Faculty Bibliography

Diffuse alveolar hemorrhage (DAH) from systemic lupus erythematosus (SLE) is a rare but potentially life-threatening condition. We report the case of a 14-year-old female with SLE who developed hypoxia and shock secondary to severe alveolar hemorrhage. She was successfully managed by placement on extracorporeal membrane oxygenation (ECMO) followed by emergent pulmonary lobectomy and medical treatment including high-dose methylprednisolone, cyclophosphamide, intravenous immunoglobulin, and plasmapheresis.

OBJECTIVE:The optimal timing for neonatal cardiac surgery is unknown. We aimed to determine the relationship between age at surgery and perioperative outcomes, hypothesizing that earlier intervention would be associated with lower morbidity and mortality. METHODS:A retrospective review was performed of neonates who had undergone an arterial switch operation, stage 1 palliation for functional single ventricle, or systemic-to-pulmonary shunt for obstructed pulmonary blood flow from January 1, 2005, to December 31, 2010. The subjects with clinical indications for delayed surgery or prematurity were excluded. Age at surgery was evaluated as both a continuous and a categorical variable. The primary outcome was a composite endpoint of mortality or prolonged intensive care stay. RESULTS:Of 344 subjects, 286 (77 arterial switch operation, 124 stage 1 palliation, 85 systemic-to-pulmonary shunt) met the inclusion criteria. In each group, age at surgery was not associated with the primary composite endpoint. The patients who died after systemic-to-pulmonary shunt had a median age at surgery of 3 days versus 6 days for the survivors (P = .04). A similar, but nonsignificant, pattern was seen for patients undergoing arterial switch operations (4.5 vs 7 days; P = .09). Earlier surgery was not associated with a reduced duration of vasoactive support, mechanical ventilation, or intensive care unit length of stay in any group. Stage 1 palliation subjects in the upper age quartile (≥8 days) at surgery were less likely to require prolonged mechanical ventilation (P = .03). CONCLUSIONS:Younger age at intervention in the neonatal period was not associated with reduced morbidity or mortality in any procedural subgroup studied. In our cohort, earlier systemic-to-pulmonary shunt for obstructed pulmonary blood flow was associated with a greater likelihood of a poor outcome.

OBJECTIVE:Junctional ectopic tachycardia complicates the postoperative recovery from open heart surgery in children. The reported risk factors include younger age, prolonged cardiopulmonary bypass times, and administration of inotropic agents. Junctional ectopic tachycardia occurs early after open heart surgery, in the setting of relative postoperative sinus node dysfunction, and exhibits QRS morphology consistent with an origin from the atrioventricular node or proximal conduction system. Our goal was to develop a reproducible animal model for postoperative junctional ectopic tachycardia. METHODS:Eleven pigs, aged 2 to 4 months, underwent open heart surgery after induction of general anesthesia. Electrodes were sewn to the left atrium and right ventricle. RESULTS:Sinus node dysfunction was created using clamp crushing without or with radiofrequency ablation (successful in 1 of 5 pigs) or sinus node removal (successful in 4 of 4). After prolonged cardiopulmonary bypass (>120 minutes) alone and with isoproterenol infusion, no spontaneous junctional ectopic tachycardia developed. Junctional ectopic tachycardia or fascicular tachycardia could be initiated after either slow atrioventricular nodal pathway ablation and/or digoxin administration. Junctional ectopic tachycardia occurred in 8 of 9 pigs (mean ventricular rate, 171 ± 32 bpm), and fascicular tachycardia occurred in 9 of 9 pigs (mean ventricular rate, 187 ± 39 bpm). His and right bundle recordings confirmed the conduction system origin. CONCLUSIONS:Experimental junctional ectopic tachycardia or fascicular tachycardia can occur in the intraoperative setting of sinus node dysfunction, prolonged cardiopulmonary bypass, and enhanced conduction system automaticity. Conduction system automaticity occurred after either physical injury (ablation or tricuspid valve stretch) or measures to augment the transient inward current of the conduction system (isoproterenol and digoxin). This animal model can serve as the basis to assess new treatments of postoperative junctional ectopic tachycardia.

