What is the utility of routine ANA testing in predicting development of biological DMARD-induced lupus and vasculitis in patients with rheumatoid arthritis? Data from a single-centre cohort.

OBJECTIVE: To determine whether serial ANA testing predicts biological disease modifying antirheumatic drugs (bDMARD)-associated ANA/dsDNA production in patients with rheumatoid arthritis (RA). METHODS: Serial autoantibody profiles, bDMARD treatment sequences and clinical data were collected from patients identified from our database that since 2005 received (i) a first bDMARD (tumour necrosis factor inhibitor (TNFi)) and (ii) tocilizumab and/or abatacept. RESULTS: Of over 1000 patients, 454 RA patients received a first TNFi. Infliximab group demonstrated higher ANA seroconversion rates (31.2%) compared with etanercept (11.8%) and adalimumab (16.1%) (p<0.001). Median (range) treatment duration prior to ANA seroconversion was 10.9 (1.3-80.0) months. Positive anti-dsDNA titres of IgG class (median (range) of 77 IU/mL (65-109)) were noted in six (7.2%) patients, within a median (range) of 2.0 (0.8-4.2) years. Three patients developed classifiable lupus. 4 of 74 (5.4%) primary non-responders and 24 of 111 (21.6%) secondary non-responders developed positive ANA antibodies after TNFi initiation (p=0.003). Seven (9.5%) tocilizumab-treated patients changed to positive ANA; five (8.6%) abatacept-treated patients changed to positive ANA status. CONCLUSIONS: This study demonstrates no utility of serial ANA/dsDNA testing that could be used to predict onset of seroconversion and therefore the development of lupus/vasculitis. An association however between seroconversion and the development of a secondary non-response to bDMARD therapy is suggested.

Direct comparison of runoff of residual and knockdown herbicides in sugarcane using a rainfall simulator finds large difference in runoff losses and toxicity relative to diuron.

Runoff losses of herbicides have rarely been compared simultaneously under the same conditions. Our aim was to directly compare herbicide runoff losses, normalised for the amount present (relative runoff loads) and in absolute terms. Toxicity and runoff concentrations were combined to provide a risk ranking relative to diuron. Four rainfall simulation trials were conducted in sugarcane in the Great Barrier Reef catchment. Herbicides studied were older PSII residuals (atrazine, ametryn, diuron, hexazinone), alternative residuals (isoxaflutole, imazapic, metribuzin, metolachlor, pendimethalin) and knockdown herbicides (glyphosate, 2,4-D, fluroxypyr) and the tracer bromide (Br). Simulations were conducted two days after spraying, before differences due to half-lives were apparent. Two trials had bare soil and two had sugarcane trash. Herbicide runoff losses and concentrations were closely related to the amount applied, runoff amounts and partitioning coefficients. Relative runoff losses and absolute losses were similar for most older and alternative residual herbicides, 2,4-D and Br. Glyphosate and pendimethalin relative runoff losses were low, due to greater sorption. Isoxaflutole, imazapic, and fluroxypyr are applied at much lower rates and runoff losses were low. Herbicides were lost in the dissolved phase, except pendimethalin. There was a large range in toxicity relative to diuron. There is a range of herbicide choices posing less offsite risk than diuron and ametryn, which have high application rates and high toxicity. Herbicide choice should consider application rate, runoff losses, sorption, and toxicity.

NT5E (CD73) is epigenetically regulated in malignant melanoma and associated with metastatic site specificity.

