Jae S. Cho

Outcomes of endovascular abdominal aortic aneurysm repair in high-risk patients

OBJECTIVEnAlthough the endovascular aneurysm repair trial 2 (EVAR-2) demonstrated no benefit of EVAR in high-risk (HR) patients, EVAR is still performed widely in this patient cohort. This study compares the midterm outcomes after EVAR in HR patients with those in normal-risk (NR) patients. In turn, these data are compared with the EVAR-2 data.nnnMETHODSnA retrospective review from January 2006 to December 2013 identified 247 patients (75 HR [30.4%], 172 NR [69.6%]) who underwent elective EVAR for infrarenal aortic aneurysm in an academic tertiary institution and its affiliated Veterans Administration hospital. The same HR criteria used in the EVAR-2 trial were employed. Overall survival, graft-related complications, and reintervention rates were estimated by the Kaplan-Meier method. HR group outcomes were compared with the EVAR-2 data.nnnRESULTSnHR patients had a larger abdominal aortic aneurysm size and had a higher prevalence of cardiac disease (P < .01), chronic obstructive pulmonary disease (P = .02), renal insufficiency (P < .01), and cancer (P < .01). Use of aspirin (63% HR vs 66% NR; P = .6), statin (83% HR vs 72% NR; P = .2), and beta-blockers (71% HR vs 60% NR; P = .2) was similar; in the EVAR-2 trial, the corresponding use of these medications was 58%, 42%, and not available, respectively. Perioperative mortality (0% HR vs 1.2% NR; P = 1.0) and early complication rates (4% HR vs 6% NR; P = .8) were similar. In contrast, perioperative mortality in the EVAR-2 trial was 9%. At a mean follow-up of 3 years, the incidence rates of delayed secondary interventions for aneurysm- or graft-related complications were 7% for HR patients and 10% for NR patients (P = .5). The 1-, 2-, and 4-year survival rates in HR patients (85%, 77%, 65%) were lower than those in NR patients (97%, 97%, 93%; P < .001), but this was more favorable compared with a 36% 4-year survival in the EVAR-2 trial. No difference was seen in long-term reintervention-free survival in HR and NR patients (P = .8). Backward stepwise logistic regression analysis identified five prognostic indicators for post-EVAR death: age, chronic kidney disease stages 4 and 5, congestive heart failure, home oxygen use, and current cancer therapy.nnnCONCLUSIONSnEVAR can be performed in patients unfit for open surgical repair with excellent early survival and long-term durability. These outcomes in the HR group compare more favorably to the EVAR-2 trial data. However, not all HR patients for open surgical repair derive the benefit from EVAR. The decision to proceed with EVAR in HR patients should be individualized, depending on the number and severity of risk factors.

Spontaneous Ruptured Dissection of the Right Common Iliac Artery in a Patient with Classic Ehlers–Danlos Syndrome Phenotype

Unlike vascular Ehlers-Danlos syndrome (EDS), classic EDS is rarely associated with vascular manifestation. We report the case of a 39-year-old man who presented with acute abdominal pain. At the time of presentation, the patient was in hypovolemic shock, and computed tomography angiogram demonstrated common iliac artery dissection with rupture. He underwent an attempted endovascular repair that was converted to an open repair of a ruptured right common iliac artery dissection. Subsequent genetic testing revealed a substitution of arginine for cysteine in type I collagen, COL1A1 exon 14 c.934C>T mutation, consistent with a rare variant of classic EDS.

Neurologic complications of aortic diseases and aortic surgery.

Aortic disease processes have a wide range of clinical manifestations. The inflammatory disease process of Takayasus arteritis differs dramatically from the visceral ischemia of aortic dissection. The catastrophic event of aortic rupture tends to overshadow life-altering events such as stroke and paraplegia. However, these neurologic manifestations of aortic diseases have dramatic effects that extend beyond the individual patient to include both social and financial ramifications. This chapter focuses on the major aortic disease processes and how they can initiate, both directly and indirectly, adverse neurologic events. The chapter concludes with a brief discussion of aortic surgery, how interventions on the aorta can cause neurologic complications, and techniques to avoid these feared adverse neurologic outcomes.

Abdominal Aortic Aneurysm Associated with Congenital Solitary Pelvic Kidney Treated with Novel Hybrid Technique

Renal ectopia in the rare condition of associated abdominal aortic aneurysm presents a difficult clinical challenge with respect to access to the aorto-iliac segment and preservation of renal function because of its anomalous renal arterial anatomy and inevitable renal ischemia at the time of open repair. Multiple operative techniques are described throughout the literature to cope with both problems. We report a case of a 57-year-old male with an aorto-iliac aneurysm and a congenital solitary pelvic kidney successfully treated by hybrid total renal revascularization using iliorenal bypass followed by unilateral internal iliac artery coil embolization and conventional endovascular aortic aneurysm repair without any clinical evidence of renal impairment.

