Extracorporeal membrane oxygenation for infant postcardiotomy support: significance of shunt management

BACKGROUND

After repair of complex congenital heart defects in infants and children, postcardiotomy cardiac failure requiring temporary circulatory support can occur. This is usually accomplished with the use of extracorporeal membrane oxygenation (ECMO). ECMO management of patients with single-ventricle physiology and aorto-pulmonary shunts can be particularly challenging. We retrospectively reviewed our experience with postcardiotomy support with particular attention to those children with single-ventricle palliation.

METHODS

Thirty-five consecutive children (age 1 to 820 days, median 19 days) out of 1,020 patients (3.4%) required mechanical support (ECMO) after repair of congenital cardiac lesions from February 1994 to April 1999. Twenty-five patients underwent two ventricle repairs and 10 patients had single-ventricle palliation. Various parameters analyzed included strategies of shunt management, presence of presupport cardiac arrest, and timing of support initiation.

RESULTS

Overall hospital survival for these 35 patients was 61%. There were four additional late deaths. Hospital survival was the same for those patients in whom support was initiated for failure to wean from cardiopulmonary bypass in the operating room versus those patients in whom support was initiated after successful separation from cardiopulmonary bypass (6 of 10 vs 15 of 25 or 60% survival). In those patients with shunt-dependent pulmonary circulation, survival was significantly improved in those patients in which the aorto-pulmonary shunt was left open (4 of 5 with open shunt vs 0 of 4 with occluded shunt (p = 0.048).

CONCLUSIONS

The ability to readily implement postcardiotomy support is vital to the management of children with complex congenital cardiac disease. Overall survival can be quite satisfactory if support is employed in a rational and expedient manner. In patients with single-ventricle physiology and aorto-pulmonary shunts, leaving the shunt open during the period of support can result in markedly improved outcomes.

Comparison of various hemoglobin polyoxyethylene conjugate solutions as resuscitative fluids after hemorrhagic shock

BACKGROUND

Previous research suggested that splanchnic hypoperfusion occurs after resuscitation with certain acellular hemoglobin solutions. We examined the influence of maltose content and oxygen affinity on resuscitation with various hemoglobin polyoxyethylene conjugate solutions after hemorrhage.

METHODS

Fifteen swine underwent hemorrhage and equal volume resuscitation with pyridoxalated hemoglobin polyoxyethylene conjugate containing 0% or 8% maltose, or low P50 conjugate, which also contained 8% maltose. Five control animals were monitored but not bled. Regional blood flow was determined by using radioactive microspheres, gastric mucosal perfusion was estimated with tonometry, and gut histopathology was evaluated.

RESULTS

All hemoglobin solutions produced vasoconstriction, manifested by elevated mean systemic and pulmonary artery pressures without a significant decrease in cardiac index compared with the sham group. Resuscitation with maltose-containing solutions elevated arterial and regional PCO2 and depressed arterial pH and gastric pHi (p < 0.05 for all). Splanchnic and renal blood flows were reduced in the low P50 + 8% maltose group (p < 0.05 vs. sham and baseline for renal blood flow), possibly indicating greater regional vasoconstriction in this group. Ileal mucosal damage was more severe in the maltose-containing groups and correlated with decreased pHi.

CONCLUSION

Vasoconstriction occurred in all groups but was more severe in the low P50 + 8% maltose group. Maltose-containing solutions caused respiratory acidosis, decreased pHi, and histologic evidence of mucosal injury. Pyridoxalated hemoglobin polyoxyethylene conjugate without maltose was a superior resuscitation solution in this swine model.

Early postoperative changes in regional systolic and diastolic left ventricular function after transmyocardial laser revascularization: a comparison of holmium:YAG and CO2 lasers

OBJECTIVES

The purpose of this study was to determine the short-term effects of transmyocardial laser revascularization (TMR) on regional left ventricular systolic and diastolic function, myocardial blood flow (MBF) and myocardial water content (MWC).

BACKGROUND

Clinical studies of TMR have noted a significant incidence of cardiac complications in the early postoperative period. However, the early post-treatment effects of laser therapy on the myocardium and their potential contribution to postoperative cardiac morbidity are unknown.

METHODS

Swine underwent holmium:yttrium-aluminum-garnet (holmium:YAG) (n = 12) or carbon dioxide (CO2) (n = 12) laser TMR. Regional systolic function for the lased and nonlased regions was quantitated using preload recruitable work area (PRWA) and regional diastolic function with the ventricular stiffness constant alpha.

RESULTS

Preload recruitable work area was significantly decreased in the lased regions both 1 (59.8+/-13.0% of baseline, p = 0.02) and 6 h (64.2+/-9.4% of baseline, p = 0.02) after holmium:YAG TMR. This decreased PRWA was associated with a significant reduction in MBF to the lased regions (13.2% reduction at 1 h, p = 0.02; 18.4% decrease at 6 h post-TMR, p = 0.01). These changes were not seen after CO2 laser TMR. A significant increase in MWC (1.4+/-0.3% increase with holmium:YAG, p = 0.004; 1+/-0.2% increase with CO2, p = 0.002) and alpha (217.4+/-44.2% of baseline 6 h post-holmium:YAG TMR, p = 0.05; 206+/-36.7% of baseline 6 h post-CO2 TMR, p = 0.03) was seen after TMR with both lasers.

CONCLUSIONS

In the early postoperative setting, impaired regional systolic function in association with regional ischemia is seen after TMR with a holmium:YAG laser. Both holmium:YAG and CO2 lasers are associated with increased MWC and impaired diastolic relaxation in the lased regions. These changes may explain the significant incidence of early postoperative cardiac morbidity. The impact of these findings on anginal relief and long-term outcome are not known.