BACKGROUND: Novel prognostic biomarkers and therapeutic strategies are urgently required for malignant melanoma. Ecto-5-prime-nucleotidase (NT5E; CD73) overexpression has been reported in several human cancers. The mechanism(s) underlying deregulated expression and the clinical consequences of changes in expression are not known. METHODS: We used RT-PCR, qPCR, methylation-specific PCR and pyrosequencing to analyse expression and regulation of NT5E in malignant melanoma cell lines and primary and metastatic melanomas. RESULTS: NT5E is subject to epigenetic regulation in melanoma. NT5E mRNA is downregulated by methylation-dependent transcriptional silencing in the melanoma cell lines SKMel2, SKMel23, WM35, Mel501, Mel505 and C81-61 and expression is reactivated by azacytidine. In contrast, the CpG island is unmethylated and the gene expressed in cultured normal melanocytes. In clinical cases of melanoma, methylation in the NT5E CpG island occurs in both primary and metastatic melanomas and correlates with transcriptional downregulation of NT5E mRNA. Relapse with metastatic disease, particularly to the visceral sites and brain, is more common in primary melanomas lacking NT5E methylation. Primary melanomas with methylation in NT5E show limited metastatic potential or more commonly metastasise predominantly to nodal sites rather than viscera and brain (P=0.01). CONCLUSION: Deregulation of NT5E expression in melanoma occurs via epigenetic changes in the NT5E CpG island. Confirmation of our results in larger clinical series would support the candidacy of NT5E as a clinical biomarker in melanoma, which could be applied in both primary and relapsed disease. Inhibition of NT5E may have therapeutic potential in melanoma, particularly in patients with more aggressive disease metastatic to viscera or the brain.

NT5E CpG island methylation is a favourable breast cancer biomarker.

BACKGROUND: Relapse risk assessment and individual treatment recommendations remain suboptimal for breast cancer patients. In the light of existing preclinical and clinical data, we studied NT5E (5'-nucleotidase, ecto) expression and NT5E CpG island methylation in breast cancer. METHODS: We used RT-PCR, qPCR, methylation-specific PCR and pyrosequencing to analyse NT5E in breast carcinoma cell lines and primary and breast carcinomas. RESULTS: NT5E CpG island methylation was inversely associated with NT5E expression in breast carcinoma cell lines. In clinical series, patients whose primary tumours had NT5E CpG island methylation were less likely to develop metastasis (P=0.003, OR=0.34, 95% CI: 0.17-0.69). In 3/4 paired samples, NT5E was methylated in primary tumours and demethylated in CNS metastases. Patients progressing to non-visceral as compared with visceral metastases were more likely to have NT5E CpG island methylation in primary tumours (P=0.01, OR=11.8). Patients with tumours lacking detectable methylation had shorter disease-free survival (DFS) (P=0.001, HR=2.7) and overall survival (OS) (P=0.001, HR=3). The favourable prognostic value of NT5E methylation was confirmed in oestrogen receptor negative (P=0.011, HR=3.27, 95% CI: 1.31-8.12) and in triple negative cases (P=0.004; HR=6.2, 95% CI: 1.9-20). Moreover, we observed a more favourable outcome to adjuvant chemotherapy in patients whose tumours were positive for NT5E CpG island methylation: DFS (P=0.0016, HR=5.1, 95% CI: 1.8-14.37) and OS (P=0.0005, HR=7.4, 95% CI: 2.416-23.08). CONCLUSION: NT5E CpG island methylation is a promising breast cancer biomarker.

Use of the Portsmouth Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity ('P-POSSUM') to predict morbidity in patients undergoing surgery with reconstruction for temporal bone malignancy.

OBJECTIVE: The Portsmouth Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity ('P-POSSUM') is a two-part scoring system that includes a physiological assessment and a measure of operative severity. This study sought to determine whether risk estimates for this scoring system could be used in major head and neck reconstructive surgery. METHOD: A retrospective review was performed of patients undergoing resection for a temporal bone malignancy in a single head and neck centre in Dublin, Ireland, from 2002 to 2021. RESULTS: The mean ± standard deviation morbidity estimate calculated using the scoring system was 47.6 per cent ± 19.5 per cent. The actual rate of complications was 47 per cent. The optimal cut-off for the scoring system was calculated using the Youden index from the receiver operating characteristic curve, which was 40.5 per cent in this case. CONCLUSION: The study indicates that the Portsmouth Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity is a useful tool for predicting morbidity risk in patients undergoing head and neck resection with reconstruction for temporal bone malignancies.

Burden of Uterine Fibroids: An African Perspective, A Call for Action and Opportunity for Intervention.

