Arterial conduits for extremity microvascular bypass surgery

Resurfacing of lower extremities: Versatility of thigh flap as pedicle extension graft with consecutive thoracodorsal artery perforator-based flap

BACKGROUND

For successful microsurgical reconstruction using free tissue transfer, healthy recipient vessels must be obtained from outside the zone of injury. Securing an appropriate length pedicle length is also essential, and various techniques for lengthening a vascular pedicle have been developed. Herein, we present our experience using the descending branch (DB) of the lateral circumflex femoral vessels (LCFVs) with a thigh flap as an extender graft for consecutive second flap.

METHODS

We reconstructed the complex and vessel-depleted defects of nine patients. The mean age was 47.6 years. The defects were located in the lower leg in four patients, in the perineum in two patients and in the forearm in three patients. The two patients who suffered from Fournier's gangrene underwent a pedicled anteromedial thigh (pAMT) flap with the DB of the LCFVs and seven patients, five who suffered high-energy trauma and two who had scar contracture, underwent a free anterolateral thigh (ALT) flap with the distal run-off DB of the LCFVs. In all patients, second consecutive free latissimus dorsi or thoracodorsal artery perforator flaps were prepared and the thoracodorsal vessels of the second flap were anastomosed to the distal DB of the LCFVs.

RESULTS

The total length of the thigh flap pedicles measured from both ends of the DB of the LCFVs varied from 15 to 20 cm, which was sufficient for use as a vascular conduit. Of the 18 flaps, 17 survived completely without any complications and 1 pAMT flap showed partial necrosis, which was covered with a perineal perforator-based island flap. The mean follow-up period was 16.7 months. Unfortunately, one patient, who suffered a total amputation below the knee and had replantation surgery, underwent amputation due to venous congestion in the distal leg. However, the previous two flaps survived and were used for coverage of the stump.

CONCLUSIONS

Using a thigh flap as a vascular extender graft for second flap may be an alternative option in vessel-depleted reconstructions.

A Review of Arterial Grafts Used for Microvascular Arterial Reconstruction

Arterial grafts are sometimes used in microvascular reconstruction and their clinical benefit over standard venous grafts is unknown. To determine arterial graft utilization in clinical microvascular arterial reconstruction, a review of the literature was done. PubMed search resulted with 4,352 finds, and after screening for relevance, 11 articles reporting on 55 arterial grafts were analyzed. All reports were retrospective studies, case reports, and case series, with no randomized controlled trials. Two retrospective series reported better patency of arterial versus venous grafts in upper-limb revascularization for chronic occlusion, but the findings were highly biased. Better patency of arterial grafts did not lead to higher rate of clinical improvement. Antiplatelet and lipid-lowering agents seem to be underused in venous graft recipients and use of no-touch venous grafting has not been reported. Based on the available data, routine use of arterial grafts cannot be recommended. Studies that show better patency of arterial grafts in hand revascularization for chronic vascular insufficiency are retrospective and biased, so a randomized controlled trial is needed.

Comparison of venous repair results using either arterial or vein grafts in a crush-avulsion injury model

Background/aim

Venous insufficiency after replantation or revascularization is one of the most common causes of limb loss in either the short or the long term. The aim of this study was to evaluate the results of a new technique to overcome venous insufficiency.

Materials and Methods

A crush-avulsion type of injury was formed in the femoral veins of rats of 3 separate groups. In the control group, primary repair was applied to the damaged veins and the remaining 2 groups were repaired with either an arterial graft or a vein graft. The success rates of anastomosis were then compared.

Results

In the control group the patency rate was 25% in the 2nd hour, 12.5% on the 2nd day, and 12.5% on the 10th day. The patency rate in the vein group was 87.5% in the 2nd hour, 50% on the 2nd day, and 37.5% on the 10th day, whereas the patency rates in the artery group were 100% in the 2nd hour, 87.5% on the 2nd day, and 75% on the 10th day.

Conclusion

Microsurgery requires experience and patience. It can be considered that the use of arterial grafts for venous repair in replantation after crush-avulsion type amputations can increase the success rate of replantation.

A systematic review of isolated radial artery harvesting as a conduit for lower limb bypass grafting

BACKGROUND

Whilst autologous vein conduits have been heralded as the first-line approach for patients undergoing lower limb bypass grafting procedures, patients with peripheral arterial occlusive disease may have exhausted venous options given prior use for cardiac surgery, varicose vein surgery, or lower limb revascularization. Hence, the use of a radial artery graft may serve as a viable alternative.

METHODS

The systematic review was performed in accordance to the Preferred Reporting Items for Systematic Review and Meta-analysis guidelines. An electronic search was performed on the following databases: Medline (via PubMed); EMBASE; Cochrane library to search for relevant publications. A narrative analysis was conducted.

RESULTS

Four publications were included in this review including two retrospective cohort studies, one case series, and one case report, with a total of 43 patients. The most common indication for lower limb bypass grafting was critical limb ischemia, and the radial artery was chosen as graft conduit, most commonly due to the absence of suitable arm or leg vein. There was one case of 30-day mortality and 11 reinterventions.

CONCLUSION

Despite the encouraging results, the paucity of high-quality studies prevents the establishment of any firm conclusion. This warrants the need for appropriately conducted randomized controlled trials to compare the radial artery graft to autologous vein grafts and prosthetic grafts for lower limb bypass grafting.

