Duration Of Ischemia Research Articles

Mangled Extremity Severity Score in the Assessment of Extremity Injuries - Is it Reliable?

The mangled extremity severity score (MESS) was established 28years ago to decide performing an amputation in cases of limb trauma. It assigns points for 4 aspects of the injury: the extent of soft tissue and skeletal injury, limb ischemia and ischemic duration, shock, and age. A score of 7 or higher indicates that primary amputation is required. Thirty-one patients with MESS scores of 7 to 8 underwent limb salvage surgeries, with 13 limbs being saved and 18 limbs being amputated. Upper extremities trauma had a salvage rate of 62.5%, whereas lower extremity trauma had a salvage rate of 20%. MESS is not a sensitive predictor of amputation in upper limb trauma, but it is useful in lower limb injuries.

Active Vitamin D3 (Calcitriol) Increases Adipose Graft Retention in a Xenograft Model.

Autologous fat grafting, although broadly indicated, is limited by unsatisfactory retention and often requires multiple procedures to achieve durable outcomes. Graft survival is strongly influenced by the magnitude and duration of post-engraftment ischemia. Calcitriol is a pleiotropic, safe nutrient with cell-specific influence on viability and metabolic flux. Evaluate the efficacy of activated vitamin D3 (calcitriol) in improving grafting outcomes and examine its mechanisms. Lipoaspirate was collected for ex vivo culture (7 unique donors), in vitro bioenergetic analysis (6 unique donors), and in vivo transplantation (5 unique donors). Ex vivo samples were incubated for up to 2 weeks before extraction of the stromal vascular fraction (SVF) for viability or flow cytometry. SVF was collected for Seahorse (Agilent; Santa Clara, CA) analysis of metabolic activity. Human endothelial cell lines were utilized for analyses of endothelial function. In vivo, samples were implanted into athymic mice with calcitriol treatment either (1) once locally or (2) 3 times weekly via intraperitoneal injection. Grafts were assessed photographically, volumetrically, and histologically at 1, 4, and 12 weeks. Hematoxylin and eosin (H&E), Sirius red, perilipin, HIF1α, and CD31 tests were performed. Calcitriol-treated lipoaspirate demonstrated dose-dependent increases in SVF viability and metabolic reserve during hypoxic stress. Calcitriol treatment enhanced endothelial mobility ex vivo and endothelial function in vitro. In vivo, calcitriol enhanced adipocyte viability, reduced fibrosis, and improved vascularity. Continuous calcitriol was sufficient to improve graft retention at 12 weeks (P < .05). Calcitriol increased fat graft retention in a xenograft model. Calcitriol has potential to be a simple, economical means of increasing fat graft retention and long-term outcomes.

Our Finger Replantation Results in the SARS-COV-2 Pandemic

Purpose: Finger injuries are important causes of emergency department admissions. In order to perform daily activities, the fingers must work fully and flawlessly. Replantation surgery aims to keep the injured finger alive and perform its functions almost completely. Our study aims to evaluate the reasons affecting the success of replantation during the SARS COV-2 pandemic period and to question the functional recovery after replantation. Methods: Finger and hand replantation performed in a single center by the same surgeon were reviewed retrospectively. Preoperative, intraoperative, and postoperative and demographic data of the patients, mechanism of injury, ischemia duration, complications, surgical treatment approaches, and functional evaluation scales after rehabilitation were collected and statistically evaluated. Results: In our study, 88 fingers of 56 patients were replanted. While single finger replantation was performed in 38 patients, multi-finger replantation was performed in 18 patients. The total success rate of replantation was 73.2%. While successful results were obtained in 81.6% of 38 patients with single finger replantation, 55.6% of 50 fingers in 18 patients with multiple finger replantation were successful. We found that 3 patients after surgery and 11 patients in the six months before surgery were positive for SARS COV-2. No finger loss or complications occurred in these 14 patients after replantation. Conclusion: We concluded that SARS COV-2 disease had no significant effect on finger replantation surgery. Our study found that the most important variables affecting surgical success were the mechanism of injury, injury level, age, gender, anesthesia technique applied, number of repaired veins, smoking, and ischemia duration.

