Emergency Vascular Surgery A Practical Guide - part 10

182 Chapter 15 General Principles of Vascular Surgical Technique In larger arteries such as the aorta, a Foley catheter of appropriate size can be used for the same pur-pose. Special catheters from different manufactur-ers are also available for occluding arteries. When balloons are used for proximal control they are easily dislocated and even blown out by the arte-rial pressure. This can be avoided by having an assistant manually support the catheter or by applying a vascular tape around the artery just proximal to the arteriotomy, thus preventing the balloon from being further dislocated distally. NOTE Never open a blood vessel without having proximal and distal control. 15.4.1 Proximal Endovascular Aortic Control Fig.15.4. A temporary vascular clamp is made by pull-ing a double vessel-loop through a piece of rubber tub-ing to make a snare around the vessel, which is locked by an ordinary clamp In certain situations, such as in scar tissue, thorough dissection of a vascular segment can be technically very challenging and should thus be avoided. Balloon occlusion can be a very good alternative for distal as well as temporary proxi-mal control. Control is, however, best achieved by surgical exposure and clamping of a more proxi-mal segment, while balloon occlusion is always an alternative for distal control. Embolectomy cathe-ters of adequate size connected to a three-way stopcock and a saline-filled syringe are used. In-spection of the open segment, under continuous evacuation of blood from the backbleeding branches with suction, allows identification of the orifice into which the catheter should be inserted. After insertion the balloon is insufflated until the backflow has ceased. The stopcock is closed, and the balloon is left in place to occlude the artery. It is important not to overinflate the balloon, which could damage the arterial wall. In analogy with a vascular clamp, the balloon should be insufflated just to the point when bleeding stops – no further. When available, this alternative is of great poten-tial importance for patients with severe intraab-dominal bleeding after rupture of aneurysms as well as traumatic vascular injuries. It is further described in Chapter 7 (p. 85). 15.5 Vascular Suture When vessels are sutured, the suture should in-clude all the layers of the vessel wall. The adventi-tia is the most important layer for the mechanical strength of the vascular wall. The adventitia should not be allowed to be interposed between the approximated edges of the arteriotomy be-cause that can disturb the healing process. This can be avoided by everting the edges to allow inti-ma-to-intima approximation. When vessels are being sutured, the needle’s point should be placed at a 90° angle against the vascular wall, and thereafter its circular shape is used to push it through the wall to avoid un-necessary tearing. It is important to place the needle from inside out, particularly on the downstream side of the vascular suture, in order to fasten and secure the intima, avoid splitting the wall layers, and avoid the risk of intimal dissection (Fig. 15.5). Arteriosclerotic arteries can be very hard and calcified, making penetration of the needle at an ideal site impossible. In such a situation it might 15.5 Vascular Suture 183 Fig.15.5. The needle should be directed 90° to the vessel wall. Always include the intima, especially on the downstream side, to avoid dissection of the distal intimal edge be necessary to penetrate the vascular wall with the needle and suture at a far distance from the intended suture row. Sometimes it is necessary to remove an extensive and hard arteriosclerotic plaque by a local thrombendarterectomy before the repair can be completed. Another important detail in suturing arteries is to tighten the suture satisfactorily; a suture that is too loose will cause leakage, and if it is too tight this will certainly lead to stenosis. The angle when pulling the suture should be 90° from the vascular wall to minimize the risk of tears in the vascular wall. Oozing in the suture row is best managed by tamponade with a sponge for 5–10 min or until bleeding stops. If extra hemostatic sutures are needed, a suture one size smaller than those in the suture row is recom-mended. If the result is unsatisfactory a local hemostatic agent can be applied. Simple suturing for minor traumatic injuries in arteries is demonstrated in Fig. 15.6. It is impor-tant to tie the suture with the artery clamped and not pulsating to get it properly adjusted. Fig. 15.6. aSimple cross-suture of an arterial puncture. b Simple sutures in a transverse arterial injury or arteri-otomy. cIf the artery is large (>10mm wide) a running suture can be used 184 Chapter 15 General Principles of Vascular Surgical Technique 15.5.1 Choice of Suture Material Vascular sutures are monofilament, synthetic, and double-armed. The needles are taper-pointed and have a variety of curvatures. Most vascular needles are larger than the suture to which they are at-tached. This can be a source of suture-line bleed-ing, which is best treated with local compression and hemostatic agents, but not with further su-tures. Recommendations for sutures are given in Table 15.1 below. Table15.1. Suture sizes for various vessel segments Vessel Suture size Aorta 3-0 to 4-0 Iliac arteries 5-0 Femoral artery 5-0 Popliteal above the knee 5-0 or 6-0 Popliteal below the knee 6-0 Calf artery 6-0 or 7-0 Carotid 6-0 Brachial 6-0 Subclavian 5-0 Renal – visceral 6-0 15.6 Arteriotomy When performing an arteriotomy it is important to avoid damaging the vessel’s posterior wall, to choose the right direction of arteriotomy, and to close it properly. An arteriotomy starts