Alfred F. Parisi

Coronary calcification in the diagnosis of coronary artery disease

Clinical, postmortem and angiographic studies of coronary calcification are reviewed to define the value of fluoroscopy in the diagnosis and management of coronary artery disease. Autopsy studies consistently show a unique association between calcification of the coronary arteries and atherosclerosis. The relation of coronary calcification to the presence of major stenosis is more variable but is strong enough to be of clinical value, particularly in the younger subject. The diagnostic value of fluoroscopy can be improved by attention to the detailed features of calcification observed with the technique. Combined use of fluoroscopy and exercise testing appears to be a valid and as yet unexploited approach to the noninvasive diagnosis of coronary stenosis. Fluoroscopy has been a neglected method of noninvasive diagnosis and is sufficiently promising to warrant greater clinical use.

Perioperative myocardial infarction after coronary artery bypass surgery. Clinical significance and approach to risk stratification.

The clinical significance of perioperative myocardial infarction (MI) after coronary artery bypass surgery is not known. Therefore, strategies for the risk stratification of these patients do not exist. This study was undertaken to define the effect of perioperative MI on prognosis after discharge from the hospital and to develop an approach to the risk stratification of these patients. Fifty-nine patients with and 115 patients without perioperative MI were observed for 30 months for the development of cardiac events (death, nonfatal MI, and admission to hospital for unstable angina or congestive heart failure). Patients with perioperative MI were significantly more likely than patients without to have a cardiac event (31% versus 12%, p less than 0.01) and multiple events (19% versus 1%, p less than 0.001). Cox regression analysis identified two independent predictors of cardiac events other than perioperative MI (relative risk, 2.7): inadequate revascularization (relative risk, 3.5) and depressed (less than 40%) postoperative ejection fraction (EF) (relative risk, 2.1). Event-free survival rate of patients with perioperative MI varied markedly depending on the number of other negative prognostic variables present. Patients with perioperative MI who were adequately revascularized and had a postoperative EF greater than 40% had an event-free survival rate similar to patients without a perioperative MI (92% versus 87%, p = NS). Patients with perioperative MI who were inadequately revascularized and had depressed postoperative EF had an event-free survival rate of 13% (p less than 0.001 versus all other subsets). Event-free survival rate was intermediate (68%) in patients with perioperative MI and with only one of the other two variables (p less than 0.001 versus other subsets). In conclusion, perioperative MI adversely affects prognosis. Patients can be stratified into low, high, and intermediate risk subsets based on a simple assessment of the adequacy of revascularization and a determination of residual left ventricular function.

Medical compared with surgical management of unstable angina. 5-year mortality and morbidity in the Veterans Administration Study.

We evaluated medical in comparison to surgical plus medical (surgical) treatment of unstable angina using a prospective randomized protocol that stratified patients by clinical presentation and by invasive evaluation of left ventricular (LV) function. Clinical presentations were as follows--type 1: progressive or new onset angina relieved by medication; type 2: prolonged bouts of angina poorly or incompletely relieved by medication. Abnormal LV function was arbitrarily defined as ejection fraction less than 0.50 or LV end-diastolic pressure 16 mm Hg or more. Of 468 patients, 237 were assigned to medical and 231 to surgical therapy. There were 374 type 1 and 94 type 2 patients. LV function was normal in 334 and abnormal in 134 patients. Compared with results at 24 months, this 60-month follow-up study showed important differences in survival for patients with three-vessel disease: 75% for medical and 89% for surgical patients (p less than 0.02). The cumulative 5-year rate of repeat hospitalizations for cardiac reasons was less with surgical patients for either clinical presentation. For type 1, medical patients had a 56% rate, and surgical patients had a 42% rate (p = 0.004). For type 2, medical patients had a 62% rate, and surgical patients had a 43% rate (p = 0.05). Overall mortality did not differ between the two treatments, and this remained true in type 1 versus type 2 patients and in those with normal versus abnormal LV function. However, regression analysis of medical and surgical groups with ejection fraction as a continuous variable showed that mortality of medical patients depended on ejection fraction (p = 0.004), whereas the mortality of surgical patients did not (p = 0.76), and survival in the surgical group was higher in the lowest ejection fraction tercile-73% for medical and 86% for surgical patients, p = 0.03. We conclude that surgery improves survival in patients with three-vessel disease and leads to fewer subsequent hospitalizations for cardiac reasons. An impaired ejection fraction had an adverse impact on survival of medical patients but not on surgical patients, and mortality in surgical patients was improved compared with medical patients in the lowest ejection fraction tercile.

