Donor Heart Recovery and Preservation Modalities in 2024

Historically, heart transplantation (HT) has relied on the use of traditional cold storage for donor heart preservation. This organ preservation modality has several limitations, including the risk for ischemic and cold-induced graft injuries that may contribute to primary graft dysfunction and poor post-HT outcomes. In recent years, several novel donor heart preservation modalities have entered clinical practice, including the SherpaPak Cardiac Transport System of controlled hypothermic preservation, and the Transmedics Organ Care System of ex vivo perfusion. Such technologies are altering the landscape of HT by expanding the geographic reach of procurement teams and enabling both donation after cardiac death and the use of expanded criteria donor hearts. This paper will review the emerging evidence on the association of these modalities with improved post-HT outcomes, and will also suggest best practices for selecting between donor heart preservation techniques.

Pathophysiology and management of valvular disease in patients with destination left ventricular assist devices

Over the last two decades, implantable continuous flow left ventricular assist devices (LVAD) have proven to be invaluable tools for the management of selected advanced heart failure patients, improving patient longevity and quality of life. The presence of concomitant valvular pathology, including that involving the tricuspid, mitral, and aortic valve, has important implications relating to the decision to move forward with LVAD implantation. Furthermore, the presence of concomitant valvular pathology often influences the surgical strategy for LVAD implantation. Concomitant valve repair or replacement is not uncommonly required in such circumstances, which increases surgical complexity and has demonstrated prognostic implications both short and longer term following LVAD implantation. Beyond the index operation, it is also well established that certain valvular pathologies may develop or worsen over time following LVAD support. The presence of pre-existing valvular pathology or that which develops following LVAD implant is of particular importance to the destination therapy LVAD patient population. As these patients are not expected to have the opportunity for heart transplantation in the future, optimization of LVAD support including ameliorating valvular disease is critical for the maximization of patient longevity and quality of life. As collective experience has grown over time, the ability of clinicians to effectively address concomitant valvular pathology in LVAD patients has improved in the pre-implant, implant, and post-implant phase, through both medical management and procedural optimization. Nevertheless, there remains uncertainty over many facets of concomitant valvular pathology in advanced heart failure patients, and the understanding of how to best approach these conditions in the LVAD patient population continues to evolve. Herein, we present a comprehensive review of the current state of the field relating to the pathophysiology and management of valvular disease in destination LVAD patients.

Right heart failure after left ventricular assist device: From mechanisms to treatments

Left ventricular assist device (LVAD) therapy is a lifesaving option for patients with medical therapy-refractory advanced heart failure. Depending on the definition, 5-44% of people supported with an LVAD develop right heart failure (RHF), which is associated with worse outcomes. The mechanisms related to RHF include patient, surgical, and hemodynamic factors. Despite significant progress in understanding the roles of these factors and improvements in surgical techniques and LVAD technology, this complication is still a substantial cause of morbidity and mortality among LVAD patients. Additionally, specific medical therapies for this complication still are lacking, leaving cardiac transplantation or supportive management as the only options for LVAD patients who develop RHF. While significant effort has been made to create algorithms aimed at stratifying risk for RHF in patients undergoing LVAD implantation, the predictive value of these algorithms has been limited, especially when attempts at external validation have been undertaken. Perhaps one of the reasons for poor performance in external validation is related to differing definitions of RHF in external cohorts. Additionally, most research in this field has focused on RHF occurring in the early phase (i.e., ≤1 month) post LVAD implantation. However, there is emerging recognition of late-onset RHF (i.e., > 1 month post-surgery) as a significant cause of morbidity and mortality. Late-onset RHF, which likely has a unique physiology and pathogenic mechanisms, remains poorly characterized. In this review of the literature, we will describe the unique right ventricular physiology and changes elicited by LVADs that might cause both early- and late-onset RHF. Finally, we will analyze the currently available treatments for RHF, including mechanical circulatory support options and medical therapies.

The History of Durable Left Ventricular Assist Devices and Comparison of Outcomes: HeartWare, HeartMate II, HeartMate 3, and the Future of Mechanical Circulatory Support

The utilization of left ventricular assist devices (LVADs) in end-stage heart failure has doubled in the past ten years and is bound to continue to increase. Since the first of these devices was approved in 1994, the technology has changed tremendously, and so has the medical and surgical management of these patients. In this review, we discuss the history of LVADs, evaluating survival and complications over time. We also aim to discuss practical aspects of the medical and surgical management of LVAD patients and future directions for outcome improvement in this population.

Does deeper hypothermia reduce the risk of acute kidney injury after circulatory arrest for aortic arch surgery?

OBJECTIVES

The impact of hypothermic circulatory arrest (HCA) temperature on postoperative acute kidney injury (AKI) has not been evaluated. This study examined the association between circulatory arrest temperatures and AKI in patients undergoing proximal aortic surgery with HCA.

