Aiala Barr

Prognostic significance of ST segment shift early after resolution of ST elevation in patients with myocardial infarction treated with thrombolytic therapy: the GUSTO-I ST Segment Monitoring Substudy.

OBJECTIVES We sought to study the relation between recurrent ST segment shift within 6 to 24 h of initial resolution of ST elevation after thrombolytic therapy and 30-day and 1-year mortality. BACKGROUND Rapid and stable resolution of ST segment elevation in relation to thrombolytic therapy in patients with an acute myocardial infarction is an indicator of culprit artery patency. Whether recurrence of ST segment shift during continuous ST monitoring after initial resolution is related to poor prognosis has not been studied. METHODS ST segment monitoring was performed within 30 min after thrombolytic therapy for acute myocardial infarction. The predictive value of a new ST segment shift (assessed as > or = 0.1-mV deviation from the baseline) 6 to 24 h after thrombolytic therapy was studied with respect to 30-day and 1-year mortality. RESULTS Of 734 patients, 243 had a new ST segment shift (33%). The 30-day mortality rate in patients with an ST shift (7.8%) was significantly higher than that in patients without an ST shift (2.25%, p = 0.001), as was the 1-year mortality rate (10.3% vs. 5.7%, respectively, p = 0.025). Multivariable analysis revealed an independent predictive value of ST shift with respect to 30-day mortality (p = 0.008), even after consideration of multiple clinical risk factors in the overall Global Utilization of Streptokinase and TPA for Occluded Coronary Arteries (GUSTO)-I mortality model (p = 0.0001). Moreover, the duration of the ST shift bore a direct relation with 1-year mortality (p = 0.008). CONCLUSIONS Detection of ST segment shift early after thrombolytic therapy for acute myocardial infarction is a simple, noninvasive means of identifying patients at high risk and is superior to other commonly assessed clinical risk factors. Thus, patients with a new ST shift after the first 6 h, but within 24 h, represent a high risk group that may benefit from more aggressive intervention, whereas patients without evidence of an ST shift represent a low risk subgroup.

Low molecular weight heparin decreases rebound ischemia in unstable angina or non-Q-wave myocardial infarction: the Canadian ESSENCE ST segment monitoring substudy

OBJECTIVES The goal of this study was to determine whether enoxaparin was more effective than heparin in reducing recurrent ischemic episodes. BACKGROUND Continuous ST segment monitoring is a simple tool for assessment of ischemia and identifies patients with a worse prognosis. Little is known about the impact of low molecular weight heparin on ST segment shift. METHODS Patients were randomized to receive enoxaparin or heparin (mean 3.4 days). Three-lead ST segment monitoring was performed for the first 48 h (n = 220) and an additional 48 h (n = 174) after intravenous study drug discontinuation (mean 1.9 days later). RESULTS During initial monitoring, ischemia rates were similar among the heparin and enoxaparin groups (27.2% vs. 22.6%, p = 0.44); however, the time to first ischemic episode was earlier among heparin-treated patients (11 +/- 11 vs. 25 +/- 18 min, p = 0.001). After drug discontinuation, ischemic episodes occurred more frequently (44.6% vs. 25.6%, p = 0.009), and the total ischemic duration was greater among heparin patients (18 +/- 39 vs. 5 +/- 12 min/24 h, p = 0.005). Recurrent ischemia occurred more frequently after discontinuation in the heparin (46% vs. 31%, p = 0.043), but not the enoxaparin, group (18.4% vs. 25%, p = 0.33). Regardless of treatment, patients with ischemia were more likely to die or experience (re)infarction at one year (18.4% vs. 8.3%, p = 0.023). CONCLUSIONS ST segment shift occurs frequently in unstable angina/non-Q-wave myocardial infarction despite antithrombotic therapy and is associated with worse one-year prognosis. Enoxaparin is a more effective antithrombotic treatment than unfractionated heparin and leads to greater prevention of rebound ischemia.

