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Biomedical subjects

E Braunwald

Publications and source records attributed to E Braunwald.

At least 199 records · Page 11Linked to original sources
PubMed1991

Rationale and design of a secondary prevention trial of lowering normal plasma cholesterol levels after acute myocardial infarction: the Cholesterol and Recurrent Events trial (CARE)

Recent clinical trials of primary and secondary prevention of cardiovascular disease have demonstrated that lowering plasma cholesterol decreases the incidence of coronary heart disease in patients with elevated plasma cholesterol. However, it is not known whether patients with established coronary artery disease and normal plasma cholesterol can be benefited. Several previous prevention trials reviewed in this report found that patients who had plasma cholesterol levels at baseline in the upper portion of the eligibility range (e.g., greater than 240 mg/dl) received greater benefit from hypolipidemic diet or drug therapy than patients who had lower plasma cholesterol levels at baseline. The recent availability of drugs that are more potent and less prone to cause adverse reactions than previous regimens permits this important question to be addressed. The Cholesterol and Recurrent Events trial is testing whether pravastatin, a hydroxymethylglutaryl coenzyme A reductase inhibitor, will decrease the sum of fatal coronary heart disease and nonfatal myocardial infarction (MI) in patients who have recovered from a MI and who have normal total cholesterol levels. Fatal cardiovascular disease and total mortality are important secondary end points. The trial is enrolling 4,000 men and women from 80 centers throughout North America, age 21 to 75 years, who have survived MI for 3 to 20 months, who have plasma total cholesterol less than 240 mg/dl (6.2 mmol/liter) and low-density cholesterol of 115 to 174 mg/dl (3.0 to 4.5 mmol/liter), and who are representative of the general population of patients with MI. Patients are randomized to either active or inactive drug therapy. Active therapy consists of pravastatin, 40 mg/day, designed to achieve an average decrease in low-density lipoprotein cholesterol of approximately 30%, and an increase in high-density lipoprotein of 5%. The average duration of follow-up will be greater than or equal to 5 years. To protect against a lower than expected rate of recurrent events, the trial will be continued until a predetermined fixed number of coronary heart disease events occurs in the entire cohort so that the original sensitivity of the trial will be maintained.

Adult↗
PubMed1991

Ventricular enlargement and remodeling following acute myocardial infarction: mechanisms and management.

Severe myocardial ischemia, when sustained, leads to a predictable sequence of events, including myocardial necrosis, expansion of the infarct, and later its replacement by scar tissue. The nonischemic tissue sustains ventricular function, but it frequently adapts to the extra load placed on it by dilating. The enlargement and remodeling of the left ventricle may lead to ventricular failure and arrhythmias. Rational management to prevent these complications includes restoration of the patency of the occluded vessel and ventricular unloading. These two interventions may be useful both early and late in the course of infarction.

Cardiomegaly↗
PubMed1991

Patency of the infarct-related coronary artery and ventricular geometry.

The pathogenesis of acute myocardial infarction (AMI) involves a sudden thrombotic occlusion of a coronary artery. Spontaneous or pharmacologic thrombolysis may lead to myocardial salvage if patency is achieved within a narrow time window. However, patients in whom thrombolysis occurs late seem to demonstrate improved left ventricular (LV) function and prognosis, which may be independent of myocardial salvage. Preservation of normal LV geometry by reducing expansion of the infarcted segment is a likely mechanism for this benefit. Infarct expansion is most pronounced in patients with anterior wall AMI who have a persistently occluded infarct-related vessel. This process of expansion leads to early increases in LV volume and distortions of LV contour (abnormal LV geometry). Patients whose infarct segment is largest, patients who have manifested infarct expansion, and patients with a persistently occluded infarct-related artery are at highest risk for progressive LV dilation. Experimental data support the concept that reperfusion of occluded vessels that occurs too late for myocardial salvage will preserve LV geometry by limiting infarct expansion. Prospective clinical trials should address whether there is a late, "second time window" during which infarct expansion and distortions of LV geometry may be reduced by (1) therapy with thrombolytic agents applied late after infarction, (2) late mechanical reperfusion with percutaneous transluminal coronary angioplasty (PTCA) or related methods, and (3) load-reducing agents to decrease remodeling, such as angiotensin-converting enzyme inhibitors or nitroglycerin.

Animals↗
PubMed1991

Rationale, design and baseline characteristics of the survival and ventricular enlargement trial. SAVE Investigators.

