Duc Nguyen

Gender differences in the risk of stroke during support with continuous-flow left ventricular assist device

BACKGROUND There is increasing recognition that the risk of stroke after left ventricular assist device (LVAD) implantation varies based on gender, with a higher risk in female patients. We reviewed our own data to determine gender differences in the risk of stroke. METHODS Frequency of stroke, including intracranial hemorrhage and ischemic stroke, was retrospectively evaluated in 110 heart failure patients (mean age 49.6 ± 13.6 years, 32% women) discharged from the hospital after implantation of a HeartMate II (N = 74) or HeartWare (N = 36) LVAD. Competing outcomes analysis was used to determine which clinical risk factors were associated with the risk of stroke and death, with the primary end-point being time to first stroke event. RESULTS During a median follow-up of 1.3 years, 26 patients had a stroke (23.6%, 0.14 case per person-year). The median time to first stroke was 0.7 (interquartile range 0.3 to 1.4) years. After adjusting for covariates, risk of stroke was higher for women than for men (hazard ratio 3.1, 95% confidence interval 1.4 to 6.9; p = 0.007). There was no difference in overall survival between men and women. CONCLUSION The risk of stroke after LVAD varies based on gender, with a higher risk in female patients. More research is needed to fully understand these differences, and whether device management strategies should be tailored based on gender.

Multidrug-Resistant Organism Infections in Patients with Left Ventricular Assist Devices

Left ventricular assist devices improve survival prospects in patients with end-stage heart failure; however, infection complicates up to 59% of implantation cases. How many of these infections are caused by multidrug-resistant organisms is unknown. We sought to identify the incidence, risk factors, and outcomes of multidrug-resistant organism infection in patients who have left ventricular assist devices. We retrospectively evaluated the incidence of multidrug-resistant organisms and the independent risk factors associated with them in 57 patients who had permanent left ventricular assist devices implanted at our institution from May 2007 through October 2011. Outcomes included death, transplantation, device explantation, number of subsequent hospital admissions, and number of subsequent admissions related to infection. Infections were categorized in accordance with criteria from the Infectious Diseases Council of the International Society for Heart and Lung Transplantation. Multidrug-resistant organism infections developed in 18 of 57 patients (31.6%)-a high incidence. We found 3 independent risk factors: therapeutic goal (destination therapy vs bridging), P=0.01; body mass index, P=0.04; and exposed velour at driveline exit sites, P=0.004. We found no significant differences in mortality, transplantation, or device explantation rates; however, there was a statistically significant increase in postimplantation hospital admissions in patients with multidrug-resistant organism infection. To our knowledge, this is the first report in the medical literature concerning multidrug-resistant organism infection in patients who have permanent left ventricular assist devices.

Rapid Development and Implementation of an ECMO Program

Extracorporeal membrane oxygenation (ECMO) is an established therapy in the management of patients with refractory cardiogenic shock or acute respiratory failure. In this report, we describe the rapid development and implementation of an organized ECMO program at a facility that previously provided ad hoc support. The program provides care for patients within the Emory Healthcare system and throughout the Southeastern United States. From September 2014 to February 2015, 16 patients were treated with either venovenous or venoarterial ECMO with a survival to decannulation of 53.3% and survival to intensive care unit discharge of 40%. Of the 16 patients, 10 were transfers from outside facilities of which 2 were remotely cannulated and initiated on ECMO support by our ECMO transport team. Complications included intracerebral hemorrhage, bleeding from other sites, and limb ischemia. The results suggest that a rapidly developed ECMO program can provide safe transport services and provide outcomes similar to those in the existing literature. Key components appear to be an institutional commitment, a physician champion, multidisciplinary leadership, and organized training. Further study is required to determine whether outcomes will continue to improve.

De novo DQ donor‐specific antibodies are associated with worse outcomes compared to non‐DQ dnDSA following heart transplantation

Antibody‐mediated rejection (AMR) resulting from de novo donor‐specific antibodies (dnDSA) leads to adverse outcomes following heart transplantation (HTx). It remains unclear what role dnDSA to specific HLA antigens play in adverse outcomes. This study compares outcomes in patients developing dnDSA to DQ antigens with those developing non‐DQ dnDSA and those free from dnDSA.

