The radial artery: a forgotten conduit

The Effect of Previous Transradial Catheterization on Radial Forearm Free Flaps

Radial forearm free flaps (RFFF) are a versatile option for the reconstruction of a wide variety of soft tissue defects and are particularly common in head and neck surgery. Benefits of RFFF include a relatively short operating time, a long pedicle, and a thinner, more pliable flap. However, in addition to its role in reconstructive surgery, the radial artery may be utilized for a number of other procedures including coronary angiography and percutaneous coronary interventions. Concern has previously been raised that prior catheterization may deleteriously affect the function of the radial artery and in the field of cardiothoracic surgery, individuals are increasingly advising against its use as a graft for coronary artery bypass graft surgery in such circumstances. Despite this, little is known about the effect on RFFF. In this review article, we concisely consider the available evidence of the effect of previous transradial catheterization on the radial artery and discuss the implications for reconstructive surgery. We then summarize the key considerations regarding their use in current practice.

Open radial artery harvesting better preserves endothelial function compared to the endoscopic approach

OBJECTIVES

Both the open and endovascular techniques are commonly used for harvesting the radial artery (ORAH and ERAH, respectively), and yet, very little is known about the effects of these 2 techniques on endothelial integrity and function of the radial artery (RA). The aim of this study was to assess the endothelial integrity and function of RA harvested using the 2 approaches.

METHODS

Two independent surgical teams working in the same institution routinely use the RA for coronary artery bypass grafting exclusively employing either ORAH or ERAH. Thirty-nine consecutive patients were enrolled in this comparative study. Endothelial function after ORAH or ERAH was assessed by using the wire myograph system. The integrity of the RA endothelium was evaluated by immunohistochemical staining for erythroblast transformation specific-related gene.

RESULTS

The vasodilation in response to acetylcholine was significantly higher in RA harvested with ORAH (P ≤ 0.001 versus ERAH). Endothelial integrity was not different between the 2 groups.

CONCLUSIONS

ORAH is associated with a significantly higher endothelium-dependent vasodilation. Further investigation on the potential implications of these findings in terms of graft spasm and patency as well as clinical outcomes are needed.

Right internal thoracic or radial artery as the second arterial conduit for coronary artery bypass surgery

PURPOSE OF REVIEW

To summarize the available evidence on the use of the right internal thoracic artery (RITA) and the radial artery as the second arterial graft in coronary artery bypass surgery.

RECENT FINDINGS

The current data support the equipoise of the two conduits in terms of clinical and angiographic outcomes. Both RITA and radial artery have better patency than saphenous vein grafts. The use of the RITA carries an increased risk of deep sternal wound infection (DSWI) if the artery is harvested as pedicle. Bilateral internal thoracic artery grafting is more technically demanding than radial artery use and there is a volume-outcome relationship in terms of mortality and incidence of DSWI. The radial artery is preferable over RITA in right-sided or distal circumflex artery targets with high-degree stenosis and in patients at higher risk for DSWI, whereas it is not recommended to graft vessels with moderate stenosis and in cases of insufficient collateralization from the ulnar artery or previous transradial procedures.

SUMMARY

The patency rate and clinical outcomes of radial artery and RITA are similar. The use of one or the other should be based on a careful evaluation of the patient's coronary anatomy and comorbidities, the conduit availability and the surgeon's and center's experience.

Lessons learned from Radial Artery Database International ALliance (RADIAL)

Coronary artery bypass graft (CABG) surgery was first performed in the 1960s. As the surgery has evolved, there has been a growing interest in the use of multiple arterial grafts in CABG. Since the re-introduction of the radial artery (RA) to clinical use as a bypass conduit in the 1990s, there have been several randomized controlled trials (RCTs) which have compared saphenous vein graft (SVG) conduits to RA use in CABG. While most trials have shown improved patency of the RA, none of them have been able to demonstrate a survival benefit using the arterial conduit. In this review, we examine the existing RCTs on the subject. We then look at our solution to the decades-old inquiry regarding the RA compared with the SVG. The Radial Artery Database International ALliance (RADIAL) project is an individual patient-level meta-analysis developed to adequately power a study to assess if the RA has superior clinical outcomes compared with the SVG. We describe the process by which this investigation was conducted and the collaboration necessary to achieve success.

