How to define minimally invasive mitral surgery? First, by a fast-track procedure Free

The greatest danger for most of us is not that our aim is too high and we miss it, but that it is too low and we reach it.

Michelangelo

Minimally invasive mitral valve surgery (MIMVS) is a procedure related to a highly standardized treatment of degenerative mitral pathologies mainly affecting the posterior leaflet. Although more than a dozen of different techniques are used for open mitral repair, MIMVS is based on 2 basic principles of repair, namely leaflet resection and placement of artificial chordae for the majority of the cases. This fact makes the surgical procedure highly standardized in each and every step. This is the main precondition for an exact planning and standardization of anaesthetic and analgesic protocols as well as the postoperative regime as mandated by the Enhanced Recovery After Surgery (ERAS) concept. Altogether the combination of MIMVS and ERAS is the typical model, which fulfils the SMART criteria for implementation of a quality improvement program; the target is Specific, Measurable, Attainable, Realistic and Time-phased.

Previous authors have already addressed most of the components mentioned above [1]. At the current issue of the Journal, Van Praet et al. [2] elaborate on the Measurement and Attainability of a ERAS in MIMVS by identifying factors for an unsuccessful fast-track course. The aim of the analysis is two-fold: first to detect patients who will not get the maximum out of the ERAS protocol and second to showcase potentially modifiable periprocedural factors related to the improvement of outcome.

ADVANTAGES OF ERAS IN MIMVS

The common denominator regarding the advantages of ERAS in the setting of minimally invasive cardiac surgery includes a significant reduction of pain and a decrease in hospital length of stay [3]. This may theoretically lead to improved quality of life at least in terms of physical components and pain, albeit this benefit remains to be proven. The effect is obviously more prominent in patients with a low comorbidity profile, as they seem to benefit the most from ERAS protocols. In theory, shorter hospitalizations can be related to less time for postoperative observation of the patients and therefore to increased risks. Nevertheless, the clinical practice shows exactly the opposite, namely that ERAS protocols are safe and effective [4]. To what extent the ERAS concept can be related to the avoidance of complications is still debateable. The evidence speaks for a positive effect of ERAS on the occurrence of perioperative complications after MIMVS.

ERAS FOR PATIENTS WITH COMORBIDITIES

Van Praet et al. demonstrate that in the subgroup of patients undergoing MIMVS for primary mitral regurgitation, advanced heart failure symptoms, pre-existing chronic kidney disease and coronary artery disease are independent predictors for ERAS failure. Does this finding really mean that patients with comorbidities are suboptimal candidates for a fast-track concept? This question should be answered under the light of a balance between longer operative times—usually needed for comorbid patients operated through minimal incisions—and the advantages of early extubation, mobilization and enhanced recovery. In this context, patients undergoing a combination of MIMVS and ERAS and succeeding in accomplishing the fast-track protocol are more likely to benefit also in terms of clinical outcome as compared to comorbid patients following conventional protocols. The authors of the current study excluded all patients with secondary mitral regurgitation and those a priori scheduled for mitral valve replacement. Consequently, there is no way to extrapolate the results for patients with anatomically complex mitral disease requiring replacement and patients with more advanced stage of disease requiring concomitant tricuspid repair. The assumption stated above is true as long as the clinical ERAS protocol or the postoperative complications are not compromised by longer operative times.

ERAS FOR PATIENTS WITH COMPLICATIONS

Another important finding of the study is related to the obvious negative effect of perioperative bleeding needing surgical revision on the efficacy of ERAS. This is mainly associated with the prolongation of ventilation time and ICU stay in almost 2/3 of the cases. Perioperative complications affecting clinical outcome other than bleeding were not found to be of relevance for ERAS failure probably due to the very low endogenous risk of a patient population with Carpentier’s type I and II mitral regurgitation. However, there are obvious complications (such as stroke, perioperative low output and myocardial infarction), which cannot be neutralized by means of a fast-track protocol. On the other hand, patients with pulmonary complications may benefit from early mobilization and fast-track concepts.

The possible interaction between MIMVS and ERAS is extremely important not only for the implementation of a program but also for improving surgical outcomes. Patients with low comorbidity profiles and simple valve pathology are probably the best candidates for starting an ERAS program for MIMVS [5]. The combination of minimal operative trauma, preserved integrity of the thoracic cavity and early mobilization contributes to an expedited pulmonary recovery and improved physical status which will presumably lead to a quick improvement in terms of quality of life. This is the first pillar of the hypothetical advantage of ERAS. The second one relates to the avoidance of pulmonary and systemic complications by reducing the risk of pulmonary infections, atelectasis and the risk of a generalized inflammatory reaction. This is of utmost importance, especially for more complex patients.

The fact that patients with a high comorbidity profile and those with impaired preoperative functional status benefit the most from a minimally invasive, fast-track protocol has been well demonstrated at the early phase of transcatheter valve interventions. The use of the MIMVS–ERAS concept seems to be extremely promising for high-risk patients too and the need for evaluation in clinical studies is obvious. In our opinion, the surgical community needs to support applications of ERAS in combination to minimally invasive concepts in low-complexity patients, as done by Van Praet et al. Indeed, this would set the threshold too low. More importantly, we need to set the pace for the expansion of the concept to patients with more complex pathologies and comorbidities aiming at the improvement of outcomes.

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