Improved results in the management of ruptured abdominal aortic aneurysm may not be on the basis of endovascular aneurysm repair alone

Systematic review and meta-analysis of the risk of bowel ischemia after ruptured abdominal aortic aneurysm repair

OBJECTIVE

Outcomes after repair of ruptured abdominal aortic aneurysm (RAAA) have improved in the last decade. It is unknown whether this has resulted in a reduction of postoperative bowel ischemia (BI). The primary objective was to determine BI prevalence after RAAA repair. Secondary objectives were to determine its major sequelae and differences between open repair (OR) and endovascular aneurysm repair (EVAR).

METHODS

This systematic review (PROSPERO CRD42017055920) followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines. MEDLINE and Embase were searched for studies published from 2005 until 2018. The methodologic quality of observational studies was assessed with the Methodological Index for Non-Randomized Studies (MINORS) tool. The quality of the randomized controlled trials (RCTs) was assessed with the Cochrane Collaboration's tool for assessing risk of bias. BI prevalence and rates of BI as cause of death, reoperation, and bowel resection were estimated with meta-analyses with a random-effects model. Differences between OR and EVAR were estimated with pooled risk ratios with 95% confidence intervals (CIs). Changes over time were assessed with Spearman rank test (ρ). Publication bias was assessed with a funnel plot analysis.

RESULTS

A total of 101 studies with 52,670 patients were included; 72 studies were retrospective cohort studies, 14 studies were prospective cohort studies, 12 studies were retrospective administrative database studies, and 3 studies were RCTs. The overall methodologic quality of the RCTs was high, but that of observational studies was low. The pooled prevalence of BI ranged from of 0.08 (95% CI, 0.07-0.09) in database studies to 0.10 (95% CI, 0.08-0.12) in cohort studies. The risk of BI was higher after OR than after EVAR (risk ratio, 1.79; 95% CI, 1.25-2.57). The pooled rate of BI as cause of death was 0.04 (95% CI, 0.03-0.05), and that of BI as cause of reoperation and bowel resection ranged between 0.05 and 0.07. BI prevalence did not change over time (ρ, -0.01; P = .93). The funnel plot analysis was highly suggestive of publication bias.

CONCLUSIONS

The prevalence of clinically relevant BI after RAAA repair is approximately 10%. Approximately 5% of patients undergoing RAAA repair suffer from severe consequences of BI. BI is less prevalent after EVAR than after OR.

A systematic review and meta-analysis of the use of resuscitative endovascular balloon occlusion of the aorta in the management of major exsanguination

BACKGROUND

Circulatory collapse is a leading cause of mortality among traumatic major exsanguination and in ruptured aortic aneurysm patients. Approximately 40% of patients die before hemorrhage control is achieved. Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an adjunct designed to sustain the circulation until definitive surgical or endovascular repair. A systematic review was conducted for the current clinical use of REBOA in patients with hemodynamic instability and to discuss its potential role in improving prehospital and in-hospital outcome.

METHODS

Systematic review and meta-analysis (1900-2017) using MEDLINE, Cochrane, EMBASE, Web of Science and Central and Emcare using the keywords "aortic balloon occlusion", "aortic balloon tamponade", "REBOA", and "Resuscitative Endovascular Balloon Occlusion" in combination with hemorrhage control, hemorrhage, resuscitation, shock, ruptured abdominal or thoracic aorta, endovascular repair, and open repair. Original published studies on human subjects were considered.

RESULTS

A total of 490 studies were identified; 89 met criteria for inclusion. Of the 1436 patients, overall reported mortality was 49.2% (613/1246) with significant differences (p < 0.001) between clinical indications. Hemodynamic shock was evident in 79.3%, values between clinical indications showed significant difference (p < 0.001). REBOA was favored as treatment in trauma patients in terms of mortality. Pooled analysis demonstrated an increase in mean systolic pressure by almost 50 mmHg following REBOA use.

CONCLUSION

REBOA has been used in trauma patients and ruptured aortic aneurysm patients with improvement of hemodynamic parameters and outcomes for several decades. Formal, prospective study is warranted to clarify the role of this adjunct in all hemodynamic unstable patients.

Contemporary outcomes for ruptured abdominal aortic aneurysms using endovascular balloon control for hypotension

OBJECTIVE

Ruptured abdominal aortic aneurysm (rAAA) continues to portend significant mortality, despite ruptured endovascular aneurysm repair (rEVAR), enhanced perioperative care, and endovascular balloon control (EBC) for hypotension. We review our academic institution's experience using a protocol of EBC for all hypotensive patients, irrespective of type of repair.

METHODS

A retrospective review was conducted of 66 cases of rAAA treated at a single academic institution from 2007 to 2016 using EBC for hypotensive patients. Demographics, comorbidities, intraoperative parameters, and clinical outcomes were recorded. Patients were studied with respect to hemodynamic status, rEVAR, or ruptured open aortic repair in the setting of EBC for hypotension.

RESULTS

rEVAR was performed in 43 patients (65%) and ruptured open aortic repair in 23 patients (35%). rAAA was treated in 51 men (77%). Mean rAAA size was 7.6 mm, and mean age of the patients was 73 years. Perioperative survival was 82%. Overall survival at 30 days, 1 year, and 5 years was 71%, 65%, and 52%. Blood transfusion and severe hypotension were significant predictors of mortality at 30 days on multivariable analysis (odds ratio of 1.2 [P = .08] and 39 [P = .03], respectively). Severe hypotension was defined as a mean arterial blood pressure <65 mm Hg and vasopressor use and was present in 59% of the cohort. Normotension was defined as an absence of these conditions and was present in 12%, with 29% of patients exhibiting moderate hypotension. There was no difference in 30-day survival between normotensive and moderately hypotensive patients. The 30-day survival for severely hypotensive patients was 61% vs 85% for moderately hypotensive patients (P = .003), with a significant difference between groups that persisted at 1 year (85% vs 51%; P = .008) and 5 years (66% vs 51%; P = .017).

CONCLUSIONS

Good midterm outcomes for moderately hypotensive and normotensive patients can be obtained using an EBC protocol for hypotension with a regionalized transport system directly to the operating room. Severely hemodynamically unstable rAAA patients still pose a significant challenge despite mitigation of hypotension by EBC, suggesting that survival may be compromised by factors other than hypotension alone. We still advocate for the use of EBC for all hypotensive patients as part of a defined rAAA protocol before definitive repair.

Complications and Perioperative Management of Patients Undergoing Thoracic Endovascular Aortic Repair

Endovascular treatments have become increasingly common for patients with a variety of thoracic aortic pathologies. Although considered less invasive than traditional open surgical approaches, they are nonetheless complex procedures. Patients undergo manipulation of an often calcified aorta near the origin of the carotid and subclavian vessels and have stents placed in a curved vessel adjacent to a perpetually beating heart. These stents can obstruct blood flow to the spinal cord, induce an inflammatory response, and in rare cases erode into the adjacent trachea or esophagus. Renal complications range from contrast-induced nephropathy to hypotension and ischemia to dissection. Emboli can lead to strokes and mesenteric ischemia. These patients have complex medical histories, and skilled perioperative management is critical to achieving the best clinical outcomes. Here, we review the medical management of the most common complications in these patients including stroke, spinal cord ischemia, renal injury, retrograde dissections, aortoesophageal and aortobronchial fistulas, postimplantation syndrome, mesenteric ischemia, and endograft failure.