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Biomedical subjects

Y Birnbaum

Publications and source records attributed to Y Birnbaum.

At least 55 records · Page 3Linked to original sources
PubMed1999

Methylenetetrahydrofolate reductase genotypes and early-onset coronary artery disease.

BACKGROUND: Homozygosity for the common (677C-->T) mutation in the methylenetetrahydrofolate reductase (MTHFR) gene is associated with hyperhomocysteinemia, but there is uncertainty as to the association between this mutation and coronary artery disease (CAD). This study examined the association between MTHFR genotypes and age at onset of CAD. METHODS AND RESULTS: Patients (n=169) with documented myocardial infarction or angiographically documented CAD who were aged < or = 55 years at onset of CAD symptoms and DNA samples from control subjects (n=313) were studied. The prevalence of homozygosity among patients with early CAD onset (aged < or = 45 years) was 28%, which was significantly higher than that in patients with later onset (13%) and in control subjects (14%) (odds ratio 2.4, 95% CI 1.24 to 4.69, P=0.006, and odds ratio 2.7, 95% CI 1.15 to 6.42, P=0.01, respectively). Plasma folate was lower in TT homozygotes who had early CAD onset than in those with later onset (P=0.005). Among patients with plasma folate in the lowest quintile (< or = 12.6 nmol/L), 31% were homozygotes, as were 45% of those with low plasma folate and early CAD onset. There was no difference in the prevalence of traditional risk factors among genotypes. The frequency of homozygosity in patients with < or = 1 risk factor was higher than in those with > or = 2 risk factors (30% versus 12%, P<0.05). In multiple regression analysis, TT homozygosity and plasma folate were independently associated with CAD, but the impact of folate was small. CONCLUSIONS: Homozygosity for the 677C-->T mutation of MTHFR is common and is associated with an increased risk of premature CAD in this population.

Age of Onset↗
PubMed1999

Terminal QRS distortion on admission is better than ST-segment measurements in predicting final infarct size and assessing the Potential effect of thrombolytic therapy in anterior wall acute myocardial infarction.

We assessed predicting final infarct size (using predischarge Selvester score) by 3 electrocardiographic variables in 267 patients with first anterior wall acute myocardial infarction (AMI) undergoing (n = 86) or not undergoing (n = 181) thrombolysis. Patients with previous AMI or inverted T waves in leads with ST elevation were excluded. The sum (sigma) of ST elevation, the number of leads with ST elevation, and the initial electrocardiographic pattern were determined on the admission electrocardiogram (absence (QRS-) or presence (QRS+) of distortion of the terminal portion of the QRS in > or =2 leads (J point > or =0.5 of the R-wave amplitude in leads I, aVL, V4 to V6, or presence of ST elevation without S waves in leads V1 to V3). There was no association between sigmaST elevation and final infarct size in patients who did or did not receive thrombolytic therapy. Analysis of covariance showed that the number of leads with ST elevation (F = 19.6), thrombolysis (F = 25.2), and QRS+ initial pattern (F = 19.5) were all associated with final infarct size (p <0.0001 for all). Among patients who did not receive thrombolytic therapy, the average Selvester score was 19.7+/-9.9 for the QRS- patients and 26.1+/-10.4 for the QRS+ patients (p = 0.02). Among patients who received thrombolytic therapy, the average Selvester score was 11.7+/-9.8 for the QRS- patients and 24.2+/-10.1 for the QRS+ patients (p <0.0001). Thrombolysis reduced final Selvester score only in the QRS- group (p <0.00001), but not in the QRS+ group (p = 0.45). It is concluded that (1) final Selvester score in anterior wall AMI can be predicted by the number of leads with ST elevation, the initial electrocardiographic pattern, and thrombolysis, and (2) thrombolysis reduces final Selvester score only in patients with QRS- pattern.

Adult↗
PubMed1999

Electrocardiographic criteria for predicting the culprit artery in inferior wall acute myocardial infarction.

Two patterns of the QRS complex in the lateral lead aVL on the admission electrocardiograms of patients with inferior wall acute myocardial infarction (AMI) were correlated with the culprit artery. S/R wave ratio < or =1/3 with ST depression < or =1 mm was found to be a sensitive and specific marker for left circumflex artery AMI, whereas S/R-wave ratio >1/3 with ST-segment depression >1 mm was suggestive of right coronary artery AMI.

Cineangiography↗
PubMed1999

Correlation of angiographic findings and right (V1 to V3) versus left (V4 to V6) precordial ST-segment depression in inferior wall acute myocardial infarction.

