1 Timeline of data
2 Timeline from diagosis to treatment

1 Timeline of data

The first fEVAR was performed on 17 December 2009
Since then 84 have been performed up until 24 April 2023
However, the fEVAR performed before 10 March 2015 were offered ad hoc and some fEVAR have been performed on an ‘urgent scheduled’ basis meaning pre-operative investigations will have been fast-tracked.
The remaining 71 are counted as part of the formal elective fEVAR ‘service’.

2 Timeline from diagosis to treatment

The following applies to primary fEVAR only
Fenestrated cuffs have been omitted intentionally (n = 3)
Non-elective cases have also been intentionally ommitted

2.1 Time to CT

Time to CT is defined as the time between imaging showing the aneurysm to have reached treatment threshold until the planning CT angiogram.
In 11 cases, a CT suitable for planning was also the investigation which showed the aneurysm to be at threshold and so time to CT was 0 days.
These cases are therefore excluded from the following.
Time to CT is shown on the following histogram:

These look abnormally distributed.
Comparison of time to CT between screened and non-screened patients can be visualised as a boxplot, given that boxplots display the median and IQR which are the appropriate measures for these data:

These look different and this can be tested with a Mann Whitney U test to compare the groups with the alternative hypothesis that screened patients wait less time to have CTA.
p = 0.02 - the alternative hypothesis can be accepted for screened vs non-screened men.

2.2 Time to ECHO

7 patients did not have a documented echocardiogram.
7 patients had ECHO prior to their imaging reaching treatment threshold size and did not have it repeated prior to fEVAR.
That leaves 57 patients who had ECHO after reaching treatments threshold.
The distribution of time to ECHO is shown in the following histogram:

These look abnormally distributed.
Comparison of time to ECHO between screened and non-screened patients can be visualised as a boxplot, given that boxplots display the median and IQR which are the appropriate measures for these data:

These look similar and this can be tested with a Mann Whitney U test to compare the groups with the alternative hypothesis that screened patients wait less time to have ECHO.
p = 0.01 - the alternative hypothesis can be accepted for screened versus non-screend men.

2.3 Time to PFT

13 patients did not have documented pulmonary function tests.
6 patients had PFTs prior to their imaging reaching treatment threshold size and did not have it repeated prior to fEVAR.
That leaves 52 patients who had PFT after reaching treatments threshold.
The distribution of time to PFT is shown in the following histogram:

These look abnormally distributed.
Comparison of time to PFT between screened and non-screened patients can be visualised as a boxplot, given that boxplots display the median and IQR which are the appropriate measures for these data:

These look similar and this can be tested with a Mann Whitney U test to compare the groups with the alternative hypothesis that screened patients wait less time to have PFT.
For comparisons between the three groups, p = 0.08, 0.51, 0.72 - the null hypothesis that there is no difference in time to PFT cannot be rejected.

2.4 Time to MDT

7 patients did not have documented MDT discussion.
2 patients had MDT discussion prior to their imaging reaching treatment threshold size and did not have it repeated prior to fEVAR.
That leaves 62 patients who had MDT after reaching treatments threshold.
The distribution of time to MDT is shown in the following histogram:

These look abnormally distributed.
Comparison of time to MDT between screened and non-screened patients can be visualised as a boxplot, given that boxplots display the median and IQR which are the appropriate measures for these data:

These look similar and this can be tested with a Mann Whitney U test to compare the groups with the alternative hypothesis that screened patients wait less time to have MDT.
p = 0.02 - the null hypothesis that there is no difference in time to MDT can be rejected for screened versus non-screened men.

2.5 Time to fEVAR

The distribution of time to fEVAR is shown in the following histogram:

These look abnormally distributed.
Median and IQR for time to fEVAR are shown below:

Characteristic	Value (days)
Median time	204
Interquartile range	146 - 277.5

Comparison of time to fEVAR between screened and non-screened patients can be visualised as a boxplot, given that boxplots display the median and IQR which are the appropriate measures for these data:

These look similar and this can be tested with a Mann Whitney U test to compare the groups with the alternative hypothesis that screened patients wait less time to have fEVAR.
For comparisons between the three groups, p = 0.21, 0.69, 0.69 - the null hypothesis that there is no difference in time to fEVAR cannot be rejected.

2.6 Comparative timeline

The different time delays presented above can be shown together in a single boxplot:

It is visually apparent that CT imaging, ECHO, PFTs and MDT discussion are parallel investigations with none incurring a particular time penalty.
There is a subsequent delay to the procedure, some of which can be accounted for by the time taken to manufacture a custom stent-graft.