20 research outputs found
Changing climate in the Gulf of California
We conducted a four year interdisciplinary collaborative project focused in the Gulf of California, the most important fishing region for Mexico. We reviewed published reports, collected and analyzed physical, chemical and ecological data sets, and developed models for the physical (atmosphere and ocean) and ecological components of this large marine ecosystem, to examine prevalent scientific questions regarding climate variability and change in the region, covering three time scales (ENSO, decadal-tointerdecadal, and long-term trend). We were able to describe how the Gulf of California influences the northward propagation of coastal trapped Kelvin waves associated with El Niño (ENSO) events, and how this signal, together with changes in the atmospheric forcing, results in a ENSO signature inside the Gulf. For the decadal-to-multidecadal scales, we found coherent trends among series, and with the Pacific Decadal Oscillation (PDO). The long-term temperature signal for the Gulf of California shows a warming that occurred in the mid 20th century, approximately a decade before that in the California Current. This signal is coherent with fluctuations in the industrial fisheries catch records (sardine and shrimps). For the recent decades we found no significant sustained long-term trend in any of the time series of physical and ecological variables that we considered. Instead, variability seems to be fully dominated by the interaction of PDO and ENSO. We stress the urgent need for more modeling efforts and the establishment of interdisciplinary (physical and biological) observation platforms for the marine environment in the Gulf of California
Prospective Validation of the Prognostic Usefulness of B-Type Natriuretic Peptide in Asymptomatic Patients With Chronic Severe Aortic Regurgitation
ObjectivesThe purpose of this study was to determine the independent and additive prognostic value of B-type natriuretic peptide (BNP) in patients with severe asymptomatic aortic regurgitation and normal left ventricular function.BackgroundEarly surgery could be advisable in selected patients with chronic severe aortic regurgitation, but there are no uniform criteria to identify candidates who could benefit from this strategy. Assessment of BNP has not been studied for this purpose.MethodsWe prospectively evaluated 294 consecutive patients with severe asymptomatic organic aortic regurgitation and left ventricular ejection fraction above 55%. The first 160 consecutive patients served as the derivation cohort and the next 134 patients served as a validation cohort. The combined endpoint was the occurrence of symptoms of congestive heart failure, left ventricular dysfunction, or death at follow-up.ResultsThe endpoint was reached in 45 patients (28%) of the derivation set and in 35 patients (26%) of the validation cohort. Receiver-operator characteristic curve analysis yielded an optimal cutoff point of 130 pg/ml for BNP that was able to discriminate between patients at higher risk in both cohorts. BNP was the strongest independent predictor by multivariate analysis in the derivation set (odds ratio: 6.9 [95% confidence interval: 2.52 to 17.57], p < 0.0001) and the validation set (odds ratio: 6.7 [95% confidence interval: 2.9 to 16.9], p = 0.0001).ConclusionsAmong patients with severe asymptomatic aortic regurgitation and normal left ventricular function, BNP ≥130 pg/ml categorizes a subgroup of patients at higher risk. Because of its incremental prognostic value, we believe BNP assessment should be used in the routine clinical evaluation of these patients
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Early reperfusion and late clinical outcomes in patients presenting with acute myocardial infarction randomly assigned to primary percutaneous coronary intervention or streptokinase
Primary percutaneous coronary intervention (PCI) has become an alternative to thrombolytic therapy as a reperfusion strategy for ST-elevation acute myocardial infarction (AMI).
The main goal of this study was to determine whether PCI and thrombolytic therapy achieve comparable reperfusion rates, as evidenced by ST-segment resolution. Secondary end points included infarct vessel patency rates before hospital discharge and short- and long-term outcomes. Patients with ischemic chest pain with duration ≤12 hours and no contraindication for thrombolytic therapy were included.
Between October 1993 and August 1995, 58 patients were randomly assigned to streptokinase (SK) and 54 patients to primary PCI. Baseline clinical characteristics and infarct location were well balanced in both groups. Median age (interquartile range) was 68 (58, 75) years, 29% were women, and 78% of the patients met at least one criterion for “not low risk” AMI (anterior location, age >70 years old, previous MI, systolic blood pressure 100 bpm). The median time from symptom onset to random assignment was 217 (139, 335) minutes in the PCI group and 210 (145, 334) minutes in the SK group. Median random assignment to balloon time was 82 (55, 100) minutes, and median random assignment to needle time was 15 (10, 26) minutes (
P < .0001). TIMI grade 3 flow after primary PCI was obtained in 85% of patients. The proportion of patients with ST-segment resolution ≥50% at 120 minutes was 80% in the PCI group and 50% in the SK group (
P = .001). The predischarge angiogram showed the presence of TIMI 3 flow in 96% of patients who received PCI and 65% of patients who received SK (
P < .001). A composite of in-hospital death, reinfarction, severe heart failure, stroke, and major bleeding occurred in 15% of patients who received PCI and 21% of patients who received SK (
P = .4). At 3 years, freedom from the composite end point of AMI, postdischarge revascularization, and death was 61% in the PCI group and 40% in the SK group (
P = .025).
Our study shows that primary PCI, as compared with SK, is associated with more effective ST-segment resolution, higher patency rates in the infarct vessel at 7 days, and more favorable clinical outcomes at 3 years of follow-up