The influence of seasons and lunar cycle on hospital outcomes following ascending aortic dissection repair.

OBJECTIVES: The effect of the lunar cycle and seasonal variation on ascending aortic dissection surgery outcomes is unknown. We investigated these temporal effects on risk-adjusted hospital mortality and then on the length of stay (LOS) following surgery for survivors. METHODS: We examined prospectively collected data from cardiac operations at two major centres within a single state between January 1996 and December 2011. We first examined the relationship between the lunar cycle and seasonal variation, along with demographic and risk profile covariates, with mortality using univariate analyses, followed by multiple logistic regression modelling that controlled for demographic and patient risk variables including age, gender, risk profile (diabetes, hypertension, dyslipidaemia and renal failure), and two surgical groups: Group A, consisting of patients having repair of ascending aorta dissection repair only, and Group B, with those having ascending aorta repair plus aortic valve surgery or coronary bypass surgery or both. We further examined the relationship with LOS using both univariate and multiple regression analyses. RESULTS: There were 210 patients who had repair of dissection in the study period, with 109 patients in Group A and 101 in Group B. The average age of this sample was 59.5 (standard deviation = 16.0), 65.7% were male and 18.1% died prior to discharge following repair. The greatest percentage of deaths occurred in winter (31.6%, n = 12), while the least were in summer (21.1%, n = 8) and fall (21.1%, n = 8). An overall χ(2) test found there was no difference in mortality for season (P = 0.55). Univariate analyses also found the age of patients who died vs lived was significantly higher (65.9 vs 58.1 years; P = 0.001), and a significantly greater (P = 0.029) percentage of patients with diabetes vs without diabetes died (41.7 vs 16.7%). Univariate analyses found all other covariates were not significantly related to mortality. In the multiple logistic regression model, there was no significant effect for season, while the odds of dying increased with age (odds ratio [OR] = 1.04, 95% confidence interval [95% CI] = 1.01-1.07, P = 0.012), and the odds of dying in the full-moon cycle vs the new moon cycle was significantly reduced (OR = 0.21, 95% CI = 0.05-0.81, P = 0.024). No other covariate significantly increased or decreased the odds of death, including diabetes risk, which had been significantly related to death in the univariate analysis. Within a linear regression model that examined the relationship with LOS, Group B (P = 0.020), male sex (P = 0.036) and the full-moon lunar phase (P = 0.001) were significantly related to shorter LOS. CONCLUSIONS: Season had no effect on mortality or LOS following aortic dissection repair, while patient age significantly increased the odds of death. The full-moon cycle appeared to reduce the odds of death, and the full-moon cycle, along with being male and requiring a concomitant cardiac procedure, was associated with shorter LOS.

Energy loss and coronary flow simulation following hybrid stage I palliation: a hypoplastic left heart computational fluid dynamic model.

OBJECTIVES: The theoretical differences in energy losses as well as coronary flow with different band sizes for branch pulmonary arteries (PA) in hypoplastic left heart syndrome (HLHS) remain unknown. Our objective was to develop a computational fluid dynamic model (CFD) to determine the energy losses and pulmonary-to-systemic flow rates. This study was done for three different PA band sizes. METHODS: Three-dimensional computer models of the hybrid procedure were constructed using the standard commercial CFD softwares Fluent and Gambit. The computer models were controlled for bilateral PA reduction to 25% (restrictive), 50% (intermediate) and 75% (loose) of the native branch pulmonary artery diameter. Velocity and pressure data were calculated throughout the heart geometry using the finite volume numerical method. Coronary flow was measured simultaneously with each model. Wall shear stress and the ratio of pulmonary-to-systemic volume flow rates were calculated. Computer simulations were compared at fixed points utilizing echocardiographic and catheter-based metric dimensions. RESULTS: Restricting the PA band to a 25% diameter demonstrated the greatest energy loss. The 25% banding model produced an energy loss of 16.76% systolic and 24.91% diastolic vs loose banding at 7.36% systolic and 17.90% diastolic. Also, restrictive PA bands had greater coronary flow compared with loose PA bands (50.2 vs 41.9 ml/min). Shear stress ranged from 3.75 Pascals with restrictive PA banding to 2.84 Pascals with loose banding. Intermediate PA banding at 50% diameter achieved a Qp/Qs (closest to 1) at 1.46 systolic and 0.66 diastolic compared with loose or restrictive banding without excess energy loss. CONCLUSIONS: CFD provides a unique platform to simulate pressure, shear stress as well as energy losses of the hybrid procedure. PA banding at 50% provided a balanced pulmonary and systemic circulation with adequate coronary flow but without extra energy losses incurred.

