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Biomedical subjects

Andrew Wang

Publications and source records attributed to Andrew Wang.

29 records · Page 2Linked to original sources
PubMed2004

Five-year clinical and echocardiographic evaluation of the Das AngelWings atrial septal occluder.

BACKGROUND: The late outcome of patients treated with atrial septal occluder devices remains incompletely defined. The purpose of this study was to assess the late outcome (range 4-7 years postprocedure) of patients in whom the Das AngelWings septal occluder device was implanted in the atrial septum. We report the clinical and echocardiographic outcome, at an average of 5 years following the procedure, of patients treated with the Das AngelWings device used to close either a secundum atrial septal defect (ASD) or a patent foramen ovale (PFO). METHODS: Thirty-two patients underwent successful percutaneous closure of an atrial septal closure, patent foramen ovale, or fenestration in the lateral tunnel of their Fontan with the Das AngelWings device between June 1995 and March 1998 at Duke University Medical Center. Two of the 32 patients were lost to follow-up. The remaining 30 patients were divided into 3 groups based on indication for device implantation. Group 1 consisted of 14 patients with a secundum ASD and predominantly left-to-right atrial shunting. Group 2 consisted of 8 patients who had a PFO and who suffered a thromboembolic event. Group 3 (compassionate use) consisted of 10 patients with multiple comorbid medical problems with predominantly right-to-left shunting at the atrial level causing hypoxemia. Eight of the patients in group 3 were severely ill at the time of device implantation. The 2 remaining patients in group 3 underwent AngelWings implantation for closure of right-to-left shunting through a Fontan fenestration. Mean follow-up was 59 months. RESULTS: There was no device embolization. No patient in the ASD or PFO/stroke group had a clinical complication. By radiographic examination, 2 of 27 patients had evidence of fracture of the nitinol framework at 2-year follow-up. Residual shunting was present in 44% at 24 hours, 20% at 1 year, and 18.8% at 2 years by use of Doppler color flow imaging and/or microcavitation echocardiographic studies. Mild mitral regurgitation caused by the AngelWings device occurred in 1 patient. One patient in the compassionate use group had a subsequent neurologic event. Five of the 10 patients in the compassionate use group died of comorbid illnesses in follow-up, none directly related to device complications. CONCLUSION: The late clinical outcome of secundum ASD and PFO/stroke patients in this study demonstrates that Das AngelWings closure of the atrial septum is effective and safe. These data are encouraging with respect to the expanding use of other percutaneously implanted ASD occlusion devices, although late clinical safety and efficacy data are needed for the specific devices being implanted.

Adolescent↗
PubMed2004

Left main coronary artery-to-pulmonary artery fistula with severe aneurysmal dilatation.

Coronary artery fistulas (CAF) are rare abnormalities that can be symptomatic or asymptomatic. Most drain into the right ventricle or pulmonary artery, though a variety of other drainage sites have been reported. We report the results of the surgical closure of a symptomatic left coronary-to-pulmonary artery fistula associated with a giant 10-cm aneurysm and discuss the management of coronary artery fistulas.

Arterio-Arterial Fistula↗
PubMed2003

Fenoldopam mesylate for the prevention of contrast-induced nephropathy: a randomized controlled trial.

