Thirty-day NSQIP database outcomes of open versus endoluminal repair of ruptured abdominal aortic aneurysms

The Impact of Perioperative Morbidities, Lack of Discharge Aspirin, and Lack of Discharge Statin on Long Term Survival Following EVAR

OBJECTIVE

Adverse perioperative events and discharge medications both have the potential to impact survival following endovascular abdominal aortic aneurysm repair (EVAR). We hypothesize that variables such as blood loss, reoperation in the same hospital admission, and lack of discharge statin/aspirin have significant effect on long term survival following EVAR. Similarly, other perioperative morbidities, are hypothesized to affect long term mortality. Quantifying the mortality effect of perioperative events and treatment emphasizes to physicians the critical nature of preoperative optimization, case planning, operative execution and postoperative patient management.

METHODS

All EVAR in the Vascular Quality Initiative between 2003 and 2021 were queried. Exclusions were: ruptured/symptomatic aneurysm; concomitant renal artery or supra-renal intervention at the time of EVAR; conversion to open aneurysm repair at the time of initial operation; and undocumented mortality status at the 5 year mark postoperatively. 18,710 patients met inclusion criteria. Multivariable Cox regression time dependent analysis was performed to investigate the strength of mortality association of the exposure variables. Standard demographic variables and pre-existing major co-morbidities were included in the regression analysis to account for disproportionate, deleterious co-variables amongst those experiencing the various morbidities. Kaplan-Meier survival analysis was performed to provide survival curves for the key variables.

RESULTS

Mean follow up was 5.99 years and 5-year survival for included patients was 69.2%. Cox regression revealed increased long term mortality to be associated with the following perioperative events: reoperation during the index hospital admission (HR 1.21, P = .034), perioperative leg ischemia (HR 1.34, P = .014), perioperative acute renal insufficiency (HR 1.24, P = .013), perioperative myocardial infarction (HR 1.87, P < .001), perioperative intestinal ischemia (HR 2.13, P < .001), perioperative respiratory failure (HR 2.15, P < .001), lack of discharge aspirin (HR 1.26, P < .001), and lack of discharge statin (HR 1.26, P < .001). The following pre-existing co-morbidities correlated with increased long term mortality (P < .001 for all) : body mass index under 20 kg/m2, hypertension, diabetes, coronary artery disease, reported history congestive heart failure, chronic obstructive pulmonary disease, peripheral artery disease, advancing age, baseline renal insufficiency and left ventricular ejection fraction less than 50%. Females were more likely to have EBL >300 mL, reoperation, perioperative MI, limb ischemia and acute renal insufficiency than males (P < .01 for all). Female sex trended but was not associated with increased long term mortality risk (HR 1.06, 95% CI .995-1.14, P = .072).

CONCLUSIONS

Survival after EVAR is improved with optimal operative planning to facilitate evading the need for reoperation and ensuring patients without contra-indication are discharged with aspirin and statin medications. Females and patients with pre-existing co-morbidity are at particularly higher risk for perioperative limb ischemia, renal insufficiency, intestinal ischemia and myocardial ischemia necessitating appropriate preparation and preventative measures.

The role of big data, risk prediction, simulation, and centralization for emergency vascular problems: Lessons learned and future directions

Vascular specialists remain in high demand in current practice and commonly oversee care delivery for a variety of clinical emergencies. Accordingly, the contemporary vascular surgeon must be facile with treating a spectrum of problems, including a complex, heterogeneous group of acute arteriovenous thromboembolic and bleeding diatheses. It has been documented previously that there are substantial current workforce limitations placing constraints on vascular surgical care provision. Moreover, with the aging at-risk population, there remains a considerable national urgency to improve timely diagnoses, specialty consultation, and appropriate transfer of patients to centers of excellence capable of providing a comprehensive compendium of emergency vascular services. Clinical decision aids, simulation training, and regionalization of nonelective vascular problems are all strategies that have been increasingly recognized to address these service gaps. Notably, clinical research in vascular surgery has traditionally focused on identification of patient- and procedure-related factors that influence outcomes by using resource-intensive causal inference methodology. By comparison, large data sets have only more recently been recognized to be a valuable tool that can provide heuristic algorithms to address more complex health care problems. Such data can be manipulated to generate clinical risk scores and decision aids, as well as robust outcome descriptions, which stand to inform stakeholders regarding best practice. The purpose of this review was to provide a robust overview of the lessons derived from the application of big data, risk prediction, and simulation in the management of vascular emergencies.

A New Predictive Model for In-Hospital Major Adverse Cardiac and Cerebrovascular Events in Chinese Patients After Major Noncardiac Surgery

Prediction tools focused on cardiovascular and cerebrovascular events after noncardiac surgery are lacking, particularly for Chinese patients. We developed and validated what we believe is a new predictive tool for postoperative major cardiovascular and cerebrovascular events (MACCEs) in Chinese patients in this study. Overall, 401 variables derived from 598 patients who received noncardiac surgery at our center were retrospectively analyzed to develop and validate the new predictive model for MACCEs during hospitalization. The 7 strongest predictors for MACCEs in the development cohort were chronic heart failure, age, atrial fibrillation, general anesthesia, history of coronary heart disease, high-risk procedures, and lymphocyte count. The area under the receiver operating characteristic curve was 0.698 (95% confidence interval 0.616 to 0.780) for the new predictive tool with the validation cohort. Receiver operating characteristic curve analysis showed the new predictive tool had better performance than the Revised Cardiac Risk Index and the American College of Surgeons National Surgical Quality Improvement Program scores. This new predictive tool is effective for the prediction of postoperative MACCEs in patients who undergo noncardiac surgery.

Impact of an emergency endovascular aneurysm repair protocol on 30-day ruptured abdominal aortic aneurysm mortality

OBJECTIVE

To characterize the longstanding impact of an emergency endovascular aneurysm repair (EVAR) protocol for ruptured abdominal aortic aneurysm (rAAA) on 30-day mortality.

