Real-World Outcomes for the Fifth-Generation Balloon Expandable Transcatheter Heart Valve in the United States

BACKGROUND

The fifth-generation SAPIEN 3 Ultra Resilia valve (S3UR) incorporates several design changes as compared with its predecessors, the SAPIEN 3 (S3) and SAPIEN 3 Ultra (S3U) valves, including bovine leaflets treated with a novel process intended to reduce structural valve deterioration via calcification, as well as a taller external skirt on the 29-mm valve size to reduce paravalvular leak (PVL). The clinical performance of S3UR compared with S3 and S3U in a large patient population has not been previously reported.

OBJECTIVES

The aim of this study was to compare S3UR to S3/S3U for procedural, in-hospital, and 30-day clinical and echocardiographic outcomes after transcatheter aortic valve replacement (TAVR).

METHODS

Patients enrolled in the STS/ACC TVT (Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy) Registry between January 1, 2021, and June 30, 2023, who underwent TAVR with S3UR or S3U/S3 valve platforms were propensity-matched and evaluated for procedural, in-hospital, and 30-day clinical and echocardiographic outcomes.

RESULTS

10,314 S3UR patients were propensity matched with 10,314 patients among 150,539 S3U/S3 patients. At 30 days, there were no statistically significant differences in death, stroke, or bleeding, but a numerically higher hospital readmission rate in the S3UR cohort (8.5% vs 7.7%; P = 0.04). At discharge, S3UR patients exhibited significantly lower mean gradients (9.2 ± 4.6 mm Hg vs 12.0 ± 5.7 mm Hg; P < 0.0001) and larger aortic valve area (2.1 ± 0.7 cm2 vs 1.9 ± 0.6 cm2; P < 0.0001) than patients treated with S3/S3U. The 29-mm valve size exhibited significant reduction in mild PVL (5.3% vs 9.4%; P < 0.0001).

CONCLUSIONS

S3UR TAVR is associated with lower mean gradients and lower rates of PVL than earlier generations of balloon expandable transcatheter heart valve platforms.

Abstract 323: Standardized Triggers for Catheterization Laboratory Morbidity and Mortality Case Review

Background: Guidelines recommend cardiac catheterization laboratories operate a quality improvement program that includes peer review and assesses physician performance. Traditionally this has been accomplished by a morbidity and mortality (M&M) process, but no prior studies have described M&M case selection methods. The use of objective, pre-defined triggers for case selection could avoid under-reporting by physicians and identify complex cases of educational value.

Methods: The Duke University Hospital Cardiac Catheterization Laboratory is a high-volume academic practice that involves trainees in the performance of all coronary angiograms and interventions. At a monthly M&M conference, challenging cases are reviewed to identify opportunities for performance improvement. Cases are selected for review based on the occurrence of pre-defined clinical triggers or by any staff member or physician request. A consensus assessment of physician, staff, and hospital systems performance is reported as a standardized score. We retrospectively reviewed M&M documentation for the purpose of assessing our approach to case selection and performance evaluation.

Results: Of 37,250 coronary catheterizations performed between January 1, 2004 and December 31, 2013, 239 (0.6%) were selected for M&M review based on at least one triggering event. The most common triggering events were defibrillation, unplanned use of mechanical circulatory support, and unplanned intubation (Table). Multiple triggers were present in 118 cases (49.4%). An additional 125 (0.3%) cases were triggered for review by physician or staff request. These included cases resulting in access site hematoma (33 events), peripheral arterial dissection (14), stroke (12), and acute coronary thrombosis (11). “Very controversial” or “unacceptable” performance was identified for physicians in 21 (5.8%) cases, for hospital systems in 3 (1.1%) cases, and in no cases for cath lab staff.

Conclusions: We present a 10-year experience with the use of objective triggers to identify cases for M&M review. This method identifies challenging cases of educational value and could be immediately implemented to strengthen national catheterization laboratory quality improvement programs.

Current status of percutaneous PFO closure

The clinical significance of persistent patent foramen ovale (PFO) is not well defined. Empirically, PFO has been associated with many clinical conditions. In cryptogenic stroke, migraine, and orthodeoxia/platypnea, a plausible biologic mechanism exists to support PFO closure as a possible treatment. Although transcatheter closure of PFO has been available for over 2 decades, it has remained controversial due to a paucity of evidence to guide patient and device selection. Contemporary studies investigating PFO closure as treatment for patients with these conditions have been published recently and longitudinal data regarding the safety and efficacy of the devices is now available. In this review, we aim to describe the potential clinical significance of a patent foramen in the adult, appraise the newest additions to the body of evidence, and discuss the safety, benefit, patient selection, and future of transcatheter treatment of PFO.

Abstract P51: Trends in Utilization of Invasive Cardiac Procedures in North Carolina

Background: Concerns around utilization of coronary revascularization remain in the US. We aimed to understand the temporal trends and variation in invasive diagnostic cardiac catheterization (Cath), percutaneous intervention (PCI) and coronary artery bypass surgery (CABG) in North Carolina from 2003-2009.

Methods: All Cath, PCI, and CABG procedures performed in North Carolina from 2003-2009 were identified using hospital-reported data submitted in a License Renewal Application by all catheterization labs for the North Carolina State Medical Facilities Plan. Rates of procedure use, ratios of PCI to Cath, CABG to Cath, and CABG to PCI were compared over time and between hospitals. Hospitals that performed at least 25 Cath, 25 PCI, and 25 CABG were included in the variation analysis.

Results: From 2003-2009, there was an observed decline in the annual rate of all procedures, 16% for Cath, 9% for PCI, 27% for CABG. However, the ratio of PCI to diagnostic Cath over the time period increased by 10%, rising to 51% in 2009, while the ratio of CABG to Cath decreased by 10% (see Figure). Of the 119 hospitals in North Carolina, 21 hospitals reported performing more than 25 Cath, 25 PCI and 25 CABG each year from 2003-2009. Hospital level analysis also showed evidence of significant variation in the ratio of both PCI to Cath (10% to 90%, p<0.05) and CABG to Cath (5-35%, p<0.05).

Conclusions: Although the use of all cardiac procedures declined, the ratio of PCI to Cath increased over the study period. There was significant variation in the mode of revascularization (CABG and PCI) across hospital systems in North Carolina. Further investigation into revascularization decisions is warranted.

Figure.Trends in Volume and Rates of Diagnostic Cath, PCI, and CABG in North Carolina from 2003-2009.

The ABCD and ABCD2 as predictors of stroke in transient ischemic attack clinic outpatients: a retrospective cohort study over 14 years

BACKGROUND

The ABCD and ABCD2 scores have been validated for use as predictors of stroke in community populations up to 90 days after a transient ischemic attack (TIA). TIA outpatient clinics may see a selective group of patients who have not had an early stroke but may be at raised risk in the medium to long term and therefore benefit from preventive treatment.

