Gilles Lepage

Aortocoronary Bypass Graft Initial Blood Flow through the Graft, and Early Postoperative Patency

Intraoperative measurements of blood flow were made in 70 patients in whom a total of 103 venous bypass grafts had been inserted from the aorta to the right, the left anterior descending, or the circumflex coronary artery. Cineangiographic evaluation of graft patency was performed in all patients. Overall patency rate was 90.3%. Flow in all bypass grafts averaged 68 ml/min. All grafts with flow of 20 ml or less or which failed to respond to the injection of 20 mg of papaverine became occluded. All grafts with flow greater than 45 ml/min remained open.

Progressive and Late Obstruction of an Aorto-Coronary Venous Bypass Graft

Progressive late obstruction of an aorto-coronary venous bypass graft is reported in a 44-year-old man who died of bi-ventricular failure 114 days after surgery. The first portion of the vein graft had a residual lumen of one mm. Histology showed marked intimal fibrosis. Mechanism for this occlusion and fibrosis is unclear. This representsc the first documented case of late obstruction of an aorto-coronary bypass graft with angiographic evidence of early postoperative patency.

Factors influencing hemolysis in valve prosthesis

Abstract Hemolysis was found in 67.3 per cent of 208 patients with valve prosthesis. The diagnosis of hemolysis was based on an increased serum lactic dehydrogenase activity (SLDH) with sub-unit liver/heart

Porcine versus pericardial bioprostheses: A comparison of late results in 1,593 patients

From 1976 to 1988, 1,593 patients underwent valve replacement with a porcine (878 patients) or a pericardial bioprosthesis (715 patients). There were 701 aortic, 678 mitral, and 214 multiple-valve replacements. Follow-up was obtained for 1,559 patients (98%). Early mortality was 9% (79 patients) in the porcine valve group and 5% (37 patients) among patients with a pericardial valve (p less than 0.01). Late survival after replacement with porcine valves was 80% +/- 1% and 62% +/- 3% at 5 and 10 years, respectively. With pericardial valves, 5-year survival was 79% +/- 2%. Among valve-related complications, rates of freedom from thromboembolism, endocarditis, and hemorrhage after 6 years were similar for both valve groups. Freedom from reoperation at 6 years was also similar after aortic (96% versus 91%) or multiple-valve replacement (95% versus 88%). However, for mitral valve replacement, freedom from reoperation was significantly better with porcine valves than with pericardial valves at 6 years (92% versus 68%; p less than 0.001). This difference was mainly due to the Ionescu-Shiley valve, which accounted for 83% of primary tissue failures among pericardial bioprostheses implanted in the mitral position (10/12 patients). After 6 years, freedom from primary tissue failure of mitral valves was 92% +/- 2% with porcine and 70% +/- 11% with pericardial bioprostheses (p less than 0.0001). The degree of clinical improvement among survivors was similar with both valve types. Thus, in the aortic position, pericardial valves compare with porcine valves up to 6 years, whereas in the mitral position, the durability of the former is significantly less, mainly because of the suboptimal performance of the Ionescu-Shiley pericardial bioprosthesis.

Cardiac catheterization findings at rest and after exercise in patients following cardiac transplantation

Abstract Combined right and left heart catheterization was performed in 4 patients, 4 to 20 weeks after cardiac homotransplantation. A right heart study alone was obtained in a fifth patient. The findings at rest were at the limits of normal except for slight pulmonary hypertension and abnormally low left ventricular work and tension-time indexes. After 2 minutes of slight exercise, the heart rate increased only slightly, but the stroke index increased to a level comparable to that of the control subjects. The left ventricular end-diastolic pressure increased to more than 16 mm Hg, and the left ventricular stroke work and stroke power, as well as the tension-time index per minute, remained abnormally low. It is assumed that except for the change in heart rate, these abnormal hemodynamic findings reflect a myocardial dysfunction secondary to the rejection phenomenon or related to the denervated state of the heart. We suggest that extensive cardiac catheterization procedures may aggravate or induce rejection and should be omitted.

