Surgery of venous valve

Reviews in Vascular Medicine 1 (2013) 15–23

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Reviews in Vascular Medicine journal homepage: www.elsevier.com/locate/rvm

Review

Surgery of venous valve Alberto Caggiati a,n, Lorenza Caggiati b a b

Department of Anatomy, University Sapienza of Rome, Italy Villa Mafalda Hospital, Rome, Italy

a r t i c l e i n f o

abstract

Article history: Received 11 February 2013 Accepted 19 February 2013 Available online 21 March 2013

Main techniques proposed to restore venous competency in deep and superficial veins are reported. These include creation of ‘‘neovalves’’, valve reparation, and implantation of prosthetic valves. & 2013 Elsevier B.V. All rights reserved.

Contents Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Techniques for restoring VV function and venous competence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Neovalves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Internal valvuloplasty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 External valvuloplasty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Technical variations of external valvuloplasty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Valve plication techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 External VV banding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Transplantation of valve-bearing venous segments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Axillary vein autotransplantation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Axial transposition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Prosthetic valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Artificial valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Cryopreserved venous valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Valve substitutes implanted by a transcatheter technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Addenda: studies on biology and hemodynamic of prosthetic VV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Hemodynamics of prosthetic VV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 The importance of valve orientation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 The role of the endothelium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Introduction Chronic venous insufficiency (CVI) of the lower extremities is a common medical problem related to venous hypertension. The most common cause of venous hypertension is reflux by Venous Valve (VV) incompetence. Less commonly, reflux can be combined with venous obstruction. Clinical symptoms of CVI range from minor varicosities or mild edema, to lipodermatosclerosis and ulceration

n

Corresponding author. Tel.: þ39 06 49918114; fax: þ 39 06 49918081. E-mail address: [email protected] (A. Caggiati).

2212-0211/$ - see front matter & 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.rvm.2013.02.002

(Chronic Venous Disease, CVD). They depend on the extent of venous involvement and the degree of valve incompetence. Valve incompetence can be either primary or secondary. The primary (idiopathic) valve incompetence is thought to be related to structural abnormalities of the VV itself, or to an abnormally distensible venous wall. Secondary VV incompetence follows thrombosis and is caused by destruction of the leaflets secondary to the endovenous scarring of the inflammatory process. Aplasia of VV is an additional but rare cause of reflux. Legs with superficial VV insufficiency routinely undergo surgical extirpation of varicose veins or physical or chemical ablation. In turn, treatment of CVD legs is currently conservative and

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based upon palliative compression techniques. Even if elastic stockings or rigid bandages make CVD symptoms more tolerable, a high level of non-compliance is a major limiting factor resulting in their failure to obtain and maintain good clinical results. It is since the mid of twentieth Century that surgical techniques to restore VV function have been experimentally evaluated or, less frequently, applied in CVD patients. It was in 1953 that Eisemann and Malette created valve-like structures by gathering folds at two sites of the venous wall opposite each other [1]. One year later, Warren and Thayer published their technique of saphenopopliteal bypass to restore both canalization and competence in post-thrombotic legs [2]. For the same purpose, Palma and Esperon proposed in 1960 vein transplantation [3]. In 1965, McLachlin and colleagues implanted valve-bearing allografts in the femoral vein of dogs [4]. Finally, it was in 1968 that Kistner popularized a technique to restore VV function by direct surgery [5] and Psathakis a ‘‘substitute valve’’ [6]. Surprisingly, all the techniques proposed in the following fifty years to restore venous competence are based upon the principles of these Pioneers. The purpose of this review is to summarize technical developments in the field of VV construction, restoration, transplantation or substitution with artificial ones.

Techniques for restoring VV function and venous competence Very numerous procedures were proposed to restore venous competence and VV function (Table 1). They differ greatly with regard of techniques and materials. In order to facilitate exposition and reading, main techniques used or proposed for restoring VV function have been here designated in:

1) Valve creation a. Neovalves 2) Valve Reparation a. b. c. d.

Internal valvuloplasty External valvuloplasty VV plication VV banding

3) Valve substitution a. Transplantation of valve-bearing venous segments b. Axial transposition c. Prosthetic valves 4) Laboratory investigations on biology and hemodynamic of prosthetic VV.