Heart failure, often associated with ventricular enlargement and recurrent myocardial infarction, is one of the major causes of postinfarction mortality. This observation suggests that measures used to prevent ventricular enlargement may improve postinfarction survival. The Survival and Ventricular Enlargement (SAVE) trial is a randomized, double-blind, placebo-controlled clinical trial with the purpose of evaluating the effect of angiotensin-converting enzyme (ACE) inhibition on postinfarction death and ventricular dilation. This multicenter trial had a sample size goal of 2,220 patients between 21 and 79 years of age who had recently sustained a myocardial infarction and who have an ejection fraction determined by radionuclide ventriculogram (RVG-EF) of less than or equal to 40%. In addition to conventional therapy, patients were randomly assigned to captopril or placebo therapy commencing within 3-16 days following their myocardial infarction. A second RVG-EF is performed on all surviving participants at the end of the average 3.5-year treatment and follow-up period. The study has 90% power to detect a 25% improvement in postinfarction mortality or prevention of greater than or equal to 9 unit absolute reduction in radionuclide ejection fraction. Additional end points, design features, and the administrative organization of the trial are described.

Adult↗
PubMed1991

Ventricular enlargement following infarction is a modifiable process.

The dilation and distortion of the left ventricle that may occur as a consequence of myocardial infarction are associated with a heightened risk for adverse cardiovascular events. Infarcts that are extensive, transmural, and involve the apex as well as persistently occluded, infarct-related coronary arteries are predisposing factors for ventricular enlargement. Infarct expansion is an early component of the overall process of volume enlargement, which later continues as a volume overload hypertrophy of the remaining myocardium. Therapy to limit myocardial necrosis has been associated with the preservation of a more normal ventricular architecture. The late phase of ventricular remodeling has also been shown to be amendable to therapy, as chronic administration of angiotensin-converting enzyme (ACE) inhibitors has been associated with a reduction in the extent of ventricular dilation. There is currently a great deal of clinical investigative interest not only in whether ACE inhibition therapy following acute myocardial infarction will result in preservation of ventricular volume and topography, but, more importantly, whether it will lead to an improvement in clinical outcome.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1991

Subspecialists and internal medicine: a perspective.

There is a growing schism between general internal medicine and the medical subspecialties. The latter are functioning increasingly as categorical disease centers, such as cardiac or cancer centers, which involve subspecialists from several departments. These new "horizontal" organizational units are thought to enhance the effectiveness of patient care as well as the generation of resources, especially for research and training. However, subspecialists operating outside of the framework of training, accreditation, and standards established by internal medicine are at risk for being less effective in dealing with the "whole" patient. Further, the critical evaluation of clinical practices of subspecialists is greatly needed and is far more likely to be accomplished effectively within departments of internal medicine than in categorical disease centers. Therefore, although some strengthening of the new horizontal organizational units now seems appropriate, this process must not be allowed to erode the important integrating structure provided by internal medicine.

Internal Medicine↗
PubMed1991

Stunning of the myocardium: an update.

When severely ischemic myocardium is reperfused, prolonged myocardial dysfunction--a phenomenon named myocardial stunning--frequently occurs. Stunning also occurs in a variety of other situations. These include myocardium located adjacent to infarcted tissue, transient increase in myocardial O2 demands in the presence of incomplete coronary obstruction, during both systole and diastole, in isolated perfused hearts rendered ischemic or anoxic, and in a variety of clinical situations, such as following ischemic arrest in cardiac surgery, thrombolytic reperfusion, and after episodes of severe ischemia in Prinzmetal's angina or unstable angina. Although the fundamental mechanism(s) responsible for myocardial stunning has not been elucidated, in experimental preparations calcium antagonists, free-radical scavengers, and neutrophil depletion have each been found to be helpful in minimizing it.

Animals↗
PubMed1991

Prognostic significance of the Karnofsky Performance Status score in patients with acute myocardial infarction: comparison with the left ventricular ejection fraction and the exercise treadmill test performance. The MILIS Study Group.

The prognostic significance of functional status has not been previously studied in the setting of acute myocardial infarction. We assessed the Karnofsky Performance Status (KPS) score, a simple functional status scale that is commonly used to categorize physical ability, in 849 patients with acute myocardial infarction who were enrolled in the Multicenter Investigation of the Limitation of Infarct Size (MILIS) study. We then compared the KPS score with other predictors of prognosis in these patients. In patients who presented with acute myocardial infarction, a lower KPS score (less than 8 on a scale of 1 to 10) 3 weeks before the index infarction was associated with a higher incidence of congestive heart failure, in-hospital cardiac arrest, and mortality during hospitalization, as compared with patients with KPS scores greater than or equal to 8 (each p less than 0.001). Cumulative 1-year and 4-year mortality rates were significantly higher in patients with KPS scores less than 8, as compared with patients with KPS scores greater than or equal to 8 (42.5% vs. 12.6% at 1 year and 61.6% vs 25.1% at 4 years, respectively; both p less than 0.001). The left ventricular ejection fraction on admission was significantly lower in patients with KPS scores less than 8, as compared with those with KPS scores greater than or equal to 8 (p less than 0.019). The cumulative mortality rate was equally well predicted by low KPS score and by left ventricular ejection fraction (both p less than 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Disability Evaluation↗
PubMed1991

Resolved and unresolved issues in the prevention and treatment of coronary artery disease: a workshop consensus statement.