Left ventricle after palliation of hypoplastic left heart syndrome: friend, fiend, or innocent bystander?

Hypoplasia of the left side of the heart is the most common cause of death from congenital heart disease in the first weeks of life. Once considered a surgically fatal disease, hypoplasia has been successfully palliated for more than 30 years. Although the palliative route is staged by an early differential bypass of the systemic outflow and the venous inflow to the right ventricle, the left ventricle remains anatomically and biologically influential throughout. Given the variation of the left ventricle, contemporary outcomes for different hypoplastic left heart subsets can vary both early after palliation and long term. This review critically examines the contemporary understanding of the structure and function of the hypoplastic ventricle in this syndrome. It also provides insight into future research directions relevant to clinicians and surgeons.

Comparison of risk factors and outcomes for pediatric patients listed for heart transplantation after bidirectional Glenn and after Fontan: an analysis from the Pediatric Heart Transplant Study.

BACKGROUND: Patients listed for transplant after the bidirectional Glenn (BDG) may have better outcomes than patients listed after Fontan. This study examined and compared outcomes after listing for BDG and Fontan patients. METHODS: All patients listed for transplant after the BDG in the Pediatric Heart Transplant Study between January 1993 and December 2008 were evaluated. Comparisons were made with Fontan patients and with a matched cohort of congenital heart disease patients. Competing outcomes analysis and actuarial survival were evaluated for the study populations, including an examination of various risk factors. RESULTS: Competing outcomes analysis for BDG and Fontan patients after listing were similar. There was no difference in actuarial survival after listing or transplant among the 3 cohorts. Mechanical ventilation, United Network of Organ Sharing status, and age were risk factors for death after listing in BDG and Fontan patients, but ventilation at the time of transplant was significant only for the Fontan patients. Mortality was increased in Fontan patients listed < 6 months after surgery compared with patients listed > 6 months after surgery, but no difference was observed in BDG patients. There was a trend toward improved survival after listing for both populations across 3 eras of the study, but this did not reach statistical significance. CONCLUSION: Outcomes after listing for BDG and Fontan patients are similar. Mechanical ventilation at the time of transplant remains a significant risk factor for death in the Fontan population, as does listing for transplant soon after the Fontan, suggesting that some patients may benefit from transplant instead of Fontan completion.

Outcome after repair of atrioventricular septal defect with tetralogy of Fallot.

BACKGROUND: Long-term outcomes of repair of tetralogy of Fallot associated with complete atrioventricular septal defect are seldom reported. We report our survival and reintervention outcomes over a 29-year time period. METHODS: Between March 1979 and April 2008, 61 patients with the combined cardiac defect of atrioventricular septal defect and tetralogy of Fallot were surgically managed. Trisomy 21 was present in 49 (80%) patients. Primary repair was performed in 36 patients at a median age of 9 months (range, 1 month to 16 years), whereas 25 patients had initial palliation by systemic-pulmonary shunt at a median age of 21 months (range, 0 days to 36 years). Thirty-one (51%) patients had a transannular patch. Fifty-three patients required right ventriculotomy for relief of the right ventricular outflow tract obstruction. Four patients had a right ventricle-pulmonary artery conduit with a homograft. Relationships between patient characteristics and outcome variables were examined using Kaplan-Meier survival curves; comparisons were performed using the log-rank test. RESULTS: Median follow-up was 4.7 years. A total of 12 patients died during the course of follow-up: 4 (7%)deaths within 30 days of surgery and 8 late deaths (range, 4 months to 9.9 years after repair). Since 2000, there have been no early deaths and 1 late death, 5 months after the operation. The estimated survival at 5 years after definitive repair was 82% (95% confidence interval, 69%, 90%). Time to death was not associated with any patient or surgical variables examined. Overall, 30% of the survivors required a reoperation. The type of reoperations was on the mitral valve (4 repairs, 4 replacements) and 7 pulmonary valve replacements. We did not find an effect of era on mortality (P = .23 for comparison of 1979-1989, 1990-1999, and 2000-2008). The percentage of patients with primary repair did not change during the different quartiles. The estimated freedom from reoperation at 5 years was 80% (65%, 90%). Time to reoperation was shorter for patients with a conduit (P = .01). CONCLUSIONS: Excellent long-term survival was achieved after repair of tetralogy of Fallot associated with complete atrioventricular septal defect. Palliation and primary repair resulted in comparable outcomes; as such, primary repair is favored. The choice of right ventricular outflow tract reconstruction affects the need for reoperation.

The effect of transplant center volume on survival after heart transplantation: a multicenter study.

