Biomedical subjects
Publications and source records attributed to E S Hanna.
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The risk-benefit relationship of open heart surgery in octogenarians is not well established. Eighty consecutive patients over the age of 80 who underwent cardiac operations under cardiopulmonary bypass were evaluated. Twenty-five patients were in functional class IV, 42 in class III, and 13 in class II. Forty-four patients had only coronary artery bypass grafts (CABG), 12 only aortic valve replacement (AVR), 6 only mitral valve replacement (MVR), 12 CABG and AVR, 4 CABG and MVR, 1 CABG and aneurysmectomy, and 1 had resection of left atrial myxoma. Operative mortality (within 30 days) was 12.5% for the group. Mortality was related to bleeding, left ventricular failure, primary ventricular fibrillation, pulmonary failure, and renal failure. Mortality was higher in patients with (1) advanced functional class, (2) mitral valve replacement, (3) postoperative hemorrhage, and (4) associated pulmonary disease. While a generally conservative approach is recommended for octogenarian patients, many with life-threatening cardiac disease, especially those free of major multisystem illnesses, should not be denied the benefit of surgical treatment.
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Since argon laser radiation (454-514 nm) can vaporize human clots, we determined whether the absorption of laser energies can differ among different types of blood clots. Thus we performed spectrophotometric studies and examined the ability of this laser to penetrate red cell rich and red cell poor clots. Fifty-four red cell rich and red cell poor clot samples, varying in depth from 1.8 to 5.0 mm, were subjected to 3, 5 and 7 watts from an argon laser beam. At a given power intensity, the deeper the red cell rich clot, the longer was the time needed to penetrate the clot. The higher the power used, the shorter was the red clot penetration time. In contrast, all power levels used up to 5 minutes did not penetrate any of the varying depths of red cell poor clots. Spectrophotometrically, the red cell rich clot had an absorption curve typical of hemoglobin pigment while the red cell poor clot, in the absence of hemoglobin, had poor absorption between 350 and 600 nm and was unable to absorb argon laser energies. Thus, the argon laser provides a therapeutic modality for human red cell rich clot dissolution but the present approach does not appear to be effective against red cell poor clots.
We report three patients who developed iatrogenic severe left main coronary artery stenosis. In two, it was secondary to coronary cannulation during aortic valve replacement and in one it followed distention of the artery during balloon dilatation of a proximal lesion in the left anterior descending artery. In all three, the stenosis was clinically manifest a few months after the intervention. All were successfully treated by aortosaphenous coronary bypass. A common mechanism for the three cases may be mechanical distention of the left main coronary artery resulting in intimal damage with secondary fibrosis and stenosis. The percutaneous transluminal coronary angioplasty-related stenosis is, to our knowledge, the first reported case of this nature, and represents a previously unrecognized complication of this procedure.
During the period 1965-1983, 270 patients underwent resection of abdominal aortic aneurysm. In 70 patients (26%) the aneurysm was ruptured. Overall hospital mortality of patients with ruptures was 34%. Five patients died before the graft could be completed. Common denominators associated with mortality were hypotension, renal failure, cardiac arrest, and postoperative hemorrhage. The average age over the first 10 years was 68, but subsequently, has risen gradually, with a corresponding increase in mortality despite improved surgical technique and postoperative care. Only with more widespread elective resections and earlier diagnosis of rupture followed by prompt operative management, can the outlook for patients with abdominal aortic aneurysm be improved.
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Laser energies can be transmitted through flexible optical fiber to vaporize and penetrate coronary atherosclerotic and thrombotic obstructions. There are risks and complications involved in this therapy, however, including perforation, aneurysm formation, and thromboembolic risks, and further research is needed to render the laser recanalization procedure safe.
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We propose that circumstances exist in which angiography is not necessary or is unwarranted for the diagnosis and treatment of carotid arterial disease. High quality real-time B-mode ultrasonographic imaging, combined with both pulsed gated, and continuous wave Doppler analysis, shows a remarkably close correlation with the pathologic abnormality identified at operation. Scanning in the vascular laboratory not only provides quick, noninvasive, accurate assessment of the atherosclerotic disease, it can also provide plaque and blood flow detail not previously attainable. Carotid surgery can be effectively and safely performed in selected patients with the aid of ultrasonography and Doppler analysis without the need for invasive angiographic imaging.
Sixty-six patients with pulmonic valvular stenosis were evaluated by cardiac catheterization and cine-angiography over the past four years in a recently established cardiovascular center in Syria. Patients were divided according to severity of pressure gradient across the pulmonic valve into three groups: Group I (25 patients) had gradients below 50 mm. Hg, Group II (14 patients) had gradients between 50 and 100 mm. Hg, and Group III (27 patients) had gradients exceeding 100 mm. Hg. Clinical symptoms and signs including dyspnea on exertion, palpitation, cyanosis, and characteristics of the murmur and the pulmonic second sound were correlated with severity and grouping along with electrocardiographic and radiographic findings. Valvulotomy was carried out in 23 patients (35%). Short term clinical results were excellent in 19 patients, but long term course of the non-operated and post-operative cases is yet to be established.
Laser energy delivered through optical fibers can produce potent controlled thermal dissolution of human coronary obstructive disease, thus widening the stenotic vascular lumen. The ease of vaporization and penetration depends not only on the physical properties of the laser beam but also on the physical characteristics of the atherosclerotic plaque. Lipid-laden plaques are more easily vaporized compared with plaques that are heavily calcified. In atherosclerotic animal models studied in vivo, laser radiation produced a charred lining around the evacuated area and rapid regeneration of a new endothelial lining. After several weeks, the laser-induced crater was still evident, and thrombogenesis was not a significant complication. Focal aneurysmal dilatation may develop when there is thermal injury of the medial layer, and acute perforation can occur if severe laser burn is extended beyond the adventitial layer. Further technical advances and achievements are needed before laser recanalization becomes a clinical reality.