Black women carry the burden of uterine fibroids, (AKA uterine leiomyomas), at a much higher rate than their racial counterparts. Thus, increasing awareness and discovering a solution to an endemic problem that plagues Sub-Saharan Africa is of critical importance, not only for the region itself, but also for the medical community globally. A collaborative, patient oriented, cost effective, and culturally sensitive approach must be at the forefront of this endeavor. While the exact pathogenesis of uterine fibroid development remains elusive, the racial disparity is well documented. Moreover, in the developed world, women are able to seek treatment through surgical and non-surgical means; however, sub-Saharan regions face their own challenges that, if not addressed, can ultimately extinguish the lives of many suffering women. Unfortunately, the literature is scarce on how to prevent fibroid development, which may be critical for women who do not have access to effective interventions. Recent research from our group and others has shown that vitamin D deficiency plays an important role in fibroid development and may be a preventable risk factor. Daily vitamin D supplementation is a low cost, effective intervention that could be implemented throughout the Sub-Saharan region. Similarly, education and increased awareness as to the nature and symptoms of uterine fibroids could improve the quality of life, remove negative social stigma, and reduce morbidity and mortality rates in women who seek medical care with advanced uterine fibroids.

Mutations in the cardiac transcription factor NKX2.5 affect diverse cardiac developmental pathways.

Heterozygous mutations in NKX2.5, a homeobox transcription factor, were reported to cause secundum atrial septal defects and result in atrioventricular (AV) conduction block during postnatal life. To further characterize the role of NKX2.5 in cardiac morphogenesis, we sought additional mutations in groups of probands with cardiac anomalies and first-degree AV block, idiopathic AV block, or tetralogy of Fallot. We identified 7 novel mutations by sequence analysis of the NKX2.5-coding region in 26 individuals. Associated phenotypes included AV block, which was the primary manifestation of cardiac disease in nearly a quarter of affected individuals, as well as atrial septal defect and ventricular septal defect. Ventricular septal defect was associated with tetralogy of Fallot or double-outlet right ventricle in 3 individuals. Ebstein's anomaly and other tricuspid valve abnormalities were also present. Mutations in human NKX2.5 cause a variety of cardiac anomalies and may account for a clinically significant portion of tetralogy of Fallot and idiopathic AV block. The coinheritance of NKX2.5 mutations with various congenital heart defects suggests that this transcription factor contributes to diverse cardiac developmental pathways.

Silicon and silicone levels in patients with silicone implants.

Although a potential link between silicone gel breast implants and autoimmune connective tissue disease has been suggested, none has been proven. The potential role of silicone as an immune adjuvant remains very controversial. Currently available techniques do not easily allow precise measurements of silicone in tissues. However, all compounds containing silicon (which would include silicone) can be measured accurately. The present study was designed to measure silicon levels in the fibrous capsules of patients with silicone-gel breast implants, saline breast implants and silicone inflatable penile prostheses. Baseline control silicon levels were obtained from the breast tissue of patients undergoing breast reduction, who had no exposure to breast implants. All silicon measurements were carried out using atomic absorption spectrometry with a graphite furnace. The mean silicon levels in 16 breast tissue control samples from 8 patients undergoing breast reduction varied from 0.046 to 0.742 micrograms/g dry weight, with the median mean being 0.0927. The median silicon level in capsules from 6 patients with saline implants was 7.7 micrograms/g (range 36.6). The median silicon level in capsules from 5 patients with silicone inflatable penile prostheses was 19.5 micrograms/g (range 34.8). Although the levels of silicon in capsules of patients with saline breast prostheses and penile implants were higher than in control samples, they were much lower than those from the capsules of the 58 gel implants (median 9979 micrograms/g). Of the 58 silicone gel breast implants (from 20 patients with bilateral implant removal and 18 patients with unilateral removal) which had been inserted from 1974 to 1990, 28 were intact, 8 had pinhole leaks, and 22 were ruptured. Median capsule silicon levels and ranges for all 58 implants, for intact only, for leaking, and for ruptured were: 9979 (152,000), 10,477 (88,703), 6592 (65,396), and 9922 (152,387) micrograms/g respectively. There were no significant differences in silicon levels associated with implant status, duration in situ, or year of implantation. Capsule contracture was not associated with higher levels of capsule silicon. Capsule silicon levels were about 10(6) times higher than previously assayed blood silicon levels. This may be because silicone released from implants remains localized in capsular tissue, or because blood-borne silicone is quickly excreted. Using 29Si nuclear magnetic resonance spectroscopy, no detectable silicone was found in the blood of 7 control women and 7 women with silicone-gel implants (5 with known implant rupture).

