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Intracranial hemorrhage (ICH) can be a devastating complication of extracorporeal life support (ECLS); however, studies on the timing of ICH detection by head ultrasound (HUS) are from 2 decades ago, suggesting ICH is diagnosed by day 5 of ECLS. Given advancements in imaging and critical care, our aim was to evaluate if the timing of ICH diagnosis in infants on ECLS support has changed. Patients6 months old undergoing ECLS 2011-2020 at a tertiary care children's hospital were included. Primary outcome was timing of ICH diagnosis on HUS. Seventy-four infants underwent ECLS for cardiac (54%) or pulmonary (46%) indications. Venoarterial ECLS was most common (88%). Median ECLS duration was 6 days (range 1-26). Sixteen patients were diagnosed with ICH (21.6%), at a median of 2 days postcannulation (range 1-4). Nearly all were4 weeks old at cannulation (93.8%). In conclusion, one-fifth of infants developed ICH diagnosed by HUS while on ECLS, all within the first 4 days of ECLS, consistent with previous literature. Despite advances in critical care and imaging technology, the temporality of ICH diagnosis in infants on ECLS is unchanged.

Background:Although rare, coronary artery anomalies can have significant clinical implications. Total anomalous origin of the coronary arteries from the pulmonary artery (TCAPA) represents a rare subtype of coronary artery anomaly for which little is known. The aim of this review was to characterise the presentation, utilised diagnostic modalities, associated cardiac lesions, and treatment strategies in patients with TCAPA.Methods:A systematic review was performed for cases of TCAPA using PubMed, Embase, and Web of Science. Keywords searched included “total anomalous origin of the coronary arteries from the pulmonary artery,” “single ostium anomalous coronary artery from the pulmonary artery,” and “anomalous origin of both coronary arteries from the pulmonary artery.”Results:Fifty-seven cases of TCAPA were identified in 50 manuscripts. Fifty-eight per cent of patients were male and the median age at presentation was 10 days (mean 1.71 ± 6.6 years, range 0 days–39 years). Most patients were symptomatic at the time of presentation; cyanosis (n = 22) and respiratory distress (n = 14) were the most common symptoms. Cases were most commonly diagnosed at autopsy (n = 26, 45.6%), but operative intervention was pursued in 22 cases (45.6%); aortic re-implantation (n = 14) and a Takeuchi-type repair (n = 7) were the most common routes of repair.Conclusions:The clinical presentation of patients with TCAPA was found to be variable, likely related to the presence of associated cardiac lesions. TCAPA should be considered in patients with suspected anomalous origin of the left coronary artery from the pulmonary artery for the serious consequences that can occur if not promptly corrected.

Anomalous origin of the circumflex or left anterior descending artery from the pulmonary artery (ACxAPA and ALADAPA, respectively) are rare congenital coronary anomalies with clinical presentation varying from an asymptomatic murmur to sudden cardiac arrest. A systematic review was performed, and 46 cases of ACxAPA and 51 cases of ALADAPA were identified in 87 articles. Data were collected and analyzed from each case. A better understanding of ACxAPA/ALADAPA can provide information to providers who encounter this lesion as well as provide insight into coronary artery development which may help in the understanding of coronary artery anomalies.

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Background Anomalous origin of the right coronary artery from the pulmonary artery (ARCAPA) is a rare congenital cardiac lesion that has been diagnosed in both children and adults with symptoms ranging from an asymptomatic murmur to sudden cardiac death. The aim of this review was to characterize published cases of ARCAPA to better understand this rare congenital coronary anomaly. Methods A systematic review was performed using PubMed, Embase, and Google Scholar for cases of ARCAPA. Keywords searched included: "anomalous origin of the right coronary artery from the pulmonary artery" and "ARCAPA." Results A total of 223 cases of ARCAPA were identified in 193 case reports. There was a slight male predominance (54.5%) and the median age at presentation was 14.0 years. Thirty-eight percent of patients were asymptomatic and most commonly identified during evaluation of a murmur. Angina and dyspnea were the most common presenting symptoms (22.4% and 17.0%, respectively). In symptomatic patients, a bimodal distribution of age at presentation was observed with a peak near birth and another between ages 40 and 60 years. The condition was most commonly diagnosed with coronary angiography (40.4%). Most cases were repaired surgically (72.6%) and reimplantation of the right coronary artery onto the aorta was the most common method of repair (62.3%). Conclusions ARCAPA represents a rare coronary anomaly with great variability in clinical presentation. An understanding of the pathophysiology associated with the lesion is critical when determining treatment strategies.

