HVAD to HeartMate 3 Left Ventricular Assist Device Exchange: Best Practices Recommendations

Outcomes After Heartmate 3 Left Ventricular Assist Device Implantation Using a 10 mm Outflow Graft

The presence of adhesions and patent bypass grafts may create challenges for standard 14 mm outflow graft placement during left ventricular assist device implantation. We retrospectively describe our experience using a 10 mm Bioline Fusion graft (Getinge, Goteborg, Sweden) as the outflow graft in patients undergoing primary Heartmate 3 (Abbott, Abbott Park, IL) implantation. One hundred one patients underwent Heartmate 3 left ventricular assist device implantation, 80% via a thoracotomy approach, with the standard 14 mm outflow graft (78) or a 10 mm Bioline Fusion outflow graft (23). Initial postoperative rotor speed-to-flow ratio (the revolutions per minutes (RPMs) required to achieve a given flow) was significantly higher in 10 mm graft patients (1,472 vs. 1,283 RPM/L/min; p = 0.03), suggesting elevated resistance in the smaller graft. Furthermore, the initial postoperative vasoactive-inotrope score was higher in the 10 mm graft patients (24.1 vs. 17.6; p = 0.022). Postoperative outcomes were similar between groups. In conclusion, the use of a 10 mm graft was associated with higher RPMs needed to generate a given flow and a higher vasoactive-inotrope score, but these differences were not associated with increased right ventricular failure or mortality.

Turbulent flow field in maglev centrifugal blood pumps of CH-VAD and HeartMate III: secondary flow and its effects on pump performance

Secondary flow path is one of the crucial aspects during the design of centrifugal blood pumps. Small clearance size increases stress level and blood damage, while large clearance size can improve blood washout and reduce stress level. Nonetheless, large clearance also leads to strong secondary flows, causing further blood damage. Maglev blood pumps rely on magnetic force to achieve rotor suspension and allow more design freedom of clearance size. This study aims to characterize turbulent flow field and secondary flow as well as its effects on the primary flow and pump performance, in two representative commercial maglev blood pumps of CH-VAD and HeartMate III, which feature distinct designs of secondary flow path. The narrow and long secondary flow path of CH-VAD resulted in low secondary flow rates and low disturbance to the primary flow. The flow loss and blood damage potential of the CH-VAD mainly occurred at the secondary flow path, as well as the blade clearances. By contrast, the wide clearances in HeartMate III induced significant disturbance to the primary flow, resulting in large incidence angle, strong secondary flows and high flow loss. At higher flow rates, the incidence angle was even larger, causing larger separation, leading to a significant decrease of efficiency and steeper performance curve compared with CH-VAD. This study shows that maglev bearings do not guarantee good blood compatibility, and more attention should be paid to the influence of secondary flows on pump performance when designing centrifugal blood pumps.

Acute Outflow Graft Occlusion-A Novel Predictable Complication of Lysis Therapy for the Treatment of Left Ventricular Assist Device Intra-Pump Thrombosis

Lysis therapy is an established treatment option for intra-pump thrombosis of left ventricular assist devices (LVADs). In clinical routine, we observed repeated cases of acute outflow graft occlusions (OGO) associated with lysis therapy with need for urgent intervention. The aim of this investigation was to gain understanding of this observation. We screened data of 962 HeartWare ventricular assist device (HVAD) patients. One hundred twenty (13.8%) had intra-pump thromboses; 58 were treated with recombinant tissue-type plasminogen activator (rtPA). Mean age was 53.0 ± 11.1 years; 84.9% were male. In 13 (24.5%) patients, OGO occurred following rtPA-lysis. These patients showed an increase in left ventricular function (18.45% ± 12.62% to 27.73% ± 10.57%; p = 0.056), more frequent 1:1 aortic valve opening (OGO+: +36.4%; OGO-: +7.4%; p = 0.026), a decrease in LVAD pulsatility within 12 months prior intra-pump thrombosis (OGO+: -0.8 L/min [interquartile range {IQR}, -1.4 to -0.4 L/min]; OGO-: -0.3 L/min [IQR, -0.9 to 0.1 L/min]; p = 0.038) and lower HVAD flows at admission (OGO+: 6.7 L/min [IQR, 6.1-7.4 L/min]; OGO-: 8.3 L/min [IQR, 6.9-9.3 L/min]; p = 0.013), indicating a subclinical OGO prior intra-pump thrombosis. There were no differences in implantation techniques, blood parameters, and lysis strategy. Subclinical OGO represented a major risk factor for acute OGO following rtPA lysis therapy. We here propose an algorithm for risk stratification and dealing with patients presenting this first-described complication. Further research is required to confirm our results and decipher the underlying pathomechanism. http://links.lww.com/ASAIO/B97.

Pathophysiology and Management of Heart Failure in the Elderly

The population of elderly adults is increasing globally. It has been projected that the population of adults aged 65 years will increase by approximately 80% by 2050 in the United States. Similarly, the elderly population is rising in other countries; a notable example being Japan where approximately 30% of the population are aged above 65 years. The pathophysiology and management of heart failure (HF) in this age group tend to have more intricacies than in younger age groups owing to the presence of multiple comorbidities. The normal aging biology includes progressive disruption at cellular and genetic levels and changes in molecular signaling and mechanical activities that contribute to myocardial abnormalities. Older adults with HF secondary to ischemic or valvular heart disease may benefit from surgical therapy, valve replacement or repair for valvular heart disease and coronary artery bypass grafting for coronary artery disease. While referring these patients for surgery, patient and family expectations and life expectations should be taken into account. In this review, we will cover the pathophysiology and the management of HF in the elderly, specifically discussing important geriatric domains such as frailty, cognitive impairment, delirium, polypharmacy, and multimorbidity.