Transient postoperative atrial fibrillation after abdominal aortic aneurysm repair increases mortality risk

OBJECTIVEnThe purpose of this study was to determine whether new-onset transient postoperative atrial fibrillation (TPAF) affects mortality rates after abdominal aortic aneurysm (AAA) repair and to identify predictors for the development of TPAF.nnnMETHODSnPatients who underwent open aortic repair or endovascular aortic repair for a principal diagnosis AAA were retrospectively identified using the Healthcare Cost and Utilization Project-State Inpatient Database (Florida) for 2007 to 2011 and monitored longitudinally for 1xa0year. Inpatient and 1-year mortality rates were compared between those with and without TPAF. TPAF was defined as new-onset atrial fibrillation that developed in the postoperative period and subsequently resolved in patients without a history of atrial fibrillation. Cox proportional hazards models, adjusted for age, gender, comorbidities, rupture status, and repair method, were used to assess 1-year survival. Predictive models were built with preoperative patient factors using Chi-squared Automatic Interaction Detector decision trees and externally validated on patients from California.nnnRESULTSnA 3.7% incidence of TPAF was identified among 15,148 patients who underwent AAA repair. The overall mortality rate was 4.3%. The inpatient mortality rate was 12.3% in patients with TPAF vs 4.0% in those without TPAF. In the ruptured setting, the difference in mortality was similar between groups (33.7% vs 39.9%, Pxa0= .3). After controlling for age, gender, comorbid disease severity, urgency (ruptured vs nonruptured), and repair method, TPAF was associated with increased 1-year postoperative mortality (hazard ratio, 1.48; Pxa0< .001) and postdischarge mortality (hazard ratio, 1.56; Pxa0= .028). Chi-squared Automatic Interaction Detector-based models (C statisticxa0= 0.70) were integrated into a Web-based application to predict an individuals probability of developing TPAF at the point of care.nnnCONCLUSIONSnThe development of TPAF is associated with an increased risk of mortality in patients undergoing repair of nonruptured AAA. Predictive modeling can be used to identify those patients at highest risk for developing TPAF and guide interventions to improve outcomes.

Comparison of supramesenteric aortic cross-clamping with supraceliac aortic cross-clamping for aortic reconstruction

OBJECTIVEnSupraceliac aortic cross-clamping (SCXC) is routinely used during open aortic reconstruction (OAR) of pararenal aortic disease when suprarenal control is not feasible. On occasion, however, aortic control may be obtained at the supramesenteric level by supramesenteric cross-clamping (SMXC) between the superior mesenteric artery and the celiac axis. The purpose of this study was to compare outcomes between patients who had SMXC vs SCXC during OAR for both aneurysmal and occlusive diseases.nnnMETHODSnA retrospective chart review identified 69 patients who underwent elective OAR requiring SMXC (nxa0= 18) or SCXC (nxa0= 51). All patients with thoracoabdominal aneurysms and those who had inframesenteric (suprarenal and infrarenal) aortic control were excluded. Propensity score-based matching was performed to adjust for confounding factors in a 1:1 ratio to compare outcomes. Late survival was estimated by Kaplan-Meier methods.nnnRESULTSnPropensity score-based matching was performed at a 1:1 ratio; 18 SMXC cases were matched with 18 SCXC cases. The average age was 66.7xa0years, and men constituted 72%. Baseline characteristics were matched, except for the incidence of peripheral vascular occlusive disease (72.2% in the SMXC group vs 33.3% in the SCXC group; Pxa0= .04). A majority (80.6%) of patients underwent OAR for aneurysmal disease (72.2% in the SMXC group, 88.9% in the SCXC group). Intraoperatively, there were no differences in operative times (325xa0minutes for SMXC vs 298xa0minutes for SCXC; Pxa0=xa0.48), but the SMXC group had a longer renal ischemia time (40xa0minutes vs 28xa0minutes; Pxa0= .03). There were no significant differences in intraoperative blood loss (2.4xa0L vs 1.6xa0L; Pxa0= .2) or blood product transfusion requirements (packed red blood cells, 2.2 units vs 1.6 units [Pxa0= .5]; Cell Saver, 1.3xa0L vs 0.7xa0L [Pxa0= .09]). Overall complication rates did not differ significantly (27.8% for SMXC vs 44.4% for SCXC; Pxa0= .24). Thirty-day mortality rates did not differ between the two groups (0% for SMXC vs 5.6% for SCXC; Pxa0= 1).nnnCONCLUSIONSnIn this study, there were no differences in early morbidity or mortality between SMXC and SCXC during aortic reconstruction. SMXC, however, can be performed safely and effectively in properly selected patients. A larger, multicenter prospective study would help elucidate the potential benefits.

