The development of aortic insufficiency in left ventricular assist device-supported patients

Abstract

Background: Aortic insufficiency (AI) following left ventricular assist device (LVAD) placement can affect device performance. The aim of this study was to examine AI development following LVAD implantation.

Methods and results: Echocardiograms (n=315) from 78 subjects undergoing HeartMate-XVE (n=25 [32%]) or HeartMate-II (n=53 [68%]) implantations from 2004 to 2008 were reviewed. Studies were obtained preoperatively and at 1, 3, 6, 12, 18, and 24 months after surgery. AI was graded on an interval scale (0=none, 0.5=trivial, 1=mild, 1.5=mild-moderate, 2=moderate, 2.5=moderate-severe, 3=severe), and the change in AI at follow-up was analyzed with significance tests. Kaplan-Meier estimates for freedom from moderate or worse AI at follow-up were generated. Mixed-model linear regression was used to identify correlates of AI progression during LVAD support. The median (25th, 75th percentile) duration of LVAD support was 239 (112, 455) days, and preoperative AI grade was 0.0 (0.0, 0.0). At 6 months, 89±4% of subjects (n=49 at risk) were free from moderate or worse AI, but this was reduced to 74±7% (n=29 at risk) and 49±13% (n=13 at risk) by 12 and 18 months, respectively. Correlates (slope±SE) of AI progression included female sex (0.002±0.001; P=0.01), smaller body surface area (-0.003±0.001 per m(2); P=0.0017), and HeartMate-II model type (0.002±0.001; P=0.039). Correlates (β±SE) of progressive AI on postoperative echocardiogram included increasing aortic sinus diameter (0.04±0.01 per mm; P=0.001), an aortic valve that remained closed (0.42±0.06; P<0.001) or only intermittently opened (0.34±0.09; P<0.001), and lower left ventricular diastolic (-0.002±0.0004 per cm(3); P<0.001) and systolic (-0.002±0.0004 per cm(3); P<0.001) volumes.

Conclusions: AI progresses over time in LVAD-supported patients. As we move toward an era of long-term cardiac support, more studies are needed to determine the clinical significance of these findings.

Figure 1

Box plot of aortic insufficiency grade. Insufficiency grades: 0=none, 0.5=trivial, 1.0=mild, 1.5=mild-moderate, 2.0=moderate, 2.5=moderate-severe, 3.0=severe. Thick horizontal line represents median.

Figure 2

Aortic insufficiency progression during LVAD support. Echocardiography images of aortic insufficiency a.) preoperatively and at b.) 9 months after HeartMate II implant are shown. The aortic insufficiency is continuous in systole and diastole.

Figure 2

Aortic insufficiency progression during LVAD support. Echocardiography images of aortic insufficiency a.) preoperatively and at b.) 9 months after HeartMate II implant are shown. The aortic insufficiency is continuous in systole and diastole.

Figure 3

Profile plot of aortic insufficiency for LVAD support subjects at follow-up. The overall trend in aortic insufficiency is shown for HeartMate-XVE (blue) and HeartMate-II (red) groups. AI grade as previously defined.