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Biomedical subjects

Nelson B Schiller

Publications and source records attributed to Nelson B Schiller.

At least 19 recordsLinked to original sources
PubMed2007

N-terminal fragment of the prohormone brain-type natriuretic peptide (NT-proBNP), cardiovascular events, and mortality in patients with stable coronary heart disease.

CONTEXT: Identification of individuals at high risk for cardiovascular events is important for the optimal use of primary and secondary prevention measures. OBJECTIVE: To determine whether plasma levels of amino terminal fragment of the prohormone brain-type natriuretic peptide (NT-proBNP) predict cardiovascular events or death independent of other available prognostic tests. DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort study (2000-2002) of 987 individuals in California with stable coronary heart disease in the Heart and Soul Study, who were followed up for a mean of 3.7 (range, 0.1-5.3) years. MAIN OUTCOME MEASURES: The association of baseline NT-proBNP levels with death or cardiovascular events (myocardial infarction, stroke, or heart failure). Traditional clinical risk factors, echocardiographic measures, ischemia, other biomarkers, and New York Heart Association classification were adjusted for to determine whether NT-proBNP levels were independent of other prognostic factors. Receiver operating characteristic (ROC) curves were used to assess the incremental prognostic value of adding NT-proBNP level to these other measures. RESULTS: A total of 256 participants (26.2%) had a cardiovascular event or died. Each increasing quartile of NT-proBNP level (range of quartile 1, 8.06-73.95 pg/mL; quartile 2, 74-174.5 pg/mL; quartile 3, 175.1-459 pg/mL; quartile 4, > or =460 pg/mL) was associated with a greater risk of cardiovascular events or death, ranging from 23 of 247 (annual event rate, 2.6%) in the lowest quartile to 134 of 246 (annual event rate, 19.6%) in the highest quartile (unadjusted hazard ratio [HR] for quartile 4 vs quartile 1, 7.8; 95% confidence interval [CI], 5.0-12.1; P<.001). Each SD increase in log NT-proBNP level (1.3 pg/mL) was associated with a 2.3-fold increased rate of adverse cardiovascular outcomes (unadjusted HR, 2.3; 95% CI, 2.0-2.6; P<.001), and this association persisted after adjustment for all of the other prognostic measures (adjusted HR, 1.7; 95% CI, 1.3-2.2; P<.001). The addition of NT-proBNP level to standard clinical assessment and complete echocardiographic parameters significantly improved the area under the ROC curves for predicting subsequent adverse cardiovascular outcomes (0.80 for clinical risk factors and echocardiographic parameters plus log NT-proBNP vs 0.76 for clinical risk factors and echocardiographic parameters only; P = .006). CONCLUSIONS: Elevated levels of NT-proBNP predict cardiovascular morbidity and mortality, independent of other prognostic markers, and identify at-risk individuals even in the absence of systolic or diastolic dysfunction by echocardiography. Level of NT-proBNP may help guide risk stratification of high-risk individuals, such as those with coronary heart disease.

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PubMed2006

Elevated pulmonary artery pressure by Doppler echocardiography predicts hospitalization for heart failure and mortality in ambulatory stable coronary artery disease: the Heart and Soul Study.

