Depression and poor outcome after an acute coronary event: Clarification of risk periods and mechanisms

OBJECTIVE

Lifetime depression and depression around the time of an acute coronary syndrome event have been associated with poor cardiac outcomes. Our study sought to examine the persistence of this association, especially given modern cardiac medicine's successes.

METHODS

For 332 patients admitted for an acute coronary syndrome, a baseline interview assessed major depression status, and psychological measures were administered. At 1 and 12 months post-acute coronary syndrome event, telephone interviews collected rates of hospital readmission and/or death and major depression status, while biomarker information was examined using medical records.

RESULTS

The 12-month mortality rate was 2.3% and cardiac readmission rate 21.0%. Depression subsequent to an acute coronary syndrome event resulted in a threefold and 2.5-fold increase in 1-month and 12-month odds of cardiac readmission or death, respectively. No relationship with past depressive episodes was found. Poor sleep was associated with higher trait anxiety and neuroticism scores and with more severe depression.

CONCLUSION

Lifetime depression may increase the risk of depression around the time of an acute coronary syndrome but not influence cardiac outcomes. We suggest that poor sleep quality may be causal or indicate high anxiety/neuroticism, which increases risk to depression and contributes to poor cardiac outcomes rather than depression being the primary causal factor.

Outcomes after mitral valve surgery for rheumatic heart disease

Objective

To further the understanding of the factors influencing outcome following rheumatic heart disease (RHD) related mitral valve surgery, which globally remains an important cause of heart disease and a particular problem in Indigenous Australians.

Methods

The Australian Cardiac Surgery Database was utilised to assess outcomes following mitral valve repair and replacement for RHD and non-RHD valve disease. The association with aetiology, demographics, comorbidities, preoperative status and operative procedure was evaluated.

Results

Mitral valve repairs and replacements undertaken in Australia were analysed from 119 and 1078 RHD surgical procedures and 3279 and 2400 non-RHD procedures, respectively. RHD mitral valve repair, compared with replacement, resulted in a slightly shorter hospital stay and more reoperation for valve dysfunction, but no difference in 30-day survival. In unadjusted survival analysis to 5 years, RHD mitral valve repair and replacement were no different (HR 0.86, 95% CI 0.4 to 1.7), non-RHD repair was superior to replacement (HR 1.7, 95% CI 1.4 to 2.0), RHD and non-RHD repair were no different (HR 0.9, 95% CI 0.5 to 1.7), and RHD replacement was superior to non-RHD (HR 1.5, 95% CI 1.2 to 1.9). None of these differences persisted in adjusted analyses and there was no difference in long-term survival for Indigenous Australians.

Conclusion

In this large prospective cohort study we have demonstrated that adjusted long-term survival following RHD mitral valve repair surgery in Australia is no different to replacement and no different to non-RHD. Interpretation of valve surgery outcome requires careful consideration of patient factors that may also influence survival.

Outcome following valve surgery in Australia: development of an enhanced database module

BACKGROUND

Valvular heart disease, including rheumatic heart disease (RHD), is an important cause of heart disease globally. Management of advanced disease can include surgery and other interventions to repair or replace affected valves. This article summarises the methodology of a study that will incorporate enhanced data collection systems to provide additional insights into treatment choice and outcome for advanced valvular disease including that due to RHD.

METHODS

An enhanced data collection system will be developed linking an existing Australian cardiac surgery registry to more detailed baseline co-morbidity, medication, echocardiographic and hospital separation data to identify predictors of morbidity and mortality outcome following valve surgery.

DISCUSSION

This project aims to collect and incorporate more detailed information regarding pre and postoperative factors and subsequent morbidity. We will use this to provide additional insights into treatment choice and outcome.

Case load and valve surgery outcome in Australia

BACKGROUND

In Australia it has been suggested that heart valve surgery, particularly for rheumatic heart disease (RHD), should be consolidated in higher volume centres. International studies of cardiac surgery suggest large volume centres have superior outcomes. However the effect of site and surgeon case load on longer term outcomes for valve surgery has not been investigated.

METHODS

The Australian and New Zealand Society of Cardiac and Thoracic Surgeons Cardiac Surgery Database was analysed. The adjusted association between both average annual site and surgeon case load on short term complications and short and long-term survival was determined.

RESULTS

Outcomes associated with 20,116 valve procedures at 25 surgical sites and by 93 surgeons were analysed. Overall adjusted analysis showed increasing site and surgeon case load was associated with longer ventilation, less reoperation and more anticoagulant complications. Increasing surgeon case load was also associated with less acute kidney injury. Adjusted 30-day mortality was not associated with site or surgeon case load. There was no consistent relationship between increasing site case load and long term survival. The association between surgeon case load and outcome demonstrated poorer adjusted survival in the highest volume surgeon group.

CONCLUSIONS

In this Australian study, the adjusted association between surgeon and site case load was not simple or consistent. Overall larger volume sites or surgeons did not have superior outcomes. Mandating a particular site case load level for valve surgery or a minimum number of procedures for individual surgeons, in an Australian context, cannot be supported by these findings.

A review of outcome following valve surgery for rheumatic heart disease in Australia

Background

Globally, rheumatic heart disease (RHD) remains an important cause of heart disease. In Australia it particularly affects younger Indigenous and older non-Indigenous Australians. Despite its impact there is limited understanding of the factors influencing outcome following surgery for RHD.

Methods

The Australian and New Zealand Society of Cardiac and Thoracic Surgeons Cardiac Surgery Database was analysed to assess outcomes following surgical procedures for RHD and non-RHD valvular disease. The association with demographics, co-morbidities, pre-operative status, valve(s) affected and operative procedure was evaluated.

Results

Outcome of 1384 RHD and 15843 non-RHD valve procedures was analysed. RHD patients had longer ventilation, experienced fewer strokes and had more readmissions to hospital and anticoagulant complications. Mortality following RHD surgery at 30 days was 3.1 % (95 % CI 2.2 – 4.3), 5 years 15.3 % (11.7 – 19.5) and 10 years 25.0 % (10.7 – 44.9). Mortality following non-RHD surgery at 30 days was 4.3 % (95 % CI 3.9 - 4.6), 5 years 17.6 % (16.4 - 18.9) and 10 years 39.4 % (33.0 - 46.1). Factors independently associated with poorer longer term survival following RHD surgery included older age (OR1.03/additional year, 95 % CI 1.01 – 1.05), concomitant diabetes (OR 1.7, 95 % CI 1.1 – 2.5) and chronic kidney disease (1.9, 1.2 – 2.9), longer invasive ventilation time (OR 1.7 if greater than median value, 1.1– 2.9) and prolonged stay in hospital (1.02/additional day, 1.01 – 1.03). Survival in Indigenous Australians was comparable to that seen in non-Indigenous Australians.

Conclusion

In a large prospective cohort study we have demonstrated survival following RHD valve surgery in Australia is comparable to earlier studies. Patients with diabetes and chronic kidney disease, were at particular risk of poorer long-term survival. Unlike earlier studies we did not find pre-existing atrial fibrillation, being an Indigenous Australian or the nature of the underlying valve lesion were independent predictors of survival.

Timing is everything: the onset of depression and acute coronary syndrome outcome

BACKGROUND

Conflicting findings have emerged from studies examining the impact of depression on death and readmission following a coronary event, possibly reflecting differences in the measurement of "depression" and the onset of depression in relation to the coronary event. The aim of this study was to examine the relationship between the timing of the depressive episode and 1-year cardiovascular outcome in recruited patients with acute coronary syndrome (ACS).

METHODS

Patients hospitalized with ACS (N = 489) were recruited and assessed for lifetime and current depression by the Composite International Diagnostic Interview (CIDI) depression schedule. Patients were reinterviewed at 1 and 12 months by telephone to assess depression status and cardiovascular outcomes (ACS readmission and cardiac mortality). Mortality registers were also checked.