CONTEXT: The development of contrast-induced nephropathy in patients undergoing invasive cardiac procedures is associated with a marked increase in cardiovascular morbidity and mortality. Fenoldopam mesylate, a specific agonist of the dopamine-1 receptor, preserves renal blood flow after iodinated contrast administration and has shown promise in ameliorating contrast nephropathy in previous observational and small randomized trials. OBJECTIVE: To examine the efficacy of fenoldopam mesylate in preventing contrast nephropathy after invasive cardiovascular procedures. DESIGN: Prospective, placebo-controlled, double-blind, multicenter randomized trial with serial serum creatinine levels measured at a central biochemistry laboratory (at baseline and 1, 24, 48, and 72 to 96 hours after study drug administration) and 30-day clinical follow-up. PATIENTS AND SETTING: Between March 2001 and July 2002, 315 patients with creatinine clearance less than 60 mL/min (1.00 mL/s) at 28 centers in the United States were randomized to receive fenoldopam mesylate (n = 157) or placebo (n = 158). INTERVENTIONS: Patients were hydrated and randomized to receive intravenous fenoldopam (0.05 microg/kg/min titrated to 0.10 microg/kg/min) vs matching placebo, starting 1 hour prior to angiography and continuing for 12 hours. MAIN OUTCOME MEASURE: Contrast-induced nephropathy, defined as an increase of 25% or more in serum creatinine level within 96 hours postprocedure. RESULTS: Mean (SD) patient age was 70 (11) years, and 49% had diabetes mellitus. Mean (SD) baseline creatinine clearance was 29.0 (10.0) mL/min (0.48 [0.16] mL/s) (range, 7.5-56.8 mL/min [0.12-0.94 mL/s]), and 157 (108) mL of contrast was administered during the procedures. The primary end point of contrast-induced nephropathy occurred in 33.6% of patients assigned to receive fenoldopam vs 30.1% assigned to receive placebo (relative risk, 1.11; 95% confidence interval, 0.79-1.57; P =.61). There were no significant differences in the 30-day rates of death (2.0% vs 3.8%, P =.50), dialysis (2.6% vs 1.9%, P =.72), or rehospitalization (17.6% vs 19.9%, P =.66) in fenoldopam vs placebo randomized patients, respectively. CONCLUSION: The selective dopamine-1 agonist fenoldopam mesylate does not prevent further renal function deterioration after contrast administration in patients with chronic renal insufficiency.

Adult↗
PubMed2003

Trained and supervised physician assistants can safely perform diagnostic cardiac catheterization with coronary angiography.

Using a prospectively collected database of patients undergoing cardiac catheterization, we sought to compare the outcomes of procedures performed by supervised physician assistants (PAs) with those performed by supervised cardiology fellows-in-training. Outcome measures included procedural length, fluoroscopy use, volume of contrast media, and complications including myocardial infarction, stroke, arrhythmia requiring defibrillation or pacemaker placement, pulmonary edema requiring intubation, and vascular complications. Class 3 and 4 congestive heart failure was more common in patients who underwent procedures by fellows compared with those undergoing procedures by PAs (P = 0.001). PA cases tended to be slightly faster (P = 0.05) with less fluoroscopic time (P < 0.001). The incidence of major complications within 24 hr of the procedure was similar between the two groups (0.54% in PA cases and 0.58% in fellow cases). Under the supervision of experienced attending cardiologists, trained PAs can perform diagnostic cardiac catheterization, including coronary angiography, with complication rates similar to those of cardiology fellows-in-training.

Aged↗
PubMed2003

C-reactive protein elevation independently influences the procedural success of percutaneous balloon mitral valve commissurotomy.

BACKGROUND: Markers of systemic inflammation including C-reactive protein (CRP) appear to predict morbidity and mortality in various clinical conditions. The presence of systemic inflammation and its impact on the procedural success of percutaneous balloon mitral valve commissurotomy (PBMC) in patients with rheumatic mitral stenosis has not been previously demonstrated. METHODS: Measurements of CRP with a high-sensitivity assay were performed at the time of PBMC or during post-procedural follow-up in 119 patients with mitral stenosis of rheumatic morphology. Patients were questioned to exclude confounders of CRP elevation and categorized into undetectable (< or =0.10 mg/L) and detectable (>0.10 mg/L) CRP levels. Detectable levels were further classified into assay range (>0.10 and < or =6.0 mg/L) and elevated (>6.0 mg/L). RESULTS: CRP was detectable in 76% of patients and elevated (>6.0 mg/L) in 36% of patients studied. Procedural success occurred in 89% of patients with undetectable CRP, as compared with only 67% in patients with detectable CRP (P =.028). This effect remained after controlling for age and valve score (previously described predictors of PBMC success). CONCLUSIONS: Systemic inflammation is common in patients with rheumatic mitral valve stenosis, and the relationship between procedural success and CRP suggests persistent inflammation may affect the results of PBMC.

