Three hundred eighty-four patients required an infrapopliteal bypass for critical lower extremity ischemia. Of these, 259 were excluded because a short vein bypass was performed or because the vein was considered inadequate. The remaining 125 patients had a randomized vein bypass, 63 reversed, 62 in situ. The two groups were similar with regard to risk factors, indications, graft dimensions, and outflow. Secondary patency at 30 months was similar for both techniques: reversed 67% ± 9% (±SE); in situ 69% ± 8%. For veins ≤3.0 mm in minimum distended diameter 24-month patency rates were 61% ± 22% for 12 in situ veins and 37% ± 29% for 10 reversed veins (p > 0.05). Angiographic evaluation of failing grafts revealed lesions similar in type and frequency in both types of grafts. These included focal (in situ, n = 4; reversed, n = 7) and diffuse vein hyperplasia (in situ, n = 2; reversed, n = 1), and inflow and outflow stenoses (in situ, n = 4; reversed, n = 3). The incidence of wound complications and the mortality rate were similar for the two groups. These data show no significant difference in overall patency rates for the two types of vein grafts at 212 years. Because of the poor preliminary patency of reversed vein grafts ≤3.0 mm in minimum distended diameter, we suggest the in situ method be used preferentially when such small veins are encountered. Thirty percent of patients requiring a long infrapopliteal bypass had no vein suitable for an in situ graft, although an ectopic vein bypass was feasible. Thus surgeons performing these operations should be adept at both procedures.

Short Vein Grafts in Limb-saving Arterial Reconstructions

In the management of limb-threatening infrainguinal arteriosclerosis, the short vein graft is a feature of distal-origin bypass procedures from the superficial femoral and popliteal arteries to more distal arteries. These procedures, which can only be performed in selected patients, have patency rates equivalent to those of comparable bypasses from the common femoral artery. Other advantages include the increased availability of the shorter vein graft segment that is required. Two newer operations that use short vein grafts are tibio-tibial bypasses and bypasses to isolated segments of infrapopliteal arteries. The authors' initial experience with these two procedures includes encouraging patency and limb salvage rates for periods up to 2 years in patients for whom there was no other therapeutic option short of amputation.

Reconstruction for the Vertebral Artery Stenosis at its Origin

Eight patients with vertebral artery (VA) stenosis at its origin were surgically treated by a new reconstructive technique. Two patients suffered vertebrobasilar transient ischemic attacks, and five had brainstem and/or cerebellar infarction. All patients had multiple stenotic lesions, including bilateral VA stenoses in one and unilateral VA stenosis plus contralateral VA occlusion in seven. They underwent a subclavian artery to VA bypass using a saphenous short vein graft with external shunting. Postoperatively, no patients had aggravated neurological symptoms, and angiography showed all bypasses to be patent. One had an episode of transient loss of consciousness 8 months postoperatively, but the others showed no episodes of ischemia during an average follow-up period of 2 years and 10 months. The results indicate that this procedure is safer and more useful than other surgical procedures.

Recurrence of Varicose Veins Following Surgery

Analysis of 436 recurrent varicose veins shows that the main cause is an inadequate operative technique that fails to ligate the saphenous veins flush to the femoral or the popliteal veins. The recurrence may also be due to a faulty diagnosis that over looks an incompetent short saphe nous vein or incompetent perfora tors. A careful clinical examination and complete investigation through echography and venography are needed. Reoperation should be per formed in order to obliterate all the points of reflux. The surgical approach to the re maining stump of a saphenous vein is very difficult through dense scar tis sue and lymph nodes closely adherent to the recurrent veins, which are fragile and thin-walled. It is a real challenge to the surgeon and requires a great deal of experience and opera tive skill.

Right renal vein extension technique in human kidney transplantation.

A technique for renal vein extension in right kidney transplantation is described. The use of this method allows to avoid some technical difficulties in the transplantation of kidneys with short renal vein and multiple arteries. The short renal vein, even in the presence of multiple arteries, should not by itself be regarded as a barrier to successful cadaveric kidney transplantation. By using all available kidneys for transplantation, regardless of the type of anatomical abnormalities, we were able to raise the number of transplantations in our material by 25%.

Factors contributing to success and failure of femorotibial bypass grafts.