Intracoronary adenovirus-mediated delivery and overexpression of the beta(2)-adrenergic receptor in the heart : prospects for molecular ventricular assistance

BACKGROUND

Genetic modulation of ventricular function may offer a novel therapeutic strategy for patients with congestive heart failure. Myocardial overexpression of beta(2)-adrenergic receptors (beta(2)ARs) has been shown to enhance contractility in transgenic mice and reverse signaling abnormalities found in failing cardiomyocytes in culture. In this study, we sought to determine the feasibility and in vivo consequences of delivering an adenovirus containing the human beta(2)AR cDNA to ventricular myocardium via catheter-mediated subselective intracoronary delivery.

METHODS AND RESULTS

Rabbits underwent percutaneous subselective catheterization of either the left or right coronary artery and infusion of adenoviral vectors containing either a marker transgene (Adeno-betaGal) or the beta(2)AR (Adeno-beta(2)AR). Ventricular function was assessed before catheterization and 3 to 6 days after gene delivery. Both left circumflex- and right coronary artery-mediated delivery of Adeno-beta(2)AR resulted in approximately 10-fold overexpression in a chamber-specific manner. Delivery of Adeno-betaGal did not alter in vivo left ventricular (LV) systolic function, whereas overexpression of beta(2)ARs in the LV improved global LV contractility, as measured by dP/dt(max), at baseline and in response to isoproterenol at both 3 and 6 days after gene delivery.

CONCLUSIONS

Percutaneous adenovirus-mediated intracoronary delivery of a potentially therapeutic transgene is feasible, and acute global LV function can be enhanced by LV-specific overexpression of the beta(2)AR. Thus, genetic modulation to enhance the function of the heart may represent a novel therapeutic strategy for congestive heart failure and can be viewed as molecular ventricular assistance.

Comparison of the Quantiplex version 3.0 assay and a sensitized Amplicor monitor assay for measurement of human immunodeficiency virus type 1 RNA levels in plasma samples

This study evaluated correlation and agreement between version 3 of the Quantiplex human immunodeficiency virus type 1 (HIV-1) RNA assay (v3 branched DNA [bDNA]) and a sensitized Amplicor HIV-1 Monitor assay (reverse transcription [RT]-PCR) for the measurement of HIV RNA. Three hundred eighteen samples from 59 randomly selected, HIV-1-seropositive persons on various drug protocols from the National Institute of Allergy and Infectious Diseases HIV outpatient clinic were studied. The results indicate that v3 bDNA and RT-PCR are highly correlated (r = 0.98) and are in good agreement (mean difference in log(10) copies/ml +/- 2 standard deviations = 0.072 +/- 0.371). The relationship between values obtained by both assays is given by the following equation: log(10)v3 bDNA = -0.0915 + 1. 0052. log(10)RT-PCR. This represents a 1.026-fold difference between log(10)RT-PCR values and log(10)v3 bDNA values.

Orexin A activates locus coeruleus cell firing and increases arousal in the rat

The localization of orexin neuropeptides in the lateral hypothalamus has focused interest on their role in ingestion. The orexigenic neurones in the lateral hypothalamus, however, project widely in the brain, and thus the physiological role of orexins is likely to be complex. Here we describe an investigation of the action of orexin A in modulating the arousal state of rats by using a combination of tissue localization and electrophysiological and behavioral techniques. We show that the brain region receiving the densest innervation from orexinergic nerves is the locus coeruleus, a key modulator of attentional state, where application of orexin A increases cell firing of intrinsic noradrenergic neurones. Orexin A increases arousal and locomotor activity and modulates neuroendocrine function. The data suggest that orexin A plays an important role in orchestrating the sleep-wake cycle.

Enhancement of cardiac function after adenoviral-mediated in vivo intracoronary beta2-adrenergic receptor gene delivery

Exogenous gene delivery to alter the function of the heart is a potential novel therapeutic strategy for treatment of cardiovascular diseases such as heart failure (HF). Before gene therapy approaches to alter cardiac function can be realized, efficient and reproducible in vivo gene techniques must be established to efficiently transfer transgenes globally to the myocardium. We have been testing the hypothesis that genetic manipulation of the myocardial beta-adrenergic receptor (beta-AR) system, which is impaired in HF, can enhance cardiac function. We have delivered adenoviral transgenes, including the human beta2-AR (Adeno-beta2AR), to the myocardium of rabbits using an intracoronary approach. Catheter-mediated Adeno-beta2AR delivery produced diffuse multichamber myocardial expression, peaking 1 week after gene transfer. A total of 5 x 10(11) viral particles of Adeno-beta2AR reproducibly produced 5- to 10-fold beta-AR overexpression in the heart, which, at 7 and 21 days after delivery, resulted in increased in vivo hemodynamic function compared with control rabbits that received an empty adenovirus. Several physiological parameters, including dP/dtmax as a measure of contractility, were significantly enhanced basally and showed increased responsiveness to the beta-agonist isoproterenol. Our results demonstrate that global myocardial in vivo gene delivery is possible and that genetic manipulation of beta-AR density can result in enhanced cardiac performance. Thus, replacement of lost receptors seen in HF may represent novel inotropic therapy.

