A comparison of percutaneous coronary intervention and surgical revascularization after fibrinolysis for acute myocardial infarction. Insights from the InTIME-2 trial

BACKGROUND

A substantial proportion of patients treated with fibrinolytics for acute myocardial infarction (AMI) is subsequently submitted to surgical or percutaneous revascularization procedures during the same hospitalization. However, data comparing these procedures are scarce in the literature. The purpose of this study was to analyze the outcomes of a population with AMI who, during the in-hospital phase, received fibrinolytic therapy followed by coronary artery bypass graft (CABG) or percutaneous coronary intervention (PCI).

METHODS

The study population included 3532 patients submitted to CABG (N=574) or PCI (N=2958), out of 15,114 patients studied in the InTIME-2 trial. Among patients treated with PCI there were no differences between those who received stents or isolated balloon angioplasty, so that their data were pooled for analysis.

RESULTS

CABG and PCI groups were compared regarding all-cause mortality (at 30 days and one year post-AMI) and non-fatal events (reinfarction, need of additional post-discharge revascularization and re-hospitalization for an ischemic event) within 30 days after MI. There was no significant difference in mortality rates between the groups--both unadjusted and adjusted--at 30 days and one year post-MI. The unadjusted 30-day rates of combined fatal and non-fatal events were 10.3% for the CABG group, and 15.3% for the PCI group (odds-ratio 0.64, P=0.0017), but the adjusted odds-ratio for the combined endpoint only achieved borderline significance (P=0.048).

CONCLUSION

Mortality rates for CABG and PCI were similar up to one year after AMI, but CABG tends to carry a better event-free survival in the first 30 days.

Minor segmental wall motion abnormalities detected in patients with Chagas' disease have adverse prognostic implications

Recent data from our laboratory have shown that patients with the indeterminate form of Chagas' disease can have impairment of left ventricular contractility, as evaluated by the slope of the left ventricle end-systolic pressure-dimension relationship. We also showed that Chagas' disease patients with minimal baseline wall motion abnormalities detected by two-dimensional echocardiography have more intense contractility impairment when compared to patients with the indeterminate form of the disease without this abnormality. The prognostic implications of these findings have not been established. We evaluated 59 patients (37-76 years, mean = 55 years) with different clinical forms of Chagas' disease, who had normal left ventricular global systolic function at baseline (57.6 +/- 6.9%) and who had at least one additional echo during clinical follow-up (0.4-17.6; mean 4.6 years). Group 1 consisted of 14 patients with minor baseline left ventricle wall motion abnormalities and group 2 consisted of 45 patients without these abnormalities. During follow-up, global left ventricle systolic function deterioration was observed in 10 group 1 patients (71.4%) and in only 10 group 2 patients (22.2%; P < 0.005). Age and duration of follow-up were not independent determinants of left ventricular function deterioration in these patients. The present data indicate that mild segmental left ventricular wall motion abnormalities are associated with worsening of systolic function in Chagas' disease patients who have normal baseline global systolic performance.

Automated grading of left ventricular segmental wall motion by an artificial neural network using color kinesis images

The present study describes an auxiliary tool in the diagnosis of left ventricular (LV) segmental wall motion (WM) abnormalities based on color-coded echocardiographic WM images. An artificial neural network (ANN) was developed and validated for grading LV segmental WM using data from color kinesis (CK) images, a technique developed to display the timing and magnitude of global and regional WM in real time. We evaluated 21 normal subjects and 20 patients with LVWM abnormalities revealed by two-dimensional echocardiography. CK images were obtained in two sets of viewing planes. A method was developed to analyze CK images, providing quantitation of fractional area change in each of the 16 LV segments. Two experienced observers analyzed LVWM from two-dimensional images and scored them as: 1) normal, 2) mild hypokinesia, 3) moderate hypokinesia, 4) severe hypokinesia, 5) akinesia, and 6) dyskinesia. Based on expert analysis of 10 normal subjects and 10 patients, we trained a multilayer perceptron ANN using a back-propagation algorithm to provide automated grading of LVWM, and this ANN was then tested in the remaining subjects. Excellent concordance between expert and ANN analysis was shown by ROC curve analysis, with measured area under the curve of 0.975. An excellent correlation was also obtained for global LV segmental WM index by expert and ANN analysis (R2 = 0.99). In conclusion, ANN showed high accuracy for automated semi-quantitative grading of WM based on CK images. This technique can be an important aid, improving diagnostic accuracy and reducing inter-observer variability in scoring segmental LVWM.

