Author + information
- Received October 31, 2017
- Revision received January 4, 2018
- Accepted January 5, 2018
- Published online March 5, 2018.
- Mario Gaudino, MDa,∗ (, )
- Francesco Burzotta, MD, PhDb,
- Faisal Bakaeen, MDc,
- Olivier Bertrand, MDd,
- Filippo Crea, MDb,
- Antonino Di Franco, MDa,
- Stephen Fremes, MDe,
- Ferdinand Kiemeneij, MD, PhDf,
- Yves Louvard, MDg,
- Sunil V. Rao, MDh,
- Thomas A. Schwann, MDi,
- James Tatoulis, MDj,
- Robert F. Tranbaugh, MDa,
- Carlo Trani, MD, PhDb,
- Marco Valgimigli, MD, PhDk,
- Pascal Vranckx, MD, PhDl,
- David P. Taggart, MD, PhDm,
- for the Arterial Grafting International Consortium Alliance
- aDepartment of Cardiothoracic Surgery, Weill Cornell Medicine, New York, New York
- bUniversità Cattolica Del Sacro Cuore, Rome, Italy
- cCleveland Clinic, Cleveland, Ohio
- dQuebec Heart and Lung Institute, Quebec City, Quebec, Canada
- eSchulich Heart Centre, Sunnybrook Health Science, University of Toronto, Toronto, Ontario, Canada
- fDepartment of Cardiology, Zuiderzee Medical Center, Lelystad, the Netherlands
- gInstitut Cardiovasculaire Paris Sud, Hopital Jacques Cartier, Massy, France
- hDuke Clinical Research Institute, Durham, North Carolina
- iUniversity of Toledo Medical Center, Toledo, Ohio
- jRoyal Melbourne Hospital, Melbourne, Victoria, Australia
- kSwiss Cardiovascular Center, Bern University Hospital, Bern, Switzerland
- lHartcentrum Hasselt and Faculty of Medicine and Life Sciences Hasselt University, Jessa Ziekenhuis, Hasselt, Belgium
- mUniversity of Oxford, Oxford, United Kingdom
- ↵∗Address for correspondence:
Dr. Mario Gaudino, Department of Cardiothoracic Surgery, Weill Cornell Medicine, 525 East 68th Street, New York, New York 10065.
This article summarizes the current research on the benefits of using the transradial approach for percutaneous procedures and the radial artery as a conduit for coronary artery bypass surgery. Based on the available evidence, the authors provide recommendations for the use of the radial artery in patients undergoing percutaneous or surgical coronary procedures.
Recently, there has been renewed interest in the radial artery (RA) both for cardiovascular surgery and for percutaneous intervention. Among surgeons, the publication of long-term follow-up data and randomized comparative studies has established the role of the RA as a more durable graft than the saphenous vein (SV) for coronary artery bypass operations (CABG) (1). Among cardiologists, transradial access (TRA) has been shown to be a superior alternative to the classic femoral approach for diagnostic catheterization and percutaneous interventions (2–6), and TRA procedures have become increasingly popular. This convergence of interests, however, has elicited concerns that, after TRA, the RA may not be a suitable CABG conduit due to catheter-induced trauma predisposing to premature graft failure and mitigating long-term survival benefits (7).
To date there are no guidelines for the approach to the RA in patients with known or possible coronary artery disease (8). In this paper, we provide guidance for the use of the TRA approach for percutaneous intervention based on the best evidence and use of the RA as a conduit for CABG and suggest recommendations for optimal use of the RA in patients with coronary artery disease.
A writing panel was organized by convening 17 physicians from the fields of clinical cardiology (n = 2), cardiothoracic surgery (n = 7), and interventional cardiology (n = 8), highly experienced in the use of the RA for CABG or TRA. The members of the panel agreed to review the best available research and to provide a document with recommendations. Treatment algorithms were drafted when general agreement among panelists was reached.