AIM

To describe the prognostic values of the ABCD and ABCD2 scores on long-term stroke risk.

DESIGN

Retrospective cohort study of TIA clinic outpatients followed for up to 14 years.

METHODS

Absolute and relative stroke risks, Kaplan-Meier survival curves and cumulative stroke incidence were calculated. Receiver Operating Characteristic curves (ROCs) and areas under the curve were calculated for both scores.

RESULTS

Seven hundred and ninety-five patients were included and 138 (17.3%) experienced a stroke within 13.8 years follow-up after first TIA clinic visit, a crude risk of 26.3 per 1000 person-years. Compared with baseline scores of 0-2, risk ratios for ABCD of 3-4 were 2.95 (95% CI 1.52-6.40), and for 5-6 were 3.42 (95% CI 1.72-7.54); for the ABCD2, risk ratios for 3-4 were 2.68 (95% CI 1.37-5.84), and for 5-7 were 3.55 (95% CI 1.80-7.79). Scores of > or = 3 for either ABCD or ABCD2 predicted raised stroke risks at 90 days, 1, 5 and 10 years. Areas under the curve were 0.619 (95% CI 0.571-0.668) and 0.630 (95% CI 0.582-0.677) for the ABCD and ABCD2 scores, respectively.

CONCLUSION

ABCD and ABCD2 scores of > or = 3 may be clinically useful in identifying TIA outpatients at raised risk of stroke in the medium to long term.

Chemokines and Alzheimer's disease

In recent years, increasing attention has been focused on chemokines as inflammatory mediators in the CNS. The limited number of studies that have investigated chemokine and chemokine receptor expression in Alzheimer's disease (AD) brain and in cell culture models seem to support a role for inflammation in AD pathogenesis. Here we provide a review of these studies, but in addition, point out the possible role of chemokines as communication molecules between neurons and microglia. Understanding neuron-microglia interactions is essential for understanding AD pathogenesis, and disturbances in chemokine-mediated intercellular communication may contribute toward a generalized impairment of microglial cell function.

Comparison of results of percutaneous balloon mitral commissurotomy in patients aged > or = 65 years with those in patients aged < 65 years

Percutaneous balloon mitral commissurotomy (PBMC) is now first-line therapy in patients with symptomatic mitral stenosis (MS) and favorable valve morphology. Unfortunately, the outcome of Medicare-aged patients undergoing this procedure has not previously been defined. The results of PBMC in 55 patients > or = 65 years old (71 +/- 6 years) with moderate or severe MS were compared with 268 younger patients (47 +/- 10). Preprocedural New York Heart Association functional class and pulmonary pressures did not differ. The older patients had higher blood pressure, were more likely to be in atrial fibrillation and had higher valve scores (9.9 +/- 2.5 vs 8.6 +/- 2.2, p = 0.001). Procedural success was higher in the younger group (71% vs 55%, p = 0.013), with a greater increase in mitral valve area. Complications were similar in both groups and there were no periprocedural deaths. At 6 months a significant improvement in function class was seen in both groups. Restenosis, as assessed by serial echocardiography, occurred at a rate of 0.06 cm(2)/year in both groups, and functional class remained unchanged over 3 years. Event-free survival was similar at 48 months: 76% in the younger group and 69% in the older group. Our data thus demonstrates that PBMC can be safely performed in the Medicare-aged population. Despite less acute success in the older population, complication rates do not differ and decrement in valve area over time occurs at a similar rate. Functional class remains improved and event-free survival over 4 years appears similar in both groups. PBMC should thus be offered to patients with MS and suitable anatomy regardless of their age.

Congenital unilateral pulmonary vein atresia: radiologic findings in three adult patients

OBJECTIVE

The purpose of our study is to describe the radiologic findings of adult patients presenting with congenital unilateral pulmonary vein atresia.

CONCLUSION

Chest radiography in affected patients typically reveals a small hemithorax and ipsilateral pulmonary artery as well as ipsilateral septal thickening. CT shows, in addition, ground-glass attenuation, the absence of a pulmonary vein connection to the left atrium, and abundant mediastinal venous collateral vessels. MR imaging is helpful in further characterizing the vascular abnormalities. Angiography may help to confirm the diagnosis.

Mutational analysis of the fractalkine chemokine domain. Basic amino acid residues differentially contribute to CX3CR1 binding, signaling, and cell adhesion

Fractalkine (FKN/CX3CL1) is a unique member of the chemokine gene family and contains a chemokine domain (CD), a mucin-like stalk, a single transmembrane region, and a short intracellular C terminus. This structural distinction affords FKN the property of mediating capture and firm adhesion of FKN receptor (CX3CR1)-expressing cells under physiological flow conditions. Shed forms of FKN also exist, and these promote chemotaxis of CX3CR1-expressing leukocytes. The goal of the present study was to identify specific residues within the FKN-CD critical for FKN-CX3CR1 interactions. Two residues were identified in the FKN-CD, namely Lys-7 and Arg-47, that are important determinants in mediating an FKN-CX3CR1 interaction. FKN-K7A and FKN-R47A mutants exhibited 30-60-fold decreases in affinity for CX3CR1 and failed to arrest efficiently CX3CR1-expressing cells under physiological flow conditions. However, these mutants had differential effects on chemotaxis of CX3CR1-expressing cells. The FKN-K7A mutant acted as an equipotent partial agonist, whereas the FKN-R47A mutant had marked decreased potency and efficacy in measures of chemotactic activity. These data identify specific structural features of the FKN-CD that are important in interactions with CX3CR1 including steady state binding, signaling, and firm adhesion of CX3CR1-expressing cells.

Correlation between quantitative left atrial spontaneous echocardiographic contrast and intact fibrinogen levels in mitral stenosis

An association between left atrial spontaneous echocardiographic contrast (LASEC) and thromboembolic events has been recognized. However, the appearance of LASEC and the assessment of its intensity are gain dependent. To evaluate the relation between LASEC intensity and coagulation activity, 11 patients with mitral stenosis underwent transesophageal echocardiography with quantitative integrated backscatter assessment of LASEC. Right and left atrial blood samples were evaluated for concentrations of coagulation markers, including intact fibrinogen, fibrinopeptide A, D-dimer, prothrombin fragment 1+2, and thrombin-antithrombin III complex. The patients were found to have significantly higher mean left atrial concentrations compared with right atrial concentrations of thrombin-antithrombin III (28.46 +/- 21.05 versus 3.21 +/- 7.16 ng/mL, respectively; P =.001) and fibrinopeptide A (32.78 +/- 17.54 versus 7.42 +/- 8.27 nmol/L, respectively; P <.001). Intact fibrinogen levels were similar in both atria, and a strong, direct correlation existed between left and right atrial intact fibrinogen levels (r = 0.78, P =.005). Quantitative integrated backscatter of LASEC correlated directly with left atrial fibrinogen level (r = 0.78, P =.013) but not with markers of thrombin generation (thrombin-antithrombin III) or activity (fibrinopeptide A). Our results confirm that patients with mitral stenosis have evidence of a regional hypercoagulable state in the left atrium. However, the intensity of LASEC assessed by quantitative integrated backscatter correlates with both right and left atrial intact fibrinogen level, a systemic marker of coagulation.