Mortality and morbidity remain high despite captopril and/or Valsartan therapy in elderly patients with left ventricular systolic dysfunction, heart failure, or both after acute myocardial infarction: results from the Valsartan in Acute Myocardial Infarction Trial (VALIANT)

BACKGROUND

The elderly constitute an increasing proportion of acute myocardial infarction patients and have disproportionately high mortality and morbidity. Those with heart failure or impaired left ventricular left ventricular function after acute myocardial infarction have high complication and mortality rates. Little is known about outcomes with contemporary therapies in these patients.

METHODS AND RESULTS

The Valsartan in Acute Myocardial Infarction Trial (VALIANT) randomized 14,703 patients with heart failure and/or left ventricular ejection fraction <40% to receive captopril, valsartan, or both. Mortality and a composite end point, including cardiovascular mortality, readmission for heart failure, reinfarction, stroke, and resuscitated cardiac arrest, were compared for the age groups of <65 (n=6988), 65 to 74 (n=4555), 75 to 84 (n=2777), and > or =85 (n=383) years. With increasing age, 3-year mortality almost quadrupled (13.4%, 26.3%, 36.0%, and 52.1%, respectively), composite end-point events more than doubled (25.2%, 41.0%, 52.3%, and 66.8%), and hospital admissions for heart failure almost tripled (12.0%, 23.1%, 31.3%, and 35.4%). Outcomes did not differ between the 3 study treatments in any age group. Adverse events associated with captopril and valsartan were more common in the elderly and in patients receiving combination therapy. With increasing age, use of aspirin, beta-blockers, and statins declined, and use of digoxin, calcium-channel blockers, and non-potassium-sparing diuretics increased. On 3-year multivariable analysis, each 10-year age increase was associated with a hazard ratio of 1.49 (95% CI, 1.426 to 1.557; P<0.0001) for mortality and an odds ratio of 1.38 (95% CI, 1.31 to 1.46; P<0.0001) for readmission with heart failure.

CONCLUSIONS

Outcomes remained poor in elderly patients with heart failure and/or impaired left ventricular systolic function after acute myocardial infarction, although most received beta-blockers and all received an ACE inhibitor and/or an angiotensin receptor blocker. Better therapies and increased use of aspirin, beta-blockers, and statins are needed in this important and increasing patient group.

[Post-extrasystolic potentiation in chronic Chagas' heart disease. A radiologic contrast ventriculography study]

OBJECTIVE

To determine the existence and frequency of the phenomenon of post-extrasystolic potentiation in dyssynergic myocardial areas of patients with chronic Chagas' heart disease studied by use of radiologic contrast ventriculography.

METHODS

This study is a semiquantitative retrospective analysis of radiologic contrast ventriculography in patients with chronic Chagas' disease, who were consecutively studied to assess the mechanisms of ventricular tachycardia.

RESULTS

Of the 72 patients initially included, in only 20 patients was possible the ventriculographic analysis for the purposes of this study. The phenomenon of post-extrasystolic potentiation was observed in 11 (55%) of these patients, and a 15.31% improvement was observed in the contractility score from the baseline to the post-extrasystole condition (P=0.0001). That phenomenon occurred even in ventricular segments with an intense deficit in contractility.

CONCLUSION

The phenomenon of post-extrasystolic potentiation is observed in a significant proportion of patients with chronic Chagas' heart disease, in whom the phenomenon could be angiographically analyzed, indicating the existence of potentially recruitable contractile reserve in ventricular regions, showing marked dyssynergy. Additional studies for clarifying the underlying mechanisms are required.

