PubMed Health⌕ Search

Biomedical subjects

M E Assey

Publications and source records attributed to M E Assey.

At least 19 recordsLinked to original sources
PubMed2001

Treatment of coronary artery disease in hemodialysis patients: PTCA vs. stent.

This retrospective study examined the utilization of coronary stent placement versus PTCA in hemodialysis patients with obstructive coronary disease. Prior studies have demonstrated suboptimal results with PTCA owing primarily to high rates of restenosis. We identified 19 hemodialysis patients who received a percutaneous coronary intervention who were matched with individuals without renal failure undergoing same vessel revascularization. Our study found that 71% of hemodialysis patients receiving PTCA had a recurrent cardiac event defined by subsequent angina, myocardial infarction, or cardiac death. At follow-up, 30% of patients who received stent placement had recurrent cardiac events. Intracoronary stent placement is both safe and feasible and produces more favorable clinical outcomes in the management of coronary disease in hemodialysis patients.

Adult↗
PubMed1999

Heart catheterization in the patient with valvular heart disease.

Despite impressive advances in non-invasive technology, cardiac catheterization remains the gold standard for the evaluation of patients considered for valve surgery. Diagnostic information should be combined with non-invasive measurements, particularly serial non-invasive echocardiographic assessments, to allow for optimal management decisions. For adult patients with risk factors for coronary artery disease, we do not believe there is any substitute for selective coronary angiography. The availability of non-ionic contrast agents, pre-assessment by thorough physical examination and non-invasive techniques, allows safe cardiac catheterization even in patients who are severely compromised by congestive heart failure and/or coronary artery disease.

Adult↗
PubMed1993

Effect of catheter positioning on the variability of measured gradient in aortic stenosis.

The purpose of this study was to quantify the variation in measured aortic valve gradient and calculated aortic valve area when different techniques of cardiac catheterization were utilized. Hemodynamic assessment of aortic stenosis severity requires an accurately determined pressure gradient. In aortic stenosis, the presence of intraventricular pressure gradients and downstream pressure recovery within the aorta means that a range of aortic valve gradients could be measured in a given patient depending upon catheter position and measurement technique. To quantify the degree of variation in measured gradient and calculated aortic valve area, we generated transvalvular gradients by nine different techniques in 15 patients (11 men, 4 women; 29-86 years old). Patients were divided into those with severe aortic stenosis (aortic valve area < or = 0.6 cm2, n = 6) and those with moderately severe aortic stenosis (aortic valve area 0.61-0.90 cm2, n = 9). Considerable variation in measured gradient and calculated aortic valve area was observed. The maximum variation in gradient was similar in severe and moderately severe aortic stenosis groups (33 mm Hg. vs. 32 mm Hg., p = NS). However, the variation in gradient as a percent of maximum gradient was greater (P < 0.05) in the moderately severe aortic stenosis group. The maximum variation in calculated aortic valve area was 0.1 cm2 in the severe group and 0.3 cm2 in the moderately severe group (P < 0.01). An intraventricular gradient, present in 13 of 15 (87%) patients, was partially responsible for the variation in pressure gradient measurement and calculated aortic valve area.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

The puzzle of normal coronary arteries in the patient with chest pain: what to do?

Over one million Americans undergo cardiac catheterization each year because of chest pain, with the expectation that coronary artery disease will be found. However, up to 30%--a subgroup that includes patients with both cardiac and noncardiac pathology--will have angiographically normal coronary arteries. While the prognosis of the group as a whole is excellent, successful management requires a clear understanding of the multiple and varied conditions that can cause this syndrome.

Adult↗
PubMed1992

Cardiovascular status of panic disorder patients with and without prominent cardiac symptoms.

The extent of the cardiovascular evaluation of panic disorder patients with cardiac symptoms remains a dilemma for the clinician. The authors conducted a pilot study to assess the cardiac status of 20 panic disorder patients, 10 of whom had prominent cardiac symptoms and 10 of whom did not. No differences in the cardiac abnormalities were found between the groups. These findings suggest that panic disorder patients with cardiac symptoms are not more likely to have cardiac disease than those without prominent cardiac symptoms. The practical implications of these findings are discussed.

Adult↗
PubMed1990

Indications for heart valve replacement.

Proper evaluation of the patient with valvular heart disease begins with a thorough history and physical examination. Today, sophisticated noninvasive tests--especially echocardiography with color flow Doppler imaging--complement the information gained at cardiac catheterization. Information previously available only through cardiac catheterization can now be obtained from these noninvasive techniques. Serial evaluations can be performed, which are important in managing lesions of borderline hemodynamic significance and in avoiding subclinical deterioration of left ventricular contractility. Improvements in surgical expertise and intraoperative myocardial preservation allow postoperative improvement for patients with aortic stenosis and aortic insufficiency despite the presence of left ventricular systolic dysfunction. Many traditional indicators of a poor operative result in aortic insufficiency appear less reliable today. Consequently, these indicators should never be viewed in isolation or be given preeminence over clinical judgment. The long-term results following aortic valvuloplasty have been disappointing. However, mitral valvuloplasty--for technically suitable types of mitral stenosis--is an attractive alternative to surgery. Echocardiography may be helpful in selecting patients best suited for this technique. The timing of valve replacement in mitral insufficiency is made difficult by the altered loading conditions which can mask underlying contractile dysfunction. In this regard, the use of end-systolic measurements (e.g., end-systolic stress-volume ratio) more accurately characterized left ventricular contractility. When mitral insufficiency patients with left ventricular systolic dysfunction require surgery, valve repair appears superior to traditional mitral valve replacement. With valve repair, the postoperative left ventricular ejection fraction is usually higher, as left ventricular contractile reserve is better maintained.