Aortic dissection after angioplasty and stenting of an aortic coarctation: detection by intravascular ultrasonography but not transesophageal echocardiography

In this case report, an iatrogenic dissection of the descending aorta occurred during balloon angioplasty and stenting of a recurrent coarctation. The dissection was not seen by transesophageal echocardiography, but intravascular ultrasonography, performed routinely during such procedures at this institution, identified the dissection and guided further therapeutic stent placement.

Congenital agenesis of the right pulmonary artery

A 44-year-old woman with recurrent pulmonary infections developed severe hemoptysis. Chest radiography revealed a hypoplastic right lung. Absence of the right pulmonary artery, a very rare congenital anomaly, was demonstrated by computed tomography and cardiac catheterization. Severe pulmonary hypertension in the contralateral lung precluded right pneumonectomy but percutaneous embolization of a large systemic arterial collateral to the right lung provided palliative relief of hemoptysis.

Inhaled nitric oxide selectively dilates pulmonary vasculature in adult patients with pulmonary hypertension, irrespective of etiology

OBJECTIVES

We sought to compare the responses of patients with pulmonary hypertension from primary and secondary causes (PPH and SPH, respectively) to inhaled nitric oxide (iNO) in the cardiac catheterization laboratory.

BACKGROUND

Pulmonary hypertension can lead to right ventricular pressure overload and failure. Although vasodilators are effective as therapy in patients with PPH, less is known about their role in adults with SPH. Inhaled nitric oxide can accurately predict the response to other vasodilators in PPH and could be similarly utilized in SPH.

METHODS

Forty-two patients (26 to 77 years old) with pulmonary hypertension during cardiac catheterization received iNO. Demographic and hemodynamic data were collected. Their response to iNO was defined by a decrease of > or =20% in mean pulmonary artery (PA) pressure or pulmonary vascular resistance (PVR).

RESULTS

Mean PA pressures and PVR were lower during nitric oxide (NO) inhalation in all patients with pulmonary hypertension. Seventy-eight percent of patients with PPH and 83% of patients with SPH were responders to iNO. A trend was seen toward a greater response with larger doses of NO in patients with SPH. Nitric oxide was a more sensitive predictor of response (79%), compared with inhaled oxygen (64%), and was well tolerated, with no evidence of systemic effects. Elevation in right ventricular end-diastolic pressure appeared to predict poor vasodilatory response to iNO.

CONCLUSIONS

Nitric oxide is a safe and effective screening agent for pulmonary vasoreactivity. Regardless of etiology of pulmonary hypertension, pulmonary vasoreactivity is frequently demonstrated with the use of NO. Right ventricular diastolic dysfunction may predict a poor vasodilator response.

Acute excitotoxic injury induces expression of monocyte chemoattractant protein-1 and its receptor, CCR2, in neonatal rat brain

Chemokines are a family of structurally related cytokines that activate and recruit leukocytes into areas of inflammation. The "CC" chemokine, monocyte chemoattractant protein (MCP)-1 may regulate the microglia/monocyte response to acute brain injury. Recent studies have documented increased expression of MCP-1 in diverse acute and chronic experimental brain injury models; in contrast, there is little information regarding expression of the MCP-1 receptor, CCR2, in the brain. In the neonatal rat brain, acute excitotoxic injury elicits a rapid and intense microglial response. To determine if MCP-1 could be a regulator of this response, we evaluated the impact of excitotoxic injury on MCP-1 and CCR2 expression in the neonatal rat brain. We used a reproducible model of focal excitotoxic brain injury elicited by intrahippocampal injection of NMDA (10 nmol) in 7-day-old rats, to examine injury-induced alterations in MCP-1 and CCR2 expression. RT-PCR assays demonstrated rapid stimulation of both MCP-1 and CCR2 mRNA expression. MCP-1 protein content, measured by ELISA in tissue extracts, increased >30-fold in lesioned tissue 8-12 h after lesioning. CCR2 protein was also detectable in tissue extracts. Double-immunofluorescent labeling enabled localization of CCR2 both to activated microglia/monocytes in the corpus callosum adjacent to the lesioned hippocampus and subsequently in microglia/monocytes infiltrating the pyramidal cell layer of the lesioned hippocampus. These results demonstrate that in the neonatal brain, acute excitotoxic injury stimulates expression of both MCP-1 and its receptor, CCR2, and suggests that MCP-1 regulates the microglial/monocyte response to acute brain injury.

Contrast Agents for Cardiac Angiography: Osmolality and Contrast Complications

Radiographic contrast agents have undergone a tremendous evolution over the past several decades. The creation of contrast agents with greater iodine carrying capacity and lower osmolality has improved imaging quality and reduced complications, including nausea, vomiting, congestive heart failure, and cardiac rhythm abnormalities. Whether differences exist among agents in terms of thrombotic complications remains controversial. Several characteristics including potential complications, toxicity, and cost must factor into the decision to use a particular contrast agent in cardiac procedures.

Randomized trial of contrast media utilization in high-risk PTCA: the COURT trial

BACKGROUND

Previous in vitro and in vivo studies have suggested an association between thrombus-related events and type of contrast media. Low osmolar contrast agents appear to improve the safety of diagnostic and coronary artery interventional procedures. However, no data are available on PTCA outcomes with an isosmolar contrast agent.

METHODS AND RESULTS

A multicenter prospective randomized double-blind trial was performed in 856 high-risk patients undergoing coronary artery intervention. The objective was to compare the isosmolar nonionic dimer iodixanol (n=405) with the low osmolar ionic agent ioxaglate (n=410). A composite variable of in-hospital major adverse clinical events (MACE) was the primary end point. A secondary objective was to evaluate major angiographic and procedural events during and after PTCA. The composite in-hospital primary end point was less frequent in those receiving iodixanol compared with those receiving ioxaglate (5.4% versus 9.5%, respectively; P=0.027). Core laboratory defined angiographic success was more frequent in patients receiving iodixanol (92.2% versus 85. 9% for ioxaglate, P=0.004). There was a trend toward lower total clinical events at 30 days in patients randomized to iodixanol (9.1% versus 13.2% for ioxaglate, P=0.07). Multivariate predictors of in-hospital MACE were use of ioxaglate (P=0.01) and treatment of a de novo lesion (P=0.03).