METHODS

A total of 759 consecutive patients who underwent proximal aortic surgery (ascending ± valve ± root) including arch replacement requiring HCA between July 2005 and December 2016 were identified from a prospectively maintained institutional aortic surgery database. The primary outcome was AKI as defined by Risk, Injury, Failure, Loss, End Stage Renal Disease (ESRD) criteria. The association between minimum nasopharyngeal (NP) and bladder temperatures during HCA and postoperative AKI was assessed, adjusting for patient-level factors using multivariable logistic regression.

RESULTS

A total of 85% (n = 645) of patients underwent deep hypothermia (14.1-20.0°C), 11% (n = 83) low-moderate hypothermia (20.1-24.0°C) and 4% (n = 31) high-moderate hypothermia (24.1-28.0°C) as classified by NP temperature. When analysed by bladder temperature, 59% (n = 447) underwent deep hypothermia, 22% (n = 170) low-moderate, 16% (n = 118) high-moderate and 3% mild (n = 24) (28.1-34.0°C) hypothermia. The median systemic circulatory arrest time was 17 min. The incidence of AKI did not differ between hypothermia groups, whether analysed using minimum NP or bladder temperature. In the multivariable analysis, the association between degree of hypothermia and AKI remained non-significant whether analysed as a categorical variable (hypothermia group) or as a continuous variable (minimum NP or bladder temperature) (all P > 0.05).

CONCLUSIONS

In patients undergoing proximal aortic surgery including arch replacement requiring HCA, degree of systemic hypothermia was not associated with the risk of AKI. These data suggest that moderate hypothermia does not confer increased risk of AKI for patients requiring circulatory arrest, although additional prospective data are needed.

Adjuvant Chemotherapy Improves Survival Following Resection of Locally Advanced Rectal Cancer with Pathologic Complete Response

BACKGROUND

Controversy exists over the use of adjuvant chemotherapy for locally advanced (stages II-III) rectal cancer (LARC) patients who demonstrate pathologic complete response (pCR) following neoadjuvant chemoradiation. We conducted a retrospective analysis to determine whether adjuvant chemotherapy imparts survival benefit among this population.

METHODS

The National Cancer Database (NCDB) was queried to identify LARC patients with pCR following neoadjuvant chemoradiation. The cohort was stratified by receipt of adjuvant chemotherapy. Multiple imputation and a Cox proportional hazards model were employed to estimate the effect of adjuvant chemotherapy on overall survival.

RESULTS

There were 24,418 patients identified in the NCDB with clinically staged II or III rectal cancer who received neoadjuvant chemoradiation. Of these, 5606 (23.0%) had pCR. Among patients with pCR, 1401 (25%) received adjuvant chemotherapy and 4205 (75%) did not. Patients who received adjuvant chemotherapy were slightly younger, more likely to have private insurance, and more likely to have clinically staged III disease, but did not differ significantly in comparison to patients who did not receive adjuvant chemotherapy with respect to race, sex, facility type, Charlson comorbidity score, histologic tumor grade, procedure type, length of stay, or rate of 30-day readmission following surgery. On adjusted analysis, receipt of adjuvant chemotherapy was associated with a lower risk of death at a given time compared to patients who did not receive adjuvant chemotherapy (HR 0.808; 95% CI 0.679-0.961; p = 0.016).

CONCLUSION

Supporting existing NCCN guidelines, the findings from this study suggest that adjuvant chemotherapy improves survival for LARC with pCR following neoadjuvant chemoradiation.

Successful aneurysm resection and coronary artery revascularization following saphenous vein graft aneurysm rupture

Saphenous vein graft aneurysms after coronary artery bypass grafting (CABG) have been rarely reported. Their incidence and natural history are poorly defined. Herein, we present a patient who presented acutely with contained rupture of a large saphenous vein graft aneurysm 12 years after CABG, which was successfully managed with open aneurysm resection and regrafting.

Mitochondrial quality-control dysregulation in conditional HO-1-/- mice

The heme oxygenase-1 (Hmox1; HO-1) pathway was tested for defense of mitochondrial quality control in cardiomyocyte-specific Hmox1 KO mice (HO-1[CM]^-/-) exposed to oxidative stress (100% O₂). After 48 hours of exposure, these mice showed persistent cardiac inflammation and oxidative tissue damage that caused sarcomeric disruption, cardiomyocyte death, left ventricular dysfunction, and cardiomyopathy, while control hearts showed minimal damage. After hyperoxia, HO-1(CM)^-/- hearts showed suppression of the Pgc-1α/nuclear respiratory factor-1 (NRF-1) axis, swelling, low electron density mitochondria by electron microscopy (EM), increased cell death, and extensive collagen deposition. The damage mechanism involves structurally deficient autophagy/mitophagy, impaired LC3II processing, and failure to upregulate Pink1- and Park2-mediated mitophagy. The mitophagy pathway was suppressed through loss of NRF-1 binding to proximal promoter sites on both genes. These results indicate that cardiac Hmox1 induction not only prevents heme toxicity, but also regulates the timing and registration of genetic programs for mitochondrial quality control that limit cell death, pathological remodeling, and cardiac fibrosis.

