Increased Surgical Site Infection Rates following Clindamycin Use in Head and Neck Free Tissue Transfer.

OBJECTIVE: The development of surgical site infections (SSIs) can put the viability of free tissue transfer reconstructions at risk, often resulting in considerable postoperative morbidity and prolonged hospitalization. Current antibiotic prophylactic guidelines suggest a first- or second-generation cephalosporin with metronidazole for clean-contaminated cases and recommend clindamycin as an alternative choice in penicillin-allergic patients. This study was designed to examine the rates of postoperative infection associated with prophylactic antibiotic regimens, including patients receiving clindamycin as an alternative due to penicillin allergy. STUDY DESIGN: Case series with chart review. SETTING: Tertiary academic medical center. SUBJECTS: Patients undergoing major ablative head and neck resection involving the pharynx and oral cavity reconstructed via free tissue transfer. METHODS: The sample included patients (n = 266) who underwent free tissue transfer involving the oral cavity and pharynx from 2009 to 2014. Data included demographic data, medical comorbidities, anatomic tumor subsite and surgical procedure, and prophylactic antibiotic regimen. SSI data were examined up to 30 days after the initial surgical procedure. Multivariate logistic regression analysis was performed to determine the overall risk for SSI. Culture data were also reviewed. RESULTS: The data indicated that clindamycin was associated with an approximate 4-fold increased risk for SSI (odds ratio, 3.784; 95% confidence interval: 1.367-10.470 [P = .010]) after controlling for possible confounding factors. CONCLUSION: For patients with a true penicillin allergy, we recommend broader gram-negative coverage with alternative antibiotics, such as cefuroxime, when undergoing free tissue transfer in the head and neck.

Frontorbital Fibrous Dysplasia Resection and Reconstruction With Custom Polyetherlatone Alloplast.

Fibrous dysplasia (FD) is a benign, pathological development of bone. Craniofacial bones are the most commonly involved and can potentially cause visual disturbance, proptosis, orbital dystopia, and facial deformity. This case involves a 13-year-old girl with significant proptosis (20 mm left, 17.5 mm right) and downward displacement of the left globe (1.5 mm) due to fibrous dysplasia. Reconstruction was performed with computed tomography-derived and 3D printed custom polyetheretherketone (PEEK) implantation. PEEK is a nonabsorbable, nonporous thermoplastic polymer notable for its ability to be modified intraoperatively and ideal imaging properties postoperatively. Never, to our knowledge, has PEEK been used for primary reconstruction of the frontal orbital region in fibrous dysplasia in a child. The lesion was successfully repaired with excellent aesthetic and no apparent damage to neurovascular or ocular structures.

Advanced heart failure in patients infected with human immunodeficiency virus: is there equal access to care?

BACKGROUND: Human immunodeficiency virus (HIV) infection has evolved from a highly stigmatized disease with certain progression to acquired immunodeficiency syndrome (AIDS) to a chronic disease affecting over 1 million Americans. With the success of current anti-retroviral therapies, cardiovascular disease, including advanced heart failure (HF), will be a major cause of morbidity and mortality in this population. METHODS: A survey concerning heart transplantation (HT) and left ventricular assist device (LVAD) implantation attitudes and outcomes in HIV-infected patients was distributed to 103 American and 9 Canadian HT centers via fax, e-mail or telephone. RESULTS: Eighty-nine centers (79%) responded. Eighteen HTs were performed in HIV(+) patients with 1-, 2- and 5-year survival of 100%, 100% and 63%, respectively. Eighty-two centers (92%) have never performed HT in HIV(+) patients and 51 centers (57%) marked HIV(+) status as a contraindication. Rationales for contraindication included: (1) high-risk patients should be avoided given the scarcity of organ supply (59%); (2) immunosuppression required for HT may induce progression to AIDS (51%); and (3) drug interactions may worsen patients' clinical outcomes (49%). Thirty-five left ventricular assist device (LVAD) implantations in HIV(+) patients were reported. Sixty-eight centers (76%) have never implanted an LVAD in an HIV(+) patient and 21 centers (20%) marked HIV(+) status as a contraindication, of which 61% indicated concern for device-related infection. CONCLUSIONS: Most centers either explicitly consider HIV(+) status as a contraindication for or have never treated HIV(+) patients with advanced HF therapy. Our findings suggest unequal access to care and underscore the need to educate cardiovascular health-care providers on progress made with HIV therapies.

Pre-operative mortality risk assessment in patients with continuous-flow left ventricular assist devices: application of the HeartMate II risk score.

