Akshay Bagai

Do Blood Tests Cause Anemia in Hospitalized Patients?: The Effect of Diagnostic Phlebotomy on Hemoglobin and Hematocrit Levels

OBJECTIVE: To determine whether phlebotomy contributes to changes in hemoglobin and hematocrit levels in hospitalized general internal medicine patients.DESIGN: Retrospective cohort study.SETTING: General internal medicine inpatient service at a tertiary care hospital.PARTICIPANTS: All adult patients discharged from the Toronto General Hospital’s internal medicine service between January 1 and June 30, 2001. A total of 989 hospitalizations were reviewed and 404 hospitalizations were included in our analysis.MEASUREMENTS AND MAIN RESULTS: Mean (SD) hemoglobin and hematocrit changes during hospitalization were 7.9 (12.6) g/L (P<.0001) and 2.1% (3.8%) (P<.0001), respectively. The mean (SD) volume of phlebotomy during hospital stay was 74.6 (52.1) mL. On univariate analysis, changes in hemoglobin and hematocrit were predicted by the volume of phlebotomy, length of hospital stay, admission hemoglobin/hematocrit value, age, Charlson comorbidity index, and admission intravascular volume status. The volume of phlebotomy remained a strong predictor of drop in hemoglobin and hematocrit after adjusting for other predictors using multivariate analysis (P<.0001). On average, every 100mL of phlebotomy was associated with a decrease in hemoglobin and hematocrit of 7.0g/L and 1.9%, respectively.CONCLUSIONS: Phlebotomy is highly associated with changes in hemoglobin and hematocrit levels for patients admitted to an internal medicine service and can contribute to anemia. This anemia, in turn, may have significant consequences, especially for patients with cardiorespiratory diseases. Knowing the expected changes in hemoglobin and hematocrit due to diagnostic phlebotomy will help guide when to investigate anemia in hospitalized patients.

Emergency Department Bypass for ST-Segment–Elevation Myocardial Infarction Patients Identified With a Prehospital Electrocardiogram A Report From the American Heart Association Mission: Lifeline Program

Background— For patients identified before hospital arrival with ST-segment–elevation myocardial infarction, bypassing the emergency department (ED) with direct transport to the catheterization laboratory may shorten reperfusion times. Methods and Results— We studied 12 581 ST-segment–elevation myocardial infarction patients identified with a prehospital ECG treated at 371 primary percutaneous coronary intervention–capable US hospitals participating in the Acute Coronary Treatment and Intervention Outcomes Network Registry–Get With The Guidelines, including those participating in the American Heart Association Mission: Lifeline program from 2008 to 2011. Reperfusion times with primary percutaneous coronary intervention and in-hospital mortality rates were compared between patients undergoing ED evaluation and those bypassing the ED. ED bypass occurred in 1316 patients (10.5%). These patients had a lower frequency of heart failure and shock on presentation and nonsystem reasons for delay in percutaneous coronary intervention. ED bypass occurred more frequently during working hours compared with off-hours (18.3% versus 4.3%); ED bypass rate varied significantly across hospitals (median, 3.3%; range, 0%–71%). First medical contact to device activation time was shorter (median, 68 minutes [interquartile range, 54–85 minutes] versus 88 minutes [interquartile range, 73–106 minutes]; P<0.0001) and achieved within 90 minutes more frequently (80.7% versus 53.7%; P<0.0001) with ED bypass. The unadjusted in-hospital mortality rate was lower among ED bypass patients (2.7% versus 4.1%; P=0.01), but the adjusted mortality risk was similar (adjusted odds ratio, 0.69; 95% confidence interval, 0.45–1.03; P=0.07). Conclusions— Among ST-segment–elevation myocardial infarction patients identified with a prehospital ECG, the rate of ED bypass varied significantly across US hospitals, but ED bypass occurred infrequently and was mostly isolated to working hours. Because ED bypass was associated with shorter reperfusion times and numerically lower mortality rates, further exploration of and advocacy for the implementation of this process appear warranted.

