Behavioral effects of exposure to organic solvents in carpet layers.

Carpet layers and age-matched controls were investigated both at the beginning of a working day and at the end with four subtests of a neuropsychological test battery (NES2). Exposure to toluene, cyclohexane, ethyl acetate, and heptane was measured with personal air sampling methods. One group of carpet layers used water-based adhesives (WBA) on the day the investigation took place and the other group used contact adhesives (CA) on that day. The WBA group was exposed primarily to toluene, and the CA group was exposed to other solvents as well. Initial (before work) differences in neuropsychological scores between all exposed workers and controls could be attributed to differences in education, the carpet layers being somewhat higher educated. No differences were found between the solvent-exposed and control groups that would suggest persistent effects of chronic solvent exposures. The improvement in test scores over the day was the same in both groups. However, evidence for exposure-related changes in test scores over the day were found within the exposed group.

Exposure to styrene and health complaints in the Dutch glass-reinforced plastics industry.

A study of the health hazards for workers exposed to styrene in the Dutch glass-reinforced plastics industry was undertaken. The open mould techniques of filament winding, spraying and hand laminating were chosen for study because exposure of workers using them was expected to be high. Occupational hygiene surveys were conducted in four plants. In addition to measurements of exposure, data on health complaints were collected. In 12 smaller plants exposure was estimated in walk-through surveys. The results show that although most of the plants had implemented control measures such as ventilation and extraction, the levels of exposure constituted a health risk. Time-weighted average concentrations for workers involved in filament winding ranged from 134 to 716 mg m-3, for those who were spraying from 48 to 602 mg m-3 and for those laminating manually from 18 to 538 mg m-3. The 'no-adverse-effect level' based on effects observed in man is considered to be 105 mg m-3, and the acute subjective health effects experienced by the population studied supported this value. To reduce exposure to below 105 mg m-3, control measures should combine engineering with codes of practice adapted to the particular process or processes employed.

Tissue plasminogen activator in refractory unstable angina. A randomized double-blind placebo-controlled trial in patients with refractory unstable angina and subsequent angioplasty.

To evaluate the effect of recombinant tissue plasminogen activator (alteplase) on the clinical course, angiographic changes and the outcome of subsequent coronary angioplasty, 36 patients with angina at rest, despite bedrest and medical treatment including heparin, and with concomitant ECG changes, were studied. After diagnostic angiography, patients were randomized to receive either alteplase 100 mg in 3 h (19 patients), or placebo (17 patients). The mean interval between qualifying anginal episode and initial angiography was 10 and 9 h for the alteplase and placebo group, respectively. Angiography was repeated and angioplasty was performed within 24 hours. Between the first and the second angiogram, five patients in the alteplase and seven in the placebo group had recurrent ischaemic episodes, while four alteplase and three placebo patients showed signs of myocardial necrosis (creatine kinase (CK) rise greater than or equal to twice the upper limit for normal). Intracoronary clots were recognized in three alteplase patients and one placebo patient at the first angiogram, while two alteplase patients and one placebo patient showed total occlusion of the ischaemic-related vessel. After infusion, thrombi were present in four alteplase patients and one placebo patient, and total occlusion in three alteplase patients and one placebo patient. Quantitative coronary angiography showed no change in the percentage diameter stenosis of the ischaemia-related segment after drug infusion, (alteplase 67 +/- 16 to 69 +/- 16%; placebo 65 +/- 11 to 63 +/- 12%). Angioplasty was successful in 14 of 19 alteplase and 14 of 16 placebo patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Transesophageal echocardiography in evaluation and management after a Fontan procedure.