Blood Flow Through Aorta-to-Coronary Artery Bypass Grafts and Early Postoperative Patency: A Study of 100 Patients

Abstract Blood flow through aorta-to-coronary artery bypass grafts was measured in 100 patients who underwent insertion of a total of 157 grafts to the right (RCA), left anterior descending (LAD), or circumflex (CIRC) coronary artery or to a combination of these arteries. Angiographic evaluation was obtained in all patients in the early postoperative period. The overall patency rate was 88.5%. Mean flow was 28 ml. per minute in occluded grafts and 66 ml. per minute in patent grafts. The mean flow doubled in both groups following injection of papaverine into the graft, although 5 of the 18 occluded grafts failed to respond to papaverine. This phenomenon was not observed in patent grafts. In all but 1 occluded graft, blood flow was less than 50 ml. per minute. Only 3 of 12 grafts with a flow of 25 ml. or less remained open. It is concluded that intraoperative measurement of blood flow provides a reliable index of early postoperative patency in aorta-to-coronary bypass grafts.

Hemodynamic evaluation of the Carpentier-Edwards porcine xenograft.

The hemodynamic function of the thin-wall, glutaraldehyde-treated porcine xenograft was evaluated in 37 asymptomatic patients an average of 8 months (range 6-15 months) after operation. Three patients had a double-valve replacement. Cardiac output and simultaneous transvalvular gradients were recorded at rest and during moderate supine exercise. In 25 patients with an aortic bioprosthesis, the average mean gradient was 18 mm Hg and the effective orifice area 1.5 cm2 (range 0.5-2.8 cm2). The average aortic valve area for seven patients with a small valve (21 or 23 mm) was 1.2 cm2. During exercise, the mean gradient increased to 23 mm Hg (range 7-36 mm Hg) and the effective orifice area increased to 1.8 cm2 (range 1.0-3.8 cm2). In 15 patients with a mitral bioprosthesis, the average diastolic gradient was 6 mm Hg and the effective orifice area 2.4 cm2 (range 1.4-3.9 cm2). The average mitral valve area for 10 patients with a 27- or 29-mm valve was 2.1 cm2. During exercise, the mean gradient increased to 14 mm Hg (range 6-32 mm Hg) and the effective orifice area increased to 2.8 cm2 (range 1.5-4.8 cm2). Of the 40 valves evaluated, three had mild and one had moderate regurgitation. We conclude that the Carpentier-Edwards valve has hemodynamic characteristics similar to those of other currently used prostheses. Like other bioprostheses, small valve sizes in the aortic position have a small effective orifice area and should be used selectively according to the patients body surface area. This precaution is not required in valves 25 mm or larger. In the mitral position, all biological and mechanical valves are mildly obstructive due to leaflet, poppet or disc inertia. The Carpentier-Edwards valve has an acceptable effective orifice area in the stent sizes evaluated in this study. However, moderate gradients during supine exercise are common in the smaller valve sizes.

Thromboembolic complications with the cloth-covered Starr-Edwards aortic prosthesis in patients not receiving anticoagulants.

A comparison of the incidence of thromboembolic (TE) episodes was made in three groups of patient who underwent aortic valve replacement with the cloth-covered Starr-Edwards prostheses. Group 1 consisted of patients who received anticoagulants for either the entire period of follow-up or for a period of variable duration, after which these agents were no longer administered. When anticoagulants were stopped, 22 patients were categorized as Group 3 for study. Group 2 comprised patients who never received anticoagulants. Of the 147 patients followed in Group 1, 14 suffered one episode of TE. Six patients experienced major emboli; 3 of them died. Twenty of the 82 patients followed in Group 2 (no anticoagulants) suffered TE complications. There were 10 episodes of major emboli. Five of the 22 patients in Group 3 suffered an episode (all major) of TE. It is concluded from this study that anticoagulants should be given permanently to all patients with cloth-covered Starr-Edwards prostheses. Indeed, there is no period after operation when the incidence of TE is so low that anticoagulation may be safely discontinued.