Physical properties of the mitral valve tissue assessed by tissue sound speed in cardiac amyloidosis: relationship to the severity of mitral regurgitation

Cardiac Amyloidosis and Valvular Heart Disease

Growing interest has accrued in the co-existence of cardiac amyloidosis and valvular heart disease. Amyloid infiltration from either transthyretin (ATTR) or of light chain (AL) origin may affect any structure of the heart, including the valves. The recent literature has mainly focused on aortic stenosis and cardiac amyloidosis, improving our understanding of the epidemiology, diagnosis, treatment and prognosis of this dual pathology. Despite being of high clinical relevance, data on mitral/tricuspid regurgitation and cardiac amyloidosis are rather scarce and mostly limited to case reports and small cases series. It is the aim of this review article to summarize the current evidence of concomitant valvular heart disease and cardiac amyloidosis by including studies on epidemiology, diagnostic approaches, screening possibilities, therapeutic management, and prognostic implications.

Initial experience with percutaneous mitral valve repair in patients with cardiac amyloidosis

BACKGROUND

Percutaneous mitral valve repair (PMVR) is a therapeutic option for severe mitral regurgitation (MR) in patients with heart failure due to differential aetiologies. However, only little is known about the safety and efficacy of this procedure in patients with amyloid cardiomyopathy.

METHODS

Five patients with cardiac amyloidosis and moderate to severe or severe MR undergoing PMVR were analysed retrospectively and compared to seven patients with cardiac amyloidosis and severe MR without intervention. Clinical and functional data, renal function and cardiac biomarkers as well as established risk scores for cardiac amyloidosis were assessed. Primary endpoint was the reduction in MR one year after PMVR. Secondary endpoints were safety, overall mortality after 12 months compared with the control group, as well as changes in clinical and functional parameters.

RESULTS

Amyloidosis risk assessment documented amyloid cardiomyopathy at an advanced stage in all patients. Procedural, technical and device success of PMVR were all 100% and residual MR remained mild to moderate at 12 months follow-up (P = .038 vs before PMVR). Differences in survival compared with the control (no PMVR) group pointed to a possible survival benefit in the PMVR group (P = .02).

CONCLUSION

PMVR is a feasible and safe procedure in patients with cardiac amyloidosis and might carry a possible survival benefit in this patient group.

Impact of tricuspid regurgitation on survival in patients with cardiac amyloidosis

AIMS

Tricuspid regurgitation (TR) is a common finding and has been associated with poorer outcome in patients with heart failure. This study sought to investigate the prognostic value of TR in patients with cardiac amyloidosis (CA).

METHODS AND RESULTS

Two-hundred and eighty-three patients with CA-172 (61%) wild-type transthyretin amyloidosis (ATTRwt) and 111 (39%) light-chain amyloidosis (AL)-were consecutively enrolled between December 2010 and September 2019. Transthoracic echocardiographies at time of diagnosis were reviewed to establish the presence and severity of TR and its relationship with all-cause mortality during patients' follow-up. Seventy-four (26%) patients had a moderate-to-severe TR. Moderate-to-severe TR was associated with New York Heart Association status (P < 0.001), atrial fibrillation (P = 0.003), greater levels of natriuretic peptides (P = 0.002), worst renal function (P = 0.03), lower left ventricular ejection fraction (P = 0.02), reduced right ventricular systolic function (P = 0.001), thicker tricuspid leaflets (P = 0.019), greater tricuspid annulus diameter (P = 0.001), greater pulmonary artery pressure (P = 0.001), greater doses of furosemide (P = 0.001), and anti-aldosterone (P = 0.01) and more anticoagulant treatment (P = 0.001). One hundred and thirty-four (47%) patients met the primary endpoint of all-cause mortality. After multivariate Cox analysis, moderate-to-severe TR was significantly associated with mortality [hazard ratio 1.89, 95% confidence interval (1.01-3.51), P = 0.044] in patients with ATTRwt. There was no correlation between TR and death [hazard ratio 0.84, 95% confidence interval (0.46-1.51), P = 0.562] in patients with AL.

CONCLUSIONS

Moderate-to-severe TR is frequent in CA, and it is an independent prognosis factor in patients with ATTRwt but not in patients with AL.

Quantitative Differentiation of Pneumonia from Normal Lungs: Diagnostic Assessment Using Photoacoustic Spectral Response

Pneumonia is an acute lung infection that takes life of many young children in developing countries. Early stage (red hepatization) detection of pneumonia would be pragmatic to control mortality rate. Detection of this disease at early stages demands the knowledge of pathology, making it difficult to screen noninvasively. We propose photoacoustic spectral response (PASR), a noninvasive elasticity-dependent technique for early stage pneumonia detection. We report the quantitative red hepatization detection of pneumonia through median frequency, spectral energy, and variance. Significant contrast in spectral parameters due to change in sample elasticity is found. The tissue-mimicking phantom study illustrates a 39% increase in median frequency for 1.5 times the change in density. On applying to formalin-fixed pneumonia-affected goat lungs, it provides a distinct change in spectral parameters between pneumonia affected areas and normal lungs. The obtained PASR results were found to be highly correlating to standard histopathology. The proposed technique therefore has potential to be a regular diagnostic tool for early pneumonia detection.

Distribution of the microelastic properties within the human anterior mitral leaflet

Knowledge of the biomechanical properties of the mitral valve leaflets and their relation to histologic structure is of importance for understanding the leaflet movement characteristics under normal and pathologic conditions, but such knowledge is not yet available. The aim of this study was to determine biomechanical properties of the human anterior mitral leaflet on a microscopic scale. We used scanning acoustic microscopy (SAM) to examine the human anterior mitral leaflet. Sections of fixed human anterior mitral leaflet tissue were obtained from postmortem human anterior mitral leaflets (n = 5). We measured the speed of sound (nu(L)) in each histologic layer in three regions-of-interest (ROIs): these were at the annular edge, at the valve midpoint and close to the free edge. nu(L) varied in the three histologic layers (p < 0.01). It was higher in the fibrous layer (1.76 km/s) compared with the atrial layer (1.75 km/s) and ventricular layer (1.73 km/s). Also, nu(L) differed between positions along the length of the annulus-free edge line (p < 0.01), showing a decline from the annular edge (1.76 km/s) to the free edge (1.73 km/s), both as a whole and also within the atrial and the fibrous layer. These results demonstrate that the fibrous layer is stiffer than the atrial and ventricular layer and that the leaflet as a whole and within the atrial and the fibrous layer is stiffer at the annulus part in comparison with those near the free edge. (E-mail: ).