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Updated: Aug 7, 2026
In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography
Published on: February 16, 2016
Myocardial contrast echocardiography in assessing microcirculation in baboons with chagas disease
Miguel Zabalgoitia1, Jaime Ventura, Jose L Lozano
1The University of Texas Health Science Center at San Antonio, Division of Cardiology, San Antonio, Texas 78229-3900, USA. Zabalgoitia@uthscsa.edu
Insights
Chagasic heart disease affects 24% of infected baboons, showing impaired systolic function but preserved coronary microcirculation. Myocardial contrast echocardiography (MCE) revealed this discrepancy in a key animal model.
Area of Science:
- Cardiology
- Infectious Diseases
- Animal Models
Background:
- Chagasic cardiomyopathy is suspected to involve microvascular abnormalities.
- Understanding the interplay between microcirculation and cardiac function is crucial for Chagas disease research.
Purpose of the Study:
- To investigate the relationship between coronary microcirculation and systolic dysfunction in baboons with Chagas disease.
- To utilize myocardial contrast echocardiography (MCE) for assessing microvascular function in this model.
Main Methods:
- Seventeen *Trypanosoma cruzi*-seropositive and 13 seronegative baboons underwent MCE.
- Systolic function was assessed using left ventricular fractional shortening and ejection fractions.
- Coronary flow reserve was evaluated using dipyridamole challenge in a subset of animals.
Main Results:
- 24% of seropositive baboons exhibited impaired systolic function (reduced fractional shortening and ejection fraction).
- Myocardial contrast echocardiography (MCE) showed no significant differences in coronary microcirculation patterns between seropositive and seronegative baboons.
- Coronary flow vasoreactivity testing demonstrated a significant increase in myocardial blood flow.
Conclusions:
- Chagasic heart disease is spontaneously present in 24% of infected baboons.
- MCE indicates preserved microvascular integrity despite impaired myocardial contractility in this model.
- This baboon model offers unique insights into Chagasic cardiomyopathy pathogenesis.
Objective:
Microvascular abnormalities have been postulated in the pathogenesis of chagasic cardiomyopathy. The objective of this study was to evaluate the relationship between coronary microcirculation and systolic function impairment in baboons with Chagas disease using myocardial contrast echocardiography (MCE).
Methods:
Seventeen seropositive (5 males, 12 females; mean age 20 years) and 13 age- and gender-matched seronegative baboons underwent MCE using intravenous octafluoropropane human albumin microspheres. Color-coding was used to enhance tissue contrast in assessing regional myocardium uniformity and texture. Dipyridamole (0.54 mg/kg) was given to a subset of 4 animals to challenge coronary flow reserve. Systolic indices included left ventricular fractional shortening, velocity of circumferential fiber shortening, and left and right ventricular ejection fractions.
Results:
Four of the 17 (24%) seropositive primates had decreased fractional shortening (25 +/- 8% vs. 40 +/-5%, p <.005), velocity of circumferential fiber shortening (1.05 +/- 0.36 circ/s vs. 1.84 +/- 0.23 circ/s, p <.0001), and reduced right ventricular ejection fraction (44 +/- 9% vs. 54 +/- 4%, p <.05) compared to other seropositive animals. Seropositive and seronegative groups showed no significant differences on the coronary microcirculation pattern as evaluated by MCE, including the 4 baboons with systolic function impairment. Moreover, coronary flow vasoreactivity resulted in a significant increase in myocardial flow as detected by color-coding masking.
Conclusions:
Chagasic heart disease is present in 24% of seropositive baboons spontaneously infected with Trypanosoma cruzi. MCE reveals a discrepancy between coronary microcirculation at rest and alterations in myocardial contractility, suggesting preservation of the microvascular integrity in this unique animal model.
