COMPLICATIONS OF VARICOSE SCLEROTHERAPY OF THE LOWER LIMB
 Vin F.
PhlÈbologie 1999; 52:53-59

COMMENTARY BY:
Mitchel P. Goldman, MD
La Jolla, California, USA

In this paper, the common complications of sclerotherapy are well described along with the appropriate methods for preventing their occurrence and treating complications as they occur. Inherent in the prevention of complications in the treatment of large varicose veins is the use of ultrasound-guided injections pioneered by Dr. Vin and his colleagues in Paris. Indeed, the prevention of extravasation and intra-arterial injection is best done through expert ultrasound-guided injections.

Dr. Vin describes a complication termed "lipothymie." He describes this as a generalized sensation of malaise with the possible development of a vasovagal-type reaction. Dealing with this as well as allergic manifestations from sclerosant solutions are well reviewed along with the methods for avoiding these adverse sequelae. Local complications include excessive inflammatory reactions from inappropriate use of concentrated and/or caustic sclerosing agents. The use of minimal sclerosant concentration is advocated. Helpful suggestions for hastening the resolution of cutaneous pigmentation are presented.

Vin provides a complete description for dealing with the rare complication of injecting the deep venous system and states that the key is preventing the development of deep venous thrombosis. Finally, intra-arterial injection, the most feared complication, is well described. The only difference in Vin's treatment of intra-arterial injections from that reported in a prior comprehensive review is the use of systemic corticosteroids.1

COMMENTARY

Frederic Vin is an experienced phlebologist who has trained hundreds of physicians in proper phlebological techniques, including sclerotherapy. Therefore, it is appreciated that Dr. Vin has put his experience in the use sclerotherapy into a concise paper. This paper is recommended as a general and concise discussion of complications and their treatment. ivdfgol1

REFERENCE

1. Goldman MP. Complications and adverse sequelae of sclerotherapy. In: Varicose Veins & Telangiectasias: Diagnosis and Treatment, 2nd ed. Goldman MP, Weiss RA, Bergan JJ (eds). Quality Medical Publishers, St. Louis, 1999; 300-79.




STRIPPING THE LONG SAPHENOUS VEIN REDUCES THE RATE OF REOPERATION FOR RECURRENT VARICOSE VEINS: FIVE-YEAR RESULTS OF A RANDOMIZED TRIAL
 Dwerryhouse S, Davies B, Harradine K, Earnshaw JJ
J Vasc Surg 1999; 29:589-92

ABSTRACT AND COMMENTARY BY:
Ralph DePalma, MD
Associate Dean and Vice Chairman of Surgery
University of Nevada, Reno
Reno, Nevada

The authors investigated long-term clinical advantages of stripping the long saphenous vein during primary varicose vein surgery. The study consisted of a five-year clinical and duplex scan followup examination of a group of patients randomized either to stripping of the long saphenous vein during varicose vein surgery or saphenofemoral ligation alone. Procedures were done in a vascular unit by consultant vascular surgeons. A total of 100 patients (133 legs) with uncomplicated primary long saphenous vein varicose veins were randomized. Five years later, 78 patients (110 legs) underwent clinical review and duplex scan imaging.

Only three operations for recurrent long saphenous veins were necessary in 3 of the 52 legs from the stripping group versus 12 of 58 legs in the ligation alone group. The relative risk of recurrence was 0.28 with a 95% confidence interval of 0.13 to 0.59 (p = 0.02). Neovascularization at the saphenofemoral junction was responsible for 10 of 12 recurrent veins requiring reoperation. It was also the cause of recurrent saphenofemoral junction incompetence in 12 of 52 stripped veins versus 30 of 58 ligated legs. Relative risk of neovascularization was 0.45 with a 95% confidence interval of 0.26 to 0.78 (p = 0.002). The authors conclude that stripping reduced the risk of reoperation by two-thirds after five years and should be routine for primary longstanding saphenous veins.

COMMENTARY

It has finally been done! This mercifully brief, concisely reported study should settle the debate once and for all as to whether it is better to strip a primary incompetent long saphenous vein or selectively ligate it. I have almost always stripped the long saphenous vein with satisfactory results.

