W. Allan Edmiston

Effect of partial ileal bypass surgery on mortality and morbidity from coronary heart disease in patients with hypercholesterolemia: Report of the program on the surgical control of the hyperlipidemias (posch)

BACKGROUND AND METHODS The Program on the Surgical Control of the Hyperlipidemias (POSCH), a randomized clinical trial, was designed to test whether cholesterol lowering induced by the partial ileal bypass operation would favorably affect overall mortality or mortality due to coronary heart disease. The study population consisted of 838 patients (417 in the control group and 421 in the surgery group), both men (90.7 percent) and women, with an average age of 51 years, who had survived a first myocardial infarction. The mean follow-up period was 9.7 years. RESULTS When compared with the control group at five years, the surgery group had a total plasma cholesterol level 23.3 percent lower (4.71 +/- 0.91 vs. 6.14 +/- 0.89 mmol per liter [mean +/- SD]; P less than 0.0001), a low-density lipoprotein cholesterol level 37.7 percent lower (2.68 +/- 0.78 vs. 4.30 +/- 0.89 mmol per liter; P less than 0.0001), and a high-density lipoprotein cholesterol level 4.3 percent higher (1.08 +/- 0.26 vs. 1.04 +/- 0.25 mmol per liter; P = 0.02). Overall mortality and mortality due to coronary heart disease were reduced, but not significantly so (deaths overall [control vs. surgery], 62 vs. 49, P = 0.164; deaths due to coronary disease, 44 vs. 32, P = 0.113). The overall mortality in the surgery subgroup with an ejection fraction greater than or equal to 50 percent was 36 percent lower (control vs. surgery, 39 vs. 24; P = 0.021). The value for two end points combined--death due to coronary heart disease and confirmed nonfatal myocardial infarction--was 35 percent lower in the surgery group (125 vs. 82 events; P less than 0.001). During follow-up, 137 control-group and 52 surgery-group patients underwent coronary-artery bypass grafting (P less than 0.0001). A comparison of base-line coronary arteriograms with those obtained at 3, 5, 7, and 10 years consistently showed less disease progression in the surgery group (P less than 0.001). The most common side effect of partial ileal bypass was diarrhea; others included occasional kidney stones, gallstones, and intestinal obstruction. CONCLUSIONS Partial ileal bypass produces sustained improvement in the blood lipid patterns of patients who have had a myocardial infarction and reduces their subsequent morbidity due to coronary heart disease. The role of this procedure in the management of hypercholesterolemia remains to be determined. These results provide strong evidence supporting the beneficial effects of lipid modification in the reduction of atherosclerosis progression.

Flow characteristics of four commonly used mechanical heart valves

The in vivo and in vitro fluid dynamic performance of 4 mechanical heart valves was reviewed: Starr-Edwards silicon-rubber ball valves (models 1200/1260 aortic and 6120 mitral valves), Björk-Shiley tilting disc valves (standard spherical model, modified and unmodified convexo-concave [60 degrees and 70 degrees C-C] models), the Medtronic-Hall (Hall-Kaster) tilting disc valve and the St. Jude Medical bileaflet valve. These valves were chosen because of their past or present popularity in clinical use and because they encompass most of the basic mechanical valve designs used during the past 2 decades. The flow measurements reported include in vivo and in vitro mean pressure drop, cardiac output or cardiac index, regurgitant volume, effective orifice area and performance index.

Cholelithiasis: A frequent complication of artificial heart valve replacement

The results of this investigation reveal that 39 per cent of patients in a study group of 46 patients with heart valve prostheses had gallstones if they survived 18 months or longer following valve replacement. In contrast, the prevalence of gallstones in a general population of autopsied rheumatic heart disease patients, including those who had been operated for severe valvular heart disease and had not survived for more than one month, was only 12 per cent. These findings suggest that gallstones are a frequent late complication of heart valve replacement.

