Off-pump Skeletonized Versus Pedicled Left Internal Mammary Artery Grafting: Mid-term Results

Reducing vasospasm of vein and arterial conduits used in coronary artery bypass surgery: are solutions the solution or is preserved perivascular fat the answer?

The three main conduits used for myocardial revascularization in patients with coronary artery disease (CAD) are the internal thoracic artery (ITA), radial artery (RA) and saphenous vein (SV). In coronary artery bypass grafting (CABG) conduits may be harvested with perivascular adipose tissue (PVAT) intact (pedicled) or removed (skeletonized). Various studies have shown that the patency rate of these bypass grafts may be affected by the preservation or removal of PVAT. Vasospasm is often encountered at harvesting, a condition that has both immediate and long term effects on graft performance. During surgery a variety of antispastic solutions are routinely used on conduits that have anti-contractile and/or vasorelaxant actions. Spasm may be abolished or reduced when PVAT is left intact at harvesting and this is particularly the case for the SV. The protective properties of PVAT are multifactorial, ranging from its mechanical properties in supporting the graft after implantation to the beneficial effect of adipocyte-derived factors. This review aims to outline the possible mechanisms through which preserved PVAT could alleviate vasospasm and improve conduit performance in CABG. Moreover, since preservation of PVAT reduces spasm at and after surgery this review also considers whether antispastic solutions are needed if conduits are harvested with PVAT intact.

A systematic review and meta-analysis of internal thoracic artery harvesting techniques: Skeletonized vs pedicled

OBJECTIVES

The aim of this meta-analysis was to compare clinical and angiographic outcomes of skeletonized versus pedicled internal thoracic artery for coronary artery bypass grafting.

METHODS

A comprehensive search on Ovid MEDLINE, Ovid EMBASE and Scopus was performed from inception to December 2022. The primary outcome was follow-up mortality and graft failure. Secondary outcomes were repeat revascularization, cardiovascular death and operative mortality, myocardial infarction, stroke, and sternal wound complications (SWCs). Pooled estimate for follow-up outcomes was summarized as incidence rate ratio (IRR) and 95% confidence interval (CI) while short-term outcomes were pooled as odds ratio (OR) and 95% CI. For all outcomes, inverse variance weighting was used for pooling.

RESULTS

Twenty-eight studies, including 7 randomized trials and 21 observational studies, for a total of 5664 patients in the skeletonized group and 7434 in the pedicled group, were included in the analysis. At a mean weighted follow-up of 4.8 years, there was no difference in mortality between the two groups (IRR 1.14; 95% CI 0.59-2.20). However, the skeletonized group had a higher incidence of graft failure compared to the pedicled group (IRR 1.87, 95% CI 1.33-2.63) but a lower risk of SWCs (OR 0.42; 95% CI 0.30-0.60). There was no difference in short-term outcomes.

CONCLUSIONS

Compared to the pedicled harvesting technique, skeletonization of the internal thoracic artery is associated with higher rate of graft failure and lower risk of SWCs without mortality difference.

Surgical Strategy for Sternal Closure in Patients with Surgical Myocardial Revascularization Using Mammary Arteries

BACKGROUND

Coronary artery bypass grafting has evolved from all venous grafts to bilateral mammary artery (BIMA) grafting. This was possible due to the long-term patency of the left and right internal mammary demonstrated in angiography studies compared to venous grafts. However, despite higher survival rates when using bilateral mammary arteries, multiple studies report a higher rate of surgical site infections, most notably deep sternal wound infections, a so-called "never event".

METHODS

We designed a prospective study between 1 January 2022 and 31 December 2022 and included all patients proposed for total arterial myocardial revascularization in order to investigate the rate of surgical site infections (SSI). Chest closure in all patients was performed using a three-step protocol. The first step refers to sternal closure. If the patient's BMI is below 35 kg/m2, sternal closure is achieved using the "butterfly" technique with standard steel wires. If the patient's BMI exceeds 35 kg/m2, we use nitinol clips or hybrid wire cable ties according to the surgeon's preference for sternal closure. The main advantages of these systems are a larger implant-to-bone contact with a reduced risk of bone fracture. The second step refers to presternal fat closure with two resorbable monofilament sutures in a way that the edges of the skin perfectly align at the end. The third step is skin closure combined with negative pressure wound therapy.