Table 1 Acronyms used in the text. CVI: Chronic Venous Insufficiency CVD: Chronic Venous Disease VV: venous Valve IJV: Internal jugular vein EJV: External jugular Vein IVC: Inferior vena cava GSV: Great Saphenous Vein SFJ: Sapheno Femoral Junction FV: Femoral Vein

Neovalves In order to abolish reflux, Eisemann in 1953 ‘‘created’’ new valves in the native vein by arranging an intimal flap as a pouch [1]. This early experience gave no good results but Eisemann’s idea was reconsidered in the last 25 years. In fact, it was in 1988 that Rosenbloom and colleagues, constructed VV in segments of canine external jugular veins by intimal separation, folding and suturing [7]. The newly created valves were interposed in the canine femoral vein. In 1991, Wilson and colleagues, proposed a technique of creating neovalves in the femoral vein of dogs by intussusceptions of the vein into itself [8]. The bicuspid valve was made by two sutures placed at 1801 to hold the inner vein wall in correct position. Short-term patency was good with competency rate of 90–100%, but hemodynamic results were not as fair as in the case of native valves. Half a Century after Eisemann, Corcos and colleagues reconstructed a monocuspid popliteal valve by intimal flap in patient afflicted with secondary valveless deep venous insufficiency of the lower limbs [9]. In 2006, Maleti and Lugli proposed a technique to create an antireflux mechanism in patients affected by post-thrombotic syndrome or valve agenesis [10]. After a carefully preoperative Duplex evaluation of crural valves, the femoral vein is exposed and venotomized to dissect the intima and to raise an intimal flap. A monocuspid or a bicuspid valve can be created in this fashion. The depth of dissection varied according to the wall thickness whereas the width of flap was assessed in order to prevent valve prolapse. This technique was further refined in 2009 when Lugli and Maleti proposed to stitch the free edge of the flap to the vein wall so to prevent reattachment of the flap to the original vein wall [11]. Postoperative duplex scan and air plethysmography measurements showed a significant improvement, as well as ulcer healing and patency rate. However, the Authors warned to exclude patients with severe limited ambulation, thrombophilia, bleeding diathesis, or other severe comorbidity. Finally, Opie and colleagues described in 2008 a similar technique to construct monocusp valves when unusable valves were encountered at the level of the Common Femoral Vein [12]. Fourteen monocuspid VV were reconstructed in 11 patients. Long-term follow-up showed that the monocusp valves remained competent at four years, with significant improvement of CEAP and VEINES scores.

Internal valvuloplasty The purpose of valvuloplasties is to regain VV competence by surgical correction of elongated leaflets. They all are based upon the original observation made by Kistner who discriminated two forms of valvular incompetence: (1) incompetence due to extensive valve damaging and (2) incompetence due to elongation of the cusps [5]. For cases with elongated cusps Kistner proposed in 1968 the first valvuloplasty procedure which required venous opening (internal valvuloplasty). In fact, a longitudinal venotomy was necessary to expose the redundant valve cusps and to suture them to the vein wall (transcommissural approach). This technique was modified in 1983 by Raju who advocated a supravalvular (supracommissural) transverse venotomy [13], and finally by Sottiurai who utilized a hybrid T-shaped supravalvular (supraT_commissural) incision [14]. Despite the different approach to expose the valve leaflets, they all were based upon suture repair of elongated but healthy cusp leaflets. As a consequence, the early and long-term results have been similar: the primary valve repair has remained competent for 8 to 15 years in 60% to 73% of the cases, and the

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patients experienced good to excellent results in nearly all of those that remain competent [15–17]. The more recent technique of internal valvuloplasty was proposed by Tripathi and Ktenidis in 2001 [18]. After exact commissure identification, a transverse venotomy involving half the circumference is made from the axis of the center of one commissure to the other, one centimeter above and below the target valve. The anterior ends of the two transverse venotomies are connected by a longitudinal venotomy along the more anterior of the two commissures. This creates a trapdoor at the level of the VV.

External valvuloplasty External valvuloplasty was introduced by Kistner in 1990 [19]. While internal valvuloplasties correct the valve cusps without considering the commissural angles, the external valvuloplasty corrects the commissural angle without considering the valve cusps. In fact, the first step consisted of an accurate adventitial dissection to clearly identify VV leaflet insertions. Then, an external row of sutures is placed along the diverging margins of the valve cusp, on both sides of the vein (transmural commissural valvuloplasty). In fact, the commissural angle in reflexive valves is widened than in competent ones [8]. The interrupted sutures are carried inferiorly until the valve becomes competent by strip testing. The technique for external valvuloplasty was refined in 2000, when Raju and colleagues described a variation of closed external venous valve repair defined as ‘‘transcommissural valvuloplasty’’ which differs from transmural valvuloplasty by the use of a transluminal suture [20]. The advantage of transcommissural valvuloplasty is that it corrects both the redundant valve cusps as well as commissural angles. After adventitial dissection and identification of valve station, a through and through transluminal resuspension suture is passed obliquely across the inverted ‘‘V’’, traversing both the cusps near their attachment to the wall. Involvement of both the valve cusps is evident by puckering of the valve attachment lines. Further two to four more interrupted stitches are placed distally, each of them being less deep and less oblique. The last stitch is at one to two millimeters beyond the point of maximum bulge at the valve station. Competency rates of transcommissural valvuloplasty reported were comparable to those of internal valvuloplasty. Advantages over the internal repair are that venotomy is not required, repair can be extended to small-caliber veins, and multiple valve stations can be repaired in a single stage. Technical variations of external valvuloplasty Angioscopy facilitates to ascertain VV to be treated with external repair and to control the efficacy of the procedure under visual control with the valves under pressure. Angioscopically assisted valvuloplasty was introduced in 1991 by Gloviczki and colleagues [21]. After navigation under vision to evaluate valvular competence of the femoral tract, they placed polypropylene sutures from outside to inside the lumen laterally to the site of insertion of each valve. The elongated valves are gradually shortened and their competence checked by infusion of irrigation fluid via the angioscope. In addition, an external PTFE cuff was placed around the site of repair to prevent venous dilatation. In 1996, Lermusiaux and De Forges associated angioscopy-assisted venous valvuloplasty of the femoral vein with its external wrapping with a segment of polytetrafluoroethylene prosthesis, and contemporary stripping of incompetent superficial veins plus subfascial ligation of perforating veins [22]. In 1997 Hoshino and colleagues performed