B-Vitamin Deficiency in Hospitalized Patients with Heart Failure

The impact of heart failure and its treatment on specific nutrient requirements is unknown. Furthermore, depletion of water-soluble B vitamins that play key roles in the production of cellular energy in patients with heart failure can contribute to depletion of energy reserves observed in the failing heart. A cross-sectional study recently reported that approximately one third of hospitalized patients with heart failure had tissue levels suggestive of thiamin deficiency (vitamin B-1). Riboflavin (vitamin B-2) and pyridoxine (vitamin B-6) are similar to thiamin in that they are water-soluble, subject to renal excretion, have limited tissue storage, and are dependent on intake. Therefore, it was hypothesized that the status of these B vitamins may also be adversely affected by heart failure. As a result, the prevalence of patients at risk of vitamin B-2 (erythrocyte glutathione reductase activity coefficient > or = 1.2) and B-6 deficiency (plasma B-6 < or = 20 nmol/L) was determined in a cross-section of 100 patients hospitalized with heart failure between April 2001 and June 2002 as well as in a group of volunteers without heart failure. Twenty-seven percent of patients with heart failure had biochemical evidence of vitamin B-2 deficiency, while 38% had evidence of B-6 deficiency. These prevalence rates were significantly higher than those observed in the volunteers without heart failure (2% and 19%, respectively; P < or = 0.02). Use of common B-vitamin-containing supplements by patients with heart failure did not significantly reduce deficiency rates in comparison with those who did not use supplements (B-2 P=0.38 or B-6 P=0.18)). Finally, while 80% of patients with heart failure took diuretics, neither the dose nor the duration of furosemide use was related to the presence of either B-2 or B-6 deficiency. Given the physiologic importance of these vitamins, further investigations aimed at determining the effect of heart failure on specific nutrient requirements as well as the safety and efficacy of B-vitamin supplementation are warranted.

Self-Reported Symptoms of Depression and Memory Dysfunction in Survivors of ARDS

BACKGROUND Survivors of ARDS have well documented physical limitations, but psychological effects are less clear. We determined the prevalence of self-reported depression and memory dysfunction in ARDS survivors. METHODS Six to 48 (median 22) months after ICU discharge, we administered instruments assessing depression symptoms (Beck Depression Inventory-II [BDI-II]) and memory dysfunction (Memory Assessment Clinics Self-Rating Scale [MAC-S]) to 82 ARDS patients who were enrolled in a prospective cohort study in four university-affiliated ICUs. RESULTS Sixty-one (74%), 64 (78%), and 61 (74%) patients fully completed the BDI-II, MAC-S (Ability subscale), and MAC-S (Frequency of Occurrence subscale) instruments. Responders (similar to nonresponders) were young (median 42 years, interquartile range [IQR] 35 to 56), with high admission illness severity and organ dysfunction. The median BDI-II score was 12 (IQR 5 to 25). Twenty-five (41%) patients reported moderate-severe depression symptoms and were less likely to return to work than those with minimal-mild symptoms (8/25 [32%] vs 25/36 [69%]; p = 0.005). Median MAC-S (Ability) and MAC-S (Frequency of Occurrence) scores were 76 (IQR 61 to 93) and 91 (IQR 77 to 102), respectively; 8%, 16%, and 20% scored > 2, > 1.5, and > 1 SD(s), respectively, below age-adjusted population norms for each subscale. BDI-II and MAC-S scores were negatively correlated (Spearman coefficient -0.58 and -0.50 for Ability and Frequency of Occurrence subscales, respectively; p < 0.0001). Univariable analyses showed no demographic or illness-severity predictors of BDI-II (including the Cognitive subscale) or MAC-S (both subscales); results were similar when restricted to patients whose primary language was English. CONCLUSIONS ARDS survivors report a high prevalence of depression symptoms and a lower prevalence of memory dysfunction 6 to 48 months after ICU discharge. Depression symptoms may hinder the return to work, or patients may report these symptoms because of inability to re-enter the workforce.