The puzzling aspect to this study is the incidence of groin neovascularization detected by duplex scanning of 50% with stripping and 65% with ligation. In 12 of 52 stripping cases and 30 of 58 ligated cases, neovascularization caused recurrent saphenofemoral junction incompetence. The recurrent veins were large. Neovascularization has not been my experience though perhaps I have simply overlooked it. I have encountered neovascularization in recurrent cases, mostly referred. Its origin is obscure and one wonders whether there is some lymph node factor or whether it simply results from leaving behind vessels which might not be completely ablated by diathermy. It is my practice to ligate all of the veins around the saphenofemoral junction with nonabsorbable sutures.

In keeping with the British tradition, saphenous veins are stripped to only below the knee. The authors make the comment that even in legs that have undergone stripping, 25% have incompetence in the residual distal long saphenous vein. It is my belief, though admittedly a minority opinion, that the vein is best stripped from groin to ankle. The reason is that communicating branches from the below-knee saphenous vein to the posterior arcade are frequent and these communicating branches often relate to incompetent perforators in the posterior arcade. Stripping will result in avulsion of the posterior arcade vessels when done carefully. It is also my belief that complete stripping can be accomplished with minimal risk of neurapraxia if the vein is carefully dissected away from the nerve at the ankle using magnification. An inverting technique can be used (or a very small stripper head) and the vein is removed slowly from above downward and subsequently recovered in the groin.

The authors are to be commended for their diligence and scientific consistency in carrying out this study. It would appear that the controversy is solved. They correctly suggest that reoperation rates tended to occur after the duplex scan at two years and at five years as patients became more conscious of their veins. The authors also comment on the psychological reasons why patients might elect to have their veins treated. Reoperation might have been requested for symptoms brought to light by the duplex scanning.

In the end, an answer has been provided: It is better to strip an incompetent varicose long saphenous vein than it is to ligate it and "cherry pick" along the way. This does not mean that it is wise to strip a competent saphenous vein when other isolated varicose veins are the problem. Differentiation is possible using preoperative duplex scanning.1 The reason for the high incidence of neovascularization and its significance in causing recurrence remains quite mysterious. The data on lower leg recurrence provides yet another challenge for future study. vddep171

REFERENCE

1. DePalma RG, Hart MT, Zanin L, Massarin EH: Physical examination, Doppler ultrasound, and color duplex scanning: Guides to therapy for primary varicose veins. Phlebology 1993; 8:7-11.




PREVALENCE OF VENOUS REFLUX IN THE GENERAL POPULATION ON DUPLEX SCANNING: THE EDINBURGH VEIN STUDY
 Evans CJ, Allan PL, Lee AJ, Bradbury AW, Ruckley CV, Fowkes FGR.
J Vasc Surg 1998; 28:767-76

ABSTRACT AND COMMENTARY BY:
Jan Struckmann
Copenhagen, Denmark

This study describes the prevalence of reflux in the superficial and deep venous systems in the Edinburgh population and the relationship between patterns of reflux and the presence of venous disease on clinical examination. The study method was a cross-sectional survey of men and women ranging in age from 18 to 64 years, randomly selected from 12 general practices. The presence of varicose veins and chronic venous insufficiency (CVI) was noted on clinical examination and patients were classified according to the Basle Study classification. CVI grades 1 to 3 were established (the study was initiated before the CEAP classification system was established).

The duration of venous reflux was investigated by duplex scanning in eight vein segments on each leg. Patients were investigated standing at a 45-degree angle. Results were compared using cutoff points for reflux duration (RD) of 0.5 seconds or more and more than 1.0 seconds to define reflux.

There were 1566 study participants, 867 women and 699 men. The prevalence of reflux was similar in the right and left lower extremities. The proportion of participants with reflux was highest in the lower thigh greater saphenous vein (18.6%/17.5%) followed by aboveknee popliteal segments (12.3%/11.0%), belowknee popliteal segments (11.3%/9.5%), upper greater saphenous vein (10.8%/10.0%) common femoral vein (8.0%/7.8%), lower superficial femoral vein (6.6%/6.4%), upper superficial femoral vein (5.2%/4.7%), and lesser saphenous vein 5.6%/4.6%).

In the superficial veins, the cutoff point for RD was insignificant while in the deep veins the prevalence of reflux was 2 to 4 times greater for RD > 0.5 seconds rather than RD > 1.0 seconds. Men had a higher prevalence of reflux in the deep veins than women (p < 0.01). The prevalence of reflux increased with age. Patients with venous disease had a significantly higher prevalence of reflux in all vein segments than those without signs of venous disease (p < 0.001). The age-adjusted prevalence of CVI was 9.4% in men and 6.6% in women (p < 0.05).

