Long-term use of dual antiplatelet therapy for the secondary prevention of atherothrombotic events: Meta-analysis of randomized controlled trials

BACKGROUND

The potential benefit of long-term dual antiplatelet therapy (DAPT) for secondary prevention of atherothrombotic events is unclear. Data from different randomized controlled trials (RCT) using different agents in different subgroups showed inconsistent results.

METHODS

We performed a systematic review and meta-analysis from RCTs that tested different prolonged durations of DAPT for secondary prevention. Long term DAPT arm was defined as those receiving DAPT for more than 12months. Long-term aspirin arm was defined as those receiving either aspirin alone long term or DAPT for less than 12months.

RESULTS

The use of long term DAPT was associated with a significant decrease in composite of death, myocardial infarction (MI) and stroke (6.08% vs. 6.71%; odds ratio OR=0.86 [0.78-0.94]; P=0.001). This reduction of death, MI and stroke was mainly noticed in patients with prior MI or stroke, but not with PAD or multiple risk factors. The reduction was seen with post PCI patients with prasugrel and only in those with prior MI with clopidogrel and ticagrelor. Long-term use of DAPT was associated with significant increase in major bleeding (1.47% vs. 0.88%; OR=1.65 [1.23-2.21]; P=0.001).

CONCLUSION

Long-term use of DAPT for secondary prevention is associated with lower risk of death, MI and stroke beneficial especially in patients with prior MI and stroke, but it is associated with increased risk of bleeding. Prolonging DAPT requires careful assessment of the trade-off between ischemic and bleeding complications and should probably be reserved for patients with higher risk for atherothrombotic events.

Aortocoronary Saphenous Vein Graft Aneurysm with Fistula to the Right Atrium: Percutaneous Management of Surgical Complication

Aneurysmal dilatation of aortocoronary saphenous vein grafts (SVG) is a rare but known complication after coronary artery bypass grafting (CABG). They are most commonly found incidentally, although some may present with unstable angina or myocardial infarction (MI). Rarely, these aneurysms can develop into fistulas to the neighboring cardiac chambers. We report the case of a 66-year old woman with a history of CABG in 1996 with a left internal mammary artery (LIMA) graft to the left anterior descending and a SVG to distal right coronary artery presenting with non-ST segment elevation myocardial infarction (NSTEMI) complicated with congestive heart failure. Selective Coronary and Graft angiography showed an aneurysm in the mid SVG with a fistula into the right atrium (RA) resulting in a significant left to right shunt. The significant left to right shunt diverted blood flow from right coronary artery territory resulting in recurrent ischemia and angina and introduced a significant volume overload on the right ventricle resulting in over heart failure. Secondary to the course of LIMA graft along the sternum, surgery was not an option. Secondary to continued symptoms percutaneous intervention was performed with placement of two 6.0 x 50 mm Viabahn self-expanding covered stent with aggressive post-dilation resulting in successful closure with no residual flow. Percutaneous intervention is shown to be an effective approach to manage both aortocoronary fistula and grafts ruptures and is associated with better outcomes than surgical and conservative options. To the best of our knowledge, this is the first reported case of a successful closure of fistulous communication of a SVG aneurysm to the RA utilizing multiple peripheral covered stents.

Short, Intermediate and long term outcomes of CABG vs. PCI with DES in Patients With Multivessel Coronary Artery Disease. Meta-Analysis of Six Randomized Controlled Trials

OBJECTIVE

Comparing outcomes of percutaneous coronary intervention (PCI) with drug eluting stent (DES) and Coronary Artery Bypass Grafting (CABG) in patients with multivessel Coronary Artery Disease (CAD) using data from randomized controlled trials (RCT).

BACKGROUND

PCI and CABG are established strategies for coronary revascularization in the setting of ischemic heart disease. Multiple RCT have compared outcomes of the two modalities in patients with multivessel CAD.

METHODS

We did a meta-analysis from six RCT in the contemporary era comparing the effectiveness of PCI with DES to at 1 year, 2 years and 5 years respectively.