Clinical outcomes after hybrid coronary revascularization versus coronary artery bypass surgery: a meta-analysis of 1,190 patients

BACKGROUND Hybrid coronary revascularization (HCR) represents a minimally invasive revascularization strategy in which the durability of the internal mammary artery to left anterior descending artery graft is combined with percutaneous coronary intervention to treat remaining lesions. We performed a systematic review and meta-analysis to compare clinical outcomes after HCR with conventional coronary artery bypass graft (CABG) surgery. METHODS A comprehensive EMBASE and PUBMED search was performed for comparative studies evaluating in-hospital and 1-year death, myocardial infarction (MI), stroke, and repeat revascularization. RESULTS Six observational studies (1 case control, 5 propensity adjusted) comprising 1,190 patients were included; 366 (30.8%) patients underwent HCR (185 staged and 181 concurrent), and 824 (69.2%) were treated with CABG (786 off-pump, 38 on-pump). Drug-eluting stents were used in 328 (89.6%) patients undergoing HCR. Hybrid coronary revascularization was associated with lower in-hospital need for blood transfusions, shorter length of stay, and faster return to work. No significant differences were found for the composite of death, MI, stroke, or repeat revascularization during hospitalization (odds ratio 0.63, 95% CI 0.25-1.58, P = .33) and at 1-year follow-up (odds ratio 0.49, 95% CI 0.20-1.24, P = .13). Comparisons of individual components showed no difference in all-cause mortality, MI, or stroke, but higher repeat revascularization among patients treated with HCR. CONCLUSIONS Hybrid coronary revascularization is associated with lower morbidity and similar in-hospital and 1-year major adverse cerebrovascular or cardiac events rates, but greater requirement for repeat revascularization compared with CABG. Further exploration of this strategy with adequately powered randomized trials is warranted.

In-hospital switching between adenosine diphosphate receptor inhibitors in patients with acute myocardial infarction treated with percutaneous coronary intervention: Insights into contemporary practice from the TRANSLATE-ACS study:

Aims: While randomized clinical trials have compared clopidogrel with higher potency adenosine diphosphate (ADP) receptor inhibitors among patients with acute myocardial infarction, little is known about the frequency, effectiveness and safety of switching between ADP receptor inhibitors in routine clinical practice. Methods and results: We studied 11,999 myocardial infarction patients treated with percutaneous coronary intervention at 230 hospitals from April 2010 to October 2012 in the TRANSLATE-ACS study. Multivariable Cox regression was used to compare six-month post-discharge risks of major adverse cardiovascular events (MACE: death, myocardial infarction, stroke, or unplanned revascularization) and Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO)-defined bleeding between in-hospital ADP receptor inhibitor switching versus continuation of the initially selected therapy. Among 8715 patients treated initially with clopidogrel, 994 (11.4%) were switched to prasugrel or ticagrelor; switching occurred primarily after percutaneous coronary intervention (60.9%) and at the time of hospital discharge (26.7%). Among 3284 patients treated initially with prasugrel or ticagrelor, 448 (13.6%) were switched to clopidogrel; 48.2% of switches occurred after percutaneous coronary intervention and 48.0% at hospital discharge. Switching to prasugrel or ticagrelor was not associated with increased bleeding when compared with continuation on clopidogrel (2.7% vs. 3.3%, adjusted hazard ratio 0.96, 95% confidence interval 0.64–1.42, p=0.82). Switching from prasugrel or ticagrelor to clopidogrel was not associated with increased MACE (8.9% vs. 7.7%, adjusted hazard ratio 1.06, 95% confidence interval 0.75–1.49, p=0.76) when compared with continuation on the higher potency agent. Conclusions: In-hospital ADP receptor inhibitor switching occurs in more than one in 10 myocardial infarction patients in contemporary practice. In this observational study, ADP receptor inhibitor switching does not appear to be significantly associated with increased hazard of MACE or bleeding.

