Mixed effect of increasing outflow of medical patients from an emergency department

Background and aim

Since 2014, the annual number of patients entering our emergency department (ED) has increased significantly. These were primarily Internal Medicine (IM) patients, and of these, 25–30% were admitted. The present governmental policy presents a deterrent to adding IM beds for these patients, and Emergency and IM departments cope with ever-increasing number of IM patients. We describe a quality improvement intervention to increase outflow of IM patients from the ED to the IM departments.

Methods

We conducted a quality improvement intervention at the Shaare Zedek Medical Center from 2014 to 2018. The first stage consisted of an effort to increase morning discharges from the IM departments. The second stage consisted of establishing a process to increase the number of admissions to the IM departments from the ED.

Results

Implementation of the first stage led to an increased morning discharge rate from a baseline of 2–4 to 18%. The second stage led to an immediate mean (± SD) morning transfer of 35 ± 7 patients to the medical departments (8–12 per department), providing significant relief for the ED. However, the additional workload for the IM departments’ medical and nursing staff led to a rapid decrease in morning discharges, returning to pre-intervention rates. Throughout the period of the new throughput intervention, morning admissions increased from 30 to > 70%, and were sustained. The number of patients in each department increased from 36 to 38 to a new steady state of 42–44, included constant hallway housing, and often midday peaks of 48–50 patients. Mean length of stay did not change. IM physician and nurse dissatisfaction led to increased number of patients being admitted during the evening and night hours and fewer during the morning.

Conclusion

We describe a quality improvement intervention to improve outflow of medical patients from the ED in the morning hours. The new ED practices had mixed effects. They led to less ED crowding in the morning hours but increased dissatisfaction among the IM department medical and nursing staff due to an increased number of admissions in a limited number of hours. The present governmental reimbursement policy needs to address hospital overcrowding as it relates to limited community healthcare beds and an aging population.

The need for cardiac surgery differential tariffs in Israel at the era of aging population and emerging technology: Importance of procedure type and patient complexity as assessed by EuroSCORE

Background

Reimbursement for cardiac surgical procedures in Israel is uniform and does not account for diversity in costs of various procedures or for diversity in patient mix. In an era of new and costly technology coupled with higher risk patients needing more complex surgery, these tariffs may not adequately reflect the true financial burden on the caregivers. In the present study we attempt to determine whether case mix and complexity of procedures significantly affect cost to justify differential tariffs.

Methods

We included all patients undergoing cardiac surgery at Shaare Zedek Medical Center between the years 1993–2016. Patients were stratified according to (1) type of surgery and (2) clinical profile as reflected by the predicted operative risk according to the European System for Cardiac Operative Risk Evaluation (EuroSCORE). Approximate cost of each group of patients was estimated by the average number of days in the Intensive Care Unit and days in the postoperative ward multiplied by the respective daily costs as determined by the Ministry of Health. We then added the fixed cost of the components used in the operating room (manpower and disposables). The final estimated cost (the outcome variable) was then evaluated as it relates to type of surgery and clinical profile. ANOVA was used to analyze cost variability between groups, and backward regression analysis to determine the respective effect of the abovementioned variables on cost. Because of non-normal distribution, both costs and lengths of stay were Log-transformed.

Results

Altogether there were 5496 patients: 3863, 836, 685 and 112 in the isolated CABG, CABG + valve, 1 valve and 2 valves replacement groups. By ANOVA, the costs in all EuroSCORE subgroups were significantly different from each other, increasing with increased EuroSCORE subgroup. Cost was also significantly different among procedure groups, increasing from simple CABG to single valve surgery to CABG + valve surgery to 2-valve surgery. In backward stepwise multiple regression analysis, both type of procedure and EuroSCORE group significantly impacted cost. ICU stay and Ward stay were significantly but weakly related while EuroSCORE subgroup was highly predictive of both ICU stay and ward stay.

Conclusions

The cost of performing heart surgery today is directly influenced by both patient profile as well as type of surgery, both of which can be quantified. Modern day technology is costly yet has become mandatory. Thus reimbursement for heart surgery should be based on differential criteria, namely clinical risk profile as well as type of surgery. Our results suggest an urgent need for design and implementation of a differential tariff model in the Israeli reimbursement system. We suggest that a model using a fixed, average price according to the type of procedure costs, in addition to a variable hospitalization cost (ICU + ward) determined by the patient EuroSCORE or EuroSCORE subgroup should enable an equitable reimbursement to hospitals, based on their case mix.

Implementing the Sphere Project's standards for patient's healthcare rights in the disaster zone: The experience of the Israeli field hospital in post-quake Nepal

Emergency medical teams (EMTs) encounter chaos upon arriving at the scene of a disaster. Rescue efforts are utilitarian and focus on providing the technical aspects of medical care in order to save the most lives at the expense of the individual. This often neglects the basic healthcare rights of the patient. The Sphere Project was initiated to develop universal humanitarian standards for disaster response. The increase in the number of EMTs led the World Health Organization (WHO) to organize standards for disaster response. In 2016, the WHO certified the Israel Defense Forces Field Hospital (IDF-FH) as the first to be awarded the highest level of accreditation (EMT-3). This paper presents the IDF-FH's efforts to protect the patient's healthcare rights in a disaster zone based on the Sphere Principles. These core Sphere Principles include the right to professional medical treatment; the right to dignity, privacy, and confidentiality; the right for information in an understandable language; the right to informed consent; the obligation to maintain private medical records; the obligation to adhere to universal ethical standards, to respect culture and custom and to care for vulnerable populations; the right to protection from sexual exploitation and violence; and the right to continued treatment.

Internet-delivered computerized cognitive & affective remediation training for the treatment of acute and chronic posttraumatic stress disorder: Two randomized clinical trials

Treatment of posttraumatic stress disorder (PTSD) is time and cost-intensive. New, readily implementable interventions are needed. Two parallel randomized clinical trials tested if cognitive/affective computerized training improves cognitive/affective functions and PTSD symptoms in acute (N = 80) and chronic PTSD (N = 84). Adults age 18-65 were recruited from an Israeli hospital emergency room (acute) or from across the United States (chronic). Individuals were randomized to an active intervention (acute N = 50, chronic N = 48) that adaptively trains cognition and an affective positivity bias, or a control intervention (acute N = 30, chronic N = 36) of engaging computer games. Participants, blind to assignment, completed exercises at home for 30 min/day over 30 days (acute) or 45 min/day over 45 days (chronic). Primary outcomes were computerized cognitive/affective function metrics. Secondary outcomes were Clinician-Administered PTSD Scale (CAPS) total scores. In chronic PTSD, the active arm demonstrated facilitated speed of fearful face identification (F = 20.96, q < 0.001; d = 1.21) and a trend towards improvement in total PTSD symptoms (F = 2.91, p = 0.09, d = 0.47), which was due to improvement in re-experiencing symptoms (F = 6.14, p = 0.015; d = 0.73). Better cognitive performance at baseline moderated the training effect and was associated with more favorable improvements on both metrics. Cognitive and affective training does not have widespread benefit on symptoms and cognitive/affective functions in PTSD. Future studies targeting re-experiencing a priori, stratifying on cognitive capacity, and with modified methods to infer on mechanisms and optimized training parameters may be warranted. ClinicalTrials.gov Identifiers: NCT01694316 &NCT02085512.