This study assessed whether differences in the underlying mechanisms for various patterns of precordial ST-segment depression with inferior acute myocardial infarction (AMI) are associated with poorer prognoses. We studied 1,155 patients with inferior AMI who underwent thrombolysis in the Global Utilization of Streptokinase and TPA for Occluded arteries (GUSTO-I) angiographic substudy: those without precordial ST depression (n = 412; 35.7%), those with maximum ST depression in leads V1 to V3 (n = 547; 47.4%), and those with maximum ST depression in leads V4 to V6 (n = 196; 17.0%) on admission electrocardiogram. We compared the infarct-related artery, presence of left anterior descending or multivessel coronary artery disease, and left ventricular function among groups. Patients with maximum ST depression in leads V4 to V6 more often had 3-vessel disease (26.0%) than those without precordial ST depression (13.5%) or those with ST depression in leads V1 to V3 (15.7%; p = 0.002), and they had a lower ejection fraction (median 54% vs 60% and 55%, respectively; p <0.001). Patients with maximum ST depression in leads V1 to V3 less often had AMIs due to proximal right coronary artery obstruction (23.9%) than patients without precordial ST depression (35.2%) or those with ST depression in leads V4 to V6 (40.0%; p = 0.001) and had larger AMIs as estimated by peak creatine kinase. Different patterns of precordial ST depression are associated with distinctive coronary anatomy. ST depression in leads V4 to V6, but not V1 to V3, confers a greater likelihood of multivessel coronary artery disease.

Acute Disease↗
PubMed1999

Acute myocardial infarction following sildenafil citrate (Viagra) intake in a nitrate-free patient.

Since its introduction to the market in March 1997, sildenafil acetate (Viagra) has been prescribed to 1.7 million people. Sixteen men who were taking the drug have died, 7 of them during or soon after sexual activity. Most of these data have been derived from the media and not from the scientific literature. There is a general impression that cardiovascular complications of sildenafil occur mainly when the drug is taken concomitantly with nitrates. We describe a 65-year-old man with known coronary artery disease who had an acute myocardial infarction shortly after taking sildenafil and engaging an sexual activity. The patient had not been using nitrates. We suggest that the emotional arousal induced by Viagra, followed by the heavy physical exertion during sexual activity, triggers plaque rupture that leads to acute myocardial infarction.

Aged↗
PubMed1999

Superiority of the combination of blood and agitated saline for routine contrast enhancement.

The purpose of this study was to evaluate the modification of the saline echo contrast method by mixing blood with agitated saline before intravenous injection. In 20 patients, contrast echocardiography was performed with a conventional technique from the apical 4-chamber view. We used 2 techniques: (1) the combination of blood (1 mL) withdrawn from the patients and air-agitated saline agitated, (2) air-agitated. In all patients, the blood combination technique was judged to make a greater contrast, with the agreement of all 3 reviewers. Peak echo intensity of the right ventricular cavity by the blood combination technique was significantly higher than that by agitated saline alone. In conclusion, the use of the combination of blood and agitated saline is superior to agitated saline alone for the opacification of the right atrium and ventricle in routine echocardiography.

Aged↗
PubMed1999

The prognostic implications of negative T waves in the leads with ST segment elevation on admission in acute myocardial infarction.

We assessed the prognostic significance of negative T waves on admission in leads with ST elevation in 2,853 patients with acute myocardial infarction treated with thrombolysis. Patients were classified into 2 groups based on the presence of negative (T-) or positive (T+) T waves in the leads with ST elevation on admission. T+ and T- waves on admission were detected in 2,601 (91%) and 252 (9%) patients, respectively. T- waves were observed in 6.7 and 9.6% of patients admitted </=2 and 2-6 h after onset of infarction, respectively. There was a difference in prognosis between patients admitted </=2 and >2 h after symptom onset. T- patients admitted </=2 h after onset had no hospital mortality (0/52 patients), as compared to a 5.0% mortality rate in T+ patients (36/726 patients; p = 0.19). T- patients treated >2 h after onset suffered higher mortality (20/196 patients; 10.2%) than T+ patients (100/1,836 patients; 5.4%; p = 0.01). Multivariate analysis of the data on patients treated >2 h after onset demonstrated T- waves to be associated with mortality (OR 1.86; 95% CI 1.07-3.25; p = 0.017). T- waves in leads with ST elevation upon admission are associated with adverse prognosis in patients presenting >2 h after symptom onset, whereas in patients presenting </=2 h after first symptoms, T- waves may be associated with better prognosis.

