Anastomoses in the Common Femoral Artery, Vascular Clips or Sutures? A Feasibility Study

Sutureless vascular anastomotic approaches and their potential impacts

Sutureless anastomotic devices present several advantages over traditional suture anastomosis, including expanded global access to microvascular surgery, shorter operation and ischemic times, and reduced costs. However, their adaptation for arterial use remains a challenge. This review aims to provide a comprehensive overview of sutureless anastomotic approaches that are either FDA-approved or under investigation. These approaches include extraluminal couplers, intraluminal devices, and methods assisted by lasers or vacuums, with a particular emphasis on tissue adhesives. We analyze these devices for artery compatibility, material composition, potential for intimal damage, risks of thrombosis and restenosis, and complications arising from their deployment and maintenance. Additionally, we discuss the challenges faced in the development and clinical application of sutureless anastomotic techniques. Ideally, a sutureless anastomotic device or technique should eliminate the need for vessel eversion, mitigate thrombosis through either biodegradation or the release of antithrombotic drugs, and be easily deployable for broad use. The transformative potential of sutureless anastomotic approaches in microvascular surgery highlights the necessity for ongoing innovation to expand their applications and maximize their benefits.

Drugs to reduce bleeding and transfusion in major open vascular or endovascular surgery: a systematic review and network meta-analysis

BACKGROUND

Vascular surgery may be followed by internal bleeding due to inadequate surgical haemostasis, abnormal clotting, or surgical complications. Bleeding ranges from minor, with no transfusion requirement, to massive, requiring multiple blood product transfusions. There are a number of drugs, given systemically or applied locally, which may reduce the need for blood transfusion.

OBJECTIVES

To assess the effectiveness and safety of anti-fibrinolytic and haemostatic drugs and agents in reducing bleeding and the need for blood transfusion in people undergoing major vascular surgery or vascular procedures with a risk of moderate or severe (> 500 mL) blood loss.

SEARCH METHODS

We searched: Cochrane Central Register of Controlled Trials; MEDLINE; Embase; CINAHL, and Transfusion Evidence Library. We also searched the WHO ICTRP and ClinicalTrials.gov trial registries for ongoing and unpublished trials. Searches used a combination of MeSH and free text terms from database inception to 31 March 2022, without restriction on language or publication status.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in adults of drug treatments to reduce bleeding due to major vascular surgery or vascular procedures with a risk of moderate or severe blood loss, which used placebo, usual care or another drug regimen as control.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were units of red cells transfused and all-cause mortality. Our secondary outcomes included risk of receiving an allogeneic blood product, risk of reoperation or repeat procedure due to bleeding, risk of a thromboembolic event, risk of a serious adverse event and length of hospital stay. We used GRADE to assess certainty of evidence.

MAIN RESULTS

We included 22 RCTs with 3393 participants analysed, of which one RCT with 69 participants was reported only in abstract form, with no usable data. Seven RCTs evaluated systemic drug treatments (three aprotinin, two desmopressin, two tranexamic acid) and 15 RCTs evaluated topical drug treatments (drug-containing bioabsorbable dressings or glues), including fibrin, thrombin, collagen, gelatin, synthetic sealants and one investigational new agent. Most trials were conducted in high-income countries and the majority of the trials only included participants undergoing elective surgery. We also identified two ongoing RCTs. We were unable to perform the planned network meta-analysis due to the sparse reporting of outcomes relevant to this review. Systemic drug treatments We identified seven trials of three systemic drugs: aprotinin, desmopressin and tranexamic acid, all with placebo controls. The trials of aprotinin and desmopressin were small with very low-certainty evidence for all of our outcomes. Tranexamic acid versus placebo was the systemic drug comparison with the largest number of participants (2 trials; 1460 participants), both at low risk of bias. The largest of these included a total of 9535 individuals undergoing a number of different higher risk surgeries and reported limited information on the vascular subgroup (1399 participants). Neither trial reported the number of units of red cells transfused per participant up to 30 days. Three outcomes were associated with very low-certainty evidence due to the very wide confidence intervals (CIs) resulting from small study sizes and low number of events. These were: all-cause mortality up to 30 days; number of participants requiring an allogeneic blood transfusion up to 30 days; and risk of requiring a repeat procedure or operation due to bleeding. Tranexamic acid may have no effect on the risk of thromboembolic events up to 30 days (risk ratio (RR) 1.10, 95% CI 0.88 to 1.36; 1 trial, 1360 participants; low-certainty evidence due to imprecision). There is one large ongoing trial (8320 participants) comparing tranexamic acid versus placebo in people undergoing non-cardiac surgery who are at high risk of requiring a red cell transfusion. This aims to complete recruitment in April 2023. This trial has primary outcomes of proportion of participants transfused with red blood cells and incidence of venous thromboembolism (DVT or PE). Topical drug treatments Most trials of topical drug treatments were at high risk of bias due to their open-label design (compared with usual care, or liquids were compared with sponges). All of the trials were small, most were very small, and few reported clinically relevant outcomes in the postoperative period. Fibrin sealant versus usual care was the topical drug comparison with the largest number of participants (5 trials, 784 participants). The five trials that compared fibrin sealant with usual care were all at high risk of bias, due to the open-label trial design with no measures put in place to minimise reporting bias. All of the trials were funded by pharmaceutical companies. None of the five trials reported the number of red cells transfused per participant up to 30 days or the number of participants requiring an allogeneic blood transfusion up to 30 days. The other three outcomes were associated with very low-certainty evidence with wide confidence intervals due to small sample sizes and the low number of events, these were: all-cause mortality up to 30 days; risk of requiring a repeat procedure due to bleeding; and risk of thromboembolic disease up to 30 days. We identified one large trial (500 participants) comparing fibrin sealant versus usual care in participants undergoing abdominal aortic aneurysm repair, which has not yet started recruitment. This trial lists death due to arterial disease and reintervention rates as primary outcomes.