OBJECTIVE: Few studies have examined the association between procedural volume and clinical outcomes in heart transplantation. This retrospective study was performed on a contemporary cohort of heart transplant recipients to better elucidate the effect of transplant center volume on 1-year mortality. METHODS: Data from the Scientific Registry of Transplant Recipients were used to analyze the relationship between transplant center volume and short-term survival. Center volume designation (very low, low, medium, and high) was assigned on the basis of quartiles with approximately equal numbers of patients per group. Survival differences were explored using Cox proportional hazards modeling to adjust for differences in variables between volume groups and to determine variables associated with 1-year mortality. RESULTS: Between January 1, 1999, and May 31, 2005, 13,230 heart transplantations were performed at 147 transplant centers in the United States. Although most recipient and donor characteristics were similar across quartiles, larger volume centers were more likely to perform transplantations in older candidates and accept organs from older donors with longer cold ischemia times. A statistically significant relationship between transplant center volume and 1-year mortality was observed. Compared with the reference group (very low volume), the hazard ratios for the low, medium, and high-volume quartiles were 0.71, 0.64, and 0.56, respectively (P < .001 for each group compared with the reference). CONCLUSION: There was a significant association between transplant center volume and 1-year survival. Patients who undergo cardiac transplantation at very low-volume centers are at higher risk for early mortality than those who undergo transplantation in higher-volume centers.

The influence of preoperative use of ventricular assist devices on survival after heart transplantation: propensity score matched analysis.

OBJECTIVE: To determine the influence of the preoperative placement of a left ventricular assist device on survival after heart transplantation. DESIGN: Prospective cohort study. SETTING: Organ sharing database with patient level data on heart transplants in the United States. PARTICIPANTS: 2786 adults aged 18 or older in status 1A or 1B (highest priority for heart transplantation with either some form of ventricular assist device, intravenous inotrope, or life expectancy of less than seven days), based on the United Network for Organ Sharing Registry, 1996-2004. MAIN OUTCOME MEASURE: Survival after heart transplantation in patients who did and did not receive a left ventricular assist device. RESULTS: The left ventricular assist device was not associated with decreased survival, even after the data were stratified by propensity score (the odds of being a treated patient). Inspection of the strata showed no difference in survival between patients who received the device and those who did not. The hazard ratios in strata 1 to 5 were 0.69, 1.37, 1.55, 0.75, and 1.19, respectively, and none was statistically significant. CONCLUSION: Overall, survival after heart transplantation in patients who received a left ventricular assist device before transplantation was comparable to those who did not receive the device.

Current options and outcomes for the management of atrioventricular septal defect.

A wealth of experience has been gained in the management of atrioventricular septal defect (AVSD) since the first complete correction of this malformation in 1955. The success of surgical therapy followed an enhanced understanding of morphology and physiology as well as major improvements in imaging of this congenital heart defect. Therapeutic success in the management of patients with AVSD has been extended to include those with associated lesions such as tetralogy of Fallot, double outlet right ventricle and relative degrees of ventricular hypoplasia. Although operative mortality is low and long-term survival is relatively good, important detrimental residual or AVSD-related complications such as left atrioventricular valve regurgitation, left ventricular outflow tract obstruction still carry significant late morbidity in a proportion of patients. This article reviews our current understanding of the morphology of this defect, aspects of diagnosis and surgical treatment options.

Survival of primary and repeat lung transplantation in the United States.

BACKGROUND: This study was undertaken to compare survival between primary and repeat lung transplant recipients and to identify survival predictors after repeat lung transplantation. METHODS: Data for 10,846 primary and 354 repeat lung transplant patients were extracted from the United Network for Organ Sharing registry. Propensity score matching was used to examine balance in the distribution of potential observed confounders and to match the sample in terms of the probability of repeat lung transplantation given pretransplant characteristics alone. Matching based on the propensity score was used to compare survival between the primary and repeat lung transplant groups. A Cox regression model was used to identify risk factors for death in the cohort of patients receiving lung transplant. RESULTS: Considerable bias between the primary and repeat lung transplant groups was found in the sample. Patients with high propensity scores tended to carry high-risk profiles. Propensity score matching revealed incomplete overlap of covariate distributions between primary and repeat transplant groups. For those subjects who could be matched for the set of potential confounding variables, no difference in survival time was observed between primary and repeat lung transplant patients. Functional status and serum creatinine level were the two clinically important risk factors for predicting the survival of repeat transplant patients. CONCLUSIONS: The current study revealed that direct comparison of the survival of primary and repeat lung transplant patients is biased by nonoverlap in the distribution of potential confounders. Using propensity score matching we adjusted for this bias and found that there was no significant difference in survival between first and second transplants.

