Radiologic assessment of HeartMate II position: Minimal pump migration after long-term support

Surgical positioning of the HeartMate II (HMII) left ventricular assist device assuring an unobstructed blood flow path is essential for optimal device function and hemodynamic support. We report a non-invasive radiologic assessment of HMII position after implant and long-term follow-up.

We reviewed 132 consecutive patients (age 64 ± 14 years; 86% male; 60% destination therapy) implanted with an HMII from January 2009 to December 2012 and followed for them for up to 4 years. A radiologist measured pump position, pocket depth and cannula angles using chest radiography. Changes over time were determined in 64 of these patients with pairs of radiographs immediately after implant and at an average of 2.0 ± 0.7 years of follow-up.

The axis of the pump relative to the spine was 92 ± 10° at baseline and 94 ± 9° at 2 years (n = 64, p = 0.02), and inflow cannula angles averaged 21 ± 13° from vertical at baseline and 20 ± 12° at 2 years (p = not statistically significant). More than 90% of angle measurements showed <15° movement over the follow-up duration. There was a small but significant superior pump migration from a depth of 12.7 ± 2.7 cm to 10.4 ± 2.6 cm (p < 0.001). There were no cannula obstructions or instances of right ventricular assist device use. The 30-day operative mortality was 3.0%. Prolonged inotrope dependence occurred in 5.3% (7 of 126) of patients, and low rates of pump thrombosis of 0.018 event/patient-year (0 at 3 months) and stroke 0.074 event/patient-year were noted.

Non-invasive radiographic measurements of surgical pump placement designed to avoid pump and cannula malposition demonstrate stable position with minimal pump migration.