Quantification of mortality risk after abdominal aortic aneurysm repair

BACKGROUND: The study was designed to evaluate the Acute Physiology And Chronic Health Evaluation (APACHE) II risk scoring system in abdominal aortic aneurysm (AAA) surgery. The aim was to create an APACHE-based risk stratification model for postoperative death. METHODS: Prospective postoperative APACHE II data were collected from patients undergoing AAA repair over a 9-year interval from 24 intensive care units (ICUs) in the Thames region. A multilevel logistic regression model (APACHE-AAA) for in-hospital mortality was developed to adjust for both case mix and the variation in outcome between ICUs. RESULTS: A total of 1896 patients were studied. The in-hospital mortality rate among the 1289 patients who had elective AAA repair was 9.6 (95 per cent confidence interval (c.i.) 8.0 to 11.2) per cent and that among the 605 patients who had an emergency repair was 46.9 (95 per cent c.i. 43.0 to 50.9) per cent. Four independent predictors of death were identified: age (odds ratio (OR) 1.05 (95 per cent c.i. 1.03 to 1.07) per year increase), Acute Physiology Score (OR 1.14 (95 per cent c.i. 1.12 to 1.17) per unit increase), emergency operation (OR 4.86 (95 per cent c.i. 3.64 to 6.52)) and chronic health dysfunction (OR 1.43 (95 per cent c.i. 1.04 to 1.97)). The APACHE-AAA model was internally valid, as shown by calibration (Hosmer-Lemeshow C statistic: chi(2) = 6.14, 8 d.f., P = 0.632), discrimination properties (area under receiver-operator characteristic curve 0.845) and subgroup analysis. There was no significant variation in outcome between hospitals. CONCLUSION: APACHE-AAA was shown to be an accurate risk-stratification model that could be used to quantify the risk of death after AAA surgery. It might also be used to determine the relative impact of ICU over high-dependency unit care.     

Single versus multi-specialty operative teams: association with perioperative mortality after endovascular abdominal aortic aneurysm repair

Endovascular abdominal aortic aneurysm repair (EVAR) requires both endovascular and open surgical skills. Although usually performed by a single operating specialist, EVAR may alternatively involve multiple teams from different specialties performing separate procedural components. We examined the relative frequencies of single versus multi-specialty EVAR in the 2005 to 2008 American College of Surgeons National Surgical Quality Improvement Participant Use Datafile and explored the influence of multi-specialty EVAR on 30-day mortality. EVARs were identified and classified as single or multiple-specialty procedures based on Current Procedural Terminology codes. Baseline and procedural characteristics were compared using χ(2) or Fisher's exact test for categorical variables and t test for continuous variables. The association between multi-specialty EVAR and 30-day mortality was examined using a multivariate logistic regression model. Of 7269 EVAR patients identified, 7086 were single and 183 were multi-specialty. Multi-specialty patients had higher frequency of brachial or iliac artery exposure and longer operative times, but were otherwise similar in baseline and procedural characteristics. In the multivariate model, multi-specialty EVAR was associated with increased risk of 30-day mortality (odds ratio 2.35; 95% confidence interval 1.08-5.11; P value 0.031). Multi-specialty participation in EVAR procedures is associated with significantly higher 30-day mortality. Further research is warranted to determine whether multi-specialty participation reflects provider experience, institutional protocols, procedural complexity, non-surgical or other factors.     

