Michael Salna

Acute kidney injury after aortic valve replacement: incidence, risk factors and outcomes

The occurrence of acute kidney injury (AKI) following aortic valve replacement (AVR) has very serious clinical implications and has therefore been the focus of several studies. The authors report the results of previous studies evaluating both transcatheter AVR (TAVR) and indirectly surgical AVR (SAVR) through looking at cardiopulmonary bypass (CPB) cardiac surgeries, and identify the incidence, predictors and outcomes of AKI following AVR. In most studies, AKI was defined using the Risk, Injury, Failure, Loss and End Stage, Valve Academic Research Consortium (modified Risk, Injury, Failure, Loss and End Stage) or Valve Academic Research Consortium-2 (Acute Kidney Injury Network) AKI classification criteria. Twelve studies including more than 90,000 patients undergoing cardiac surgery on CPB were considered as well as 26 studies with more than 6000 patients undergoing TAVR. Depending on the definition used, AKI occurred in 3.4–43% of SAVR cases with up to 2.5% requiring dialysis, and in 3.4–57% of TAVR cases. Factors identified as independent predictors of AKI were: baseline kidney failure, EUROSCORE, diabetes mellitus, hypertension, chronic obstructive pulmonary disease, anemia, peripheral vascular disease, heart failure, surgical priority, CPB time, reoperation, use of intra-aortic balloon pump, need for re-exploration, contrast agent volume, transapical access, blood transfusion, postoperative thrombocytopenia, postoperative leukocytosis as well as demographic variables such as age and female gender. The 30-day mortality rate for patients with AKI following SAVR ranged from 5.5 to 46% and was 3- to 16-times higher than in those without AKI. Similarly, patients who developed AKI after TAVR had a mortality rate of 7.8–29%, which was two- to eight-times higher than those who did not suffer from AKI. AKI confers up to a fourfold increase in 1-year mortality. Finally, hospital length of stay was significantly increased in patients with AKI in both SAVR and TAVR groups, with increases up to 3- and 2.5–times, respectively.

Sustained Increased Entry of Medical Students into Surgical Careers: A Student-Led Approach

OBJECTIVE To determine whether a surgical interest group run entirely by preclinical students can influence medical students to enter general surgery residency programs. DESIGN Matriculation rates into general surgery and affiliated subspecialties from Columbia University College of Physicians and Surgeons residency match lists were compared to National Residency Match Program data for all U.S. senior students from 2006 to 2014. SETTING The Columbia University College of Physicians and Surgeons. RESULTS After establishing the interest group, entrance rates into general surgery programs tripled from the early 2000s to more than 12% of 2006 Columbia University College of Physicians and Surgeons graduates. After 8 years, our data illustrate sustained results, with more than 8% of students entering surgical residencies, significantly higher than the National Residency Match Programs average (p < 0.025). CONCLUSIONS Surgical interest groups spark early and lasting interest in surgery that may influence residency decisions. Moreover, these programs can be successfully run entirely by preclinical students and implemented in other institutions.

Extracorporeal lung support.

Purpose of review The applications for extracorporeal membrane oxygenation for lung support are constantly evolving. This review highlights fundamental concepts in extracorporeal lung support and describes directions for future research. Recent findings Since the 1950s, extracorporeal lung support has experienced continuous advancements in circuit design and safety in acute respiratory distress syndrome, chronic obstructive pulmonary disease exacerbations, as a bridge to transplantation, intraoperative cardiopulmonary support, and for transportation to referral centers. Patients on extracorporeal membrane oxygenation are now capable of being awake, extubated, and ambulatory for accelerated recovery or optimization for transplantation. Summary Extracorporeal lung support is a safe and an easily implemented intervention for refractory respiratory failure. Recent advances have extended its use beyond acute illnesses and the developments for chronic support will facilitate the development of durable devices and possible artificial lung development.

Outcomes of the Arterial Switch Operation in ≤2.5-kg Neonates

Although low birth weight is a known risk factor for mortality in congenital heart lesions and may consequently delay surgical repair, outcomes in low-weight neonates undergoing the arterial switch operation (ASO) have not been well described. Our objective was to assess the safety of this procedure in infants weighing ≤2.5 kg at the time of surgery. We retrospectively analyzed outcomes for all neonates undergoing the ASO at our institution from 2005 to 2015. Our primary outcome of interest was major morbidity or operative mortality, assessed as a composite outcome. From 2005 to 2015, 217 neonates underwent the ASO, with 31 (14%) weighing ≤2.5 kg at the date of surgery, and 8 weighing <2.0 kg. Neonates weighing ≤2.5 kg were more likely to be premature than those weighing >2.5 kg, but there was no difference in the age at operation between these groups. Overall, 32 infants experienced a major morbidity or mortality, including 37.5% (n = 3) weighing <2.0 kg, 8.7% (n = 2) weighing 2.0-2.5 kg, and 14.5% (n = 7) weighing >2.5 kg (P = 0.141). One infant weighing <2.0 kg (1.1 kg) and 4 infants weighing >2.5 kg died. In multivariable models, odds of major morbidity or mortality were significantly higher for infants weighing <2 kg compared with infants weighing >2.5 kg (odds ratio 3.93, 95% confidence interval 1.04-14.85, P = 0.044), but there was no difference between infants weighing 2.0-2.5 kg and those weighing >2.5 kg (P = 0.225). The ASO can be performed safely in 2.0- to 2.5-kg neonates and yields results comparable with higher weight infants. Imposed delays for corrective surgery may not be necessary for these low-weight infants with transposition of the great arteries.

Morbid obesity is not a contraindication to transport on extracorporeal support

OBJECTIVES Extracorporeal membrane oxygenation (ECMO) transport has not been described in morbidly obese patients, a population that can pose significant challenges in obtaining vascular access, indexed flows and transport logistics. We sought to study the feasibility and safety of transporting obese and morbidly obese patients during extracorporeal support. METHODS We conducted a retrospective review of all patients transported to our institution while receiving ECMO from September 2008 to September 2016. Survival to decannulation and survival to discharge were the primary outcomes. Obesity and morbid obesity were defined as a body mass index of greater than 30 kg/m2 and greater than 40 kg/m2, respectively. RESULTS From 2008 to 2016, 222 patients were transported to our institution while receiving ECMO. Among these included patients, 131 were non-obese (interquartile range 22-27 kg/m2), 63 were obese (interquartile range 31-35 kg/m2) and 28 were morbidly obese (interquartile range 41-49 kg/m2), with 6 patients having a body mass index greater than 50 kg/m2 (range 52.3-79 kg/m2). Pre-ECMO arterial blood gases, disease severity indices, cannulation strategies and transport distances were similar between these 3 groups. There was no mortality of patients during transport, and survival to discharge was 66% (n = 87) in non-obese patients, 56% (n = 35) in obese patients and 82% (n = 23) in morbidly obese patients (P = 0.042). On multivariable logistic regression analysis, body mass index was not a predictor of in-hospital mortality (odds ratio 0.99, 95% confidence interval 0.95-1.03; P = 0.517). CONCLUSIONS Transport of morbidly obese patients receiving ECMO may be performed safely and with excellent results in the setting of a dedicated ECMO transport programme with well-established management protocols.