Rising Mortality in Coronavirus-19 Patients Supported With Extracorporeal Membrane Oxygenation.

We aimed to describe practice patterns and outcomes in patients with extracorporeal membrane oxygenation (ECMO) support throughout the coronavirus 2019 (COVID-19) pandemic, with the hypothesis that mortality would improve as we accumulated knowledge and experience. We included 48 patients supported on veno-venous ECMO (VV-ECMO) at a single institution between April 2020 and December 2021. Patients were categorized into three waves based on cannulation date, corresponding to the wild-type (wave 1), alpha (wave 2), and delta (wave 3) variants. One hundred percent of patients in waves 2 and 3 received glucocorticoids, compared with 29% in wave 1 ( p < 0.01), and the majority received remdesivir (84% and 92% in waves 2 and 3, vs . 35% in wave 1; p < 0.01). Duration of pre-ECMO noninvasive ventilation was longer in waves 2 and 3 (mean 8.8 days and 3.9 days, vs . 0.7 days in wave 1; p < 0.01), as was time to cannulation (mean 17.2 and 14.6 days vs . 8.8 days in wave 1; p < 0.01) and ECMO duration (mean 55.7 days and 43.0 days vs . 28.4 days in wave 1; p = 0.02). Mortality in wave 1 was 35%, compared with 63% and 75% in waves 2 and 3 ( p = 0.05). These results suggest an increased prevalence of medically refractory disease and rising mortality in later variants of COVID-19.

Multiple Arterial Graft Use in Coronary Artery Bypass Surgery: Surgeon Perspective vs Practice.

BACKGROUND: Despite supportive evidence and guidelines, the use of multiple arterial grafts (MAGs) in coronary artery bypass grafting remains low. We sought to determine surgeon perception of personal MAG use and compare this with actual MAG use. METHODS: We conducted a statewide surgeon survey of MAG use, presence of a hospital MAG protocol, and barriers for MAG use, with a response rate of 78% (n = 25). Surgeon survey responses were compared with actual Society of Thoracic Surgeons patient data from January 1, 2017, to December 31, 2020 using χ2 or Fisher's exact tests. RESULTS: Of 5299 patients who had first-time, nonemergent, isolated coronary artery bypass grafting (≥2 grafts) by responding surgeons, 16% received MAG (n = 825). MAG use in patients whose surgeons self-designated as "routine" MAG users was 21% vs 7% for "nonroutine" users. Surgeons with a hospital protocol for MAG use utilized MAG more often (18% vs 14%, P = .001). Surgeons who were unconvinced by the data on the benefits of MAGs used MAGs in 11% vs 22% in surgeons who were convinced. MAG use increased over time, particularly from before to after the survey (13.1% vs 30.5%, P < .001). CONCLUSIONS: Although MAG use increased over time, barriers to routine use remain. In surgeons who reported routine use, only 21% of their patients received MAGs. Hospital protocols, education, and increased awareness may reduce barriers to use and encourage evidence-based clinical practice.

Ketamine Mitigates Neurobehavioral Deficits in a Canine Model of Hypothermic Circulatory Arrest.

Hypothermic circulatory arrest is a protective technique used when complete cessation of circulation is required during cardiac surgery. Prior efforts to decrease neurologic injury with the NMDA receptor antagonist MK801 were limited by unacceptable side effects. We hypothesized that ketamine would provide neuroprotection without dose-limiting side effects. Canines were peripherally cannulated for cardiopulmonary bypass, cooled to 18°C, and underwent 90 minutes of circulatory arrest. Ketamine-treated canines (n = 5; total dose 2.85 mg/kg) were compared to untreated controls (n = 10). A validated neurobehavioral deficit score was obtained at 24, 48, and 72 hours (0 = no deficits/normal exam; higher score represents increasing deficits). Biomarkers of neuronal injury in the cerebrospinal fluid were examined at baseline and at 8, 24, 48, and 72 hours. Brain histopathologic injury was scored at 72 hours (higher score indicates more necrosis and apoptosis). Ketamine-treated canines had significantly improved, lower neurobehavioral deficit scores compared to controls (overall P = 0.003; 24 hours: median 72 vs 112, P = 0.030; 48 hours: 47 vs 90, P = 0.021; 72 hours: 30 vs 89, P = 0.069). Although the histopathologic injury scores of ketamine-treated canines (median 12) were lower than controls (16), there was no statistical difference (P = 0.10). Levels of phosphorylated neurofilament-H and neuron specific enolase, markers of neuronal injury, were significantly lower in ketamine-treated animals (P = 0.010 and = 0.039, respectively). Ketamine significantly reduced neurologic deficits and biomarkers of injury in canines after hypothermic circulatory arrest. Ketamine represents a safe and approved medication that may be useful as a pharmacologic neuroprotectant during cardiac surgery with circulatory arrest.

