Abstract
BackgroundIn patients with advanced non-ischemic cardiomyopathy (NIC), right-sided cardiac disturbances has prognostic implications. Right coronary artery (RCA) flow pattern and flow reserve (CFR) are not well known in this setting. The purpose of this study was to assess, in human advanced NIC, the RCA phasic flow pattern and CFR, also under right-sided cardiac disturbances, and compare with left coronary circulation. As well as to investigate any correlation between the cardiac structural, mechanical and hemodynamic parameters with RCA phasic flow pattern or CFR.MethodsTwenty four patients with dilated severe NIC were evaluated non-invasively, even by echocardiography, and also by cardiac catheterization, inclusive with Swan-Ganz catheter. Intracoronary Doppler (Flowire) data was obtained in RCA and left anterior descendent coronary artery (LAD) before and after adenosine. Resting RCA phasic pattern (diastolic/systolic) was compared between subgroups with and without pulmonary hypertension, and with and without right ventricular (RV) dysfunction; and also with LAD. RCA-CFR was compared with LAD, as well as in those subgroups. Pearson's correlation analysis was accomplished among echocardiographic (including LV fractional shortening, mass index, end systolic wall stress) more hemodynamic parameters with RCA phasic flow pattern or RCA-CFR.ResultsLV fractional shortening and end diastolic diameter were 15.3 ± 3.5 % and 69.4 ± 12.2 mm. Resting RCA phasic pattern had no difference comparing subgroups with vs. without pulmonary hypertension (1.45 vs. 1.29, p = NS) either with vs. without RV dysfunction (1.47 vs. 1.23, p = NS); RCA vs. LAD was 1.35 vs. 2.85 (p < 0.001). It had no significant correlation among any cardiac mechanical or hemodynamic parameter with RCA-CFR or RCA flow pattern. RCA-CFR had no difference compared with LAD (3.38 vs. 3.34, p = NS), as well as in pulmonary hypertension (3.09 vs. 3.10, p = NS) either in RV dysfunction (3.06 vs. 3.22, p = NS) subgroups. ConclusionIn patients with chronic advanced NIC, RCA phasic flow pattern has a mild diastolic predominance, less marked than in LAD, with no effects from pulmonary artery hypertension or RV dysfunction. There is no significant correlation between any cardiac mechanical-structural or hemodynamic parameter with RCA-CFR or RCA phasic flow pattern. RCA flow reserve is still similar to LAD, independently of those right-sided cardiac disturbances.
Highlights
In patients with advanced non-ischemic cardiomyopathy (NIC), right-sided cardiac disturbances has prognostic implications
Under acute and marked increasing of right ventricle (RV) systolic pressure, it was observed a decreasing in Right coronary artery (RCA) flow followed by a subsequent RV failure [10]
The RV function, analyzed by radionuclide ventriculography, have presented a RV EF mean value of 0.35 ± 0.11 for the entire group of patients, and it was possible to divide two subgroups to comparison according to ejection fraction
Summary
In patients with advanced non-ischemic cardiomyopathy (NIC), right-sided cardiac disturbances has prognostic implications. The purpose of this study was to assess, in human advanced NIC, the RCA phasic flow pattern and CFR, under right-sided cardiac disturbances, and compare with left coronary circulation. When RV systolic hypertension occurs, the RCA systolic flow is attenuated because of reduction in systolic coronary driving pressure to RV [7,9] These findings could not be extrapolated to humans, mainly due to differences with animal anatomy and physiologic conditions [13]. In presence of dilated non-ischemic cardiomyopathy (NIC), most studies refers only to LAD [16,17,18,19], and, in someway, extrapolates to global coronary circulation, not considering the possible influences from right sided disturbances. Under acute and marked increasing of RV systolic pressure, it was observed a decreasing in RCA flow followed by a subsequent RV failure [10]
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