***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: INTRODUCTION AND OBJECTIVES The right radial ( RR ) approach has been incorporated into daily clinical practice as a valid alternative to the femoral ( F ) approach . The left radial ( LR ) approach is seldom used and few data are available from r and omized studies comparing this approach with F and RR approaches . METHODS We r and omized 1005 consecutive patients referred to a tertiary-care hospital for cardiac catheterization to different approaches . Procedures were performed by three interventional cardiologists experienced in transradial catheterization . There were no exclusion criteria . The primary end-point was the percentage of procedures completed using the assigned approach . Secondary endpoints were the percentage completed in the absence of contraindications to any approach , the duration of the procedure , and the incidence of vascular complications . RESULTS More procedures were completed with the F approach ( LR , 71 % ; F , 92 % ; RR , 68 % ; P < .001 ) . The success rate in the absence of contraindications to any approach ( n=907 ) was greater with the F approach , with no difference between LR and RR approaches ( LR , 80 % ; F , 96 % ; RR , 82 % ; P < .001 ) . The canalization time was greater with the LR approach ( P < .001 ) , the time required for diagnosis was shorter with the F approach ( P < .001 ) and compression was faster with the radial approach ( P < .001 ) . There was no difference in the total duration of diagnostic procedures ( P=.22 ) or interventions ( P=.9 ) . The incidence of vascular complications was lower with the radial approach ( P=.03 ) . CONCLUSIONS The left radial approach is as valid an alternative to the femoral approach as the right radial approach BACKGROUND most of the studies assessing transradial approach for coronary angiography ( CA ) have been performed through right radial approach ( RRA ) . Our aim was to evaluate the safety and efficacy of left radial approach ( LRA ) compared with RRA for coronary procedures . METHODS from January 2009 to December 2009 , in 2 hospitals , 1,540 patients were r and omized to RRA ( 770 patients ) or LRA ( 770 patients ) for percutaneous coronary procedures . The primary end point was fluoroscopy time for CA and for percutaneous coronary intervention ( PCI ) evaluated independently . Prespecified subgroup analyses according to patient age and operator experience were planned . RESULTS in 1,467 patients ( 732 RRA and 735 LRA ) , a CA ( diagnostic group ) was performed , and in 688 ( 344 each for RRA and LRA ) , a PCI . In the diagnostic group , LRA was associated with significantly lower fluoroscopy time ( 149 seconds , interquartile range [ IQR ] 95 - 270 seconds ) and dose area product fluoroscopy ( 10.7 Gy cm(2 ) , IQR 6 - 20.5 Gy cm(2 ) ) compared with the RRA ( 168 seconds , IQR 110 - 277 seconds , P = .0025 and 12.1 Gy cm(2 ) , IQR 7 - 23.8 Gy cm(2 ) , P = .004 , respectively ) . In the PCI group , there were no significant differences in fluoroscopy time ( 614 seconds , IQR 367 - 1,087 seconds for LRA and 695 seconds , IQR 415 - 1,235 seconds , P = .087 for RRA ) and dose area product fluoroscopy ( 53.7 Gy cm(2 ) , IQR 29 - 101 Gy cm(2 ) for LRA and 63.1 Gy cm(2 ) , IQR 31 - 119 Gy cm(2 ) , P = .17 for RRA ) . According to subgroup analyses , the differences between LRA and RRA were confined to older patients ( ≥ 70 years old ) and to operators in training . CONCLUSIONS left radial approach for coronary diagnostic procedures is associated with lower fluoroscopy time and radiation dose adsorbed by patients compared with the RRA , particularly in older patients and for operators in training There are anatomical differences between right and left radial artery approaches for coronary catheterization that could influence application of the technique . We present the results of a r and omized study that compared the effectiveness of the two approaches and identified factors associated with failure of the procedure . The study involved 351 consecutive patients : a  left radial approach was used in 180 , and a right radial approach , in 171 . The procedure could not be completed using the initial approach selected in 15 patients ( 11 right radial vs. 4 left radial ; P=.007 ) . Use of a right radial approach , lack of catheterization experience , patient age > 70 years , and the absence of hypertension were found to be independently associated with prolonged fluoroscopy duration and failure using the initial approach . Use of the right radial approach in patients aged over 70 years was associated with a 6-fold increase in the risk of an adverse event . Consequently , use of the right radial approach should be avoided in patients aged over 70 years when trainee practitioners are on the learning curve Objective Trans-radial and trans-ulnar access is increasingly used for percutaneous coronary procedures , but spasm or pain may limit comfort and compliance . Intra-arterial lidocaine administration could provide a local anaesthetic eff ect , but its risk-benefi t ratio is unclear . We aim ed to compare intraarterial lidocaine versus saline to reduce peri-procedural discomfort during percutaneous trans-radial or trans-ulnar procedures . Methods and results Patients undergoing percutaneous trans-radial or trans-ulnar coronary procedures were single-blinded r and omly assigned to intra-arterial treatment with 20 mg lidocaine or saline . The primary end-point of the study was local pain , measured on a 10-point scale . A total of 101 patients were enrolled ( 50 allocated to lidocaine and 51 to saline ) . Trans-radial access was employed in 48 ( 96 % ) and 47 ( 92 % ) , respectively , trans-ulnar access in 2 ( 4 % ) and 4 ( 8 % ) , and coronary intervention was performed in 18 ( 36 % ) and 11 ( 22 % ) . Severity of local pain was equivalent in both groups ( 2.3 ± 2.3 vs. 3.0 ± 2.5 , P = 0.167 ) . Similar results for both groups were found also for local spasm , local access success , procedural success , and net clinical adverse events ( all P > 0.05 ) . No sustained cardiac arrhythmia or neurologic symptom developed in any patient . Conclusions Current approaches and techniques for percutaneous trans-radial or trans-ulnar coronary procedures are associated with few local or systemic complications . Local forearm/wrist pain is relatively frequent in this setting , and is not signifi cantly prevented by intra-arterial lidocaine OBJECTIVES This study sought to compare procedural and clinical outcomes of percutaneous transluminal coronary angioplasty ( PTCA )  performed with 6F guiding catheters introduced through the radial , brachial or femoral arteries . BACKGROUND Transradial PTCA has been demonstrated to be an effective and safe alternative to transfemoral PTCA ; however , no r and omized data are currently available . METHODS A r and omized comparison between transradial , transbrachial and transfemoral PTCA with 6F guiding catheters was performed in 900 patients . Primary end points were entry site and angioplasty related . Secondary end points were quantitative coronary analysis after PTCA , procedural and fluoroscopy times , consumption of angioplasty equipment and length of hospital stay . RESULTS Successful coronary cannulation was achieved in 279 ( 93.0 % ) , 287 ( 95.7 % ) and 299 ( 99.7 % ) patients r and omized to undergo PTCA by the radial , brachial and femoral approaches , respectively . PTCA success was achieved in 91.7 % , 90.7 % and 90.7 % ( p = NS ) of patients , with 88.0 % , 87.7 % and 90.0 % event free at 1-month follow-up , respectively ( p = NS ) . Major entry site complications were encountered in seven patients ( 2.3 % ) in the transbrachial group , six ( 2.0 % ) in the transfemoral group and none in the transradial group ( p = 0.035 ) . Transradial PTCA led to asymptomatic loss of radial pulsations in nine patients ( 3 % ) . Procedural and fluoroscopy times were similar , as were consumption of guiding and balloon catheters and length of hospital stay ( [ mean + /- SD ] 1.5 + /- 2.5 , 1.8 + /- 3.8 and 1.8 + /- 4.2 days , respectively ) . CONCLUSIONS With experience , procedural and clinical outcomes of PTCA were similar for the three subgroups , but access failure is more common during transradial PTCA . Major access site complications were more frequently encountered after transbrachial and transfemoral PTCA In a previous study , the radial approach for coronary angiography was