METHODS

All adult patients with an rAAA who underwent a surgical or endovascular intervention at a tertiary care center between March 2001 and December 2018 were evaluated. An emergency EVAR protocol was introduced in January 2004. The primary outcome was 30-day mortality, which was calculated using risk-adjusted logistic regression for the preprotocol and postprotocol periods. A risk-adjusted cumulative sum analysis examined changes in 30-day mortality after protocol implementation.

RESULTS

We identified 376 patients with rAAA between 2001 and 2018 (75 preprotocol and 301 postprotocol), with a decreasing incidence of rAAA during the study period. The introduction of the protocol in 2004 was associated with increased EVAR use (63.6% vs 6.7%; P < .001). Patients managed according to the protocol were more frequently unstable (systolic blood pressure [SBP] of ≤80 mm Hg, 46.5% postprotocol vs 22.7% preprotocol; P < 0.001), with a lower average SBP (87.4 mm Hg postprotocol vs 106 mm Hg preprotocol; P < .001) and worse renal function (estimated glomerular filtration rate 61.5 mL/min postprotocol vs 83.2 mL/min preprotocol; P < .001). The risk-adjusted 30-day mortality was 23.2% with the emergency EVAR protocol, versus 35.8% preprotocol (P = .0727). A subgroup analysis demonstrated improved the 30-day mortality for unstable patients (SBP of ≤80 mm Hg) at 38.0% (vs 62.4% preprotocol introduction; P = .0190). A cumulative sum analysis demonstrated worse than expected mortality outcomes in the preprotocol period, and stability of surgical performance over 15 years after protocol introduction.

CONCLUSIONS

On reflection of a 17-year experience with EVAR for rAAA, the implementation of an emergency EVAR protocol demonstrated stable surgical performance for all patients with an rAAA and evidence of improved 30-day mortality for unstable patients with an rAAA. Since the protocol introduction, EVAR has become a mainstay intervention and, despite an increase in comorbid patients, the overall incidence of rAAA is declining. EVAR should be considered the first-line intervention for the appropriate patient unstable with an rAAA.

Migration of High Cardiac Risk Patients from Open to Endovascular Procedures is Evident within the Society for Vascular Surgery Vascular Quality Initiative

BACKGROUND

In this study, pre-operative medical complexity is estimated by the independently validated Vascular Quality Initiative VQI Cardiac Risk Index (CRI). This study aims to identify and correlate trends of CRI for open abdominal aortic aneurysm (OAR) with trends in the CRI for corresponding endovascular aortic repair (EVAR). This assessment of differences in estimated procedural risks will be used to support the theory that, patient migration is an important factor contributing to decreased POMI following open vascular procedures.

METHODS

A retrospective review of VQI data from 2003 to 2020 for all patients undergoing elective aortic repairs (OAR and EVAR) was conducted. The CRI scoring developed for the open repair (oCRI) was applied to both the OAR and EVAR cohorts, with variables specific to EVAR translated from similar open repair factors in the model where feasible. To evaluate for changes across time, patients were grouped into Eras based on year of procedure, subsequently, univariate analysis of post-operative myocardial infarction (POMI) rates and CRI scores were perfomed between each era.

RESULTS

A total of 56,067 elective aortic repairs were identified (83% EVAR, 17% OAR). Within the OAR cohort, the average oCRI estimate was 7.1% with significant decrease across the studied timeframe (8% ± 4.6%→6.9% ± 4.4%, P < 0.001), which corresponded to a significant decrease in observed clinical myocardial infarction (MI) rate (4.1%→1.4%, P < 0.001). Over that same time period, the open CRI was applied to the EVAR cohort, and the average oCRI estimate was 7.2% and showed a significant increase (6.6% ± 2.8%→7.2% ± 4.4%, P < 0.001). Within the EVAR cohort, the eCRI estimate did not show any significant changes over time (average 0.48%), while the actual rate of clinical MI showed a significant decrease (1.1%→0.3%, P = 0.002). Gap analysis was conducted within the EVAR cohort between CRI estimates of procedural risks from an open operation versus an EVAR, which demonstrated that patients within the EVAR cohort would, on an average, has had 6.7% higher risk of POMI had they undergone an open procedure.

CONCLUSIONS

Paradigm shifts with regard to patient selection for aortic repair is evident within this large national cohort. Over time, OAR patients had fewer preoperative estimated cardiac comorbidities and there is a corresponding decrease in POMI rates. As high-risk patients migrate from OAR to EVAR, there has been a subsequent increase in EVAR estimated pre-operative risks as the patients become more medically high-risk. Despite increasing complexity, rates of POMI in EVAR significantly decreased, potentially explained by improved operative technique and peri-operative care.

Characteristics and outcomes of small abdominal aortic aneurysm rupture in the American College of Surgeons National Surgical Quality Improvement Program database

OBJECTIVE

The current guidelines recommend elective abdominal aortic aneurysm (AAA) repair at 5.5 cm for men and 5.0 cm for women. However, rupture can occur in patients with an aneurysm smaller than these size thresholds. In the present study, we investigated the proportion of AAAs that rupture at sizes less than elective operative thresholds and compared the outcomes of repair with those of aneurysms that had ruptured at a larger size. Our hypothesis was that the rupture of small AAAs carries mortality similar to that of rupture at larger sizes.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program targeted vascular files for open AAA repair and endovascular aneurysm repair (EVAR) were reviewed for all cases of ruptured AAAs (rAAAs) from 2011 to 2018. The patients were divided into two groups: those with small AAAs that had ruptured at a size less than the current size guidelines for elective repair and those with large AAAs that had ruptured at a size that had met the criteria for elective repair. Univariate analyses were conducted to compare the comorbidities and perioperative outcomes of infrarenal rAAA repair between the groups. Multivariable logistic regression was performed to examine the differences in mortality between small and large rAAAs after controlling for confounding variables.

