Preliminary findings of the TB-HEART Study: prevalence of cardiac pathology among newly diagnosed patients with tuberculosis with and without HIV in Zambia
Authors: Scopazzini M , Chansa P , Banda I , Ngulube J , Musukuma R , Mweemba V , Majonga E , Bual N , Schaap A , Shanaube K , Zenner D , Ayles H , Shah A S V 
Published: October 2024

Abstract

Background
Cardiovascular diseases (CVD) burden is rapidly increasing in sub-Saharan Africa (SSA) where tuberculosis and HIV prevalence remain high.(1-3) Recent data suggest pulmonary tuberculosis (PTB) is associated with increased CVD morbidity.(4) However, the mechanisms of cardiac injury remain poorly understood.

Purpose
The TB-HEART study is a cross-sectional and natural history study consecutively recruiting participants with newly-diagnosed PTB, living with and without HIV in Zambia. The primary outcome is the burden of cardiac pathology in PTB patients with and without HIV.

Methods
Participants with bacteriologically-proven PTB, consecutively recruited from an outpatient settings in Zambia, undergo detailed clinical and functional assessments including point-of-care and standard two-dimensional (2D) echocardiography. Participants are reviewed at completion of TB treatment when all assessments are repeated. The target sample size is 250 participants with PTB, with and without HIV, matched 2: 1 to participants without PTB, stratified by HIV.

Results
Since 1 November 2023, we have recruited 73 participants with a mean age of 35.3±10.9 years of whom 51/73 (69.9%) are male and 19/73 (23.5%) are living with HIV. Baseline characteristics including cardiovascular risk factors, TB symptoms, anthropometry and clinical and functional observations at presentation, stratified by HIV status, are summarised in Table 1.
We detected significant cardiac pathology (defined as left ventricular ejection fraction (LVEF) &lt;51% and/or pericardial effusion &gt;2cm in depth) in 8/65 (12.3%) participants for whom 2D-echocardiography had been completed. Median LVEF was 61.2% (IQR 57.7-67.8). LVEF was normal in 59/65 (91%); mildly abnormal in 5/65 (7.7%); and moderately abnormal in 1/65 (1.5%) participants, respectively.
Pericardial effusion &gt;0.5cm was detected in 16/65 (24.6% ) participants and maximum effusion depth was &gt;2cm in 2/16 (3.1%), 1-2cm in 12/16 (75%) and &lt;1cm in 2/16 (12.5%). 2D-echocardiography findings, stratified by HIV-status, are described in Table 2 alongside two echocardiography stills of typical pericardial effusion findings in one participant.

Conclusions
Our preliminary results demonstrate a higher than expected prevalence of cardiac pathology among participants with PTB with and without HIV, which ranges from 1-7% in autopsy studies and case series.(5-7) The most common cardiac pathology was pericardial effusion. Further analyses will include cardiac biomarkers; repeat clinical and echocardiographic assessments at TB treatment completion; and comparator data, to determine associations between prevalent cardiac pathology and PTB controlling for HIV and TB status, respectively. This may have important implications for clinical practice to prevent complications such as constrictive pericarditis; and policy design to better integrate TB and HIV patient services with preventative care to reduce future CVD risk.Table 1 - Baseline characteristicsFigure 1 and Table 2