The Impact of Acute Renal Failure on Early and Late Outcomes After Thoracic Aortic Endovascular Repair Joseph D. Drews, BS, Himanshu J. Patel, MD, David M. Williams, MD, Narasimham L. Dasika, MD, and G. Michael Deeb, MD Departments of Cardiac Surgery and Radiology, University of Michigan Frankel Cardiovascular Center, Ann Arbor, Michigan
Background. The incidence of acute kidney injury (AKI) after thoracic aortic endovascular repair (TEVAR) is variably reported at 1% to 34%. This study utilized the RIFLE (risk, injury, failure) criteria to evaluate the incidence, risk factors, and late implications of AKI after TEVAR. Methods. In all, 350 patients without prior dialysis requirement underwent TEVAR (1993 to 2013). The mean age was 68.7 years (54% male). The mean preoperative glomerular filtration rate was 76.5 ± 37.6 mL/min, with 39 patients (11.7%) in chronic kidney stage 3 or 4. The TEVAR was performed for rupture in 20.6%. The mean contrast volume administered was 95.7 ± 52.9 mL. Results. Early mortality was seen in 17 patients (4.9%). Acute kidney injury defined as RIFLE classes risk, injury, or failure was seen in 59 patients (17%; risk [ 36, injury [ 14, failure [ 9). Independent predictors of AKI included history of saccular aneurysm, presentation with
rupture, or need for arch repair or red blood cell transfusion (all p < 0.05). Only 2 patients (0.6%) needed dialysis, with none requiring permanent dialysis. Importantly, 10-year freedom from dialysis was 97.7%. Development of AKI predicted early mortality (p < 0.001, odds ratio 9.8). Ten-year survival was 38.1%. Both injury and failure AKI classes independently predicted late mortality (p < 0.05). Conclusions. The prevalence of AKI after TEVAR as assessed by RIFLE criteria is higher than seen in previous reports. Despite its infrequent progression to permanent dialysis dependence, AKI remains an important risk factor for both early and late mortality. Future studies should evaluate strategies to reduce the incidence of AKI after TEVAR to improve both early and late outcomes.
P
arteries, lack of long-term data, and also variability in definitions of renal failure [1–9]. The recently popularized RIFLE consensus criteria (risk, injury, failure, loss, end stage) provide an important consistent standard by which to evaluate perioperative renal insufficiency [10, 11]. We, therefore, undertook this study to review the incidence, risk factors, and impact of AKI occurring after TEVAR over a 20-year period.
erioperative acute kidney injury (AKI) remains an important source of morbidity after thoracic aortic repair [1–3]. Several studies have evaluated the impact of AKI on open thoracic aortic resection, but limited conflicting data exist on its frequency after thoracic aortic endovascular repair (TEVAR) [1–9]. This latter therapeutic option has emerged as an important less invasive treatment for a wide range of thoracic aortic disease [4, 6, 7]. Presumably, the avoidance of extracorporeal support or even deep hypothermic circulatory arrest, aortic crossclamp placement, and much smaller incisions with a reduction in their associated hemodynamic shifts may potentially diminish the incidence of AKI. Important factors such as administration of intravascular contrast may increase the risk of AKI. Recent reports have evaluated the incidence of AKI after TEVAR, but have been criticized by inclusion of extensive thoracoabdominal pathology involving renal
Accepted for publication Feb 20, 2014.
(Ann Thorac Surg 2014;-:-–-) Ó 2014 by The Society of Thoracic Surgeons
Material and Methods This study was approved by the Institutional Review Board of the University of Michigan Hospitals (HUM00048332). Informed consent requirements were waived. Data from all patients admitted to the University of Michigan Hospitals who underwent TEVAR between 1993 and 2013 were retrospectively analyzed. Exclusion criteria included (1) a history of dialysis-dependent renal failure; (2) extensive thoracoabdominal aortic pathology requiring treatment into the pararenal aortic segment; (3)
Presented at the Sixtieth Annual Meeting of the Southern Thoracic Surgical Association, Scottsdale, AZ, Oct 30–Nov 2, 2013. Address correspondence to Dr Patel, Department of Cardiac Surgery, CVC Rm 5144, 1500 E Medical Center Dr, SPC 5864, Ann Arbor, MI 481095864; e-mail: [email protected].
