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

TEVAR and EVAR, the unknown knowns of the cardiovascular hemodynamics; and the immediate and long-term consequences of fabric material on major adverse clinical outcome

This review discusses the impact of endovascular aneurysm repair on cardiovascular (CV) hemodynamics and the role of stent-graft material, i.e., polytetrafluoroethylene (PTFE) vs. polyester in post-procedural outcomes. Endovascular aneurysm repair has been widely employed in the last decades for thoracic and abdominal aneurysm repair. However, aortic endografts are stiff and alter the native flow hemodynamics. This failure to simulate the native aorta could lead to added strain on the heart, manifesting as increased left ventricular strain, higher pulse pressure, and congestive heart failure later. This could result in adverse CV outcomes. Also, evidence is mounting to support the implication of stent-graft materials, i.e., PTFE vs. polyester, in adverse post-procedural outcomes. However, there is an absence of level one evidence. Therefore, the only way forward is to plan and perform a randomised controlled trial to demonstrate the alterations in the CV hemodynamics in the short and long run and compare the available stent-graft materials regarding procedural and clinical outcomes. We believe the best solution, for now, would be to reduce the stented length of the aorta. At the same time, in the longer term, encourage continuous improvement in stent-graft materials and design.

Early Left Ventricular Global Longitudinal Strain Deterioration After Aortic Aneurysm Repair: Impact of Aortic Stiffness

PURPOSE

To associate the impact of aortic reconstruction using currently available grafts and endografts on pulse wave velocity in patients with abdominal aortic aneurysm (AAA) and to evaluate its effect on early cardiac systolic function indices.

MATERIALS AND METHODS

Seventy-three consecutive patients with AAA (mean age 70±8 years; all men) who underwent open (n=12) or endovascular repair (EVAR; n=61) were prospectively enrolled in an observational cohort study. Left ventricular global longitudinal strain (GLS; an important diagnostic and prognostic index of early systolic dysfunction) and carotid-femoral pulse wave velocity (cf-PWV) were estimated 1 week preoperatively, as well as at 1 and 6 months postoperatively.

RESULTS

A significant time effect was found for cf-PWV, which showed an increase at 1 month that remained through 6 months (p=0.007). Additionally, a deterioration in GLS values was revealed, with a significant change at 1 month that persisted 6 months later (p<0.001). No significant group effect was observed between EVAR and open repair (p=0.98), and there was no significant interaction (p=0.96). Notably, the difference in GLS between baseline and 6 months significantly correlated with the corresponding changes in cf-PWV (r=0.494, p<0.001).

CONCLUSION

AAA repair leads not only to an increase in aortic stiffness, as measured by the increase in pulse wave velocity, but also to reduced cardiac systolic function. Our findings highlight the need for a more intense cardiac surveillance program after aortic reconstruction. Further studies are needed to investigate how this may translate into long-term manifestations of cardiovascular complications and symptomatology.

Analysis of Echocardiographic Markers and Pulse Wave Velocities in a Patient Who Developed New Cardiac Symptoms after Implantation of an Aortic Endograft

Increased arterial stiffness has been related to altered cardiovascular hemodynamics, left ventricular hypertrophy, and a higher risk for cardiac events. Pulse wave velocity (PWV) has been used as a surrogate marker for arterial stiffness. Treatment of abdominal aortic aneurysms (AAAs) involves insertion of a rigid graft or endograft inside the arterial system which has been shown to increase arterial stiffness, but the cardiac implications of these alterations are mostly unknown. We report a case of a patient with a previous AAA surgical repair (>10 years ago) who developed a para-anastomotic pseudoaneurysm which was excluded with implantation of an endoluminal graft. From a cardiac perspective, this patient was asymptomatic and had a normal baseline preoperative evaluation. He had an initially high PWV (17 m/sec). Postprocedurally, the patient developed cardiac symptoms, and he underwent coronary angiography which indicated significant coronary artery disease, and he subsequently underwent bypass grafting. One week after the endovascular repair, the patient presented with an increased PWV at 21 m/sec. Echocardiographic indices were mostly unaltered (ejection fraction, left ventricular mass index, and left atrium volume index) compared with the preoperative evaluation, except for the global longitudinal strain which deteriorated from -25 to -21%. This case provides insight into hemodynamic alterations after implantation of an endograft which may result in deterioration of asymptomatic heart disease.

Shear wave elasticity imaging for residual endoleak and thrombus characterisation after endoleak embolisation following endovascular aneurysm repair: a canine animal study

BACKGROUND

To evaluate residual endoleak and thrombus organisation with shear wave imaging (SWI) after endoleak embolisation through an animal study.

METHODS

This prospective experimental study involved eight dogs with creation of 16 iliac aneurysms and type I endoleak after endovascular aneurysm repair (EVAR). Embolisation agents were injected into the sac to seal endoleak. SWI and colour flow Doppler ultrasound (DUS) were performed at implantation, one week, and one and three months after implantation; for three dogs, SWI and DUS were also performed six months after implantation. Digital subtraction angiography and contrast-enhanced computed tomography were performed at sacrifice. Macroscopic and histopathological analyses were processed to identify regions of interest (ROIs) for endoleak, fresh thrombus, organised thrombus and embolisation agent, where SWI elasticity moduli were compared.

RESULTS

At sacrifice, nine aneurysms had residual endoleak, while seven were sealed. Ten had a fresh and 15 had an organised thrombus. SWI was able to detect all endoleaks, including two cases undetected with DUS. Elasticity moduli of 0.2 kPa ± 0.1 kPa (mean ± SD), 9.5 kPa ± 3.3 kPa, 48.1 kPa ± 21.3 kPa and 44.9 kPa ± 23.7 kPa were found in the ROIs positioned in endoleaks, fresh thrombi, organised thrombi and embolisation agent, respectively. Elasticity values of endoleak and fresh thrombus were lower than those of organised thrombi and embolisation agent (p < 0.001). Stiffness of fresh thrombus at one week (8.7 kPa ± 3.6 kPa) increased at three months (30.2 kPa ± 13.8 kPa), indicating thrombus maturation (p < 0.001).

CONCLUSIONS

In a dog model of iliac EVAR, SWI was able to identify endoleak, thrombus maturation and embolising agents after endoleak embolisation.