Case
Case 1; A 54 year-old female was admitted due to shortness of breath and persistent LVAD low flow alarm. Her initial surgery(HeartMate 3 insertion with mitral and tricuspid valve repair) was 2 years and 6 months prior to this presentation. The LVAD pump flow was 1.4L/minute with 5400 rpm on admission, which was significantly lower than the baseline(i.e. 4.0L/minute with 5400 rpm). An echocardiography revealed that the aortic valve was open with every beat with a dilated left ventricle. While lactate dehydrogenase(LDH) level was slightly elevated(256U/l), serum haptoglobin(145mg/dl) and indirect bilirubin(0.2mg/dl) were within normal range. A computed tomography angiography(CTA) showed significant outflow graft narrowing at the vicinity of the LVAD pump(Figure 1A,1B).
Case 2; A 38 year-old male presented with shortness of breath, abdominal distension, nausea and vomiting. He had had the initial HeartMate 3 implantation and mitral valve repair 1 year and 6 months before. His pump flow was slightly lower than his baseline, specifically 4.0L/minute with 6200 rpm on admission and 5.1L/minute with 6200 rpm as baseline. An echocardiography demonstrated that the aortic valve was open with every beat. Lab data showed that lactate dehydrogenase(LDH) level was elevated(425U/l), serum haptoglobin was low(36 mg/dl) and indirect bilirubin was elevated(3.1mg/dl). An outflow graft angiography was performed, which showed an apparent outflow graft twisting at the proximal portion of the outflow graft(Figure 1C) with a significant pressure gradient about 100mmHg at the twisting by a pull back pressure measurement(Figure 1D,1E).
Both cases were taken to the operating room with a diagnosis of outflow graft twisting/kinking. A subcostal approach was utilized to access directly to the proximal portion of the outflow graft. A reverse-J shape incision was made in the subcostal area and the outflow graft was exposed enough to access to the connection between the outflow graft and the device body. A Rultract retractor (Rultract Inc., Ohio) was used to lift the rib to obtain a reasonable exposure (Figure 2A). The bend relief was identified, the plastic frames of the bend relief were partially removed, and the bend relief was longitudinally opened to exposed the outflow graft. It was found that the outflow graft was twisted about 3-4 cm from the device connector (Figure 2B). While the bend relief was stuck to the surrounding tissue, the bend relief was detached from the connector using the HeartMate accessory instrument. Then, the connector was rotated in a direction for untwisting the outflow graft. A curved-up Rongeur forceps was helpful to rotate. In both cases, it required to rotate in a counter clockwise fashion in 120 degree to fix the twisting(Figure 2C,2D). Hemodynamics and LVAD parameters were immediately improved. We did not place an outflow graft clip given the risks to injure the surrounding structures during a dissection with a relatively limited exposure. The opening of the bend relief was covered with a Gore-Tex soft tissue patch(WL Gore & Assoc Inc, Flagstaff, Ariz). After decent hemostasis, the incision was closed in layers in the routine fashion. The postoperative course was uneventful. No recurrent issue has been noted for 4 months of the follow up period.