heart.valve: Aortic valve replacement surgery data from the 'joineR'...
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A longitudinal data on detecting the effects of different heart valves, differing on type of tissue, implanted in the aortic position. The data consists of longitudinal measurements (three cardiac functions) from patients who underwent aortic valve replacement from 1991 to 2001 at the Royal Brompton Hospital, London, United Kingdom. The data was first reported in [1] where the authors used all patients during the 10 years period with at least a year of follow up with serial echocardiographic measurements and applied a linear mixed-effect model to predict left ventricular mass index (LVMI). Similarly, the data was used in [2] to predict longitudinal profile of LVMI categorized as high or normal using several patient baseline characteristics and laboratory variables. LVMI is considered increased if LVMI >134 g/m 2 in male patients and LVMI >110 g/m 2 in female patients, thus values in this range for both sex was considered as the positive class in MEml.

1	data(heart.valve)

This is a data frame in the unbalanced format, that is, with one row per observation. The data consists in columns for patient identification, time of measurements, longitudinal multiple longitudinal measurements, baseline covariates, and survival data. The column names are identified as follows:

num: number for patient identification.
sex: gender of patient (0 = Male and 1 =Female).
age: age of patient at day of surgery (years).
time: observed time point, with surgery date as the time origin (years).
fuyrs: maximum follow up time, with surgery date as the time origin (years).
status: censoring indicator (1 = died and 0 =lost at follow up).
grad: valve gradient at follow-up visit.
log.grad: natural log transformation of grad.
lvmi: left ventricular mass index (standardised) at follow-up visit.
log.lvmi: natural log transformation of lvmi.
ef: ejection fraction at follow-up visit.
bsa: preoperative body surface area.
lvh: preoperative left ventricular hypertrophy.
prenyha: preoperative New York Heart Association (NYHA) classification (1 = I/II and 3 = III/IV).
redo: previous cardiac surgery.
size: size of the valve (millimeters).
con.cabg: concomitant coronary artery bypass graft.
creat: preoperative serum creatinine (μmol/mL).
dm: preoperative diabetes.
acei: preoperative use of ace inhibitor.
lv: preoperative left ventricular ejection fraction (LVEF) (1 = good, 2 = moderate, and 3 = poor).
emergenc: operative urgency (0 = elective, 1 =urgent, and 3 = emergency).
hc: preoperative high cholesterol (0 = absent, 1 =present treated, and 2 = present untreated).
sten.reg.mix: aortic valve haemodynamics (1 = stenosis, 2 = regurgitation, 3 = mixed).
hs: implanted aortic prosthesis type (1 = homograft and 0 = stentless porcine tissue).
inc.lvmi: increase in LVMI. (1= if LVMI >134 g/m 2 in male patients and LVMI >110 g/m 2 in female patients, 0=Otherwise

Mr Eric Lim (http://www.drericlim.com)

Lim E, Ali A, Theodorou P, Sousa I, Ashrafian H, Chamageorgakis T, Duncan M, Diggle P, Pepper J. A longitudinal study of the profile and predictors of left ventricular mass regression after stentless aortic valve replacement. Ann Thorac Surg. 2008; 85(6): 2026-2029. Che Ngufor, Holly Van Houten, Brian S. Caffo , Nilay D. Shah, Rozalina G. McCoy Mixed Effect Machine Learning: a framework for predicting longitudinal change in hemoglobin A1c, in Journal of Biomedical Informatics, 2018

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nguforche/Vira documentation built on June 2, 2019, 9:08 p.m.