Ó 2014 by The Society of Thoracic Surgeons Published by Elsevier Inc
Drs Williams and Patel disclose financial relationships with WL Gore and Associates.
0003-4975/$36.00 http://dx.doi.org/10.1016/j.athoracsur.2014.02.045
2
DREWS ET AL INCIDENCE OF AKI AFTER TEVAR
need for adjunctive arch debranching through median sternotomy with or without the use of extracorporeal support; and (4) associated off-pump coronary artery bypass graft surgery. With these criteria, 350 patients formed the study cohort. Indications for TEVAR included fusiform (108) or saccular aneurysms (81), anastomotic pseudoaneurysms (12), penetrating atherosclerotic ulcers (26), acute or subacute (55) and chronic (29) type B dissections, and blunt thoracic aortic injury (35). The remaining 18 patients had other indications including treatment of atheroembolism, Kommerell’s diverticulum, iatrogenic injuries, and postcoarctation aneurysms. More than one indication was present in 19 patients. Nontraumatic aortic rupture was present in 72 patients (20.5%). Twentynine patients (8.1%) presented with aortic infections, including fistulas (14) and mycotic aneurysms (15). The TEVAR was performed as previously described. Brief controlled hypotension was utilized during device deployment, and then again if balloon aortoplasty was performed. Treatment was extended into the arch in 189 patients (54.0%). Extensive aneurysms were present requiring treatment of the total descending aorta in 163 (46.6%), or visceral segment in 16 (4.6%). Open retroperitoneal visceral debranching was required in 4 patients, including concomitantly in 1. Understanding the long duration of the study and evolving treatment strategies, renal protection for all patients was undertaken as follows. Those presenting with nonemergent status and preoperative creatinine greater than 2.0 mg/dL underwent preoperative hydration with a standardized protocol. N-acetylcysteine was used variably during the long study period and at the discretion of the operating physician. During the procedure, attempts were made to reduce intraarterial contrast load in all patients with adjunctive use of intravascular ultrasonography, selective branch vessel cannulation to mark and identify critical branch vessels, use of CO2 arteriography, and use of bony landmarks where appropriate at the discretion of the operating team. All patients received nonionic low osmolar contrast media during the procedure. The mean dye load for the entire cohort was 95.7 52.9 mL. The primary outcome of this study was occurrence of acute kidney injury after TEVAR. Acute kidney injury was defined according to the consensus RIFLE criteria set forth by the Acute Dialysis Quality Initiative Group identifying three grades of severity (risk, injury, and failure) as well as two outcome classifications (loss and end-stage failure) [10, 11]. The basis for this was the change in glomerular filtration rate (GFR) estimated by the Modification of Diet in Renal Disease formula and serum creatinine during the postoperative period. Other evaluated outcomes of interest included early (in-hospital or 30-day) and late mortality; and other morbidity, including rates of stroke and spinal cord ischemia. Data were collected from patient hospital records and imaging studies, and late mortality was verified by interrogation of the Social Security Death Index. Follow-up for the primary outcome was 99.2% complete, and late mortality
Ann Thorac Surg 2014;-:-–-
was verified as of September 2013 at a mean of 39.8 35.5 months.
Statistical Analysis Data were analyzed using SPSS software (SPSS Inc, Chicago, IL). Dichotomous variables were evaluated using c2 analysis or Fisher’s exact test; continuous variables were evaluated using Student’s t test. Multivariate models (binary logistic regression) were constructed using a forward conditional process to identify factors that were independently associated with each of the outcomes of interest. Factors utilized in multivariate analysis included those with p less than 0.1 significance on univariate analysis. Survival analysis was performed by KaplanMeier (with Wilcoxon comparison test) and Cox regression methods. All results with p less than 0.05 were considered statistically significant.
