Total Arterial Coronary Revascularization Research Articles

Application of the radial artery after angiography in patients undergoing total arterial coronary revascularization

ObjectiveThere is growing evidence supporting the utilization of the radial artery as a secondary arterial graft in coronary artery bypass grafting (CABG) surgery. However, debates continue over the recovery period of the radial artery following angiography. This study aims to evaluate the clinical outcomes and experiences related to the use of the radial artery post-angiography in total arterial coronary revascularization.MethodsA retrospective analysis was performed on data from patients who underwent total arterial CABG surgery at the University of Hong Kong Shenzhen Hospital from July 1, 2020, to September 30, 2022. Preoperative assessments included ultrasound evaluations of radial artery blood flow, diameter, intimal integrity, and the Allen test. Additionally, pathological examinations of the distal radial artery and coronary artery CT angiography were conducted, along with postoperative follow-up to assess the safety and efficacy of using the radial artery in patients undergoing total arterial CABG.ResultsA total of 117 patients, compromising 102 males and 15 females with an average age of 60.0 ± 10.0 years, underwent total arterial CABG. The internal mammary artery was used in situ in 108 cases, while in 4 cases, it was grafted to the ascending aorta due to length limitations. Bilateral radial arteries were utilized in 88 patients, and bilateral internal mammary arteries in 4 patients. Anastomoses of the proximal radial arteries to the proximal ascending aorta included 42 cases using distal T-anastomosis and 4 using sequential grafts. The interval between bypass surgery and coronary angiography ranged from 7 to 14 days. Pathological examination revealed intact intima and continuous elastic membranes with no significant inflammatory infiltration or hyperplastic lumen stenosis in the radial arteries. There were no hospital deaths, 3 cases of perioperative cerebral infarction, 1 secondary thoracotomy for hemorrhage control, 21 instances of intra-aortic balloon pump (IABP) assistance, and 2 cases of poor wound healing that improved following debridement. CT angiography performed 2 weeks post-surgery showed no internal mammary artery occlusions, but 4 radial artery occlusions were noted.ConclusionUltrasound may be used within 2 weeks post-angiography to assess the recovery of the radial artery in some patients. Radial arteries with intact intima may be considered in conjunction with the internal mammary artery for total arterial coronary CABG. However, long-term outcomes of these grafts require further validation through larger prospective studies.

Total arterial revascularization using robot assisted minimally invasive coronary artery bypass: an Indian experience.

The aim of this study is to analyze the early outcomes of Total Arterial Revascularization using Robot Assisted Minimally Invasive Coronary Artery Bypass at our center between June 2019 and January 2023. This is a retrospective analysis of 195 patients who underwent Total Arterial Coronary Revascularization through Robot Assisted Minimally Invasive Coronary Artery Bypass procedure (RA-CABG) during the period of June 2019 and January 2023 in a quaternary care center in India. Primary outcome variables were in-hospital and 30-day mortality. Secondary outcome variables included duration of surgery, length of intensive care unit (ICU) stay, in-hospital stay and perioperative morbidity. The entire patient population was divided into two groups for a subgroup analysis based on when the surgery was conducted i.e. the years since the robotic program was begun at our institution with 81 patients in group I (2019-2021), and 114 patients in group II (2022-2023). 195 patients [88.7% male, mean age of 61.34 ± 9.58years] underwent RA-CABG during the 5-year period (2019-2023) by a single experienced surgeon and his team. Conversion to larger thoracic incisions was required in 5 cases (2.59%). In-hospital and 30-day mortality was 1.02% each. The average length of ICU stay and hospital stay were 2.82 ± 1.17days and 5.84 ± 1.71days respectively. The duration of ICU stay correlated with the number of internal mammary artery grafts procured (p = 0.0022). Median duration of follow-up was 11months. Overall mortality was 3.62% and cardiac related mortality was 2.07%, and 5 patients (2.59%) underwent percutaneous coronary intervention. Results of the sub-group analysis revealed a statistically significant difference between the groups in terms of number of internal mammary artery grafts procured (p = 0.010), need for transfusions (p = 0.00031), ICU stay (p = 0.0005) and in-hospital stay (p = 0.0006). Total Arterial Coronary Revascularization through RA-CABG is a viable procedure in select patients. An experienced surgeon and team are required. Further studies in the form of randomized trials with long term follow-up are required to establish the overall utility, effectiveness and benefits to the patients.