A comparative study of digital nerve and digital arterial repairs performed using running versus interrupted suture techniques in finger replantations.

The present study aimed to retrospectively analyze replantations and compared the success rates of different suturing techniques. The data of 54 patients who underwent 82 finger replantations between January 2016 and April 2020 were retrospectively analyzed. Patients who underwent traumatic total finger amputations were included in the study. Arteries were repaired with two techniques, the simple running suture technique and the simple interrupted suture technique. Demographic patient data, comorbidities, operative data, post-operative care, the length of hospital stay, mechanism of injury, and site of injury were recorded. The groups were statistically analyzed. Functional outcomes were evaluated according to the Quick DASH score. A total 54 patients with a mean age of 32.5±18.4 (range 1-75) who underwent finger replantation were included in the study. The mean duration of follow-up was 30.9±16.1 months. The mechanism of injury was guillotine-style injury in 29 (35.4%) fingers, avulsion injury in 15 (18.3%) fingers, and crush injury in 38 (46.3%) fingers. Forty-six fingers were repaired using a simple running suture technique, and 36 fingers were repaired using a simple interrupted suture technique. There was no statistically significant difference in terms of failure between the suture techniques (p=0.569). Further, although there was no statistically significant difference in Quick DASH scores according to the type of trauma in the simple running suture technique group (p=0.109), a comparison could not be made within simple interrupted suture technique group because of the small sample size. There was no statistically significant difference in failure rates between cases with an ischemia duration of <6 h and those with ischemia duration of 6-12 h (p>0.05). No statistically significant difference was found between the groups according to age, body mass index, arterial hypertension, or diabetes mellitus (p>0.05). Statistically significant differences were found in univariate analysis according to surgery time per digit, smokers, or vein repair (p<0.05). In total, 65 (79.3%) out of 82 finger replantations were successful. A total of 17 out of 30 fingers that could not undergo venous repair survived because of treatment with medicinal leeches. Finger replantation is a difficult-to-perform surgical procedure requiring consideration of the surgical indications and the presence of an experienced surgical team. Regardless of the suture technique in finger amputations, performing venous anastomosis after arterial anastomosis is essential to restore circulation.

Outcomes of Surgical Revascularization for Acute Limb Ischemia in COVID-19 Patients Comparing to Noninfected Cohort: A Single-Center Observational Prospective Study

The purpose of the study was to compare the clinical presentation, management, and outcomes of surgical revascularization for acute limb ischemia (ALI) in 2 groups of patients-with and without SARS-CoV-2 infection. During the 2years (01.01.2020-31.12.2021) all consecutive patients diagnosed with ALI and treated with urgent revascularization were prospectively enrolled. Based on the results of polymerase chain reaction swab for SARS-CoV-2 infection patients were allocated to group A-infected or group B-noninfected. Demographic characteristics, clinical, imaging, laboratory data, and details of treatment were collected prospectively. The composite endpoint of major amputation and/or death at 30days after surgery was defined as main study outcome. The postoperative ankle-brachial index value, reinterventions, complications, and length of hospital stay were considered as secondary outcomes. Overall, 130 patients (139 limbs with ALI) were analyzed-21 patients (23 limbs) in group A and 109 patients (116 limbs) in group B. The anatomical site of arterial occlusion, duration, and severity of ischemia did not differ significantly between the groups. Patients with COVID-19 had significantly shorter time from ALI onset till administration of the first dose of anticoagulant: 8 (2.5-24) hr vs. 15.7 (6-72) hr in group B, P=0.02. Vascular imaging was performed before intervention only in 5 (23.8%) infected patients compared to 78 (71.5%) patients in group B, P<0.001. The main outcome was registered in 38 (29.2%) patients, significantly more frequent in infected cohort: 12 (57.1%) patients in group A versus 26 (23.8%) in group B, P=0.003. Difference was preponderantly caused by high mortality in group A-9 (42.8%) patients, compared to 17 (15.5%) patients in group B, P=0.01. The difference in the rate of limb loss was not statistically significant: 4 (17.3%) limbs were amputated in COVID-19 patients and 12 (10.3%) limbs-in noninfected patients (P=0.3). Combination of ALI and COVID-19 resulted in increased 30-day mortality-risk ratio (RR) 2.7 (95% confidence interval [CI]: 1.42-5.31), P=0.002, but did not lead to significantly higher amputation rate-RR 1.6 (95% CI: 0.59-4.75), P=0.32. In group A initial admission of the patient in the intensive care unit was an independent risk factor for amputation/death. Excepting systemic complications which were more frequently registered among COVID-19 patients: 7 (33%) cases vs. 14 (12.8%) in group B, P=0.04; no differences in other secondary outcomes were observed between the groups. Study demonstrates the significant negative impact of COVID-19 upon the 30-day amputation-free survival in patients undergoing urgent surgical revascularization for ALI. The difference in outcome is influenced by higher rate of mortality among infected patients, rather than by the rate of limb loss. Severity of COVID-19, namely requirement of intensive care, mostly determines the outcome of ALI treatment.

