Correction to: The lactate clearance calculated using serum lactate level 6 h after is an important prognostic predictor after extracorporeal cardiopulmonary resuscitation: a single-center retrospective observational study.

[This corrects the article DOI: 10.1186/s40560-018-0302-z.].

The lactate clearance calculated using serum lactate level 6 h after is an important prognostic predictor after extracorporeal cardiopulmonary resuscitation: a single-center retrospective observational study.

BACKGROUND: Serum lactate level can predict clinical outcomes in some critical cases. In the clinical setting, we noted that patients undergoing extracorporeal cardiopulmonary resuscitation (ECPR) and with poor serum lactate improvement often do not recover from cardiopulmonary arrest. Therefore, we investigated the association between lactate clearance and in-hospital mortality in cardiac arrest patients undergoing ECPR. METHODS: Serum lactate levels were measured on admission and every hour after starting ECPR. Lactate clearance [(lactate at first measurement - lactate 6 h after)/lactate at first measurement × 100] was calculated 6 h after first serum lactate measurement. All patients who underwent ECPR were registered retrospectively using opt-out in our outpatient's segment. RESULT: In this retrospective study, 64 cases were evaluated, and they were classified into two groups according to lactate clearance: high-clearance group, > 65%; low-clearance group, ≤ 65%. Surviving discharge rate of high-clearance group (12 cases, 63%) is significantly higher than that of low-clearance group (11 cases, 24%) (p < 0.01). Considering other confounders, lactate clearance was an independent predictor for in-hospital mortality (odds ratio, 7.10; 95% confidence interval, 1.71-29.5; p < 0.01). Both net reclassification improvement (0.64, p < 0.01) and integrated reclassification improvement (0.12, p < 0.01) show that adding lactate clearance on established risk factors improved the predictability of in-hospital mortality. CONCLUSION: In our study, lactate clearance calculated through arterial blood gas analysis 6 h after ECPR was one of the most important predictors of in-hospital mortality in patients treated with ECPR after cardiac arrest.

"Peninsula-style" transverse aortic arch replacement in patients with bicuspid aortic valve.

Although the optimal surgical treatment of the dilated aortic arch is controversial in patients with a bicuspid aortic valve, such exists in more than 70% of bicuspid aortic valve patients. Aortic wall histologic abnormalities are present from the aortic root to the distal arch regardless of aortic size. We describe a simple "peninsula-style" technique of transverse arch replacement used in conjunction with valve-sparing aortic root replacement for patients with a bicuspid aortic valve. This provides resection of the entire dilated thoracic aorta, preserving the arch branches in continuity with the proximal descending aorta.

Releasable annuloplasty ring insertion--a novel experimental implantation model.

OBJECTIVE: Experimental testing of annuloplasty ring (AR) effects requires a control group if the AR is implanted conventionally. Our goal was to develop a reversible AR insertion method that allows for beating heart assessment with and without an AR, providing the ability to evaluate the effects of an AR in the same animal (internal control). We tested the feasibility of this technique in an in vivo ovine model using four-dimensional (4-D) radiopaque marker tracking. METHODS: Before the operation, a rigid AR (Edwards Geoform, Edwards Lifesciences, Irvine, CA, USA) was prepared by stitching the middle parts of eight double-armed sutures evenly spaced through the ring fabric using a Spring Eye needle. The resulting loops were 'locked' with polypropylene sutures. In addition, two drawstring sutures were attached to the AR. Using cardiopulmonary bypass and cardioplegic arrest, 12 adult sheep had 16 radiopaque markers sewn to the mitral annulus. The AR was implanted by stitching the eight sutures equidistantly in a perpendicular direction through the mitral annulus. The sheep were transferred to the catheterisation laboratory and 4-D marker coordinates were obtained using biplane videofluoroscopy (60 Hz) with the AR inserted (Geo-AR). The locking sutures were then released, the AR was pulled up to the atrial roof using the drawstring sutures and another dataset was acquired (control). Maximum and minimum mitral annular areas (MAA(max), MAA(min)) during the cardiac cycle were derived from implanted markers. Data are provided from one representative animal. RESULTS: AR insertion and release were uneventful in all animals. Whereas the mitral annulus was dynamic in the control state (MAA(max): 9.0 cm(2), MAA(min): 7.8 cm(2)), mitral annular dynamics were abolished in the Geo-AR case (MAA(max): 6.2 cm(2), MAA(min): 6.0 cm(2)). CONCLUSIONS: This novel releasable AR implantation method is feasible and permits in vivo assessment of AR effects in the same heart. The new technique should facilitate experimental AR testing and promote the development of ARs based on physical criteria.

Characterization of mitral valve anterior leaflet perfusion patterns.

BACKGROUND AND AIM OF THE STUDY: Although previous histologic studies have demonstrated the presence of blood vessels in the anterior mitral leaflet (AML) and second-order chordae (SC), little is known of the pattern of leaflet perfusion. Hence, the pattern and source of AML perfusion was investigated in an ovine model. METHODS: Fluorescein angiograms were obtained in 17 ovine hearts immediately after heparinization and cardioplegic arrest, using non-selective left coronary artery (LCA) and selective left anterior descending (LAD), proximal, mid- and distal left circumflex (LCx) perfusion. Serial photographs using a flash/filter system to optimize fluorescence were obtained through a left atriotomy. RESULTS: The proximal half of the AML was seen to be richly vascularized. A loop of vessels was consistently observed in the mitral annulus and AML; these vessels ran along the annulus, extended to the sites of SC insertion, and created anastomoses between these insertions. The SC contributed to the AML perfusion and the anastomotic loop. Selective perfusion of the LAD or proximal LCx artery (ligated before the first obtuse marginal artery) did not perfuse the AML (n = 6). Perfusion of the mid- and distal LCx (n = 7) consistently supplied the AML via SC insertion sites and annular branches. CONCLUSION: The ovine AML is perfused by vessels that run through the SC and annulus simultaneously, and then create a communicating arcade in the leaflet. These vessels originate from the mid- and distal portions of the LCx. A loss of perfusion as a result of microvascular disease could have adverse implications. Derangements in the extensive vascular component of the mitral valve could be an important contributing factor to valve disease.