ATP-Sensitive Potassium Channel Opener Diazoxide Reduces Myocardial Stunning in a Porcine Regional With Subsequent Global Ischemia Model.

Background ATP-sensitive potassium channels are inhibited by ATP and open during metabolic stress, providing endogenous myocardial protection. Pharmacologic opening of ATP potassium channels with diazoxide preserves myocardial function following prolonged global ischemia, making it an ideal candidate for use during cardiac surgery. We hypothesized that diazoxide would reduce myocardial stunning after regional ischemia with subsequent prolonged global ischemia, similar to the clinical situation of myocardial ischemia at the time of revascularization. Methods and Results Swine underwent left anterior descending occlusion (30 minutes), followed by 120 minutes global ischemia protected with hyperkalemic cardioplegia±diazoxide (N=6 each), every 20 minutes cardioplegia, then 60 minutes reperfusion. Cardiac output, time to wean from cardiopulmonary bypass, left ventricular (LV) function, caspase-3, and infarct size were compared. Six animals in the diazoxide group separated from bypass by 30 minutes, whereas only 4 animals in the cardioplegia group separated. Diazoxide was associated with shorter but not significant time to wean from bypass (17.5 versus 27.0 minutes; P=0.13), higher, but not significant, cardiac output during reperfusion (2.9 versus 1.5 L/min at 30 minutes; P=0.05), and significantly higher left ventricular ejection fraction at 30 minutes (42.5 versus 15.8%; P<0.01). Linear mixed regression modeling demonstrated greater left ventricular developed pressure (P<0.01) and maximum change in ventricular pressure during isovolumetric contraction (P<0.01) in the diazoxide group at 30 minutes of reperfusion. Conclusions Diazoxide reduces myocardial stunning and facilitates separation from cardiopulmonary bypass in a model that mimics the clinical setting of ongoing myocardial ischemia before revascularization. Diazoxide has the potential to reduce myocardial stunning in the clinical setting.

Extracorporeal Membrane Oxygenation Complications in Heparin- and Bivalirudin-Treated Patients.

Extracorporeal membrane oxygenation is a potentially life-saving intervention in refractory cardiopulmonary failure, but it requires anticoagulation to prevent circuit thromboses, which exposes the patient to hemorrhagic complications. Heparin has traditionally been the anticoagulant of choice, but the direct thrombin inhibitor bivalirudin is routinely used in cases of heparin-induced thrombocytopenia and has been suggested as a superior choice. We sought to examine the timing of hemorrhagic and thrombotic complications after extracorporeal membrane oxygenation cannulation and to compare the rates of such complications between patients anticoagulated with heparin versus bivalirudin. DESIGN: Retrospective cohort study. SETTING: Johns Hopkins Hospital patients between January 2016 and July 2019. PATIENTS: Adult (> 18 yr) extracorporeal membrane oxygenation patients. INTERVENTIONS: Patients were anticoagulated either with heparin or bivalirudin. MEASUREMENTS AND MAIN RESULTS: We compared rates of hemorrhagic and thrombotic complications by time on heparin versus bivalirudin and characterized the average time to each complication. Of 144 extracorporeal membrane oxygenation patients (mean age 55.3 yr; 58% male), 41% were on central venoarterial extracorporeal membrane oxygenation, 40% on peripheral venoarterial extracorporeal membrane oxygenation, and 19% on venovenous extracorporeal membrane oxygenation. Thirteen patients (9%) received bivalirudin during their extracorporeal membrane oxygenation run, due to concern for (n = 8) or diagnosis of (n = 4) heparin-induced thrombocytopenia or for heparin resistance (n = 1). The rate of hemorrhagic or thrombotic complications did not differ between heparin (0.13/d) and bivalirudin (0.06/d; p = 0.633), but patients on bivalirudin received significantly fewer blood transfusions (1.0 U of RBCs/d vs 2.9/d on heparin; p < 0.001). CONCLUSIONS: Our results confirm the safety and efficacy of bivalirudin as an alternative anticoagulant in extracorporeal membrane oxygenation and suggest a potential benefit in less blood product transfusion, although prospective studies are needed to evaluate the true effect of bivalirudin versus the disease processes that prompted its use in our study population.

