1000 Ventricular-vascular coupling is independently associated with exercise capacity in patients with ischemic cardiomyopathy: a cardiac multi-modality imaging study
https://doi.org/10.1186/1532-429X-10-S1-A125
© Wong et al; licensee BioMed Central Ltd. 2008
Published: 22 October 2008
Keywords
Introduction
Left ventricular (LV) systolic dysfunction due to ischemic cardiomyopathy (I-CMP) leads to reduced exercise capacity. Ventricular-vascular coupling (VVC), a ratio of effective arterial to LV elastance, represents forward flow efficiency of LV, independent of mitral regurgitation.
Purpose
In I-CMP patients, we sought to a) assess relationship between resting VVC and maximum oxygen consumption corrected for peak heart rate (MVO2/pHR), an accurate measure of exercise capacity in patients on β-blockers, and b) compare value of VVC versus other determinants of exercise capacity.
Methods
43 patients with I-CMP (age 59 ± 9 years, 88% on β-blocker) underwent cardiopulmonary exercise testing, echocardiography and cardiac magnetic resonance (CMR, 1.5 T Siemens Scanners, Erlangen Germany) for cardiac transplant evaluation. MVO2/pHR and diastolic filling variables (echocardiography) were measured in a standard fashion. CMR LV indices [end-systolic (ESV), end-diastolic (EDV), stroke volume (SV), all in ml, and LVEF] were measured using the standard contiguous short-axis slices from apex to base, using the balanced steady state free precession cine sequence (TE = 1.6 msec, TR = 3.3 msec, flip angle = 70° and slice thickness 8–10 mm, field of view varied from 228–330 in the x-direction and 260–330 in the y-direction and matrix size varied from 140–180 in the x-direction and 256 in the y-direction, giving a spatial resolution of 1.5–2.1 mm (x-direction) by 1.1–1.4 mm (y-direction). For patients able to suspend respiration, breath hold duration was 10–15 sec, depending on the heart rate; otherwise, images were acquired using 3 signal averages. Subsequently, off-line analysis was performed using Argus analytical software (Siemens Medical Solutions, Erlangen, Germany) to assess LV volumes and LVEF, in a standard fashion. VVC was calculated as: [Effective arterial elastance (end systolic pressure ÷ stroke volume index)/LV end-systolic elastance (end systolic pressure ÷ LV systolic volume index)].
Results
Univariate and multivariate predictors pf MVO2/peak HR.
MVO2/peak HR | |||
|---|---|---|---|
Correlation coefficient (rho) | P value | Multivariate analysis P value | |
Clinical characteristics | |||
Age | -0.006 | 0.9 | |
Gender | 0.1 | 0.5 | |
NYHA class | -0.14 | 0.4 | |
Baseline SBP | 0.22 | 0.16 | |
Baseline DBP | -0.02 | 0.9 | |
Echocardiographic and CMR features | |||
E max | -0.39 | 0.009 | 0.1 |
E/A ratio | -0.23 | 0.1 | |
E wave deceleration time | 0.35 | 0.02 | 0.5 |
CMR features | |||
LV end-systolic volume | -0.41 | 0.006 | 0.9 |
LV end-diastolic volume | -0.28 | 0.07 | |
Stroke volume | 0.14 | 0.3 | |
LV ejection fraction | 0.36 | 0.02 | 0.6 |
Ventricular vascular coupling | 0.45 | 0.002 | 0.001 |
Ea | -0.28 | 0.09 | |
Ees | 0.39 | 0.009 | |
Conclusion
In I-CMP patients with LV dysfunction, VVC predicts MVO2/pHR that can potentially be used as a potential therapeutic target.
Authors’ Affiliations
Copyright
This article is published under license to BioMed Central Ltd.
