Abstract
Aortic insufficiency (AI) is an important adverse event in patients with continuous-flow (CF) left ventricular assist device (LVAD) support. AI is often progressive, resulting in elevated 2-year morbidity and mortality. The effectiveness of echocardiographic ramp studies in patients with AI has been unclear. Here, we describe a patient with a CF-LVAD implant who underwent aortic valve replacement (AVR), following assessment of AI using a hemodynamic ramp test with simultaneous echocardiography and right heart catheterization (RHC). The patient was a 21-year-old man with cardiogenic shock due to acute myocarditis, who underwent HeartWare CF-LVAD (HVAD) implantation. Heart failure persisted despite increased doses of diuretics and inotrope, as well as an increased HVAD pump rate. HVAD monitoring revealed a correlation between increased HVAD pump rate and flow at each speed step. A hemodynamic ramp test with simultaneous transthoracic echocardiography and RHC revealed a significant discrepancy between HVAD pump flow and cardiac output (CO) at each speed step; moreover, pulmonary capillary wedge pressure remained high. Therefore, the patient underwent AVR. Subsequently, his low CO symptoms disappeared and inotropes were successfully discontinued. A postoperative hemodynamic ramp test revealed that AVR had successfully closed the loop of blood flow and reduced the discrepancy between HVAD pump flow and CO, thereby increasing CO. The patient was then discharged uneventfully. In conclusion, a hemodynamic ramp test with simultaneous echocardiography and RHC was useful for the evaluation of the causal relationship between AI and low CO, and for selection of surgical treatment for AI in a patient with CF-LVAD.
Highlights
Aortic insufficiency (AI) is an important adverse event in patients with continuous-flow (CF) left ventricular assist device (LVAD) support [1]
The hemodynamic ramp test revealed only slight reduction in left ventricular end-diastolic dimension (LVEDD) for each speed increase of − 0.00081 cm/increment [6], as well as a discrepancy between HeartWare CF-LVAD (HVAD) pump flow and cardiac output (CO) (3.05 vs 3.7 L/min at 2,400 rpm and 3.48 vs 5.7 L/min at 3400 rpm) (Table 1a and Fig. 1a). We presumed that this discrepancy between HVAD pump flow and CO was caused by blood returning to the left ventricle through the insufficient aortic valve
A severely regurgitant aortic lesion enables greater equalization of pressure between the aorta and left ventricle, compared with normal heart, thereby minimizing the pressure gradient and increasing the HVAD pump flow [7]. This increased HVAD pump flow does not match the increase in CO, because some amount of blood perfused by the HVAD returns to the left ventricle by a low-resistance circuit through the regurgitant aortic valve
Summary
Aortic insufficiency (AI) is an important adverse event in patients with continuous-flow (CF) left ventricular assist device (LVAD) support [1]. The hemodynamic ramp test revealed only slight reduction in LVEDD for each speed increase of − 0.00081 cm/increment [6], as well as a discrepancy between HVAD pump flow and CO (3.05 vs 3.7 L/min at 2,400 rpm and 3.48 vs 5.7 L/min at 3400 rpm) (Table 1a and Fig. 1a). We presumed that this discrepancy between HVAD pump flow and CO was caused by blood returning to the left ventricle through the insufficient aortic valve. The patient was discharged uneventfully on his 165th day of hospitalization
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