COMMENTARY

This study provides important epidemiological information on the presence of reflux in the general population. Although participants with signs of venous disease had a higher prevalence of reflux in all vein segments, approximately 12% of those with "no disease" had a reflux duration of less than 0.5 seconds in the popliteal and lower thigh greater saphenous vein segments. The highest sensitivity and specificity was reached for cutoff points for reflux duration at 0.5 seconds rather than 1.0 seconds.

Long-term followup of this cohort of patients may show the significance of reflux to predict future occurrence of venous disease and of complications in those who already have venous disease. ivdfstr1




VENOUS LEG ULCERS: MODERN EVALUATION AND MANAGEMENT
 Zimmet SE
Dermatol Surg 1999; 25:236-41

ABSTRACT AND COMMENTARY BY:
Frank Padberg, MD, FACS
Department of Surgery
Chief, Section of Vascular Surgery
V.A. Medical Center/New Jersey Medical School
East Orange, New Jersey

Optimal care for venous ulceration is succinctly reviewed in this brief article. The basic principles underlying management are well presented as is accurate diagnosis to elucidate the pathophysiological contributions from macrocirculatory and microcirculatory abnormalities. Essential diagnostic features of clinical and noninvasive examinations are summarized.

Since there is no universal approach to the problem of "leg ulcers," the importance of accurate diagnosis is critical. In my own experience, effective surgical options are frequently and easily overlooked in the emphasis on wound management in an outpatient setting. The clinician is taught to be sensitive to recognizing significant nonvenous etiologies of leg ulcer such as malignant degeneration, arterial insufficiency, and systemic diseases such as sickle cell disease or rheumatoid arthritis which are commonly associated with recalcitrant healing. Quite appropriately, individualized management is emphasized, a factor which becomes key in achieving optimal management of leg ulcers.

The central role of compression is emphasized along with practical suggestions to maintain it. Recently introduced options for local wound care include a human skin equivalent (Apligraf ) which is recommended for recalcitrant ulcers of prolonged duration. The authors review the many wound care alternatives along with the observation that this choice remains a matter of clinical judgment. Other less well-established therapies (nutrition, physical therapy, and manual lymphatic drainage) are briefly mentioned but the paucity of real data on their benefits (or lack of) precludes scientific assessment of their validity. Notably, these also included the role of ankle mobility in chronic venous insufficiency, a special interest at our institution.1

COMMENTARY

The primary target audience for this article is presumably general dermatology. However, the text emphasizes the broad professional expertise which may be necessary for the optimal care of these patients. A common error is perpetuated when the "leg ulcer" is treated in a clinic environment by multiple caregivers, each of whom offers different regimens for wound care but each of whom defers comprehensive evaluation. When surgically correctable abnormalities remain undiscovered, the ulcers will predictably recur and the cycle begins again. The author's emphasis on complete and accurate diagnosis (hemodynamic abnormalities, neoplastic, and systemic illness) is well placed since other specialists are likely to become involved earlier if suspicion is raised at the initial evaluation.

The article correctly points out that superficial and perforator vein disease is readily amenable to appropriately directed surgical treatment. Although wound healing is the initial focus, durable freedom from recurrent ulceration is the real mark of success. There is good evidence to support ligation and stripping as a durable treatment. Unfortunately, there is little good data to support sclerotherapy or high ligation along as a durable therapy for venous ulceration.2,3 Although the morbidity of perforator ligation has been substantially reduced by the advent of subfascial endoscopic perforator surgery, its role remains under investigation. Very little indeed is known about the other therapies mentioned above with regard to venous ulceration.

While the focus on wound management should be expected, the author is to be complimented for highlighting the many complex ancillary issues necessary for optimal patient care. Although initial attempts to validate a single growth factor therapy failed, newer products are currently under investigation. Clearly, the question of which dressing is best remains unanswered.

Though recognizing the competing demands imposed by journal space and a comprehensive multispecialty review article, the absence of evidence-based data was disappointing. As well, many of the references were from sources not subject to the peer review process (textbook chapters). This succinct review is too short to be comprehensive; however, it does serve as a good general reference. vdpad171

REFERENCES

1. Back TL, Padberg FT, Araki C, Thompson PN, Hobson RW. Limited range of motion is a significant factor in venous ulceration. J Vasc Surg 1995; 22:519-23.

