Preoperative vascular screening: a novel breakthrough in minimally invasive mitral valve surgery

Comment to “Antegrade and retrograde perfusion in minimally invasive mitral valve surgery with transthoracic aortic clamping: a single-institutio experience with 1632 patients over 12 years” by Murzi M. et al. (doi:10.1093/icvts/ivw370) We read with great interest the study by Murzi et al., and we congratulate the researchers for the noteworthy objective and results [1]. The authors reviewed their 12-year institutional experience evaluating the impact of retrograde arterial perfusion (RAP) versus antegrade arterial perfusion in a cohort of 1632 patients who underwent minimally invasive mitral valve surgery (MIMVS) with trans-thoracic clamp (TTC) and concluded that the use of RAP was associated with a higher incidence of neurological complications in patients older than 70 years with atherosclerotic burden. The correlation between peripheral vasculopathy and neurological events during RAP is well known in the literature [2]. In the present study, not all the patients enrolled received a full preoperative vascular screening (CT-scan or angiography). The protocol reported consisted of a preoperative echographic examination of the iliac-femoral axis followed by intraoperative trans-oesophageal echocardiographic scans of the thoracic aorta; only in patients older than 70 years or with a clear atherosclerotic burden, was a CT-scan performed. Therefore patient allocation to the antegrade or retrograde setting was not based upon strict anatomical indications in all cases, and the possibility cannot be excluded that a higher rate of stroke in the RAP group could be associated with a higher percentage of patients with peripheral vascular disease in that group. In contrast to the evolution of practice described over time by Murzi— a switch from peripheral cannulation to ascending aorta cannulation—we believe that the breakthrough in MIMVS is to identify and select the safest approach for the specific patient. In the case of significant vascular disease at angiography or CT-scan, RAP and balloon manipulation should be avoided and a direct ascending aorta or axillary artery cannulation should be considered as a first option; in case of normal aorto-iliac-femoral vessels, RAP and endoaortic clamp should not be consider risk factors for stroke [3]. A study published by our group on 460 consecutive patients who underwent MIMVS through 3 different approaches—RAP with TTC, RAP with endoaortic clamp (EAC), and direct aortic cannulation with EAC—showed that, after a full preoperative vascular screening and allocation to the most appropriate setting, no cases of aortic dissection were reported and early mortality and stroke rates were low and comparable between the different strategies; logistic regression modelling showed no influences of arterial perfusion and aortic clamping techniques on 30-day mortality and stroke [4]. A multicentre study on MIMVS with the EAC setting carried out by Casselman supported this suggestion with a stroke rate as low as 0.8% and no aortic dissections [5]. In the last years, perfusion strategies and aortic clamping techniques for MIMVS have continued to evolve; these different approaches must be performed within the context of a safe and complete program with surgeons developing capability and confidence in each technique. In this way individual anatomy and clinical history can be used to achieve the best possible clinical outcome. Definitely, mandatory inclusion of full preoperative vascular screening will help us to achieve optimal results in this challenging field.