Application of radial artery in total arterial coronary revascularization in elderly patients

To summarize the application experience and clinical effect of radial artery in total arterial coronary revascularization (TAR) in elderly patients. Retrospectively analyzed the clinical data of patients who underwent TAR at the University of Hong Kong Shenzhen Hospital from July 1, 2020 to May 30, 2022. Patients were divided into ≥ 65-year-old group and < 65-year-old group according to age. The radial artery blood flow, diameter, intimal integrity and Allen test were evaluated by ultrasound before operation. The distal ends of radial artery were collected for pathological examination during operation. Coronary artery CT angiography (CTA) was examined postoperatively and follow up. The safety and reliability of ultrasonic assessment of radial artery and application of radial artery in elderly patients with TAR were summarized and analyzed. A total of 101 patients received TAR, including 35 cases aged ≥ 65 years old, 66 cases aged < 65 years old; 78 cases used bilateral radial arteries, and 23 cases used unilateral radial arteries. 4 cases of bilateral internal mammary arteries. All the proximal ends of the radial artery were anastomosed to the proximal end of the ascending aorta, 34 cases were performed of "Y" grafts, and 4 cases were sequential anastomoses. There was no in-hospital death and perioperative cardiovascular events. Perioperative cerebral infarction occurred in 3 patients. 1 patients was reoperated for bleeding. Intra-aortic balloon pump (IABP) assistance was used in 21 patients. Poor wound healing occurred in 2 cases and healed well after debridement. Follow-up of 2 to 20 months after discharge showed no internal mammary artery occlusion and 4 radial artery occlusions; no major adverse cardiovascular and cerebrovascular event (MACCE) occurred, and the survival rate was 100%. There was no significant difference in the above perioperative complications and follow-up endpoints between the two age groups. By adjusting the order of bypass anastomosis and optimizing the preoperative evaluation method, radial artery combined with internal mammary artery can obtain better outcome early in TAR, and can be safely and reliably applied to elderly patients.

Internal thoracic artery on the aorta: A simple radial connection.

Although performing total arterial coronary artery bypass revascularisation, using internal thoracic arteries as in situ grafts is not always feasible. The implantation of an internal thoracic artery on the aorta could be necessary, in a situation rarely planned preoperatively. Herein, we describe a simple and original way to perform this anastomosis. A 2-cm length of extra radial artery graft ended by a clip is anastomosed to the aorta in a standard fashion. The internal thoracic artery is then sown on the radial dome. We obtain a wide arterial anastomotic chamber using a standard technique, safe and easily reproducible.

Impact of transit-time flow measurement on early postoperative outcomes in total arterial coronary revascularization with internal thoracic arteries: a propensity score analysis on 910 patients.

The aim of this study was to evaluate the impact of transit-time flow measurement (TTFM) on early postoperative outcomes in total arterial coronary revascularization. A single-centre retrospective analysis was conducted on 910 patients undergoing isolated total arterial coronary artery bypass grafting with internal thoracic arteries (ITAs) at our institution, between January 2017 and February 2020. Complete arterial revascularization with bilateral ITAs with a Y-configuration, or single ITA, was planned for all patients. According to the surgeon preference, TTFM was assessed in 430 patients (TTFM group). They were compared with 480 patients without TTFM assessment (no TTFM group). Primary end point was the occurrence of in-hospital major cardiac adverse events (MACE). A propensity score analysis with an inverse probability weighting approach was performed to control for selection bias. TTFM was associated with longer cardiopulmonary bypass times (76.0 [62.0; 91.2] vs 79.0 [65.0; 94.0] min, P = 0.042). Six (1.4%) patients in the TTFM group versus no patient in the no TTFM group underwent intraoperative graft revision because of unsatisfying flow values (P = 0.011). MACE were significantly lower in the TTFM group (14, 3.3%) than in the no TTFM group (33, 6.9%, P = 0.014). At crude regression, TTFM was protective against MACE occurrence (odds ratios 0.46, 95% confidence interval 0.23-0.85, P = 0.016). Inverse probability weighting adjustment did not significantly displace P-values and odds ratios for MACE occurrence in the TTFM group 0.44, 95% confidence interval 0.28-0.69, P < 0.001. Even if associated with longer cardiopulmonary bypass times, intraoperative graft flow measurement with TTFM reduces MACE occurrence and it should be recommended for graft evaluation in arterial coronary artery bypass grafting surgery.

