Search PubMed⌕ Search

Biomedical subjects

Stanton K Shernan

Publications and source records attributed to Stanton K Shernan.

At least 37 records · Page 2Linked to original sources

Terminal complement blockade with pexelizumab during coronary artery bypass graft surgery requiring cardiopulmonary bypass: a randomized trial.

CONTEXT: Inflammation and ischemia-reperfusion injury during coronary artery bypass graft (CABG) surgery requiring cardiopulmonary bypass are associated with postoperative myocardial infarction (MI) and mortality. OBJECTIVE: To determine the efficacy and safety of pexelizumab, a C5 complement inhibitor, in reducing perioperative MI and mortality in CABG surgery. DESIGN, SETTING, AND PARTICIPANTS: A randomized, double-blind, placebo-controlled trial, including 3099 patients (> or = 18 years) undergoing CABG surgery with or without valve surgery at 205 hospitals in North America and Western Europe from January 2002 to February 2003. INTERVENTIONS: Patients were randomly assigned to receive intravenous pexelizumab (2.0 mg/kg bolus plus 0.05 mg/kg per hour for 24 hours; n = 1553) or placebo (n = 1546) 10 minutes before undergoing the procedure. MAIN OUTCOME MEASURES: The primary composite end point was the incidence of death or MI within 30 days of randomization in those undergoing CABG surgery only (n = 2746). Secondary analyses included the intent-to-treat analyses of death or MI composite at days 4 and 30 in all 3099 study patients. RESULTS: After 30 days, 134 (9.8%) of 1373 of patients receiving pexelizumab vs 161 (11.8%) of 1359 of patients receiving placebo (relative risk, 0.82; 95% confidence interval, 0.66-1.02; P =.07) died or experienced MI in the CABG surgery only population. In the intent-to-treat analyses, 178 (11.5%) of 1547 patients receiving pexelizumab vs 215 (14.0%) of 1535 receiving placebo died or experienced MI (relative risk, 0.82; 95% confidence interval, 0.68-0.99; P =.03). The trial was not powered to detect a reduction in mortality alone. CONCLUSIONS: Compared with placebo, pexelizumab was not associated with a significant reduction in the risk of the composite end point of death or MI in 2746 patients who had undergone CABG surgery only but was associated with a statistically significant risk reduction 30 days after the procedure among all 3099 patients undergoing CABG with or without valve surgery.

Aged↗

Impact of pexelizumab, an anti-C5 complement antibody, on total mortality and adverse cardiovascular outcomes in cardiac surgical patients undergoing cardiopulmonary bypass.

BACKGROUND: During cardiac surgery requiring cardiopulmonary bypass, pro-inflammatory complement pathways are activated by exposure of blood to bio-incompatible surfaces of the extracorporeal circuit and reperfusion of ischemic organs. Complement activation promotes the generation of additional inflammatory mediators thereby exacerbating tissue injury. We examined the safety and efficacy of a C5 complement inhibitor for attenuating inflammation-mediated cardiovascular dysfunction in cardiac surgical patients undergoing cardiopulmonary bypass. METHODS: Pexelizumab (Alexion Pharmaceuticals, Inc, Cheshire, CT), a recombinant, single-chain, anti-C5 monoclonal antibody, was evaluated in a randomized, double-blinded, placebo-controlled, multicenter trial that involved 914 patients undergoing coronary artery bypass grafting with or without valve surgery requiring cardiopulmonary bypass. RESULTS: Pexelizumab was administered intravenously as a bolus (2.0 mg/kg) or bolus plus infusion (2.0 mg/kg plus 0.05 mg/kg/h for 24 hours), and inhibited complement activation. There were no statistically significant differences between placebo-treated and pexelizumab-treated patients in the primary endpoint (composite of death, or new Q-wave, or non-Q-wave [myocardial-specific isoform of creatine kinase > 60 ng/mL] myocardial infarction, or left ventricular dysfunction, or new central nervous system deficit). However, post hoc analysis revealed a reduction in the composite of death or myocardial infarction (myocardial-specific isoform of creatine kinase >/= 100 ng/mL) for the isolated coronary artery bypass grafting, bolus plus infusion subgroup on POD 4 (p = 0.007) and on POD 30 (p = 0.004). CONCLUSIONS: Pexelizumab had no statistically significant effect on the primary endpoint. However, the reduction in death or myocardial infarction (myocardial-specific isoform of creatine kinase >/= 100 ng/mL) as revealed in the post hoc analysis in the isolated coronary artery bypass grafting bolus plus infusion subpopulation, suggests that further investigation of anti-C5 therapy for ameliorating complement-mediated inflammation and myocardial injury is warranted.

