Evaluation of left ventricular reverse remodeling in patients with severe aortic regurgitation undergoing aortic valve replacement: Comparison between diameters and volumes.

BACKGROUND: In patients with severe aortic regurgitation (AR), the left ventricular ejection fraction (LVEF) and left ventricle (LV) size are crucial for determining clinical prognosis and timing of valve intervention. In clinical practice, LV internal diameters obtained at end-diastole are used to assess the degree of LV dilatation. Whether quantification of LV volumes would provide more robust information as compared to LV linear dimensions is unknown. METHODS: We retrospectively analyzed preoperative and postoperative transthoracic echocardiograms of patients who underwent aortic valve replacement (AVR) for severe AR. Indexed linear LV end-diastolic and end-systolic diameters along with indexed LV end-diastolic and end-systolic volumes were obtained as per current guidelines. Post-AVR LV reverse remodeling, defined as ≥10% reduction in measures of LV volumes (Teichholz and Simpson's methods), was determined. Positive and negative agreement was calculated between the volume- and diameter-based LV reverse remodeling. RESULTS: Sixty-two consecutive patients were included. Nine patients (17%) without LV reverse remodeling based on Teichholz were reclassified as having LV reverse remodeling based on Simpson (positive agreement 0.846 [95% CI 0.772, 0.921], negative agreement 0.200 [95% CI -0.350, 0.435]). Left ventricle (LV) reverse remodeling assessed by the Teichholz method was underestimated by a mean of 31 mL/m2 (ß = -0.65 [95% CI -1.06 to -0.24], P = .003) compared to Simpson method. CONCLUSION: Compared to the volume-based method, diameter-based LV measurement incorrectly identified LV reverse remodeling post-AVR in 17% of patients with severe AR. Left ventricle (LV) volume may be a better measure to assess LV remodeling post-AVR than LV diameter-based measurements.

Seeking effective interventions to treat complex wounds: an overview of systematic reviews.

BACKGROUND: Numerous, often multi-faceted regimens are available for treating complex wounds, yet the evidence of these interventions is recondite across the literature. We aimed to identify effective interventions to treat complex wounds through an overview of systematic reviews. METHODS: MEDLINE (OVID interface, 1946 until October 26, 2012), EMBASE (OVID interface, 1947 until October 26, 2012), and the Cochrane Database of Systematic Reviews (Issue 10 of 12, 2012) were searched on October 26, 2012. Systematic reviews that examined adults receiving care for their complex wounds were included. Two reviewers independently screened the literature, abstracted data, and assessed study quality using the Assessment of Multiple Systematic Reviews (AMSTAR) tool. RESULTS: Overall, 99 systematic reviews were included after screening 6,200 titles and abstracts and 422 full-texts; 54 were systematic reviews with a meta-analysis (including data on over 54,000 patients) and 45 were systematic reviews without a meta-analysis. Overall, 44% of included reviews were rated as being of high quality (AMSTAR score ≥ 8). Based on data from systematic reviews including a meta-analysis with an AMSTAR score ≥ 8, promising interventions for complex wounds were identified. These included bandages or stockings (multi-layer, high compression) and wound cleansing for venous leg ulcers; four-layer bandages for mixed arterial/venous leg ulcers; biologics, ultrasound, and hydrogel dressings for diabetic leg/foot ulcers; hydrocolloid dressings, electrotherapy, air-fluidized beds, and alternate foam mattresses for pressure ulcers; and silver dressings and ultrasound for unspecified mixed complex wounds. For surgical wound infections, topical negative pressure and vacuum-assisted closure were promising interventions, but this was based on evidence from moderate to low quality systematic reviews. CONCLUSIONS: Numerous interventions can be utilized for patients with varying types of complex wounds, yet few treatments were consistently effective across all outcomes throughout the literature. Clinicians and patients can use our results to tailor effective treatment according to type of complex wound. Network meta-analysis will be of benefit to decision-makers, as it will permit multiple treatment comparisons and ranking of the effectiveness of all interventions. Please see related article: http://dx.doi.org/10.1186/s12916-015-0326-3.

Speckle tracking for the intraoperative assessment of right ventricular function: a feasibility study.

