Pulse Wave Analysis after Treatment of Abdominal Aortic Aneurysms with the Ovation Device

Abstract

Ovation aortic stent-graft system is a new device for the endovascular treatment of Abdominal Aortic Aneurysms achieving fixation via a 35-mm long, rigid anchored suprarenal stent and sealing stent at the infrarenal level by a means of a polymer-filling pair of inflatable O-rings, which cause narrowing of flow lumen and regional stenosis. Thus, concerns have been raised regarding hemodynamic consequences associated with this new design. Our preliminary report showed no significant increase of aortic pulse wave velocity (aPWV) immediately after implantation of the ovation in 3 patients. We studied further the hemodynamic implications of the Ovation implantation in 6 patients for a follow-up of 6months. A brachial cuff-based automatic oscillometric device (Mobil-O-Graph; IEM, Stolberg, Germany) was used to perform noninvasively pulse wave analysis and stiffness estimation. Measurements were held preoperatively in 6 patients treated for abdominal aortic aneurysm, at the end of the first postoperative week, first and sixth postoperative month. Changes in systolic and diastolic blood pressure (cSyst, cDiast), heart rate, aPWV, augmentation index (AI@75), augmentation pressure (AP), and in the amplitude ratio of the reflected-to-forward pressure waves (reflection magnitude, RM) were recorded and compared. Significant change in any parameter was examined via analysis of variance repeated measures. The cSyst was 132±19.6, 127±17.63, 131.3±19.96, and 129.83±31.72mm Hg (P= 0.81) and cDiast was 88±10.58, 86.83±11.72, 89.83±16.01, and 98.5±24.56mm Hg (P= 0.40). The heart rate showed an increasing yet nonsignificant tendency (67±10.60, 75.1±8.63, 74.33±8.89, and 70.66±6.65 beats/min, 0.27). The aPWV remained constant (11.61±1.88, 11.6±1.74, 11.8±2.08, and 11.85±2.30m/sec, P = 0.79). Similarly, RM (71.16±9.94, 60.66±11.79, 61.5±14.47, and 64.5±3.78), AI@75 (33.83±12.25, 22.16±7.93, 27.83±11.23, and 19.5±14.72), and AP (18.33±10.36, 9.83±4.91, 11.5±9.22, and 12±15.08mm Hg) remained practically unaltered during the follow-up period (P value: 0.79, 0.25, 0.10, and 0.27), respectively. The implantation of the Ovation stent graft does not cause increase in aortic stiffness or in pulse wave reflection in the mid-period. The rationale of investigating noninvasively the impact of aortic stent grafts on the mechanical properties and the hemodynamic parameters should be encouraged because such findings may contribute to further development of newer endograft designs.