Ultrasonic tissue characterization for patients with Chagas' disease

This study was undertaken to test the hypothesis that ultrasonic tissue characterization, as evaluated by intensity and cardiac cyclic variation of integrated backscatter (IBS), could identify early myocardial involvement in Chagas' disease. We evaluated 69 participants, age 15 to 73 years (mean +/- SD: 49 +/- 12 years), who were divided as following: 19 control subjects; 13 patients with the indeterminate form of Chagas' disease; 7 patients with the digestive form; and 30 patients with the cardiac form. IBS images were obtained in parasternal short-axis (basal, papillary muscle, apical) view and analyzed in 12 left ventricular (LV) segments (anterior, lateral, posterior, and septal). The following IBS variables were evaluated: (1) the corrected coefficient (CC) of IBS, obtained by dividing IBS intensity, in each cardiac segment, by IBS intensity measured in a rubber phantom using the same equipment adjustments at the same depth; and (2) magnitude of cardiac cyclic variation (MCV) of IBS, as measured by the peak-to-peak difference between maximal and minimal values of IBS in cardiac cycle. The CC of IBS was increased (P <.05) for patients with the cardiac form who had LV segments with normal wall motion as compared with control subjects, in 4 of 12 segments evaluated (basal anterior, midposterior and midseptal, anterior apical), whereas the remaining chagasic groups were comparable with controls subjects. The CC of IBS tended to increase with worsening of LV segmental wall motion. MCV showed a large individual variability and had a large mean value (P <.05) in just 1 of 12 segments evaluated, when patients with the cardiac form were compared with control subjects. No correlation was observed between the magnitude of LV dysfunction and MCV of IBS.

IN CONCLUSION

(1) the CC of IBS was able to provide early differentiation of cardiac involvement for patients with Chagas' disease who had LV segments with normal wall motion; (2) increase of CC of IBS with worsening of LV segmental wall motion suggests a relationship between the acoustic properties of myocardial tissue and grading of myocardial fibrosis; (3) MCV was not able to differentiate patients with Chagas' disease from control subjects; and (4) patients with the indeterminate form of Chagas' disease were not differentiated from control subjects by any of the IBS techniques evaluated in this study.

The X-X-/E+E+ genotype of the XbaI/EcoRI polymorphisms of the apolipoprotein B gene as a marker of coronary artery disease in a Brazilian sample

Studies that consider polymorphisms within the apolipoprotein B (apo B) gene as risk factors for coronary artery disease (CAD) have reported conflicting results. The aim of the present study was to search for associations between two DNA RFLPs (XbaI and EcoRI) of the apo B gene and CAD diagnosed by angiography. In the present study we compared 116 Brazilian patients (92 men) with CAD (CAD+) to 78 control patients (26 men) without ischemia or arterial damage (CAD-). The allele frequencies at the XbaI (X) and EcoRI (E) sites did not differ between groups. The genotype distributions of CAD+ and CAD- patients were different (chi (1) = 6.27, P = 0.012) when assigned to two classes (X-X-/E+E+ and the remaining XbaI/EcoRI genotypes). Multivariate logistic regression analysis showed that individuals with the X-X-/E+E+ genotype presented a 6.1 higher chance of developing CAD than individuals with the other XbaI/EcoRI genotypes, independently of the other risk factors considered (sex, tobacco consumption, total cholesterol, hypertension, and triglycerides). We conclude that the X-X-/E+E genotype may be in linkage disequilibrium with an unknown variation in the apo B gene or with a variation in another gene that affects the risk of CAD.

Functional pulmonary atresia in a newborn with normal intracardiac anatomy

Functional pulmonary atresia is a relatively rare clinical condition usually associated with Ebstein's malformation, tricuspid valve dysplasia, Uhl's anomaly, or transient myocardial ischemia with severe tricuspid regurgitation. The occurrence of functional pulmonary atresia associated with transient tricuspid regurgitation in a newborn with an anatomically normal heart is even more uncommon. We describe a case in which color Doppler flow mapping played an essential role in diagnosis and follow-up of this clinical condition in a newborn who had normal intracardiac anatomy.

