What is the role of septal myectomy in aortic stenosis?

Asymmetric basal septal hypertrophy is present in 10% of patients with hemodynamic significant aortic valve stenosis. From the surgeon's standpoint, it represents a dilemma as it may be implicated in suboptimal short and long-term results after aortic valve replacement (AVR), but also heighten unwarranted complications at the time of surgical correction. To provide insight about the usefulness and safety of concomitant septal myectomy in this setting, we performed a literature review searching Medline from its inception to November 2020 using the Pubmed interface. Only five low evidence retrospective analyses, comprising a total of <200 patients undergoing AVR with concomitant septal myectomy, were found in the literature. In summary, routine myectomy, in the presence of suspected or directly visualized asymmetric septal hypertrophy on echocardiogram during AVR, seems to be a safe procedure, with all authors reporting a low rate or absence of complications. Overall, myectomy in this setting is associated with superior echocardiographic results concerning surrogates of LV remodelling (LVM; LVM index; LVM/height) and diastolic function (E/E'), suggesting some benefit for hemodynamic outcomes. However, to what extent hemodynamic improvement is exclusively attributable to myectomy is uncertain, as is, the clinical significance of such an improvement, with similar short and mid-term survival rates being reported.

In low-risk patients aged >70-75 with severe aortic stenosis, is transcatheter superior to surgical aortic valve replacement in terms of reported cardiovascular composite outcomes and survival?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: In low-risk patients aged >70-75 with severe aortic stenosis, is transcatheter superior to surgical aortic valve replacement in terms of reported composite outcomes and survival? More than 73 papers were found using the reported search, of which 8 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers were tabulated. The only low-risk randomized control trial to date [Nordic Aortic Valve Intervention (NOTION)] regarding an elderly population did not show a statistically significant difference between the 2 approaches regarding the composite endpoint of death, stroke or myocardial infarction. A subgroup analysis of elderly patients in the 2 main low-risk randomized control trials did not yield statistically different results from those of the overall population; the results indicated the superiority of transcatheter aortic valve implantation regarding the composite of death, stroke or rehospitalization at 1 year [The Safety and Effectiveness of the SAPIEN 3 Transcatheter Heart Valve in Low Risk Patients With Aortic Stenosis (PARTNER 3)] and non-inferiority regarding a composite of death or stroke at 2 years [Medtronic Evolut Transcatheter Aortic Valve Replacement in Low-Risk Patients (Evolut LR)]. The results from lower evidence studies are largely consistent with these findings. Overall, there is no compelling evidence indicating that older age should be an isolated criterion for the choice between transcatheter aortic valve replacement and surgical aortic valve replacement in otherwise low-risk patients. The superiority of either technique regarding the aforementioned composite short-term outcomes in this particular subgroup of patients is unclear.

Are NOACs as safe and efficient as VKA regarding thromboembolic prophylaxis and major bleeding in patients with surgical bioprosthesis and atrial fibrillation within 3 months of surgery?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: 'Are NOACs as safe and efficient as vitamin K antagonist regarding thromboembolic prophylaxis and major bleeding in patients with surgical bioprosthesis and atrial fibrillation within 3 months of surgery?' Altogether more than 324 papers were found using the reported search, of which 6 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. The RIVER and ENAVLE trials showed non-inferiority of rivaroxaban (regarding mean time free from composite of death, major cardiovascular events or major bleeding at 12 months) and edoxaban (composite of death, clinical thromboembolic events or asymptomatic intracardiac thrombosis; and major bleeding) when compared with vitamin K antagonist. These studies include a low number of patients within 3 months of index surgery and overall low statistical power regarding this particular subgroup of patients. Data derived from lower evidence studies are compatible with the aforementioned findings. The available evidence suggests that non-vitamin K antagonist anticoagulants are as safe and as efficient as vitamin K antagonist regarding thromboembolic prophylaxis and bleeding event rates in patients with surgical bioprosthesis and atrial fibrillation within 3 months of bioprosthesis implantation. However, this evidence is derived from a limited number of studies with important methodological limitations. Expanding non-vitamin K antagonist anticoagulant recommendation to the early postoperative period warrants more confirmatory research.

Does routine topical antimicrobial administration prevent sternal wound infection after cardiac surgery?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was 'Does routine topical antimicrobial administration prevent sternal wound infection (SWI) after cardiac surgery? Altogether >238 papers were found using the reported search, of which 11 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Several different antimicrobial agents, dosages and application protocols were found in the literature. Regarding topical vancomycin use, a meta-analysis by Kowalewski et al. demonstrated a 76% risk reduction in any SWI. Collagen-gentamicin sponge application was associated with a 38% risk reduction in SWI in another meta-analysis by Kowalewski et al., which included 4 randomized control trials and >23 000 patients. Lower evidence observational studies found benefit in the use of different regimes, including: combination of vancomycin paste and subcutaneous gentamycin; combined cefazoline and gentamicin spray; isolated cefazolin; bacitracin ointment; and rifampicin irrigation. We conclude that, in light of the body of evidence available, topical antibiotic application prevents SWI, including both superficial and deep SWI. The strongest evidence, derived from 2 meta-analyses, is related to the use of gentamicin-collagen sponges and topical vancomycin. Heterogeneity throughout studies regarding antibiotic agents, dosages, application protocols and SWI definition makes providing general recommendations challenging.

Cold Agglutinins and Cardiac Surgey: a Case Report.

Cold agglutinins (CA) are autoantibodies whose clinical significance depends upon titer and thermal amplitude. Patients, which undergo cardio-pulmonary bypass and especially hypothermic cardioplegia myocardial protection, represent a challenge regarding operative management, as tissue temperature should be maintained above the threshold of agglutination. We report on a case in which the presence of CA was discovered during elective aortic valve replacement surgery, and managed with normothermic cardiopulmonary bypass and continuous retrograde warm blood cardioplegia administration.