Deployment of field hospitals to disaster regions: Insights from ten medical relief operations spanning three decades

OBJECTIVE

The Israeli Defense Force (IDF) Medical Corps developed a model of airborne field hospital. This model was structured to deal with disaster settings, requiring self-sufficiency, innovation and flexible operative mode in the setup of large margins of uncertainty regarding the disaster environment. The current study is aimed to critically analyze the experience, gathered in ten such missions worldwide.

METHODS

Interviews with physicians who actively participated in the missions from 1988 until 2015 as chief medical officers combined with literature review of principal medical and auxiliary publications in order to assess and integrate information about the assembly of these missions.

RESULTS

A body of knowledge was accumulated over the years by the IDF Medical Corps from deploying numerous relief missions to both natural (earthquake, typhoon, and tsunami), and man-made disasters, occurring in nine countries (Armenia, Rwanda, Kosovo, Turkey, India, Haiti, Japan, Philippines, and Nepal). This study shows an evolutionary pattern with improvements implemented from one mission to the other, with special adaptations (creativity and improvisation) to accommodate logistics barriers.

CONCLUSION

The principals and operative function for deploying medical relief system, proposed over 20 years ago, were challenged and validated in the subsequent missions of IDF outlined in the current study. These principals, with the advantage of the military infrastructure and the expertise of drafted civilian medical professionals enable the rapid assembly and allocation of highly competent medical facilities in disaster settings. This structure model is to large extent self-sufficient with a substantial operative flexibility that permits early deployment upon request while the disaster assessment and definition of needs are preliminary.

Cognitive Flexibility Predicts PTSD Symptoms: Observational and Interventional Studies

Introduction: Post-Traumatic Stress Disorder (PTSD) is a prevalent, severe and tenacious psychopathological consequence of traumatic events. Neurobehavioral mechanisms underlying PTSD pathogenesis have been identified, and may serve as risk-resilience factors during the early aftermath of trauma exposure. Longitudinally documenting the neurobehavioral dimensions of early responses to trauma may help characterize survivors at risk and inform mechanism-based interventions. We present two independent longitudinal studies that repeatedly probed clinical symptoms and neurocognitive domains in recent trauma survivors. We hypothesized that better neurocognitive functioning shortly after trauma will be associated with less severe PTSD symptoms a year later, and that an early neurocognitive intervention will improve cognitive functioning and reduce PTSD symptoms. Methods: Participants in both studies were adult survivors of traumatic events admitted to two general hospitals' emergency departments (EDs) in Israel. The studies used identical clinical and neurocognitive tools, which included assessment of PTSD symptoms and diagnosis, and a battery of neurocognitive tests. The first study evaluated 181 trauma-exposed individuals one-, six-, and 14 months following trauma exposure. The second study evaluated 97 trauma survivors 1 month after trauma exposure, randomly allocated to 30 days of web-based neurocognitive intervention (n = 50) or control tasks (n = 47), and re-evaluated all subjects three- and 6 months after trauma exposure. Results: In the first study, individuals with better cognitive flexibility at 1 month post-trauma showed significantly less severe PTSD symptoms after 13 months (p = 0.002). In the second study, the neurocognitive training group showed more improvement in cognitive flexibility post-intervention (p = 0.019), and lower PTSD symptoms 6 months post-trauma (p = 0.017), compared with controls. Intervention- induced improvement in cognitive flexibility positively correlated with clinical improvement (p = 0.002). Discussion: Cognitive flexibility, shortly after trauma exposure, emerged as a significant predictor of PTSD symptom severity. It was also ameliorated by a neurocognitive intervention and associated with a better treatment outcome. These findings support further research into the implementation of mechanism-driven neurocognitive preventive interventions for PTSD.

Evaluating web-based cognitive-affective remediation in recent trauma survivors: study rationale and protocol

Background: The immediate aftermath of traumatic events is a period of enhanced neural plasticity, following which some survivors remain with post-traumatic stress disorder (PTSD) whereas others recover. Evidence points to impairments in emotional reactivity, emotion regulation, and broader executive functions as critically contributing to PTSD. Emerging evidence further suggests that the neural mechanisms underlying these functions remain plastic in adulthood and that targeted retraining of these systems may enhance their efficiency and could reduce the likelihood of developing PTSD. Administering targeted neurocognitive training shortly after trauma exposure is a daunting challenge. This work describes a study design addressing that challenge. The study evaluated the direct effects of cognitive remediation training on neurocognitive mechanisms that hypothetically underlay PTSD, and the indirect effect of this intervention on emerging PTSD symptoms. Method: We describe a study rationale, design, and methodological choices involving: (a) participants' enrolment; (b) implementation and management of a daily self-administered, web-based intervention; (c) reliable, timely screening and assessment of treatment of eligible survivors; and (d) defining control conditions and outcome measures. We outline the rationale of choices made regarding study sample, timing of intervention, measurements, monitoring participants' adherence, and ways to harmonize and retain interviewers' fidelity and mitigate eventual burnout by repeated contacts with recently traumatized survivors. Conclusion: Early web-based interventions targeting causative mechanisms of PTSD can be informed by the model presented in this paper.

Neutrophil-Lymphocyte Ratio: Prognostic Impact in Heart Surgery. Early Outcomes and Late Survival

BACKGROUND

The neutrophil-lymphocyte ratio (NLR) is a recognized marker of inflammation associated with poor outcomes in various clinical situations. We analyzed the prognostic significance of preoperative elevated NLR in patients undergoing cardiac surgery.

METHODS

We performed a retrospective review of 3,027 consecutive patients undergoing cardiac surgery. Receiver-operating-characteristic was used to determine the cutoff value for elevated NLR. Multivariate regression was used to determine the predictive value of preoperative NLR on clinical outcomes. Cox proportional hazards functions were used to determine predictors of late events. Late survival data to 16 years was obtained from the Ministry of Interior.

