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Biomedical subjects

P Perier

Publications and source records attributed to P Perier.

At least 37 records · Page 2Linked to original sources
PubMed1989

A 10-year comparison of mitral valve replacement with Carpentier-Edwards and Hancock porcine bioprostheses.

Two hundred fifty-three patients who underwent isolated mitral valve replacement with a porcine bioprosthesis had long-term evaluation. One hundred forty-seven patients received a Carpentier-Edwards porcine bioprosthesis and 106, a Hancock valve. There were no significant differences in preoperative clinical characteristics between the two groups. Cumulative follow-up was 1,375 patient-years. At 10 years, 93% +/- 2.5% of the patients in the Carpentier-Edwards group and 85% +/- 7.8% of those in the Hancock group were free from valve-related death (not significant), and 95% +/- 2% and 91% +/- 3.8%, respectively, were free from thromboembolism (not significant). At 10 years, 65% +/- 7.2% of the patients in the Carpentier-Edwards group and 66% +/- 7.2% of those in the Hancock group were free from structural valve deterioration (not significant), and 64% +/- 6% and 59% +/- 7.3%, respectively, were free from reoperation (not significant). We conclude that the first generation of Carpentier-Edwards and Hancock prostheses produce comparable long-term results in the mitral position.

Actuarial Analysis↗
PubMed1989

[Cardiomyoplasty. Experimental bases, operative technic, indications].

Dynamic cardiomyoplasty aims at restoring ventricular contractility by means of a skeletal muscle sutured around the heart. It consists of transferring a latissimus dorsi muscle flap onto the heart through a window created in the thoracic wall by partial resection of the second rib. The skeletal muscle may be used to reinforce the ventricular systole in ischemic or dilated cardiomyopathy, or to replace the myocardium after resection of a large aneurysm or an extensive tumour. The electronic pacing material includes an implantable cardiomyostimulator, muscle stimulating electrodes and R wave detecting electrodes. Muscular pacing begins 2 weeks after the operation, this being the time required for adhesions to be formed between the heart and the muscle. A progressive and sequential electrostimulation procedure results in the transformation of glycolytic muscle fibres that are fatigue-sensitive into fatigue-resistant oxidative fibres. The purpose of this biomechanical cardiac assistance system, where cardiac surgery is combined with plastic surgery and biomedical engineering, is to prolong life and improve its quality in patients with severe heart failure.

Assisted Circulation↗
PubMed1988

Clinical comparison of mitral valve replacement using porcine, Starr, and Bjork valves.

The choice of a cardiac prosthesis for mitral valve replacement remains controversial, and thromboembolic complications are still a major cause of morbidity and mortality in patients with mechanical valves. Because of this, permanent anticoagulation with its risks and constraints on daily life is necessary. Bioprostheses, however, are associated with a lower rate of thromboembolic events. Therefore, the need for long-term anticoagulation is minimized. These advantages are counterbalanced by the limited durability of tissue valves. In an effort to give some perspective to this balance, we compared the long-term results of three commonly used mitral valve prostheses. Three hundred patients operated on in the same institution January 1974 to December 1978 form the basis of this evaluation.

Adolescent↗
PubMed1988

[Recurrent myocardial abscess during Streptococcus B endocarditis].

The authors report a case of serious streptococcus B endocarditis with a myocardial abscess that recurred after surgery. Streptococcus B endocarditis is a rare disease which is characterized by a pronounced tropism of the organism for cardiac tissues, with severe cardiac valve mutilation and abscess formation in 40% of the cases. A myocardial abscess makes the prognosis worse and must be treated surgically during the acute phase of endocarditis. Modern imaging methods, notably trans-oesophageal two-dimensional echocardiography and computerized tomography should now be used to detect such abscesses.

Abscess↗
PubMed1988

Effect of latissimus dorsi dynamic cardiomyoplasty on ventricular function.

