Cardiac events after five years of a normal perfusion myocardial scintigraphy

Abstract

Aim: N-terminal proBNP peptide (NTproBNP) is a valuable tool in the diagnosis of heart failure and has a prognostic value in CAD patients (pts). Parameters derived from gated SPECT and kidney function have however also a strong prognostic value in these pts. Our study aim was to assess whether gated SPECT data and kidney function are independent determinants of NTproBNP in CAD pts above 65 years. Methods: We studied 131 consecutive pts with stable CAD referred for myocardial perfusion imaging. Left ventricular (LV) volumes were derived from myocardial gated SPECT data. Summed stress, rest and difference scores were calculated using semi-quantitative 4DM SPECT software (Michigan U.). Glomerular filtration rate (GFR) was calculated with a validated equation based on serum creatinine level.Univariate clinical and SPECT determinants of NTproBNP were investigated using ANOVA. A linear regression model was used to determine independent predictors of log NTproBNP. Results: The study population consisted of 131 pts (79 males, mean age 71Ϯ6 y). Univariate predictors of a higher NTproBNP were a lower GFR (pϽ.001), a longer QRS duration (pϭ .008), higher resting & post-stress end-diastolic and end-systolic (ESV) volumes (all pϽ.001)and a a higher summed stress and rest score (both pϽ .001). GFR (F changeϭ 44.4; pϽ .001) and post stress LV ESV (F changeϭ 31.5; pϽ.001) were the only independent determinants of log NTproBNP in the regression analysis. In the figure mean log NTproBNP values in these pts are shown according to a low versus high GFR (divided on the median) and post stress LVESV (divided in tertiles).Background: early detection of coronary atherosclerotic disease (CAD) is important to prevent death and disability. Myocardial perfusion scintigraphy (MPS) has the appropriate diagnostic and prognostic applications for patients who have an intermediate or high likelihood of disease, but it may not be cost-effective and should be performed only when reasonable doubt is left from other less sophisticated approaches. Based on clinical-epidemiological (CE) probability algorithms of CAD, patients classified as low likelihood of disease might either have no testing or simply undergo exercise testing (EXT). If the EXT results negative the patient is simply followed up; if the EXT is positive, the nuclear test is appropriate. Although this information is useful, it has some problems when in clinical practice. The challenges are how to adequately define patients in terms of likelihood of disease and how to integrate the pre-test probability with EXT results. Objective: to create and evaluate a logistic regression equation to classify patients to be referred to MPS based on the analysis of CE and EXT data. Methods: CE and EXT data on 2099 patients who had MPS performed in a nuclear medicine laboratory from 06/2000 to 06/2003 were collected for analysis. None of these patients had previous history of CAD. Each one was classified by utilizing a modified CE score based on the Framingham study database and EXT information derived f...