RESULTS

Of the 1612 rAAA repairs, 167 (10.4%) were small rAAAs. The proportion of small rAAAs did not significantly change during the study period (P = .15). The large rAAA group was more likely to have juxtarenal or suprarenal aneurysms compared with the small rAAA group (27% vs 16%; P = .001). A comparison of infrarenal rAAAs only demonstrated that the mean small rAAA (n = 141) diameter was 4.1 cm in the women and 4.5 cm in the men compared with the large rAAAs (n = 1051), with a mean diameter of 7.1 cm in women and 8.3 cm in men (P < .01 for the women; P < .01 for the men). The patients in the small rAAA group had had a significantly lower body mass index but were more likely to be African American and to have hypertension. The small rAAA group was more likely to present without hypotension and to have undergone EVAR. The repair of small rAAAs was associated with lower bleeding and mortality and a shorter mean operative time but with more readmissions. Multivariable regression analysis demonstrated that size was not associated with outcome after adjusting for other variables.

CONCLUSIONS

Of all AAA repairs classified as treating rupture, 10% were for patients with small AAAs. Patients with small rAAA were less likely to present with hypotension and were more likely to have undergone EVAR. Further research into sac morphology and more sensitive imaging modalities might help identify small rAAAs at high risk of rupture that would benefit from elective repair.

Describing Clinically Significant Arrhythmias in Postoperative Vascular Surgery Patients

BACKGROUND

The American Heart Association guidelines instruct use of postoperative telemetry (POT) should be reserved for patients undergoing cardiac procedures and/or those with ischemic cardiac symptoms, but acknowledge that major vascular procedures deserve unique consideration. Telemetry remains a limited resource in many hospitals; however, it has been poorly defined which vascular patients have greatest need for POT. The purpose of this study is to define the rates of postoperative arrhythmias (POAs) after major vascular operations using the Society for Vascular Surgery Vascular Quality Initiative (VQI) registry, identify independent predictors of POA, and determine the effect of POA on mortality to guide the use of POT in vascular patients.

METHODS

A retrospective cohort study was performed using the following VQI modules: open abdominal aortic aneurysm repair (oAAA), complex endovascular aneurysm repair (EVAR) (thoracic endovascular aortic repair [TEVAR]/c-EVAR), EVAR, suprainguinal bypass (SIB), and infrainguinal bypass (IIB). POA was defined in the VQI as a new rhythm disturbance requiring treatment with medication or cardioversion. The incidence of POA, preoperative risk factors, and demographics were determined for each procedure.

RESULTS

A total of 121,652 procedures were identified with an overall POA event rate of 5.1% (n = 6,265). Procedure-specific event rates for POA among VQI registries are as follows: oAAA 14.4%, TEVAR/c-EVAR 8.5%, EVAR 2.7%, SIB 6.2%, and IIB 3.8%. Across all procedure types, POA was associated with emergent operations and increased procedure time. Procedure-specific multivariable regression revealed additional independent preoperative intraoperative factors associated with POA that were unique with each procedure. Across all procedural groups, the presence of POA was associated with increased rates of clinical myocardial infarction and decreased survival on Kaplan-Meier analysis.

CONCLUSIONS

Rates of POA in patients undergoing vascular procedures appear higher than previously reported, and POA is associated with decreased survival. Our study elucidated patient- and procedure-specific predictor factors associated with POA that can be used to inform the use of POT.

Long-Term Trends in Preoperative Cardiac Evaluation and Myocardial Infarction after Elective Vascular Procedures

BACKGROUND

Vascular surgery has seen rapid increase in the use of less invasive endovascular therapies along with advancements in cardiac perioperative optimization in the past 2 decades. However, a recent American College of Surgeons National Surgical Quality Improvement Program database study found no improvement in postoperative myocardial infarction (POMI) over a 10-year period in high-risk procedures. The national Society for Vascular Surgery Vascular Quality Initiative (VQI) registry provides a more in-depth characterization of vascular surgery procedures. Here, we sought to evaluate long-term trends in POMI using VQI registry data for patients undergoing carotid endarterectomy (CEA), thoracic endovascular aortic repair (TEVAR), endovascular aortic repair (EVAR), open abdominal aortic aneurysm repair (oAAA), suprainguinal bypass (SIB), and infrainguinal bypass (IIB).

METHODS

A retrospective cohort study was performed using data on elective procedures from 2003 to 2017. Procedures were subdivided by date of operation into 3-year era consecutive groups for subanalysis (2003-05, 2006-08, 2009-11, 2012-14, and 2015-17). The incidence of POMI, preoperative risk factors (including individual patient VQI cardiac risk index (CRI)), and demographics were determined over time.

RESULTS

A total of 227,837 elective procedures were identified: CEA (n = 88,805, 39.0%), TEVAR (n = 7,494, 3.3%), EVAR (n = 34,376, 15.1%), oAAA (n = 7,568, 3.3%), SIB (n = 11,354, 5.0%), and IIB (n = 34,661, 15.2%). Across all procedures, the overall rate of POMI was 1.3%. POMI rates from 2003-05 to 2015-17 for CEA decreased from 0.9% to 0.7% (P = 0.21), EVAR from 2.0% to 0.7%, P = 0.003, oAAA from 6.8% to 5.1% (P = 0.12), and IIB from 3.8% to 2.4% (P = 0.003). SIB POMI decreased from 3.06% to 2.95%, P = 0.85 from 2009 to 17. While POMI after TEVAR increased from 2.40% to 2.56% from 2009 to 17, P = 0.91. Over these same time periods, only EVAR and IIB had a reduction in CRIs (P = 0.059 and P < 0.001, respectively). CEA, EVAR, IIB, and oAAA all showed a significant (P < 0.001) increase in preoperative statin use.

CONCLUSIONS

Except for TEVAR, the incidence of POMI has remained unchanged or decreased over the past 15 years in VQI registries. Patients undergoing IIB and EVAR demonstrated decreases in POMI rates that correspond with a reduction in CRIs and increased preoperative statin use. CEA and SIB had no significant change in POMI rates nor CRIs. The etiology of decreased POMI rate is uncertain, but increasing statin use, patient-specific factors, and patient selection for procedures may be important drivers of this improvement.

Morphologic and Operative Evolution of Open Ruptured Abdominal Aortic Aneurysm Repair

BACKGROUND

Increased use of endovascular repair for intact abdominal aortic aneurysms has fundamentally shifted the approach to ruptured aneurysms. Unfortunately, not all patients are anatomically suited for endovascular repair. It is hypothesized that, in the endovascular era, patients undergoing open repair are increasingly complex; with an unknown impact on postoperative morbidity and mortality.