Aged↗
PubMed2003

Contrast nephropathy : an evidence-based approach to prevention.

Contrast-induced nephropathy occurs in 2-10% of patients exposed to intravascular radiographic contrast agents and results in significant morbidity and mortality. Although the exact mechanism of this disorder has not been fully elucidated, contrast nephropathy is probably due to a combination of decreased renal medullary blood flow, resulting in medullary ischemia, and direct toxicity to renal tubules. Contrast nephropathy is most commonly defined as either a >25% increase or a >0.5 mg/dL rise in serum creatinine level within 48 hours of contrast medium exposure. Baseline characteristics associated with an increased risk for development of contrast nephropathy include the presence of baseline renal dysfunction, diabetes mellitus, congestive heart failure, volume depletion, and concomitant administration of nephrotoxic drugs. Many strategies have been investigated in an effort to prevent the occurrence of renal dysfunction following contrast media exposure. Intravenous hydration has been shown to significantly decrease the incidence of nephropathy in high-risk patients. However, trials of several prophylactic pharmacologic interventions have been mostly disappointing, including the administration of calcium channel antagonists, diuretics, dopamine, endothelin receptor antagonists and fenoldopam. The use of N-acetylcysteine has been shown in some trials to decrease the incidence of contrast nephropathy in patients with a baseline renal dysfunction, and should currently be strongly considered in this high-risk patient subgroup in addition to hydration. Our purpose is to review the contemporary literature regarding contrast-induced renal dysfunction and present an evidence-based approach for prevention of this complication.

Acute Kidney Injury↗
PubMed2003

Exercise echocardiographic comparison of pulmonary autograft and aortic homograft replacements for aortic valve disease in adults.

BACKGROUND AND AIM OF THE STUDY: The pulmonary autograft, or Ross procedure, has theoretical hemodynamic benefits over other aortic valve replacements. The hemodynamic performance of the pulmonary autograft and pulmonary homograft components of this procedure have not been well defined. METHODS: Twenty patients with pulmonary autograft replacement of the aortic valve and six with aortic homografts underwent exercise echocardiography with assessment of exercise duration, left ventricular dimensions, mass, and function. Hemodynamics at rest and maximal exercise, including Doppler gradients and effective orifice area (EOA), were measured across the pulmonary autograft and aortic homograft valves. Doppler gradients across the pulmonary homograft valves were compared to native pulmonary valve gradients at rest and maximal exercise. RESULTS: Both groups of patients had excellent self-reported and measured exercise capacity. In comparison to the aortic homograft, the pulmonary autograft had lower peak Doppler gradients across the neoaortic valve at rest (5 +/- 2 versus 11 +/- 4 mmHg; p = 0.027) and maximal exercise (10 +/- 5 versus 15 +/- 5 mmHg; p = 0.003) and larger indexed EOA. However, the Ross procedure patients had higher gradients across the pulmonary homograft both at rest (14 +/- 10 versus 3 +/- 1 mmHg; p < 0.001) and maximal exercise (25 +/- 22 versus 5 +/- 4 mmHg; p = 0.004). Two patients in the Ross procedure group had significant pulmonary homograft stenosis in short- or mid-term follow up. CONCLUSION: In comparison to aortic homograft replacement of the aortic valve, pulmonary autograft replacement has superior hemodynamics at rest and during exercise. However, the pulmonary homograft replacement may develop hemodynamically significant stenosis after the Ross procedure.

Adult↗
PubMed2002

Serial echocardiographic evaluation of restenosis after successful percutaneous mitral commissurotomy.

