Original Article


IBBJ                                                                                                  

Winter 2015, Vol 1, No 1

 

 

Inpatient Mortality Following Repair of Abdominal Aortic Aneurysm in a Tertiary Hospital in Tehran

 

Shervin Assari1*, Mehrdad Karimi2, Hafez Ghaheri3, Ali Akbar Beigi4, Maryam Moghani lankarani5, Fereshteh Rahimzadeh6

 

1. University of Michigan School of Public Health, Ann Arbor, MI, USA

2. Department of Surgery, Shahrekord University of Medical Sciences, Shahrekord, Iran

3. Department of Surgery, Isfahan University of Medical Sciences, Isfahan, Iran

4. Medicine and Health Promotion Institute, Tehran, Iran

5. Universal Network for Health Information, Dissemination and Exchange (UNHIDE), Tehran, Iran

 

Submitted 17 Sep 2014; Accepted 16 Nov 2014; Published 8 Feb 2015

This study was conducted to monitor the rate of inpatient mortality and its associated factors following open reconstruction of abdominal aortic aneurysm (AAA) in a tertiary hospital in Tehran, Iran. This retrospective study was a chart review of 112 patients undergoing open in­frarenal abdominal aortic aneurysm surgery in one of the main tertiary hospitals in Tehran, Iran. Baseline data (demographic data, risk factors) and outcome data (any cause mortality) were available in 106 cases, which included into this study. The inpatient mortality was very high (23.5%). Regression analysis revealed that in-patient mortality was higher in those with age over 70 years (OR=3.028, 95% CI= 1.099- 8.337) and those who developed temporary worsening of the renal function (OR=3.141, 95% CI= 1.071-9.21). High inpatient mortality rate of the AAA reconstruction in this study is alarming. The decrease in the renal function in the wake of infra-renal aortic surgery and also high age seem to be main risk factors of the increased inpatient mortality.

 

Key Words: Aortic surgery, Mortality, Renal dysfunction

 

 

 

 

 


 

 


*Corresponding author:  Shervin Assari, MD, MPH

  Center for Research on Ethnicity, Culture, and Health (CRECH)
  Department of Health Behavior and Health Education
  University of Michigan School of Public Health

  Email: assari@umich.edu

 

 



A

n abdominal aortic aneurysm (AAA) is a dilated and weakened segment of the ab­dominal aorta that occurs as a consequence of aortic medial degener­ation. Its risk factors include high age, male gen­der, cigarette smoking, hyper­tension and raised cholesterol levels (1-3). Pa­tients with AAA are at risk of vascular rupture, a catastrophic clinical emergency (2, 4). Nowadays, repair of AAA is an increasingly common surgical procedure.

 

Monitoring of inpatient mortality after AAA repair is used for making comparisons be­tween different health care settings, from different hospitals (5, 6) and countries. Such comparisons are believed to provide essential evidences for public health practitioners, policy makers and clinicians about whether outcomes are acceptable in their served population or not (7).

 

Up to our knowledge, there is no pub­lished data regarding the outcome of reconstruc­tion of infra-renal AAA, from Iran. This study, therefore, sought to determine the rate of all-cause inpatient mortality and its associated factors fol­lowing reconstruction of infra-renal AAA in one of the main tertiary hospitals in Tehran, Iran.

 

    Materials & Methods                                     


This is a secondary analysis of a retro­spective chart review of all 112 consecutive pa­tients who underwent reconstruction of AAA re­quiring infra-renal clamping–declamping be­tween January 2004 and January 2007 at a ter­tiary care hospital in Tehran, Iran. The exclusion criteria were impairment in other organs such as kidney or heart at baseline. The Study was ap­proved by the local ethics committee of Shaheed Beheshti University of Medical Sciences. Neph­rologic side effects of this patient population were reported previously (8).

 

AAA repair was done via thoraco-lapa­rotomy or mid-line laparotomy. The aortic clamp was placed below the renal arteries, using a “clamp-and-sew” technique without protection of the kidneys apart from flushing the renal arteries with heparin. Possible intra-operative confounders for the renal outcome were noted: the duration of surgery, clamping time, peri-operative blood loss, episodes of hypotension (defined as a systolic blood pressure of <70 mm Hg lasting >5 minutes), transfusion requirements and body temperature.

 

Baseline data

Data on demographic variables (i.e. gen­der and age), and risk factors (i.e. hypertension, ischemic heart disease, diabetes mellitus and smoking) (9), the elective versus ruptured AAA surgery and also the surgical technique and tempo­rary decline in GFR (greater than 10% on the first 2 days and then returning to baseline value (10)) were registered.

 

Main Outcome

The main outcome (in-patient mortality) was any death occurring during the post-operative in-hospital stay. Causes of death were not included in this study on account of the fact that they had not been clearly recorded in the hospital database and autopsy had not been carried out.

