Reduced arterial elasticity due to surgical skeletonization is ameliorated by abluminal PEG hydrogel.

Arteries for bypass grafting are harvested either with neighboring tissue attached or as skeletonized vessels that are free of surrounding tissue. There are significant benefits to skeletonization, but reports suggest that skeletonized vessels may develop structural defects and are at risk for atherosclerosis. We investigated the specific short-term effects of skeletonization on carotid artery biomechanics and microanatomy in a rabbit model. Six carotid arteries were surgically skeletonized. To support healing, three of these received polyethylene glycol hydrogel injected along their exterior surfaces. M-mode ultrasonography was used to track circumferential cyclic strain in the skeletonized, hydrogel-treated, and contralateral vessels. On day 21, the arteries were harvested, and vessel structure was assessed by histology, immunofluorescence microscopy, two-photon elastin autofluorescence, and second harmonic generation (SHG) microscopy. Intimal-medial thickness appeared unaffected by skeletonization, but the SHG signals indicated significant changes in collagen turnover in the adventitia. Skeletonized arteries also exhibited significantly decreased radial compliance (circumferential cyclic strain dropped ∼30%) and decreased numbers of elastic laminae (9.1 ± 2.0 to 2.3 ± 1.4). Hydrogel treatment protected against these effects with treated vessels maintaining normal mechanical properties. These results indicate that arterial skeletonization triggers immediate effects on vessel remodeling and reduced vessel compliance resulting in specific tissue alterations within 21 days, but that these effects can be attenuated by the placement of hydrogel on the exterior surface of the skeletonized vessel.

Left-Sided Reoperations After Arterial Switch Operation: A European Multicenter Study.

BACKGROUND: We sought to report the frequency, types, and outcomes of left-sided reoperations (LSRs) after an arterial switch operation (ASO) for patients with D-transposition of the great arteries (D-TGA) and double-outlet right ventricle (DORV) TGA-type. METHODS: Seventeen centers belonging to the European Congenital Heart Surgeons Association (ECHSA) contributed to data collection. We included 111 patients who underwent LSRs after 7,951 ASOs (1.4%) between January 1975 and December 2010. Original diagnoses included D-TGA (n = 99) and DORV TGA-type (n = 12). Main indications for LSR were neoaortic valve insufficiency (n = 52 [47%]) and coronary artery problems (CAPs) (n = 21 [19%]). RESULTS: Median age at reoperation was 8.2 years (interquartile range [IQR], 2.9-14 years). Seven patients died early after LSRs (6.3%); 4 patients with D-TGA (5.9%) and 3 patients with DORV TGA-type (25%) (p = 0.02). Median age at last follow-up was 16.1 years (IQR, 9.9-21.8 years). Seventeen patients (16%) required another reoperation, which was more frequent in patients with DORV- TGA type (4 of 9 [45%]) than in patients with D-TGA (13 of 95 [14%]). Late death occurred in 4 patients (4 of 104 [3.8%]). The majority of survivors were asymptomatic at last clinical examination (84 of 100 [84%]). CONCLUSIONS: Reoperations for residual LSRs are infrequent but may become necessary late after an ASO, predominantly for neoaortic valve insufficiency and CAPs. Risk at reoperation is not negligible, and DORV TGA-type anatomy, as well as procedures on the coronary arteries, were significantly associated with a higher morbidity and a lower overall survival. Recurrent reoperations after LSRs may be required.

Improving early outcomes following hybrid procedure for patients with single ventricle and systemic outflow obstruction: defining risk factors†.

