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Background Adjuncts for early detection and treatment of spinal cord ischemia (SCI) in thoracic aortic surgery are supported by robust clinical experience in open repair. The utility of cerebrospinal fluid (CSF) drainage and neurophysiologic monitoring (NPM) in thoracic endovascular aortic repair (TEVAR) is less clear. The purpose of this investigation is to determine the influence of a selective institutional spinal cord protection protocol using prophylactic NPM and CSF on outcomes for standard TEVAR. Methods Patients undergoing standard TEVAR entered into a prospectively maintained database from a single institution from 2007 to 2016 were retrospectively reviewed. Preoperative characteristics, aneurysm extent, and etiology were reviewed. Utilization of CSF drains including volume of fluid removed, duration of drainage, and catheter-related complications were collected. NPM data were reviewed to determine the influence on intraoperative management. Exact logistic regression was used to identify independent predictors of SCI. Results Of 223 patients undergoing TEVAR, 130 met inclusion criteria for the study. CSF drains were used in 71 patients (54.6%), and 56 of 130 (43%) had NPM. SCI occurred in 7 patients (5.4%), of whom 5 had partial or complete recovery. Median time to symptoms of SCI was delayed in all cases (median 52 hr, range 8–312), and none of the 4 of 7 patients with adjunct NPM demonstrated intraoperative changes. Intraoperative changes in NPM occurred in 26 (46%), and represented unilateral leg ischemia in all but 2 cases. In both patients, changes consistent with SCI were associated with intraoperative hypotension and resolved with blood pressure augmentation. Neither patient developed postoperative SCI. Median length of stay (22 vs. 9 days, P = 0.012), operative room time (262 vs. 209, P = 0.040), and perioperative mortality (28.6% vs. 4.1%, P = 0.046) were significantly higher for patients with SCI versus those without. Length of aortic coverage was found to be the sole independent predictor of SCI (odds ratio 8.2, P = 0.026). Complications related to CSF drainage occurred in 4 patients (5.6%) with major complications occurring in 2 patients (2.8%), including 1 with an intrathecal hematoma and permanent bilateral paraparesis. Conclusions Selective use of prophylactic CSF drainage in TEVAR was associated with moderate risk and questionable benefit. The use of neurophysiological monitoring allowed for early detection and treatment of spinal ischemia, but its utility is limited by logistical factors and to the minority of patients with intraoperative spinal ischemic events.

SummaryIt was the objective of this study to obtain best estimates of the prevalence of anti-PF4/heparin antibodies in patients not suspected to have clinical heparin-induced thrombocytopenia (HIT) prior to undergoing cardiac surgery and to determine whether preoperative antibody status and antibody class is predictive of postoperative thromboembolic outcomes, non-thromboembolic outcomes, length of stay, and mortality. PubMed and EMBASE online databases were searched up to July 2011, and we included studies involving adults undergoing cardiac surgery examining the relationship between preoperative anti-PF4/heparin antibodies (ELISA) and postoperative clinical outcomes. Five studies involving a combined total of 2,332 patients met our inclusion criteria. Preoperative anti-PF4/heparin antibodies were detected in 5–22% of patients. No study demonstrated an association between preoperative anti-PF4/heparin antibodies and postoperative thromboembolic outcomes or mortality. Three studies demonstrated a statistically significant association between preoperative anti-PF4/heparin antibodies and length of stay while two showed an association with non-thromboembolic complications. In the one study that examined outcomes by anti-PF4/heparin antibody class, IgM antibodies predicted non-thromboembolic complications and length-of-stay. None of the studies reported prior heparin exposure, and most studies did not examine the relationship of the absolute value of antibody titres (ELISA OD) and risk, nor the incidence of true/clinical HIT in preoperative positive or negative patients. In conclusion, pre-formed anti-PF4/heparin antibodies are common in patients undergoing cardiac surgery, but the available literature does not support that they predict postoperative thromboembolic complications or death. There does appear to be an association between anti-PF4/heparin antibodies and non-thromboembolic adverse events, but a causal relationship is unlikely.

Objective: To compare the potency, reversibility, and perioperative bleeding risk of Hepalean with those of PPC heparin. Conclusions: PPC heparin use was associated with greater heparin and protamine dose requirements than Hepalean. These findings indicate that heparin preparations are not interchangeable and suggest that a direct comparison of the potency with the brand in use is needed if a change is made to ensure that the agents exert similar anticoagulant effects in vivo. Methods: Because in vitro testing failed to detect differences in the potency or protamine reversibility of the 2 heparin preparations, we conducted a parallel group, single-center, double-blind, randomized, controlled trial to compare the anticoagulant effects of Hepalean to those of PPC heparin in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass. Results: From June 1, 2011, to June 30, 2011, we randomly assigned 11 patients to receive PPC heparin and 10 to receive Hepalean. Despite similar initial doses of heparin, the median initial activated clotting time was numerically lower in the PPC heparin group than in the Hepalean group (median, 516.0 seconds; interquartile range, 481.0-633.0; vs median, 584.0 seconds, interquartile range, 520.0-629.0; P = .418). Those given PPC heparin required a greater total heparin dose (median, 46,000.0 U; interquartile range, 39,500.0-60,000.0 vs median, 34,500.0 U; interquartile range, 32,250.0-37,000.0; P = .011) and a greater dose of heparin per kilogram than those given Hepalean (median, 572.9 U/kg; interquartile range, 443.0-659.7 vs median, 401.1 U/kg; interquartile range, 400.0-419.4; P = .003). The key secondary results included an increased median total protamine dose (median, 600.0 mg; interquartile range, 550.0-700.0; vs median, 500.0 mg; interquartile range, 425.0-542.5; P = .026) and a trend toward increased chest tube output within 24 hours (median, 830.0 mL; interquartile range, 425.0-1135.0; vs median, 702.5 mL; interquartile range, 550.0-742.5; P = .324). Refereed/Peer-reviewed