Download Impaired aortic distensibility predicts reduced coronary flow velocity

Impaired aortic distensibility predicts
reduced coronary flow velocity reserve
in patients with suspected
coronary artery disease
Attila Nemes, Miklós Csanády, Tamás Forster
University of Szeged, Medical Faculty,
2nd Department of Medicine and Cardiology Center
Introduction
• Coronary flow velocity reserve (CFR) and aortic stiffness are
functional characteristics of the arterial system
• Aortic stiffness / distensibility can be characterized by elastic
parameters calculated from cyclic changes of aortic
dimensions and blood pressures (as aortic elastic modulus)
Peterson LN et al. Circ Res 1960
• CFR is a valuable index for evaluation of microvascular
function in the absence of LAD stenosis and can be measured
by echocardiography
Iliceto S et al. Circulation 1991
Aortic stiffness
Aortic stiffness describes the elastic resistance that the aorta sets against its
distension.
The inverse of stiffness is compliance (distensibility), which describes the ease of
systolic aortic expansion.
Aortic stiffness increases when the intraluminal pressure is high or due to
physiologic (age, gender) or pathophysiologic conditions (vascular risk factors and
diseases)
In these conditions the aortic wall is characterized by
• fibrosis
• medial smooth muscle cell necrosis
• breaks in elastin fibers
• calcifications
• diffusion of macromolecules into the arterial wall.
Belz GG Cardiovasc Drug Ther 1995
Measurement of aortic elastic modulus [E(p)]
during TEE
Normal systolo-diastolic aortic
diameter change
Reduced - irregular systolo-diastolic
aortic diameter change
Aortic elastic modulus E(p) = (SBP-DBP)/[(DS-DD)/DD]
Peterson LN et al. Circ Res 1960
Coronary flow (velocity) reserve
• Severe flow limiting epicardial stenosis or microvascular
pathologic state of the coronary arterioles result in diminution
of CFR.
• Disturbance in microcirculation = impaired flow in arteriolar
resistance vessels and/or capillary system (↑ vascular
resistance)
Epicardial stenosis
Normal epicardial artery
4x
4x
1x
Arteriolar vasodilation
1x
Microvascular disease
4x
Arteriolar vasodilation
1x
Arteriolar vasodilation
Iliceto S et al. Circulation 1991
Coronary flow (velocity) reserve
(TEE, TTE)
CFR = Dmax / Drest
Iliceto S et al. Circulation 1991
Parameters affecting CFR
Micro- and macrovascular factors: Atherosclerosis (cardiovascular risk
factors, hypertension, older age etc.)
Extravascular compressive forces: Pathologic left ventricular hypertrophy
(hypertension, HCM, AS)
Metabolic factors: Diabetes mellitus, hypercholesterolaemia
Rheologic factors: policythaemia, macrogobulinaemia
Others: Tachycardia, increased contractility, insulin resistance, vegetative
neuropathy, caffein intake, smoking, „red wine”, aortic stiffness etc.
Nemes A et al. Can J Physiol Pharmacol 2007
Fukuda D et al. Heart 2006
Saito M et al. Heart 2008
Association between aortic stiffness
and coronary artery disease
• Aortic stiffening may lead to early pulse wave reflection causing an
increase of central SBP and a decrease of DBP with increase of PP.
• The elevation in SBP
- increases myocardial oxygen demand
- reduces EF
- increases ventricular overload inducing LVH.
• Myocardial blood supply depends largely on pressure throughout
diastole and the duration of diastole
• The contemporary decrease of DBP can compromise coronary
perfusion resulting in subepicardial ischaemia.
TEE evaluation of CFR and aortic stiffness
The usefulness of dipyridamole stress TEE was extensively investigated
for the simultaneous evaluation of CFR and aortic elastic properties:
… in patients with coronary artery disease
… post-LAD-PCI
Nemes A et al. Int J Cardiol 2004
Nemes A et al. Echocardiography 2010
… in patients with negative coronary angiograms
… and diabetes mellitus
Nemes A et al. Can J Cardiol 2007
… and hypertension
Nemes A et al. Heart Vessels 2007
… and hypercholesterolaemia
Nemes A et al. Int J CV Imaging 2007
… and different ages
Nemes A et al. Aging Clin Exp Res 2009
… and aortic valve stenosis
Nemes A et al. J Heart Valve Dis 2004
… in patients with aortic atherosclerosis
Nemes A et al. Int J CV Imaging 2004
Relationship between CFR
and aortic stiffness
• Significant correlations were found between simultaneously
evaluated CFR and aortic elastic properties in different patient
populations
• Reduction of CFR could be demonstrated in patients with
increased aortic stiffness
Nemes A et al. Can J Physiol Pharmacol 2007
• Aortic distensibility seemed to provide complementary prognostic
information over CFR only in patients without CAD and abnormal
CFR
Nemes A et al. Heart Vessels 2008
Aims
The present study was designed to test whether
impaired echocardiography-derived aortic distensibility
predicts reduced CFR in patients with suspected
coronary artery disease
Patients
• The present study consisted of 158 consecutive
patients with suspected coronary artery disease.
• Coronary angiography had been performed in 129
cases (82%).
• Subjects with significant valvular heart disease,
congenital or hypertrophic cardiomyopathy,
myocarditis, or pericarditis were excluded.
• Regarding to the literature, a CFR <2 was considered
abnormal.
Results
All patients
CFR >2
CFR <2
No. of patients
158
74 (47)
84 (53)
Age (years)
58.0 ± 10.0
56.5 ± 10.1
59.9 ± 9.3
Diabetes mellitus (%)
41 (26)
17 (23)
24 (29)
Hypertension (%)
109 (69)
51 (69)
58 (69)
Hypercholesterolaemia (%)
74 (47)
34 (46)
40 (48)
LV end-diastolic diameter (mm)
52.2 ± 8.3
49.2 ± 7.4
54.9 ± 8.1*
Interventricular septum (mm)
10.8 ± 2.2
10.8 ± 2.1
10.8 ± 2.3
LV posterior wall (mm)
10.5 ± 2.1
10.5 ± 2.1
10.5 ± 2.1
145.8 ± 58.4
131.7 ± 50.1
158.8 ± 62.8*
62.9 ± 9.9
65.1 ± 8.6
60.9 ± 10.6
CFR
2.11 ± 0.81
2.74 ± 0.76
1.56 ± 0.28*
mean AA grade
1.18 ± 0.79
1.02 ± 0.89
1.31 ± 0.68*
E(p) (mm Hg)
813 ± 549
723 ± 495
892 ± 584*
129 (82)
60 (81)
69 (82)
Normal epicardial coronaries
42 (33)
25 (42)
17 (25)
LAD stenosis
33 (26)
9 (15)
24 (35)*
Non-LAD stenosis
14 (11)
10 (17)
4 (6)
Multivessel disease
40 (31)
16 (27)
24 (35)
Echocardiography
LVMI (g/m2)
LV ejection fraction (%)
Ttansoesophageal echocardiography
Coronary angiography
Diagnostic accuracy of E(p) in predicting
impaired CFR
Conclusions
Prognostic impact of impaired E(p) for reduced
CFR and therefore microcirculatory
dysfunction could be demonstrated in patients
with suspected coronary artery disease .