Comparing post-maturation outcomes of arteriovenous grafts and fistulae

BACKGROUND

Though arteriovenous grafts (AVG) mature more reliably than arteriovenous fistulae (AVF) and require fewer maturation procedures (MP) to obtain functional patency, AVG are thought to have worse function after maturation. We explored differences in post-maturation outcomes between the following groups: AVF patients who did (AS-AVF) and did not (unAS-AVF) require assisted maturation and AVG patients who did (AS-AVG) and did not (unAS-AVG) require assisted maturation.

METHODS

Using the US Renal Data System (2012-2017), we retrospectively identified patients who initiated dialysis with a central venous catheter, underwent AVF or AVG placement and achieved successful two-needle cannulation. Primary patency and access abandonment after maturation were compared across groups using competing risks regression methods, generating sub-hazards ratios (sHR).

RESULTS

We identified 42,664 AVF and 12,335 AVG that met inclusion criteria. A larger proportion of AVFs required interventions: 18,408 AVF (43.2%) versus 2594 AVG (21.0%; p < 0.01). Both AS-AVG and AS-AVF patients experienced patency loss at 1 year more frequently compared with unAS-AVG (67.5% & 57.5% vs 55.2% respectively). Patency loss was lowest in unAS-AVF (38.9%). These trends were robust on adjusted analysis (unAS-AVG reference, AS-AVG sHR = 1.44, p < 0.01; AS-AVF sHR = 1.08, p < 0.01, unAS-AVF sHR = 0.67, p < 0.01). AS-AVGs were more likely to be abandoned than unAS-AVGs (11.7% unAS-AVG vs 17.2% AS-AVG). Fistulae, assisted or not, had lower unadjusted rates of 1-year abandonment than grafts (8.9% AS-AVF vs 7.3% unAS-AVF). On adjusted analysis, AVF usage was protective against abandonment (unAS-AVG, reference; AS-AVF sHR = 0.67, p < 0.01; unAS-AVF sHR = 0.59, p < 0.01) while AS-AVG was not (AS-AVG sHR = 1.32, p < 0.01).

CONCLUSIONS

unAS-AVF have the best long-term outcomes. AS-AVF lose primary patency at a higher rate than unAS-AVG. AVGs may be a better choice than AVFs if veins are marginal and likely to require assisted maturation. Further research is needed to identify anatomic and physiologic factors that affect long-term performance and influence conduit choice.

Carotid Endarterectomy Should Not Be Recommended to End-Stage Kidney Disease Patients with Asymptomatic Carotid Artery Disease

BACKGROUND

Carotid endarterectomy (CEA) for asymptomatic carotid artery disease is advised for patients with low perioperative stroke risk and life expectancy of 3-5 years. We sought to explore the role of risk stratification and postoperative medical management in identifying appropriate asymptomatic candidates for CEA in the end-stage kidney disease (ESKD) population.

METHODS

We identified ESKD patients on dialysis from the United States Renal Data System that underwent CEA (2008-2014) for asymptomatic carotid artery disease. We used the Liu comorbidity index as well as a novel risk prediction model based on Cox proportional hazards model to stratify patients. The primary outcome evaluated was 3-year survival, and Kaplan-Meier methods were used to generate survival estimates. We further conducted a subanalysis of patients with Medicare part D data to determine postoperative usage of the following medications: statins, antiplatelets, and antihypertensives. We evaluated the association of medication utilization and 3-year survival using Kaplan-Meier methods and Cox proportional hazards modeling.

