Circulation
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Two alternative anesthetic techniques for use during carotid endarterectomy were studied in a series of 424 procedures. A total of 248 were performed in patients under general anesthesia and 176 patients received regional block anesthesia. Perioperative instability of blood pressure was noted in 108 patients. ⋯ The 1 month operative mortality for the entire carotid series was 1.2% (5/424). There were three stroke-related deaths. In addition, two nonfatal major strokes and two minor strokes occurred in patients who received general anesthesia vs one nonfatal major stroke in a patient who received regional block anesthesia.
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Reconstructive surgery of the mitral valve has been an alternative to mitral valve replacement in patients with mitral regurgitation. Previously, we reported on postoperative left ventricular outflow tract obstruction associated with systolic anterior motion of the anterior mitral leaflet. The current study was designed to evaluate the incidence of this complication and the long-term results of mitral valve reconstructive surgery. ⋯ An additional patient who had systolic anterior motion but no gradient developed a 36 mm Hg gradient after inhalation of amyl nitrite. The remaining patients had no gradient induced by amyl nitrite. Abnormal systolic anterior motion of the anterior mitral leaflet may be surgically induced by changes in left ventricular geometry and the size of the left ventricular outflow tract during systole.(ABSTRACT TRUNCATED AT 250 WORDS)
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Total left ventricular external power and aortic input impedance spectra were calculated from recordings of pulsatile pressure and flow in the ascending aorta of 22 human subjects undergoing cardiac catheterization. Eleven subjects had increased aortic pressure (systolic 153 +/- 3.8[SEM] mm Hg, p less than .001; diastolic 91 +/- 2.4 mm Hg, p less than .03; mean 118 +/- 2.4 mm Hg, p less than .001) and constituted the group with mild hypertension (average age 50 +/- 1.9 years). The other 11 (age-matched) subjects had normal arterial pressures and constituted the control group. ⋯ These elevated pulsatile components of arterial load were associated with a significant (p less than .002) increase in pulsatile left ventricular external power (89%), and the increased cardiac output was associated with a significant (p less than .001) increase in steady flow power (31%). The ratio of pulsatile to total power was also increased (38%) in the hypertensive group (p less than .001). Increased characteristic aortic impedance in the hypertensive group suggests that the human aorta is stiffer, and fluctuations in the impedance spectra suggest increased or less dispersed wave reflections.(ABSTRACT TRUNCATED AT 250 WORDS)
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We evaluated the ability of Doppler echocardiography to assess left ventricular performance in six open-chest dogs studied under various conditions. Intravenous infusions of nitroglycerin were used to vary preload, atrial pacing was used to control heart rate, and changes in inotropic state were induced by two different doses of dobutamine (5 and 10 micrograms/kg/min iv) and by administration of propranolol (1 mg/kg iv). Left ventricular anterior wall myocardial segment length was used as an index of preload. ⋯ Within a given animal, Doppler measurements of peak velocity correlated very closely with maximum aortic flow (r = .96), maximum acceleration of aortic flow (r = .95), and with maximum dP/dt (r = .92). Mean acceleration measured by Doppler echocardiography also correlated very closely with conventional indexes, but was subject to greater interobserver variability. Doppler measurements of time to peak and the systolic velocity integral correlated less well with conventional hemodynamic indexes.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Clinical Trial
A prospective evaluation of the Björk-Shiley, Hancock, and Carpentier-Edwards heart valve prostheses.
From 1975 to 1979, 540 patients undergoing valve replacement were entered into a randomized trial and received either a Björk-Shiley (273 patients) or a porcine heterograft prosthesis (initially a Hancock valve [107 patients] and later a Carpentier-Edwards prosthesis [160 patients]). Two hundred and sixty-two patients required mitral valve replacement, 210 required aortic valve replacement, 60 required mitral and aortic valve replacement, and eight also required associated tricuspid valve replacement (six mitral valve replacement; two mitral plus aortic valve replacement). Analysis of 34 preoperative and operative variables showed the treatment groups to be well randomized. ⋯ There were too few patients undergoing mitral plus aortic valve replacement for meaningful comparison. There was no significant beneficial effect of anticoagulants in patients undergoing mitral or aortic valve replacement with porcine prostheses, but patients were not randomly allocated to anticoagulant treatment. All patients with Björk-Shiley prostheses received anticoagulants.(ABSTRACT TRUNCATED AT 400 WORDS)