OBJECTIVES: This study was designed to determine predictors of restenosis after successful percutaneous mitral commissurotomy (PMC) and its relationship to late clinical outcome. BACKGROUND: The restenosis rate after PMC and its relationship to late clinical outcome is poorly defined. METHODS: Serial echocardiography was performed in 310 patients who underwent PMC. Restenosis, defined as mitral valve area (MVA) <1.5 cm(2) and > or = 50% loss of initial MVA increase, was determined by both two-dimensional (2D) and Doppler echocardiography. Clinical, echocardiographic and cardiac catheterization variables were evaluated to determine predictors of restenosis. The relationship between restenosis and major adverse clinical events (death, repeat PMC or mitral valve replacement) and functional status was assessed. RESULTS: Acute procedural success occurred in 206 patients (66%), who were then followed for restenosis. The cumulative restenosis rate was approximately 40% at six years after successful PMC (44% by 2D and 40% by Doppler MVA). The only independent predictor of restenosis was echocardiographic score (restenosis at five years was 20% for score <8 vs. 61% for score > or = 8, p < 0.001). The decline in MVA and occurrence of restenosis was gradual and progressive during the follow-up period. Procedural results and baseline factors predicted event-free survival. Restenosis by 2D MVA was related to adverse events or New York Heart Association functional class 3 to 4 symptoms, but restenosis was not an independent predictor of clinical outcome by multivariate analysis. CONCLUSIONS: Restenosis is a common, gradual and progressive occurrence after successful PMC and is predicted by higher echocardiographic score. Restenosis is related to late adverse clinical outcome, though clinical outcome remains best predicted by the acute procedural results of PMC.

Aged↗
PubMed2002

Association of novel polymorphisms with the expression of SPARC in normal fibroblasts and with susceptibility to scleroderma.

OBJECTIVE: Fibroblasts from patients with systemic sclerosis (SSc) have an activated phenotype characterized by increased synthesis of extracellular matrix (ECM) components. SPARC (secreted protein, acidic and rich in cysteine) regulates the deposition or assembly of ECM components. The aim of this study was to investigate the role of SPARC in SSc susceptibility by functional and genetic association studies. METHODS: Complementary DNA (cDNA) microarrays were used to obtain gene expression data on cultured dermal fibroblasts from SSc patients. SPARC protein levels were assessed by Western blotting. Five polymorphic microsatellite markers within 5 cM of the SPARC gene (chromosome 5q31-32) were genotyped in Choctaw Indians, a population previously shown to have a high prevalence of SSc. Discovery of single-nucleotide polymorphisms (SNPs) was accomplished by sequencing the SPARC cDNA. These SNPs were then genotyped in a multi-ethnic cohort of SSc patients to determine potential associations with disease susceptibility in a broader population of SSc patients, as well as with various clinical and immunologic features of SSc. The functional relevance of these SNPs with regard to transcript stability of SPARC was also assessed. RESULTS: Microarrays demonstrated increased expression of SPARC, along with other ECM genes, in SSc patients compared with normal controls. SSc fibroblasts also had increased SPARC protein levels. Three of 5 microsatellite markers near SPARC showed significant associations with SSc in the Choctaw SSc patients. Sequencing of SPARC cDNA revealed 3 novel SNPs in the 3'-untranslated region at +998 (C-->G), +1551 (C-->G), and +1922 (T-->G). Homozygosity for the C allele at SNP +998 was significantly increased in SSc patients across ethnic lines. SPARC SNPs +1551 and +1922 demonstrated correlations with Raynaud's phenomenon and pulmonary fibrosis, respectively. Functional studies of SPARC SNP +998 in normal fibroblast cultures suggested a correlation between the SNP +998 C allele polymorphism and an increased messenger RNA half-life. CONCLUSION: This study is the first to show that polymorphisms of the SPARC gene are associated with susceptibility to, and clinical manifestations of, SSc and that they may also be functionally important in influencing SPARC expression in skin fibroblasts.

Blotting, Western↗