Effect of managed care on cardiovascular specialists: involvement, attitudes and practice adaptations

OBJECTIVES

This study was undertaken to determine the extent to which cardiovascular specialists are involved with and affected by managed care and to ascertain their attitudes toward it. This survey also served as the follow-up to an initial study on the subject performed by the American College of Cardiology in 1993.

BACKGROUND

The initial 1993 study was performed to address the lack of any comprehensive examination of the impact of managed care on cardiovascular specialists. In 1995, to reexplore this question and follow up the 1993 findings, the College conducted a survey of its membership in the following areas: 1) physician relationship with managed care plans; 2) number of managed care contracts; 3) breakdown of revenue by payment source; 4) changes in practice in response to managed care; and 5) physician attitudes toward managed care. To the extent feasible, the 1995 questionnaire paralleled the 1993 instrument to facilitate comparisons.

METHODS

A questionnaire was mailed to 5,147 practicing College members in the United States, who were categorized by specialty as pediatric cardiologists, adult cardiologists or cardiovascular surgeons. Mailings were sent to 1) all pediatric cardiologists and cardiovascular surgeons; 2) randomly selected adult cardiologists practicing in 10 states with high managed care penetration; and 3) randomly selected adult cardiologists in the nine U.S. census areas who were not practicing in the 10 states with high managed care penetration.

RESULTS

Usable surveys were returned by 1,236 respondents, for an overall response rate of 24%. Involvement with at least one type of managed care organization was reported by 89% of respondents, up from 76% in 1993. Although managed care relationships had increased across physician age, region, practice and specialty, respondents indicated that, on average, well below 50% of their practice revenues stem from managed care contracts. To adapt to the managed care environment, strategic practice changes, such as joining a cardiovascular network, implementing continuous quality improvement systems and adopting clinical pathways, were being instituted by most respondent practices of nine or more physicians. Smaller groups were less active. Most respondents involved with managed care disliked its effects, particularly in clinical matters. Their attitudes toward the assumption of risk, managed fee-for-service arrangements and a private versus single-payer system show that there is no uniformity of opinion regarding the best means to contain costs and promote efficiency.

CONCLUSIONS

Managed care has become an established part of cardiovascular specialist practice in the United States. Although this trend is viewed with some disfavor, most respondents are making practice changes to adapt to this new environment.

Mitochondria-rich cells in the branchial epithelium of the teleost,Oreochromis mossambicus, acclimated to various hypotonic environments

Branchial mitochondria-rich (MR) cells were examined on the afferent side of gill filaments in tilapia (Oreochromis mossambicus) acclimated to different hypotonic environments, local fresh water (LFW), hard fresh water (HFW) and 5‰ salt water (SW). Scanning electron micrographs (SEM) identified three types of apical surfaces of the MR cells, wavy convex, shallow basin and deep hole. In spite of the different types of apical surfaces, light microscopic (LM) and transmission electron microscopic (TEM) studies suggested that these cells were MR cells. The relative abundance of these 3 types of branchial MR cells varied with external hypotonic milieus. Wavy-convexed MR cells were dominant in the gills of fish adapted to HFW, whereas shallow-basined MR cells were evident in LFW-adapted fish. In SW-adapted fish, most of the MR cells were deep holes. Experiments on adaptation to various hypotonic milieus revealed that the changes of the branchial MR cells were reversible and occurred within 24 hours following transfer. The morphological alterations of the MR cells correlated with ionic changes in different milieus, indicating that these distinct types of MR cells may play key roles for osmoregulation in hypotonic media.