Transient time flow measurement in total arterial coronary revascularisation with internal thoracic arteries. Three years’ experience in 433 patients

Intraoperative graft flow measurement in coronary artery bypass grafting (CABG) is recommended, but its clinical impact is still controversial. We evaluated the effect of Transient Time Flow Measurement (TTFM) on Major Cardiac Adverse Events (MACE) in CABG surgery. Between January 2017 and February 2020, 959 patients underwent total arterial CABG with internal thoracic arteries (ITAs). Thirty-four patients with critical preoperative status according Euroscore II definition or redo procedures were excluded from the analysis. According to the surgeon preference, TTFM were assessed in 433 patients (TTFM) with Medistim system ( Fig. 1 ). They were compared with 492 patients without TTFM assessment (No TTFM). Complete arterial revascularisation with single or bilateral ITAs with a Y-configuration was planned for all patients. Patients’ data were extracted from the French Society of Thoracic and Cardiovascular Surgery database (EPICARD). Primary end-point was the occurrence of MACE, including in-hospital cardiac mortality, perioperative myocardial infarction, cardiac arrest and the need for extra-corporeal membrane oxygenation (ECMO). Preoperative characteristics, operative data and postoperative outcomes are resumed in Table 1 . TTFM is associated with longer cardio-pulmonary bypass (CPB) times, because of supplementary time needed for measurement (82 ± 24 vs. 78 ± 25 min., P = 0.023). Five patients in TTFM group underwent graft revision because of unsatisfying flow values. MACE were significantly lower in TTFM group (2.1% vs. 5.7%, P < 0.01). At multivariate analysis, TTFM was protective against MACE occurrence (OR 0.353, 95% CI 0.146–0.770, P = 0.013). Other independent risk factors for MACE occurrence were cross clamp time (OR 1.18, 95% CI 1.03–1.35, P = 0.016) and Euroscore II (OR 1.21, 95% CI 1.13–1.29, P < 0.001). TTFM reduces MACE occurrence and it should be mandatory for graft evaluation in coronary artery surgery.

Branched internal mammary conduit permits non-sequenced total arterial revascularization.

Recent trends in cardiac surgery have encouraged total arterial coronary revascularization, citing advantages in long-term patency and overall mortality. Often relying on sequenced, composite, and free-graft strategies, total arterial coronary revascularization is limited by conduit availability and surgical complexity. We present the use of bilateral internal mammary artery grafts to achieve nonsequential 3-vessel total arterial coronary revascularization using the preserved distal bifurcation of the right internal mammary artery. Utilization of distal internal mammary artery branches should be considered a viable strategy in select patients and can broaden the opportunities for total arterial coronary revascularization in patients with multivessel coronary disease.

Radial Artery vs Bilateral Mammary Composite Y Coronary Artery Grafting: 15-Year Outcomes

Total arterial coronary revascularization for three coronary territory disease can be achieved with a second arterial conduit joined to the left internal mammary artery as a Y graft, by using either a radial artery (RAY) or a second mammary artery (BIMAY). Patients undergoing total arterial revascularization for three coronary territory disease were identifiedfrom two cardiac surgical databases (in Sydney and Melbourne, Australia) using Society of Thoracic Surgeons-based definitions. BIMAY-treated patients underwentsurgery between 1994 and 2009, mostly usingan age-limited protocol, whereas RAY-treated patientsunderwent surgery between 1996 and 2003 without age limits. All-cause mortality data were acquiredfrom the national death registry, and survivalwas estimated by the Kaplan-Meier method. Propensity score matching was performed using 13 variables. Given the age imbalance between the groups, theprimary comparison was performed for age 66 years or younger. Overall, 1896 patients underwent RAY procedures, and 720 patients underwent BIMAY operations. Older age at surgery was the strongest independent predictor of mortality, with a hazard ratio of 2.06, and a 95% confidence interval of 1.93, 2.22 (P < .001). After propensity score matching, we identified 299 pairs of patients 66 years of age or younger with no preoperative or operative differences and similar ages at surgery: RAY 56.4 ± 7.0 years of age vs BIMAY 56.4 ± 6.8 years of age (P= .96). The RAY group had 4.0 ± 0.9 grafts, and the BIMAY group had 3.9 ± 0.9 grafts (P= .814). All-cause mortality was not different, with the proportion surviving at 15 years at 74.9% for the RAY group vs 76.2% for the BIMAY group (P= .211). Survival was not different between the RAY and BIMAY groups for total arterial revascularization of three coronary territory bypass grafting.

