Search PubMed⌕ Search

Biomedical subjects

R C Pasternak

Publications and source records attributed to R C Pasternak.

At least 55 records · Page 3Linked to original sources
PubMed1990

Effects of two types of fish oil supplements on serum lipids and plasma phospholipid fatty acids in coronary artery disease.

Fish oil has consistently been shown to lower triglyceride levels, but its effects on low-density lipoprotein (LDL) cholesterol remain controversial. The current study compares the long-term effects of 2 different fish oil preparations (ethyl ester and triglyceride) versus olive oil in patients with coronary artery disease. Eighty-nine subjects were randomly assigned to receive capsules containing 6 g/day (triglyceride group) or 7 g/day (ethyl ester group) of n-3 fatty acids, or capsules containing 12 g/day of olive oil for 6 months. Mean triglyceride levels decreased by 28% in the ester and 32% in the triglyceride fish oil groups (p less than 0.05 for both). LDL cholesterol levels increased by 3% (difference not significant) in the ester and 12% (p less than 0.05) in the triglyceride fish oil groups; in hypertriglyceridemic subjects the increase was 23% (p less than 0.01) and 14% (difference not significant), respectively. Plasma phospholipid fatty acid analysis showed a fivefold increase in eicosapentaenoic acid levels in both fish oil groups (p less than 0.001), and a long-term decrease in arachidonic acid levels (p less than 0.001). Achieved eicosapentaenoic acid level correlated with the degree of increase in LDL cholesterol (r = 0.38, p less than 0.05). These data suggest that fish oil administration is associated with an increase in LDL cholesterol levels in a diverse group of patients with coronary artery disease; this change appears to be correlated with n-3 fatty acid absorption. The impact of this increase in LDL is unknown, but should be considered as potentially adverse.

Coronary Disease↗
PubMed1989

Effect of a modified, well-tolerated niacin regimen on serum total cholesterol, high density lipoprotein cholesterol and the cholesterol to high density lipoprotein ratio.

One hundred one patients with coronary artery disease and pretreatment ratios of total cholesterol to high density lipoprotein (HDL) cholesterol greater than 4.0 were treated with niacin, commencing at low dosages (100 to 250 mg twice daily) and gradually increasing the dosage over 4 to 8 weeks to 1,000 mg twice daily. Dosage adjustments were made to minimize side effects. At a mean follow-up duration of 11 +/- 7 months, and a mean dosage of 1,415 +/- 698 mg/day, the group had a 13% reduction in total cholesterol, 31% increase in HDL and 32% decrease in the cholesterol to HDL ratio. A subgroup of 62 patients taking greater than 1,000 mg/day of niacin had an 18% reduction in total cholesterol, 32% increase in HDL and 36% improvement in the cholesterol to HDL ratio. A subgroup of 39 patients taking less than or equal to 1,000 mg/day of niacin had only a 5% reduction in total cholesterol, although a 29% increase in HDL and a 24% decrease in the cholesterol to HDL ratio were recorded. Side effects of niacin were reported in 38% of the patients, but led to discontinuation of therapy in only 4. Niacin can be administered in a fashion that is well tolerated, inexpensive and very effective in improving the cholesterol to HDL ratio.

Adult↗
PubMed1989

Significance of nitroglycerin-induced hypotension with inferior wall acute myocardial infarction.

Up to 60% of patients with inferior wall acute myocardial infarction (AMI) develop hypotension. In many cases, profound hypotension is precipitated by the administration of nitroglycerin. To test the hypothesis that this hypotensive response to nitroglycerin may be related to right ventricular (RV) involvement, we compared 20 patients with electrocardiographic and enzyme-documented inferior wall AMI and marked hypotension (greater than 30 mm Hg decrease in systolic blood pressure, with symptoms) after nitrate administration, to 20 patients with documented inferior AMI, but without hypotension after administration of nitroglycerin. The presence of RV involvement was determined by electrocardiographic criteria of 1 mm of ST-segment elevation in at least 2 right precordial chest leads. Fifteen of the 20 patients who demonstrated a marked hypotensive response to nitroglycerin had evidence of RV involvement, while in 18 of the 20 patients without hypotension after nitrates there was no evidence of RV involvement. In a separate analysis of 28 patients with documented RV involvement in an inferior AMI, 20 developed hypotension in response to nitrates. Thus, in the setting of an inferior AMI, a marked hypotensive response to nitrates suggests the presence of RV involvement. Moreover, hypotension after nitrate administration may be anticipated in patients with known RV infarction, and in such patients, nitrates should be administered carefully.

Cardiac Output↗
PubMed1989

Randomised trial of fish oil for prevention of restenosis after coronary angioplasty.