Renal effects of long-term treatment with 5-aminosalicylic acid

BACKGROUND A number of case reports link the use of 5-aminosalicylic acid (5-ASA) to interstitial nephritis in patients with inflammatory bowel disease (IBD). OBJECTIVE To investigate whether the long-term use of 5-ASA has harmful effects on renal function in patients with IBD. METHODS A retrospective analysis of 171 consecutive outpatients with Crohns disease or ulcerative colitis was conducted. Serum creatinine levels and body weight were measured before and after treatment to calculate the creatinine clearance (CrCl) rate. RESULTS In 171 patients (93 women, 78 men), the mean (+/- SD) dose of 5-ASA was 3.65+/-0.85 g/day with a cumulative dose of 11+/-7.7 kg over an interval of 8.4+/-5.9 years. Serum creatinine concentrations increased from 76.8 micromol/L to 88.7 micromol/L (n=171; P<0.0001) and the CrCl rate fell significantly from 104.6 mL/min to 93.1 mL/min (n=81; P<0.0001). There was one case of interstitial nephritis reported. Treatment groups included mesalamine (74.3%), sulfasalazine (15.2%) and combination (sulfalsalazine/mesalamine [10.5%]) with treatment durations of 7.2+/-4.5, 12.3+/-8.7 and 11.2+/-6.7 years, respectively. The duration of treatment was the most important covariate for change in CrCl and when analyzed by treatment group, those treated with sulfasazine had a strong correlation (r=-0.54, P=0.0145), while nonsignificant in the mesalamine group (r=0.06, P=0.7017). The decline in CrCl was negatively correlated with the pretreatment CrCl rate (r=-0.34; P=0.0024) and positively correlated with the mean daily dose of 5-ASA (r=0.32; P=0.0034). CONCLUSION The present study is the first to demonstrate a significant dose- and treatment duration-dependant decline in CrCl. The risks need to be further evaluated because 5-ASA is widely used for long-term maintenance therapy in patients with IBD.

