1) The document discusses the learning curve for radial artery procedures in the US based on multiple data sources. 2) Recent data shows the radial learning curve may not be as steep as once believed, with initial competence reached after 25-40 cases, though improvement continues with greater experience and volume. 3) Procedural metrics like fluoroscopy time improve with experience but are influenced by many factors, making direct links to patient outcomes difficult to establish. Nonetheless, radial procedures in the US are being adopted quickly and appear to achieve better safety outcomes than femoral procedures.

1. Impact of Learning Curves on Clinical
Outcomes in the US
Robert J Applegate, M.D.
Professor of Internal Medicine-Cardiology

2. Disclosures
Advisory Board Abbott Vascular
Research Grants Abbott Vascular
St Jude Medical
Consultant
Abbott Vascular
Serruys, PW. PCR 2010
Wake Forest School of Medicine
AIM Radial 2013

3. The learning curve for radial artery procedures:
historical perspective
No differences in primary entry site complications, or
MACE, but “there was a clear trend toward more
technical difficulties and more problems with the radial
approach.”
Wake Forest School of Medicine
AIM Radial 2013

4. The learning curve for radial artery procedures:
historical perspective
“In conclusion, it is evident, when reviewing
this study, that the difficulties associated with
the learning curve must be overcome
before a randomized study can be carried
out.”
Wake Forest School of Medicine
AIM Radial 2013

5. Radial “learning curve” identified early on with
attempts to quantify the “steepness” of the curve
Inflection ??
Plateau ??
Wake Forest School of Medicine
Spaulding et al: CCI 1996; 39:365-370
AIM Radial 2013

6. The word in the US Interventional World
The first person to describe the learning curve was Hermann Ebbinghaus in 1885, in the
field of the psychology of learning
is that the radial learning curve is “steep”
But is that really true?
Radial ??
Radial ??
Radial ??
Wake Forest School of Medicine
AIM Radial 2013

7. The learning curve for radial artery procedures:
Quantifying the curve and
Linking the learning curve to outcomes
•
Complex interaction of factors that influence the learning curve:
Operator and center experience and volume; presence of fellows
Cath lab tolerance for ramp up, longer cases if needed
Case mix including STEMI, graft cases
•
Metrics to define the curve include both procedural process metrics
(eg floro time) as well as traditional patient outcomes(eg access
complication rates); not uniformly accepted standards
• Data establishing causality between individual learning curve
procedural process metric and patient outcome metric are lacking
Wake Forest School of Medicine
AIM Radial 2013

8. Recent worldwide data on
The learning curve for radial artery procedures:
RIVAL Trial data
Wake Forest School of Medicine
Jolly et al; JACC CI 2013; 6:258-66
AIM Radial 2013

9. Recent worldwide data on
The learning curve for radial artery procedures:
RIVAL Trial data
Center center
Operator air kerma
Operator andVolume volumes associated with lowerVolume
Interaction between operator and center volumes remains to be
fully elucidated
Wake Forest School of Medicine
Jolly et al; JACC CI 2013; 6:258-66
AIM Radial 2013

10. Recent worldwide data on
The learning curve for radial artery procedures:
Registry data
(Dedicated radialist)
(Standard radialist)
Case volume affects failure rate
Both low and high volume operators
continue to improve over time
Both p<0.05 vs
2005-2006
Wake Forest School of Medicine
Burzotta et al AHJ 2012; 163:230-238
AIM Radial 2013

11. The US experience of radial artery procedures:
NCDR CATH/PCI Registry data
Wake Forest School of Medicine
Feldman et al; Circ 2013; 127:2295-2306
AIM Radial 2013

12. The US experience of radial artery procedures:
NCDR CATH/PCI Registry data
16.1% 3rd Q 2012
Wake Forest School of Medicine
Feldman et al; Circ 2013; 127:2295-2306
AIM Radial 2013

13. The US learning curve for radial artery procedures:
Wake Forest Registry data
Wake Forest School of Medicine
Turner et al; CCI 2012; 80:247-257
AIM Radial 2013

14. The US learning curve for radial artery procedures:
Wake Forest Registry data
Wake Forest School of Medicine
Turner et al; CCI 2012; 80:247-257
AIM Radial 2013

15. The US learning curve for radial artery procedures:
Wake Forest Registry data
Transition to preferred radial approach resulted in
better patient centered outcomes including lower
access site and bleeding complications
Wake Forest School of Medicine
Turner et al; CCI 2012; 80:247-257
AIM Radial 2013

16. The US learning curve for radial artery procedures:
Wake Forest Registry data
Radial artery access metrics by period
Metric
Transition
Radial
(N = 610)
Preferred TR
Radial
(N = 897)
7 (5-10)
26 (20-36)
66 (51-85)
50 (38-71)
6 (4-9) *
24 (19-34) *
64 (53-83)
49 (40-52)
7 (5-12)
21 (16-30)
16 (10-24)
7 (5-11) *
21 (15-27)
14 (10-19)
76 (56-98)
190 (147-250)
132 (86-191)
74 (55-99)
194 (142-246)
111 (92-122)
Generalized decrease in procedural metrics with
Access site crossover, n (%)
80 (8.9%)
reduced inter quartile ranges 57 (9.3%)
Sheath size, Fr
CATH only
5.0 (0.2)
5.0 (0.1)
Efforts to quantify learning curve(0.4)
PCI
6.0 complicated by *
5.7 (0.5)
Procedure time intervals, minutes
affectinsertion
Sheath of new fellows on monthly basis
5 (3-10)
5 (3-9) *
Intubate coronaries
Total procedure, CATH only
Total procedure, CATH + PCI
Total procedure, PCI only
Fluoroscopy time, minutes
CATH only
CATH + PCI
PCI only
Contrast volume used, mL
CATH only
CATH + PCI
PCI only
Wake Forest School of Medicine
Turner et al; CCI 2012; 80:247-257
AIM Radial 2013