Clinical Validation of an Edge Detection Algorithm for Two-Dimensional Echocardiographic Short-Axis Images

The purpose of this study was to validate an edge detection algorithm for short-axis two-dimensional echocardiographic studies in a protocol that stimulated its implementation at multiple clinical laboratories. Six short-axis two-dimensional echocardiographic studies were solicited from each of five clinical laboratories. A single cardiac cycle from each of the resulting 30 studies was entered into the computer system. Five expert observers came to the laboratory on separate occasions and traced endocardial borders from the short-axis studies on 2 separate days. The computer algorithm generated borders on each frame of the cardiac cycles on the basis of regions of search defined by the observers. Of the 30 original studies, five were considered excellent, seven were good, nine were poor, and nine were technically inadequate by consensus of the five observers. The correlation coefficient for computer-defined borders with manually defined borders in the excellent quality studies was 0.985. Interobserver variability was expressed as the mean percent area difference for all possible pairings of observers. The mean percent area differences were decreased from +/- 9.8% to +/- 5.3%, +/- 12.5% to +/- 8.4%, and +/- 17.4% to +/- 15.6% when comparing observer with computer-generated borders in the excellent, good, and poor quality studies, respectively. Intraobserver variability was expressed as decrease in mean percent area difference on corresponding frames between days 1 and 2. Intraobserver variability was decreased from +/- 6.5% to +/- 4.5%, +/- 10.8% to +/- 7.0%, and +/- 14.0% to +/- 11.9%, respectively. All reductions in variability were statistically significant at p less than 0.01. Observer acceptance of computer-defined borders was estimated at 94%, 93%, and 97% for excellent, good, and poor quality studies, respectively. Once the observer defined a region of search, computer process time to generate all borders in the cardiac cycle was approximately 4 minutes. The conclusion is that the algorithm produces accurate, reliable, and acceptable borders.

Aortic valve replacement for ochronosis of the aortic valve.

A patient with generalized ochronosis developed severe cardiovascular symptoms related to ochronotic deposits on the aortic valve and in the coronary arteries. A transvalvular gradient of 100 mm Hg and obstruction of the left anterior descending coronary artery were found by catheterization. Aortic valvular replacement and aortocoronary bypass were performed successfully, and the patient has been well two years since operation. This represented the first reported case of aortic valve replacement for this rare metabolic condition. With increased mobility of these patients due to aggressive orthopedic joint treatment, more patients with this syndrome may require surgery for cardiovascular symptoms.

The case for echocardiography in acute myocardial infarction

Acute myocardial infarction occurs after a period of profound myocardial ischemia. Ischemia of this degree immediately produces a regional contraction abnormality, which is readily detectable by echocardiography before the onset of necrosis. Echocardiography has been used both experimentally and clinically as a guide to the functional extent of myocardial involvement in evolving infarction and hence provides an objective anatomic basis for electing therapeutic interventions and assessing a prognosis.

Characteristics and outcome of medical nonadherers in the Veterans Administration Cooperative Study of Coronary Artery Surgery.

During a 7-year follow-up period in the Veterans Administration Study of Bypass Surgery, 75 (24%) of 311 medically assigned patients without left main disease crossed over to surgical treatment. Nineteen baseline, clinical, electrocardiographic and angiographic characteristics of the 75 crossover patients were compared with those of the 236 patients who adhered to medical treatment. At entry into the study, the crossover group contained more patients with severe angina than did the medical adherers group (p less than 0.05) and fewer patients with electrocardiographic evidence of previous myocardial infarction (p less than 0.05). Other entry characteristics were similar in distribution among those in the medical-adherer and crossover groups. The 2 major reasons for crossover were persistence or progression of angina, which occurred in 43 and 37% of the 75 crossover patients, respectively. There was no relation between progression of symptoms and angiographic progression of coronary narrowing. Thus, crossover was not determined by more severe coronary narrowing, but was associated with more severe symptoms and a lower incidence of infarction. The medically randomized patients who later underwent surgery (medical nonadherers) experienced the same relief of angina 1 year after surgery as did the surgically randomized patients who initially received surgery (surgical adherers); however, their overall 7-year survival was lower (77% for medical nonadherers vs 83% for surgical adherers; difference not significant).

Echocardiographic Approaches to the Evaluation of Acute Myocardial Infarction

Acute myocardial infarction is a dynamic process. Occlusion of a coronary artery results in regional myocardial hypoperfusion. When regional blood flow falls below the level needed to meet myocardial demands active contraction is replaced by aneurysmal bulging in the malperfused area (1). After 30–45 minutes of ischemia, a “wave” of necrosis begins in the endocardium which progresses radially towards the epicardium (2). After six hours necrosis is complete and healing begins (2). Tissue edema swells the region of necrosis while inflammatory and scavenger cells flood the area over the ensuing week (3). Collagenous (“scar”) tissue is then deposited and the injured region shrinks in size over the next six weeks (4,5).