Angiographic Evaluation of the Radial Artery Diameter in Patients Who Underwent Coronary Angiography or Coronary Intervention

Abstract: Objectives. The aim of this study was to determine the radial artery diameter of patients through angiography and evaluate the feasibility of using wider sheaths for radial interventions. In addition, any parameters that could affect the radial artery diameter were also evaluated. Background. The radial artery is a suitable, beneficial route for coronary procedures and is considered a good alternative to transfemoral access. However, a small radial artery diameter may make complicated coronary and peripheral procedures even more difficult. Therefore, an evaluation of the radial artery diameter may help the interventional cardiologist to select the instruments and techniques that are the most appropriate for the patient. Methods. Radial artery diameters were calculated in 93 consecutive patients who underwent a transradial coronary procedure along with simultaneous radial angiography, and the anthropometric parameters that might affect the diameter and the association between vessel diameter and pain experienced by the patient during sheath removal were investigated. Results. A total of 97 patients (69 males [71.1%]; 28 females [28.9%]) between 30-89 years of age (mean age, 59.0 ± 10.6 years) were included in the study. Four patients were excluded due to the failure of the radial procedure. The radial artery diameters were measured angiographically in the remaining 93 patients, and the procedural success rate was 95.8%. The mean radial artery diameters were 2.3 ± 0.38 mm in males, 2.1 ± 0.42 mm in females, and 2.3 ± 0.40 mm for the entire study population. Body weight and distal and proximal wrist diameters showed positive and significant correlations with the radial artery diameter (P=.025, P=.013, and P=.032, respectively). Conclusion. In this cross-sectional study, since the mean radial artery diameter was 2.3 ± 0.40 mm, the coronary procedures performed via the radial route can be deemed successful. Moreover, we found no independent predictors of radial artery diameter. Among the patients, 74% had coronary artery diameters of 6 Fr or larger. As long as the ulnar collateral circulation is sufficient, the transradial procedure can be safely performed without considering any other anthropometric parameters.

J INVASIVE CARDIOL 2013;25(7):353-357

Key words: radial artery diameter, transradial intervention, coronary procedures

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Percutaneous coronary intervention (PCI) can be performed by femoral, brachial, or radial routes. The femoral route is the most conventional approach and is widely used throughout the world. However, in some studies, the femoral approach has been reported to be associated with vascular and bleeding complications that have been known to reach a rate of 7.4%.^1-4

With the eventual decrease in the incidence of ischemic events following PCIs, the risk of bleeding during the procedures has gained more importance. A hematoma at the intervention site requiring a blood transfusion is associated with an increase in the risk of adverse events, including mortality. Even with aggressive antithrombotic treatment regimens, in the presence of an effective ulnar collateral circulation, there are more complications related to access sites following the transfemoral approach than with the transradial approach. 

Following its introduction in 1989, the transradial approach began to be considered as an alternative to the transfemoral approach for diagnostic and interventional coronary procedures.⁵ This approach is associated with improved patient comfort, earlier ambulation, lack of bed confinement, and improved postprocedural physical and social functions; hence, it is preferred by patients.⁶ Moreover, compared to the transfemoral approach, the transradial method reduces the hospitalization period while also limiting complications associated with bleeding and lowering the cost of treatment.^7-9

Diagnostic and therapeutic PCIs have gradually replaced coronary bypass surgery, and this type of procedure continues to grow in popularity. Thus, the methods chosen for PCIs are gaining more importance every day. The advantages of the transradial approach outweigh its disadvantages; however, small radial artery diameters may make complex coronary and peripheral procedures more difficult. For this reason, estimating the radial artery diameters may help the interventional cardiologist in the selection of the most appropriate instruments and techniques. The aims of this study were to angiographically measure radial artery diameters, investigate the feasibility of using wider sheaths during radial interventions, examine the relationship between the radial artery diameter and pain perception during the removal of the radial sheath, and determine the parameters that affect the radial artery diameter.

