Abstract 2085: Increased Regional Coronary Vascular Resistance During Hyperemia in Hypertrophic Cardiomyopathy Is Associated with Reduced Myocardial Blood Volume

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Hiroshi Komatsu ◽  
Satoshi Yamada ◽  
Masanao Naya ◽  
Hisao Onozuka ◽  
Taisei Mikami ◽  
...  
Keyword(s):  
Hypertrophic Cardiomyopathy ◽  
Blood Volume ◽  
Vascular Resistance ◽  
Contrast Echocardiography ◽  
Interventricular Septum ◽  
Power Doppler ◽  
Doppler Imaging ◽  
Coronary Vascular Resistance ◽  
Coronary Resistance ◽  
Myocardial Blood Volume

Introduction: In patients with hypertrophic cardiomyopathy ( HCM ), myocardial blood flow ( MBF ) is decreased during hyperemia because of high coronary vascular resistance. Recently myocardial blood volume ( MBV ) can be estimated in vivo using myocardial contrast echocardiography ( MCE ) with the compensation for acoustic field inhomogeneity. The relationship between MBV and coronary resistance, however, has not been investigated. We thus assessed the hypothesis that increased regional coronary vascular resistance during hyperemia in HCM is associated with reduced MBV. Methods: In 13 patients with HCM ( H , 53±16 years) with asymmetric septal hypertrophy and 9 normal volunteers ( N , 54±11 years), MCE was performed under infusion of Levovist at rest and during hyperemia induced by ATP. Apical 4-chamber views of intermittent harmonic power Doppler imaging were acquired at end-diastole of every sixth beat. MBV was calculated as 10 X/10 ×100%, where X was myocardial contrast intensity minus contrast intensity of the adjacent intracavity blood pool in dB. 15 O-water PET was performed to measure regional MBF. These parameters were measured in the interventricular septum ( IVS ) and LV posterolateral ( PL ) wall. Regional coronary vascular resistance was calculated as (mean blood pressure)/MBF. Results: Wall thickness was significantly greater in H than in N (IVS: 19±4 vs 10±1 mm, p<0.0001; PL: 10±1 vs 9±1 mm, p<0.05). MBV of IVS was lower in H than in N (rest: 2.1±0.7 vs 3.5±1.1%, p<0.01; hyperemia: 2.1±1.3 vs 4.3±1.7%, p<0.01), whereas MBV of PL wall did not differ between groups. Coronary resistance at rest did not differ between groups, but the resistance during hyperemia was significantly greater in H than in N (IVS: 59±16 vs 31±14 mmHg·min·g·ml −1 , p<0.001; PL: 40±10 vs 30±11 mmHg·min·g·ml −1 , p<0.05). Coronary resistance at rest did not correlate with MBV, whereas that during hyperemia inversely correlated with MBV during hyperemia (r=−0.77, p<0.0001) as well as MBV at rest (r=−0.65, p<0.0001). Conclusions: Increased coronary vascular resistance during hyperemia in HCM was significantly associated with reduced MBV. MCE is useful for assessing the dynamic function of coronary circulation in the clinical setting.

Myocardial blood volume and coronary resistance during and after coronary angioplasty

2011 ◽  
Vol 300 (3) ◽  
pp. H1119-H1124 ◽  
Author(s):  
Andreas Indermühle ◽  
Rolf Vogel ◽  
Pascal Meier ◽  
Rainer Zbinden ◽  
Christian Seiler
Keyword(s):  
Blood Volume ◽  
Coronary Arteries ◽  
Coronary Angioplasty ◽  
Coronary Circulation ◽  
Perfusion Pressure ◽  
Contrast Echocardiography ◽  
Coronary Perfusion ◽  
Collateral Flow ◽  
Coronary Resistance ◽  
Myocardial Blood Volume