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external valvuloplasty in both femoral and saphenous veins under direct vision using angioscopy by means of different procedures: (1) total plication of the dilated vein annulus by running a suture around the vein; (2) plication by placing an autogenous femorofascial band; (3) a direct suture of valve commissure including the leading edge of the cusp from the outside vein wall using horizontal mattress suture with pledgets. [23] The necessity of associating external valvuloplasty to varicose vein ablation was stressed in 2002 by Sakuda and colleagues, [24]. Their results pointed to the functional and clinical usefulness of femoral valvuloplasty performed simultaneously with varicose vein surgery in patients with moderate to severe deep venous reflux. The utility of contemporary valvuloplasty and surgery of superficial varicose veins was confirmed in 2006 by Wang and colleagues. They compared long-term results of surgery of superficial veins alone and associated to external valvuloplasty in limbs with primary CVD [25]. External valvuloplasty of the femoral vein combined with surgical repair of the superficial venous system improved the hemodynamic status of the lower limbs, restored valvular function more effectively, and achieved better outcomes than surgical repair of the superficial venous system alone. Finally, Us and colleagues re-proposed in 2007, to combine transcommissural external valvuloplasty with external banding of the venous segment hosting the repaired valve [26]. The Authors reported that addition of external banding provides lesser incidences of ulcer recurrence and valve incompetence.

Valve plication techniques Historically, the external valve repair proposed by Psathakis in 1968 with the gracilis muscle [6] and in 1984 with a silicone tendon [27], could be considered the first attempts of placation technique to restore VV function. The first to introduce the concept of VV restorative plication was Belcaro in 1989. He proposed plication of the terminal saphena to treat incompetence of the SFJ [28]. In 1993, he described placation of the femoral vein, too. In this case Belcaro suggested to limit plication to the anterior side of the incompetent femoral vein (limited anterior plication, LAP) [29]. This technique did not need venotomy and was based upon transmural suturing through the valve attachment lines. Limited anterior plication involves continuous mattress suturing from a point 3 to 4 mm proximal to the valve cusp insertion lines up to the angle of valve cusp insertion. This results in narrowing of the commissural angles, thus making the valves competent. The LAP was considered an alternative to the standard external valvuloplasty in cases of moderate incompetence when valve cusps are present and functional and incompetence is mainly due to relative enlargement of the vein diameter [30]. The procedure was aimed to reduce the amount of vein dissection and the risk of progressive venous dilatation, frequent in some cases of valvuloplasty. In 2001, Nishibe and colleagues proposed angioscopy-assisted anterior valve sinus plication and demonstrated that this technique gives early good clinical and hemodynamic improvement in patients with primary deep venous insufficiency [31].

External VV banding The purpose of these techniques is to restore competence of dilated venous segments with healty valve leaflets. These techniques are based on supporting the vein wall from outside reducing their caliber, so to restore leaflets function and preventing further dilation.