RARAY Operation: Operative Description and Early Results for Achieving Total Arterial Coronary Revascularisation

Total arterial revascularisation may prolong postoperative survival following coronary surgery due to avoidance of late saphenous vein graft (SVG) failure leading to ischaemic cardiac events. The left internal mammary artery (LIMA) is routinely used for CABG but harvest may adversely affect lung function and reduce sternal vascular supply. Early experience of a novel reconstruction with exclusive reliance on two radial arteries (RA) joined as a Y graft (RARAY) is presented. One RA is anastomosed to the ascending aorta and used to revascularise the left anterior descending artery coronary territory; and a second RA is joined to the first 4-6 cm from the origin, approximating the lateral border of the pulmonary artery and used to revascularise the circumflex and right coronary territories. No LIMA is used. The radial artery was harvested open with diathermy and metal clips and since 2008, all patients received intravenous vasoconstrictors from the commencement of the anaesthetic. From 2002 to 2019, 28 patients underwent RARAY for specific indications of prior use or reasons to avoid LIMA harvest, preservation of lung function, minimisation of bleeding risk from antiplatelet agents and extra length of RA to graft distal coronary targets beyond usual reach for LIMA. There was no RA spasm, no in-hospital death and no patient returned with symptoms of angina. The early experience of the RARAY operation for three coronary territory revascularisations are satisfactory.

Early clinical outcomes of minimally invasive coronary surgery-total arterial coronary revascularization

Objective: To summarize the early experience and clinical value of minimally invasive coronary surgery-total arterial coronary revascularization (MICS-TACR) through the left anterior small incision. Methods: Between May 2015 and June 2018, a total of 31 consecutive cases [21 males and 10 females, aged (63.2±9.3) years] in Peking University Third Hospital who were performed MICS-TACR with bilateral internal mammary artery and radial artery were enrolled. Meanwhile, 1 489 cases of conventional median sternal incision off-pump coronary artery bypass grafting (OPCABG) were matched as control group. According to exclusion criteria and matching score, 90 cases [55 males and 35 females, aged (63.8±9.5) years] were selected as the control group, and the perioperative data of the two groups were compared. All patients in MICS-TACR group underwent postoperative angiography and the graft patency was evaluated. Results: There were no statistically significant differences in baseline data between the two groups. The perioperative blood transfusion of MICS-TACR group was less than control group [0(0,0) U vs 0(0,4) U, P=0.003]. There were no statistically significant differences in operative mortality, intraoperative and postoperative intra-aortic balloon pump (IABP) and extracorporeal membrane oxygenation (ECMO) use, re-operation rate, perioperative major adverse cardiac and cerebrovascular events (MACCE), new-onset renal failure, atrial fibrillation, and multiple organ failure between the two groups. Postoperative angiography showed that there was no significant difference in the patency rate between the MICS-TACR group and control group(all P>0.05). Conclusion: Total arterial coronary revascularization can be successfully accomplished under the left anterior small incision, and the early clinical outcome is satisfied.

Does the Use of Saphenous Vein Graft in Coronary Surgery Affect Patient Survival at Different Ages?

Purpose: Although it is perceived that total arterial coronary revascularisation (TAR) leads to improved survival, it remains a common perception that older patients may not benefit as their life expectancy is shorter.

Total Arterial Coronary Revascularisation is Associated with Lower Postoperative Major Adverse Cardiac and Cerebral Events

