A 68-year-old man was admitted to the hospital 4 months after HeartMate II ventricular assist device implantation, because his clinical status had deteriorated and his levels of lactate dehydrogenase and free hemoglobin had increased. Transthoracic echocardiography performed at admission revealed decreased basic diastolic continuous flow velocity with a pulsatile increase in flow velocity during ventricular contraction in both inflow and outflow cannulas. Twelve hours after beginning lytic therapy, basal diastolic continuous flow velocity had increased, and the amplitude between diastolic and systolic flow velocity had decreased. The clinical status of the patient improved, and his lactate dehydrogenase decreased. A decrease in basal diastolic flow may be a valuable marker of flow disturbance in continuous flow ventricular assist devices.
Case Presentation
A 68-year-old man was admitted to our hospital 4 months after HeartMate II (Thoratec Corporation, Pleasanton, CA) continuous flow ventricular assist device implantation because his clinical status had deteriorated. His clinical course was uneventful until approximately 1 month before admission, when heart failure symptoms became apparent and a transient increase in the power consumption of the device was reported. Transthoracic echocardiography was performed repeatedly during this hospital stay: at admission, after medical treatment, after thrombolytic treatment, and prior to discharge. The outflow cannula could be examined from the second right parasternal intercostal space. The device data, laboratory findings, and selected echocardiographic measurements are presented in Table 1 . On the admission exam, the left ventricle was enlarged, and consistent partial systolic opening of the aortic valve was observed during systole (Figures 1 A and 2 B, Video 1 ). Mild aortic insufficiency was noted only during diastole, and high-grade mitral valve insufficiency was also present ( Figure 2 B, Video 2 ). No signs of inflow cannula malposition or thrombus could be seen. Color Doppler showed laminar flow in both inflow and outflow cannulas. Diastolic flow velocity in both cannulas was low, and large differences between basal diastolic and pulsatile systolic flow velocities were observed ( Figures 3 A and 3 B). The next examination, performed after the optimization of medical therapy and increasing the speed of the pump, did not differ significantly. Neither the transesophageal examination nor contrast-enhanced computed tomography improved the diagnosis. Because the patient’s clinical state did not improve, thrombolysis was performed. The patient’s condition improved rapidly, and 12 hours later, transthoracic echocardiography was performed. We noted a reduction in left ventricular diameter, and mitral insufficiency decreased. The aortic valve remained closed during systole, and aortic insufficiency was seen in both diastole and systole (Figures 1 B, 2 C, and 2 D, Video 3 ). We observed a change in the flow velocity pattern in both inflow and outflow cannulas ( Figures 3 C and 3 D, Video 4 ). Diastolic continuous flow velocity increased significantly, and the difference between diastolic and systolic flow velocity decreased. No important changes in mean arterial pressure were noted, as shown in Table 1 .
| Variable | At admission | After medical treatment | After thrombolysis | At discharge |
|---|---|---|---|---|
| Mean BP (mm Hg) | 70 | 68 | 71 | 75 |
| Rotation speed (rpm) | 9,200 | 9,600 | 9,600 | 9,400 |
| Free hemoglobin (mg/L) | 150 | 450 | 400 | 100 |
| LDH (U/L) | 2,700 | 3,243 | 1,152 | 900 |
| LV EDD (mm) | 69 | 68 | 56 | 58 |
| LV ESD (mm) | 65 | 61 | 49 | 55 |
| AV amplitude (mm) | 10 | 9 | 0 | 0 |
| LV ET (ms) | 170 | 135 | 0 | 0 |
| AI grade | I | I | I | I |
| AI | Diastole | Diastole | Diastole/systole | Diastole/systole |
| MI grade | III | III | I/II | I/II |
| Inflow diastole (cm/sec) | 40 | 20 | 70 | 60 |
| Inflow systole (cm/sec) | 70 | 80 | 138 | 140 |
| Outflow diastole (cm/sec) | 10 | 15 | 80 | 70 |
| Outflow systole (cm/sec) | 140 | 160 | 150 | 160 |
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