In our approach to dynamic cardiomyoplasty, which consists of wrapping a skeletal muscle around the heart and stimulating the former in synchrony with heart contractions to augment ventricular contractility, we have transferred a latissimus dorsi muscle flap to the heart by way of a partial resection of the second rib and subsequently suturing the muscle flap around the ventricles. The muscle flap is stimulated by a Cardio-Myostimulator burst-pulse generator (Medtronic SP 1005) connected to intramuscular electrodes. In preclinical animal research, the latissimus dorsi muscle flap was shown to maintain adequate contractile force and to increase its fatigue resistance by gradual conversion of glycolytic-fatigue-sensitive-to-oxidative-fatigue-resistant muscular fibers (100%). Histochemical and biochemical studies of chronically stimulated muscles showed a total transformation of muscle fast myosin to slow myosin with characteristics similar to those of myocardium. Electron microscopy showed preserved myofibrillar cytoarchitecture and increased mitochondrial density in the cell. At 9 months, cardiac output and ultrasonic Doppler studies showed a significant increase in ventricular function (cardiac output, +21%; peak blood velocity, +40% -80%; and stroke volume, +98% -102%) during muscle stimulation. In the clinical situation, long-term (range of follow-up interval, 4-42 months) beneficial cardiac effects of cardiomyoplasty have been documented in eight patients with various pathologies (ventricular tumor, left ventricular aneurysm, ischemic disease, and dilated cardiomyopathy). Our current understanding of this process is that dynamic cardiomyoplasty acts in two ways: 1) it promotes more vigorous systolic contraction, and 2) it appears to limit heart dilatation.

Animals↗
PubMed1988

Dynamic cardiomyoplasty: a surgical approach for ventricular assistance.

Dynamic cardiomyoplasty involves the use of an electrically stimulated skeletal muscle wrapped around part of the heart to restore or augment myocardial contractility. In our approach, a Latissimus Dorsi muscle flap (LDMF) is transferred to the heart via a partial resection of the second rib, and sutured around the ventricles. The muscle flap is stimulated in synchrony with the heart contractions with bursts of impulses delivered by a "Cardio-Myostimulator" implantable pulse generator via intramuscular electrodes. The object of this study was to identify features of muscle stimulation and to measure the efficacy of L.D. cardiomyoplasty in increasing cardiac output, using an ultrasonic Doppler technique. This report shows the results obtained for goats in which such procedures were performed. Ultrasonic measurements were recorded at the time of cardiomyoplasty and 3-6 months later, during which period the muscle was put progressively into use by slowly increasing the burst frequency content, number of pulses as well as the heart-muscle contraction ratio (3:1, 2:1, 1:1). This postoperative muscle stimulation protocol takes into account the delay of gradual conversion of fast-twitch glycolytic muscular fibers into slow-twitch oxidative, fatigue-resistant fibers, as well as the healing time after cardiomyoplasty required for the muscle flap to recover collateral blood circulation and to adhere to the heart. Results show that synchronous burst stimulation of the muscle flap increases the blood peak velocity in the descending aorta (+36 +/- 8%) and increases the left ventricular stroke volume (+70 +/- 14%).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Left ventricular outflow obstruction after mitral valve repair (Carpentier's technique). Proposed mechanisms of disease.

Left ventricular outflow tract obstruction (LVOTO) after mitral valve repair by Carpentier's technique has been recently reported in the literature. To assess the mechanisms of this phenomenon, we investigated 307 mitral valve repairs performed between July 1985 and December 1986. Incidence of LVOTO related to the mechanism of the mitral insufficiency and to the etiology demonstrates a direct relation to preoperative mitral valve prolapse (posterior leaflet +/- anterior leaflet) of degenerative origin. No LVOTO occurred after rheumatic mitral insufficiency repair regardless of size of the left heart cavities or of the prosthetic ring. Intraoperative and surficial two-dimensional echocardiography, color Doppler methods, and cardiac catheterization were used to investigate the mechanisms leading to LVOTO. Nonspecific modifications induced by reduction in size of the mitral annulus by the prosthetic ring (anterior displacement of the posterior ventricular wall and of the posterior mitral leaflet and narrowing of the mitroaortic angle) are not sufficient to explain the LVOTO. The association of mitral leaflets (composed of excess tissue and opposed to flow by a perpendicular position attributable to a narrow mitroaortic angle) and geometric left ventricular modifications (responsible for the superposition of mitral inflow to ventricular outflow) also qualifies as a mechanism for the induction of LVOTO after mitral surgical repair.

