How Many Patients With Infrarenal Aneurysms Are Candidates for Endovascular Repair?The Northern California Experience

Considerations for patients undergoing endovascular abdominal aortic aneurysm repair

Endovascular aneurysm repair has taken over open surgery as the primary strategy for treatment of patients with abdominal and thoracic aneurysms. The minimally invasive nature of these techniques requires alterations in preoperative workup, intraoperative management, and familiarity with unique complications that can occur. Familiarity from the anesthetic standpoint of endovascular techniques, including treatment of patients with fenestrated, chimney, snorkel, and periscope grafts, is necessary for the contemporary cardiac anesthesiologist.

Endovascular repair of abdominal aortic aneurysm using bifurcated stent-graft in a patient with complete occlusion from the common to the external iliac artery

Extensive iliofemoral occlusive disease can limit the use of endovascular aortic aneurysm repair (EVAR), and the treatment strategy varies depending on severity of the lesion. In cases of mild iliac artery (IA) stenosis, predilation using a balloon catheter before EVAR is relatively common, and for severe IA stenosis, the technique of internal endoconduits has been reported with good results. In contrast, EVAR using an aortouni-iliac stent graft with femorofemoral crossover bypass has traditionally been used for abdominal aortic aneurysm with IA occlusion. However, EVAR using a bifurcated stent graft has some clear advantages over aortouni-iliac stent grafts. In this report, we describe and discuss technical aspects and feasibility of chronically occluded iliac artery recanalization before EVAR to facilitate the use of bifurcated stent grafts in a patient with concomitant complete common to external IA occlusion.

Women with abdominal aortic aneurysms have more extensive aortic neck pathology

BACKGROUND

The proportion of women with abdominal aortic aneurysm (AAA) treated with endovascular aortic repair (EVAR) is lower than for open repair (OR). Unfavorable morphologic features for EVAR in women with AAA may explain this disproportion. The objective of this study was to identify morphologic features in AAA patients undergoing elective repair with special emphasis on gender differences.

METHODS

Patients undergoing elective repair from January 1, 2006 to December 31, 2008 at our university's vascular unit were included in this study. Computed tomography (CT) angiograms were analyzed. Morphologic features considered unfavorable for EVAR rather than open repair (OR) included: infrarenal aortic neck <15 mm; angulation >60°; circumferential neck thrombus; neck width >32 mm; iliac arteries <7.5 mm; or presence of bi-iliac aneurysms. Complex aortic neck was defined as a neck length of <15 mm and one or more of the other aortic neck exclusion criteria.

RESULTS

One hundred seventy-two patients, including 140 men and 32 women, were treated during the study period, which included 99 with OR (21 women, 78 men) and 73 with EVAR (11 women, 62 men). Morphologic unsuitability for EVAR was 44% (75 of 172) and was not statistically different between women and men [47% (15 of 32) vs. 43% (60 of 140), P = 0.70]. Aortic neck pathology was the dominating feature for unsuitability for EVAR (69 of 75, 92%), and 85 of 172 patients had an unsuitable aortic neck. This rate was not different between women and men [19 of 32 (59%) vs. 66 of 140 (47%), P = 0.24]. Iliac unsuitability rates were 11% (19 of 172) and were not different between women and men [4 of 32 (12%) vs. 15 of 140 (11%), P = 0.76]. In patients unsuitable for EVAR, the proximal aortic necks showed more extensive aortic neck pathology in women than in men [8 of 15 (53%) vs. 13 of 60 (22%), P = 0.02]. More men had only short neck pathology [22 of 60 (37%) vs. 1 of 15 (7%), P = 0.03].

CONCLUSIONS

Aortic neck pathology is the dominating cause of EVAR exclusion in both genders. A higher proportion of women have more pathologic neck anatomy. Future development of EVAR devices should focus on the complexity of the aortic neck, which will benefit all AAA patients, but especially women.

Correlation of CT aortography measurements of infrarenal aortic aneurysms and body mass index in preprocedural evaluation for endovascular repair

The aim of this study is to analyze the morphological differences of infrarenal aortic aneurysms and common iliac arteries that are important for endovascular management between patients of different body mass index using 64 slice multidetector row CT aortography. This was a multicenter study of 100 patients (50 Europeans and 50 Japanese). All patients had risk factors, manifest symptoms, and ultrasound verified aneurysmal dilation of the infrarenal aorta. All examinations were performed on the same CT platform using the same post-processing protocols. Due to the heterogeneity of the population, several statistical models were used. Significant differences were found in morphological parameters of infrarenal aorta in relation to BMI. In over one out of three patients with BMI less than 23, endovascular treatment is contraindicated due to the dimensions of the aneurysmal neck. Relative to BMI value, differences were found in transverse diameters of the medium part of the aneurysm and in the length of common iliac arteries. CT aortography performed on a 64 slice multidetector row CT platform provides precise and numerous data for the analysis of anatomical and pathological differences of infrarenal aortic aneurysms that are of crucial importance for the planning of treatment and the analysis of the differences relating to body habitus.

Postoperative pulmonary function after open abdominal aortic aneurysm repair in patients with chronic obstructive pulmonary disease: epidural versus intravenous analgesia

BACKGROUND

We reviewed our experience to determine the effect of epidural versus intravenous analgesia on postoperative pulmonary function and pain control in patients with chronic obstructive pulmonary disease (COPD) undergoing open surgery for abdominal aortic aneurysm.