The influence of seasonal variation on cardiac surgery: a time-related clinical outcome predictor.

OBJECTIVE: The effect of seasonal variation on cardiac surgery outcomes is unknown. We investigated the effect of season on risk-adjusted hospital mortality and length of stay. METHODS: Prospectively collected data from cardiac operations at one center between April 1996 and March 2006 were analyzed. Seasonal variation in outcomes was studied by using multiple regression models that included EuroSCORE and year of operation to adjust for risk profile and changes over time. Analysis was performed for 2 separate surgical groups: patients having coronary artery bypass grafting only and patients having other cardiac procedures with or without coronary artery bypass grafting. RESULTS: There were 16,290 patients who had a first record of cardiac surgery in the study period between April 1, 1996, and March 31, 2006, with 10,263 patients having coronary artery bypass grafting only and 6027 patients having another procedure with or without coronary artery bypass grafting. There were increased odds of hospital mortality in patients having operations in winter compared with the average across all seasons for both surgical groups, although this was only significant in the coronary artery bypass grafting-only group (odds ratio, 1.29; 95% confidence interval, 1.01-1.63; P = .04). There were decreased odds of death in the coronary artery bypass grafting-only group in summer (odds ratio, 0.76; 95% confidence interval, 0.60-0.96; P = .02). Intensive care unit stay was 4% (95% confidence interval, 1%-6%) longer in the coronary artery bypass grafting-only group in winter and 3% (95% confidence interval, 1%-5%) shorter in summer than the average stay (P = .003 and .006, respectively). There were no differences in intensive care unit stay in the combined surgery group by season and no differences in total length of stay for either group (coronary artery bypass grafting only and coronary artery bypass grafting with other cardiac procedures). CONCLUSIONS: Cardiac surgery outcomes are influenced by the time of year. Hospital mortality and intensive care unit stay after coronary artery bypass grafting were increased during the winter season compared with the rest of the year.

Repeat heart-lung transplantation outcome in the United States.

OBJECTIVES: This study compared risk-adjusted survival between primary and repeat heart-lung transplantation. METHODS: Data for 799 primary heart-lung and 19 repeat heart-lung transplants were extracted from the United Network Organ Sharing (UNOS) registry. Analyses were based on propensity score matching in which 1, 2, and 3 primary transplant patients were matched with 19 repeat transplant patients. The matching variables were sex of recipient and donor, ethnicity, race, age of recipient and donor, cytomegalovirus status, ABO match, human leukocyte antigen mismatch, medical condition (hospitalized), ventilator, employment status, functional status, UNOS transplant status, and ischemic time. RESULTS: Propensity score matching revealed incomplete overlap of covariate distributions between primary and repeat transplant patients. The 19 repeat heart-lung transplant patients were more severely impaired at the time of transplant, and 4 did not have an adequate primary transplant match. For 15 repeat transplant patients, survival time was not significantly different from matched primary transplant controls. For repeat transplant patients, being Hispanic, having longer ischemic time, poor functional status (needing assistance), being hospitalized, and requiring ventilator support were all associated with decreased survival time; however, only being on a ventilator was statistically significant. By contrast, being female, and younger were associated with increased survival, but were not statistically significant. CONCLUSIONS: When matched for a set of potential confounding variables, no difference in survival benefit was observed between primary and repeat heart-lung transplant patients. The only predictor significantly associated with decreased survival time among repeat transplant patients was being on a ventilator.

Impact of cardiothoracic resident turnover on mortality after cardiac surgery: a dynamic human factor.

BACKGROUND: The study was designed to determine whether cardiac surgical outcomes are affected during times of major turnover of cardiothoracic resident surgical staff and at the beginning versus the end of their training periods. METHODS: This observational cohort study analyzed data from cardiac operations between April 1996 and March 2006 at a single institution. In-hospital mortality and other outcomes were compared between operations done during months of major change in resident staff rotation (July, August, January, February, n = 5,517) and the rest of the year (n = 10,773). We also compared outcomes at the beginning and end of surgical rotation for cardiothoracic residents. Adjustment was made for EuroSCORE (European System for Cardiac Operative Risk Evaluation), year of operation, and surgeon resident status. Analyses were done within surgery procedure subgroups of isolated coronary artery bypass graft surgery (CABG) and complex operations (CABG combined with other procedures). RESULTS: Patient populations in the groups were similar. After risk adjustment, there was a significant increase in hospital mortality for the complex cases during months of resident staff change compared with rest of the year (odds ratio 1.3, 95% confidence interval: 1.3, 1.4; p = 0.02). There was, however, no significant difference in mortality for the CABG only cases (odds ratio 1.1, 95% confidence interval: 0.8, 1.4; p = 0.61). Risk-adjusted mortality after operations done by residents was the same at the start and finish of their surgical rotation. During the change months, the surgery time was 2.2 minutes longer on average in CABG operations (95% confidence interval: 0.3, 4.0; p = 0.02), and no different in combined cases. CONCLUSIONS: Periods of major change in resident surgical staff are associated with increased risk-adjusted in-hospital mortality after complex cardiac operations but not after CABG alone.

