Aortic atherosclerosis and epiaortic scanning

Aortic atherosclerosis and epiaortic scanning

1. Aortic atherosclerosis Epiaortic scanning Gayathri G

2. Introduction Aortic atherosclerosis is widely recognised as a strong risk factor for atheroembolic events and especially stroke, after cardiac surgery. The brain was the most common target organ (16%), followed by spleen(11%), kidney(10%) and pancreas(7%). More common after coronary than after valvular procedures .

3. EPIAORTIC ULTRASOUND – EAU Hand-held transducer is placed directly upon a surgically exposed aorta. Can identify the presence of atherosclerosis Guide the surgeon to alter their surgical technique to minimize degree of aortic manipulation

4. Why EAU? Conventional CABG involves significant manipulation of the ascending aorta. Aortic cannulation, Antegrade cardioplegia line cannulation Aortic clamping Construction of proximal aortic anastomoses for coronary grafting.

5. Why EAU? It could disrupt soft or calcified plaques in the wall of the aorta and embolize their contents The greater the degree of aortic manipulation, the greater the degree of cerebral embolization. Alterations in the surgical technique to avoid dislodgement of aortic atheroma can reduce the risk of embolization

6. ROLE OF ULTRASOUND OF THE AORTA TEE has a “blind spot” - the distal ascending aorta and proximal aortic arch Sites for aortic cannulation and aortic clamping, and consequently, adequate imaging of these sites is crucial.

7. BARRIERS TO THE ADOPTION OF ROUTINE EAU The belief that manual palpation is more accurate. Lack of familiarity with the use of ultrasound technologies and concern about not being “trained” in its use. Institutional or unit protocols, inter specialty conflicts, or personal psychological factors are generally prominent causes preventing surgeons from adopting these new technologies. Lack of USG Machine

8. Indications Patients at risk for embolic stroke History of cerebrovascular disease History of peripheral vascular disease Patients with evidence of aortic atherosclerosis or calcification by other imaging modalities .

9. ZONES OF AORTA- 6 zones doi:10.1016 / j.bpa.2009.02.005

10. Transducers EAU imaging should be performed using a high-resolution (>7 MHz) ultrasound transducer Linear array Phased array Matrix array Linear probe produces a rectangular image whereas phased and matrix array probes both produce wedge-shaped windows.

11. Transducers Must be inserted into a sterile sheath filled with either sterile saline or ultrasound transmission gel Some echocardiographers recommend the use of two sheaths to increase the margin of safety Warm sterile saline should also be used to fill the mediastinal cavity to enhance acoustic transmission.

12. Linear array transducers Scans both the anterior aortic wall (near field) and the posterior aortic wall (far field) . Because of larger footprint, slightly difficult to manipulate in small surgical fields. No need for stand off.

13. Entire left-to-right dimensions of the aorta may not fit in a single window

14. Phased and Matrix array probes Enables simultaneous imaging of the right and left aortic walls . Smaller footprint – greater maneuverability within the surgical field . Anterior aortic wall (near field) will not be completely imaged without a standoff. Usually pericardial cradle is filled with saline and the probe is held 1cm anterior to the aorta while scanning.

15. STANDOFF Standoff refers to the distance between the probe and the object of interest Because of the wedge shape of the image, if the transducer is placed directly on the aorta, the anterior aortic wall (near field) will not be completely imaged; only a small section will be displayed while the rest will be outside the sector. To capture the near field in its entirety, the transducer is held at some distance away from the aorta

16. Ascending aorta is divided into 12 areas: Anterior Posterior Left lateral Right lateral Within proximal, mid, and distal ascending aorta segments .

17. Ascending Aorta Proximal AA - from STJ to the proximal intersection of the RPA Mid AA - adjacent to RPA Distal AA- from distal intersection of RPA to the origin of innominate A

18. Views SAX view of the proximal ascending aorta, SAX view of the mid ascending aorta, SAX view of the distal ascending aorta, LAX view of the ascending aorta, LAX view of the proximal aortic arch. DOI: 10.1213/ ane.0b013e31816a6b4c

19. Measurements Maximal plaque height/thickness , Location of the maximal plaque within the ascending aorta , Presence of mobile components .

20. Katz Grade TEE findings I Normal to mild intimal thickening II Severe intimal thickening without protruding atheroma III Atheroma < 5mm protruding into lumen IV Atheroma > 5mm protruding into lumen V Atheroma of any size with mobile component.

21. The incidence of stroke varies widely depending on the surgical procedure: 1.9% for off-pump coronary artery bypass graft (CABG) surgery, 3.8% for on-pump CABG, 4.8% for aortic valve surgery, 8.8% for mitral valve surgery, and 7.4% for combined CABG and valve surgery Patients with stroke have significantly longer intensive care department stays, have a 5-fold increase in postoperative mortality,7 and are a significant financial burden on the health care system

22. Risk factors associated with perioperative stroke include advanced age, female sex, history of cerebrovascular disease and/or peripheral vascular disease, diabetes, hypertension, previous cardiac surgery, preoperative infection, urgent operation, cardiopulmonary bypass time of greater than 2 hours, need for intraoperative hemofiltration, transfusion requirement, and proximal aortic atherosclerosis or a calcified aorta

23. Kapetanakis et al Demonstrated in 7272 patients undergoing isolated CABG that by simply minimizing aortic manipulation, the incidence of stroke can be diminished by 50%

24. (J Thorac Cardiovasc Surg 2011;142:1499-506)

25. Conclusion OPCAB is superior with regard to risk-adjusted outcomes. There is no difference in the stroke rate when comparing on-pump CABG versus applying partial aortic crossclamping in OPCAB. Whenever a proximal anastomosis is needed, a no-touch technique should be applied, that is, using the HS device.

26. Isa Coskun , MD Yucel Colkesen , MD Orhan Saim Demirturk , MD Huseyin Ali Tunel , MD Riza Turkoz , MD Oner Gulcan , MD Tex Heart Inst J 2014;41(1):26-32)

27. 360 Patients 120 Study No touch tech 240 Control Conventional

28. Discussion Presumably, an SV graft anastomosed to the LIMA might be exposed to less pressure trauma or shear stress than a graft anastomosed to the ascending aorta. Mean and diastolic graft pressures of an SV graft anastomosed to the LIMA have been shown to be lower than those of an SV graft anastomosed to the ascending aorta .

29. Conclusion we conclude that the aortic no-touch technique with composite grafts might be a reasonable option in patients who have an atherosclerotic ascending aorta that cannot be clamped.

30. Conclusion No touch Aorta technique has shown significant reduction in neurological outcomes with almost equal incidence of other morbidities.

31. Thank you