CARDIOVASCULAR JOURNAL OF AFRICA • Volume 34, No 4, September/October 2023 AFRICA 221 The Pearson’s correlation coefficients between various echocardiographic measures of LV systolic and diastolic function and the RV FAC, TAPSE, RV S′ and RV MPI are shown in Table 4. The indices of LV systolic function [LVEF and left ventricular outflow tract velocity–time integral (LVOT VTI)] were the strongest correlates of the various measures of RVSD. The LVEF and LVOT VTI showed significant positive correlations with RV FAC, TAPSE and RV S′ and negative correlations with RV MPI. Multivariate linear regression analyses were performed using variables that showed a significant correlation with RV FAC in the univariate analysis. The final linear regression prediction model for RV FAC contained the LVOT VTI (with log10 transformation), RV size as measured at the proximal right ventricular outflow tract (RVOT), the left atrial volume index (LAVI) and the LVEF. The model was statistically significant [F (4, 206) = 79.315, p < 0 .001] and accounted for approximately 59.9% of the variance of RV FAC (R2 = 0.606, adjusted R2 = 0.599). RV FAC was primarily predicted by log10 LVOT VTI (β = 40.295, p < 0.001) and to a lesser extent by proximal RVOT diameter (β = –2.858, p = 0.009) and LAVI (β = –0.099, p < 0.001). ROC curve analysis was used to determine the threshold value of LVOT VTI that was associated with RVSD. The ROC analysis defined an LVOT VTI value of < 9.8 cm as the cut-off value for an RV FAC < 35% [area under the curve (AUC) = 0.882; 95% confidence interval (CI): 0.838–0.926, p < 0.001) with a sensitivity of 81.5% and specificity of 81.9% (Fig. 2). Table 5 shows the LVOT VTI cut-off values for the various measures of RVSD. Binary logistic regression analysis was performed to ascertain the effects of various clinical and echocardiographic characteristics on the likelihood that the participants would have RVSD, defined as RV FAC < 35%, TAPSE < 1.6 cm, RV S′ < 10 cm/s or RV MPI > 0.55. Only variables that were significant at an alpha level of 0.05 in the univariate analyses were included in the multivariable analysis. The variables tested included age, gender, systolic blood pressure (SBP), New York Heart Association (NYHA) class, body mass index, heart rhythm, aetiology of HF, diastolic parameters (including the transmitral E/A ratio), PASP, LVEF, LAVI and RV size. The final multivariate logistic regression model included LVEF < 40%, mitral valve E/A ratio > 2, PASP ≥ 35 mmHg and SBP < 140 mmHg and was statistically significant [χ2 (4) = 62.921, p < 0.001] (Table 6). The model explained 42.4% of the variance in RVSD and correctly classified 84.5% of cases. Table 3. Aetiology of heart failure among the study participants Characteristics Count Percentage Aetiology of heart failure Hypertensive heart disease 141 52.2 Dilated cardiomyopahy 53 19.6 Ischaemic heart disease 26 9.6 Peripartum cardiomyopathy 16 5.9 Valvular heart disease 16 5.9 Infiltrative and other restrictive cardiomyopathies 8 3.0 Othersa 10 3.7 Total 270 100.0 Type of dilated cardiomyopathy Idiopathic 44 83.0 Alcohol-related 4 7.5 Chemotherapy-associated 2 3.8 Suspected myocarditis 2 3.8 Thyroid disease-associated 1 1.9 Total 53 100.0 Type of valvular heart disease Rheumatic 10 62.5 Endocarditis 3 18.8 Calcific/degenerative 2 12.5 Mitral valve prolapse 1 6.3 Total 16 100.0 aIncluded three cases of cancer therapeutics-related cardiac dysfunction in breast cancer patients taking anthracyclines, three cases of suspected myocarditis, one case of hypertrophic cardiomyopathy and three cases of left ventricular systolic/ diastolic dysfunction of uncertain aetiology. Table 4. Correlations between the indices of RVSD and those of LV systolic and diastolic dysfunction RV FAC TAPSE RV S’ RV MPI Variable r p-value r p-value r p-value r p-value LVEDV –0.299 < 0.001* –0.123 0.044* –0.195 0.002* 0.157 0.022* LVESV –0.392 < 0.001* –0.267 < 0.001* –0.330 < 0.001* 0.190 0.006* LVEF 0.540 < 0.001* 0.446 < 0.001* 0.561 < 0.001* –0.245 < 0.001* LVOT VTI 0.657 < 0.001* 0.573 < 0.001* 0.542 < 0.001* –0.250 < 0.001* MV E/A –0.437 < 0.001* –0.515 < 0.001* –0.456 < 0.001* 0.272 < 0.001* MV E/e′ –0.314 < 0.001* –0.391 < 0.001* –0.348 < 0.001* 0.127 0.093 MV DT 0.413 < 0.001* 0.438 < 0.001* 0.307 < 0.001* –0.217 0.005* DT, deceleration time; E/e′, early filling velocity to early diastolic annular velocity ratio; LVEDV, left ventricular end-diastolic volume; LVEF, left ventricular ejection fraction; LVESV, left ventricular end-systolic volume; LVOT VTI, left ventricular outflow tract velocity–time integral; MV, mitral valve; TV, tricuspid valve. r = Parson’s correlation coefficient, *p-value is statistically significant. Sensitivity 1 – Specificity 0.0 0.2 0.4 0.6 0.8 1.0 1.0 0.8 0.6 0.4 0.2 0.0 Fig. 2. ROC curve of LVOT VTI and RV FAC < 35%.
RkJQdWJsaXNoZXIy NDIzNzc=