Robert T. Lancaster

Preoperative functional status predicts perioperative outcomes after infrainguinal bypass surgery

OBJECTIVE Infrainguinal surgical bypass (BPG) is a durable method for lower extremity revascularization, but is accompanied by significant 30-day morbidity and mortality (MM). The goal of this study is to relate preoperative functional status, a defined metric in the National Surgical Quality Improvement Program (NSQIP) database, to perioperative MM. METHODS Between January 1, 2005 and December 31, 2007, all patients who underwent BPG from the NSQIP private sector database were reviewed. The primary end-point was 30-day MM. Patients were stratified by preoperative functional status: independent (IND) vs dependent (DEP). Associated patient demographic/clinical data were analyzed using univariate and multivariate methods. Composite odds ratios were constructed with clusters of high-risk comorbidities. RESULTS There were 5639 BPG patients (4600 [81.6%] IND and 1039 [18.4%]) DEP. DEP patients were significantly older (71.6 +/- 11.8 vs 66.8 +/- 11.8 years; P < .0001), had more chronic obstructive pulmonary disease (COPD) (16.7% vs 11.4%; P < .0001), diabetes (54.2% vs 40.7%; P < .0001), dialysis dependence (16.4% vs 5.6%; P < .0001), and critical limb ischemia (64.6% vs 44.0%; P < .0001). DEP patients had a higher incidence of death (6.1% vs 1.5%; P < .0001) and major complications (30.3% vs 14.2%; P < .0001). DEP was an independent predictor of major complications (odds ratio [OR]: 2.0; 95% confidence interval [CI]: [1.7-2.4]; P < .0001) major systemic complications (2.5 [1.9-3.2]; P < .0001), major operative site complications (1.6 [1.4-1.9]; P < .0001) and death (2.3[1.6-3.4]; P < .0001). The combination of DEP with emergency surgery, Cr > 1.8, or rest pain increased the odds of major complications by five, seven, or 11-fold, respectively. The combination of DEP with hemodialysis, emergency surgery, or age > or = 80 years increased the odds of death by 13, 38, or 87-fold, respectively. CONCLUSION Preoperative DEP is significantly correlated with all adverse 30-day outcomes in BPG patients. Furthermore, when combined in high-risk composites with specific preoperative clinical variables, DEP is associated with prohibitive MM, thereby identifying patient cohorts that may be unsuitable for BPG.

Impact of chronic kidney disease on outcomes after abdominal aortic aneurysm repair

OBJECTIVE Chronic kidney disease (CKD) is associated with increased morbidity and death after open abdominal aortic aneurysm (AAA) repair (OAR). This study highlights the effect of CKD on outcomes after endovascular AAA (EVAR) and OAR in contemporary practice. METHODS The National Surgical Quality Improvement Program (NSQIP) Participant Use File (2005-2008) was queried by Current Procedural Terminology (American Medical Association, Chicago, Ill) code to identify EVAR or OAR patients, who were grouped by CKD class as having mild (CKD class 1 or 2), moderate (CKD class 3), or severe (CKD class 4 or 5) renal disease. Propensity score analysis was performed to match OAR and EVAR patients with mild CKD with those with moderate or severe CKD. Comparative analysis of mortality and clinical outcomes was performed based on CKD strata. RESULTS We identified 8701 patients who were treated with EVAR (n = 5811) or OAR (n = 2890) of intact AAAs. Mild, moderate, and severe CKD was present in 63%, 30%, and 7%, respectively. CKD increased (P < .01) overall mortality, with rates of 1.7% (mild), 5.3% (moderate), and 7.7% (severe) in unmatched patients undergoing EVAR or OAR. Operative mortality rates in patients with severe CKD were as high as 6.2% for EVAR and 10.3% for OAR. Severity of CKD was associated with increasing frequency of risk factors; therefore, propensity matching to control for comorbidities was performed, resulting in similar baseline clinical and demographic features of patients with mild compared with those with moderate or severe disease. In propensity-matched cohorts, moderate CKD increased the risk of 30-day mortality for EVAR (1.9% mild vs 3.2% moderate; P = .013) and OAR (3.1% mild vs 8.4% moderate; P < .0001). Moderate CKD was also associated with increased morbidity in patients treated with EVAR (8.3% mild vs 12.8% moderate; P < .0001) or OAR (25.2% mild vs 32.4% moderate; P = .001). Similarly, severe CKD increased the risk of 30-day mortality for EVAR (2.6% mild vs 5.7% severe; P = .0081) and OAR (4.1% mild vs 9.9% severe; P = .0057). Severe CKD was also associated with increased morbidity in patients treated with EVAR (10.6% mild vs 19.2% severe; P < .0001) or OAR (31.1% mild vs 39.6% severe; P = .04). CONCLUSIONS The presence of moderate or severe CKD in patients considered for AAA repair is associated with significantly increased mortality and therefore should figure prominently in clinical decision making. The high mortality of AAA repair in patients with severe CKD is such that elective repair in such patients is not advised, except in extenuating clinical circumstances.