Neurophysiological Intraoperative Monitoring During Aortic Arch Surgery

Circulatory management during replacement of the aortic arch is complex and involves a period of circulatory arrest to provide a bloodless field during arch vessel anastomosis. To guard against ischemic brain injury, tissue metabolic demand is reduced by systemically cooling the patient prior to circulatory arrest. Neurophysiological intraoperative monitoring (NIOM) is often used during the course of these procedures to provide contemporaneous assessment of brain status to help direct circulatory management decisions and detect brain ischemia. In this review, we discuss the characteristics of electrocerebral activity through the process of cooling, circulatory arrest, and rewarming as depicted through commonly used NIOM modalities, including electroencephalography and peripheral nerve somatosensory-evoked potentials. Attention is directed toward the role NIOM has traditionally played during deep hypothermic circulatory arrest, where it is used to define the point of electrocerebral inactivity or maximal cerebral metabolic suppression prior to initiating circulatory arrest while also discussing the evolving utility of NIOM when systemic circulatory arrest is initiated at more moderate degrees of hypothermia in conjunction with regional brain perfusion. The use of cerebral tissue oximetry by near-infrared spectroscopy as an alternative NIOM modality during surgery of the aortic arch is addressed as well. Finally, special considerations for NIOM and the detection of spinal cord ischemia during hybrid aortic arch repair and emerging operative techniques are also discussed.

Complementary roles of open and hybrid approaches to thoracoabdominal aortic aneurysm repair

OBJECTIVE

Thoracoabdominal aortic aneurysm (TAAA) repair remains a significant challenge with considerable perioperative morbidity and mortality. A hybrid approach utilizing visceral debranching with endovascular aneurysm exclusion has been used to treat high-risk patients and therefore allow repair in more patients. Limited data exist regarding long-term outcomes with this procedure as well as comparison to conventional open repair. This study describes our institutional algorithmic approach to TAAA repair using both open and hybrid techniques.

METHODS

Hybrid and open TAAA repairs performed between July 2005 and August 2015 were identified from a prospectively maintained institutional aortic surgery database. Perioperative morbidity and mortality, freedom from reintervention, and long-term and aorta-specific survival were calculated and compared between the two groups.

RESULTS

During the study period, 165 consecutive TAAA repairs were performed, including 84 open repairs and 81 hybrid repairs. Patients in the hybrid repair group were significantly older, were more frequently female, and had a generally greater comorbid disease burden, including significantly more chronic kidney disease. Despite the older and sicker cohort, there was no difference in in-hospital mortality between the two groups (9.9% hybrid vs 7.1% open; P = .59). Major morbidity rates differed by procedure, with patients undergoing open repair having a significantly higher rate of postoperative stroke (9.5% open vs 0% hybrid; P = .017), whereas patients undergoing hybrid repair had a higher rate of new permanent dialysis (14.8% hybrid vs 3.6% open; P = .043). There was no difference between groups in the rate of postoperative permanent paraplegia/paresis (8.3% open vs 7.4% hybrid; P = .294). There was a significantly increased rate of reintervention in the hybrid repair group (12.3% hybrid vs 1.2% open, P = .004), with all hybrid reinterventions performed because of endoleak. One-year survival was similar between groups at 69% in hybrid repairs vs 77% in open repairs. Long-term survival was worse in the hybrid group (5-year survival, 32% hybrid vs 56% open), although late survival appeared to be influenced mainly by comorbid disease burden, given the similar long-term aorta-specific survival between groups.

CONCLUSIONS

Use of an algorithmic approach whereby higher risk patients with TAAA are treated by a hybrid approach and lower risk patients with conventional open repair yields satisfactory short- and long-term outcomes. The availability of multiple options for TAAA repair within a single center likely allows repair in more patients with consequent decrease in the risk of aorta-related death, at the expense of increased reinterventions for endoleak.

Evolving practice pattern changes and outcomes in the era of hybrid aortic arch repair

OBJECTIVE

The role of hybrid repair in the management of aortic arch pathology, and long-term outcomes with these techniques, remains uncertain. We report a decade of experience with hybrid arch repair (HAR) and assess institutional practice patterns with regard to the use of hybrid and open techniques.