OBJECTIVES: Speckle tracking is an ultrasound method that assesses B-mode features to measure tissue displacement and derive deformation parameters. The objective of this study was to assess the feasibility of using speckle tracking in the measurement of right ventricular (RV) longitudinal strain during cardiac surgery using transesophageal echocardiography (TEE). DESIGN: This was a prospective, observational cohort study. SETTING: A single university hospital setting. PARTICIPANTS: Twenty-one patients without valvular disease referred for coronary artery bypass graft surgery were studied. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: After the induction of anesthesia and mechanical ventilation, transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) were used to obtain tricuspid annular plane systolic excursion (TAPSE), RV fractional area of change (FAC), and 2-dimensional strain analysis (speckle tracking) on 3 consecutive heart beats. There was a larger percentage of measurable segments achieved when using TEE. All segments could be analyzed per cardiac cycle in 73% of loops when using TEE and 38% when using TTE. The global strain value was similar using both methods (TEE: -20.4%, TTE: -20.1%). The TAPSE could be measured in only 52% of the segments using TTE and 100% using TEE. The FAC could be measured in 90.5% of the loops using TEE and in only 33.3% of the loops using TTE. CONCLUSIONS: Perioperative measurements of RV strain using TEE in ventilated patients is feasible. The success rate was higher using TEE in ventilated patients under anesthesia. Differences between the 2 methods were likely the result of differences in 2-dimensional image quality.

Hybrid arch frozen elephant trunk repair: evidence from the Canadian Thoracic Aortic Collaborative.

BACKGROUND: The frozen elephant trunk (FET) technique has become an increasingly popular strategy for aortic reconstruction in the setting of extensive thoracic aortic aneurysms or dissections. The objective of this study is to report on the Canadian experience with the FET technique in both the elective and emergent settings. METHODS: A total of 167 consecutive patients (mean age 65±13 years, 30% female, 25% re-operation) underwent elective (70%) and non-elective (30%) aortic arch reconstruction with the FET technique between May 2008 and October 2019 in six centers of the Canadian Thoracic Aortic Collaborative (CTAC). In-hospital clinical endpoints and early imaging endpoints were prospectively collected and analyzed. RESULTS: All 167 patients underwent successful FET implantation. In-hospital mortality occurred in 14 patients (8%), stroke occurred in 22 patients (13%) and temporary and permanent spinal cord ischemia (SCI) occurred in 6 (3.6%) and 3 (1.8%) patients, respectively. Prolonged mechanical ventilation was required in 35 patients (21%), renal failure requiring dialysis in 14 patients (8%) and atrial fibrillation in 59 patients (36%). The median hospital and intensive care unit (ICU) lengths of stay were 3 [interquartile range (IQR): 1, 6] and 10 (IQR: 7, 17) days, respectively. The rate of type 1A endoleak was 3.6%, with the lowest rate in patients who underwent a total arch replacement with a hybrid FET graft (0%) and the highest among patients who had a hemiarch with antegrade thoracic endovascular aortic repair (TEVAR) deployment (25%). The rate of other types of endoleak and stent complications was comparatively low. CONCLUSIONS: The early CTAC experience with the FET operation demonstrates technical feasibility and good early clinical outcomes in elective and emergent patients. Further analysis is required to explore variations in technique and their potential impact on early and late outcomes.

Innominate and Axillary Cannulation in Aortic Arch Surgery Provide Similar Neuroprotection.

BACKGROUND: Contemporaneous trends in cerebral protection during aortic arch surgery include moderate hypothermia (22°C-28°C) and continuous antegrade cerebral perfusion (ACP). Innominate artery cannulation is a simplified, alternative route for ACP; however, clinical outcomes have yet to be evaluated against the gold standard of axillary cannulation. METHODS: Between 2008 and 2015, 140 consecutive patients underwent hemiarch reconstruction with moderate hypothermia and continuous ACP at 2 institutions. Axillary cannulation was used in 74 patients (31.1% female, 64.8 ± 12.7 years) and the remaining 66 patients (24.2% female, 60.8 ± 10.5 years) had direct cannulation of the innominate artery for delivery of ACP. RESULTS: Although there were no statistically significant differences in complications, neurological events were almost twice as frequent in innominate (19.7%) than in axillary (10.8%; P = 0.142) whereas prolonged mechanical ventilation was much more common with axillary (17.6%) vs innominate (7.6%; P = 0.078). There were no mortalities in the axillary group and 1 in the innominate group (0% vs 1.5%; P > 0.471) and no statistically significant differences in any other postoperative complications or hospital length of stay. There was a reduction in total operating room time in the innominate group (axillary 454 ± 115 minutes, innominate 318 ± 125 minutes; P < 0.001), and in the matched subgroup analysis of patients who underwent Bentall and hemiarch reconstruction (axillary 456 ± 109 minutes, innominate 370 ± 106 minutes; P = 0.003). CONCLUSIONS: Axillary and innominate artery cannulation for ACP during proximal aortic arch reconstructive surgery resulted in similarly excellent neurological outcomes. Innominate artery cannulation might reduce total surgical time. Possible clinically relevant differences in neurological and respiratory complications require assessment in randomized controlled trials.

Safety, effectiveness, and cost effectiveness of long acting versus intermediate acting insulin for patients with type 1 diabetes: systematic review and network meta-analysis.