Molecular beta-adrenergic signaling abnormalities in failing rabbit hearts after infarction

We studied alterations in the beta-adrenergic receptor (beta-AR) system of rabbit hearts during the development of heart failure (HF) after myocardial infarction (MI) to determine whether the molecular beta-AR abnormalities associated with human HF exist in this animal model. Rabbit HF was established 3 wk after left circumflex coronary artery (LCX) ligation by in vivo physiological measurements, and molecular beta-AR signaling was examined in tissue and cultured ventricular myocytes. We found that there was a significant global reduction in beta-AR density by approximately 50% in both ventricles of MI animals compared with sham-operated control animals and that functional beta-AR coupling was significantly reduced. Importantly, as found in human HF, myocardial protein levels and activity of the beta-AR kinase (beta-ARK1) and Galphai were found to be significantly elevated in MI rabbits, suggesting that these molecules are contributing to myocardial dysfunction. Thus the myocardial beta-AR system of this rabbit model of HF shares important biochemical characteristics with human HF and therefore is an ideal laboratory model to investigate novel therapeutic targets for the treatment of HF.

Traumatic aortic rupture: diagnosis and management

BACKGROUND

Traumatic aortic rupture is a relatively uncommon lesion that presents the cardiothoracic surgeon with unique challenges in diagnosis and management. To address controversial aspects of this disease, we reviewed our experience.

METHODS

The study was performed by retrospective chart review.

RESULTS

Forty-two patients with traumatic thoracic aortic ruptures were managed between January 1988 and June 1997. Nine arrived without vital signs and died in the emergency department. Admission chest radiographs were normal in 3 patients (12%) and caused significant delays in diagnosis. Four of 30 patients admitted with vital signs had rupture before thoracotomy and died. Twenty-six underwent aortic repair. In 1 patient repair was performed with simple aortic cross-clamping, whereas a second was managed with a Gott shunt. The remaining 24 patients had repair with partial left heart bypass. In 1 patient hypothermic circulatory arrest was required. Two patients (7.7%) died. There were no cases of new postoperative paraplegia in the bypass group. There was no morbidity directly attributable to the administration of heparin for cardiopulmonary bypass.

CONCLUSIONS

In a discrete group of patients with traumatic rupture of the aorta, the rupture will become complete during the first few hours of hospital admission; aggressive medical treatment with beta-blockade and vasodilators in the interval before the operation is an essential aspect of management. Active distal circulatory support with partial left-heart bypass provides the optimal means of preventing spinal cord ischemia during repair of acute traumatic aortic rupture.

Raloxifene HCl is not stimulatory in the endometrium as assessed by the blaustein criteria and an estrogenicity scoring system

Introduction: Raloxifene, a selective estrogen receptor modulator (SERM), acts as an estrogen agonist in the bone and on serum lipids and an estrogen antagonist in breast tissue. The effect of raloxifene on the endometrium of postmenopausal women is a key factor in determining its clinical application.Objectives: The objectives are to determine and compare the histologic outcomes of endometrial samples from healthy postmenopausal women receiving either a high dose of raloxifene or hormone replacement therapy (HRT).Design: The current study is a 24-month, multicenter, double-blind, randomized study of 136 healthy postmenopausal women randomized to receive either raloxifene 150 mg/day (RLX) or continuous combined HRT (Premarin(R) 0.625 mg/day and Provera(R) 2.5 mg/day).Materials and Methods: Endometrial samples obtained by Pipelle biopsy at baseline and endpoint were evaluated using Blaustein's criteria (Kurman RJ, editor Blaustein's pathology of the female genital tract. 1994), which is composed of descriptive diagnostic categories and a newly developed estrogenicity scoring system to quantify subtle morphologic changes in the postmenopausal endometrium (Boss et al. Am J Obstet Gynecol, in press). All subjects with adequate baseline and post-baseline endometrial samples were included in the analyses. The results from the 12-month interim analyses are reported and the Blaustein's criteria and the estrogenicity scoring system are compared.Results: Overall, 95.2% of the baseline biopsies were normal. At endpoint 30.6% of the subjects in the HRT group with normal baseline biopsies developed proliferative endometrium and 2.8% developed a polyp, while none in the RLX group developed either. Histological evaluation of stromal and glandular features revealed substantially lower estrogenicity scores in the RLX group. As shown in the table, a high degree of agreement was observed between the estrogen effect grades and the Blaustein's descriptive diagnostic categories at endpoint as shown by a Spearman correlation coefficient of 0.75 and a Kappa coefficient of 0.91.Conclusion: Results from the 12-month interim analyses reveal that, in contrast to HRT, raloxifene does not have stimulatory effects on the endometrium. Also, there is high degree of agreement between Blaustein's criteria and the estrogenicity scoring system used to evaluate endometrial histology.

Effect of estrogen and progesterone on newly synthesised and released human fallopian tube specific proteins

Current study was carried out to identify the profile of newly synthesized and released proteins by human fallopian tube (hFT). Results indicated that hFT during menopause synthesised and released only 2-3 proteins as against several proteins ranging from molecular weight (MW) approximately 20 to approximately 130 kD during normal menstrual cycle. In vitro addition of estradiol-17 beta (E2) resulted in synthesis and release of a number of proteins including specific protein of MW 110-130 kD. Addition of progesterone (P) however, led to inhibition of protein synthesis and a combination of E2 and P negated the effect of the latter. An alteration in oviductal secretory protein-profile following addition of E2 in vitro were similar to that observed during normal menstrual cycle.

Effects of raloxifene on serum lipids and coagulation factors in healthy postmenopausal women

CONTEXT

Raloxifene is a selective estrogen receptor modulator that has estrogen-agonistic effects on bone and estrogen-antagonistic effects on breast and uterus.