RESULTS

Compared to CABG, at one year PCI was associated with a significantly higher incidence of TVR (RR= 2.31; 95% CI: [1.80 - 2.96]; P=<0.0001), lower incidence of stroke (RR= 0.35; 95% CI: [0.19 - 0.62]; P=0.0003), and no difference in death (RR= 1.02; 95% CI: [0.77 - 1.36]; P= 0.88) or MI (RR= 1.16; 95% CI: [0.72 - 1.88]; P= 0.53). At 5 years, PCI was associated with a higher incidence of death (RR= 1.3; 95% CI: [1.10 - 1.54]; P= 0.0026) and MI (RR= 2.21; 95% CI: [1.75 - 2.79]; P=<0.0001). While the higher incidence of MI with PCI was noticed in both diabetic and non-diabetics, death was increased mainly in diabetic patients.

CONCLUSION

In patients with multi-vessel CAD, PCI with DES is associated with no significant difference in death or MI at 1 or 2 years. However at 5 years, PCI is associated with higher incidence of death and MI.

Comparative effectiveness of revascularization strategies in stable ischemic heart disease: current perspective and literature review

Percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) are established strategies for coronary revascularization in the setting of ischemic heart disease. Multiple randomized controlled trials and observational studies have compared the impact of the two modalities on the patients' quality of life, mortality and morbidity, as well as the cost-effectiveness of these modalities in different clinical setting. CABG is the preferred strategy for revascularizations in patients with multi-vessel disease, especially in those with higher risk secondary to associated diabetes, left ventricular dysfunction or more complex lesions. PCI is a reasonable revascularization modality in patients with ischemia and single or low-risk multi-vessel disease and those with unprotected left main with low complexity anatomy. Compared with PCI, CABG is associated with less repeat revascularization, better quality of life and improved survival in high-risk patients. Although CABG is associated with higher cost, it is probably associated with a reasonable cost per quality-adjusted life-year gained in many patients. Therefore, CABG will often be a cost-effective strategy, especially in patients with high angiographic complexity and/or diabetes.

Cost-effectiveness Assessment of Cardiac Interventions: Determining a Socially Acceptable Cost Threshold

Health care is a vital good for which there is an infinite demand. However, societal resources are finite and need to be distributed efficiently to avoid waste. Thus, the relative value of an intervention - cost compared to its effectiveness- needs to be taken into consideration when deciding which interventions to adopt. Cost-effectiveness analysis provides the crucial information which guides these decisions. As the field of medicine and indeed cardiology move forward with innovations which are effective but often expensive, it becomes imperative to employ these cost-effectiveness analytic tools, not with the intention of denying vital health services but to ascertain what the society willing to pay for.

Antiplatelet therapy in patients undergoing percutaneous coronary intervention: economic considerations

Percutaneous coronary intervention (PCI) is one of the most common medical procedures performed for treatment of coronary artery disease. Antiplatelet medications as adjunctive therapy for PCI are used routinely, with indications for specific agents or their combinations varying depending on the clinical scenario. While the cost-effectiveness of well-established agents has been extensively studied, newer drugs have not been evaluated as thoroughly. In addition, the clinical application of some antiplatelet drugs has recently changed, thus making older studies of cost effectiveness less applicable to the current landscape of clinical practice. This article reviews cost-effectiveness considerations of antiplatelet therapies in the treatment of coronary artery disease in patients undergoing PCI. Aspirin, P2Y12 inhibitors including clopidogrel and the newer agents prasugrel and ticagrelor, as well as glycoprotein (GP) IIb/IIIa inhibitors, are discussed. Overall, the use of dual antiplatelet therapy with aspirin and a P2Y12 inhibitor in patients undergoing PCI improves ischaemic outcomes and appears to be cost effective. The few available studies suggest that the recently approved medications prasugrel and ticagrelor are cost-effective alternatives to clopidogrel. However, no direct comparison between these two newer agents is available. The indications for GP IIb/IIIa inhibitors have changed in the current PCI era, and there is a paucity of cost-effectiveness data for their use in contemporary care.

Practical considerations of percutaneous ventricular assist devices

Percutaneous ventricular assist devices are increasingly used today, allowing the scope of left ventricular support to move out of the operating room and into the interventional suite and cardiovascular care unit. This has given patients requiring short-term therapy an opportunity to undergo high-risk procedures and provide a failing left ventricular support until native recovery can occur. A growing body of evidence exists that demonstrates device efficacy and safety, as well as its potential clinical importance, a topic that will be reviewed here. Additionally, many providers seek a resource for technical considerations and troubleshooting. We also aim to provide insight into such considerations.