Impact of Blood Loss on Renal Function and Interaction with Ischemia Duration after Nephron-Sparing Surgery

Nephron-sparing surgery (NSS) exposes the kidney to ischemia-reperfusion injury. Blood loss and hypotension are also associated with kidney injury. We aimed to test the hypothesis that, during NSS, both ischemia duration and blood loss significantly affect postoperative renal function and that their effects interact. Consecutive patients undergoing NSS were enrolled. The primary endpoint was renal function expressed as the absolute delta between preoperative and postoperative peak creatinine. We developed a generalized linear model with the ischemia duration and absolute hemoglobin difference as independent variables, their interaction term, and the RENAL score. The model was than expanded to include a history of hypertension (as a proxy for hypotension susceptibility) and related interaction terms. Further, we described the perioperative and mid-term oncological outcomes. A total of 478 patients underwent NSS, and 209 (43.7%) required ischemia for a mean of 10.9 min (SD 8). Both the ischemia duration (partial eta 0.842, p = 0.006) and hemoglobin difference (partial eta 0.933, p = 0.029) significantly affected postoperative renal function, albeit without evidence of a significant interaction (p = 0.525). The RENAL score also significantly influenced postoperative renal function (p = 0.023). After the addition of a previous history of hypertension, the effects persisted, with a significant interaction between blood loss and a history of hypertension (p = 0.02). Ischemia duration and blood loss had a similar impact on postoperative renal function, albeit without potentiating each other. While the surgical technique and ischemia minimization remain crucial to postoperative kidney function, increased awareness of conscious hemodynamic management appears warranted.

The outcome of acute occlusion of the abdominal aorta with bilateral limb ischaemia

BackgroundThe purpose of this study was to investigate if the duration of bilateral acute limb ischaemia (BALI) caused by acute aortic occlusion (AAO) affected amputation-free survival. Materials and methodsA retrospective analysis of patients treated between 1 January 2010 and 1 January 2019 for primary occlusion of the infrarenal aorta and BALI was performed. Univariate analysis was used to determine the risk factors for adverse outcomes and compare the duration of BALI between the amputation-free survival and non-amputation-free survival groups. ResultsThe data from 16 patients with a mean age of 70 ± 11 years were analysed. Predominantly females (56.3%, 9/16) were included in the study. Out of 16 patients, nine had Rutherford grade IIb, and seven had Rutherford grade III at admission. Seven patients underwent revascularisation attempts, two underwent primary major amputation, and seven underwent primary palliation. The mean ischaemia time was significantly shorter in the amputation-free survival group than in the non-amputation-free survival group (7.4 ± 3.5 h vs 22.4 ± 16.3 h, p = .01). The time frame for successful bilateral lower limb revascularisation was <11 h (p = .03). ConclusionsThe duration of BALI due to AAO of <11 h was shown to be associated with improved amputation-free survival.

