Nationwide comparison of the medical complexity of patients by surgical specialty.

OBJECTIVE: Intuitively, the chronic disease burden of surgical patients varies considerably by surgical specialty, although sparse evidence in the literature supports this notion. We sought to characterize the medical complexity of surgical patients by surgical specialty and to quantify the association between medical complexity and outcomes. METHODS: The National Inpatient Sample, an all-payer inpatient database representative of 97% of all U.S. hospitalizations, was used to identify adults undergoing surgery between 2005 and 2014. The most commonly performed operations that constituted 80% of each surgical specialty's practice were abstracted. The previously validated Elixhauser Comorbidity Index (ECI) was calculated per year by surgical specialty as a measure of medical complexity. Outcomes and resource utilization were assessed by comparing mortality rate, length of stay, and cost. RESULTS: An estimated 53,232,144 patients underwent operations in one of nine surgical specialty categories. Surgical specialties were ranked by ECI, with cardiac surgery (3.56), vascular surgery (3.49), and thoracic surgery (2.86) having the highest mean ECI (all P values <.0001 compared with vascular surgery). Whereas the high ECI scores in cardiac surgery were driven by arrhythmias and hypertension, vascular patients had a more uniform distribution of comorbidities. The average ECI for all surgical patients increased during the study period from 2.03 in 2005 to 2.65 in 2014 (P < .001), with a similar trend for all specialties considered. Unlike the two specialties with the lowest burden of comorbidities (orthopedic surgery and endocrine surgery), cardiac surgery and vascular surgery exhibited significantly higher inpatient mortality, LOS, and costs. CONCLUSIONS: Although all surgical patients have exhibited an increase in comorbidities during the past decade, candidates for cardiac and vascular operations appear to carry the largest burden of chronic conditions. Despite caring for patients with the highest burden of comorbidities for emergent operations, vascular surgery did not have the highest mortality, inpatient costs, or length of stay compared with some of the other specialties. The intensity of care and assumed risk in treating medically complex vascular patients should be taken into consideration in deciding health policy, reimbursement, and hospital resource allocation.

A novel technique for transaxillary resection of fully formed cervical ribs with long-term clinical outcomes.

OBJECTIVE: Although the supraclavicular approach has been widely adopted for cervical rib resection, a transaxillary approach has been favored by many. We have reviewed more than two decades of experience with decompression of the thoracic outlet to treat thoracic outlet syndrome (TOS) in patients with complete cervical ribs using a novel transaxillary approach. METHODS: A prospectively maintained database of patients undergoing surgery for TOS was searched for patients with complete (class 3 and 4) cervical ribs from 1997 to 2019. All these patients had undergone transaxillary resection using a technique in which the cervical and first ribs were separated and then individually resected. The data abstracted included patient demographics, symptoms, surgical details, and complications. The outcomes were contemporaneously assessed clinically and using standardized functional tools: somatic pain scale (SPS) and Quick Disabilities of the Arm, Hand, and Shoulder questionnaire (QuickDASH). The cervical rib data were organized and reported in accordance with the Society for Vascular Surgery reporting standards. RESULTS: During the study period, 1506 patients had undergone surgery for TOS at our institution. Of these 1506 patients, 38 had undergone complete transaxillary resection of 40 fully formed cervical ribs (10 class 3 and 30 class 4). Of these 38 patients, 74% were women. The presentations had been neurogenic (65%), arterial (31%), and venous (5%). The average initial SPS and QuickDASH score was 6.4 and 50, respectively. The duration of surgery averaged 141 minutes, blood loss was 65 mL, and length of stay was 2.1 days. None of the patients had experienced brachial plexus, phrenic, or long thoracic nerve injury. The average follow-up period was 65 months. The final mean postoperative SPS and QuickDASH scores were lower than the scores at presentation (SPS score, 6.4 vs 1.2; P < .001; QuickDASH score, 50 vs 17; P < .001). CONCLUSIONS: To the best of our knowledge, the present study is the largest reported experience of resection of fully formed cervical ribs using a transaxillary approach that allowed for individual dissection and removal of cervical and first rib segments. This technique has proved to be successful, with low morbidity and reliable improvement in patient symptom and disability scores. Based on these reported outcomes, this novel approach to transaxillary resection of fully formed cervical ribs should be considered a safe and effective operation.

New predictors of complications in carotid body tumor resection.