Aortic Valve↗
PubMed1990

Increased platelet thromboxane A2/prostaglandin H2 receptors in patients with acute myocardial infarction.

Platelets have been implicated in the formation of occlusive intracoronary thrombi leading to unstable angina pectoris and acute myocardial infarction. Evidence of platelet involvement in these syndromes includes increased thromboxane A2 synthesis during ischemic events and enhanced in vitro sensitivity to agonists. To determine the density and affinity of platelet thromboxane A2/prostaglandin H2 (TXA2/PGH2) receptors in patients with acute myocardial infarction and unstable angina pectoris, the maximum number of binding sites (Bmax) per platelet and the dissociation constant (Kd) of the TXA2/PGH2 receptor antagonist, [125I]-PTA-OH, was determined at equilibrium in washed platelets. Patients with acute myocardial infarction had a significantly (p = 0.006) higher Bmax (4,468 +/- 672 sites/platelet, n = 9) compared with controls (2,206 +/- 203 sites/platelet, n = 8). Restudied at a time when the patients' coronary artery disease was clinically stable, Bmax values for the myocardial infarction group had returned to within normal limits. The dissociation constant for [125I]-PTA-OH was not significantly different in the acute myocardial infarction patients compared with controls. In patients with acute myocardial infarction, the duration of chest pain was positively correlated (r = 0.71, p less than 0.02) with the number of [125I]-PTA-OH binding sites (Bmax). In vitro platelet sensitivity to the TXA2/PGH2 mimetic, U46619, was assessed in aggregation studies. The maximal velocity of aggregation (slope) correlated with platelet TXA2/PGH2 receptor number (r = 0.67, p less than 0.001) and was significantly higher (p less than 0.02) in the acute myocardial infarction patients compared with the other study groups. There was no significant difference in the aggregation EC50 values for the thromboxane mimetic U46619 between unstable angina, acute myocardial infarction, and control groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Prognosis in stable angina pectoris and silent myocardial ischemia.

The results of current investigation suggest that a former clinical standby, namely, the presence or absence of angina, is no longer the principal prognostic factor for determining a patient's risk of cardiac events, including myocardial infarction. In a retrospective analysis, patients with chronic stable angina were compared on the basis of presence or absence of angina during ischemia detected by thallium imaging. Patients were similar in terms of risk factors, clinical characteristics and catheterization data. At 30 months of follow-up, the myocardial infarction rate was 22% in the silent group compared with 4% in the group with angina. Transient asymptomatic ischemia has prognostic value independent of other variables such as exercise stress testing or cardiac catheterization data. Future prognostic studies should be careful to include patient populations with similar characteristics; they also will need to provide protracted follow-up and utilize sensitive and reproducible diagnostic techniques.

Angina Pectoris↗
PubMed1988

Silent myocardial ischemia. Answers to frequently asked questions.

Patients with coronary artery disease and silent myocardial ischemia have a prognosis similar to that of symptomatic patients. Screening of totally asymptomatic patients is not likely to identify many with silent ischemia. However, certain cohorts of patients--middle-aged men with two or more risk factors for coronary arteriosclerosis--are at risk of presenting initially with myocardial infarction or sudden death, and the screening of such persons is advised. Use of radionuclear imaging techniques during exercise stress testing appears to be helpful in identifying patients at high risk, who should then be offered coronary arteriography. An ideal treatment has not been established, but a treatment strategy based on symptom relief alone is suboptimal. Measures used for symptomatic ischemia are just as effective with silent ischemia. Treatment must be individualized, and ambulatory electrocardiographic monitoring appears useful in adjusting antiischemic therapy for a given patient.

Angina Pectoris↗
PubMed1988

Alterations in left ventricular geometry, wall stress, and ejection performance after correction of congenital aortic stenosis.