Sex differences in perioperative outcomes after complex abdominal aortic aneurysm repair

ObjectiveFemale sex is associated with worse outcomes after infrarenal abdominal aortic aneurysm (AAA) repair. However, the impact of female sex on complex AAA repair is poorly characterized. Therefore, we compared outcomes between female and male patients after open and endovascular treatment of complex AAA.MethodsWe identified all patients who underwent complex aneurysm repair between 2011 and 2017 in the American College of Surgeons National Surgical Quality Improvement Program targeted vascular module. Complex repairs were defined as those for juxtarenal, pararenal, or suprarenal aneurysms. We compared rates of perioperative adverse events between female and male patients stratified by open AAA repair and endovascular aneurysm repair (EVAR). We calculated propensity scores and used inverse probability-weighted logistic regression to identify independent associations between female sex and our outcomes.ResultsWe identified 2270 complex aneurysm repairs, of which 1260 were EVARs (21.4% female) and 1010 were open repairs (30.7% female). After EVAR, female patients had higher rates of perioperative mortality (6.3% vs 2.4%; P = .001) and major complications (15.9% vs 7.6%; P < .001) compared with male patients. In contrast, after open repair, perioperative mortality was not significantly different (7.4% vs 5.6%; P = .3), and the rate of major complications was similar (29.4% vs 27.4%; P = .53) between female and male patients. Furthermore, even though perioperative mortality was significantly lower after EVAR compared with open repair for male patients (2.4% vs 5.6%; P = .001), this difference was not significant for women (6.3% vs 7.4%; P = .60). On multivariable analysis, female sex remained independently associated with higher perioperative mortality (odds ratio [OR], 2.5; 95% confidence interval [CI], 1.3-4.9; P = .007) and major complications (OR, 2.0; 95% CI, 1.3-3.2; P = .002) in patients treated with EVAR but showed no significant association with mortality (OR, 0.9; 95% CI, 0.5-1.6; P = .69) or major complications (OR, 1.1; 95% CI, 0.8-1.5; P = .74) after open repair. However, the association of female sex with higher perioperative mortality in patients undergoing complex EVAR was attenuated when diameter was replaced with aortic size index in the multivariable analysis (OR, 1.9; 95% CI, 0.9-3.9; P = .091).ConclusionsFemale sex is associated with higher perioperative mortality and more major complications than for male patients after complex EVAR but not after complex open repair. Continuous efforts are warranted to improve the sex discrepancies in patients undergoing endovascular repair of complex AAA.     

A statewide experience with endovascular abdominal aortic aneurysm repair: rapid diffusion with excellent early results

OBJECTIVE: The purpose of this study was to compare survival and outcomes of endovascular versus open repair of abdominal aortic aneurysms (AAAs) in New York State (NYS). METHODS: We used the NYS discharge dataset Statewide Planning and Research Cooperative System (SPARCS) to analyze the outcomes of elective admission for nonruptured (International Classification of Diseases-9th revision [ICD-9] 441.4) open aneurysm repair (38.44) and endovascular aneurysm repair (39.71) during the years 2000-2002. The ICD-9 code for endovascular repair was introduced in late 2000, thus capturing 3 months of empiric data for 2000. RESULTS: There has been a significant increase in the number of AAA procedures performed in NYS (comparing before and after 2000: average, 1419 vs 1701; P =.0001), temporally coinciding with the implementation of training programs after US Food and Drug Administration approval of endovascular grafts and the new payment code. From 2000 to 2002 the number of NYS hospitals performing endovascular repairs increased from 24 to 60. By 2002 there were more endovascular repairs being performed than open repairs (871 vs 783). The target population for these surgical interventions showed interesting differences. In 2002, women had a 43% chance of receiving an endograft, whereas men had a 55% probability. The use of endovascular repair over the observation period was relatively constant in patients younger than 65 years. In patients older than 65 years, and especially those older than 75 years, endovascular use increased substantially, so that by 2002 older patients were more likely to undergo endovascular repair than open repair. Patients who underwent endovascular repair had significantly more hypertension, coronary artery disease, diabetes, and hyperlipidemia than did patients who underwent open repair. Yet the mean length of stay for endovascular procedures was approximately 3.6 days, and for open procedures was about 10.3 days, across all 3 years (P = <.0001). Moreover, patients who underwent endovascular repair had statistically fewer postoperative complications and significantly lower mortality. In-hospital mortality in 2001 was 3.55% for open repair and 1.14% for endovascular repair (P =.0018), and in 2002 these rates were 4.21% versus 0.8% (P <.0001), respectively. CONCLUSION: This dataset suggests that endovascular AAA repairs are being performed in a patient population with a higher frequency of comorbidities. However, endovascular repairs still are associated with significantly lower in-hospital mortality, fewer postoperative complications, and a dramatically shorter length of stay. These results suggest that, despite the rapid diffusion of this new technique, early perioperative outcomes may be superior to those with conventional open repair. However, prospective clinical studies are needed to confirm these insights, and such studies may require the infrastructure of consortia of hospitals or society-based registries.     

