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Biomedical subjects

M R Essop

Publications and source records attributed to M R Essop.

27 records · Page 2Linked to original sources
PubMed1993

Frequency and severity of intravascular hemolysis after left-sided cardiac valve replacement with Medtronic Hall and St. Jude Medical prostheses, and influence of prosthetic type, position, size and number.

Intravascular hemolysis occurs often in patients with mechanical heart valve prostheses, but in most cases is of mild degree and subclinical. The severity of hemolysis is reported to be related to the type, position and size of prostheses used, as well as the presence of valve malfunction. Hemolysis was evaluated in 170 patients with St. Jude Medical (SJM) and 80 patients with Medtronic Hall (MH) prostheses, with normal mechanical function. The presence and severity of hemolysis was assessed on the basis of serum lactic dehydrogenase, serum haptoglobin, blood hemoglobin and reticulocyte levels as well as the presence of schistocytes. Overall, patients with SJM prostheses had greater frequency (51.2 vs 18.7%, p < 0.005) and severity (p < 0.005) of hemolysis than patients with MH prostheses, irrespective of position and size. No patient had decompensated anemia. The frequency of hemolysis was similar in both groups with double-valve replacement, whereas severity was greater with SJM than MH prostheses (p < 0.001). The number and position of the prostheses were correlated with severity of hemolysis: Double-valve replacement and mitral position were correlated with greater hemolysis than single-valve replacement (p < 0.01) and aortic position (p < 0.01). Valve size, cardiac rhythm and time from operation did not correlate either with frequency or severity of hemolysis. It is concluded that in normally functioning SJM and MH prostheses: (1) hemolysis is frequent but never severe; (2) SJM demonstrates greater frequency and severity when compared with MH valve; and (3) number, position, but not size, significantly affect the severity of hemolysis.

Adult↗
PubMed1993

Evidence against a myocardial factor as the cause of left ventricular dilation in active rheumatic carditis.

OBJECTIVES: The aim of this study was to determine whether left ventricular dilation and congestive heart failure in patients with acute rheumatic fever with carditis are accompanied by left ventricular contractile dysfunction. BACKGROUND: Acute rheumatic fever with carditis involves both the myocardium and endocardium, with consequent valvular regurgitation. The relative contribution of volume overload induced by valvular regurgitation and myocardial dysfunction due to rheumatic myocarditis to the overall degree of left ventricular dilation and congestive heart failure in these patients is unknown. METHODS: To investigate this, we evaluated 32 patients (15 male, 17 female, mean age 14 +/- 3 years) with documented active carditis and congestive heart failure. All 32 patients were found to have significant isolated mitral regurgitation or combined mitral and aortic regurgitation. Echocardiographic analysis of left ventricular dimensions and systolic performance was performed before and after isolated mitral or combined mitral and aortic valve replacement and the results were compared with those in 19 control subjects matched for age, gender and body surface area. RESULTS: Both preoperative left ventricular end-diastolic diameter and percent fractional shortening were significantly increased in patients compared with control subjects (57 +/- 7 vs. 43 +/- 3 mm, p < 0.001, and 38 +/- 6% vs. 33 +/- 1%, p < 0.001, respectively). After valve replacement, left ventricular end-diastolic diameter decreased significantly (57 +/- 7 to 47 +/- 6 mm, p < 0.001). Although percent fractional shortening decreased significantly postoperatively (38 +/- 6% to 32 +/- 6%, p < 0.001), the postoperative percent fractional shortening did not differ from that in control subjects (32 +/- 6% vs. 33 +/- 1%, p = NS). CONCLUSIONS: The results of this study indicate that left ventricular dilation and heart failure in patients with acute rheumatic carditis rarely occur in the absence of hemodynamically significant regurgitant valve lesions. Furthermore, rapid reduction in left ventricular dimensions and preservation of fractional shortening after isolated mitral or combined mitral and aortic valve replacement suggest that rheumatic carditis is not accompanied by any significant degree of myocardial contractile dysfunction.

Adolescent↗
PubMed1993

Angioplasty for treatment of Takayasu's arteriopathy: case reports.

Two cases of Takayasu's arteritis with severe renovascular hypertension are described. Both patients underwent successful percutaneous balloon angioplasty with attenuation of the systemic hypertensive response. The role of angioplasty as an alternative to surgery for revascularization of symptomatic ischemia in this disease is reviewed.

Adult↗
PubMed1992

Effects of long-acting nifedipine on casual office blood pressure measurements, 24-hour ambulatory blood pressure profiles, exercise parameters and left ventricular mass and function in black patients with mild to moderate systemic hypertension.