Minor segmental dyssynergy reflects extensive myocardial damage and global left ventricle dysfunction in chronic Chagas disease

The majority of patients with Chagas disease (ChD) remain for 10 to 30 years or even for life in the indeterminate form (IF) of this disease. They have positive-specific serology tests for ChD, but no symptoms or physical signs, and normal findings for electrocardiograms (ECGs) and heart, esophagus, and colon radiographs. To investigate whether patients in this phase of disease have any impairment of left ventricular (LV) systolic performance, we assessed their contractility index by the slope of the LV end-systolic pressure-dimension (P(es)-D(es)) relation. We studied 35 patients with ChD (14 IF, 11 digestive form [DF], 10 cardiac form [CF]) and 13 healthy subjects. Patients with the CF had only minor cardiac involvement (bundle-branch block, normal LV ejection fraction). All patients had normal baseline global LV systolic function on 2-dimensional echocardiography, but minor segmental wall motion abnormalities were observed in 3 DF, 3 IF, and 2 CF patients. At rest and during intravenous phenylephrine infusion, we measured LV dimensions by echocardiography, and LV end-systolic pressure was estimated by a calibrated carotid pulse tracing. We also measured percent fractional shortening (%DeltaD) and the rate-corrected mean velocity of fiber shortening (Vcf(c)). Mean values (+/- SD) of %DeltaD and Vcf(c) were not significantly different from those exhibited by healthy control subjects in any of the ChD groups at rest (except for CF) or at peak stress using phenylephrine. The P(es)-D(es) slope was similarly and significantly reduced in all ChD patients (IF: 50.7 +/- 25; DF: 52.3 +/- 24; CF: 60.8 +/- 22 mm Hg/cm) compared with normal subjects (89 +/- 17 mm Hg/cm). The P(es)-D(es) slope was even more depressed (39.6 +/- 10 mm Hg/cm) in ChD patients who had minor segmental wall motion abnormalities (SWMAs) on the baseline 2-dimensional echocardiograph in comparison with the slightly reduced values found in patients with CF who had isolated conduction abnormalities on the ECG (71.8 +/- 10 mm Hg/cm). Although %DeltaD and Vcf(c), even at peak afterload, do not differentiate ChD patients from normal controls, the P(es)-D(es) slope is significantly impaired in IF, DF, and CF patients. The remarkably lower P(es)-D(es) slope value documented in ChD patients exhibiting only minor LVWMAs suggests a more extensive myocardial damage in this group of patients, indicating that they should be considered as exhibiting symptoms of the CF version of the disease.

Effects of aerobic exercise training on heart rate variability during wakefulness and sleep and cardiorespiratory responses of young and middle-aged healthy men

The purpose of the present study was to evaluate the effects of aerobic physical training (APT) on heart rate variability (HRV) and cardiorespiratory responses at peak condition and ventilatory anaerobic threshold. Ten young (Y: median = 21 years) and seven middle-aged (MA = 53 years) healthy sedentary men were studied. Dynamic exercise tests were performed on a cycloergometer using a continuous ramp protocol (12 to 20 W/min) until exhaustion. A dynamic 24-h electrocardiogram was analyzed by time (TD) (standard deviation of mean R-R intervals) and frequency domain (FD) methods. The power spectral components were expressed as absolute (a) and normalized units (nu) at low (LF) and high (HF) frequencies and as the LF/HF ratio. Control (C) condition: HRV in TD (Y: 108, MA: 96 ms; P<0.05) and FD - LFa, HFa - was significantly higher in young (1030; 2589 ms2/Hz) than in middle-aged men (357; 342 ms2/Hz) only during sleep (P<0.05); post-training effects: resting bradycardia (P<0.05) in the awake condition in both groups; VO2 increased for both groups at anaerobic threshold (P<0.05), and at peak condition only in young men; HRV in TD and FD (a and nu) was not significantly changed by training in either groups. The vagal predominance during sleep is reduced with aging. The resting bradycardia induced by short-term APT in both age groups suggests that this adaptation is much more related to intrinsic alterations in sinus node than in efferent vagal-sympathetic modulation. Furthermore, the greater alterations in VO2 than in HRV may be related to short-term APT.