Abstract 13: Myocardial Metabolic And Electrolyte Derangements Linked To PEA Rearrest

Background: Cardiac rearrest after return of spontaneous circulation (ROSC) is a significant barrier to successful resuscitation, making it a high priority for emergency care research. Regardless of initial arrest rhythm, rearrest is commonly due to pulseless electrical activity (PEA). However, mechanisms underlying PEA rearrest are poorly understood. Previously, myocardial contractile function during ischemia-reperfusion has been tied to alterations in extracellular sodium (Na+) and calcium (Ca2+) concentrations. Objective: To determine physiological predictors and explore potential mechanisms underlying susceptibility to PEA rearrest. Methods: Acute myocardial infarction (AMI) induced by left anterior descending artery (LAD) occlusion was followed by 8 min of VF, then pigs were resuscitated (defibrillation, CPR, epinephrine) to ROSC and the LAD was reperfused. Pigs were instrumented to measure metabolic variables from arterial and coronary sinus venous blood gases, electrolytes, and hemodynamics. Subjects that had PEA rearrest (n=7) were compared to those that did not rearrest (n=4). Results: Hemodynamic and primary arrest characteristics were similar between PEA and no rearrest groups, including ischemia duration, time to ROSC, CPR events, and epinephrine administration. At ROSC, hemodynamic and metabolic variables including pH, myocardial lactate consumption, myocardial arterial/venous oxygen difference were also similar between groups. Importantly, post-ROSC myocardial lactate consumption was significantly increased in the PEA group (3.9 vs. 0.5 mmol, p&lt;0.03) as was coronary sinus Na+ (147 vs. 135 mEq/L, p&lt;.03); however, coronary sinus Ca2+ was significantly reduced (1.9 vs. 2.3 mEq/L, p&lt;.01 ). Taken together, these data suggest that metabolic substrate depletion may promote local electrolyte shifts contributing to mechanical dysfunction underlying PEA. Conclusion: PEA rearrest was associated with increased myocardial lactate consumption and derangements in cardiac Na+ and Ca2+ in a translational model with well controlled arrest characteristics. Improved understanding of mechanisms underlying post-ROSC electrolyte shifts may identify novel mechanisms and therapeutic approaches to prevent and treat PEA.

Impact of Time Factor on Wall Motion Abnormalities in Patients with STEMI and Underwent Primary PCI

Background: Left ventricular (LV) dysfunction is the single most accurate predictor of death and one of the most common and lethal consequences after ST segment elevation myocardial infarction (STEMI) that has been substantially decreased by primary percutaneous coronary intervention (PCI). This research investigated the impact of duration of ischemia on the severity and improvement of wall motion abnormalities after revascularization and 40-day follow-up.&#x0D; Methods: This study was performed on 60 STEMI patients, treated with 1ry PCI and distributed in two groups; group1: 37 patients presented early before 12h and group II: 23 patients presented late after 12h. Echocardiogram (ECHO) was done for ejection fraction (EF) and resting segmental wall motion abnormalities (RSWMA) detection after revascularization within 24 h of hospitalization and follow up after 40 days.&#x0D; Results: MI complication showed insignificant difference between both groups. Wall motion score index (WMSI) values in group I were significantly decreased relative to group II during the follow-up period (p=0.001). Major improvement in LV ejection fraction from hospital admission to follow-up (p=0.001) in group I from the beginning of chest pain compared to group II. Correlation between time to wire crossing and WMSI showed significant positive correlation after 40 days in group I (p=0.016) with significant negative correlation with EF after 40 days in group I (p=0.018).&#x0D; Conclusions: Ischemic patients with ≤ 12 hours symptoms showed a significant degree of recovery from RWMA on follow up after 40 days.

High-impact opportunities to address ischemia: a focus on heart and circulatory research.

Myocardial ischemic injury and its resolution are the key determinants of morbidity or mortality in heart failure. The cause and duration of ischemia in patients vary. Numerous experimental models and methods have been developed to define genetic, metabolic, molecular, cellular, and pathophysiological mechanisms, in addition to defining structural and functional deterioration of cardiovascular performance. The rapid rise of big data, such as single-cell analysis techniques with bioinformatics, machine learning, and neural networking, brings a new level of sophistication to our understanding of myocardial ischemia. This mini-review explores the multifaceted nature of ischemic injury in the myocardium. We highlight recent state-of-the-art findings and strategies to show new directions of high-impact approach to understanding myocardial tissue remodeling. This next age of heart and circulatory physiology research will be more comprehensive and collaborative to uncover the origin, progression, and manifestation of heart failure while strengthening novel treatment strategies.

