Cardiopulmonary Exercise Testing Is Effective for Assessing Cardiac Amyloidosis

Cardiopulmonary exercise testing (CPET) was found to be helpful in assessing functional capacity, circulatory and chronotropic responses, and prognosis in patients with cardiac amyloidosis (CA), including those with light-chain (AL) amyloidosis.

CA is the most common type of restrictive cardiomyopathy and occurs when amyloid deposits replace normal heart muscle. Cardiac involvement dramatically worsens functional capacity and prognosis for amyloid patients. A French research team conducted a multicenter study to understand how CPET, a method to assess the heart performance at rest and during exercise, could potentially benefit functional assessment and risk stratification of patients with CA. A total of 150 patients with either AL or transthyretin CA underwent examination including CPET and follow-up over a median of 20 months. Primary endpoint was occurrence of death or heart failure hospitalization.

CPET analysis showed low levels of peak oxygen consumption (VO2) and circulatory power, at 13.0 mL/kg/min (range, 10.0-16.9 mL/kg/min) and 1,730 mmHg/mL/min (range, 1,318-2,614 mmHg/mL/min), respectively. Median N‐terminal pro B‐type natriuretic peptide (NT‐proBNP) and cardiac troponin T levels were 2,806 ng/L and 64 ng/L, respectively. At follow-up, there were 37 deaths and 44 heart failure hospitalizations.

Using multivariate Cox analysis, the investigators found that peak VO2 ≤13 mL/kg/min, circulatory power ≤1,730 mmHg/mL/min, and NT-proBNP ≥1,800 ng/L were associated with death or heart failure hospitalization. No cardiac events occurred in patients with both peak VO2 >13 mL/kg/min and NT-proBNP <1,800 ng/L, while the association of VO2 ≤13 mL/kg/min with NT-proBNP ≥1,800 ng/L was identified as a very high-risk subgroup.

“In CA, CPET is helpful in assessing functional capacity, circulatory and chronotropic responses, and the prognosis of patients along with cardiac biomarkers,” the researchers concluded.

This study was published in the European Journal of Heart Failure.