OBJECTIVES: The hybrid procedure has become an accepted management strategy for patients with single ventricle and systemic outflow obstruction (SVSOO), particularly those considered at high risk for mortality following Stage I Norwood. We sought to refine patient selection by identifying clinical variables associated with early mortality. METHODS: Single-centre review of all patients with SVSOO undergoing a hybrid procedure between January 2003 and December 2012. Demographic, clinical and outcome data were collected from the electronic medical record. The primary outcome was operative mortality (mortality within 30 days of the operation or prior to hospital discharge). RESULTS: Thirty-four patients underwent hybrid palliation at a median age of 5 days (IQR 3-8.5) and a median weight of 2.5 kg (IQR 2.2-2.9). Aortic atresia was present in 13 of 34 patients. Emergency banding for resuscitation was performed in 8 cases. Subsequent procedures included Stage I Norwood in 14, combined Stage I and II Norwood in 8, biventricular repair in 3 and cardiac transplantation in 2. Median cardiac intensive care unit length of stay was 54 days (IQR 27-92). Seven patients had no subsequent procedure. There were 11 operative deaths. Non-modifiable patient-related factors had a significant association with operative mortality, including weight under 2.0 kg (OR 18; 95% CI 1.8-188.3, P = 0.0008) and aortic atresia (OR 6.1; 95% CI 1.2-30.1, P = 0.026). Most significant was the interaction between aortic atresia and weight under 2.0 kg on early mortality (OR 13.1; 95% CI 1.9-92 P = 0.0039). The multivariate analysis demonstrated that the presence of aortic atresia (OR 13.4; 95% CI 1.2-151) and a birthweight of 2.0 kg or less (OR 51; 95% CI 2.4-999) were also significant predictors of operative mortality. CONCLUSIONS: Non-modifiable patient-related factors have a profound effect on early survival following a hybrid procedure for SVSOO. Outcomes for patients under 2.0 kg with aortic atresia remain very poor. Risk stratification should inform management decisions.

Hybrid palliation for critical systemic outflow obstruction: neither rapid stage 1 Norwood nor comprehensive stage 2 mitigate consequences of early risk factors.

OBJECTIVE: Hybrid palliation with branch pulmonary artery banding (bPAB) has become increasingly common in the early management of patients with critical left ventricular outflow obstruction. Optimal subsequent surgical palliation remains undefined. METHODS: We retrospectively reviewed patients undergoing initial bPAB for single ventricle physiology with systemic outflow obstruction (2001-2013, n = 37). Patients were stratified by subsequent surgical palliation: stage 1 Norwood (St1N, n = 14), comprehensive stage 2 (CompSt2, n = 11), and none (n = 12). RESULTS: bPAB was performed at a median of 4 days and 2.7-kg, post-bPAB mortality was increased in patients with aortic atresia (odds ratio [OR] = 3.8, 95% confidence interval [CI] = 0.9-15.8) or birth weight <2 kg (OR = 13.8, 95% CI = 1.4-136.4). Palliation strategy did not affect transplant-free survival through second-stage palliation (St1N: 71.4%, CompSt2: 72.7%, P = .9). Among CompSt2 patients, there was a trend toward poorer survival with aortic atresia (0% vs 80%, P = .09); birth weight <2.5 kg was associated with decreased survival (0% vs 89.0%, P = .01). A trend toward lower survival with low birth weight was evident among St1N patients (<2 kg, OR = 0.1, 95% CI = 0.01-1.9, P = .09). CompSt2 mortality occurred on postoperative days 0 and 1. Mortality following St1N occurred at a median of 38.5 days (range = 23.5-104.5). Among survivors of stage 2 palliation, Fontan completion was performed in the same number of patients in each group (St1N: 6/8, 75%, CompSt2: 6/8, 75%). CONCLUSIONS: Both St1N and CompSt2 are viable options for subsequent palliation following initial hybrid procedure. Transplant-free survival and eventual Fontan candidacy are similar between groups. Delaying surgical palliation with the CompSt2 did not mitigate the impact of early risk factors such as low birth weight and aortic atresia.

Neurodevelopmental outcomes after infant cardiac surgery with circulatory arrest and intermittent perfusion.

BACKGROUND: Optimal perfusion strategies for neuroprotection during infant cardiac surgery remain undefined. Despite encouraging experimental data, neurodevelopmental (ND) outcomes after cardiac surgery in neonates and infants using deep hypothermic circulatory arrest (DHCA) with a period of intermittent perfusion have not been reported, and it is not known whether DHCA can be extended while preserving ND outcomes. METHODS: Cross-sectional ND evaluation with the Bayley Scales of Infant and Toddler Development, Third Edition was conducted at 24 months of age. Retrospective clinical data were extracted from the electronic medical record. RESULTS: Forty patients underwent cardiac surgery during the first year of life using a period of uninterrupted DHCA (24 patients) or DHCA interrupted by a period of intermittent perfusion (16 patients). Total duration of DHCA ranged from 5 to 74 minutes and did not predict ND scores. Despite a longer exposure to DHCA in the intermittent perfusion group (55 minutes [1,3 interquartile [IQ] 45.3 to 65.5] versus 38 minutes [1,3 IQ 32 to 40.8]), no differences in ND scores were detected. Significant comorbidities, duration of intensive care unit and hospital stay, as well as multiple procedures with DHCA were independent predictors of ND outcomes at 24 months of age. CONCLUSIONS: Despite extended duration of total DHCA, the use of a period of intermittent perfusion to limit uninterrupted DHCA periods to less than 45 minutes could lead to ND outcomes similar to those of patients exposed to brief periods of DHCA. Deep hypothermic circulatory arrest with intermittent perfusion may facilitate implementation of prospective studies to identify the optimal cerebral perfusion strategy.