17. The US learning curve for radial artery procedures:
Wake Forest Registry data
Radial artery access metrics by period for operators with highest and lowest proportion of radial artery access
Attending A (HIGH)
Attending B (LOW)
Transition
Preferred TR
Transition
Preferred TR
Metric
(N = 350)
(N = 329)
(N = 272)
(N = 277)
Radial artery access, n / total volume (%)
Access site crossover, n / TR volume (%)
TR procedure time intervals, minutes
Sheath insertion
Intubate coronaries
Total procedure, CATH only
Total procedure, CATH + PCI
Total procedure, PCI only
TR fluoroscopy time, minutes
CATH only
CATH + PCI
PCI only
TR contrast volume used, mL
CATH only
CATH + PCI
PCI only
202/350 (58%)
12/202 (6%)
233/329 (71%) †
12/233 (5%)
93/272 (34%) ‡
15/93 (16%) ‡
171/277 (62%) †‡
18/171 (11%) ‡
6 (4-11)
6 (4-8)
24 (17-33)
61 (47-74)
50 (43-62)
6 (3-10)
5 (4-7) †
20 (16-28) †
53 (41-66) †
51 (28-52)
6 (4-8)
8 (5-13) ‡
29 (21-37) ‡
72 (52-95)
39 (36-41)
5 (3-9) ‡
6 (5-9) †‡
25 (21-35) ‡
68 (59-89) ‡
40 (40-40)
Similar to Burzotta found a volume – outcome
relationship among both higher and lower
5 (4-8)
5 (3-7) †
9 (6-15) ‡
8 (6-13) ‡
18 (12-26)
15 (11-19)
26 (20-39) ‡
22 (16-29) ‡
volume operators†
14 (10-23)
16 (10-19)
23 (21-24)
12 (12-12)
61 (50-83)
141 (106-176)
95 (74-177)
65 (43-83)
141 (119-180)
105 (30-122)
76 (50-98) ‡
191 (153-253) ‡
150 (109-190)
74 (60-91) ‡
197 (149-231) ‡
92 (92-92)
† p<0.05 vs Transition, ‡ p<0.05 vs Attending A. CATH indicates diagnostic catheterization; PCI, percutaneous coronary intervention.
Wake Forest School of Medicine
Unpublished observations
AIM Radial 2013

18. The US learning curve for radial artery procedures:
Vanderbilt Registry data
Wake Forest School of Medicine
Kasasbeh et al; JIC 2012; 24:599-604
AIM Radial 2013

19. The US learning curve for radial artery procedures:
Vanderbilt Registry data
60% radial
Wake Forest School of Medicine
Kasasbeh et al; JIC 2012; 24:599-604
AIM Radial 2013

20. Floro time (min)
The US learning curve for radial artery procedures:
Vanderbilt Registry data
Procedure time (min)
Room time (min)
Incorporation of radial access to our cardiac
catheterization laboratory led to a decrease in
fluoroscopy time in each operator, operator
group, and institute-wide over the last 3 years.
This improvement was seen after
approximately 25 cases and further improved
after 75 cases.
Wake Forest School of Medicine
Kasasbeh et al; JIC 2012; 24:599-604
AIM Radial 2013

21. The US learning curve for radial artery procedures:
NCDR
Wake Forest School of Medicine
Hess et al; ACC 2013
AIM Radial 2013

22. The US learning curve for radial artery procedures:
NCDR
Wake Forest School of Medicine
Hess et al; ACC 2013
AIM Radial 2013

23. The US learning curve for radial artery procedures:
NCDR
More complex cases performed by
higher volume operators
Wake Forest School of Medicine
Hess et al; ACC 2013
AIM Radial 2013

24. The US learning curve for radial artery procedures:
NCDR
Procedural metrics reduced by
higher volume operators
Wake Forest School of Medicine
Hess et al; ACC 2013
AIM Radial 2013

25. The US learning curve for radial artery procedures:
NCDR
Wake Forest School of Medicine
Hess et al; ACC 2013
AIM Radial 2013

26. The US learning curve for radial artery procedures:
NCDR
Wake Forest School of Medicine
Hess et al; ACC 2013
AIM Radial 2013

27. Impact of Learning Curves on Clinical
Outcomes in the US- Summary
• Recent data indicate that the radial learning curve may not be as
“steep” as once believed
• Threshold for initial “competence” 25-40 cases
•
•
Improvement continues with greater experience consistent with
a volume-outcomes interaction
Learning curve may be influenced by practice setting, eg academic
vs non-academic
• Procedural metrics are easily measured but are influenced by
multiple factors making interpretation challenging, and linkage
to outcomes difficult.
• Nonetheless, these data suggest that radial adoption is occurring
quickly and efficiently while achieving a better safety profile
than femoral artery procedures
Wake Forest School of Medicine
AIM Radial 2013