Intravenous heparin during ruptured abdominal aortic aneurysmal repair

Background

An abdominal aortic aneurysm (AAA) is a swelling (aneurysm) of the aorta, the main blood vessel that leads away from the heart down through the abdomen to the rest of the body, and can develop in both men and women. A growing aneurysm can lead to rupture. The rupture of an AAA leads to massive blood loss and is frequently fatal.

There have been enormous advances in managing AAAs in the last decade but ruptured AAAs (rAAAs) still have an unchanged high death rate. Intravenous heparin provides a protective effect against heart and blood clot problems. This practice has not gained widespread acceptance for emergency repairs of rAAA even though a reduction in death and morbidity has been demonstrated in surgical repair that is scheduled in advance because it does not involve a medical emergency (elective repair).

Study characteristics

We searched the medical literature for all randomised controlled trials (RCTs) and controlled clinical trials (CCTs) of intravenous heparin in rAAA repairs (current until December 2015).

Key results

We found no RCTs or CCTs of intravenous heparin in rAAA repairs that satisfied the inclusion criteria.

Quality of the evidence

We found no RCTs or CCTs of intravenous heparin in rAAA repairs (including parallel designs). Therefore, we were unable to assess the effect of intravenous heparin on all-cause mortality and incidence of general arterial disease, for example, cardiovascular, cerebral, pulmonary and renal pathologies in ruptured abdominal aortic aneurysm (rAAA) management in people undergoing an emergency repair. It is clear that an RCT is needed to address this question in rAAA management as there is no high quality evidence.

Authors' conclusions: 

We identified no RCTs or CCTs of intravenous heparin in rAAA repairs (including parallel designs). Therefore, we were unable to assess the effect of intravenous heparin on all-cause mortality and incidence of general arterial disease, for example, cardiovascular, cerebral, pulmonary and renal pathologies in rAAA management in people undergoing an emergency repair. It is clear that an RCT is needed to address this question in rAAA management as there is no high quality evidence.

Read the full abstract...
Background: 

There have been enormous advances in the screening, diagnosis, intervention and overall prognosis of abdominal aortic aneurysms (AAAs) in the last decade, but despite these, ruptured AAAs (rAAAs) still cause around 3500 to 6000 deaths in England and Wales each year. Open repair remains standard treatment for rAAA in most centres but increasingly endovascular aneurysm repair (EVAR) is being adopted. This has a 30-day postoperative mortality of 40%. This has remained static despite surgical, anaesthetic and critical care advances.

One significant change to current practice for elective repairs of AAAs, as opposed to emergency repairs of rAAAs, has been the introduction of intravenous heparin. This provides a protective effect against cardiac and thrombotic disease in the postoperative period. This practice has not gained widespread acceptance for emergency repairs of rAAA even though a reduction in mortality and morbidity has been demonstrated in elective repairs.

Objectives: 

The primary objective was to assess the effect of intravenous heparin on all-cause mortality in ruptured abdominal aortic aneurysm (rAAA) management in people undergoing an emergency repair.

The secondary objectives were to assess the effect of intravenous heparin in rAAA management on the incidence of general arterial disease, for example, cardiovascular, cerebral, pulmonary and renal pathologies, in people undergoing emergency repair.

Search strategy: 

The Cochrane Vascular Information Specialist (CIS) searched the Specialised Register (December 2015). In addition the CIS searched CENTRAL;2015, Issue 11). The CIS searched clinical trials registries for details of ongoing or unpublished studies.

Selection criteria: 

We sought all published and unpublished randomised controlled trials (RCTs) and controlled clinical trials (CCTs) of intravenous heparin in rAAA repairs (including parallel designs).

Data collection and analysis: 

Two review authors independently assessed studies identified for potential inclusion in the review. We used standard methodological procedures in accordance with the Cochrane Handbook for Systematic Review of Interventions.

Main results: 

We identified no RCTs or CCTs that satisfied the inclusion criteria.

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