Biomedical subjects
Publications and source records attributed to C Acar.
Mitral valve replacement, using a cryopreserved mitral homograft, was performed in a 49-year-old patient with calcified mitral stenosis. Postoperative course was uneventful. Transesophageal echocardiography performed 6 months later showed normal function of the mitral homograft.
Aortomyoplasty consists of wrapping the latissimus dorsi muscle (LDM) around the ascending aorta and electrostimulating it during diastole. The ascending aorta will act as an ectopic neo-ventricle compressed during diastole, thus reproducing the effects of long-term diastolic counterpulsation. In 5 goats, the right LDM was transferred to the thoracic cavity after removal of the second rib. The ascending aorta was enlarged by a pericardial patch and wrapped with the LDM. Postoperative electrostimulation was delivered in a counterpulsating manner. Hemodynamic studies were performed at 12 and 24 months postoperatively. Percent increase in the subendocardial viability index (diastolic pressure-time index/systolic tension-time index) was calculated using unassisted and assisted cardiac cycles with the stimulator off versus the stimulator on at a 1:1 ratio in the basal state and after acute heart failure was induced by the administration of high doses of propranolol hydrochloride. Diastolic counterpulsation of the ascending aorta resulted in significant improvement in the subendocardial viability index long term, both in basal state conditions and after induced cardiac failure. During heart failure, aortomyoplasty increased the cardiac output and decreased systemic vascular resistance. Histopathologic studies up to 24 months showed preservation of the histologic structure of the aortic wall and no evidence of thromboembolism. Tight adhesions developed between the aortic wall (including the pericardial patch) and the LDM. The diameters of the enlarged aortas showed no significant differences compared with diameters immediately postoperatively. In conclusion, aortomyoplasty produces chronic diastolic augmentation with preservation of aortic structure. After induction of heart failure, aortomyoplasty offers efficient circulatory support.
We recently observed five cases of early thrombus formation in patients undergoing anticoagulation with subcutaneous heparin following open heart surgery. The reasons prompting surgery were as follows: one mitral valve replacement, one double valve replacement, one mitral valve reconstruction, one aortic valve replacement associated with coronary bypass. In all cases, intravenous heparin was begun on the day of surgery and replaced by subcutaneous (SC) heparin on postoperative day 1. Acute thrombocytopenia was observed between the 6th and 11th postoperative day. This was interpreted as denoting an idiosyncratic reaction to heparin which was replaced by low molecular weight heparin (LMWH) in two cases and by acenocoumarol in the other cases. Massive thrombosis of the aortic valve resulted in the death of one patient. Thrombosis of the left atrium occurred in three patients (two of whom had a transient ischemic attack (TIA)). One patient had aorto-iliac thrombosis. Successful reoperation was carried out in four of the five patients. Although heparin-induced thrombocytopenia and thrombosis [HITT] is a rare complication of heparin therapy, serial platelet count monitoring and in vitro platelet aggregation tests are mandatory in the diagnosis of this syndrome. Discontinuation of heparin is indicated as soon as the syndrome is recognized and the institution of aspirin is recommended if the thromboembolic complication requires reoperation and reexposure to heparin.
Structural changes of the arterial vasculature are of major pathophysiologic and prognostic significance in human hypertension. A high-resolution ultrasonic echotracking device was used to measure internal diameter and intima-media thickness of the radial artery, a medium-sized muscular conduit artery, in 60 hypertensive patients and in 40 age-matched control subjects. Of the 60 hypertensives, 33 were never treated and 27 were well-controlled by antihypertensive therapy. Radial artery mass and thickness/radius ratio were used to describe the radial artery structure. Radial artery mass was validated in vitro by comparing the weight of arterial segments to the ultrasonographic determination of their mass, calculated as: rho L(pi Re2-pi Ri2), where rho is the arterial wall density, L the length of the arterial segment, and Re and Ri the ultrasonic values of internal and external radii, respectively. Diastolic internal diameter did not differ among the three groups, but wall thickness, radial artery mass, and thickness/radius ratio were significantly higher in the untreated hypertensive group than in the control group. In treated well-controlled hypertensive subjects, radial artery mass and thickness/radius ratio were not different from that of control subjects. Among the population of untreated patients, significant univariate relations existed between radial artery mass and blood pressure and radial artery mass and age. In multivariate analysis, radial artery mass was independently predicted by mean blood pressure, age, and sex. Circumferential wall stress, calculated from diastolic internal diameter, wall thickness, and diastolic blood pressure, was not different in the three groups.(ABSTRACT TRUNCATED AT 250 WORDS)
Satisfactory results were obtained with the radial artery used as a conduit for coronary artery bypass. However, spasm of this conduit was observed. Human radial and internal mammary artery ring segments were studied in organ chambers. Potassium chloride, norepinephrine, serotonin and thromboxane A2 mimetic were used to obtain dose-response curves, permitting assessment of force of contraction and sensitivity. The radial artery presents stronger contractions than the internal mammary artery. The two vessels have equal sensitivity to the vasoconstrictors used. These data emphasize the hyperreactivity of the radial artery and the need for prevention of vasospasm when this vessel is used as a conduit for coronary artery bypass.
