The American journal of cardiology
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Multicenter Study Comparative Study Clinical Trial Controlled Clinical Trial
Methodologic issues in clinical evaluation of stenosis severity in adults undergoing aortic or mitral balloon valvuloplasty. The NHLBI Balloon Valvuloplasty Registry.
Although both catheterization and Doppler measures of valvular stenosis severity have been validated, each has specific advantages and limitations, particularly in the setting of balloon valvuloplasty. Invasive valve area and mean pressure gradient recorded immediately before and after aortic (n = 589) or mitral (n = 608) catheter balloon valvuloplasty were compared with Doppler valve area and mean pressure gradient recorded less than 30 days before and 24 to 72 hours after the procedure. For aortic stenosis, Doppler valve area ranged from 0.1 to 1.4 cm2 before and 0.2 to 2.3 cm2 after catheter balloon valvuloplasty. ⋯ Important variables affecting the differences were mitral regurgitation, interatrial shunt, cardiac output and heart rate. Nonsimultaneous studies, differing volume flow measurements, and the underlying accuracy of each technique largely account for discrepancies between these methods. The clinical use of each will depend on its ability to predict long-term patient outcome.
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Comparative Study
Immediate and follow-up results of the conservative coronary angioplasty strategy for unstable angina pectoris.
To assess the results of a conservative coronary angioplasty strategy in unstable angina pectoris, the records of 1,421 consecutive patients without previous myocardial infarction undergoing a first percutaneous transluminal coronary angioplasty (PTCA) between 1986 and 1990 were reviewed. Of these patients, 631 had unstable and 790 had stable angina pectoris. Only after an intense effort to medically control symptoms, the unstable patients underwent PTCA at an average of 15.4 days (range 1 to 76) after hospital admission. ⋯ During 6-month follow-up, no significant difference in adverse events was found between the groups. The respective rates for the unstable and stable groups were 0.4 and 0.2% for death, 5.5 and 5.1% for major nonfatal events, and 17.7 and 20.1% for repeat PTCA. These results suggest that use of a conservative PTCA strategy in the treatment of patients with unstable angina pectoris results in favorable and similar immediate and 6-month outcomes compared with those in patients with stable angina pectoris.
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The clinical impact of percutaneous balloon angioplasty on the management of patients with native or postoperative pulmonary arterial stenosis was reviewed. Seventy-four patients underwent 110 angioplasty procedures. Mean age at dilation was 6.7 +/- 5.3 years (range 0.2 to 18.1), 17 patients were aged less than 1 year, mean follow-up was 37.7 +/- 22.8 months (range 16 to 96), and 34 patients (44%) had follow-up angiography. ⋯ No correlation was found between success and cardiac diagnosis (p = 0.48), site of stenosis (p = 0.78), balloon-vessel ratio (p = 0.42), or whether the stenotic area consisted of native or synthetic material (p = 0.22). No predictive factors for success could be defined, and often there was only a transient clinical impact. Due to the low complication risk and potential for a beneficial result, it still appears prudent to offer angioplasty as an initial therapeutic modality in this setting.
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Comparative Study
Validity of cardiac output measurement by computer-averaged impedance cardiography, and comparison with simultaneous thermodilution determinations.
The accuracy and reproducibility of noninvasive cardiac output determinations by computer-averaged impedance cardiography were compared with those of simultaneously performed thermodilution cardiac output. In all, 43 patients (14 men and 29 women = 201 pairs) were studied by simultaneously performed impedance and thermal determinations. Individual impedance values correlated with paired thermodilution determinations (r = 0.75; p less than 0.0001). ⋯ Mean impedance output was 4.5 +/- 1.27 liter/min Reproducibility was comparable for impedance (0.0059 +/- 0.639) and thermodilution cardiac output (0.023 +/- 0.556). There was high agreement between methods by plot of the difference against mean of the 2 methods. Impedance cardiac output values agree and correlate highly with quality-controlled thermodilution outputs across a wide range of clinical conditions and hemodynamic values.