Background Multimodal pain management strategies are used for analgesia following pectus excavatum repair. However, the optimal regimen has not been identified. We describe our early experience with intercostal cryoablation for pain management in children undergoing the Nuss procedure and compare early cryoablation outcomes to our prior outcomes using thoracic epidural analgesia. Methods A multi-institutional, retrospective review of fifty-two patients undergoing Nuss bar placement with either intercostal cryoablation ( n =26) or thoracic epidural analgesia ( n =26) from March 2013 to January 2016 was conducted. The primary outcome was hospital length of stay. Secondary outcomes included telemetry unit monitoring time, total intravenous narcotic use, duration of intravenous narcotic use, and postoperative complications. Results Patients who underwent intercostal cryoablation had a significant reduction in the mean hospital length of stay, time in a monitored telemetry bed, total use of intravenous narcotics, and the duration of intravenous narcotic administration when compared to thoracic epidural patients. Cryoablation patients had a slightly higher rate of postoperative complications. Conclusion Intercostal cryoablation is a promising technique for postoperative pain management in children undergoing repair of pectus excavatum. This therapy results in reduced time to hospital discharge, decreased intravenous narcotic utilization, and has eliminated epidurals from our practice. Level of evidence Retrospective study – level III.

The natural history of pulmonary vascular disease associated with congenital heart disease (CHD) depends on associated hemodynamics. Patients exposed to increased pulmonary blood flow (PBF) and pulmonary arterial pressure (PAP) develop pulmonary vascular disease more commonly than patients exposed to increased PBF alone. To investigate the effects of these differing mechanical forces on physiologic and molecular responses, we developed two models of CHD using fetal surgical techniques: 1) left pulmonary artery (LPA) ligation primarily resulting in increased PBF and 2) aortopulmonary shunt placement resulting in increased PBF and PAP. Hemodynamic, histologic, and molecular studies were performed on control, LPA, and shunt lambs as well as pulmonary artery endothelial cells (PAECs) derived from each. Physiologically, LPA, and to a greater extent shunt, lambs demonstrated an exaggerated increase in PAP in response to vasoconstricting stimuli compared with controls. These physiologic findings correlated with a pathologic increase in medial thickening in pulmonary arteries in shunt lambs but not in control or LPA lambs. Furthermore, in the setting of acutely increased afterload, the right ventricle of control and LPA but not shunt lambs demonstrates ventricular-vascular uncoupling and adverse ventricular-ventricular interactions. RNA sequencing revealed excellent separation between groups via both principal components analysis and unsupervised hierarchical clustering. In addition, we found hyperproliferation of PAECs from LPA lambs, and to a greater extent shunt lambs, with associated increased angiogenesis and decreased apoptosis in PAECs derived from shunt lambs. A further understanding of mechanical force-specific drivers of pulmonary artery pathology will enable development of precision therapeutics for pulmonary hypertension associated with CHD.

Aim: To compare outcomes of continuous subcutaneous infusion of local anesthetic and epidural analgesia following the Nuss procedure. Patients & methods: A retrospective chart review compared patients managed with subcutaneous local anesthetic infusion (n = 12) versus thoracic epidural (n = 19) following the Nuss procedure from March 2013 to June 2015. Results: There was no difference in hospital length of stay or days on intravenous narcotics. Epidural catheter placement prolonged operating room time (146.58 ± 28.30 vs 121.42 ± 21.98 min, p = 0.01). Average pain scores were slightly higher in the subcutaneous infusion group (3.72 ± 1.62 vs 2.35 ± 0.95, p = 0.02), but of negligible clinical significance. Conclusion: Continuous subcutaneous infusion of local anesthetic could eliminate the need for thoracic epidural for pain management after the Nuss procedure.

