An analysis of imaging modalities to assess the right and left heart in pulmonary hypertension with left-to-right shunts.

Background

Pulmonary hypertension (PH) secondary to congenital left-to-right shunts leads to serious consequences in sub-Saharan Africa. This study used various imaging modalities to assess right and left heart dimensions and functions in patients with secondary PH.

Methods

Patients with a mean pulmonary artery pressure ≥ 25 mmHg during right heart catheterisation underwent transthoracic echocardiography, cardiac magnetic resonance imaging (CMRI), and nuclear ventriculography.

Results

Seventy-five patients (median age 9.98: 6.01-40.9 years) were included. Right-heart dilation was observed in all, with increased tricuspid valve annular diameter (median z-score 2.44) on echocardiography. Similarly, right ventricular (RV) end-diastolic indexed volumes were at least double the normal reference ranges in most patients (median 240: 165-268 mL/m2) on CMRI. The median normal RV systolic function was 49% for males (IQ1-IQ3, 48.0-50.0%) and 49% for females (IQ1-IQ3, 47.3-49.8%). CMRI showed that 70% of males had a normal RV systolic function compared to only 45% of females (p < 0.05). Echocardiographic markers of RV function correlated poorly with CMRI RV ejection fraction, with correlation coefficients of r = -0.28, r = -0.10, and r = -0.04. Notably, 80% of our patients demonstrated left heart dilation, and 35% had impaired left ventricular (LV) ejection fraction on echocardiography, radionuclide ventriculography, and CMRI.

Conclusion

Echocardiography and CMRI consistently revealed right heart dilation but correlated poorly for right heart function. The evaluation of LV function should not be neglected, as some patients exhibited decreased LV ejection fraction. A holistic approach incorporating multiple modalities and clinical assessment is recommended, as the pathophysiology of PH may differ in patients with left-to-right shunts.