MATERIAL AND METHODS

The Cleveland Clinic Foundation database was queried for all patients undergoing open repair of ruptured abdominal aortic aneurysms (rAAA) from 2006 to 2015. Electronic medical charts and cross-sectional imaging were retrospectively reviewed. The overall patient cohort was dichotomized between early (E-OR, 2006 to 2010) and late open repairs (L-OR, 2011 to 2015). Groups were compared based on demographic, anatomic, and perioperative variables. The primary endpoint was perioperative mortality. Secondary endpoints included overall mortality, late aneurysm-related mortality, and perioperative morbidity.

RESULTS

Of 140 patients who underwent open repair of rAAA (63, E-OR; 77, L-OR), 76% had cross-sectional imaging available for review. Aneurysm repairs in the later time period had significantly shorter infrarenal neck lengths, were more likely to have a prior aortic intervention, tended to have poor access vessels, and were more likely to require visceral or renal revascularization (each P < 0.05). While late survival did not differ between time periods, perioperative mortality (27 vs. 46%, P = 0.021) and late aneurysm-related mortality (29.9% vs. 47.6%, P = 0.031) was lower for L-OR compared with E-OR. While no anatomic variables significantly impacted survival, early time period of repair, presence of chronic kidney disease, and need for cardiopulmonary resuscitation were predictive of both perioperative and overall mortality on univariate and multivariate analysis.

CONCLUSIONS

Despite the increasing anatomic and operative complexity of patients undergoing open repair of rAAAs, perioperative mortality and late aneurysm-related mortality have improved over time. These results highlight the need for both systems and expertise needed to appropriately treat this changing patient population.

Optimizing Preoperative Anemia to Improve Patient Outcomes

Anemia is a decrease in red blood cell mass, which hinders oxygen delivery to tissues. Preoperative anemia has been shown to be associated with mortality and morbidity following major surgery. The preoperative care clinic is an ideal place to start screening for anemia and discussing potential interventions in order to optimize patients for surgery. This article (1) reviews the relevant literature and highlights consequences of preoperative anemia in the surgical setting, and (2) suggests strategies for screening and optimizing anemia in the preoperative setting.

Abdominal Aortic Aneurysm: Evolving Controversies and Uncertainties

Abdominal aortic aneurysm (AAA) is defined as a permanent dilatation of the abdominal aorta that exceeds 3 cm. Most AAAs arise in the portion of abdominal aorta distal to the renal arteries and are defined as infrarenal. Most AAAs are totally asymptomatic until catastrophic rupture. The strongest predictor of AAA rupture is the diameter. Surgery is indicated to prevent rupture when the risk of rupture exceeds the risk of surgery. In this review, we aim to analyze this disease comprehensively, starting from an epidemiological perspective, exploring etiology and pathophysiology, and concluding with surgical controversies. We will pursue these goals by addressing eight specific questions regarding AAA: (1) Is the incidence of AAA increasing? (2) Are ultrasound screening programs for AAA effective? (3) What causes AAA: Genes versus environment? (4) Animal models: Are they really relevant? (5) What pathophysiology leads to AAA? (6) Indications for AAA surgery: Are surgeons over-eager to operate? (7) Elective AAA repair: Open or endovascular? (8) Emergency AAA repair: Open or endovascular?

Epidemiology and contemporary management of abdominal aortic aneurysms

Abdominal aortic aneurysm (AAA) is most commonly defined as a maximal diameter of the abdominal aorta in excess of 3 cm in either anterior-posterior or transverse planes or, alternatively, as a focal dilation ≥ 1.5 times the diameter of the normal adjacent arterial segment. Risk factors for the development of AAA include age > 60, tobacco use, male gender, Caucasian race, and family history of AAA. Aneurysm growth and rupture risk appear to be associated with persistent tobacco use, female gender, and chronic pulmonary disease. The majority of AAAs are asymptomatic and detected incidentally on various imaging studies, including abdominal ultrasound, and computed tomographic angiography. Symptoms associated with AAA may include abdominal or back pain, thromboembolization, atheroembolization, aortic rupture, or development of an arteriovenous or aortoenteric fistula. The Screening Abdominal Aortic Aneurysms Efficiently (SAAAVE) Act provides coverage for a one-time screening abdominal ultrasound at age 65 for men who have smoked at least 100 cigarettes and women who have family history of AAA disease. Medical management is recommended for asymptomatic patients with AAAs < 5 cm in diameter and focuses on modifiable risk factors, including smoking cessation and blood pressure control. Primary indications for intervention in patients with AAA include development of symptoms, rupture, rapid aneurysm growth (> 5 mm/6 months), or presence of a fusiform aneurysm with maximum diameter of 5.5 cm or greater. Intervention for AAA includes conventional open surgical repair and endovascular aortic stent graft repair.

A preoperative risk score for transfusion in infrarenal endovascular aneurysm repair to avoid type and cross

OBJECTIVE

Preoperative type and cross are often routinely ordered before elective endovascular aneurysm repair (EVAR), but the cost of this practice is high, and transfusion is rare. We therefore aimed to stratify patients by their risk of transfusion to identify a cohort in whom a type and screen would be sufficient.

METHODS

We queried the targeted vascular module of the National Surgical Quality Improvement Program (NSQIP) for all elective EVARs from 2011 to 2015. We included only infrarenal aneurysms and excluded ruptured aneurysms and patients transfused within 72 hours preoperatively. Two-thirds of the cases were randomly assigned to a model derivation cohort and one third to a validation cohort. We created and subsequently validated a risk model for transfusion within the first 24 hours of surgery (including intraoperatively), using logistic regression.