Antibodies, Monoclonal↗

Unrecognized left ventricular thrombus during reoperative coronary artery bypass grafting.

Left ventricular thrombus after myocardial infarction is relatively common but rarely threatening enough to warrant surgical removal at the time of coronary revascularization. The rare cases of ventricular thrombectomy described in the literature involve a pedunculated thrombus. We describe an urgent coronary revascularization procedure in a patient who had unrecognized left ventricular thrombus. The large clot was detected by transesophageal echocardiography after decannulation in a hemodynamically unstable patient. The thrombus was removed after placing the patient back on cardiopulmonary bypass emergently. He recovered and was discharged with no neurologic sequelae. Aggressive removal of clot using cardiopulmonary bypass is warranted even for the critically ill patient.

Aged↗

Transesophageal echocardiography for detecting extrapulmonary thrombi during pulmonary embolectomy.

BACKGROUND: Pulmonary embolectomy is an evolving surgical procedure for the treatment of severe pulmonary embolism. In addition to removing pulmonary thromboemboli, the achievement of optimal results also requires identification and extraction of intrathoracic, extrapulmonary thromboemboli from the right atrium, right ventricle, and the superior or inferior vena cava. Otherwise, these thromboemboli may become the source of recurrent pulmonary embolism. Intraoperative transesophageal echocardiography is frequently used during pulmonary embolectomy as a guide for the surgeon and a monitor of cardiac performance. However, its utility for detecting concurrent intrathoracic, extrapulmonary thromboemboli has not been thoroughly investigated. METHODS: The study population included 50 consecutive patients undergoing emergent pulmonary embolectomy. Results from preoperative diagnostic studies including transthoracic echocardiography; ventilation/perfusion scan, pulmonary angiography, and computed tomography were reviewed, along with the intraoperative echocardiographic reports for the presence of intrathoracic extrapulmonary thromboemboli. In addition, the surgical operative notes were consulted to determine the impact of intraoperative transesophageal echocardiography on surgical decision making. RESULTS: Extrapulmonary intrathoracic thromboemboli were identified preoperatively in 8 patients (16%). Intraoperatively, thromboemboli were identified in 5 additional patients by transesophageal echocardiography, adding to a total of 13 patients with extrapulmonary thrombi (26%). Intraoperative transesophageal echocardiography provided the sole source of evidence that directed surgical management in 10% (5 of 50) of all patients undergoing pulmonary emboletcomy. CONCLUSIONS: Intraoperative transesophageal echocardiography identified intrathoracic, extrapulmonary thomboemboli in 26% of patients undergoing pulmonary embolectomy, resulting in an alteration of surgical management in 10% of patients. These findings support the critical role of intraoperative echocardiography during pulmonary embolectomy.

Adult↗

Severity of intraoperative tricuspid regurgitation predicts poor late survival following cardiac transplantation.

