Intestinal blood flow reduced in patients with chronic HF

Patients with chronic HF have reduced intestinal blood flow compared with patients without chronic HF, which potentially contributes to increased bacterial growth and gastrointestinal symptoms, according to results of a recent prospective study.

Researchers measured the arterial intestinal blood flow in 65 patients with chronic HF and 25 control participants. Among patients with HF, 12 had cachexia. All participants underwent echocardiography and left ventricular ejection fraction measurement, as well as symptom-limited treadmill exercise testing. Intestinal blood flow and bowel wall thickness were measured via ultrasound, and the presence of gastrointestinal symptoms was determined according to responses to the Gastrointestinal Symptom Rating Scale.

“Intestinal arterial blood flow is reduced in patients with chronic HF, which may contribute to increased growth of juxtamucosal bacteria, inflammation, [gastrointestinal] symptoms and cardiac cachexia complicating advanced stages of HF,” the researchers wrote.

Patients with chronic HF had a 30% to 43% reduction in mean systolic blood flow vs. controls in the superior and inferior mesenteric arteries, as well as the celiac trunk (P<.007 for all comparisons). Blood flow was most reduced among patients with cachexia (P<.002). Researchers noted a significant correlation between the severity of HF and reduced blood flow in the celiac trunk and the superior mesenteric artery (P<.04 for both).

Bowel wall thickness was increased among patients in the small bowel and ascending, descending, sigmoid and transverse colon compared with controls (P<.01 for all comparisons). Patients with HF also reported gastrointestinal symptoms more frequently, including feelings of repletion (P=.014), burping (P=.016) and intestinal murmurs (P=.027). Symptoms of burping and intestinal murmurs were more severe among patients with cachexia compared with nonchacectic patients.

Lower blood flow was significantly associated with increased symptoms of abdominal discomfort, as well as higher serum levels of immunoglobulin A-antilipopolysaccharide (r=0.76; P<.02) and C-reactive protein (r=0.43; P=.02). The researchers also noted an increase in juxtamucosal bacteria among patients with HF, and correlations between higher juxtamucosal bacteria concentrations and lower systolic blood flow (r=0.64; P=.047) and serum immunoglobulin A-antilipopolysaccharide (r=0.55; P=.05).

Multivariate analysis indicated a significant correlation between cardiac cachexia and reduced blood flow in the superior mesenteric artery (P<.04), as well as a borderline significant link between cachexia and lower blood flow in the inferior mesenteric artery (P=.056).

In a related editorial, Benjamin Dicken, MBBS, of the cardiology department at Castle Hill Hospital in Hull York Medical School in Kingston upon Hull, United Kingdom, and John G.F. Cleland, MD, of the National Heart and Lung Institute, Imperial College, London, suggested that these findings be interpreted with caution.

“Many [CV] drugs, including diuretic agents and mineralocorticoid antagonists, have effects on gut function, and the control group biopsied are unlikely to reflect a truly normal healthy population,” they wrote.

Dicken and Cleland also acknowledged studies assessing the link between gut bacteria and HF progression by modifying the amount or type of bacteria present via antibiotics or changes to the bowel environment. “Should either approach prove effective, large-scale studies should evaluate ‘if the way to a man’s heart is truly through his stomach,’” they concluded.

For more information:

Dicken B. J Am Coll Cardiol. 2014;doi:10.1016/j.jacc.2014.06.1180.

Sandek A. J Am Coll Cardiol. 2014;doi:10.1016/j.jacc.2014.06.1179.

Disclosure: See the full study for a list of relevant financial disclosures.