OBJECTIVE: To determine the reproducibility of radial artery mass (RAM), in hypertensive patients. DESIGN AND METHODS: In 49 patients, RAM was measured using a high resolution echotracking device (Nius-02) which allows noninvasive measurement of diameter and wall thickness of the radial artery. RAM was validated in vitro by comparing weight of arterial segments to ultrasonographic measurement and determined as RAM = r (pi Re2-pi Ri2) where r is the arterial wall density (1.06 g/cm3), and Re and Ri are values of internal and external radii, respectively. Repeatability coefficient (RC2 = SDi2/n) was 1.3 mg. RESULTS: Blood pressure was (mean +/- SD) 146 +/- 19/85 +/- 15 mmHg, radial arterial diameter was 2,449 +/- 376 microns, radial wall thickness was 302 +/- 68 microns, RAM was 28 +/- 9 mg (range 13-43 mg). CONCLUSION: These results indicate that radial artery mass can be measured using a high resolution echotracking device.
Mitral valve replacement using a cryopreserved mitral homograft was performed in a 49 year old patient with calcified mitral stenosis. The surgical technique is described. The postoperative course was uneventful. Transoesophageal echo performed 4 months later showed a normal function of the mitral homograft.
Cardiomyoplasty (CMP) is a technique of circulatory assistance using a pediculated latissimus dorsi muscle wrapped around the heart and electrically stimulated during systole. Sixty-four patients, aged 15 to 69 years (average 50.8 +/- 13 years) with cardiac failure underwent CMP between January 1985 and July 1993. The causes of cardiac failure were : ischaemic heart disease (39 cases), dilated cardiomyopathy (18 cases), cardiomyopathy following valvular heart disease (2 cases), cardiac tumours (4 cases) and congenital heart disease (1 case). Twenty-four patients underwent an associated surgical procedure. Intra and postoperative intra-aortic balloon pumping was required in 27 cases. Hospital mortality (before latissimus dorsi stimulation) was 20.3% (13/64 cases). Evaluation of the survivors 12 months after surgery showed an improvement in functional class (1.,5 versus 3.3 before CMP ; p < 0.05), in isotopic ejection fraction (27 +/- 3% versus 17 +/- 6%, p < 0.05) and cardiac index (2.87 +/- 0.63 l/min/m2 versus 2.38 +/- 0.41 l/min/m2, p < 0.05). There was no significant change in cardiac filling pressures. The number of hospital admissions for congestive cardiac failure in operated patients was 0.4 per patient per year, compared with 2.5 per patient per year (p < 0.05) before CMP. The preoperative predictive factors for late mortality were: permanent functional Class IV (NYHA), severe cardiac dilatation (cardio-thoracic ratio greater than 0.60; left ventricular end diastolic dimension > 75 mm), an isotopic left ventricular ejection fraction < 15%, severe biventricular cardiac failure and irreversible pulmonary hypertension. The actuarial 4 year survival rate was 68.3%.(ABSTRACT TRUNCATED AT 250 WORDS)
In order to analyse the results of conservative mitral valve surgery in the treatment of mitral regurgitation due to infective endocarditis, the authors reviewed the cases of 48 patients operated between 1974 and April 1993 (36 operations having been performed after 1989, a period during which only 3 patients underwent mitral valve replacement for the same indication). Thirty-four patients were operated after sterilisation of the infective endocarditis, and 14 patients were treated during the active phase. There were 32 men and 16 women with an average age of 45 +/- 13 years. In two thirds of the cases, the causative organism was a streptococcus. Half of the patients were operated during the acute stage because of their poor haemodynamic status, 5 because of residual bacterial vegetations after one or more embolic events and two because of the infection itself. On the other hand, patients were operated after the infective phase because of severe mitral regurgitation, responsible for severe symptoms (NYHA Class III) in 16 cases. From the anatomical point of view, the peroperative finding of 14 patients operated in the acute phase included dilatation of the annulus (N = 9), ruptured chordae (N = 9), perforation (N = 8) or vegetations (N = 8); in the patients operated later, the incidence of perforation and vegetations was much lower (20%) whereas dilatation of the annulus was almost constant (91%).(ABSTRACT TRUNCATED AT 250 WORDS)
Extracorporeal photochemotherapy is a recently developed immunomodulator treatment against heart and lung graft rejection. The recipient's mononuclear cells are screened and irradiated with UV-A in the presence of 8-methoxy-psoralene (8-MOP), then reinjected. We treated 4 patients who had begun to reject their heart and/or lung grafts, with this technique, using one session per week for 4 weeks, followed by one session every 2 weeks for 2 months, then one session per month. In all cases, extracorporeal photochemotherapy appeared to improve the clinical and biological status of these patients. Episodes of rejection which could not be reversed with immunosuppressor treatment alone were controlled.