The better colectomy project: association of evidence-based best-practice adherence rates to outcomes in colorectal surgery.

Objective:To evaluate whether adherence to evidence-based best practices in colorectal surgery predicts improved postoperative outcomes. Summary and Background Data:Over a quarter of a million colon and rectal resections are performed annually in the United States. The average postoperative complication rate for these procedures approaches 30%. Methods:A panel of colorectal and general surgeons from 3 hospitals (1 academic medical center and 2 community hospitals) was assembled to ascertain a set of 37 evidence-based practices that they felt were the most pertinent to the evaluation and management of a patient undergoing a colorectal resection. Fifteen of these practices were classified as “key processes” for the prevention of complications. We then retrospectively reviewed medical records for 370 consecutive patients undergoing colorectal resection at these institutions. We evaluated the association of best-practice adherence to complications in the subset of patients with outcome data available through the American College of Surgeons National Surgical Quality Improvement Program. Results:Nonadherence rates exceeded 40% for 11 practices (including 2 key processes: avoidance of unnecessary blood transfusions and timely removal of central venous catheters). Among 198 patients with American College of Surgeons National Surgical Quality Improvement Program outcomes data, 38 (19%) experienced complications, of which 31 (82%) involved postoperative infection. Nonadherence to key-processes significantly predicted the occurrence of a complication (P = 0.002). Each additional process missed increased the odds of a postoperative complication by 60% (odds ratio: 1.6; 95% confidence interval: 1.2–2.2). Conclusions:Failures of adherence with best practices in colorectal surgery is associated with an increased occurrence of complications. This study merits further research to confirm that improvement in compliance with perioperative best practices will reduce complication rates significantly.

Comparable mortality with open repair of complex and infrarenal aortic aneurysm

BACKGROUND A consequence of endovascular aneurysm repair (EVAR) of anatomically straightforward infrarenal abdominal aortic aneurysm repair cohort (AAA) is that open aneurysm repair is more commonly performed for complex anatomy. Complex aneurysm repair with visceral vessel involvement (CAA) or combined aneurysm repair and visceral vessel reconstruction (VVR) has traditionally been considered to increase morbidity and mortality compared with repair of infrarenal AAA. This study evaluated contemporary outcomes of open abdominal aneurysm surgery, including AAA, CAA, and VVR using the National Surgical Quality Improvement Program (NSQIP) database. METHODS The NSQIP Participant Use File was queried by CPT code to identify patients undergoing AAA, CAA, and VVR (2005-2008). Comparative analysis of clinical features, technical details and 30-day outcomes was performed using univariate methods. Logistic regression analysis was used to identify predictors of morbidity and mortality. RESULTS A total of 2820 patients underwent AAA and 592 CAA. Renal insufficiency (ie, creatinine >1.4 mg/dL) rates were similar in AAA and CAA patients, however, more frequent in patients with VVR (51% vs 31% [no bypass]; P < .01). CAA was less likely to be performed urgently (6.3% vs 9.1%; P < .05) and was associated with increased operative time (254 ± 100 vs 224 ± 93; P < .01) compared with AAA. Univariate analysis showed that CAA did not increase mortality (5.7% vs 5.1%; P = .5). CAA slightly increased overall complications (32% vs 27%; P = .01) compared with AAA. 73 (2.5%) AAA and 84 (12%) CAA patients had simultaneous VVR and these patients exhibited a trend toward increased mortality (8.9% vs 5.2%; P = .07). VVR increased complications (43% (VVR) vs 26% [no bypass]; P < .01), including ventilation >48 hours (21% [VVR] vs 12% [no bypass]; P < .01), renal failure (7.6% [VVR] vs 4.1% [no bypass]; P = .04), and sepsis (13% [VVR] vs 6.3% ([no bypass]; P < .01). Multivariate analysis demonstrated that CAA (odds ratio [OR], 1.3 [95% confidence interval (CI), 1.1-1.6]; P = .01) and VVR (OR, 2.2 [95% CI, 1.8-3.6]; P < .01) increased the odds of any complication. Independent predictors of mortality included dependent functional status (OR, 3.6 [95% CI, 2.3-5.4]; P < .01), elevated pre-op creatinine (OR, 2.9 [95% CI, 2.2-4.0]; P < .01), type II diabetes (OR, 1.6 [95% CI, 1.05-2.4]; P = .03), and age (OR, 1.06 [95% CI, 1.03-1.08]; P < .01). Neither CAA (OR, 1.2 [95% CI, 0.84-1.8]; P = .3) nor VVR (OR, 1.6 [95% CI, 0.89-2.9]; P = .11) were associated with increased mortality compared with AAA. CONCLUSION In contemporary practice the migration of open repair to increasingly complex cases has been achieved with 30-day mortality essentially equivalent to open repair of infrarenal AAA. Patients who require VVR do sustain increased complications, in particular renal failure. These data also emphasize the importance of baseline renal insufficiency in clinical decision making. CAA and VVR are associated with increased morbidity in comparison to AAA repair; however, both procedures can be safely performed in patients without increased risk of operative mortality.