CONCLUSIONS

In this contemporary prospective multicenter trial of PTCA in the setting of acute coronary syndromes, there was a low incidence of in-hospital clinical events for both treatment groups. The cohort receiving the nonionic dimer iodixanol experienced a 45% reduction in in-hospital MACE when compared with the cohort receiving ioxaglate.

Chemokines and their receptors in neurobiology: perspectives in physiology and homeostasis

Chemokines are a large family of small secreted proteins (8-14 kDa) associated with the trafficking of leukocytes in physiological immunosurveillance as well as inflammatory cell recruitment in different disease processes. A limited repertoire of chemokines and their specific cognate receptors are detectable in cells of the CNS such as microglia, astrocytes and neurons under physiological conditions. Coupled with distinct patterns of ligand and receptor expression in various pathologies including multiple sclerosis, trauma, neuro-AIDS, Alzheimer's disease, stroke, neuro- and glioblastomas, such phenomena have fueled the strong belief that chemokines must fulfill significant and potentially diverse functional roles in the CNS.

NF-kappaB-dependent fractalkine induction in rat aortic endothelial cells stimulated by IL-1beta, TNF-alpha, and LPS

Fractalkine is an endothelial cell-derived CX3C chemokine that is chemotactic mainly to mononuclear cells. Fractalkine was induced in rat aortic endothelial cells (RAEC) by interleukin-1beta (IL-1beta), tumor necrosis factor alpha (TNF-alpha), and lipopolysaccharide (LPS) transcriptionally and translationally. This induction correlated with increased NF-kappaB DNA binding activity as determined by gel mobility shift assay. Supershift assays revealed that the NF-kappaB subunits p50 and p65 were responsible for kappaB binding. Accordingly, we examined the role of NF-kappaB in fractalkine induction in RAEC through the use of an adenovirus-mediated mutant IkappaB as a specific inhibitor. Delivery of a dominant-negative form of IkappaBalpha in RAEC dramatically reduced the induction of fractalkine by these stimuli, suggesting a role for NF-kappaB activation in fractalkine induction. The inhibition of fractalkine expression by two potent NF-kappaB inhibitors, sulfasalazine and sanguinarine, further supported the central role of NF-kappaB in fractalkine transcription regulation and suggested a novel therapeutic target aimed at modulating leukocyte endothelial cell interaction.

Percutaneous stenting of right pulmonary artery stenosis in fibrosing mediastinitis

Pulmonary artery stenosis is an uncommon complication of fibrosing mediastinitis. Previous medical and surgical therapies have provided limited clinical efficacy without objective evidence of clinical improvement. With the advantages of limited invasiveness and absent need for prolonged drug therapy, percutaneous stent deployment to relieve pulmonary artery obstruction represents a novel treatment for this rare disorder.

Effect of variability in the interpretation of coronary angiograms on the appropriateness of use of coronary revascularization procedures

BACKGROUND

Evidence from numerous studies of coronary angiography show differences between observers' assessments of 15% to 45%. The implication of this variation is serious: If readings are erroneous, some patients will undergo revascularization procedures unnecessarily and others will be denied an essential treatment. We evaluated the variation in interpretation of angiograms and its potential effect on appropriateness of use of revascularization procedures.

METHODS AND RESULTS

Angiograms of 308 randomly selected patients previously studied for appropriateness of angiography, coronary artery bypass grafting (CABG), and percutaneous transluminal coronary angioplasty (PTCA) were interpreted by a blinded panel of 3 experienced angiographers and compared with the original interpretations. The potential effect on differences on the appropriateness of revascularization was assessed by use of the RAND criteria. Technical deficiencies were found in 52% of cases. Panel readings tended to show less significant disease (none in 16% of vessels previously read as showing significant disease), less severity of stenosis (43% lower, 6% higher), and lower extent of disease (23% less, 6% more). The classification of CABG changed from necessary/appropriate to uncertain/inappropriate for 17% to 33% of cases when individual ratings were replaced by panel readings.

CONCLUSIONS

The general level of technical quality of coronary angiography is unsatisfactory. Variation in the interpretation of angiograms was substantial in all measures and tended to be higher in individual than in panel readings. The effect was to lead to a potential overestimation of appropriateness of use of CABG by 17% and of PTCA by 10%. These findings indicate the need for increased attention to the technical quality of studies and an independent second reading for angiograms before recommending revascularization.

Experimental gliosarcoma induces chemokine receptor expression in rat brain

Macrophage/microglial infiltration is a characteristic feature of brain tumors. The functional role(s) of these cells is complex and could include both trophic and suppressive effects on tumors. Information has recently emerged about the molecular signals that regulate the accumulation and function of monocytes in pathological disorders. Recent data indicate that the chemokine, monocyte chemoattractant protein-1 (MCP-1), a potent monocyte activating and chemotactic factor, is a primary regulator of the macrophage response in brain tumors. We hypothesized that if MCP-1 regulates macrophage/microglial infiltration, then expression of the specific MCP-1 receptor, CCR2, will be induced in peritumoral tissue and/or within brain tumors. Identification of a specific receptor that is preferentially expressed in brain tumors could be important both in terms of tumor biology and as a potential therapeutic target. We used an established experimental gliosarcoma model, induced by intracranial transplantation of cultured 9L cells into adult rat brain, to test this hypothesis. RT-PCR analysis showed high levels of both MCP-1 and CCR2 mRNA and Western blot analysis demonstrated increased CCR2 protein in tumor extracts. Immunocytochemistry showed CCR2 immunoreactive microglia in peritumoral tissue and, unexpectedly, that intrinsic tumor cells, rather than monocytes, were the predominant source of CCR2. These results demonstrate that CCR2 expression is markedly upregulated in this brain tumor model.

Inflammatory agents regulate in vivo expression of fractalkine in endothelial cells of the rat heart

Fractalkine is distinguished structurally from other chemokines in that it contains a mucin-like stalk that tethers a CX3C chemokine module to a transmembrane-spanning region; its expression in cultured endothelial cells has been shown to be up-regulated by tumor necrosis factor alpha (TNF-alpha) and interleukin-1 (IL-1). The purpose of this study was to determine whether fractalkine is expressed, in a proinflammatory agent-regulated manner, by cardiac endothelial cells in vivo. Steady state levels of fractalkine mRNA were increased in rat cardiac tissues after in vivo treatment with lipopolysaccharide (LPS), IL-1, or TNF-alpha. In situ hybridization and immunohistochemical analysis revealed that endothelial cells of the coronary vasculature and endocardium were the principal source of proinflammatory agent-inducible fractalkine, although some fractalkine immunoreactivity was also found on the myocytes. These data are the first demonstration of in vivo cardiac endothelial cell fractalkine expression and regulation by proinflammatory agents such as LPS, IL-1, or TNF-alpha. Cardiac endothelial cell-expressed fractalkine may contribute to the influx of leukocytes into the heart during inflammation.