Options for revascularization: artery versus vein: technical considerations

Vascular grafts, as either interpositional conduits or bypass grafts, can be used for revascularization procedures in the upper extremity. Vein grafts are more readily available and can be easier to harvest. Arterial grafts may provide superior patency rates compared with vein grafts. Arterial grafts can be located and harvested with consistent and reliable anatomy throughout the body.

Arterial conduits for distal upper extremity bypass

Vascular bypass is an accepted surgical procedure for treatment of hand and digital ischemia that is the result of identifiable arterial disease. Although vein grafts have traditionally been used as vascular conduits for reconstruction, arterial grafts present a better alternative, physiologically, for reconstruction and may result in superior outcomes. Arteries suitable for grafts are not abundant and, therefore, upper extremity surgeons must be informed about possible donor sites and techniques for harvest.

A systematic review of the outcomes of distal upper extremity bypass surgery with arterial and venous conduits

PURPOSE

To conduct a systematic review of literature evaluating efficacy of venous and arterial grafts for distal upper extremity bypass surgery.

METHODS

A PubMed search using MeSH terms "veins/surgery" OR "arteries/surgery" AND "radial artery/surgery" OR "ulnar artery/surgery" yielded 794 studies. Manual review produced 42 studies based on inclusion criteria of reported distal upper extremity bypass surgery, complete information on graft type used, examined patency of reconstruction, and described method for determining patency. Studies meeting inclusion criteria underwent data extraction focusing on demographics, revascularization site, conduit type, microsurgical technique, subjective/objective outcomes, and postoperative anticoagulation regimens.

RESULTS

Sixteen studies met the inclusion criteria. In 145 patients, 152 grafts were performed for upper extremity revascularization, including 120 grafts for revascularization of distal ulnar artery circulation, 31 for distal radial artery circulation, and 1 for both distal ulnar and radial artery occlusions. Overall patency rate was 87% at an average follow-up of 34 months. Of 152 bypass grafts, 19 were arterial conduits. Donor sites included the deep inferior epigastric artery, subscapular artery, thoracodorsal artery, and descending branch of the lateral femoral circumflex artery. At a mean follow-up of 18 months, arterial conduit patency was 100%. The remaining 133 bypass procedures used vein grafts from various donor sites, including the saphenous, cephalic, and basilic veins. At an average follow-up of 37 months, overall vein graft patency rate was 85%. There was a statistically significant difference between patency rates of arterial conduits compared with venous conduits. All studies reported improved ischemic symptoms including reduction of cold sensitivity, pain, and digital ulceration.

CONCLUSIONS

This review showed a high patency rate and clinical efficacy of distal upper extremity bypass surgery with a mean follow-up of almost 3 years. There may be a benefit of using arterial versus venous conduits, although further examination is needed given the small number of arterial reconstructions reported.

Radial artery cannulation: a comprehensive review of recent anatomic and physiologic investigations

Consistent anatomic accessibility, ease of cannulation, and a low rate of complications have made the radial artery the preferred site for arterial cannulation. Radial artery catheterization is a relatively safe procedure with an incidence of permanent ischemic complications of 0.09%. Although its anatomy in the forearm and the hand is variable, adequate collateral flow in the event of radial artery thrombosis is present in most patients. Harvesting of the radial artery as a conduit for coronary artery bypass grafting, advances in plastic and reconstructive surgery of the hand, and its use as an entry site for cardiac catheterization has provided new insight into the collateral blood flow to the hand and the impact of radial arterial instrumentation. The Modified Allen's Test has been the most frequently used method to clinically assess adequacy of ulnar artery collateral flow despite the lack of evidence that it can predict ischemic complications in the setting of radial artery occlusion. Doppler ultrasound can be used to evaluate collateral hand perfusion in an effort to stratify risk of potential ischemic injury from cannulation. Limited research has demonstrated a beneficial effect of heparinized flush solutions on arterial catheter patency but only in patients with prolonged monitoring (>24 h). Conservative management may be equally as effective as surgical intervention in treating ischemic complications resulting from radial artery cannulation. Limited clinical experience with the ultrasound-guided arterial cannulation method suggests that this technique is associated with increased success of cannulation with fewer attempts. Whether use of the latter technique is associated with a decrease in complications has not yet been verified in prospective studies. Research is needed to assess the safety of using the ulnar artery as an alternative to radial artery cannulation because the proximity and attachments of the ulnar artery to the ulnar nerve may potentially expose it to a higher risk of injury.

The Deep Inferior Epigastric Artery: Anatomy and Applicability as a Source of Microvascular Arterial Grafts

BACKGROUND

Arterial grafts are superior to venous grafts when used for microvascular grafting procedures. Advantages of arterial grafts include anatomical taper, improved size match, improved handling characteristics, and superior patency rates. The deep inferior epigastric artery may be used as a source of microvascular graft to replace damaged or diseased arterial segments. By studying cadaver dissections, it is possible to estimate the clinically usable length and caliber of the deep inferior epigastric artery.

METHODS

Thirty-four preserved cadavers were dissected and 63 deep inferior epigastric arterial systems were removed and measured. The deep inferior epigastric artery was used as an arterial conduit to bypass across nine wrists in eight patients.

RESULTS

The mean length from the external iliac artery to the point at which the vessel displayed an external diameter of 1 mm was 14.06 +/- 2.54 cm. The deep inferior epigastric artery has been used in nine clinical cases as an arterial conduit to bypass distal to the wrist. All nine bypasses were patent 1 year postoperatively, without donor-site complication.

CONCLUSION

The deep inferior epigastric artery is a morphologically reliable and clinically useful source of arterial grafts.