BACKGROUND: Survival with left ventricular assist device (LVAD) therapy is dependent on appropriate patient selection. The HeartMate II risk score (HMRS) was recently derived and validated to predict 90-day mortality in clinical trial patients with continuous-flow LVADs. The aim of this study was to test HMRS validity in predicting survival at our institution. METHODS: We performed a retrospective analysis of patients implanted with HeartMate II (HMII; Thoratec, Pleasanton, CA) LVADs from March 31, 2004 to September 20, 2012 at the Columbia University Medical Center (CUMC). Patients were stratified according to HMRS profiles (HMRS Low < 1.58, 1.58 ≤ HMRS Medium ≤ 2.48, HMRS High > 2.48) calculated using age, albumin, creatinine, international normalized ratio (INR) and center volume. Outcome was defined as survival at 90 days after device implantation. RESULTS: HeartMate II LVADs were implanted in 205 patients. Pre-operative data from 201 patients were categorized into HMRS Low (n = 101; 1.04 [0.64 to 1.31]), HMRS Medium (n = 73; 1.98 [1.78 to 2.25]) and HMRS High (n = 27, 3.07 [2.70 to 3.43]) (p < 0.0001). Kaplan-Meier survival estimates at 90 days (HMRS Low 91.0 ± 2.9%, HMRS Medium 91.7 ± 3.2%, HMRS High 88.7 ± 6.1%) and at 1 year (HMRS Low 85.5 ± 3.8%, HMRS Medium 79.3 ± 5.5%, HMRS High 82.4 ± 8.4%) after LVAD implantation were not statistically different (p = 0.43). Prediction of 90-day mortality by receiver operating characteristic was poor (AUC = 0.56). CONCLUSION: HMRS stratification poorly discriminates 90-day mortality after HMII LVAD implantation at our institution. Its generalizability as a universal prognostic score may be limited.

Prevalence, significance, and management of aortic insufficiency in continuous flow left ventricular assist device recipients.

BACKGROUND: Aortic insufficiency (AI) is increasingly recognized as a complication of continuous flow left ventricular assist device support; however, its long-term prevalence, clinical significance, and efficacy of potential interventions are not well known. METHODS AND RESULTS: We studied the prevalence and management of AI in 232 patients with continuous flow left ventricular assist device at our institution. Patients with aortic valve (AV) surgery before left ventricular assist device implantation were excluded from analysis. To examine the prevalence of de novo AI, patients without preoperative AI were divided into a retrospective and a prospective cohort based on whether a dedicated speed optimization study had been performed at the time of discharge. Forty-three patients underwent AV repair at the time of implant, and 3 subsequently developed greater than mild AI. In patients without surgical AV manipulation and no AI at the time of implant, Kaplan-Meier analysis revealed that freedom from greater than mild de novo AI at 1 year was 77.6±4.2%, and that at least moderate AI is expected to develop in 37.6±13.3% after 3 years. Nonopening of the AV was strongly associated with de novo AI development in patients without prospective discharge speed optimization. Seven of 21 patients with at least moderate AI developed symptomatic heart failure requiring surgical intervention. CONCLUSIONS: AI is common in patients with continuous flow left ventricular assist devices and may lead to clinical decompensation requiring surgical correction. The prevalence of AI is substantially less in patients whose AV opens, and optimized loading conditions may reduce AI prevalence in those patients in whom AV opening cannot be achieved.

Device thrombosis in HeartMate II continuous-flow left ventricular assist devices: a multifactorial phenomenon.

BACKGROUND: Continuous-flow left ventricular assist devices (CF-LVADs) are increasingly used to support patients with advanced heart failure (HF). Device thrombosis is a serious complication of CF-LVADs, but its precise prevalence and etiology remains uncertain. METHODS: Root-cause analysis was performed in all cases with device thrombosis confirmed upon explant among patients implanted with a HeartMate II (HM II) from January 1, 2009 to November 15, 2012. Cannula position and bend relief integrity were assessed and charts were reviewed with particular attention to anti-coagulation and infection profiles. RESULTS: Nineteen of 177 patients (11%) were found to have device thrombosis of various etiologies after a mean of 351 ± 311 days, representing 0.12 event/patient-year. Of the 5 mechanically induced thromboses, proximate etiology was severely abnormal inflow cannula position in 3 patients and bend relief disconnect with deformed outflow graft in 2 patients. One patient had a hypercoagulable disorder with prior arterial embolism. In the remaining 13 patients (age 61 ± 14 years, 77% male, 69% Caucasian), "non-mechanical" device thrombosis occurred after 357 ± 383 days; INR at the time of diagnosis was 1.81 (1.62 to 2.07); and mean device speed was 8,855 ± 359 rpm. Five of 13 patients (38%) had an infection during the month leading up to device thrombosis. Of note, lactate dehydrogenase (LDH) was already elevated at the time of discharge in patients who would later develop non-mechanical device thrombosis (423 [354 to 766] vs 352 [272 to 373] U/liter, p < 0.01). CONCLUSIONS: Device thrombosis is a multifactorial phenomenon, and differentiation of mechanical and non-mechanical causes is an essential step for individual diagnosis and treatment plans. Larger studies excluding patients with obvious mechanical etiology are needed to investigate biologic and/or management-related risk factors for device thrombosis. Our findings suggest that LDH may be an early risk marker. Due to the difficulty in treating late-stage device thrombosis, we suggest early use of simple tests to rule out both causes of thrombosis, such as X-rays and closer LDH monitoring (bi-weekly).