Endovascular abdominal aortic aneurysm repair: a community hospital's experience

Endovascular abdominal aortic aneurysm repair (EVAR) has become the first-line approach for the treatment of abdominal aortic aneurysms. Outcomes outside of tertiary care settings remain unknown. The purpose of this study is to report the midterm outcomes of EVAR in a community hospital. A retrospective review of 75 elective, consecutive EVARs performed at a single nonacademic community hospital was performed. There were no conversions to open repair during or after endovascular repair. The mean follow-up was 18 months. There were no postoperative ruptures or aneurysm-related deaths. At 24 months, freedom from aneurysm-related death was 100%, freedom from secondary interventions was 91%, and freedom from endoleak was 69%. EVAR in the community setting is a safe and durable procedure, even in a medically high-risk population. Comparable outcomes can be achieved to tertiary care centers, in carefully selected patients with favorable anatomy.     

Ruptured abdominal aortic aneurysm after endovascular aortic aneurysm repair

In treating uncomplicated abdominal aortic aenurysm, endovascular aortic aneurysm repair (EVAR) has been employed as a good alternative to open repair with low perioperative morbidity and mortality. However, the aneurysm can enlarge or rupture even after EVAR as a result of device failure, endoleak, or graft migration. We experienced two cases of aneurismal rupture after EVAR, which were successfully treated by surgical extra-anatomic bypass.     

Renin-angiotensin system blockade does not attenuate abdominal aortic aneurysm growth,rupture rate,or perioperative mortality after elective repair

Objective

The objective of this study was to summarize the literature regarding the effects of renin-angiotensin system blockade (RASB) using angiotensin-converting enzyme inhibitors (ACEis) or angiotensin receptor blockers (ARBs) on human abdominal aortic aneurysm (AAA) growth, rupture, and perioperative mortality.

Risk-adjusted analysis of early mortality after ruptured abdominal aortic aneurysm repair

PURPOSE: Ruptured abdominal aortic aneurysms (RAAAs) continue to result in early mortality in up to 50% of patients. Additionally, it remains difficult to compare outcomes given the variability in patient comorbidities and presentation. The purpose of this study was to describe an instrument that permits the prospective analysis of outcomes after RAAA repair while adjusting for the variability in preoperative risk. METHODS: Consecutive patients undergoing attempted open RAAA repair over a 5-year period (1999 to 2003) at our center were reviewed. Thirty-day or in-hospital mortality was the main outcome variable. Preoperative mortality risk was estimated for each patient by using a validated modification of the POSSUM scoring system (V-POSSUM). A risk-adjusted cumulative sum method (RA-CUSUM) was used to compare observed versus predicted outcomes by assigning a risk-adjusted score, based on log-likelihood ratios, to each patient. These scores were sequentially plotted with preset control limits to allow for "signaling" when results were substantially different from expected (doubling or halving of odds ratios). RESULTS: A total of 136 patients were reviewed, with an early mortality rate of 45.6%. V-POSSUM scores were accurate in predicting mortality for the entire cohort, with an observed-to-predicted mortality ratio of 0.92 (P = .80). Each patient's risk-adjusted score was plotted sequentially. In one segment of the resulting plot, the graph adopted a negative slope and crossed the lower control limit, indicating improved results compared with predicted. CONCLUSIONS: V-POSSUM scores in this series accurately predicted early mortality after RAAA surgery. The RA-CUSUM method allows for the prospective evaluation of outcomes, while taking into account patient variability. In the current study, this resulted in the identification of a series of patients who had improved outcomes compared with predicted.     