RESULTS

We analyzed 1,813 patients meeting inclusion criteria. The population was predominantly older (mean age 70.2 ± 9.1), White (84.8%), and had a high prevalence of cardiovascular comorbidities, such as hypertension (90.7%), diabetes (62.5%), and congestive heart failure (35.4%). Among the entire cohort, 23.0% had a Liu comorbidity index ≤8, 35.0% had index 9-12, and 42.0% had index >12. Increasing Liu comorbidity index was associated with worse survival (P < 0.01); however, even the group with Liu index ≤8 had poor 3-year survival of 58.8% (53.9-63.4). The Cox proportional hazards model identified variables for inclusion in the risk model such as age >80 (adjusted hazard ratio [aHR] = 2.49, 95% confidence interval [CI] [1.87-3.33], P < 0.001), congestive heart failure (aHR = 1.31, 95% CI [1.14-1.51], P < 0.001), and Liu comorbidity index >12(aHR = 1.89, 95% CI [1.56-2.28], P < 0.001). The risk score generated ranged from 0 to 6.5, and patients were divided into 3 groups: score ≤2 (43.4%), 2-4 (41.2%), and >4 (15.4%). Increasing risk score was associated with worse survival (P < 0.01) but even the "low-risk" group had 3-year survival of 58.5% (54.9-61.9). Subanalysis of the 1,249 (68.8% of total) patients with part D data found that statins and calcium channel blocker use was associated with improved survival, although observed rates for patients on drug were still low.

CONCLUSIONS

The overall long-term survival of ESKD patients undergoing CEA for asymptomatic carotid artery disease is low. Risk stratification and analysis of postoperative medical management did not identify a subgroup of patients with adequate 3-year survival. Hence, the preventive benefits of CEA are not realized in these patients.

The Role of Integrated Air Transport System in Managing Abdominal Aortic Aneurysm Rupture Patients

OBJECTIVE

Ruptured abdominal aortic aneurysms (rAAAs) are highly morbid emergencies. Not all hospitals are equipped to repair them, and an air ambulance network may aid in regionalising speciality care to quaternary referral centres. The association of travel distance by air ambulance on rAAA mortality in patients transferred emergently for repair was examined.

METHODS

A retrospective review of institutional data. Adults with rAAA (2002 - 2019) transferred from an outside hospital (OSH) to a single quaternary referral centre for repair via air ambulance were identified. Patients who arrived via ground transport or post-repair at OSH for continued critical care were excluded. Patients were divided into "near" and "far" groups based on the 75th percentile of straight line travel distance (> 72 miles) between hospitals. The primary outcome was 30 day mortality. Multivariate logistic regression was used to assess the association of distance with mortality after adjusting for age, sex, race, cardiovascular comorbidities, and repair type.

RESULTS

A total of 290 patients with rAAA were transported a median distance of 40.4 miles (interquartile range 25.5, 72.7) with 215 (74.1%) near and 75 (25.9%) far patients. Both near and far groups had similar ages, sex, and race. There was no difference in pre-operative loss of consciousness, intubation, or cardiac arrest between groups. Endovascular aneurysm repair utilisation and intra-operative aortic occlusion balloon usage were also similar. Both observed (26.8% vs. 23.9%, p = .61) and adjusted odd ratio (0.70, 95% confidence interval 0.36 - 1.39, p = .32) 30 day mortality did not differ significantly between near and far groups.

CONCLUSION

Increasing distance travelled during transfer by air ambulance was not associated with worse outcomes in patients with rAAA. The findings support the regionalisation of rAAA repair to large quaternary centres via an integrated and robust air ambulance network.

Outcomes of octogenarians receiving aortic repair

OBJECTIVE

Abdominal aortic aneurysm (AAA) repair is recommended for aneurysms greater than 5.5 cm in men and 5 cm in women. Because AAA is more common among the elderly, we sought to evaluate contemporary practices of elective AAA repair and 2-year postoperative outcomes in octogenarians.

METHODS

We identified octogenarians undergoing elective AAA repair in the Vascular Quality Initiative from 2012 to 2019. We included patients undergoing endovascular (EVAR) and open (OAR) aortic repair. Demographics and comorbid conditions were compared between patient groups. Frailty was calculated using previously published methods. Patients with frailty scores above the 75th percentile of the operative cohort were considered high frailty. The primary outcome was 1- and 2-year mortality. Secondary outcomes included postoperative complications. Standard statistical methods were utilized. Cox proportional hazard models were used to identify factors that affect mortality.