RESULTS

This system was applied to 217 patients. A total of 197 patients had bilateral mammary artery grafts. We report only 13 (5.9%) superficial SSI and only one (0.46%) deep SSI. The preoperative risk of major wound infection was 3.9 +/- 2.7. Bilateral mammary artery grafting was not associated with surgical site infection in a univariate analysis.

CONCLUSIONS

We believe this strategy of sternal wound closure can reduce the incidence of deep surgical site infection when two mammary arteries are used in coronary artery bypass surgery.

Effect of skeletonisation and pedicled bilateral internal mammary artery grafting in coronary artery bypass surgery on post-operative wound infection: A meta-analysis

The results showed that different internal thoracic artery (ITA) was associated with the rate of postoperative wound infection and the severity of pain following coronary artery bypass grafting (CABG). In order to ascertain if there was any genuine difference in the rate of postoperative infection and severity of the pain, we conducted a meta-analysis to evaluate if there was any actual difference in the wound complication that had been identified with the ITA method. Through EMBASE, Cochrane Library and Pubmed, and so forth, we systematically reviewed the results by August 2023, which compared the impact of skeletonised versus pedicled internal mammary artery (IMA) on wound complications following CABG. The trial data have been pooled and analysed in order to determine if a randomisation or fixed-effect model should be applied. The meta-analysis of data was performed with Revman 5.3 software. The results of this meta-study included 252 related articles from four main databases, and nine articles were chosen to be extracted and analysed. A total of 3320 patients were treated with coronary artery transplantation. Based on current data analysis, we have shown that the rate of postoperative wound infections is reduced by the use of the skeletonised internal mammary artery (SIMA) (OR, 1.84; 95% CI, 1.13, 3.01; p = 0.01). But the results showed that there were no statistically significant differences in the post-operation pain score of the patients (MD, 0.09; 95% CI, -0.58, 0.76; p = 0.79). Furthermore, the duration of the operation was not significantly different between the SIMA and pedicled internal mammary artery (PIMA) (MD, 3.30; 95% CI, -3.13, 9.73; p = 0.31). Overall, the SIMA decreased the rate of postoperative wound infection in CABG patients than the PIMA.

Expert systematic review on the choice of conduits for coronary artery bypass grafting: endorsed by the European Association for Cardio-Thoracic Surgery (EACTS) and The Society of Thoracic Surgeons (STS)

PREAMBLE

The finalized document was endorsed by the EACTS Council and STS Executive Committee before being simultaneously published in the European Journal of Cardio-thoracic Surgery (EJCTS) and The Annals of Thoracic Surgery (The Annals) and the Journal of Thoracic and Cardiovascular Surgery (JTCVS).

Skeletonized vs Pedicled Internal Mammary Artery Graft Harvesting in Coronary Artery Bypass Surgery: A Post Hoc Analysis From the COMPASS Trial

Importance

The relative safety and patency of skeletonized vs pedicled internal mammary artery grafts in patients undergoing coronary artery bypass graft (CABG) surgery are unknown.

Objective

To investigate the association of skeletonized vs pedicled harvesting with internal mammary artery graft patency and clinical outcomes 1 year after CABG surgery.

Design, Setting, and Participants

This study was a post hoc analysis of the multicenter, randomized, double-blind, placebo-controlled Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) clinical trial, which enrolled 27 395 patients from 602 centers in 33 countries from March 2013 through May 2016. Eligibility criteria for the trial included CABG surgery for coronary artery disease with at least 2 grafts implanted and an estimated glomerular filtration rate of at least 30 mL/min. A total of 1002 of 1448 patients were randomized to the CABG arm of the COMPASS trial and underwent skeletonized (282 [28.1%]) or pedicled (720 [71.9%]) internal mammary artery harvesting. The patients had evaluable angiography results 1 year after surgery. Data were analyzed from October 11, 2019, to May 14, 2020.