RESULTS

Between 2011 and 2015, there were 4875 patients who underwent elective infrarenal EVAR, only 221 (4.5%) of whom received a transfusion within 24 hours of surgery. The frequency of transfusion during the study period declined monotonously from 6.5% in 2011 to 3.2% in 2015. The factors independently associated with transfusion were preoperative hematocrit <36% (odds ratio [OR], 3.4 [95% confidence interval, 2.1-5.4]; P < .001), aortic diameter (per centimeter increase: OR, 1.2 [1.03-1.4]; P = .02), preoperative dependent functional status (OR, 2.5 [1.1-5.5]; P = .03), and chronic obstructive pulmonary disease (OR, 1.7 [1.04-2.9]; P = .04). A risk prediction model based on these criteria produced a C statistic of 0.69 in the prediction cohort and 0.76 in the validation cohort and a Hosmer-Lemeshow goodness of fit of 0.62 and 0.14, respectively. A score of <3 of 9, corresponding to a <5% probability of transfusion, would avoid preoperative type and cross in 86% of patients. Of the 4203 patients (86%) with a hematocrit >36%, only 6 (0.1%) had a risk score of >3.

CONCLUSIONS

Perioperative transfusion for EVAR is becoming increasingly uncommon and is predicted well by a transfusion risk score or simply a hematocrit of <36%. Application of this risk score would avoid unnecessary type and cross in the majority of patients, leading to significant savings in both time and cost.

Open versus endovascular repair of ruptured abdominal aortic aneurysms: What have we learned after more than 2 decades of ruptured endovascular aneurysm repair?

BACKGROUND

Ruptured abdominal aortic aneurysm is one of the most difficult clinical problems in surgical practice, with extraordinarily high morbidity and mortality. During the past 23 years, the literature has become replete with reports regarding ruptured endovascular aneurysm repair.

METHODS

A variety of study designs and databases have been utilized to compare ruptured endovascular aneurysm repair and open surgical repair for ruptured abdominal aortic aneurysm and studies of various designs from different databases have yielded vastly different conclusions. It therefore remains controversial whether ruptured endovascular aneurysm repair improves outcomes after ruptured abdominal aortic aneurysm in comparison to open surgical repair.

RESULTS

The purpose of this article is to review the best available evidence comparing ruptured endovascular aneurysm repair and open surgical repair of ruptured abdominal aortic aneurysm, including single institution and multi-institutional retrospective observational studies, large national population-based studies, large national registries of prospectively collected data, and randomized controlled clinical trials.

CONCLUSION

This article will analyze the study designs and databases utilized with their attendant strengths and weaknesses to understand the sometimes vastly different conclusions the studies have reached. This article will attempt to integrate the data to distill some of the lessons that have been learned regarding ruptured endovascular aneurysm repair and identify ongoing needs in this field.

Outcomes of endovascular and open surgical repair of ruptured abdominal aortic aneurysms in elderly patients

BACKGROUND

Endovascular aneurysm repair (EVAR) is becoming the preferred treatment modality for patients with a ruptured abdominal aortic aneurysm (rAAA). Although the survival advantage of EVAR over open aortic repair (OAR) has been shown in some studies, it is unclear whether this benefit extends to elderly patients. We sought to evaluate the outcomes of rAAA repair in octogenarians.

METHODS

We reviewed the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) data set (2005-2014) to identify patients older than 80 years who were treated with EVAR and OAR for rAAA. Procedural trends were evaluated during the course of the study period. Perioperative outcomes including mortality, morbidity, and hospital length of stay (LOS) were compared. Multivariable regression models were used to identify predictors of perioperative mortality and morbidity.

RESULTS

Among 1048 elderly patients who underwent rAAA repair, 450 (43%) and 598 (57%) were treated with EVAR and OAR, respectively. The use of EVAR to treat rAAA had increased significantly in this population of patients (0% in 2005 vs 56% in 2014; P < .001). The overall 30-day mortality rate among octogenarians was 41%. The mortality rate was significantly higher among those treated with OAR compared with EVAR (47% vs 33%; P < .001). Pneumonia (21% vs 10%; P < .001), reintubation (14% vs 9%; P < .001), and >48-hour ventilator dependence (43% vs 21%; P < .001) were significantly higher in patients undergoing OAR. Hospital LOS (13 vs 10 days; P < .001) was also longer in the OAR cohort. Compared with EVAR, OAR was independently predictive of 30-day mortality (adjusted odds ratio [AOR], 1.7; 95% confidence interval [CI], 1.3-2.2; P < .001), pneumonia (AOR, 2.4; 95% CI, 1.7-3.6; P < .001), >48-hour ventilator dependence (AOR, 2.5; 95% CI, 1.8-3.3; P < .001), and longer LOS (adjusted mean ratio, 1.4; 95% CI, 1.2-1.6; P < .001).

CONCLUSIONS

Elderly patients have significant but acceptable perioperative mortality and morbidity after rAAA repair. Use of endovascular repair in the elderly population has increased and is associated with better perioperative survival and 30-day outcomes compared with traditional open repair in this study.

Outcomes After Use of Aortouniiliac Endoprosthesis Versus Modular or Unibody Bifurcated Endoprostheses for Endovascular Repair of Ruptured Abdominal Aortic Aneurysms

OBJECTIVES

Outcomes after endovascular repair (EVAR) of ruptured abdominal aortic aneurysms (rAAAs) have been widely published. There is, however, controversy on the role of the use of aortouniiliac endoprosthesis (AUI) versus modular or unibody bifurcated endoprosthesis (MUB) for repair of rAAAs. We study and compare 30-day outcomes after use of AUI and MUB for all rAAAs focusing specifically on patients with instability.

MATERIALS AND METHODS

Patients who underwent EVAR for rAAA (n = 425) using AUI (n = 55; 12.9%) and MUB (n = 370; 87.1%) were identified from the American College of Surgeons' National Surgical Quality Improvement Program (2005-2010) database. Univariable and multivariable logistic regression analyses were performed.

RESULTS

No significant difference ( P > .5) was seen in comorbidities between patients who underwent EVAR with AUI or MUB; there was also no change in endoprosthesis use from 2005 to 2010 ( P = .7). Patients who underwent EVAR with AUI more commonly had a history of peripheral arterial procedure (10.9% vs 4.6%; P = .053) and preoperative transfusion of >4 U packed red blood cells (18.2% vs 6.8%; P = .004). Use of AUI versus MUB was associated with more 30-day wound complications (16.4% vs 6.2%; P = .01), return to operating room (38.2% vs 20.0%; P = .003), and mortality (34.5% vs 21.4%; P = .03). On multivariable analysis, use of AUI was associated with an increased risk of 30-day mortality (odds ratio: 2.4; 95% confidence interval: 1.1-5.3). On subanalysis of the cohort for only the patients with unstable rAAA (n = 159; AUI = 29 and MUB = 130), 30-day mortality for AUI versus MUB was still higher but not statistically significant (44.8% vs 32.3%; P = .2).