In August 2017, a comprehensive search to identify studies that evaluated the use of the RA for TRA and CABG was performed in the following databases from inception to present: Ovid MEDLINE, Ovid EMBASE, and the Cochrane Library (Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials [CENTRAL], and Cochrane Methodology Register). Search keywords included “radial artery” in combination with “coronary surgery,” “myocardial revascularization,” “coronary artery bypass,” “coronary angiography,” and “percutaneous coronary interventions.” Relevant abstracts were reviewed, and the related articles function was used for all included papers. References for all selected studies were cross-checked. The writing groups selected the most relevant papers according to both methodological and clinical considerations. Observational series were considered only in the absence of data from randomized controlled trials (RCTs). Details of the search are given in Online Figure 1.
Use of the radial artery for transradial procedures
Due to the superficial position and easy compressibility of the RA, TRA has been developed as an alternative to the conventional transfemoral approach (TFA) to reduce the risk of procedure-related vascular complications.
A limitation of TRA is the higher crossover rate than that of the TFA, particularly during the learning curve (2,3). However, the crossover rate declines significantly with operator’s experience (3). Crossovers are generally due to the smaller size, the wide range of anatomic variations, and the high susceptibility to spasm of the RA (Online Table 1) (4).
The assessment of the adequacy of the ulnar collateral circulation has been conventionally considered necessary before TRA. However, recent findings suggest that the patency of the palmar arches is highly dynamic and that the vascular reserve of the hand circulation can be recruited during and after TRA, even in patients with poor collateral circulation at baseline (5). The safety of using the TRA without previous evaluation of the ulnar collateral circulation has been recently shown in a large cohort of patients with acute coronary syndromes (6).
Benefits of using the TRA for angiography and percutaneous interventions
Randomized and observational studies have shown that the use of the TRA significantly reduces vascular access site complications and bleeding compared to the TFA. A meta-analysis of >600,000 patients from both observational and randomized trials comparing TRA and TFA found that radial access was associated with a 78% reduction in major bleeding and an 80% reduction in post-procedure transfusions (9). Three prospective randomized trials comparing TRA with TFA in the setting of acute coronary syndromes consistently showed that TRA reduced major bleeding, major adverse cardiovascular events, and mortality (6,9,10). The reduction in major vascular complications with TRA has been similar for patients undergoing angiography and percutaneous coronary intervention (PCI) (10). Some data suggest that the benefits of the TRA in terms of mortality, but not of bleeding and vascular complications, are significantly influenced by operator experience (6).
The TRA is also associated with benefits in patient satisfaction, catheter laboratory throughput, and costs. It has been shown that patients prefer TRA over TFA (11). The enhanced recovery associated with TRA increases catheter laboratory efficiency and same-day discharge, leading to significant savings for the health system. A large contemporary observational study showed that adoption of TRA can save $3,689 per procedure. Combining TRA and same-day discharge has the potential to save $300 million per year in the United States (12).
TRA in specific patients’ subsets
The advantages of the TRA have been confirmed in the elderly (6). However, elderly patients have more complex vascular anatomy, and the TRA may be more challenging in this population. In case of elderly patients presenting with ST-segment elevation myocardial infarction, the use of TRA has been shown to be associated with a significantly reduced risk of stroke and lower rate of vascular complications and mortality (13).
Adoption of the TRA has been shown to be associated with clinical benefits in patients with chronic renal disease, particularly in terms of reduction of post-procedural acute kidney injury (14). However, the possible need for an upper extremity arteriovenous fistula for dialysis is a possible argument against the use of the TRA in this group of patients.
In patients with a previous CABG, the use of the TRA requires dedicated skills and techniques (15). In the RADIAL-CABG (Radial Versus Femoral Access for Coronary Artery Bypass Graft Angiography and Intervention) trial, the TRA was associated with greater use of contrast, longer procedure time, greater access cross-over, and increased operator exposure to radiation than TFA (16). However, this trial was not conducted in a high-RA use center, and in a meta-analysis of 9 studies in CABG patients, the use of the TRA was associated with lower risk of access-site complications, similar procedural and fluoroscopy times, and higher rate of cross-over than TFA (17).
Caution should be used when using the TRA in patients with severe hemodynamic compromise due to the usually longer delay in initiation of coronary intervention. On the other hand, the reduction in access site complications associated with the TRA can be particularly important for critically ill patients. A recent multicenter study in patients undergoing high-risk PCI found that the use of the TRA was associated with a significant reduction in adverse clinical events compared to the TFA (18). Of note, due to the very high-risk clinical scenario, the possibility of a treatment allocation bias with more experienced operators using the TRA cannot be excluded.