AbstractFemorodistal bypass grafting is an important technique in the armamentarium of vascular surgeons, and it has been found that the cost of such procedures justifies their performance in patients who have sustained critical ischemia. Graft material remains the most important factor in causation of graft failure, with all prosthetics having disadvantages when compared to the saphenous vein. In attempts to use biological materials, both bovine heterografts and human umbilical vein grafts have been seen to form aneurysms and undergo thrombosis. Meanwhile, many variations on the theme of prosthetic grafts have been tried and found wanting when used as bypasses from the femoral artery to the distal circulation. Among configurations tried have been polytetrafluoroethylene with and without external support; Dacron® in woven and knitted format, with or without internal and external velour; and combinations of these. As patency rates of these reconstructions have proven inferior to others using the saphenous vein, attempts have been made to extend the use of autogenous biologic material. Such attempts have included cephalic vein bypass grafts, short vein bypass grafts originating distal to the femoral artery, deep veins used as grafts, and the in situ bypass. Lately, it has been recognized that the in situ bypass, when compared to concurrent controls, shows no significant advantage to the popliteal level but is the technique of choice when distal anastomoses are at or distal to the midcalf. Compositesequential bypasses represent another technique developed to utilize the autogenous vein as a distal segment. While this has increased the rate of patency of distal bypass grafting, other aids to patency such as use of anticoagulants, antiplatelet agents, and adjunctive arteriovenous fistula have not. Dynamics of the coagulation system show an intrinsic change in patient status toward coagulation in the postoperative period, and although this factor is of some significance in causing early graft thrombosis, technical defects do not seem to play an important part. This review details some of these important causes of graft failure and places them in proper perspective.

Short vein grafts: A superior option for arterial reconstructions to poor or compromised outflow tracts?

To determine whether vein graft length is a factor that influences infrapopliteal bypass patency, we reviewed 237 consecutive reversed saphenous vein bypasses performed because of critical ischemia during a 5-year period. One hundred seventeen long vein grafts (LVGs) were longer than 40 cm (42 to 92 cm, mean 60.9 ± 9 cm) and 120 short vein grafts (SVGs) were 40 cm or shorter (6 to 40 cm, mean 24.7 ± 8 cm). Ninety-three percent of the LVGs originated from or were proximal to the superficial femoral artery (SFA) whereas all of the SVGs originated at or distal to the SFA. The cumulative patency rate for LVGs at 3 years was 45% and for SVGs was 63% (p < 0.025). In the absence of an intact pedal arch, 3-year patency rates for LVGs (51 cases) and SVGs (78 cases) were 22% and 53%, respectively (p < 0.01). High intraoperative outflow resistance measurements (>0.7 mm Hg/ml/min) were encountered in 25 cases. Of these, occlusion within 6 months occurred in six of seven cases with LVGs and in only 8 of 18 cases with SVGs (p < 0.05). Wound complications at vein harvest sites occurred in 17% of LVGs and in only 6% of SVGs (p < 0.01). Of 16 additional cases in which a proximal patch angioplasty or percutaneous transluminal angioplasty was performed tandem with a short distal vein graft, four occluded (less than 6 months) and 12 remained patent from 3 to 43 months (mean 12.6 months). Thus SVGs, in addition to increasing vein utilization and decreasing wound complications, have superior patency rates, particularly when used in bypasses to disadvantaged outflow tracts. Early results with tandem procedures are encouraging.

Tibiotibial vein bypass grafts: a new operation for limb salvage.

Tibiotibial bypasses were performed with short (8 to 33 cm) segments of reversed autologous vein in 14 patients who did not have longer segments of usable vein. All patients faced imminent amputation unless they had an effective revascularization. Two patients died, one within 1 month of operation. One patient required below-knee amputation despite a patent bypass. Eleven patients (79%) have a patent bypass and a functional limb 6 to 50 months after operation. These good patency results even with several grafts inserted into isolated segments of tibial arteries, some with incomplete plantar arches, suggest that these short vein grafts may be superior to other vein grafts. Tibiotibial bypasses may improve limb salvage results in otherwise difficult circumstances.

Tibiotibial vein bypass grafts: A new operation for limb salvage

Tibiotibial bypasses were performed with short (8 to 33 cm) segments of reversed autologous vein in 14 patients who did not have longer segments of usable vein. All patients faced imminent amputation unless they had an effective revascularization. Two patients died, one within 1 month of operation. One patient required below-knee amputation despite a patent bypass. Eleven patients (79%) have a patent bypass and a functional limb 6 to 50 months after operation. These good patency results even with several grafts inserted into isolated segments of tibial arteries, some with incomplete plantar arches, suggest that these short vein grafts may be superior to other vein grafts. Tibiotibial bypasses may improve limb salvage results in otherwise difficult circumstances.

Short vein grafts for cerebral revascularization.

