Exploring the potential of rapid evaporative ionization mass spectrometry (Intelligent Knife) for point-of-care testing in aortic surgery

Abstract OBJECTIVES Many intraoperative decisions regarding the extent of thoracic aortic surgery are subjective and are based on the appearance of the aorta, perceived surgical risks and likelihood of early recurrent disease. Our objective in this work was to carry out a cross-sectional study to demonstrate that rapid evaporative ionization mass spectrometry (REIMS) of electrosurgical aerosol is able to empirically discriminate ex vivo aneurysmal human thoracic aorta from normal aorta, thus providing supportive evidence for the development of the technique as a point-of-care test guiding intraoperative surgical decision-making. METHODS Human aortic tissue was obtained from patients undergoing surgery for thoracic aortic aneurysms (n = 44). Normal aorta was obtained from a mixture of post-mortem and punch biopsies from patients undergoing coronary surgery (n = 13). Monopolar electrocautery was applied to samples and surgical aerosol aspirated and analysed by REIMS to produce mass spectral data. RESULTS Models generated from REIMS data can discriminate aneurysmal from normal aorta with accuracy and precision of 88.7% and 85.1%, respectively. In addition, further analysis investigating aneurysmal tissue from patients with bicuspid and tricuspid aortic valves was discriminated from normal tissue and each other with accuracies and precision of 93.5% and 91.4% for control, 83.8% and 76.7% for bicuspid aortic valve and 89.3% and 86.0% for tricuspid aortic valve, respectively. CONCLUSIONS Analysis of electrosurgical aerosol from ex vivo aortic tissue using REIMS allowed us to discriminate aneurysmal from normal aorta, supporting its development as a point-of-care test (Intelligent Knife) for guiding surgical intraoperative decision-making. </jats:sec

Outcomes of acute type A aortic dissection repair: Daytime versus nighttime.

ObjectiveWe sought to report our experience of repairing acute type A aortic dissection (ATAAD) over 21 years during in-hours versus out-of-hours before and after the establishment of specialized aortic service and rota.MethodsA retrospective analysis of all patients who had ATAAD repair between November 1998 and December 2019 in our center. In-hours were defined as 08:00 to 19:59 hours and out of hours were defined as 20:00 to 07:59 hours.ResultsA total of 286 patients underwent repair of ATAAD. Eighty operations took place during the prerota period (43 operations in hours, 37 out of hours) and 206 operations during the specialized rota period (110 in hours, 96 out of hours). There was no difference in 30-day mortality between the in-hours and out-of-hours groups in either the prerota (23.3% vs 32.4%; P = .36) or specialized rota periods (11.6% vs 11.5%; P = .94). Mean number of cases per year increased by 83% between the prerota and specialized rota periods. Thirty-day mortality reduced in both the in-hours (23.3% vs 11.6%) and out-of-hours (32.4% vs 11.5%) groups since introduction of the specialized aortic rota.ConclusionsOutcomes in repair of ATAAD during in-hours and out-of-hours periods are similar when operated on in a specialized unit with a dedicated aortic team. This emphasizes the current global trend of service centralization without particular attention to time of day to operate on such critical cohort patients

Time-dependent mechanical behaviour of the aortic chronic dissection flap.

ObjectivesThe transition of aortic dissection from acute to chronic is poorly understood. We examined time-dependent mechanical behaviour and biochemical properties of chronic dissection tissues.MethodsAorta samples were obtained from 14 patients with mixed aetiology who were undergoing elective surgery for chronic dissected aneurysms, ranging from 3 months to 15 years post-dissection. The tissue elastic modulus and tissue deformation following application of loading for 5 h were measured for the false lumen (FL), true lumen (TL) and flap (FP) tissues with a custom-indentation technique. Collagen, elastin and glycosaminoglycan levels were determined with established biochemical assays. Elastin fragmentation was graded from histological sections. The number of tissues characterized was as follows: FP (n = 10), TL (n = 5 for biomechanical testing, n = 8 for biochemical analysis, n = 8 for histological assessment) and FL (n = 4).ResultsTissues stiffness was highest in FP [59.8 (14.8) kPa] as compared with TL [50.7 (6.2) kPa] and FL [40.5 (4.7) kPa] (P = 0.023 and P = 0.006, respectively). FP [0.5 (0.08) mm] also exhibited reduced deformation relative to TL [0.7 (0.02) mm] and FL [0.9 (0.08) mm] (P = 0.003 and P = 0.006, respectively), lowest collagen concentration [FP: 40.1 (19.6) µg/mg, TL: 59.9 (19.5) µg/mg, P = 0.008; FL: 79.1 (32.0) µg/mg, P = 0.006] and the lowest collagen: elastin ratio [0.4 (0.1)] relative to the other tissues [TL; 0.6 (0.3), P = 0.006, FL; 1.5 (0.4); P = 0.003]. Significant elastin loss was evident in the FL-stained tissue sections whereas highly aligned, long fibres were visible in the FP and TL. A linear relationship was found between the stiffness, deformation and the time from the dissection event to surgical intervention for the FP. All data are presented as median (interquartile range).ConclusionsFP exhibited reduced time-dependent deformation and distinct biochemical properties relative to TL and FL irrespective of connective tissue disorder or the anatomical region of the dissection