Effect of TRA on the radial artery
In a meta-analysis of 66 studies and >31,000 patients, the incidence of RA occlusion after TRA was found to be 7.7% at 1 day and 5.5% at >7 days after the procedure (19). Of note, late RA occlusion occurring weeks or months after TRA has also been described. RA occlusion is usually asymptomatic due to the dual blood supply to the hand. However, sporadic cases of successful treatment of symptomatic occlusion after TRA have been reported (20).
As intra-arterial thrombosis plays a major role in determining RA occlusion, the use of anticoagulation and modified compression techniques has been shown to significantly reduce its incidence after TRA, with series reporting RA occlusion rate as low as 1% to 2% (19). Distal RA access has also been proposed (21). A list of the possible factors contributing to occlusion is presented in Table 1.
The effect of the TRA on the vascular wall and function of the RA has been recently summarized in a review article (8). Studies using histologic and high-resolution intravascular imaging have shown that the use of the TRA is associated with a high incidence of endothelial damage and a lower but not negligible rate of medial dissection (Figure 1) (8,22). Of note, the vessel wall damage is higher in the distal part of the RA, but it is evident even in the proximal portion of the artery (8). The functional counterpart of the histologic damage is a significant reduction of endothelium-dependent vasodilation and a nonsignificant impairment of endothelium-independent vasodilation as shown by Antonopoulos et al. (23) in a recent meta-analysis. The impairment in vasodilatory function may persist for several months after TRA, and to date, no clear evidence of a return to baseline function with the time exists.
Chronic intimal thickening occurs in a high proportion of patients after TRA, with histologic studies reporting intimal hyperplasia in 60% to 70% of cases (8). RA spasm occurs frequently during TRA. A recent review of the studies reported that the mean incidence of RA spasm after TRA is 14.7% (24). Endothelial dysfunction does not predict RA spasm, whereas artery sheath mismatch is a strong risk factor (25). Reduction of mechanical friction between the sheath and catheter and the arterial wall by hydrophilic coatings and use of pharmacologic vasodilation with nitroglycerin or verapamil or a combination of the 2 agents may significantly reduce RA spasm. Pressure-mediated dilation is a new and promising RA vasodilator strategy (26).
Evaluation and harvesting of the radial artery for CABG
There is no formal agreement on the best method to pre-operatively evaluate the RA for CABG. The adequacy of ulnar collateral flow can be assessed using the clinical Allen test, but many surgeons prefer to rely on a more objective method (Doppler ultrasonography, oximetry, or plethysmography) (27). Many authors also advocate ultrasonography of the artery to evaluate calcification and diameter. Diffuse calcification, diameter <2.0 mm, Raynaud phenomenon, collagen vascular diseases, poor ulnar collateral flow, and major forearm trauma are considered contraindications to use of RA. Caution is recommended in patients with renal failure due to the potential need for dialysis access. In published CABG series, the percentage of RA judged inadequate for use ranges from 5% to 15% (27). Although RA harvesting from the nondominant arm has conventionally been recommended, harvesting from the dominant or bilateral arm is also performed (25). The left RA is the RA of choice for most surgeons as it can be more easily harvested simultaneously with harvesting of the left internal thoracic artery. Endoscopic harvest as opposed to open harvest can also be used with similar clinical and angiographic outcomes (28). The overall incidence of local complications including wound infection or dehiscence and permanent neurological deficits after RA harvesting is <1%, and reports of ischemic hand complications are exceedingly rare (27).
Comparison between the radial artery and the saphenous vein
Three large RCTs have directly compared the patency of RA and SV grafts used for CABG (Table 2). The 2 trials that extended follow-up beyond the first postoperative year found significantly higher patency for the RA. Six meta-analyses summarized the results of these and other smaller comparative RCTs. In all analyses with a mean follow-up >1 year, the use of the RA was associated with a significantly lower incidence of graft failure (Table 3).