2. Scriven JM, Hartshorne T, Thrush AJ, Bell PRF, Naylor AR, London NJM. Role of saphenous vein surgery in the treatment of venous ulceration. Br J Surg 1998; 85:781-84.

3. McMullin GM, Coleridge Smith PD, Scurr JH. Objective assessment of high ligation without stripping the long saphenous vein. Br J Surg 1991; 78:1139-42.




MID-TERM RESULTS OF ENDOSCOPIC PERFORATOR VEIN INTERRUPTION FOR CHRONIC VENOUS INSUFFICIENCY: LESSONS LEARNED FROM THE NORTH AMERICAN SUBFASCIAL ENDOSCOPIC PERFORATOR SURGERY (NA-SEPS) REGISTRY
 Gloviczki P, Bergan JJ, Rhodes JM, Canton LG, Harmsen S, Ilstrup DM, and No Am Study Group
J Vasc Surg 1999; 29; 489-502

ABSTRACT AND COMMENTARY BY:
Bo Eklof, M.D.
Straub Hospital and Clinic
Honolulu, Hawaii

This is a two-year followup of the NA-SEPS registry which included 146 patients from 17 centers where subfascial endoscopic perforator surgery (SEPS) was performed. In 71% of limbs this was combined with treatment of superficial incompetence. Perforator incompetence was confirmed by duplex scanning or venography in 88% of limbs. CEAP classification showed that 69% had active ulcerations and 14% had healed ulcerations at the time of surgery. The venous problems had a primary etiology in 62% and a secondary etiology (postthrombotic) in 38%. All patients had incompetent perforators with an incompetent superficial system in 67%, an incompetent deep system in 72%, a combination of the two in 50%, and isolated perforator incompetence in only 5%. The etiology of venous dysfunction was reflux in 93%, obstruction in 4%, and a combination of both in 2%.

The authors set three goals for the study: 1) To determine the efficacy of the SEPS procedure in preventing the recurrence of venous ulcer in patients with advanced chronic venous insufficiency, 2) to identify patients who would most benefit from the interruption of incompetent perforating veins, and 3) to identify patients at highest risk for ulcer recurrence.

The cumulative ulcer healing rate was 88% at one year and 93% at two years. Cumulative ulcer recurrence was 16% at one year and 28% at two years. Postthrombotic limbs had a higher two-year cumulative recurrence rate (46%) than those limbs with primary valvular incompetence (20%).

The study concludes that SEPS with ablation of superficial reflux is effective in healing ulcers in patients with chronic venous insufficiency and that recurrence of ulcers is significant in postthrombotic limbs.

COMMENTARY

In a discussion of the paper, Dr. John Bergan stated that the registry had collected useful information; e.g., that superficial reflux is an important component. The sobering results warrant a reevaluation of the indications for the SEPS procedure. You can almost feel the apprehension as the authors write "patients who are lost to followup, even those with active ulcers, plague attempts at scientific reporting." Also, statistical power is sometimes weak as is shown in Figure 2 in the article which is based on one patient with deep venous obstruction during the last half of the followup time.

The authors should be commended for their attempts to utilize the CEAP clinical score and the clinical outcome scale. The CEAP classification provides a way to focus the diagnostic workup of a patient with chronic venous insufficiency so that proper treatment can be implemented. This study shows that patients with postthrombotic etiology did not benefit much from SEPS. Anatomic distribution, severity of reflux, and obstruction were not registered in this study. This can be done using duplex scanning and plethysmography.

Following a heated debate at the meeting of the American Venous Forum in February 1998, the authors now recommend a prospective, randomized study to define the need for SEPS. Bergan has shown that deep venous reflux disappears in 94% of limbs in which superficial operations are done in early cases. There are indications of the same result with incompetent perforators after ablation of reflux in the saphenous system.

