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Biomedical subjects

C Acar

Publications and source records attributed to C Acar.

At least 109 records · Page 6Linked to original sources
PubMed1990

Operative findings after percutaneous mitral dilation.

Ten patients were operated on within one hour to 3 months after percutaneous mitral dilation. Operative analysis of the lesions demonstrated hemopericardium (n = 3), acute mitral insufficiency (n = 7), left atrial thrombus (n = 2), and atrial septal defect (n = 3). A conservative treatment of the mitral valve lesion was performed in 6 patients. All patients had uneventful postoperative courses. The complications presented in this series were either due to technical error or occurred in patients with relative contraindications to percutaneous mitral dilation (calcified commissures).

Acute Disease↗
PubMed1990

Abdominal aortic aneurysmectomy in renal transplant patients.

Because renal transplantation is allowing an increased number of patients to survive for prolonged periods, abdominal aortic aneurysms can be expected to occur with growing frequency in these patients. Surgical management of such cases involves the provision of allograft protection. To date, the literature contains 15 reports of abdominal aortic aneurysms in renal allograft recipients. We describe a 16th case and discuss the management of these patients.

Journal Article↗
PubMed1990

Absorbable rings for pediatric valvuloplasty. Preliminary study.

Secondary valvular stenosis is a significant risk of annular ring implantation during valvular repair in children. To avoid this problem, we have developed an absorbable prosthetic ring (APR), which induces the generation of a biologic fibroelastic ring with mitotic capability and thereby allows atrioventricular annulus growth with age. Twelve polydioxanone (PDS) biodegradable APRs were surgically implanted in immature goats. To avoid possible embolic complications from ring fragments during the absorption period, APRs were covered with an extensible sewing sheath of high-porosity polyester, allowing contact between the PDS, blood, and endocardium. Four APRs were implanted into the right atrial cavity, four in the tricuspid position, and four in the mitral position. Histological studies at 6 months showed a considerable amount of remaining PDS. At 1 year, only small residual fragments of PDS were present, surrounded by collagen and elastic fibers as well as fibroblasts with mitotic activity. This histological structure represents a new biologic fibroelastic ring, which has originated from PDS rings. Echocardiography at 12 months showed that the elasticity of APRs and fibrotic tissue allows normal systolic and diastolic valve motions. These findings, which demonstrate histological changes in native valve annuli as well as stable and elastic annuloplasty without secondary stenosis in growing animals, call for new studies involving hearts with valvular disease.

Animals↗
PubMed1990

[A new technique of simultaneous revascularization of coronary vessels and lower limbs. 4 cases].

Management of patients with concomitant coronary and aorto-iliac atherosclerosis is controversial. It is universally accepted that coronary artery surgery should precede aorto-iliac reconstruction. The technique described consists of an ascending aorta to bifemoral graft. This technique allows combined surgery of the coronary arteries and to the lower limbs without opening the peritoneum.

Aorta↗
PubMed1990

[Treatment of type A aortic dissection by exclusive glueing].

From 1984 to 1990, 24 patients suffering from type A aortic dissection were treated by directly suturing the entry orifice of the dissection and glueing (gelatin-resorcin-formaldehyde glue) the dissected aortic tunicae, without any prosthetic replacement. Associated aortic insufficiency in 21 patients was treated by valve replacement (8 patients) or plasty (8 patients). Deep hypothermia with circulatory arrest was required in 13 patients, whose aortic arch was involved by the dissection. All patients survived the operation. All these patients were followed up from 6 to 60 months. All were controlled with Doppler echography. In addition, 21 of them were examined with angiography, 17 with CT and 5 with MRI. 21 patients had an ascending aorta and an apparently normal aortic arch. Limited dissection of the descending aorta, requiring no second surgery, was noted in 2 patients. Persisting dissection of the descending aorta was present in 13 patients. Valve replacement was necessary 18 months later in 1 patient. Heart transplantation was necessary 14 months later in a patient suffering from associated cardiomyopathy. These results demonstrate that aortic glueing is effective and safe in the middle term for the treatment of aortic dissection.

Adult↗
PubMed1990

Studies of controlled reperfusion after ischemia. XVII. Reperfusion conditions: controlled reperfusion through an internal mammary artery graft--a new technique emphasizing fixed pressure versus fixed flow.

