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Biomedical subjects

R Karam

Publications and source records attributed to R Karam.

28 records · Page 2Linked to original sources
PubMed1991

The hemodynamic effects of intravenous norepinephrine versus epinephrine and phenylephrine in patients with ischemic heart disease.

The hemodynamic effects of an intravenous bolus of norepinephrine 10 micrograms, phenylephrine 100 micrograms and epinephrine 10 micrograms were investigated in 30 patients scheduled for coronary artery bypass grafting. The hemodynamic changes following norepinephrine were similar to those achieved by phenylephrine. Both drugs increased the mean blood pressure and systemic vascular resistance without any significant change of cardiac output. In contrast, epinephrine increased the mean arterial pressure and cardiac output without a significant change of systemic vascular resistance. The results suggest that intravenous norepinephrine acts similar to phenylephrine as an alpha-adrenergic agonist, while epinephrine acts predominantly as a beta-adrenergic agonist.

Adult↗
PubMed1990

Coronary reserve is depressed in postmyocardial infarction reactive cardiac hypertrophy.

After a myocardial infarction (MI), the remaining myocardium undergoes a compensatory reactive hypertrophy. Although coronary perfusion to the surviving myocardium can be an important determinant of cardiac function in this setting, there are no available data regarding myocardial blood flow in reactive hypertrophy. Accordingly, we measured coronary blood flow and reserve using radioactive microspheres in rats 4 weeks after induction of an MI by ligation of the left coronary artery. Maximal coronary dilation was induced by Carbochrome, a potent coronary vasodilator, infused at a rate of 0.45 mg/kg/min up to a total dose of 12 mg/kg. Sham-operated rats served as controls. All animals in the infarct group had a large MI affecting 30-51% (average, 41%) of the left ventricle. Left ventricular end-diastolic pressure was significantly elevated (30 +/- 6.5 vs. 8.0 +/- 2.5 mm Hg in sham-operated rats, p less than 0.01) and baseline hemodynamic indexes of cardiac performance were significantly (p less than 0.01) reduced in this group. Myocyte cross-sectional area measurements were used as an index to quantify the degree of reactive hypertrophy and indicated that the infarcted animals had, on average, a 30% hypertrophic response of the surviving left ventricular myocardium. In the infarcted animals, both coronary flow and vasodilator reserve in the surviving myocardium were depressed. Maximal coronary blood flow in the remaining myocardium was significantly lower than that measured in the sham-operated animals (839 and 1,479 ml/min/100 g, respectively; p less than 0.001). Similarly, minimal coronary resistance was significantly higher in the MI group as compared with the sham group (0.12 vs. 0.07 mm Hg/ml/min/100 g, respectively; p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Hypertensive hypertrophic cardiomyopathy or hypertrophic cardiomyopathy with hypertension? A study of 78 patients.

Hypertensive hypertrophic cardiomyopathy may be a distinctive cardiac condition resulting from hypertension. Alternatively, this disease may represent the coincidence of a common disease, hypertension, with a relatively rare cardiomyopathy. A consecutive series of patients with hypertrophic cardiomyopathy and hypertension were studied and compared with age- and gender-matched patients with cardiomyopathy alone. Thirty-nine patients were identified as having hypertension; they ranged in age from 31 to 84 years (average 60 +/- 13); 82% were greater than 50 years old; 18 (46%) were women. When these patients were compared with the age-matched group with hypertrophic cardiomyopathy alone, there were no clinical or electrocardiographic differences between the two groups. By echocardiography, the hypertensive and nonhypertensive groups had a similar incidence of systolic anterior motion (77 versus 64%, respectively), mitral annular calcification (31 versus 31%), septal thickness greater than 20 mm (56 versus 46%) and outflow tract gradient greater than 20 mm (59 versus 67%). A posterior wall thickness greater than 13 mm was more frequent in the hypertensive group (54%) compared with the nonhypertensive group (31%) (p = 0.02). The findings show that hypertrophic cardiomyopathy with associated hypertension is a disease of the elderly. But, with the exception of thicker walls, the clinical and echocardiographic features of the patients with hypertension were indistinguishable from those of the age-matched and, hence, elderly group of patients with cardiomyopathy without hypertension. These findings suggest that hypertension may make hypertrophy worse, but that it is not the primary cause of the cardiomyopathy. Thus, the condition might be better termed "hypertrophic cardiomyopathy with hypertension."