Methods

Patient selection. Initially, a total of 97 patients who were admitted to the Cardiology Department of Gazi University between March and December 2009 and who underwent a diagnostic or interventional coronary procedure by the radial approach were considered for inclusion in the study. From these cases, we excluded 4 patients in whom a transradial approach was not successful, which left 93 patients in the study. The procedures were performed with the consent of the local ethics committee and according to the criteria put forth in the Declaration of Helsinki. 

Body weight and height were measured using standard methods and devices. Wrist diameters were recorded in millimeters at the level of the patient’s wrist (distal measurement) and 3 cm upward (proximal measurement). In addition, each patient was evaluated with regard to major cardiovascular risk factors. 

The pain perceived by each patient during sheath removal was evaluated by a previously described pain rating scale.¹⁰ Namely, the patient was asked to score their perceived pain on a scale between 0 and 10, with 0 representing no pain and 10 corresponding to the most severe pain. The patients were classified into three separate groups according to these pain levels. The first group included patients with scores of 0 (no pain). Another had patients with scores between 1 and 6 (mild-to-moderate pain), and the last group comprised subjects with scores between 7 and 10 (severe pain).

Radial angiography procedure. Allen’s test and simultaneous pulse oximetry plethysmography were performed for each patient before the transradial coronary angiography, and radial intervention was considered only in patients with no pathological findings. The transradial procedure was performed under analgesia. Before the arterial puncture, local anesthesia was administered with 2-3 mL of 2% lidocaine. Radial artery puncture was made with a 19 gauge needle at an angle of 25-30°, 1-2 cm proximal to the stiloid process or 2-3 cm proximal to the wrist line. The sheath length was 11 cm, and Cordis Radial Source transradial kits (Cordis Corporation) with 0.021˝ guidewires were used in the procedures. Upon periprocedural bleeding, a guidewire was inserted through the gauge needle. Then the sheath and the dilator in it were introduced after a small percutaneous incision. Following the removal of the dilator and guidewire, a mixture consisting of 200 µg nitroglycerin, 2.5 mg verapamil, and 5000 IU heparin prepared in 20 mL of saline was administered. To prevent spasm and pain during sheath removal, 200 µg nitroglycerin and 2.5 mg verapamil in 10 mL of saline was also injected. Radial angiography was performed using contrast media diluted in saline. In patients who underwent a diagnostic coronary angiography, the sheath was removed at the end of the procedure. However, for those who underwent PCI, sheath removal was performed 30 minutes after the procedure in order to perform the necessary intervention in cases of acute stenosis that required additional imaging.

Hemostatic control was accomplished with the use of appropriately-sized sponge rolls and hemostatic RADstat radial artery compression devices (Merit Medical Systems, Inc). Patients who underwent diagnostic transradial coronary angiography were followed up for 3 hours via hemostatic compression devices before discharge. Those who underwent PCI were followed for 1 day in the hospital and discharged afterward, depending on their clinical status.

The patients’ radial artery diameters were measured by the Toshiba Rotanode DSRX-T7444GDS angiography high-power x-ray tube using a specially designed measurement program that took the radial sheath diameter as a reference at 5 cm distal to the sheath end.

Statistical analysis. Statistical analysis of the data was performed using the Statistical Package for Social Science for Windows version 11.5 software package (SPSS Inc). For descriptive statistics, mean ± standard deviation or median values (minimum-maximum) were used for continuous variables. Categorical variables were represented by the number of cases (n) and percentages (%). Student’s t-test was used to assess statistical significances in the mean vessel diameters between groups when there were two independent groups, and one-way analysis of variance (ANOVA) was used when there were more than two groups. Correlations between continuous variables were evaluated by Pearson’s correlation coefficient or Spearman’s rank correlation coefficient. Regression coefficients and 95% confidence intervals were calculated for each variable, and a P-value of <.05 was considered to be statistically significant.

Results

A total of 97 patients (69 males, 28 females) between 30 and 89 years of age (mean age, 59.0 ± 10.6 years) were randomized. Four patients were excluded due to the failure of the radial procedure. The radial artery diameters were angiographically measured in the remaining 93 patients, and the procedural success rate was 95.8%. In case of failure through the radial approach, the coronary procedure was performed via the femoral route. The mean radial artery diameters were calculated as 2.3 ± 0.38 mm in males, 2.1 ± 0.42 mm in females, and 2.3 ± 0.40 mm for the whole study population. The demographic features of the patients are shown in Table 1, and the anthropometric characteristics and laboratory data are summarized in Table 2. 