Short-term outcomes of da Vinci Xi versus Si robotic systems for minor hepatectomies.

In the recent years, robotic technology has been drastically improved and the last generation of robotic platforms is hardly comparable with the earlier ones. The present study aims to investigate the short-term outcomes of minor hepatectomies performed with da Vinci Xi surgical system vs. Si surgical systems. Consecutive patients operated on between 2013 and 2020 in two referral centers were selected if underwent elective robotic minor hepatectomy (<3 consecutive segments) for primarily resectable benign or malignant lesions. Operative, postoperative, and cost outcomes were compared between the two groups by univariate and multivariate analyses. Eighty-nine patients were selected (64 in the Si system vs. 25 in the Xi system group). Wedge resection was the most commonly performed procedure (49.4%). The Si system group showed a significantly greater total incisional length (+8.99 mm; p<0.0001) related to the use of a higher number of robotic/laparoscopic ports. Pedicle clamping was more frequent in patients operated on by the Xi system (80% vs. 21.9%; p<0.0001) but without group differences in ischemia duration when clamping. A significantly shorter time to flatus (-0.75 days; p=0.015) was observed for patients operated on by the Xi system, whereas no group differences were found for operative time, conversion rate, estimated blood loss, postoperative complications, mortality, use of analgesics, and costs. The da Vinci Xi system represents a technological advancement with a potential clinical relevance, although further studies are needed to clearly detect the clinical impact of the use of this robotic platform in liver surgery.

P-139 THE EFFECTS OF THE INCISION TYPE ON INCISIONAL HERNIA RESULTS OF LIVING DONOR LIVER TRANSPLANT; SINGLE CENTER EXPERIENCE

Abstract Aim We aimed to assess the effects of the chosen incision type on postoperative hernia rates of liver transplantation in this paper. Material-Methods During the period between the 5th September 2018 and 31st March 2022, total 210 liver transplantations were performed in the Liver Transplantation Center of Koç University Hospital. 96 pediatric and 10 deceased donor transplantations were excluded. Living donor liver transplantation (LDLT) cases in only adults were included in the trial. Total 104 patients were included. Patients divided into two groups in the manner of chosen laparotomy incision during the operation. Reverse T incisions (Group A, n=68) and Makuuchi incisions (Group B, n=36) were performed in our center during the trial period. Minimum 3 month-follow up period was performed. Results Demographic data (Table 1) was similar in both groups. Operation and warm ischemia durations were longer in Group B (Table 2). Postoperative immunosuppressive regimens were same protocols contains tacrolimus and prednisolone. Surgical site infection rates, relaparotomy rates, postoperative blood transfusion rates, biliar, vascular and pulmonary complication rates were also similar in both groups (Table 3). While 11 patients diagnosed with incisional hernia in Group A (%16,2), 2 patients diagnosed with incisional hernia in Group B (%5,6, p=0,212). Conclusion Although Makuuchi incision seems to be safer in manner of hernia rates, this couldn't be proved by statistically significance as a result of this retrospective analysis of a single center. The necessity of prospective designed trials is obvious in order to obtain more reliable results.

Renal tumor biopsy does not increase the risk of surgical complications of minimally invasive partial nephrectomy.