Mast cell effector mechanisms

Several lines of evidence support the central role of the cysteinyl leukotrienes in aspirin-sensitive asthma, although their cellular source is unknown. The two most likely cells are the mast cell and eosinophil. Compared with aspirin-tolerant patients with asthma, patients with aspirin-sensitive asthma have been found to have a greater infiltration of mast cells and eosinophils in bronchial biopsy samples, although proportions of activated eosinophils were similar. Findings that support the involvement of mast cells include elevated serum histamine and tryptase levels after aspirin challenge in sensitive subjects, in line with a decrease in lung function and increased histamine and leukotriene C4 levels in nasal secretions; release of high-molecular-weight neutrophil chemotactic factor into serum after challenge; and prevention of aspirin-induced bronchoconstriction by pretreatment with cromolyn sodium or nedocromil sodium. These agents are also effective in protecting against bronchoconstriction induced by hyperosmolar stimuli, a challenge that is not associated with increased leukotriene E4 responsiveness but that is followed by increased release of histamine and prostaglandin D2 into bronchoalveolar lavage fluid. Antihistamines are poorly effective at inhibiting aspirin-induced bronchoconstriction but have been shown to attenuate the bronchoconstrictor response to hyperosmolar challenge. The main effector mechanism in hyperosmolar-induced bronchoconstriction appears to be mast cell activation and histamine release.

Expression of interleukin-1 beta (IL-1beta) and interleukin-1 receptor antagonist (IL-1ra) on asthmatic bronchial epithelium

Accumulating evidence suggests that the cytokine network is central to the immunopathology of bronchial asthma and recent findings have suggested that naturally occurring cytokine antagonists may also be involved. In this study we looked at the expression of interleukin-1 beta (IL-1beta) and its naturally occurring receptor antagonist, IL-1ra, in the normal and asthmatic bronchial wall. Frozen bronchial biopsies from 12 normal and 18 asthmatic individuals were double stained with EBM11 (a CD68 macrophage marker) and either a rabbit anti-IL-1beta or a rabbit anti-IL-1ra. Hue-saturation-intensity color image analysis (HSI) was used to quantify the brown immunoperoxidase reaction product present on the bronchial epithelium. There was an increased expression of both IL-1beta and IL-1ra in the asthmatic bronchial epithelium, p < 0.0002 and p < 0.0001, respectively. Additionally, the numbers of macrophages, of IL-1beta producing cells, and the percentage of macrophages producing IL-1beta were significantly increased in the asthmatic submucosa (p < 0.004, p < 0.002, and p < 0.008, respectively).

Effects of prednisolone on bone turnover in patients with corticosteroid resistant asthma

BACKGROUND

Although corticosteroid resistant (CR) bronchial asthma is associated with impaired in vitro an din vivo glucocorticoid (GC) responsiveness in mononuclear cell function, it is not known whether this is a cell specific phenomenon or whether these patients are at risk of glucocorticoid side-effects as corticosteroid-sensitive (CS) subjects. In order to address this question we have examined the effects of GCs on biochemical indices of bone turnover in vivo.

METHODS

Six CS and six CR subjects received prednisolone 40 mg orally at 09.00 daily for 5 days. At 08.30 on day 1 and day 6 a fasting blood was taken for estimation of serum osteocalcin, tartrate resistant acid phosphatase (TRAP) and alkaline phosphatase (ALP; total and bone isoenzyme), and a urine sample taken for estimation of free deoxy-pyridinoline crosslinks. TRAP and ALP were measured by a colorimetric method and osteocalcin and deoxy-pyridinoline crosslinks by ELISA.

RESULTS

Serum osteocalcin (nmol/L) decreased from 1.39 +/- 0.09 (mean +/- SEM) to 1.14 +/- 0.07 (P = 0.023) and from 1.19 +/- 0.05 to 0.96 +/- 0.1 (P = 0.037) in the CS and CR groups respectively. There was no difference between baseline and post-treatment levels in either group. Serum total ALP (units/L) decreased from 178 +/- 7 to 168 +/- 4 (P = 0.02) and from 195 +/- 22 to 175 +/- 16 (P = 0.04) in the CS and CR groups, respectively. There was no difference between baseline and post-treatment levels in either group. There was no significant elevation of deoxy-pyridinoline crosslinks or TRAP and no suppression of bone ALP in either group.