Bilateral internal thoracic artery use in coronary bypass surgery: is there a benefit?

Purpose

Over the past three decades, there have been a plethora of retrospective observational data and meta-analyses which support the hypothesis of improved clinical outcomes using bilateral internal thoracic arteries (BITA) when compared to saphenous vein grafts (SVGs). However, recently published results have brought this thinking into doubt. We discuss the existing literature on the subject and attempt to clarify the appropriate use of BITA in coronary artery bypass surgery (CABG).

Methods

A review of all existing meta-analyses on BITA was conducted to better understand the utility of BITA in CABG. A review of the largest randomized controlled trials on the subject was then compared to the observational data.

Results

In all existing meta-analyses, BITA shows a significant advantage over the use of a single internal thoracic artery (SITA) with SVGs. The two largest randomized controlled trials evaluating BITA failed to show a survival advantage and brought into question the complications associated with BITA.

Conclusions

At present, the use of multiple arterial grafts remains a reasonable choice, particularly in young patients, provided that their use does not increase the operative risk. Further evidence currently being collected may lend a definitive answer in the near future.

Fractional flow reserve to guide and to assess coronary artery bypass grafting

The aim of this review is to highlight the role of invasive functional evaluation in patients in whom coronary artery bypass graft (CABG) is indicated, and to examine the clinical evidence available in favour of fractional flow reserve (FFR) adoption in these patients, outline appropriate use, as well as point out potential pitfalls. FFR after CABG will also be reviewed, highlighting its correct interpretation and adoption when applied to both native coronary arteries and bypass grafts. Practice European guidelines support the use of FFR to complement coronary angiography with the highest degree of recommendation (Class IA) for the assessment of coronary stenosis before undertaking myocardial revascularization when previous non-invasive functional evaluation is unavailable or not conclusive. As a result, FFR has been adopted in routine clinical practice to guide clinicians decision as to whether or not perform a revascularization. Of note, due to the increasing confidence of the interventional cardiologists, FFR guidance is also being implemented to indicate or guide CABG. This is in anticipation of supportive clear-cut evidence, since recommendations for FFR adoption were based on randomized clinical trials investigating percutaneous coronary intervention (PCI) strategies in which patients with typical indications for CABG were excluded (e.g. left main disease, valvular disease, and coronary anatomy unsuitable for PCI). Based on the critical appraisal of the literature, FFR can play an important role in risk stratification and determining management strategy of patients either before or after CABG.

Radial Artery as a Coronary Artery Bypass Conduit: 20-Year Results

BACKGROUND

There is a lack of evidence for the choice of the second conduit in coronary surgery. The radial artery (RA) is a possible option, but few data on very-long-term outcomes exist.

OBJECTIVES

This study describes 20-year results of RA grafts used for coronary artery bypass grafting and the effects of RA removal on forearm circulation.

METHODS

We report the results of the prospective 20-year follow-up of the first 100 consecutive patients who received the RA as a coronary bypass conduit at our institution.

RESULTS

Follow-up was 100% complete. There were 64 deaths, 23 (35.9%) from cardiovascular causes. Kaplan-Meier 20-year survival was 31%. Of the 36 survivors, 33 (91.6%) underwent RA graft control at a mean of 19.0 ± 2.5 years after surgery. The RA was found to be patent in 24 cases (84.8% patency). In the overall population, probability of graft failure at 20 years was 19.0 ± 0.2% for the left internal thoracic artery (ITA), 25.0 ± 0.2% for the RA, and 55.0 ± 0.2% for the saphenous vein (p = 0.002 for RA vs. saphenous vein, 0.11 for RA vs. ITA, and p < 0.001 for ITA vs. saphenous vein). Target vessel stenosis >90%, but not location of distal anastomosis, significantly influenced long-term RA graft patency. No patients reported hand or forearm symptoms. The ulnar artery diameter was increased in the operated arm (2.44 ± 0.43 mm vs. 2.01 ± 0.47 mm; p < 0.05) and correlated with the peak systolic velocity of the second palmar digital artery (Pearson coefficient: 0.621; p < 0.05).