RESULTS

Cardiovascular outcome was not associated with the presence of lifetime depression before the ACS admission or with existing depression at the time of the ACS admission. In contrast, depression that developed in the month after the ACS event showed a strong relationship with subsequent cardiovascular outcome, even after controlling for traditional cardiac risk factors. Outcome over the 12 months was more strongly predicted by the timing of depression onset than whether the depression was a first-ever (incident) or recurrent episode.

CONCLUSIONS

Only a depressive episode that commenced following an ACS admission was associated with a poorer cardiovascular outcome. If confirmed, this finding would narrow the list of causal mechanisms previously proposed to account for the relationship between depression and coronary events.

Low levels of docosahexaenoic acid identified in acute coronary syndrome patients with depression

As deficiencies in n-3 PUFAs have been linked separately to depression and to cardiovascular disease, they could act as a higher order variable contributing to the established link between depression and cardiovascular disease. We therefore examine the relationship between depression and omega-3 polyunsaturated fatty acids (n-3 PUFA), including total n-3 PUFA, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), in patients with acute coronary syndrome (ACS). Plasma phospholipid levels of n-3 PUFA were measured in 100 patients hospitalized with ACS. Current major depressive episode was assessed by the Composite International Diagnostic Interview (CIDI). Depression severity was assessed by the 18-item Depression in the Medically Ill (DMI-18) measure. Patients clinically diagnosed with current depression had significantly lower mean total n-3 PUFA and DHA levels. Higher DMI-18 depression severity scores were significantly associated with lower DHA levels, with similar but non-significant trends observed for EPA and total n-3 PUFA levels. The finding that low DHA levels were associated with depression variables in ACS patients may explain links demonstrated between cardiovascular health and depression, and may have prophylactic and treatment implications.

A Validation Study of Two Brief Measures of Depression in the Cardiac Population: The DMI-10 and DMI-18

The authors report on the psychometric characteristics and clinical efficacy of two versions of a recently developed screening measure of depression (the DMI-18 and DMI-10) in the cardiac population. Patients with acute coronary syndrome or heart failure (N = 322) completed the DMI measures, psychosocial questionnaires, and a semistructured clinical interview during the hospital stay. The DMI-18 and DMI-10 measures have adequate psychometric properties, demonstrating high sensitivity and specificity when evaluated against clinical judgment based on a semistructured interview. The DMI-18 and DMI-10 are appropriate for use as screening instruments in cardiac patients.

Explicating links between acute coronary syndrome and depression: study design and methods

OBJECTIVE

To describe a regional study seeking to replicate the suggested strong links whereby lifetime and post-coronary infarction depression are associated with a significant increase in mortality and cardiac morbidity, and consider the comparative influence of both depression and anxiety.

METHOD

We detail relevant international studies and describe both the methodology as well as baseline and 1-month data from our study.

RESULTS

Over a 3-year period we recruited 489 subjects admitted to a Sydney cardiac unit with an Acute Coronary Syndrome (ACS), and assessed by a range of cardiac variables and measures of current and lifetime depression. Ninety-eight per cent of the sample were assessed one month after baseline recruitment to establish depression rates. Long-term outcome reviews of mortality and morbidity and hospitalization rates are proceeding. For those subjects who were depressed in the post-ACS period and, even more so for those who had experienced lifetime depression, distinctly higher scores on anxiety variables (and lifetime caseness for anxiety disorders) were established.

CONCLUSIONS

The strong interdependence between anxiety and depression in this sample of patients admitted with an ACS will allow examination of the comparative extent to which expressions of 'depression' and 'anxiety' contribute to post-ACS morbidity.

Rates of percutaneous coronary interventions and bypass surgery after acute myocardial infarction in Indigenous patients

OBJECTIVE

To compare rates of percutaneous coronary interventions (PCI) and bypass surgery after acute myocardial infarction (AMI) in Indigenous and non-Indigenous patients.

DESIGN

Cohort study of public-sector patients who were followed up for 1 year using administrative hospital data.

PARTICIPANTS AND SETTING

We followed up 14 683 public-sector patients admitted to Queensland hospitals for AMI between 1998 and 2002. Of these, 558 (3.8%) identified as Indigenous.

OUTCOME MEASURES

Rates of PCI and bypass surgery, adjusted for differences between the Indigenous and non-Indigenous cohorts according to age, sex, socioeconomic status, remote residence, hospital characteristics, and comorbidities.

RESULTS

The adjusted rate for PCI during the index admission was significantly lower by 39% (rate ratio [RR], 0.61; 95% CI, 0.38-0.98) among Indigenous versus non-Indigenous patients with AMI; the adjusted rate for subsequent PCI was significantly lower by 28% (RR, 0.72; 95% CI, 0.54-0.96). Adjusted rates for bypass surgery were similar in the two cohorts. For any coronary procedure (ie, PCI or bypass surgery), the adjusted rate was significantly lower by 22% (RR, 0.78; 95% CI, 0.64-0.94) among Indigenous patients with AMI. Diabetes, chronic renal failure, pneumonia, and chronic rheumatic fever were at least twice as common among Indigenous patients with AMI as in the rest of the cohort, and chronic bronchitis and emphysema and heart failure were at least 60% more common. If a patient had at least one comorbidity, then their probability of having a coronary procedure was reduced by 40%.

CONCLUSIONS

There are likely to be several reasons for the lower rates of coronary procedures among Indigenous patients, but their high rates of comorbidities and the association of comorbidities with lower procedure rates was an important finding. As investment in primary care can reduce the prevalence and severity of comorbidities, we suggest that adequate primary health care is a prerequisite for effective specialist care.

Neonatal pulmonary hypertension--urea-cycle intermediates, nitric oxide production, and carbamoyl-phosphate synthetase function

BACKGROUND

Endogenous production of nitric oxide is vital for the decrease in pulmonary vascular resistance that normally occurs after birth. The precursor of nitric oxide is arginine, a urea-cycle intermediate. We hypothesized that low concentrations of arginine would correlate with the presence of persistent pulmonary hypertension in newborns and that the supply of this precursor would be affected by a functional polymorphism (the substitution of asparagine for threonine at position 1405 [T1405N]) in carbamoyl-phosphate synthetase, which controls the rate-limiting step of the urea cycle.

METHODS

Plasma concentrations of amino acids and genotypes of the carbamoyl-phosphate synthetase variants were determined in 65 near-term neonates with respiratory distress. Plasma nitric oxide metabolites were measured in a subgroup of 10 patients. The results in infants with pulmonary hypertension, as assessed by echocardiography, were compared with those in infants without pulmonary hypertension. The frequencies of the carbamoyl-phosphate synthetase genotypes in the study population were assessed for Hardy-Weinberg equilibrium.

RESULTS

As compared with infants without pulmonary hypertension, infants with pulmonary hypertension had lower mean (+/-SD) plasma concentrations of arginine (20.2+/-8.8 vs. 39.8+/-17.0 micromol per liter, P<0.001) and nitric oxide metabolites (18.8+/-12.7 vs. 47.2+/-11.2 micromol per liter, P=0.05). As compared with the general population, the infants in the study had a significantly skewed distribution of the genotypes for the carbamoyl-phosphate synthetase variants at position 1405 (P<0.005). None of the infants with pulmonary hypertension were homozygous for the T1405N polymorphism.

CONCLUSIONS

Infants with persistent pulmonary hypertension have low plasma concentrations of arginine and nitric oxide metabolites. The simultaneous presence of diminished concentrations of precursors and breakdown products suggests that inadequate production of nitric oxide is involved in the pathogenesis of neonatal pulmonary hypertension. Our preliminary observations suggest that the genetically predetermined capacity of the urea cycle--in particular, the efficiency of carbamoyl-phosphate synthetase--may contribute to the availability of precursors for nitric oxide synthesis.

In utero repair of myelomeningocele: a comparison of endoscopy and hysterotomy

OBJECTIVE

To compare endoscopic coverage of myelomeningocele with a maternal split-thickness skin graft in utero to definitive neurosurgical closure through a hysterotomy.

