Trends in the utilization of endovascular therapy for elective and ruptured infrarenal and thoracic aortic aneurysm procedures across Canada

P. Jetty*, D. Husereau**, T. Brandys*, G. Hajjar*, A.Hill*, S. Nagpal*

Prasad Jetty MD*

* Division of Vascular and Endovascular Surgery The Ottawa Hospital and the University of Ottawa, Canada** Canadian Agency for Drugs and Technologies in Health

Introduction• Popularity for EVAR has grown and traditional restrictions to a

high-risk population are no longer apparent leading to rapid and wide-scale implementation

• Enthusiasm for EVAR has been tempered by a better understanding of its long-term durability

• Mid-term results from two randomized controlled trials have demonstrated that the initial operative survival advantage following EVAR was not sustained, with EVAR having a higher associated re-intervention rate and cost.

• Despite these results, EVAR utilization has continued to increase, with rapidly evolving technology and liberalization to younger and lower risk patients

EVAR in Canada

• There is limited data that document trends for EVAR utilization in Canada and internationally as well

• This is the first study to examine utilization rates of open and endovascular repair in Canada, in a universal health –care system that includes all age groups

Objective

• Primary objectiveDetermine the trend of utilization of EVAR for elective, non-ruptured and ruptured AAAs and descending TAAs in Canada

Methodology

Creation of the cohort• Universal health care system for all age groups (single

payer system)

• 2 population-based administrative databases

• The Canadian Institute for Health Information-Discharge Abstract Database (CIHI-DAD); patients from Quebec were recently added

• The Estimates of Population (CANSIM database) produced by Statistics Canada- which provides annual estimates of population by age and sex for Canada, provinces and territories

Inclusion and Exclusion Criteria

• Inclusion • All patients with non-ruptured or ruptured abdominal

aortic aneurysm (AAAs) and isolated descending thoracic aortic aneurysms (TAAs) fixed by either open surgical technique or by EVAR.

• Exclusion• thoracoabdominal aneurysms, isolated iliac aneurysms,

and pseudoaneurysms

Coding Algorithm

• Validated coding algorithm of ICD-10 diagnostic codes and CCI therapeutic codes developed by our team (>95% accuracy)

• Jetty P, van Walraven C. Coding accuracy or abdominal aortic aneurysm repair procedures in administrative databases - a note of caution. J Eval Clin Pract. 2011 Feb;17(1):91-6.

– Patients were classified in the open surgical group if they were coded with a diagnosis of non-ruptured AAA (I71.4) and intervention codes for an open AAA procedure.

– Patients were placed in the EVAR group if they were coded with a diagnosis of non-ruptured AAA and intervention codes for an EVAR.

– A similar grouping for procedures was performed for patients coded for ruptured AAAs (I71.3)

Analysis• Variations in population numbers

• Geographic• Time (by year)

• Standardized for annual population over 65 years of age within each province

• “per capita rate” (per 100000 population over 65).

• Although we only have 5 data points (one for each year of the study period) each point represents hundreds to thousands of observations, therefore comparisons were qualitative vs quantitative

Results

• Between April 2004 and March 2011

• 27, 875 AAA procedures were performed in Canada

• open repair (n=20, 125)• EVAR (n=7,750)

• 1090 TAA procedures were performed in Canada

• open repair (n=546)• TEVAR (n=544)

Distribution of AAA Procedures

Procedures performed in the province of Ontario accounted for 36.6% of all procedures performed in Canada.

Proportion of AAA procedures by province in Canada as of

2011

NF

PEI

NS

NB

QC

ON

MB

SK

AB

BC

Quebec

Ontario

Results - AAAs• Proportion of EVAR increased from 11.5% in 2005 to 40.5% in 2011, with

out affecting the total number of all AAA procedures

Number of AAA procedures in Canada

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

2005 2006 2007 2008 2009 2010 2011

Num

ber o

f pro

cedu

res

EVAR

Open

Results per capita - AAAs

• “Per Capita” rates for EVAR, OSR, and total AAA procedures

AAA procedure rates in Canada (per 100000 population >65 years)

0.0

20.0

40.0

60.0

80.0

100.0

120.0

2005 2006 2007 2008 2009 2010 2011

Num

ber o

f pro

cedu

res

per 1

0000

0 po

pula

tion

> 65

Open

EVAR

Total

Results – Thoracic aneurysms• Similar trend was seen in “Per Capita” rates for TEVAR and total TAA

procedures• OSR rates decreased slightly per capita

TAA procedure rates in Canada (per 100000 population over 65 years of age)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

