Journal Article

132 Cardiac contractility index identifies systolic dysfunction in preserved ejection fraction heart failure

Straw, Sam

2023

Overview

IntroductionLeft ventricular ejection fraction (LVEF) has well-known limitations including modest reproducibility, load dependence, and representation of the percentage change in left ventricular (LV) volume rather than myocardial contractility. Although diastolic dysfunction has been proposed as a key mechanism underpinning the pathophysiology of heart failure with a preserved ejection fraction (HFpEF) the presence of subtle or concomitant systolic dysfunction has previously been suggested. We aimed to assess the prognostic value of systolic blood pressure: indexed left ventricular end-systolic volume ratio, or ‘cardiac contractility index’ (CCI).MethodsIn a prospective, observational cohort study LVEF and CCI were measured in 728 unselected individuals with newly diagnosed chronic heart failure. We divided patients into tertiles of LVEF and CCI, and also divided those with heart failure with reduced ejection fraction (HFrEF) or HFpEF by the median value of CCI (4.43mmHg/ml/m2) into four groups. Unadjusted and adjusted Poisson regression models were used to determine mortality rates for CCI and LVEF as continuous variables.ResultsThere was a modest, positive correlation between LVEF and CCI (r=0.70 [0.66-0.74], R2 0.49; p<0.0001), although the latter was distributed widely for any given value of LVEF, especially for those with HFpEF (Figure 1). We observed distinct clinical characteristics across tertiles of both LVEF and CCI, with an inverse relationship with conventional markers of risk including N-terminal B-type natriuretic peptide (p<0.001 in both comparisons) (Table 1). During 5.9 (2.9-9.0) years of follow up 491 (67.4%) patients died. There was a clear relationship between tertiles of CCI and all-cause mortality risk (p<0.001), which was less evident when patients were divided by LVEF. When modelled as continuous variables there was a curvi-linear relationship between all-cause mortality rates and CCI, but the relationship between LVEF and mortality risk was more complex, with no clear association across a wide range from 25-55%. In models including relevant covariates, the association between LVEF and mortality was no longer evident except for those with LVEF 60% (relative to 50%) but remained evident for all specified values of CCI (Table 1). Patients with HFpEF and CCI below the median value had distinct clinical characteristics (Table 2), and all-cause mortality risk ~40% higher than those with CCI above median (p<0.001), similar to those with HFrEF (Figure 2).ConclusionsCCI is a non-invasive, relatively afterload independent measure left ventricular contractility which provided additional prognostic information beyond conventional assessment by LVEF. These data could help refine the inclusion criteria of future randomised controlled trials, and its simplicity means CCI could be easily applied to existing datasets in order to identify who may have derived benefits from pharmacological therapies.Abstract 132 Table 1Unadjusted and adjusted poisson regression analyses Cardiac contractility index LVEF Unadjusted IRR (95% CI) Adjusted IRR (95% CI ) Adjusted IRR (95% CI ) Age (per year)1.06 (1.05-1.07)1.06 (1.04-1.07)1.06 (1.04-1.07)Male1.19 (0.99-1.42)1.08 (0.87-1.35)1.15 (0.93-1.43)Ischaemic heart disease1.05 (0.87-1.28)0.94 (0.76-1.17)0.96 (0.77-1.19)Diabetes mellitus1.09 (0.89-1.32)1.21 (0.98-1.50)1.22 (1.00-1.51)Hypertension1.00 (0.83-1.21)1.07 (0.87-1.32)1.05 (0.85-1.30)SBP (per mmHg)1.00 (0.99-1.00)1.00 (1.00-1.00)1.00 (0.99-1.00)HR (per beat/min)1.01 (1.00-1.01)1.01 (1.00-1.01)1.01 (1.00-1.01)log10 haemoglobin (per g/L)0.32 (0.17-0.61)0.87 (0.35-2.19)0.62 (0.25-1.51)Log10 creatinine (per μmol/L)6.61 (3.74-11.67)1.59 (0.78-3.23)1.58 (0.77-3.24)Log10 albumin0.00 (0.00-0.01)0.01 (0.00-0.16)0.01 (0.00-0.14)Log10 NTpro-BNP2.19 (1.85-2.59)1.29 (1.02-1.62)1.37 (1.09-1.72)Cardiac contractility index (mmHg/ml/m2) 21.56 (1.26-1.93)1.34 (1.03-1.75)- 41.07 (1.01-1.13)1.06 (1.00-1.13)- 4.431.001.00- 60.78 (0.67-0.92)0.78 (0.66-0.93)- 80.54 (0.39-0.74)0.61 (0.43-0.85)-LVEF (%) 201.69 (1.24-2.29)-1.27 (0.89-1.80) 301.19 (0.98-1.45)-1.01 (0.80-1.28) 400.95 (0.79-1.13)-0.89 (0.73-1.09) 501.00-1.00 600.66 (0.52-0.84)-0.69 (0.54-0.88)Abstract 132 Table 2Clinical characteristics of patients with HFrEF and HFpEF divided by median cardiac contractility index All patients (n=728) HFrEF HFpEF Low CCI (n=232) High CCI (n=61) Low CCI (n=132) High CCI (n=303) Age (years)82.6 ± 9.281.1 ± 10.3# 83.2 ± 8.583.9 ± 8.4# 83.1 ± 8.4Male sex [n(%)]330 (45.3)151 (65.1)*# 23 (37.7)*64 (48.5)*# 92 (30.4)*NYHA Class III/IV [n(%)]328 (45.1)95 (40.9)18 (29.5)55 (41.7)160 (52.8)IHD [n(%)]210 (28.8)87 (37.5)# 25 (41.0)# 33 (25.0)# 65 (21.5)# Hypertension [n(%)]490 (67.3)123 (53.0)*# 42 (68.9)*94 (71.2)# 231 (76.2)Atrial fibrillation [n(%)]263 (36.1)81 (34.9)20 (32.8)57 (43.2)105 (34.7)SBP (mmHg)140.3 ± 22.9131.6 ± 22.8*149.0 ± 20.5*133.8 ± 20.0*148.0 ± 21.4*Heart rate (beats/min)76.0 ± 16.978.7 ± 19.7# 79.5 ± 19.3# 74.4 ± 15.5# 73.8 ± 14.3# LVEF (%)48.2 ± 11.634.6 ± 9.6*# 45.0 ± 4.1*# 54.2 ± 3.5*# 56.6 ± 3.8*# CCI (mmHg/ml/m2)4.55 ± 1.922.64 ± 0.88*# 5.31 ± 0.77*# 3.69 ± 0.56*# 6.24 ± 1.37*# NT-proBNP (pg/mL)1066 (503.5-2570)2235 (788-5052)*# 813 (450-1810)*1153 (503-2353)*# 761 (401-1409)* *represents p<0.05 between cardiac contractility index categories within HFrEF and HFpEF groups. #represents p<0.05 between HFrEF and HFpEF within cardiac contractility index groups.Abstract 132 Figure 1Abstract 132 Figure 2Conflict of InterestSpeaker's fees, Honoraria and non-financial support from AstraZeneca.

• Publisher: BMJ Publishing Group Ltd and British Cardiovascular Society,BMJ Publishing Group LTD
• Subject: Contractility / Ejection fraction / Heart Failure / HFpEF / Hypertension / Mortality