Assessing the severity of mitral stenosis: variability between noninvasive and invasive measurements in patients with symptomatic mitral valve stenosis

BACKGROUND

This study evaluated the correlation and variability between noninvasive and invasive measures of mitral stenosis severity before and after balloon mitral commissurotomy (BMC) in a large group of patients with symptomatic mitral stenosis. Factors related to variability between measurements were determined.

METHODS

The Doppler transmitral gradient, Doppler half-time valve area, and 2-dimensional echocardiographic (2D) mitral valve area (MVA) were measured immediately before and 1 day after BMC in 272 consecutive patients with mitral stenosis and compared with their respective measures during cardiac catheterization.

RESULTS

The correlation coefficient for the comparison of noninvasive and invasive measurements of the transmitral gradient was 0.63 before BMC and 0.60 after the procedure; for 2D versus Gorlin-derived MVA, 0.39 and 0.57, respectively; and for Doppler half-time versus Gorlin-derived MVA, 0.31 and 0.18, respectively. A large degree of variability in the measurement of MVA was present among the 3 techniques before BMC and increased after BMC. Before BMC, for the comparison of 2D and Gorlin-derived MVA, variables predictive of the discrepancy were age, echocardiographic score, transmitral gradient during catheterization, and cardiac index. For the comparison of Doppler half-time versus Gorlin-derived MVA, age, heart rate during cardiac catheterization and echocardiography, cardiac output and left ventricular end-diastolic pressure predicted the difference between the 2 measures.

CONCLUSIONS

In symptomatic patients with mitral stenosis, there is significant variability between noninvasive and invasive measures of mitral stenosis severity despite careful, reproducible measurements. The difference between noninvasive and invasive measures of MVA before BMC is strongly related to cardiac output.

Mortality and need for reoperation in patients with mild-to-moderate asymptomatic aortic valve disease undergoing coronary artery bypass graft alone

BACKGROUND

Patients presenting for coronary artery bypass graft (CABG) surgery may have concurrent asymptomatic aortic stenosis (AS) or aortic insufficiency (AI). This retrospective study was performed to evaluate outcomes in patients with aortic valve disease undergoing CABG with or without aortic valve replacement (AVR).

METHODS

Study groups included 414 patients undergoing combined AVR and CABG (AVR-CABG group) and 62 patients with asymptomatic mild-to-moderate AS, AI, or both undergoing CABG but not AVR (CABG group). End points included 30-day mortality rate, time to cardiac mortality, time to all-cause mortality, and time to aortic valve reoperation. Reoperation refers to surgery for replacement of the native aortic valve in the CABG group or replacement of the prosthetic aortic valve in the AVR-CABG group. Important patient characteristics affecting outcomes were determined by using Cox proportional-hazard analysis. These variables were then included in multivariable analyses by using logistic regression analysis and Cox proportional-hazard modeling to compare outcomes between each patient group.

RESULTS

No difference was seen in any of the mortality end points between the CABG group and the AVR-CABG group after controlling for significant differences between the groups. However, the need for reoperation for AVR was significantly higher for the CABG group than the AVR-CABG group. For patients followed for up to 6 years, the estimated need for aortic valve reoperation was 24.3% in the CABG group versus 3% in the AVR-CABG group.

CONCLUSION

On the basis of these results, patients with asymptomatic AS or AI should be considered for AVR at the time of CABG.

Cultured rat microglia express functional beta-chemokine receptors

We have investigated the functional expression of the beta-chemokine receptors CCR1 to 5 in cultured rat microglia. RT-PCR analysis revealed constitutive expression of CCR1, CCR2 and CCR5 mRNA. The beta-chemokines MCP-1 (1-30 nM) as well as RANTES and MIP-1alpha (100-1000 nM) evoked calcium transients in control and LPS-treated microglia. Whereas, the response to MCP-1 was dependent on extracellular calcium the response to RANTES was not. The effect of MCP-1 but not that of RANTES was inhibited by the calcium-induced calcium release inhibitor ryanodine. Calcium responses to MCP-1- and RANTES were observed in distinct populations of microglia.

Prevention of crescentic glomerulonephritis by immunoneutralization of the fractalkine receptor CX3CR1 rapid communication

BACKGROUND

Fractalkine is a newly identified T-cell and monocyte/macrophage (Mphi) chemokine with a transmembrane domain and is a cell-surface protein on activated endothelium. It can mediate adhesion of cells expressing the fractalkine receptor CX3CR1. These unique features make fractalkine well suited for leukocyte recruitment in tissues with high blood flow as in the renal glomerulus.

METHODS

Fractalkine expression in glomeruli and response of isolated glomerular inflammatory cells to fractalkine were studied in the Wistar-Kyoto (WKY) crescentic glomerulonephritis model. Antibody was used to confirm the proinflammatory role of fractalkine.

RESULTS

Fractalkine was markedly induced in the endothelium of nephritic rat glomeruli, and inflammatory leukocytes infiltrating the glomeruli expressed increased levels of CX3CR1. Anti-CX3CR1 antibody treatment dramatically blocked leukocyte infiltration in the glomeruli, prevented crescent formation, and improved renal function.

CONCLUSIONS

Fractalkine plays a central role in leukocyte trafficking at the endothelium in the high-flow glomerular circuit and, in turn, implicates CX3CR1 as a prime drug target for therapeutic intervention of endothelium-related inflammatory diseases.

Influence of managed care on professional nursing practice

PURPOSE

To explore how nurses in one U.S. state perceived that managed care influenced professional nursing in that state. The nursing community is challenged to move with haste in demonstrating, through research, the clinical and economic value that nurses add to cost-effective outcomes.

DESIGN

A Delphi survey in 1996 of a convenience sample of 84 clinical nurse specialists (CNSs) and nurse practitioners (NPs) in California.

METHODS

CNSs and NPs contributed to the list of managed care influences on nursing practice. fifty-seven (68%) completed the third and final round.

FINDINGS

Panelist agreement was the highest for (a) exploring new approaches to providing quality care more cost-effectively, (b) expanding nurse practitioners' role in primary care, and (c) more effectively partnering with clients in helping them assume greater self-responsibility for their health. Greatest threats were perceived to be hassles involved in seeking authorization for care and responding to payment denials; the tenuous job market for nurses; and encroachment on nursing practice by others.

CONCLUSIONS

The findings can assist nurses in states with low managed-care concentration to create their preferred future within health care delivery. A more highly educated nurse workforce will be needed for 21st century health systems in which more care is likely to be delivered outside hospitals.