For patients with cT1 renal lesions, Partial Nephrectomy (PN) is the gold standard treatment. However, 20% of small renal masses are benign, situation in which the PN is an overtreatment. The percutaneous Renal Tumor Biopsy (RTB) may lower the risk of overtreatment as there is a 90% concordance rate on histotype between the RTB and the final pathology. It has been suggested that the RTB could increase the difficulty of the PN and increase the risk of surgical complications. To compare surgical outcomes and complications of PN with or without previous RTB. monocentric retrospective review of patients who underwent laparoscopic or robotic-assisted PN between January 2012 and December 2019. perioperative complications were recorded using Clavien-Dindo classification, peroperative data included operative time, clamping time and blood loss, and histological outcomes of RTB and PN. In total, 163 patients were included in our study. There were significantly less benign lesions in PN with prior RTB: 7% (4/56) vs. 20% (22/107) without prior RTB (P=0.03). There were no significant differences regarding Clavien-Dindo>2 perioperative complications with respectively 7% (4/56) vs. 10% (11/107) (P=0.57). Same goes for peroperative data such as duration of surgery (P=0.81), warm ischemia (P=0.07) and blood loss (P=0.13). RTB does not increase the risk of surgical complications of PN and may reduce the risk of small renal masses overtreatment.

Effects of contralateral nephrectomy timing and ischemic conditions on kidney fibrosis after unilateral kidney ischemia-reperfusion injury

Acute kidney injury (AKI) is an important cause of chronic kidney disease (CKD), but the underlying mechanisms are unclear. Animal models are tools for studying the AKI-CKD progression. Kidney ischemia-reperfusion injury (IRI) models, especially the unilateral IRI (uIRI) model with delayed contralateral kidney resection, are commonly used to induce fibrotic progression to CKD after AKI. However, in previous studies, we found that details of the operation had a significant impact on the long-term outcomes of the kidney in this uIRI model. In this study, we investigated the effects of resection timing of the contralateral intact kidney, core body temperatures during ischemia, and time length of kidney ischemia on kidney function, histological injury and kidney fibrosis after AKI, using a mouse uIRI model with delayed contralateral nephrectomy. The results showed that all these parameters significantly affected the AKI-CKD transition. The post-AKI fibrosis worsened and the survival rate declined with a longer interval between contralateral nephrectomy and uIRI, higher ischemic body temperature, or longer ischemic duration when the other two variables were fixed. In conclusion, in the uIRI model with delayed contralateral nephrectomy, kidney fibrosis after AKI is influenced by many factors. Strictly controlling the experimental conditions is very important for the stability and consistency of the model.

Delayed Graft Function in Kidney Transplant: Risk Factors, Consequences and Prevention Strategies.

Background. Delayed graft function is a frequent complication of kidney transplantation that requires dialysis in the first week posttransplant. Materials and Methods. We searched for the most relevant articles in the National Institutes of Health library of medicine, as well as in transplantation, pharmacologic, and nephrological journals. Results. The main factors that may influence the development of delayed graft function (DGF) are ischemia–reperfusion injury, the source and the quality of the donated kidney, and the clinical management of the recipient. The pathophysiology of ischemia–reperfusion injury is complex and involves kidney hypoxia related to the duration of warm and cold ischemia, as well as the harmful effects of blood reperfusion on tubular epithelial cells and endothelial cells. Ischemia–reperfusion injury is more frequent and severe in kidneys from deceased donors than in those from living donors. Of great importance is the quality and function of the donated kidney. Kidneys from living donors and those with normal function can provide better results. In the peri-operative management of the recipient, great attention should be paid to hemodynamic stability and blood pressure; nephrotoxic medicaments should be avoided. Over time, patients with DGF may present lower graft function and survival compared to transplant recipients without DGF. Maladaptation repair, mitochondrial dysfunction, and acute rejection may explain the worse long-term outcome in patients with DGF. Many different strategies meant to prevent DGF have been evaluated, but only prolonged perfusion of dopamine and hypothermic machine perfusion have proven to be of some benefit. Whenever possible, a preemptive transplant from living donor should be preferred.

Changes in somatosensory evoked potentials in rats following transient cerebral ischemia