Hypercapnia increases cerebral tissue oxygen tension in anesthetized rats

PurposeTo test the hypotheses that deliberate elevation of PaCO2 increases cerebral tissue oxygen tension (PBrO2) by augmenting PaO2 and regional cerebral blood flow (rCBF).MethodsAnesthetized rats were exposed to increasing levels of inspired oxygen (O2) or carbon dioxide (CO2; 5%, 10% and 15%,n = 6). Mean arterial blood pressure (MAP), PBrO2 and rCBF were measured continuously. Blood gas analysis and hemoglobin concentrations were determined for each change in inspired gas concentration. Data are presented as mean ± standard deviation withP < 0.05 taken to be significant.ResultsThe PBrO2 increased in proportion to arterial oxygenation (PaO2) when the percentage of inspired O2 was increased. Proportional increases in PaCO2(48.7 ± 4.9, 72.3 ± 6.0 and 95.3 ± l5.4mmHg), PaO2(l72.2± 33.1, 19 1.7 ± 42.5 and 216.0 ± 41.8 mmHg), and PBrO2(29.l ± 9.2, 49.4 ± 19.5 and 60.5 ± 23.0 mmHg) were observed when inspired CO2 concentrations were increased from 0% to 5%, 10% and 15%, respectively, while arterial pH decreased (P < 0.05 for each). Exposure to CO2 increased rCBF from 1.04 ± 0.67 to a peak value of 1.49 ± 0.45 (P < 0.05). Following removal of exogenous CO2, arterial blood gas values returned to baseline while rCBF and PBrO2 remained elevated for over 30 min. The hypercapnia induced increase in PBrO2 was threefold higher than that resulting from a comparable increase in PaO2 achieved by increasing the inspired O2 concentration (34.9 ± 14.5 vs 11.4 ± 5.0 mmHg,P < 0.05).ConclusionThese data support the hypothesis that the combined effect of increased CBF PaO2 and reduced pH collectively contribute to augmenting cerebral PBrO2 during hypercapnia.RésuméObjectifTester l’hypothèse voulant que l’élévation délibérée de la PaCO2 augmente la tension en oxygène du tissu cérébral (TO2TC) en haussant la PaO2 et le débit sanguin cérébral régional (DSCr).MéthodeDes rats anesthésiés ont été exposés à des niveaux croissants d’oxygène inspiré (O2) ou de gaz carbonique (CO2; 5 %, 10% et 15 %, n =6). La tension artérielle moyenne (TAM), la TO2TC et le DSCr ont été mesurés en continu. L’analyse des gaz du sang et les concentrations d’hémoglobine ont été déterminées pour chaque changement de concentration des gaz inspirés. Les données comprennent la moyenne ± l’écart type où P < 0,05 est considéré significatif.RésultatsLa TO2TC a augmenté en proportion de l’oxygénation artérielle (PaO2) quand on augmentait le pourcentage de l’O2 inspiré. Des hausses proportionnelles de la PaCO2 (48,7 ± 4,9, 72,3 ± 6,0 et 95,3 ± 15,4 mmHg), de la PaO2(172,2 ±33,1, 191,7 ±42,5 et 2 16,0 ±41,8 mmHg) et de la TO2TC(29,1 ±9,2, 49,4 ± 19,5 et 60,5 ± 23,0 mmHg) ont été observées avec l’augmentation des concentrations de CO2 inspiré de 0 % à 5 %, 10 % et 15 %, respectivement, tandis que le pH s’est abaissé (P < 0,05 pour chacune). Lexposition au CO2 a fait monter la TO2TC de 1,04 ± 0,67 à une valeur maximale de 1,49 ± 0,45 (P < 0,05). Après le retrait du CO2 exogène, les gaz du sang artériel ont retrouvé leurs valeurs de base tandis que le DSCr et la TO2TC sont demeurés élevés pendant plus de 30 min. Lhypercapnie qui a provoqué une hausse de la TO2TC a été trois fois plus élevée que celle qui a provoqué une hausse comparable de la PaO2 réalisée en augmentant la concentration d’O2 inspiré (34,9 ± 14,5 vs 11,4 ± 5,0 mmHg, P < 0,05).ConclusionNos données confirment l’hypothèse voulant que l’effet combiné de l’augmentation du DSC, de la PaO2 et de la réduction du pH contribue à l’augmentation de la TO2TC pendant l’hypercapnie.

Comparison of Primary Coronary Angioplasty Versus Thrombolysis in Patients With ST-Segment Elevation Acute Myocardial Infarction and Grade II and Grade III Myocardial Ischemia on the Enrollment Electrocardiogram

We investigated the impact of primary angioplasty compared with thrombolysis in 894 patients with ST elevation acute myocardial infarction and electrocardiographic grades II and III ischemia on enrollment. Patients were divided into 2 groups based on the enrollment electrocardiogram-grade III: (1) absence of an S wave below the isoelectric baseline in leads that usually have a terminal S configuration (leads V(1) to V(3)), or (2) ST J-point amplitude > or =50% of the R-wave amplitude in all other leads. To be included in the grade III group, grade III criteria in > or =2 adjacent leads were required. Patients with ST elevation but without grade III criteria were classified as having grade II. In-hospital mortality was 3.2% and 6.8% in the grade II (n = 616) and grade III (n = 278) groups, respectively (p = 0.016). In the grade II group, in-hospital mortality was similar in the thrombolysis and angioplasty subgroups (3.2% and 3.3%, p = 0.941). In patients with grade III, in-hospital mortality was 6.4% and 7.3%, respectively (p = 0.762). The odds ratio for the grade III group for death with thrombolysis was 2.06 (95% confidence intervals [CI] 0.82 to 5.19; p = 0.125); the odds ratio for primary angioplasty was 2.30 (95% CI 0.93 to 5.66; p = 0.07). In the thrombolysis group, reinfarction occurred in 3.3% and 6.5% of the grade II and grade III subgroups (p = 0.137). In the angioplasty group, reinfarction occurred in 1.3% and 4.4%, respectively (p = 0.239). Grade III ischemia on admission was associated with higher in-hospital and 30-day mortality and a higher rate of reinfarction. There was no difference in mortality between primary angioplasty and thrombolysis in the grade II and grade III ischemia patients.

