Biomedical subjects
Publications and source records attributed to Eric R Bates.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
BACKGROUND: It has been suggested that the survival benefit associated with primary percutaneous coronary intervention (PPCI) in ST-segment elevation myocardial infarction may be attenuated if door-to-balloon (DB) time is delayed by >1 hour beyond door-to-needle (DN) times for fibrinolytic therapy. Whereas DB times are rapid in randomized trials, they are often prolonged in routine practice. We hypothesized that in clinical practice, longer DB-DN times would be associated with higher mortality rates and reduced PPCI survival advantage. We also hypothesized that in addition to PPCI delays, patient risk factors would significantly modulate the relative survival advantage of PPCI over fibrinolysis. METHODS AND RESULTS: DB-DN times were calculated by subtracting median DN time from median DB time at a hospital using data from 192,509 patients at 645 National Registry of Myocardial Infarction hospitals. Hierarchical models that adjusted simultaneously for both patient-level risk factors and hospital-level covariates were used to evaluate the relationship between PCI-related delay, patient risk factors, and in-hospital mortality. Longer DB-DN times were associated with increased mortality (P<0.0001). The DB-DN time at which mortality rates with PPCI were no better than that of fibrinolysis varied considerably depending on patient age, symptom duration, and infarct location. CONCLUSIONS: As DB-DN times increase, the mortality advantage of PPCI over fibrinolysis declines, and this advantage varies considerably depending on patient characteristics. As indicated in the American College of Cardiology/American Heart Association guidelines, both the hospital-based PPCI-related delay (DB-DN time) and patient characteristics should be considered when a reperfusion strategy is selected.
Explore the source record for details and available documents.
BACKGROUND: The success of prehospital triage protocols for patients with ST-elevation myocardial infarction (STEMI) will depend, in part, on how patients are geographically distributed around hospitals that perform percutaneous coronary intervention (PCI). Accordingly, we determined the proportion of the adult population in the United States with timely access to PCI hospitals using driving times and distances. METHODS AND RESULTS: We performed a cross-sectional study using hospital-level data from the American Hospital Association Annual Survey and Census tract-level data on adults 18 years of age or older from the 2000 United States Census. Our aims were to determine the proportion of the adult population who (1) lived within 60 minutes of a PCI hospital and (2) had additional transport times within 30 minutes if directly referred to a PCI hospital as opposed to a closer, non-PCI hospital. Median times and distances to the closest PCI hospital were 11.3 (interquartile range [IQR] 5.7 to 28.5) minutes and 7.9 (IQR 3.5 to 22.4) miles, respectively. A total of 79.0% of the adult population lived within 60 minutes of a PCI hospital. Among those with a non-PCI hospital as their closest facility, 74.0% required additional transport times of <30 minutes if directly referred to a PCI hospital as opposed to the non-PCI hospital. These estimates varied substantially across regions and urban, suburban, and rural Census tracts. CONCLUSIONS: Nearly 80% of the adult population in the United States lived within 60 minutes of a PCI hospital in 2000. Even among those living closer to non-PCI hospitals, almost three fourths would experience <30 minutes of additional delay with direct referral to a PCI hospital, which suggests that such a strategy might be feasible for these individuals.
BACKGROUND: We conducted a randomized, controlled trial of circumferential pulmonary-vein ablation for the treatment of chronic atrial fibrillation. METHODS: A total of 146 patients with a mean (+/-SD) age of 57+/-9 years who had chronic atrial fibrillation were randomly assigned to receive amiodarone and undergo two cardioversions during the first three months alone (the control group) or in combination with circumferential pulmonary-vein ablation. Cardiac rhythm was assessed with daily telephonic transmissions for one year. The left atrial diameter and the severity of symptoms were assessed at 12 months. RESULTS: Among the 77 patients assigned to undergo circumferential pulmonary-vein ablation, ablation was repeated because of recurrent atrial fibrillation in 26 percent of patients and atypical atrial flutter in 6 percent. An intention-to-treat analysis showed that 74 percent of patients in the ablation group and 58 percent of those in the control group were free of recurrent atrial fibrillation or flutter without antiarrhythmic-drug therapy at one year (P=0.05). Among the 69 patients in the control group, 53 (77 percent) crossed over to undergo circumferential pulmonary-vein ablation for recurrent atrial fibrillation by one year and only 3 (4 percent) were in sinus rhythm without antiarrhythmic-drug therapy or ablation. There were significant decreases in the left atrial diameter (12+/-11 percent, P<0.001) and the symptom severity score (59+/-21 percent, P<0.001) among patients who remained in sinus rhythm after circumferential pulmonary-vein ablation. Except for atypical atrial flutter, there were no complications attributable to circumferential pulmonary-vein ablation. CONCLUSIONS: Sinus rhythm can be maintained long term in the majority of patients with chronic atrial fibrillation by means of circumferential pulmonary-vein ablation independently of the effects of antiarrhythmic-drug therapy, cardioversion, or both. The maintenance of sinus rhythm is associated with a significant decrease in both the severity of symptoms and the left atrial diameter.