Adult↗
PubMed1989

Cocaine-induced small vessel spasm in isolated rat hearts.

Cocaine abuse has been associated with pathologic cardiovascular events including acute myocardial infarction (AMI) and sudden death. Although coronary vasospasm has been proposed as a possible mechanism, the ability of cocaine to induce coronary spasm has not been conclusively demonstrated. In these studies, isolated rat hearts were perfused with cocaine (100 micrograms to 500 micrograms/ml) for 1 minute, perfusion-fixed with glutaraldehyde, and histologically assessed for evidence of coronary spasm through light and electron microscopy. Light micrographs revealed that cocaine induced spasm in coronary arterioles up to 65 microns in diameter, whereas larger caliber vessels did not constrict. Ultrastructurally, vacuolation was observed in the endothelial and smooth muscle cells of constricted arterioles. Endothelial integrity was maintained and interendothelial junctions remained intact. Morphologic evidence of constriction was supported by data obtained from Langendorff-heart preparations in which cocaine reduced myocardial flow rate under constant pressure conditions and increased aortic perfusion pressure under constant flow conditions. Spasm induced by cocaine was prevented by the calcium entry blocker nitrendipine, but not by phentolamine, an alpha-adrenergic antagonist. The finding of small vessel spasm in this study may explain the significant number of clinical cases of cocaine-associated AMI in which the main coronary arteries appear angiographically normal.

Animals↗
PubMedDate not supplied

[Complications of percutaneous nephrostomy. Apropos of 481 procedures: the value of puncture of the median calices].

The authors report on a series of 481 percutaneous nephrostomy procedures, and describe the complications encountered. 163 percutaneous nephrostomies for drainage and 318 percutaneous stone removals, were performed between 1985 and 1995 in the Radiology Department of Hôtel-Dieu de France Hospital under fluoroscopy. One tract was needed for PN but more than one was sometimes necessary for percutaneous stone removal. Complication rate was identical to the results reported in the literature. Complications were more frequently encountered when the upper calyx was punctured (intercostal approach), mostly pleural lesions. Puncture of the middle and inferior calyx were associated with the same rate of complications, but with different degrees of severity. Major complications (80% of cases of hemorrhage, including all arteriovenous fistulae and pseudoaneurysms) were encountered with the puncture of the lower calyx while those associated with the puncture of the middle calyx were minimal. Thus, puncture of the middle calyx is the least morbid. It is recommended by the authors, whenever possible.

Adolescent↗
PubMedDate not supplied

[Selective salpingography and transcervical tubal recanalization: technique, indications, results. Apropos of 53 proceedings].

The aim of the study is to evaluate the efficacy of selective salpingography and fallopian tube recanalization as a diagnostic and therapeutic procedure when proximal tubal obstruction is present. Fifty-three procedures were performed between January 95 and March 98 in the Radiology Department of Hôtel-Dieu de France Hospital, on 53 infertile women aged between 25 and 43 years. Unilateral or bilateral obstruction was documented on hysterosalpingogram or by laparoscopy. The technique consisted of a direct fallopian tube catheterization, under fluoroscopy using an hydrophilic guidewire. Water soluble contrast material was used. Eighty-eight tubes were evaluated (35 with bilateral and 10 with unilateral obstruction, 8 single tubes). Recanalization was possible in 52 cases (97.5%). Twenty-nine patients were followed. Thirteen pregnancies were reported (45%). This pregnancy rate is however increased to 62% if we exclude the cases where other infertility problems coexisted. No complications occurred. Selective salpingography and fallopian tube catheterization is a non invasive successful technique that is extremely useful in the diagnosis and treatment of tubal obstruction in women with infertility problems. It can be performed immediately after an hysterosalpingogram when the fallopian tubes are not opacified.