Temporal Differences in Out-of-Hospital Cardiac Arrest Incidence and Survival

Background— Understanding temporal differences in the incidence and outcomes of out-of-hospital cardiac arrest (OHCA) has important implications for developing preventative strategies and optimizing systems for OHCA care. Methods and Results— We studied 18 588 OHCAs of presumed cardiac origin in patients aged ≥18 years who received resuscitative efforts by emergency medical services (EMS) and were enrolled in the Cardiac Arrest Registry to Enhance Survival (CARES) from October 1, 2005, to December 31, 2010. We evaluated temporal variability in OHCA incidence and survival to hospital discharge. There was significant variability in the frequency of OHCA by hour of the day (P<0.001), day of the week (P<0.001), and month of the year (P<0.001), with the highest incidence occurring during the daytime, from Friday to Monday, in December. Survival to hospital discharge was lowest for OHCA that occurred overnight (from 11:01 PM to 7 AM; 7.1%) versus daytime (7:01 AM to 3 PM; 10.8%) or evening (3:01 PM to 11 PM; 11.3%; P<0.001) and during the winter (8.8%) versus spring (11.1%), summer (11.0%), or fall (10.0%; P<0.001). There was no difference in survival to hospital discharge between OHCAs that occurred on weekends and weekdays (9.5% versus 10.4%, P=0.06). After multivariable adjustment for age, sex, race, witness status, layperson resuscitation, first monitored cardiac rhythm, and emergency medical services response time, compared with daytime and spring, survival to hospital discharge remained lowest for OHCA that occurred overnight (odds ratio, 0.81; 95% confidence interval, 0.70–0.95; P=0.008) and during the winter (odds ratio, 0.81; 95% confidence interval, 0.70–0.94; P=0.006), respectively. Conclusions— There is significant temporal variability in the incidence of and survival after OHCA. The relative contribution of patient pathophysiology, likelihood of the OHCA being observed, and prehospital and hospital-based resuscitative factors deserves further exploration.

Reperfusion Strategies in Acute Coronary Syndromes

The appropriate timing of angiography to facilitate revascularization is essential to optimize outcomes in patents with ST-segment–elevation myocardial infarction and non–ST-segment–elevation acute coronary syndromes. Timely reperfusion of the infarct-related coronary artery in ST-segment–elevation myocardial infarction both with fibrinolysis or percutaneous coronary intervention minimizes myocardial damage, reduces infarct size, and decreases morbidity and mortality. Primary percutaneous coronary intervention is the preferred reperfusion method if it can be performed in a timely manner. Strategies to reduce health system–related delays in reperfusion include regionalization of ST-segment–elevation myocardial infarction care, performing prehospital ECGs, prehospital activation of the catheterization laboratory, bypassing geographically closer nonpercutaneous coronary intervention–capable hospitals, bypassing the percutaneous coronary intervention–capable hospital emergency department, and early and consistent availability of the catheterization laboratory team. With implementation of such strategies, there has been significant improvement in process measures, including door-to-balloon time. However, despite reductions in door-to-balloon times, there has been little change during the past several years in in-hospital mortality, suggesting additional factors including patient-related delays, optimization of tissue-level perfusion, and cardioprotection must be addressed to improve patient outcomes further. Early angiography followed by revascularization when appropriate also reduces rates of death, MI, and recurrent ischemia in patients with non–ST-segment–elevation acute coronary syndromes, with the greatest benefits realized in the highest risk patients. Among patients with non–ST-segment–elevation acute coronary syndromes with multivessel disease, choice of revascularization modality should be made as in stable coronary artery disease, with a goal of complete ischemic revascularization.