Background Papillary muscle rupture in the fetus and neonate is a rare event that leads to severe mitral or tricuspid insufficiency and is associated with high perinatal mortality. We undertook surgical repair of this lesion in the neonatal period and report on our midterm results. Methods Three neonates with tricuspid insufficiency and 1 infant with mitral insufficiency, all due to papillary muscle or chordal rupture, underwent surgical repair with artificial chordal replacement and a modification of the de Vega annuloplasty technique that allowed external adjustment of the annulus size under transesophageal echocardiographic guidance after separation from cardiopulmonary bypass. Results All patients recovered well from the operation. There have been no late deaths and no valve-related complications. On discharge, all 3 patients had evidence of trace to mild atrioventricular valve regurgitation. At a median follow-up of 33 months (range, 7 to 50; 123 patient-months), all 4 patients are growing normally. Three patients have had no change in the degree of tricuspid or mitral regurgitation. One patient required reoperation at 54 months postoperatively for acute mitral insufficiency secondary to separation of an artificial chorda from the ventricular wall. Conclusions Surgical repair of critical neonatal tricuspid and mitral insufficiency associated with papillary muscle or chordal rupture is feasible and can result in good early and midterm results. Our modification of the De Vega annuloplasty technique with the ability to externally adjust the size of the annulus under echocardiographic guidance may improve the accuracy of the repair in the neonate.

Background A coronary artery arising from the wrong aortic sinus, with or without a proximal course between the aorta and the pulmonary artery, may predispose to myocardial ischemia, myocardial infarction, or sudden death. Methods We repaired this lesion in 5 symptomatic patients, all of whom had experienced exercise-related chest pain, dyspnea, or syncopal episodes. All patients underwent patch angioplasty of the proximal anomalous coronary artery with glutaraldehyde-treated autologous pericardium. When the coronary artery coursed between the aorta and the main pulmonary artery, the main pulmonary artery was translocated toward the left pulmonary artery to create additional space and prevent compression. Results All patients recovered well and to date have demonstrated no evidence of recurrent myocardial ischemia. Conclusions The combination of coronary artery angioplasty and translocation of the pulmonary artery seems to effectively address all the mechanisms that can generate ischemia.

The objective of this prospective, observational study with consecutive sampling was to assess the reliability, bias, and precision of Nellcor N-395 (N) and Masimo SET Radical (M) pulse oximeters in children with cyanotic congenital heart disease and children with congenital heart disease recovering from cardiopulmonary bypass-assisted surgery admitted to a cardiovascular operating suite and pediatric intensive care unit at a tertiary care community hospital. Forty-six children with congenital heart disease were studied in 1 of 2 groups: (1) those recovering from cardiopulmonary bypass with a serum lactic acid > 2 mmol/L, and (2) those with co-oximetry measured saturations (SaO 2) < 90% and no evidence of shock. Measurements of SaO 2 of whole blood were compared to simultaneous pulse oximetry saturations (SpO 2). Data were analyzed to detect significant differences in SpO 2 readout failures between oximeters and average SpO 2 - SaO 2 ± 1 SD for each oximeter. A total of 122 SaO 2 measurements were recorded; the median SaO 2 was 83% (57 - 100%). SpO 2 failures after cardiopulmonary bypass were 41% (25/61) for N versus 10% (6/61) for M ( P < .001). There was a significant difference in bias (ie, average SpO 2 - SaO 2) and precision (± 1 SD) between oximeters (N, 1.1 ± 3.3 vs M, -0.2 ± 4.1; P < .001) in the postcardiopulmonary bypass group but no significant difference in bias and precision between oximeters in the cyanotic congenital heart disease group (N, 2.9 ± 4.6 vs M, 2.8 ± 6.2; P = .848). The Nellcor N-395 pulse oximeter failed more often immediately after cardiopulmonary bypass than did the Masimo SET Radical pulse oximeter. SpO2 measured with both oximeters overestimated SaO2 in the presence of persistent hypoxemia.

Background Polytetrafluoroethylene (PTFE) and porcine small intestinal submucosa (pSIS) are patch materials used in congenital heart surgery. Porcine SIS is an extracellular-matrix scaffold that may interact with stem or progenitor cells. To evaluate this, we determined the in vitro effects of pSIS and PTFE on human bone marrow mesenchymal stromal cells (MSCs) and cardiac progenitor cells (CPCs) in 3 areas; cell proliferation, angiogenic growth-factor production, and differentiation. Methods Human MSCs and CPCs were seeded onto pSIS and PTFE patches. Cell-seeded patches were cultured and then assessed for cell viability and proliferation and supernatant vascular endothelial growth factor A (VEGFA) levels. Cell proliferation was quantified by MTT assay (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide). Quantitative real-time polymerase chain reaction was performed on cell-seeded scaffolds to determine relative changes in gene expression related to angiogenesis and cardiogenesis. Results The MSCs and CPCs were able to attach and proliferate on pSIS and PTFE. The proliferation rate of each cell type was similar on pSIS. Total RNA isolation was only possible from the cell-seeded pSIS patches. The MSC VEGFA production was increased by pSIS. Porcine SIS promoted an angiogenic gene profile in MSCs and an early cardiogenic profile in CPCs. Conclusions Both PTFE and pSIS allow for varying degrees of cell proliferation. Porcine SIS elicits different phenotypical responses in MSCs as compared with CPCs, which indicates that pSIS may be a bioactive scaffold that modulates stem cell activation and proliferation. These findings highlight the differences in scaffold material strategies and suggest potential advantages of bioactive approaches.