OBJECTIVES: We compared the predictive ability of tricuspid regurgitation (TR) and end-diastolic pulmonary regurgitation (EDPR) gradients in outpatients with coronary artery disease. BACKGROUND: The TR and EDPR gradients, in conjunction with right atrial pressure, provide Doppler estimates of pulmonary artery systolic and diastolic pressures. We hypothesized that increases in TR or EDPR gradients in stable coronary artery disease would predict heart failure (HF) hospitalization or cardiovascular (CV) death. METHODS: We measured TR and EDPR gradients in 717 adults with completed outcome adjudications who were recruited for the Heart and Soul Study. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for HF hospitalization, CV death, all-cause death, and the combined end point. Multivariate adjustments were made for age, gender, race, history of CV or pulmonary disease, functional class, and left ventricular ejection fraction. RESULTS: There were 63 HF hospitalizations, 19 CV deaths, and 86 all-cause deaths at the 3-year follow-up. There were 466 measurable EDPR gradients and 573 measurable TR gradients. Age-adjusted ORs for EDPR >5 mm Hg predicted HF hospitalization (2.7, 95% CI 1.3 to 5.5, p = 0.006), all-cause death (2.5, 95% CI 1.4 to 4.4, p = 0.002), and HF hospitalization or CV death (2.7, 95% CI 1.4 to 5.2, p = 0.004). Age-adjusted OR for TR >30 mm Hg predicted HF hospitalization (3.4, 95% CI 1.9 to 6.2, p < 0.0001) and HF hospitalization or CV death (3.0, 95% CI 1.7 to 5.3, p = 0.0001). Multivariate adjusted OR per 5-mm Hg incremental increases in EDPR predicted HF hospitalization or CV death (1.9, 95% CI 1.01 to 3.6, p = 0.046) and all-cause death (1.7, 95% CI 1.05 to 2.8, p = 0.03). Multivariate adjusted OR per 10-mm Hg incremental increases in TR predicted HF hospitalization or CV death (1.6, 95% CI 1.1 to 2.4, p = 0.008). CONCLUSIONS: Increases in EDPR or TR gradients predict HF hospitalization or CV death among ambulatory adults with coronary artery disease.

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PubMed2006

Cystatin C, left ventricular hypertrophy, and diastolic dysfunction: data from the Heart and Soul Study.

BACKGROUND: Impaired kidney function, as measured by serum cystatin C, is associated with risk of incident heart failure. Whether cystatin C is associated with preclinical cardiac structural abnormalities is unknown. We evaluate whether cystatin C is associated with left ventricular hypertrophy, diastolic dysfunction, and systolic dysfunction among 818 outpatients with coronary artery disease who were free of clinical heart failure. METHODS AND RESULTS: The 818 study participants were categorized into quartiles based on serum cystatin C concentrations, with < or =0.91 mg/L constituting the lowest quartile (I) and > or =1.28 mg/L constituting the highest (IV). Left ventricular hypertrophy (left ventricular mass index >90 g/m(2) by truncated ellipsoid method), diastolic dysfunction (impaired relaxation, pseudo-normal, or restrictive filling patterns) and systolic dysfunction (left ventricular ejection fraction < or =50%) were determined by echocardiography. Left ventricular hypertrophy was present in 68% of participants in quartile IV, compared with 44% of those in quartile I (adjusted odds ratio [OR] 2.17; 95% confidence interval [CI] 1.34 to 3.52; P = .002). Diastolic dysfunction was present in 52% of participants in quartile IV, compared with 24% of those in quartile I (adjusted OR 1.79; 95% CI 1.04 to 3.11; P = .04). Systolic dysfunction was present in 12% of those in quartile IV, compared with 6% of those in quartile I (adjusted OR 1.83; 95% CI 0.75 to 4.46; P = .15). CONCLUSION: Higher cystatin C concentrations are strongly associated with left ventricular hypertrophy and diastolic dysfunction in outpatients with coronary artery disease and without heart failure.

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PubMed2006

Pulmonary hemodynamic effects of dipyridamole infusion in patients with normal and elevated pulmonary artery systolic pressure receiving PB127.

BACKGROUND: Intravenous administration of microspheres used as ultrasound contrast agents may potentially alter pulmonary hemodynamics. PB127 (POINT Biomedical Corp., San Carlos, CA) is an investigational ultrasound perfusion-imaging agent used in conjunction with dipyridamole to diagnose coronary artery disease. The effects of PB127 alone or in combination with dipyridamole on pulmonary hemodynamics have not been described. METHODS: We studied 20 patients, including 10 with elevated screening pulmonary artery systolic pressure (>35 mm Hg). Doppler-derived pulmonary hemodynamics were determined before and after continuous infusion of PB127 (0.175 mg/kg diluted in 5% dextrose) or 5% dextrose. Patients then received dipyridamole (0.56 mg/kg) and hemodynamics were again assessed. RESULTS: During PB127/dextrose infusion, there were no significant changes in pulmonary hemodynamics compared with baseline. After dipyridamole, there were small increases in pulmonary artery systolic pressure and in pulmonary flow and a reduction in pulmonary vascular resistance. These changes occurred in patients with normal and elevated pulmonary artery systolic pressure. CONCLUSION: PB127 infusion does not alter pulmonary hemodynamics. Mild alterations of pulmonary hemodynamics occur after dipyridamole administration.