Pericardial effusion and cardiac tamponade in pediatric stem cell transplant recipients.

Pericardial effusion and cardiac tamponade is a rarely reported complication following stem cell transplant (SCT). The incidence among pediatric SCT recipients is not well defined. To assess the frequency of clinically significant pericardial effusions, we retrospectively examined clinically significant cardiac effusions at our center. Between January of 1993 and August 2004, clinically significant pericardial effusions were identified in nine of 205 patients (4.4%). The median age at the time of transplant was 9 years (range 0.6-18 years) and seven received an allogeneic transplant. All nine had normal cardiac function prior to transplant. The effusion developed at a median of 30 days (range 18-210 days). All allogeneic recipients had acute or clinically extensive graft-versus-host disease (GVHD) at the time the effusion was diagnosed. Seven patients (78%) required pericardiocentesis or surgical creation of a pericardial window. No patient died as a complication of the effusion or the therapeutic procedures. Clinically significant pericardial effusions are more common than previously reported in pediatric SCT recipients. Acute and chronic GVHD is an associated factor.

The role of polymer membrane formation in sustained release drug delivery systems.

A discussion of the role of polymer membrane-based drug delivery systems is presented. This is followed with a review of recent studies in our laboratories of the membrane formation and drug delivery characteristics of injectable polymer solution platforms. Attention is focused on the role of depot formulation in terms of solvent quality and water miscibility and polymer type (amorphous versus crystallizable), as well as the effects of bath-side additives on the in vitro release behavior. A quantitative model describing the protein release dynamics in fast phase inverting systems (FPI) is also discussed.

A model for drug release from fast phase inverting injectable solutions.

A model is developed to describe protein release kinetics from injectable, polymer solution depots which undergo rapid phase inversion on injection. The model consists of a polymer-rich phase and a solvent-rich phase, consistent with experimentally observed phase inversion morphology. Equations in the polymer-rich phase are based on diffusion-reaction mass balances for solvent, water and dissolved drug, and the rate of dissolution of dispersed drug particles. Equations in the water-rich phase are also of the diffusion-reaction type. Transport parameters in the polymer-rich phase are coupled to the ternary thermodynamics through friction formalism, and remaining parameters are estimated from literature data, leaving two free parameters: volume fraction of water-rich phase (epsilon) and k, the mass-transfer coefficient for bath-side transfer of the protein. Variations of these parameters lead to predictions of release profiles that vary from a rapid, burst-like behavior followed by a locking-in of the polymer-rich phase, to a uniform, zero-order profile. Comparisons are made to lysozyme release data for three systems: PLGA solutions in N-methlypyrollidinone (NMP), PLA solutions in NMP, and the latter with added Pluronic. Good agreement between model predictions and data is shown; in particular, the transition from rapid release to zero-order kinetics that occurs on addition of Pluronic is illustrated.

Modified Norwood operation for hypoplastic left heart syndrome.

BACKGROUND: We examined early results in infants with hypoplastic left heart syndrome undergoing the Norwood operation with perioperative use of inhaled nitric oxide and application of extracorporeal membrane oxygenation. METHODS: Medical records were reviewed retrospectively. RESULTS: Between April 1997 and March 2001, 50 infants underwent a modified Norwood operation for hypoplastic left heart syndrome. Mean age at operation was 7.5 +/- 5.7 days, and mean weight was 3.1 +/- 0.5 kg. Five infants had a delayed operation because of sepsis. The mean diameter of the ascending aorta by echocardiography was 3.6 +/- 1.8 mm. Ductal cannulation was used to establish cardiopulmonary bypass in all patients. Mean circulatory arrest time was 39.4 +/- 4.8 minutes. The size of the pulmonary-systemic shunt was 3.0 mm in 6 infants, 3.5 mm in 37, and 4.0 mm in 7. Infants with persistent hypoxia (partial pressure of oxygen < 30 mm Hg) received nitric oxide after they were weaned from cardiopulmonary bypass. Extracorporeal membrane oxygenation was initiated in 8 infants in the pediatric intensive care unit primarily for low cardiac output and in 8 in the operating room because of the inability to separate them from cardiopulmonary bypass. The 30-day mortality rate was 22% (11 of 50 patients), and the hospital mortality rate was 32% (16 of 50 patients). Mean follow-up was 17 months. Ten patients (20%) underwent stage-two repair, with one operative death. One survivor had a Fontan procedure, and 2 underwent heart transplantation, with one death. CONCLUSIONS: Early application of extracorporeal membrane oxygenation for hemodynamic instability and selective use of nitric oxide for persistent hypoxia in the immediate postoperative period may improve survival of patients with hypoplastic left heart syndrome. Renal failure requiring hemofiltration during extracorporeal membrane oxygenation (p < 0.05) and cardiopulmonary arrest in the pediatric intensive care unit (p < 0.05) were predictors of hospital mortality.