CONCLUSION

We suggest that CR asthmatics may be equally at risk from the metabolic side-effects of glucocorticoids.

Activation of the HTLV-I long terminal repeat by the hepatitis B virus X protein

The human T-cell leukemia virus type I (HTLV-I) Tax protein and the hepatitis B virus (HBV) X protein have each been shown to activate transcription of their respective viral promoters as well as a subset of cellular gene promoters. Here we show that the HTLV-I long terminal repeat (LTR) is responsive to HBV X transactivation. Maximum levels of X-mediated transactivation of the LTR were 8-fold. An X-responsive-region (XRR) of the LTR is located between nucleotides -355 and -276 and contains an AP-2 binding site, a previously recognized X-responsive element. We demonstrated that Tax and X synergize to activate transcription from the HTLV-I LTR, although the AP-2 binding site was not required for this synergy. These results raise the possibility that the HBV X protein may affect the level of HTLV-I gene expression in co-infected individuals.

Effects of intermittent and continuous cocaine administration on dopamine release and uptake regulation in the striatum: in vitro voltammetric assessment

Chronic daily injections of cocaine induce behavioral sensitization to subsequent cocaine challenge, while continuous infusion induces tolerance. Following a 7-day withdrawal period, we examined the effects of these two dosing regimens on: (1) baseline dopamine efflux and uptake following single-pulse electrical stimulation, (2) inhibition of uptake by cocaine; and (3) inhibition of efflux by autoreceptor activation. Cocaine (40 mg/kg per day) was administered to rats for 14 days either continuously by osmotic minipumps or intermittently by once-a-day injections. Minipumps containing saline were implanted in the control group. After 7 days of withdrawal, dopamine kinetics in the caudate was examined using in vitro fast-scan cyclic voltammetry. This technique provides very rapid measurements of dopamine in the extracellular space. Thus, when combined with endogenous dopamine efflux evoked by single-pulse, electrical stimulations, it was possible directly to measure the release and uptake components of the efflux. In the absence of pharmacological agents, no group differences were found in the amount of baseline dopamine released or in the uptake kinetics; the potency of bath-applied cocaine (0.03-60 microM) in inhibiting the uptake was also unaltered in either group. In contrast, the potency of quinpirole (an autoreceptor agonist, 5-250 nM) was significantly decreased and increased in the cocaine injection and pump groups, respectively. Thus, the cocaine administration regimen which produces sensitization results in a functional subsensitivity of release-modulating autoreceptors, while the tolerance-producing regimen results in autoreceptor supersensitivity.

Combining 'caged-dopamine' photolysis with fast-scan cyclic voltammetry to assess dopamine clearance and release autoinhibition in vitro

We have developed a methodology for inducing a rapid rise in extracellular dopamine concentrations. The clearance of the applied dopamine, as well as its effect on the endogenous dopamine release (i.e., autoinhibition), was then examined using fast scan cyclic voltammetry. In a recording chamber mounted on a Nikon Optiphot epifluorescence microscope, coronal rat brain slices containing either the caudate nucleus or prefrontal cortex were perfused with ACSF containing 100-200 microM 'caged-DA.' UV illumination (100-200 ms) focused at the tip of the recording electrode produced a peak DA concentration of 1-2 microM within 100-200 ms of terminating the illumination. The caudate nucleus exhibited a faster clearance rate for photo-released DA compared to the prefrontal cortex. Cocaine reduced the clearance rates in both the caudate nucleus and prefrontal cortex. In the prefrontal cortex a combination of desipramine/clomipramine also reduced dopamine clearance, suggesting heterologous uptake of the applied DA by noradrenergic and/or serotonergic terminals. Photo-released dopamine inhibited release of endogenous caudate DA release evoked by single electrical stimulation. The advantages of this methodology are discussed.