Exercise blood pressure and future cardiovascular death in asymptomatic individuals

BACKGROUND

Individuals with exaggerated exercise blood pressure (BP) tend to develop future hypertension. It is controversial whether they have higher risk of death from cardiovascular disease (CVD).

METHODS AND RESULTS

A total of 6578 asymptomatic Lipid Research Clinics Prevalence Study participants (45% women; mean age, 46 years; 74% with untreated baseline BP <140/90 mm Hg [nonhypertensive]) performing submaximal Bruce treadmill tests were followed for 20 years (385 CVD deaths occurred). Systolic and diastolic BP at rest, Bruce stage 2, and maximal BP during exercise were significantly associated with CVD death. When we compared multivariate hazard ratios and 95% confidence intervals per 10/5-mm Hg BP increments, the association was strongest for rest BP (systolic, 1.21 [1.14 to 1.27]; diastolic, 1.20 [1.14 to 1.26]), then Bruce stage 2 BP (systolic, 1.09 [1.04 to 1.14]; diastolic, 1.09 [1.05 to 1.13]), then maximal exercise BP (systolic, 1.06 [1.01 to 1.10]; diastolic, 1.04 [1.01 to 1.08]). Overall, exercise BP was not significant after adjustment for rest BP. However, hypertension status modified the risk associated with exercise BP (P(interaction)=0.03). Among nonhypertensives, whether they had normal BP (<120/80 mm Hg) or prehypertension, Bruce stage 2 BP >180/90 versus < or =180/90 mm Hg carried increased risk independent of rest BP and risk factors (adjusted hazard ratio for systolic, 1.96 [1.40 to 2.74], P<0.001; diastolic, 1.48 [1.06 to 2.06], P=0.02) and added predictive value (net reclassification improvement, systolic, 12.0% [-0.1% to 24.2%]; diastolic, 9.9% [-0.3% to 20.0%]; relative integrated discrimination improvement, 14.3% and 12.0%, respectively).

CONCLUSIONS

In asymptomatic individuals, elevated exercise BP carried higher risk of CVD death but became nonsignificant after accounting for rest BP. However, Bruce stage 2 BP >180/90 mm Hg identified nonhypertensive individuals at higher risk of CVD death.

Representation of auditory signals in the M-cell: role of electrical synapses

The teleost Mauthner (M-) cell mediates a sound-evoked escape behavior. A major component of the auditory input is transmitted by large myelinated club endings of the posterior VIIIth nerve. Paradoxically, although nerve stimulations revealed these afferents have mixed electrical and glutamatergic synapses on the M-cell's distal lateral dendrite, paired pre- and postsynaptic recordings indicated most individual connections are chemically silent. To determine the sensory information encoded and the relative contributions of these two transmission modes, M-cell responses to acoustic stimuli in air were recorded intracellularly. Excitatory postsynaptic potentials (EPSPs) evoked by both short 100- to 900-Hz "pips" and longer-lasting amplitude- and frequency-modulated sounds were dominated by fast, repetitive EPSPs superimposed on an underlying slow depolarization. Fast EPSPs 1) have kinetics comparable to presynaptic action potentials, 2) are maximal on the distal lateral dendrite, and 3) are insensitive to GluR antagonists. They presumably are coupling potentials, and power spectral analysis indicated they constitute a high-pass signal that accurately tracks sound frequency and amplitude. The spatial profile of the slow EPSP suggests both proximal and distal dendritic sources, a result supported by predictions of a multicompartmental model and the effects of AMPAR antagonists, which preferentially reduced the proximal component. Thus a second class of afferents generates a portion of the slow EPSP that, with sound stimuli, demonstrate that the dominant mode of transmission at LMCE synapses is electrical. The slow EPSP is a dynamic, low-pass representation of stimulus strength. Accordingly, amplitude and phase information, which are segregated in other systems, are faithfully represented in the M-cell.