AUTHORS' CONCLUSIONS

Because of a lack of data, we are uncertain whether any systemic or topical treatments used to reduce bleeding due to major vascular surgery have an effect on: all-cause mortality up to 30 days; risk of requiring a repeat procedure or operation due to bleeding; number of red cells transfused per participant up to 30 days or the number of participants requiring an allogeneic blood transfusion up to 30 days. There may be no effect of tranexamic acid on the risk of thromboembolic events up to 30 days, this is important as there has been concern that this risk may be increased. Trials with sample size targets of thousands of participants and clinically relevant outcomes are needed, and we look forward to seeing the results of the ongoing trials in the future.

A Novel Shape-Memory Monofilament Suture for Minimally Invasive Thoracoscopic Cardiac Surgery

OBJECTIVES

Endoscopic knot tying can complicate or prolong minimally invasive surgical procedures. A novel shape-memory monofilament suture with a spiral tail has been developed to speed up suture fixation during minimally invasive cardiac surgery. The purpose of this study was to evaluate its usefulness and safety in minimally invasive cardiac surgery.

METHODS

We installed a needle with a 4-0 monofilament suture, composed of polyvinylidene difluoride and hexafluoropropylene copolymers, in an originally invented jig and heated it in an oven. By only passing through the needle and then into the spiral made at the tail of the suture, a hangman's knot was easily made. For the fundamental experiment, to evaluate the effectiveness of the novel shape-memory monofilament suture, 4 surgeons with varying thoracoscopic experience tied knots within a simulated minimally invasive setting, using both the novel shape-memory and conventional monofilament sutures. The time elapsed for knot tying and tensile strength of each knot was measured.

RESULTS

The mean knot-tying time was significantly shorter with the novel suture than with the conventional suture (108 ± 29 vs. 172 ± 42 seconds, P = 0.01). The ultimate tensile strength of each knot was 17.4 N in the novel suture and 16.5 N in the conventional suture.

CONCLUSIONS

The novel shape-memory monofilament suture has great potential for reducing operative time of minimally invasive thoracoscopic surgery while retaining the strength of the knot.

A Prospective, Randomized, Multicenter Clinical Trial on the Safety and Efficacy of a Ready-to-Use Fibrin Sealant as an Adjunct to Hemostasis during Vascular Surgery

BACKGROUND

Anastomotic or "stitch hole" bleeding is common during vascular surgery with synthetic material such as Dacron or polytetrafluoroethylene. Hemostatic adjuncts such as fibrin sealant (FS) may reduce blood loss and operating time in such circumstances. We evaluated the safety and the hemostatic effectiveness of a ready-to-use human plasma-derived FS in vascular surgery.

METHODS

Patients with mild/moderate suture line bleeding during elective, open, vascular surgery using synthetic grafts or patches were studied. In an initial Exploratory Study, all patients were treated with FS Grifols, and in a subsequent Primary Study were randomized in a 2:1 ratio to FS Grifols or manual compression (MC). The primary efficacy end point was time to hemostasis (TTH), assessed at defined intervals from the start of treatment application, during a 10-min observational period. Safety end points (in Exploratory + Primary Studies) included adverse events (AEs), vital signs, physical assessments, common clinical laboratory tests (coagulation, complete blood count, serum clinical chemistry parameters, microscopic urinalysis), viral markers, and immunogenicity.

RESULTS

In the Primary Study, the proportion of patients who achieved hemostasis at the 3-min time point was higher in the FS Grifols group (46.4%, n = 51/110) than in the MC group (26.3%, n = 15/57) (P < 0.05). The benefit was maintained at successive time intervals: 69 FS Grifols patients (62.7%) and 18 MC patients (31.6%) at 4 min; 82 FS Grifols patients (74.5%) and 28 MC patients (49.1%) at 5 min. The differences between the groups persisted for TTH ≤ 7 min and TTH ≤ 10 min. Treatment failure was reported for 13 FS Grifols patients (11.8%) and 16 MC patients (28.1%). TTH was shorter after FS Grifols application than after MC application. Differences were statistically significant in favor of FS Grifols for each TTH category and for the overall comparison (P < 0.001) as well as for each TTH category (cumulative) and for treatment failure (P = 0.016). Overall, AE experience and types of AEs reported were those expected in this patient population and were similar between the 2 treatment groups. The most frequently reported AEs were procedural pain (59.9% and 69.2% of patients in the FS Grifols [n = 72 + 111] and MC [n = 57] groups, respectively) and nausea (23.5% and 19.2% of patients, respectively).

CONCLUSIONS

FS Grifols was efficacious and safe as an adjunct to anastomotic hemostasis in patients undergoing arterial surgery using prosthetic material with mild to moderate bleeding.