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PubMed2006

Left atrial size is a poor predictor of pathology in the older patient: preliminary observations.

OBJECTIVE: The goal of this study was to determine the relationship between left atrial (LA) size and pathology in humans. METHODS: We evaluated 14 patients (age 60 +/- 14 years, range 25-77, 9 males) who had died at our hospital. Eight patients were in sinus rhythm, 3 had paroxysmal atrial fibrillation (PAF), and 3 were in established atrial fibrillation (AF). LA size was calculated at transthoracic echocardiography (TTE) prior to death. At autopsy, histology of the dissected LA was examined at the appendage (APP), transverse sinus (TS), oblique sinus (OS), crux, and oval fossa. The severity of hypertrophy (HTY) and fibrosis (FIB) was determined by histochemistry. RESULTS: Mean LA weight was 37 +/- 11 g. One patient with PAF had amyloid. LA size by TTE was associated with LA weight (R = 0.6, P = 0.029). Increased age was associated with less severe APP FIB (P = 0.04). Younger patients tended to have less severe APP HTY (P = 0.09), and TS FIB (P = 0.12). Severity of atrial HTY and FIB was similar in APP and TS (P = NS). There was no relationship between abnormal atrial histology with LA volume or cardiac rhythm. Five patients had LA dilatation (LA end systolic volume index >30 ml/m(2)). Of those patients with normal LA size, 6 (75%) had APP FIB, 8 (100%) had APP HTY, 7 (88%) had TS FIB, 8 (100%) had TS HTY, and 7 (88%) had OS HTY. CONCLUSIONS: Abnormal LA histology is common in patients who have normal LA size by TTE. Microscopic atrial disease is associated with aging, and may represent a precursor state for LA dilatation or AF.

Age Factors↗
PubMed2005

Association of metabolic syndrome with exercise capacity and heart rate recovery in patients with coronary heart disease in the heart and soul study.

It is not known whether the metabolic syndrome is associated with poor exercise capacity among patients who have established coronary heart disease. We evaluated the association of the metabolic syndrome with treadmill exercise capacity and heart rate recovery among patients who had coronary heart disease. We measured treadmill exercise capacity (METs) and heart rate recovery (beats per minute) in 943 subjects who had known coronary heart disease. Of these, 377 (40%) had the metabolic syndrome as defined by criteria of the National Cholesterol Education Program. Participants who had the metabolic syndrome were more likely to have poor exercise capacity (METs <5, 33% vs 18%, p <0.0001) and poor heart rate recovery (<or=16 beats/min, 34% vs 21%, p <0.0001) than those who did not have the metabolic syndrome. In ordinal logistic regression analyses, the metabolic syndrome was associated with decreased exercise capacity (odds ratio [OR] 2.2, 95% confidence interval [CI] 1.7 to 2.8, p <0.0001) and decreased heart rate recovery (OR 1.8, 95% CI 1.4 to 2.3, p <0.0001). These associations remained strong after adjusting for potential confounding variables (OR 1.6, 95% CI 1.2 to 2.1, p = 0.003 for decreased exercise capacity; OR 1.4, 95% CI 1.1 to 1.9, p = 0.02 for decreased heart rate recovery). The metabolic syndrome is independently associated with poor exercise capacity and poor heart rate recovery in patients who have established coronary heart disease. Decreased exercise capacity may contribute to the adverse outcomes associated with the metabolic syndrome.

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PubMed2005

Association of anemia with diastolic dysfunction among patients with coronary artery disease in the Heart and Soul Study.