2005 2006 2007 2008 2009 2010 2011

Num

ber o

f pro

cedu

res

per 1

0000

0 po

pulati

on >

65

Open

EVAR

Total

AAA procedures per capitaNon-Atlantic provinces

• Consistent in non-Atlantic provinces

AAA procedure rates in the non-Atlantic Provinces(per 100000 population >65 years)

50.0

70.0

90.0

110.0

130.0

150.0

170.0

190.0

210.0

2005 2006 2007 2008 2009 2010 2011

Num

ber o

f pro

cedu

res

per 1

0000

0 po

pula

tion

>65

Canada

ON

MB

SK

AB

BC

QC

AAA procedures per capitaAtlantic provinces

• AAA procedure rates per capita were highest in the Atlantic provinces

AAA procedure rates in the Atlantic provinces(per 100000 population >65 years)

50.0

70.0

90.0

110.0

130.0

150.0

170.0

190.0

210.0

2005 2006 2007 2008 2009 2010 2011

Num

ber o

f pro

cedu

res

per 1

0000

0 po

pula

tion

>65

Canada

NF

PE

NS

NB

EVAR per capita by province • Highest in Newfoundland and lowest in Quebec, Manitoba and Saskatchewan

EVAR for non-ruptured AAA (per 100000 population >65 years)

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

2005 2006 2007 2008 2009 2010 2011

Num

ber o

f pro

cedu

res

per 1

0000

0 po

pula

tion

>65

Canada

NF

PE

NS

NB

ON

MB

SK

AB

BC

QC

Results - RAAAs

• Ruptured AAA rate per capita was also highest and increasing in the Atlantic provinces despite doing the most AAA procedures

Ruptured AAAs in the Atlantic Provinces (per 100000 population >65 years)

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

50.0

2005 2006 2007 2008 2009 2010 2011

Num

ber

of R

AA

As

per

1000

00 p

opul

ation

>65 Canada

NF

PE

NS

NB

Ruptured AAAs in Canada• Decreasing trend in RAAAs and procedures for RAAAs with an increase in

proportion treated by EVAR

Ruptured AAAs in Canada (per 100000 population >65 years)

2005 2006 2007 2008 2009 2010 2011

Num

ber o

f pro

cedu

res

per 1

0000

0 po

pula

tion

>65

0.0

5.0

10.0

15.0

20.0

25.0

30.0N

umbe

r of r

uptu

red

AAAs

per 1

0000

0 po

pula

tion

>65

EVAR

Open

RAAA

Results• Ruptured AAAs per capita decreased from 26.5 in 2005 to 19.1 in 2011

without affecting the overall AAA procedure rate.• This trend is consistent amongst all provinces

Non-ruptured AAA procedures and ruptured AAAs in Canada (per 100000 population >65 years)

0.0

20.0

40.0

60.0

80.0

100.0

120.0

2005 2006 2007 2008 2009 2010 2011

Num

ber o

f pro

cedu

res

per 1

0000

0 po

pula

tion

>65

0.0

5.0

10.0

15.0

20.0

25.0

30.0

Num

ber o

f rup

ture

d AA

Aspe

r 100

000

popu

latio

n >6

5

EVAR

Open

RAAA

Results

• Ruptured TAAs per capita decreased from 0.60 in 2005 to 0.36 in 2011

• Inverse correlation with total TAA repairs?

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

2005 2006 2007 2008 2009 2010 2011

Num

ber o

f rup

ture

d AA

Aspe

r 100

000

popu

latio

n >6

5

Num

ber o

f pro

cedu

res

per 1

0000

0 po

pula

tion

>65

Non-ruptured TAA procedures and ruptured TAAs in Canada(per 100000 population >65 years)

EVAR

Open

RAAA

How does Canada compare to the United States?

• More gradual implementation of EVAR in Canada

• Proportion of EVAR use in 2011 in Canada are similar to those from 2003-2004 in the United States* (~40%)

• Per capita EVAR rates in 2011 in Canada are similar to those reported in the US in 2001-2002** (~35 per 100000 population over 65)

*Schwarze ML, Shen Y, Hemmerich J, Dale W. Age-related trends in utilization and outcome of open and endovascular repair for abdominal aortic aneurysm in the United States, 2001-2006 J Vasc Surg. 2009 Oct;50(4):722-729

**Levin DC, Rao VM, Parker L, Frangos AJ, Sunshine JH Endovascular repair vs open surgical repair of abdominal aortic aneurysms: comparative utilization trends from 2001 to 2006. J Am Coll Radiol. 2009 Jul;6(7):506-9