Cardiac Catheterization↗
PubMed1986

Long-term results of valve repair in children with acquired mitral valve incompetence.

From March 1969 to March 1984, 89 children aged 2 to 12 years (mean 8.3 +/- 2.5) with acquired mitral valve incompetence underwent mitral repair using Carpentier's techniques. There were 84 cases of rheumatic valve disease, four cases of endocarditis, and one case of Barlow's syndrome. Valve dysfunction was classified into three types: type I (normal leaflet motion), five patients; type II (prolapsed leaflet), 74 patients; and type III (restricted leaflet motion), 10 patients. Cumulative follow-up was 546 patient/years. At 10 years, 90% of the patients were still alive, with an incidence of valve-related death of 5.5%; 98% of the patients were free of thromboembolism, 78% were free of reoperation, and 69% of the patients were free of any complications related to valve repair. We conclude that whenever feasible (92% of the cases in our experience), mitral valve repair using valvuloplasty techniques is the preferred procedure in the surgical treatment of acquired mitral valve incompetence in children.

Child↗
PubMed1985

The third generation Carpentier-Edwards bioprosthesis: early results.

The current status of valve replacement was reviewed by analyzing six groups of 100 consecutive patients, each receiving the standard Carpentier-Edwards bioprosthesis, the Starr-Edwards valve or the Björk-Shiley valve in the mitral or aortic position and operated on by the same surgeons in the same institution during an identical time frame. Data were evaluated for valve failure, reoperation, thromboembolism and valve-related deaths. Long-term results up to 9 years showed the superiority of bioprostheses over mechanical valves in terms of valve-related deaths and thromboembolic and anticoagulant complications for a similar rate of valve failure. Persistent drawbacks associated with valvular bioprostheses, namely, transvalvular gradients, limited durability and tissue calcification in young patients, led to continual improvements in valve design and preservation techniques and the development of the third generation Carpentier-Edwards bioprosthesis: the supraanular porcine valve and pericardial valve. The supraanular porcine valve was designed with the aim of decreasing the transvalvular gradient, decreasing turbulence, increasing longevity and decreasing calcification. The pericardial valve was designed with the aim of improving hemodynamics in small-sized orifices, improving mounting techniques to avoid fixation sutures at the commissures, achieving a flexible stent and improving preservation. Between July 1980 and October 1984, there were 391 supraanular porcine and 61 pericardial valves implanted. The supraanular valves were used for three purposes: isolated aortic, isolated mitral and mitral valve replacement associated with tricuspid anuloplasty. The pericardial valves were used for isolated aortic valve replacement. Short-term results (1 to 4 years) are presented concerning the clinical use of these third generation bioprostheses.

Aortic Valve↗
PubMed1985

Reversibility of muscular ischemia: a histochemical quantification by the nitroblue tetrazolium (NBT) test.

The degree of muscular ischemia and its reversibility can be quantified in the early stages. This histochemical enzymatic study utilized Nitroblue tetrazolium (NBT) which when reduced by tissue dehydrogenase produces a blue pigment: "formazan." Seventy Wistar rats were subjected to transient hindlimb ischemia by means of a tourniquet for 3, 6, 9, 12, 15 and 18 hours, followed by reperfusion. Microsurgical muscle biopsies were obtained in each rat at 1 and 12 hours, and 3, 7, 14 days after reperfusion. Time increased in muscle staining demonstrated a succino-dehydrogenase deficit confirmed by clinical and histopathological follow-up. NBT staining time was 2 minutes (+/- 8 sec.) in the control group, between 2 and 6 minutes in the reversible ischemia group (rats with 3 and 6 hours of tourniquet), and more than 9 minutes (+/- 14 sec.) in the irreversible ischemia group (animals with more than 9 hours of tourniquet). In vascular surgery and in limb reimplantation this protocol is a practical method of evaluating cytoplasmic enzymatic activity and the status of myofibrillar oxidation in the early phases of ischemic injury, before histologic changes are clearly delineated.

Animals↗
PubMed1985

[Transformation of skeletal muscle by progressive sequential stimulation with a view toward its use as a myocardial substitute].