Results The mean age of the entire cohort was 68.7 13.7 years (54% male). Demographics and comorbidities are listed in Table 1. Rates of cardiovascular comorbid conditions ranged from 12.6% for carotid disease to 79.1% for hypertension. The mean preoperative GFR was 76.5 37.6 mL/min. Thirty-three patients (9.4%) were in chronic kidney disease stage III (GFR
Background. The incidence of acute kidney injury (AKI) after thoracic aortic endovascular repair (TEVAR) is variably reported at 1% to 34%. This study utilized the RIFLE (risk, injury, failure) criteria to evaluate the incidence, risk factors, and late implications of AKI after TEVAR. Methods. In all, 350 patients without prior dialysis requirement underwent TEVAR (1993 to 2013). The mean age was 68.7 years (54% male). The mean preoperative glomerular filtration rate was 76.5 ± 37.6 mL/min, with 39 patients (11.7%) in chronic kidney stage 3 or 4. The TEVAR was performed for rupture in 20.6%. The mean contrast volume administered was 95.7 ± 52.9 mL. Results. Early mortality was seen in 17 patients (4.9%). Acute kidney injury defined as RIFLE classes risk, injury, or failure was seen in 59 patients (17%; risk [ 36, injury [ 14, failure [ 9). Independent predictors of AKI included history of saccular aneurysm, presentation with
rupture, or need for arch repair or red blood cell transfusion (all p < 0.05). Only 2 patients (0.6%) needed dialysis, with none requiring permanent dialysis. Importantly, 10-year freedom from dialysis was 97.7%. Development of AKI predicted early mortality (p < 0.001, odds ratio 9.8). Ten-year survival was 38.1%. Both injury and failure AKI classes independently predicted late mortality (p < 0.05). Conclusions. The prevalence of AKI after TEVAR as assessed by RIFLE criteria is higher than seen in previous reports. Despite its infrequent progression to permanent dialysis dependence, AKI remains an important risk factor for both early and late mortality. Future studies should evaluate strategies to reduce the incidence of AKI after TEVAR to improve both early and late outcomes.
P
arteries, lack of long-term data, and also variability in definitions of renal failure [1–9]. The recently popularized RIFLE consensus criteria (risk, injury, failure, loss, end stage) provide an important consistent standard by which to evaluate perioperative renal insufficiency [10, 11]. We, therefore, undertook this study to review the incidence, risk factors, and impact of AKI occurring after TEVAR over a 20-year period.
erioperative acute kidney injury (AKI) remains an important source of morbidity after thoracic aortic repair [1–3]. Several studies have evaluated the impact of AKI on open thoracic aortic resection, but limited conflicting data exist on its frequency after thoracic aortic endovascular repair (TEVAR) [1–9]. This latter therapeutic option has emerged as an important less invasive treatment for a wide range of thoracic aortic disease [4, 6, 7]. Presumably, the avoidance of extracorporeal support or even deep hypothermic circulatory arrest, aortic crossclamp placement, and much smaller incisions with a reduction in their associated hemodynamic shifts may potentially diminish the incidence of AKI. Important factors such as administration of intravascular contrast may increase the risk of AKI. Recent reports have evaluated the incidence of AKI after TEVAR, but have been criticized by inclusion of extensive thoracoabdominal pathology involving renal
Accepted for publication Feb 20, 2014.
(Ann Thorac Surg 2014;-:-–-) Ó 2014 by The Society of Thoracic Surgeons
Material and Methods This study was approved by the Institutional Review Board of the University of Michigan Hospitals (HUM00048332). Informed consent requirements were waived. Data from all patients admitted to the University of Michigan Hospitals who underwent TEVAR between 1993 and 2013 were retrospectively analyzed. Exclusion criteria included (1) a history of dialysis-dependent renal failure; (2) extensive thoracoabdominal aortic pathology requiring treatment into the pararenal aortic segment; (3)
Presented at the Sixtieth Annual Meeting of the Southern Thoracic Surgical Association, Scottsdale, AZ, Oct 30–Nov 2, 2013. Address correspondence to Dr Patel, Department of Cardiac Surgery, CVC Rm 5144, 1500 E Medical Center Dr, SPC 5864, Ann Arbor, MI 481095864; e-mail: [email protected].