BACKGROUND: This study evaluates the significance of tricuspid regurgitation (TR) on long-term survival as detected by intraoperative transesophageal echocardiography at the time of orthotopic heart transplantation. Although significant (2+ to 4+) TR after orthotopic heart transplantation is rare, its influence on long-term survival is unknown, warranting further investigation. METHODS: Between January 1992 and July 2001, 181 consecutive patients underwent orthotopic heart transplantation. Tricuspid regurgitation was graded by intraoperative transesophageal echocardiography after final separation from cardiopulmonary bypass in 130 of 181 patients (72%). RESULTS: Although 80% (104/130) of patients had either no (0, n = 77) or trace (1+, n = 27) TR, 9% (12/130 patients) had mild (2+), 10% (13/130 patients) had moderate (3+), and 0.8% (1/130 patients) had severe (4+) TR. The severity correlated strongly with the presence of right ventricular dysfunction (p < 0.001). In a multivariate regression model, gender mismatch (p = 0.002) and right ventricular dysfunction (p < 0.001) were independent predictors for equal to or greater than mild (2+ to 4+) TR (p = 0.015). Although the degree of recipient pulmonary vascular resistance did not influence the grade (p = 0.600), higher pulmonary vascular resistance tended to increase the severity of TR in the setting of prolonged donor ischemic times (p = 0.054). Proportional hazards regression analysis demonstrated significantly decreased survival for patients with mild or greater (2+ to 4+) TR detected by transesophageal echocardiography at the time of transplantation (p < 0.001) and RV dysfunction (p = 0.023). CONCLUSIONS: Even mild (> or = 2+) TR identified by transesophageal echocardiography at the time of orthotopic heart transplant predicts poor late survival, suggesting a possible role for concomitant tricuspid valve repair at the time of transplant. Whether or not tricuspid valve repair will improve long-term survival is unknown.

Acute Kidney Injury↗

Risk factors and outcomes for 'vasoplegia syndrome' following cardiac transplantation.

OBJECTIVE: Vasoplegia syndrome after orthotopic heart transplantation (OHT) is a rare but highly lethal syndrome of unknown etiology, characterized by severe refractory hypotension, metabolic acidosis, and decreased systemic vascular resistance (SVR). The objective of this retrospective study was to identify the risk factors contributing to the development of vasoplegia syndrome after OHT in order to provide potential algorithms for its management. METHODS: Between October 1992 and July 2001, 187 consecutive patients underwent OHT. Complete pre- and post-data were available in 147 patients (78%). Mean age was 49+/-11 years, 82% (120/147) were male, and donor ischemic time was 117+/-62 min. Twenty-eight of 147 (19%) developed vasoplegia syndrome, defined as SVR <800 dyns per cm(5) with serum bicarbonate <20 mEq/l. RESULTS: Patients who developed vasoplegia syndrome demonstrated greater hospital mortality (25 vs. 9%, P=0.031) compared to those who did not. Multivariate logistic regression identified pre-operative use of intravenous heparin (OR 2.8, CI 1-7.4, P=0.039) and body surface area >1.9 m(2) (OR 7, CI 0.98-50, P=0.052) as independent predictors for the development of post-operative vasoplegia syndrome. Pre-operative use of inotropic support conferred protection against the development of post-operative vasoplegia syndrome (OR 0.25, CI 0.08-0.79, P=0.018). Pre-operative use of ACE inhibitors was not associated with increased risk (55 vs. 59%, P=0.441). CONCLUSIONS: Vasoplegia syndrome following OHT is associated with high early mortality. The development of a risk stratification profile may help in patient selection as well as the post-operative management of vasoplegia syndrome following OHT.

Acidosis↗

Predictive genomics of adverse events after cardiac surgery.

Significant, yet highly individual, thrombotic and inflammatory responses to surgery provide an excellent opportunity for insight into the genomic impact upon a patient's postoperative course. Cardiac surgery elicits the most profound perioperative disturbance and is associated with the highest incidence of adverse outcomes of any elective surgical procedure. Thus, cardiac surgical patients are an ideal population in which to evaluate the influence of complex traits on perioperative morbidity and mortality. This review describes the application of fundamental genetics upon the occurrence of adverse outcomes after cardiac surgery and cardiac transplantation. Specific emphases include a brief primer of the principles of genetics concentrating on the effects of variation within the human genome upon clinical outcomes and the differences between so-called Mendelian traits and complex traits. Four important clinical diseases dealt with in this review as examples of the impact of genetic factors on clinical outcomes are the genetics of heparin-induced thrombocytopenia, heart transplantation rejection and vasculopathy, atrial fibrillation, and infection.