Synthetic, organic compound vepoloxamer (P-188) potentiates tissue plasminogen activator

Objective Poloxamer‐188 is a synthetic, organic compound that acts by binding hydrophobic pockets on damaged lipid bilayers in the circulation. P‐188 reduces blood viscosity and confers anti‐inflammatory and cytoprotective effects. Vepoloxamer (Mast Therapeutics, San Diego, Calif) is a purified version of this compound that has limited side effects. The aim of this study was to investigate drug interactions between vepoloxamer and heparin and tissue plasminogen activator (tPA). Methods An experimental rat tail transection model was used to study vepoloxamers interaction with heparin. Sprague‐Dawley rats were divided into saline (1 mL/kg; group 1) or vepoloxamer (25 mg/kg; group 2) treatment groups. The rats were then subjected to saline (n = 6), low‐dose heparin (125 &mgr;g/kg; n = 6), or high‐dose heparin (250 &mgr;g/kg; n = 6). After 5 minutes, the distal 2 mm of the tail was transected, and time to clot formation was measured as bleeding time. A rat internal jugular vein thrombosis model was used to assess vepoloxamers interaction with tPA. Sprague‐Dawley rats were divided into saline (1 mL/kg; group 1) or vepoloxamer (25 mg/kg; group 2) treatment groups. After internal jugular vein thrombosis, rats were treated with saline (n = 6), systemic low‐dose tPA (0.5 mg/kg; n = 6), or systemic high‐dose tPA (1.0 mg/kg; n = 6). Clot lysis was assessed using an ultrasound Doppler probe to detect blood flow. No flow up to 15 minutes was recorded as no lysis. Results Interaction with heparin: Vepoloxamer by itself, without any heparin, increased tail bleeding time (10.3 vs 7.1 minutes; P = .001). Effects of heparin on tail bleeding time were enhanced by vepoloxamer at low dose (14.2 vs 6.2 minutes; P < .001). At high‐dose heparin, vepoloxamer did not prolong bleeding time (17.8 vs 17.0 minutes). Interaction with tPA: No rat exhibited spontaneous clot lysis with either saline or vepoloxamer. The effect of tPA was facilitated by vepoloxamer at low dose, as more rats showed clot lysis (4/6 [66%]) compared with tPA alone, which showed no clot lysis (0/6), although statistical significance was not reached (P = .06). At high‐dose tPA, vepoloxamer had no additional effects on clot lysis (5/6 [83% ] vs 4/6 [66%]). Conclusions Vepoloxamer alone modestly increased bleeding time. Vepoloxamer also increased bleeding time in rats treated with low‐dose heparin but not with high‐dose heparin. Vepoloxamer potentiated clot lysis in the setting of low‐dose tPA. Clinical Relevance Vepoloxamer has potential as an antithrombotic and thrombolytic adjunct. It may potentiate the effects of heparin and tissue plasminogen activator. As an adjunct, vepoloxamer may improve drug efficacy while decreasing adverse effects and cost.

Transient atrial fibrillation after open abdominal aortic revascularization surgery is associated with increased length of stay, mortality, and readmission rates

Background: It is well established that transient postoperative atrial fibrillation (TPAF) is associated with adverse postoperative outcomes after major cardiac and noncardiac operations. The purpose of this study was to elucidate the incidence, impact, and risk factors associated with the development of TPAF in patients undergoing revascularization surgery for occlusive diseases of the abdominal aorta and its branches (AAB). Methods: By use of the Healthcare Cost and Utilization Project State Inpatient Database from Florida and California, patients who underwent open revascularization of AAB between 2006 and 2011 were identified. Patients diagnosed with aortic dissection or abdominal aortic aneurysm were excluded to limit the study cohort to include only patients with occlusive etiology. Also excluded were those with a pre‐existing diagnosis of atrial fibrillation and those who underwent thoracic aortic repair and peripheral artery revascularization procedures. Multivariable logistic and linear regression analyses with treatment effects were conducted to analyze the association between TPAF and length of stay (LOS); the mortality rates at index admission, 1 month, and 1 year; and the readmission rates at 1 month and 1 year (adjusted for comorbidities and surgical and demographic factors). A backwards stepwise logistic regression model was built to identify predictors of TPAF. Results: A total of 4462 patients were identified; 3253 underwent aortoiliac/femoral bypasses (72.9%), 1514 endarterectomies of AAB (33.9%), and 288 bypasses of AAB (6.5%). The incidence of TPAF was 2.4% (109 patients). Multivariate regression analysis with treatment effects showed that TPAF was associated with significantly increased LOS, mortality, and readmission rates. Factors identified as predictors of TPAF by backwards stepwise logistic regression modeling include electrolyte disorders, increasing age, and Charlson Comorbidity Index (C statistic = .69; accuracy = 58%). Conclusions: TPAF after revascularization of AAB is associated with increased LOS, inpatient mortality, 1‐year mortality, and hospital readmissions. Strategies to identify patients at risk for development of TPAF and implementation of appropriate prophylactic measures may improve surgical outcomes and reduce cost of care.