Ó 2014 by The Society of Thoracic Surgeons Published by Elsevier Inc
Drs Williams and Patel disclose financial relationships with WL Gore and Associates.
0003-4975/$36.00 http://dx.doi.org/10.1016/j.athoracsur.2014.02.045
2
DREWS ET AL INCIDENCE OF AKI AFTER TEVAR
need for adjunctive arch debranching through median sternotomy with or without the use of extracorporeal support; and (4) associated off-pump coronary artery bypass graft surgery. With these criteria, 350 patients formed the study cohort. Indications for TEVAR included fusiform (108) or saccular aneurysms (81), anastomotic pseudoaneurysms (12), penetrating atherosclerotic ulcers (26), acute or subacute (55) and chronic (29) type B dissections, and blunt thoracic aortic injury (35). The remaining 18 patients had other indications including treatment of atheroembolism, Kommerell’s diverticulum, iatrogenic injuries, and postcoarctation aneurysms. More than one indication was present in 19 patients. Nontraumatic aortic rupture was present in 72 patients (20.5%). Twentynine patients (8.1%) presented with aortic infections, including fistulas (14) and mycotic aneurysms (15). The TEVAR was performed as previously described. Brief controlled hypotension was utilized during device deployment, and then again if balloon aortoplasty was performed. Treatment was extended into the arch in 189 patients (54.0%). Extensive aneurysms were present requiring treatment of the total descending aorta in 163 (46.6%), or visceral segment in 16 (4.6%). Open retroperitoneal visceral debranching was required in 4 patients, including concomitantly in 1. Understanding the long duration of the study and evolving treatment strategies, renal protection for all patients was undertaken as follows. Those presenting with nonemergent status and preoperative creatinine greater than 2.0 mg/dL underwent preoperative hydration with a standardized protocol. N-acetylcysteine was used variably during the long study period and at the discretion of the operating physician. During the procedure, attempts were made to reduce intraarterial contrast load in all patients with adjunctive use of intravascular ultrasonography, selective branch vessel cannulation to mark and identify critical branch vessels, use of CO2 arteriography, and use of bony landmarks where appropriate at the discretion of the operating team. All patients received nonionic low osmolar contrast media during the procedure. The mean dye load for the entire cohort was 95.7 52.9 mL. The primary outcome of this study was occurrence of acute kidney injury after TEVAR. Acute kidney injury was defined according to the consensus RIFLE criteria set forth by the Acute Dialysis Quality Initiative Group identifying three grades of severity (risk, injury, and failure) as well as two outcome classifications (loss and end-stage failure) [10, 11]. The basis for this was the change in glomerular filtration rate (GFR) estimated by the Modification of Diet in Renal Disease formula and serum creatinine during the postoperative period. Other evaluated outcomes of interest included early (in-hospital or 30-day) and late mortality; and other morbidity, including rates of stroke and spinal cord ischemia. Data were collected from patient hospital records and imaging studies, and late mortality was verified by interrogation of the Social Security Death Index. Follow-up for the primary outcome was 99.2% complete, and late mortality
Ann Thorac Surg 2014;-:-–-
was verified as of September 2013 at a mean of 39.8 35.5 months.
Statistical Analysis Data were analyzed using SPSS software (SPSS Inc, Chicago, IL). Dichotomous variables were evaluated using c2 analysis or Fisher’s exact test; continuous variables were evaluated using Student’s t test. Multivariate models (binary logistic regression) were constructed using a forward conditional process to identify factors that were independently associated with each of the outcomes of interest. Factors utilized in multivariate analysis included those with p less than 0.1 significance on univariate analysis. Survival analysis was performed by KaplanMeier (with Wilcoxon comparison test) and Cox regression methods. All results with p less than 0.05 were considered statistically significant.
Results The mean age of the entire cohort was 68.7 13.7 years (54% male). Demographics and comorbidities are listed in Table 1. Rates of cardiovascular comorbid conditions ranged from 12.6% for carotid disease to 79.1% for hypertension. The mean preoperative GFR was 76.5 37.6 mL/min. Thirty-three patients (9.4%) were in chronic kidney disease stage III (GFR