Diagnostic Tests, Routine↗
PubMed1999

Coronary stent deployment without predilation in acute myocardial infarction: a feasible, safe, and effective technique.

Direct percutaneous transcatheter revascularization (PTCR) is becoming an acceptable therapy for acute myocardial infarction (AMI). Stenting in the setting of AMI, once considered contraindicated, is emerging as a suitable option in this situation. Coronary stenting without predilation (SWOP) may potentially shorten the procedure and radiation time, reduce costs, and decrease procedural complications such as coronary dissection and distal embolization. It is expected to cause less vascular injury, with a reduction in the rate of in-stent restenosis. In this preliminary study the authors evaluated the feasibility of the SWOP procedure in 22 selected patients with AMI. Indications for catheter-based myocardial reperfusion were the following: extensive anterior wall MI (68%), inferior wall and right ventricular MI (23%), and inferior wall MI with contraindication for thrombolytic therapy (9%). Patients with cardiogenic shock or with contraindications for aspirin or ticlopidine were excluded. SWOP was successful in 21 attempts (95%), and final procedural success was achieved in all. Proximal or distal dissections were seen in three cases and were treated by additional three stents. Thrombolysis in myocardial infarction (TIMI) flow 3 was restored in all patients. There were no distal embolizations, side branch occlusions, coronary perforations, procedure-related emergency bypass operations, or deaths. It is concluded that in selected patients with AMI, coronary artery stenting without predilation is feasible and safe and does not introduce additional risk to the patients.

Adult↗
PubMed1998

Enhancement of thrombolysis in vivo without skin and soft tissue damage by transcutaneous ultrasound.

Previous studies have shown that transcutaneous ultrasound enhances thrombolysis by streptokinase in animals in vivo; however, skin and soft tissue damage induced by ultrasound energy has been a major limitation. The objective of this study was to examine the efficacy of thrombolysis and damage to skin and soft tissues using a newly designed concentrated ultrasound system with a cooling manifold. Using a rabbit model with iliofemoral arterial thrombotic occlusions, 15 pairs of arteries were randomized to receive ultrasound treatment or no ultrasound treatment. Streptokinase (25,000 unit/kg) was given intravenously. Skin temperature was maintained at 25-33 degrees C when ultrasound energy was applied. The serum level of creatine kinase, lactate dehydrogenase, red blood cell counts, and platelet counts were checked at baseline, after thrombus induction, and after ultrasound treatment. Fifteen of fifteen (100%) iliofemoral arteries were angiographically recanalized after ultrasound treatment. In contrast, only 1/15 (6.7%) contralateral arteries were patent after 1 hour. After the subsequent hour with heparin the patency was 14/15 in the ultrasound treated group and 3/15 in the control group. Histologically, the patent arteries had only minimal focal mural thrombus, whereas the angiographically occluded arteries had occlusive thrombi. There was no histologic evidence of ultrasound induced damage to overlying skin, soft tissues, or arteries. In addition, there was no significant rise of creatine kinase, lactate dehydrogenase, or decrease in red blood cell counts and platelet counts induced by ultrasound. In conclusion, transcutaneous concentrated ultrasound which significantly enhances streptokinase induced thrombolysis in vivo can be delivered without concomitant tissue damage. This simple combination therapy has clinical potential for safely treating patients with arterial or venous thromboses.

Angiography↗
PubMed1998

Noninvasive in vivo clot dissolution without a thrombolytic drug: recanalization of thrombosed iliofemoral arteries by transcutaneous ultrasound combined with intravenous infusion of microbubbles.

BACKGROUND: Previous in vivo studies have shown that microbubbles not only enhance the effectiveness of thrombolytic agents in the presence of ultrasound but may also augment clot dissolution without thrombolytic drugs. METHODS AND RESULTS: The objective of this study was to examine the efficacy of arterial clot disruption by a noninvasive, nonlytic approach with intravenous administration of perfluorocarbon-exposed sonicated dextrose albumin (PESDA) and transcutaneous delivery of ultrasound alone. Pairs of iliofemoral arteries in 10 rabbits were randomized to receive transcutaneous ultrasound treatment or no ultrasound treatment after an acute artery thrombotic occlusion and intravenous PESDA infusion. Five arteries from 3 additional rabbits served as controls (ultrasound alone). All 10 iliofemoral arteries treated with PESDA + ultrasound were recanalized by angiography after ultrasound treatment. None of the 10 contralateral arteries treated with PESDA alone and none of the 5 arteries treated with ultrasound alone were patent after 1 hour. D-Dimer levels did not change after intravenous PESDA + ultrasound-mediated reperfusion. CONCLUSIONS: In vivo arterial clot dissolution can be achieved with intravenous microbubbles and transcutaneous ultrasound delivery alone. This technique has potential for clinical application in patients with acute arterial and venous thrombotic occlusions.

