Early Aspirin Nonresponders Identification by Routine Use of Aggregometry Test in Patients With Left Ventricle Assist Devices Reduces the Risk of Pump Thrombosis.

Left ventricular assist device (LVAD) management is very challenging since many adverse events can occur in ongoing patients. Inadequate anticoagulation treatment can lead to life-threatening situations like ischemic stroke or pump thrombosis. The main intention of our study was to investigate if early identification of aspirin nonresponders by using aggregometry can improve anticoagulation management, reducing the risk of pump thrombosis. METHODS: From December 2010 to May 2018, 24 patients were implanted with a HeartMate II (HMII), 6 received a HeartWare HVAD system--full support VAD (HVAD), and 22 received a HeartMate III (HMIII). All patients were maintained with a target INR of 2.0 to 3.0. When the aggregometry test revealed a normal platelet function, 100 mg of aspirin were initiated. Only aspirin nonresponders were early identified by repeating the aggregometry after 7 days of aspirin administration. In acetylsalicylic acid nonresponder patients, 75 mg of clopidogrel was used, and the patients were tested again. Ticlopidine (250 mg) was used when clopidogrel was unsuccessful. RESULTS: Four patients required modification in antiplatelet therapy. Three patients (5%), 2 HVAD and 1 HMII, suffered from pump thrombosis. One patient died as a consequence of a large intracranial hemorrhagic event following thrombolytic treatment. One patient required a pump exchange; in 1 patient, thrombolytic infusion was conducted successfully. CONCLUSION: Reported rates of pump thrombosis at 12 months for patients implanted with commonly used LVADs were 6% to 12% for axial-flow pumps and 8% with centrifugal-flow devices. In our series, the reported 5% overall incidence of pump thrombosis encourages the routine use of an aggregometry test for early identification of aspirin nonresponders.

Pump Speed Optimization in Patients Implanted With the HeartMate 3 Device.

BACKGROUND: Pump speed optimization in patients implanted with a ventricular assist device represents a major challenge during the follow-up period. We present our findings on whether combined invasive hemodynamic ramp tests and cardiopulmonary exercise testing (CPX) can help optimize patient management. METHODS: Eighteen patients implanted with a HeartMate 3 (HM3) device underwent ramp tests with right heart catheterization (including central venous pressure [CVP], pulmonary artery pressure, pulmonary capillary wedge pressure [PCWP], and blood pressure) and echocardiography. Data were recorded at up to 4 speed settings. Speed changes were in steps of 200 revolutions/min (rpm). Evaluation of functional capacity by CPX was conducted according to the modified Bruce protocol. RESULTS: Only 30% of patients had normal PCWPs at their original rpm settings. In going from lowest to highest speeds, cardiac output improved by 0.25 ± 0.35 L/min/step (total change, 1.28 ± 0.3 L/min), and PCWP decreased by 1.9 ± 0.73 mm Hg/step (total change, 6 ± 1.6 mm Hg). CVP and systolic blood pressure did not change significantly with rpm. The rpm assessment was adjusted based on test results to achieve CVPs and PCWPs as close to normal limits as possible, which was feasible in all patients. On CPX, all patients demonstrated good performance (peak VO2, 16.8 ± 3.5 mL/kg/min). CONCLUSION: Hemodynamic ramp testing provides an objective means of optimizing rpm, and has the potential to provide good exercise tolerance.

Pulse Oximeter Usefulness for Blood Pressure Monitoring in Patients Implanted With Latest-Generation Continuous-Flow Device HeartMate 3.

INTRODUCTION: The measurement of blood pressure (BP) and the management of hypertension in patients with continuous-flow ventricular assist devices (CF-VADs) can present unique challenges. Patients with CF-VADs often do not have a palpable pulse, and therefore traditional blood pressure measurement by auscultation or automated cuff is less reliable. We tested the efficacy of blood pressure estimation using sphygmomanometry combined with finger pulse oximetry only after a hemodynamic optimization was effected to make the values estimated approximately similar to mean arterial pressure. METHODS: Fifteen consecutive patients with a mean age of 57.8 ± 11.2 years were implanted with HeartMate 3 between November 2015 and March 2017. All patients underwent pump speed optimization by conducting a ramp test during right heart catheterization. The patients were prospectively studied during the follow-up period and mean arterial pressure was estimated using 3 different methodologies: Doppler ultrasound, pulse oximeter, and automated blood pressure cuff. For each method 3 consecutive evaluations were conducted during 3 follow-up visits. RESULTS: For each patient, 9 different evaluations were obtained (3 for each method). The overall success rate was 100% for blood pressure assessment conducted with Doppler ultrasound and pulse oximeter and 80%-87% for automated monitor evaluations. The first 2 methodologies were 100% successful, while the third was 60% successful. Pearson's correlation analyses for the Doppler ultrasound and pulse oximeter measurements showed a good correlation when evaluations conducted with the same method were compared. A high variability emerged between estimations obtained by using an automated monitor and a poor correlation was found when this method was compared to the Doppler ultrasound and pulse oximeter measurements. CONCLUSION: According to our results, the pulse oximeter method showed a high success rate and a good correlation level with the standard procedure. Our data encourage the use of oximeters for domiciliary blood pressure assessment in patients implanted with a continuous flow device.