Hypoxemia after prior cardiac surgery due to interatrial shunting and its treatment with a novel transcatheter occlusion device

We describe two unusual cases of hypoxemia after cardiac surgery due to intracardiac right-to-left shunting through a patent foramen ovale or atrial septal defect. The interatrial defects were successfully occluded by placement of a novel, transcather device, the Angelwings Atrial Septal Defect Occluder Device, with resolution of hypoxemia.

Structure-affinity profile of 8-hydroxycarbostyril-based agonists that dissociate slowly from the beta2-adrenoceptor

Several carbostyril-based beta-agonists have been shown to bind tightly to and slowly dissociate from the beta2-adrenoceptor (beta2AR). In the present study, the structural features of 8-hydroxy-5-[2-[(1-phenyl-2-methylprop-2-yl)amino]-1-hydroxyethyl] -carbostyril (11a) which contribute to its binding properties at the beta2AR were investigated using a series of synthesized analogs. The k(off), estimated by the rate of cAMP decline in DDT1 MF-2 (DDT) cells with a reduced receptor density, Ki and ligand-induced receptor reductions were determined. All of the derivatives stimulated cAMP accumulation in DDT cells in the sub to mid nanomolar range and elicited the same maximal stimulation as (-)isoproterenol. Derivatives of 11a with side chain N-substitutions comprising 2-methylbutyl, phenylethyl and isopropyl had higher k(off)-values and lower affinities as compared to 11a. Increasing the number of methylenes between the side chain tertiary alpha carbon and phenyl from 1 in 11a to 3 or reducing the number to 0 also resulted in derivatives with higher k(off)- and Ki-values. In addition, replacement of the 8-hydroxycarbostyril nucleus of 11a with catechol reduced the affinity of the compound for the beta2AR by 48-fold and increased its k(off). Only those derivatives with the lowest k(off)-values induced a decrease in the receptor density of DDT cell membranes following a preincubation and extensive washing. The data show that the 8-hydroxycarbostyril nucleus in conjunction with substitutions on the tertiary alpha carbon of the side chain and positioning of the phenyl group are important characteristics determining the high affinity and slow dissociation of 11a from the beta2AR.

Predictors and significance of atrial rhythm before and six months after percutaneous balloon mitral commissurotomy

Clinical, echocardiographic, and cardiac catheterization data were evaluated in 263 patients with mitral stenosis who were undergoing balloon commissurotomy to determine the predictors of atrial rhythm and its effect on functional status. Conversion from atrial fibrillation to sinus rhythm at 6 months after the procedure occurred in 16 of 86 patients (19%) and was predicted by the duration of atrial fibrillation, baseline functional class, and antiarrhythmic therapy; patients who remained in atrial fibrillation had a poorer functional status compared with those in sinus rhythm despite similar procedural results.

Determinants of 15-year outcome with 1,119 standard Carpentier-Edwards porcine valves

BACKGROUND

The determinants of long-term outcome 15 years or more after porcine valve replacement are poorly documented.

METHODS

A retrospective review was performed of patients undergoing valve replacement with standard Carpentier-Edwards aortic (n = 531), mitral (n = 492), and tricuspid (n = 96) valves.

RESULTS

Patient survival was 26%+/-3%, 23%+/-2%, and 31%+/-8% 15 years after aortic, mitral, and tricuspid valve replacements, respectively. Independent determinants of impaired long-term survival for aortic or mitral valve replacement were multiple valve replacement, older age, renal disease, lung disease, or coronary disease. Actual (versus actuarial) freedom from reoperation at 15 years was 86%+/-2%, 76%+/-2%, and 95%+/-2% after aortic, mitral, and tricuspid valve replacement, respectively. Risk factors for reoperation were young age for aortic or mitral valve replacement, previous operation for aortic valve replacement, and large valve size for mitral valve replacement. Freedom from thromboembolism was 77%+/-4%, 62%+/-9%, and 80%+/-5%; from hemorrhage, 95%+/-5%, 87%+/-4%, and 82%+/-6%; and from endocarditis, 94%+/-1%, 96%+/-1%, and 89%+/-5% 15 years after aortic, mitral, and tricuspid valve replacement, respectively. Risk factors for thromboembolism or hemorrhage were multiple valve replacement and age.

CONCLUSIONS

The standard Carpentier-Edwards bioprosthesis continues to provide relatively low complication rates at 15 years, especially in the aortic and tricuspid positions, and especially in patients older than 60 years or with significant comorbdity.

What does the left atrial v wave signify during balloon commissurotomy of mitral stenosis?

Left atrial v-wave amplitude has been associated with the presence and severity of chronic mitral regurgitation (MR) but it has not been evaluated for the detection of acute MR. We evaluated the left atrial v-wave amplitude of 205 consecutive patients with mitral stenosis immediately before and after stepwise, incremental balloon mitral commissurotomy to determine predictors of large v waves at baseline and an increase in v-wave amplitude after balloon commissurotomy. The sensitivity and specificity of an increase in v-wave amplitude for detecting worsening and severe MR were determined. A large v wave was present in 44% of patients before balloon commissurotomy and was predicted by age, mean left atrial pressure, mean transmitral gradient, mean pulmonary artery pressure, and angiographic severity of MR. There was a strong inverse correlation between v-wave amplitude and calculated left atrial compliance (r = -0.92). An increase in v-wave amplitude after balloon commissurotomy was associated with an increasing probability of worsening or severe MR. This indicator had a sensitivity, specificity, and positive and negative predictive values of 35%, 91%, 64%, 75%, respectively, for detecting any increase in MR. For the detection of severe MR, the sensitivity was 79%, specificity 89%, positive predictive value 42%, and negative predictive value 98%. Thus, left atrial v-wave amplitude reflects left atrial compliance and severity of mitral stenosis before balloon commissurotomy. An increase in v-wave amplitude is an insensitive but very specific indicator of worsening or severe MR during stepwise, incremental balloon mitral commissurotomy.

Comparison of open mitral commissurotomy with mitral valve replacement with or without chordal preservation in patients with mitral stenosis

BACKGROUND

Percutaneous balloon mitral valvuloplasty and durable mitral prostheses have made the role of open mitral commissurotomy (OMC) uncertain.

METHODS AND RESULTS

Results from the use of St Jude mitral valve replacement (SJMVR) were compared with those of the use of OMC in 312 consecutive patients with mitral stenosis between 1983 and the present. OMC and SJMVR patients were well matched for age, sex, and comorbidity except that SJMVR patients had more severe stenosis and were more likely to undergo concurrent aortic valve replacement. Compared with OMC, SJMVR without chordal preservation involved a longer pump time (158 +/- 81 versus 87 +/- 41 min, P < 0.05), more frequent in-hospital complications or death (57 of 219 [26%] versus 4 of 52 [8%], P < 0.01), and longer hospital stay (13 +/- 11 versus 10 +/- 6 days, P = 0.001). Preservation of chordae to at least 1 mitral valve leaflet decreased early morbidity and mortality rates of SJMVR to values comparable to those of OMC (3 of 41 [7%]). Survival was greater at 10 years for OMC versus SJMVR (86 +/- 5% versus 67 +/- 4%, P = 0.03). Ten-year freedom from cardiac events was not different between groups (49 +/- 9% for OMC versus 55 +/- 4% for SJMVR, P = 0.7). Freedom from subsequent mitral procedures at 10 years was better for SJMVR (96 +/- 2% versus 58 +/- 8%, P < 0.001).