We performed a cross-sectional study to evaluate the association of anemia with diastolic dysfunction and left ventricular hypertrophy (LVH) in outpatients who had coronary artery disease. Logistic regression was used to examine the association of blood hemoglobin (Hb) concentrations with diastolic dysfunction and LVH in 822 participants in the Heart and Soul Study who had normal sinus rhythm and preserved systolic function (left ventricular ejection fraction >/=50%). Using transthoracic echocardiography, diastolic dysfunction was defined as diastolically dominant pulmonary vein flow, and LVH was defined as left ventricular mass index >90 g/m(2). Anemia (Hb <13 g/dl) was present in 24% of participants (197 of 822). The prevalence of diastolic dysfunction ranged from 8% in participants who did not have anemia (Hb >/=13 g/dl) to 13% in those who had moderate anemia (Hb 11 to 13 g/dl) to 24% in those who had severe anemia (Hb <11 g/dl, p = 0.004 for trend). After multivariable adjustment, moderate anemia (odds ratio [OR] 2.0, 95% confidence interval [CI] 1.1 to 3.6) and severe anemia (OR 6.6, 95% CI 1.9 to 24.9) remained strongly associated with diastolic dysfunction. In contrast, moderate anemia (OR 1.4, 95% CI 1.0 to 2.1) and severe anemia (OR 1.6, 95% CI 0.6 to 4.6) were not significantly associated with LVH. We found anemia to be strongly associated with diastolic dysfunction but not with LVH in this community-based sample of outpatients who had established coronary disease.

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PubMed2005

Pulmonary regurgitation end-diastolic gradient is a Doppler marker of cardiac status: data from the Heart and Soul Study.

BACKGROUND: Echocardiograms routinely sample pulmonary regurgitation signals from which it is possible to measure end diastolic gradients; these correlate with pulmonary artery diastolic pressures. METHODS: We performed echocardiograms in 741 ambulatory adults with coronary artery disease who were recruited for the Heart and Soul Study. We compared indicators of cardiac status among individuals with normal (0-5.0 mm Hg) and elevated (> 5.0 mm Hg) end diastolic pulmonary regurgitation (EDPR) gradients. RESULTS: Of the 481 participants with measurable EDPR gradients, 21% had elevated EDPR gradients (> 5.0 mm Hg). EDPR gradients > 5.0 mm Hg were associated with higher New York Heart Association functional class (P = .002), higher brain natriuretic peptide (P = .002), fewer metabolic equivalents achieved on treadmill testing (P < 0.001), and higher left ventricular mass (P < 0.001). The EDPR gradient > 5.0 mm Hg had a sensitivity of 25% (95% confidence interval 20-30%) and a specificity of 86% (80-91%) for detecting at least one of the following: systolic dysfunction, diastolic dysfunction, or abnormal wall motion score. The EDPR gradient > 5.0 mm HG was statistically equivalent to the tricuspid regurgitation (TR) gradient > 30 mm Hg in terms of diagnostic value (area under the receiver operating characteristic curve equaled 0.58 for each test). The EDPR gradient increased the yield of pulmonary artery pressures from 61% (TR gradient alone) to 84% (P < .0001). CONCLUSION: The EDPR gradient provides valuable information independent of the TR gradient in evaluating pulmonary artery pressures and cardiac dysfunction.

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PubMed2004

Is PA-PWRmax truly a preload-independent index of myocardial contractility in anesthetized humans?

This study tested the hypothesis that the preload-adjusted maximal power index (PA-PWRmax) is a load-independent index of human myocardial contractility. Based on the ventricular pressure-volume relationship and derived from stroke work, the index is the product of instantaneous ventricular pressure and volume changes, divided by a correction term of end-diastolic volume (EDV2) or end-diastolic area (EDA3/2) to adjust for preload effects. Echocardiographic measures of instantaneous ventricular area change may be used to obtain PA-PWRmax noninvasively. We prospectively evaluated 28 human subjects undergoing cardiac evacuation before cardiopulmonary bypass procedures. Continuous peripheral arterial pressure, pulmonary arterial pressure, and echocardiographic views of the left ventricle in the transgastric short-axis view were recorded. Simultaneously gated instantaneous fractional shortening (FS) and PA-PWRmax indices were calculated, with FS = (EDA - ESA)/EDA and PA-PWRmax = [MAP (EDA - ESA)]/ EDA3/2, where ESA = end-systolic area and MAP = instantaneous mean arterial pressure. FS decreased uniformly with cardiac evacuation and decreasing pulmonary artery diastolic pressure (t = -5.4; 95% confidence interval, -10 to -0.046; p < 0.001), as did PA-PWRmax (t = -5.8; 95% confidence interval, -2.25 to -1.08; p < 0.001). FS and PA-PWRmax showed a strong downward correlation (r = 0.81). Unlike previous studies of autonomically denervated animals, our study did not find PA-PWRmax to be preload independent, perhaps because of the instantaneous homeostatic mechanisms of the human autonomic nervous system linking contractility to loading conditions.