Further experience with distal aortic perfusion and motor-evoked potential monitoring in the management of extent I-III thoracoabdominal aortic anuerysms

BACKGROUND Prior studies indicated improved early mortality and paraplegia rates in a small cohort of patients with type I-III thoracoabdominal aortic aneurysms (TAAs) treated with atriofemoral bypass (AFB) and motor-evoked potentials (MEVPs) when compared with a propensity-matched cohort of patients treated with the clamp and sew (CS) method, wherein epidural cooling was the principal spinal cord protective adjunct. The use of AFB/MEVP increases the complexity of TAA repair and in this study, we address whether the early benefits will be sustained when this is applied to a general population with type I-III TAAs. METHODS Consecutive patients undergoing repair of nonruptured Crawford extent I-III TAAs from 1/1987 to 12/2011 were identified. Patients were stratified according to operative approach (AFB/MEVP vs CS). Endpoints included long-term survival, and the composite outcome of perioperative death and paraplegia. A multivariate, risk-adjusted model was then created to determine if operative approach independently influenced outcome. RESULTS There were 485 patients (CS = 385 [79%]; AFB/MEVP = 100 [21%]). The cohorts differed in that the AFB/MEVP group was younger (65.8 ± 12.5 years vs 70.9 ± 9.7 years; P < .001), had more extent I/II aneurysms (66% vs 50.1%; P = .005), and had more chronic dissections (30.3% vs 18.9%; P = .018). Operative variables differed in that the AFB/MEVP cohort had longer operative times (434 ± 112 minutes vs 324 ± 98 minutes; P < .001) and higher blood turnover (6028 ± 3473 mL vs 3581 ± 3111 mL; P < .0001). There was no difference in the rate of intraoperative death (AFB/MEVP = 1.0% vs CS = 0.5%; P = .50), length of intensive care unit stay (AFB/MEVP = 9.6 ± 8.6 days vs CS = 9.5 ± 12.3 days; P = .95) or hospital length of stay (AFB/MEVP = 19.9 ± 12.6 days vs CS = 21.6 ± 23.5 days; P = .49). The composite perioperative death and paraplegia rate was lower in the AFB/MEVP cohort (7% vs 19%; P = .004). The multivariate model for predictors of the composite outcome showed that AFB/MEVP was protective (odds ratio, 0.39; 95% confidence interval, 0.17-0.9; P = .028). Long-term (4-year) survival was improved in the AFB/MEVP group as well (73 ± 6% vs 60 ± 3%; P = .004). CONCLUSIONS AFB/MEVP is an independent predictor of improved perioperative death and paraplegia rates as well as long-term survival in patients undergoing repair of type I-III TAAs and is the preferred operative strategy.