Racial differences in the development of de-novo donor-specific antibodies and treated antibody-mediated rejection after heart transplantation

BACKGROUND Despite improvements in outcomes after heart transplantation, black recipients have worse survival compared with non-black recipients. The source of such disparate outcomes remains largely unknown. We hypothesize that a propensity to generate de-novo donor-specific antibodies (dnDSA) and subsequent antibody-mediated rejection (AMR) may account for racial differences in sub-optimal outcomes after heart transplant. In this study we aimed to determine the role of dnDSA and AMR in racial disparities in post-transplant outcomes. METHODS This study was a single-center, retrospective analysis of 137 heart transplant recipients (81% male, 48% black) discharged from Emory University Hospital. Patients were classified as black vs non-black for the purpose of our analysis. Kaplan-Meier and Cox regression analyses were used to evaluate the association between race and selected outcomes. The primary outcome was the development of dnDSA. Secondary outcomes included treated AMR and a composite of all-cause graft dysfunction or death. RESULTS After 3.7 years of follow-up, 39 (28.5%) patients developed dnDSA and 19 (13.8%) were treated for AMR. In multivariable models, black race was associated with a higher risk of developing dnDSA (hazard ratio [HR] 3.65, 95% confidence interval [CI] 1.54 to 8.65, p = 0.003) and a higher risk of treated AMR (HR 4.86, 95% CI 1.26 to 18.72, p = 0.021) compared with non-black race. Black race was also associated with a higher risk of all-cause graft dysfunction or death in univariate analyses (HR 2.10, 95% CI 1.02 to 4.30, p = 0.044). However, in a multivariable model incorporating dnDSA, black race was no longer a significant risk factor. Only dnDSA development was significantly associated with all-cause graft dysfunction or death (HR 4.85, 95% CI 1.89 to 12.44, p = 0.001). CONCLUSION Black transplant recipients are at higher risk for the development of dnDSA and treated AMR, which may account for racial disparities in outcomes after heart transplantation.

Moderate-to-Large Increases in Perioperative Serum Sodium Concentration Associated With Adverse Neurologic Events After Continuous Flow Left Ventricular Assist Device Implantation

OBJECTIVE It was hypothesized that preoperative hyponatremia is associated with increased 30-day mortality after left ventricular assist device placement, and that large increases in sodium concentration are associated with adverse neurologic events and 30-day mortality. DESIGN Data were collected retrospectively on all patients having continuous flow left ventricular assist device implantation between January 1, 2009 and March 31, 2013. Preoperative variables, operative variables, and perioperative sodium concentrations were recorded. Both 30-day mortality and 72-hour adverse neurologic events (stroke or seizure) were recorded as primary outcome variables. Preoperative sodium and Δ sodium (postoperative sodium-preoperative sodium) were analyzed as tests for 30-day mortality and adverse neurologic events using receiver operating characteristic curves. Both crude and adjusted logistic regression analyses were used to estimate odds ratios for the outcome variables. SETTING Tertiary care academic medical center. PARTICIPANTS Patients having durable continuous flow left ventricular assist device placement. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Among 88 patients, 30-day mortality was 14% (12 of 88) and the rate of perioperative stroke or seizure was 9% (8 of 88). There were 3 strokes and 5 tonic-clonic seizures. Preoperative sodium was a poor discriminative test for 30-day mortality and stroke or seizure (AUC=0.47 and 0.57, respectively). Δ sodium was a poor discriminative test for 30-day mortality, but a fair discriminative test for stroke or seizure (AUC=0.55 and 0.78, respectively). Δ sodium was a good discriminative test for seizure alone (AUC=0.82) and a fair discriminative test for stroke alone (AUC=0.70). It also increased the odds of stroke or seizure significantly, even when adjusting for possible confounders. CONCLUSIONS Moderate-to-large increases in sodium concentration during left ventricular assist device placement appear to be associated with adverse postoperative neurologic events. Preoperative hyponatremia has no relationship with 30-day mortality or adverse perioperative neurologic events.