RESULTS

The cutoff value for elevated NLR was 2.6. Patients with elevated NLR were older (p < 0.0001), had a higher incidence of cardiac comorbidity (p < 0.0001), and higher European System for Cardiac Operative Risk Evaluation score (p < 0.0001). An elevated NLR emerged as an independent predictor of operative mortality (hazard ratio [HR] 2.15, 95% confidence interval [CI]: 1.51 to 3.08, p < 0.0001); pleural effusion (HR 1.42, 95% CI: 1.13 to 1.80, p = 0.003); low output syndrome (HR 1.54, 95% CI: 1.23 to 1.93, p = 0.0002); prolonged ventilation (HR 1.49, 95% CI: 1.23 to 1.82, p = 0.0001); or composite outcomes (HR 1.61, 95% CI: 1.36 to 1.91, p < 0.0001). The NLR emerged as an independent predictor of late mortality (HR 1.19, 95% CI: 1.11 to 1.28; p < 0.0001).

CONCLUSIONS

Elevated NLR is associated with a higher incidence of adverse outcomes after cardiac surgery. It is a predictor of operative as well as late mortality. Further studies are warranted to determine whether prophylactic treatment with antiinflammatory agents can prevent such outcomes. It may be warranted to include the baseline NLR as another variable in risk stratification of patients about to undergo cardiac surgery.

Morbidity among the Israeli Defense Force response team during Nepal, post-earthquake mission, 2015

BACKGROUND

On 25 April 2015, a 7.8-magnitude earthquake struck Nepal. Soon after, the Israel Defense Force (IDF) dispatched a rapid-response team and opened a tertiary field hospital in Kathmandu. There is limited data regarding the spectrum of diseases among rescue teams to disease-stricken areas. The aim of this study was to assess the morbidity among the field-hospital staff during the mission.

METHODS

The rescue team was deployed for a 2-week mission in Kathmandu. Pre-travel vaccinations were given prior to departure. The field-hospital was self-equipped including food and drinking water supply with a self-serving kitchen, yet had a shortage of running water. A Public Healthcare and Infectious-Diseases team was present and active during the entire mission. A survey assessing the morbidities and risk-factors throughout the mission was performed at the last day.

RESULTS

One hundred thirty-seven (69%) team members completed the questionnaire. Medical complaints were recorded in 87 of them (64%). The most common symptoms were gastrointestinal (GI) (53% of all responders, 84% of the 87 with symptoms). Respiratory symptoms were recorded in 16% and fever in only 8%. There was no significant difference in the rate or spectrum of morbidity between the medical and the non-medical staff.

CONCLUSIONS

The Israeli field hospital was a stand-alone facility, yet 53% of its' staff suffered from GI complaints. Prevention of morbidity and specifically of GI complaints upon arrival to a disaster-stricken area in a developing country is difficult. Medical teams in such missions should be acquainted with treating GI complaints.

Glasgow Coma Scale Score in Survivors of Explosion With Possible Traumatic Brain Injury in Need of Neurosurgical Intervention

IMPORTANCE

Head injury following explosions is common. Rapid identification of patients with severe traumatic brain injury (TBI) in need of neurosurgical intervention is complicated in a situation where multiple casualties are admitted following an explosion.

OBJECTIVE

To evaluate whether Glasgow Coma Scale (GCS) score or the Simplified Motor Score at presentation would identify patients with severe TBI in need of neurosurgical intervention.

DESIGN, SETTING, AND PARTICIPANTS

Analysis of clinical data recorded in the Israel National Trauma Registry of 1081 patients treated following terrorist bombings in the civilian setting between 1998 and 2005. Primary analysis of the data was conducted in 2009, and analysis was completed in 2015.

MAIN OUTCOMES AND MEASURES

Proportion of patients with TBI in need of neurosurgical intervention per GCS score or Simplified Motor Score.

RESULTS

Of 1081 patients (median age, 29 years [range, 0-90 years]; 38.9% women), 198 (18.3%) were diagnosed as having TBI (48 mild and 150 severe). Severe TBI was diagnosed in 48 of 877 patients (5%) with a GCS score of 15 and in 99 of 171 patients (58%) with GCS scores of 3 to 14 (P < .001). In 65 patients with abnormal GCS (38%), no head injury was recorded. Nine of 877 patients (1%) with a GCS score of 15 were in need of a neurosurgical operation, and fewer than 51 of the 171 patients (30%) with GCS scores of 3 to 14 had a neurosurgical operation (P < .001). No difference was found between the proportion of patients in need of neurosurgery with GCS scores of 3 to 8 and those with GCS scores of 9 to 14 (30% vs 27%; P = .83). When the Simplified Motor Score and GCS were compared with respect to their ability to identify patients in need of neurosurgical interventions, no difference was found between the 2 scores.

CONCLUSIONS AND RELEVANCE

Following an explosion in the civilian setting, 65 patients (38%) with GCS scores of 3 to 14 did not experience severe TBI. The proportion of patients with severe TBI and severe TBI in need of a neurosurgical intervention were similar in patients presenting with GCS scores of 3 to 8 and GCS scores of 9 to 14. In this study, GCS and Simplified Motor Score did not help identify patients with severe TBI in need of a neurosurgical intervention.

Untreated Mitral Regurgitation Does Not Affect Survival of Elderly Patients Undergoing TAVI

BACKGROUND

The study aim was to examine the impact of concomitant significant mitral regurgitation (MR) in patients undergoing transcatheter aortic valve implantation (TAVI). TAVI has become an acceptable mode of treatment for high-surgical risk patients with aortic stenosis (AS) requiring valve replacement. A significant number of patients have concomitant MR which cannot be addressed by TAVI alone, and therefore may not be considered candidates for this procedure. A comparison was conducted of results obtained from patients undergoing TAVI with or without MR.

METHODS

Between 2008 and 2013, a total of 164 patients (mean age 81 ± 8 years) underwent TAVI at the authors' institution. Of these patients, 87 (53%) had MR of moderate or greater degree. The groups were similar with respect to age, gender, presence of congestive heart failure, left ventricular function and co-morbid conditions. The logistic EuroSCORE was higher in the MR group (p = 0.02).

RESULTS

Procedural (30-day) mortality was 12% (n = 19) and similar between groups. Kaplan-Meier estimates showed the overall survival at three years to be 68% and 76% for the MR and non-MR groups, respectively (p = 0.6). By Cox regression, age (p = 0.007) and peripheral vascular disease (p = 0.03) were the only predictors of late survival. Regression of MR was seen in patients with functional MR. Neither the presence of MR nor residual MR emerged as predictors of late mortality.

