CORONARY ARTERY CALCIFICATION

A PREDICTOR OF SEVERITY OF CORONARY ARTERY DISEASE, BASED ON 64- SLICE CORONARY COMPUTED TOMOGRAPHY ANGIOGRAPHY

Abstract

Background: Due to increased risk of CAD and cardiovascular events,
prediction of severity and/ or complexity of coronary artery disease (CAD) are valuable.
Previously association between severity of CAD and total coronary artery calcium (CAC) score
was not demonstrated but now there are lot of studies which have proven this association
but still association between total CAC score and complexity of CAD is not well established.
Objective: This study was conducted: (1) To investigate the association between coronary
artery calcium (CAC) score and CAD assessed by CCTA. (2) To find which one of the two, CAD
severity or complexity, is better associated with total CAC score in symptomatic patients having
significant CAD. Study Design: Observational cross sectional study. Place and Duration: The
study was conducted at Shifa International Hospital Faisalabad from March 2013 to June 2016.
Materials and Methods: Total 195 consecutive patients of both gender age ≥20 years who
was referred for CT angiography to our hospital and who fulfill the inclusion and exclusion
criteria was included in the study. Before enrollment in the study all patients gave informed
consent. Before CT angiography total CAC score was obtained by non- enhanced CT scans.
Demographic characteristics of all patients were obtained. Regarding risk factors for CAD,
history of hypertension, diabetes mellitus, family H/O ischemic heart disease and hyperlipidemia
was noted. In all patients before CT angiography, Lab. investigations including complete blood
count, fasting blood sugar, fasting lipid profile, blood urea and serum creatinine levels were
obtained. Calcium scores were quantified by the scoring algorithm proposed by Agatston et al.
All lesions were added to calculate the total CAC score by the Agatston method. Calcium scores
were divided into the following categories: 0, 1–100, 101–400, and ≥400. The degree of stenosis
was classified into four categories: (1) no stenosis, (2) minimal or mild stenosis (≤50%), (3)
moderate stenosis (50%–70%), and (4) severe stenosis (>70%). CAD was defined when lumen
diameter reduction was greater than 50% (moderate or severe stenosis). Results: Total 195
patients were studied. 136 (69.7%) were male and 59 (30.3%) were female. Mean age of study
population was 52.8±10.38 years. 81(41.54%) patients had H/O chest pain, 11(5.64%) had
H/O shortness of breath and 96(49.23%) presented with chest tightness. 104(53.33%) patients
were hypertensive, 71(36.41%) were diabetic, 67(34.35%) had increased cholesterol level. In
57 (29.2%) there was no coronary artery disease, 58(29.7%) had mild CAD, 32 (16.4%) had
moderate and 48 (24.6%) had severe coronary artery disease on CT angiography. Single vessel
was involved in 38(19.5%) patients, 20(10.3%) had two vessel disease and triple vessel disease
was present in 22(11.3%) patients. 104(53.3%) patients had zero calcium score. 44(22.6%)
had CAC score between 1-100, 37 (19%) had CAC score between 101-400 and more than 400
CAC score was documented in 10 (5.1%) patients. Conclusions: This study in addition to
patient based analysis also confirms the significant relationship between vessels based CAD
and CAC score. The prevalence of multivessel CAD increased in patients with CACS >100 and
there is 100% incidence of CAD in patients with CACS >1000. Zero calcium cannot exclude the
presence of significant CAD. Our data supports that in symptomatic patients calcium scoring is
an additional filter before coronary angiography.