Medical treatment of small abdominal aortic aneurysm

Conventional open repair or endovascular aneurysm repair is indicated for infrarenal abdominal aortic aneurysm (AAA) when the diameter of the latter is ≥ 5.5 cm. This therapeutic strategy is based on results of randomized trials of open repair versus ultrasound surveillance of small AAA (<5.5 cm). Studies of screening for AAA have shown that >90% of aneurysms detected are small aneurysms (<5.5 cm). Despite the low annual risk of rupture of these aneurysms, patients with small AAA are left with a potentially life-threatening disease for which no immediate treatment is available. Hence, medical treatment directed at limiting the expansion of small AAA has emerged as an alternative therapeutic strategy. Randomized trials of doxycycline, roxithromycin, and propranolol in patients with small AAA have been published. The results of the doxycycline and roxithromycin trials suggest that both medications can limit AAA expansion, especially during the first year of treatment. Propranolol did not limit AAA expansion, and the trials were stopped because of its serious side effects. In other studies, statins and indomethacin have also been shown to limit AAA expansion. However, these studies were observational with relatively small numbers of patients. Thus, large randomized controlled trials with long follow-up are needed to objectively assess the efficacy of medications that have shown potential in limiting AAA expansion. In addition, recent evidence of regression of AAA in experimental animal models is likely to change our concepts of the molecular pathogenesis of AAA, and could make medical treatment of small AAA a possibility.

Outcome of open versus endovascular revascularization for chronic mesenteric ischemia: review of comparative studies

Chronic mesenteric ischemia is a rare disorder that has traditionally been treated with open surgical revascularization (OR). Endovascular revascularization (ER) has recently gained popularity as an alternative modality of treatment; however, OR is still predominantly used. This study aimed at comparing the outcomes of these two treatment modalities. The literature was searched using the MEDLINE database through the PubMed search engine for relevant articles that compared the outcomes after OR and ER for chronic mesenteric ischemia. Review of the selected articles revealed that patients had lower postoperative mortality and morbidity, and shorter intensive care unit and hospital stay after ER. However, early and long-term symptomatic relief and significantly lower restenosis rate were characteristic of OR. Although no level 1 evidence governs the treatment of chronic mesenteric ischemia, the durability and efficacy of OR is such that this modality should remain the procedure of choice for patients who are fit or whose fitness could be improved before surgery. For unfit patients, or those with short life expectancy, ER is preferable owing to its minimally invasive nature and reduced postoperative mortality and morbidity. Randomized controlled studies are needed to compare the long-term durability and efficacy of ER to those of OR.

Endovascular proximal control of ruptured abdominal aortic aneurysms: the internal aortic clamp

Ruptured abdominal aortic aneurysm (RAAA) is the most common and devastating complication affecting a patient with abdominal aortic aneurysm (AAA). Despite advances in surgery and critical care, the mortality rate associated with RAAA remains largely unchanged. Emergency open repair is the gold standard conventional treatment of RAAA but is associated with a high mortality rate. The physiologic challenges associated with general anaesthetic induction such as loss of the sympathetic vasoconstrictor tone with consequent hypotension, and the anatomic challenges associated with external aortic cross-clamping such as calcification, friability, or poor visualisation of the aneurysm neck, have led to the adoption of endovascular techniques in the surgical treatment of RAAA. Promising results of endovascular repair of ruptured abdominal aortic aneurysm (REVAR) have been reported. In addition, the provision of endovascular aortic control by inflating a compliant aortic occlusion balloon (AOB) proximal to the ruptured aneurysm, as an internal aortic clamp, has been successfully used in haemodynamically unstable patients undergoing either REVAR or emergency open repair of RAAA. An AOB is inserted under local anaesthesia and can be introduced through either the transbrachial or the transfemoral routes, each with its own advantages and disadvantages. This review aimed at providing an up-to-date overview of the current knowledge concerning endovascular proximal aortic control using an AOB with emphasis on the rationale, position, benefits, and drawbacks of its use.