Pulmonary 99mTc-HMDP uptake correlates with restrictive ventilatory defects and abnormal lung reactance in transthyretin cardiac amyloidosis patients

Abstract

Background Pulmonary involvement in individuals with transthyretin cardiac amyloidosis is unclear. The aim of this study was to quantify 99mTc-hydroxy methylene diphosphonate (HMDP) lung retention in hereditary transthyretin (ATTRv) cardiac amyloidosis patients and to relate tracer uptake intensity to pulmonary function and aerobic capacity. Methods We prospectively enrolled 20 patients with biopsy-proven ATTRv cardiac amyloidosis and 20 control subjects. Cardiac involvement was confirmed by echocardiography and nuclear imaging using 99mTc-HMDP. Semi-quantitative analysis of the heart, rib and lung retention was assessed using a simple region of interest technique. Pulmonary function was evaluation by the means of whole-body plethysmography, diffusing capacity of the lung for carbon monoxide, forced oscillation technique and cardiopulmonary exercise testing. Results Pulmonary tracer uptake estimated by lung to rib retention ratio was higher in ATTRv amyloidosis patients compared with control subjects: median 0.62 (0.55–0.69) vs 0.51 (0.46–0.60); p = 0.014. Analysis of relation between lung 99mTc-HMDP retention and pulmonary function parameters shown statistically significant correlations with total lung volume (% predicted), lung reactance (Xrs 5 Hz) and peak VO2, suggesting total lung capacity restriction impaired elastic properties of the lung and poor aerobic capacity. Conclusion Our study suggests that some grade of pulmonary retention of 99mTc-HMDP may occur in patients with cardiac ATTRv amyloidosis, which can elicit deleterious effects on patient’s lung function and aerobic capacity.

Radiopharmaceutical supply disruptions and the use of 99mTc-hydroxymethylene diphosphonate as an alternative to 99mTc-pyrophosphate for the diagnosis of transthyretin cardiac amyloidosis: An ASNC Information Statement

“…Extra-cardiac uptake was found predominantly in the lungs and pleura in ATTR and in AL, followed by the digestive track and subcutaneous tissues in hereditary ATTR and AL cardiac amyloidosis. Another study by Monfort et al, 18 specifically looked at lung retention in hereditary ATTR, showing that pulmonary retention of HMDP was higher in hereditary ATTR amyloidosis patients compared with age and sex matched control subjects. Another study from Cappelli et al 19 found 99m Tc-HMDP scintigraphy showed lung uptake in almost 60% of subjects with ATTR amyloidosis, and that the incidence of lung uptake was significantly correlated to the grade of heart retention according to Perugini visual score.…”