METHODS

Four fetuses with isolated myelomeningocele underwent endoscopic coverage of the defect with a maternal split-thickness skin graft in a CO(2) environment at 22-24 weeks' gestation. Subsequently, 4 fetuses underwent standard neurosurgical closure of their myelomeningoceles at 28-29 weeks' gestation.

RESULTS

The mean operating time for the endoscopic procedures was 297 +/- 69 min. Two fetal losses occurred as a result of chorioamnionitis and placental abruption, respectively. A third baby delivered at 28 weeks' gestation after prolonged disruption of the membranes. The 2 survivors required standard closure of the myelomeningocele after delivery. The mean operating time for the hysterotomy procedures was 125 +/- 8 min. No mortality occurred, and all the infants delivered between 33 and 36 weeks with well-healed myelomeningocele scars. At present, the functional levels of all infants approximate the anatomical levels of the lesions.

CONCLUSION

With current technology, in utero repair of congenital myelomeningocele through a hysterotomy appears to be technically superior to procedures performed endoscopically.

Fetal surgery for myelomeningocele and the incidence of shunt-dependent hydrocephalus

CONTEXT

Intrauterine closure of exposed spinal cord tissue prevents secondary neurologic injury in animals with a surgically created spinal defect; however, whether in utero repair of myelomeningocele improves neurologic outcome in infants with spina bifida is not known.

OBJECTIVE

To determine whether intrauterine repair of myelomeningocele improves patient outcomes compared with standard care.

DESIGN

Single-institution, nonrandomized observational study conducted between January 1990 and February 1999.

SETTING

Tertiary care medical center.

PARTICIPANTS

A sample of 29 study patients with isolated fetal myelomeningocele referred for intrauterine repair that was performed between 24 and 30 gestational weeks and 23 controls matched to cases for diagnosis, level of lesion, practice parameters, and calendar time. All infants were followed up for a minimum of 6 months after delivery.

MAIN OUTCOME MEASURES

Requirement for ventriculoperitoneal shunt placement, obstetrical complications, gestational age at delivery, and birth weight for study vs control subjects.

RESULTS

The requirement for ventriculoperitoneal shunt placement for decompression of hydrocephalus was significantly decreased among study infants (59% vs 91%; P = .01). The median age at shunt placement was also older among study infants (50 vs 5 days; P = .006). This may be explained by the reduced incidence of hindbrain herniation among study infants (38% vs 95%; P<.001). Following hysterotomy, study patients had an increased risk of oligohydramnios (48% vs 4%; P = .001) and admission to the hospital for preterm uterine contractions (50% vs 9%; P = .002). The estimated gestational age at delivery was earlier for study patients (33.2 vs 37.0 weeks; P<.001), and the birth weight of study neonates was less (2171 vs 3075 g; P<.001).

CONCLUSIONS

Our study suggests that intrauterine repair of myelomeningocele decreases the incidence of hindbrain herniation and shunt-dependent hydrocephalus in infants with spina bifida, but increases the incidence of premature delivery.

Effect of intrauterine myelomeningocele repair on central nervous system structure and function

BACKGROUND

It has been postulated that intrauterine myelomeningocele repair might improve neurologic outcome in patients with myelomeningocele. A total of 59 such procedures have been performed at Vanderbilt University. Preliminary results suggested that the degree of hindbrain herniation is reduced by intrauterine repair. In an attempt to further quantify the possible benefits of this surgery, a subset of these patients was brought back to Vanderbilt for study.

METHODS

A group of 26 patients who had undergone intrauterine myelomeningocele repair underwent an extensive evaluation which included manual muscle testing, MR imaging and precise determination of the anatomic level of their lesions as well as multiple other tests. The results of this analysis were compared to those in 2 groups of historical controls.

RESULTS

In this group of patients intrauterine myelomeningocele repair substantially reduced the incidence of moderate to severe hindbrain herniation (4 vs. 50%). The incidence of shunt-dependent hydrocephalus was more modestly reduced (58 vs. 92%). The average level of leg function closely matched the average anatomic level of the lesion in both the fetal surgery and control groups.

CONCLUSION

The most dramatic effect of intrauterine repair appears to be on hindbrain herniation. A less dramatic, but significant, reduction in shunt-dependent hydrocephalus is also seen. Prospective patients should be cautioned not to expect improvement in leg function as the result of this surgery. The potential benefits of surgery must be carefully weighed against the potential risks of prematurity.

Inhaled nitric oxide in premature neonates with severe hypoxaemic respiratory failure: a randomised controlled trial

BACKGROUND

Inhaled nitric oxide improves oxygenation and lessens the need for extracorporeal-membrane oxygenation in full-term neonates with hypoxaemic respiratory failure and persistent pulmonary hypertension, but potential adverse effects are intracranial haemorrhage and chronic lung disease. We investigated whether low-dose inhaled nitric oxide would improve survival in premature neonates with unresponsive severe hypoxaemic respiratory failure, and would not increase the frequency or severity of intracranial haemorrhage or chronic lung disease.

METHODS

We did a double-blind, randomised controlled trial in 12 perinatal centres that provide tertiary care. 80 premature neonates (gestational age < or = 34 weeks) with severe hypoxaemic respiratory failure were randomly assigned inhaled nitric oxide (n=48) or no nitric oxide (n=32, controls). Our primary outcome was survival to discharge. Analysis was by intention to treat. We studied also the rate and severity of intracranial haemorrhage, pulmonary haemorrhage, duration of ventilation, and chronic lung disease at 36 weeks' postconceptional age.

FINDINGS

The two groups did not differ for baseline characteristics or severity of disease. Inhaled nitric oxide improved oxygenation after 60 min (p=0.03). Survival at discharge was 52% in the inhaled-nitric-oxide group and 47% in controls (p=0.65). Causes of death were mainly related to extreme prematurity and were similar in the two groups. The two groups did not differ for adverse events or outcomes (intracranial haemorrhage grade 2-4, 28% inhaled nitric oxide and 33% control; pulmonary haemorrhage 13% and 9%; chronic lung disease 60% and 80%).

INTERPRETATION

Low-dose inhaled nitric oxide improved oxygenation but did not improve survival in severely hypoxaemic premature neonates. Low-dose nitric oxide in the most critically ill premature neonates does not increase the risk of intracranial haemorrhage, and may decrease risk of chronic lung injury.

The decreasing incidence and severity of retinopathy of prematurity

PURPOSE

We sought to determine whether the incidence of retinopathy of prematurity (ROP) at our institution has changed since the Cryo-ROP recruitment period 10 years ago.

METHODS

We determined the incidences of threshold ROP, prethreshold ROP, less-than-prethreshold ROP, and no disease for each of 3 birth weight classes (<750 g, 750 to 999 g, and 1000 to 1250 g) of infants born between July 1, 1995, and June 30, 1996, and cared for in the Vanderbilt Neonatal Intensive Care Unit. We then compared these with the rates from our institution during the Cryo-ROP study recruitment period (January 1, 1986, to November 30, 1987).

RESULTS

The current incidence and severity of ROP have decreased substantially overall and for each weight group compared with the 1986-87 incidence (P < .001, Cochran-Mantel-Haenszel test). The incidence of "any ROP" decreased by 27% for infants with birth weights less than 750 g, by 51% for infants 750 to 999 g, and by 71% for infants 1000 to 1250 g. The incidence of "prethreshold or greater ROP" decreased by 70% for the 750 to 999 g and 77% for the 1000 to 1250 g weight groups. Although the decrease in "prethreshold or greater ROP" was not as dramatic (25%) for the infants less than 750 g, only 1 infant (10%) progressed to threshold disease in this group, whereas 7 (47%) did in 1986-87. The incidence of threshold ROP decreased by 84% for infants less than 750 g and by 66% for infants 750 to 999 g. No infant with birthweight greater than 999 g progressed to threshold ROP.

CONCLUSIONS

The incidence of all levels of ROP has decreased substantially for all infants with birth weights less than 1251 g at Vanderbilt University Medical Center during the past decade. Putative factors responsible for this decrease may include surfactant use, continuous pulse oximetry, aggressive use of antenatal steroids, and improved neonatal nutritional support.