OBJECTIVE: This study examined the relationship between two new variables, tumor distance to base of skull (DTBOS) and tumor volume, with complications of carotid body tumor (CBT) resection, including bleeding and cranial nerve injury. METHODS: Patients who underwent CBT resection between 2004 and 2014 were studied using a standardized, multi-institutional database. Demographic, perioperative, and outcomes data were collected. CBT measurements were determined from computed tomography, magnetic resonance imaging, and ultrasound examination. RESULTS: There were 356 CBTs resected in 332 patients (mean age, 51 years; 72% female); 32% were classified as Shamblin I, 43% as Shamblin II, and 23% as Shamblin III. The mean DTBOS was 3.3 cm (standard deviation [SD], 2.1; range, 0-10), and the mean tumor volume was 209.7 cm3 (SD, 266.7; range, 1.1-1642.0 cm3). The mean estimated blood loss (EBL) was 257 mL (SD, 426; range, 0-3500 mL). Twenty-four percent of patients had cranial nerve injuries. The most common cranial nerves injured were the hypoglossal (10%), vagus (11%), and superior laryngeal (5%) nerves. Both Shamblin grade and DTBOS were statistically significantly correlated with EBL of surgery and cranial nerve injuries, whereas tumor volume was statistically significantly correlated with EBL. The logistic model for predicting blood loss and cranial nerve injury with all three variables-Shamblin, DTBOS, and volume (R2 = 0.171, 0.221, respectively)-was superior to a model with Shamblin alone (R2 = 0.043, 0.091, respectively). After adjusting for Shamblin grade and volume, every 1-cm decrease in DTBOS was associated with 1.8 times increase in risk of >250 mL of blood loss (95% confidence interval, 1.25-2.55) and 1.5 times increased risk of cranial nerve injury (95% confidence interval, 1.19-1.92). CONCLUSIONS: This large study of CBTs demonstrates the value of preoperatively determining tumor dimensions and how far the tumor is located from the base of the skull. DTBOS and tumor volume, when used in combination with the Shamblin grade, better predict bleeding and cranial nerve injury risk. Furthermore, surgical resection before expansion toward the base of the skull reduces complications as every 1-cm decrease in the distance to the skull base results in 1.8 times increase in >250 mL of blood loss and 1.5 times increased risk of cranial nerve injury.

Acute Aortic Dissection and Intramural Hematoma: A Systematic Review.

IMPORTANCE: Acute aortic syndrome (AAS), a potentially fatal pathologic process within the aortic wall, should be suspected in patients presenting with severe thoracic pain and hypertension. AAS, including aortic dissection (approximately 90% of cases) and intramural hematoma, may be complicated by poor perfusion, aneurysm, or uncontrollable pain and hypertension. AAS is uncommon (approximately 3.5-6.0 per 100,000 patient-years) but rapid diagnosis is imperative as an emergency surgical procedure is frequently necessary. OBJECTIVE: To systematically review the current evidence on diagnosis and treatment of AAS. EVIDENCE REVIEW: Searches of MEDLINE, EMBASE, and the Cochrane Register of Controlled Trials for articles on diagnosis and treatment of AAS from June 1994 to January 29, 2016, were performed. Only clinical trials and prospective observational studies of 10 or more patients were included. Eighty-two studies (2 randomized clinical trials and 80 observational) describing 57,311 patients were reviewed. FINDINGS: Chest or back pain was the most commonly reported presenting symptom of AAS (61.6%-84.8%). Patients were typically aged 60 to 70 years, male (50%-81%), and had hypertension (45%-100%). Sensitivities of computerized tomography and magnetic resonance imaging for diagnosis of AAS were 100% and 95% to 100%, respectively. Transesophageal echocardiography was 86% to 100% sensitive, whereas D-dimer was 51.7% to 100% sensitive and 32.8% to 89.2% specific among 6 studies (n = 876). An immediate open surgical procedure is needed for dissection of the ascending aorta, given the high mortality (26%-58%) and proximity to the aortic valve and great vessels (with potential for dissection complications such as tamponade). An RCT comparing endovascular surgical procedure to medical management for uncomplicated AAS in the descending aorta (n = 61) revealed no dissection-related deaths in either group. Endovascular surgical procedure was better than medical treatment (97% vs 43%, P < .001) for the primary end point of "favorable aortic remodeling" (false lumen thrombosis and no aortic dilation or rupture). The remaining evidence on therapies was observational, introducing significant selection bias. CONCLUSIONS AND RELEVANCE: Because of the high mortality rate, AAS should be considered and diagnosed promptly in patients presenting with acute chest or back pain and high blood pressure. Computerized tomography, magnetic resonance imaging, and transesophageal echocardiography are reliable tools for diagnosing AAS. Available data suggest that open surgical repair is optimal for treating type A (ascending aorta) AAS, whereas thoracic endovascular aortic repair may be optimal for treating type B (descending aorta) AAS. However, evidence is limited by the paucity of randomized trials.