The procedure required the use of 4 Fr catheters in 3 patients, 5 Fr catheters in 56 patients, and 6 Fr catheters in 34 patients. The right radial artery was selected in only 3 patients, and the left radial artery was used in the remaining cases. Postprocedural pain during sheath removal was evaluated, and 11 patients suffered from severe pain (Table 3). The radial artery diameter was 7 Fr or greater in 53.7% of the males and 34.6% of the female patients. There was a statistically significant difference between the men and women when the mean radial artery diameters were compared, with men having the larger diameters (P=.034) (Table 4). The diameters were similar in hypertensive and normotensive patients and in diabetic and non-diabetic patients. Family history and smoking status were  also among the variables that did not significantly alter the radial artery diameter (Table 4).

There were also no significant correlations between age, height, body mass index (BMI), total cholesterol, fasting glucose, and uric acid levels with regard to radial artery diameter. However, body weight along with the distal and proximal wrist diameters showed positive and significant correlations (Table 5).

Univariate statistical evaluations had suggested that gender and body weight along with distal and proximal wrist diameters could be associated with radial artery diameter. Similarly, multivariate analyses had also suggested that height could be involved. Therefore, these variables were chosen as candidates for multivariate linear regression analyses, and this demonstrated that none of these variables significantly affect radial artery diameter (Table 6).

The mean ages between the groups classified according to postprocedural pain level during sheath removal were not statistically significant (P=.919). Additionally, pain level distributions were not associated with hypertension, diabetes mellitus (DM), smoking status, or catheter size. Furthermore, the mean ages between the groups as classified according to postprocedural pain level during sheath removal were similar (Table 7).

Discussion

Atherosclerotic coronary artery disease continues to be the most frequent cause of mortality. However, the development of PCI methods and techniques in the diagnosis and treatment of coronary artery diseases has significantly reduced the mortality rate. The continued increase in the number of diagnostic and therapeutic PCIs has brought about discussions involving access sites. The transradial approach, which has many advantages, is commonly used nowadays. However, a consensus has been formed that in patients with a low BMI (<50 kg, <150 cm), a small radial artery diameter poses a problem in radial artery interventions, with complications such as radial spasm being more frequent among these patients.

The aim of our study was to measure the radial artery diameter through the use of angiography and evaluate the possible determinants, including BMI, body weight, height, and wrist diameter.

As far as we know, no reports exist in the medical literature concerning the factors that determine radial artery diameter. However, it is possible to find many reports on the determinants of coronary artery diameter.^11-21 In a study in which three different age groups of patients with arteriographically-defined normal coronary arteries were examined, the coronary vessel cross-sectional area and total coronary cross-sectional area were shown to increase with regional myocardial mass and decrease with age.¹¹ The decrease with age was thought to be associated with less physical activity. The prognosis for women after a myocardial infarction or coronary revascularization is poor, and this could be a result of women’s smaller coronary arteries. However, it is possible that other factors may also be involved. This hypothesis was tested in a study conducted via intravascular ultrasonography in which the effect of coronary artery dimensions was assessed independently from body mass. The results showed an association between gender and coronary artery dimensions both by univariate and multivariate regression analyses.¹² Coronary artery diameter is known to be inversely associated with perioperative mortality related to coronary artery bypass grafting (CABG), and this association is believed to be responsible for the increased risk among women and smaller people. To test this hypothesis, O’Connor et al conducted a study on 1325 patients and observed that coronary artery diameter increased with body surface area, BMI, height, and body weight. It was also higher among males.¹³ Similarly, in our study, the mean vessel diameters were significantly greater in men, and the vessel diameters increased with increased body weight and larger proximal and distal wrist diameters. Multivariate linear regression analyses did not reveal any significant effect of these variables on the ability to estimate radial artery dimensions. It is possible that studies conducted with larger series of patients might be necessary to predict changes in vessel diameters using multivariate analysis.