Open surgical repair of thoracoabdominal aneurysms - the Massachusetts General Hospital experience.

The modern era of surgical management of thoracoabdominal aneurysms (TAA) began with the pioneering work of E. Stanley Crawford (1); this benchmark series reported an operative mortality of 10% with an incidence of spinal cord ischemia (SCI) of 16%, some 50% of which were total paraplegia. Over a 20 year period until 2006, TAA repair at our institution (2) was predominantly performed using a simplified clamp and sew approach in accordance with Dr. Crawford’s teachings which emphasized operative expediency and technical efficiency (2). Management of TAA during this time was typically performed without use of distal perfusion techniques. Adjunct use included routine cerebrospinal fluid (CSF) drainage (3,4), aggressive intercostal re-implantation (3,5,6), regional hypothermia for spinal cord protection (7,8), infusion of hypothermic renal preservation fluid for prevention of renal failure, and in-line mesenteric shunting (9) to reduce complications resulting from visceral ischemia. Using this approach we achieved favorable results with an overall operative mortality of 8% (6% elective and 13% urgent) with significant SCI in 8% of patients (2). Largely driven by the apparent failure of epidural cooling to drive SCI to less than 5%, we modified operative management of TAA in recent years in an effort to further reduce spinal cord complications. As our experience has shown (10) that patients with type IV TAA can safely be managed with a simplified clamp/sew approach with favorable results, this evolution in operative strategy has been exclusively implemented in management of patients with extents I-III TAA. In essence the rationale exploited the collateral network concept (11-13): we adopted routine use of distal aortic perfusion (DAP) via left atrial to femoral bypass to support the collateral circulation to the spinal cord during the period of aortic cross clamp application. Additionally, intra-operative motor evoked potential (MEP) monitoring (14,15) has afforded the ability to dynamically assess spinal cord ischemia during aneurysm reconstruction. As a result, we have abandoned aggressive intercostal re-implantation in favor of a selective MEP driven re-implantation strategy. Clinical outcomes resulting from this evolution in operative strategy for extents I-III TAA have recently been published and are further highlighted herein (16).

Two Routine Blood Tests—mean Corpuscular Volume and Aspartate Aminotransferase—as Predictors of Delirium Tremens in Trauma Patients

BACKGROUND Delirium tremens (DT) in trauma patients is associated with significant morbidity and mortality. Short interview tools have been used to determine the risk of DT but require an alert, compliant patient and a motivated physician. The mean corpuscular volume (MCV) and aspartate aminotransferase (AST) levels are parts of routine laboratory testing, influenced by excessive alcohol consumption, and may serve as predictors of DT. This study examines the predictive ability of these two readily available biological markers. METHODS The records of 423 consecutive trauma patients who presented to a Level I trauma center with a positive toxicology screen for alcohol were reviewed. The outcome variable was DT, as defined by the presence of tremor, diaphoresis, autonomic instability, and hallucinations. The positive predictive value (PPV), negative predictive value (NPV), and likelihood ratio (LR) of the admission MCV and AST values were calculated for the prediction of DT. RESULTS Of the 336 patients who met the criteria for study participation, 110 were diagnosed with DT due to alcohol withdrawal. When the admission MCV and AST were normal, only 3 patients (3.8%) developed DT. The NPV, PPV, and LR with two normal values together were 58.2%, 3.8%, and 0.080, respectively. When both were abnormal, 72 patients (64.3%) developed DT. The NPV, PPV, and LR with two abnormal values together were 83%, 64.3%, and 3.698, respectively. CONCLUSION Normal admission MCV and AST values in intoxicated trauma patients nearly exclude the development of DT.

Postoperative renal dysfunction independently predicts late mortality in patients undergoing aortic reconstruction.