Increased cerebral tissue oxygen tension after extensive hemodilution with a hemoglobin-based oxygen carrier.

Transfusion of anemic patients with hemoglobin-based oxygen carriers (HBOCs) may improve cerebral oxygen delivery. Conversely, cerebral vasoconstriction, associated with HBOC transfusion, could limit optimal cerebral tissue oxygenation. We hypothesized that hemodilution with a HBOC would maintain cerebral tissue oxygenation, despite the occurrence of cerebral vasoconstriction. Isoflurane-anesthetized rats (100% oxygen) underwent direct measurement of mean arterial blood pressure (MAP), caudate tissue oxygen tension (PBrO2), and regional cortical cerebral blood flow (rCBF) before and after 50% of the estimated blood volume (30 mL/kg) was exchanged with either an HBOC (hemoglobin raffimer; Hemolink™) or pentastarch (n = 6). Hemodilution with hemoglobin raffimer caused a transient increase in PBrO2 from 24.9 ± 13.3 mm Hg to 32.2 ± 19.1 mm Hg (P < 0.05), a sustained increase in MAP, and no change in rCBF. Arterial blood oxygen content was maintained despite an increase in methemoglobin and reduced oxygen saturation. Hemodilution with pentastarch caused a transient increase in MAP, no change in PBrO2, and a sustained increase in rCBF (P < 0.05), whereas the hemoglobin concentration and oxygen content were significantly reduced. Hemodilution with hemoglobin raffimer augmented PBrO2 and prevented the increase in rCBF observed after similar hemodilution with pentastarch. These data suggest that transfusion with hemoglobin raffimer may help to maintain cerebral oxygenation during severe anemia.

Clinical comparison of 180-degree and 360-degree data collection of technetium 99m sestamibi SPECT for detection of coronary artery disease

BackgroundWith multihead gamma cameras both 180- and 360-degree acquisitions of myocardial perfusion are feasible. However, with 99mTC-labeled sestamibi (99mTC-sestamibi) the optimal clinically relevant demonstration of the superiority of 180- versus 360-degree data acquisition has not been performed.MethodsSeventy-two consecutive patients undergoing 99mTc-sestamibi imaging at rest and stress who had coronary angiography performed within 3 months were enrolled. The results of blinded interpretation of 13 segments per patient for the 180- and 360-degree data were compared for interobserver variability. Sensitivity and specificity of defect localization in the left anterior descending, right coronary, and left circumflex territories for detection of 50% or greater or 70% or greater stenoses by coronary angiography were compared.ResultsThere was significant segmental agreement of the stress perfusion images between observers for 180-degree (Kappa=0.63) and 360-degree data (Kappa=0.58), but the agreement was significantly higher for 180-degree data (p<0.05). Overall sensitivity for the detection of coronary artery disease as a 50% or greater stenosis in 62 patients was 79% with 180-degree acquisition and 77% with 360-degree acquisition. The specificity for absence of coronary artery disease in 10 patients was also similar at 70% and 80%, respectively. There was no overall difference in detection of individual stenoses with a sensitivity of 54% with 180-degree acquisition and 50% with 360-degree acquisition. Specificity was also similar at 78% and 81%, respectively.ConclusionThere is no difference in clinically relevant detection of overall coronary artery disease or individual stenoses using 180- or 360-degree acquisition of 99mTC-sestamibi myocardial perfusion images. However, 180-degree acquisition has superior interobserver reproducibility.

Relation of Direct Assessment of Cardiac Autonomic Function With Metaiodobenzylguanidine Imaging to Heart Rate Variability in Diabetes Mellitus

Myocardial metaiodobenzylguanidine uptake predicts autonomic function in patients with diabetes mellitus and is significantly related to indexes reflecting sympathetic neural modulation of heart rate variability.