A young patient suffering from acute bacterial endocarditis underwent reconstructive surgery of the mitral and tricuspid valves. One year later a recurrent endocarditis occurred that could not be controlled with antibiotic therapy. Two separate mitral homografts were used to replace both the mitral and the tricuspid valves. The homografts' papillary muscles were sutured side to side to the recipient's and a circumferential suture of the leaflet tissue was accomplished. Homograft implantation was associated with Carpentier ring annuloplasty of the atrioventricular valves. In the right sided position, the mitral homograft was oriented in an anti-anatomical manner and an inverted semi-rigid prosthetic ring of the mitral type was inserted. Clinical and echocardiographic follow up at four months was excellent.
The anatomic constraints imposed on a total artificial heart (TAH) require specific anatomic studies. A thoracic anatomic study was performed with a scanning device equipped with three-dimensional (3-D) reconstruction software on 15 male patients, between the ages of 41 to 63 years (52 +/- 6 years). All were candidates for heart transplantation. The 3-D reconstructions of the cardiovascular structures obtained from surgical anatomy data specific to TAH implantation allowed a volumetric measurement of these structures. A modeling diagram of these structures permitted reproducible quantitative measurements of the 35 geometrical parameters which characterized shape, orientation, and position of these structures within the thorax. Most of the measured parameters were characterized by low variability (coefficient of variation from 10 to 25%).
Cardiac hemangiomas are rare benign vascular tumors of the heart. To date, 23 cases have been reported. Symptoms are usually due to compression of cardiac structures or obstruction of outflow tracts. Echocardiography usually directs the diagnosis toward a cardiac mass. Enhanced-contrast computed tomographic scan or magnetic resonance imaging establishes the diagnosis of hypervascularized cardiac tumor. Coronary arteriography establishes the diagnosis by showing the characteristic tumor blush. Surgical resection is done using cardiopulmonary bypass. Long-term outcome is favorable.
We describe an unusual presentation of bacterial endocarditis due to Staphylococcus aureus in a 50 year-old woman with mitral insufficiency. The disease began by a vascular purpura without fever and a digital embolism. The source of infection was anal ulcerations. Diagnosis of endocarditis was made possible by trans-oesophagus echocardiography but not by trans-thoracic echocardiography. The patient was successfully treated by surgery associated with antibiotherapy. This observation emphasizes the indications of surgery at the acute phase of endocarditis. The anal source of endocarditis is original, no other case has been found in the literature.
The authors report the case of a 34-year-old woman, of North African origin, with mitral valve disease and abdominal aortitis. The differential diagnosis between Takayasu' disease, embolism of cardiac origin and rheumatic aortitis is discussed. Treatment of these lesions was by combined cardiac and vascular surgery in a single-stage operation.