Prediction of left ventricular wall motion recovery after acute myocardial infarction by Tl-201 gated SPECT: incremental value of integrated contractile reserve assessment

BACKGROUND

This investigation tested the application of low-dose dobutamine (LDD) gated single photon emission computed tomography (SPECT) with thallium 201 for myocardial viability detection early after acute myocardial infarction (AMI).

METHODS AND RESULTS

Thirty-two hemodynamically stable post-AMI patients (aged 55 +/- 5 years [mean +/- SEM]; 20 men) who were exhibiting regional left ventricular dysfunction underwent stress-redistribution Tl-201 scanning within 4 to 8 days, followed by 2 additional gated SPECT acquisitions after Tl-201 reinjection, at rest and during LDD. A visual 5-point score was computed for segmental radiotracer uptake (0, normal; 4, absent) and a 4-point score for left ventricular wall motion (1, normal; 4, dyskinesis). Predominant viable myocardium in dyssynergic regions was predicted by a mean Tl-201 uptake score of 2 or less or ischemic area of 30% or greater. These indices showed a significant association with wall motion improvement in follow-up echocardiographic studies (overall accuracy = 0.69, sensitivity = 0.93, and specificity = 0.50). Regarding the response to LDD stimulus, an increase in mean wall motion score of 30% or greater was predictive of predominant viable myocardium. Contractile reserve assessment yielded a significant increment in the predictive accuracy for function recovery (overall accuracy = 0.84, sensitivity = 0.71, and specificity = 0.94).

CONCLUSIONS

Evaluation of contractile reserve by means of LDD gated SPECT with Tl-201 is safely feasible early after AMI, with incremental value over perfusion assessment alone for myocardial viability detection.

Trypanocidal drugs for chronic asymptomatic Trypanosoma cruzi infection

BACKGROUND

Prior guidelines stated that trypanocidal therapy should not be used for treating chronic asymptomatic Trypanosoma cruzi infections. However, the recent availability of clinical trials reporting high rates of parasitologic cure in children with early chronic T. cruzi infection have produced changes of these recommendations in some countries. Because of the uncertainty regarding best treatment for this stage of T. cruzi infections, the literature was reviewed systematically for a synthesis of the available evidence.

OBJECTIVES

To assess the effects of trypanocidal therapy for chronic asymptomatic T. cruzi infection.

SEARCH STRATEGY

We searched The Cochrane Controlled Trials Register (Issue 1, 2000), MEDLINE (start-Nov 1999), EMBASE (start - Feb 2000), LILACS (start - Feb 2000) and the Tropical Diseases Research Division of WHO database (Start - Feb 2000). Reference lists of articles were searched for relevant material.

SELECTION CRITERIA

Published RCTs of trypanocidal therapy for people with chronic, asymptomatic T. cruzi infections

DATA COLLECTION AND ANALYSIS

Two reviewers independently screened papers for inclusion criteria, quality assessment and data extraction. Forms were used to collect data. Reviewers resolved differences by discussion then a third reviewer if necessary.

MAIN RESULTS

Of 43 papers assessed for inclusion, five RCTs (total population=756) met the inclusion criteria. The quality of the trials was rated as low (n=3) or intermediate (n=2). Two RCTs tested benznidazole in school children and three tested different agents in adults. The Odds Ratios and their 95%CI (Fixed models) were: Incidence of ECG abnormalities: 0.41 (0.09, 1.85); Negative seroconversion (AT ELISA): 10.91 (6.07, 19.58); Negative xenodiagnosis during the follow up: 5.37 (3.34, 8.64); Standardised mean reduction of antibody titres: 0.54 (0.31, 0.84). Nitroimidazolic derivatives substantially and significantly modified parasite-related outcomes compared to placebo. Other agents showed borderline or not significant effect.