OBJECTIVE Preoperative chronic kidney disease (CKD) has been shown to predict postoperative renal complications and mortality after open aortic surgery; the impact of postoperative renal complications less severe than permanent dialysis are unknown. We evaluated the impact of postoperative renal dysfunction severity on survival using a regional quality improvement registry. METHODS Patients undergoing intact open aortic reconstruction in the Vascular Study Group of New England registry (2003-2012) were stratified by severity of postoperative renal complications; none, creatinine increase of greater than 0.5 mg/dL (incCr), or any hemodialysis (HD). Predictors of renal dysfunction and impact of renal complications on survival were analyzed using multivariable methods. RESULTS We included 2695 patients, of which 65% (n = 1733) underwent open abdominal aortic aneurysm repair, and 35% (n = 962) open aortoiliac reconstruction. At baseline, 15% of patients had preoperative moderate CKD and 1.2% had severe CKD. Postoperative renal complications of incCr occurred in 8.5% of patients, and 1.5% required HD. Multivariable cumlogit regression identified severe baseline CKD (odds ratio [OR], 15; 95% confidence interval [CI], 6.4-34; P < .001, moderate CKD (OR, 2.8; 95% CI, 1.9-3.3; P < .001), suprarenal clamp use (OR, 2.2; 95% CI, 1.6-2.9; P < .001), perioperative vasopressor requirements (OR, 2.2; 95% CI, 1.6-2.9; P < .001), operating time (OR, 1.004 per minute; 95% CI, 1.003-1.006; P < .001), and chronic obstructive pulmonary disease (OR, 1.5; 95% CI, 1.2-1.8; P < .001) as independent predictors of worsening strata of postoperative renal dysfunction. Multivariable logistic regression analysis showed that patient age (OR, 1.06 per year; 95% CI, 1.01-1.1; P = .01), baseline chronic obstructive pulmonary disease (OR, 1.6; 95% CI, 1.2-2.2; P < .01), incCr (OR, 3.7; 95% CI, 1.8-7.4; P = .009), and HD (OR, 4.8; 95% CI, 1.8-12.7); P = .009) independently increased 30-day mortality. Risk-adjusted multivariable Cox regression showed that incCr (hazard ratio, 1.8; 95% CI, 1.3-2.6; P < .001) and HD (hazard ratio, 4.4; 95% CI, 2.8-6.9; P < .001) increased risk of late death independent of a variety of other clinical variables, including baseline CKD. The 5-year survival was lower (log-rank P < .001) in patients with incCr (66% ± 4%), and HD (38% ± 10%) compared with those with no renal complications (77% ± 1%). CONCLUSIONS Increasing severity of postoperative renal dysfunction independently predicts increased risk of late mortality after open aortic surgery. Perioperative measures to decrease renal complications may potentially prolong the survival of patients after open aortic surgery.

Extended motor evoked potentials monitoring helps prevent delayed paraplegia after aortic surgery

Motor evoked potentials (MEPs) monitoring can promptly detect spinal cord ischemia (SCI) from aortic clamping during open thoracoabdominal aneurysm repair (OTAAR) with distal aortic perfusion (DAP) and thus help decrease the risk of immediate postoperative SCI (IP‐SCI). However, neither stable MEPs during aortic clamp interval (ACI) nor absence of IP‐SCI eliminate the possibility of delayed postoperative SCI (DP‐SCI). We hypothesized that extension of MEPs monitoring beyond ACI can also help decrease the risk of DP‐SCI.

Chronic Kidney Disease Class Predicts Mortality After Abdominal Aortic Aneurysm Repair in Propensity-matched Cohorts From the Medicare Population.

Introduction: Chronic kidney disease (CKD) predicts mortality after abdominal aortic aneurysm (AAA) repair. Few studies are adequately powered to stratify outcomes by CKD severity. This study assesses the effect of CKD severity on survival after AAA repair. Methods: Patients who underwent AAA repair from 2006 to 2007 were retrospectively identified in the Medicare database and stratified by CKD class as follows: normal (CKD class 1 and 2), moderate (CKD class 3), and severe (CKD class 4 and 5). Propensity matching (30:1) by clinical factors and procedure type was performed to derive well-matched comparative cohorts. Primary outcomes were 30-day and long-term mortality; secondary outcomes included hospital length of stay and cost. Results: A total of 47,715 patients were included (96.7% normal, 1.88% moderate, and 1.65% severe). Propensity matching was corrected for differences between cohorts. Thirty-day mortality was higher in moderate (5.7% vs normal 2.5%; P < 0.01) and severe (9.9% vs normal 1.8%; P < 0.01) groups. Hospital length of stay increased with CKD severity (4.4 ± 3.7 days normal vs 6.5 ± 4.2 days moderate CKD; P < 0.01/4.7 ± 3.8 days normal vs 9.1 ± 4.5 days severe CKD; P < 0.01) as did cost (