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The first to adopt an external banding technique to restore valvular funcion was Hallberg who, in 1972, proposed to sheath the region of incompetent valves of deep veins with a plastic tube [32]. Despite first results were encouraging, then Hallberg himself stressed this technique could not recommended for routine application. In 1988, Jessup and Lane developed an implantable device called Venocuff to restore venous valve competence by reducing the vein circumference [33]. The device was implanted in the jugular vein of sheeps and the efficacy evaluated by pressure measurements. Positive results of this technique in subjects with primitive and post-phlebitic valvular insufficiency were reported in 1998 by Guarnera and colleagues who used a Dacron sleeve of a Venocuff device. [34] Similar results were reported in 1999 by Akesson and colleagues [35]. In 2003, Lane and colleagues reported the efficacy of contemporary stenting of multiple valves and stated that the number of stents implanted was statistically associated with an increased number of ulcers healing [36]. The Authors concluded that multiple deep venous valve repairs are appropriate and the best form of treatment for specifically selected individuals with primary deep venous incompetence. External banding was also proposed for treatment of varicose veins. In 1997, Corcos and colleagues proposed external banding of the terminal saphena by a thin nylon reinforced elastic silicone layer, applied by manual suture [37]. They noted better results in limbs with early disease, with 18% of reflux recurrency after operation. In 1999 Belcaro and colleagues adopted an expanded polytetrafluoroethylene (ePTFE) external valve support to be placed at the sapheno-femoral junction (SFJ). [38] Results of 0 years follow up were reported in 2011 and compared with those from subjects underwent conventional treatment (stripping). Belcaro and colleagues concluded that external PTFE support was well tolerated with lesser occurrence of new incompetent sites as well of skin changes. In 2007, Lane and colleagues adopted specifically designed Dacron reinforced silicone to band the GSV at the level of the subterminal valve [39,40]. The comparative evaluation of long term results of external valvular stenting and stripping of the GSV demonstrated that in patients at an early stage of the disease process where venous valve structure is essentially intact, EVS is a physiological alternative to stripping [41].

Transplantation of valve-bearing venous segments Firstly described by Taheri in 1982 [42], the purpose of these techniques is to transpose a competent valve-bearing venous segment into the axial deep venous system. They are mainly indicated in cases of deep venous reflux with destroyed valves. Axillary vein autotransplantation In 1982, Taheri and colleagues proposed the transplantation of a 2–3 cm segment of the axillary vein containing a competent valve (or a reparable one) in the femoral vein [42]. The segment of the femoral vein containing the incompetent valve was removed. If the axillary valve is incompetent, a bench repair by transcommissural external valvuloplasty technique was done before anastomosis. The proximal anastomosis of the femoral with the axillary vein segment was performed by interrupted sutures. Proximal anastomosis was done earlier than the distal one, in order to control valvular competence and to obtain distension and lengthening of the transposed segment (to facilitate distal anastomosis). In order to prevent possible dilatation of the grafted segment, Raju recommended in 1988 to sheat the grafted segment with an external PTFE sleeve, secured by adventitial stitches [43]. Both Authors noted an

unacceptable high incidence of postoperative occlusions. For this, in 1999, Raju recommended to carefully remove intraluminal synechiae thus creating a sizeable lumen for proper anastomosis [44]. In this study Raju also reviewed 102 procedures of axillary vein transfer concluding that this procedure is safe, effective, and durable in patients with trabeculated veins and severe forms of postthrombotic syndrome. In 1995, Bry and colleagues described the implantation of a valvulated segment of the axillary vein in the popliteal, reporting optimal clinical results [45]. However, a recent (2011) analysis of cases underwent axillary-to-popliteal valve transfer has affirmed that, despite initial technical and symptomatic success with venous valve transplantation, there is a poor long-term valve competency rate and symptomatic control [46].

Axial transposition These techniques were introduced by Cardon and colleagues in 1999 [47]. They are based upon reimplantation of an incompetent vein distally to a competent valve of another vein. Prerequisite for this procedure is that at least a single axial venous valve in the groin area is competent. Cardon and colleagues reimplanted incompetent femoral distal to a competent valve of the deep femoral vein or of the great saphenous [48]. They concluded that transposition using the ipsilateral greater saphenous vein is safe and effective with good mid-term results, especially for pain [47]. In 2001, Yamaki and colleagues, proposed to combine valvuloplasty of the subterminal valve with axial transposition of a competent tributary vein for the treatment of GSV incompetence [49]. They demonstrated that valvuloplasty combined with axial transposition of a competent tributary vein gives a better result than valvuloplasty alone at the 18-month follow-up [50]. A competent valve in this location can be expected to improve local haemodynamics. In 2009 a refinement of this technique was proposed by the same group for patients with isolated great saphenous vein incompetence [51]. After valvuloplasty, a competent tributary vein was cut 1.5 cm distal to its insertion point on the GSV. The transected vein was anastomosed end-to-side to the GSV, which was ligated between the tributary insertion site and the anastomosis. The Authors stated that this procedure improves venous function, resolves varicose veins at 5-years follow-up as well as preserving the GSV for future grafting. Similar positive results were obtained in limbs with deep venous incompetence by Rosales and colleagues, who associated external valvuloplasty to vein transposition [52]. The Authors recommended performing plasty at popliteal level, due to a longer recurrence-free period.