REVIEWER'S CONCLUSIONS

Despite major public health importance, trypanocidal.therapy for chronic asymptomatic T. cruzi infection has been tested in few, small size RCTs which were designed to assess parasitic-related, but not clinical outcomes. Therefore, the potential of trypanocidal therapy to prevent Chagas' disease among asymptomatic, chronically infected subjects is promising, but remains to be evaluated. trypanocidal therapy, particularly nitroimidazolic derivatives given to children or adults with positive xenodiagnosis improve parasite-related outcomes. The large contrast between the burden of Chagas disease and the existing evidence on its prevention points the need to test these or newer agents in more and larger RCTs that include clinical endpoints.

Is left ventricular diastolic thickening documented during dobutamine and pacing stress echocardiography related to myocardial ischemia? An animal model study

Transient increase in diastolic wall thickness (pseudohypertrophy) during pacing stress echocardiography has been reported in normal myocardium. To evaluate the occurrence of pseudohypertrophy and to investigate the contribution of myocardial ischemia on its production during pacing and dobutamine stress echocardiography, we produced a physiologically significant coronary stenosis in 14 open chest dogs. The stenosis in the circumflex artery was measured by quantitative coronary angiography (range: 50% to 89% reduction in luminal diameter), and no resting segmental wall-motion abnormalities were observed by epicardial echocardiography (short-axis, papillary level). In each study, dobutamine (5-40 microg/kg/min) and pacing (up to 260 beats/min) were performed randomly. Positivity of stress echocardiography tests was quantitatively determined by a significant (P < 0.05) reduction or failure to increase in absolute and percent systolic wall thickening in the myocardial area supplied by the stenotic artery as compared to the left anterior descending (LAD) artery-related areas. Diastolic wall thickness and left ventricular diastolic area were compared before and after each stress test in the circumflex and LAD artery-related regions. Pseudohypertrophy was observed in 57% and 86% of dogs for pacing and dobutamine, respectively, in the circumflex region, and in 50% and 64% in the LAD region. Despite its increased incidence in the circumflex region, the augmented diastolic wall thickness did not correlate with coronary stenosis severity or stress test positivity, but correlated inversely with changes in left ventricular diastolic area. In addition, it correlated directly with changes in heart rate only for pacing. In conclusion, pseudohypertrophy was a frequent finding during pacing and dobutamine stress echocardiography tests but was not related to myocardial ischemia in this animal model.

Head-to-head comparison of dipyridamole, dobutamine and pacing stress echocardiography for the detection of myocardial ischemia in an animal model of coronary artery stenosis

To compare the sensitivity of dipyridamole, dobutamine and pacing stress echocardiography for the detection of myocardial ischemia we produced a physiologically significant stenosis in the left circumflex artery of 14 open-chest dogs (range: 50 to 89% reduction in luminal diameter). In each study, dobutamine (5 to 40 microg kg(-1) min(-1) in 3-min stages) and pacing (20 bpm increments, each 2 min, up to 260 bpm) were performed randomly, and then followed by dipyridamole (up to 0.84 mg/kg over 10 min). The positivity of stress echocardiography tests was quantitatively determined by a significant (P<0.05) reduction of or failure to increase absolute and percent systolic wall thickening in the stenotic artery supplied wall, as compared to the opposite wall (areas related to the left anterior descending artery). Systolic and diastolic frozen images were analyzed off-line by two blinded observers in the control and stress conditions. The results showed that 1) the sensitivity of dobutamine, dipyridamole and pacing stress tests was 57, 57 and 36%, respectively; 2) in animals with positive tests, the mean percent change of wall thickening in left ventricular ischemic segments was larger in the pacing (-19 +/- 11%) and dipyridamole (-18 +/- 16%) tests as compared to dobutamine (-9 +/- 6%) (P = 0.05), but a similar mean reduction of wall thickening was observed when this variable was normalized to a control left ventricular segment (area related to the left anterior descending artery) (pacing: -16 +/- 7%; dipyridamole: -25 +/- 16%; dobutamine: -26 +/- 10%; not significant), and 3) a significant correlation was observed between magnitude of coronary stenosis and left ventricular segmental dysfunction induced by ischemia in dogs submitted to positive stress tests. We conclude that the dobutamine and dipyridamole stress tests showed identical sensitivities for the detection of myocardial ischemia in this one-vessel disease animal model with a wide range of left circumflex artery stenosis. The pacing stress test was less sensitive, but the difference was not statistically significant. The magnitude of segmental left ventricular dysfunction induced by ischemia was similar in all stress tests evaluated.