BACKGROUND: Hospitals with primary percutaneous coronary intervention (PPCI) capability may choose to predominately offer PPCI to their patients with ST-segment elevation myocardial infarction (STEMI), or they may selectively offer PPCI or fibrinolytic therapy based on patient and hospital-level factors. Whether a greater level of hospital specialization with PPCI is associated with better quality of care is unknown. METHODS AND RESULTS: We analyzed data from the National Registry of Myocardial Infarction-4 to compare in-hospital mortality and times to treatment in STEMI across different levels of hospital specialization with PPCI. We divided 463 hospitals into quartiles of PPCI specialization based on the relative proportion of reperfusion-treated patients who underwent PPCI (< or =34.0%, >34.0 to 62.5%, >62.5 to 88.5%, >88.5%). Hierarchical multivariable regression assessed whether PPCI specialization was associated with better outcomes, after adjusting for patient and hospital characteristics, including PPCI volume. We found that greater PPCI specialization was associated with a lower relative risk of in-hospital mortality in patients treated with PPCI (adjusted relative risk comparing the highest and lowest quartiles, 0.64; P=0.006) but not in those treated with fibrinolytic therapy. Compared with patients at hospitals in the lowest quartile of PPCI specialization, adjusted door-to-balloon times in the highest quartile were significantly shorter (99.6 versus 118.3 minutes; P<0.001), and the likelihood of door-to-balloon times exceeding 90 minutes was significantly lower (relative risk, 0.78; P<0.001). Adjusting for PPCI specialization diminished the association between PPCI volume and clinical outcomes. CONCLUSIONS: Greater specialization with PPCI is associated with lower in-hospital mortality and shorter door-to-balloon times in STEMI patients treated with PPCI.
OBJECTIVE: We sought to determine the hemodynamic significance of intermediate RAS by measuring translesional systolic pressure gradients (TSPG), using a pressure-sensing guidewire at baseline and after acetylcholine (ACh) induced hyperemia, following selective renal artery angiography. BACKGROUND: Renal artery stenosis (RAS) is a cause of reversible hypertension and nephropathy. Stenting effectively relieves RAS, however improvement in blood pressure control or renal function is variable and unpredictable. Hemodynamic significance is usually present with RAS when diameter stenosis is >75%, but is less predictable in intermediate (30%-75%) RAS. METHODS: Twenty-two patients (26 renal arteries) with uncontrolled hypertension underwent invasive hemodynamic assessment because of intermediate RAS, defined as radiocontrast angiographic diameter stenosis (DS) between 30% and 75% (quantitative DS was measured prospectively). Translesional pressure gradients were measured using a 0.014" pressure-sensing wire. Hyperemia was induced by administration of intrarenal ACh. RESULTS: Visual and measured angiographic lesion severity did not correlate with TSPG either at baseline (visual DS, R(2) = 0.091, P = 0.13; measured DS, R(2) = 0.124, P = 0.07) or with hyperemia (visual DS, R(2) = 0.057, P = 0.24; measured DS, R(2) = 0.101, P = 0.12). Baseline and maximal hyperemic gradient did correlate (R(2) = 0.567; P < 0.05). Pharmacological provocation produced a significant increase in TSPG (mean; baseline, 18 +/- 21 vs. hyperemia, 34 +/- 41 mm Hg; P < 0.05). A hemodynamically significant lesion (TSPG > 20 mm Hg) was found in 14/26 (54%) arteries (13 patients); 13 (60%) patients subsequently underwent renal artery stenting for hemodynamically significant RAS. At follow-up (at least 30 days), there was a significant decrease in systolic blood pressure (mean; 167 +/- 24 vs. 134 +/- 19 mm Hg; P < 0.001). CONCLUSIONS: Intrarenal administration of ACh induces hyperemia and can be used to unmask resistive renal artery lesions. Gradient measurement and induced hyperemia may be warranted in the invasive assessment of intermediate renal artery stenoses, rather than relying on stenosis severity alone. Further study is needed to determine whether translesional pressure gradients and pharmacological provocation predict clinical benefit after renal artery stenting.
