Anatomic fitting studies of a total artificial heart in heart transplant recipients: Critical dimensions and prediction of fit

Anatomic fitting studies of the Cleveland Clinic-Nimbus total artificial heart were performed in 33 patients undergoing heart transplantation. The pump fit in the pericardial space in 20 men (80%) and 4 women (50%). There was no significant difference between the Fit and Non-Fit groups in external chest dimensions. Among 42 intrathoracic dimensions, the distance from the center of the mitral valve to the diaphragm (Fit: 5.6 ± 2.2 cm, Non-Fit: 3.6 ± 0.4 cm, p < 0.00001) and the distance from the caudal end of the pulmonary valve to the diaphragm (Fit: 9.4 ± 1.6 cm, Non-Fit: 6.3 ± 0.8 cm, p < 0.0001) were the most critical. To predict anatomic fit, an index (A × B × C) was obtained from chest X-ray measurements (A, the craniocaudal distance from the dorsal region of the 8th left rib to the left diaphragm; B, the maximum left chest width; and C, the maximum anteroposterior sternum-vertebrae dimension). The pump fit in 88.5% of the patients with an index above 1200 cm³, whereas it fit in only 14.3% of the patients with an index below 1200 cm³ (p < 0.001). This index was an easily obtainable, good predictor of anatomic fit.