CONCLUSIONS

In elderly patients undergoing TAVI the presence of MR does not impact survival. TAVI should not be withheld from this group of patients because of concomitant MR.

Mobile in Situ Simulation as a Tool for Evaluation and Improvement of Trauma Treatment in the Emergency Department

BACKGROUND

Medical simulation is an increasingly recognized tool for teaching, coaching, training, and examining practitioners in the medical field. For many years, simulation has been used to improve trauma care and teamwork. Despite technological advances in trauma simulators, including better means of mobilization and control, most reported simulation-based trauma training has been conducted inside simulation centers, and the practice of mobile simulation in hospitals' trauma rooms has not been investigated fully.

METHODS

The emergency department personnel from a second-level trauma center in Israel were evaluated. Divided into randomly formed trauma teams, they were reviewed twice using in situ mobile simulation training at the hospital's trauma bay. In all, 4 simulations were held before and 4 simulations were held after a structured learning intervention. The intervention included a 1-day simulation-based training conducted at the Israel Center for Medical Simulation (MSR), which included video-based debriefing facilitated by the hospital's 4 trauma team leaders who completed a 2-day simulation-based instructors' course before the start of the study. The instructors were also trained on performance rating and thus were responsible for the assessment of their respective teams in real time as well as through reviewing of the recorded videos; thus enabling a comparison of the performances in the mobile simulation exercise before and after the educational intervention.

RESULTS

The internal reliability of the experts' evaluation calculated in the Cronbach α model was found to be 0.786. Statistically significant improvement was observed in 4 of 10 parameters, among which were teamwork (29.64%) and communication (24.48%) (p = 0.00005).

CONCLUSION

The mobile in situ simulation-based training demonstrated efficacy both as an assessment tool for trauma teams' function and an educational intervention when coupled with in vitro simulation-based training, resulting in a significant improvement of the teams' function in various aspects of treatment.

[LESSONS FROM PREPAREDNESS OF HOSPITALS TO SNOWSTORMS]

Snowstorms are not a usual scene in Israel, which normally enjoys relatively warm weather, even in the winter. In the last two years we faced three severe snowstorms that had a major impact on the routine daily life in Israel. Roads were blocked, people experienced long electricity power failures, and secondary to slippery conditions, there was more than a threefold increase of orthopedic injuries. These storms confronted hospitals with unique challenges, both medical and logistic. Hospitals must be prepared to cope with the challenge of maintaining continuation of care. We propose four phases of preparedness strategy: at the beginning of the winter, once there is a weather forecast warning, during the storm itself, and returning to norm. This manuscript deals with the lessons learned by two hospitals in Safed and Jerusalem dealing with snowstorms.

Case report: a brain abscess in a disaster zone- beyond the call of duty

We present a case of a child with a suspected brain abscess treated by a military field hospital in post-typhoon Philippines. We review our intervention and decision process both at the field hospital and following his transfer to a referral center. These interventions were critical for his successful outcome.

[Does mitral valve annuloplasty improve long-term survival in patients having moderate ischemic mitral regurgitation undergoing CABG?]

BACKGROUND

The best surgical approach for patients with moderate ischemic mitral regurgitation (IMR) is still undetermined. We examined long term outcomes in patients with moderate IMR undergoing coronary bypass (CABG), and compared outcomes between those undergoing isolated CABG to those undergoing concomitant restrictive annuloplasty.

METHODS

Between the years 1993-2011, 231 patients with moderate IMR underwent CABG: group 1 (n = 186) underwent isolated CABG, group 2 (n = 15) underwent CABG with concomitant mitral valve annuloplasty. Univariate analysis was used to compare baseline parameters. Kaplan-Meier estimates were used to compare survival. Cox multivariate regression was used to determine predictors for late survival. Survival data up to 20 years is 97% complete.

RESULTS

The groups were similar with respect to age, prior MI, LV function, and incidence of atrial fibrillation. Patients undergoing mitral repair had a higher incidence of congestive heart failure (CHF) (p < 0.0001). After surgery more repair patients required use of inotropes (p = 0.0005). Overall operative mortality was 7% and similar between groups. Ten year survival was 55% and 52% for groups 1 and 2 respectively (p = 0.2). Predictors of late mortality included age, CHF, LV dimensions and LV dysfunction. Neither the addition of a mitral procedure and type of ring implanted nor residual MR after surgery, emerged as predictors of survival.

CONCLUSIONS

In patients with moderate ischemic MR, neither operative mortality nor long term survival are affected by the performance of a restrictive annuloplasty. For patients with CHF, mitral repair may be beneficial in terms of survival.

Preoperative hemoglobin and outcomes in patients with CKD undergoing cardiac surgery

BACKGROUND AND OBJECTIVES

Preoperative anemia adversely affects outcomes of cardiothoracic surgery. However, in patients with CKD, treating anemia to a target of normal hemoglobin has been associated with increased risk of adverse cardiac and cerebrovascular events. We investigated the association between preoperative hemoglobin and outcomes of cardiac surgery in patients with CKD and assessed whether there was a level of preoperative hemoglobin below which the incidence of adverse surgical outcomes increases.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This prospective observational study included adult patients with CKD stages 3-5 (eGFR<60 ml/min per 1.73 m(2)) undergoing cardiac surgery from February 2000 to January 2010. Patients were classified into four groups stratified by preoperative hemoglobin level: <10, 10-11.9, 12-13.9, and ≥ 14 g/dl. The outcomes were postoperative AKI requiring dialysis, sepsis, cerebrovascular accident, and mortality.

RESULTS

In total, 788 patients with a mean eGFR of 43.5 ± 3.7 ml/min per 1.73 m(2) were evaluated, of whom 22.5% had preoperative hemoglobin within the normal range (men: 14-18 g/dl; women: 12-16 g/dl). Univariate analysis revealed an inverse relationship between the incidence of all adverse postoperative outcomes and hemoglobin level. Using hemoglobin as a continuous variable, multivariate logistic regression analysis showed a proportionally greater frequency of all adverse postoperative outcomes per 1-g/dl decrement of preoperative hemoglobin (mortality: odds ratio, 1.38; 95% confidence interval, 1.23 to 1.57; P<0.001; sepsis: odds ratio, 1.31; 95% confidence interval, 1.14 to 1.49; P<0.001; cerebrovascular accident: odds ratio, 1.31; 95% confidence interval, 1.00 to 1.67; P=0.03; postoperative hemodialysis: odds ratio, 1.38; 95% confidence interval, 1.11 to 1.75; P<0.01). Moreover, preoperative hemoglobin<12 g/dl was an independent risk factor for postoperative mortality (odds ratio, 2.6; 95% confidence interval, 1.1 to 7.3; P=0.04).