OBJECTIVE

To identify the effects of raloxifene on markers of cardiovascular risk in postmenopausal women, and to compare them with those induced by hormone replacement therapy (HRT).

DESIGN

Double-blind, randomized, parallel trial.

SETTING

Eight sites in the United States.

PARTICIPANTS

390 healthy postmenopausal women recruited by advertisement.

INTERVENTION

Participants were randomized to receive 1 of 4 treatments: raloxifene, 60 mg/d; raloxifene, 120 mg/d; HRT (conjugated equine estrogen, 0.625 mg/d, and medroxyprogesterone acetate, 2.5 mg/d); or placebo.

MAIN OUTCOME MEASURES

Change and percent change from baseline of lipid levels and coagulation parameters after 3 months and 6 months of treatment.

RESULTS

At the last visit completed, compared with placebo, both dosages of raloxifene significantly lowered low-density lipoprotein cholesterol (LDL-C) by 12% (P < .001), similar to the 14% reduction with HRT (P < .001). Both dosages of raloxifene significantly lowered lipoprotein(a) by 7% to 8% (P < .001), less than the 19% decrease with HRT (P<.001). Raloxifene increased high-density lipoprotein-2 cholesterol (HDL2-C) by 15% to 17% (P < .05), less than the 33% increase with HRT (P < .001). Raloxifene did not significantly change high-density lipoprotein cholesterol (HDL-C), triglycerides, or plasminogen activator inhibitor-1 (PAI-1); whereas HRT increased HDL-C by 11% and triglycerides by 20%, and decreased PAI-1 by 29% (for all, P < .001). Raloxifene significantly lowered fibrinogen by 12% to 14% (P < .001), unlike HRT, which had no effect. Neither treatment changed fibrinopeptide A or prothrombin fragment 1 and 2.

CONCLUSIONS

Raloxifene favorably alters biochemical markers of cardiovascular risk by decreasing LDL-C, fibrinogen, and lipoprotein(a), and by increasing HDL2-C without raising triglycerides. In contrast to HRT, raloxifene had no effect on HDL-C and PAI-1, and a lesser effect on HDL2-C and lipoprotein(a). Further clinical trials are necessary to determine whether these favorable biochemical effects are associated with protection against cardiovascular disease.

Effects of raloxifene on bone mineral density, serum cholesterol concentrations, and uterine endometrium in postmenopausal women

BACKGROUND

Long-term estrogen therapy can reduce the risk of osteoporotic fracture and cardiovascular disease in postmenopausal women. At present, however, these beneficial effects are not separable from undesirable stimulation of breast and endometrial tissues.

METHODS

We studied the effect of raloxifene, a nonsteroidal benzothiophene, on bone mineral density, serum lipid concentrations, and endometrial thickness in 601 postmenopausal women. The women were randomly assigned to receive 30, 60, or 150 mg of raloxifene or placebo daily for 24 months.

RESULTS

The women receiving each dose of raloxifene had significant increases from base-line values in bone mineral density of the lumbar spine, hip, and total body, whereas those receiving placebo had decreases in bone mineral density. For example, at 24 months, the mean (+/-SE) difference in the change in bone mineral density between the women receiving 60 mg of raloxifene per day and those receiving placebo was 2.4+/-0.4 percent for the lumbar spine, 2.4+/-0.4 percent for the total hip, and 2.0+/-0.4 percent for the total body (P<0.001 for all comparisons). Serum concentrations of total cholesterol and low-density lipoprotein cholesterol decreased in all the raloxifene groups, whereas serum concentrations of high-density lipoprotein cholesterol and triglycerides did not change. Endometrial thickness was similar in the raloxifene and placebo groups at all times during the study. The proportion of women receiving raloxifene who reported hot flashes or vaginal bleeding was not different from that of the women receiving placebo.

CONCLUSIONS

Daily therapy with raloxifene increases bone mineral density, lowers serum concentrations of total and low-density lipoprotein cholesterol, and does not stimulate the endometrium.

Course and prognosis in patients > or = 70 years of age with congestive heart failure and normal versus abnormal left ventricular ejection fraction

In this study of 501 patients aged > or =70 years hospitalized with congestive heart failure, 34.1% had normal left ventricular systolic function. Reduced left ventricular ejection fraction was an independent predictor of an adverse prognosis at 3 months but not at 1 year.

The influence of concordant xenografts on the humoral and cell-mediated immune responses to subsequent allografts in primates

The humoral and cell-mediated immune responses to subsequent allografts were determined in primate recipients after concordant xenotransplantation as a bridge to allotransplantation. Heterotopic heart transplants (n = 4) were performed from cynomolgus monkeys into ABH type-matched olive baboons followed 2 weeks later by allotransplantation from ABH type-matched baboon donors. Allografts were explanted at 8 weeks. All recipients underwent splenectomy at the time of xenotransplantation and received immunosuppression with cyclosporine, azathioprine, and methylprednisolone. Concordant xenotransplantation in these primates did not induce humoral or cell-mediated immune responses that jeopardized subsequent allografts. The degree of xenospecific immune reactivity, as determined by specific cytotoxicity of recipient T-cell lines derived from the xenograft and extent of histologic xenograft rejection, did not predict the severity of subsequent allograft rejection. In two of the four recipients, xenotransplantation induced an alloreactive humoral response against antigens expressed by the B cells of more than 50% of members from a panel of 12 unrelated baboons. In all recipients, priming with xenogeneic splenocytes in vitro induced an accelerated proliferative T-cell response to allogeneic lymphocytes from 16% of this panel. This study affirms the role of concordant xenografts as appropriate biologic bridges to human allotransplantation. However, our results suggest that xenoreactive baboon memory CD4 T cells may recognize major histocompatibility complex class II--like structures shared between the xenogeneic and allogeneic targets. The potential allorecognition induced by a xenograft may affect the process of subsequent allograft donor selection.

