Correlation Between Coronary Artery Disease Severity Detected by CT Coronary Angiography and Grade of Left Ventricular Diastolic Dysfunction Detected by Echocardiography

<b>Background:</b> Coronary artery disease (CAD) and left-ventricular (LV) diastolic dysfunction are leading drivers of morbidity and mortality. Clarifying how anatomical CAD burden relates to diastolic impairment may refine diagnosis and risk stratification. <b>Methods:</b> We conducted a cross-sectional analytical study of 200 adults with intermediate pretest probability of CAD who underwent both coronary CT angiography (CCTA) and transthoracic echocardiography (TTE) within ≤1 year. Coronary burden was quantified by Segment Involvement Score (SIS). Diastolic function was graded by contemporary echocardiographic guidelines. Patients were classified as obstructive (≥50% LM or ≥70% in other major epicardial arteries) or non-obstructive CAD. <b>Results:</b> Obstructive CAD was present in 73/200 (36.5%). Diastolic dysfunction occurred in 161/200 (80.5%) and was markedly more prevalent/severe in obstructive vs. non-obstructive CAD (<i>p</i> < 0.001). SIS rose stepwise with higher diastolic dysfunction grades; SIS correlated strongly with diastolic grade (r = 0.809, <i>p</i> < 0.001). Compared with non-obstructive CAD, obstructive CAD showed worse diastolic indices (higher E/e', larger LAVI, shorter DT and IVRT; all <i>p</i> < 0.001) and a shift toward Grades II-III. Obstructive CAD was also associated with higher total cholesterol, triglycerides, LDL, HbA1c, lower HDL (all <i>p</i> ≤ 0.002), and a greater prevalence of hypertension and diabetes. <b>Discussion:</b> Increasing coronary atherosclerotic burden-captured by SIS, parallels progressive impairment of LV relaxation and elevated filling pressures, supporting a pathophysiologic link between epicardial disease extent and diastolic dysfunction. <b>Conclusions</b>: In symptomatic intermediate-risk patients, greater CAD extent on CCTA is strongly associated with higher grades of LV diastolic dysfunction on echocardiography. Integrating anatomic (SIS) and functional (TTE) metrics may enhance risk assessment and guide management in CAD.