Many cardiovascular experts have called for the creation of specialized myocardial infarction centers and networks in the United States analogous to the current model for major trauma. Patients suffering ST-elevation myocardial infarction (STEMI) and trauma share an essential feature that makes the argument for regionalization persuasive: rapid triage and treatment by highly trained personnel improve survival in both conditions. Despite this similarity, however, the trauma system may be limited as a model for regionalizing STEMI care. First, the development of trauma systems has been hindered by the struggle for sufficient and stable funding, competing interests among individual stakeholders, and the overall lack of desire for state-sponsored healthcare planning in the United States. These same obstacles would need to be overcome if STEMI care is regionalized. Second, unique characteristics related to STEMI care, such as its varied clinical presentation and more lucrative reimbursement, will create new challenges. In this article, we briefly review the current status of trauma systems in the United States and describe why the regionalization of STEMI care may require different methods of healthcare organization.
BACKGROUND: Early revascularization (ERV) in patients with ST-elevation myocardial infarction (STEMI) and cardiogenic shock (CS) reduces mortality rates. Patients admitted to hospitals without revascularization capability have high mortality rates and are not often transferred for ERV. METHODS: Transfer and direct-admit patients with STEMI from the SHOCK Trial and Registry with left ventricular failure (N = 969) were analyzed to determine benefit of ERV in transfer patients. RESULTS: Transfer patients (46%) were younger and less likely to have prior hypertension, myocardial infarction, and heart failure. They received more aggressive treatment, were revascularized later after CS (median 7.3 vs 3.9 hours, P = .0002), and had similar adjusted inhospital mortality compared with direct-admit patients (55% vs 56%). Inhospital mortality was lower in ERV than no/late revascularization (41% vs 53%, P = .017 for transfer patients; 55% vs 71%, P = .0003 for direct-admit patients). Multiple logistic regression showed that inhospital mortality was associated with age (odds ratio [OR] 1.50 per decade increase, 95% CI 1.31-1.73, P < .0001), mean arterial pressure (OR 0.98 per 1 mm Hg increase, 95% CI 0.97-0.99, P < .0001), fibrinolysis before CS (OR 0.65, 95% CI 0.52-0.96, P = .040), and ERV (OR 0.70, 95% CI 0.52-0.96, P = .028), but not transfer admission (OR 1.23, 95% CI 0.86-1.74, P = .26). CONCLUSIONS: Despite longer time to treatment, transfer patients are a selected population with similar adjusted inhospital mortality and ERV benefit as direct-admit patients. Selected patients with STEMI and CS admitted to hospitals without revascularization capability should be transferred to centers with revascularization capability for immediate angiography.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
AIMS: To evaluate the relationship between activated partial thromboplastin time (aPTT) and clinical outcomes in the Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO-V) trial comparing standard-dose reteplase to half-dose reteplase and abciximab. METHODS AND RESULTS: We analysed data on 11,420 patients receiving unfractionated heparin. Peak aPTT levels recorded during the hospitalization were correlated with clinical outcomes. Multivariable logistic regression models examined the relationship between peak aPTT levels and (i) moderate-to-severe bleeding, (ii) intracerebral haemorrhage, (iii) reinfarction, and (iv) 30-day mortality. Non-linear relationships were explored in the models using cubic spline functions. Higher rates of significant complications were seen in both groups when aPTT levels were <50 s or when levels were >70 s. In the combination therapy group, the relationship between aPTT levels and bleeding appeared accentuated. Reinfarction rates increased gradually as aPTT levels were >70 s in both groups, but the relationships were not statistically significant. Peak aPTT levels <50 s were associated with increased 30-day mortality even after multivariable adjustment. CONCLUSION: Peak aPTT levels <50 s and >70 s are associated with worse clinical outcomes in the modern era of fibrinolytic therapy; these relationships are different in patients receiving standard reteplase vs. combination therapy.