Background. Cerebral ischemia induced by transient middle cerebral artery occlusion is one of the most popular ischemic stroke models used to evaluate drug candidates with neuroprotective properties. The possibilities of combining this model with neurophysiological techniques (e.g., electroencephalography, electrocorticography, evoked potential registration, etc.) to assess the effectiveness of novel pharmacotherapeutic strategies appear to be of great interest to current biomedical research.The aim. Identifying specific changes in somatosensory evoked potentials occurring after cerebral ischemia induced by middle cerebral artery occlusion in rats.Materials and methods. A total number of 18 white outbred male rats were randomized into 3 groups by 6 animals in each: 1) control (presumably healthy animals); 2) ischemia-30 (30-minute middle cerebral artery occlusion); 3) ischemia-45 (45-minute occlusion). At post-surgery day 7, cortical responses to sequential electrical stimulation of left and right n. ischiadicus were registered. N1, P2, N2, P3, and N3 peak latencies and amplitudes, peak-to-peak interval durations and amplitudes were calculated. Spearman’s rank correlation coefficients were used to assess the relationship between ischemia duration and evoked potential parameters, and the Chaddock scale was used to qualitatively evaluate the strength of correlations.Results. The rats subjected to cerebral ischemia demonstrated a decrease in some of the peak amplitudes of the ipsi- and contralateral somatosensory potentials evoked by n. ischiadicus stimulation. In the injured hemisphere, decreased P2 and N3 peak and P3–N3 interval amplitudes were registered ipsilaterally, and decreased P3 peak amplitudes and N2–P3 interval durations were observed contralaterally.Conclusions. The obtained data suggest that somatosensory evoked potential registration and analysis can be used to evaluate the functional state of central nerve tracts in rats subjected to cerebral ischemia.

A comprehensive and longitudinal cardiac magnetic resonance imaging study of the impact of coronary ischemia duration on myocardial damage in a highly translatable animal model.

We performed a comprehensive assessment of the effect of myocardial ischemia duration on cardiac structural and functional parameters by serial cardiac magnetic resonance (CMR) and characterized the evolving scar. CMR follow-up on the cardiac impact of time of ischemia in a closed-chest animal model of myocardial infarction with human resemblance is missing. Pigs underwent MI induction by occlusion of the left anterior descending (LAD) coronary artery for 30, 60, 90 or 120 min and then revascularized. Serial CMR was performed on day 3 and day 42 post-MI. CMR measurements were also run in a sham-operated group. Cellular and molecular changes were investigated. On day 3, cardiac damage and function were similar in sham and pigs subjected to 30 min of ischemia. Cardiac damage (oedema and necrosis) significantly increased from 60 min onwards. Microvascular obstruction was extensively seen in animals with ≥90 min of ischemia and correlated with cardiac damage. A drop in global systolic function and wall motion of the jeopardized segments was seen in pigs subjected to ≥60 min of ischemia. On day 42, scar size and cardiac dysfunction followed the same pattern in the animals subjected to ≥60 min of ischemia. Adverse left ventricular remodelling (worsening of both LV volumes) was only present in animals subjected to 120 min of ischemia. Cardiac fibrosis, myocyte hypertrophy and vessel rarefaction were similar in the infarcted myocardium of pigs subjected to ≥60 min of ischemia. No changes were observed in the remote myocardium. Sixty-minute LAD coronary occlusion already induces cardiac structural and functional alterations with longer ischemic time (120 min) causing adverse LV remodelling.

Post-Operative Kidney Function Using Deep Hypothermic Circulatory Arrest (DHCA) in Aortic Arch Operation.

BackgroundAlthough deep hypothermic circulatory arrest (DHCA) is a useful option to protect the central nervous system during aortic arch operations, the influence of simultaneous renal ischemia remains controversial.Patients and MethodsThis is a retrospective observational study. Sixty-three patients who underwent thoracic aortic surgery with DHCA and 24 patients who underwent cardiac surgery without DHCA were included in this study. The mean age, preoperative serum creatinine (Cr) level, preoperative estimated glomerular filtration rate (eGFR), peak serum Cr level up to 48 hrs post-operative, elevation rate of Cr compared to the preoperative serum Cr, urine volume rate up to 48 hrs post-operative and AKI staging using the KDIGO criteria were estimated for each patient. Clinical parameters for 3 months after the operation and the 3-month post-operative mortality rate were assessed. Mean values indicating kidney function or distribution of the AKI stages were compared between patients with and without DHCA. Patients with DHCA were further divided according to the duration of ischemia to compare the values for the kidney function of each group, distribution of AKI stages and mortality.ResultsThe parameters indicating AKI of the patients with DHCA were significantly more severe than those without DHCA. Patients who had undergone an ischemic state for more than 40 min revealed significantly higher peak serum Cr, elevation rate of serum Cr, less urine volume up to 48 hrs post-operative compared with those without DHCA. Distribution of the AKI stages was related to the duration of ischemia. The 3-month post-operative mortality of the patients with DHCA was significantly higher than those without DHCA.LimitationsThis study had limitations such as its retrospective design and small number patients, and the data will be required confirmation with other prospective studies.ConclusionDHCA is closely related to AKI up to 48 hrs post-operative and death during the 3 months following surgery.