Experience with the use of a short saphenous vein bypass graft for cerebral revascularization is reviewed. Twenty patients with symptomatic atherosclerotic occlusive disease underwent a total of 21 bypass procedures. Cerebral revascularization was performed using a short (5 to 10 cm) saphenous vein graft (SVG) extending from the superficial temporal artery (STA) trunk anterior to the ear in 19 bypasses, or from the occipital artery (OA) immediately behind the mastoid process to the posterior temporal or angular branch of the middle cerebral artery (MCA) in two bypasses. The early patency rate for the SVG bypasses was 90%. Two of the four patients with SVG occlusion were found to have substantial resolution of a severe inaccessible internal carotid artery stenosis that was present preoperatively. Filling of multiple major branches of the MCA through the SVG was seen in 90% of patients on late postoperative conventional angiography. The STA trunk or proximal OA was consistently found to be enlarged on the late studies. None of the patients had recurrence of cerebral transient ischemic attacks. The procedure may be useful as a primary means of cerebral revascularization or as an alternative approach when a scalp artery cannot be used because of its small size, severity of arteriosclerotic changes (a common occurrence), or damage during its dissection. Cerebral blood flow studies suggest that the use of a short SVG has a more favorable effect upon the cerebral circulation than the conventional bypass procedure.

The Below- Knee Transposition of a Vein Bypass— A New Therapeutic Principle

The autologous femoro-popliteal vein bypass is a proven treatment concept for the correction of the chronical, and more seldom, of the acute arterial occlusion with good long-term results. 1,2 Recurrent operations show a clearly worse prognosis than the first opera tion. The reasons are the technical difficulties of the revision, the absence of an autologous vessel graft and the less favourable prognosis of the lengthy desob literation, which is recommanded by certain authors as second operation.3,4 The pseudo-recurrent occlusion represents a rather rare indication for a new opertion. Because of an obliteration of the outflow artery, it is considered clinically and oscillographically as a recurrent occlusion. Only the direct Doppler-ultrasound-sonography or the angiography show the patency of the primary bypass, which can flow through small collateral vessels or backward over the distal anastomosis. This paper is meant to be a contribution to the operative treatment of this occlusion kind in case of missing autologous graft after a short femoro-popliteal vein bypass.

Dolores Creek, Yukon; a disseminated copper mineralization in sodic metasomatites

The Dolores Creek mining area situated in the Proterozoic core of the Wernecke Mountains (northeastern Cordillera, Yukon) contains various types of copper, cobalt, and uranium mineralization in altered metasediments and diorite dikes.The 4,000 to 5,000-m-thick succession of Proterozoic rocks consists of two major sequences separated by an angular unconformity. These sequences crop out in a complex northeast-trending, northeast-plunging anticline.The lower part of the older, lower to middle Proterozoic sequence underlies most of the map area and consists of a thick, monotonous pile of marine siltites intergraded with argillaceous quartzites, silty argillites, and impure carbonates. These grade upward into argillites, impure arenites, and at the top into thick bedded, spectacularly orange-weathering dolomites. The metamorphic grade reaches the lower greenschist facies near the base and diminishes upward. Late Proterozoic (?) diorite or gabbro dikes are common in places.The younger, upper Proterozoic sequence occurs as erosional remnants in the immediate vicinity of the Dolores Creek area. Basal purple and green shales are its characteristic lithology.A conspicuous feature of the Dolores Creek area and of the Proterozoic terrane elsewhere in the Wernecke and Ogilvie Mountains is the widespread presence of altered breccias and pseudoconglomerates in Proterozoic metasediments. The breccias are both semiconformable and discordant, gradational to sharply outlined, and occur as elongate masses and lenses along faults or on strike continuations of diorite dikes.Most breccias are hydrothermally altered. In the Dolores Creek alteration-mineralization center, a roughly elliptical area 6 X 4 km has been altered into a central core of albite-(chlorite) metasomatites of syenitic appearance grading outward into albite-chlorite metasomatites with relict breccia fabrics; to fine albitized metasiltites and metacherts; to (albite)-paragonite + or - sericite, carbonate metasomatites; to quartz-sericite rocks; and finally spotted phyllites.Widespread, but so far uneconomic, mineralization within and around the Dolores Creek alteration-mineralization center is dominated by chalcopyrite which occurs with specularite as pervasive disseminations and fracture fillings in sodic metasomatites associated with breccias (Porphyry prospect), hair-thin bedded replacements in altered metasediments adjacent to diorite dikes, veins, and replacement masses in carbonate rocks. Cobaltite occurs in short discontinuous veins, and a pitchblende occurrence along fractures in altered breccias has been explored recently.The Porphyry occurrence resembles in some respects porphyry copper deposits, but the alteration zonality is reversed: the core of Na-feldspathization grades outward into Na-phyllic, K-phyllic, propylitic, and carbonatization zones. The geochemistry of mineralization at Dolores Creek shows many parallels with mineralized spilites, particularly with the homomineralic spilites described by Amstutz. The diorite dikes and their parent magmatic body are considered to have been the source of most metals and of the mineralizers.