UNLABELLED: This study tests the usefulness of delivering a controlled reperfusate through an internal mammary graft after acute ischemia by applying a percutaneous technique of mammary artery cannulation and compares reperfusion at fixed pressure versus fixed flow. METHODS: Twenty-one dogs underwent 2 hours of ligation of the left anterior descending coronary artery followed by regional controlled revascularization on total vented bypass. A reperfusion catheter was introduced percutaneously from the brachial artery into the internal mammary artery. Five dogs received normal blood reperfusion at 50 mm Hg pressure, and eight dogs received a regional blood cardioplegic reperfusate at 50 mm Hg before reperfusion with normal blood. Eight additional dogs received regional cardioplegia at 30 ml/min for 20 minutes. Coronary vascular resistance, segmental shortening (ultrasonic crystals), tissue water content, and histochemical damage (triphenyltetrazolium chloride stain) were assessed. RESULTS: Reperfusion with normal blood increased coronary vascular resistance progressively to 62% above initial values (p less than 0.05) and failed to restore regional contractility (9% +/- 6% systolic shortening, p less than 0.05). In contrast, coronary resistance remained low throughout blood cardioplegic reperfusion at fixed pressure and the reperfused muscle recovered immediate contractility (73% systolic shortening, p less than 0.05). Controlled reperfusion at a fixed flow rate resulted in pressure that ranged from 30 to 80 mm Hg, slightly less recovery of systolic shortening (57%), and less return of contractile reserve (81% versus 114%, p less than 0.05). Regional blood cardioplegic reperfusion limited edema formation (79.5 versus 82% water content, p less than 0.05) and histochemical damage (11% versus 50% area of necrosis/area at risk, p less than 0.05). CONCLUSION: An internal mammary artery graft can be used effectively in the setting of acute ischemia if a controlled blood cardioplegic reperfusate is delivered through it to ensure limitation of histochemical damage, low reflow phenomenon, and restoration of immediate segmental contractility. Controlled-pressure reperfusion seems superior to fixed-flow reperfusion. A technique is described that may allow preoperative insertion of the reperfusion catheter in the internal mammary artery in the catheterization laboratory.

Adenosine Triphosphate↗
PubMed1990

Studies of controlled reperfusion after ischemia. XVIII. Reperfusion conditions: attenuation of the regional ischemic effect by temporary total vented bypass before controlled reperfusion.

This study tests the hypothesis that total vented bypass can attenuate the regional ischemic effect during a defined time interval before controlled blood cardioplegic reperfusion. Thirty-three dogs underwent 2 or 4 hours of occlusion of the left anterior descending coronary artery and then received a regional blood cardioplegic reperfusate on total vented bypass. Cardiopulmonary bypass and reperfusion were started after 2 hours of ischemia in eight dogs, and after 4 hours of ischemia in 25 others. Among the 25 dogs, seven had total vented bypass started after the first 2 hours of the 4 hours of regional ischemia. Segmental shortening (ultrasonic crystals), tissue water content (wet/dry weight), and histochemical damage (triphenyltetrazolium chloride stain) were assessed 2 hours after reperfusion. Dogs reperfused after 2 hours of ischemia recovered 73% +/- 8% of control systolic shortening and sustained only 11% triphenyltetrazolium chloride nonstaining. Dogs undergoing 4 hours of regional ischemia, but with total vented bypass 2 hours before reperfusion had improved recovery of systolic shortening (49% versus 31%, p less than 0.05), limited epicardial edema (79.6% versus 81.1% water content, p less than 0.05), and reduced histochemical damage (24% versus 39% triphenyltetrazolium chloride nonstaining, p less than 0.05). These findings imply that institution of total vented bypass during ischemia attenuates the infarct process, increases regional recovery of contractility, limits edema and restricts histochemical damage, and may be a useful adjunct to myocardial salvage when controlled reperfusion can be provided.

Adenosine Triphosphate↗
PubMed1990

[Benign tumors of the heart (excluding myxoma). Experience with 9 surgically treated cases].

Benign non myxomatous cardiac tumors are rare. Between 1968 and 1988, 9 patients presenting benign non myxomatous cardiac tumors were operated in our institution. Tumors were: 2 rhabdomyomas, 2 lipomas, 2 fibromas, 1 pheochromocytomas, 1 mesothelioma and 1 papillary fibroelastoma. Total excision was possible in all cases but one (multiple fibromas). We hereby present a review of the literature on the subject. We focalize on the new imagery techniques in order to help the diagnosis and on the new surgical possibilities (cardiomyoplasty) which make possible complete surgical excision.

Adult↗
PubMed1990

[Arterial injuries caused by the insertion of an intra-aortic counterpulsion balloon].

Insertion of an intra-aortic counterpulsion balloon was necessary following 283 surgical procedures with the heart pump at Hospital Broussais. One instance of vascular trauma at the site of insertion of the balloon was reported in 36 cases (13 p. cent). This was treated according to the severity of the arterial lesion with the following techniques: closure with Goretex venous patch (n = 25), short ilio-femoral by-pass (n = 9) and extra-anatomical femoro-femoral by-pass (n = 2). The overall mortality of the patients who required an intra-aortic balloon was 19 p. cent, including one case of retrograde aortic dissection at the site of insertion of the balloon. The morbidity related to the insertion of the balloon was as follows: one leg amputation, two disabling intermittent claudication episodes.

