Matthew Buelow

Urinary interleukin-18 and urinary neutrophil gelatinase-associated lipocalin predict acute kidney injury following pulmonary valve replacement prior to serum creatinine.

BACKGROUND It is becoming increasingly recognized that manifestations of congenital heart disease (CHD) extend beyond the cardiovascular system. The factors contributing to renal dysfunction in patients with CHD are multifactorial, with acute kidney injury (AKI) at time of cardiac surgery playing a major role. AKI is often diagnosed based on changes in serum creatinine and estimated glomerular filtration rate (eGFR). Such measurements are often late and imprecise. Recent data indicate that urinary biomarkers interleukin-18 (IL-18) and neutrophil gelatinase-associated lipocalin (NGAL) are earlier markers of AKI. We sought to determine the efficacy of urinary IL-18 and NGAL for detecting early AKI in patients undergoing surgical pulmonary valve replacement (PVR). METHODS Twenty patients presenting for surgical PVR with a history of previous repair of a conotruncal anomaly were enrolled. Preoperative clinical data were measured and urine samples and serum creatinine were collected at 6, 12, 24, and 72 hours post bypass. Urine was evaluated for NGAL and IL-18. AKI was determined using the Risk, Injury, Failure, Loss and End Stage Renal Disease (RIFLE) classification system. RESULTS Using the RIFLE classification system, seven patients (35%) were found to have AKI defined as a drop in the eGFR or an increase in serum creatinine. All seven patients with AKI had marked increase from preoperative baseline in urine IL-18 (sixfold) and NGAL (26-fold). Using NGAL and IL-18, AKI was detected at 6 hours postoperatively, resulting in AKI being identified 12-36 hours prior to detection by conventional methods. No preoperative predictors for AKI were identified. CONCLUSION Both NGAL and IL-18 are early predictive biomarkers of AKI, and both increase in tandem after surgical PVR. Importantly, both rise before an increase in creatinine or a decrease in eGFR is present. Monitoring both biomarkers may allow for earlier detection and subsequent interventions to prevent AKI at time of surgery for CHD.

Reduced angiotensin II levels cause generalized vascular dysfunction via oxidant stress in hamster cheek pouch arterioles

OBJECTIVES We investigated the effect of suppressing plasma angiotensin II (ANG II) levels on arteriolar relaxation in the hamster cheek pouch. METHODS Arteriolar diameters were measured via television microscopy during short-term (3-6days) high salt (HS; 4% NaCl) diet and angiotensin converting enzyme (ACE) inhibition with captopril (100mg/kg/day). RESULTS ACE inhibition and/or HS diet eliminated endothelium-dependent arteriolar dilation to acetylcholine, endothelium-independent dilation to the NO donor sodium nitroprusside, the prostacyclin analogs carbacyclin and iloprost, and the KATP channel opener cromakalim; and eliminated arteriolar constriction during KATP channel blockade with glibenclamide. Scavenging of superoxide radicals and low dose ANG II infusion (25ng/kg/min, subcutaneous) reduced oxidant stress and restored arteriolar dilation in arterioles of HS-fed hamsters. Vasoconstriction to topically-applied ANG II was unaffected by HS diet while arteriolar responses to elevation of superfusion solution PO2 were unaffected (5% O2, 10% O2) or reduced (21% O2) by HS diet. CONCLUSIONS These findings indicate that sustained exposure to low levels of circulating ANG II leads to widespread dysfunction in endothelium-dependent and independent vascular relaxation mechanisms in cheek pouch arterioles by increasing vascular oxidant stress, but does not potentiate O2- or ANG II-induced constriction of arterioles in the distal microcirculation of normotensive hamsters.

Comparison of Contrast Volume, Radiation Dose, Fluoroscopy Time, and Procedure Time in Previously Published Studies of Rotational Versus Conventional Coronary Angiography

Conventional coronary angiography (CA) with static imaging is limited by the ability to properly select the optimal acquisition angle, vessel foreshortening, and significant radiation exposure. Rotational coronary angiography (RA) acquires coronary images in a multitude of viewing angles during a single injection by means of a moving gantry that rapidly completes a predefined arc. This study compares procedural characteristics of CA and RA. Electronic search of databases such as OVID, Medline, and PubMed was conducted to identify studies comparing procedural characteristics of CA and RA. End points for analysis included contrast volume, radiation dose by dose area product, radiation dose by air kerma, fluoroscopy time, and procedure time. Studies were assessed for quality and bias and were included if they compared coronary imaging of both the right and left coronary systems with CA and RA, included one of the end points of interest, and were in English. A total of 11 studies consisting of 940 patients who underwent RA and 976 who underwent CA were included in the final analysis. Contrast volume, radiation dose by dose area product, and radiation dose by air kerma were all found to be significantly lower with RA compared with CA. There was a statistically significant increase in fluoroscopy time, although this was not clinically significant, and there was no difference in procedure time. RA angiography is a feasible alternative to CA and offers reductions in contrast used and radiation exposure.