To examine the potential role of fish oil supplementation in the prevention of restenosis after coronary angioplasty (PTCA), a randomised double-blind trial was conducted in 204 patients. The treatment group received 6 g/day of n-3 fatty acids, beginning 5.4 (SD 3.2) days before PTCA, and continuing for 6 months; the control group received olive oil placebo. Compliance was assessed by pill count and plasma levels of eicosapentaenoic acid (EPA). Restenosis was identified by symptoms and exercise testing and confirmed by angiography. PTCA was successful in 186 patients (93%). The incidence of angiographic restenosis was 34% in the fish oil group and 23% in the control group (relative risk 1.7, 95% CI 0.9-3.4). The lack of benefit of fish oil was not influenced by length of pretreatment, compliance with study medication, or the concentrations of plasma EPA achieved.

Angioplasty, Balloon↗
PubMed1988

Usefulness of lactate dehydrogenase and lactate dehydrogenase isoenzymes for diagnosis of acute myocardial infarction.

The usefulness of lactate dehydrogenase (LD) and LD isoenzymes in the diagnosis of acute myocardial infarction (AMI) is controversial. The present study reviewed 507 consecutive patients in whom creatine kinase, creatine kinase isoenzymes, LD and LD isoenzymes were ordered over a 1-month period. Of these, 249 had an insufficient number of serial enzyme determinations to establish a laboratory diagnosis of AMI. After excluding an additional 11 patients for other reasons, 247 patients remained for analysis. Of these, only 2 (0.8%) had myocardial infarction by standard clinical criteria with normal creatine kinase and creatine kinase-MB but elevated LD and abnormal LD isoenzymes. Seven patients (7 of 247, 2.8%) had false-positive LD isoenzymes. Thus, the routine use of LD and LD isoenzymes was of no use in most patients (96%) and led to the incorrect diagnosis of AMI more than 3 times as often as it helped with a correct diagnosis. Total 1-month charges for all the LD and LD isoenzymes obtained equalled +42,450. Therefore, it appears that LD and LD isoenzymes are not routinely useful in the diagnosis of AMI and may result in considerable unnecessary expense. It is suggested that LD and LD isoenzymes be ordered only under suspicion of late presentation (greater than 48 hours) of AMI.

Creatine Kinase↗
PubMed1988

Hemodynamic responses to noninvasive external cardiac pacing.

Although improvements in noninvasive external cardiac pacing have led to a technique with reliable electrical capture and reduced patient discomfort, hemodynamic responses to this pacing mode have not been described previously. Accordingly, this technique was applied to 16 patients with a clinical diagnosis of angina pectoris undergoing cardiac catheterization. Three patients had normal coronary arteries, whereas the remaining 13 had significant coronary artery disease. All patients had noninvasive pacing at increasing heart rates to 85 percent of age-predicted maximal heart rate. At maximal pacing, all patients demonstrated a rise in atrial, pulmonary artery, and mean aortic pressures. Cardiac index remained unchanged, reflecting parallel increases in arteriovenous oxygen difference and oxygen consumption. One minute after cessation of pacing, pulmonary artery pressure and oxygen consumption remained elevated, whereas arteriovenous oxygen difference returned to baseline with a subsequent rise in cardiac index. Angina occurred in eight patients with coronary artery disease at peak pacing and was accompanied by a rise in left ventricular end-diastolic pressure after pacing. In eight patients without pacing-induced angina, including the three patients with normal coronary arteries, there was no significant change in left ventricular end-diastolic pressure after pacing. It is concluded that noninvasive external cardiac pacing produces a rise in both right and left heart filling pressures and in oxygen consumption that persist after pacing, and may provoke angina and hemodynamic abnormalities consistent with myocardial ischemia. This mode of pacing appears hemodynamically safe with maintenance of cardiac index and aortic pressure at 85 percent of maximal age-predicted heart rate.

Angina Pectoris↗
PubMed1987

Need for better severity indexes of acute myocardial infarction under diagnosis-related groups.

Clinical, demographic and administrative data, including length of stay and institutional charges, were examined for 219 patients hospitalized for acute myocardial infarction (AMI). Neither length of stay nor charges differed among AMI patients with or without cardiovascular complications as defined by Medicare's diagnosis-related group (DRG) categories (DRG 121 and 122, respectively) for patients who are discharged alive. Myocardial enzyme peak levels are the best predictors of hospital resource consumption for patients with AMI when considered alone or in combination with other factors. The "cardiovascular complications" designated by discharge diagnoses did not reflect resource consumption in our patient population. Sixteen percent of the patients studied underwent cardiac catheterization during hospitalization. These patients stayed in the hospital longer and incurred 70% higher charges; nevertheless, they were grouped with the remaining AMI patients in the current DRG formulation. Clinical evaluations such as cardiovascular complications are subject to interpretation, and are therefore less credible than enzyme measurements for recognizing the severity of a patient's AMI. Reimbursement based on objective measurements may avoid payment inequities.