The NA-SEPS Registry has laid the basis for the needed prospective, randomized trial. We need to diagnose and classify patients with chronic venous insufficiency due to incompetent perforators using duplex scanning and perhaps even air plethysmography. I propose a study where patients with postthrombotic etiology be excluded. One group could be randomized for SEPS with concomitant ablation of superficial incompetence while the other group could leave the incompetent perforators for followup. Until we have the results of such a study, I recommend restricting the indications for SEPS to those patients with advanced chronic venous insufficiency with incompetent perforators due to poor, fragile skin or active ulcers. In patients with reasonable skin, we can mark exactly the perforators with the duplex scanner and ligate them through a small skin incision. This would save time and money (the SEPS procedure is very expensive).

So...the registry is dead. VivÈ the trial! ivdfekl1




A CLINICAL AND HEMODYNAMIC INVESTIGATION INTO THE ROLE OF CALF PERFORATING VEIN SURGERY IN PATIENTS WITH VENOUS ULCERATION AND DEEP VENOUS INCOMPETENCE
Scriven, Bianchi, Hartshorne, Bell, Naylor, London
Eur J Vasc Endovasc Surg 1998; 16:148-52

COMMENTARY BY:
Peter Conrad, M.D., F.R.C.S.
Penrith, Australia

This article is an ambitious attempt to prove that when primary deep vein incompetence and perforating vein incompetence are present, a coexisting venous ulcer will not heal and venous function will not improve if incompetent perforating veins are interrupted.

Seven limbs with venous ulcers were chosen for the study. The underlying abnormality in each was deep vein incompetence and perforating vein incompetence. The presence of superficial vein incompetence was excluded by the fact that in each of the chosen limbs, the greater saphenous vein had been previously removed. Deep vein incompetence and perforating vein incompetence were assessed by duplex scanning. Hemodynamic studies included pre- and postoperative (one month) photoplethysmography (PPGRT90). The ulcers were measured for pre- and postoperative healing. The perforating veins were interrupted using three different methods: 1) individual small skin incisions, 2) endoscopic perforating vein interruption (SEPS), and 3) coil embolization. No actual numbers of each method were given.

The postoperative findings at one month indicated no improvement in the hemodynamics of the legs as measured by photoplethysmography (RT90). Also, none of the ulcers had begun to heal and, indeed, some had increased in size. The authors conclude that perforating vein interruption has no role in the management of venous ulcers where the limb is affected by primary deep vein incompetence.

COMMENTARY

This paper underscores the enormous importance of deep vein incompetence, whether primary or postthrombotic, in the pathogenesis of venous ulcers. It is only with the advent of widespread duplex scanning in the last decade that the prevalence and impact of deep vein incompetence on the hemodynamics of the leg, varicose vein treatment, and venous ulcer treatment has been appreciated. It is widely recognized that in those venous ulcers where the underlying chronic venous insufficiency is linked to superficial venous reflux, surgical correction of the superficial system (with or without perforator interruption) will improve ulcer healing and correct lipodermatosclerosis.1

The theory emerging now is that when superficial reflux due to greater and/or lesser saphenous incompetence is absent or has been corrected and there is chronic venous ulcer, this ulcer is more resistant to treatment. The fundamental question is whether interruption of incompetent perforating veins in the presence of underlying deep vein reflux (primary or postthrombotic) will assist in the healing of these ulcers. This study attempts to answer this question in cases where the underlying deep vein reflux is primary. However, the numbers are few (7) and followup short (one month).

Before we abandon perforating vein interruption for venous ulcer associated with deep vein reflux, especially now that the procedure is less invasive with the advent of subfascial endoscopic perforator surgery (SEPS), it would seem timely to have a large well-controlled, multicenter trial. The issues brought up by Scriven should be addressed again with larger numbers and longer followup. This would help in determining whether perforating vein interruption influences the healing of chronic venous ulcers in the presence of deep vein reflux, both primary and postthrombotic. ivdfcon1

REFERENCES

1. Bergan JJ, Ballard JL. Pathophysiology of chronic venous insufficiency. In: Bergan JJ Gloviczki P (eds). Atlas of Endoscopic Perforator Vein Surgery , Springer-Verlag, London, 1997, pp 45-58.