Transesophageal echocardiography was used in 18 patients (aged 1.6 to 34 years, mean age 12.6) to assess the immediate (5 patients) or intermediate (13 patients) results after a Fontan-type procedure. The findings were correlated with precordial echocardiographic (all patients) and cardiac catheterization (11 patients) data. Atrial shunting was documented by transesophageal studies in three patients (precordial in one patient). In two patients it was confirmed by cardiac catheterization; the third underwent reoperation based on the transesophageal study alone. Pulmonary artery obstruction was documented in three patients (precordial in one patient) and was confirmed by subsequent cardiac catheterization in all. Evaluation of anterior Fontan connections was successful in 5 of 8 patients (precordial in 6 of 8), and posterior connections in 10 of 10 patients (precordial in 5 of 10). A Glenn shunt could be evaluated in eight of nine patients (precordial in three of nine). Thrombus formation was detected by transesophageal studies in three patients (precordial in one patient); repeat studies were used to evaluate thrombolytic therapy in two. Atrioventricular valvular regurgitation (11 of 18 patients) was better defined by transesophageal than by precordial studies (5 of 18). A coronary artery fistula was identified in two cases (precordial in none). Transesophageal pulsed Doppler interrogation of pulmonary artery and pulmonary vein flow patterns consistently allowed a detailed evaluation of the Fontan circulation. Transesophageal echocardiography is an important diagnostic and monitoring technique after the Fontan procedure. In this series, it was far superior to precordial ultrasound evaluation and of substantial additional value to cardiac catheterization.

The role of transoesophageal echocardiography in adolescents and adults with congenital heart defects.

Between April 1985 and December 1989, outpatient transoesophageal echocardiography was performed in 133 adolescent and adult patients (14% of all outpatient transoesophageal studies) (age range 11-78 years; weight 30-95 kg) to determine the value of this technique both in establishing the primary diagnosis (62 patients) and in the post-surgical follow up (71 patients) of congenital heart disease. The results were correlated with the findings of precordial echocardiography, catheterization and surgical inspection. Clear advantages of transoesophageal imaging over precordial imaging include: (1) direct identification of atrial appendage morphology in all patients; (2) delineation of systemic and pulmonary venous connections; (3) atrial baffle function (eight patients); (4) better evaluation of the Fontan-type circulation (five patients); (5) improved morphologic assessment of the atrioventricular junction and valves (29 patients); (6) definition of subaortic obstruction (18 patients); and (7) definition of ascending aortic morphology in Marfan's syndrome and supravalvar aortic stenosis (13 patients). The problems encountered with transoesophageal imaging include: (1) limited imaging planes; (2) poor visualization of specific intracardiac regions (antero-apical trabecular septum, right ventricular outflow tract); (3) flow masking behind implanted intracardiac prosthetic material.

Comparative values of the precordial and transesophageal approaches in the echocardiographic evaluation of atrial baffle function after an atrial correction procedure.

Previous methods used to assess atrial baffle function after correction of transposition of the great arteries have included precordial echocardiography and cardiac catheterization. To evaluate whether single plane transesophageal echocardiography might provide additional information, its findings were correlated with information derived from both precordial echocardiography and cardiac catheterization in 15 patients (14 Mustard procedures, 1 Senning procedure) aged 4.2 to 33 years (mean 16.3). Precordial ultrasound with combined imaging, color flow mapping and pulsed Doppler ultrasound visualized the supramitral portion of the common systemic venous atrium in every case but could identify only superior limb obstruction in three of six patients, mid-baffle obstruction in zero of two and inferior limb obstruction in zero of two patients. Transesophageal studies with use of the same range of ultrasound methods demonstrated superior limb obstruction (severe in four, mild in two) in six of six patients, mid-baffle obstruction in two of two and inferior limb obstruction in two of two patients. The entire pulmonary venous atrium was equally well interrogated by either ultrasound approach, with both identifying three cases (two mild, one moderate) of mid-pulmonary venous atrium obstruction. However, individual pulmonary vein velocity profiles could only be recorded by transesophageal pulsed Doppler ultrasound. Precordial studies identified baffle leaks (1 large, 2 small) in only three patients, whereas transesophageal studies identified 11 such baffle leaks (1 large, 10 small), which were multiple in two patients. It is concluded that transesophageal echocardiography provides a more detailed and accurate assessment of atrial baffle morphology and function than is provided by either precordial ultrasound or cardiac catheterization.(ABSTRACT TRUNCATED AT 250 WORDS)

Doppler color flow mapping in the diagnosis of ventricular septal rupture and acute mitral regurgitation after myocardial infarction.