Ochronotic heart disease leading to severe aortic valve and coronary artery stenosis.

Cardiac ochronosis is a rare disease, estimated to affect 1 in 250,000 persons. While there is extensive evidence of the musculoskeletal alterations of the disease, cardiac involvement has not been widely studied and most information we currently have derives from case reports and case series. We report the case of a 64-year old patient with a known history of alkaptonuria who presented with dyspnea and weight loss. On evaluation, he was found to have severe aortic stenosis, coronary artery disease, and interventricular septal hypertrophy. Surgery revealed extensive ochronotic pigment deposition affecting the cardiac septum, both internal thoracic arteries, the native coronary arteries, and the aortic valve. Ochronotic heart disease is an often disregarded presentation of alkaptonuria. More information is needed on the course of the disease, as well as long-term outcomes after valve replacement surgery and/or coronary artery bypass grafting in patients with alkaptonuria.

Measures to Increase Use of Multiple Arterial Grafts for Isolated Coronary Artery Bypass Grafting.

BACKGROUND: Use of multiple arterial grafts (MAGs) provides superior patency and long-term survival benefit compared with venous grafts during coronary artery bypass grafting (CABG). However, MAGs are used infrequently for CABG. We hypothesized that specific measures introduced at our institution would lead to an increase in the use of MAGs. STUDY DESIGN: Use of MAGs before and after introduction of bundled measures was compared. Measures included increased education in arterial graft harvesting, inclusion as a quality metric, and hiring of surgeon champions. Patients younger than 70 years who underwent first time, isolated CABG using at least 1 arterial graft were included. Number and type of grafts used were compared between time periods using chi-square test. Secondary outcomes included postoperative complications. Complications were compared between time periods, as well as between MAG and non-MAG recipients before and after propensity score matching using Fisher exact test and univariate logistic regression. Multivariable logistic regression was used to determine patient characteristics associated with MAG use. RESULTS: There were 2,169 patients included from 2012 to 2019. MAG use increased significantly after introduction of measures (21.1% to 41.9%; p < 0.001). Radial artery use with an internal mammary artery (0.3% to 16%; p < 0.001) and the use of triple arterial grafts increased significantly (0% to 2.4%; p < 0.001). MAG use in the entire cohort was associated with decreased 30-day mortality and postoperative cardiac arrest that was not significant after propensity matching. CONCLUSIONS: A programmatic emphasis on the use of MAGs for CABG is an effective method to increase its use.

Aortitis masquerading as intramural hematoma: When to observe, when to operate? A case report.

Radiologic evidence of aortic disease is not always consistent with the diagnosis. With a lack of accompanying symptoms or with an atypical presentation, diagnosis, and management of aortic pathology rely greatly on imaging techniques. We report the case of a 58-year-old female who presented with incidental radiographic findings consistent with a type A aortic intramural hematoma and a vague left-sided chest discomfort. After follow-up, imaging was consistent with disease progression and hematoma expansion; the affected segment was resected and pathology reported lymphoplasmacytic aortitis as the underlying etiology of the imaging findings rather than an intramural hematoma. The patient lacked symptoms or serology consistent with the rheumatologic disease, and the postoperative course was uneventful. The management of a suspected ascending intramural hematoma is controversial, especially when the patient presents with atypical signs and symptoms. Features of disease progression may warrant urgent surgical intervention.