METHODS

A retrospective study with prospective collection of data of 30 COPD patients undergoing open abdominal aortic aneurysm repair, during a 5-year period. Group I (n = 16) was operated under combined general and epidural anesthesia and epidural analgesia; group II (n = 14), under general anesthesia and intravenous analgesia. All patients performed pulmonary function tests (PFTs) preoperatively and during postoperative days 1 and 4. Pain assessment was performed on all patients during rest and activity on postoperative days 1, 2, and 4 by using the visual analog scale. Data were recorded for PFTs, postoperative pain, length of hospital stay, length of ICU stay, and postoperative pulmonary morbidity, including atelectasis and pulmonary infections.

RESULTS

There was no in-hospital mortality. Hospital stay was similar between the two groups (group I: 7.1 ± 1.0, group II: 7.5 ± 1.1). Group I patients showed significantly increased postoperative PFT values compared with group II patients at all time points (postoperative day 1: FEV(1)(%): 32.3 ± 4.4 vs. 27.1 ± 1.6, p = 0.007, FVC(%): 35.4 ± 8,5 vs. 28.3 ± 2.3, p = 0.035; postoperative day 4: FEV(1)(%): 50.4 ± 6.8 vs. 41.9 ± 6.8, p = 0.017, FVC(%): 51.3 ± 8.3 vs. 43.0 ± 7.9, p = 0.046). However, postoperative clinical pulmonary morbidity was not different between groups. Group I patients showed significantly reduced postoperative pain at all time points compared with group II patients. These differences were more pronounced during postoperative days 1 and 2, both at rest (visual analog score: 1.1 ± 0.9 vs. 2.6 ± 1.6, p = 0.02 and 0.7 ± 0.8 vs. 1.9 ± 1.1, p = 0.021, respectively) and during activity (2.3 ± 0.8 vs. 4.0 ± 1.7, p = 0.013 and 1.6 ± 0.7 vs. 2.8 ± 1.2, p = 0.019, respectively).

CONCLUSIONS

Epidural anesthesia and postoperative epidural analgesia improve the postoperative respiratory function, compared with general anesthesia and systemic analgesia, and reduce postoperative pain as well, in COPD patients undergoing elective infrarenal abdominal aortic aneurysm repair.

Should usual criteria for intervention in abdominal aortic aneurysms be "downsized," considering reported risk reduction with endovascular repair?

Two randomized trials have demonstrated the safety of waiting until abdominal aortic aneurysm (AAA) diameter reaches 5.5 cm for repair in most patients. Other recent randomized trials have demonstrated lower perioperative mortality and morbidity with endovascular aneurysm repair (EVAR) compared to open surgery. Therefore, it is logical to assume that endovascular repair may change the appropriate threshold for intervention. However, endovascular repair is not as durable as open surgery and is associated with ongoing risks of rupture and reintervention. Decision analysis based on data available in 1998 showed that endovascular repair should not change the threshold for intervention. Since that time retrospective data have emerged to suggest that outcomes with endovascular repair are improved in smaller AAAs, although this may simply represent selection bias and the natural history of small AAAs. Randomized trials are appropriate to determine whether improved endovascular outcomes in small AAAs reduce late rupture and reintervention enough to justify early intervention in patients with appropriate anatomy. In the absence of data from these trials, the threshold for intervention should not be changed.

Comparison of endovascular aneurysm repair with open repair in patients with abdominal aortic aneurysm (EVAR trial 1), 30-day operative mortality results: randomised controlled trial

BACKGROUND

Endovascular aneurysm repair (EVAR) is a new technology to treat patients with abdominal aortic aneurysm (AAA) when the anatomy is suitable. Uncertainty exists about how endovascular repair compares with conventional open surgery. EVAR trial 1 was instigated to compare these treatments in patients judged fit for open AAA repair.

METHODS

Between 1999 and 2003, 1082 elective (non-emergency) patients were randomised to receive either EVAR (n=543) or open AAA repair (n=539). Patients aged at least 60 years with aneurysms of diameter 5.5 cm or more, who were fit enough for open surgical repair (anaesthetically and medically well enough for the procedure), were recruited for the study at 41 British hospitals proficient in the EVAR technique. The primary outcome measure is all-cause mortality and these results will be released in 2005. The primary analysis presented here is operative mortality by intention to treat and a secondary analysis was done in per-protocol patients.

FINDINGS

Patients (983 men, 99 women) had a mean age of 74 years (SD 6) and mean AAA diameter of 6.5 cm (SD 1). 1047 (97%) patients underwent AAA repair and 1008 (93%) received their allocated treatment. 30-day mortality in the EVAR group was 1.7% (9/531) versus 4.7% (24/516) in the open repair group (odds ratio 0.35 [95% CI 0.16-0.77], p=0.009). By per-protocol analysis, 30-day mortality for EVAR was 1.6% (8/512) versus 4.6% (23/496) for open repair (0.33 [0.15-0.74], p=0.007). Secondary interventions were more common in patients allocated EVAR (9.8% vs 5.8%, p=0.02).

INTERPRETATION

In patients with large AAAs, treatment by EVAR reduced the 30-day operative mortality by two-thirds compared with open repair. Any change in clinical practice should await durability and longer term results.