RESULTS

The frequency of AAA repair in octogenarians has remained stable. Of all aortic operations, 21.4% were performed on octogenarians; 9735 (23.3% of 41,712) EVAR and 755 (10.3% of 7325) OARs. Among octogenarian patients, 42.0% of EVARs were under size thresholds: 48.3% males ≤5.5 cm diameter and 21.5% females ≤5.0 cm diameter compared with 18.8% OARs: 23.4% males and 10.7% females. Additionally, 25.6% had high frailty scores. Among octogenarians, 1- and 2-year mortality was 9.3% ± 0.3% and 14.8% ± 0.4% for EVAR and 15.2% ± 1.3% and 18.9% ± 1.5% for OAR patients, respectively (P < .01). In-hospital mortality rate was higher after OAR (0.87% EVAR vs 7.55% OAR; P < .01) and differed with frailty (EVAR, low frailty 0.2% vs high frailty 1.7%; OAR, low frailty 2.3% vs high frailty 15.6%). For EVAR, patient factors associated with mortality included heart failure (hazard ratio [HR], 1.15; 95% confidence interval [CI], 1.06-1.25; P = .001) and dialysis (HR, 1.71; 95% CI, 1.13-2.59; P = .012). For OAR, coronary artery disease (HR, 1.55; 95% CI, 0.98-2.44; P = .062) was associated with mortality. Statin use was protective of mortality for all patients (EVAR: HR, 0.68; 95% CI, 0.60-0.78; P < .01): OAR: HR, 0.58; 95% CI, 0.37-0.92; P = .020). Among octogenarians, high frailty was independently associated with 2-year mortality (EVAR: HR, 3.36; 95% CI, 2.62-4.31; P < .01 and OAR: HR, 2.35; 95% CI, 1.09-5.10; P = .030).

CONCLUSIONS

Nationally, a large portion of elective AAA repair in octogenarians is performed below recommended size thresholds, one-quarter of whom are frail with poor long-term 2-year mortality rates. High 2-year mortality following AAA repair in this age group exceeds the published risk of rupture for 5- to 5.5-cm AAA, suggesting that increase in the size threshold of elective repair among octogenarians should be explored.

HLA mismatch is important for 20-year graft survival in kidney transplant patients

BACKGROUND

Human leukocyte antigens (HLA) matching is gradually being omitted from clinical practice in evaluation for renal allograft transplant. While such practices may yield shorter wait times and adequate short-term outcomes, graft longevity in HLA mismatched patients remains unclear. This study aims to demonstrate that HLA matching may still play an important role in long-term graft survival.

METHODS

We identified patients undergoing an index kidney transplant in the United Network for Organ Sharing (UNOS) data from 1990 to 1999, with one-year graft survival. The primary outcome of the analysis was graft survival beyond 10 years. We explored the long-lasting impact of HLA mismatches by landmarking the analysis at established time points.

RESULTS

We identified 76,530 patients receiving renal transplants in the time frame, 23,914 from living donors and 52,616 from deceased donors. On multivariate analysis, more HLA mismatches were associated with worse graft survival beyond 10 years for both living and deceased donor allografts. HLA mismatch continued to remain an essential factor in the long term.

CONCLUSIONS

A greater number of HLA mismatches was associated with progressively worse long-term graft survival for patients. Our analysis reinforces the importance of HLA matching in the preoperative evaluation of renal allografts.

Characterization of multiple organ failure after ruptured abdominal aortic aneurysm repair

BACKGROUND

Multiple organ failure (MOF) is associated with poor outcomes and increased mortality in sepsis and trauma. There are limited data regarding MOF in patients after ruptured abdominal aortic aneurysm (rAAA) repair. We aimed to identify the contemporary prevalence and characteristics of patients with rAAA with MOF.

METHODS

We retrospectively reviewed patients with rAAA who underwent repair (2010-2020) at our multihospital institution. Patients who died within the first 2 days after repair were excluded. MOF was quantified by modified (excluding hepatic system) Denver, Sequential Organ Failure Assessment (SOFA) score, and Multiple Organ Dysfunction Score (MODS) for postoperative days 3 to 5 to determine the prevalence of MOF. MOF was defined as a Denver score of >3, dysfunction in two or more organ systems by SOFA score, or a MODS score of >8. Kaplan-Meier curves and log-rank testing were used to evaluate differences in 30-day mortality between multiple organ failure and patients without MOF. Logistic regression was used to assess predictors of MOF.