Baculovirus-mediated large-scale expression and purification of a polyhistidine-tagged rubella virus capsid protein

The capsid protein of rubella virus was produced in baculovirus-infected Spodoptera frugiperda insect cells, with a polyhistidine affinity tag at the carboxy terminus. The RV capsid recombinant protein was produced in a 10-liter bioreactor and purified, under nondenaturing conditions, using immobilized metal-ion affinity chromatography. Immunoblot analyses indicated that the purified recombinant protein was intact and migrated with the expected molecular weight. The final yield was 5 mg of purified protein per liter of cell culture. Surface plasmon resonance was used to investigate the antigenic potential of the histidine tagged capsid protein in an antigen-antibody interaction study. A specific interaction between the two proteins was shown. Our results suggest that this strategy should be useful in interaction studies of other virus-specific proteins and antibodies.

Synthesis of soluble rubella virus spike proteins in two lepidopteran insect cell lines: large scale production of the E1 protein

The two envelope glycoproteins of rubella virus (RV), E1 of 58 kDa and E2 of 42-47 kDa, were individually expressed in lepidopteran Spodoptera frugiperda as well as in Trichoplusia ni insect cells using baculovirus vectors. The authentic signal sequences of E1 and E2 were replaced with the honeybee melittin signal sequence, allowing efficient entrance into the secretory pathway of the insect cell. In addition, the hydrophobic transmembrane anchors at the carboxyl termini of E1 and E2 proteins were removed to enable secretion rather than maintenance in the cellular membranes. Synthesis of the recombinant proteins in the absence and presence of tunicamycin revealed that both E1 and E2 were glycosylated with apparent molecular weights of 52 kDa and 37 kDa, respectively. Recombinant E2 appeared to be partially secreted, whereas E1 was essentially found inside the infected insect cell. The E1 protein was produced in large scale using a 10-1 bioreactor and serum-free medium (SFM). Purification of the recombinant protein product was performed from cytoplasmic extracts by ammonium sulphate precipitation followed by Concanavalin A affinity chromatography. This type of purified recombinant viral glycoproteins may be useful not only in diagnostic medicine or for immunization, but should enable studies designed to solve the structure of the virus particle.

Phantom limb pain and etiology of amputation in unilateral lower extremity amputees

The relationships between phantom limb pain and both the etiology of amputation (blood clots, nonclot diabetes, and miscellaneous) and the occurrence of gangrene and/or infection were investigated in 92 unilateral lower extremity (LE) amputees who were seen sequentially. There were 55 above-knee (AK) and 37 below-knee (BK) amputations in 61 men and 31 women. The mean age was 51.4 years. The blood-clot etiology had the highest levels of phantom pain both pre- and postrehabilitation, the longest time interval between amputation and prosthetic fitting, and the greatest number of medical conditions. The nonclot diabetes and miscellaneous etiologies followed in order. A history of gangrene and/or infection was associated with higher levels of pain and longer time interval between amputation and prosthetic fitting.

Carpal tunnel syndrome: a clinicopathologic study

We evaluated 44 patients with carpal tunnel syndrome and performed histological evaluations of tenosynovium taken at the time of carpal tunnel release. Age, disease and work history, radiographs, and outcome were assessed. The clinical parameters were then compared with the histologic features to determine if the histology was predictive of the clinical course of carpal tunnel syndrome. We found no significance in the histologic changes in patients with carpal tunnel syndrome when age, duration of symptoms, work history, radiographs, and outcome were evaluated.

Preoperative radiation therapy and iododeoxyuridine for large retroperitoneal sarcomas

PURPOSE

Local failure is frequent after conventional therapy for patients with retroperitoneal sarcomas. A Phase I/II multimodality approach was used, combining iododeoxyuridine (IdUrd) and radiation therapy, followed by attempted surgical resection, with the goal of improving local control.

METHODS AND MATERIALS

Patients with retroperitoneal sarcomas were treated with three to five consecutive cycles of treatment. Each 14-day cycle consisted of a continuous intravenous infusion of IdUrd on days 1-5, twice a day radiation therapy (1.25 Gy/fraction) on days 8-12, and a break on day 13 and 14. Surgical resection was attempted after three or five cycles. Patients resected after three cycles received an additional two cycles of treatment with radiation directed to the tumor bed. IdUrd dose was escalated in Phase I fashion (1000 mg/m2/day, 1333 mg/m2/day, and 1600 mg/m2/day). The median potential follow-up was 31 months.