Mitral E point septal separation: A reliable index of left ventricular performance in coronary artery disease

The diagnostic value of E point septal separation (EPSS) was assessed in 108 patients with coronary artery disease who underwent coronary angiography and M-mode echocardiography within a 2-year period at LAC/USC Medical Center. In patients with anterior myocardial infarction, EPSS correlated well with angiographic ejection fraction, with a specificity of 85% and sensitivity of 82%. In inferior myocardial infarction, a 21% frequency of falsely elevated EPSS values was encountered; the sensitivity for detecting reduced ejection fraction was 100% and the specificity was 67%. In combined anterior and inferior myocardial infarction, EPSS accurately estimated abnormal ejection fractions with a sensitivity and specificity of 100%. An abnormal EPSS (more than 7 mm) was found to be more sensitive (87%) and specific (75%) in detecting individuals with angiographically reduced ejection fraction (less than 50%) compared to other echocardiographic indices of pump function. Importantly, EPSS was effective in estimating left ventricular function in the presence of left bundle branch block, paradoxical septal motion, and angiographic septal, posterior, and anterior wall motion abnormalities.

Thromboembolism in mitral porcine valve recipients.

A low incidence rate of thromboembolism has been reported in mitral porcine valve recipients. In contrast, 5 of 22 single mitral porcine valve recipients (23 percent) followed up in our clinic for a mean of 16 months had thromboembolic events. All patients but one were receiving long-term anticoagulant therapy. One thromboembolic event resulted in death, three in permanent neurologic deficits and one in a peripheral arterial occlusion. All five patients with emboli had atrial fibrillation and left atrial enlargement. Three had thromboembolic events before porcine heart valve implantation. In addition, five mitral porcine valve recipients who were not receiving anticoagulant therapy were examined at autopsy. Thrombus was identified in the left atrium in three patients, at the tissue-valve interface (sewing ring) in two, on the porcine valve cusps in one and in the right atrium in one. Factors influencing thrombus formation such as left atrial enlargement, atrial fibrillation and a prosthetic device are present after mitral porcine valve implantation and are indications for long-term anticoagulation therapy.

Problems in ultrasonic estimates of septal thickness

Problems related to cardiac anatomy and ultrasonic instrumentation affect the accuracy of echographic identification of endocardial echoes. A cadaver model and 13 patients were studied, with direct identification or with the aid of echographic contrast techniques, to identify accurately the endocardial echo. The study showed that (1) echographic contrast agents delineate an endocardial echo in the central portion of the ultransonic beam; (2) a specular reflector exists within the right ventricular cavity; (3) specular reflectors within the septum may give the false appearance of border-forming echoes; (4) septal thickness varies by 1 to 5 mm after the endocardial echo has been identified by the contrast agent; and (5) spurious echoes, related to a wide beam angle, can be confused with the endocardial echo. In light of these problems, three criteria were utilized for endocardial echo identification: the prominent notch in the left septal echo, the specular quality of the right septal echo, and the association of multiple myocardial echoes moving in parallel. With these criteria, the endocardial echoes in 11 of the 13 patients could be accurately identified without the use of a contrast agent. The identification of these problems should provide helpful guidelines in developing more accurate and reproducible criteria for septal thickness measurements.

Program on the surgical control of the hyperlipidemias (POSCH): Patient entry characteristics

The entry characteristics of patients in the Program on the Surgical Control of the Hyperlipidemias (POSCH), a randomized, controlled, clinical trial, are described in this article. The primary objective addressed by POSCH was whether lowering total plasma cholesterol by partial ileal bypass surgery results in a reduction in mortality and morbidity in post-myocardial infarction patients. Between 1975 and 1983, 838 patients between the ages of 30 and 64 years were randomized into POSCH. The mean age at entry was 51 years, and 91% of the patients were men. The mean time between myocardial infarction and entry was 2.2 years. The mean baseline total plasma cholesterol was 251 mg/dl, with a mean LDL-cholesterol of 179 mg/dl and a mean HDL-cholesterol of 40 mg/dl. Significant disease (greater than or equal to 50% occlusion) of one or more major coronary arteries was found in 91% of the patients. In addition to a description of the POSCH patient population at entry, comparisons of the POSCH patient population to populations of participants in other lipid-lowering trials are presented to provide a perspective on how POSCH relates to these trials.