Background/Purpose: Hospital mortality rate among children with hypoplastic left heart syndrome (HLHS) after cardiac repair is well documented, but comparable data after noncardiac, surgical procedures are unknown. The authors hypothesized an increasing number of noncardiac procedures were being performed on children with HLHS, less than 2 years of age, from 1988 to 1997, and that these procedures were associated with a substantial mortality rate. Methods: A retrospective review of hospital discharge data for 2,457 children less than 2 years of age with HLHS for 1988 through 1997 was performed. The authors examined the outcomes of HLHS children undergoing only noncardiac surgical procedures during their hospital stay. Differences in hospital mortality rates between 1988 through 1992 versus 1993 through 1997 were assessed using the X 2 square statistic. Results: Nineteen percent of the 147 children with HLHS undergoing noncardiac, surgical procedures died (95% CI, 13% to 25%). Comparing the 2 study periods, there was no significant change in outcome among HLHS children undergoing noncardiac, surgical procedures (78% v. 83%; P >.1). There was no significant difference in the percentage of hospital discharges with noncardiac, surgical procedures performed per year. Conclusions: Although children with HLHS were not undergoing an increase in the number of noncardiac surgical procedures performed annually, even minor surgical procedures were associated with considerable mortality. Outcomes after noncardiac surgery in high-risk children with congenital heart disease warrant further investigation. J Pediatr Surg 37:1399-1403. Copyright 2002, Elsevier Science (USA). All rights reserved.

Objectives Cardiothoracic surgeons and practitioners of cardiovascular medicine have a long history of humanitarian aid. Although this is worthwhile at multiple levels and occasionally described in some detail, few efforts have a proven algorithm with demonstrable outcomes that suggest effective educational methodology or clinical results approaching accepted standards in developed countries.© 2014 The American Association for Thoracic Surgery Methods Our report provides a stepwise approach to developing highly successful self-sustainable, replicable, and scalable humanitarian congenital cardiac surgical programs, and provides data to allow insight into the efficacy of our model.Results This program model has evolved over 25 years, during which it has been replicated several times and scaled throughout a vast and populous country. Since 1989, Russia has undergone considerable social, political, and economic changes. Our program model proved successful throughout this time despite dynamic social, political, and medical landscapes.Conclusions The positive results of our program model indicate that these methodologies may be helpful to others attempting to address the worldwide shortage of cardiovascular care and particularly the complex interventions required in the management of congenital cardiovascular disease.

Background— The prevalence of Down syndrome (DS)–affected births has increased during the past 30 years; moreover, children with DS have a higher incidence of congenital heart disease compared with their peers. Whether children with DS have better or worse outcomes after repair of congenital heart disease is unclear. We sought to identify differences in in-hospital mortality after cardiac surgery in pediatric patients with and without DS using a large national database. Methods and Results— Children aged P P P P Conclusions— In this large national study, children with DS who underwent repair of congenital heart disease were more likely to survive to discharge than children without DS. Future work is needed to better understand the factors underlying these differences.

ObjectiveTo investigate the impact of probiotic Bifidobacterium longum ssp. infantis on the fecal microbiota and plasma cytokines in neonates with congenital heart disease.Study designSixteen infants with congenital heart disease were randomly assigned to receive either B. infantis (4.2 × 10(9) colony-forming units two times daily) or placebo for 8 weeks. Stool specimens from enrolled infants and from six term infants without heart disease were analyzed for microbial composition. Plasma cytokines were analyzed weekly in the infants with heart disease.ResultsHealthy control infants had increased total bacteria, total Bacteroidetes and total bifidobacteria compared to the infants with heart disease, but there were no significant differences between the placebo and probiotic groups. Plasma interleukin (IL)10, interferon (IFN)γ and IL1β levels were transiently higher in the probiotic group.ConclusionCongenital heart disease in infants is associated with dysbiosis. Probiotic B. infantis did not significantly alter the fecal microbiota. Alterations in plasma cytokines were found to be inconsistent.