United States

*Schwarze ML, Shen Y, Hemmerich J, Dale W. Age-related trends in utilization and outcome of open and endovascular repair for abdominal aortic aneurysm in the United States, 2001-2006 J Vasc Surg. 2009 Oct;50(4):722-729**Levin DC, Rao VM, Parker L, Frangos AJ, Sunshine JH Endovascular repair vs open surgical repair of abdominal aortic aneurysms: comparative utilization trends from 2001 to 2006. J Am Coll Radiol. 2009 Jul;6(7):506-9

Conclusion

• The utilization of EVAR has increased by 29% (11.5% in 2005 to 40.5% in 2011)

• More rapid and widespread adoption of TEVAR (~63.5% of cases in 2011)

• Open AAA and TAA repair rates have decreased

• Overall total AAA procedure rates appear to be slightly decreasing

• Ruptured AAAs have decreased

• Rapid adoption of TEVAR without any level 1 evidence appears to have impacted significantly the rate of ruptured TAAs

Conclusion

• Discrepancies exist with respect to utilization of EVAR and TEVAR within Canada

• We identified the Atlantic provinces of Canada as hot spots for AAAs and TAAs. Despite having the highest AAA procedure rates in the country, they also suffered from the highest rates of RAAAs per capita suggesting a population with higher than usual susceptibility for developing a AAA

Thank you

Discussion

• Why is EVAR rapidly increasing around the world with RCTs that don’t show any MAJOR advantages?

• Why is TEVAR rapidly increasing around the world without ANY RCTs?

• Higher type 1 leaks vs EVAR, can only follow with CT ionizing radiation

• Why is the incidence of ruptured and non-ruptured AAAs appear to be decreasing worldwide?

Sweden

Germany• Germany ~35-40% rate of EVAR as of 2009

• Endovascular abdominal aneurysm repair: trends in Germany.• Santosa F, Moysidis T, Nowak T, Heilmaier C, Berg C, Luther B, Kröger K.• Source• Department of Vascular Medicine, HELIOS Klinikum Krefeld, Germany.• Abstract• BACKGROUND: • As a minimally invasive technique endovascular aneurysm repair (EVAR) reduces the risk of mortality and should be the preferred technique used in

older patients. We analysed trends in endovascular and open surgical procedures in patients hospitalized for abdominal aortic aneurysm (AAA) in Germany.

• PATIENTS AND METHODS: • We used national statistics (DRG statistics) published by the Federal Office of Statistics in Germany to calculate the incidence of patients hospitalised

with ruptured (rAAA) and elective (eAAA) AAA. In addition, annual procedure rates of endovascular (EVAR) procedures were calculated.• RESULTS: • Incidence rates of eAAA per 100,000 males (females) showed a small increase from 2006 to 2007 but remained almost unchanged with 74.8 (8.8) in

2007 and 74.5 (9.8) in 2009. Incidence rates of rAAA per 100 000 males remained unchanged but showed a decreasing trend in females. The rate of people treated by EVAR increased form 2006 to 2009: in males from 24.0 % to 40.3 % and in females from 17.3 % to 31.0 %. In younger males (55 - 60 years) the increase in those who received EVAR was smaller (from 22.1 % to 33.9 %) than in older males (85 - 90 years) (from 20.4 to 41.6 %). Despite a clear increase in the use of EVAR from 2006 to 2009 there is only a small trend in reduction of the death rates which is more pronounced in rAAA.

• CONCLUSIONS: • There has been a relevant increase in EVAR procedures for the treatment of AAA in Germany in recent years. Parallel to this

increase of EVAR, aneurysm-related in-hospital deaths seem be declining slightly. A causal relationship between these trends remains to be proven.

Discussion

• Despite publications of randomized trials showing no difference in long-term mortality, EVAR utilization has continued to increase in Canada

• The increased use of EVAR in Canada could be due to:

• a perceived limited generalizability of the randomized trials (because of their highly selected patient population)

• a perceived improvement in EVAR technology and expertise since the studies were conducted

Discussion

• Historically, introduction of minimally invasive technology has been accompanied by overall higher surgical volumes due to lower operative thresholds (e.g. laparoscopic cholecystectomy)

• Some centres around the world reported an increase in total number of AAAs treated with introduction of endovascular technology

• However this has not been the experience for EVAR in Canada.

Discussion

• The decline in ruptured AAAs is likely multi-factorial

• National campaigns and increased awareness of the benefits of AAA screening

• Treatment of high-risk patients with EVAR, who would have otherwise been denied an open repair and perhaps gone on to rupture their AAA, played a role in the overall decline of RAAAs

• The existing seniors’ population in Canada may not have the same susceptibility for AAA development, compared to previous senior generations, as the less-susceptible ethnic (non-Caucasian) population of Canada ages.