shown to be associated with a lower success rate and longer procedural and X‐ray times compared to the femoral approach . However , this approach is associated with a steep learning curve . A series of 210 consecutive nonselected patients were r and omized to  femoral versus right radial approach or femoral versus left radial approach  by two experienced operators . Clinical characteristics were similar in the three groups . Technical failure occurred in one patient in the right radial group with subsequent crossover to left radial artery . The number of coronary catheters used was lower in the right radial group ( 1.4 ± 0.7 vs. 2.1 ± 0.4 for the two other groups ) . The procedural duration was longer with left radial ( 14.2 ± 3.3 min ; P < 0.05 ) approach than with right radial ( 12.4 ± 5.8 min ) and femoral ( 11.2 ± 3.3 min ) without significant differences between femoral and right radial . X‐ray exposure was shorter in the femoral group ( 3.1 ± 1.7 min ) than in both radial groups ( right : 3.8 ± 2.2 min ; left : 4.2 ± 1.7 min ) . The angiographic quality was not different between the three groups for RCA , but was less good for LCA through right radial approach . Bed rest and hospital stay were shorter in the two radial groups . The comfort was judged better with the transradial approach . An ad hoc PTCA was performed in 45.7 % of femoral patients , 41.4 % of right radial , and 44.3 % of left radial with immediate sheath withdrawal ( closure device for femoral group ) . There were no severe complications in the three groups , but two patients from the femoral group were discharged later because of vascular complications . The total cost of coronary angiography was higher in the femoral group . In conclusion , after the learning period , transradial coronary angiography can be performed with a high success rate , low rate of complication , and good angiographic quality . It is associated with a slight increase in procedural ( LR ) and fluoroscopy times , but permits earlier ambulation and discharge , improves patient comfort , and reduces the cost . Cathet Cardiovasc Intervent 2001;52:181–187 . © 2001 Wiley‐Liss , The transradial approach for catheterization is becoming increasingly more popular . At present , the choice of the right or left radial artery depends on the operator 's preference . We examined how the laterality influenced the effectiveness of the approach . Employing Judkins‐type catheters , we performed coronary angiography  in 232 patients with the left approach and in 205 patients with the right approach .  Although access time did not differ between the two groups of patients , the duration of catheter manipulation was shorter in the left‐ than in the right‐approach group ( 11.7 ± 5.9 vs. 9.8 ± 4.4 min ; P < 0.001 ) . Because of the shorter duration of catheter manipulation , the total procedural duration was shorter in the left‐approach group ( 13.7 ± 6.4 vs. 11.4 ± 4.8 min ; P < 0.001 ) . The fluoroscopy time was shorter in the left‐ than in the right‐approach group ( 3.7 ± 2.5 vs. 5.0 ± 3.3 min ; P < 0.001 ) . The amount of contrast material did not differ between the groups ( 79 ± 27 vs. 83 ± 25 ml ) . The rate of guidewire usage to engage the coronary ostium was higher in the right‐ than in the left‐approach group because of the severe tortuosity of the right subclavian artery ( 20/205 vs. 0/232 ; P < 0.001 ) . Thus , for operators with significant experience , the left radial approach may provide increased procedural efficacy for coronary angiography compared to the right radial approach . Catheter Cardiovasc Interv 2004;61:333–337 . © 2004 Wiley‐Liss , Objectives : To compare in terms of efficacy and safety the transulnar to the transradial approach for  coronary angiography and angioplasty . Background : Opposite to the transradial approach , which is now widely used in catheterization laboratories worldwide , the ulnar artery approach is rarely used for cardiac catheterization . Methods : Diagnostic coronarography , followed or not by angioplasty , was performed 
    Output:
    
Right and left radial accesses appear largely similar in their overall procedural and clinical performance during transradial diagnostic or interventional procedures .