Territorial scent-marking effects on vigilance behavior, space use, and stress in female Columbian ground squirrels

Social environments can profoundly affect the behavior and stress physiology of group-living animals. In many territorial species, territory owners advertise territorial boundaries to conspecifics by scent marking. Several studies have investigated the information that scent marks convey about donors' characteristics (e.g., dominance, age, sex, reproductive status), but less is known about whether scents affect the behavior and stress of recipients. We experimentally tested the hypothesis that scent marking may be a potent source of social stress in territorial species. We tested this hypothesis for Columbian ground squirrels (Urocitellus columbianus) during lactation, when territorial females defend individual nest-burrows against conspecifics. We exposed lactating females, on their territory, to the scent of other lactating females. Scents were either from unfamiliar females, kin relatives (a mother, daughter, or sister), or their own scent (control condition). We expected females to react strongly to novel scents from other females on their territory, displaying increased vigilance, and higher cortisol levels, indicative of behavioral and physiological stress. We further expected females to be more sensitive to unfamiliar female scents than to kin scents, given the matrilineal social structure of this species and known fitness benefits of co-breeding in female kin groups. Females were highly sensitive to intruder (both unfamiliar and kin) scents, but not to their own scent. Surprisingly, females reacted more strongly to the scent of close kin than to the scent of unfamiliar females. Vigilance behavior increased sharply in the presence of scents; this increase was more marked for kin than unfamiliar female scents, and was mirrored by a marked 131% increase in free plasma cortisol levels in the presence of kin (but not unfamiliar female) scents. Among kin scents, lactating females were more vigilant to the scent of sisters of equal age, but showed a marked 318% increase in plasma free cortisol levels in response to the scent of older and more dominant mothers. These results suggest that scent marks convey detailed information on the identity of intruders, directly affecting the stress axis of territory holders.

Molecular dynamics study of nanoconfined TIP4P/2005 water: how confinement and temperature affect diffusion and viscosity

In the past few decades great effort has been devoted to the study of water confined in hydrophobic geometries at the nanoscale (tubes and slit pores) due to the multiple technological applications of such systems, ranging from drug delivery to water desalination devices. To our knowledge, neither numerical/theoretical nor experimental approaches have so far reached a consensual understanding of structural and transport properties of water under these conditions. In this work, we present molecular dynamics simulations of TIP4P/2005 water under different nanoconfinements (slit pores or nanotubes, with two degrees of hydrophobicity) within a wide temperature range. It has been found that water is more structured near the less hydrophobic walls, independently of the confining geometries. Meanwhile, we observe an enhanced diffusion coefficient of water in both hydrophobic nanotubes. Finally, we propose a confined Stokes-Einstein relation to obtain the viscosity from diffusivity, whose result strongly differs from the Green-Kubo expression that has been used in previous works. While viscosity computed with the Green-Kubo formula (applied for anisotropic and confined systems) strongly differs from that of the bulk, viscosity computed with the confined Stokes-Einstein relation is not so much affected by the confinement, independently of its geometry. We discuss the shortcomings of both approaches, which could explain this discrepancy.

PLA2G6 mutations associated with a continuous clinical spectrum from neuroaxonal dystrophy to hereditary spastic paraplegia

PLA2G6-associated neurodegeneration (PLAN) and hereditary spastic paraplegia (HSP) are 2 groups of heterogeneous neurodegenerative diseases. In this study, we report PLA2G6 gene mutations in 3 families from Turkey, Morocco, and Romania. Two affected Turkish siblings presenting HSP adds the disease to PLAN phenotypes. They were homozygous for the PLA2G6 missense c.2239C>T, p.Arg747Trp variant and the ages of onset were 9 and 21. Parkinsonism, dystonia or cognitive decline were not the clinical elements in these patients contrary to the cases that has been previously reported with the same variant, however, iron accumulation was evident in their cranial magnetic resonance imaging. The Moroccan patient was homozygous for a novel missense c.1786C>T, p.Leu596Phe variant and the Romanian patient had 2 novel mutations; c.1898C>T, p.Ala633Val and c.1765_1768del, p.Ser589ThrfsTer76. Both of these patients conformed better to childhood onset PLAN with the age of onset at 4 and 7 years, respectively. Interestingly, all identified mutations were affecting the highly conserved patatin-like phospholipase domain of the PLA2G6 protein.