Iatrogenic congestive heart failure in older adults: clinical course and prognosis

OBJECTIVE

To determine the prevalence, risk factors, clinical course, and prognosis of iatrogenic congestive heart failure in older patients.

DESIGN AND SETTING

Prospective observational study at a university teaching hospital.

PARTICIPANTS

A total of 401 patients 70 years of age or older hospitalized with congestive heart failure. The mean age was 80 +/- 6 years; 59% were female, and 65% were white.

MEASUREMENTS

Comprehensive data, including an assessment of the etiology and precipitating factors leading to the development of heart failure, were collected at the time of diagnosis. Iatrogenic heart failure was defined as heart failure precipitated by medications or excessive fluid administration, or occurring as a procedural complication. All patients were followed for 1 year, and the primary outcome measure was total mortality.

RESULTS

Using strict criteria, 28 patients (7.0%) were considered to have iatrogenic heart failure. Compared with noniatrogenic patients (n = 373), iatrogenic cases had less severe premorbid cardiac disease but more marked noncardiac disability and longer hospital stays (29 +/- 24 vs 13 +/- 12 days, P < .001). Hospital mortality was 32% in iatrogenic heart failure patients compared with 9% in noniatrogenic cases (P < .001). Cumulative mortality at 1 year was 68% in iatrogenic patients versus 39% in noniatrogenic patients (P < .01). Using a Cox proportional hazards model, iatrogenic congestive heart failure was associated with a relative mortality risk during follow-up of 2.5 (95% confidence interval 1.5-4.3) after adjusting for age, sex, prior history of heart failure, New York Heart Association class, diabetes mellitus, systolic blood pressure, hemoglobin, blood urea nitrogen, and serum albumin.

CONCLUSIONS

Frail, debilitated older patients are at increased risk for developing iatrogenic heart failure, even in the absence of clinically evident cardiac disease. In this population, iatrogenic heart failure serves as a marker for poor short- and long-term prognosis, but further study is required to determine the optimal approach to management of these patients.

Miniature axial flow pump for ventricular assistance in children and small adults

We investigated the efficacy of the Jarvik 2000 intraventricular assist device (Jarvik Research, Inc., New York, N.Y.) in an ovine model. The device is an axial flow pump measuring 1.8 cm in diameter by 5 cm long, has a displacement volume of 12 ml, and can deliver flow from 2 to 7 L/min. Seven devices were implanted through a left thoracotomy into the left ventricle with an outflow graft to the descending aorta. Animals were treated with warfarin sodium and aspirin to maintain prothrombin times approximately 1.5 times control. Animals were followed up for 3 to 123 days. Two animals died of operative complications at days 3 and 5. One device failed at 58 days because of thrombus formation at the inflow side of the impeller. The remaining four animals were killed at days 19, 42, 42, and 123, respectively, because of broken electric power cables. Hematocrit values rose significantly higher than preoperative levels (22.8% +/- 3.8% to 30.5% +/- 3.4%); premortem elevations of values higher than baseline values of plasma free hemoglobin (10.4 +/- 7.8 mg/dl to 17.1 +/- 7.4 mg/dl) and lactate dehydrogenase (391.5 +/- 113.7 units/L to 771.2 +/- 370.8 units/L) were statistically insignificant. Serum creatinine and bilirubin levels were normal. No end-organ dysfunction arising from long-term support was evident clinically or at postmortem examination, nor was there any evidence of embolism or damage to intracardiac structures. We found the Jarvik 2000 intraventricular assist device to be easily implantable, safe, nonhemolytic, and able to provide physiologic flow with power requirements under 10 watts.

Newborn baboon immunity: lessons in cross-species transplantation

BACKGROUND

The critical shortage of organ donors has greatly limited the number of heart transplantations performed each year. This is particularly true of the newborn patient, for whom xenotransplantation may provide an alternative therapeutic option to allotransplantation. The role of newborn immunity in xenotransplantation is not clearly understood.

METHODS

We examined the humoral immune responses of 9 nonimmunosuppressed newborn baboons (900 to 1200 g) aged 28 to 44 days undergoing heterotopic pig heart transplantation. Grafts were explanted between 1 and 87 hours after transplantation.

RESULTS

Despite the degree of species, disparity, hyperacute rejection was not observed in any of the nine transplanted grafts. Whole-cell enzyme-linked immunosorbent assay demonstrated newborn baboon serum to contain very low binding levels of anti-pig natural immunoglobulin M xenoantibody when compared with adult baboon serum. Newborn serum, like adult serum, contained anti-pig natural immunoglobulin G xenoantibody. However, newborn baboon serum was not cytotoxic to pig endothelial cells, suggesting that immunoglobulin M and not immunoglobulin G is the primary xenoreactive antibody.

CONCLUSIONS

The low binding levels of anti-pig immunoglobulin M xenoantibody, the absence of cytotoxicity to pig endothelial cells, and the avoidance of hyperacute rejection after heart transplantation suggest that newborn primates may have an immunologic advantage as the recipients of hearts transplanted across species barriers. Whether this advantage can be extended to the human condition is currently being explored in our laboratory.