The Vascularization of the Rat Pineal Organ

Publisher Summary From the angioarchitectonics, this chapter shows that the rat pineal is a densely and uniformly vascularized organ with a separate arterial supply. The venous outflow is directly in the great cerebral vein where also the median parts of the occipital poles of the hemispheres drain with veins, the appearance of which indicate the possibility of a large blood flow. In view of this and of the immediate drainage in the overlying sinus confluens, the hypothesis that backflow might take place in the great cerebral vein, eventually reaching the choroid plexus, does not seem feasible. The vascular system of the rat pineal organ was studied with various injection techniques. From the observations done with the light microscope and SEM, it was concluded that there is an independent arterial supply consisting of up to four branches of the posterior cerebral artery. The capillary network is at least as dense as in the cerebral cortex, and the venous drainage consists of 12-16 short veins, all draining in the great cerebral vein, and thereafter, via the confluens sinuum immediately in the systematic venous circulation.

Reversed autogenous saphenous vein by-pass from the common to the deep femoral (profunda femoris) artery.

Abstract Extended deep femoral angioplasty is an invaluable method of saving a limb especially where a femoro-popliteal vein by-pass is not possible because of a poor run-off. Atherosclerosis in the deep femoral artery often extends for more than 10 cm. In such cases we have preferred to perform a short vein by-pass than an extensive endarterectomy and patch graft. Our experience is described of 6 such cases, in 5 of whom amputation was avoided.

Polymorphism at the ebony locus of Drosophila melanogaster and population fitness.

ARSON (1957) suggested that the biomass (wet weight of adults) produced per unit time may be used as a measure of the fitness of a population. Various workers (e.g. CARSON 1958; BEARDMORE, DOBZHANSKY, and PAVLOVSKY 1960; DOBZHANSKY and PAVLOVSKY 1961) have shown the population size, and the number and weight of adults emerging in a given time to be greater in populations polymorphic for a number of loci or for chromosomal inversions, than in corresponding monomorphic populations. By this measure of fitness, polymorphic populations had higher fitness than monomorphic populations. For several recessive genes in D. melanogaster, apparently stable equilibrium gene frequencies have been found in experimental populations segregating for the recessive and its wild-type allele, giving rise to a single locus polymorphism (e.g. thread ( t h ) , HEXTER 1955; sepia ( s e ) , cardinal ( c d ) , short vein (shv) , brown ( b w ) , raised ( r sd ) , RASMUSSEN 1958; sepia ( se ) , spineless ( s s ) , rough ( T O ) , CARSON 1958; cinnabar ( c n r ) , FRYDENBERG and SICK 1960,1962; and ebony ( e ) , see below). Such cases provide convenient material for investigation of heterosis and polymorphism. The most widely studied of these loci has been ebony, for which an apparently stable polymorphism has been reported for various alleles ( L’H~RITIER and TEISSIER 193 7; KALMUS 1945 ; TEISSIER 1947; CARSON 1958; RASMUSSEN 1958; ZURCHER 1962,1963; and MOREE 1963). In Experiments 1 and 2 reported here, we have investigated further the apparent stability of an ebony polymorphism, and the effect of this polymorphism on population numbers, number of flies emerging from a medium jar, rate of development. and sex ratio. The selective changes in the frequencies of genotypes in populations will be affected by any interactions between the genotypes affecting viability or other fitness components. BEARDMORE (1963) found that the increased fitness of polymorphic populations of D. pseudoobscura was in part due to favourable interactions between larvae of different genotypes affecting their viability. Similar interactions have been found in D. melanogaster (LEWONTIN 1955) and in D. busckii (LEWONTIN and MATSUO 1963), WEISBROT (1964) suggested these interactions were due to some accumulated waste product of the larvae. The possibility of such interactions affecting viability at the ebony locus, and contributing to the development of polymorphism, was also investigated (Experiment 3).

The Influence of Selection and Temperature On a Mutant Character (CiD) in Drosophila Melanogaster

Abstract1. In the mutant ciD of Drosophila melanogaster the relative length of the 4th vein was used as a quantitative character. Divergent selection during 30 to 40 generations for long and short vein length was practised in three unrelated base populations. 2. Selection progress continued through about 20 to 30 generations, sometimes with alternating periods of advance and stability. In all three base populations heritability was approximately 0.3, and similar selection limits were reached far beyond the ranges of the base populations. 3. During the course of selection there were striking changes in the appearance of the frequency distributions (bimodality), particularly in the lines selected for a long, i.e. more normal vein. 4. An explanation for this is proposed, which is based on the assumption that the factors (genetic or environmental) influencing the expression of a character are in their effect dependent on the relative length of the vein. Temperature experiments are described which strongly support this hypothesis. Expression, in response to temperature, appeared to be very sensitive to change in a particular expression range. 5. This view implies that vein determination is governed by two at least partially independent genetic systems, one controlling the relative length of the vein and the other relating modifying influences to their phenotypic effects. 6. Thus, the variability in this mutant character seems to be governed in large measure by the properties of its developmental system. 7. The results are discussed in terms of their significance in the fields of quantitative genetics, developmental genetics, and evolution.