ELECTIVE OPEN REPAIR OF ABDOMINAL AORTIC ANEURYSMS (AAA):
A SYSTEMATIC REVIEW OF RISK FACTORS FOR ASSOCIATED MORBIDITY AND MORTALITY
Ana Luisa Pinto, Catarina Machado, Filipa Gomes, Hugo Sousa, José Henrique Messias, Joana Teixeira, Luís Miguel Lázaro, Maria Filipa Figueiredo, Miguel Quinta e Costa, Rafaela Parreira, Sérgio Cardoso, Silvia Farraposo, Sofia Figueiredo.
Professor Doutor Sérgio Sampaio,
1º Ano - Turma 5, Mestrado Integrado em Medicina da FMUP
Abstract:
Keywords: AAA, Abdominal Aortic Aneurysms; Elective Open Repair Surgery; Risk factors; Morbidity; Mortality.
INTRODUCTION
A common site for an aortic aneurysm is the part of the vessel that is immediately below the renal arteries but above the iliac arteries, known as Abdominal Aortic Aneurysm (AAA). The standard conceptualization accepted by medical community refers an aneurysm as an abnormal widening of an artery with an increment of 1.5-folds the normal diameter. Usually, it causes the weakening of tunica media, and consequently the stretching of the tunica adventitia and/or the tunica intima.
There are several risk factors for AAA development, namely: smoking, diabetes, elevated cholesterol, hypertension, atherosclerosis and familiar history. The incidence and prevalence of AAA also increases with age, rarely develops before the age of 50 and are much more common in men. Several studies have referred deficiencies on matrix metalloproteinases (MMPs) and plasminogen activators as contributors to aneurysms development, by providing susceptible substrates on which atherosclerosis and/or hypertension could weaken the aortic wall.
The most common treatments for AAA are endovascular repair and open repair. An open repair is an invasive surgical procedure on which an incision is made through the abdomen to expose the abdominal aorta and gain access to the aneurysm. A prosthetic tube-like graft with the size and shape of the healthy aorta is surgically sewn into place in order to repair the aneurysm. There are two surgical approaches to expose the aorta for repair: transperitoneal approach which involves gaining access to the AAA via a midline abdominal incision; and left retroperitoneal approach where the incision gains access to the AAA towards the left side of the abdomen. As an aneurysm grows progressively, rupture can occur at any moment, and when that happens, the intervention is called emergency open repair. However, if an aneurysm is detected in an early stage of development, the treatment is called elective open repair.
As any surgery, complete recovery after open repair may require up to 3 months and may be faced with some postoperative complications: cardiac events, haemorrhage, pulmonary insufficiency, renal failure, gastrointestinal ischemia and/or dysfunction, erectile dysfunction and graft infection. AAA repair is a technically difficult procedure with a relatively high mortality rate.
Considering all these data, we aimed to summarize the risk factors for AAA development and the postoperative complications associated with morbidity and mortality after elective open repair. Therefore, we also aimed to compare mortality rates and risk factors associated to AAA.
MATERIAL AND METHODS
Articles search
All studies to consider were selected from a PUBMED/Medline database search using the following query: (("mortality"[Subheading] OR "mortality"[MeSH Terms] OR mortality[Text Word]) AND ("abdominal aortic aneurysm"[Text Word] OR "aortic aneurysm, abdominal"[MeSH Terms] OR aaa[Text Word]) AND elective[All Fields] AND open[All Fields]) AND ((("wound healing"[TIAB] NOT Medline[SB]) OR "wound healing"[MeSH Terms] OR repair[Text Word]) OR ("surgery"[Subheading] OR "operative surgical procedures"[Text Word] OR "surgical procedures, operative"[MeSH Terms] OR "surgery"[MeSH Terms] OR surgery[Text Word])) NOT endovascular[All Fields])). Furthermore, the references listed on every articles obtained from the previous search will also be considered.
Inclusion/Exclusion Criteria
All original published studies were considered for analysis and further excluded by several factors, namely: language (others than English, French, Spanish or Portuguese) (n=???); other types of articles than data, such as reviews, letter to editor or comments (n=???); and all other articles contemplating emergency open AAA repair (n=???).
Data extraction and Statistical Analysis
Included studies were revised by all authors, in order to extract the necessary information to perform the analysis (n=…). Statistical analysis will be used to summarize the general observations from all studies (…).
RESULTS
DISCUSSION
REFERENCES
[1] / http://www.medifocushealth.com[2] / http://www.vascularweb.org
(ref. Robbins, Pathologic Basis of Disease, Chapter 12, p.71-74)
Figure 1: Abdominal Aortic Aneurysm representation [2].
Figure 2: Open Repair surgery – sewing of a prosthetic tube-like graft [2].
Complication / DescriptionCardiac Events / Most common postoperative complication.
Hemorrhage / The second most common complication and often due to technical difficulties or errors.
Pulmonary Insufficiency / Frequent complication on smoking and chronic obstructive pulmonary diseased (COPD) patients. This risk factor can be somewhat reduced if patients stop smoking several weeks prior to surgery.
Renal Failure / Renal failure is related primarily to procedures during surgery (e.g., clamping of the renal arteries during surgery and use of radiographic contrast dyes).
Gastrointestinal Ischemia and/or Dysfunction / Temporary dysfunction or paralysis of the small or large intestines often due to manipulation of the intestines during surgery or fluid retention.
Erectile Dysfunction / Most likely because of autonomic nerve injury and pelvic blood flow changes.
Graft Infection / This may occur months to years following surgery and is associated with significant morbidity and mortality. Prophylactic use of antibiotics prior to surgery is helpful in reducing the risk of this complication.
Table 1: Open Repair surgery complications.
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