Value of serial echo-guided ramp studies in a patient with suspicion of device thrombosis after left ventricular assist device implantation.

Thrombus formation inside of the pump is a major cause for device malfunction following the left ventricular assist device (LVAD) implantation. We recently established a novel ramp test protocol facilitating continuous bedside echo monitoring to optimize LVAD function and diagnosing device malfunctions. We describe a case of 29-year-old woman undergoing HeartMate II LVAD implantation, in whom serial ramp studies were used to diagnose intra-device thrombus after device implantation. The 1st ramp study at postoperative day (POD) 26 revealed adequate reduction in ventricular size according to the increase in LVAD speed (left ventricular end-diastolic diameter [LVEDD] at minimum and maximum speeds, 68 and 37 mm, respectively). The patient was discharged home and received routine anticoagulation maintenance therapy. However, a 2nd ramp test was performed on POD 56 due to increased lactase dehydrogenase and brain natriuretic peptide levels and showed marked increase in left ventricle (LV) chamber size without adequate response to the LVAD speed changes (LVEDD at minimum and maximum speeds, 88 and 76 mm, respectively). Given the suspicion for partial pump thrombosis, the patient was immediately hospitalized and received intravenous heparin infusion. After the optimization of the intensive anticoagulation therapy, the patient underwent a 3rd ramp study, which showed a remarkable improvement of the adequate response to LVAD speed changes. The patients eventually underwent cardiac transplant successfully, and the partial clot was found inside of the pump. This case demonstrates the usefulness of serial ramp studies in patients who are suspected to have device thrombosis.

Experimental and computational evidence of metal-O2 activation and rate-limiting proton-coupled electron transfer in a copper amine oxidase.

The mechanism of O(2) reduction by copper amine oxidase from Arthrobacter globiformus (AGAO) is analyzed in relation to the cobalt-substituted protein. The enzyme utilizes a tyrosine-derived topaquinone cofactor to oxidize primary amines and reduce O(2) to H(2)O(2). Steady-state kinetics indicate that amine-reduced CuAGAO is reoxidized by O(2) >10(3) times faster than the CoAGAO analogue. Complementary spectroscopic studies reveal that the difference in the second order rate constant, k(cat)/K(M)(O(2)), arises from the more negative redox potential of Co(III/II) in relation to Cu(II/I). Indistinguishable competitive oxygen-18 kinetic isotope effects are observed for the two enzymes and modeled computationally using a calibrated density functional theory method. The results are consistent with a mechanism where an end-on (η(1))-metal bound superoxide is reduced to an η(1)-hydroperoxide in the rate-limiting step.

Adrenergic activation, fuel substrate availability, and insulin resistance in patients with congestive heart failure.

OBJECTIVES: This study sought to investigate plasma levels of glucose and free fatty acids (FFA) and their relationship with adrenergic activation and insulin resistance (IR) in patients with advanced congestive heart failure (CHF). BACKGROUND: Adrenergic activation and IR are hallmarks of advanced heart failure. The resulting changes in fuel substrate availability and their implications for exercise capacity have not been elucidated. METHODS: Subjects with CHF underwent maximal exercise testing. Plasma glucose, FFA, insulin, and norepinephrine (NE) levels were measured at rest and at peak exercise. Beta-receptor sensitivity to NE was assessed using the Chronotropic Responsiveness Index (CRI). Homeostasis Model Assessment Index >2.5 defined IR. Left ventricular ejection fraction was estimated by 2-dimensional echocardiography. RESULTS: Ninety-six subjects were enrolled. CHF subjects without IR (CHF/No-IR), but not those with IR (CHF/IR), significantly increased glucose and insulin in response to exercise. Only CHF/No-IR subjects increased FFA in response to exercise (0.14 ± 0.27 mmol/l; p = 0.027). NE increased significantly less with exercise, and CRI was lower in CHF/IR subjects compared with CHF/No-IR subjects (1.3 ± 1.4 vs. 2.5 ± 2.1; 6.4 ± 2.6 vs. 8.5 ± 3.4; p = 0.069). CRI correlated with the exercise-induced increase in FFA (r = 0.41; p < 0.005). These results stayed the same after excluding diabetic patients from the CHF/IR group. CONCLUSIONS: Circulating FFA levels increased during exercise in CHF subjects without IR, but not in those with IR or DM. Increased FFA availability during exercise may represent a catecholamine-dependent compensatory fuel shift in CHF.