1 Notes

2 Timeline of fEVAR in GG&C

2.1 fEVAR and EVAR numbers over time

  • The number of infra-renal elective EVAR and all fEVAR per year since the first fEVAR was performed are shown below:

2.2 fEVAR numbers over time

  • The number of fEVAR per year since the first fEVAR was performed are shown below:

2.3 fEVAR device over time

  • Choice of stent-graft has changed over time, as shown below:

  • Total numbers of each stent-graft used are shown here:

3 Sex, age and healthboard of patients undergoing fEVAR in GG&C

3.1 Sex

  • Split between men and women, the numbers of fEVAR are as follows:
Characteristic N = 1111
Sex
    Man 92 (83%)
    Woman 19 (17%)
1 n (%)
  • Further breaking down the men into those whose aneurysm was discovered by the national aneurysm screening programme:
Characteristic N = 1111
Detection state:
    Non-screened man 68 (61%)
    Screened man 24 (22%)
    Woman 19 (17%)
1 n (%)
  • Since 2012, men in Scotland have been invited to attend in the year of their 65th birthday for an ultrasound to detect AAA.
  • If the aneurysm was detected by the screening programme, both those who had an aneurysm of treatment size at first screen and those who had an aneurysm below treatment size which subsequently grew to treatment size are included in the ‘screened’ category.

3.2 Age

  • Patient ages varies from 60 to 86 years old with the distribution shown on the following histogram:

  • These data look normally distributed but this can be tested by Shapiro Wilk normality test with the null hypothesis that the age data are normally distributed: p = 0.27.
  • Data are therefore best summarised with mean and standard deviation:
Characteristic N = 1111
Age 73.6 (5.4)
1 Mean (SD)
  • To assess for any difference between men and women, first we should check the age for both groups is evenly distributed:

  • As these are both evenly distributed they can be compared with a t test:
Characteristic Man, N = 921 Woman, N = 191 p-value2
Age 73.6 (5.6) 73.5 (4.6) 0.9
1 Mean (SD)
2 Welch Two Sample t-test
  • There is no statistical difference.
  • Finally, we can assess for any difference between screened men, non-screened men and women, first checking the age for both groups is evenly distributed:

  • Screened men clearly have an abnormally distributed age and so ages should be compared with a Kruskall-Wallis test:
Characteristic Non-screened man, N = 681 Screened man, N = 241 Woman, N = 191 p-value2
Age 75.0 (72.0, 79.0) 70.0 (68.0, 73.0) 74.0 (71.0, 76.5) <0.001
1 Median (IQR)
2 Kruskal-Wallis rank sum test
  • There is a statistical difference between the ages.

3.3 Health Board

  • Not all fEVAR are for Greater Glasgow & Clyde health board patients.
  • Since 2019, Greater Glasgow & Clyde health board has taken over the vascular services of Forth Valley health board.
  • The patient’s health board are shown on the following column chart:

3.4 Size

  • Treated aneurysm size varies from 40 mm (in a patient with a common iliac artery at treatment threshold and AAA below treatment threshold) to 100 mm, as shown on the following histogram:

  • Shapiro Wilk normality test with the null hypothesis that the age data are normally distributed: p = 0 (ie. they are abnormally distributed)
  • Data are therefore best summarised with median and interquartile range:
Characteristic N = 1111
AAA size (mm) 59 (57, 63)
1 Median (IQR)
  • As we have previously seen that screened men are treated younger than non-screened men, we can quickly assess if the same holds true for the size of their (and women’s) aneurysms:
Characteristic Non-screened man, N = 681 Screened man, N = 241 Woman, N = 191 p-value2
AAA size (mm) 60 (57, 65) 59 (58, 61) 60 (58, 62) 0.7
1 Median (IQR)
2 Kruskal-Wallis rank sum test
  • There is no significant difference in aneurysm size.