Limitations• Administrative databases can be susceptible to inaccurate

coding

• We minimized this problem in our analysis by developing and using a coding algorithm that classified patients in the correct surgical treatment group with over 95% accuracy

• Although our study attempted to standardize differences in proportions of elderly populations between provinces, it is quite possible that some populations over 65 are older than others, thus affecting expected per capita rates.

Open Surgical Repair (OSR)

Thoracic Endovascular Aneurysm Reapir (TEVAR)

Results

• Between April 2004 and March 2011

• 1090 TAA procedures were performed in Canada

• open repair (n=546)• EVAR (n=544)

Results• The proportion of all elective TAA repairs by TEVAR increased from 24.5%

in 2005 to 63.6% in 2011• Total number of procedures performed also increased

Number of Elective TEVARs vs OSR of TAAs

0

50

100

150

200

250

2005 2006 2007 2008 2009 2010 2011

Num

ber o

f pro

cedu

res

United States

TAA procedure rates in Canada (per 100000 population >65 years)

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

2005 2006 2007 2008 2009 2010 2011

Num

ber

of p

roce

dure

s pe

r 10

0000

pop

ulati

on >

65

Open

EVAR

Total

Ottawa

Discussion

• Despite no randomized trials, there is wide acceptance of TEVAR in Canada compared to EVAR

• Is there is a perception that results are obviously improved with TEVAR (do we need an RCT to show that TEVAR is better)

• Type 1 endoleaks post-TEVAR are reported higher vs post-EVAR

• TEVAR requires more ionizing radiation surveillance- Surveillance following TEVAR has been suggested to be more important c/w EVAR

• Is it too late to do an RCT?

Discussion

• Why has TEVAR utilization increased

• Lower threshold for providing treatment » Higher risk individuals» Less morbidity (paralysis), mortality even in healthy individuals» Smaller aneurysms?

• Increased use of CT scans has increased the incidental detection rate (no formal screening program in place)

• Wider availability of adequately skilled vascular surgeons in smaller centres who can do TEVAR vs availability of those skilled to do OSR of TAAs which was previously confined to larger centres

Discussion

• The decline in ruptured TAAs is likely multi-factorial

• Increased detection (purposeful or incidental)

• Treatment of high-risk patients with TEVAR, who would have otherwise been denied an open repair and perhaps gone on to rupture their TAAA, likely played a role in the overall decline of RTAAs

• The demographic of the seniors’ population in Canada is changing- perhaps this new demographic (eg. non-caucasians, may not have the same susceptibility for TAA development and rupture, compared to previous senior generations)

Future

• Boundaries between TAA and TAAA are being increasingly blurred with advent of branched and fenestrated EVAR etchnology making any future comparison of open endovascular techniques very difficult

• The role of other specialists involved in treating aortic pathology will become increasingly more apparent (i.e. cardiac surgeons)

Results

• TAA procedure rates per capita in non-Atlantic provinces

TAA procedure rates in the provinces outside of Atlantic Canada compared to the national rates

(per 100000 population over 65 years of age)

0.0

2.0

4.0

6.0

8.0

10.0

12.0

2005 2006 2007 2008 2009 2010 2011

Num

ber o

f pro

cedu

res

per 1

0000

0 po

pula

tion

>65

Canada

ON

MB

SK

AB

BC

QC

Results• Per capita rates for TEVAR increased during the study period with the highest rates

in the province of Alberta as of 2011• Differences in TEVAR utilization did not correlate with co-morbidity rates in the

individual populations

TEVAR for non-ruptured TAA in Western Canada (per 100000 population over 65 years of age)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

2005 2006 2007 2008 2009 2010 2011

Num

ber o

f pro

cedu

res

per 1

0000

0 po

pula

tion

>65

Canada

MB

SK

AB

BC

TEVAR for non-ruptured TAA in Eastern Canada(per 100000 population over 65 years of age)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

2005 2006 2007 2008 2009 2010 2011

Num

ber o

f pro

cedu

res

per 1

0000

0 po

pula

tion

>65

Canada

ON

QC

TEVAR for non-ruptured TAA in Atlantic provinces (per 100000 population over 65 years of age)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

2005 2006 2007 2008 2009 2010 2011

Num

ber o

f pro

cedu

res

per 1

0000

0 po

pula

tion

>65

Canada

NF

PE

NS

NB

Results

• Ruptured TAAs per capita in the Atlantic provinces

Ruptured TAA rates in the Atlantic Provinces per 100000 population over 65 years of age

0.0

0.5

1.0

1.5

2.0

2.5

2005 2006 2007 2008 2009 2010 2011

Num

ber o

f RAA

As

per 1

0000

0 po

pula

tion

>65

Canada

NF

PE

NS

NB