METHODS

Hybrid and open total and distal arch procedures performed between July 2005 and January 2015 were identified from a prospectively maintained, institutional aortic surgery database. Perioperative morbidity and mortality, freedom from reintervention, and long-term survival were calculated. Hybrid and open procedural volumes over the study period were assessed to evaluate for potential practice pattern changes.

RESULTS

During the study period 148 consecutive procedures were performed for repair of transverse and distal aortic arch pathology, including 101 hybrid repairs and 47 open total or distal arch repairs. Patients in the hybrid repair group were significantly older with a greater incidence of chronic kidney disease, peripheral vascular disease, and chronic lung disease. Perioperative mortality and outcomes were not significantly different between the hybrid and open groups, aside from decreased median length of stay after hybrid repair. Need for subsequent reintervention was significantly greater after hybrid repair. Unadjusted long-term survival was superior after open repair (70% 5-year survival open vs 47% hybrid; P = .03), although aorta-specific survival was similar (98% 5-year aorta-specific survival open vs 93% hybrid; P = .59). Institutional use of HAR decreased over the final 3 years of the study, with an associated increased use of open total or distal arch repairs. This was primarily the result of decreased use of native zone 0 hybrid procedures. Concurrent with this apparent increased stringency around patient selection for HAR, perioperative morbidity and mortality was reduced, including avoidance of retrograde type A dissection.

CONCLUSIONS

HAR remains a viable option for higher-risk patients with transverse arch pathology with perioperative outcomes and long-term aorta-specific survival similar to open repair, albeit at a cost of increased reintervention. This observational single-institution study would suggest decreased use in more recent years in favor of open repair due to avoidance of native zone 0 hybrid procedures. This decline in the institutional use of native zone 0 hybrid repairs was associated with improved perioperative outcomes.

Use of human fibrinogen concentrate during proximal aortic reconstruction with deep hypothermic circulatory arrest

OBJECTIVE

Human fibrinogen concentrate (HFC) is approved by the Food and Drug Administration for use at 70 mg/kg to treat congenital afibrinogenemia. We sought to determine whether this dose of HFC increases fibrinogen levels in the setting of high-risk bleeding associated with aortic reconstruction and deep hypothermic circulatory arrest (DHCA).

METHODS

This was a prospective, pilot, off-label study in which 22 patients undergoing elective proximal aortic reconstruction with DHCA were administered 70 mg/kg HFC upon separation from cardiopulmonary bypass (CPB). Fibrinogen levels were measured at baseline, just before, and 10 minutes after HFC administration, on skin closure, and the day after surgery. The primary study outcome was the difference in fibrinogen level immediately after separation from CPB, when HFC was administered, and the fibrinogen level 10 minutes following HFC administration. Additionally, postoperative thromboembolic events were assessed as a safety analysis.

RESULTS

The mean baseline fibrinogen level was 317 ± 49 mg/dL and fell to 235 ± 39 mg/dL just before separation from CPB. After HFC administration, the fibrinogen level rose to 331 ± 41 mg/dL (P < .001) and averaged 372 ± 45 mg/dL the next day. No postoperative thromboembolic complications occurred.

CONCLUSIONS

Administration of 70 mg/kg HFC upon separation from CPB raises fibrinogen levels by approximately 100 mg/dL without an apparent increase in thrombotic complications during proximal aortic reconstruction with DHCA. Further prospective study in a larger cohort of patients will be needed to definitively determine the safety and evaluate the efficacy of HFC as a hemostatic adjunct during these procedures.

Comparison of aortic annulus size by transesophageal echocardiography and computed tomography angiography with direct surgical measurement

This study sought to compare the accuracy of 2-dimensional transesophageal echocardiography (TEE) and computed tomography angiography (CTA) for noninvasive aortic annular sizing as required for transcatheter aortic valve implantation (TAVI). Direct intraoperative (OR) sizing is the gold standard for aortic annular measurement in surgical aortic valve replacement. Unlike surgical aortic valve replacement, TAVI requires noninvasive assessment of aortic annular dimensions for determining the size of prosthesis to be implanted and controversy exists regarding the best imaging technique for TAVI sizing. Preoperative CTA and OR TEE images of the aortic annulus in 227 patients who underwent proximal aortic surgery with OR annular sizing at the Duke University Medical Center were reviewed. Both imaging techniques were compared with direct OR measurements of aortic annulus diameter using metric sizers as the gold standard. CTA overestimated aortic annulus diameter in 72.2% of cases, with 46.3% >1 TAVI valve-size (>3 mm) overestimations, whereas TEE underestimated aortic annulus diameter in 51.1% of cases, with 16.7% >1 valve-size underestimations. Combining both techniques improved the estimation of aortic annular size. In conclusion, there are limitations to current imaging techniques for noninvasive determination of aortic annular dimensions compared with direct OR sizing. Undersizing by TEE and oversizing by CTA are common and may be related to differences in methods for sizing an elliptical structure. Combining measurements from both techniques would decrease the false exclusion rate for TAVI eligibility because of size mismatch.