RESULTS

Sixteen patients (13 with high grade tumors) were treated. The median maximum tumor size was 17 cm. Resection margins were negative in four patients, microscopically positive in four patients, and grossly positive in three patients. Five patients were not resected. The only grade 4 acute toxicity observed was vomiting which occurred in three patients receiving upper abdominal radiation. Postsurgical and long-term complications were rare. Median survival overall and for resected patients were 18 and 32 months, respectively. Local control was observed in three out of four patients with negative margins (9, 40+, and 51+ months), two out of four patients with microscopically positive margins (4 and 22 months), and one out of three patients with grossly positive margins (46+ months). The overall freedom from local progression was 45% at 24 months.

CONCLUSION

Retroperitoneal sarcomas can be resected after preoperative radiation therapy and IdUrd, with encouraging local control in patients resected with negative or microscopically positive margins. The recommended dose using this drug and radiation schedule appears to be 1600 mg/m2/day, which will form the basis for a Phase II trial.

Large-scale propagation of insect cells

Cultured insect cells have many uses in agriculture and medicine. They can be used in the diagnosis and isolation of a number of viruses infecting both animals and plants and for the laboratory study of these viruses. Large-volume culture of insect cells has been envisioned as a way of producing viruses for use in controlling insect pests and for the production of viral antigens for vaccine preparations. Recently they have become a potentially valuable way of producing a variety of proteins for human and veterinary medicine using the genetically engineered baculovirus expression vectors. The development of satisfactory cell lines and culture methods has proceeded at a slow, irregular pace, inhibited by the lack of knowledge of the physiology of the insect, its small size, and often by the lack of consistent, adequate support for the necessary developmental research. However, now that the basic culture systems are available, cell lines have been developed or can easily be developed for most needs. Suitable media are available and recent developments in refining existing media formations have resulted in low-cost media containing little protein to interfere with down-stream processing of cellular metabolites. Future developments are likely to further improve the media formulations and lower the cost. Technical problems relating to oxygen demand and cell fragility that inhibited the continued development of large-volume culture systems beyond the laboratory a few years ago now appear to be solved or at least are solvable. The successful culture of the Spodoptera cells in bioreactors of 40-liter capacity indicates that means of producing insect cells or their metabolic products on a commercial scale can be made economically feasible.

Herpesvirus simiae (B virus): replication of the virus and identification of viral polypeptides in infected cells

The events and products of replication of Herpesvirus simiae (B virus) in Vero cells were studied. The time course of the synthetic events of DNA replication and protein synthesis were found to be similar to the processes of the herpes simplex viruses and SA 8. Infectious progeny virus were detected by 4 hours post infection and were first found extracellularly between 6 and 8 hours post infection (PI). As in the case of SA 8, all cell lines tested were permissive for lytic infection by B virus. Analyses of B virus-infected cells by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) revealed approximately 50 infected cell polypeptides (ICP) ranging in molecular weight from about 26,000 to 239,000 daltons. The kinetics of synthesis of the ICPs were also identified. At least nine glucosamine-containing glycopeptides were noted ranging from 133,000 to 29,000 daltons.

Effect of aluminum chloride and zinc sulfate on Autographa california nuclear polyhedrosis virus (ACNPV) replication in cell culture

When IPL-SF-21AE III continuous insect cell line was grown and maintained in IPL-41 insect cell culture medium supplemented with 16 microM of AlCl3 or 0.24 microM of ZnSO4 . 7H2O, or both metallic salts, and then infected with Autographa california nuclear polyhedrosis virus, virus replication was increased significantly. The yield of polyhedral inclusion bodies (PIB) was enhanced up to 121%. Synthesis of cell-free nonoccluded virus was increased to 365% when infectivity was assayed by the plaque method. Newly applied electron microscopic quantitation and stereological techniques also revealed a significant increase in virus particles (VP) and in amount and size of PIB as well as number of VP per PIB.

Chemical inhibition of foamyvirus in primary baboon (Papio cynocephalus) kidney cells

This report describes the conditions for the use of aluminum chloride (AlCl3) in growth and maintenance media for the suppression or inhibition of simian foamyviruses (SFV) in primary baboon kidney (BAK) and rabbit kidney (RK) cell cultures. When RK cells were planted in medium containing AlCl3, infected with SFV, and passaged, the growth of SFV was suppressed or inhibited by the presence of AlCl3. With this method, BAK cells yielded higher viral titers after infection with various viruses, thus making these cells more suitable for virological applications.