Prosthetic valves First attempt to implant prosthetic valves dates back to 1965, when McLachlin and colleagues, implanted valved vein allografts into the femoral veins of 14 dogs [5]. At 1-month follow up, only 1 graft was patent. In the following fifty years, several prosthetic valves made with different materials have been proposed, as well multiple approaches to valve substitution were tried experimentally. (Table 2). However, majority of the attempts of prosthetic venous valve repair have not shown good results. For this, in order to prevent VV failure or thrombosis, laboratory investigations on prosthetic VV biology and hemodynamic have been launched. Artificial valves Twenty years after Lachlin’ initial experience, Hill and colleagues developed prosthetic valves they produced from two different materials: Pellethane valves were produced by a dip-casting process

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Table 2 Surgery of venous valve. Technical variants Neovalve

Intimal folding Intussusception Monocuspid Bicuspid

Eisemann Wilson Corcos Maleti

1953 1991 2003 2006

Valvuloplasty

Internal

Transcommissural Supracomisural Trapdoor

Kistner Raju Tripathi

1968 1983 2001

External

Transmural Transcommissural Variations or associaion

Kistner Raju Glovizki Hoshino

1990 2000 1991 1997

Plication

VV of deep veins Terminal valve at SFJ Angioscopically assisted LAP ‘‘Substitute’’ valve

Belcaro Belcaro Nishibe Psathakis

1990 1989 2001 1984

External banding

Deep Deep Deep Deep SFJ SFJ SFJ

Plastic tube Venocuff Dacron sleeve Multiple stenting Nylon cuff PTFE cuff Dacron cuff

Hallberg Jessup Guarnera Lane Corcos Belcaro Lane

1972 1988 1998 2003 1997 1999 2007

Autotransplantation of Valve Bearing Segment

Axillary Axillary Axillary Axillary

þ bench repair þ PTFE external banding þ endophlebectomy

Taheri Raju Raju Bry

1982 1988 1999 1995

Vein Transposition

Femoral reimplant Femoral reimplant Saphenous reimplant

Cardon Rosales Yamaki

1999 2008 2001

veins veins veins veins

to to to to

femoral femoral femoral popliteal

whereas human umbilical vein valves were produced by a fixation process [53]. The valves were evaluated as implants within the external jugular veins of 10 research dogs. Each animal was implanted with one Pellethane valve in one external jugular vein and one umbilical vein venous valve in the contralateral jugular vein. Poor results were obtained with both techniques. Again in 1988, Taheri and colleagues developed sutureless prosthetic VV. These were constructed of platinum and titanium. Five on ten valves were still patent fourteen to eighteen months post-insertion into the femoral vein or vena cava of mongrel dogs [54]. The same group in 1995 developed a platinum or pyrite carbon-covered titanium bileaflet valve that was implanted into canine femoral veins [55]. Valves were patent and competent at 3 months, but two of the valves migrated or were misoriented leading to failure. Within two years, all canines developed symptoms of CVI due to intimal hyperplasia. In 2006, Sathe and Ku proposed a synthetic venous valve, which is composed of a clinically approved polymer [56] (Table 3). Cryopreserved venous valves Cryopreserved valves or cryopreserved valve-bearing short venous segments have been used to restore vein competence in humans and in animals. Cryopreserved VV could be from animals of the same or different species, as well as from donor veins different from the recipient ones. In 1997, Burkhart and colleagues transplanted cryopreserved valve-bearing allograft to the femoral vein of a canine insufficiency model. A distal arteriovenous fistula was also performed to increase the efficacy and long-term patency of the transplanted segment [57]. Two years later, clinical results obtained in a series of 10 patients with post-thrombotic syndrome, were reported by Dalsing and colleagues [58]. They concluded that in patients with

þ valvuloplasty þ valvuloplasty

few remaining therapeutic options, cryopreserved VV implantation can achieve a 6-month assisted patency and competency rate of 78% and 67%, respectively, with an improved clinical outcome. In 2002, Garcia-Rinaldi and colleagues implanted cryopreserved allograft monocusp patches made from cadaveric pulmonary arteries to correct non-thrombotic valvular insufficiency of the common femoral vein in patients with chronic venous ulcers [59]. They noted that ulcers remained healed when the prostheses remained competent. No implanted monocusp patch developed clots. In 2003, Neglen and Raju evaluated the immediate and short-term outcome of inserted cryopreserved vein valve allografts [60]. The most common insertion site was the femoral or popliteal vein and contemporary valvuloplasty was frequently necessary. They concluded that cryovalve insertion is associated with high morbidity (48%), high occlusion rate (59%), poor cumulative midterm rate of patent graft with competent valve (27%), and poor clinical results. They recommended cryovalve insertion should not be used as a primary technique for valve reconstruction, and it is questionable whether it is useful even in patients in whom autologous reconstruction techniques have been exhausted.

