Use of the distal radial artery remnant for autogenous radial-cephalic wrist fistula after radial artery harvest for coronary artery bypass grafting

Harvesting of the radial artery is a common technique used to provide conduit for coronary artery bypass graft surgery. We report the case of a patient with exhausted left upper extremity access options, history of left upper extremity dialysis access-associated steal syndrome, and prior right radial artery harvest for coronary artery bypass graft who received an autogenous distal radial artery remnant to cephalic vein wrist fistula.

Endovascular Treatment of Dialysis Access-Induced Hand Ischemia Using a Flared Stent-Graft

PURPOSE

To report an investigation of a purely endovascular procedure to address access-induced hand ischemia in dialysis patients.

CASE REPORT

Two dialysis patients presented with stage III steal syndrome consisting of severe pain and numbness in their fingers. Preoperative fistulograms distal to the anastomosis showed alternating antegrade and retrograde flow. Under ultrasound guidance, the fistula was accessed and a 4-F micropuncture sheath placed. An angled guidewire was then advanced proximally into the brachial artery. A 6-F short sheath with marker was placed followed by a 4-F straight guide catheter inserted into the proximal brachial artery. A 9-F Flair endovascular stent-graft was advanced over a 0.035-inch stiff angled Glidewire into the fistula just distal to the arterial anastomosis and deployed. Postoperatively, pain and numbness resolved in both patients immediately. Postoperative fistulograms documented antegrade flow. Access flow velocity readings decreased significantly and pulse oximetry readings increased significantly in both patients, who were followed for >6 months with no reported complications.

CONCLUSION

These 2 cases suggest that this endovascular approach to access-induced hand ischemia may be a viable alternative to open/hybrid surgery.

An anatomic risk model to screen post endovascular aneurysm repair patients for aneurysm sac enlargement

BACKGROUND

Follow-up computed tomography angiography (CTA) scans add considerable postimplantation costs to endovascular aneurysm repairs (EVARs) of abdominal aortic aneurysms (AAAs). By building a risk model, we hope to identify patients at low risk for aneurysm sac enlargement to minimize unnecessary CTAs.

METHODS

895 consecutive patients who underwent EVAR for AAA were reviewed, of which 556 met inclusion criteria. A Probit model was created for aneurysm sac enlargement, with preoperative aneurysm morphology, patient demographics, and operative details as variables.

RESULTS

Our final model included 287 patients and had a sensitivity of 100%, a specificity of 68.9%, and an accuracy of 70.4%. Ninety-nine (35%) of patients were assigned to the high-risk group, whereas 188 (65%) of patients were assigned to the low-risk group. Notably, regarding anatomic variables, our model reported that age, pulmonary comorbidities, aortic neck diameter, iliac artery length, and aneurysms were independent predictors of post-EVAR sac enlargement. With the exception of age, all statistically significant variables were qualitatively supported by prior literature. With regards to secondary outcomes, the high-risk group had significantly higher proportions of AAA-related deaths (5.1% versus 1.1%, P = 0.037) and Type 1 endoleaks (9.1% versus 3.2%, P = 0.033).

CONCLUSIONS

Our model is a decent predictor of patients at low risk for post AAA EVAR aneurysm sac enlargement and associated complications. With additional validation and refinement, it could be applied to practices to cut down on the overall need for postimplantation CTA.

Vascular surgeon-hospitalist comanagement improves in-hospital mortality at the expense of increased in-hospital cost

OBJECTIVE

We have shown that vascular surgeon- hospitalist co management resulted in improved in-hospital mortality rates. We now aim to assess the impact of the hospitalist co management service (HCS) on healthcare cost.

METHODS

A total of 1558 patients were divided into three cohorts and compared: 516 in 2012, 525 in 2013, and 517 in 2014. The HCS began in January 2013. Data were standardized for six vascular surgeons that were present 2012-2014. New attendings were excluded. Ten hospitalists participated. Case mix index (CMI), contribution margin, total hospital charges (THCs), length of stay (LOS), actual direct costs (ADCs), and actual variable indirect costs (AVICs) were compared. Analysis of variance with post-hoc tests, t-tests, and linear regressions were performed.

RESULTS

THC rose by a mean difference of $14,578.31 between 2012 and 2014 (P < .001) with a significant difference found between all groups during the study period (P = .0004). ADC increased more than AVIC; however, both significantly increased over time (P = .0002 and P = .014, respectively). A mean $3326.63 increase in ADC was observed from 2012 to 2014 (P < .0001). AVIC only increased by an average $392.86 during the study period (P = .01). This increased cost was observed in the context of a higher CMI and longer LOS. CMI increased from 2.25 in 2012 to 2.53 in 2014 (P = .006). LOS increased by a mean 1.02 days between 2012 and 2014 (P = .016), and significantly during the study period overall (P = .018). After adjusting for CMI, LOS increases by only 0.61 days between 2012 and 2014 (P = .07). In a final regression model, THC is independently predicted by comanagement, CMI, and LOS. After adjusting for CMI and LOS, the increase in THC because of comanagement (2012 vs 2014) accounts for only $4073.08 of the total increase (P < .001). During this time, 30-day readmission rates decreased by ∼7% (P = .005), while related 30-day readmission rates decreased by ∼2% (P = .32). Physician contribution margin remained unchanged over the 3-year period (P = .76). The most prevalent diagnosis-related group was consistent across all years. Variation in the principal diagnosis code was observed with the prevalence of circulatory disorders because of type II diabetes replacing atherosclerosis with gangrene as the most prevalent diagnosis in 2013 and 2014 compared with 2012.

CONCLUSIONS

In-hospital cost is significantly higher since the start of the HCS. This surge may relate to increased CMI, LOS, and improved coding. This increase in cost may be justified as we have observed sustained reduction in in-hospital mortality and slightly improved readmission rates.

Thermodynamic contributions to the stability of the insulin hexamer

The insulin hexamer is resistant to degradation and fibrillation, which makes it an important quaternary structure for its in vivo storage in Zn(2+)- and Ca(2+)-rich vesicles in the pancreas and for pharmaceutical formulations. In addition to the two Zn(2+) ions that are required for its formation, three other species, Zn-coordinating anions (e.g., Cl(-)), Ca(2+), and phenols (e.g., resorcinol), bind to the hexamer and affect the subunit conformation and stability. The contributions of these four species to the thermodynamics of insulin unfolding have been quantified by differential scanning calorimetry and thermal unfolding measurements to determine the extent and nature of their stabilization of the insulin hexamer. Both Zn(2+) and resorcinol make a significant enthalpic contribution, while Ca(2+) primarily affects the protein heat capacity (solvation) by its interactions in the central cation-binding cavity, which is modulated by the surrounding subunit conformations. Coordinating anions have a negligible effect on the stability of the hexamer, even though subunits shift to an alternate conformation when these anions bind to the Zn(2+) ions. Finally, Zn(2+) in excess of the two that are required to form the hexamer further stabilizes the protein by additional enthalpic contributions.