This is the first study to assess radial artery diameter in the Turkish population, and conventional angiography revealed diameters of 2.3 ± 0.38 mm for men, 2.1 ± 0.42 mm for women, and 2.3 ± 0.40 mm overall. The mean radial artery diameter was reported to be 2.60 ± 0.41 mm by two-dimensional ultrasound in a South Korean population²² and 2.37 ± 0.57 mm by ultrasonography in a Chinese population.²³ Racial variations should be expected, so the differences in the findings of our population were not unexpected. However, the fact that different measurement techniques were used in the studies should also be kept in mind. Radial artery diameter is important when choosing appropriate radial sheaths and instruments. In our study, 74% of the patients had radial artery diameters of 6 Fr or larger. Newly developed instruments are compatible with 6 Fr, and most coronary procedures can be performed via the radial route. In 4 patients, a single Tig II catheter was used for both coronary imagings. Reportedly, transradial intervention is cheaper than the transfemoral approach in terms of the number of catheters used and hospital expenditures.^6-9,24

Besides cardiologists, trainees and residents also perform transradial procedures, and their procedural success rate was 95.8%, which is similar to previously reported findings. The learning period in transradial procedures is fairly long, and the success of the procedure increases with the experience of the operator.^17,25,26 The high procedural success rate, even in the training period, suggests that success rates continue to increase as experience with these procedures is gained.

In the present study, the postprocedural pain level during sheath removal, which is associated with radial artery spasms and procedural complications, did not correlate with BMI, body weight, height, or wrist diameter. In the study by Laurent et al, in which the effect of hypertension on radial artery diameter and function was investigated, radial artery diameter, distensibility, and compliance were found to be similar in both hypertensive and normotensive patients.²⁷ In our study, we found no association between hypertension and pain or discomfort at sheath removal. Similarly, there were no correlations between smoking status and radial artery diameter and pain experienced at sheath removal. In a study performed by Dery et al, which tested the use of a hydrophilic-coated sheath to reduce the traction force needed at withdrawal and the pain experienced by patients afterward, 90 patients were randomly placed into two separate groups to undergo the transradial procedure with the use of either a hydrophilic-coated sheath or a sheath without this coating.²⁹ The peak traction force was recorded at the time of sheath removal, and the patients were asked to quantify their pain. In the group with the hydrophilic-coated sheaths, a reduction of 69% was observed in the traction force needed for sheath removal, and the pain experienced by these patients diminished by 88%. Therefore, the authors recommended the use of hydrophilic-coated sheaths. In the present study, the pain experienced was evaluated subjectively, and 11.8% of our patients expressed discomfort or pain when the sheath was removed. The use of hydrophilic-coated sheaths might have reduced this pain.

Study limitations. One limitation of our study was the low number of patients included. This might have caused problems when demonstrating associations between radial artery diameter, pain experienced by the patients at sheath removal, and the tested parameters. Therefore, further studies with larger populations should be conducted to verify our findings.

Conclusion

In this cross-sectional study, the angiographically-determined mean radial artery diameter was 2.3 ± 0.40 mm, and a positive correlation occurred with regard to body weight and distal and proximal wrist diameter. In multivariate linear regression analyses, none of the variables that were thought to be possible predictors of vessel diameter changes were found to significantly affect radial artery diameter. In fact, we did not find any independent predictors. Coronary procedures performed via the transradial route were successful. Among our patients, 74% had 6 Fr or larger coronary artery diameters. We propose that as long as the ulnar collateral circulation is sufficient, the transradial procedure can be safely performed without considering any other anthropometric parameters.

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From the ¹Gazi University Faculty of Medicine Cardiology Department, Ankara, Turkey ²Numune Hospital, Cardiology Department, Sivas, Turkey, and ³Bayındır Hospital, Cardiology Department, Istanbul, Turkey.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.

Manuscript submitted January 10, 2013, provisional acceptance given March 5, 2013, final version accepted April 1, 2013.

Address for correspondence: Gülten Taçoy, MD, Gazi University Faculty of Medicine, Cardiology Department, Besevler Ankara Turkiye. Email: gtacoy@gmail.com