Impact of an aggressive coronary stenting strategy on the incidence of target lesion revascularization

Coronary stenting has been shown to reduce the incidence of target lesion revascularization (TLR) compared with balloon angioplasty in highly selected patients. However, the impact of an aggressive coronary stenting strategy in unselected patients on the overall incidence of TLR is unclear. We assessed the effect of increased stenting by comparing long-term results in consecutive patients who underwent successful percutaneous revascularization (with or without stents) during June to December 1995 (n=347) with those in June to December 1996 (n=401). Stents were used in 22.5% of patients in 1995 versus 66.1% in 1996 (p <0.0001). Mean age of the patients was 62+/-11 years (71% men) in 1995 versus 63+/-10 in 1996 (76% men) (p=NS). The 2 groups were well matched with the exception that the 1996 cohort included more patients with unstable coronary syndromes (25% in 1995 vs 34% in 1996 (p=0.003). There was no significant difference in the incidence of in-hospital adverse events. After 12 months of follow-up (complete in 95% of patients in each group), the incidence of TLR was significantly lower in the 1996 cohort than in the 1995 cohort (8.5% vs 14.7%, p=0.0075). This was mainly due to reduced requirement for repeat angioplasty in 1996 patients compared with 1995 (6.5% vs 11.8%, p=0.011). It is concluded that in an unselected patient population, an aggressive coronary stenting strategy was associated with a marked overall reduction in requirement for TLR over a 12-month period.

Subatmospheric oxygen therapy complicating subcutaneous emphysema

An infant with hypoplastic left heart syndrome, excessive pulmonary blood flow, and tachypnea was placed on subatmospheric oxygen (supplemental nitrogen) to increase pulmonary vascular resistance and decrease pulmonary blood flow. His cardiorespiratory status stabilized without mechanical ventilation, but 2 weeks later he developed spontaneous subcutaneous emphysema. The emphysema worsened over approximately 1 month. During this time his left-to-right shunt gradually decreased, and he was weaned to room air. Even without the use of supplemental oxygen the emphysema resolved without complication, and the patient underwent successful orthotopic heart transplantation at 65 days of age.

Randomized, multicenter trial of inhaled nitric oxide and high-frequency oscillatory ventilation in severe, persistent pulmonary hypertension of the newborn

BACKGROUND

Although inhaled nitric oxide (iNO) causes selective pulmonary vasodilation and improves oxygenation in newborn infants with persistent pulmonary hypertension, its effects are variable. We hypothesized (1) that the response to iNO therapy is dependent on the primary disease associated with persistent pulmonary hypertension of the newborn (PPHN) and (2) that the combination of high-frequency oscillatory ventilation (HFOV) with iNO would be efficacious in patients for whom either therapy alone had failed.

METHODS

To determine the relative roles of iNO and HFOV in the treatment of severe PPHN, we enrolled 205 neonates in a randomized, multicenter clinical trial. Patients were stratified by predominant disease category: respiratory distress syndrome (n = 70), meconium aspiration syndrome (n = 58), idiopathic PPHN or pulmonary hypoplasia (excluding congenital diaphragmatic hernia) ("other": n = 43), and congenital diaphragmatic hernia (n = 34); they were then randomly assigned to treatment with iNO and conventional ventilation or to HFOV without iNO. Treatment failure (partial pressure of arterial oxygen [PaO2] < 60 mm Hg) resulted in crossover to the alternative treatment; treatment failure after crossover led to combination treatment with HFOV plus iNO. Treatment response with the assigned therapy was defined as sustained PaO2 of 60 mm Hg or greater.

RESULTS

Baseline oxygenation index and PaO2 were 48 +/- 2 and 41 +/- 1 mm Hg, respectively, during treatment with conventional ventilation. Ninety-eight patients were randomly assigned to initial treatment with HFOV, and 107 patients to iNO. Fifty-three patients (26%) recovered with the initially assigned therapy without crossover (30 with iNO [28%] and 23 with HFOV [23%]; p = 0.33). Within this group, survival was 100% and there were no differences in days of mechanical ventilation, air leak, or supplemental oxygen requirement at 28 days. Of patients whose initial treatment failed, crossover treatment with the alternate therapy was successful in 21% and 14% for iNO and HFOV, respectively (p = not significant). Of 125 patients in whom both treatment strategies failed, 32% responded to combination treatment with HFOV plus iNO. Overall, 123 patients (60%) responded to either treatment alone or combination therapy. By disease category, response rates for HFOV plus iNO in the group with respiratory syndrome and the group with meconium aspiration syndrome were better than for HFOV alone or iNO with conventional ventilation (p < 0.05). Marked differences in outcomes were noted among centers (percent death or treatment with extracorporeal membrane oxygenation = 29% to 75%).

CONCLUSIONS

We conclude that treatment with HFOV plus iNO is often more successful than treatment with HFOV or iNO alone in severe PPHN. Differences in responses are partly related to the specific disease associated with PPHN.

Thromboembolic risks of left atrial thrombus detected by transesophageal echocardiogram

Patients with left atrial thrombus are considered at high risk for thromboembolic events. The actual prognosis of these patients and the features most predictive of future events are unclear. We performed transesophageal echocardiograms in 2,894 patients over a 6 1/2-year period; 94 (age 69 +/- 11 years, 59 men, 83 in atrial fibrillation) were found to have left atrial thrombus. The thrombi were considered mobile in 45 patients and 33 patients had thrombus with a maximum dimension > or = 1.5 cm. Seven of the 94 patients with prosthetic valves were excluded from follow-up analysis. Over a follow-up period of 25.3 +/- 19.2 months, 17 patients had suffered a stroke or embolic event (event rate 10.4% per year) and 27 had died (mortality 15.8% per year). Cox proportional hazard regression analysis identified a maximum thrombus dimension > or = 1.5 cm (RR 19, p = 0.002), history of thromboembolism (RR 4.2, p = 0.038), and mobile thrombus (RR 5.3, p = 0.02) as predictors of subsequent thromboembolism. Moderate or severe left ventricular dysfunction was the only significant predictor of death (RR 2.9, p = 0.04). Gender, age, warfarin therapy at follow-up, atrial fibrillation, location (cavity vs appendage) of thrombus, and spontaneous echocardiographic contrast were not significant. Aggressive antithrombotic therapy may be indicated in these high-risk patients.

The natural history of nephrocalcinosis in premature infants treated with loop diuretics

PURPOSE

We investigated the natural history of nephrocalcinosis in premature infants treated with furosemide and attempted to identify factors to predict infants most at risk.

MATERIALS AND METHODS

We evaluated 13 preterm infants in this longitudinal pilot study. During hospitalization and while receiving a loop diuretic nephrocalcinosis developed in each patient. Patients were divided into groups based on resolution (6) and nonresolution (7) according to spontaneous resolution of nephrocalcinosis at any point during followup. The 2 groups were compared to each other and to a control group.

RESULTS

Mean followup after discontinuation of furosemide in the resolution versus nonresolution groups was 10.3 and 7.7 months, respectively. Between the 2 groups there was no significant difference in average gestational age, birth weight, number of days hospitalized or on furosemide, or total furosemide dose. Mean calcium-to-creatinine ratio while receiving furosemide at the time nephrocalcinosis developed was 0.38 in the resolution group but 2.23 in the nonresolution group (p < 0.005). Initial calcium-to-creatinine ratio in age matched infants who did not have nephrocalcinosis was 0.4. Frank renal stones developed in 2 of the 7 patients without resolution and 0 of the 6 with resolution. When nephrocalcinosis resolved, it was at a mean of 5.2 months following discontinuation of the diuretic.

CONCLUSIONS

Early data indicate that nephrocalcinosis resolves in approximately 50% of premature infants 5 to 6 months after discontinuation of furosemide. The only factor that appears to be predictive of the infants who will have resolution is the calcium-to-creatinine ratio when nephrocalcinosis is diagnosed. In patients without resolution this ratio is much higher than in age adjusted normal controls, while in those with resolution it appears normal for age.