CONCLUSION

Endovascular repair for ruptured AAA using aortouniliac endoprosthesis is associated with higher 30-day mortality than using modular or unibody bifurcated endoprosthesis.

Massive Blood Transfusion in Patients with Ruptured Abdominal Aortic Aneurysm

OBJECTIVES

The aim was to study blood transfusions and blood product ratios in massively transfused patients treated for ruptured abdominal aortic aneurysms (rAAAs).

METHODS

This was a registry based cohort study of rAAA patients repaired at three major vascular centres between 2008 and 2013. Data were collected from the Swedish Vascular Registry, hospitals medical records, and local transfusion registries. The transfusion data were analysed for the first 24 h of treatment. Massive transfusion (MT) was defined as 4 or more units of red blood cell (RBC) transfused within 1 h, or 10 or more RBC units within 24 h. Logistic regression was used to calculate the odds ratio of 30 day mortality associated with the ratios of blood products and timing of first units of platelets (PLTs) and fresh frozen plasma (FFP) transfused.

RESULTS

Three hundred sixty nine rAAA patients were included: 80% men; 173 endovascular aneurysm repairs (EVARs) and 196 open repairs (ORs) with median RBC transfusion 8 units (Q1-Q3, 4-14) and 14 units (Q1-Q3, 8-28), respectively. A total of 261 (71%) patients required MT. EVAR patients with MT (n = 96) required less transfusion than OR patients (n = 165): median RBC 10 units (Q1-Q3, 6-16.5) vs. 15 units (Q1-Q3, 9-26) (p = .002), FFP 6 units (Q1-Q3, 2-14.5) vs. 13 units (Q1-Q3, 7-24) (p < .001), and PLT 0 units (Q1-Q3, 0-2) vs. 2 units (Q1-Q3, 0-4) (p = .01). Median blood product ratios in MT patients were FFP/RBC (EVAR group 0.59 [0.33-0.86], OR group 0.84 [0.67-1.2]; p < .001], and PLT/RBC (EVAR 0 [0-0.17], OR 0.12 (0-0.18); p < .001]. In patients repaired by OR a FFP/RBC ratio close to 1 was associated with reduced 30 day mortality (p = .003). The median PLT/RBC ratio was higher during the later part of the study period (p < .001, median test), whereas there was no significant difference in median FFP/RBC ratio (p = .101, median test).

CONCLUSION

The majority of rAAA patients undergoing EVAR required MT. EVAR patients treated with MT had lower FFP/RBC and PLT/RBC ratios than OR patients with MT. The mortality risk was lower with FFP/RBC ratio close to 1:1 in open repaired patients requiring MT. The 24 h PLT/RBC ratio increased over the study period.

Endovascular Repair of a Ruptured Pararenal Aortic Aneurysm Using the Nellix Endovascular Aneurysm Sealing System and Chimney Grafts

Purpose: To demonstrate the feasibility of emergent endovascular repair of a ruptured pararenal aneurysm using chimney grafts and the Nellix endovascular aneurysm sealing (EVAS) system to reduce the potential for endoleak from the gutters around the chimney grafts. Case Report: A 74-year-old patient presented with a ruptured pararenal aneurysm. Because of anatomical considerations after previous aortic surgery, conventional endovascular aneurysm repair was deemed impossible. It was decided to exclude the aneurysm with a Nellix EVAS system in conjunction with two chimneys to the renal arteries, even though this was outside the instructions for use of the device. Active bleeding was stopped directly after positioning the chimneys and filling the endobags with polymer. Completion angiography showed aneurysm exclusion and patent renal arteries. Renal function remained stable, and the patient was discharged at the third postoperative day. At 6 months, duplex ultrasound and computed tomography showed patent stents and chimneys and no evidence of endoleak. Conclusion: Using chimney grafts in combination with the Nellix endoprosthesis in a ruptured pararenal aneurysm is feasible. However, more robust data on both chimney-EVAS and EVAS in ruptured cases are required.

Long-term survival and quality of life after open abdominal aortic aneurysm repair

BACKGROUND

Open repair of abdominal aortic aneurysm (AAA) generally involves postsurgery admission to the intensive care unit (ICU). Few studies have evaluated the impact of surgery for either ruptured or nonruptured AAA (with postoperative ICU treatment) on long-term survival and quality of life. The primary aim of this study was to quantify long-term survival and health-related quality of life (HrQpL) of a cohort of patients undergoing open AAA repair after hospital discharge.

METHODS

Consecutive patients undergoing open elective or acute AAA reconstruction with postoperative admission to the ICU and discharged alive from the hospital during 2009 were identified. Primary outcome measures were 1-year and long-term mortality. The secondary outcome was the HrQoL using the EuroQol-6D (EQ-6D) questionnaire at the end of the follow-up period.

RESULTS

A total of 263 patients were treated and postoperatively discharged alive: 56 had a ruptured AAA (rAAA), 35 a symptomatic AAA, and 172 an asymptomatic AAA. The 1-year mortality after open AAA repair was 8 %. Overall, 39 % of patients died within 10 postoperative years (mean 6.0 ± 2.8 years). Long-term survival of patients with a ruptured or symptomatic aneurysm was similar to that of patients undergoing elective aneurysm repair. Long-term HrQoL of the total study population was worse than that of an age-matched general Dutch population on the EQ-us (range 0-1, difference 0.12). This decrease in HrQoL was mainly seen in mobility, self-care, usual activities, and cognition.