Aged↗
PubMed1987

Usefulness of percutaneous transluminal coronary angioplasty for unstable angina pectoris after non-Q-wave acute myocardial infarction.

Without revascularization, patients with non-Q-wave acute myocardial infarction (AMI) are predisposed to angina, recurrent AMI and cardiac death. Percutaneous transluminal coronary angioplasty (PTCA) was performed in 68 patients with angina an average of 2.3 months after non-Q-wave AMI (41 anterior, 27 inferior). Mean diameter stenosis was 95%, with collateralized total occlusion of the infarct-related artery in 23 patients. PTCA was successful in 87% (59 of 68), with a mean residual stenosis of 30%. One patient had emergency bypass surgery. Long-term follow-up (average 17 +/- 10 months) was available for 58 of the 59 patients in whom PTCA was successful. Recurrent angina developed in 41% (24 of 58), but was relieved by repeat PTCA in 14, by late coronary artery bypass surgery in 4 and by medical therapy in 6. There was 1 nonfatal AMI, due to progressive disease in a nondilated vessel, and 1 noncardiac death At last follow-up, 46 of 58 patients (79%) were asymptomatic and fully active or employed. Thus, patients undergoing PTCA for angina after non-Q-wave AMI appear to have a relatively high clinical restenosis rate, but with repeat PTCA have a low incidence of subsequent angina, AMI and cardiac death.

Adult↗
PubMed1987

Incidence and management of limb ischemia with percutaneous wire-guided intraaortic balloon catheters.

In 103 patients who underwent placement of 106 percutaneous wire-guided intraaortic balloon catheters between August 1983 and January 1986, all placements were successful and the average duration of counterpulsation was 3.4 +/- 1.6 days. During counterpulsation, 45 patients developed limb ischemia that required premature balloon removal in 29 patients. The development of limb ischemia was significantly related to the presence of diabetes (risk ratio 2.0), peripheral vascular disease (risk ratio 1.9), female gender (risk ratio 1.8) and the presence of a postinsertion ankle-brachial pressure index less than 0.8 (risk ratio 7.9). There was no association between the development of limb ischemia and age, body surface area, balloon size (10.5F/12F) or adequacy of anticoagulation. Fifteen patients underwent vascular surgery for treatment of balloon-related limb ischemia, which was associated with one operative death. Nine patients had persistent limb ischemia (seven asymptomatic, two symptomatic) at the time of hospital discharge. Improvements in wire-guided balloon technology have increased the probability of successful balloon placement over that of surgical placement and have reduced the incidence of major aortic injury, but there is no evidence that these improvements have reduced the incidence of limb ischemia or its sequelae. This should be borne in mind before proceeding with balloon insertion in patients with one or more risk factors for developing limb ischemia.

Aged↗
PubMed1986

Elevated CK-MB with normal total creatine kinase in suspected myocardial infarction: associated clinical findings and early prognosis.

To test the hypothesis that patients with normal serum levels of creatine kinase (CK) but elevated percentages of MB isoenzyme fractions in suspected myocardial infarction may have sustained clinically significant events, we studied the hospital course of 347 consecutive patients admitted with suspected myocardial infarction. Two hundred twenty-three patients had normal CK levels (182 +/- 44 IU) and normal MB percentages (normal group), 68 had elevated levels of both CK (1395 +/- 178 IU) and MB percentage (10.5 +/- 0.6) (macroinfarction group), and 40 had normal CK levels (96 +/- 7 IU) but elevated MB percentages (9.6 +/- 0.5) with typical enzyme curves (microinfarction group). Compared to the normal group, microinfarction patients were older, had more congestive heart failure, required more intensive monitoring and therapy during longer stays, and sustained a higher in-hospital mortality rate. Thus, these microinfarction patients are at increased risk and therefore warrant aggressive treatment and further evaluation.

Acute Disease↗
PubMed1986

Assessment of left ventricular end-systolic pressure-volume relations with an impedance catheter and transient inferior vena cava occlusion: use of this system in the evaluation of the cardiotonic effects of dobutamine, milrinone, Posicor and epinephrine.