Effect of passive heat stress on arterial stiffness in smokers versus non-smokers

In non-smokers, passive heat stress increases shear stress and vasodilation, decreasing arterial stiffness. Smokers, who reportedly have arterial dysfunction, may have similar improvements in arterial stiffness with passive heat stress. Therefore, we examined the effects of an acute bout of whole-body passive heat stress on arterial stiffness in smokers vs. non-smokers. Thirteen smokers (8.8 ± 5.5 [median = 6] cigarettes per day for > 4 years) and 13 non-smokers matched for age, mass, height, and exercise habits (27 ± 8 years; 78.8 ± 15.4 kg; 177.6 ± 6.7 cm) were passively heated to 1.5 °C core temperature (T C) increase. At baseline and each 0.5 °C T C increase, peripheral (pPWV) and central pulse wave velocity (cPWV) were measured via Doppler ultrasound. No differences existed between smokers and non-smokers for any variables (all p >  .05), except cPWV slightly increased from baseline (526.7 ± 81.7 cm · s(-1)) to 1.5 °C ΔT C (579.7 ± 69.8 cm · s(-1); p < 0.005), suggesting heat stress acutely increased central arterial stiffness. pPWV did not change with heating (grand mean: baseline = 691.9 ± 92.9 cm · s(-1); 1.5 °C ΔT C = 691.9 ± 79.5 cm · s(-1); p > 0.05). Changes in cPWV and pPWV during heating correlated (p < 0.05) with baseline PWV in smokers (cPWV: r = -0.59; pPWV: r = -0.62) and non-smokers (cPWV: r = -0.45; pPWV: r = -0.77). Independent of smoking status, baseline stiffness appears to mediate the magnitude of heating-induced changes in arterial stiffness.

Use of nested flow models and interpolation techniques for science-based management of the Sheyenne National Grassland, North Dakota, USA

Noxious weeds threaten the Sheyenne National Grassland (SNG) ecosystem and therefore herbicides have been used for control. To protect groundwater quality, the herbicide application is restricted to areas where the water table is less than 10 feet (3.05 m) below the ground surface in highly permeable soils, or less than 6 feet (1.83 m) below the ground surface in low permeable soils. A local MODFLOW model was extracted from a regional GFLOW analytic element model and used to develop depth-to-groundwater maps in the SNG that are representative for the particular time frame of herbicide applications. These maps are based on a modeled groundwater table and a digital elevation model (DEM). The accuracy of these depth-to-groundwater maps is enhanced by an artificial neural networks (ANNs) interpolation scheme that reduces residuals at 48 monitoring wells. The combination of groundwater modeling and ANN improved depth-to-groundwater maps, which in turn provided more informed decisions about where herbicides can or cannot be safely applied.

The impact of balloon aortic valvuloplasty on aortic regurgitation in patients with severe aortic stenosis

BACKGROUND AND AIM OF THE STUDY

Severe aortic regurgitation (AR) is a contraindication for balloon aortic valvuloplasty (BAV). As the effects of mild and moderate AR are unknown, the study aim was to determine the effects of BAV in patients with mild and moderate AR.

METHODS

A total of 263 consecutive patients with symptomatic severe aortic stenosis (AS) who underwent BAV was included in the study. The patients were stratified into three groups according to their pre-procedural degree of AR, as assessed echocardiographically.

RESULTS

The study groups included pre-BAV with no AR (n = 76; 28.9%), mild AR (n = 180; 68.4%), and moderate AR (n = 7; 2.7%). There were no differences in the baseline characteristics of the groups, with a mean age of 81.9 +/- 9.0 years and a Society of Thoracic Surgeons score of 12.9 +/- 6.0. Among patients with no AR pre-BAV, 48.7% developed mild AR post-BAV, while 4.5% of those with mild AR pre-BAV developed moderate AR (p < 0.001). The majority of patients (93%) had mild AR both pre- and post-BAV. Only two patients developed severe AR post-BAV. A good agreement existed between the categories of AR pre- and post-BAV (weighted kappa = 0.54, 95% CI, 0.43-0.65). The degree of AR post-BAV did not impact on the mortality rates of mild AR (41.1%), moderate AR (46.9%), or severe AR (63.6%) (p = 0.31).

CONCLUSION

It is safe to perform BAV in patients with mild and moderate AR. About half of all patients with no AR may develop mild AR, the majority will remain in mild AR, and a small percentage will develop moderate or severe AR.