Nitric oxide treatment for pulmonary hypertension after neonatal cardiac operation

This report describes a newborn with transposition of the great arteries who underwent a Blalock-Taussig shunt with transient improvement in oxygenation, but required emergent insertion of a central shunt later the same day due to progressive hypoxia and cardiac arrest. Two hours after central shunt insertion, sudden episodes of hypoxia and hypotension developed that were resistant to all pharmacologic therapy. Inhaled nitric oxide (25 ppm) was then administered with dramatic improvement in oxygenation and hemodynamics within minutes. The patient's condition stabilized after these measures, and nitric oxide therapy was discontinued after 2 days.

Discriminating between preservation and reperfusion injury in human cardiac allografts using heart weight and left ventricular mass

BACKGROUND

Myocardial edema caused by injury during preservation or reperfusion can affect cardiac function after heart transplantation. This study was designed to distinguish these forms of injury in human allografts.

METHODS AND RESULTS

In 15 donor hearts preserved in University of Wisconsin solution, heart weight (HW) was obtained immediately after explantation and after transport before implantation. Left ventricular mass (LVM) was calculated separately in 18 patients with the use of epicardial two-dimensional echocardiograms obtained both before explantation from the donor and after transplantation and weaning from cardiopulmonary bypass. While changes in LVM could be due to preservation or reperfusion injury, changes in HW can only be due to edema occurring during transport. HW averaged 339 +/- 24 g (mean +/- SE) before and 340 +/- 24 g after transport (P = NS); however, LVM increased 14 g, from 164 +/- 8 to 178 +/- 11 g (P < .05, paired t test). LVM increased in 10 of 18 patients (56%). No correlation was demonstrated between duration of ischemia (mean, 172 +/- 13 minutes) and changes in HW or LVM. Two patients died as a result of primary graft failure. In the first, HW increased 54 g, 2 SD above the mean. In the second, LVM increased 66 g, 2 SD above the mean, but HW changed minimally.

CONCLUSIONS

While current preservation methods result in minimal change in HW during transport, reperfusion injury frequently increases LVM. LVM determination by two-dimensional echocardiography may prove valuable in detecting allograft injury.

Successful heart transplantation with acquired pulmonary artery atresia

Orthotopic cardiac transplantation was performed successfully in a patient with acquired atresia of the left pulmonary artery 19 years after repair of tetralogy of Fallot. Only the right lung could be incorporated into the cardiopulmonary circulation at transplantation, resulting in transient right ventricular dysfunction, which resolved with vasodilator therapy. Perfusion of a single pulmonary vascular bed does not preclude successful heart transplantation, provided there is a low pulmonary vascular resistance and pulmonary artery architecture free of stenoses.

Management strategies for pulmonary vein thrombosis following single lung transplantation

Pulmonary vein thrombosis following lung transplantation is an infrequently reported and often fatal vascular complication. Two cases of early pulmonary vein thrombosis following single lung transplantation are described. Both patients underwent surgical thrombectomy and anastomotic reconstruction following institution of cardiopulmonary bypass, but died of multiorgan failure within 5 days of diagnosis. The efficacy of transesophageal echocardiography as a diagnostic modality, as well as medical and surgical management strategies for thrombectomy, are discussed.

Absence of hyperacute rejection in pig-to-primate orthotopic pulmonary xenografts

The shortage of organ donors for transplantation is more pronounced for the lung than for any other solid organ. To address this problem, we evaluated the feasibility of pulmonary xenotransplantation. Preliminary investigations demonstrated that orthotopically placed pig lungs in cynomologous monkey recipients could be engrafted up to 9 hr after reperfusion without evidence of hyperacute rejection. In this study, the rejection reaction of pig lungs transplanted orthotopically into baboons (n = 6) was further investigated by ELISA and immunohistochemistry. Four baboon recipients were killed at 24 hr and 2 recipients were killed at 72 hr after transplantation. Pulmonary arterial flow measurements demonstrated flow to the grafts, and systemic arterial and xenograft pulmonary venous blood gas analysis suggested function of the donor lungs during the course of engraftment. Serum levels of baboon anti-pig endothelial cell xenoantibody were normal and decreased minimally over time. Immunohistochemical staining of biopsies demonstrated trace IgG and IgM along graft endothelium 2 hr after reperfusion. At 8 hr, biopsy samples showed no immunoglobulin bound to endothelial cells. Staining for complement was negative. Fibrin and platelets were detected along xenograft endothelium. Despite these findings, the lung xenografts appeared injured and clinically rejected. During the first 8 hr after reperfusion, the grafts were hyperemic and subsequently became focally ecchymotic. Chest x-rays showed progressive pulmonary congestion. These findings suggest that the lung may be relatively resistant to antibody-mediated hyperacute rejection and efforts are being directed toward identifying the mechanism of the observed xenograft lung injury.

Development of an intravenous membrane oxygenator: enhanced intravenous gas exchange through convective mixing of blood around hollow fiber membranes

In vitro testing of a new prototype intravenous membrane oxygenator (IMO) is reported. The new IMO design consists of matted hollow fiber membranes arranged around a centrally positioned tripartite balloon. Short gas flow paths and consistent, reproducible fiber geometry after insertion of the device result in an augmented oxygen flux of up to 800% with balloon activation compared with the static mode (balloon off). Operation of the new IMO device with the balloon on versus the balloon off results in a 400% increase in carbon dioxide flux. Gas flow rates of up to 9.5 L/min through the 14-cm-long hollow fibers have been achieved with vacuum pressures of 250 mm Hg. Gas exchange efficiency for intravenous membrane oxygenators can be increased by emphasizing the following design features: short gas flow paths, consistent and reproducible fiber geometry, and most importantly, an active means of enhancing convective mixing of blood around the hollow fiber membranes.