CONCLUSIONS

In the modern era, SJMVR offers significantly greater durability than does OMC. Chordal preservation at the time of SJMVR may reduce perioperative complications to levels comparable to those of OMC.

Excitotoxic brain injury stimulates expression of the chemokine receptor CCR5 in neonatal rats

Chemokines interact with specific G-protein-coupled receptors to activate and direct recruitment of immune cells. Some chemokines are up-regulated in pathological conditions of the central nervous system, and recently several chemokine receptors, including CCR5, were identified in the brain. However, little is known about the regulation of expression of chemokine receptors in the brain. Direct intracerebral injection of N-methyl-D-aspartate (NMDA), an excitatory amino acid agonist, elicits reproducible focal excitotoxic brain injury; in neonatal rats, intrahippocampal NMDA injection stimulates expression of pro-inflammatory cytokines and elicits a robust microglia/monocyte response. We hypothesized that NMDA-induced neurotoxicity would also stimulate expression of CCR5 in the neonatal rat brain. We evaluated the impact of intrahippocampal injections of NMDA on CCR5 expression in postnatal day 7 rats. Reverse transcription polymerase chain reaction revealed an increase in hippocampal CCR5 mRNA expression 24 hours after lesioning, and in situ hybridization analysis demonstrated that CCR5 mRNA was expressed in the lesioned hippocampus and adjacent regions. Western blot analysis demonstrated increased CCR5 protein in hippocampal tissue extracts 32 hours after lesioning. Complementary immunocytochemistry studies identified both infiltrating microglia/monocytes and injured neurons as the principal CCR5-immunoreactive cells. These results provide the first evidence that acute excitotoxic injury regulates CCR5 expression in the developing rat brain.

Functional comparisons among members of the poxvirus T1/35kDa family of soluble CC-chemokine inhibitor glycoproteins

Many poxviruses express a 35-40-kDa secreted protein, termed "T1" (for leporipoxviruses) or "35kDa" (for orthopoxviruses), that binds CC-chemokines with high affinity but is unrelated to any known cellular proteins. Many previously identified poxvirus cytokine-binding proteins display strict species ligand-binding specificity. Because the T1 and 35kDa proteins share only 40% amino acid identity, we compared the abilities of purified myxoma virus-T1 (M-T1) and vaccinia virus (strain Lister)- and rabbitpox virus-35kDa proteins to inhibit human CC-chemokines in vitro. All three proteins were equally effective in preventing several human CC-chemokines from binding to target chemokine receptors and blocking subsequent intracellular calcium release. The inhibitory affinities were comparable (Ki = 0.07-1.02 nM). These proteins also displayed similar abilities to inhibit (IC50 = 6.3-10.5 nM) human macrophage inflammatory protein-1alpha-mediated chemotaxis of human monocytes. None of the viral proteins blocked interleukin-8-mediated calcium flux or chemotaxis of human neutrophils, confirming that the biological specificity of the T1/35kDa family is targeted inhibition of CC-chemokines. Despite the significant sequence divergence between the leporipoxvirus T1 and orthopoxvirus 35kDa proteins, our data suggest that their CC-chemokine binding and inhibitory properties appear to be species nonspecific and that the critical motifs most likely reside within the limited regions of conservation.

Doppler pressure half-time method of assessing mitral valve area: aortic insufficiency does not adversely affect validity

OBJECTIVES

This study evaluated the effect of aortic insufficiency on the correlation of pressure half-time-derived mitral valve area with each of 2 standards for mitral valve area (planimetry and cardiac catheterization) in a prospectively assembled cohort of patients scheduled for percutaneous balloon mitral commissurotomy.

BACKGROUND

Although Doppler pressure half-time has been validated as a method for assessing mitral valve area, most previous studies have suggested that this noninvasive technique overestimates mitral valve area in the setting of coexistent aortic insufficiency.

METHODS AND RESULTS

Echocardiography and cardiac catheterization were performed on 212 consecutive patients scheduled for percutaneous balloon mitral commissurotomy. After excluding 35 patients who did not have aortography, the rest were divided into a "no aortic insufficiency [AI] group" (n = 146) including those with trivial or no aortic insufficiency at catheterization and an "AI group" (n = 31 ) including those with mild or moderate aortic insufficiency. The pressure half-time mitral valve area tended to slightly underestimate invasive valve area by 0.04 cm2 in the AI group and to slightly overestimate invasive valve area by 0.06 cm2 in the no AI group. This difference between the groups was not statistically significant (P = .13). The pressure half-time mitral valve area tended to underestimate planimetered valve area by 0.11 cm2 in the AI group and by 0.10 cm2 in the no AI group. There was no difference between the 2 groups (P = .94). Potential confounders that could theoretically mask the effect of aortic insufficiency on the pressure half-time (including age, heart rate, blood pressure, left ventricular diastolic pressure, ejection fraction, mitral regurgitation, and atrial fibrillation) were excluded by multivariable analyses.

CONCLUSIONS

The pressure half-time method of determining mitral valve area is not adversely affected by mild to moderate aortic insufficiency. This finding has implications for the utility of this technique in the rheumatic valvular disease population, in which mitral and aortic valve disease frequently coexist.

Role for neuronally derived fractalkine in mediating interactions between neurons and CX3CR1-expressing microglia

A recently identified chemokine, fractalkine, is a member of the chemokine gene family, which consists principally of secreted, proinflammatory molecules. Fractalkine is distinguished structurally by the presence of a CX3C motif as well as transmembrane spanning and mucin-like domains and shows atypical constitutive expression in a number of nonhematopoietic tissues, including brain. We undertook an extensive characterization of this chemokine and its receptor CX3CR1 in the brain to gain insights into use of chemokine-dependent systems in the central nervous system. Expression of fractalkine in rat brain was found to be widespread and localized principally to neurons. Recombinant rat CX3CR1, as expressed in Chinese hamster ovary cells, specifically bound fractalkine and signaled in the presence of either membrane-anchored or soluble forms of fractalkine protein. Fractalkine stimulated chemotaxis and elevated intracellular calcium levels of microglia; these responses were blocked by anti-CX3CR1 antibodies. After facial motor nerve axotomy, dramatic changes in the levels of CX3CR1 and fractalkine in the facial nucleus were evident. These included increases in the number and perineuronal location of CX3CR1-expressing microglia, decreased levels of motor neuron-expressed fractalkine mRNA, and an alteration in the forms of fractalkine protein expressed. These data describe mechanisms of cellular communication between neurons and microglia, involving fractalkine and CX3CR1, which occur in both normal and pathological states of the central nervous system.