Improving Outcomes in Colorectal Surgery by Sequential Implementation of Multiple Standardized Care Programs

BACKGROUND

The purpose of this study was to examine the impact of the sequential implementation of the enhanced recovery program (ERP) and surgical site infection bundle (SSIB) on short-term outcomes in colorectal surgery (CRS) to determine if the presence of multiple standardized care programs provides additive benefit.

STUDY DESIGN

Institutional ACS-NSQIP data were used to identify patients who underwent elective CRS from September 2006 to March 2013. The cohort was stratified into 3 groups relative to implementation of the ERP (February 1, 2010) and SSIB (July 1, 2011). Unadjusted characteristics and 30-day outcomes were assessed, and inverse proportional weighting was then used to determine the adjusted effect of these programs.

RESULTS

There were 787 patients included: 337, 165, and 285 in the pre-ERP/SSIB, post-ERP/pre-SSIB, and post-ERP/SSIB periods, respectively. After inverse probability weighting (IPW) adjustment, groups were balanced with respect to patient and procedural characteristics considered. Compared with the pre-ERP/SSIB group, the post-ERP/pre-SSIB group had significantly reduced length of hospitalization (8.3 vs 6.6 days, p = 0.01) but did not differ with respect to postoperative wound complications and sepsis. Subsequent introduction of the SSIB then resulted in a significant decrease in superficial SSI (16.1% vs 6.3%, p < 0.01) and postoperative sepsis (11.2% vs 1.8%, p < 0.01). Finally, inflation-adjusted mean hospital cost for a CRS admission fell from $31,926 in 2008 to $22,044 in 2013 (p < 0.01).

CONCLUSIONS

Sequential implementation of the ERP and SSIB provided incremental improvements in CRS outcomes while controlling hospital costs, supporting their combined use as an effective strategy toward improving the quality of patient care.

Optimal timing of tracheostomy after trauma without associated head injury

BACKGROUND

Controversy exists over optimal timing of tracheostomy in patients with respiratory failure after blunt trauma. The study aimed to determine whether the timing of tracheostomy affects mortality in this population.

METHODS

The 2008-2011 National Trauma Data Bank was queried to identify blunt trauma patients without concomitant head injury who required tracheostomy for respiratory failure between hospital days 4 and 21. Restricted cubic spline analysis was performed to evaluate the relationship between tracheostomy timing and the odds of inhospital mortality. The cohort was stratified based on this analysis. Unadjusted characteristics and outcomes were compared. Multivariable logistic regression was used to evaluate the effect of tracheostomy timing on mortality after adjustment for age, gender, race, payor status, level of trauma center, injury severity score, presentation Glasgow coma scale, and thoracic and abdominal abbreviated injury score.

RESULTS

There were 9662 patients included in the study. Restricted cubic spline analysis demonstrated a nonlinear relationship between timing of tracheostomy and mortality, with higher odds of mortality occurring with tracheostomy placement within 10 d of admission compared with later time points. The cohort was therefore stratified into early and delayed tracheostomy groups relative to this time point. The resulting groups contained 5402 (55.9%) and 4260 (44.1%) patients, respectively. After multivariable adjustment, the delayed tracheostomy group continued to have significantly reduced odds of mortality (Adjusted odds ratio, 0.82, 95% confidence interval, 0.71-0.95, C-statistic, 0.700).

CONCLUSIONS

Among non-head injured blunt trauma patients with prolonged respiratory failure, tracheostomy placement within 10 d of admission may result in increased mortality compared with later time points.

Management of 1- to 2-cm Carcinoid Tumors of the Appendix: Using the National Cancer Data Base to Address Controversies in General Surgery

BACKGROUND

The management of 1- to 2-cm appendiceal carcinoid tumors remains controversial. Here we use the National Cancer Data Base (NCDB) to compare long-term outcomes for patients treated via resection of the primary tumor alone vs right hemicolectomy (RHC).

STUDY DESIGN

The 1998 to 2011 NCDB User File was queried to identify patients with 1- to 2-cm appendiceal carcinoids. Patients were stratified by surgical technique: resection of the primary tumor alone vs RHC with regional lymphadenectomy. Multivariable logistic regression was used to compare short-term outcomes. Survival was estimated using the Kaplan-Meier method with comparisons based on the log-rank test.