OBJECTIVES: Surgical reconstructions or palliations of congenital heart defects often require the utilization of patches, of which the ideal material has yet to be discovered. Recently, porcine small intestinal submucosa extracellular matrix (SIS-ECM) has been advocated as an alternative to conventional synthetic or biological patch material. Here, we present our initial experience with SIS-ECM in paediatric cardiovascular reconstructions. METHODS: A retrospective review of all patients

A 13-year obese female with suspected viral myocarditis presented with acute decompensated heart failure. Due to her body habitus, she was a poor candidate for immediate heart transplantation. A peripherally inserted left ventricular assist device (LVAD) was implanted via the right axillary artery. Following device insertion the patient experienced rapid improvement in symptoms. The LVAD provided effective left ventricular unloading for 50 days, promoting myocardial recovery and maintaining excellent patient performance status. The device placement strategy allowed for a high level of activity including completion of school-work and participation in a weight loss program. The patient achieved a 28-pound weight loss, thus improving candidacy for transplantation. Removal of the device was well tolerated and post-removal echocardiography revealed an improvement in the left ventricular ejection fraction (LVEF) from 21% at baseline to 38% after device removal. This case represents a successful application of a peripherally inserted LVAD as a bridge to transplant in a pediatric patient with severe heart failure due to suspected viral myocarditis. For select patients with this condition, a transaxillary LVAD should be considered as a therapeutic option as it is well tolerated and provides effective left ventricle unloading to promote myocardial recovery and maintain performance status.

An infant boy was born at 40 weeks and 3 days of gestation with prenatal diagnoses of a congenital cystic adenomatoid malformation and left ventricular hypoplasia. Preoperative angiography showed right aortic arch, large right-sided patent ductus arteriosus (PDA), left pulmonary artery discontinuous from the main pulmonary artery, left PDA, and a collateral artery from the descending thoracic aorta to the left lower lung (Fig 1; arrow indicates left lung collateral artery). The patient was taken to the operating room for aortic arch reconstruction, unifocalization of the left pulmonary artery, and bilateral PDA ligation. Upon inspection there was a right aortic arch with discontinuous left pulmonary artery originating from the

Diagnosis and treatment of Candida albicans endocarditis can be difficult. We report a case of this rare condition in which a patient on oral fluconazole presented with septic pulmonary emboli without initial echocardiographic evidence of vegetation. Rapid attainment of a tissue diagnosis, along with combined medical surgical treatment proved to be effective for this patient.

We present a case report of a patient with conal septal hypoplasia (supracristal) ventricular septal defect (VSD) complicated by aortic insufficiency (AI) and subpulmonic stenosis from a fibrous membrane. The development of AI with VSD is a well-recognized problem. However, the association of VSD, AI, and significant right ventricular outflow tract obstruction (RVOTO) is less common. Mechanisms of RVOTO include prolapse of an aortic valve cusp across the VSD, as well as infundibular hypertrophy or muscle bundles. Technical echocardiographic issues can make the diagnosis of VSD, AI, and RVOTO challenging. The presence of a discrete fibrous subpulmonary membrane is uncommon in this setting. (J Am Soc Echocardiogr 2000;13:58-60.)

Coronary sinus thrombosis is an extremely rare clinical syndrome with a high fatality rate. It is associated with procedures in the right heart, including insertion of pacemaker wires, Swan-Ganz catheters, and central venous lines. Recognition is often late, and treatment options are not well characterized. We present a case of acute coronary sinus thrombosis and occlusion associated with electrophysiologic ablation for supraventricular tachycardia in an 11-year-old boy. He developed chest pain, ST elevation, a large pericardial effusion, and cardiogenic shock. Emergent cardiac catheterization and percutaneous intervention with rheolytic aspiration thrombectomy resulted in a dramatic recovery. With the advent of new technologies and procedures involving the right heart and coronary sinus, an appreciation of this potentially lethal complication and possible treatment strategies is important.

