McCarthy S, Molina E, Nemeh H, Chaudhry S, Pinney S, Srivastava A, Grinstein J, Hackett I, and Cowger JA. Characterizing Outflow Graft Narrowing over Time. J Heart Lung Transplant 2022; 41(4):S138.
J Heart Lung Transplant
Purpose: Cases of pump dysfunction due to outflow graft (OG) anastomosis obstruction related to serous fluid accumulation have been reported but the rate of occlusion and actual frequency of asymptomatic OG diminution is not known.
Methods: This was a multicenter retrospective analysis of patients on HeartMate II (HMII) or HeartMate 3 (HM3) support surviving at least 180 days with at least one chest computed tomography (CT) scan at 6 months, 1, 2, and/or 3 years postoperative. Patients with OG obstruction due to torsion were excluded. The outflow graft (OG) diameter was measured at its narrowest region; region was categorized as external outflow graft (EOG), mid-graft, or within 2 cm of the aortic anastomosis. Mixed models with repeated measure linear regression was used to assess OG diameter change over time, with 14 mm as reference. Using the narrowest measure, OG diameter was modelled for freedom from death, admission for HF and low flow alarms with hazard ratio [95% CI presented].
Results: Of 71 patients included herein, 25% and 75% were on HMII and HM3 support for a median [25th, 75th] 1230 [703,1592] days. The median CT count was 2 [1,2] per patient. At follow-up, small (1-3 mm, table), but statistically significant reductions in OG diameter were noted (Figure). The median OG narrowing was 7% [0%, 20%]. Time from device implant was the most significant contributing factor (p<0.001) while wrapping of the outflow was nonsignificantly correlated with OG narrowing (p=0.071). Device model was not correlative (p=0.16). OG diameter was not correlated with survival (HR 1.04 [0.81-1.3]), stroke (HR 0.94 [0.78-1.1]) or admissions for heart failure (HR 1.06 [0.88-1.3]), or VAD alarms (HR 0.93 [0.79-1.1]).
Conclusion: Minor narrowing of the OG was noted over time, irrespective of LVAD model. The observed degrees of non-twist related-OG narrowing herein did not lead to increase mortality or events. OG wrapping may be associated with OG narrowing over time. Larger sample analyses aim to define degrees of narrowing that elicit device dysfunction.