Cardiac Biomarkers In Amyloidosis Predict Small Intestinal Bacterial Overgrowth

• Published in: Journal of cardiac failure 2024-01, Vol.30 (1), p.277-278
• Main Authors: Chua, Frederick, Banerjee, Shoujit, Kunkel, David C., Lombardo, Dawn, Ghashghaei, Roxana
• Format: Article
• Language: English
• ISSN: 1071-9164; 1532-8414
• DOI: 10.1016/j.cardfail.2023.10.380

Cardiac amyloidosis is an underrecognized cause of heart failure, and gastrointestinal (GI) amyloidosis can result in gut dysmotility and small intestinal bacterial overgrowth (SIBO). SIBO has various consequences, such as mucosal injury and nutrient malabsorption, impacting overall patient health. The interplay between cardiac and GI amyloidosis, especially in the context of SIBO, is largely undefined. This study evaluates associations between cardiac biomarkers (NT-proBNP level, echocardiographic indices) and extracardiac biomarkers in the gut, specifically non-invasive GI breath testing for SIBO. We hypothesize that patients with more severe cardiac amyloidosis may have a higher prevalence of SIBO and altered gut motility patterns, as detected via non-invasive GI breath testing. Nine patients presenting to tertiary referral cardiology and gastroenterology clinics for evaluation of AL or ATTR amyloidosis were analyzed. Demographic data, baseline echocardiogram, and NT-proBNP levels were collected. Patients underwent 3-hour lactulose breath testing with hydrogen and methane gas levels measured at 15-min intervals. Pearson correlation coefficients were calculated between cardiac indices, peak methane gas production (marker of delayed motility), and rise in hydrogen gas from baseline to 90 minutes (small intestinal phase, diagnostic of SIBO when >20 ppm) on breath testing. Nine patients (mean age 60 [48-77], 44% F) were assessed; five with AL amyloidosis and four with ATTR amyloidosis. Eight patients had preserved ejection fraction (EF>55%). NT-proBNP levels correlated significantly with the rise in hydrogen gas at 90 min (r=.80, p=.009) [Figure 1a]. A negative correlation was observed between overall methane gas peak and NT-proBNP levels (r=-0.48, p=.009) [Figure 1b]. The correlation between the rise in hydrogen gas and grade of diastolic dysfunction was significant (r=.83, p=.04) [Figure 1c]. A positive association was identified between NT-proBNP levels and early, excessive rise in hydrogen gas on GI breath testing, suggesting cardiac biomarkers may predict extracardiac manifestations of amyloidosis in the gut, particularly SIBO. This association enables earlier screening and treatment of SIBO in patients with advanced cardiac amyloidosis, addressing symptoms like bloating, malabsorption, and interference with anticoagulant dosing. The positive association between diastolic dysfunction grade and hydrogen gas rise [Figure 1c] and the negative association