Thirty-nine black patients with mild to moderate hypertension were treated for 1 year with various long-acting preparations of nifedipine, during which time serial changes in 24-hour ambulatory blood pressure (BP), exercise performance, left ventricular (LV) mass index and LV systolic function were evaluated. Mean 24-hour ambulatory BP decreased from 156 +/- 15/99 +/- 8 to 125 +/- 10/79 +/- 6 mm Hg at 1 year (p less than 0.0001). LV mass index decreased from 130 +/- 40 to 114 +/- 39 g/m2 at 6 weeks (p less than 0.005) and to 95 +/- 32 at 1 year (p less than 0.0001). There was a significant reduction in septal and posterior wall thickness from 11.0 +/- 2.0 to 9.3 +/- 2.0 mm (p less than 0.0001) and from 10.9 +/- 2.0 to 9.3 +/- 2.0 mm (p less than 0.005), respectively. Cardiac index and fractional shortening changed insignificantly from 2.9 +/- 0.7 to 2.9 +/- 0.6 liters/min/m2, and from 35 +/- 5 to 36 +/- 6%, respectively. At 1 year, using a modified Bruce protocol, exercise time increased from 691 +/- 138 to 845 +/- 183 seconds (p less than 0.05); peak exercise and 1 minute post-effort systolic BP decreased from 240 +/- 26 to 200 +/- 21 mm Hg and from 221 +/- 27 to 169 +/- 32 mm Hg (p less than 0.05), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Arterial phase left atrial opacification in acute massive pulmonary embolism.

Classic angiographic features in acute massive pulmonary embolism include main or lobar arterial branch cut-off, and/or arterial filling defects with matching impaired venous drainage. Six haemodynamically compromised patients with acute massive pulmonary embolism (mean pulmonary artery pressure 55 +/- 12 mmHg), confirmed by pulmonary arteriography, are described. Early opacification of the left atrium during the arterial phase of the pulmonary angiogram was seen in all patients. Follow-up pulmonary arteriography after successful thrombolytic therapy was performed 4 days later in 2 cases. A marked haemodynamic improvement was accompanied by resolution of the previous abnormal angiographic signs, including early opacification of the left atrium. The latter might be a response to intensive reactive vasodilatation of the remaining perfused lung fields resulting in a more rapid pulmonary transit time and the opening of arteriovenous channels with further systemic desaturation. This angiographic sign is a marker of severe, but reversible, vasoconstriction in acute massive pulmonary embolism.

Acute Disease↗
PubMed1991

Mitral regurgitation following mitral balloon valvotomy. Differing mechanisms for severe versus mild-to-moderate lesions.

BACKGROUND: This study was designed to evaluate the incidence and mechanisms of mitral regurgitation following mitral balloon valvotomy (MBV) in 40 consecutive patients with symptomatic tight pliable mitral stenosis. METHODS AND RESULTS: Transthoracic echocardiography with color flow mapping was performed before and 24 hours after the procedure. Patients who developed significant mitral regurgitation following MBV also underwent transesophageal echocardiography. The relation between increased mitral regurgitation and both valvular morphology and procedure-related factors was examined. Gorlin mitral valve area increased from 0.81 +/- 0.3 to 1.95 +/- 0.7 cm2 (p less than 0.001). No patient had more than 2+ mitral regurgitation by angiography and color Doppler prior to MBV. There was a moderate correlation between Doppler and angiographic increase in mitral regurgitation (r = 0.73, p less than 0.0001). By Doppler criteria 33 patients had no (n = 6) or mild (n = 27) increase in mitral regurgitation (group 1), and seven developed significant new mitral regurgitation (group 2). Baseline clinical, echocardiographic, and procedure-related data for the two groups were similar. Multiple regression analysis did not select any individual valve characteristic (valvular thickening, mobility, calcification, and subvalvular disease), total echocardiographic score, balloon diameter, or ratio of balloon to mitral annular diameter as disruption with a torn anterior or posterior mitral leaflet in six and a ruptured papillary muscle in one. Two of these patients have required mitral valve replacement (6 and 9 months following the procedure), whereas the remainder are significantly symptomatic. By contrast, mitral regurgitation in group 1 either occurred at the site of commissural split (n = 20) or was associated with prolapse of the anterior mitral leaflet (n = 6). CONCLUSIONS: Thus, severe new mitral regurgitation following MBV is due to noncommissural tearing of the mitral leaflet and confers an adverse long-term prognosis. A mild increase in mitral regurgitation following MBV is frequent and occurs at the site of commissural split or is associated with prolapse of the anterior leaflet. Furthermore, in this study, an increase in mitral regurgitation could not be predicted from any valvular or procedure-related factor.

Adult↗