Arteriosclerosis↗
PubMed1989

Aberrant right subclavian artery aneurysm: report of a case and review of the literature.

Aneurysms of an aberrant subclavian artery are rare. They are usually secondary to atherosclerosis. Dysphagia is the most common presenting symptom. The diagnosis of these lesions is most easily established by CT scan. Biplane arteriography is necessary in order to clearly analyze the aortic arch and its branches. Surgical resection is usually indicated. Numerous procedures have been proposed to treat these lesions and controversy exists concerning the best surgical technique. We treated a patient who suffered from an aneurysm of an aberrant subclavian artery. The surgical technique is detailed as well as a review of all the cases of the literature.

Aged↗
PubMed1989

Cardiogenic shock after acute coronary occlusion. Pathogenesis, early diagnosis, and treatment.

The early natural history of left anterior descending coronary artery (LAD) occlusion and the development of cardiogenic shock was studied in 35 open chest anesthetized dogs observed for 6 hours. Six control dogs underwent LAD isolation without occlusion, 13 underwent isolated LAD occlusion to simulate single vessel disease, and 14 underwent LAD occlusion and a 50% left circumflex coronary artery (LCA) stenosis to stimulate multi-vessel disease. Control dogs undergoing anesthesia showed no significant changes in hemodynamics after 6 hours. All dogs with single vessel disease survived and developed immediate and persistent dyskinesis of the anterior wall, a compensatory hypercontractility of remote muscle (131% of control)*, slight energy and substrate depletion and anaerobic metabolism (increased G6P)* despite maintenance of "normal" blood flow through the LCA. In contrast, early mortality was 57% in simulated multi-vessel disease as intractable ventricular fibrillation and/or cardiogenic shock caused the deaths of 7 of 13 dogs (57%)*. Remote muscle became progressively hypocontractile (61% of control)* and caused progressive reduction in stroke work index (less than or equal to 0.5 g x m/kg)*. Remote muscle showed moderate substrate and energy depletion (greater than or equal to 60% fall of ATP and CP, 37% fall of glutamate)* and more pronounced evidence of anaerobic metabolism (G6P rose 373%)* despite "normal" blood flow. These findings suggest that remote muscle is the principle determinant of mortality after an otherwise non-lethal cardiac event.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Left thoracotomy: an alternative to median sternotomy in coronary bypass in cases of pericardial adhesions].

Coronary bypass on the circumflex artery network was performed by left thoracotomy in 5 patients. All presented with pericardial adhesions due to coronary artery surgery (n = 4) or to mediastinal irradiation (n = 1). The left thoracotomy route provides excellent exposure of the lateral aspect of the heart and may be an advantageous alternative to sternotomy when pericardial adhesions are present.

Coronary Disease↗
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↗
PubMed1989

Studies on prolonged acute regional ischemia. V. Metabolic support of remote myocardium during left ventricular power failure.

This study tests the hypothesis that metabolic support of remote "nonischemic" myocardium during acute infarction will reverse the trend toward cardiogenic shock. Thirty-seven dogs underwent ligation of the left anterior descending coronary artery and 50% stenosis of the circumflex coronary artery. Irreversible ventricular fibrillation developed in 11 of them. The 26 survivors were observed for up to 6 hours; global and regional left ventricular function (cardiac index, stroke work index, ultrasonic crystals) and regional blood flow (radioactive microspheres) were measured. After 2 hours, eight dogs received an intravenous infusion of glutamate/aspartate, glucose-insulin-potassium, coenzyme Q10, and 2-mercapto-propionyl-glycine for 4 hours. Five dogs received the mannitol infusion to raise serum osmolarity 30 mOsm. Four additional dogs received the intravenous substrate infusions over 4 hours without undergoing ischemia. The substrate infusion for 4 hours caused no change in regional or global cardiac function in the four control dogs. Three of nine untreated dogs died of cardiogenic shock, and progressive left ventricular power failure occurred in the six others (40% decrease in cardiac index, 50% decrease in stroke work index, p less than 0.05) because of persistent dyskinesia in the left anterior descending region (-40% of systolic shortening, p less than 0.05) and hypocontractility in the circumflex region (48% of control systolic shortening, p less than 0.05), despite normal transmural blood flow in the posterior left ventricular wall (76 ml/100 gm/min). In contrast, in treated dogs, hypercontractility recovered in the circumflex segment (138% of systolic shortening) and stroke work index rose to control levels (91%) without a change in regional blood flow. Mannitol infusion did not improve hemodynamics or avoid the development of progressive left ventricular power failure. We conclude that cardiogenic shock after myocardial infarction is due, in large part, to impaired ability of "nonischemic" myocardium to maintain hypercontractility. This limitation can be prevented by metabolic support of viable muscle, and the data imply that intravenous substrate infusions may be helpful before definitive treatment (i.e., coronary artery bypass grafting) is undertaken.

Animals↗