Introduction: Total arterial revascularisation (TAR) with internal mammary artery (IMA) and radial artery (RA) may be associated better survival and freedom from major adverse cardiac and cerebral events (MACCE) compared to the standard approached of coronary artery bypass grafts (CABG) with single IMA and supplementary saphenous venous grafts (SIMA+SVG). Methods: Patients with primary CABG at Royal Melbourne Hospital, 1996-2004 were contacted via telephone or mail to assess MACCE (myocardial infarction (MI), stent insertion (PCI), redo CABG, and stroke). Only those had TAR or SIMA+SVG with postoperative duration > 10 years were included. To reduce treatment selection bias, 1 to 1 nearest-neighbour propensity score matching (PSM) with random matching with calliper 0.2*SD were applied. Preoperative covariates were smoking, diabetes, hypercholesterolemia, hypertension, obesity, any concomitant heart valve disease, positive family history and renal failure. Results: 215 patients completed follow up data, TAR (170) and SIMA+SVG (45). Age at follow up was 77.3±9.9 yr with 82.5% males, 93% isolated CABG. 15 patients were excluded (redo CABG = 12, incomplete preoperative data = 3). Two groups were formed (TAR (156) and SIMA+SVG (44), and PSM yielded 41 in each group with. Balance covariates were achieved with absolute standardised difference < 0.25. The proportion of patients with at least one MACCE event was lower for TAR than for SIMA+SVG, 12 vs. 39%, p=0.010. MACCE subgroup data for TAR vs. SIMA+SVG was: MI 2 vs. 12%, PCI 7 vs. 24%, redo cardiac surgery 0 vs. 0%, stroke 5 vs. 10%. Conclusion: TAR has a lower MACCE compared to SIMA+SVG.

Multivessel Total Arterial Coronary Revascularisation is Associated with Lower Postoperative Major Adverse Cardiac and Cerebral Events

Multivessel Total Arterial Coronary Revascularisation is Associated with Lower Postoperative Major Adverse Cardiac and Cerebral Events

Total arterial coronary revascularization

Arterial coronary grafts can be used in the majority of patients and have better patencies than saphenous vein grafts (SVGs), resulting in excellent perioperative and superior long-term outcomes. Barriers to their extensive use include potential for trauma and spasm, extra-operating time, unfamiliarity, concerns over hypoperfusion and deep sternal wound infection in patients in whom bilateral internal thoracic arteries are used-especially diabetics. This presentation addresses these concerns with particular attention to the radial artery, and skeletonized right internal thoracic artery harvest and construction of the proximal anastomoses of these grafts to the ascending thoracic aorta. The facile handling of these grafts and techniques identical to SVG grafting are emphasized. Avoidance of competitive flow and the importance of spasm prophylaxis cannot be overstated. Arterial grafts have patencies >90% at 10 years (SVG 50-60% at 10 years) and once functioning normally, remain free of atheroma. Long-term results are excellent, especially freedom from recurrent cardiac events and reoperations, even in patients with significant preoperative comorbidities such as diabetes and renal dysfunction. Depending on age, long-term survival is between 85 and 90% at 10 years and 75 and 80% at 15 years, and is always better than for one arterial graft plus SVG in all long-term risk-adjusted or propensity-matched studies.

Transapical aortic valve implantation and minimally invasive off-pump bypass surgery

Transcatheter aortic valve implantation (TAVI) has gained increasing popularity for high-risk patients with symptomatic aortic valve stenosis. A concomitant coronary artery disease leads to a complicated management and an increased perioperative risk. This case report describes the successful total arterial coronary revascularization of the left anterior descending and the left marginal branch of the circumflex artery utilizing the left internal mammary artery (LIMA) and left radial artery in off-pump technique in combination with the transapical transcatheter aortic valve implantation via minimally invasive anterolateral access in the fifth intercostal space.

Short term outcomes of total arterial coronary revascularization in patients above 65 years: a propensity score analysis

BackgroundDespite the advantages of bilateral mammary coronary revascularization, many surgeons are still restricting this technique to the young patients. The objective of this study is to demonstrate the safety and potential advantages of bilateral mammary coronary revascularization in patients older than 65 years.MethodsGroup I included 415 patients older than 65 years with exclusively bilateral mammary revascularization. Using a propensity score we selected 389 patients (group II) in whom coronary bypass operations were performed using the left internal mammary artery and the great saphenous vein.ResultsThe incidence of postoperative stroke was higher in group II (1.5% vs. 0%, P = 0.0111). The amount of postoperative blood loss was higher in group I (908 ± 757 ml vs. 800 ± 713 ml, P = 0.0405). There were no other postoperative differences between both groups.ConclusionBilateral internal mammary artery revascularization can be safely performed in patients older than 65 years. T-graft configuration without aortic anastomosis is particularly beneficial in this age group since it avoids aortic manipulation, which is an important risk factor for postoperative stroke.