Predictive value of perioperative near-infrared spectroscopy for neurodevelopmental outcomes after cardiac surgery in infancy.

OBJECTIVE: The study objective was to expand on prior research examining intraoperative regional cerebral oxygen saturation (rSO(2)) measured by near-infrared spectroscopy (NIRS) by evaluating the predictive value of perioperative NIRS monitoring for neurodevelopmental outcomes after infant cardiac surgery. METHODS: Cross-sectional neurodevelopmental evaluation at 24 months of age with the Bayley Scales of Infant and Toddler Development, Third Edition was performed for patients who underwent cardiac surgery with perioperative NIRS monitoring between 2007 and 2010. Retrospective clinical data were extracted from the electronic medical record. Evaluation of selected NIRS measures, including preoperative rSO(2) (baseline) as well as rSO(2) nadir and percent decrease from baseline during the intraoperative and early postoperative periods, was undertaken. RESULTS: Perioperative NIRS and neurodevelopmental data were available for 31 patients without chromosomal anomalies who underwent cardiac surgery during infancy at a median age of 0.43 months. Optimal thresholds on NIRS measures identified through receiver operating characteristic analyses were intraoperative percent decrease of 52% for receptive communication delay and postoperative rSO(2) nadir of 56% for cognitive delay and 49% for gross motor delay. When considered in conjunction with other clinical characteristics in stepwise linear regression analyses, intraoperative percent decrease of more than 52% entered into the final model for receptive communication outcome and postoperative rSO(2) nadir of less than 56% entered into the final model for cognitive outcome. CONCLUSIONS: Perioperative NIRS monitoring seems to enhance the ability to predict neurodevelopmental outcome. Specific NIRS measures associated with neurodevelopmental outcome, as well as optimal thresholds, seem to differ across the continuum of the perioperative period.

Inflammation effects on the electrical properties of atrial tissue and inducibility of postoperative atrial fibrillation.

BACKGROUND: Atrial fibrillation is the most common complication after cardiac surgery. Postoperative atrial fibrillation (PAF) has been shown to increase length of stay, morbidity, and mortality. Because the clinical behavior of PAF parallels that of inflammation following surgery, we investigated the effect of the inflammatory mediator arachidonic acid on the electrical behavior of normal atrial tissue in vitro and assessed the efficacy of the topical application of anti-inflammatory drugs at suppressing PAF in an animal model. METHODS: To study changes in electrical behavior from inflammation, the conduction properties of six normal canine right atrial appendages were quantified as a function of the direction of impulse propagation with and without 80 mum arachidonic acid. To study the effect of topical anti-inflammatory drugs, 24 adult mongrel dogs were prepared according to the model of sterile talc pericarditis. Nine dogs received talc alone (T), seven received talc combined with 600 mg ibuprofen (T + I), and eight received talc combined with 10 mg methylprednisolone (T + M). Three days following preparation, programmed electrical stimulation was performed to quantify conduction characteristics and to attempt the induction of atrial fibrillation (AF). RESULTS: In vitro, arachidonic acid produced an anisotropic and rapidly reversible 36.1 +/- 3.4% (P = 0.01) decrease in conduction velocity transverse to the long axis only. In vivo, both ibuprofen and methylprednisolone significantly reduced the incidence of sustained AF (from 56 to 0% T + I and 12% T + M, respectively, P = 0.02). No differences in conduction velocities or refractory periods were seen during sinus rhythm among the groups. CONCLUSIONS: Acute inflammation as mimicked by arachidonic acid slows conduction anisotropically, mainly transverse to the long axis of the atrial myocardial fibers. This may set the stage for reentry. Preventing inflammation in vivo by the topical application of anti-inflammatory drugs supports this hypothesis, suggesting a possible role for inflammation in the genesis of postoperative atrial fibrillation and shedding light on the mechanism underlying PAF.