Partially anomalous pulmonary venous connection: demonstration of dual drainage allowing nonsurgical correction

We describe a novel percutaneous approach for correction of partially anomalous pulmonary venous connection. We describe two cases of dual pulmonary venous drainage where embolization of the anomalous pulmonary venous connection was successful.

In vivo inhibition of CC and CX3C chemokine-induced leukocyte infiltration and attenuation of glomerulonephritis in Wistar-Kyoto (WKY) rats by vMIP-II

Chemokines play a central role in immune and inflammatory responses. It has been observed recently that certain viruses have evolved molecular piracy and mimicry mechanisms by encoding and synthesizing proteins that interfere with the normal host defense response. One such viral protein, vMIP-II, encoded by human herpesvirus 8, has been identified with in vitro antagonistic activities against CC and CXC chemokine receptors. We report here that vMIP-II has additional antagonistic activity against CX3CR1, the receptor for fractalkine. To investigate the potential therapeutic effect of this broad-spectrum chemokine antagonist, we studied the antiinflammatory activity of vMIP-II in a rat model of experimental glomerulonephritis induced by an antiglomerular basement membrane antibody. vMIP-II potently inhibited monocyte chemoattractant protein 1-, macrophage inflammatory protein 1beta-, RANTES (regulated on activation, normal T cell expressed and secreted)-, and fractalkine-induced chemotaxis of activated leukocytes isolated from nephritic glomeruli, significantly reduced leukocyte infiltration to the glomeruli, and markedly attenuated proteinuria. These results suggest that molecules encoded by some viruses may serve as useful templates for the development of antiinflammatory compounds.

Chemokine receptor expression in cultured glia and rat experimental allergic encephalomyelitis

Chemokines are a group of pro-inflammatory peptides that mediate leukocyte migration and activation. Several members of the chemokine family have been shown to be synthesized by cells of the central nervous system (CNS). To begin to address the role of chemokine receptors in CNS physiology, we identified, by molecular cloning techniques, the rat orthologs of the chemokine receptors, CCR2, CCR3, CCR5, and CXCR4. CCR2 and CCR5 expression was detected in rat spleen, lung, kidney, thymus and macrophages; CCR5 mRNA was also detected in rat brain. Primary cultures of rat microglia expressed CCR5 mRNA that was regulated by IFN-gamma, while both cultured astrocytes and microglia were found to contain mRNA for CXCR4 and CX3CR1. Induction of experimental allergic encephalomyelitis (EAE) in the rat was accompanied by increased levels of CCR2, CCR5, CXCR4, and CX3CR1 mRNAs in the lumbar spinal cords of animals displaying clinical signs of the disease. These data identify the rat orthologs of chemokine receptors and demonstrate that brain, spinal cord, and cultured glial cells express chemokine receptors that can be regulated both in vitro and in vivo.

Expression of CCR5 increases during monocyte differentiation and directly mediates macrophage susceptibility to infection by human immunodeficiency virus type 1

The stage of differentiation and the lineage of CD4+ cells profoundly affect their susceptibility to infection by human immunodeficiency virus type 1 (HIV-1). While CD4(+) T lymphocytes in patients are readily susceptible to HIV-1 infection, peripheral blood monocytes are relatively resistant during acute or early infection, even though monocytes also express CD4 and viral strains with macrophage (M)-tropic phenotypes predominate. CCR5, the main coreceptor for M-tropic viruses, clearly contributes to the ability of CD4+ T cells to be infected. To determine whether low levels of CCR5 expression account for the block in infection of monocytes, we examined primary monocyte lineage cells during differentiation. Culturing of blood monocytes for 5 days led to an increase in the mean number of CCR5-positive cells from <20% of monocytes to >80% of monocyte-derived macrophages (MDM). Levels of CCR5 expression per monocyte were generally lower than those on MDM, perhaps below a minimum threshold level necessary for efficient infection. Productive infection may be restricted to the small subset of monocytes that express relatively high levels of CCR5. Steady-state CCR5 mRNA levels also increased four- to fivefold during MDM differentiation. Infection of MDM by M-tropic HIV-1JRFL resulted in >10-fold-higher levels of p24, and MDM harbored >30-fold more HIV-1 DNA copies than monocytes. In the presence of the CCR5-specific monoclonal antibody (MAb) 2D7, virus production and cellular levels of HIV-1 DNA were decreased by >80% in MDM, indicating a block in viral entry. There was a direct association between levels of CCR5 and differentiation of monocytes to macrophages. Levels of CCR5 were related to monocyte resistance and macrophage susceptibility to infection because infection by the M-tropic strain HIV-1JRFL could be blocked by MAb 2D7. These results provide direct evidence that CCR5 functions as a coreceptor for HIV-1 infection of primary macrophages.

The Ross procedure: shorter hospital stay, decreased morbidity, and cost effective

BACKGROUND

The Ross procedure has become an accepted and sometimes preferred alternative to mechanical aortic valve replacement. One criticism of the Ross procedure is that it may have a higher operative mortality, morbidity, and cost. Several groups have shown that this operation can be performed safely with less than 3% mortality. The issue of higher cost has not been resolved. In this retrospective study we compared a consecutive group of patients undergoing the Ross procedure with an age- and disease-matched group of patients who underwent mechanical aortic valve replacement.

METHODS

From 1993 to 1996, 22 consecutive adult patients (age range, 20 to 57 years; mean, 38 +/- 14 years) underwent the Ross procedure. Twenty-seven patients (age range, 17 to 57 years; mean, 41 +/- 10 years) underwent mechanical aortic valve replacement between 1991 and 1996. The hospital cost (in 1996 dollars) and postoperative length of stay were calculated for each patient using Transition I, a hospital-wide cost accounting system.

RESULTS

There was no hospital mortality in either group. The incidence of significant valve-related complication was 5% (1/22 patients) in the Ross procedure group and 22% (6/27 patients) in the mechanical valve group. There were two late deaths in the group with mechanical aortic valve replacement. The length of stay for the Ross procedure group was 5.9 +/- 2.1 days, versus 8 +/- 1.85 days for the mechanical valve group (p < 0.01). The mean hospital costs were not significantly different, $23,140 +/- $7,825 for the mechanical valve group and $23,226 +/- $6,960 for the group having the Ross procedure.

CONCLUSIONS

The data from this review demonstrate that the Ross procedure can be done safely, with short hospital stays, decreased morbidity, and costs comparable with those of standard mechanical aortic valve replacement in patients with isolated aortic valve disease.