CONCLUSIONS

Similar to the general population, preoperative anemia is associated with adverse postoperative outcomes in patients with CKD. Whether outcomes could be improved by therapeutically targeting higher preoperative hemoglobin levels before cardiac surgery in patients with underlying CKD remains to be determined.

Ethical and clinical dilemmas in patients with head and neck tumors visiting a field hospital in the Philippines

OBJECTIVE

To describe clinical and ethical dilemmas in patients presenting with head and neck (H&N) tumors to a field hospital in the "subacute" period following a typhoon.

METHODS

We retrospectively reviewed charts of H&N patients presenting to an integrated Israeli-Filipino medical facility, which was operated more than 11 days.

RESULTS

Of the 1,844 adult patients examined, 85 (5 percent) presented with H&N tumors. Of those, 70 (82 percent) were females, with a mean age of 43 ± 15 years. Thyroid neoplasms were the most common tumors (68, 80 percent). Despite limited resources, we contributed to the workup and treatment of several patients. To better illustrate our dilemmas, we present four key patients, in whom we favored diagnostic/therapeutic interventions in two, and opted to defer any intervention in two.

CONCLUSIONS

In a relief mission, despite the lack of clinical and pathological staging and questionable continuity of care, surgical interventions can be considered for therapeutic, palliative, and diagnostic purposes.

Comparison between transcatheter and surgical aortic valve replacement: a single-center experience

BACKGROUND AND AIM OF THE STUDY

A comparison was made of the outcomes after transcatheter aortic valve implantation (TAVI) and surgical aortic valve replacement (AVR) in high-risk patients.

METHODS

All patients aged > 75 years that underwent a procedure for severe aortic stenosis with or without coronary revascularization at the authors' institution were included in the study; thus, 64 patients underwent TAVI and 188 underwent AVR. Patients in the TAVI group were older (mean age 84 +/- 5 versus 80 +/- 4 years; p < 0.0001) and had a higher logistic EuroSCORE (p = 0.004).

RESULTS

Six patients (9%) died during the procedure in the TAVI group, and 23 (12%) died in the AVR group (p = 0.5). Predictors for mortality were: age (p < 0.0001), female gender (p = 0.02), and surgical valve replacement (p = 0.01). Gradients across the implanted valves at one to three months postoperatively were lower in the TAVI group (p < 0.0001). Actuarial survival at one, two and three years was 78%, 64% and 64%, respectively, for TAVI, and 83%, 78% and 75%, respectively, for AVR (p = 0.4). Age was the only predictor for late mortality (p < 0.0001).

CONCLUSION

TAVI patients were older and posed a higher predicted surgical risk. Procedural mortality was lower in the TAVI group, but mid-term survival was similar to that in patients undergoing surgical AVR. Age was the only predictor for late survival. These data support the referral of high-risk patients for TAVI.

Very prolonged stay in the intensive care unit after cardiac operations: early results and late survival

BACKGROUND

Prolonged intensive care unit (ICU) stay is a surrogate for advanced morbidity or perioperative complications, and resource utilization may become an issue. It is our policy to continue full life support in the ICU, even for patients with a seemingly grim outlook. We examined the effect of duration of ICU stay on early outcomes and late survival.

METHODS

Between 1993 and 2011, 6,385 patients were admitted to the ICU after cardiac surgery. Patients were grouped according to length of stay in the ICU: group 1, 2 days or less (n = 4,631; 73%); group 2, 3 to 14 days (n = 1,423; 22%); group 3, more than 14 days (n = 331; 5%). Length of stay in ICU for group 3 patients was 38 ± 24 days (range, 15 to 160; median 31). Clinical profile and outcomes were compared between groups.

RESULTS

Patients requiring prolonged ICU stay were older, underwent more complex surgery, had greater comorbidity, and a higher predicted operative mortality (p < 0.0001). They had a higher incidence of adverse events and increased mortality (p < 0.0001). Of the 331 group 3 patients, 60% were discharged: survival of these patients at 1, 3, and 5 years was 78%, 65%, and 52%, respectively. Operative mortality as well as late survival of discharged patients was proportional to duration of ICU stay.

CONCLUSIONS

Current technology enables keeping sick patients alive for extended periods of time. Nearly two thirds of patients requiring prolonged ICU leave hospital, and of these, 50% attain 5-year survival. These data support offering full and continued support even for patients requiring very prolonged ICU stay.

Global responsibility in mass casualty events: the Israeli experience in Japan

OBJECTIVE

To describe humanitarian aid following the 2011 earthquake and tsunami in Japan.

SETTING

A field hospital deployed in a small Japanese coastal village devastated by a major tsunami.

PATIENTS

Thousands of Japanese refugees with minimal access to medical care.

RESULTS

After well-coordinated diplomatic efforts, our medical delegation was the first foreign team to deploy in Japan. Our facility served as a regional referral center for specialized medical treatment.

CONCLUSIONS

Following major disasters, even highly modernized countries will face an urgent surge in the need of medical resources. These situations emphasize the need for global responsibility to provide assistance.

Orthopaedic management in a mega mass casualty situation. The Israel Defence Forces Field Hospital in Haiti following the January 2010 earthquake

Following the January 2010 earthquake in Haiti, the Israel Defence Forces (IDF) established a field hospital in Port au Prince. The hospital started operating 89 h after the earthquake. We describe the experience of the orthopaedic department in a field hospital operating in an extreme mass casualty situation. The hospital contained 4 operating table and 72 hospitalization beds. The orthopaedic department included 8 orthopaedic surgeons and 3 residents. 1111 patients were treated in the hospital, 1041 of them had adequate records for inclusion. 684 patients were admitted due to trauma with a total of 841 injuries. 320 patients sustained 360 fractures, 18 had joint dislocations and 22 patients were admitted after amputations. 207 patients suffered 315 soft tissue injuries. 221 patients were operated on under general or regional anaesthesia. External fixation was used for stabilization of 48 adult femoral shaft fractures, 24 open tibial fractures and 1 open humeral fracture. All none femoral closed fractures were treated non-operatively. 18 joint reductions and 23 amputations were performed. Appropriate planning, training, operational versatility, and adjustment of therapeutic guidelines according to a constantly changing situation, enabled us to deliver optimal care to the maximal number of patients, in an overwhelming mass trauma situation.