Economic considerations in the use of neuromuscular blocking drugs

The acceptance of new and increasingly expensive technologies is a major component of the rising costs of health care. While the practice of anesthesia has been relatively immune from the effects of cost containment, it is inevitable that practitioners will have to justify costly practices. Available pharmacoeconomic methods can be applied to the use of all anesthetic drugs, particularly neuromuscular blocking drugs. Cost-effectiveness analysis allows the practicing anesthesiologist to prioritize the use of neuromuscular blocking drugs to maximize their benefit while reducing unnecessary costs.

Prevention of readmission in elderly patients with congestive heart failure: results of a prospective, randomized pilot study

OBJECTIVE

To determine the feasibility and potential impact of a non-pharmacologic multidisciplinary intervention for reducing hospital readmissions in elderly patients with congestive heart failure.

DESIGN

Prospective, randomized clinical trial, with 2:1 assignment to the study intervention or usual care.

SETTING

550-bed secondary and tertiary care university teaching hospital.

PATIENTS AND PARTICIPANTS

98 patients > or = 70 years of age (mean 79 +/- 6 years) admitted with documented congestive heart failure.

INTERVENTIONS

Comprehensive multidisciplinary treatment strategy consisting of intensive teaching by a geriatric cardiac nurse, a detailed review of medications by a geriatric cardiologist with specific recommendations designed to improve medication compliance and reduce side effects, early consultation with social services to facilitate discharge planning, dietary teaching by a hospital dietician, and close follow-up after discharge by home care and the study team.

MEASUREMENTS AND MAIN RESULTS

All patients were followed for 90 days after initial hospital discharge. The primary study endpoints were rehospitalization within the 90-day interval and the cumulative number of days hospitalized during follow-up. The 90-day readmission rate was 33.3% (21.7%-44.9%) for the patients receiving the study intervention (n = 63) compared with 45.7% (29.2%-62.2%) for the control patients (n = 35). The mean number of days hospitalized was 4.3 +/- 1.1 (2.1-6.5) for the treated patients vs 5.7 +/- 2.0 (1.8-9.6) for the usual-care patients. In a prospectively defined subgroup of patients at intermediate risk for readmission (n = 61), readmissions were reduced by 42.2% (from 47.6% to 27.5%; p = 0.10), and the average number of hospital days during follow-up decreased from 6.7 +/- 3.2 days to 3.2 +/- 1.2 days (p = NS).

CONCLUSIONS

These pilot data suggest that a comprehensive, multidisciplinary approach to reducing repetitive hospitalizations in elderly patients with congestive heart failure may lead to a reduction in readmissions and hospital days, particularly in patients at moderate risk for early rehospitalization. Further evaluation of this treatment strategy, including an assessment of the cost-effectiveness, is warranted.

Painful, plaque-like, pitted keratolysis occurring in childhood

Pitted keratolysis is a superficial infection of the soles of the feet that is almost always asymptomatic. A painful variant of this disorder was reported to occur in adult males during military service. We report painful, plaque-like, pitted keratolysis in two children. Treatment with topical erythromycin was curative.

Foreign-body granuloma due to an unsuspected wooden thorn

Foreign bodies occasionally cause a chronic granulomatous reaction that may be mistaken for a plantar wart or even a skin malignancy. This possibility should be considered when lesions on the foot become progressively larger and more tender. Diagnosis may require surgical excision.

Three-dimensional ultrasonic reflection and attenuation imaging

A three-dimensional, volumetric, data acquisition and reconstruction system for ultrasonic imaging is described. The method entails storing the digitized waveforms from each element of a multielement annular array, with bidirectional mechanical scanning. The system was implemented through digitization of the RF signals from each of the rings of an annular-array transducer, storage of the signals in computer memory, and offline image reconstruction. Initial reflection and reflex transmission images acquired with this system are presented. The results of different image reconstruction algorithms are demonstrated.

Anatomic fit study for development of a one piece total artificial heart

A fit study was conducted to define anatomic constraints to total artificial heart (TAH) insertion in 26 human orthotopic cardiac transplant recipients, and the parameters necessary for designing a totally implantable TAH were obtained from the excised heart. A multiadjustable fitting device was made (height, 118 mm; width, 81 mm; diameter, 97 mm), and with this model, 15 fitting and measuring studies were conducted to validate the design and demonstrate anatomic compatibility. Satisfactory fit of the contour model was observed in all cases. The model was placed through a sternotomy wound in the pericardial space. In addition to this mock-up fit study, the anatomic dimensions of the connection points to the TAH and the excised hearts also were measured. With the prototype model based on these data, a fit verification study was done in 11 recipients. Satisfactory fit in the pericardial space without compression of adjacent structures was observed in seven of 11 patients. This study suggests that the newly designed model of an anatomically and surgically practical configuration could be implanted in most patients in this population as a completely implantable cardiac prosthesis.

Intraoperative determination of mediastinal constraints for a total artificial heart

The anatomic constraints to mediastinal fit of a total artificial heart (TAH) were largely neglected during the early developmental stages, precipitating failure due to compression or torsion of intrathoracic conduits and vascular structures. Cadaveric studies quantifying anatomic constraints are limited by postmortem factors causing distortion of critical structures. This study defines the anatomic constraints and parameters necessary for designing an implantable TAH. Importantly, these parameters were measured in 12 consecutive patients undergoing orthotopic cardiac transplant (mean body surface area, 2.0 +/- 0.1 m2) after native heart amputation. A full sized contour model of the cylindrical TAH (diameter, 97 mm; width, 78 mm) was inserted into the pericardial cavity to verify fit, which was found adequate in each case, with no identifiable compression of adjacent vascular structures. Intraoperative measurements obtained define intrathoracic and pericardial constraints for a cardiac prosthesis (mean pericardial dimensions: length, 133.0 mm; width, 154.0 mm; depth, 129.0 mm). The parameters measured will provide useful reference for other prosthetic devices, since they were obtained intraoperatively rather than postmortem. The current dimensions of our TAH were found to be acceptable for orthotopic implantation.

