G. Susini

Hemofiltration as short-term treatment for refractory congestive heart failure

Hemofiltration has been suggested as a new therapeutic tool in refractory heart failure. In this study, 11 patients with primary or ischemic heart disease in New York Heart Association class IV, in whom there was no response to medical treatment, were subjected to hemofiltration. The pathophysiologic adjustments promoted by subtraction of plasma water were investigated, and guidelines for an appropriate use of this procedure in heart failure are provided. Fluid was removed from plasma at a rate of 500 ml/hour until either normalization of the right atrial pressure (which was increased in all cases) was achieved or the hematocrit exceeded 50 percent. According to these criteria, the duration of treatment ranged from four to six hours and the total amount of fluid removed was 2,000 to 3,000 ml. In each case, hemofiltration promoted relief of dyspnea and of clinical and radiographic evidence of lung congestion and pleural effusion, and substantially reduced the dependent edema and abdominal girth. These effects were paralleled by progressive decrease of the right (-70 percent) and left (-45 percent) ventricular filling pressures and of the pulmonary arterial pressure and arteriolar resistance, without significant variations in heart rate, aortic pressure, cardiac index, and systemic vascular resistance. Changes in the right atrial and wedge pulmonary pressures are interpreted as reflecting a combined effect of a decrease in pressure on the outside of the heart due to fluid reabsorption (from lung interstitial spaces and pericardial, pleural and abdominal cavities) and of intravascular volume subtraction. The arterial partial pressure of oxygen was raised, the partial pressure of carbon dioxide and pH were unchanged, and urinary output was substantially enhanced by the procedure. The study indicates that: hemofiltration may be a short-term treatment for refractory cardiac insufficiency with overhydration; a filtration rate of 500 ml/hour is effective and safe; and the central venous pressure may be a reliable guide to volume subtraction.

Changes in circulating norepinephrine with hemofiltration in advanced congestive heart failure

In congestive heart failure (CHF), hemofiltration is associated with an obvious decrease in circulating norepinephrine. This method was used for investigating the mechanisms whereby plasma norepinephrine is increased in chronic CHF. In 23 cases of advanced CHF, hemofiltration (2,983 +/- 1,228 ml) lowered plasma norepinephrine by 515 +/- 444 pg/ml. This effect was prompt, persisted or became greater in the next 24 hours. It was not associated with significant changes in cardiac output, aortic pressure or systemic vascular resistance. It did not appear to depend on variations in parameters related to the sympathetic activity, such as plasma renin, right atrial, wedge pulmonary artery and renal perfusion pressures, and was independent of duration and amount of hemofiltration. These observations did not support the concept that the norepinephrine decrease was the main consequence of a neural sympathetic inhibition. Hemofiltration increased diuresis by 606 +/- 415 ml; changes were prompt and correlated inversely (r = -0.7; p less than 0.01) with those in plasma norepinephrine. The same unknown mechanism of the increased urinary output might potentiate the norepinephrine removal from the blood by the kidney, or hemofiltration and the augmented diuresis might result in a regression of congestion of lungs and kidneys, leading to an improved extraction of norepinephrine. In CHF, a relation may exist between fluid retention and norepinephrine and in advanced stages, circulating norepinephrine, although strikingly increased, is devoid of important cardiovascular effects. At these stages, plasma norepinephrine is probably unreliable as an index of the sympathetic neural activity.

Percutaneous pericardiocentesis versus subxiphoid pericardiotomy in cardiac tamponade due to postoperative pericardial effusion

In a retrospective study, 42 patients with acute cardiac tamponade due to pericardial effusion were evaluated following cardiac surgery, and the pericardial fluid was drained by one of two alternative methods: two-dimensional echocardiographic-guided pericardiocentesis (2D-echo) or subxiphoid surgical pericardiotomy. During the first period (from 1982 to 1986), one of the two methods was chosen by the treating physicians, whereas in the second period (from 1986 to 1991), 2D-echo-guided pericardiocentesis was the treatment of choice. Percutaneous pericardiocentesis was performed using local anesthesia in 29 patients. A Tuohy needle was inserted at the left xipho-costal junction and, when fluid was obtained, 6 mL of saline solution was injected during 2D-echo contrast monitoring, and a multiple-hole, 6F, 30-cm catheter was inserted by means of a guidewire and positioned into the posterior pericardium, as near as possible to the atrioventricular groove. Complete drainage of pericardial fluid by percutaneous pericardiocentesis was obtained in 26 patients (89%). This procedure also allowed the evacuation of posterior and loculated effusions. Complications included two right ventricular punctures, which were immediately recognized by 2D-echo contrast and produced no serious consequences. Sixteen patients who underwent surgical pericardiotomy had complete evacuation of pericardial fluid without major complications (two of them suffered atrial arrhythmias during the procedure). The average amount of fluid drained, as well as the localization of the effusions, were the same for both groups. 2D-echo-guided pericardiocentesis was found to be a useful, safe, and simple technique. It can be used as an alternative treatment to subxiphoid pericardiotomy for cardiac tamponade due to postoperative pericardial effusions.

Influences of aortic pressure gradient and ventricular septal thickness with systolic coronary flow in aortic valve stenosis

This study evaluates flow patterns of the left anterior descending and circumflex coronary arteries by multiplane transesophageal echocardiography in 25 patients with aortic valve stenosis, and assesses the relation between coronary flow characteristics and anatomic and hemodynamic parameters.

Coronary flow and left ventricular diastolic function in aortic regurgitation

BackgroundAn abnormal coronary perfusion pressure is probably the major determinant of altered myocardial perfusion in aortic regurgitation; ventricular hypertrophy and diastolic function may also be involved. This study was undertaken to investigate the respective roles of these two variables. MethodsUsing multiplane transesophageal echocardiography, we evaluated the coronary Doppler flow velocity in the proximal left anterior descending coronary artery in 15 patients with aortic regurgitation before and immediately after valve replacement. The ratios of diastolic: systolic velocity integral and early: late diastolic velocity integral were correlated against coronary perfusion pressure, pulmonary wedge pressure and Doppler echocardiographic indices of left ventricular diastolic function. Patients were compared with 10 subjects without valvular diseases. ResultsAortic regurgitation was associated with a reduction of the coronary diastolic: systolic velocity integral ratio and increment in the early: late diastolic velocity integral ratio. The latter correlated positively with early: late diastolic ratio of mitral flow velocity, pulmonary wedge pressure and left ventricular mass index. Soon after valve replacement, a decrease in pulmonary wedge pressure and a rise in coronary perfusion pressure were seen. Both the echo-Doppler parameters related to diastolic function and the systodiastolic distribution of coronary flow returned to normal. This indicates that diastolic dysfunction rather than left ventricular mass may be related to a disordered myocardial perfusion. ConclusionsIn aortic regurgitation, a relationship exists between diastolic ventricular function and coronary flow phasic distribution. Valve replacement improves the former and normalizes the latter. Echo-Doppler parameters of diastolic dysfunction identify patients with worse coronary perfusion and might represent an additional criterion in the preoperative evaluation of patients with aortic regurgitation.