RESULTS

Of 370 patients with rAAA, 288 survived past two days (mean age, 73±10.1 years; 76.7% male; 44.1% open repair), and 143 had data for MOF calculation recorded. From postoperative days 3 to 5, 41 (14.24%) had MOF by Denver, 26 (9.03%) by SOFA, and 39 (13.54%) by MODS criteria. Among these scoring systems, pulmonary and neurological systems were impacted most commonly. Among patients with MOF, pulmonary derangement occurred in 65.9% (Denver), 57.7% (SOFA), and 56.4% (MODS). Similarly, neurological derangement occurred in 92.3% (SOFA) and 89.7% (MODS), but renal derangement occurred in 26.8% (Denver), 23.1% (SOFA), and 10.3% (MODS). MOF by all three scoring systems was associated with increased 30-day mortality (Denver: 11.3% vs 41.5% [P < .01]; DOFA: 12.6% vs 46.2% [P < .01]; MODS: 12.5% vs 35.9% [P < .01]), as was MOF by any criteria (10.8% vs 35.7 %; P < .01). Patients with MOF were more likely to have a higher body mass index (55.9±26.6 vs 49.0±15.0; P = .011) and to have had a preoperative stroke (17.9% vs 6.0%; P = .016). Patients with MOF were less likely to have undergone endovascular repair (30.4% vs 62.1%; P < .001). Endovascular repair was protective against MOF (any criteria) on multivariate analysis (odds ratio, 0.23; 95% confidence interval, 0.08-0.64; P = .019) after adjusting for age, gender, and presenting systolic blood pressure.

CONCLUSIONS

MOF occurred in only 9% to 14% of patients after rAAA repair, but was associated with a three-fold increase in mortality. Endovascular repair was associated with a reduced MOF incidence.

Surgical and endovascular assisted maturation procedures improve cannulation after arteriovenous fistula creation, but not after arteriovenous graft placement

OBJECTIVE

After creation, arteriovenous fistulae (AVF) and arteriovenous grafts (AVG) can undergo surgical or endovascular assisted maturation (AM) procedures to enable use for hemodialysis. We sought to explore the association of interventions with successful two-needle cannulation (TNC) using the United States Renal Data System (USRDS).

METHODS

Using the 2012-2017 USRDS, we identified patients initiating hemodialysis with tunneled dialysis catheters (TDC). Successful AVF/G use was defined as two-needle cannulation (TNC). Our principal outcome was time to first TNC after AVF/G creation. Death and new access placement were competing events that precluded TNC. Competing-risks regression models were constructed to identify factors associated with cannulation. Logistic regression was used to assess the association between AM procedures and 1-year TNC and also to compare post-cannulation outcomes.

RESULTS

Among 81,143 patients, 15,880 (19.6%) had AVG and 65,263 (80.4%) had AVF. AVG patients were more likely than AVF patients to achieve TNC at 1 year on unadjusted (77.4% vs 64.0%, p < 0.001) and on multivariate analysis (sHR = 2.56 (2.49-2.63), p < 0.001). For AVFs, one AM surgical procedure was associated with improved 1-year TNC rates, but further revisions were not helpful. Endovascular AM procedures were associated with increased AVF TNC rates. Any procedure, surgical or endovascular, was detrimental to achieving TNC for AVGs.Following initial TNC, those accesses that needed AM procedures were associated with higher rates of access failure (AVF: OR = 1.32 (1.21-1.45); AVG: OR = 1.77 (1.500-2.00); p < 0.001), catheter replacement (AVF: OR = 1.27 (1.20-1.34); AVG: OR = 1.56 (1.42-1.71), p < 0.001), and additional endovascular procedures (AVF: 0.75 ± 1.22 no AM vs 1.33 ± 1.62 any AM; AVG: 1.31 ± 1.77 no AM vs 1.96 ± 2.22 any AM; all p < 0.001).

CONCLUSIONS

AVG achieved TNC after creation more reliably than AVF. A single surgery or endovascular procedures for AVFs is associated with greater rates of TNC. For AVGs, any AM procedure is associated with lower cannulation rates, and reinforces the need for careful operative technique.