BACKGROUND: Treatment delays in patients with ST-segment-elevation myocardial infarction (STEMI) transferred for primary percutaneous coronary intervention (PCI) may decrease the advantage of this strategy over on-site fibrinolytic therapy that has been demonstrated in recent clinical trials. Accordingly, we sought to describe patterns of times to treatment in patients undergoing interhospital transfer for primary PCI in the United States. METHODS AND RESULTS: We analyzed patients with STEMI undergoing interhospital transfer for primary PCI between January 1999 and December 2002 in the National Registry of Myocardial Infarction. The primary outcome was "total" door-to-balloon time measured from time of arrival at the initial hospital to time of balloon inflation at the PCI hospital. Multivariable hierarchical models were used to assess the relationship of total door-to-balloon time with patient and hospital characteristics. Among 4278 patients transferred for primary PCI at 419 hospitals, the median total door-to-balloon time was 180 minutes, with only 4.2% of patients treated within 90 minutes, the benchmark recommended by national quality guidelines. Comorbid conditions, absence of chest pain, delayed presentation after symptom onset, less specific ECG findings, and hospital presentation during off-hours were associated with longer total door-to-balloon times. Patients at teaching hospitals in rural areas also had significantly longer times to treatment. CONCLUSIONS: Total door-to-balloon times for transfer patients undergoing primary PCI in the United States rarely achieve guideline-recommended benchmarks, and current decision making should take these times into account. For the full benefits of primary PCI to be realized in transfer patients, improved systems are urgently needed to minimize total door-to-balloon times.
BACKGROUND: We studied the potential interaction between baseline risk of death and treatment with either standard fibrinolytic monotherapy or combination fibrin and platelet lysis with respect to outcome of patients with ST-elevation myocardial infarction (STEMI) enrolled in the Global Utilization of Strategies To open Occluded arteries (GUSTO) V trial. METHODS: Using the Thrombolysis in Myocardial Infarction (TIMI) risk score (0-14 points) for STEMI, we analyzed the 30-day and 1-year mortality according to treatment assignment and risk category. Multivariable analysis was performed to identify the potential interactions between treatment and baseline risk. RESULTS: The TIMI risk score could be calculated in 16256 patients (98% of patients enrolled). The median score was 2 (1-4) in each treatment group (P = .07). The risk score was significantly associated with 30-day mortality (hazard ratio [HR], 1.52; 95% CI 1.47-1.56, P < .001, for each additional 1 point), as well as with 1-year mortality (HR 1.51, CI 1.47-1.55, P < .001). The treatment allocation was not significantly related to mortality, and there was no significant interaction between baseline risk score and treatment with respect to either end point. Although combination therapy significantly reduced death or reinfarction at 7 days (HR 0.69, CI 0.54-0.89, P < .01), independent of the risk score, there was no significant statistical interaction between the two (P = .29). CONCLUSION: The TIMI risk score accurately predicted early and 1-year mortality in patients with STEMI treated with pharmacological reperfusion. We did not identify any heterogeneity in the response of patients to combination therapy according to their TIMI risk score.
PURPOSE: Clinical trials evaluating acetylcysteine for the prevention of contrast-related nephropathy have reported mixed results. Although previous meta-analyses have concluded that acetylcysteine is beneficial, the recent availability of additional trials calls for reassessment of current evidence. METHODS: We performed a computerized search to identify relevant published and unpublished randomized clinical trials that evaluated acetylcysteine for the prevention of contrast-related nephropathy. Abstracted data from each trial included assessments of clinical outcomes, trial quality, and additional characteristics. The primary outcome of interest was the incidence of nephropathy after contrast administration. Data were combined using random-effects models with the performance of standard tests to assess for heterogeneity and publication bias. Subgroup analyses were also performed. RESULTS: Twenty trials involving 2195 patients met our inclusion criteria. Trials varied in patient demographic characteristics, inclusion criteria, dosing regimens, and trial quality. The summary risk ratio for contrast-related nephropathy was 0.73 (95% confidence interval: 0.52 to 1.0; P = 0.08), a nonsignificant trend towards benefit in patients treated with acetylcysteine. This effect varied, however, across the 20 trials (test of heterogeneity, P = 0.04). Although higher-quality trials demonstrated a stronger benefit for acetylcysteine in general, few reported important elements of study design, such as concealment of allocation, placebo-controls, or double-blinding. Heterogeneity was unexplained by subgroup analyses. CONCLUSION: Acetylcysteine may reduce the incidence of contrast-related nephropathy, but this finding is reported inconsistently across currently available trials. High-quality, large clinical trials are needed before acetylcysteine use in this indication can be recommended universally.
The mortality benefit associated with primary percutaneous coronary intervention (PCI) in ST-segment elevation myocardial infarction may be lost if door-to-balloon time is delayed by >1 hour compared with tissue plasminogen activator therapy door-to-needle time. When a substantial delay in initiating primary PCI is likely, reperfusion therapy with second- or third-generation fibrinolytic agents should be strongly considered.