Application of information technology within a field hospital deployment following the January 2010 Haiti earthquake disaster

Following the January 2010 earthquake in Haiti, the Israel Defense Force Medical Corps dispatched a field hospital unit. A specially tailored information technology solution was deployed within the hospital. The solution included a hospital administration system as well as a complete electronic medical record. A light-weight picture archiving and communication system was also deployed. During 10 days of operation, the system registered 1111 patients. The network and system up times were more than 99.9%. Patient movements within the hospital were noted, and an online command dashboard screen was generated. Patient care was delivered using the electronic medical record. Digital radiographs were acquired and transmitted to stations throughout the hospital. The system helped to introduce order in an otherwise chaotic situation and enabled adequate utilization of scarce medical resources by continually gathering information, analyzing it, and presenting it to the decision-making command level. The establishment of electronic medical records promoted the adequacy of medical treatment and facilitated continuity of care. This experience in Haiti supports the feasibility of deploying information technologies within a field hospital operation. Disaster response teams and agencies are encouraged to consider the use of information technology as part of their contingency plans.

Early disaster response in Haiti: the Israeli field hospital experience

The earthquake that struck Haiti in January 2010 caused an estimated 230,000 deaths and injured approximately 250,000 people. The Israel Defense Forces Medical Corps Field Hospital was fully operational on site only 89 hours after the earthquake struck and was capable of providing sophisticated medical care. During the 10 days the hospital was operational, its staff treated 1111 patients, hospitalized 737 patients, and performed 244 operations on 203 patients. The field hospital also served as a referral center for medical teams from other countries that were deployed in the surrounding areas. The key factor that enabled rapid response during the early phase of the disaster from a distance of 6000 miles was a well-prepared and trained medical unit maintained on continuous alert. The prompt deployment of advanced-capability field hospitals is essential in disaster relief, especially in countries with minimal medical infrastructure. The changing medical requirements of people in an earthquake zone dictate that field hospitals be designed to operate with maximum flexibility and versatility regarding triage, staff positioning, treatment priorities, and hospitalization policies. Early coordination with local administrative bodies is indispensable.

Hard times call for creative solutions: medical improvisations at the Israel Defense Forces Field Hospital in Haiti

Mass disaster medicine is characterized by the need to manage limited resources that are far inadequate to meet the population's demands. Under these hectic conditions, lack of specific medical equipment is expected and requires improvisation using available items. We describe the innovative use of medical improvisations at the Israel Defense Forces field hospital, working in the earthquake zone, Port-au-Prince, Haiti, on January 2010. Creative solutions were found to several problems in a variety of medical fields: blood transfusion, debridement and coverage of complex wounds, self-production of orthopedic hardware, surgical exposure, and managing maxillofacial injuries. We hope that the methods described will help to inspire medical teams working in disaster regions.

Aortic valve replacement: choice between mechanical valves and bioprostheses

BACKGROUND

The choice between a mechanical or bioprosthetic valve replacement device is not always clear, although patient age is most often the determining factor. We reviewed our experience with patients undergoing aortic valve replacement (AVR) in order to assess and compare long-term outcomes between patients receiving a mechanical valve and those receiving a bioprosthesis.

METHODS

Three hundred fifty-two patients underwent AVR with or without coronary artery bypass between 1993 and 2004: 189 received a mechanical valve and 163 a bioprosthesis. Events included: late mortality, thrombo-embolic events, stroke, bleeding events, valve thrombosis, endocarditis, reoperation, and coronary catheterization.

RESULTS

Patients in the bioprosthesis group were older (71 +/- 11 vs. 65 +/- 13) than in the mechanical group (p < 0.0001). There was no difference in operative mortality (6.8%) or morbidity. Follow-up (61 +/- 40 months) was available in 87%. For mechanical valves and bioprostheses, respectively: 3-, 5-, and 10-year survival was 92%, 86%, and 69% versus 90%, 86%, and 71% (p = n.s.); and event-free survival was 79%, 68%, and 41% versus 79%, 68%, and 44% (p = n.s.). Five patients (3%) in each group required re-replacement of their aortic valve (p = n.s.). Coronary artery disease requiring bypass surgery did not affect long-term survival. Age at operation and renal failure were the only predictors for late mortality.

CONCLUSIONS

Survival and event-free survival are similar for patients receiving a mechanical or biological aortic valve substitute. Selection of a valve replacement device should be based on life expectancy, patient preference, ability to take anticoagulants, lifestyle, risk of bleeding, and risk of reoperation. Patient age alone should not be the determining factor.

[Surgery for ischemic mitral regurgitation: results and long-term follow-up]

BACKGROUND

The natural history of patients with ischemic mitral regurgitation (IMR) shows a poor prognosis. The surgical risk in these patients is high, but affords improved survival. We examined long-term results after coronary bypass and mitral repair for patients with IMR.

METHODS

There were 122 patients operated on between the years 1993-2004. Patient age was 65 +/- 10 years, and 89 (73%) were male. Fifty-one (42%) were in NYHA class IV (mean NYHA class 3.1 +/- 1); 77 (63%) had pre-operative LV function grade 3-4 (mean LV grade 2.8 +/- 1); 103 (84%) had MR grade 4 (mean MR grade 3.8 +/- 0.4). All patients received mitral valve annuloplasty with a flexible ring (size 26 +/- 1 mm). Number of bypass grafts performed was 2.5 +/- 0.9.

RESULTS

Operative mortality was 7% (9 patients). Operative survivors (n = 113) were followed for a mean interval of 34 months (range 2-91). NYHA class was 2.2 +/- 1. In 65 patients (58%) LV function was grade 1-2. Mean MR was 1.6 +/- 1 for the whole group, and 28 (25%) remained with MR grade 3-4. Late mortality was 18% (21 patients) 33 +/- 20 months after surgery (range 2-62). Predictors for late mortality were poor LV function, NYHA class IV, and age > 70 years (p < 0.0001). Overall, residual MR did not emerge as a predictor for late mortality.

CONCLUSIONS

Surgery for patients with IMR can be performed with an acceptable risk. In our patient group, LV function is the major determinant for late survival, overshadowing the effect of residual MR.

[Permanent pacemaker implantation after heart surgery: incidence and indications]

BACKGROUND

New conduction disturbances requiring pacemaker implantation occur in about 1-3% of patients undergoing heart surgery. We reviewed our experience with patients undergoing heart surgery between the years 1993-2005 in order to identify predictors for pacemaker requirement.

METHODS

There were 4999 patients aged 64 +/- 12 years. Coronary bypass was performed in 3448 (69%), valve surgery in 831 (17%), combined procedures in 623 (12%), and other procedures in 97 (2%).

RESULTS

Overall, 72 (1.4%) patients required pacemaker implantation for the following indications: complete atrioventricular block (AVB) in 59, second degree AVB in 2, severe bradycardia (< 40 beats/min) in 9, first degree AVB with left bundle branch block (LBBB) in 1, and bifascicular block in 1. For patients undergoing aortic valve replacement, the incidence of pacemaker implantation was 5%. Multivariate analysis identified the following predictors for pacemaker implantation: LBBB, aortic valve replacement, and elevated CPK-MB levels after surgery.