Animals↗
PubMed1998

Echocardiographic detection of Kaposi's sarcoma causing cardiac tamponade in a patient with acquired immunodeficiency syndrome.

Pericardial effusions are common in patients with acquired immunodeficiency syndrome (AIDS). The differential diagnosis is diverse, and in most cases the etiology cannot be established. A cardiac tamponade was diagnosed in a 32-year-old male with AIDS and systemic Kaposi's sarcoma. Transthoracic echocardiography revealed a large pericardial effusion with right atrial collapse and a mobile multilobular mass at the apex protruding into pericardial space. Autopsy showed that this mass was Kaposi's sarcoma confined to the epicardial fat. This is the first case of cardiac Kaposi's sarcoma detected premortem by echocardiography.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Acute anterior wall myocardial infarction entailing ST-segment elevation in lead V1: electrocardiographic and angiographic correlations.

BACKGROUND: The correlation between ST elevation in lead V1 during anterior wall acute myocardial infarction (AMI) and the culprit lesion site in the left anterior descending (LAD) coronary artery is poor. HYPOTHESIS: The study was undertaken to assess the electrocardiographic (ECG) characteristics and angiographic significance of ST-segment elevation in lead V1 during anterior wall acute myocardial infarction (AMI). METHODS: Data from 115 patients with anterior wall AMI, who underwent coronary angiography within 14 days of hospitalization, were studied. The admission 12-lead ECG was examined and the coronary angiogram was evaluated for the nature of the conal branch of the right coronary artery (RCA) and for the culprit lesion site in the left anterior descending (LAD) coronary artery. RESULTS: Mean ST-segment deviation and the frequency of patients with ST-segment elevation > 0.1 mV were significantly lower in lead V1 than in lead V2 (0.136 +/- 0.111 mV vs. 0.421 +/- 0.260 mV, and 37 vs. 96%, for leads V1 and V2, respectively). A small conal branch not reaching the interventricular septum (IVS) was more prevalent among patients with ST-segment elevation > 0.1 mV in lead V1 (67%), whereas a large conal branch was more prevalent in patients with ST-segment deviation (1 mV in that lead (83%, p < 0.001). No relation was found between ST-segment deviation in lead V1 during anterior wall AMI and the culprit lesion site in the LAD. CONCLUSION: ST-segment elevation in lead V1 during first anterior wall AMI was found in one third of the patients, and its magnitude was lower than that in the other precordial leads. ST-segment elevation in lead V1 favors the presence of a small conal branch of the RCA that does not reach the IVS.

Aged↗
PubMed1998

Admission clinical and electrocardiographic characteristics predicting an increased risk for early reinfarction after thrombolytic therapy.

BACKGROUND: This study assessed the ability of clinical and electrocardiographic variables routinely obtained on admission to identify patients with acute myocardial infarction treated with thrombolytic therapy at risk of early reinfarction. METHODS AND RESULTS: The study included 2602 patients who received thrombolytic therapy for acute myocardial infarction. Baseline demographic variables and admission clinical and electrocardiographic variables were compared between patients with and without reinfarction. Multivariable logistic regression technique was used and included recurrent infarction as the dependent variable, and baseline demographic, clinical, and electrocardiographic variables as independent variables. History of hypertension (odds ratio [OR] 1.52, 95% confidence interval [CI] 1.00 to 2.31) and diabetes mellitus (OR 1.59, 95% CI 1.00 to 2.53) were associated with a higher risk, and current smoking was associated with a lower risk (OR [no versus yes] 1.64, 95% CI 1.05 to 2.58) of early hospital reinfarction. Distortion of the terminal portion of the QRS complex (OR 1.86, 95% CI 1.20 to 2.87) and absence of abnormal Q waves on admission (OR 1.54, 95% CI 0.98 to 2.43) were associated with increased risk of early reinfarction. CONCLUSIONS: A simple electrocardiographic sign is a reliable predictor of early reinfarction among patients who receive thrombolytic therapy for acute myocardial infarction.

Aged↗