All the RCTs had primary angiographic outcomes and were individually underpowered to detect differences in clinical outcomes. A meta-analysis of all published RCTs found significantly lower rate of repeat revascularization and a trend toward reduced incidence of cardiac death and myocardial infarction in the RA group (29). Due to the small number of postoperative events in CABG patients in the modern era, it is likely that even this pooled analysis was underpowered to detect survival differences.
A meta-analysis of the observational reports comparing the RA and the SV is summarized in Figure 2. The use of the RA was associated with similar operative risk and a highly significant 26% relative risk reduction in long-term mortality compared to the use of the SV.
Comparison between the radial artery and the right internal thoracic artery
A large randomized trial showed similar patency for the RA and the right internal thoracic artery (RITA) (30). A network meta-analysis of 9 RCTs confirmed similar patency for the RA and the RITA, despite a nonsignificant trend toward reduced functional occlusion for the RITA (1).
Clinical outcomes between the 2 arterial grafts are more controversial. Observational studies have yielded conflicting results (31,32). A recent meta-analysis of propensity matched studies found a survival advantage with the RITA (33), but an RCT reported equivalent clinical outcomes (30).
Of note, the recently published interim analysis of the ART (Arterial Revascularization Trial) showed no differences in mid-term survival and event-free survival for patients receiving 1 or 2 internal thoracic arteries. However, in a post hoc analysis, the ART investigators showed how the addition of the RA to both groups significantly reduced the rate of major adverse cardiac events (34).
The RA in specific patient subsets
Due to their superior patency and possibly improved survival, additional arterial grafting (using RA or RITA) to supplement the mammary artery to the left anterior descending artery bypass is a Class IIA recommendation in the current European guidelines for patients with reasonable life expectancy undergoing multivessel CABG (35). In the 2011 American College of Cardiology/American Heart Association guidelines, multiarterial grafting receives a Class IIB recommendation (36); in 2016, the Society of Thoracic Surgeons clinical practice guidelines assigned a Class IIA based on a more recent survey of published articles (7).
Use of RA in contrast to use of RITA does not increase the risk of sternal wound complications including mediastinitis, an important consideration due to increasing prevalence of diabetes and obesity in CABG patients.
In diabetics, a large propensity matched study showed similar in-hospital and long-term mortality using the RA or the RITA as the second arterial graft (37). Another study confirmed similar rates of survival for RITA and RA but found that the use of the RITA was associated with increased sternal wound complications (32). A post hoc analysis of the randomized Radial Artery Patency study showed that RA is protective against graft occlusion regardless of diabetes (38), suggesting that RA may be the arterial graft of choice in diabetics (due to their increased risk for sternal complications).
RA use also improves survival in reoperations (39). In this situation, the RA is often the best available conduit due to previous use of the mammary arteries and the SV. Finally, technically, the RA length is more adequate than the RITA to graft distal or multiple targets.
Use of radial artery grafts for CABG after transradial procedures
The only 2 studies that have compared the patency of RAs submitted to TRA to noncatheterized RAs have reported significantly lower patency for TRA-RAs. Kamiya et al. (40) reported 23% occlusion at 30 days for TRA-RAs versus 2% for control RA grafts (p = 0.001). The authors also described a trend toward association between the number of TRAs and the risk of graft occlusion (p = 0.07). In a similar study, Ruzieh et al. (41) reported a 6- to 18-month patency of 59% in the TRA-RA group compared to 78% in the control RA group (p = 0.03).
The current Society of Thoracic Surgeons guidelines suggest an interval of at least 3 months between TRA and use of the RA for CABG, even though they recognize that clinical data are insufficient to designate a safe wait time (7).
However, the attitude of surgeons toward the use of RA grafts after TRA varies considerably. Even among the panelists, some surgeons consider TRA an absolute contraindication to use of RA use, others consider the conduit usable at 3 to 6 months after TRA; and others routinely use the freshly catheterized RA, discarding the most distal portion of the RA containing the puncture site. Noninvasive evaluation of the endothelial function seems an attractive option to preoperatively assess the RA after TRA, but no data on its use have been published to date.