腹主动脉瘤腔内修复术单中心治疗经验

目的 评价腔内修复术(endovascular aneurysm repair,EVAR)治疗肾下型腹主动脉瘤(abdominal aortic aneurysm,AAA)的围术期和中远期效果.方法 回顾性分析131例AAA行EVAR的临床资料,评价EVAR治疗AAA的安全性和中远期疗效.结果 手术时间(137±29) min,术中出血(142±20) ml、输血(46±26) ml、ICU恢复时间为(17±4)h.围术期主要并发症包括重度心功能不全8例、心肌梗死2例、肺部并发症5例,内漏4例等;随访中发现内漏15例,Ⅰ型8例,Ⅱ型5例,Ⅲ型和Ⅳ型各1例,死亡2例;Kaplan-Meier生存分析无并发症生存率及再次处理率提示60个月后仍有并发症发生,其中40％是需要再次处理的并发症.结论 EVAR是AAA的安全治疗方法,但需要长期严格随访并及时处理并发症.     

Comparison of mortality prediction models after open abdominal aortic aneurysm repair.

OBJECTIVES: Comparison of the accuracy of prediction of contemporary mortality prediction models after open Abdominal Aortic Aneurysm (AAA) surgery. METHODS: Post-operative data were collected from AAA patients from 2 UK Intensive Care Units (ICU). POSSUM and VBHOM based models were compared to the APACHE-AAA model which was able to adjust for the hospital-related effect on outcome. Model performance was assessed using measures of calibration, discrimination and subgroup analysis. RESULTS: 541 patients were studied. The in-hospital mortality rate for elective AAA repair (325 patients) was: 6.2% (95% confidence interval (c.i.) 3.5 to 8.8) and for emergency repair (216 patients) was: 28.7% (95% c.i. 22.5-34.9). The APACHE-based model had the best overall fit to the whole population of AAA patients, and also separately in elective and emergency patients. The V-POSSUM physiology-only (p<0.001) and VBHOM (p=0.011) models had a poor fit in elective patients. The RAAA-POSSUM physiology-only (p<0.001) and VBHOM models (p=0.010) had a poor fit in emergency patients. CONCLUSIONS: The APACHE-AAA model with its ability to adjust for both the hospital-related "effect" as well as the patient case-mix, was a more accurate risk stratification model than other contemporary models, in the post-operative AAA patient managed in ICU.     

Ruptured abdominal aortic aneurysm after endovascular repair

OBJECTIVE: The purpose of this study was to present the experience with aneurysm rupture after deployment of Guidant/EVT (Guidant) endografts and review previously reported cases with other devices. METHODS: Records from Guidant/EVT clinical trials and postmarket approval databases from February 1993 to August 2000 were analyzed to identify patients with rupture and to extract pertinent data. Previously reported cases were obtained with a Medline search. RESULTS: Seven ruptures were found with Guidant/EVT devices. Five of these occurred among the 686 patients in US Food and Drug Administration protocols (group I) who were followed for a mean of 41.8 +/- 21.9 months and limited to the subgroup of 93 first generation tube endografts. Two ruptures occurred in group II (3260 patients after market approval with limited follow-up), specifically in the subgroup of 166 patients who underwent treatment with second generation tube grafts. No ruptures were found in patients with bifurcation or unilateral iliac implants followed for a mean of 37.5 months. All ruptures were caused by distal aortic type I endoleaks on the basis of attachment system fractures (first generation devices only), aortic neck dilatations, persistent primary endoleaks, migration, overlooked imaging abnormalities, refused reintervention, and poor patient selection. The mortality rate was 57% (4/7) overall and was 50% for surgical repair (3/6). A literature search identified 40 additional ruptures related to other devices, for a total of 47. All 44 that were documented with adequate data were caused by endoleaks (26 type I, 2 type II, 11 type III, and 5 source not reported). Other contributing factors were graft module separation and graft wall deterioration. The overall mortality rate for the combined series was 50%, with an operative mortality rate of 41%. CONCLUSION: Postendograft AAA rupture is infrequent, although the true incidence rate is unclear because of inadequate follow-up of individual device designs. Tube endografts should be limited to the rare patient with ideal anatomy, no other alternatives, and at high risk for standard open repair. Prevention of aneurysm rupture requires long-term surveillance with attention to subtle imaging abnormalities and the establishment of reliable follow-up protocols for specific devices. The outcome of postendograft aneurysm rupture is similar to that of rupture without prior endograft therapy.     