In-plane pyridinium cation reorientation in bis-thiourea chloride, bromide and iodide: quasielastic neutron scattering combined with molecular dynamics simulations

We have studied the dynamics of bis-thiourea pyridinium chloride and bromide by means of quasielastic neutron scattering (QENS). The QENS data allow describing the geometry of the in-plane motion of the pyridinium cation and reveal that it is similar to the motion previously observed in bis-thiourea pyridinium iodide. Molecular dynamics (MD) simulations have been performed to investigate the cation dynamics on the high temperature phase of the full series of compounds: bis-thiourea pyridinium chloride, bromide and iodide. Three different models of intermolecular potential have been tested and the agreement between the simulated and experimental elastic incoherent structure factors (EISFs) is used to select the more realistic one. The detailed analysis of the MD results indicates that Coulombic interactions together with the formation of hydrogen bonds between the pyridinium cation and the host sublattice influence strongly the geometry of the in-plane cation reorientation.

Characteristics of adult stem cells

Stem cells are characterized by their unlimited ability to divide specifically; a stem cell is capable of making an immense number of copies of itself, maintaining the same characteristics. Moreover, these cells are able to generate several of the cell lineages which make up the body, including cells from the heart, liver, kidney, neurons, and muscles. Investigation of the mechanisms through which this differentiation occurs, the genes involved and the possibility of increasing the efficiency with which stem cells can be isolated and/or characterized are currently among the most important fields in biology and biomedicine.To date, stems cells have been identified from four different sources: Embryonic stem cells (ESC), germinal stem cells, and those derived from embryonic carcinomas (teratocarcinomas) and from somatic tissues (somatic stem cells). The latter are called adult stem cells (ASC) when they are found in postnatal tissues. We now know that there is a great diversity among ASC, with some tissues, such as the bone marrow, containing more than one type of ASC. Adult stem cells have several characteristics that make them to be the main players in current regenerative medicine and are being investigated as potential therapeutic agents for a wide variety of diseases. Specifically, HSC and MSC are being assessed in increasing numbers of clinical trials.

Correlation between fractional flow reserve and intravascular ultrasound lumen area in intermediate coronary artery stenosis

AIMS

Fractional flow reserve (FFR) of <0.8 or 0.75 is currently used to guide revascularisation in lesions with intermediate coronary stenosis. We assessed whether there is an intravascular ultrasound (IVUS) measurement that can reliably be used to predict when patients should undergo intervention.

METHODS AND RESULTS

The analysis included 92 intermediate lesions (84 patients) located in vessel diameters >2.5 mm. Positive FFR was considered present at <0.8 and 0.75. IVUS minimum lumen area (MLA) was correlated to the FFR findings in intermediate lesions with 40-70% stenosis. The mean FFR value was 0.89 ± 0.08. Twenty-four patients (26.1%) had FFR <0.8; 17 (18.5%) <0.75. Positive correlations between FFR and IVUS measurements included MLA (r = 0.34, p<0.001), minimum lumen diameter (MLD) (r=0.31, p=0.004), lesion length (r=-0.5, p<0.001), and area stenosis (r=-0.31, p=0.01). There was no significant correlation between FFR and quantitative coronary angiography in MLD (r=0.19, p=0.06), diameter stenosis (r=0.08, p=0.4), or lesion length (r=-0.14, p=0.17). A receiver operating characteristic curve identified MLA <2.8 mm2 (sensitivity 79.7%, specificity 80.3%) as the best threshold value for FFR <0.75; and MLA <3.2 mm2 as best for FFR <0.8 (sensitivity 69.2%, specificity 68.3%).

CONCLUSIONS

Anatomic measurements of intermediate coronary lesions obtained by IVUS show a moderate correlation to FFR values, although they differ according to vessel size. IVUS MLA may be used as an alternative to FFR when assessing the need for intervention in intermediate coronary lesion. Vessel size, however, should always be taken into account.

Molecular dynamics simulation of cation dynamics in bis-thiourea pyridinium nitrate inclusion compound

Molecular dynamics simulations have been performed on the high temperature phase of the bis-thiourea pyridinium nitrate inclusion compound. Three different potential models have been tested. In the three cases, the analysis of the centre of mass motion of pyridium cations indicates that they do not diffuse along the channels. However, only the potential including a specific hydrogen bonding interaction provides a description of the in-plane cation reorientation in reasonable agreement with the experimental results deduced from quasielastic neutron scattering (QENS) measurements. This model shows that the pyridinium cation reorients among three non-equivalent positions and gives reorientational correlation times comparable to those extracted from the QENS data. We conclude that the particular geometry of this reorientation is due to the formation of hydrogen bonds of different strength between the pyridinium cation of the guest sublattice and the host sublattice.