In-Hospital Switching Between Clopidogrel and Prasugrel Among Patients With Acute Myocardial Infarction Treated With Percutaneous Coronary Intervention Insights Into Contemporary Practice From the National Cardiovascular Data Registry

Background—Although randomized clinical trials have compared clopidogrel with higher potency ADP receptor inhibitors (ADPris) among patients with myocardial infarction, little is known about the frequency and factors associated with switching between ADPris in clinical practice. Methods and Results—We studied 47 040 patients with myocardial infarction treated with percutaneous coronary intervention, who received either clopidogrel or prasugrel within 24 hours of admission at 361 US hospitals from July 2009 to June 2011 using the merged Acute Coronary Treatment and Intervention Outcomes Network Registry–Get With the Guidelines and CathPCI Registry database. Hierarchical logistic regression modeling was used to determine factors independently associated with in-hospital ADPri switching. Among 40 531 patients treated initially in-hospital with clopidogrel, 2125 (5.2%) were discharged on prasugrel; this frequency steadily increased from 0% to 7% during the study period. Among 6509 patients treated initially in-hospital with prasugrel, 751 (11.5%) were discharged on clopidogrel. The frequency of this switch increased from 6% to 18% during the first 2 quarters of the study period and decreased to 9% by the end. Switching clopidogrel to prasugrel was associated with high-risk angiographic characteristics (thrombotic, long, and bifurcating lesions), reinfarction in-hospital, and private health insurance coverage. Older age, previous cerebrovascular event, in-hospital coronary artery bypass grafting, in-hospital bleeding, and warfarin use at discharge were associated with switching prasugrel to clopidogrel. Conclusions—Clopidogrel and prasugrel are not uncommonly switched in-hospital in patients with myocardial infarction undergoing percutaneous coronary intervention. In contemporary US practice, in addition to risk for bleeding and recurrent ischemic events, medical drug coverage is a major determinant of ADPri selection.

Regional systems of care demonstration project: Mission: Lifeline STEMI Systems Accelerator: Design and methodology

ST-segment elevation myocardial infarction (STEMI) systems of care have been associated with significant improvement in use and timeliness of reperfusion. Consequently, national guidelines recommend that each community should develop a regional STEMI care system. However, significant barriers continue to impede widespread establishment of regional STEMI care systems in the United States. We designed the Regional Systems of Care Demonstration Project: Mission: Lifeline STEMI Systems Accelerator, a national educational outcome research study in collaboration with the American Heart Association, to comprehensively accelerate the implementation of STEMI care systems in 17 major metropolitan regions encompassing >1,500 emergency medical service agencies and 450 hospitals across the United States. The goals of the program are to identify regional gaps, barriers, and inefficiencies in STEMI care and to devise strategies to implement proven recommendations to enhance the quality and consistency of care. The study interventions, facilitated by national faculty with expertise in regional STEMI system organization in partnership with American Heart Association representatives, draw upon specific resources with proven past effectiveness in augmenting regional organization. These include bringing together leading regional health care providers and institutions to establish common commitment to STEMI care improvement, developing consensus-based standardized protocols in accordance with national professional guidelines to address local needs, and collecting and regularly reviewing regional data to identify areas for improvement. Interventions focus on each component of the reperfusion process: the emergency medical service, the emergency department, the catheterization laboratory, and inter-hospital transfer. The impact of regionalization of STEMI care on clinical outcomes will be evaluated.