Activated clotting time differential is a superior method of monitoring anticoagulation following coronary angioplasty

The standard high-range activated clotting time (sHR ACT) is used to monitor anticoagulation postangioplasty (PTCA), but may be unreliable. We assessed the accuracy of a new method we termed the ACT differential (ACT Diff), obtained by measuring the difference between an sHR ACT and a heparinase ACT from the same sample. Heparinase removes heparin from its sample and provides a current heparin-free baseline. For phase 1 of the study, the sHR ACT, ACT Diff, and laboratory APTT were measured in 250 samples from 75 PTCA patients. In 125 samples with an APTT prolonged but within measurement range, linear regression against the APTT was performed. The correlation coefficient was 0.74 for the ACT Diff and 0.24 for the sHR ACT. An ACT Diff of 15-25 sec was found to equal an APTT of 2.5-3.5 x control. In 50 samples with a normal activated partial thromboplastin time (APT), there was good differentiation by the ACT Diff of results from those adequately heparinized, with a value of 0.9 +/- 4.4 sec. The sHR ACT was 114 +/- 15.5 sec, and could not reliably distinguish between anticoagulated and nonanticoagulated samples. In 75 samples obtained with a high APTT (above measurement range), the ACT Diff was > 30 sec in 95% of samples, and again this allowed differentiation from therapeutic samples. The equivalent sHR ACT was 148 sec, and could not reliably distinguish between anticoagulated and overanticoagulated samples as the ACT Diff could. In phase 2, to examine the clinical usefulness of the ACT Diff, 286 patients were managed post-PTCA by starting heparin when ACT Diff fell to < 50 sec, maintaining ACT Diff at 15-25 sec during heparin infusions, and following cessation of heparin, by removing sheaths when the ACT Diff was < 7 sec. These patients were compared to a control group of 250 patients. Major bleeding (5% vs. 0.5%, P < 0.005) and minor bleeding (30% vs. 13%, P < 0.001) were significantly reduced in the group managed using the ACT Diff. The reduction in bleeding was thought to be due to the rapid availability of reliable results. Abrupt closure was low in both groups (0% with ACT Diff vs. 0.8%). No other thrombotic events occurred. Following phases 1 and 2, the ACT Diff replaced the APTT in all PTCA patients at this institution. In the 18 mo from July 1993, 1,104 patients were managed this way. Incidence of major bleeding (0.2%), transfusion requirement (0.1%), false anneurysm (0.6%), and abrupt closure during heparin infusion (0.1%) remained low. In conclusion, the ACT Diff is more accurate than an sHR ACT, and its clinical use in PTCA patients is associated with a very low incidence of complications from anticoagulation. Its routine use should be considered by units unable to obtain rapid APTT results.

Selection of patients for transesophageal echocardiography after stroke and systemic embolic events. Role of transthoracic echocardiography

BACKGROUND AND PURPOSE

This study examined whether patients suffering from stroke and other systemic embolic events may be selected for transesophageal echocardiography on the basis of clinical and transthoracic echocardiographic findings.

METHODS

We performed transthoracic and transesophageal echocardiography on 824 patients after stroke and other suspected embolic events. Patients were classified into group A if they were in sinus rhythm and had a normal transthoracic echocardiogram. Group B consisted of all other patients. Transesophageal echocardiographic findings of left atrial spontaneous contrast, left atrial thrombus, complex aortic atheroma, and interatrial septal anomalies were correlated with clinical and transthoracic echocardiographic results.

RESULTS

Transesophageal echocardiography detected at least one potential source of embolism in 399 patients (49%): spontaneous contrast in 214 patients (26%), left atrial thrombus in 54 (7%), complex atheroma in 111 (13%), and interatrial septal anomalies in 126 (15%). In group A (n = 236), only 3 (1%) had spontaneous contrast, 11 (4.6%) had complex atheroma, and none had left atrial thrombus. In group B (n = 588), 211 patients (36%, P < .001) had spontaneous contrast, 54 (9.2%, P < .001) had atrial thrombus, and 100 (17%, P < .001) had complex atheroma. Interatrial septal anomalies were detected in similar proportions of patients (18% in group A versus 14% in group B). Left atrial spontaneous echo contrast, thrombus, and complex atheroma were significantly more prevalent in older patients, but interatrial septal anomalies were more prevalent in younger patients irrespective of transthoracic echocardiographic findings. Multivariate analysis identified both an abnormal transthoracic echocardiogram and patient age to be independent predictors of transesophageal echocardiographic findings of left atrial spontaneous echo contrast, left atrial thrombus, or complex atheroma.

CONCLUSIONS

Transesophageal echocardiography has a low yield for left atrial spontaneous contrast, left atrial thrombus, or complex aortic atheroma in patients with normal transthoracic echocardiogram and sinus rhythm and in younger patients. Interatrial septal anomalies are more prevalent in younger patients. Transthoracic echocardiogram should be performed in patients after stroke or systemic embolic events as a noninvasive screening tool. We recommend transesophageal echocardiogram for patients with abnormal transthoracic echocardiogram and in younger patients when the finding of a patent foramen ovale may contribute to patient management.

Commentary on neonatal ECMO: a North American and Scandinavian perspective

Randomized clinical trials have become the cornerstone of clinical decision making in neonatal medicine. The need to establish the safety and efficacy of different treatment regimens by means of an unbiased approach has led to the formation of state-agency supported and voluntary national and international networks. These neonatal networks have greatly facilitated the organization of randomized multicenter trials. Most studies aimed to evaluate specific treatment alternatives for common disorders (e.g. surfactant therapy for RDS and iv gammaglobulins for prevention of nosocomial infections are particularly well suited for a randomized clinical trial). However, appraisal of alternative therapies for rare conditions with excessive mortality and high risk for later sequelae is limited by a number of practical and ethical considerations. In view of the complexity of the problems involved it is hardly surprising that only one recent head-to-head trial of conventional therapy versus ECMO has to our knowledge been published (39). In this investigation 28 full-term infants fulfilling standard ECMO criteria were randomly assigned to be transported for ECMO or to receive conventional treatment available on-site. Fourteen of the 15 infants (93%) referred for ECMO survived compared with 7 of 13 (53%) treated conventionally. The long-term outcome was comparable in both groups. These data support previous reports of significantly better survival following ECMO treatment. However, the notion of > 80% mortality on continuation of conventional therapy in this critically ill population may need to be reassessed. HFO is today part of "conventional" therapy in many centers, surfactant is used routinely and a combination of NO and HFO is being evaluated in several clinical trials (57).(ABSTRACT TRUNCATED AT 250 WORDS)

Resolution of left atrial spontaneous echocardiographic contrast after percutaneous mitral valvuloplasty: implications for thromboembolic risk

Left atrial spontaneous echocardiographic contrast (SEC) is an important marker of increased thromboembolic risk in patients with mitral stenosis. To evaluate the effect of percutaneous transseptal mitral valvuloplasty (PTMV) on SEC, we performed transesophageal echocardiography 1 day before and 3 months after PTMV on 88 consecutive patients. SEC was present in 65 (74%) patients before PTMV and was associated with absence of moderate or severe mitral regurgitation (p = 0.01), a smaller valve area (p = 0.02), an older age (p = 0.04), and atrial fibrillation (p = 0.05). At 3 months, PTMV resulted in a mean absolute and relative increase in valve area of 0.54 +/- 0.36 cm2 and 53% +/- 43%, respectively. SEC resolved in 37 patients but persisted in 28 (32%) patients at the 3-month study. The absolute and relative increase of valve area and worsened mitral regurgitation after PTMV were predictors of resolution of SEC, with the relative increase in valve area being the only significant predictor on multivariate analysis. PTMV frequently results in resolution of SEC, which may have important implications in reducing the thromboembolic risk in these patients.

Modifying fluoroscopic views reduces operator radiation exposure during coronary angioplasty

OBJECTIVES

This three-part study examined the feasibility of reducing operator radiation exposure during coronary angioplasty.