Endovascular-first approach is not associated with worse amputation-free survival in appropriately selected patients with critical limb ischemia.

OBJECTIVE: Endovascular interventions for critical limb ischemia are associated with inferior limb salvage (LS) rates in most randomized trials and large series. This study examined the long-term outcomes of selective use of endovascular-first (endo-first) and open-first strategies in 302 patients from March 2007 to December 2010. METHODS: Endo-first was selected if (1) the patient had short (5-cm to 7-cm occlusions or stenoses in crural vessels); (2) the disease in the superficial femoral artery was limited to TransAtlantic Inter-Society Consensus II A, B, or C; and (3) no impending limb loss. Endo-first was performed in 187 (62%), open-first in 105 (35%), and 10 (3%) had hybrid procedures. RESULTS: The endo-first group was older, with more diabetes and tissue loss. Bypass was used more to infrapopliteal targets (70% vs 50%, P = .031). The 5-year mortality was similar (open, 48%; endo, 42%; P = .107). Secondary procedures (endo or open) were more common after open-first (open, 71 of 105 [68%] vs endo, 102 of 187 [55%]; P = .029). Compared with open-first, the 5-year LS rate for endo-first was 85% vs 83% (P = .586), and amputation-free survival (AFS) was 45% vs 50% (P = .785). Predictors of death were age >75 years (hazard ratio [HR], 3.3; 95% confidence interval [CI], 1.7-6.6; P = .0007), end-stage renal disease (ESRD) (HR, 3.4; 95% CI, 2.1-5.6; P < .0001), and prior stroke (HR, 1.6; 95% CI, 1.03-2.3; P = .036). Predictors of limb loss were ESRD (HR, 2.5; 95% CI, 1.2-5.4; P = .015) and below-the-knee intervention (P = .041). Predictors of worse AFS were older age (HR, 2.03; 95% CI, 1.13-3.7; P = .018), ESRD (HR, 3.2; 95% CI, 2.1-5.11; P < .0001), prior stroke (P = .0054), and gangrene (P = .024). CONCLUSIONS: At 5 years, endo-first and open-first revascularization strategies had equivalent LS rates and AFS in patients with critical limb ischemia when properly selected. A patient-centered approach with close surveillance improves long-term outcomes for both open and endo approaches.

Immune-mediated loss of transgene expression from virally transduced brain cells is irreversible, mediated by IFNγ, perforin, and TNFα, and due to the elimination of transduced cells.

The adaptive immune response to viral vectors reduces vector-mediated transgene expression from the brain. It is unknown, however, whether this loss is caused by functional downregulation of transgene expression or death of transduced cells. Herein, we demonstrate that during the elimination of transgene expression, the brain becomes infiltrated with CD4(+) and CD8(+) T cells and that these T cells are necessary for transgene elimination. Further, the loss of transgene-expressing brain cells fails to occur in the absence of IFNγ, perforin, and TNFα receptor. Two methods to induce severe immune suppression in immunized animals also fail to restitute transgene expression, demonstrating the irreversibility of this process. The need for cytotoxic molecules and the irreversibility of the reduction in transgene expression suggested to us that elimination of transduced cells is responsible for the loss of transgene expression. A new experimental paradigm that discriminates between downregulation of transgene expression and the elimination of transduced cells demonstrates that transduced cells are lost from the brain upon the induction of a specific antiviral immune response. We conclude that the anti-adenoviral immune response reduces transgene expression in the brain through loss of transduced cells.

Development of the Drosophila entero-endocrine lineage and its specification by the Notch signaling pathway.

In this paper we have investigated the developmental-genetic steps that shape the entero-endocrine system of Drosophila melanogaster from the embryo to the adult. The process starts in the endoderm of the early embryo where precursors of endocrine cells and enterocytes of the larval midgut, as well as progenitors of the adult midgut, are specified by a Notch signaling-dependent mechanism. In a second step that occurs during the late larval period, enterocytes and endocrine cells of a transient pupal midgut are selected from within the clusters of adult midgut progenitors. As in the embryo, activation of the Notch pathway triggers enterocyte differentiation and inhibits cells from further proliferation or choosing the endocrine fate. The third step of entero-endocrine cell development takes place at a mid-pupal stage. Before this time point, the epithelial layer destined to become the adult midgut is devoid of endocrine cells. However, precursors of the intestinal midgut stem cells (pISCs) are already present. After an initial phase of symmetric divisions which causes an increase in their own population size, pISCs start to spin off cells that become postmitotic and express the endocrine fate marker, Prospero. Activation of Notch in pISCs forces these cells into an enterocyte fate. Loss of Notch function causes an increase in the proliferatory activity of pISCs, as well as a higher ratio of Prospero-positive cells.