Hybrid strategy of a bare metal stent combined with a drug-eluting stent versus exclusive drug-eluting stent implantation for multivessel percutaneous coronary intervention

AIMS

This study aimed to examine the strategy of hybrid percutaneous coronary intervention (PCI) -bare metal stent (BMS) and drug-eluting stent (DES)- versus exclusive DES implantation for patients undergoing multivessel PCI.

METHODS AND RESULTS

A cohort of 2,065 patients who underwent PCI (698 hybrid, 1,367 exclusive DES) were followed clinically up to one year. The primary outcome was target vessel revascularisation-major adverse cardiac events (TVR-MACE). Patients presenting with cardiogenic shock, anaemia (haematocrit <25), and bypass graft PCI were excluded. Only patients with ≥ 2 stents in two different lesions were analysed for this study. Baseline and procedural characteristics were similar. Major in-hospital complications and subacute stent thrombosis rates were similar. At one year, there was no difference in TVR-MACE (hybrid 17.2% vs. DES 14.6%, p=0.128). On multivariable analysis, hybrid PCI was not a predictor of TVR-MACE. The strongest predictors of TVR-MACE at one year were hypertension and African American race. Cumulative stent thrombosis rates at one year were similar in both groups.

CONCLUSIONS

Patients who undergo hybrid PCI have similar composite in-hospital and 1-year outcomes as those who undergo exclusive DES PCI. The hybrid stent approach should be considered for patients with multivessel PCI since it can lower the procedure cost without increasing adverse events.

Cellular video-phone assisted transmission and interpretation of prehospital 12-lead electrocardiogram in acute st-segment elevation myocardial infarction

BACKGROUND

Prehospital 12-lead electrocardiogram (ECG) reduces the time to reperfusion in acute ST-segment elevation myocardial infarction (STEMI). However, the reliability of using cellular video-phone (VP) assisted interpretation of ECG is unknown.

METHODS

We studied the interphysician reliability in interpreting the ECG assisted with VP compared to print ECG interpretation. Twenty-seven physicians prospectively interpreted the ECG transmitted from the field in real-time using VP and later using the same printed ECG. The time to completion, accuracy of interpretation, and physician rating of the VP technology were recorded.

RESULTS

Similar high interphysician reliability was observed with both VP assisted and printed ECG interpretation including presence of ST-segment elevation (intraclass correlation coefficient [ICC]= 0.98 [95% CI 0.96-1] vs. 0.99 [95% CI 0.99-1]) and pathologic Q wave (ICC = 0.99 [95% CI 0.98-1] vs. 1 [95% CI 1]), respectively. The mean time to transmit and interpret the ECG with VP versus printed ECG was 3.9 ± 1.9 versus 2.1 ± 0.9 minutes, respectively, P < 0.01. On a scale of 1 to 5 with 5 being the best, the average rating of VP ease of use was 4.4 ± 0.5 and utility to recommend treatment was rated a 5.

CONCLUSION

Cellular VP-assisted transmission and interpretation in real-time of prehospital ECG has high interphysician reliability, similar to the printed ECG interpretation. Future studies testing whether VP decreases the ischemic time and expedites the reperfusion of STEMI patients are needed.

Outcomes after unrestricted use of everolimus-eluting stent compared to paclitaxel- and sirolimus-eluting stents

Compared to paclitaxel-eluting stents (PESs) and sirolimus-eluting stents (SESs), a paucity of data exists regarding the clinical outcome of everolimus-eluting stents (EESs) in unselected patients with the entire spectrum of obstructive coronary artery disease. The present study cohort included 6,615 consecutive patients at Washington Hospital Center who underwent coronary artery stent implantation with EESs (n = 519), PESs (n = 2,036), or SESs (n = 4,060). Patients who received bare metal stents, zotarolimus-eluting stents, or 2 different drug-eluting stent types were excluded. The analyzed clinical end points were death, death or Q-wave myocardial infarction, target lesion revascularization (TLR), target vessel revascularization, definite stent thrombosis, and major adverse cardiac events, defined as the composite of death, Q-wave myocardial infarction, or TLR at 1 year. The groups were well matched for the conventional risk factors for coronary artery disease, except for systemic hypertension, which differed among the groups. The unadjusted end points for EESs and PESs were death (4.5% vs 7.1%; p = 0.03), TLR (3.4% vs 4.6%; p = 0.24), target vessel revascularization (5.6% vs 7.1%; p = 0.46), death or Q-wave myocardial infarction (4.5% vs 7.4%; p = 0.02), and definite stent thrombosis (0.0% vs 0.7%; p = 0.09). The unadjusted end points for EES and SES were death (4.5% vs 5.2%; p = 0.45), TLR (3.4% vs 5.8%; p = 0.3), target vessel revascularization (5.6% vs 8.6%; p = 0.05), death or Q-wave myocardial infarction (4.5% vs 5.4%; p = 0.39), and definite stent thrombosis (0.0% vs 1.08%; p = 0.003). The rates of major adverse cardiac events were similar among the 3 groups. After multivariate analysis, the rate of death or Q-wave myocardial infarction between the EES and PES groups was no longer significant (hazard ratio 1.14, 95% confidence interval 0.59 to 2.20, p = 0.70). In conclusion, the results of the present study suggest the use of EES in routine clinical practice is both safe and effective but offers no clinically relevant advantage in terms of hard end points compared to PES or SES.