Twenty years after its first introduction by A. Carpentier, the use of the radial artery (RA) for coronary bypass was reinvestigated because of unexpected good long term results in some patients. Since July 1989, 158 patients (pts) underwent myocardial revascularization using 189 RA grafts (31 pts received 2 grafts). The left internal mammary artery (LIMA) was concomitantly used as a pedicled graft in 151 cases and the right internal mammary artery (RIMA) in 31 cases, a free IMA graft was used in 29 cases and a saphenous vein graft in 40 cases. A mean of 2.8 graft/pt was performed. The target artery receiving the RA was: circumflex (n = 93), diagonal (n = 39), right coronary (n = 47) and LAD (n = 10). Two patients died (1.3%) and three presented a perioperative myocardial infarct (2.5%). Sternal wound infection was noted in three cases of double IMA implant. No ischemia of the hand was observed. All patients received diltiazem started intraoperatively and continued after discharge. In addition, aspirin (100 mg/day) was given at discharge. Early angiographic controls (< 3 weeks) were obtained in the first 60 consecutive patients and revealed: 73/73 patent RA grafts, 58/58 patent LIMA grafts, 16/16 patent RIMA grafts, 15/19 patent free IMA grafts and 10/11 patent vein grafts. Six patients presented a localized narrowing of the RA conduit unrelated to the anastomotic lines (spasm). Late angiographic control (6 to 24 months) was obtained after a mean follow-up of 11 months in 37 patients: 42/46 RA grafts were patent (91.3%) and free of spasm and 4 were occluded.(ABSTRACT TRUNCATED AT 250 WORDS)
BACKGROUND: Recently, satisfactory results were obtained in a series of patients in whom the radial artery was used as a conduit for coronary artery bypass. However, spasm of this conduit was observed in 4% of patients. The aim of this study was to analyze the vasoreactive properties of the radial artery and to compare them with those of the internal mammary and the gastroepiploic arteries. METHODS AND RESULTS: Human radial (56 from 15 patients), internal mammary (77 from 20 patients), and gastroepiploic (41 from 12 patients) artery ring segments were mounted on a strain gauge in oxygenated, normothermic Krebs' solution at optimal resting tension. With KCl (100 mM) serving as the control, the dose-response curves to norepinephrine, serotonin, and thromboxane A2 mimetic were obtained, permitting assessment of force of contraction and sensitivity. Functional endothelium was assessed with acetylcholine. Smooth muscle-dependent relaxation was assessed with sodium nitroprusside. The radial artery had stronger contractions to KCl than the other vessels. The radial and the gastroepiploic arteries with endothelium presented a higher contraction force than the internal mammary artery in response to norepinephrine and serotonin. The three vessels had equal sensitivities to norepinephrine and serotonin. The gastroepiploic artery had a lower sensitivity to thromboxane A2 mimetic than the two other vessels. CONCLUSIONS: This increased reactivity of the radial artery explains its propensity to spasm and emphasizes the need for antispastic drugs and platelet inhibitors when the radial artery is used for coronary artery bypass.
BACKGROUND: Left ventricular outflow tract obstruction (LVOTO) occurs in 4% to 5% of patients after prosthetic ring mitral valve repair. Major anatomic factors incriminated in the genesis of LVOTO include degenerative mitral valve insufficiency with excess leaflet tissue, nondilated left ventricular cavity, and narrow mitro-aortic angle. We have previously reported a 14% incidence of LVOTO after prosthetic ring mitral valve repair in this high-risk group of patients. Serial echo Doppler studies demonstrated an overlapping and/or inversion of the left ventricular functional compartments generating systolic anterior motion of the posterior leaflet and paradoxical opening (eversion) of the anterior leaflet. In an attempt to eliminate LVOTO after mitral valve repair, a new surgical procedure was developed in 1988 by Carpentier: the sliding leaflet technique, which reduces the height of the posterior leaflet. The purpose of this study was to analyze the results of the new technique in terms of the occurrence of LVOTO: METHODS AND RESULTS: Eighty-two patients undergoing prosthetic ring mitral valve repair between 1988 and 1991 and identified as high risk for LVOTO were operated on using the sliding leaflet technique. There were 52 men and 30 women. Ages ranged from 28 to 75 years. The surgical techniques used included prosthetic ring annuloplasty (n = 82), leaflet resection (n = 82), chordal shortening or transposition (n = 36), and other (n = 19). Intraoperative and/or immediate postoperative echo Doppler studies were obtained in all cases. Two patients (2.4%) died, and 2 (2.4%) required reoperation. Nonsignificant LVOTO was identified in 2 cases (2.4%), in whom instantaneous maximal subaortic gradients were 20 and 18 mm Hg, respectively. CONCLUSIONS: This study was not done on a concomitant series of patients but on patients with the same type of pathology. It demonstrates that (1) the sliding leaflet technique eliminates significant LVOTO in the high-risk patients; (2) the sliding leaflet technique is associated with a low mortality; and (3) no reoperations for mitral insufficiency were required in this series.