Atrial Fibrillation↗

Utility of intraoperative transesophageal echocardiography for diagnosis of pulmonary embolism.

Pulmonary embolism (PE) is associated with significant perioperative morbidity and mortality. Transesophageal echocardiography (TEE) may permit direct visualization of PE or secondary signs of pulmonary artery (PA) obstruction. However, its utility in diagnosing PE in the intraoperative setting has yet to be defined. Therefore, we performed intraoperative TEE examinations in 46 patients immediately before pulmonary embolectomy. TEE examinations were reviewed for signs of thromboemboli within the right, left, and main PA, and secondary signs of acute PA obstruction (right ventricular dysfunction, moderate-to-severe tricuspid regurgitation, leftward bowing of the interatrial septum). The definitive location of thromboemboli was determined from the surgical record. Echocardiographic evidence for the presence of PE was correctly demonstrated in 46% of all patients (n = 21 of 46). However, the sensitivity for direct visualization of thromboemboli at any specific location was only 26%. TEE was least sensitive for thromboemboli in the left PA (17%). TEE evidence of right ventricular dysfunction was observed in 96%, tricuspid regurgitation in 50%, and leftward interatrial septal bowing in 98% of examinations. Therefore, the use of intraoperative TEE to diagnose acute PE via direct visualization is limited. Indirect TEE evidence of PA obstruction may be helpful in supporting a diagnosis of PE.

Adult↗

Heart failure.

Explore the source record for details and available documents.

Cardiac Output, Low↗

Usefulness of intraoperative epiaortic echocardiography to resolve discrepancy between transthoracic and transesophageal measurements of aortic valve gradient - a case report.

PURPOSE: Intraoperative measurement of the aortic valve (AV) gradient in patients undergoing cardiac surgery is routinely performed using transesophageal echocardiography (TEE). In patients with severe aortic stenosis (AS), TEE Doppler beam alignment with the blood flow through the stenotic valve may be inaccurate, resulting in an underestimation of the AV gradient. We describe here the use of epiaortic echocardiography as an alternative to TEE for the intraoperative evaluation of AS. CLINICAL FEATURES: A patient diagnosed with severe AS (peak pressure gradient by transthoracic echocardiography: 108 mmHg) was undergoing AV replacement. In contrast, intraoperative TEE examination performed prior to bypass showed only a mild pressure gradient across the AV (peak pressure gradient: 38 mmHg). In order to resolve the conflicting information, epiaortic echocardiography was used to measure the AV gradient, confirming severe AS (peak pressure gradient: 98 mmHg). Most likely, Doppler beam alignment through the stenotic valve was more parallel to blood flow using epiaortic echocardiography, thus revealing the true pressure gradient. CONCLUSION: Intraoperative epiaortic measurement of AV gradients can be successfully performed in patients where TEE may be inaccurate due to difficulty in aligning a Doppler beam with the transvalvular blood flow.

Aortic Valve Stenosis↗

Perioperative myocardial ischemia reperfusion injury.

Myocardial I-R injury contributes to adverse cardiovascular outcomes after cardiac surgery. The pathogenesis of I-R injury is complex and involves the activation, coordination, and amplification of several systemic and local proinflammatory pathways (Fig. 4). Treatment and prevention of perioperative morbidity associated with myocardial I-R will ultimately require a multifocal approach. Combining preoperative risk stratification (co-morbidity and surgical complexity), minimizing initiating factors predisposing to SIRS, limiting ischemia duration, and administering appropriate immunotherapy directed toward systemic and local proinflammatory mediators of I-R injury, should all be considered. In addition, the role of the genetic-environmental interactions in the pathogenesis of cardiovascular disease is also being examined. Thus, in the near future, preoperative screening for polymorphisms of certain inflammatory and coagulation genes should inevitably help reduce morbidity by permitting the identification of high-risk cardiac surgical patients and introducing the opportunity for gene therapy or pharmacogenetic intervention [42,64].