Adult↗
PubMedDate not supplied

[Stereotaxic excisional biopsy of non-palpable breast lesions by the ABBI(Advanced Breast Biopsy Instrumentation) technique. Advantages. Disadvantages. Indications. Apropos of 67 cases].

OBJECTIVES: Introduce briefly: the classification of the American College of Radiology for non palpable breast lesions; and the different techniques used for stereotactic breast biopsies. Evaluate the efficiency of the ABBI technique for non palpable breast lesions and its role in breast biopsies, on the base of 67 cases. SUBJECTS AND METHOD: Sixty-seven stereotactic excisional biopsies on dedicated prone tables were performed using the ABBI technique for 21 probably benign and 46 indeterminate non palpable breast lesions seen on mammograms. Twenty-five cases were densities, architectural distortions or radial scars, and 42 were microcalcifications. RESULTS: In our hands, the technique is 100% specific and sensitive. This high percentage of success is related to a team work between radiologists, surgeons or gynecologists. The specimen represent the whole lesion. Ductal carcinoma in situ (DCIS) and atypic ductal hyperplasia (ADH) are diagnosed with accuracy. Twelve carcinomas are found, three of them DCIS. ADH was encountered in two cases. Complications are minor, hematomas of small and moderate volume were encountered in eight cases (12%). CONCLUSION: ABBI technique replaces surgical biopsies after wire hook localisation for solitary lesion smaller than two cm in diameter; and stereotactic Tru-cut biopsies, even with vacuum aspiration, for small cluster of microcalcifications, architectural distortion and radial scar, where the percentage of failure is higher. For malignant lesions, surgery must follow, even when the margins are free.

Adult↗
PubMedDate not supplied

[Echocardiography in the evaluation and pre- and postoperative follow-up of chronic aortic insufficiency].

In chronic aortic regurgitation (CAoR) is difficult to determine the moment in which volume overload produces the myocardial deterioration which originates symptoms. We pretend to demonstrate the utility of echocardiography in defining the correct timing of operative correction in CAoR with pre- and post-operative comparison. Thirteen patients with CAoR (systolic ventricular-aortic gradient less than 20 mmHg) in whom the aortic valve was replaced were studied with an average of 13.7 months of follow-up. Two patients died immediately after surgery. Those remaining had a decrease in cardiomegaly grade and moved into functional class I. The echocardiogram revealed a significant reduction (P less than 0.01) in diameters of the left ventricle. The ejection fraction increased (P less than 0.05) in the post-operative period. Fractional shortening (FS) and mean velocity of circumferential shortening showed no significant change. The index end-systolic diameter over normalized velocity of the posterior wall IESD/NVPW) decreased considerably and the mean velocity of circumferential relaxation (Vcfr) increased (P less than 0.001) after surgical treatment. The preoperative ESD/NVPW index and Vcfr correlated well with the left ventricular end-diastolic pressure (r = 0.891 and r = -0.885, respectively). There was no difference in the course of those patients with diminished FS. The ESD/NVPW index and the Vcfr allowed a better evaluation of the residual volume, of the Frank-Starling law and of distensibility as an expression of the ventricular function. Consequently we conclude these indices are useful to establish the best moment for pre-operative catheterization in patients with CAoR.

Adolescent↗
PubMedDate not supplied

[Infectious endocarditis in children].

he recent advances in surgical treatment of congenital heart disease, permits the survival of those cases to adult life. Infective endocarditis in the childhood is becoming increasingly important. We studied 32 cases in the pediatric cardiology ward at the INC between 1977 and 1981. There was a male predominance of 62.5%. Rheumatic heart disease (40.7%), congenital heart disease (15.6%) and postoperative cases (43.7%) were the underlying conditions. There was an average time of 43 days delay from the first symptom to diagnosis. Blood cultures were taken in 29 cases (90.6%). Only half of them were positive. Staphylococcus and streptococcus were the commonest isolates. Peripheral and pulmonary embolism (11 cases-34.4%) were the most frequent complications. In those cases with negative blood culture the most successful antibiotic combination was ampicillin or oxacillin plus aminoglucosides (56%). There were 17 deaths (53%).

Adolescent↗