Improved replication of Autographa californica nuclear polyhedrosis virus in roller bottles: characterization of the progeny virus

A reproducible growth curve was established for the propagation of Autographa californica (Speyer) nuclear polyhedrosis virus (ACMNPV) In a continuous insect line from Spodoptera frugiperda (J. E. Smith) during large-volume production. A newly developed method for quantitation of polyhedra inclusion bodies (PIB) by electron microscopy (EM) during the growth cycle was compared to hemocytometer counts. The virus particles (VP) ratio to PFU and VP per PIB were established by EM methods. Optimal yields of PIB and cell-free virus with biological activities were obtained in six consecutive production lots when the growth curve conditions were followed. The DNA of the viruses produced in the 1st and 8th passages in the S. frugiperda cell line was treated with restriction endonucleases and compared with that from the E-2 cloned variant of this virus. Data confirmed that the virus was the ACMNPV and also indicated that there were no detectable changes after 8 passages in insect cell culture.

Chemically defined serum-free media for the cultivation of primary cells and their susceptibility to viruses

Chemically defined media SFRE-199-1 for the growth and SFRE-199-2 for the maintenance of primary baboon kidney (Bak) cell cultures were formulated by supplementing medium M199 with insulin, sodium pyruvate, zinc sulfate, and increasing arginine-HCl, cysteine, cystine, L-glutamine, L-glutamatic acid, glycine, histidine, tyrosine, and glucose to maximally active nontoxic concentrations. For prolonged maintenance of the cells, physiological pH control, and blocking of excessive lactic acid accumulation in the spent medium of the cell cultures, it is necessary to supplement the medium containing Earle's balanced salts with D-(+)galactose. The cells grew and were maintained equally well on glass or polystyrene surfaces. Selenium, when added to growth medium or substituted for insulin and zinc sulfate, did not stimulate cell growth. Electron microscopy showed that numerous dense particles, approximately 250 to 400 A in diameter, with the appearance of glycogen, were found throughout the cytoplasm in the cells grown in SFRE-199-1 and maintained in SFRE-199-2. Echovirus types 1 to 3, poliovirus types 1 to 3, coxsackievirus types B2, B4, B5, Herpes-virus hominis type 1, simian herpesvirus H. simiae and SA8, and simian adenovirus SV34 when titrated in primary Bak cells and grown and maintained in SFRE-199-1 and 2, respectively, developed titers comparable to those obtained in conventionally grown and maintained cells.

Concentration of baboon endogenous virus in large-scale production by use of hollow-fiber ultrafiltration technology

A process is described in which the baboon endogenous virus (BaEV) is produced under optimum conditions in cell culture, and concentrated by hollow-fiber ultrafiltration technology under conditions of large-scale production. This system has advantages over conventional systems in that the flow rate is increased 2.5-fold during concentration. Thermal inactivation of BaEV was retarded by the addition of lactose glutamate to the harvested tissue culture fluid. After concentration, at least 91% of the virus RNA-directed DNA polymerase is recovered with a concomitant increase in infectious virus. Materials needed for modifying described systems may be obtained from commercial sources.

The isolation of herpesvirus from trigeminal ganglia of normal baboons (Papio cynocephalus)

A herpesvirus was isolated from the trigeminal ganglia of three of six normal baboons (Papio cynocephalus). This virus possessed the virologic characteristics of SA8, A herpesvirus known to be indigenous to the baboon.

Gliomatosis cerebri. Report of four cases and review of the literature

Four cases of gliomatosis cerebri are reported that demonstrate the variability of the clinical course. A review of these and 32 cases from the literature revealed that the most striking finding was change in personality and mental status. Hemiparesis, ataxia, papilledema, headache, seizure, and brainstem signs were the next most common clinical findings. Laboratory and radiographic tests, including angiography and pneumoencephalography, often showed only minor and nonspecific changes in the face of profound mental deterioration. Increased intracranial pressure usually occurred late but was probably an important factor of the terminal course in most patients. The pathologic changes were typical, with diffuse infiltration of astrocytoma cells through brain stem, subcortical white matter, and, to a lesser extent, cerebral cortex.