BACKGROUND

As case loads and complexity increase, some cardiologists are receiving increasing radiation scatter doses. Techniques to reduce this are therefore becoming more important.

METHODS

First, the determinants of the operator dose were assessed by measuring the differences in scatter dose with different camera views. The relative contribution of fluoroscopy as opposed to cine was then quantified. Finally, operators were provided with these data, and subsequent changes in technique were evaluated.

RESULTS

Left anterior oblique views resulted in 2.6 to 6.1 times the operator dose of equivalently angled right anterior oblique views. Increasing steepness of the left anterior oblique view also resulted in a progressive increase in operator dose, with left anterior oblique 90 degrees causing eight times the dose of left anterior oblique 30 degrees and three times that of left anterior oblique 60 degrees. In the 45 coronary angioplasty cases prospectively analyzed, fluoroscopy was found to be a greater source of total radiation than cine by a 6.3:1 ratio (range 1.1 to 15.8). Once operators were made aware of the importance of left anterior oblique fluoroscopy, there was a marked reduction in its use. When this was not feasible, there was a reduction in the steepness of the angulation. Left anterior oblique fluoroscopy during angioplasty of the left anterior descending and circumflex coronary arteries was reduced from 40% of total screening time to approximately 5%, and left anterior oblique angulation for fluoroscopy during angioplasty of the right coronary artery decreased from 43.6 degrees (+/- 9.1 degrees) to 29.4 degrees (+/- 2.2 degrees). Success rates (90% vs. 89%) and screening times (19.5 vs. 20.7 min) remained unchanged in 200 coronary angioplasties performed after the study. Average operator radiation dose (measured by radiation badges worn under lead at waist level) was reduced from 32.6 to 14.3 microSv/operator per week despite a slight increase in case load.

CONCLUSIONS

Fluoroscopy is the major source of total radiation exposure during coronary angioplasty, with left anterior oblique views providing the highest dose. Modification of views is feasible and will result in significant reduction of operator radiation dose.

Prognostic implications of left atrial spontaneous echo contrast in nonvalvular atrial fibrillation

OBJECTIVES

This study examined the influence of left atrial spontaneous echo contrast on the subsequent stroke or embolic event rate and on survival in patients with nonvalvular atrial fibrillation.

BACKGROUND

Left atrial spontaneous echo contrast is associated with atrial fibrillation and a history of previous stroke or other embolic events. However, the prognostic implications of spontaneous contrast in patients with nonvalvular atrial fibrillation are unknown.

METHOD

The study group comprised 272 consecutive patients with nonvalvular atrial fibrillation undergoing transesophageal echocardiography. Clinical and echocardiographic data were collected at baseline, and patients were prospectively followed up, and all strokes, other embolic events and deaths were documented. The relation between spontaneous contrast at baseline and subsequent stroke, other embolic events and survival was analyzed.

RESULTS

Left atrial spontaneous echo contrast was detected at baseline in 161 patients (59%). The mean follow-up was 17.5 months. The stroke or other embolic event rate was 12%/year (15 strokes, 3 transient ischemic attacks, 2 peripheral embolisms) in patients with, compared with 3%/year (5 strokes) in patients without, baseline spontaneous contrast (p = 0.002). In 149 patients without previous thromboembolism, the event rate was 9.5%/year in patients with and 2.2%/year in patients without spontaneous contrast (p = 0.003). There were 25 deaths in patients with and 11 deaths in patients without spontaneous contrast. Patients with spontaneous contrast had significantly reduced survival (p = 0.025). On multivariate analysis, spontaneous contrast was the only positive predictor (odds ratio 3.5, p = 0.03) and warfarin therapy on follow-up the only negative predictor (odds ratio 0.23, p = 0.02) of subsequent stroke or other embolic events.

CONCLUSIONS

Transesophageal echocardiography can risk stratify patients with nonvalvular atrial fibrillation by identifying left atrial spontaneous echo contrast. These patients have both a significantly higher risk of developing stroke or other embolic events and a reduced survival, and they may represent a subgroup in whom the risk/benefit ratio of anticoagulation may be most favorable.

Role of transoesophageal echocardiography in the diagnosis and management of aortic root abscess

OBJECTIVE

To assess and compare the roles of transthoracic and transoesophageal echocardiography in the diagnosis and management of an aortic root abscess.

DESIGN

To select patients with echocardiographic diagnosis of aortic valve endocarditis with and without an aortic root abscess and correlate this with a retrospective review of surgical and necropsy data.

SETTING

Tertiary referral centre at a university teaching hospital.

PATIENTS AND METHODS

34 patients with confirmed aortic valve endocarditis were treated over a four and a half year period. All patients underwent both transthoracic and transoesophageal echocardiography with 17 patients having biplane or multiplane imaging.

RESULT

11 patients (32%) had an aortic root abscess. Transthoracic echocardiography identified four cases of aortic root abscess whereas transoesophageal echocardiography correctly detected all 11 cases and also detected complications including mitral aortic intervalvar fibrosa fistula in two patients and right atrial involvement in another two patients. Only biplane imaging was able to show an anterior aortic root abscess in one patient and the circumferential involvement of the aortic annulus in another two patients. All patients with an aortic root abscess were treated surgically after transoesophageal echocardiographic diagnosis. After operation, prosthetic aortic regurgitation was present in seven patients and a repeat operation was performed in three patients. Only transoesophageal echocardiography detected a postoperative aorto-right atrial fistula in two patients and recurrence of the root abscess in another. There were five deaths in hospital (45%).

CONCLUSIONS

Compared with transthoracic echocardiography, transoesophageal echocardiography was more sensitive and more specific for the early diagnosis of aortic root abscess and its complications and facilitated both the preoperative and postoperative management of these patients. Biplane and multiplane imaging provide additional diagnostic information. All patients with suspected aortic valve endocarditis should have an early transoesophageal echocardiographic study.

Exclusion of atrial thrombus by transesophageal echocardiography does not preclude embolism after cardioversion of atrial fibrillation. A multicenter study

BACKGROUND

Transesophageal echocardiography (TEE) has been used recently to detect atrial thrombi before cardioversion of atrial arrhythmias. It has been assumed that embolic events after cardioversion result from embolism of preexisting atrial thrombi that are accurately detected by TEE. This study examined the clinical and echocardiographic findings in patients with embolism after cardioversion of atrial fibrillation despite exclusion of atrial thrombi by TEE.

METHODS AND RESULTS

Clinical and echocardiographic data in 17 patients with embolic events after TEE-guided electrical (n = 16) or pharmacological (n = 1) cardioversion were analyzed. All 17 patients had nonvalvular atrial fibrillation, including four patients with lone atrial fibrillation. TEE before cardioversion showed left atrial spontaneous echo contrast in five patients and did not show atrial thrombus in any patient. Cardioversion resulted in return to sinus rhythm without immediate complication in all patients. Thirteen patients had cerebral embolic events and four patients had peripheral embolism occurring 2 hours to 7 days after cardioversion. None of the patients were therapeutically anticoagulated at the time of embolism. New or increased left atrial spontaneous echo contrast was detected in four of the five patients undergoing repeat TEE after cardioversion including one patient with a new left atrial appendage thrombus.

CONCLUSIONS

Embolism may occur after cardioversion of atrial fibrillation in inadequately anticoagulated patients despite apparent exclusion of preexisting atrial thrombus by TEE. These findings suggest de novo atrial thrombosis after cardioversion or imperfect sensitivity of TEE for atrial thrombi and suggest that screening by TEE does not obviate the requirement for anticoagulant therapy at the time of and after cardioversion. A randomized clinical trial is needed to compare conventional anticoagulant management with a TEE-guided strategy including anticoagulation after cardioversion.