Sirolimus-eluting stents versus paclitaxel-eluting stents in patients with chronic renal insufficiency

BACKGROUND

Chronic renal insufficiency (CRI) is associated with an increased incidence of restenosis and stent thrombosis. Drug-eluting stents (DES), when compared to bare metal stents (BMS), reduce the incidence of restenosis in these patients. This study aimed to examine whether there are differences in clinical outcome after implantation of sirolimus-eluting stents (SES) versus paclitaxel-eluting stents (PES) in patients with CRI who are subjected to coronary intervention.

METHODS

A cohort of 570 patients with CRI who underwent intervention with DES (346 with SES and 224 with PES) were followed clinically up to 1 year and the clinical events were recorded and compared between groups.

RESULTS

Baseline and procedural characteristics were similar, with a slightly higher number of diseased vessels in the SES group as compared to the PES group (2.3 +/- 0.9 vs 2.1 +/- 0.9, P = 0.06). The overall rates of major adverse cardiac events (MACE) and stent thrombosis were similar. The PES group had lower revascularization rates when compared to the SES group. After covariate adjustment, however, there was no difference seen in target vessel revascularization between stent types (hazard ratio [HR]: 2.3 [0.8-6.2], P = 0.110). The strongest predictor of death and MACE at 1 year was the number of diseased vessels.

CONCLUSIONS

Patients with CRI who undergo PCI with either SES or PES have similar repeat revascularization rates and acceptable stent thrombosis rates, although they continue to have high MACE and death rates.

Reliability of prehospital real-time cellular video phone in assessing the simplified National Institutes Of Health Stroke Scale in patients with acute stroke: a novel telemedicine technology

BACKGROUND AND PURPOSE

The National Institutes of Health Stroke Scale (NIHSS) is the gold standard to assess patients with acute stroke. We aimed to examine the feasibility and reliability of prehospital real-time cellular video phone (VP) in performing the NIHSS.

METHODS

Forty physicians prospectively performed a simplified NIHSS (sNIHSS) on a standardized patient remotely using VP with the assistance of a bedside emergency medical technician and later performed a bedside examination. We tested the hypothesis that there is high reliability between these 2 methods. Physicians were timed and sNIHSS scores were recorded. Finally, physicians were asked to rate the VP technology.

RESULTS

A total of 480 pair comparisons of the sNIHSS scores between the VP and bedside examination were generated. After adjusting for the physician's specialty, level of training, and certification status, there was a strong positive linear correlation (r=0.97, P < 0.01) between the 2 methods with high average physician reliability (0.99; 95% CI, 0.992 to 0.995). The mean sNIHSS scores using VP and bedside examination were not different (6.82 ± 1.06 versus 6.63 ± 0.98; P=0.08). The mean time to perform the sNIHSS using VP was approximately 38 seconds longer than the bedside examination (3.38 ± 0.77 versus 2.93 ± 0.83 minutes; P=0.006).

CONCLUSIONS

The VP is a feasible, reliable, and timely tool with the potential for remotely assessing the sNIHSS for patients presenting with acute stroke and may expedite the initial evaluation and treatment strategies.