Valve substitutes implanted by a transcatheter technique Valve substitutes can be implanted by a transcatheter technique. These valves consisted of single, double or triple cusp leaflets made of synthetic or biological materials attached to a carrier or frame. Historically, the first to propose the implantation of a percutaneous artificial venous valve for CDVI patients for whom surgical treatment had failed was Dotter in 1981 [61]. Then, numerous techniques of percutaneous implantation of valve prosthesis were proposed. They differed for the material used

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Table 3 Valvular prosthesis. SYNTHETIC VV

Vein allografts in canine femoral V. Pellethane Thermoplastic elastomere in dog EJV Human umbilical VV in dog EJV Platinumþtitanium VV in canine IVC or FV Polyurethaneþ Z-stent in swine IVC Carbon-covered Platinum þtitanium in canine FV Polymer

A A A A A A L

S E S S E S –

McLachlin Hill Hill Taheri Uflacker Taheri Ku

1965 1985 1985 1988 1995 1995 2006

CRYOPRESERVED VV

Cryopreserved VV in canine FVþ AV fistula Cryopreserved VV in human FV þ AV fistula Cryopreserved VV from human pulmonary vessels in human FV CRYOPRESERVED VV da cosa in human femoral and poplitealþ valvuloplasty

L H H H

S S CTR CTR

Burkhart Dalsing Garcia-Rinaldi Neglen

1997 1999 2003 2003

BIOPROSTHETIC VV

Dog EJV in homologous counterlateral IJV Homologous VV From goat EJVþ Wallstent Small Intestine Submucosa (SIS) þ Z-stent Fixed bovine EJV VV þnitinol stent Bovine EJV þnitinol in porcine iliac vein SISþ nitinol square stent Autogenous VV þnitinol stent

A A A A A AþH A, H

E E E E E E E

Dalsing Ofenloch Thorpe Gomez de Borst Pavcnik Phillips

1996 1997 2000 2000 2003 2002/2006 2012

A: Animal experiment. H: implanted in Humans. S: surgical implantation of prosthetic valve. E: endovascular implantation of prosthetic valves.

(synthetic or biomaterials), the design for the prosthesis, its treatment and, finally, the carrier used for valve attachment. In 1993, Uflacker developed an artificial monocusp VV, which consisted of a thin polyether urethane membrane inside a single body Z-stent [62]. The valves were inserted percutaneously into swine inferior vena cava. A Z-stent was also used in 1996 by Dalsing and colleagues to support a segment of dog external jugular vein transplanted in the counterlateral vein [63]. Good results in term of patency were noted at 4 weeks follow up. In 1997, Ofenloch and colleagues proposed to endoscopically harvest a valve-containing segment of goat external jugular vein [64]. This segment was then sutured inside a Wallstent and finally deployed through a venotomy into the contralateral external jugular vein. Thorpe and colleagues, in 2000 experimentally investigated a bicuspid venous valve made of the porcine small intestinal submucosa (SIS) mounted in a double body Z-stent [65]. They reported promising in vitro and short-term results in the porcine model. In 2000, Gomez-Jorge et al. developed a bioprosthetic VV consisting of a trimmed and gluteraldhyde-fixed segment of bovine external jugular vein fixed by suture on a selfexpanding nitinol stent [66]. These bioprosthetic devices were introduced percutaneously and deployed into Inferior Vena Cava or iliac vein of 11 pigs. In 2003, de Borst, and colleagues adopted a memorycoded nitinol frame to deploy gluteraldheide-fixed bovine jugular valves in porcine iliac veins [67]. They noted oral anticoagulation was necessary to prevent valve thrombosis. Starting from 2002, Pavcnik and his group developed three types of bioprosthetic venous valves (BVV 1,2,3) consisting of a small leaflet of an acellular, non-immunogenic, biodegradable, xenogenic, collagen-based biomaterial derived from the submucosal layer of porcine small intestine (SIS) anchored to a nitinol square stent [68–70]. The role of the collagen sheet was to provide a temporary scaffold for cellular colonization. The device featured sinuses and barbs for vascular wall anchoring and was designed to be deployable via catheter. The nitinol stent was designed to prevent contact of leaflets with the venous wall and was furnished of barbs for valve stabilization. BVV have been implanted in ovine jugular veins and in a small number of CVD legs [70]. Although the previously described efforts by Pavcnik et al. [71] have shown favorable in vivo results in the short-term, a human feasibility study revealed that occlusion occurred in four of fifteen valves at 12-month follow-up. Additionally, three

oversized valves opened too much resulting in leaflet-to-wall attachment and four devices exhibited undesirable leaflet pliability from adverse healing. Hence, the potential for clinical application of this bioprosthetic venous valve remains uncertain. In 2012, Phillips and colleagues, reported about their experience with a new Nitinol stent which would facilitate the autogenous transfer of VV [72]. The results from an in-vivo study in sheep were encouraging. For this, a modification of this protocol has recently commenced human trials. A thorough review of the literature focusing on technical aspects of valve stent design was performed in 2012 by de Borst and Moll [73]. They found most valve models reviewed were for the most part implanted safely and accurately, with good shortterm patency and competency. They assumed that valve configuration determines long-term results. At any case, results of experimental studies are generally good at short-term, whereas long-term patency or competence very poor (disappointing). Moreover, they noted that, unfortunately, very few studies were performed in humans.