Induction of human neonatal pulmonary fibroblast cytokines by hyperoxia and Ureaplasma urealyticum

Multiple insults may induce bronchopulmonary dysplasia (BPD) in premature infants, including the recently reported association of BPD with neonatal Ureaplasma urealyticum colonization. One mechanism of damage could involve stimulation of proinflammatory cytokine release from pulmonary fibroblasts. We therefore compared the effects of U. urealyticum, oxygen, and lipopolysaccharide (LPS) on the release of interleukin (IL)-1 beta, IL-6, and IL-8 from neonatal fibroblasts. Fibroblasts were grown in multiwell plates and divided into the following experimental conditions: fibroblasts alone, fibroblasts plus U. urealyticum (10,000 cfu/mL), and fibroblasts plus LPS (2 micrograms/mL). Plates were then exposed to room air or hyperoxia for 48 h, and supernatants were assayed for IL. U. urealyticum-infected fibroblasts produced a significant increase in IL-6 (P < .05) and a dramatic increase in IL-8 (P < .05) that was independent of hyperoxic exposure and significantly increased over that produced by LPS or hyperoxia alone. U. urealyticum is a potent inducer of fibroblast cytokine release in vitro and may contribute to the development of BPD.

A primate model of Ureaplasma urealyticum infection in the premature infant with hyaline membrane disease

Cultures positive for Ureaplasma urealyticum in babies weighing < 1000 g have been associated with both chronic lung disease (CLD) and death, but no definite causality has been established. To further investigate the role of the organism in CLD, we colonized premature baboons with U. urealyticum and compared resulting pathology with that in uninoculated control animals. Using an established model of prematurity, the 140-day-gestation baboon, three animals were colonized with U. urealyticum via endotracheal tube. All had hyaline membrane disease, indistinguishable from disease in human infants, and U. urealyticum infection. Samples obtained from nasopharynx, trachea, pleural fluid, and, at necropsy, lung tissue produced positive cultures. Culture of blood from one animal yielded U. urealyticum. On pathologic examination, after 6 days of ventilation, all three of the infected animals had the specific pathologic finding of bronchiolitis with epithelial ulceration not seen in four uninfected control animals. Thus, U. urealyticum is capable of causing a pathologically recognizable pulmonary lesion in premature primates with hyaline membrane disease.

Evaluation of transesophageal echocardiography before cardioversion of atrial fibrillation and flutter in nonanticoagulated patients

This study prospectively evaluated the role of transesophageal echocardiography (TEE) in screening for atrial thrombi before electrical cardioversion in 40 nonanticoagulated patients with nonvalvular atrial fibrillation (n = 33) or atrial flutter (n = 7). Transthoracic echocardiography did not detect atrial thrombus in any patient. TEE detected left atrial appendage thrombi in five patients (12%, p = 0.03), significantly associated with left ventricular systolic dysfunction (p = 0.02) and left atrial spontaneous echo contrast (p = 0.04). Cardioversion was cancelled in the five patients with thrombi and in two patients with spontaneous reversion before planned cardioversion. Cardioversion was successful in 25 (76%) of the 33 remaining patients. Cerebral embolism occurred 24 hours after successful cardioversion in one patient with atrial fibrillation and left ventricular dysfunction, who had left atrial spontaneous echo contrast, but no thrombus was detected by TEE before cardioversion. Repeat TEE after embolism showed a fresh left atrial appendage thrombus and increased left atrial spontaneous echo contrast. These results indicate that TEE improves the detection of left atrial appendage thrombi in candidates for cardioversion, in whom the procedure may be deferred. However, the exclusion by TEE of preexisting atrial thrombi before cardioversion does not eliminate the risk of embolism after cardioversion because of persistent atrial stasis and de novo thrombosis.

Hematologic correlates of left atrial spontaneous echo contrast and thromboembolism in nonvalvular atrial fibrillation

OBJECTIVES

This study examined the relation between left atrial spontaneous echo contrast, hematologic variables and thrombo-embolism in patients with nonvalvular atrial fibrillation.

BACKGROUND

Left atrial spontaneous echo contrast is associated with left atrial stasis and thromboembolism in patients with nonvalvular atrial fibrillation. However, its hematologic determinants in patients with nonvalvular atrial fibrillation are unknown.

METHODS

Clinical, hematologic and echocardiographic variables were prospectively measured in 135 consecutive patients with nonvalvular atrial fibrillation undergoing transesophageal echocardiography.

RESULTS

Patients with left atrial spontaneous echo contrast (n = 74, 55%) had an increased fibrinogen concentration (p = 0.029), platelet count (p = 0.045), hematocrit (p = NS) and left atrial dimension (p = 0.005). Multivariate analysis showed that left atrial spontaneous echo contrast was independently related to hematocrit (odds ratio = 2.24, p = 0.002), fibrinogen concentration (odds ratio = 2.08, p = 0.008) and left atrial dimension (odds ratio = 1.90, p = 0.004) but not platelet count. It was also associated with left atrial thrombus (n = 15, p = 0.001) and with recent embolism (n = 40, p < 0.001). In 40 clinically stable outpatients without previous embolism, left atrial spontaneous echo contrast was significantly related to hematocrit (p = 0.005), fibrinogen concentration (p = 0.035) and left atrial dimension (p = 0.029) but not to coagulation factor VII, D-dimer, erythrocyte sedimentation rate, platelet count, plasma beta-thromboglobulin, plasma glycocalicin or glycocalicin index.

CONCLUSIONS

Left atrial spontaneous echo contrast in patients with nonvalvular atrial fibrillation is independently related to hematocrit, fibrinogen concentration and left atrial dimension, indicating a relatively hypercoagulable state in addition to stasis. These findings support the hypothesis that left atrial spontaneous echo contrast is due to erythrocyte aggregation. Hematologic factors may contribute to its association with thromboembolism.

Transoesophageal echocardiography in heart disease--old technologies, new tricks

Cardiac ultrasound and upper gastrointestinal endoscopy are relatively old technologies. With the introduction of new ultrasound probes and by incorporating ultrasound technology into conventional endoscopes, 'new tricks' in cardiac imaging were discovered. Posterior structures of the heart are now able to be imaged clearly by the ultrasound probe from the oesophagus. Consequently, better resolution of cardiac anatomy allows more accurate diagnosis of cardiac pathologies which is not possible using conventional transthoracic (TT) approach. Over a period of two years, 1200 cases of transoesophageal echocardiography (TOE) were undertaken in our institution. The major indications were diseases of the aorta (10%), source of cardioembolism (28%), assessment of native and prosthetic valve function (20%), suspected endocarditis and its complication (17%), pre and post percutaneous transluminal mitral valvotomy (PTMV [13%], congenital heart disease (2%) and others (10%). The greatest impact with TOE is in the diagnosis of aortic dissection and transection. TOE is superior to conventional TT approach in detecting potential source of embolism, valvular vegetations and its complication, native and prosthetic valve dysfunction and LA thrombus prior to PTMV. Observations by TOE such as spontaneous echo contrast (SEC) in the left atrium open new challenges for further research in its role in the pathogenesis of LA thrombus and its association with cardioembolic event. Other areas of interest include; reclassification of distal aortic dissection and the use of TOE in intra-operative work.

Surfactant lavage in a piglet model of meconium aspiration syndrome

Meconium aspiration continues to be a major cause of morbidity and mortality in newborn infants and is one of the most common indications for extracorporeal membrane oxygenation. Lab studies have suggested that meconium inactivates surfactant and displaces surfactant from the alveolar surface. A recent report has suggested a clinical role for surfactant therapy in human infants with meconium aspiration. We evaluated the effect of surfactant (Survanta) lavage on a piglet model of meconium aspiration. Meconium pneumonitis was created by administration of 4 mL/kg of a 20% slurry of human meconium via endotracheal tube. Twenty-four newborn piglets were then randomly assigned to one of three groups: 1) suction only (n = 7), 2) saline lavage (n = 5), or 3) surfactant lavage (n = 7). Five piglets were excluded from analysis due to death from pneumothorax during meconium administration (n = 3), death from pneumothorax during saline lavage (n = 1), and death from pneumothorax during surfactant lavage (n = 1). The surfactant group had a statistically significant (p less than 0.05) improvement in arterial to alveolar oxygen ratio gradient versus both control groups for the first 3 h. The oxygenation index was statistically significant versus the suction only group at 1, 3, and 4 h. Surfactant lavage of meconium aspiration in piglets results in short-term improvement of oxygenation and warrants further study.