Interventions

Patients underwent graft harvesting with either the pedicled technique or skeletonized technique.

Main Outcomes and Measures

The primary outcome was graft occlusion 1 year after CABG surgery, as assessed by computed tomography angiography.

Results

A total of 1002 patients underwent skeletonized (282 [28.1%]; mean [SD] age, 65.9 [8.1] years; 229 men [81.2%]; 194 White patients [68.8%]) or pedicled (720 [71.9%]; mean [SD] age, 64.8 [7.6] years; 603 men [83.8%]; 455 White patients [63.2%]) internal mammary artery harvesting. Rates of internal mammary artery graft occlusion 1 year after CABG surgery were higher in the skeletonized group than in the pedicled group (33 of 344 [9.6%] vs 30 of 764 [3.9%]; graft-level adjusted odds ratio, 2.41; 95% CI, 1.39-4.20; P = .002), including the left internal mammary artery to left anterior descending artery (21 of 289 [7.3%] vs 25 of 725 [3.4%]; graft-level adjusted odds ratio, 2.10; 95% CI, 1.14-3.88, P = .02). After a mean follow-up of 23 months, skeletonized graft harvesting was also associated with a higher rate of major adverse cardiovascular events (20 [7.1%] vs 15 [2.1%]; adjusted hazard ratio, 3.19; 95% CI, 1.53-6.67; P = .002) and repeated revascularization (14 [5.0%] vs 10 [1.4%]; adjusted hazard ratio, 2.75; 95% CI, 1.10-6.88; P = .03).

Conclusions and Relevance

This post hoc analysis of the COMPASS randomized clinical trial found that harvesting of the internal mammary artery during CABG surgery using a skeletonized technique was associated with a higher rate of graft occlusion and worse clinical outcomes than the traditional pedicled technique. Future randomized clinical trials are needed to establish the safety and patency of the skeletonized technique.

Trial Registration

ClinicalTrials.gov Identifier: NCT01776424.

Skeletonized or Pedicled Harvesting of Left Internal Mammary Artery: A Systematic Review and Meta-analysis

We sought to compare clinical outcomes in skeletonized versus pedicled left internal mammary artery (LIMA) grafts in elective coronary artery bypass grafting through a systematic review and meta-analysis. A comprehensive electronic literature search of PubMed, Ovid, Embase, and Scopus was conducted from inception to January 2020. Only short-term (30 days) studies which compared both techniques have been included in our analysis. Primary outcomes were post anastomosis flow rate and sternal wound infection rate (SWI); secondary outcomes were conduit length, acute myocardial infarction and 30-day mortality. Thirteen articles with a total of 6222 patients met the inclusion criteria. Except for the prevalence of diabetes mellitus being significantly lower in the skeletonized cohort (odds ratio [OR] 0.77 95% confidence interval [CI] [0.61, 0.97], P = 0.03), there were no differences in the preoperative demographics between the 2 groups. The skeletonized LIMA conduit was significantly longer when compared to the pedicled conduit (weighted mean difference -2.64 cm 95% CI [-3.71, -1.56], P < 0.0001). SWI rates were not significantly different in the skeletonized versus pedicled LIMA group (OR 0.71 95% CI [0.47, 1.06], P = 0.10). New onset of acute myocardial infarction and 30-day mortality rate was similar in the 2 groups (OR 1.04 and 0.97, respectively, P > 0.05 in both). The postanastomoses flow rate was higher in skeletonized LIMA (Weighted Mean Difference -11.51 mL/min 95% CI [-20.54, -2.49], P < 0.01). Harvesting the LIMA using the skeletonized technique is associated with higher postanastomosis flow rates and longer conduit lengths; with no difference in SWI and mortality rates when compared to the pedicled technique. We suggest that this technique should be adopted, particularly for BITA harvesting. However, further research is needed to provide clearer indications for both methods.