Animals↗

Epicardial echocardiography: diagnostic utility for evaluating aortic valve disease during coronary surgery.

Intraoperative epicardial echocardiography is commonly used to evaluate the ascending aorta for atheromatous disease before cannulation and cross clamping. In addition, it may serve as a cardiac imaging technique in patients where placement of a transesophageal echocardiography (TEE) probe is contraindicated, probe advancement is difficult, or a TEE probe is not available. We report a patient who was taken to the OR for coronary artery bypass grafting. Intraoperative TEE was planned to evaluate aortic valve function. However, attempts to place a TEE probe were abandoned due to high resistance on probe insertion. Epicardial echocardiography revealed previously undiagnosed aortic valve disease resulting in replacement of this valve.

Aged↗

A practical approach to a comprehensive epicardial and epiaortic echocardiographic examination.

OBJECTIVE: More than a decade before the introduction of intraoperative transesophageal echocardiography (TEE), epicardial echocardiography was already in use as a diagnostic imaging modality to assist cardiac surgeons and anesthesiologists with clinical decision making. Although TEE has since become increasingly more popular, epicardial echocardiography may be the most convenient intraoperative imaging technique when TEE probe placement cannot be performed or is contraindicated. The authors developed a comprehensive examination protocol for the intraoperative interrogation of cardiac structures using an epicardial/epiaortic echocardiographic approach. DESIGN: Retrospective analysis of patient's medical records. SETTING: Single-center academic tertiary care hospital. PARTICIPANTS: Patients undergoing cardiac surgery. INTERVENTIONS: A total of 10 echocardiographic views were obtained for imaging cardiac structures, the ascending aorta, and proximal aortic arch. The described imaging planes permit the evaluation of ventricular performance, valvular function, cardiac structural abnormalities, and aortic disease. MEASUREMENTS AND MAIN RESULTS: A comprehensive epicardial/epiaortic echocardiographic examination was performed in 20 patients undergoing cardiac surgery requiring a full sternotomy. The described imaging planes were obtained in all patients in less than 8 minutes (range, 3.5-8 minutes; mean, 5.5 minutes). CONCLUSION: The present manuscript delineates a protocol for performing a comprehensive, intraoperative epicardial/epiaortic echocardiographic examination. Echocardiographic imaging planes of cardiac and aortic anatomy are described. This protocol may be useful for cardiac surgeons and anesthesiologists seeking to use this technique as a cardiac imaging modality that is complementary to TEE.

Aorta↗

Intraoperative assessment of diastolic function: utility of echocardiography.

PURPOSE OF REVIEW: This review discusses the current and future applications of different echocardiographic modalities in evaluating diastolic function intraoperatively. RECENT FINDINGS: Normal diastolic function is required for optimal cardiac performance. There is sufficient evidence to support the significant prevalence of preoperative diastolic dysfunction and its incidence following cardiac surgery, however controversy still exists regarding the impact of diastolic dysfunction on adverse outcomes. Echocardiography provides a relatively safe, practical and noninvasive means to evaluate perioperative diastolic function, however conventional measures may be limited by the impact of changes in heart rate, rhythm and loading conditions. Newer echocardiographic modalities are reportedly less sensitive to acute changes in loading conditions, and may therefore complement the use of conventional echocardiographic techniques in the perioperative period. SUMMARY: The availability of effective technology for diagnosing the presence and progression of perioperative diastolic function should assist in the identification of high-risk cardiac surgical patients who may benefit from appropriate triaging and therapeutic intervention.

Journal Article↗