The end-systolic pressure-volume relation has been postulated as a load-independent measure of cardiac contractility, but has been difficult to measure because of technical problems associated with the serial measurement of intracardiac volume over a physiologic range of ventricular loading conditions. Utilizing a multielectrode impedance catheter to assess continuous, on-line left ventricular relative volume during transient inferior vena cava occlusion, a method is described for determining the end-systolic pressure-volume relation and for assessing changes in this relation secondary to inotropic modulation. In particular, using this method, the relative inotropic properties were determined of four drugs: dobutamine, milrinone, epinephrine and an experimental cardiotonic agent (Ro 13-6438, Posicor). Left ventricular micromanometer pressure and impedance catheter volume were measured continuously in 10 open chest, anesthetized dogs and 14 pigs. Arterial pressure was altered over a range of 20 to 60 mm Hg by brief inferior vena cava constriction. A linear end-systolic pressure-volume relation was observed in pressure-volume diagrams constructed from on-line pressure and impedance catheter recordings. Administration of dobutamine, milrinone and epinephrine resulted in a leftward shift and an increase in the slope of the end-systolic pressure-volume relation as compared with baseline; Posicor did not alter the slope over a range of doses, despite an increase in the cardiac output secondary to arterial vasodilation. Volume changes as measured by the impedance method closely paralleled simultaneous changes in the ultrasonic crystal-determined segment length, and the impedance end-systolic pressure-volume relation slope was reproducible with repeated load-altering maneuvers.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Left ventricular remodeling after myocardial infarction: a corollary to infarct expansion.

Dilatation of infarcted segments (infarct expansion) may occur during recovery from myocardial infarction, but the fate of noninfarcted segments is uncertain. Accordingly, left ventricular geometric changes were assessed by left ventricular angiography and M mode echocardiography on admission and 2 weeks later in 30 patients with their first acute transmural myocardial infarction. All patients demonstrated chest pain, ST segment elevation with subsequent development of Q waves (15 anterior, 15 inferior), and elevation of cardiac enzymes. Sequential left ventricular angiographic and hemodynamic findings were available in these patients by virtue of their participation in a study of thrombolysis in acute myocardial infarction. By that study design, all patients treated successfully with thrombolytic therapy and demonstrating improvement of flow in an occluded coronary artery underwent repeat cardiac catheterization. At 2 weeks there was a significant decrease in left ventricular and pulmonary capillary wedge pressures (p less than .01), whereas both left ventricular end-diastolic (LVEDV) and end-systolic (LVESV) volume indexes increased (p less than .01). The increase in LVEDV correlated directly with the percentage of the ventriculographic silhouette that was akinetic or dyskinetic at the initial catheterization (r = .71, p less than .001). To assess regional changes in both infarcted and noninfarcted segments, serial endocardial perimeter lengths of both the akinetic-dyskinetic segments (infarction zone) and of the remainder of the cardiac silhouette (noninfarction zone) were measured in all patients who demonstrated at least a 20% increase in their LVEDV at 2 weeks after myocardial infarction. Notably, there was a mean increase of 13% in the endocardial perimeter length of infarcted segments and a 19% increase in the endocardial perimeter length of noninfarcted segments. Serial M mode echocardiographic studies showed no significant change in the wall thickness of noninfarcted myocardial segments. Hemodynamic changes that occurred in this subgroup of patients included significant decreases in left ventricular end-diastolic and pulmonary capillary wedge pressures (p less than .05) and significant increases in angiographic cardiac index (p less than .01) and LVESV index (p less than .01). We conclude that in patients who manifest cardiac dilatation in the early convalescent period after myocardial infarction, there is remodeling of the entire left ventricle including infarct expansion of akinetic-dyskinetic segments and volume-overload hypertrophy of noninfarcted segments.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1983

Clinical angiographic regression of atherosclerosis after partial ileal bypass.

Clinical documentation of atherosclerotic plaque regression has been difficult to obtain. This is a report of a patient with severe and early atherosclerotic cardiovascular disease with regression of at least three major atherosclerotic lesions demonstrated by coronary arteriography 10 years after partial ileal bypass operation. The patient's total plasma cholesterol was reduced over these 10 years, ranging from 40% to 23%, from the preoperative level of 757 mg/dl. Sequential arteriograms were assessed independently by several arteriographers and blindly by the Arteriography Review Panel of the Program on Surgical Control of the Hyperlipidemias (POSCH). The readings were analyzed by 4 grading methods. Unanimously, marked regression was read in the proximal left circumflex artery (70% leads to 20%), middle segment of the right coronary artery (45% leads to 20%), and in the distal right coronary artery (80% leads to 50%). Thus, by any and all of the methods used, there was significant regression of arteriographically demonstrated atherosclerotic lesions.

Adult↗