RESULTS

A total of 916 patients were identified, including 42% managed with primary resection and 58% with RHC. Patients who underwent RHC had slightly larger tumors and higher-stage tumors; otherwise, there were no baseline differences between groups. The rates of positive margins were similar (5.5% vs 4.5%; p = 0.60). Among all patients, 1- and 5-year survival were 98.1% and 88.7% vs 96.7% and 87.4% (p = 0.52) for those managed via primary resection vs RHC, respectively. Among patients with moderate/high-grade/anaplastic carcinoids, 1- and 5-year survival were 93.3% and 72.0% vs 92.3% and 71.9%, respectively (p = 0.78). After adjustment with Cox proportional hazards modeling, we confirmed that there was no survival benefit for patients undergoing RHC (hazard ratio = 1.14; p = 0.72).

CONCLUSIONS

For 1- to 2-cm appendiceal carcinoids, formal resection of the right colon does not appear to improve survival, even for higher-grade tumors. Our findings suggest that resection of the primary tumor alone is adequate for all carcinoids <2 cm.

Laparoscopic versus open low anterior resection for rectal cancer: results from the national cancer data base

BACKGROUND

While the use of laparoscopy has increased among patients undergoing colorectal surgery, there is ongoing debate regarding the oncologic equivalence of laparoscopy compared to open low anterior resection (LAR) for rectal cancer.

METHODS

The 2010-2011 NCDB was queried for patients undergoing LAR for rectal cancer. Subjects were grouped by laparoscopic (LLAR) versus open (OLAR) technique. Baseline characteristics were compared. Subjects were propensity matched, and outcomes were compared between groups.

RESULTS

A total of 18,765 patients were identified (34.3% LLAR, 65.7% OLAR). After propensity matching, all baseline variables were highly similar except for carcinoembryonic antigen (CEA) level. Complete resection was more common in patients undergoing LLAR (91.6 vs. 88.9%, p < 0.001), and statistically significant benefits were observed for gross, microscopic, and circumferential (>1 mm) margins (all p < 0.001). There was no difference in median number of lymph nodes obtained (15 vs. 15). Patients undergoing LLAR had shorter lengths of stay (5 vs. 6 days, p < 0.001) without a corresponding increase in 30-day readmission rates (6 vs. 7%, p = 0.02).

CONCLUSIONS

Laparoscopic LAR appears to result in equivalent short-term oncologic outcomes compared to the traditional open approach as measured via surrogate endpoints in the NCDB. While these results support the increasing use of laparoscopy in rectal surgery, further data are necessary to assess long-term outcomes.

Thoracic endovascular aortic repair for chronic DeBakey IIIb aortic dissection

BACKGROUND

Thoracic endovascular aortic repair (TEVAR) for chronic DeBakey IIIb dissection with associated descending aneurysm remains controversial. This study examines long-term results of TEVAR for this disorder including examination of anatomic features associated with TEVAR outcomes.

METHODS

Between July 2005 and January 2013, 32 patients underwent TEVAR for chronic (>30 days) DeBakey IIIb dissection involving the descending thoracic aorta at a single institution and constituted the study cohort.

RESULTS

The mean interval from dissection to TEVAR was 32 ± 44 months (range, 1 to 146 months). There were no 30-day or in-hospital deaths, strokes, or paraplegia. During a 54-month median follow-up, there were no aortic-related deaths. Significant thoracic aneurysm sac regression (>1 cm) in the intervened segment was observed in 89%. Thoracic remodeling was not correlated with the number of visceral vessels arising from the true lumen or the number or size of residual distal fenestrations; failure of thoracic remodeling was associated with fenestrations distal to the endograft(s) in the descending thoracic aorta, most often stent graft-induced new entry tears. Complete resolution of the thoracic and abdominal false lumen after TEVAR was observed in 15.6% (n = 5). All patients in this group had all visceral vessels arising from the true lumen and fewer than three residual distal fenestrations.

CONCLUSIONS

Thoracic endovascular aortic repair is effective for chronic DeBakey IIIb dissection with associated descending aneurysm, with excellent 30-day and long-term outcomes and significant aortic remodeling in the vast majority of patients. Thoracic remodeling does not appear dependent on distal anatomic characteristics of the true and false lumens, although care should be taken to cover all thoracic fenestrations and avoid creation of stent graft-induced new entry tears to ensure clinical success. Complete aortic remodeling was observed only in the setting of all visceral vessels off the true lumen with fewer than three residual distal fenestrations, and this would appear the ideal anatomy for TEVAR in this scenario.

The effect of neoadjuvant radiation therapy on perioperative outcomes among patients undergoing resection of retroperitoneal sarcomas

BACKGROUND

Neoadjuvant radiation therapy (RT) has several theoretical benefits in the treatment of retroperitoneal sarcoma (RPS), but concerns remain about treatment toxicity and perioperative morbidity. There are limited data regarding its effect on perioperative outcomes, most of which come from small, single-institution series. The purpose of this study was to evaluate the short-term (30-day) postoperative morbidity and mortality associated with neoadjuvant RT following resection of RPS.