Recommendations for the use of the RA in patients undergoing percutaneous or surgical coronary procedures
As described above, the use of the RA either as vascular access for percutaneous coronary procedures or as conduit for CABG is associated with significant clinical benefits. However, catheterization is associated with RA damage that may ultimately preclude the use of this artery as a conduit for CABG. Hence, every effort should be made to preserve short and long-term RA patency after TRA. Because many patients with coronary artery disease will undergo repeat catheterization and/or PCI over the years, post-TRA RA occlusion has major clinical implications. Beyond the short-term benefit of offering repeat access by the previously used artery, cardiologists should ideally also be concerned about preserving, if possible, an “untouched” RA as a potential conduit if patients require CABG.
Although not yet universally practiced, the use of a combination of smaller catheters, better profiled hydrophilic sheaths, intravenous anticoagulation during TRA procedures, and patent hemostasis with shorter compression time after procedure completion are key to preserve the RA for future use. For cardiologists, it is time to consider the potential additional benefit of the RA not only as preferred access to the coronary circulation but also as a better conduit for CABG, which might impact long-term quality of life as well as survival.
The decision to use the RA at the time of percutaneous procedures or surgery must be individualized and based on the characteristics of the single patient, including the current clinical status, and likely future scenarios.
Based on the current evidence, this panel has elaborated the following recommendations:
1. The TRA should be preferred over the TFA for diagnostic angiography and PCI. This is particularly important in acute coronary syndromes and when intervention is required.
2. When appropriate, the RA should be used in preference to the SV to achieve multiarterial CABG because of its superior patency and potential for improved patient longevity. In particular, the RA may be the preferred second arterial conduit in patients who are at high risk for sternal wound complications.
3. Ideally, an effort should be made to reserve one RA for TRA and the other for potential use as a conduit for CABG. Generally, the use of both RAs for TRA or for CABG is not advisable, unless there are clinical indications or conduits shortage.
4. The laterality of the RA for use is at the discretion of the TRA operator. As most catheter laboratories are set up to use the right RA for TRA and most surgeons prefer to harvest the left RA, it seems reasonable to recommend that, whenever possible, TRA interventions should be performed through the right forearm, and the left arm should be reserved for possible use at surgery.
5. Recommendation 4 may result in a small percentage of cases where the left RA is unusable at surgery due to lack of ulnar compensation. Consequently, in stable patients undergoing angiography, where there is a high likelihood of severe coronary artery disease and limited available conduits for bypass in institutions where the RA is used for CABG, one may consider discussion with the patient regarding alternatives to radial access or TRA on the side with the worst ulnar compensation.
6. Every effort should be made to adopt strategies to minimize RA damage during TRA, including the use of the most distal RA access point, use of miniaturized equipment, optimal intravenous antithrombotic treatment, and patent hemostasis techniques.
7. In patients previously submitted to TRA, the nonpunctured artery should be used for CABG. In situations where the punctured RA is the only available conduit, consideration should be given to the risk of delaying surgery, although the specific time interval required to optimize graft patency is unknown at present.
Future studies are urgently needed in order to, first, identify additional strategies to minimize the risk of radial artery damage during TRA, and second, correlate the extent of RA endothelial damage assessed noninvasively with the patency of RA grafts used for CABG to establish an eventual optimal waiting interval for the use of catheterized RA for CABG.
A flowchart that summarizes, in part, the current recommendations is presented in the Central Illustration.
Dr. Burzotta has received speakers and consultant fees from Abbott and St. Jude Medical. Dr. Rao has served as a consultant for Medtronic and Terumo. Dr. Trani has received speaker fees from Medtronic, Abbott, Abiomed, and Terumo; and consultant fees from Biotronik. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose. Drs. Gaudino and Burzotta contributed equally to this work and are joint first authors. Michael Mack, MD, served as Guest Editor for this paper.
- Abbreviations and Acronyms
- coronary artery bypass operations
- coronary artery disease
- percutaneous coronary intervention
- radial artery
- randomized controlled trial
- right internal thoracic artery
- saphenous vein
- transfemoral approach
- transradial access
- Received October 31, 2017.
- Revision received January 4, 2018.
- Accepted January 5, 2018.
- 2018 American College of Cardiology Foundation
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