CONCLUSIONS

The 20-year patency rate of RA grafts is good, and not inferior to the ITA, especially when the conduit is used to graft a vessel with >90% stenosis. RA harvesting does not lead to hand or forearm symptoms, even at a very-long-term follow-up.

Does Previous Transradial Catheterization Preclude Use of the Radial Artery as a Conduit in Coronary Artery Bypass Surgery?

The radial artery (RA) is a commonly used conduit for coronary artery bypass grafting, and recent studies have demonstrated that it provides superior long-term patency rates to the saphenous vein in most situations. In addition, the RA is also being used with increasing frequency as the access point for coronary angiography and percutaneous coronary interventions. However, there has been concern for many years that these transradial procedures may have a detrimental impact on the function of RA grafts used in coronary artery bypass grafting, and there is now comprehensive evidence that such interventions cause morphologic and functional damage to the artery in situ. Despite this, there remain remarkably few studies investigating the use of previously cannulated RAs as grafts in coronary artery bypass surgery, and there are no clear guidelines on the use of the RA in coronary artery bypass grafting after its catheterization. This article will review concisely the evidence that transradial procedures cause damage to the RA, and discuss the impact this could have on previously cannulated RAs used as coronary artery bypass grafting conduits. On the basis of the evidence assessed, we make a number of recommendations to both surgeons and cardiologists regarding use of the RA in cardiovascular procedures.

Cardiac surgery 2015 reviewed

For the year 2015, almost 19,000 published references can be found in PubMed when entering the search term "cardiac surgery". The last year has been again characterized by lively discussions in the fields where classic cardiac surgery and modern interventional techniques overlap. Lacking evidence in the field of coronary revascularization with either percutaneous coronary intervention or bypass surgery has been added. As in the years before, CABG remains the gold standard for the revascularization of complex stable triple-vessel disease. Plenty of new information has been presented comparing the conventional to transcatheter aortic valve implantation (TAVI) demonstrating similar short- and mid-term outcomes at high and low risk, but even a survival advantage with transfemoral TAVI at intermediate risk. In addition, there were many relevant and interesting other contributions from the purely operative arena. This review article will summarize the most pertinent publications in the fields of coronary revascularization, surgical treatment of valve disease, heart failure (i.e., transplantation and ventricular assist devices), and aortic surgery. While the article does not have the expectation of being complete and cannot be free of individual interpretation, it provides a condensed summary that is intended to give the reader "solid ground" for up-to-date decision-making in cardiac surgery.

Biodegradable Metals for Cardiovascular Stents: from Clinical Concerns to Recent Zn-Alloys

Metallic stents are used to promote revascularization and maintain patency of plaqued or damaged arteries following balloon angioplasty. To mitigate the long-term side effects associated with corrosion-resistant stents (i.e., chronic inflammation and late stage thrombosis), a new generation of so-called "bioabsorbable" stents is currently being developed. The bioabsorbable coronary stents will corrode and be absorbed by the artery after completing their task as vascular scaffolding. Research spanning the last two decades has focused on biodegradable polymeric, iron-based, and magnesium-based stent materials. The inherent mechanical and surface properties of metals make them more attractive stent material candidates than their polymeric counterparts. A third class of metallic bioabsorbable materials that are based on zinc has been introduced in the last few years. This new zinc-based class of materials demonstrates the potential for an absorbable metallic stent with the mechanical and biodegradation characteristics required for optimal stent performance. This review compares bioabsorbable materials and summarizes progress towards bioabsorbable stents. It emphasizes the current understanding of physiological and biological benefits of zinc and its biocompatibility. Finally, the review provides an outlook on challenges in designing zinc-based stents of optimal mechanical properties and biodegradation rate.

Multiple arterial grafting for coronary revascularization: "A guide for the perplexed"

The surgical literature abounds with articles extolling the benefits of arterial grafting for patients with advanced coronary artery disease in need of surgical revascularization. However, examination of clinical performance demonstrates that extensive use of arterial grafting is highly selective and generally uncommon. Rather than to merely repeat multiple excellent recent literature reviews, the goal herein is to provide the reader with a guide to the evaluation of the current literature as well as to suggest fruitful areas for further research. More circumspect understanding of the strengths and weaknesses of our current knowledge base will not only help to explain the current apparent disparity between theory and practice but will hopefully inform future decision-making and patient care.