Anesthesia, General↗
PubMed2004

Is B-type natriuretic peptide a useful screening test for systolic or diastolic dysfunction in patients with coronary disease? Data from the Heart and Soul Study.

BACKGROUND: Whether B-type natriuretic peptide (BNP) levels can be used to screen for ventricular dysfunction in patients at risk of heart failure but without overt symptoms is not known. We examined the characteristics of a BNP test for identifying systolic and diastolic dysfunction in outpatients with stable coronary disease. METHODS: In a cross-sectional study of 293 outpatients who had stable coronary disease and no history of heart failure, we compared elevations in plasma BNP levels with echocardiography for the diagnosis of systolic dysfunction (ejection fraction <55%) and diastolic dysfunction (diastolic dominant pulmonary vein flow with ejection fraction > or =55%). RESULTS: A total of 48 patients (16%) had systolic dysfunction, and among the remaining 245 with preserved systolic function, 31 (13%) had diastolic dysfunction. At the standard cutpoint of >100 pg/mL, an elevated BNP level was 38% sensitive (80% specific) for systolic dysfunction and 55% sensitive (85% specific) for diastolic dysfunction. Negative likelihood ratios were 0.8 (95% confidence interval [CI]: 0.6 to 1.0) for systolic dysfunction and 0.5 (95% CI: 0.4 to 0.8) for diastolic dysfunction. Positive likelihood ratios were 1.9 (95% CI: 1.2 to 2.9) for systolic dysfunction and 3.8 (95% CI: 2.4 to 5.9) for diastolic dysfunction. Areas under the receiver operating characteristic curves were 0.59 (95% CI: 0.49 to 0.69) for systolic dysfunction and 0.79 (95% CI: 0.71 to 0.87) for diastolic dysfunction. CONCLUSION: These data suggest that BNP is not a useful screening test for asymptomatic ventricular dysfunction in patients with stable coronary disease.

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PubMed2004

Comparison of left atrial volume and function after linear ablation and after cardioversion for chronic atrial fibrillation.

Several techniques for treatment of atrial fibrillation (AF) have been developed, including the direct placement of radiofrequency for lesions at open heart surgery. Detailed evaluation of left atrial (LA) function has not been performed after these procedures and has not been compared in patients with chronic AF. We compared the atrial function of patients with sustained sinus rhythm (SR) after linear ablation with a group who underwent direct-current cardioversion and a group of normal controls to investigate the measurable deleterious effects, if any, on atrial function after the surgical procedure. Twenty-one consecutive patients who had maintained SR for >6 months after a linear radiofrequency ablation (LRFA) procedure were studied. As control subjects, we examined 33 patients with chronic AF successfully restored to SR by cardioversion who maintained SR for >6 months and 42 age-matched normal subjects. LA function was decreased in both the LRFA and cardioverted AF groups compared with normal controls. The parameters of LA function, atrial fraction, LA ejection fraction, and the A' velocity were lowest in the LRFA group, intermediate in the cardioverted AF group, and highest in the normal controls (LA function: 15.8 +/- 10%, 26 +/- 10%, 33 +/- 7%; p = 0.0001; LA ejection fraction: 31 +13%, 41 +/- 12%, 51 +/- 9%; p = 0.0001; A' velocity: 4.2 +/- 1.4, 7.6 +/- 2.2, 9.5 +/- 1.9 cm/s; p = 0.0001). LA volumes were increased in the LRFA and cardioverted AF groups compared with normals (62.8 +/- 22 vs 70.6 +/- 17 vs 38.7 +/- 9.8 ml; p = 0.0001). Thus, although LA function is restored and maintained after LRFA has been performed during open heart surgery, LRFA use is associated with a measurable decrease in LA function over and above that found after conventional cardioversion.

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PubMed2004

Noninvasive measurement of systemic vascular resistance using Doppler echocardiography.