OBJECTIVE: To examine the safety, effectiveness, and cost effectiveness of long acting insulin for type 1 diabetes. DESIGN: Systematic review and network meta-analysis. DATA SOURCES: Medline, Cochrane Central Register of Controlled Trials, Embase, and grey literature were searched through January 2013. STUDY SELECTION: Randomized controlled trials or non-randomized studies of long acting (glargine, detemir) and intermediate acting (neutral protamine Hagedorn (NPH), lente) insulin for adults with type 1 diabetes were included. RESULTS: 39 studies (27 randomized controlled trials including 7496 patients) were included after screening of 6501 titles/abstracts and 190 full text articles. Glargine once daily, detemir once daily, and detemir once/twice daily significantly reduced hemoglobin A1c compared with NPH once daily in network meta-analysis (26 randomized controlled trials, mean difference -0.39%, 95% confidence interval -0.59% to -0.19%; -0.26%, -0.48% to -0.03%; and -0.36%, -0.65% to -0.08%; respectively). Differences in network meta-analysis were observed between long acting and intermediate acting insulin for severe hypoglycemia (16 randomized controlled trials; detemir once/twice daily versus NPH once/twice daily: odds ratio 0.62, 95% confidence interval 0.42 to 0.91) and weight gain (13 randomized controlled trials; detemir once daily versus NPH once/twice daily: mean difference 4.04 kg, 3.06 to 5.02 kg; detemir once/twice daily versus NPH once daily: -5.51 kg, -6.56 to -4.46 kg; glargine once daily versus NPH once daily: -5.14 kg, -6.07 to -4.21). Compared with NPH, detemir was less costly and more effective in 3/14 cost effectiveness analyses and glargine was less costly and more effective in 2/8 cost effectiveness analyses. The remaining cost effectiveness analyses found that detemir and glargine were more costly but more effective than NPH. Glargine was not cost effective compared with detemir in 2/2 cost effectiveness analyses. CONCLUSIONS: Long acting insulin analogs are probably superior to intermediate acting insulin analogs, although the difference is small for hemoglobin A1c. Patients and their physicians should tailor their choice of insulin according to preference, cost, and accessibility. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42013003610.

Complete mapping of the tricuspid valve apparatus using three-dimensional sonomicrometry.

OBJECTIVE: Many surgeons consider the tricuspid valve to be a second-class structure. Our objective was to determine the normal anatomy and dynamic characteristics of the tricuspid valve apparatus in vivo and to discern whether this would aid the design of a tricuspid valve annuloplasty ring model. METHODS: Sixteen sonomicrometry crystals were placed around the tricuspid annulus, at the bases and tips of the papillary muscles, the free edges of the leaflets, and the right ventricular apex during cardiopulmonary bypass in 5 anesthetized York Hampshire pigs. Animals were studied after weaning of cardiopulmonary bypass on 10 cardiac cycles of normal hemodynamics. RESULTS: Sonomicrometry array localizations demonstrate the multiplanar shape of the tricuspid annulus. The tricuspid annulus reaches its maximum area (97.9 ± 25.4 mm(2)) at the end of diastole and its minimum area (77.3 ± 22.5 mm(2)) at the end of systole, and increases again in early diastole. Papillary muscles shorten by 0.8 to 1.5 mm (11.2%) in systole, and chordae tendineae straighten by 0.8 to 1.7 mm (11.4%) in systole. CONCLUSIONS: The shape of the tricuspid annulus is a multiplanar 3-dimensional one with its highest point at the anteroseptal commissure and its lowest point at the posteroseptal commissure, and the anteroposterior commissure is in a middle plane in between. The tricuspid annulus area reaches its maximum during diastole and its minimum during systole. The papillary muscles contract by the same amount of chordal straightening. The optimal tricuspid annuloplasty ring may be a multiplanar 3-dimensional one that mimics the normal tricuspid annulus.

Sternal plating for primary and secondary sternal closure; can it improve sternal stability?

BACKGROUND: Sternal instability with mediastinitis is a very serious complication after median sternotomy. Biomechanical studies have suggested superiority of rigid plate fixation over wire cerclage for sternal fixation. This study tests the hypothesis that sternal closure stability can be improved by adding plate fixation in a human cadaver model. METHODS: Midline sternotomy was performed in 18 human cadavers. Four sternal closure techniques were tested: (1) approximation with six interrupted steel wires; (2) approximation with six interrupted cables; (3) closure 1 (wires) or 2 (cables) reinforced with a transverse sternal plate at the sixth rib; (4) Closure using 4 sternal plates alone. Intrathoracic pressure was increased in all techniques while sternal separation was measured by three pairs of sonomicrometry crystals fixed at the upper, middle and lower parts of the sternum until 2.0 mm separation was detected. Differences in displacement pressures were analyzed using repeated measures ANOVA and Regression Coefficients. RESULTS: Intrathoracic pressure required to cause 2.0 mm separation increased significantly from 183.3 +/- 123.9 to 301.4 +/- 204.5 in wires/cables alone vs. wires/cables plus one plate respectively, and to 355.0 +/- 210.4 in the 4 plates group (p < 0.05). Regression Coefficients (95% CI) were 120 (47-194) and 142 (66-219) respectively for the plate groups. CONCLUSION: Transverse sternal plating with 1 or 4 plates significantly improves sternal stability closure in human cadaver model. Adding a single sternal plate to primary closure improves the strength of sternal closure with traditional wiring potentially reducing the risk of sternal dehiscence and could be considered in high risk patients.

