Temporary Neurological Dysfunction After Minimal Invasive Mitral Valve Surgery: Influence of Type of Perfusion and Aortic Clamping Technique

Abstract

Neurological injuries after cardiac surgery are serious complications in terms of clinical outcome and cost-effectiveness [1Cheng D.C. Martin J. Lal A. et al.Minimally invasive versus conventional open mitral valve surgery: a meta-analysis and systematic review.Innovations (Phila). 2011; 6: 84-103Crossref PubMed Scopus (227) Google Scholar, 2Mazine A. Pellerin M. Lebon J.S. Dionne P.O. Jeanmart H. Bouchard D. Minimally invasive mitral valve surgery: influence of aortic clamping technique on early outcomes.Ann Thorac Surg. 2013; 96: 2116-2122Abstract Full Text Full Text PDF PubMed Scopus (37) Google Scholar]. In the current scenario of an increasing spreading of minimal invasive mitral valve surgery (MIMVS), the role of specific clamping techniques and perfusion strategies on the occurrence of this complication is still matter of discussion. Several surgical settings have been reviewed without general agreement on the safest technique to adopt: retrograde arterial perfusion (RAP) with fibrillating or beating heart, RAP with transthoracic clamp (P+XC), RAP with Endoreturn/Intraclude (Edwards Lifesciences, Irvine, CA) system (P+EB), and antegrade arterial perfusion with the Endodirect (Edwards Lifesciences, Irvine, CA) system (C+EB). In a recent study, we evaluated 460 consecutive patients who underwent MIMVS. Our analysis showed that with a proper preoperative assessment and allocation to the most appropriate setting, the rates of early mortality and stroke were low and comparable between the different strategies performed [3Barbero C. Marchetto G. Ricci D. et al.Right minithoracotomy for mitral valve surgery: impact of tailored strategies on early outcome.Ann Thorac Surg. 2016; 102: 1989-1995Abstract Full Text Full Text PDF PubMed Scopus (29) Google Scholar]. However, neurological injuries can also occur as minor neurological dysfunctions (MND). These are temporary neurological impairments with negative computed tomographic-scan and apparently complete recovery before discharge, but theoretically capable of determining long-term cognitive and intellectual deficits [4Centofanti P. Barbero C. D’Agata F. et al.Neurologic and cognitive outcome after aortic arch operation with hypothermic circulatory arrest.Surgery. 2016; 160: 796-804Abstract Full Text Full Text PDF Scopus (19) Google Scholar]. MND are more common than strokes in the postoperative period, thus providing a greater statistical power able to highlight differences between surgical techniques. We report an additional retrospective analysis of the same cohort of patients in the same study period focusing on MND. Overall, total neurological complications were 4.9% (22/451), whereas major and minor neurological events were 1.5% (7/451) and 3.3% (15/451), respectively. The subgroup analysis showed significant differences regarding the MND rate: 12 cases were reported in the P+EB group (5%) versus 3 cases in the C+EB group (4.8%), and no cases in the P+XC group (p = 0.02). No subgroup differences regarding total and major neurological events were reported. Logistic regression analysis showed no correlation between MND and perfusion or aortic clamping techniques and highlighted that patients without peripheral vascular disease had a protective factor against MND (odds ratio, 0.044; 95% confidence interval, 0.005–0.378). This further analysis confirms that, in our experience, when MIMVS is based on a proper patient preoperative evaluation and matching with the safest approach, the rate of neurological complications—also including MND—remains favorable. Despite subgroup retrospective analysis showing that P+EB is associated with an increased risk of MND, this is not corroborate by the logistic regression analysis. However, our clinical retrospective experience did not make it possible to determine exactly the safest technique to adopt, and additional data are required to clarify this issue. Prospective, randomized studies comparing different modes of perfusion and aortic clamping techniques, using more sensible and precise diagnostic tools should be taken in consideration to highlight even the subclinical neurological complication after MIMVS.