Analysis of genetically modified plant gene expression using GUS fluorimetry.

A fluorimetric assay method for the analysis of beta-glucuronidase (GUS) reporter gene expression in genetically modified plants is described. Optimization of this method for woody plants and a statistical approach suitable for comparisons of gene expression in different transformants or tissues of the same plant is described. Example data from elm (Ulmus procera) SR4 regenerant plants, shown to be genetically modified by PCR and DNA-DNA hybridizations, in which higher GUS expression levels are found in stems than in leaves demonstrates the utility of this approach.

Role of crystallization in the phase inversion dynamics and protein release kinetics of injectable drug delivery systems.

The role of polymer crystallization in the phase inversion dynamics and in vitro protein release kinetics of semi-crystalline poly (epsilon-caprolactone) and amorphous poly (D,L-lactide) (PDLA) blend solutions has been examined using high performance liquid chromatography (HPLC), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC) techniques. Varying the degree of crystallizability of the solutions led to the emergence of two general classes of depots. Depots with a high degree of crystallinity are characterized by porous morphologies indicative of solid-liquid (s--l) de-mixing and delayed burst release profiles. Alternatively, depots with a low degree of crystallinity are characterized by dense morphologies formed by mild liquid-liquid (l--l) phase separation and slow, uniform protein release rates. An interpretation of these results in terms of a qualitative model for the protein release mechanism is also given.

The effect of Pluronic on the protein release kinetics of an injectable drug delivery system.

A new class of injectable controlled release depots has been prepared by incorporating materials that preferentially segregate during phase inversion. These consist of blends of poly(ethylene oxide) (PEO)/poly(propylene oxide) (PPO)/poly(ethylene oxide) (PEO) triblock copolymers (Pluronics) with poly(D,L-lactide) (PDLA)/1-methyl-2-pyrrolidinone (NMP) solutions. The effects of preferential segregation on the phase inversion dynamics and in vitro protein release kinetics were examined using dark ground imaging, high performance liquid chromatography (HPLC), scanning electron microscopy (SEM), and confocal microscopy. Variations in Pluronic concentration and molecular weight had an insignificant effect on the internal depot morphologies, however, increasing the concentration and molecular weight did result in increased phase separation rates and, surprisingly, a decrease in the magnitude of the protein burst, though the release profiles still retained a typical burst-type shape. Additionally, increasing the Pluronic concentration beyond a critical point resulted in a transition from a burst-type profile to an extended-release profile. An interpretation of these results in terms of a qualitative model for the protein release mechanism is also given.

Phase inversion dynamics of PLGA solutions related to drug delivery. Part II. The role of solution thermodynamics and bath-side mass transfer.

The role of solvent properties and bath-side composition on the phase inversion dynamics and in vitro protein release kinetics of polylactic-co-glycolic acid (PLGA) solutions has been examined using dark ground imaging, in vitro release rate, and SEM techniques. Thermodynamic phase diagrams for three model systems (PLGA in 1-methyl-2-pyrrolidinone (NMP), triacetin, and ethyl benzoate) suggest two general classes of precipitation behavior, depending on the relative solvent strength and water miscibility. Drug release from the NMP-based system is primarily governed by the dynamics of phase inversion and exhibits a distinct burst region followed by a much slower release. Alternatively, depots with low solvent/water affinity (PLGA in triacetin or ethyl benzoate) undergo much slower phase inversion, resulting in a less porous, more fluid, two-phase structure that also releases protein more uniformly. Addition of a small chain triglyceride or organic salt to the aqueous receptor bath also evokes a significant increase in the mass transfer rate of protein from the low solvent/non-solvent affinity depots. An interpretation of these results in terms of a qualitative model for the protein release mechanism is also given.