Hemodynamic Profile of Acute Kidney Injury Following the Fontan Procedure: Impact of Renal Perfusion Pressure:

Background: Acute kidney injury (AKI) is common following cardiopulmonary bypass. Fontan completion may result in systemic venous hypertension and low cardiac output, reducing renal perfusion pressure (RPP) and further increasing the risk of AKI. We investigated the incidence and risk factors for post-Fontan AKI. Methods: Single-center retrospective study of children undergoing Fontan completion from 2005 to 2012. Demographic and hemodynamic variables were assessed for association with AKI. Subgroup analysis was performed on patients with high-grade AKI (creatinine increase of ≥2.0 × baseline). Vital sign data were collected hourly for the first postoperative day. Results: A total of 186 patients underwent Fontan at 3.1 (2.5-3.8) years of age and 13.5 kg (12.2-15.1). Acute kidney injury occurred in 97 (52%) patients, with high-grade AKI in 52 (28%). Univariate analysis identified reduced RPP in patients with AKI compared to those without AKI, 50 (45-56) mm Hg versus 58 (54-61) mm Hg (P < .0001), due to lower mean arterial blood pressure, 63 (60-69) versus 70 (66-73) mm Hg (P < .0001), and higher central venous pressure, 14 (12-16) versus 13 (11-14) mm Hg, (p < .0001). Multivariable logistic regression and classification tree analyses further identified elements of RPP as significant predictors of AKI, especially high-grade AKI. Postoperative intubation was linked to AKI development. Patients with AKI had decreased postoperative urine output with increased colloid requirements, duration of chest tube insertion, and hospital length of stay. Conclusion: Acute kidney injury occurs frequently following the Fontan procedure. Associated factors include reduced RPP, high colloid requirements, and postoperative intubation. Targeted hemodynamic interventions may serve to reduce the incidence of post-Fontan AKI.

Complete Repair of Tetralogy of Fallot in the Neonatal Versus Non-neonatal Period: A Meta-analysis

It is unclear if neonatal tetralogy of Fallot repair offers better outcomes compared to repair later in infancy. We therefore conducted a meta-analysis comparing outcomes of neonatal and non-neonatal repair. Manuscripts were identified and reviewed for quality and bias with favorably scored manuscripts being included in the final meta-analysis. Several perioperative and postoperative variables were compared. A total of 8 studies with 3858 patients were included in the analysis. Of these patients, 19% underwent neonatal repair. Neonatal repair was associated with increased mortality, longer intensive care unit stays, and longer total hospital length of stay.

The Impact of Obesity on Postoperative Outcomes in Adults with Congenital Heart Disease Undergoing Pulmonary Valve Replacement

OBJECTIVE The impact of obesity on surgical morbidity in adults with congenital heart disease is currently unknown. The aim of our study was to investigate the impact of obesity on postoperative outcomes in adults with congenital heart disease undergoing reoperation for pulmonary valve replacement. METHODS A retrospective analysis was performed assessing the influence of obesity on surgical outcomes. Obesity was defined as a body mass index ≥30 kg/m2. RESULTS The mean body mass index of the cohort was 25.9 ± 6.9 kg/m2 . The cohort included 71 patients with 17 patients (24%) being obese. There was no postoperative mortality. Obese patients had a longer hospital length of stay (6.6 vs. 4.7 days; P < .001) and increased incidence of postoperative arrhythmias (29% vs. 5.6%; P = .003) compared with nonobese patients. Multivariable analysis performed using logistic regression with backwards elimination demonstrated obesity was independently associated with hospital length of stay >5 days (odds ratio [OR] = 5.2; 95% confidence interval [CI]: 1.5-18.2, P = .01) and with increased postoperative arrhythmias (OR = 4.2; 95% CI: 1.7-40, P < .01). CONCLUSIONS Obesity is associated with increased morbidity in adults with congenital heart disease undergoing pulmonary valve replacement, including longer hospitalization and higher risk for postoperative arrhythmias.

