Echocardiographic parameters related to right ventricular load in correlation of NT-proBNP values in acute and chronic COPD patients

Aim

The aim of the study was to assess which of the echocardiographic parameters would correlate with the degree of right ventricular function and may contribute to risk stratification in patients with severe/very severe COPD, GOLD class III/IV in correlation with Nt-proBNP in patients defined as acutely and chronically ill.

Material and methods: We have analyzed 94 patients with COPD divided in 4 groups according to GOLD classification system. Of all patients analyzed, 63 patients had an acutely worsened condition, and 31 had a stabile chronic condition. From the statistical analyses, we determined that there are no acute patients in GOLD class I, so the majority of patients are evaluated in GOLD classes III and IV. Our study analyzed 13 echo-parameters: right ventricle (mm), right atrium (mm), right atrium area, S wave from tissue Dopller of RV (m/sek), TAPSEmm, FAC%, AT of pulmonary artery(msek), SPAPmm/Hg, V max of TR (m/s), MPI of RV, GL strain of RV,PVR ,colapsibility of v.cava inf >50. All these echo-parameters were analyzed in correlation to Nt-proBNP. Correlation analysis to quantitative parameters was performed with Pearsons’s test, while in terms of qualitative parameter it was carried out with Spearmans test.

Results

From the statistical analyses, the average values of NT-proBNP in patients with an acutely worsened condition are much higher than in chronic patients within the corresponding GOLD class. The reference value for Nt-proBNP in our study was 125 pg/ml,but our results showed value of 236, 27 pg/ml with some differences between all four GOLD classes. Тhe average values in acutely worsened condition patients are far higher than in chronic patients within the respective GOLD class. The difference amounts to almost 3.5 times in GOLD class 3 and approximately 2 times in GOLD class IV. Correlations between Nt-proBNP values and echo parameters that are indicators of right heart load showed correlation to: sPAP and V-max of TR. The results of the multivariate analysis showed a significant correlation of 3 echocardiographic parameters: SPAP, MPI RV, and RV Gl. Strain in relation to the quantitative values of NT-proBNP and GOLD classes. According to the results from the Tukey post-hoc test, there was a significant difference in the distribution of NT-proBNP values between GOLD classes 2 and 3. In this regard, the average NT-proBNP value in GOLD class 2 is 238.086 pg/ml lower than that in class 3 and 4.

Conclusion

The value of NT-proBNP may be a marker for the risk of progression of COPD only from GOLD class 2 to 3, but not among the other GOLD classes. Advanced form of COPD patients (GOLD 3 nad 4 class) have more emphasized echocardiography changes of the right heart accompanied with higher values of Nt-proBNP release. SPAP, MPI RV, and RV Gl. strain in relation to the quantitative values of NT-proBNP and GOLD classes are important markers for disease progression. Key word: NT-proBNP, echocardiography, right heart failure