Increased cerebral and renal endothelial nitric oxide synthase gene expression after cardiopulmonary bypass in the rat.

OBJECTIVE: Hemodilution and endothelial nitric oxide synthase genetic polymorphism may contribute to cerebral and renal injury after cardiopulmonary bypass. This study tested the hypothesis that cardiopulmonary bypass and anemia stimulate an increase in cerebral and renal endothelial nitric oxide synthase gene expression in an experimental model of cardiopulmonary bypass. METHODS: Anesthetized rats underwent a sham procedure without cardiopulmonary bypass (sham, n = 5), normothermic bypass for 1 hour (CPB, n = 7), or bypass plus hemodilutional anemia (CPB anemia, n = 9). After 24 hours of recovery, RNA was extracted from the cerebral cortex, renal cortex, and renal medulla. Quantitative reverse transcriptase polymerase chain reaction was used to assess endothelial nitric oxide synthase messenger RNA levels in brain and kidney tissues. RESULTS: The hemoglobin concentration of anemic CPB rats was significantly lower than that of nonanemic rats on bypass (64 +/- 5 vs 99 +/- 8 g x L(-1), P < .001). Cerebral cortical endothelial nitric oxide synthase messenger RNA levels were increased after cardiopulmonary bypass relative to those of the sham group (11.2 +/- 4.2 vs 6.3 +/- 1.5 fg, P = .031), without a further increase in anemic rats. Renal medullary endothelial nitric oxide synthase messenger RNA levels were significantly higher in the CPB anemia group than in the sham and CPB groups (7.1 +/- 4.4 fg vs 1.8 +/- 0.4 fg vs 3.0 +/- 0.6 fg, P < .001). Renal cortical endothelial nitric oxide synthase messenger RNA levels did not change significantly. CONCLUSIONS: Normothermic cardiopulmonary bypass was associated with higher endothelial nitric oxide synthase messenger RNA levels in kidney and brain than was the sham procedure 24 hours after cardiopulmonary bypass. Anemia accentuated the increase in renal medullary, but not cerebral cortical, endothelial nitric oxide synthase expression. These data provide an approach for exploring potential mechanisms by which endothelial nitric oxide synthase may contribute to renal and cerebral dysfunction after cardiopulmonary bypass and anemia.

Effect of oxygen affinity and molecular weight of HBOCs on cerebral oxygenation and blood pressure in rats.

PURPOSE: This study assessed the effect of oxygen affinity and molecular weight (MW) of o-raffinose cross-linked hemoglobin based oxygen carriers (HBOCs) on cerebral oxygen delivery and mean arterial blood pressure (MAP) following hemorrhage and resuscitation in rats. METHODS: Isoflurane anesthetized rats (n = 6-7 per group) underwent 30% hemorrhage and resuscitation with an equivalent volume of one of three different HBOCs: 1) High P50 Poly o-raffinose hemoglobin (Poly OR-Hb, P50 = 70 mmHg); 2) High P50 > 128 Poly OR-Hb (MW > 128 kDa, P50 = 70 mmHg) and 3) Low P50 > 128 Poly OR-Hb (MW >128 kDa, P50 = 11 mmHg). Hippocampal cerebral tissue oxygen tension, regional cerebral blood flow (rCBF), MAP, total hemoglobin concentration and arterial blood gases were measured. Data analysis by two-way ANOVA and post hoc Tukey tests determined significance (P < 0.05, mean +/- SD). RESULTS: Hippocampal tissue oxygen tension increased in all HBOC groups following resuscitation. The rCBF remained unchanged after HBOC resuscitation in all groups. Following resuscitation, the peak MAP was higher in the High P50 Poly OR-Hb group (152 +/- 13 mmHg) when compared to either the Low or High P50 large MW, (> 128 kDa) HBOC group (119 +/- 15 mmHg or 127 +/- 18 respectively, P < 0.05 for both). CONCLUSIONS: O-raffinose polymerized HBOC, with or without lower MW components, maintained cerebral tissue oxygen delivery following hemorrhage and resuscitation in rats. The higher MW HBOCs showed a decrease in peak MAP, which did not alter oxygen delivery. No significant effect of oxygen affinity on cerebral tissue oxygen tension or blood flow was observed.