OBJECTIVE:Our objective was to evaluate the effects of glutaraldehyde (GA) concentration, time of pretreatment, and type of tissue (porcine vs bovine) on quantitative and qualitative postimplant calcification of tissues. METHODS:Freshly obtained porcine and bovine pericardial tissues were each treated with increasing concentrations of GA (controls, 0.3125%, 0.625%, and 1.2%) for a fixed time (15 minutes) or increasing exposure times (5, 10, 20, and 30 minutes) at a fixed concentration of GA (0.625%). Pretreated tissues were subcutaneously implanted in 10-week-old Sprague-Dawley rats for 45 days before explantation. Quantitative calcium analysis was performed by flame atomic spectrophotometry. Histologic examination of tissue samples with hematoxylin and eosin and von Kossa staining was performed for cellular and inflammatory response, autolysis, and calcification. RESULTS:Two-way analysis of variance indicated significantly greater calcium levels at 1.2% compared with each lower concentration for both porcine and bovine samples (P < .01). Significantly lower calcium levels were detected with increased exposure time in porcine samples (F = 6.97; P < .001); however, no significant differences in calcium levels were observed between different exposure times for bovine samples (F = 1.46; P = .23). Histologic evidence of inflammatory response with infiltration with mononuclear cells, fibroblasts, and histiocytes was seen in all grafts; however, it varied from mild to severe without any pattern. There were no differences in degree or pattern of inflammatory response according to GA concentration or time of exposure. Estimation of amount of calcification by histologic examination correlated with the quantitative assay. CONCLUSIONS:Increasing GA concentration leads to greater calcification with a sharp rise in calcium levels above a concentration of 0.625%, in both bovine and porcine pericardial tissues. At a concentration of 0.625%, increasing pretreatment time is inversely related to tissue calcification for porcine pericardium but not for bovine pericardium. Differences in the tissue composition in terms of cellular content and composition of the extracellular matrix could account for the observed findings.

OBJECTIVE:Blood pressure gradients that are noted early after repair of coarctation in neonates and infants are often attributed to proximal arch hypoplasia. Rapid growth of the hypoplastic proximal arch is usually observed, although in some individuals an early gradient predicts the subsequent need for reintervention. To define the predictive reliability of blood pressure gradients between arms and legs and to identify predictors of arch growth, we undertook a retrospective study. METHODS:Between January 2000 and June 2008, 77 infants underwent surgical repair of coarctation. Data collected included preoperative dimensions of aortic segments. Blood pressure gradients between arms and legs determined by cuff were compared intraoperatively and postoperatively, as well as 2-dimensional echocardiographic dimensions of the aorta between those who did not require reintervention for recoarctation (group A) and those who did (group B). Receiver operating characteristic curve analysis was applied to evaluate discrimination of the systolic gradient in differentiating the 2 groups of patients. RESULTS:At surgery, patients' median age was 10 days and weight was 3.3 kg. There was 1 early death. Median follow-up was 40 months (interquartile range, 24-63 months). Recoarctation developed in 11 patients (14.3%), defined as a resting blood pressure gradient of greater than 20 mm Hg with a corresponding decrease in the diameter of the aorta by 50%. Freedom from recoarctation was 87% at 1 year and 85% at 5 years. Multivariable logistic regression analysis identified the size of the ascending aorta as a risk factor for recoarctation. Blood pressure gradient at the end of surgery was not predictive of recoarctation. The ascending aorta and transverse arch showed rapid growth in group A, and this was associated with a decrease in blood pressure gradient over time. In comparison, the growth of the ascending aorta and arch in group B was significantly less than in group A and associated with worsening of gradients. Receiver operating characteristic curve analysis revealed that gradients at the time of hospital discharge (>13 mm Hg) had excellent discriminative accuracy in identifying patients in whom subsequent recoarctation developed. CONCLUSIONS:Small size of the ascending aorta is a risk factor for recoarctation. Limb gradient in the operating room at completion of surgery is not a reliable tool to assess repair of coarctation, although the gradient at the time of hospital discharge can be used to accurately predict recoarctation. Rapid growth of both the ascending and the transverse aorta is frequently observed and associated with improvement in gradients over time.