Transcranial Doppler Sound Detection of Cerebral Microembolism during Transapical Aortic Valve Implantation

Abstract

Objective: Transapical aortic valve implantation (TAVI) is a new method that might reduce the surgical risk of conventional surgical aortic valve replacement in very high-risk patients. Increased downstream microembolization is expected in transapical aortic valve implantation. However, whether it usually occurs, how often, and its clinical relevance are not known. We report the results of ultrasound microembolic signal detection in the middle cerebral artery during the procedure. Methods: Fifty patients (mean age: 80 ± 5 years; mean EuroSCORE: 36 ± 13 %) underwent transapical aortic valve implantation. Intraoperative transcranial Doppler (TCD) sound examination of both middle cerebral arteries (MCA) was used to identify high-intensity transient signals (HITS) and microembolic signals (MES) during seven phases of the procedure. Pre- and postoperative computed tomography of the brain and clinical neurological examinations were performed preoperatively and daily during the first postoperative week. Results: During the procedure, HITS [right MCA: 435 ± 922 (range 9–5765); left MCA: 471 ± 996 (range 24–6432)] and MES [right MCA: 78 ± 172 (range 1–955); left MCA: 62 ± 190 (range 2–1553)] were detected in all patients. Most of the MES were recorded during valvuloplasty [right MCA: 3 ± 5.6 (range 0–31); left MCA: 2 ± 4.9 (range 0–30)] and positioning of the prosthetic valve in the aortic position [right MCA: 6 ± 5 (range 0–22); left MCA: 2 ± 6.9 (range 0–38)]. Postoperatively, there were no clinical signs of new cerebral embolism. Conclusions: Cerebral microemboli were detected by intraoperative transcranial Doppler sound examinations in all patients during transapical aortic valve implantation. Most of the signals were detected during balloon valvuloplasty and delivery of the prosthetic valve.

heart valve surgery - transcranial Doppler sound - transcatheter aortic valve implantation - transapical aortic valve surgery - cerebral infarction - valves - stroke - cerebral infarction

References

• 1 Walther T, Simon P, Dewey T et al. Transapical minimally invasive aortic valve implantation: multicenter experience.  Circulation. 2007;  116 I240-I245
• 2 Walther T, Dewey T, Borger M A et al. Transapical aortic valve implantation: step by step.  Ann Thorac Surg. 2009;  87 276-283
• 3 Roques F, Nashef S A, Michel P et al. Risk factors and outcome in European cardiac surgery: analysis of the EuroSCORE multinational database of 19030 patients.  Eur J Cardiothorac Surg. 1999;  15 816-822
• 4 Consensus Committee of the Ninth International Cerebral Hemodynamic Symposium . Basic identification criteria of Doppler microembolic signals.  Stroke. 1995;  26 (6) 1123
• 5 Georgiadis D, Wenzel A, Zerkowski H R, Zierz S, Lindner A. Automated intraoperative detection of Doppler microembolic signals using the bigate approach.  Stroke. 1998;  29 (1) 137-139
• 6 Pasic M, Dreysse S, Drews T et al. Improved technique of transapical aortic valve implantation: “the Berlin addition”.  Ann Thorac Surg. 2010;  89 2058-2060
• 7 Goldstein L B, Samsa G P. Reliability of the National Institutes of Health Stroke Scale. Extension to non-neurologists in the context of a clinical trial.  Stroke. 1997;  28 (2) 307-310
• 8 Barbut D, Lo Y W, Gold J P et al. Impact of embolization during coronary artery bypass grafting on outcome and length of stay.  Ann Thorac Surg. 1997;  63 998-1002
• 9 Accola K D, Scott M L, Palmer G J et al. Surgical management of aortic valve disease in the elderly: a retrospective comparative study of valve choice using propensity score analysis.  J Heart Valve Dis. 2008;  17 355-364
• 10 Harrison M J, Pugsley W, Newman S et al. Detection of middle cerebral emboli during coronary artery bypass surgery using transcranial Doppler sonography.  Stroke. 1990;  21 1512
• 11 Spencer M P, Campbell S D, Sealey J L, Henry F C, Lindbergh J. Experiments on decompression bubbles in the circulation using ultrasonic and electromagnetic flowmeters.  J Occup Med. 1969;  11 238-244
• 12 Zurbrügg H R, Nachbur B, Althaus U. Duplex and transcranial sonography in the preoperative evaluation of cerebrovascular circulation before heart operations.  Helv Chir Acta. 1989;  56 49-52
• 13 Grosset D G, Georgiadis D, Kelman A W et al. Detection of microemboli by transcranial Doppler ultrasound.  Tex Heart Inst J. 1996;  23 289-292
• 14 Milano A, D'Alfonso A, Codecasa R et al. Prospective evaluation of frequency and nature of transcranial high-intensity Doppler signals in prosthetic valve recipients.  J Heart Valve Dis. 1999;  8 488-494
• 15 Grube E, Laborde J C, Gerckens U et al. Percutaneous implantation of the CoreValve self-expanding valve prosthesis in high-risk patients with aortic valve disease: the Siegburg first-in-man study.  Circulation. 2006;  114 1616-1624
• 16 Newman M F, Kirchner J L, Phillips-Bute B et al. Longitudinal assessment of neurocognitive function after coronary-artery bypass surgery.  N Engl J Med. 2001;  344 395-402