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Coronary microcirculation into different models of left ventricular hypertrophy-hypertensive and athlete's heart: a
V Di Bello1, D Giorgi, R Pedrinelli
1Cardiac and Thoracic Department of University of Pisa, Italy. vdibello@med.unipi.it
Insights
Hypertensive patients show impaired coronary microcirculation, unlike athletes with healthy adaptations. This study used myocardial contrast echocardiography to compare coronary flow reserve in essential hypertension and athlete's heart.
Area of Science:
- Cardiology
- Cardiovascular Physiology
- Diagnostic Imaging
Background:
- Left ventricular hypertrophy (LVH) occurs in athlete's heart and essential hypertension.
- Understanding microcirculatory differences is crucial for managing these conditions.
Purpose of the Study:
- To compare coronary microcirculatory function in patients with essential hypertension and athletes.
- To investigate adaptations in myocardial blood flow in different forms of LVH.
Main Methods:
- Quantitative myocardial contrast echocardiography with Levovist and dipyridamole stress.
- Analysis of parameters like peak intensity and microbubble wash-in/wash-out.
- Comparison between hypertensive patients (H), athletes (A), and controls (C).
Main Results:
- Hypertensive patients exhibited significantly lower microbubble appearance compared to controls and athletes.
- Coronary flow reserve (per cent increase in peak intensity post-dipyridamole) was blunted in hypertensive and athletic groups versus controls.
- Hypertensive patients showed reduced microbubble disappearance, suggesting impaired washout.
Conclusions:
- Essential hypertension is associated with impaired coronary microcirculatory function, potentially due to increased arteriolar resistance.
- Athletes demonstrate functional adaptations, including angiogenesis, for optimal substrate delivery to the hypertrophied myocardium.
- Myocardial contrast echocardiography effectively differentiates microcirculatory function in various LVH models.
Abstract:
The study was carried out in two different models of left ventricular hypertrophy: athlete's heart and essential arterial hypertension. Three groups of strictly age-matched males were studied: one group of 10 young adult untreated essential hypertensive patients (H), a second group of 10 athletes (A), and a group of 10 healthy individuals as controls (C). A Sonos 5500 echograph with S4 harmonic transducer was used with Levovist (ultrasonic tracer) before and after dipyridamole injection; digitised images of quantitative myocardial contrast echocardiography were collected with Power Harmonic Doppler. Angio images were analysed using dedicated PC software by placing a region-of-interest on the septum. Peak intensity, half-time (HT), the area under the curve of appearance and disappearance of microbubbles at 2/3 of PI, both in absolute and indexed values (/LVMi), were sampled. The per cent increase of PI after dipyridamole was significantly higher in C (+73%, P < 0.01) than in H (+31%) and in A (+33%) (P < 0.05). The area of appearance was significantly lower in H in comparison with C and A, both at rest and after vasodilatation. The disappearance area after dipyridamole was significantly higher in C and in A (+124%) than in H (+104%) (P < 0.05). Some hypothesis could be made: an impairment in the coronary microcirculatory function in hypertensive patients could be because of an in-crease in the arteriolar resistance. Angiogenesis and several different functional adaptations are the mechanisms that allow an optimal distribution of oxygen and of substrates to the hypertrophied myocardium of the athletes.
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