CONCLUSIONS

Ten years after open AAA repair, the overall survival rate was 59 %. Long-term survival and HrQoL were similar for patients with a repaired ruptured or symptomatic aneurysm and those who underwent elective aneurysm repair. There were also no differences in patients with infrarenal versus juxtarenal/suprarenal aneurysms. Surviving patients had a lower HrQoL than the age-matched general Dutch population, especially regarding mobility, self-care, usual activities, and cognition.

Abdominal compartment syndrome associated with endovascular and open repair of ruptured abdominal aortic aneurysms

BACKGROUND

Abdominal compartment syndrome (ACS) is a known complication of ruptured abdominal aortic aneurysm (rAAA) repair and can occur with either endovascular (EVAR) or open repair. We hypothesize that the underlying mechanism for the development of ACS may differ for patients treated with EVAR or open operation.

METHODS

All patients who presented with rAAA at a tertiary care medical center between January 2005 and December 2010 were included in the study. Demographic factors, type of repair (open vs EVAR), development of ACS, intraoperative and postoperative fluid requirements, estimated blood loss, length of stay, and morbidity and mortality were recorded. Student t-test and Fisher exact test were performed. A P value < .05 was considered significant.

RESULTS

Seventy-three patients, 62 men and 11 women with an average age of 70.5 years, were treated for rAAA. Forty-four (60%) underwent open repair; 29 (40%) had EVAR. Overall mortality was 42% (31 of 73), with mortality being 31% (9 of 29) in EVAR and 48% (21 of 44) in open repair. ACS developed in 21 patients (29%), more frequently in open repair than in EVAR (15 of 44 [34%] vs 6 of 29 [21%]; P = NS). Mortality was higher in patients who developed ACS compared with those without ACS (13 of 21 [62%] vs 17 of 52 [33%]; P = .022). This finding was especially pronounced in the EVAR group, in which mortality in patients with ACS was 83% (5 of 6) compared with 17% (4 of 23) without ACS (P = .005). Intraoperative fluid requirements were significantly higher in EVAR patients who developed ACS compared with those without ACS, including packed red blood cells (5600 mL vs 1100 mL; P < .0001), total blood products (9300 mL vs 1500 mL; P < .001), crystalloid (11,200 mL vs 4500 mL; P < .001), and estimated blood loss (5000 mL vs 660 mL; P = .006). In patients treated with open repair, there were no significant differences in intraoperative fluid requirements between those who developed ACS and those without ACS. However, patients who developed ACS after open repair required significantly more crystalloid on the first and second postoperative days (first postoperative day, 8300 mL vs 5600 mL [P = .01]; second postoperative day, 6500 mL vs 3800 mL [P = .004]).

CONCLUSIONS

This study demonstrates that the development of ACS after repair of rAAA is associated with increased mortality, especially in EVAR-treated patients. The higher intraoperative blood and blood product requirements associated with ACS in EVAR patients suggest that one potential cause of early ACS is continued hemorrhage from lumbar and inferior mesenteric vessels through the ruptured aneurysm sac. Hence, open ligation of such vessels should be considered in patients developing early ACS after EVAR for rAAA.

Emergent endovascular vs. open surgery repair for ruptured abdominal aortic aneurysms: a meta-analysis

Objectives

To systematically review studies comparing peri-operative mortality and length of hospital stay in patients with ruptured abdominal aortic aneurysms (rAAAs) who underwent endovascular aneurysm repair (EVAR) to patients who underwent open surgical repair (OSR).

Methods

The Medline, Cochrane, EMBASE, and Google Scholar databases were searched until Apr 30, 2013 using keywords such as abdominal aortic aneurysm, emergent, emergency, rupture, leaking, acute, endovascular, stent, graft, and endoscopic. The primary outcome was peri-operative mortality and the secondary outcome was length of hospital stay.

Results

A total of 18 studies (2 randomized controlled trials, 5 prospective studies, and 11 retrospective studies) with a total of 135,734 rAAA patients were included. rAAA patients who underwent EVAR had significantly lower peri-operative mortality compared to those who underwent OSR (overall OR = 0.62, 95% CI = 0.58 to 0.67, P<0.001). rAAA patients with EVAR also had a significantly shorter mean length of hospital stay compared to those with OSR (difference in mean length of stay ranged from −2.00 to −19.10 days, with the overall estimate being −5.25 days (95% CI = −9.23 to −1.26, P = 0.010). There was no publication bias and sensitivity analysis showed good reliability.

Conclusions

EVAR confers significant benefits in terms of peri-operative mortality and length of hospital stay. There is a need for more randomized controlled trials to compare outcomes of EVAR and OSR for rAAA.

Risk factors affecting survival after surgical repair of ruptured abdominal aortic aneurysm

PURPOSE

The purpose of this study is to identify the risk factors affecting the high mortality rates associated with the treatment of ruptured abdominal aortic aneurysm (AAA).

METHODS

In this retrospective study, the subjects consisted of 105 patients who underwent repair of ruptured AAA at our institution from December 1984 to March 2012. We compared the patients of ruptured AAA in survival group with those in death group to evaluate the clinical factors in ruptured AAA mortality.

RESULTS

The operative and in-hospital mortality of ruptured AAA patients was 22.9% compared with 1.9% for that of non-ruptured AAA patients. The mean hemoglobin level was significantly lower in death group than in survival group. Intraoperative bleeding volume was significantly higher in death group than in survival group. Cox proportional hazard analysis showed that level 3 or 4 according to the Rutherford classification, preoperative hemoglobin level of less than 9.0 g/dl, intraoperative blood loss volume of more than 3000 ml, postoperative bowel ischemia and class 3 or 4 according to the Fitzgerald classification were significantly associated with high mortality.

CONCLUSION

These findings showed that every effort to maintain preoperative hemodynamic stability reduce volumes of blood loss in operation, and to minimize postoperative deterioration of organ functions would be essential to improve patient survival.

Perioperative haemorrhage in endovascular abdominal aneurysm repair affects outcome

OBJECTIVE

This study aimed to evaluate the outcome and predisposing factors related to perioperative bleeding in patients treated with endovascular aneurysm repair (EVAR) for ruptured and non-ruptured abdominal aortic aneurysm (AAA).

DESIGN

This was a retrospective cohort study.