RISK OF INFECTION, AND ANTIBIOTIC PROPHYLAXIS, are topics that have been debated for decades by those involved in the care of children undergoing cardiac surgery. In this review we attempt to analyse what is known and what has been postulated about this subject. Suggestions regarding the best strategies for treatment have been formulated, based on published reports, as well as current practices worldwide.

Abiotrophia defectiva, one of several nutritionally variant Streptococcus species, is an uncommon but important cause of endocarditis in children. We describe an unusual case complicated by extensive aortitis with pits in the ascending aorta and the proximal aortic arch.

Pediatric patients who have preoperative hemodynamic instability or postoperative cardiac decompensation may frequently require the use of extracorporeal membrane oxygenation (ECMO) for stabilization of cardiac and respiratory function. While ECMO can be a therapeutic treatment for the congenital pediatric patient, it does not allow the additional functions of a complete cardiopulmonary bypass (CPB) circuit should subsequent surgical revision in the operating room be required. This paper will discuss our approach to converting the ECMO circuit to total cardiopulmonary bypass allowing the use of cardioplegia, cardiotomy suction, and modified ultrafiltration. This technique allows the conversion to CPB without ceasing support to the critically ill patient or exposing them to additional blood products or surface area in the priming of a new extracorporeal circuit. In addition, this circuit design allows for the resumption of ECMO support utilizing the same circuit if the patient necessitates it.

A 13-year-old Haitian girl presented with complex congenital heart disease consisting of transposition of the great arteries with total anomalous venous return. The patient exhibited clinical findings of long-standing congestive heart failure and cyanosis. She underwent complete repair with resolution of her symptoms.

Background . Tetralogy of Fallot with absent pulmonary valve (TOF/APV) is associated with pulmonary artery dilatation and airway compression. Methods . Since January 1, 1984, 28 patients with TOF/APV have undergone complete repair (median age 11 days, range 1 day to 16 years). Results . Thirteen patients were ventilated for respiratory failure preoperatively and extracorporeal membrane oxygenation was used in 3. Twenty-six patients underwent pulmonary artery plication (11 anterior, 15 anterior/posterior). The right ventricular outflow tract (RVOT) was reconstructed with a patch (19), valved conduit (5), or monocusp valve (4). Early mortality was 21.4% (6/28), with 1 late death. All early deaths occurred in infants intubated preoperatively. Survival was 77% (95% confidence limit [CL] 56%, 89%) at 1 year and 72% (95% CL 50%, 86%) at 10 years. After surgery, 3 patients underwent reoperation for persistent respiratory symptoms, which resolved after repeat plication and placement of a valved conduit. Freedom from death or reoperation was 68% (95% CL 46%, 83%) at 1 year and 52% (95% CL 29%, 71%) at 10 years. In a multivariable analysis, only preoperative intubation was associated with a worse outcome ( p = 0.04). Conclusions . Long-term outcome for patients with TOF/APV who survive the initial repair is good. Repeat plication and pulmonary valve implantation may improve outcome in patients with persistent airway compression.

We present erosion of a pectus bar through the sternum in a patient with Marfan syndrome. The complication as well as a novel technique for sternal reconstruction are reviewed.

In this report we demonstrate that ET-2, in addition to its powerful vasoconstrictor properties and its role in hypertension, is capable of creating a hypercoagulable (prothrombotic) state. This study was facilitated by the utilization of a sensitive modified recalcification time (MRT) test that can measure coagulation at all points in the coagulation spectrum. The MRT was determined on aliquots (1 ml) of citrated blood which were added to saline (MRTS), to 10 micrograms of endotoxin (MRTE), and to 10 pg of ET-2 (MRT ET-2). The mean values of MRTS, MRTE, and MRT ET-2 were 4.3 +/- 0.8, 3.7 +/- 1.0, and 3.9 +/- 0.8 min, respectively. There was a statistically significant difference between MRTE vs. MRTS and MRT ET-2 vs. MRTS using the two-tailed t-test (p0.02 and p0.005, respectively).

Platelet-activating factor (PAF) is known to activate platelets and thus promote clot formation in most mammalian species including humans. In this communication, the ability of PAF to hasten the overall coagulation process by measuring the recalcification time (RT) is described. Assessment of the RT in vitro indicated that the RT was significantly reduced by PAF (p0.001). This information adds a new dimension to the role of PAF in coagulation and also provides an exciting lead to the development of drugs for controlling the state of accelerated coagulation by pharmacologic means.