Glomerular filtration rate is a predictor of mortality after endovascular abdominal aortic aneurysm repair

OBJECTIVE: Clinically evident renal disease is a risk factor for mortality after aneurysm repair. Serum creatinine is widely used as a measure of renal function in the preoperative evaluation of patients. Unfortunately, serum creatinine concentration is influenced by muscle mass, hydration status, and glomerular filtration rate (GFR). Calculated GFR, which takes predictors of muscle mass such as age, gender, and weight into account, is a more sensitive determinant of renal function than serum creatinine. We hypothesized that GFR would more accurately predict mortality after EVAR than serum creatinine. METHODS: We retrospectively evaluated our database of 398 patients who underwent EVAR with the AneuRx device between October 1999 and October 2004. There were 340 men and 58 women with a mean age of 73. GFR was calculated using the Cockcroft-Gault equation. The patients were divided into four quartiles by preoperative GFR: I (7 to 45), II (45 to 60), III (61 to 79), and IV (> or =80). Survival was estimated with the Kaplan-Meier method, and heterogeneity of mortality across strata was evaluated using the log-rank test. The GFR quartiles were compared with clinically accepted criteria for abnormal renal function (serum creatinine level > or =1.7). RESULTS: Actuarial survival at 48 months was 61.5%, 70.5%, 86.0%, and 85.7% for GFR quartiles I to IV, respectively (P < .003). Thirty-day mortality was 2.2% in quartile I, 3.2% in quartile II, and 0 in quartiles III and IV (P = .03 for q1 + q2 vs q3 + q4, P < .02 for q2 vs q3 + q4). Survival curves for quartiles II to IV were statistically indistinguishable, with quartile II running tangential to the two higher quartiles after the perioperative period. Quartile I fared significantly worse than the other three quartiles for the entire follow-up period (P < .005). According to American Kidney Foundation criteria (GFR <90), 83.3% of patients had abnormal renal function compared with 16.1% with abnormal serum creatinine (>1.7) (P < .0002). CONCLUSION: The risk of perioperative and long-term mortality in patients undergoing EVAR is more accurately stratified by using calculated GFR than serum creatinine alone. A GFR <45 is associated with decreased survival after EVAR. Perioperative mortality at a GFR of 45 to 60 is comparable with that of the lower quartile (GFR <45), but late survival is comparable with that of patients with GFR >60. The finding of increased risk of early mortality in patients in the 45 to 60 GFR range, with survivors enjoying good long-term outcome, suggests that these patients may most benefit from the use of alternative contrast agents and periprocedural renal protection techniques.     