Addenda: studies on biology and hemodynamic of prosthetic VV More important limiting factor in the use of prosthetic valves as compared to native ones are valve competence and thrombosis of the substituted, transplanted or created valve. A few studies focused biological and hemodynamic aspects of prosthetic valves correlated to their efficacy and to the onset of thrombosis. Hemodynamics of prosthetic VV In 1988, Rosenbloom and colleagues, evaluated the competence of neovalves harvested from canine jugular obtained by intimal folding and suturing. Neovalves were removed at different intervals and evaluated for their competency. The Authors stressed that the ability to remain competent at high pressures may give this valve an advantage over the repaired, transposed, or transplanted native venous valve in the treatment of chronic venous valvular insufficiency. In the same year, Kava and colleagues evaluated the patency and valvular function of transplanted femoral vein grafts in mongrel dogs after storage in glutaraldehyde [74].

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In vitro experiments were conducted by Wang and colleagues in 1992 by mounting bovine jugular valves in straight, tapered and curved conduits to determine that different pulse pressure thresholds necessary to ‘‘reestablish the closure-opening operation mode’’ for each conduit geometry [75]. In 1993 Delaria and colleagues comparatively evaluated fresh and glutaraldehyde fixed bovine jugular vein conduits in an in vitro flow system [76]. Better results were obtained in valves underwent fixation possibly because fixation theoretically renders biocompatible and non-thrombogenic tissue. In 2008, Oberdier and Rittgers reported the results of sophisticated in-vitro evaluations of an innovative prosthetic VV [77]. This consisted of a combination of the solid frame fabricated with stereolithography and flexible leaflet. A complex series of laboratory evaluations lead the Authors to affirm that this kind of prosthetic venous valve has the potential to reestablish normal antegrade circulation. No further development of this device is reported. In 2011, Moriyama and colleagues evaluated hydrodynamic characteristic of prosthetic venous valves produced by electrospinning to be inserted after implantation on an opposite stent [78]. These valves consisted of polyurethane fiber scaffolds attached to a cobalt-chromium stent. The antegrade flow, effect of ankle flexion, and stagnation zones around the valve leaflets were evaluated in two different valve-leaflet configurations were compared: biomimetic and open. According with experimental findings, the biomimetic one would result clinically suitable for percutaneous treatment of CVI. The importance of valve orientation The importance of valve orientation was also evaluated. In 2005, Pavcnik and colleagues, evaluated the possible role of spatial orientation of bioprosthetic venous valves in 12 sheep [79]. They implanted second generation BVV in the jugular vein of sheep at different angulations with respect of that of the natural valve present at that level. Valve function was evaluated by venography whereas structural changes by histology. The Authors concluded that the spatial orientation of a prosthetic valve is determinant to preserve VV function and patency. The role of the endothelium In 2003 Teebken and colleagues, implanted decellularized allograft VV mounted on Z-type stents into the jugular veins of six sheep, unaided by anticoagulation [80]. All these thrombosed by week 6. In turn, repopulation of similar allografts with donor smooth muscle and endothelial cells had improved results because, at 12 weeks, 75% of the repopulated allografts were patent and competent without anticoagulation. These studies firstly indicated that early cellularization of bioprosthetic valves may prevent thrombosis and the fibrosis of the implanted valves. In 2009, the same group in vitro evaluated the use of a decellularised scaffold and its re-endothelialisation in order to create human vascular substitutes containing venous valves [81]. Valve-bearing segments were from human allogeneic great saphenous veins that were decellularised using sodium deoxycholic acid and Dnase. Then the scaffolds were re-seeded with human venous endothelial cells enzymatically harvested from the GSV by a 3D bioreactor. In 2012, Jones and colleagues, used endothelial progenitor outgrowth cells (EOCs) from ovine blood as a source of in vitro autologous seeding for SIS endothelialization [82]. Retention of the endothelial monolayer was evaluated with immunofluorescent staining and histologic analysis. Immunofluorescent staining of EOCs on the valves after in vitro seeding revealed a confluent monolayer on each side of the valve. The Authors concluded that

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EOCs are a promising cell source for autologous endothelialization of bioprosthetic valves for the treatment of CDVI