BACKGROUND: Systemic vascular resistance (SVR) is an integral therapeutic component of patients with heart failure and shock. We hypothesized that the ratio of the peak mitral regurgitant velocity (MRV) (m/s) to left ventricular outflow time-velocity integral (TVI(LVOT)) (cm) by Doppler would provide a noninvasive correlate of SVR. METHODS: SVR was correlated to MRV/TVI(LVOT) in 33 patients undergoing right heart catheterization. Receiver operating characteristic curves were generated to determine the best-balanced sensitivity and specificity to identify SVR > 14 Wood units (WU) and <10 WU. RESULTS: MRV/TVI(LVOT) correlated well with SVR (r = 0.842, 95% confidence interval 0.7-0.92, P <.001, Y = 0.459 + 49.397*X). By receiver operating characteristics, MRV/TVI(LVOT) > 0.27 had a 70% sensitivity and a 77% specificity to identify SVR > 14 WU. MRV/TVI(LVOT) < 0.2 had a 92% sensitivity and a 88% specificity to identify SVR < 10 WU. CONCLUSION: Doppler echocardiography provides a reliable noninvasive assessment of SVR.

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PubMed2004

Impairment of left atrial function predicts post-operative atrial fibrillation after coronary artery bypass graft surgery.

AIMS: Despite the prevalence of atrial fibrillation (AF) occurring after cardiac surgery, its pathophysiology is incompletely understood. Specifically, whether left atrial (LA) structural remodelling occurs, contributing to a decrement in atrial function and AF has not been previously determined. This study sought to determine the relationship between LA function and post-operative AF. METHODS AND RESULTS: Three hundred patients undergoing elective coronary artery bypass graft surgery were monitored with intraoperative transoesophageal echocardiography to determine LA function and dimensions. Post-operative AF was monitored with continuous telemetry until hospital discharge. The relationship between clinical factors versus LA function and dimension was assessed using multi-variate logistic regression. By univariate analysis, patients who subsequently developed post-operative AF had a larger LA area and LA appendage area, and lower LA ejection fraction measured in the pre-bypass period compared to those without subsequent AF. By multivariable analysis, in addition to clinical data including age (odds ratio [OR] 1.11, 95% confidence interval [CI] 1.05-1.16, P<0.0001), body surface area (OR 13.31, 95% CI 1.87-94.5, P=0.0097) and white race, post-bypass atrial systolic function (atrial filling fraction 0.36, OR 2.51, 95% CI 1.03-6.13, P=0.04) and abnormal relaxation of the left ventricle (E duration 270 ms) (OR 2.89, 95% CI 1.34-6.24, P=0.0067) independently increased the risk of post-operative AF. CONCLUSION: These results demonstrate that some of the structural and functional changes in the atria common to chronic AF in the elderly population are also prevalent in surgical patients who develop post-operative AF, suggesting that post-operative and chronic AF may have similar pathophysiology.

Atrial Fibrillation↗
PubMed2003

B-type natriuretic peptide and ischemia in patients with stable coronary disease: data from the Heart and Soul study.

BACKGROUND: In patients with symptoms of heart failure, elevations in B-type natriuretic peptide (BNP) accurately identify ventricular dysfunction. However, BNP levels are not specific for ventricular dysfunction in patients who do not have overt symptoms of heart failure, suggesting that other cardiac processes such as myocardial ischemia may also cause elevations in BNP. METHODS AND RESULTS: To determine whether BNP elevations are associated with myocardial ischemia, we measured plasma BNP levels before performing exercise treadmill testing with stress echocardiography in outpatients with stable coronary disease. Of the 355 participants, 113 (32%) had inducible ischemia. Compared with participants in the lowest BNP quartile (0 to 16.4 pg/mL), those in the highest quartile of BNP (> or =105 pg/mL) had double the risk of inducible ischemia (adjusted relative risk, 2.0; 95% CI, 1.2 to 2.6; P=0.008). The relation between elevated BNP levels and inducible ischemia was especially evident in the 206 participants who had a history of myocardial infarction (adjusted relative risk, 2.6; 95% CI, 1.5 to 3.7, P=0.002) and was absent in those without a history of myocardial infarction (adjusted relative risk, 1.0; 95% CI, 0.3 to 2.2; P=0.9). This association between BNP levels and inducible ischemia remained strong after adjustment for measures of systolic and diastolic dysfunction. CONCLUSIONS: Elevated levels of BNP are independently associated with inducible ischemia among outpatients with stable coronary disease, particularly among those with a history of myocardial infarction. The observed association between BNP levels and ischemia may explain why tests for BNP are not specific for ventricular dysfunction among patients with coronary disease.

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