P1008Could aortic dysfunction explain angina in patients with angiographically normal coronary arteries?


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Abstract

Background: Angina with angiographically normal coronary arteries (NCA) still has controversial pathophysiological mechanisms. Experimental studies have shown that coronary artery blood flow varies with aortic (Ao) stiffness, but clinical data are poor.Objective: To assess Ao function by different echocardiographic techniques in patients (pts.) with angina and NCA versus asymptomatic pts. (with or without cardiovascular risk factors).Methods: Study group consisted of 15 pts. with angina and angiographically NCA (mean age 60,9 ± 5,3 years) and 15 age and gender- matched control subjects (asymptomatic pts), mean age 58,9 ± 8,6 years. Systemic hypertension was found in 66,7% of pts. with angina and NCA and in 60% of control group (p=NS). There were 2 subjects with type 2 diabetes mellitus in both pts. and control groups. 33,3 % of subjects were smokers in pts. group and 46,6% of control subjects (p=NS). Dyslipidemia was found in 53,3% of pts. with angina and NCA and 40 % of control group (p=NS).Methods: Ao stiffness indices, calculated using ascending Ao systolic and diastolic diameters were: Ao Strain, Ao distensibility (Ao Dis), Ao stiffness index (Ao SI).Ao function was evaluated also by measuring tissue Doppler (TdI) systolic (SW), early and late diastolic(EW, AW) velocities of the anterior Ao wall.Total afterload was defined by the effective arterial elastance (Ea=0.9Xsystolic blood pressure/SV, SV=stroke volume). Systemic vascular resistance index (SVRI)= mean arterial pressure/cardiac index. Total arterial compliance (Ca)=SV/pulse pressure.Results: Pts. with angina and NCA had decreased Ao strain and Ao dis and increased Ao stiffness compared with control subjects: Ao Strain 17,7±7,4 % vs 24,8 ± 10,8 % (p=0,05), Ao Dis 078 ±0,3 vs 1,2 ± 0,6cm2/dyne (p<0,05), Ao SI 3,4±1,8 vs 1,9 ±0,5 (p<0,05).SW and EW TdI Ao wall velocities were decreased in pts group versus control subjects : SW 6,7± 1,6 vs 10 ±1,9 cm/s, (p<0,05), EW 5,6 ±2,1 vs 9,4 ±2,7 cm/s (p<0,05), AW 7,1± 2,3 vs 7,7±2,9 cm/s (p=0,4).Ea and SVRI were increased and Ca decreased in pts with angina versus asymptomatic subjects: Ea 2,1± 0,5 vs 1,6 ±0,2 mmHg/ml (p<0,05), SVRI 2,9± 0,8 vs 1,9±0,2 dyne *s *m2/cm-5 (p<0,05), Ca 1,2 ± 0,4 vs 1,6 ±0,3 ml/mm Hg (p<0,05).Conclusion: Aortic vascular function, evaluated by multiple parameters, proved to be altered in patients with angina and normal coronary arteries versus control subjects. These findings suggest a possible pathophysiological link between aortic stiffening, increased afterload and angina symptoms, in the absence of coronary stenoses.

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