 

Statistical Analyzes

All the computations were performed using SPSS software, version 13 (SPSS Inc., Chi­cago, IL) running under Windows 2000 Profes­sional (Microsoft Corp., Redmond, WA). The chi-square or Fisher exact test was employed for the categorical variables, when appropriate. Logistic regression analyzes were performed to investigate the independent value of the variables for in-pa­tient mortality. The data were presented as odds ratios (ORs) with 95% confidence intervals (CIs). P less than 0.05 was considered significant.

 

    Results                                                            

 

 Our sample population included 94 (88.7%) men. The patients’ age range was 38- 87 years, with a mean (SD) of 63.5± 11.6 years. The subjects were followed during their hospital stay for 7 ± 6 days (median= 5; inter-quartile range 4- 9 days), with a range of 1- 51 days.

   Table 1. The association between inpatient mortality and baseline data

 

Demographic data

Inpatient Death

 

 

n

%

Sig

Age

> 70

15

36.6

0.012

Up to 69

10

15.4

Sex

Male

22

23.4

0.574

Female

3

25.0

Risk factors

 

 

 

 

Ischemic Heart disease

No

17

21.5

0.353

Yes

6

31.6

Smoker

No

4

13.8

0.143

Yes

19

27.5

HTN

No

20

23.3

0.894

Yes

3

25.0

Leakage of Aneurism

Not present

16

18.2

0.004

Present

9

50.0

Diagnosis of AS

Not present

18

25.7

0.471

Present

7

19.4

Type of operation

Aortobiiliac

16

20.0

0.097

Aortoiliofemoral

5

55.6

Aortobifemoral

2

16.7

Tubular

2

50.0

 

 

 

A very high rate of inpatient mortality was seen (23.5%). Univariate analysis showed that mortality was higher in patients with age higher than 70 (36.6 vs. 15.4%, P= 0.012), aorta leakage before surgery (50.0% vs. 18.2%, P= 0.004)  and those who developed temporary worsening of the renal function (44.0% vs. 17.3%, P= 0.006). (Table 1)

 

The regression analysis showed that tem­porary renal dysfunction and the age over 70 years were independently associated with higher inpa­tient mortality. (Table 2)

 

Table 2. Predictors of inpatient mortality following aortic reconstruction

Sig.

95% C1 for OR

OR

 

 

Upper

Lower

 

 

0.037

9.214

1.071

3.141

Temporery worsening of renal functio

0.032

8.337

1.099

3.028

age higher than 70 year


 

     Discussion                                                     


In the present study, the inpatient mortal­ity rate was very high and alarming. In fact almost one of four procedures ends with inpatient death. This rate was affected by age higher than 70 years and temporary worsening of renal function after surgery.

The overall 23.6% mortality in this study is alarming and is higher in comparison to most of previous reports from other countries (11-16). This may be due to the fact that most previous studies have included only elective surgery, while we included also ruptured aneurysms, which is known to be associated with a higher mortality, up to 75% (17-27). In our study, this was confirmed in univariate analysis when mortality was doubled when ruptured aneurysm was the diagnosis, which is an emergency surgery indication.

 

In contrast with other cardiovascular dis­eases where rates of deaths have fallen (28), the mortality rate for AAA has risen over recent dec­ades. The high inpatient mortality has been at­tributed to high rate of post-surgery complications (2). The mortality highly depends on the experi­ence of surgeon and quality of health care ser­vices, and decreasing mortality rate can be achieved not only through an increase in experi­ence of the surgeons, but also the improvement in quality of operative and postoperative care (29).

 

Beside the link between high age and poor outcome which is in line with previous re­ports (30-34), patients with a temporary worsen­ing of renal function were more likely to have poor in-patient outcome. This finding from the study was reported elsewhere (8). Similar results have been reported from other studies. One study reported that the greatest mortality rate within 30 days was seen in patients with an increased serum creati­nine. In that study, renal function changes within 3 days after surgery were a strong predictor of peri-operative mortality (35). In another retro­spective cohort of patients who underwent elective open AAA surgery in a single center, negative impact of temporary worsening of the renal func­tion on long-term mor­tality has been reported (10).

 

It should be noticed that most previous studies have published 30 days outcome, here we reported inpatient outcome, which happened in a mean 7 days stay at hospital. Although the mor­tality rate is not much high after discharge with stable condition, but the 30 days mortality might be higher than the inpatient mortality(36). Unfortu­nately, similar to our previous report (8), we had not access to the data of survival after discharge to compute 30 days outcome. Other limitations of the present study with its relatively small number of patients are not only the retro­spective design but also not entering time of death to the analysis. The lack of availability of causes of death was another limitation of the study. An­other limitation was not considering long-term mortality.

In conclusion, in a tertiary hospital in Iran, inpa­tient mortality following reconstructive surgery of AAA is very high. Age over 70 and temporary worsening of the renal function are the associ­ated factors of the poor inpatient outcome.

 

Conflict of interest:

Authors declare no conflict of interest

 

 

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