Cost-effectiveness of a coronary care unit versus an intermediate care unit for emergency department patients with chest pain

BACKGROUND

Guidelines are not available for which patients with acute chest pain should be admitted to the coronary care unit and which patients can be reasonably triaged to monitored beds in lower levels of care.

METHODS AND RESULTS

Clinical and resource utilization data from 12 139 emergency department patients with acute chest pain were used in a decision-analytic model to identify cost-effective guidelines for the admission to a coronary care unit versus an intermediate care unit for initially uncomplicated patients without other indications for intensive care. The probability of clinical complications and death were derived from data on age-specific subsets of the population. Resource utilization estimates were based on cost data from a subset of 901 patients and length of stay data for the entire cohort. The survival benefit associated with initial triage to the coronary care unit instead of an intermediate care unit was assumed to be 15%. In the baseline analysis for 55- to 64-year-old patients, the probability of acute myocardial infarction (AMI) at which the coronary care unit had an incremental cost-effectiveness below $50 000 per year-of-life-saved was 29%. Triage to the coronary care unit was somewhat more cost-effective in elderly patients because their higher early complication rate more than offset their shorter life expectancy.

CONCLUSIONS

This analysis indicates that the coronary care unit usually should be reserved for patients with a moderate (21% or more, depending on the patient's age) probability of AMI unless patients need intensive care for other reasons. Clinical data suggest that only patients with ECG changes of ischemia or infarction not known to be old have a probability of AMI this high. Intermediate care units are appropriate for patients whose risks are not high enough for a coronary care unit to be cost-effective but too high for other alternatives to be recommended for safety and effectiveness.

Increased sensitivity to the hepatocarcinogen diethylnitrosamine in transgenic mice carrying the hepatitis B virus X gene

The role of the hepatitis B virus (HBV) X protein in liver tumorigenesis is unresolved. Transgenic mice harboring the X gene (nt 1376-1840 under the control of the human alpha-1-antitrypsin regulatory elements) (ATX mice) display only minor histopathologic alterations of the liver. To determine if ATX mice are more susceptible to the effects of hepatocarcinogens, 12- to 15-d-old male ATX and control littermate mice were injected with a single dose (2 microgram/g body weight) of diethylnitrosamine (DEN). The animals were killed 6-10 mo after exposure and were analyzed for histological changes in the liver. One hundred percent of the DEN-treated AXT mice developed abnormal liver lesions. Then their liver tissues were compared by stereological analysis with those of non-transgenic animals, the ATX mice had a relative twofold increase in the total number of focal lesion and a twofold increase in the incidence of hepatocellular carcinoma. Elevated levels of X protein and p53 protein were not detected in carcinogen-induced nodules or tumors. These results are consistent with a model in which the expression of the HBV X protein potentiates the induction of DEN-mediated liver disease.

Increased sensitivity to the hepatocarcinogen diethylnitrosamine in transgenic mice carrying the hepatitis B virus X gene

The role of the hepatitis B virus (HBV) X protein in liver tumorigenesis is unresolved. Transgenic mice harboring the X gene (nt 1376-1840 under the control of the human alpha-1-antitrypsin regulatory elements) (ATX mice) display only minor histopathologic alterations of the liver. To determine if ATX mice are more susceptible to the effects of hepatocarcinogens, 12- to 15-d-old male ATX and control littermate mice were injected with a single dose (2 microgram/g body weight) of diethylnitrosamine (DEN). The animals were killed 6-10 mo after exposure and were analyzed for histological changes in the liver. One hundred percent of the DEN-treated AXT mice developed abnormal liver lesions. Then their liver tissues were compared by stereological analysis with those of non-transgenic animals, the ATX mice had a relative twofold increase in the total number of focal lesion and a twofold increase in the incidence of hepatocellular carcinoma. Elevated levels of X protein and p53 protein were not detected in carcinogen-induced nodules or tumors. These results are consistent with a model in which the expression of the HBV X protein potentiates the induction of DEN-mediated liver disease.