METHODS

A total of 525 consecutive patients (73% elective) with AAA underwent EVAR at two vascular centres from 2008 to 2011. From registry data perioperative bleeding was analysed in relation to outcome and preoperative data.

RESULTS

A total of 453 (86%) patients presented with a perioperative bleeding <1000 ml, 42 (8%) patients 1000-1999 ml, 19 (4%) patients 2000-5000 ml and 11 (2%) >5000 ml. Other than ruptured AAA (n = 90), no preoperative risk factors for increased perioperative bleeding were found. Open femoral artery access (n = 101), branched (n = 18) and uni-iliacal endografts (n = 18) and introducer size were associated with increased perioperative bleeding (P < 0.001). In multivariable logistic regression only rupture and perioperative bleeding >2000 ml were significantly related to 30-day mortality (odds ratio 10.6 (range 3.8-29.6) and 13.4 (range 4.8-37.4), respectively). Postoperative renal failure, multi-organ failure, >5 days at intensive care unit, bowel ischaemia and abdominal compartments syndrome were significantly related to perioperative bleeding >2000 ml (P < 0.001).

CONCLUSION

Large perioperative bleeding during EVAR is a clinical problem that affects outcome. About 10% of elective AAA patients and 34% of patients with ruptured AAA, undergoing EVAR, present a perioperative blood loss exceeding 1 l. In our study, a perioperative blood loss exceeding 2 l was independently associated with increased mortality and morbidity in both acute and elective AAA patients. Open femoral access, branched EVAR and larger diameter introducers were associated with increased perioperative blood loss. ETHICAL APPLICATION: 2011/664-31/3 (approved).

Safety of surgical resident training

The current structure of residency training allows for safe participation of residents in the care of surgical patients. In part, this is likely due to the ability of attending-level surgeons and educators to adequately select and provide the supervision needed for different levels of residents. Nonetheless, efforts have to be made to ensure the optimal safety of patients in several settings of modern health care. For laparoscopic surgery, training and simulation are highly advisable in preparing residents to perform well in the early stage of their learning curves. Attention has to be given to safe and complete hand-offs, especially with the increased focus on restricting work hours and the increased number of changing shifts. Measures to ensure optimal preparation of surgical residents to perform well in stressful situations should also be taken, because such situations are an intrinsic part of this specialty. It is only by focusing on all these aspects that we can ensure the safety for our patients and provide the best possible training for the next generation of surgeons.

Predictors of postoperative mortality of ruptured abdominal aortic aneurysm: a retrospective clinical study

PURPOSE

Despite significant improvements in surgery, anesthesia, and postoperative critical care, the postoperative mortality rate of ruptured abdominal aortic aneurysm (RAAA) has remained at 40% to 50% for several decades. Therefore, we evaluated factors associated with the postoperative mortality of RAAA.

MATERIALS AND METHODS

From January 1999 to December 2008, a retrospective study was performed with 34 patients who underwent open repair of RAAA. The preoperative factors included age, sex, smoking, comorbidities, serum creatinine, hemoglobin, shock, pulse rate, and time from emergency room to operation room. The intraoperative factors included blood loss, transfusion, aortic clamping site and time, aneurysmal characteristics, rupture type, graft type, hourly urine output (HUO), and operative time. The postoperative factors included inotropic support, renal replacement therapy (RRT), reoperation, bowel ischemia, multiple organ failure (MOF), and intensive care unit stay. The 2-day and the 30-day mortality rates were analyzed separately.

RESULTS

The 2-day and the 30-day mortality rates were 14.7% and 41.2%, respectively. On univariate analysis, shock, transfusion, HUO, inotropic support and MOF for the 2-day mortality and serum creatinine, transfusion, aortic clamping site, HUO, inotropic support, RRT and MOF for the 30-day mortality were statistically significant. On multivariate analysis, shock, inotropic support and MOF for the 2-day mortality and aortic clamping site, RRT and MOF for the 30-day mortality were statistically significant.

CONCLUSION

To decrease the postoperative mortality rate of RAAA, prevention of massive hemorrhage and acute renal failure with infrarenal aortic clamping, as well as prompt operative control of bleeding and maintenance of systemic perfusion are important.

Endovascular repair of ruptured abdominal aortic aneurysm does not confer survival benefits over open repair

OBJECTIVE

Endovascular repair of ruptured abdominal aortic aneurysm (rAAA) is being increasingly performed despite lack of good evidence for its superiority. Other reported studies suffer from patient selection and publication bias with limited follow-up. This study is a single-center propensity score comparing early and midterm outcomes between open surgical repair (OSR) and endovascular repair of rAAA (REVAR).

METHODS

A retrospective review from January 2001 to November 2010 identified 312 patients who underwent rAAA repairs. Thirty-one patients with antecedent AAA repair and three with incomplete records were excluded, leaving 37 REVARs and 241 OSRs. Propensity score-based matching for sex, age, preoperative hemodynamic status, surgeon's annual AAA volume, and preoperative cardiopulmonary resuscitation was performed in a 1:3 ratio to compare outcomes. Thirty-seven REVARs were matched with 111 OSRs. Late survival was estimated by Kaplan-Meier methods.

RESULTS

Operative time and blood replacement were higher with OSR. Overall complication rates were similar (54% REVAR vs 66% OSR; P = .23), except for higher incidences of tracheostomies (21% vs 3%; P = .015), myocardial infarction (38% vs 18%; P = .036), and acute tubular necrosis (47% vs 21%; P = .009) with OSR. Operative mortality rates were similar (22% REVAR vs 32% OSR), with an odds ratio of 0.63 for REVAR (95% confidence interval = [0.24, 1.48]; P = .40). No differences in the incidences for secondary interventions for aneurysm- or graft-related complications were noted (22% REVAR vs 22% OSR; P = .99). Kaplan-Meier estimates of 1-, 2-, and 3-year survival rates were also similar (50%, 50%, 42% REVAR vs 54%, 52%, 47% OSR; P = .66).

CONCLUSIONS

REVAR for rAAA does not seem to conclusively confer either acute or late survival advantages. Routine use of REVAR should be deferred until prospective, randomized trial data become available.

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 χ2 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.