Editor's Note:

 This article was chosen for the Venous Digest because it comes from a very important vascular unit. The conclusion of the presentation is that perforating vein interruption adds little to the care of patients with severe chronic venous insufficiency with venous ulcers. In fact, the postoperative treatment of the patients excluded elastic compression or short-stretch bandaging. In view of that, it is not surprising that the ulcers did not heal and some increased in size. Furthermore, the presentation expresses implied disappointment that the hemodynamics were not affected by perforator vein interruption. Actually, it is not surprising that in limbs with deep vein incompetence, hemodynamic bettering is not regularly seen following any form of therapy. After all, the stigmata of severe venous insufficiency is expressed in the skin where molecular events could very well take place and these would be independent of changes in hemodynamics. It is certainly clear to experienced surgeons that perforator vein interruption combined with careful case selection and meticulous postoperative care has become a major contributor to care of patients with severe chronic venous insufficiency.




COLOR DUPLEX ULTRASOUND IN THE ASSESSMENT OF PRIMARY VENOUS LEG ULCERATION
Yamaki T, Nozaki M, Sasaki K.
Dermatol Surg 1998; 24:1124-28

ABSTRACT AND COMMENTARY BY:
Gy–rgy Acsady, M.D.
Budapest, Hungary

This study was undertaken using color duplex ultrasound to evaluate the severity of superficial valvular incompetence during investigation of 370 lower limbs with primary varicose veins.

The saphenofemoral and saphenopopliteal junctions were assessed with patients in the standing position while the other branches of the venous system were examined in the sitting position. Parameters assessed included the extent and duration of reflux and retrograde peak velocity. Clinical findings were classified according to the CEAP classification. Patients with previous deep venous thrombosis or arterial diseases were excluded.

Of the 370 limbs, 32 had healed ulcer (class 5) or active ulcer (class 6). Overall reflux in the superficial venous systm was found in 28 limbs (87.5%) and solitary superficial vein incompetence was detected in 13 (40.6%). Reflux extended throughout the length of the lesser and greater saphenous veins and retrograde peak velocity was greater than 30 cm/sec in these limbs. Reflux in perforating veins was detected in 14 limbs (43.8%). Deep vein incompetence was found in 12 limbs (37.5%) with concomitant superficial and perforating vein reflux. Isolated perforating and deep vein incompetence was detected in only one case.

The operations done included selective stripping of the lesser saphenous vein, high ligation of the lesser and greater saphenous veins, subfascial ligation of perforating veins, and compression sclerotherapy for varicose tributary veins. Clinical symptomatic improvement was significant following surgery. The active ulcers healed spontaneously within one month and the combined deep vein incompetence was improved by superficial ablation and subfascial ligation of the perforating veins.

In conclusion, patients with primary venous ulceration have varying degrees of deep, superficial, and perforator valvular incompetence. Surgical correction of venous insufficiency should be directed at superficial reflux in patients with concomitant superficial and deep vein incompetence. It has been proven and described by many well-known experts that after saphenous vein stripping combined with subfascial ligation of perforating veins, reflux was abolished in the deep veins. An explanation for this phenomenon is the overload theory or the increased flow produced by the saphenous vein return through perforating veins leading to dilation and incompetence of the deep venous valvular system.

Color duplex ultrasound is very useful in identifying the distribution and extent of reflux in patients with primary venous ulceration. A retrograde peak velocity exceeding 30 cm/sec with reflux throughout the vein length is a risk factor for venous ulceration when isolated superficial vein incompetence alone is present.

In a commentary following this paper, Bergan summarizes the most important contributions of this study. ivdfacs2




MINI ABSTRACTS
John J. Bergan, M.D.
Items of Interest Which Have Crossed the Editor's Desk
(Provided for reference purposes and general interest)


Meta-analysis of Hyperhomocysteinemia as a Risk Factor for Venous Thromboembolic Disease
Ray JG.
Arch Intern Med 1998; 158:2101-06

The presence of hyperhomocysteinemia is a significant risk factor for venous thromboembolic disease. This is most significant in patients under 60.


Massive Inferior Vena Cava Thrombosis Associated to Protein C Deficiency: Report of One Case.
Duclos JH, Castro JG, Cofre' PL, Saiz XB
Rev MÈd Chile 1997; 125:451-56

The authors report a case of an 18-year-old man with hereditary protein C deficiency and massive caval thrombosis treated by lytic therapy. The article makes the point of coagulopathies being responsible for unusual forms of venous thrombosis.


Prophylaxis of Venous Thromboembolism: Clinical Review
Verstraete M
Br Med J 1997; 314;123-25

This recognized authority presents a nicely balanced view of the current state of deep venous thrombosis prophylaxis.