Heart Rate Variability: A possible machine learning biomarker for mechanical circulatory device complications and heart recovery

Cardiovascular disease continues to be the number one cause of death in the United States, with heart failure patients expected to increase to \u3e8 million by 2030. Mechanical circulatory support (MCS) devices are now better able to manage acute and chronic heart failure refractory to medical therapy, both as bridge to transplant or as bridge to destination. Despite significant advances in MCS device design and surgical implantation technique, it remains difficult to predict response to device therapy. Heart rate variability (HRV), measuring the variation in time interval between adjacent heartbeats, is an objective device diagnostic regularly recorded by various MCS devices that has been shown to have significant prognostic value for both sudden cardiac death as well as all-cause mortality in congestive heart failure (CHF) patients. Limited studies have examined HRV indices as promising risk factors and predictors of complication and recovery from left ventricular assist device therapy in end-stage CHF patients. If paired with new advances in machine learning utilization in medicine, HRV represents a potential dynamic biomarker for monitoring and predicting patient status as more patients enter the mechanotrope era of MCS devices for destination therapy

Human immunodeficiency virus and anaesthesia

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Nucleotide metabolic mismatches in mammalian hearts: implications for transplantation

INTRODUCTION: Human donor organ shortages have led surgeons and scientists to explore the use of animals as alternative organ sources. Acute thrombovascular rejection (AVR) is the main hurdle in xenotransplantation. Disparities in nucleotide metabolism in the vessels of different species may contribute significantly to the microvascular component of AVR. METHODS: We evaluated the extent of nucleotide metabolism mismatch in selected organs and endothelial cells of different mammals with particular focus on the changes in activity of ecto-5’-nucleotidase (E5’N) elicited by exposure of porcine hearts or endothelial cells to human blood (ex vivo) or human plasma (in vitro). RESULTS: E5’N activity in the rat heart was significantly higher than in other species. We noted a significant difference (p<0.001) in E5’N activity between human and pig endothelial cell lines. Initial pig aortic endothelial E5’N activity decreased in vitro after a three-hour exposure to human and porcine plasma while remaining constant in controls. Ex vivo perfusion with fresh human blood for four hours resulted in a significant decrease of E5’N activity in both wild type and transgenic pig hearts overexpressing human decay accelerating factor (p<0.001). CONCLUSIONS: This study provides evidence that mismatches in basal mammalian metabolic pathways and humoral immunity interact in a xenogeneic environment. Understanding the role of nucleotide metabolism and signalling in xenotransplantation may identify new targets for genetic modifications and may lead to the development of new therapies extending graft survival

Complex I dysfunction underlies the glycolytic switch in pulmonary hypertensive smooth muscle cells.

ATP is essential for cellular function and is usually produced through oxidative phosphorylation. However, mitochondrial dysfunction is now being recognized as an important contributing factor in the development cardiovascular diseases, such as pulmonary hypertension (PH). In PH there is a metabolic change from oxidative phosphorylation to mainly glycolysis for energy production. However, the mechanisms underlying this glycolytic switch are only poorly understood. In particular the role of the respiratory Complexes in the mitochondrial dysfunction associated with PH is unresolved and was the focus of our investigations. We report that smooth muscle cells isolated from the pulmonary vessels of rats with PH (PH-PASMC), induced by a single injection of monocrotaline, have attenuated mitochondrial function and enhanced glycolysis. Further, utilizing a novel live cell assay, we were able to demonstrate that the mitochondrial dysfunction in PH-PASMC correlates with deficiencies in the activities of Complexes I-III. Further, we observed that there was an increase in mitochondrial reactive oxygen species generation and mitochondrial membrane potential in the PASMC isolated from rats with PH. We further found that the defect in Complex I activity was due to a loss of Complex I assembly, although the assembly of Complexes II and III were both maintained. Thus, we conclude that loss of Complex I assembly may be involved in the switch of energy metabolism in smooth muscle cells to glycolysis and that maintaining Complex I activity may be a potential therapeutic target for the treatment of PH