CONCLUSIONS

Patients undergoing heart surgery will require a permanent pacemaker in about 1.4% of cases. Based upon the recognition of predictors for pacemaker requirement, we recommend early implantation in order to enable early mobilization and shorter hospital stay.

[Pleural effusion following coronary bypass surgery]

BACKGROUND

Pleural effusion is a common finding after coronary artery bypass surgery (CABG). We sought to determine the incidence and patient characteristics predictive of its appearance, in addition to the effect of post-operative treatment with enoxaparin.

METHODS

We retrospectively examined 893 patients undergoing CABG: 520 consecutive patients did not receive enoxaparin, and 373 patients received it. All early (up to 10 days) peri-operative chest radiograms were examined and graded by the amount of pleural effusion: (i) small--obliteration of the costophrenic angle; (ii) moderate-- < 50% of lung field; (iii) large-- > 50% of lung field. Patient characteristics as well as operative and post-operative parameters were analyzed in order to identify predictors for pleural effusion.

RESULTS

Pleural effusion was small in 415 patients (46%), moderate in 346 (39%) and large in 132 (15%). Older age, female gender and congestive heart failure were found to be predictors for pleural effusion by multi-variate analysis (p <0.05). Routine use of enoxaparin was not found to be associated with pleural effusion after CABG.

CONCLUSIONS

Over 50% of patients will develop a significant pleural effusion following CABG. Prophylactic treatment with enoxaparin does not increase the risk for pleural effusion.

Ozone administration reduces reperfusion injury in an isolated rat heart model

BACKGROUND

Accumulating clinical experience with ozone administration for conditions associated with ischemia has been encouraging. The aim of our study was to determine the effect of ozone on reperfusion injury in an isolated rat heart model.

METHODS

Isolated rat hearts were perfused with modified Krebs-Henseleit buffer solution via ascending aorta cannulation. After 15 minutes, perfusion was stopped and global ischemia was maintained for 30 minutes, following which perfusion was restarted, and continued for 40 minutes. Baseline hemodynamic measurements (heart rate, left ventricular developed pressure (LVDP), dP/dt, and coronary flow) were taken prior to ischemia, and every 10 minutes after reperfusion was started. Eleven hearts were treated with ozone during reperfusion and eight hearts served as controls. In the treatment group, after 5 minutes of reperfusion, ozone was administered in distilled water via a side arm for 5 minutes.

RESULTS

Preischemic baseline hemodynamic measurements and coronary flow were similar in the two groups. Hearts treated with ozone during reperfusion exhibited better recovery than did controls. Mean (+/-SE) percent recovery for treatment and control groups, respectively, was: LVDP 69 +/- 2% vs 51 +/- 6% (p = 0.04); dP/dt 68.9 +/- 13.3% vs 53.7 +/- 20.4% (p = 0.05); and LVDPxHR 61.4 +/- 3.3% vs 44.4 +/- 3.5% (p = 0.02).

CONCLUSION

In the isolated rat heart model, treatment with ozone during reperfusion enables better recovery than in controls. Although the mechanism by which ozone exerts its beneficial effect is not identified, it is possibly due to reduction in reperfusion injury.

Does mitral valve intervention have an impact on late survival in ischemic cardiomyopathy?

BACKGROUND

Ischemic mitral regurgitation is associated with reduced survival after coronary artery bypass surgery.

OBJECTIVES

To compare long-term survival among patients undergoing coronary surgery for reduced left ventricular function and severe ischemic MR in whom the valve was repaired, replaced, or no intervention was performed.

METHODS

Eighty patients with severe left ventricular dysfunction and severe MR underwent coronary bypass surgery. The mean age of the patients was 65 years (range 42-82), and 63 (79%) were male. Sixty-three (79%) were in preoperative NYHA functional class III-IV (mean NYHA 3.3), and 26 (32%) were operated on an urgent/emergent basis. Coronary artery bypass surgery was performed in all patients. The mitral valve was repaired in 38 and replaced in 14, and in 28 there was no intervention. The clinical profile was similar in the three groups, although patients undergoing repair were slightly younger.

RESULTS

Operative mortality was 15% (8%, 14%, and 25% for the repair, replacement and no intervention respectively; not significant). Long-term follow up was 100% complete, for a mean of 38 months (range 2-92). Twenty-nine patients (57%) were in NYHA I-II (mean NYHA 2.3). Among the surgery survivors, late survival was improved in the repair group compared to the other groups (P < 0.05). Predictors for late mortality were non-repair of the mitral valve, residual MR, and stroke (P = 0.005).

CONCLUSIONS

Patients with severe ischemic cardiomyopathy and severe MR undergoing coronary bypass surgery should have a mitral procedure at the time of surgery. Mitral valve repair offers a survival advantage as compared to replacement or no intervention on the valve. Patients with residual MR had the worst results.

Latent infective endocarditis: epidemiology and clinical characteristics of patients with unsuspected endocarditis detected after elective valve replacement

BACKGROUND

The diagnosis of infective endocarditis is usually made on the basis of clinical and laboratory criteria and may be confirmed by histologic examination or culture of excised valves. We tried to determine the incidence and significance of inflammatory changes in valves excised during operations for reasons other than infective endocarditis.

METHODS

The charts and histopathology of all patients undergoing valve replacement during a 10-year period (1993-2002) were reviewed. A total of 868 patients underwent a total of 970 valve replacements during this period, of whom 11 patients (1.3%) were for endocarditis, with the remaining 857 (98.7%) for other indications. All excised valves were cultured and examined histologically for the presence of inflammatory infiltrates, vegetations, and microorganisms.

RESULTS

In 8 of 857 patients (0.9%), the histologic examination unexpectedly demonstrated an infiltrate suggestive of endocarditis. Blood and valve cultures, and serologic tests for Mycoplasma, Chlamydia, Legionella, Q fever, Brucella, Rickettsiae, VDRL, and Bartonella were negative in all but 1 patient, who was found to have Q fever. All received a prolonged course of antibiotics. Six patients had an uneventful recovery; 1 had intramyocardial abscesses and expired during cardiac reoperation; and 1 had recurrent fever and dehiscence of the aortic and mitral valve prostheses and after two cardiac reoperations remains in severe heart failure.

CONCLUSIONS

The presence of an unexpected inflammatory infiltrate in heart valves excised for reasons other than endocarditis may occur in 0.9% of such operations; these infiltrates could indicate presence of endocarditis. A microbial origin should be sought, and patients should receive empiric antibiotic treatment for endocarditis.