Does This Patient With Palpitations Have a Cardiac Arrhythmia

CONTEXT Many patients have palpitations and seek advice from general practitioners. Differentiating benign causes from those resulting from clinically significant cardiac arrhythmia can be challenging and the clinical examination may aid in this process. OBJECTIVE To systematically review the accuracy of historical features, physical examination, and cardiac testing for the diagnosis of cardiac arrhythmia in patients with palpitations. Data Source, Study Selection, and DATA EXTRACTION MEDLINE (1950 to August 25, 2009) and EMBASE (1947 to August 2009) searches of English-language articles that compared clinical features and diagnostic tests in patients with palpitations with a reference standard for cardiac arrhythmia. Of the 277 studies identified by the search strategy, 7 studies were used for accuracy analysis and 16 studies for diagnostic yield analysis. Two authors independently reviewed articles for study data and quality and a third author resolved disagreements. DATA SYNTHESIS Most data were obtained from single studies with small sample sizes. A known history of cardiac disease (likelihood ratio [LR], 2.03; 95% confidence interval [CI], 1.33-3.11), having palpitations affected by sleeping (LR, 2.29; 95% CI, 1.33-3.94), or while the patient is at work (LR, 2.17; 95% CI, 1.19-3.96) slightly increase the likelihood of a cardiac arrhythmia. A known history of panic disorder (LR, 0.26; 95% CI, 0.07-1.01) or having palpitations lasting less than 5 minutes (LR, 0.38; 95% CI, 0.22-0.63) makes the diagnosis of cardiac arrhythmia slightly less likely. The presence of a regular rapid-pounding sensation in the neck (LR, 177; 95% CI, 25-1251) or visible neck pulsations (LR, 2.68; 95% CI, 1.25-5.78) in association with palpitations increases the likelihood of a specific type of arrhythmia (atrioventricular nodal reentry tachycardia). The absence of a regular rapid-pounding sensation in the neck makes detecting the same arrhythmia less likely (LR, 0.07; 95% CI, 0.03-0.19). No other features significantly alter the probability of clinically significant arrhythmia. Diagnostic tests for prolonged periods of electrocardiographic monitoring vary in their yield depending on the modality used, duration of monitoring, and occurrence of typical symptoms during monitoring. Loop monitors have the highest diagnostic yield (34%-84%) for identifying an arrhythmia. CONCLUSIONS While the presence of a regular rapid-pounding sensation in the neck or visible neck pulsations associated with palpitations makes the diagnosis of atrioventricular nodal reentry tachycardia likely, the reviewed studies suggest that the clinical examination is not sufficiently accurate to exclude clinically significant arrhythmias in most patients. Thus, prolonged electrocardiographic monitoring with demonstration of symptom-rhythm correlation is required to make the diagnosis of a cardiac arrhythmia for most patients with recurrent palpitations.

Association of neighborhood characteristics with incidence of out-of-hospital cardiac arrest and rates of bystander-initiated CPR: Implications for community-based education intervention

OBJECTIVE A 10-fold regional variation in survival after out-of-hospital cardiac arrest (OHCA) has been reported in the United States, which partly relates to variability in bystander cardiopulmonary resuscitation (CPR) rates. In order for resources to be focused on areas of greatest need, we conducted a geospatial analysis of variation of CPR rates. METHODS Using 2010-2011 data from Durham, Mecklenburg, and Wake counties in North Carolina participating in the Cardiac Arrest Registry to Enhance Survival (CARES) program, we included all patients with OHCA for whom resuscitation was attempted. Geocoded data and logistic regression modeling were used to assess incidence of OHCA and patterns of bystander CPR according to census tracts and factors associated herewith. RESULTS In total, 1466 patients were included (median age, 65 years [interquartile range 25]; 63.4% men). Bystander CPR by a layperson was initiated in 37.9% of these patients. High-incidence OHCA areas were characterized partly by higher population densities and higher percentages of black race as well as lower levels of education and income. Low rates of bystander CPR were associated with population composition (percent black: OR, 3.73; 95% CI, 2.00-6.97 per 1% increment in black patients; percent elderly: 3.25; 1.41-7.48 per 1% increment in elderly patients; percent living in poverty: 1.77, 1.16-2.71 per 1% increase in patients living in poverty). CONCLUSIONS In 3 counties in North Carolina, areas with low rates of bystander CPR can be identified using geospatial data, and education efforts can be targeted to improve recognition of cardiac arrest and to augment bystander CPR rates.