Fifty consecutive patients with a newly acquired systolic murmur and severe cardiac decompensation following a recent myocardial infarction (27 with an anterior and 23 with an inferior infarct) were studied by a combination of two-dimensional echocardiography, spectral Doppler and Doppler color flow mapping. The initial ultrasound study defined a ventricular septal rupture in 43 patients and severe isolated mitral regurgitation in 7 patients (5 with papillary muscle rupture and 2 with severe papillary muscle dysfunction). All 50 patients had subsequent confirmation of the diagnosis by either cardiac catheterization or surgical inspection, or both. Two-dimensional echocardiography alone directly visualized a septal defect in only 17 (40%) of the 43 patients with ventricular septal rupture. In all 43 patients the mitral valve appeared normal on imaging. In six of the seven patients with isolated mitral regurgitation, two-dimensional echocardiography correctly demonstrated the structural abnormality of the mitral valve (five with flail anterior leaflet and one with posterior leaflet prolapse). The addition of Doppler color flow mapping greatly improved the diagnostic information in both patient groups. In all 43 patients with ventricular septal rupture, Doppler color flow mapping demonstrated both an area of turbulent transseptal flow and a diagnostic systolic flow disturbance within the right ventricle. In the seven patients with isolated papillary muscle rupture or dysfunction, Doppler color flow mapping not only demonstrated the presence of mitral regurgitation in all cases, but also identified the specific mitral leaflet abnormality by defining the direction of the regurgitant jet.(ABSTRACT TRUNCATED AT 250 WORDS)

Incidence of restenosis after successful coronary angioplasty: a time-related phenomenon. A quantitative angiographic study in 342 consecutive patients at 1, 2, 3, and 4 months.

Data from experimental, clinical, and pathologic studies have suggested that the process of restenosis begins very early after coronary angioplasty. The present study was performed to determine prospectively the incidence of restenosis with use of the four National Heart, Lung, and Blood Institute and the 50% or greater diameter stenosis criteria, as well as a criterion based on a decrease of 0.72 mm or more in minimal luminal diameter. Patients were recatheterized at 30, 60, 90, or 120 days after successful percutaneous transluminal coronary angioplasty (PTCA). After PTCA all patients received 10 mg nifedipine three to six times a day and aspirin once a day until repeat angiography. Of 400 consecutive patients in whom PTCA was successful (less than 50% diameter stenosis), 342 underwent quantitative angiographic follow-up (86%) by use of an automated edge-detection technique. A wide variation in the incidence of restenosis was found dependent on the criterion applied. The incidence of restenosis proved to be progressive to at least the third month for all except NHLBI criterion II. At 4 months a further increase in the incidence of restenosis was observed when defined as a decrease of 0.72 mm or more in minimal luminal diameter, whereas the criteria based on percentage diameter stenosis showed a variable response. The lack of overlap between the different restenosis criteria applied affirms the arbitrary nature of angiographic definitions currently in use. Restenosis should be assessed by repeat angiography, and preferably ascertained according to the change in absolute quantitative measurements of the luminal diameter.

Coronary angioplasty of the unstable angina related vessel in patients with multivessel disease.

This study is a retrospective analysis of the efficacy of percutaneous transluminal coronary angioplasty of the ischaemia-related vessel in patients with unstable angina. Forty-three patients had multivessel disease with dilatation of the ischaemia-related vessel only (group I; partial revascularization) while 111 patients had single vessel disease only (group II; total revascularization). The initial success rate in both groups was identical (88 versus 88%). The need for emergency coronary artery bypass surgery was similar in the two groups (group I 12% versus group II 9%; NS). The total post PTCA myocardial infarction rate (despite urgent CABG) was also similar in the two groups (group I 9% versus group II 10%; NS). The results of electrocardiographic exercise testing and Thallium-201 scintigraphy provide objective evidence for incomplete revascularization in group I. The maximum workload achieved was lower, and the frequency of exercise induced angina, ST-segment depression and reversible perfusion defect was higher than in group II. Moreover, at 6 months follow-up the recurrence rate of angina pectoris rate was higher in group I than in group II (29% versus 16% P less than 0.05). It is concluded that dilatation of the ischaemia related vessel only in patients with unstable angina and multivessel disease is as effective in the management of the acute phase of unstable angina as is dilatation of the ischaemia related vessel in patients with single vessel disease. However, due to only partial revascularization the recurrence rate of angina pectoris is higher.