Forced vital capacity predicts morbidity and mortality in adults with repaired tetralogy of Fallot

OBJECTIVE Abnormal lung function characterized by a reduced forced vital capacity (FVC) is common in adults with repaired tetralogy of Fallot (TOF) and is associated with previous thoracotomies and sternotomies. The impact of abnormal lung function on clinical outcomes in adult patients with repaired TOF is unclear. The aim of this study was to determine the impact of abnormal lung function on the outcome of hospitalization and death in adults with repaired TOF when analyzed with other traditional cardiac risk factors. DESIGN Retrospective study of adults with repaired TOF, who underwent spirometry between 2000 and 2014. FVC < 60% of predicted was categorized as moderate-to-severely reduced lung function. Primary outcome measure was the combined clinical endpoint of death, cardiac transplantation, or nonelective hospitalization for primary cardiac or respiratory indication. RESULTS A total of 122 patients were included. Average age at spirometry testing was 31 ± 10.1 years. FVC was < 60% predicted in 23 (19%) patients. During a mean follow-up period of 3.97 ± 2.65 years, 23 (19%) patients reached the combined clinical outcome of nonelective hospitalization and/or death. FVC < 60% predicted was independently associated with the risk for the combined clinical outcome (RR 6.68 (95% CI 2.49-17.94), P < .001). CONCLUSIONS Abnormal pulmonary function characterized by reduced FVC is common in adults with repaired TOF. Patients with FVC < 60% predicted had a 6 times higher rate of hospitalization and/or death compared to those with FVC ≥ 60%.

CORONARY ARTERY DISEASE SCREENING IN ADULTS WITH CONGENITAL HEART DISEASE PRIOR TO CARDIAC SURGERY

As adults with congenital heart disease (CHD) grow older, pre-operative screening for coronary artery disease (CAD) may be indicated prior to CHD surgery. There is limited data on timing/methods for pre-operative CAD screening in CHD population. Current practice is to follow ACC/AHA guidelines for

Is isomerism a risk factor for intestinal volvulus

INTRODUCTION Isomerism, or heterotaxy syndrome, affects many organ systems anatomically and functionally. Intestinal malrotation is common in patients with isomerism. Despite a low reported risk of volvulus, some physicians perform routine screening and prophylactic Ladd procedures on asymptomatic patients with isomerism who are found to have intestinal malrotation. The primary aim of this study was to determine if isomerism is an independent risk factor for volvulus. METHODS Kids Inpatient Database data from 1997 to 2012 was utilized for this study. Characteristics of admissions with and without isomerism were compared with a particular focus on intestinal malrotation, volvulus, and Ladd procedure. A logistic regression was conducted to determine independent risk factors for volvulus with respect to isomerism. RESULTS 15,962,403 inpatient admissions were included in the analysis, of which 7970 (0.05%) patients had isomerism, and 6 patients (0.1%) developed volvulus. Isomerism was associated with a 52-fold increase in the odds of intestinal malrotation by univariate analysis. Of 251 with isomerism and intestinal malrotation, only 2.4% experienced volvulus. Logistic regression demonstrated that isomerism was not an independent risk factor for volvulus. CONCLUSION Isomerism is associated with an increased risk of intestinal malrotation but is not an independent risk factor for volvulus. TYPE OF STUDY Prognosis study. LEVEL OF EVIDENCE Level III.

The need for extracorporeal membrane oxygenation in adults undergoing congenital heart surgery: Impact and trends of utilization

Introduction: Adults with congenital heart disease (ACHD) represent a population with unique health-care needs. Many patients require cardiac surgery, with some requiring postoperative extracorporeal membrane oxygenation (ECMO). This study aimed to identify the risk factors for the need of postoperative ECMO and characterize the impact of ECMO on admission characteristics. Methods: Data from the 2005–2012 iterations of the Nationwide Inpatient Sample were used. ACHD admissions over 18 years with a documented cardiac surgery were included. Univariate analysis was conducted to compare the characteristics between those requiring ECMO and those who did not. Regression analysis was done to identify the independent risk factors associated with ECMO and to determine the impact of ECMO on length, cost, and mortality of the admission. Results: A total of 186,829 admissions were included. Of these, 446 (0.2%) admissions required ECMO. Those with acute kidney injury, double-outlet right ventricle, or total anomalous pulmonary venous connection were more likely to require ECMO. ECMO was also significantly more utilized in patients undergoing septal defect repair, complete repair of tetralogy of Fallot, atrial switch, and heart transplant. The use of ECMO significantly increased length, cost, and mortality of stay. Overall mortality was 62.6% in the ECMO group. Conclusion: ECMO is only needed in a small proportion of postoperative ACHD patients. The use of ECMO significantly increases cost, length of stay and mortality in these patients. Improved identification of postoperative ACHD patients who are more likely to survive ECMO may facilitate improved survival and decreased resource utilization.