Animal experiments have shown that the coronary circulation is pressure distensible, i.e., myocardial blood volume (MBV) increases with perfusion pressure. In humans, however, corresponding measurements are lacking so far. We sought to quantify parameters reflecting coronary distensibility such as MBV and coronary resistance (CR) during and after coronary angioplasty. Thirty patients with stable coronary artery disease underwent simultaneous coronary perfusion pressure assessment and myocardial contrast echocardiography (MCE) of 37 coronary arteries and their territories during and after angioplasty. MCE yielded MBV and myocardial blood flow (MBF; in ml·min−1·g−1). Complete data sets were obtained in 32 coronary arteries and their territories from 26 patients. During angioplasty, perfusion pressure, i.e., coronary occlusive pressure, and MBV varied between 9 and 57 mmHg (26.9 ± 11.9 mmHg) and between 1.2 and 14.5 ml/100 g (6.7 ± 3.7 ml/100 g), respectively. After successful angioplasty, perfusion pressure and MBV increased significantly ( P < 0.001 for both) and varied between 64 and 118 mmHg (93.5 ± 12.8 mmHg) and between 3.7 and 17.3 ml/100 g (9.8 ± 3.4 ml/100 g), respectively. Mean MBF increased from 31 ± 20 ml·min−1·g−1 during coronary occlusion, reflecting collateral flow, to 121 ± 33 ml·min−1·g−1 ( P < 0.01), whereas mean CR, i.e., the ratio of perfusion pressure and MBF, decreased by 20% ( P < 0.001). In conclusion, the human coronary circulation is pressure distensible. MCE allows for the quantification of CR and MBV in humans.

Microvascular response to metabolic and pressure challenge in the human coronary circulation

2011 ◽  
Vol 301 (2) ◽  
pp. H434-H441 ◽  
Author(s):  
Stefano F. de Marchi ◽  
Steffen Gloekler ◽  
Stefano F. Rimoldi ◽  
Patrizia Rölli ◽  
Hélène Steck ◽  
...  
Keyword(s):  
Vascular Resistance ◽  
Diastolic Pressure ◽  
Contrast Echocardiography ◽  
Resistance Index ◽  
Applanation Tonometry ◽  
Myocardial Oxygen Demand ◽  
Coronary Vascular Resistance ◽  
Bicycle Exercise ◽  
Capillary Recruitment

In vivo observations of microcirculatory behavior during autoregulation and adaptation to varying myocardial oxygen demand are scarce in the human coronary system. This study assessed microvascular reactions to controlled metabolic and pressure provocation [bicycle exercise and external counterpulsation (ECP)]. In 20 healthy subjects, quantitative myocardial contrast echocardiography and arterial applanation tonometry were performed during increasing ECP levels, as well as before and during bicycle exercise. Myocardial blood flow (MBF; ml·min−1·g−1), the relative blood volume (rBV; ml/ml), the coronary vascular resistance index (CVRI; dyn·s·cm−5/g), the pressure-work index (PWI), and the pressure-rate product (mmHg/min) were assessed. MBF remained unchanged during ECP (1.08 ± 0.44 at baseline to 0.92 ± 0.38 at high-level ECP). Bicycle exercise led to an increase in MBF from 1.03 ± 0.39 to 3.42 ± 1.11 ( P < 0.001). The rBV remained unchanged during ECP, whereas it increased under exercise from 0.13 ± 0.033 to 0.22 ± 0.07 ( P < 0.001). The CVRI showed a marked increase under ECP from 7.40 ± 3.38 to 11.05 ± 5.43 and significantly dropped under exercise from 7.40 ± 2.78 to 2.21 ± 0.87 (both P < 0.001). There was a significant correlation between PWI and MBF in the pooled exercise data (slope: +0.162). During ECP, the relationship remained similar (slope: +0.153). Whereas physical exercise decreases coronary vascular resistance and induces considerable functional capillary recruitment, diastolic pressure transients up to 140 mmHg trigger arteriolar vasoconstriction, keeping MBF and functional capillary density constant. Demand-supply matching was maintained over the entire ECP pressure range.

The Effect of Ethanol and Acetaldehyde on the Metabolism and Vascular Resistance of the Perfused Heart

1971 ◽  
Vol 49 (2) ◽  
pp. 227-233 ◽  
Author(s):  
L. Gailis ◽  
M. Verdy
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Vascular Resistance ◽  
Anaerobic Glycolysis ◽  
Appreciable Effect ◽  
Coronary Vascular Resistance ◽  
Coronary Resistance ◽  
Perfused Heart ◽  
Perfused Rat Heart ◽  
Ethanol Ethanol

The effect of ethanol and acetaldehyde on the perfused nonworking rat and guinea pig hearts was studied. Ethanol (100 mM) initially increased the coronary vascular resistance, but had no appreciable effect on oxygen consumption, glucose-U-14C oxidation, or anaerobic glycolysis. Acetaldehyde (1 mM) increased the heart rate and oxygen consumption, and decreased the coronary vascular resistance. The decrease in coronary resistance was not affected by propranolol but the increase in heart rate was partially blocked. The loss of amino acids or aspartate transminase activity from the heart was not affected by the presence of ethanol. Ethanol-1-14C, either at 10 or 100 mM, was not oxidized by the perfused rat heart.

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