METHODS

The 2005-2011 National Surgical Quality Improvement Program Participant User File was queried for patients undergoing RPS resection. Subjects were stratified by use of neoadjuvant RT. Perioperative variables and short-term 30-day outcomes were compared. Groups were then propensity matched using a 2:1 nearest-neighbor algorithm and multivariable logistic regression was performed to assess neoadjuvant RT as a predictor of short-term 30-day outcomes.

RESULTS

A total of 785 patients were identified. Neoadjuvant RT was administered to 71 (9.0%). Patients who received neoadjuvant RT were slightly younger (56 vs. 62 years, p < 0.001), but otherwise the groups were similar. After propensity matching, all baseline characteristics were highly similar. Median operative time was longer in the neoadjuvant RT group (279 vs. 219 min, p < 0.01), but there were no differences in mortality (1.4 vs. 2.1%, p = 0.71), major complications (28.2 vs. 25.2%, p = 0.69), overall complications (35.2 vs.33.2%, p = 0.83), early reoperation (5.6 vs. 7.4%, p = 0.81), or length of stay (7 vs. 7 days, p = 0.56). Following further adjustment with logistic regression, we confirmed that there were no differences in 30-day mortality or morbidity between patients who did and did not receive neoadjuvant RT.

CONCLUSIONS

Neoadjuvant RT does not appear to increase short-term (30-day) morbidity or mortality following resection of RPS. Continued investigation is needed to better define the role for radiation therapy among patients with this disease.

Abstract 86: Cardiomyocyte-Specific Ablation of Nuclear Respiratory Factor 1 in the Mouse Leads to Dysregulation of Mitochondrial Biogenesis, Apoptosis, and Heart Failure

The DNA-binding transcription factor Nuclear Respiratory Factor 1 (NRF1) regulates mitochondrial homeostasis. Its constitutive ablation in the mouse is embryonically lethal (~E3.5). This has limited our understanding of NRF1 functionality in the heart, where mitochondrial dysfunction is often a major pathogenic factor. Therefore, we generated conditional cardiomyocyte-specific NRF1 knockout mice (MYH6-mer-Cre-mer-NRF1fl/fl or NRFfl/fl) to elucidate the role of cardiac NRF1. Two weeks after NRF1 silencing, echocardiography of NRF1fl/fl hearts revealed significant reductions in left ventricular fractional shortening (Figure A). Histology demonstrated degradation of cellular structural integrity and nuclear condensation (Figure B), with a high number of TUNEL positive nuclei compared to littermate controls (MYH6-mer-Cre-mer-NRF-1wt), indicative of apoptosis (37.8% vs. 1.1%, p < 0.001). The mRNA and protein levels of key mediators of mitochondrial biogenesis were evaluated by real-time RT-PCR and immunoblotting (Figure C & D). Compared to littermate controls, there was down-regulation of the mitochondrial encoded NADH dehydrogenase 1, implying a reduction of functional mitochondrial mass. Key biogenesis regulators PGC1-α (protein only), Nfe2l2, and NRF2 were also reduced. In total, these data support that dysregulation of mitochondrial biogenesis after loss of NRF1 results in cardiomyocyte apoptosis and reduced left ventricular function. These findings and further delineation of the mechanisms involved should lay the foundation for the exploitation of NRF1 as a therapeutic target in heart failure.

Current management and outcome of chronic type B aortic dissection: results with open and endovascular repair since the advent of thoracic endografting

BACKGROUND

Thoracic endovascular aortic repair (TEVAR) has become the preferred treatment for chronic type B aortic dissection (CTBAD) at our institution. However, it remains incapable of treating all patients with CTBAD. The present study aims to review our contemporary results with open and endovascular CTBAD repairs since the advent of thoracic endografting.

METHODS

The records of all patients undergoing index repair of CTBAD (chronic DeBakey type IIIA, IIIB and repaired type I) at our institution between June 2005 and December 2013, were retrospectively reviewed.

RESULTS

A total of 107 patients underwent CTBAD repair, of whom 70% (n=75) underwent endovascular-based procedures [44 TEVAR, 27 hybrid arch and four hybrid thoracoabdominal aortic aneurysm (TAAA) repair] and 30% (n=32) underwent open procedures (nine open descending and 23 open TAAA). Connective tissue disease (CTD), prior aortic surgery and DeBakey dissection type were strongly associated with the choice of operation. The rates of stroke, paraplegia and operative mortality following endovascular-based repairs were 0%, 0% and 4% (n=3), respectively. Adverse neurologic events were higher following open repair, and rates of stroke, paraplegia, and operative mortality were 16% (n=5), 9% (n=3), and 6% (n=2), respectively. However, 1- and 5-year survival rates were similar for endovascular-based repairs (86% and 65%, respectively), and open repairs (88% and 79%, respectively). Over a median follow-up interval of 34 months, the rate of descending aortic reintervention was 24% (n=18) following endovascular-based repairs and 0% following open repairs (P=0.001). Forty-four percent (n=8) of descending aortic reinterventions were required to treat stent graft complications (five endoleak, two stent graft collapse and one stent graft-induced new entry tear) and the remainder were required to treat metachronous pathology (n=2) or progressive aneurysmal disease related to persistent distal fenestrations (n=8).