Embolization of a left atrial ball thrombus during transesophageal echocardiography

We report a case of systemic embolization of a left atrial ball thrombus during transesophageal echocardiography (TEE). A 49-year-old man with rheumatic mitral stenosis and atrial fibrillation underwent TEE to evaluate a transient cerebral ischemic attack. TEE demonstrated a free-floating left atrial thrombus. Disappearance of the thrombus during the study occurred after tachycardia and was associated with acute hemiplegic stroke and an absent radial pulse. The possible mechanism of embolization and the implications for the selection and management of patients undergoing TEE are discussed.

Ureaplasma urealyticum demonstrated by open lung biopsy in newborns with chronic lung disease

Lung biopsy tissue from eight infants with chronic lung disease was evaluated for the presence of Ureaplasma urealyticum. Specimens from four infants grew the organism. Pleural fluid cultures matched lung tissue but tracheal cultures were negative in two babies with positive lung tissue. There were no distinguishing pathologic findings in the four culture-positive infants which could be used to identify them vs. the culture-negative infants. Three culture-positive infants improved clinically after therapy directed at Ureaplasma even though two remained culture-positive. Ureaplasma grows in lung tissue of infants with chronic lung disease, it does not demonstrate any specific standard pathologic findings and tissue cultures do not match endotracheal cultures.

Role of transoesophageal echocardiography in evaluation of cardiogenic embolism

OBJECTIVE

To determine the value of transoesophageal echocardiography in the assessment of selected patients at risk of cardiogenic embolism or after it.

DESIGN

Prospective comparison of the results of transoesophageal and transthoracic echocardiography. Transoesophageal echocardiography was performed with a 5 MHz single plane phased array transducer.

SETTING

University teaching hospital.

PATIENTS

100 patients referred for transoesophageal echocardiography after a cerebral ischaemic event or peripheral arterial embolism (n = 63), before percutaneous balloon dilatation of the mitral valve (n = 23), or before electrical cardioversion of atrial fibrillation (n = 14).

RESULTS

Transthoracic echocardiography showed potential sources of embolism in four patients including left ventricular thrombus in two patients (with one false positive), left atrial appendage thrombus (n = 1), and patent foramen ovale (n = 1). Transoesophageal echocardiography showed 59 potential embolic sources in 45 patients including left atrial spontaneous echo contrast (n = 33), left atrial appendage thrombus (n = 13), left ventricular thrombus (n = 5), patent foramen ovale (n = 3), left ventricular spontaneous echo contrast (n = 2), mitral valve prosthesis thrombus (n = 1), mitral valve prolapse (n = 1), and pronounced aortic atheroma (n = 1). Transoesophagal echocardiography showed potential embolic sources in 36/53 (68%) patients with atrial fibrillation compared with 9/47 (19%) patients in sinus rhythm. Percutaneous balloon dilatation of the mitral valve was performed without embolic complications in 18 patients without left atrial thrombi and in three patients with small fixed thrombi in the left atrial appendage. It was cancelled in two patients with large thrombi in the left atrial appendage. Cardioversion was performed without embolic complications in 14 patients without left atrial thrombi.

CONCLUSIONS

Transoesophageal echocardiography detects potential sources of embolism better than transthoracic echocardiography in selected patients at risk of cardiogenic embolism or after it.

Left atrial spontaneous echo contrast: a clinical and echocardiographic analysis

The clinical and echocardiographic variables related to left atrial spontaneous echo contrast were prospectively evaluated in a consecutive series of 400 patients undergoing transesophageal echocardiography with a 5-MHz single plane transducer. Left atrial spontaneous echo contrast was found in 75 patients (19%) and was significantly associated with atrial fibrillation, mitral stenosis, absence of mitral regurgitation, increased left atrial dimension and a history of suspected embolism. Seventy-one (95%) of the patients with spontaneous echo contrast had atrial fibrillation or mitral stenosis. Anticoagulant therapy had no significant association with spontaneous echo contrast. Multivariate analysis in 89 patients with mitral stenosis or mitral valve replacement showed that spontaneous echo contrast was the only independent predictor (p = 0.03) of left atrial thrombus or suspected embolism, or both. In 60 patients with atrial fibrillation of nonvalvular origin, spontaneous echo contrast (p = 0.01) and age (p = 0.03) were the only independent predictors of left atrial thrombus or suspected embolism, or both. It is concluded that left atrial spontaneous echo contrast is 1) a common finding in patients undergoing transesophageal echocardiography, 2) associated with conditions favoring stasis of left atrial blood, and 3) a marker of previous thromboembolism in patients with nonvalvular atrial fibrillation and those with mitral stenosis or mitral valve replacement.

A randomized comparison of intravenous heparin with oral aspirin and dipyridamole 24 hours after recombinant tissue-type plasminogen activator for acute myocardial infarction. National Heart Foundation of Australia Coronary Thrombolysis Group

BACKGROUND

This study addressed the need for heparin administration to be continued for more than 24 hours after coronary thrombolysis with recombinant tissue-type plasminogen activator (rt-PA).

METHODS AND RESULTS

A total of 241 patients with acute myocardial infarction were treated with 100 mg rt-PA and a bolus of 5,000 units i.v. heparin followed by 1,000 units/hr i.v. heparin for 24 hours. At 24 hours, 202 patients were randomized to continue intravenous heparin therapy (n = 99) in full dosage or to discontinue heparin therapy and begin an oral antiplatelet regimen of aspirin (300 mg/day) and dipyridamole (300 mg/day) (n = 103). On prospective recording, there were no differences in the pattern of chest pain, reinfarction, or bleeding complications. Coronary angiography on cardiac catheterization at 7-10 days showed no differences in patency of the infarct-related artery. The proportion of patients with total occlusion (TIMI grade 0-1) of the infarct-related artery was 18.9% in the heparin group and 19.8% in the aspirin and dipyridamole group. In the patients with an incompletely occluded infarct-related artery, the lumen was reduced by 69 +/- 2% of normal in the heparin group and 67 +/- 2% in the aspirin and dipyridamole group. Left ventricular function assessed on cardiac catheterization and radionuclide study at day 2 and at 1 month showed no differences between the two groups. Left ventricular ejection fraction on radionuclide ventriculography at 1 month was 52.4 +/- 1.2% in the heparin group and 51.9 +/- 1.2% in the aspirin and dipyridamole group.

CONCLUSIONS

We conclude that heparin therapy can be discontinued 24 hours after rt-PA therapy and replaced with an oral antiplatelet regimen without any adverse effects on chest pain, reinfarction, coronary patency, or left ventricular function.

The clinical role of transoesophageal echocardiography

The role of transoesophageal echocardiography (TEE) was evaluated in a consecutive series of 100 procedures performed in 86 patients (age 17-81, mean 56 years). All patients had prior transthoracic echocardiography (TTE). TEE was performed with a 5 MHz phased array transoesophageal transducer with pulsed wave Doppler and colour flow mapping capability. Forty-four per cent of patients received intravenous sedation and 36% received antibiotic prophylaxis. There were no complications of TEE. The TTE and TEE findings were compared. In patients referred for possible cardiac source of embolism, left atrial thrombi were detected in 8/27 TEE studies but in none of 27 TTE studies. In 12 patients with prosthetic valve dysfunction TEE distinguished prosthetic from periprosthetic regurgitation in 9/12 studies compared to 3/12 with TTE. In 11 patients with suspected aortic dissection TEE correctly detected dissection in all seven cases in which the diagnosis was subsequently confirmed, whereas TTE showed only equivocal findings in two cases. Vegetations were detected by TEE in 4/5 studies in patients with proven native valve endocarditis and by TTE in 2/5. No vegetations were detected by TTE or TEE in five studies in patients with proven prosthetic valve endocarditis. Compared with other investigations there were no false positive TEE studies and one possible false negative study. We conclude that TEE is a safe procedure which often provides additional clinical information to transthoracic echocardiography.