Comparable perioperative mortality outcomes in younger patients undergoing elective open and endovascular abdominal aortic aneurysm repair

BackgroundEvidence for benefit of endovascular aneurysm repair (EVAR) over open surgical repair for de novo infrarenal abdominal aortic aneurysms (AAAs) in younger patients remains conflicting because of heterogeneous study populations and small sample sizes. The objective of this study was to compare perioperative and short-term outcomes for EVAR and open surgery in younger patients using a large national disease and procedure-specific data set.MethodsWe identified patients 65 years of age or younger undergoing first-time elective EVAR or open AAA repair from the Vascular Quality Initiative (2003-2014). We excluded patients with pararenal or thoracoabdominal aneurysms, those medically unfit for open repair, and those undergoing EVAR for isolated iliac aneurysms. Clinical and procedural characteristics were balanced using inverse propensity of treatment weighting. A supplemental analysis extended the study to those younger than 70 years.ResultsWe identified 2641 patients, 73% (n = 1928) EVAR and 27% (n = 713) open repair. The median age was 62 years (interquartile range, 59-64 years), and 13% were female. The median follow-up time was 401 days (interquartile range, 357-459 days). Unadjusted perioperative survival was 99.6% overall (open repair, 99.1%; EVAR, 99.8%; P < .001), with 97.4% 1-year survival overall (open repair, 97.3%; EVAR, 97.4%; P = .9). Unadjusted reintervention rates were five (open repair) and seven (EVAR) reinterventions per 100 person-years (P = .8). After propensity weighting, the absolute incidence of perioperative mortality was <1% in both groups (open repair, 0.9%, EVAR, 0.2%; P < .001), and complication rates were low. Propensity-weighted survival (hazard ratio, 0.88; 95% confidence interval, 0.56-1.38; P = .6) and reintervention rates (open repair, 6; EVAR, 8; reinterventions per 100 person-years; P = .8) did not differ between the two interventions. The analysis of those younger than 70 years showed similar results.ConclusionsIn this study of younger patients undergoing repair of infrarenal AAA, 30-day morbidity and mortality for both open surgery and EVAR are low, and the absolute mortality difference is small. The prior published perioperative mortality and 1-year survival benefit of EVAR over open AAA repair is not observed in younger patients. Further studies of long-term durability are needed to guide decision-making for open repair vs EVAR in this population.     

Computerised tomography after abdominal aortic aneurysm repair

CT scan early after AAA resection and graft implantation enables the detection of local complications such as extensive haematomas around the implanted graft (25 cases), gas bubbles (7 cases) fluid collections, inflammatory infiltration in the tissue around the graft and compression of organs in the neighbourhood (1 case) to be detected. The possibility of detecting these complications as early as possible allows effective treatment. The addition of CT guided needle biopsy to allow culture of suspicious material makes this a very useful technique. For these reasons routine postoperative CT scanning after aortic aneurysm surgery is recommended.     

Tetraplegia after elective abdominal aortic aneurysm repair

Spinal cord ischemia after elective infrarenal aortic aneurysm repair is extremely rare, and documented cases that are described are of paraplegia. This case of tetraplegia occurred in a 64-year-old man with disabling claudication after an aortobifemoral graft repair for occlusive disease associated with a 5-cm infrarenal aneurysm. Magnetic resonance imaging supported lower cervical spinal cord ischemia, an unusual area for ischemia during aortic clamping since this area is usually most resistant. Because the lower thoracic and upper lumbar region, typically T8, is more susceptible to ischemia due to the variable collateral spinal cord circulation, the level of clamping was unlikely to be responsible. Other causes are considered. It was likely to be multifactorial and illustrates the need for great attention to detail in perioperative management and patient consent.     

Pseudomembranous colitis after abdominal aortic aneurysm repair

We report three patients who developed pseudomembranous colitis following aortic aneurysm resection. Colonic ischaemia can occur after such surgery and ischaemic colonic mucosa is known to be more susceptible to damage by bacteria and their toxins. This colonic ischaemia together with the antibiotic prophylaxis used may render aortic aneurysm patients susceptible to pseudomembranous colitis. It is important to distinguish pseudomembranous from ischaemic colitis in these patients as specific and effective drug therapy can be given to those with the pseudomembranous type.