with punc-ture with a pointed scalpel blade (#11) with the edge turned away from the surgeon. When a punc-ture bleeding is obtained, the blade is moved for-ward and upward to avoid injuries to the posterior wall. The lower blade of a 60° vascular scissors (Pott’s scissors) is inserted into the arteriotomy, which is elongated appropriately while ensuring that the scissors is in the true free vascular lumen and not within any of the layers of the vascular wall. Because arteriosclerotic arteries are occa-sionally extremely hard, the best site for arterioto-my is chosen by palpating with a finger to find a soft segment. Choosing the arteriotomy direction, transverse or longitudinal, is sometimes difficult and is worth special consideration. Longitudinal arteriotomy is the most useful and has the advantage of being easily elongated. It allows better inspection of the vascular lumen and can be used for an end-to-side anastomosis if reconstruction is necessary. On the other hand, it must be closed with a patch to avoid narrowing of arteries with a diameter <5 mm (see below). Transverse arteriotomy can be considered when the procedure is likely to be limited to an embolec-tomy and when the artery is thinner than 5 mm. When closing the arteriotomy, it is always impor-tant to start by catching the intima with the needle at the distal end of the arteriotomy to avoid dissec-tion and occlusion. A running suture is mainly used (Fig. 15.7), but in transverse arteriotomies in smaller arteries, simple sutures are preferable to avoid the risk of narrowing by a running suture that is too tight. 15.7 Closure with Patch (Patch Angioplasty) The patch technique is very important and useful in all emergency vascular procedures. A patch should always be considered when closing an ar-tery after longitudinal arteriotomy or traumatic injury with a vessel wall defect. A longitudinal su-ture always causes a certain degree of narrowing because the suture needle is placed 1–2 mm from the edge on both sides. A basic rule is that vessels Fig.15.7. Closure of a longitudinal arteriotomy with a running suture 15.7 Closure with Patch (Patch Angioplasty) 185 with diameters <5 mm should be closed with a patch. Occasionally, even larger arteries should be closed by the patch technique. In practice, patches are frequently used for the calf, popliteal, brachial, carotid, and sometimes also the femoral and iliac arteries. The choice of patch material depends on location and the level of contamination. An autol-ogous vein is recommended in the superficial fem-oral artery and distally. In the common femoral artery, iliac arteries, and the aorta, a synthetic polyester or polytetrafluoroethylene (PTFE) graft is most commonly used. The patch technique is demonstrated in Fig. 15.8. The patch should be cut to an appropriate width, aiming to compensate for the diameter loss but with some oversizing. Too large a patch will cause a disadvantageous enlargement, which sub-sequently might lead to increased risk for develop-ment of aneurysms and thrombotic occlusions. The patch is shaped at the end in a rounded fash-ion. The suture is started at one of the ends, pos-sibly with retaining sutures in both ends. It is always important to ensure that the distal intimal edge is secured by the suture. The suture is tied in the middle of the patch and never at one of the ends. NOTE Always consider using a patch when closing vessels <5 mm in diameter. Fig.15.8. Patch closure of a longi-tudinal arteriotomy.aThe suture is started distally (downstream) with the needle from inside to out to secure the distal intima. The first su-ture can be tied to secure the patch before proceeding with the suture row. bThe suture is continued in a running fashion in both directions and always with the needle running from the inside to the outside of the artery. When the proximal end of the arteriotomy is approached, the patch has to be cut and trimmed. cThe sutures are continued until they meet on one of the sides. Check inflow and backflow before tying 186 Chapter 15 General Principles of Vascular Surgical Technique 15.8 Interposition Graft To bridge a defect in an artery a piece of a vascular graft is interponated. A vein graft is used for the arms and infrainguinally in the legs. In larger arteries including the iliac arteries and the aorta, a synthetic prosthesis can be used. If the vessels that are going to be anastomosed end to end have dif-ferent diameters, the ends should be cut obliquely to adjust the circumference of both ends to each other. After transverse resection of the thinner vessel, its end is cut longitudinally and the corners trimmed. The larger vessel also needs to be cut slightly transversally to avoid kinking in the anas-tomosis (Fig. 15.9). Also, when thinner vessels are going to be anastomosed end to end, the circum-ference and width of the anastomosis must be ensured by cutting both ends obliquely. This will minimize the risk for narrowing in the suture row. If the anastomosis is started by two diametri-cally opposite holding sutures, the suture adjust-ment is facilitated and the posterior aspect can easily be rotated with the two holding sutures. The anastomosis is then completed with a running su-ture of appropriate size (Fig. 15.10). As pointed out Fig.15.9. When two vessels with different diameters are being sutured end to end, the smaller has to be slit open and the edges trimmed to fit the larger one, which must be cut somewhat obliquely to avoid kinking Fig.15.10. End-to-end anasto-mosis starting with two opposite and tied sutures that can be used to turn the vessel for access to all sides, allowing completion of the anastomosis with running or simple sutures, depending on the diameters ... - tailieumienphi.vn