Volume 10 Supplement 1

Abstracts of the 11th Annual SCMR Scientific Sessions - 2008

Open Access

1000 Ventricular-vascular coupling is independently associated with exercise capacity in patients with ischemic cardiomyopathy: a cardiac multi-modality imaging study

  • Raymond C Wong1,
  • Carlos Dumont1,
  • Bethany A Austin1,
  • Deborah H Kwon1,
  • Scott D Flamm1,
  • James D Thomas1,
  • Randall C Starling1 and
  • Milind Y Desai1
Journal of Cardiovascular Magnetic Resonance200810(Suppl 1):A125

https://doi.org/10.1186/1532-429X-10-S1-A125

Published: 22 October 2008

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

Mean LVEF, ESV, EDV, and SV were 24 ± 8%, 228 ± 107 ml, 297 ± 111 ml, and 66 ± 20 ml respectively. Mean MVO2/pHR was 13 ± 3 ml/beat. Predictors of MVO2 are shown in Table 1. On stepwise regression, only VVC significantly predicted MVO2/pHR.
Table 1

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

 

NYHA indicates New York Heart Association; SBP, systolic blood pressure; DBP, diastolic blood pressure; E max, mitral E wave velocity; LV, left ventricle; Ea, Arterial elastance; Ees, left ventricular systolic elastance.

Conclusion

In I-CMP patients with LV dysfunction, VVC predicts MVO2/pHR that can potentially be used as a potential therapeutic target.

Authors’ Affiliations

(1)
Cleveland Clinic

Copyright

© Wong et al; licensee BioMed Central Ltd. 2008

This article is published under license to BioMed Central Ltd.

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