Effect of insurance type on adverse cardiac events after percutaneous coronary intervention

Previous studies have documented disparities in both access to invasive cardiovascular procedures and outcomes in patients with Medicaid, Medicare, or no insurance. Outcomes by insurance have yet not been examined in a percutaneous coronary intervention (PCI) population. Data from patients undergoing PCI from June 2000 to June 2009 were retrospectively analyzed. Insurance was categorized as private, Medicare, Medicaid, and uninsured, according to the primary insurance at discharge. The outcome variable of interest was major adverse cardiac events (a composite of death, Q-wave myocardial infarction, and target vessel revascularization) at 1 year. Multivariable Cox regression analysis was stratified according to age <65 and ≥65 years. Of the 13,573 patients who had undergone PCI, 6,653 (49.0%) had private insurance, 6,150 (45.3%) had Medicare, 486 (3.6%) had Medicaid, and 284 (2.1%) were uninsured. Of the patients <65 years old, Medicaid (hazard ratio [HR] 1.59, 95% confidence interval [CI] 1.04 to 2.43), Medicare (HR 2.18, 95% CI 1.58 to 2.99), and no insurance (HR 2.41, 95% CI 1.36 to 4.27) were associated with greater rates of adjusted major adverse cardiac events at 1 year compared with private insurance. Of the patients ≥65 years old, only Medicaid (HR 3.07, 95% CI 1.09 to 8.61) was associated with a greater rate of adjusted major adverse cardiac events at 1 year. In conclusion, patients with government-sponsored insurance and no insurance have worse cardiovascular outcomes than patients with private insurance after PCI at 1 year. This implies that the provision of health insurance alone might not have a dramatic effect on cardiovascular outcomes after PCI.

Does on- versus off-hours presentation impact in-hospital outcomes of ST-segment elevation myocardial infarction patients transferred to a tertiary care center?

OBJECTIVES

To determine whether in-hospital outcome differs for transferred patients with ST-segment elevation myocardial infarction (STEMI) presenting during business (ON) hours vs. after (OFF) hours.

BACKGROUND

Door-to-device (DTD) time is a prognostic factor in patients with STEMI and is longer during OFF hours. However, the in-hospital mortality is controversial.

METHODS

This registry study included 786 consecutive patients with STEMI referred for primary percutaneous coronary intervention to a tertiary care center with an on-site cardiac catheterization team 24 hrs a day/7 days (24/7) a week. ON hours were defined as weekdays 8 a.m. to 5 p.m., while OFF hours were defined as all other times, including holidays. The primary outcomes were in-hospital death, reinfarction, and length of stay (LOS).

RESULTS

ON hours (29.5%, n = 232) and OFF hours (70.5%, n = 554) groups had similar demographic and baseline characteristics. A significantly higher proportion of patients presenting ON hours had a DTD time ≤120 min compared to OFF hours patients (32.6% vs. 22.1%, P = 0.007). The rates of in-hospital death (8.2% vs. 6%), reinfarction (0% vs. 1.1%), and mean LOS (5.7 ± 6 vs. 5.7 ± 5) were not significantly different in the ON vs. OFF hours groups, all P = nonsignificant.

CONCLUSION

In a tertiary care center with an on-site cardiac catheterization team 24/7, there are no differences in in-hospital outcomes of transferred patients with STEMI during ON vs. OFF hours.

Correlates and consequences of gastrointestinal bleeding complicating percutaneous coronary intervention

Gastrointestinal bleeding (GIB) complicating percutaneous coronary intervention (PCI) results in high mortality, but clinical factors associated with and long-term outcomes of GIB are poorly understood. We sought to examine clinical and procedural factors associated with GIB complicating PCI. We also examined the impact of GIB on 30-day mortality and 1-year major adverse cardiac events (MACEs). Patients undergoing PCI from January 2000 to January 2010 were retrospectively analyzed for the occurrence of in-hospital GIB. Multivariable logistic regression and Cox proportional hazards regression were used to identify predictors of in-hospital GIB and 30-day mortality. Landmark analysis of patients surviving to hospital discharge was performed to assess the impact of GIB on 1-year MACEs. Of 20,621 patients who underwent PCI, 147 (0.72%) who developed in-hospital GIB were identified. Variables associated with increased risk of GIB included older age, shock, acute myocardial infarction, chronic renal insufficiency, lower baseline hematocrit, and glycoprotein IIb/IIIa inhibitors; bivalirudin decreased the risk. Unadjusted 30-day mortality rate of patients with GIB was 20.5% compared to 2.4% of patients without GIB. After multivariable adjustment, GIB and shock (and an interaction between the 2) were the most important correlates of 30-day mortality. In the population surviving to discharge, however, GIB was not associated with adjusted mortality or MACEs. In conclusion, GIB complicating PCI has a dramatic impact on 30-day mortality, and bivalirudin was associated with lower rates of GIB.