Conclusions Over the past 30 years multiple methods have been developed to surgically restore valvular function but only few of them were applied in humans. Improved venous hemodynamics and valve competency have been demonstrated. However, the majority of these valve studies await confirmation by other investigators over extended periods. In fact, lack in uniformity in surgical approach, patient selection and reporting of results made difficult to comparatively evaluate their efficacy and safety. Guidelines or consensus documents establishing which patients are to be considered for VV surgery as well criteria to evaluate clinical results are auspicable. At any case, a general agreement is in literature on the following points: deep vein valve repair is considered a secondstage operation when lesser invasive therapies have failed. Venous obstruction, if present, should be treated earlier than reflux. Superficial venous reflux is treated earlier than deep one, but it has been also suggested to treat them concomitantly when possible. Surgery to correct deep venous insufficiency (DVI) remains an appropriate option in selected patients. Currently, creation of new VV and VV external repair, have proven more promising. References [1] Eisemann B, Malette W. An operation technique for the construction of venous valves. Surgery, gynecology & Obstetrics 1953;97:726–31. [2] Warren R, Thayer TR. Transplantation of the saphenous vein for postphlebitic stasis. Surgery 1954;35:867–76. [3] Palma EC, Esperon R. Vein transplants and grafts in surgical treatment of the postphlebitic syndrome. Journal of Cardiovascular Surgery 1960;1:94–107. [4] McLachlin AD, Carroll SE, Meads GE, Amacher AL. Valve replacement in the recanalized incompetent superficial femoral vein in dogs. Annals of Surgery 1965;162:446–52. [5] Kistner RL. Surgical repair of a venous valve. Straub Clinic Proceedings 1968;34:41–3. [6] Psathakis MN. Has the substitute valve at the popliteal vein solved the problem of venous insufficiency of the lower extremity? Journal of Cardiovascular Surgery 1968;9:64–70. [7] Rosenbloom MS, Schuler JJ, Bishara RA, Ronan SG, Flanigan DP. Early experimental experience with a surgically created, totally autogenous venous valve: a preliminary report. Journal of Vascular Surgery 1988;7:642–6. [8] Wilson NM, Rutt DL, Browse NL. In situ venous valve construction. British Journal of Surgery 1991;78(5):595–600. [9] Corcos L, Peruzzi G, Procacci T, Spina T, Cavina C, De Anna D. A new autologous venous valve by intimal flap. One case report. Minerva Cardioangiologica 2003;51:395–404. [10] Maleti O, Lugli M. Neovalve construction in postthrombotic syndrome. Journal of Vascular Surgery 2006;43:794–9. [11] Lugli M, Guerzoni S, Garofalo M, Smedile G, Maleti O. Neovalve construction in deep venous incompetence. Journal of Vascular Surgery 2009;49:156–62. [12] Opie JC, Izdebski T, Payne DN, Opie SR. Monocusp—novel common femoral vein monocusp surgery uncorrectable chronic venous insufficiency with aplastic/dysplastic valves. Phlebology 2008;23:158–71. [13] Raju S. Venous insufficiency of the lower limb and stasis ulceration. Annals of Surgery 1983;197:688–97. [14] Sottiurai VS. Technique in direct venous valvuloplasty. Journal of Vascular Surgery 1988;8:646–8. [15] Kistner RL. Valve reconstruction for primary valve insufficency. In: Bergan JJ, Kistner RL, editors. Atlas of venous surgery. Philadelphia: WB Saunders; 1992. p. 125–30. [16] Raju S. Supravalvular incision for valve repair in primary valvular insufficency: method of Raju. In: Bergan JJ, Kistner RL, editors. Atlas of venous surgery. Philadelphia: WB Saunders; 1992. p. 135–7. [17] Sottiurai VS. Supravalvular incision for valve repair in primary valvular insufficiency: method of Sottiurai. In: Bergan JJ, Kistner RL, editors. Atlas of venous surgery. Philadelphia: WB. Saunders; 1992. p. 137–44. [18] Tripathi R, Ktenidis KD. Trapdoor internal valvuloplasty—a new technique for primary deep vein valvular incompetence. European Journal of Vascular and Endovascular Surgery 2001;22:86–9. [19] Kistner RL. Surgical technique of external venous valve repair. Straub Foundation Proceedings 1990;55:15–6.

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[81] Teebken OE, Puschmann C, Breitenbach I, Rohde B, Burgwitz K, Haverich A. Preclinical development of tissue-engineered vein valves and venous substitutes using re-endothelialised human vein matrix. European Journal of Vascular and Endovascular Surgery 2009;37(1):92–102. [82] Jones CM, Hinds MT, Pavcnik D. Retention of an autologous endothelial layer on a bioprosthetic valve for the treatment of chronic deep venous insufficiency. Journal of Vascular and Interventional Radiology 2012;23(5):697–703.