Time and Brain Region-Dependent Excitatory Neurochemical Alterations in Bilateral Common Carotid Artery Occlusion Global Ischemia Model.

Strict metabolic regulation in discrete brain regions leads to neurochemical changes in cerebral ischemia. Accumulation of extracellular glutamate is one of the early neurochemical changes that take place during cerebral ischemia. Understanding the sequential neurochemical processes involved in cerebral ischemia-mediated excitotoxicity before the clinical intervention of revascularization and reperfusion may greatly influence future therapeutic strategies for clinical stroke recovery. This study investigated the influence of time and brain regions on excitatory neurochemical indices in the bilateral common carotid artery occlusion (BCCAO) model of global ischemia. Male Wistar rats were subjected to BCCAO for 15 and 60min to evaluate the effect of ischemia duration on excitatory neurochemical indices (dopamine level, glutamine synthetase, glutaminase, glutamate dehydrogenase, aspartate aminotransferase, monoamine oxidase, acetylcholinesterase, and Na+ K+ ATPase activities) in the discrete brain regions (cortex, striatum, cerebellum, and hippocampus). BCCAO without reperfusion caused marked time and brain region-dependent alterations in glutamatergic, glutaminergic, dopaminergic, monoaminergic, cholinergic, and electrogenic homeostasis. Prolonged BCCAO decreased cortical, striatal, and cerebellar glutamatergic, glutaminergic, dopaminergic, cholinergic, and electrogenic activities; increased hippocampal glutamatergic, glutaminergic, dopaminergic, and cholinergic activities, increased cortical and striatal monoaminergic activity; decreased cerebellar and hippocampal monoaminergic activity; and decreased hippocampal electrogenic activity. This suggests that excitatory neurotransmitters play a major role in the tissue-specific metabolic plasticity and reprogramming that takes place between the onset of cardiac arrest-mediated global ischemia and clinical intervention of recanalization. These tissue-specific neurochemical indices may serve as diagnostic and therapeutic strategies for mitigating the progression of ischemic damage before revascularization.

An ECG generative model of myocardial infarction

Background and Objective Computer-aided diagnosis (CAD) of Myocardial Infarction (MI) using machine learning depends on a large amount of clinical Electrocardiogram (ECG) data. Existing infarct ECG databases face the problem of class imbalance. Data augmentation using generative simulation models is a new approach to effectively address this problem.Methods A multiscale ECG generative model was established for ECG data augmentation. In the cellular layer, an ischemic Action Potential (AP) model was established to generate APs in cardiomyocytes with different transmural regions of infraction or different ischemic durations. In the tissue layer, a probability-driven cellular automata excitation propagation model was established to simulate the propagation speed and direction of excitation. An infarct tissue model and a coronary artery model were established to describe the spatiotemporal diversity of MI. A ventricle model, a human torso model, and a computational model of surface ECG based on field source theory were established in the heart-torso layer.Results The model generated pathological 12-lead ECGs of MI with different topography and different extent. When simulating different ventricular wall infarction, the lesions appear in the same leads as the clinical 12-lead ECG. The ST-segment decreases and the T-wave amplitude decreases, similar to the clinical ECG features when simulating subendocardial ischemia. The average fidelity of the 12-lead ECG the model generated is 95.6%, according to the designed DTW-GRA distance algorithm.Conclusions The generative model considers the electrophysiological properties of the natural heart, the pathology of myocardial infarction, and the diversity of clinical ECGs. The model can provide many reliable samples for machine learning of MI.