Preoperative Prediction of Aortic Insufficiency During Ventricular Assist Device Treatment

Abstract

SummarySurvival rate in patients with stage D heart failure has improved significantly owing to the development of continuous flow left ventricular assist devices (LVAD), but aortic insufficiency (AI) still remains one of the major unsolved complications that impairs patient quality of life. There are no established treatments for AI, and preoperative prediction and prevention of AI is needed. The opening of a native aortic valve (AV) is a sufficient condition for prevention of AI, and improvement of LV ejection fraction due to LV reverse remodeling (LVRR) is essential to open a native AV. Preoperative insufficient β-blocker treatment and pulsatile flow LVAD usage are keys for LVRR, opening of an AV, and prevention of AI. The second mechanism that leads to AI is remodeling of the aortic root and degeneration of a native AV, which results from reduced pulse pressure during LVAD support. Centrifugal or pulsatile flow LVAD usage has an advantage in terms of preserving pulsatility, and may prevent AI compared with an axial pump. There is less probability of avoiding AI with sufficient β-blocker treatment, and these patients may be good candidates for concomitant surgical intervention to a native AV at the time of LVAD implantation. (Int Heart J 2016; 57: 3-10)Key words: Pulsatility, VAD, Carvedilol, Aortic valve C urrently, the survival rate in patients with advanced heart failure (HF) has improved due to the development of continuous flow (CF) left ventricular assist device (LVAD) treatment and improvement of perioperative management procedures.1-9) However, quality of life during CF LVAD is still not satisfactory because of several unresolved postoperative complications. 4,10,11) One of the major complications is aortic insufficiency (AI), which is characterized as continuous aortic regurgitation during both systolic and diastolic phases through a degenerated and occasionally fusional native aortic valve (AV) ( Figure 1AB). 12,13) Native AV, which is apparently normal before LVAD implantation, can be associated with a considerable level of AI after LVAD implantation. Post-LVAD AI can develop even in the preoperative setting in which there is no aortic regurgitation at all. 12,14,15) In 2000, Rose, et al first documented acquired AV disease during pulsatile flow (PF) LVAD. They identified evidence of commissural fusion of native AV.16) In 2006, Frazier, et al summarized the relationship between commissural fusion of native AV and development of AI during CF LVAD treatment.17) We also showed that AI was more frequently observed in patients with CF LVAD as compared with PF pump in 2011 ( Figure 1C). 18) Since then, a number of single-center studies have documented a wide-ranging prevalence of AI during LVAD treatment. 15,[19][20][21] The development of AI during LVAD treatment is considered to be a multifactorial phenomenon and a result of altered AV and aortic root biomechanics due to chronic and continuous ventricular unloading. Unloading of LV results in ventricular decompression, and the combination of systolic ...

Aortic Insufficiency in LVAD Patients

“…Patient-related factors included pre-existing valvular dysfunctions, old age, and abnormal cardiac function. Pre-existing valvular dysfunctions include uncorrected mild AI [23,24], large aortic sinus diameters [6,25], LVADrelated factors include reduction of AV opening area and duration, high LVAD speed, and types of LVAD [6,25]. Previous studies have suggested that the higher rate of progressive AI with rotary LVAD support results from low pulsatility, which may induce a more significant regurgitant flow and a higher rate of valvular remodeling [22,[26][27][28].…”

The impact of uncorrected mild aortic insufficiency at the time of left ventricular assist device implantation

“…[4][5][6][7][8] Risk factors identified for AI progression include a lower frequency of aortic valve opening, aortic root diameter enlargement, longer LVAD support duration, older age, and the use of a continuous-flow pump, especially an axial flow pump. [5][6][7][9][10][11][12][13] Additionally, an animal study suggested that the outflow graft angle perpendicular to the aorta increased AI grade and recirculation. 14 However, studies have not found a significant association between AI after LVAD implantation and survival.…”