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Right ventricular to pulmonary artery coupling and outcome in patients with cardiac amyloidosis
Right ventricular to pulmonary artery coupling and outcome in patients with cardiac amyloidosis
REVIEWED BY Chrissy Thomson, AFASA | ASA SIG: Cardiac
REFERENCE | Authors: Tomasoni D, Adamo M, Porcari A, Aimo A, Bonfioli G, Castiglione V, et al.
WHY THE STUDY WAS PERFORMED
Right ventricular to pulmonary artery (RV-PA) coupling relates to the ability of the RV to increase contractility to match RV afterload (pulmonary arterial pressures). When RV contractility cannot rise to match RV afterload, RV-PA uncoupling occurs, resulting in RV dysfunction and RV failure. This study aimed to (1) investigate the prognostic value of the echocardiographic assessment of RV-PA coupling in patients with cardiac amyloidosis (CA), and (2) whether this measurement could provide superior prognostic information compared to the stand-alone measurements of tricuspid annular plane systolic excursion (TAPSE) and pulmonary artery systolic pressure (PASP).
HOW THE STUDY WAS PERFORMED
A retrospective evaluation of echocardiographic studies was performed on consecutive patients diagnosed with immunoglobulin light chain (AL) or transthyretin (ATTR) CA from 2011 to 2021. A total of 283 patients were included in the analysis, with 63% of the study population being male, and a median age of 76 years. RV-PA coupling was measured using the TAPSE/PASP ratio. TAPSE was measured from an RV-focused apical four-chamber view. The PASP was measured using the equation:
4 x [TR peak velocity]2 + [estimated right atrial pressure*]
*Based on inferior vena cava collapsibility and size.
Other standard measurements were included for analysis and were stratified by the TAPSE/ PASP ratio. These included left and right ventricular size, wall thickness and function, and atrial size. Measurements were performed according to recommendations by the American Society of Echocardiography and the European Association of Cardiovascular Imaging. The primary endpoint for the study was the composite of all-cause death or heart failure (HF) hospitalisation, with a secondary endpoint being all-cause death. Data was collected using electronic health records, chart review and patient reporting.
WHAT THE STUDY FOUND
The median value of the TAPSE/PASP ratio across the 283 patients was 0.45 mm/mmHg. Patients with TAPSE/ PASP < 0.45 mm/mmHg were older, had a higher prevalence of ATTR-CA, presented with lower systolic blood pressure, had more severe symptoms and had higher rates of atrial fibrillation. In addition, these patients had greater ventricular wall thickness, poorer LV systolic and diastolic function, greater RV dilatation, poorer RV function, and more dilated atria.
The optimal cut-off for predicting the prognosis of the primary endpoint was found to be 0.47 mm/mmHg, according to receiver operator curve (ROC) analysis. It was also found that while the stand-alone TAPSE and PASP measurements were significantly related to the study endpoints, the TAPSE/PASP ratio < 0.45 mm/mmHg provided a more comprehensive assessment of right heart performance and prognostic information than either TAPSE or PASP alone (see Table 4 in original article).
The TAPSE/PASP ratio was more effective than TAPSE or PASP in predicting prognosis.
RELEVANCE TO CLINICAL PRACTICE
Stand-alone measurements of TAPSE and PASP are currently routine inclusions in an echocardiographic study. An additional, simple calculation of the TAPSE/PASP ratio will provide clinicians with additional prognostic information in patients with cardiac amyloidosis, enabling closer monitoring of those patients found to be at higher risk of death and hospitalisation.
