Regional left ventricular function does not predict survival in ischaemic cardiomyopathy after cardiac surgery

Abstract

Objectives: To define the prognostic contribution of global and regional left ventricular (LV) function measurements in patients with ischaemic cardiomyopathy randomised to coronary artery bypass graft surgery (CABG) with (n=501) or without (n=499) surgical ventricular reconstruction (SVR).

Methods: Novel multivariable methods to analyse global and regional LV systolic function were used to better formulate prediction models for long-term mortality following CABG with or without SVR in the entire cohort of 1000 randomised SVR hypothesis patients. Key clinical variables were included in the analysis. Regional function was classified according to the discreteness of anteroapical hypokinesia and akinesia into those most likely to benefit from SVR, those least likely and those felt to have intermediate likelihood of benefit from SVR.

Results: The most prognostic clinical variables identified in multivariable models include creatinine, LV end-systolic volume index (ESVI), age and NYHA (New York Heart Association) class. Addition of LV ejection fraction, LV end-diastolic volume index and regional function assessment did not contribute additional power to the model. Subgroup analysis based on regional function did not identify a cohort in which SVR improved mortality.

Conclusions: ESVI is the single parameter of LV function most predictive of mortality in patients with LV systolic dysfunction following CABG with or without SVR in multivariable models that include all key clinical and LV systolic function parameters. Assessment of regional cardiac function does not enhance prediction of mortality nor identify a subgroup for which SVR improves mortality. These results do not support elective addition of LV reconstruction surgery in patients undergoing CABG.

Trial registration number: NCT00023595.

Keywords: coronary artery bypass grafting; end-systolic volume index; ischaemic cardiomyopathy; randomised clinical trial; surgical ventricular reconstruction.

Conflict of interest statement

Competing interests: DSB participates in royalties to Cedars-Sinai for the software used for some of the SPECT analysis.

© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Figures

Figure 1

Availability of Baseline Cardiac Imaging Studies for Core Laboratory Assessment

Figure 2

Scatterplot of LVEF by ESVI values. Patients with a reported ESVI are plotted in blue and imputed ESVI values are plotted in orange.

Figure 3

Regional LV Dysfunction Pattern in Three Patient Groups Based on SVR Eligibility – Segment 1 is the basal anterior segment. The distribution of dyskinesia as percentage of the 812 patients separated by SVR eligibility (top) and distribution of patients with akinesia with or without dyskinesia (bottom).

Figure 4

Relationship of ESVI to Survival by Operation Received at 1, 3, and 5 Years in 979 SVR Hypothesis Patients (21 patients received no operation) - Reference lines denote tertiles of ESVI.

Figure 5

Survival by Treatment Received in SVR Eligibility Groups Based on Regional Function (5A= most eligible, 5B= intermediate eligibility, 5C= least eligible) - Hazard ratios (95% CI) on each plot are for CABG+SVR versus CABG only. Treatment received-by-SVR eligibility group interaction p-value=0.45