Traumatic pericardial rupture with skeletonized phrenic nerve

<p>Abstract</p> <p>Background</p> <p>Traumatic pericardial rupture is a rare presentation. Pericardial rupture itself is asymptomatic unless complicated by either hemorrhage or herniation of the heart through the defect. Following diagnosis surgical repair of the pericardium is indicated because cardiac herniation may result in vascular collapse and sudden death.</p> <p>Objectives</p> <p>Here we present a case of traumatic, non-herniated pericardial rupture with complete skeletonization of the phrenic nerve.</p> <p>Case report</p> <p>An 18-year-old healthy male suffered multi-trauma after falling 50 feet onto concrete. The patient could not be stabilized despite exploratory laparotomy with splenectomy, IR embolization and packing for a liver laceration. Right posterolateral thoracotomy revealed a ruptured pericardium with a completely skeletonized phrenic nerve. The pericardium was repaired with a Goretex(R) patch.</p> <p>Conclusion</p> <p>A high level of suspicion for pericardial rupture is necessary in all patients with high-velocity thoracic injuries.</p

Effect of preoperative statins in patients without coronary artery disease who undergo cardiac surgery

Objective3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) have been shown to have pleiotropic effects in addition to their lipid-lowering properties. Some studies have shown the beneficial effect of preoperative statins on operative outcomes in coronary artery bypass grafting. However, the effect of preoperative statins in patients without coronary artery disease who undergo cardiac surgery remains poorly defined.MethodsWe performed a retrospective review of 1389 consecutive patients undergoing cardiac valve surgery between January of 2002 and December of 2005. Patients undergoing concomitant coronary artery bypass surgery and those with a history of myocardial infarction and coronary interventions were excluded. Of this cohort, 363 patients were receiving a statin preoperatively and 1026 patients were not. Propensity scores were constructed with patients' demographics, clinical data, and the year of procedure. Generalized estimating equations, including the propensity score as a covariate, were used to investigate whether preoperative statin use is associated with improved operative outcomes.ResultsThe crude operative mortality rate was 0.8% and 2.3%, the incidence of stroke was 1.7% and 2.9%, and the incidence of perioperative myocardial infarction was 2.2% and 2.4% in the statin and non-statin groups, respectively. Generalized estimating equations showed that preoperative statin use is associated with lower mortality (odds ratio: 0.25, 95% confidential interval: 0.12–0.54). Preoperative statin use was not significantly associated with an incidence of stroke (odds ratio: 0.48, 95% confidential interval: 0.19–1.22) or perioperative myocardial infarction (odds ratio: 0.91, 95% confidential interval: 0.43–1.91) in this cohort.ConclusionPreoperative use of statins may improve operative outcomes in patients without coronary artery disease who undergo cardiac surgery

The importance of prevention of calciphylaxis in patients who are at risk and the potential fallibility of calcimimetics in the treatment of calciphylaxis for patients with secondary hyperparathyroidism

A 43-year-old African American with end-stage renal disease (ESRD) associated with membranous nephropathy and a previously failed renal transplant had received cinacalcet to treat his secondary hyperparathyroidism. Serum calcium and phosphorus levels remained within normal limits, and serum parathyroid levels had dropped significantly following treatment initiation. However, within 7 months, the patient experienced extensive necrotic bilateral medial thigh ulcers. These were biopsied and found to be a result of calciphylaxis. The patient ultimately required an urgent subtotal parathyroidectomy and recovered well with completely healed ulcers

Recurrent post-partum coronary artery dissection

Coronary artery dissection is a rare but well-described cause for myocardial infarction during the post-partum period. Dissection of multiple coronary arteries is even less frequent. Here we present a case of recurrent post-partum coronary artery dissections. This unusual presentation poses unique problems for management. A 35 year-old female, gravida 3 para 2, presented with myocardial infarction 9 weeks and 3 days post-partum. Cardiac catheterization demonstrated left anterior descending (LAD) dissection but an otherwise normal coronary anatomy. The lesion was treated with four everolimus eluting stents. Initially the patient made an unremarkable recovery until ventricular fibrillation arrest occurred on the following day. Unsynchronized cardioversion restored a normal sinus rhythm and repeat catheterization revealed new right coronary artery (RCA) dissection. A wire was passed distally, but it was unclear whether this was through the true or false lumen and no stents could be placed. However, improvement of distal RCA perfusion was noted on angiogram. Despite failure of interventional therapy the patient was therefore treated conservatively. Early operation after myocardial infarction has a significantly elevated risk of mortality and the initial dissection had occurred within 24 hours. This strategy proved successful as follow-up transthoracic echocardiography after four months demonstrated a preserved left ventricular ejection fraction of 55-60% without regional wall motion abnormalities. The patient remained asymptomatic from a cardiac point of view