Background: We developed an automated rapid anastomotic device for HeartMate 3 (HM3) standard apical cuff to Left Ventricle (AC-LV) anastomosis. Tissue anchors and compression plates axially compress the apical cuff sewing skirt to the myocardium. A low-profile delivery tool with integrated targeting system deploys all tissue anchors synchronously. The fixation mechanism minimizes myocardial impact because it confines tissue engagement to the area under the apical cuff sewing skirt. In acute bovine experiments (n=5), HM3 AC-LV anastomoses took less than 1 minute and had excellent hemostasis that was maintained at inotrope-induced supraphysiologic stresses (LV pressures 210-247 mmHg). The purpose of this study was to demonstrate HM3 AC-LV anastomotic durability in chronic bovine implants. Methods: Three calves (weight range 105-123 Kg) underwent HM3 AC-LV anastomosis on the beating heart by lower partial sternotomy with our anastomotic device. Thereafter, cardiopulmonary bypass (CPB) was initiated (ACT >400 seconds), 2 cm. diameter full-thickness LV cores were removed using an Abbott coring tool, and a custom-made sintered titanium plug was inserted to occlude the apical cuff. CPB was weaned, and AC-LV anastomotic hemostasis was assessed qualitatively by Likert Scale (1=unacceptable, 2 = poor, 3 = average, 4 = good, 5 = excellent). Pericardial and bilateral pleural chest tubes (CT) were placed. Serial hematocrit (HCT) and CT outputs were recorded. Anticoagulation was IV heparin at 12 hours, then warfarin through necropsy. Necropsies (gross and microscopic) were done at 56, 57, and 62 days by an experienced independent pathologist. Tissue anchor and compression plate position stability were assessed by acute vs. chronic photograph comparisons. Results: Implants times were 17, 20, and 17 sec. CPB time range was 6-9 min. Acute hemostasis was Likert Scale 5 (excellent) in all cases. At 24 hours, HCT exceeded intra-operative baseline in all animals (range: +2% - +3%) and remained stable. Forty-eight-hour CT output range was 514-760ml. There were no transfusions. In all cases necropsy demonstrated minimal pericardial/pleural adhesions; dense fibrous implant incorporation; stable tissue anchor/compression plate positions; no pseudoaneurysms; concentric smooth fibrous scar at the core site epicardial surface to AC junction (see figure); and implant site histology comparable to manual anastomosis. Conclusion: Rapid automated HM3 AC – LV anastomosis was hemostatic and durable. Additional advantages are greatly reduced operative time; uniform implant technique; precise apical cuff implant site targeting; guaranteed clearance for HM3 pump coupling; facilitates minimal access implant; and minimized myocardial impact (facilitates implant in smaller hearts/ potential to improve recovery). With modifications other LVADs Apical Cuffs can be accommodated, and derivative access ports can facilitate intracardiac device delivery.Figure 1. Concentric smooth fibrous scar at core site epicardial-apical cuff junction