The Role of Intravenous Dihydropyridine Calcium Channel Blockers in the Perioperative Management of Patients Undergoing Coronary Artery Bypass Surgery

The pharmacology characteristics of dihydropyridine calcium channel blockers (CCB) make them an attractive antihypertensive medication for use in the perioperative setting of coronary artery bypass graft (CABG) surgery. They lack the negative inotropic, negative chronotropic, and negative bathmotropic effects of phenylalkylamine and benzothiazepine CCB that limit the use in patients with heart failure or patients with bradyarrythmias. With the aging population and significant rise in the prevalence of heart failure, the use of dihydropyridine CCB as antihypertensive medication after CABG surgery has become more common. Furthermore, intravenous dihydropyridine CCB are being used in the perioperative setting as vasodilatory agents after radial artery harvesting for total arterial coronary revascularization. We review the pharmacological effects of intravenous dihydropyridine CCB, analyze the literature, and comment on the consequences in modern clinical practice.

Total Arterial Coronary Revascularization Using Arterial Bypass Circle With Multiple Inflows

Coronary artery bypass techniques, currently applied to maximize the benefits of multiple arterial coronary conduits, render the newly constructed myocardial flow dependent on a single source "inflow" of blood. We describe a technique for total arterial coronary revascularization with multiple inflows; the distal end of the pedicled right internal thoracic artery is anastomosed to the distal end of a free radial artery, and the other end of the radial artery is then connected to the ascending aorta. This vascular circle, passed in a retro-cardiac fashion, is used to revascularize the inferio-lateral surface of the heart using multiple side-to-side anastomoses. The "sacred" left internal thoracic artery is reserved to revascularize the anterior wall of the myocardium, independent of the arterial circle.

Total arterial revascularisation in left ventricular dysfunction

The feasibility and safety of total arterial coronary revascularization with 2 arterial conduits in patients with impaired left ventricular function was evaluated. Data were prospectively collected on all patients with multiple vessel discase and moderately or severely impaired left ventricular function, who underwent coronary surgery with the intention of total arterial revascularization with 2 conduits between March 1995 and August 2002. One hundred and seventy-nine patients were included in the study. Acute coronary insufficiency was present in 3 patients and 43 had unstable angina. Severe left ventricular impairment was present in 29 patients. There were 17 redo operations including 3 redo-redo procedures. Eighty-two percent of patients had a Y graft configuration from the left internal mammary artery (right internal mammary artery 40.8%, radial artery 33.5%, other 7.8%). The perioperative mortality was 2.2%, myocardial infarction 1.7% and stroke 0.6%. Total arterial revascularization in patients with ischaemic left ventricular dysfunction can be safely performed with 2 arterial conduits. The radial artery provides conduit length greater than the right internal mammary artery and allows full revascularization despite left ventricular dilatation.

Duplex ultrasonography predicts safety of radial artery harvest in the presence of an abnormal Allen test

Background The Allen test is commonly used to assess collateral hand circulation before radial artery harvest for coronary artery bypass grafting. However there is no consensus as to whether an abnormal Allen test is an absolute or relative contraindication to radial artery harvesting. We assessed the safety of harvesting the radial artery using arterial duplex ultrasonography in patients with an abnormal Allen test. Methods Two hundred and eighty-seven consecutive patients scheduled for total arterial coronary revascularisation underwent preoperative Allen tests over a 34-month period. Patients with an abnormal Allen test underwent duplex ultrasonography preoperatively to assess the adequacy of the ulnar collateral supply and the suitability of the radial artery for harvesting. Results Two hundred and forty-four patients (85%) had a normal left Allen test and proceeded directly to radial artery harvest. Forty-three patients (15%) with an abnormal left Allen test underwent duplex ultrasonography scans and of those, 5 patients had an abnormal scan. These patients underwent scanning of the contralateral forearm. Three patients had a normal right forearm arterial duplex scan and the right radial artery was harvested. The mean diameter of the radial and ulnar arteries was not significantly different between the patients with normal and abnormal duplex ultrasonograms. There were no ischemic hand complications in this series. Conclusions The Allen test is a quick, easy, and reliable screening test before radial artery harvesting in the majority of patients. Duplex ultrasonography predicts safe radial artery harvest in the majority of patients with an abnormal Allen test.