Children with congenital aortic stenosis have "excessive" left ventricular hypertrophy with reduced resting systolic wall stress that allows for supernormal ejection performance. If aortic stenosis is uncorrected, this pattern persists until adulthood. The effect of removing the aortic pressure gradient on left ventricular hypertrophy and wall stress in children with congenital aortic stenosis is unknown. To test the hypothesis that removal of the stimulus for hypertrophy by aortic valve replacement or repair would normalize left ventricular mass and wall stress, we measured left ventricular ejection performance, wall stress, and contractile function in seven patients at cardiac catheterization before and 36 +/- 7 months after surgical correction of congenital aortic stenosis. After aortic valve replacement or repair, the aortic valve gradient fell from 87 +/- 12 to 7 +/- 4 mm Hg, and peak left ventricular pressure fell from 187 +/- 14 to 128 +/- 8 mm Hg. Left ventricular ejection fraction decreased postoperatively from 86 +/- 4% to 74 +/- 4% (p less than 0.001), whereas velocity of circumferential fiber shortening decreased from 2.15 +/- 0.15 to 1.6 +/- 0.11 (p less than 0.002). Left ventricular mass remained unchanged preoperatively (121 +/- 14 g/m2) and postoperatively (121 +/- 16 g/m2), but wall thickness (h) decreased in relation to ventricular radius (r) (h/r = 0.55 +/- 0.05 preoperatively, 0.36 +/- 0.02 postoperatively; p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve↗
PubMed1988

Screening for silent myocardial ischemia.

Since many patients do not experience angina prior to myocardial infarction or sudden death, screening of asymptomatic high-risk patients is necessary. Exercise stress testing of asymptomatic patients with coronary risk factors can be performed by family physicians in their offices. For the physician trying to develop a rational screening policy for silent myocardial ischemia, the relatively low yield of positive test results creates a management dilemma.

Adult↗
PubMed1987

Incidence of acute myocardial infarction in patients with exercise-induced silent myocardial ischemia.

Fifty-five patients with angiographically proved coronary artery disease (CAD) underwent Bruce protocol exercise stress testing with thallium-201 imaging. Twenty-seven patients (group I) showed myocardial hypoperfusion without angina pectoris during stress, which normalized at rest, and 28 patients (group II) had a similar pattern of reversible myocardial hypoperfusion but also had angina during stress. Patients were followed for at least 30 months. Six patients in group I had an acute myocardial infarction (AMI), 3 of whom died, and only 1 patient in group II had an AMI (p = 0.05), and did not die. Silent myocardial ischemia uncovered during exercise stress thallium testing may predispose to subsequent AMI. The presence of silent myocardial ischemia identified in this manner is of prognostic value, independent of angiographic variables such as extent of CAD and left ventricular ejection fraction.

Angina Pectoris↗
PubMed1987

Predictors of outcome for aortic valve replacement in patients with aortic regurgitation and left ventricular dysfunction: a change in the measuring stick.

Although left ventricular function is generally regarded as a key determinant of prognosis in aortic regurgitation, predictors of outcome of aortic valve replacement based on this factor have recently been questioned. This study was performed to examine the role of indexes of left ventricular function in predicting the outcome of surgery in patients with aortic regurgitation and left ventricular dysfunction. Fourteen patients with aortic regurgitation with a preoperative ejection fraction of less than 0.55 (average 0.45 +/- 0.02) who underwent aortic valve replacement were studied. The patients had 82 (58%) of a possible 140 predictors of negative outcome preoperatively, but 12 of the 14 patients had a decrease in symptoms and an increase in ejection fraction into the normal range after operation (average postoperative ejection fraction 0.59 +/- 0.04). Although improvement occurred despite the presence of many negative predictors of outcome, there was a significant correlation between postoperative ejection fraction and eight of the tested preoperative predictors. Preoperative end-systolic dimension correlated best (r = -0.91) with postoperative ejection fraction. An end-systolic dimension of 60 mm correlated with a postoperative ejection fraction of 0.55. The results indicate that preoperative ventricular function is still an important determinant of outcome of aortic valve replacement for aortic regurgitation. However, current medical and surgical techniques permit a better prognosis in the presence of reduced ventricular function than was previously considered possible.

Aortic Valve Insufficiency↗
PubMed1987

Unexpected persistence into adulthood of low wall stress in patients with congenital aortic stenosis: is there a fundamental difference in the hypertrophic response to a pressure overload present from birth?

Congenital aortic stenosis in children is characterized by low left ventricular systolic wall stress allowing for supernormal ejection performance. In contrast, adults with acquired aortic stenosis have normal or excessive systolic wall stress resulting in either normal or subnormal ejection performance. In this study young children with congenital aortic stenosis, older children and adults with congenital aortic stenosis, and adults with acquired aortic stenosis were evaluated to test the hypothesis that the childhood pattern of low wall stress would convert to the adult pattern with advancing age. Left ventricular end systolic wall stress was lower in both congenital aortic stenosis groups when compared with that in age-matched normal subjects or adults with acquired aortic stenosis. Ejection fraction was higher in both groups of patients with congenital aortic stenosis than in age-matched controls. There was no tendency in the 16 patients with congenital aortic stenosis, some of whom were followed to the age of 33, for the congenital pattern of wall stress and ventricular performance to convert to the adult pattern. These results suggest that there is a fundamental difference in the hypertrophic response to a pressure overload present at birth compared with the response to one acquired later in life.

Adult↗