Deep circumferential annuloplasty as an adjunct to repair regurgitant bicuspid aortic valves with a dilated annulus.

BACKGROUND: Failure to address the functional aortic annulus during bicuspid aortic valve (BAV) repair has led to early repair failures. The pathology of regurgitant BAV involves annular dilatation, which is more pronounced anteriorly and deep toward the muscular interventricular septum. In this study, we assessed the results of BAV repair using a strategy of deep circumferential annular support involving the septum in patients with a dilated annulus (>26 mm) and moderate to severe aortic regurgitation (AR). METHODS: Between February 1999 and June 2015, 100 patients with regurgitant (≥2+) BAV and a dilated ventriculoaortic junction (VAJ) (≥26 mm) underwent repair with an adjunctive circumferential annuloplasty (reimplantation procedure or ring). External root dissection to accommodate the annuloplasty was carried deep onto the anterior aspect of the interventricular septum. Follow up was complete in 96 patients, with a median follow-up of 31 months and a total of 362 patient-years. Cox regression analysis was used to predict recurrence of AR. RESULTS: The mean VAJ diameter was 30 ± 4 mm. Seventy-nine patients exhibited delayed prolapse of the anterior leaflet (conjoined right and left cusps in Siever type 1 or anterior cusp in Siever type 0), and 93 patients underwent reimplantation. In the entire study group, there were no in-hospital deaths, and only 1 patient had 2+ AR on discharge. There was 1 late noncardiac death. At 8 years, freedom from AR ≥2+ was 96.4% and freedom from reoperation was 96.8%. Higher preoperative AR grade, small graft size, and use of a ring were predictive of recurrent AR. CONCLUSIONS: Regurgitant BAVs with a dilated annulus display anterior cusp prolapse toward the septum. A deep circumferential annuloplasty may help maintain repair durability

Bicuspid valve aortopathy is associated with distinct patterns of matrix degradation

Objective To explore the micromechanical, biochemical and microstructural differences between BAV-A (bicuspid aortic valve aneurysm) and TAV (tricuspid aortic valve) idiopathic degenerative aneurysm (DA), compared to normal aorta. Methods Aortic tissue was obtained from patients undergoing aneurysmal repair surgery (BAV-A; n=15 and DA; n=15). Control tissue was obtained from aortic punch biopsies during coronary artery by-pass graft surgery (CABG; n=9). Nanoindentation was used to determine the elastic modulus (E) on the medial layer. Glycosaminoglycan (GAG), collagen and elastin levels were measured using biochemical assays. Verhoeff Van Gieson-stained cross-sections were imaged for elastin microstructural quantification. Results E was over 20% higher for BAV-A relative to control and DA (signifying a loss of compliance). No significance difference between control and DA were observed. Collagen levels for BAV-A (36.9±7.4μg/mg) and DA (49.9±10.9μg/mg) were higher compared to the control (30.2±13.1μg/mg). GAG and elastin levels were not significant between the groups. Elastin segments were uniform throughout the control. Aneurysmal tissues had less elastin segments close to the intima and adventitia layers. Both BAV-A and DA had elastin segments compacted in the media, however, elastin segments were highly fragmented in DA. Conclusion BAV-A has a greater loss of aortic wall compliance relative to DA and the control. Although elastin levels were equal for all groups, spatial distribution of elastin provided a unique profile of matrix degradation for BAV-A. Elastin compaction within the media of BAV-A may have resulted from the altered haemodynamic pressure against the wall, which could explain for the stiffness of the tissue