Clinical Experience With the Smeloff-Cutter Aortic Valve Prosthesis: An 8-Year Follow-Up Study

A total of 46 patients who survived aortic valve replacement with the present model Smeloff-Cutter prosthesis between 1968 and 1973 were followed up postoperatively. All patients received oral anticoagulant therapy. The average age at implantation was 44 +/- 13 (mean +/- standard deviation) years; 36 patients were male and 10 were female. The valve damage was caused by rheumatic disease in 19 (41 percent), infective endocarditis in 14 (30 percent), congenital heart disease in 7 (15 percent) and other factors in 6 (13 percent). Late death occurred in eight patients (17 percent). All available patients were followed up until December 1976. During the 8 years of follow-up study, seven patients, including four heroin addicts, had postoperative endocarditis (15 percent); five of the seven had cerebral involvement, possibly from septic emboli. Four patients were reoperated on; three had active endocarditis and one had a high transvalve pressure gradient. The mean follow-up time was 4.9 years per patient. Of the 38 living patients, 33 have functional improvement and are still being followed up. Only one patient had a bland embolism to a systemic artery. No ball variance or other types of material failure have been detected. Although the chronic aspects of valve disease remain after prosthetic valve replacement, the Smeloff-Cutter aortic prosthesis deserves strong consideration when selecting a rigid prosthesis for aortic valve replacement.

Efficacy of bucindolol in systemic hypertension

The hemodynamic effects of oral bucindolol, a non-selective beta-adrenergic blocking agent with intrinsic sympathomimetic activity and direct vasodilating properties, were studied at rest and during handgrip exercise with a flotation-directed pulmonary artery catheter in 12 patients with mild to moderate essential hypertension. After the initial dose of 150 mg of bucindolol, blood pressure (BP) was significantly reduced and cardiac output was increased (from 5.9 +/- 0.8 to 6.8 +/- 1.6 liters/min) in the supine position and during exercise (p less than 0.05). Systemic vascular resistance was reduced (from 1,555 +/- 339 to 1,311 +/- 467 dynes s cm-5, p less than 0.01) at rest and without significant changes during exercise. There were increases in heart rate (13 +/- 13%, p less than 0.01) and right atrial (69 +/- 77%, p less than 0.05), pulmonary arterial (38 +/- 24 %, p less than 0.001) and pulmonary artery wedge pressures (62 +/- 46%, p less than 0.001) during exercise. Bucindolol did not change these variables at rest or during exercise. Bucindolol increased plasma norepinephrine levels both at rest (from 330 +/- 151 to 588 +/- 320 ng/liter, p less than 0.01) and during exercise (from 468 +/- 220 to 685 +/- 390 ng/liter, p less than 0.05). After 4 weeks of bucindolol with doses of 50 to 200 mg 3 times daily, BP was reduced in both supine and standing positions (mean arterial BP of 11 +/- 7% [p less than 0.001] and 11 +/- 6% [p less than 0.001], respectively), without changes in cardiac output, systemic vascular resistance or plasma norepinephrine level.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum enzyme changes after cardiac catheterization and angiographic procedures.

From the Department of Internal Medicine, Cardiology Section, Los Angeles County-University of Southern California Medical Center, Los Angeles, California. Mr. Takiff is a student research associate of the American Heart Association, California Affiliate. Elevations of the &dquo;cardiac enzymes&dquo; creatine phosphokinase (CPK), lactate dehydrogenase (LDH), and serum glutamic oxaloacetic transaminase (SGOT)