Increased sensitivity to the hepatocarcinogen diethylnitrosamine in transgenic mice carrying the hepatitis B virus X gene

The role of the hepatitis B virus (HBV) X protein in liver tumorigenesis is unresolved. Transgenic mice harboring the X gene (nt 1376-1840 under the control of the human alpha-1-antitrypsin regulatory elements) (ATX mice) display only minor histopathologic alterations of the liver. To determine if ATX mice are more susceptible to the effects of hepatocarcinogens, 12- to 15-d-old male ATX and control littermate mice were injected with a single dose (2 microgram/g body weight) of diethylnitrosamine (DEN). The animals were killed 6-10 mo after exposure and were analyzed for histological changes in the liver. One hundred percent of the DEN-treated AXT mice developed abnormal liver lesions. Then their liver tissues were compared by stereological analysis with those of non-transgenic animals, the ATX mice had a relative twofold increase in the total number of focal lesion and a twofold increase in the incidence of hepatocellular carcinoma. Elevated levels of X protein and p53 protein were not detected in carcinogen-induced nodules or tumors. These results are consistent with a model in which the expression of the HBV X protein potentiates the induction of DEN-mediated liver disease.

Factors influencing human immunodeficiency virus type 1 transmission by blood transfusion. Transfusion Safety Study Group

One hundred thirty-two recipients of blood components that retrospectively tested positive for antibody to human immunodeficiency virus type 1 (anti-HIV-1) were identified. Fourteen (11%) remained seronegative throughout follow-up. Donor and recipient characteristics that could have influenced transmission were examined. Attributes did not differ for infected and uninfected recipients. Peripheral blood mononuclear cells (PBMC) from uninfected recipients were HIV-1-negative by DNA amplification and culture but were susceptible to in vitro infection. Transmitting and nontransmitting donors at donation differed only for HIV-1 RNA positivity. By immunocapture reverse transcriptase-polymerase chain reaction, 6 of 11 transmitters and 0 of 11 nontransmitters tested RNA-positive (P = .02). A more sensitive quantitative RNA assay detected RNA in all donation sera, but median levels were higher in transmitting than nontransmitting sera (P = .01). Median CD4 cell counts were lower for transmitting than nontransmitting donors at enrollment (P = .02). Level of viremia is an important determinant of HIV infection by blood transfusion.

Regional anesthesia in foot and ankle surgery

A method of regional anesthesia use in forefoot and midfoot surgery is described. Careful identification of the peripheral sensory nerves allows for effective anesthesia using bupivacaine and lidocaine in addition to sedation for comfort. A review of 355 patients showed that 98% received an effective surgical block of the sensory nerves. Complications were found to be minimal and patient satisfaction was high. This method provides a safe and effective anesthesia alternative for foot and ankle surgery.

Pattern of gp120 sequence divergence linked to a lack of clinical progression in human immunodeficiency virus type 1 infection

Differential rates of AIDS development and/or T4 lymphocyte depletion in HIV-1-infected individuals remain unexplained. The hypothesis that qualitative differences in selection pressure in vivo may account for different rates of disease progression was addressed in nine eligible study participants from a cohort of 315 homosexual men who have been followed since 1985. Disproportionately fewer changes in variable regions and more in C3 of gp12O were found to be significantly associated with slower disease progression. Our finding provides the first example to demonstrate that differential selection pressure related to the emergence of HIV-1 variants is associated with long term nonprogression. Candidate vaccines that elicit strong selection pressure on C3 of gp120 are likely to provide better protection than those targeting variable regions.

Prediction of the need for intensive care in patients who come to emergency departments with acute chest pain

BACKGROUND

Patients who come to the emergency department with chest pain are a heterogeneous group. Some have ischemic heart disease that may lead to serious complications, whereas others have minor disorders. We performed a study to identify clinical factors that predict which patients will have complications requiring intensive care.