Effects of blood viscosity on proximal flow convergence calculations of regurgitant flow rate and jet dimensions as evaluated by color Doppler flow mapping: an in vitro study

There are limited data on the potential influence of blood viscosity on the quantification of valvular regurgitation by color Doppler in the clinical setting. This study was designed to evaluate the effects of blood viscosity on jet dimensions and the proximal flow convergence (proximal isovelocity surface area, PISA) method of estimating valvular insufficiency severity. We used an in vitro flow model filled with human blood at varying hematocrits (15%, 35%, and 55%) and blood viscosity (blood/water viscosity: 2.6, 4.8, 9.1) in which jets were driven through a known orifice (16 mm(2)) into a 110-mL compliant receiving chamber (compliance: 2.2 mL/mm Hg) by a power injection pump. Blood injections (2 and 4 mL) at flow rates of 4, 6, 8, 10, and 12 mL/s were performed. Proximal flow convergence and spatial distribution of jets were imaged by a 3.5-MHz transducer. Pressure and volume in the flow model were kept constant before each injection. Ultrasound settings were the same for all experiments. Jet area decreased significantly with increasing blood viscosity, but the difference in jet dimensions was much larger for lower than for higher flow rates and for highest blood viscosity. Estimation of flow rate by the PISA method was not significantly influenced by blood viscosity. Blood viscosity has a major influence in jet area, especially for lower flow rates, but did not change significantly the grading of regurgitation by the PISA method. Thus this factor should be considered for determining the method of choice when quantification of valvular regurgitation is performed in patients with anemia or polycythemia.

Gene polymorphisms in the TNF locus and the risk of myocardial infarction

We investigated two genetic polymorphisms in the tumor necrosis factor locus (TNF-alpha -308 G-->A and LT-alpha +252 A-->G) as risk factors for coronary atherothrombotic disease (CAD) by determining its prevalence in 148 survivors of myocardial infarction (MI) with angiographically-proven severe CAD, and in 148 age-, gender- and race-matched controls. The odds ratio (OR) for MI related to the mutant TNF-alpha and LT-alpha alleles was 0.8 (CI95: 0.4-1.3) and 1. 3 (CI95: 0.8-2.0), respectively. We also sought interaction of smoking and metabolic risk factors for MI with each mutant genotype. Smokers not carrying the LT-alpha +252 A-->G mutation had a risk of MI of 2.7 (CI95: 1.4-5.4) whereas in smoking carriers the risk was 6. 9 (CI95: 3.4-14.1). An interactive effect of the LT-alpha mutation may also exist with dyslipidemia (OR for MI in non-carriers was 12 [CI95: 3.2-41.3] and in carriers the OR was 39, [CI95: 5.1-301] and with obesity (OR for MI was 2.7, [CI95: 1-7.2] in non-carriers and in carriers the OR was 6 [CI95: 2.1-16.8]). Lastly, the OR for MI in obese non-carriers of TNF-alpha -308 G-->A was 2.8 (CI95: 1.3-6) and in obese carriers the OR was 14.5 (CI95: 1.8-113). Although significant interactive effects could not be detected, the findings suggest that interaction of polymorphisms in the TNF locus with major risk factors for CAD may exist, and should be explored in larger studies.