Phase inversion dynamics of PLGA solutions related to drug delivery.

Dark ground optical microscopy, electron microscopy, and high performance liquid chromatography (HPLC) have been used to quantify the effects of formulation changes on the phase inversion dynamics and in vitro drug release properties of a PLGA-based drug delivery system. Gel growth rates and water influx rates are determined from plots of the square of the respective front motion with time. Results show that additives that accelerate the solution gelation rate at constant morphology result in high initial release rates. Conversely, additives that slow the rate of gelation dramatically reduce the initial drug release rate and lead to a more dense sponge-like morphology. Moreover, the phase inversion dynamics and morphology are the same regardless of whether the solutions are quenched with water, a PBS buffer solution or horse serum.

Changes in serum CK-MB mass after coronary artery bypass surgery.

We assessed the release of creatine kinase MB as both mass and activity during the postoperative period following cardiac surgery. CK-MB mass was determined by enzyme immunoassay using reagents obtained from Hybritech. CK-MB activity was determined both by agarose electrophoresis and by an immunochemical method. Fifty-five patients who underwent coronary artery bypass surgery and 52 control subjects who had orthopedic surgery were selected for study. Serial serum samples were collected following surgery and total LD, CK, AST, LD-1, CK-MB mass, and CK-MB activity determined. Results were compared to each other and to surgical parameters. All patients exhibited significant CK-MB mass and activity after surgery and peak serum levels were 6-94 micrograms/L and 12-84 U/L, respectively. CK-MB mass correlated with CK-MB activity on paired samples (r = 0.94). Total AST and CK activities correlated with CK-MB mass (r = 0.60, and 0.63, respectively). Peak levels of CK-MB mass correlated significantly with peak MB activity (r = 0.88), peak LD-1 (r = 0.62), peak AST (r = 0.71), and time on pump (r = 0.54). Similar correlations were also seen between peak CK-MB activity and these parameters. No relationship could be identified between extent of CK-MB mass release and number of grafts, degree of hypothermia, or minimum PaO2. The time course of CK-MB mass release exhibited 85% concordance with CK-MB activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Selenium deficiency and cardiomyopathy in acquired immunodeficiency syndrome.

Selenium deficiency is common in patients with human immunodeficiency virus infection and may contribute to the development of cardiomyopathy. A 5-year-old boy with congenital human immunodeficiency virus infection developed cardiomyopathy. Evaluation for reversible causes of cardiomyopathy was notable for the diagnosis of selenium deficiency. Cardiac function improved on selenium supplementation. The role of selenium in cardiac dysfunction and the need for nutritional evaluation and supplementation of malnourished patients with acquired immunodeficiency syndrome is discussed.

Low incidence of significant valvar insufficiency following retrograde aortic radiofrequency catheter ablation in young patients.

The incidence of significant valvar insufficiency at late (<6 month) follow-up was retrospectively evaluated in 27 young patients (age 4. 0-18.0 years) undergoing 29 ablation procedures via the retrograde aortic approach for left-sided accessory connections in whom pre-ablation and post-ablation echocardiograms were available for review. Valvar insufficiency was graded using color flow techniques as absent, trivial, mild, moderate, or severe by blinded reviewers. Ablation was acutely successful via the retrograde approach in 25 of 29 procedures among these 27 patients. Successful ablation was ultimately achieved in all 27 patients. At baseline, 7 patients had evidence of trivial or mild mitral insufficiency, and no patient had aortic insufficiency. Three patients had evidence of impaired left ventricular systolic performance in the presence of manifest pre-excitation. At follow-up, pre-existing mitral insufficiency resolved in 5/7 patients, and persisted in 2 patients. New mitral insufficiency was evident in 3 patients, and new aortic insufficiency was transiently evident in 1 patient following ablation (all trivial). Institutional experience (mean rank 10 cases vs. 33 cases, p <.0005), and lower patient weight (29.7 vs. 56.3 kilograms, p =.01) were the only factors associated with the development of new valvar insufficiency. Valvar insufficiency could not be detected by careful auscultation in any patient and was deemed clinically insignificant in all patients. We conclude that ablation of left-sided accessory connections can be performed via the retrograde aortic approach without creating clinically significant valvar insufficiency.