Improved outpatient medical visit compliance with sociodemographic discrepancies in vascular telehealth evaluations

OBJECTIVE

The COVID-19 (coronavirus disease 2019) pandemic has led to a rapid expansion in the use of telemedicine across all medical fields but has also exposed telehealth care disparities with differing access to technology across racial and ethnic groups. The objective of our study was to investigate the effects of telehealth on vascular visit compliance and to explore the effects of sociodemographic factors on vascular surgery outpatient telehealth usage during the COVID-19 pandemic.

METHODS

Consecutive patients who had undergone an outpatient vascular surgery evaluation between February 24, 2020 (the launch of our telemedicine program) and December 31, 2020, were reviewed. The baseline demographic and outcomes were obtained from the electronic medical records. Telehealth and in-person evaluations were defined according to the patient's index visit during the study period. Medical visit compliance was established on completion of the telehealth or in-person encounter. We used χ² tests and logistic regression analyses.

RESULTS

A total of 23,553 outpatient visits had been scheduled for 10,587 patients during the study period. Of the outpatient visits, 1559 had been scheduled telehealth encounters compared with 21,994 scheduled in-person encounters. Of the scheduled outpatient encounters, 13,900 medical visits (59.0%) had been completed: 1183 telehealth visits and 12,717 in-person visits. The mean travel distance saved for the telehealth visits was 22.1 ± 27.1 miles, and the mean travel time saved was 46.3 ± 41.47 minutes. We noted no sociodemographic differences between the patients scheduled for telehealth vs in-person visits. We found a trend toward a lower proportion of African-American patients in the telehealth group vs the in-person group (7.8% vs 10.6%; P = .116), without statistical significance. A significantly higher rate of medical visit completion was found for the telehealth group compared with the in-person group (79.5% vs 59.4%; P < .001). Among the patients scheduled for an outpatient medical visit, a scheduled telemedicine evaluation (vs in-person) was associated with 2.3 times the odds of completing the medical visit (odds ratio, 2.31; 95% confidence interval, 2.05-2.61), adjusting for age, sex, race, ethnicity, language, and the distance between the patient's home zip code and the outpatient vascular center's zip code. Selecting for scheduled telemedicine visits, African-American race was associated with a decreased odds of telemedicine usage (odds ratio, 0.73; 95% confidence interval, 0.59-0.90) after adjusting for age, sex, ethnicity, language, and visit type.

CONCLUSIONS

Use of the vascular surgery outpatient telehealth evaluation appeared to improve medical visit completion in our region with apparent sociodemographic disparities. Further studies are needed to confirm whether telemedicine expansion has improved access to care in other geographic areas.

The Unstable Carotid Plaque

Carotid revascularization is performed to prevent cerebrovascular events in patients with symptomatic (>50%) and asymptomatic high degree (>70%) carotid stenosis. As this operation carries significant risks for perioperative stroke, careful selection of patients who will benefit from the procedure is essential. Certain plaque characteristics, including texture, are associated with increased tendency for rupture and can be used to identify high-risk patients. Medical therapy, carotid endarterectomy, and carotid stenting are the mainstays for patient management. With careful selection of patients, all anesthesia techniques (general anesthesia, monitored anesthesia care, and regional anesthesia) can be used safely for these revascularization procedures.

Recurrent Sporadic Bilateral Retinoblastoma in a Child with 13q Deletion Syndrome

13q syndrome is a chromosomal abnormality in which there is a pathognomic deletion of the genetic material on the long arm (q) of chromosome 13. Phenotypes of this syndrome are variable depending on the location of the deleted segment. The main manifestations of the syndrome include mental retardation, craniofacial dysmorphism, and increased susceptibility to tumors. We report a unique case of recurrent sporadic bilateral retinoblastoma (Rb) in a four-year-old boy carrying 13q (q12q14) interstitial deletion, which was treated successfully via enucleation and chemotherapy. Where most patients with familial Rb receive a single mutated Rb1 allele as the ‘first hit’, a small number of patients encounter interstitial deletion of the long arm of chromosome 13, resulting in the loss of the tumor suppressor Rb1 gene and presenting as sporadic cases.