Long-Term Prognosis After Elective Abdominal Aortic Aneurysm Repair Is Poor in Women and Men

The Challenges Remain

Ruth M. A. Bulder, Bsc; Mareia Talvitie, MD; Esther Bastiaannet, PhD; Jaap F. Hamming, MD, PhD; Rebecka Hultgren, MD, PhD; Jan H. N. Lindeman, MD, PhD

Disclosures

Annals of Surgery. 2020;272(5):773-778. 

In This Article

Results

Changes in AAA Management

Time-related changes in AAA and cardiovascular risk management are illustrated in Figure 1. From 2001 until 2015, the proportion of AAA patients treated with EVAR steadily increased from 15.6% to 64.7%. In parallel, the use of statins increased from 20.3% in period 1 to 35.8% period 3 (P < 0.001).[21,22]

Figure 1.

Developments in AAA management between 2001 and 2015. Percentage of EVAR procedures for patients with AAA repair and statin use for the general Swedish population. Percentage of open repair = 100% - percentage of EVAR. AAA indicates abdominal aortic aneurysm; EVAR, endovascular

Three periods were defined based on proportions of treatments with OR versus EVAR. Period 1, with a dominance of open repair (2001–2004); period 2, which reflects a transition period from open repair to EVAR (2005–2011); and period 3, with an EVAR-first strategy (2012–2015) (Figure 1).

Patient Characteristics

A detailed overview of patient characteristics is shown in Table 1. In total, 12,907 (10,683 men (82.7%) and 2224 women (17.3%) underwent elective repair (OR period: n = 2483; transition period: n = 6230; EVAR period: n = 4194). The mean age at repair of patients increased from period 1 to period 3 (71.9 years to 72.8 years, P < 0.001). Apart from a decrease in peripheral artery disease and stroke, the percentage of reported comorbidities increased over time (P < 0.001).

Procedural Mortality (Short-term Survival)

Between period 1 to period 3 the overall procedural (90-day) mortality declined from 4.1% to 1.2% for OR, and from 1.9% to 0.9% for EVAR. The reduction was significant in men (P = 0.001), but not for women (P = 0.104) (Table 2).

Relative Survival (Long-term Survival)

Long-term survival of AAA patients was compared to the survival for the age- and sex-matched general population (relative survival). This analysis showed a stable, persistently impaired relative survival for electively treated AAA patients for all 3 periods (Figure 2). The 4 years relative survival was 0.87 (95% CI: 0.85–0.89), 0.87 (95% CI: 0.86–0.88), and 0.89 (95% CI: 0.86–0.91), for period 1, 2, and 3 respectively (n = 7845 patients). Ten-year survival could only be calculated for the first 2 periods because period 3 had a maximum follow-up of 4 years. The 10-year survival was 0.66 (95% CI: 0.63–0.70) for period 1, and 0.65 (95% CI: 0.62–0.69) for period 2 (n = 1778 patients).

Figure 2.

Relative survival for males and females for respectively period 1, period 2, and period 3 at 1 yr, 4 yr, and 10 yr. Relative survival = observed survival (in study population): expected survival (for matched general Swedish population). 10-yr survival data not available for period 3.

Cause of Death

The cause of death distribution remained unchanged over the 3 periods (Figure 3). Cardiovascular mortality remained the main cause of death, accounting for 51.0%, 47.2%, 47.9% of the long-term mortality in respectively period 1, 2, and 3 (P = 0.429). Neoplasm-related death was the second most common cause of death and was responsible for 23.5%, 25.2%, 21.7% of all long-term deaths (P = 0.412).

Figure 3.

Long-term causes of death (proportions), including all patients who died after 90 d and within 4 yr after elective infrarenal AAA repair. AAA indicates abdominal aortic aneurysm.

Sex Differences

Female patients displayed a persistently more compromised relative survival (Figure 2). The 4-year relative survival for women was respectively: 0.78 (0.72–0.83), 0.80 (0.77–0.83), and 0.78 (0.68–0.84) (mean, 95% CI), compared to 0.89 (0.87–0.91), 0.89 (0.87–0.90), and 0.91 (0.88–0.94) for males for periods 1, 2, and 3. The increased mortality risk for women was confirmed by Cox regression [HR and 95% CI: 1.12 (1.04–1.20)] (Supplemental Table 2).

Sex-differences in survival persisted over time with a 10-year relative survival for women of 0.53 (0.47–0.60) in period 1 and 0.55 (0.48–0.62) in period 2 [males respectively: 0.70 (0.66–0.73) and 0.68 (0.64–0.72)]. Clear sex-differences were also observed for causes of death with cardiovascular causes more common in women (Figure 3).

Potential Bias Due to Change of Patient Selection Over Time

Although potential interference of population changes in age distribution and life-expectancy are covered by the relative survival analysis, conclusions of this time-resolved analysis are potentially interfered by changes in patient selection with a lower intervention threshold for EVAR and as a consequence, potentially more frail patients being repaired in the later time frames. Indeed, there was a small increase in age at repair [0.8 years for males (P = 0.005) and 1.3 years for females (P = 0.925)] over time, and a small increase in the proportion of male (but not female) octogenarians being treated in period 3 (19.6%) versus period 1 (15.7%) (P = 0.002) (Supplemental Figure 1).

A trend towards a lower intervention threshold for frail patients was not supported by the stable (P = 0.782) proportion of repaired/untreated women (conclusions with regard to men are interfered by the introduction of screening in 2006),[23] and by the declining (males) or stable (females) procedural (90-day) mortality (P = 0.000 and P = 0.104, respectively) (Table 2).

Because more direct measures for frailty were unavailable, a sensitivity analysis was performed to test whether conclusions would be impacted by a possible lower intervention threshold (and thus a higher proportion of frail patients) over time. Boundaries for this analysis were based on the proportion of octogenarians in period 3. Supplemental Table 3 shows that progressive elimination of octogenarians did not influence the study conclusions.

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