Does perioperative use of aprotinin reduce the rejection rate in heart transplant recipients?

OBJECTIVE: Allograft rejection continues to be one of the most common causes of mortality after heart transplantation. We investigated if perioperative use of antifibrinolytics such as aprotinin and tranexamic acid can decrease the rate of rejection after heart transplant and their effect on transfusion. METHODS: A retrospective analysis was conducted on the data from patients who received a first heart transplant at Papworth Hospital between 2000 and 2005. Transplant registry and audit data were used for the study. Rejection biopsy results and treatment were used to designate rejection episodes as mild (grades 1A, 1B or 2 untreated) or severe (grades 2 treated, grades 3 and 4). The relationship between antifibrinolytics and rejection episodes was assessed using univariate and multiple Poisson regression. Kaplan-Meier methods and Kruskal-Wallis tests, respectively, were used to analyse survival/time to first rejection and transfusion. RESULTS: There were 225 patients who underwent a first heart transplant between January 2000 and December 2005. Of these, 101 patients (44.9%) had received aprotinin, 63 (28.0%) tranexamic acid, 2 (0.9%) both (aprotinin and tranexamic acid) and 59 (26.2%) no antifibrinolytics. There was no difference in time to first rejection by antifibrinolytic treatment (p=0.20). There was no difference in the rate of treated rejection per 100 patient-days between aprotinin and tranexamic acid groups between 0 and 3 months post-transplant, (0.6 in both), but aprotinin had a small clinical effect when compared to no treatment (0.6 vs 0.8, p=0.54). Between 4 and 6 months, the treated and severe rejection rates were lower in the patients receiving aprotinin as compared to those receiving tranexamic acid, but these differences again did not reach statistical significance (0.1 vs 0.3, p=0.14, 0.2 vs 0.4, p=0.18). Aprotinin was associated with higher postoperative blood loss and transfusion requirements in the subgroup of patients that had a ventricular assist device, prior sternotomy or anticoagulant therapy. CONCLUSIONS: The use of aprotinin in heart transplant surgery may be associated with a small decrease in the incidence of treated/severe rejection within 6 months of transplantation. The perioperative use of antifibrinolytics did not influence time to first rejection or reduce blood transfusion.

The Papworth experience with the Levitronix CentriMag ventricular assist device.

OBJECTIVES: The Levitronix CentriMag ventricular assist device (VAD) is a centrifugal pump designed for short-term extracorporeal support in cardiogenic shock. The aim of this study is to report our clinical experience with the Levitronix CentriMag for uni- and biventricular support. METHODS: Between July 2004 and December 2006, 27 patients were supported using the Levitronix CentriMag device. Nineteen were male. Mean age was 47.9 (range 19 to 72) years. Indications for support at implantation were cardiogenic shock that included: end-stage heart failure and too ill to undergo transplantation, with questionable neurologic status (9 subjects); right ventricular failure after left VAD (LVAD) implantation (5 subjects); post-cardiotomy status (7 subjects); and acute donor graft failure after heart transplantation (6 subjects). RESULTS: Post-VAD 30-day survival was 30% (8 patients). Mean support time was 11 days for all patients (range 1 to 51 days). Mean support time for 14 Levitronix biventricular VADs was 11 (range 1 to 51) days. Mean support time for 7 Levitronix LVADs was 13.7 (range 1 to 30) days. The highest survival rates after Levitronix support were after donor graft failure (50%) and after cardiotomy (42%). Levitronix right VAD (RVAD) support after long-term LVAD insertion incurred 100% hospital mortality. Of those who survived, 8 patients were discharged home after VAD support and remain alive to date. Two patients were bridged to primary and another bridged to repeat heart transplantation. Five patients were weaned to recovery. Re-operation for bleeding occurred in 8 patients, clinical evidence of cerebral thromboembolism in 3, overwhelming sepsis in 1, and aortic thrombus formation in 1. Clot formation in the tubing was observed in 1 patient, necessitating emergent replacement at bedside, which was successful. CONCLUSIONS: The Levitronix CentriMag system is a reliable and facile temporary circulatory support system as a bridge to decision in patients with refractory acute cardiogenic shock.