CONCLUSIONS

Endovascular repair of CTBAD was associated with excellent procedural and survival outcomes, but at the expense of further reinterventions. Open repair remains relevant for patients who are not candidates for endovascular repair and was associated with higher procedural morbidity but similar overall survival and fewer reinterventions.

A novel mutation in NFKBIA/IKBA results in a degradation-resistant N-truncated protein and is associated with ectodermal dysplasia with immunodeficiency

Alterations in nuclear factor kappa B (NF-kappaB) essential modulator (NEMO; HUGO-approved symbol IKBKG) underlie most cases of ectodermal dysplasia with immune deficiency (EDI), a human disorder characterized by anhidrosis with diminished immunity. EDI has also been associated with a single heterozygous mutation at position Ser32 of the NF-kappaB inhibitor IkappaBalpha, one of two phosphorylation sites that are essential for targeting IkappaBalpha for proteasomal degradation and hence for activation of NF-kappaB. We report a novel heterozygous nonsense mutation in the IKBA (HUGO-approved symbol, NFKBIA) gene of a 1-year-old male child with EDI that introduces a premature termination codon at position Glu14. An in-frame methionine downstream of the nonsense mutation allows for reinitiation of translation. The resulting N-terminally truncated protein lacks both serine phosphorylation sites and inhibits NF-kappaB signaling by functioning as a dominant negative on NF-kappaB activity in lymphocytes and monocytes. These findings support the scanning model for translation initiation in eukaryotes and confirm the critical role of the NF-kappaB in the human immune response.

Crystal structure of the cofactor-binding domain of the human phase II drug-metabolism enzyme UDP-glucuronosyltransferase 2B7

Human UDP-glucuronosyltransferases (UGT) are the dominant phase II conjugative drug metabolism enzymes that also play a central role in processing a range of endobiotic compounds. UGTs catalyze the covalent addition of glucuronic acid sugar moieties to a host of therapeutics and environmental toxins, as well as to a variety of endogenous steroids and other signaling molecules. We report the 1.8-A resolution apo crystal structure of the UDP-glucuronic acid binding domain of human UGT isoform 2B7 (UGT2B7), which catalyzes the conjugative elimination of opioid, antiviral, and anticancer drugs. This is the first crystal structure of any region of a mammalian UGT drug metabolism enzyme. Designated UGT2B7 mutants at residues predicted to interact with the UDP-glucuronic acid cofactor exhibited significantly impaired catalytic activity, with maximum effects observed for amino acids closest to the glucuronic acid sugar transferred to the acceptor molecule. Homology modeling of UGT2B7 with related plant flavonoid glucosyltransferases indicates human UGTs share a common catalytic mechanism. Point mutations at predicted catalytic residues in UGT2B7 abrogated activity, strongly suggesting human UGTs also utilize a serine hydrolase-like catalytic mechanism to facilitate glucuronic acid transfer.

The Western Neuro Sensory Stimulation Profile: a tool for assessing slow-to-recover head-injured patients

The Western Neuro Sensory Stimulation Profile (WNSSP) was developed to assess cognitive function in severely impaired head-injured adults (Rancho levels II-V) and to monitor and predict change in slow-to-recover patients. Slow-to-recover patients are those who remain at Rancho levels II and III for extended periods of time and are candidates for sensory stimulation programs. Although sensory stimulation is considered beneficial, its utility has not been documented, partly because of the absence of formal measurement tools. The WNSSP consists of 32 items which assess patients' arousal/attention, expressive communication, and response to auditory, visual, tactile, and olfactory stimulation. It was administered to 57 patients with a mean age of 29 years at a mean time of eight months after injury. Statistical analyses indicate the WNSSP to be a reliable, valid measure of cognitive function. WNSSP means differ at each Rancho level, and ranges of scores at each level are sufficiently broad to demonstrate improvement within as well as across cognitive levels. Subjects who later improved performed significantly better on initial testing than did those who did not improve, suggesting prognostic ability of the WNSSP. Our data support other investigations which emphasize that some slow-to-recover patients experience significant improvement. The WNSSP can be a useful tool for studying the recovery process and evaluating treatment programs for slow-to-recover patients.