METHODS

We first studied 10,682 patients with acute chest pain at seven hospitals between 1984 and 1986 (derivation set) to identify potential clinical predictors of the development of major complications. We then validated these predictors in a separate set of 4676 patients at one hospital between 1990 and 1994 (validation set).

RESULTS

In the derivation set of patients, we identified the following set of clinical features, which, if present in the emergency department, were associated with an increased risk of complications: ST-segment elevation or Q waves on the electrocardiogram thought to indicate acute myocardial infarction, other electrocardiographic changes indicating myocardial ischemia, low systolic blood pressure, pulmonary rales above the bases, or an exacerbation of known ischemic heart disease. On the basis of these criteria, the patients in the validation set were stratified into four groups, with the risk of major complications in the first 12 hours ranging from 0.15 to 8 percent. After 12 hours, the probability of a major complication could be updated on the basis of whether the patient had already had a complication of major severity, a complication of intermediate severity, or a myocardial infarction (independent relative risks, 18.9, 7.7 and 4.0, respectively, as compared with patients without prior complications or myocardial infarction).

CONCLUSIONS

The risk of major complications in patients with acute chest pain can be estimated on the basis of the clinical presentation and new clinical observations made during the hospital course. These estimates of risk help in making rational decisions about the appropriate level of medical care for patients with acute chest pain.

Eosinophil infiltration into human skin is antigen-dependent in the late-phase reaction

Eosinophils play a critical role in late-phase reaction allergic inflammatory responses, although the factors responsible for selective tissue eosinophilia are currently ill-defined. To determine whether recruitment of eosinophils is allergen-specific, or a feature of inflammation in allergic individuals, we have examined cutaneous cell infiltrates and endothelial cell adhesion molecule expression in atopic subjects 6 h (n = 8) and 24 h (n = 7) following ultraviolet-B (UVB) irradiation, or intradermal injection of late-phase reaction allergens or diluent control, using standard immunohistochemical techniques. The numbers of eosinophils were increased significantly, when compared to controls, at both 6 h (P < 0.01) and 24 h (P < 0.05), following intradermal allergen challenge, whereas no significant increase in eosinophils was observed following UVB irradiation. UVB and allergen both induced significant increases in neutrophils, monocytes and T cells at 24 h compared to control sites. An increased expression of endothelial cell adhesion molecules, E-selectin and intercellular adhesion molecule-1 (ICAM-1), was observed in both models of inflammation. Vascular cell adhesion molecule-1 (VCAM-1) was induced weakly on some biopsies following allergen, and not at all following UVB. These data indicate that eosinophil infiltration in susceptible individuals is a specific property of allergen. Although this study would support the postulated role of VCAM-1 in selective eosinophil recruitment, given its variable and weak expression, additional factors are likely to be involved.

Troponin T as a marker for myocardial ischemia in patients undergoing major noncardiac surgery

To assess the diagnostic performance of cardiac troponin T as a marker for myocardial injury in patients undergoing major noncardiac surgery, we prospectively collected preoperative and postoperative clinical data, including measurements for creatine kinase (CK), CK-MB, and troponin T for 1,175 patients undergoing major noncardiac surgery. Acute myocardial infarction was diagnosed in 17 patients (1.4%) by a reviewer who was blinded to troponin T data and who used CK-MB and electrocardiographic criteria to define acute myocardial infarction. Other predischarge major cardiac complications were detected for another 17 patients. Troponin T elevations (>0.1 ng/ml) occurred in 87% of patients with and in 16% of patients without myocardial infarction. Among patients without myocardial infarction, troponin T was elevated in 62% of patients with and in 15% of patients without major cardiac complications. Receiver-operating characteristic analysis indicated that troponin T had a performance for the diagnosis of acute myocardial infarction similar to CK-MB, and a significantly better correlation with other major cardiac complications in patients without definitive infarction. Future research should seek to determine the significance of troponin T elevations in patients without complications.