Progressive sequential stimulation of a skeletal muscle using trains of 30 Hz impulses with increasing frequencies from 20/min. to 80/min. within 3 months, allowed us to obtain in goats a transformation of the fast twitch glycolytic muscular fibers into fatigue resistant slow twitch oxidative muscular fibers. The conditioned muscle can be used in the treatment of various myocardial lesions or to reinforce cardiac contractility in severe cardiac insufficiencies. The first clinical case successfully operated upon is reported.

Adult↗
PubMed1985

Comparative evaluation of aortic valve replacement with Starr, Björk, and porcine valve prostheses.

Three groups of 100 consecutive patients with aortic valve disease who were operated on between 1974 and 1978 underwent long-term evaluation. There were 100 aortic valve replacements with porcine bioprosthetic valves (group I), 100 with Starr valves (group II), and 100 with Björk valves (group III). There were no significant differences in the preoperative clinical conditions of the patients in the three groups. Cumulative follow-up was 1688 patient-years. Incidence of valve-related death at 8 years was 4 +/- 2.3% in group I, 13 +/- 3.6% in group II, and 13 +/- 3.8% in group III (p less than .05). At 8 years 95 +/- 2.8% of the patients in group I were free of thromboembolism, compared with 81 +/- 4.8% of those in group II and 84 +/- 4.2% of those in group III (p less than .002). The actuarial risk of a reoperation at 8 years was 16 +/- 6% in group I, 5 +/- 2% in group II, and 2 +/- 1.6% in group III (p less than .025 group I vs group III). At 8 years 98 +/- 1.2% of the patients in group I were free of anticoagulant-related complications, compared with 88 +/- 3.8% of those in group II and 86 +/- 3.9% of those in group III (p less than .005). We conclude that at 8 years porcine bioprosthetic valves performed better than mechanical valves, taking into consideration thromboembolism, anticoagulant-related hemorrhage, and valve-related death.

Actuarial Analysis↗
PubMed1984

[Comparative evaluation of various methods of treatment of mitral valve diseases. Apropos of 4 series of 100 patients operated on using the Starr prosthesis, Bjork prosthesis, bioprosthesis and valve reconstruction].

The results of 4 groups of 100 patients undergoing mitral valvuloplasty (group I), isolated mitral valve replacement by a bioprosthesis (group II), a Starr-Edwards prosthesis (group III) and a Björk prosthesis (group IV) between 1974 and 1977 were compared. The selection of patients for each group was identical and made according to strict criteria. The average age was between 47.1 +/- 12.5 years and 51.8 +/- 10.5 years according to the particular group; the average functional classification was 2.4 +/- 0.4 to 2.5 +/- 0.6; the average cardiothoracic ratio was 0.58 +/- 0.07. Most patients were in atrial fibrillation. Ninety-seven per cent of patients were followed-up by questionnaires. The results were expressed with respect to simple clinical events used in all previously reported series. The long-term mortality was identical in the 3 groups undergoing valve replacement (40 p. 100 at 7 years) but was much less in the group undergoing valvuloplasty (18 p. 100 at 7 years). The mortality rate due to valvular problems was significantly less in the valvuloplasty group (2 p. 100 at 7 years) than in the groups with mechanical prostheses (20 p. 100 at 7 years). Intermediate results were observed in the bioprosthetic group (9 p. 100 at 7 years). Thrombo-embolism was significantly less common in the groups undergoing valvuloplasty and bioprosthetic valve replacement (2 p. 100 and 6 p. 100 at 7 years) than in the group with Starr-Edwards and Björk prostheses (30 p. 100 and 32 p. 100 at 7 years).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Comparative evaluation of mitral valve repair and replacement with Starr, Björk, and porcine valve prostheses.

Four hundred consecutive patients with isolated mitral valve disease who were operated on between 1974 and 1977 underwent long-term evaluation. In this group there were 100 valve repairs, 100 porcine valves, 100 Starr valves, and 100 Björk valves. There were no significant differences in the preoperative clinical conditions of the patients in the four groups. Cumulative follow-up was 2058 patient-years. We concluded from the data that mitral valve repair was associated with fewer valve-related complications than valve replacement. Thromboembolism was the most significant parameter with respect to determining long-term results of the use of the porcine, Starr, and Björk valve prostheses.

Actuarial Analysis↗