Early readmission of elderly patients with congestive heart failure

Repetitive hospitalizations are a major health problem in elderly patients with chronic disease, accounting for up to one fourth of all inpatient Medicare expenditures. Congestive heart failure, one of the most common indications for hospitalization in the elderly, is also associated with a high incidence of early rehospitalization, but variables identifying patients at increased risk and an analysis of potentially remediable factors contributing to readmission have not previously been reported. We prospectively evaluated 161 patients 70 years or older that had been hospitalized with documented congestive heart failure. Hospital mortality was 13% (n = 21). Among patients discharged alive, 66 (47%) were readmitted within 90 days. Recurrent heart failure was the most common cause for readmission, occurring in 38 patients (57%). Other cardiac disorders accounted for five readmissions (8%), and noncardiac illness led to readmission in 21 cases (32%). Factors predictive of an increased probability of readmission included a prior history of heart failure, four or more admissions within the preceding 8 years, and heart failure precipitated by an acute myocardial infarction or uncontrolled hypertension (all P less than .05). Using subjective criteria, 25 first readmissions (38%) were judged possibly preventable, and 10 (15%) were judged probably preventable. Factors contributing to preventable readmissions included noncompliance with medications (15%) or diet (18%), inadequate discharge planning (15%) or follow-up (20%), failed social support system (21%), and failure to seek medical attention promptly when symptoms recurred (20%). Thus, early rehospitalization in elderly patients with congestive heart failure may be preventable in up to 50% of cases, identification of high risk patients is possible shortly after admission, and further study of nonpharmacologic interventions designed to reduce readmission frequency is justified.

Cytochemical and immunophenotypic heterogeneity in acute promyelocytic leukemia

The leukemic promyelocytes in 37 cases of acute promyelocytic leukemia (APML; FAB, M3) were examined for their cytochemical property. Thirty-two cases (86%) showed strong myeloperoxidase (MPO), chloroacetate esterase (Es-chl) and Sudan black B (SBB) positivity, suggesting a pure neutrophilic differentiation of the leukemic cells. However, in 5 out of 37 cases, a strong, diffuse alpha-naphthyl acetate esterase (Es-a) positivity, which was sensitive to sodium fluoride treatment was observed in addition to strong MPO, Es-chl and SBB positivity. This suggested monocytic differentiation of a proportion of APML cases. In 31 cases, surface marker studies were carried out with the help of a panel of monoclonal antibodies consisting of two panmyeloid antibodies (GM 58/8 and 1G10), one anti-HLA-DR antibody (7.2) and one 'myeloid' antibody (5F1) with restricted reactivity with monocytes (CD14). The purpose of including the monoclonal antibodies 5F1 and 7.2 was to determine if a correlation could be established between strong Es-a positivity and reactivity of the leukemic promyelocytes with 5F1 and 7.2 in individual cases. All the 5 cases with 'monocytoid' cytochemistry were unreactive with 5F1, and only one case in this group showed 15% 7.2-positive cells. The lack of immunophenotypic support for the monocytic cytochemistry of the 5 cases of APML suggests that the monocytic phenotype of leukemic promyelocytes is both aberrant and incomplete. Since normal promyelocytes are purely neutrophilic, this could be a manifestation of an 'intralineage infidelity' in APML, similar to that observed in other types of acute leukemia. The clinical significance of 'monocytic' phenotype of APML is not clear; cases with monocytic differentiation did not show different clinical and hematological features when compared to the more common, pure neutrophilic variety.

Experimental studies on mutagenic and carcinogenic effects of tobacco chewing

The alcoholic extract of the chewing (Pandharpuri) variety of tobacco (Nicotiana tabacum) was subjected to mutagenicity and tumorigenicity studies. The extract was found to be mutagenic in strain TA 98 of Salmonella typhimurium in the presence of S 9 mixture. It also induced 8 AZG-resistant mutation in V 79 Chinese hamster cells. Administration of tobacco extract to male Swiss mice by gavage or mixed with diet resulted in an increased incidence of lung/liver tumors. Further, an additive effect of tobacco extract and hexachlorocyclohexane on liver tumor induction was observed.

Epidemiological and experimental studies on tobacco-related oral cancer in India

Both population-based incidence rates and relative frequencies of oral and pharyngeal cancer seen in six major cancer hospitals in India indicate that these forms of cancer occur frequently. Case-control studies reveal that these cancers are associated with tobacco chewing and bidi smoking. Experimental studies on a variety of chewing tobacco used commonly in western India revealed that it contains N-nitrosonornicotine and 4-(methyl-nitrosamino)-1-(3-pyridyl)-1-butanone in microgram quantities per gram of tobacco. A crude alcoholic extract of tobacco containing these nitrosamines was mutagenic in histidine-deficient Salmonella typhimurium strain TA98 in the presence of a 9000 X g supernatant fraction. Gavage feeding of this extract for 7, 15 and 30 days induced activity of mixed-function oxygenases. Feeding of the tobacco extract by gavage or in diets induced lung and liver tumours in Swiss mice.