Long-Term Results of Aortic Valve Replacement With the St. Jude Toronto Stentless Porcine Valve

BACKGROUND

Long-term survival and freedom from valve-related events of the St. Jude Toronto stentless porcine valve (SPV) are unknown. The aim of this study was to investigate late clinical outcomes after aortic valve replacement with the Toronto SPV.

METHODS

Between 1992 and 2000, 200 patients (131 males, 69 females) underwent aortic valve replacement with the Toronto SPV. Mean patient age at implantation was 64.6 +/- 10.9 years (range 33 to 82 years). At the time of operation, 32%, 51%, and 17% of patients were in New York Heart Association class I/II, III, and IV, respectively. Aortic stenosis, aortic insufficiency, and combined lesions were present in 64%, 13.5%, and 22.5% of patients preoperatively. Concomitant coronary artery bypass grafting was performed in 34.5% of patients.

RESULTS

Perioperative mortality occurred in 2.5% (5/200) of patients. There were 31 late deaths. Actuarial survival at 5 and 10 years was 89.2% and 68.0%, respectively. There was no significant difference in overall actuarial survival between isolated valve patients and valve plus coronary artery bypass grafting patients, 71% versus 62% respectively, p = 0.85. Actuarial freedom from valve reoperation at 5 and 10 years was 97.6% and 79.9%, respectively. Actuarial freedom from structural valve deterioration was 98.8% at 5 years and declined to 77.9% at 10 years. Freedom from structural valve deterioration was poorer in patients with preoperative aortic insufficiency or bicuspid disease. Actuarial freedom from embolic events and endocarditis at 10 years were 94.6% and 95.9%, respectively.

CONCLUSIONS

Although early clinical results were excellent, a significant increase in hazard for structural valve deterioration occurred in late follow-up.

Does coronary endarterectomy increase the risk of coronary bypass?

BACKGROUND

With increased incidence of angioplasty and stent implantation, patients referred for coronary bypass (CABG) typically have more advanced and diffuse coronary disease. Thus, more patients may require endarterectomy in order to achieve complete revascularization. We compared our results in patients undergoing CABG with or without coronary endarterectomy.

METHODS

Between 1993 and 1999, 2372 patients underwent isolated CABG in our department. A retrospective analysis was performed to compare patients requiring coronary endarterectomy of the LAD (group 1, n = 88), endarterectomy of arteries other than the LAD (group 2, n = 143), to those not requiring endarterectomy (group 3, n = 2071). Patients undergoing CABG without the use of cardiopulmonary bypass were excluded. Group 1 had a higher incidence of proximal LAD stenosis (p = 0.001) than group 3, while group 2 had a higher incidence of peripheral vascular disease (p = 0.02), preoperative MI (p = 0.03) and LV dysfunction (p = 0.001).

RESULTS

Operative mortality was 10% in group 1 (p < 0.001) and 4% in group 2 (p = NS) compared to 3% in group 3. Incidence of perioperative MI was 12% in group 1 (p = 0.001) and 8% in group 2 (p = 0.001) compared to 2% in group 3.

CONCLUSIONS

Patients requiring endarterectomy of the LAD are at increased risk of operative mortality. This was not true for patients requiring endarterectomy of arteries other than the LAD. In both groups there was an increased risk of perioperative myocardial infarction.

Aortic valve replacement under deep hypothermic circulatory arrest

BACKGROUND

Aortic valve replacement (AVR) in the presence of a calcified aorta or patent grafts may preclude clamping of the ascending aorta. We employed deep hypothermic circulatory arrest in order to circumvent this problem.

METHODS

Between January 1993 and December 2000, 415 patients underwent AVR in our department. Eight of these were operated using deep hypothermic circulatory arrest. There were 5 males, and mean age was 72 years (range 56-81). Indications for using circulatory arrest were reoperation with patent grafts and/or severe calcification of the ascending aorta. In six patients, cardiopulmonary bypass was achieved via femoro-femoral bypass, and in two via aortic-right atrial cannulation. Retrograde cerebral perfusion was employed in five. Mean bypass time was 155 minutes (range 122-187), and mean circulatory arrest time was 38 minutes (range 31-49).

RESULTS

There was no operative mortality, and no patient suffered any neurologic sequelae. Echocardiography showed all valves to be functioning well.

CONCLUSIONS

AVR under deep hypothermic circulatory arrest can be accomplished with an acceptable degree of safety. It should be considered as an alternative in patients in whom aortic clamping is prohibitive, and might otherwise be considered inoperable. The ability to connect the patient to bypass and the presence of a "window" to allow aortotomy are prerequisites for employing this method.

Exercise hemodynamics of aortic prostheses: comparison between stentless bioprostheses and mechanical valves

BACKGROUND

Nonstented bioprostheses have been associated with lower resting gradients than stented bioprostheses or mechanical valves. We compared the hemodynamic performance of nonstented bioprostheses and mechanical valves with normal native aortic valves at rest and exercise.

METHODS

Dobutamine echocardiography was used to assess gradients and effective orifice area index at rest and exercise in patients with the Toronto stentless porcine valve (TSPV; n = 13; mean implant size 25.7 mm), Medtronic Freestyle (FR; n = 11; mean implant size 23.9 mm), Sorin Bicarbon (SOR; n = 11; mean implant size 24.5 mm), St. Jude Medical (SJM; n = 10; mean implant size 21.3 mm), and normal native aortic valves (NOR; n = 10).

RESULTS

All groups demonstrated a major rise in cardiac output at maximal dobutamine infusion. At rest and exercise, respectively, mean gradients were 5.48 +/- 1.1 mm Hg and 5.83 +/- 0.9 mm Hg for TSPV, 5.68 +/- 1.2 mm Hg and 7.50 +/- 1.7 mm Hg for FR, 10.29 +/- 1.4 mm Hg and 20.78 +/- 2.7 mm Hg for SJM, 5.26 +/- 0.8 mm Hg and 11.1 +/- 1.8 mm Hg for SOR, and 1.54 +/- 0.4 mm Hg and 2.18 +/- 0.7 mm Hg for NOR. In comparison with normal valves, both stentless groups showed no change in mean gradient at exercise, whereas both mechanical groups showed an increase in gradient at exercise (p < 0.04).

CONCLUSIONS

Stentless valves behave similarly to normal aortic valves in that there is almost no increase in gradient at exercise. Both mechanical valve groups showed increased gradients at exercise, suggesting that these valves obstruct blood flow. Our data add further evidence that stentless valves are hemodynamically superior to mechanical valves in the aortic position.