Advances in cardiovascular research during the past two decades have resulted in an improved understanding of the chain of events that lead to end-stage coronary artery disease. These developments have been paralleled by therapeutic advances that now make it possible to intervene at virtually every stage in the development of advanced cardiac disease, from asymptomatic persons at risk of developing coronary atherosclerosis to patients with end-stage heart failure. By interrupting this chain of events, perhaps at multiple sites, it may be possible to prevent or slow the development of symptomatic heart disease and hopefully prolong life. Many opportunities exist for obtaining further information regarding the underlying pathophysiology, the fundamental mechanisms of action of interventions designed to prevent and/or treat the development of myocardial ischemia and cardiac failure and for effecting favorably the natural history of various forms of heart disease.

Coronary Disease↗
PubMed1991

Selective versus routine predischarge coronary arteriography after therapy with recombinant tissue-type plasminogen activator, heparin and aspirin for acute myocardial infarction. TIMI II Investigators.

To ascertain whether predischarge arteriography is beneficial in patients with acute myocardial infarction treated with recombinant tissue-type plasminogen activator (rt-PA), heparin and aspirin, the outcome of 197 patients in the Thrombolysis in Myocardial Infarction (TIMI) IIA study assigned to conservative management and routine predischarge coronary arteriography (routine catheterization group) was compared with the outcome of 1,461 patients from the TIMI IIB study assigned to conservative management without routine coronary arteriography unless ischemia recurred spontaneously or on predischarge exercise testing (selective catheterization group). The two groups were similar with regard to important baseline variables. During the initial hospital stay, coronary arteriography was performed in 93.9% of the routine catheterization group and 34.7% of the selective catheterization group (p less than 0.001), but the frequency of coronary revascularization (angioplasty or coronary artery bypass surgery) was similar in the two groups (24.4% versus 20.7%, p = NS). Coronary arteriograms showed a predominance of zero or one vessel disease (stenosis greater than or equal to 60%) in both groups (routine catheterization group 73.1%, selective catheterization group 61.3%). During the 1st year after infarction, rehospitalization for cardiac reasons and the interim performance of coronary arteriography were more common in the selective catheterization group (37.9% versus 27.6%, p = 0.007 and 28.6% versus 11.6%, p less than 0.001, respectively); however, the interim rates of death, nonfatal reinfarction and performance of coronary revascularization procedures were similar. At the end of 1 year, coronary arteriography had been performed one or more times in 98.9% of the routine catheterization group and 59.4% of the selective catheterization group (p less than 0.001), whereas death and nonfatal reinfarction had occurred in 10.2% versus 7.0% (p = 0.10) and 8.6% versus 9.0% (p = 0.87), respectively. Because the selective coronary arteriography policy exposes about 40% fewer patients to the small but finite risks and inconvenience of the procedure without compromising the 1 year survival or reinfarction rates, it seems to be an appropriate management strategy.

Aged↗
PubMed1991

Progressive ventricular remodeling in rat with myocardial infarction.

Ventricular dilatation may have important prognostic implications for the survival of patients with left ventricular (LV) dysfunction. To determine the manner and extent to which the left ventricle of the rat remodels and dilates after myocardial infarction, we obtained the passive pressure-volume relationships, chamber stiffness constants, and mass during both the early and late phases. In moderate and large infarcts as inflammation and edema developed, LV weight increased then progressively decreased as a thin scar formed, returning to normal values as a result of compensatory hypertrophy of the residual myocardium. LV dilatation occurred in all rats with infarcts but to different extents depending on infarct size and duration. In the early postinfarction phase, pressure-volume relationship was relatively unchanged in all infarct-size groups, except for significant rightward shift in low pressure range for rats with moderate and large infarcts and significant leftward shift in high pressure range for rats with small infarcts. During resolution of the inflammatory response, LV dilatation occurred in all infarct groups in relation to infarct size. As scar formation became complete, LV enlargement did not progress in rats with small infarcts but did so in rats with moderate and large infarcts. LV chamber stiffness remained within the range of normal values during the early phase in all rats with infarcts but decreased significantly during the late phase in rats with moderate and large infarcts in association with the extent of ventricular enlargement. Alterations in the volume-to-mass ratio (V/Vwt) were most marked in the late postinfarction phase, wherein both volume (increased) and mass (decreased, then increased) changed dramatically and V/Vwt progressively increased in rats with large infarcts.

Animals↗
PubMed1990

Comparison of coronary and myocardial morphologic findings in patients with and without thrombolytic therapy during fatal first acute myocardial infarction. The TIMI Investigators.

The hearts of 61 patients (39 men aged 64 +/- 11 years) who died from 5 hours to 42 days (median 3 days) after a fatal first acute myocardial infarction without having undergone percutaneous transluminal coronary angioplasty or coronary bypass surgery were studied to compare clinical and cardiac morphologic features of patients receiving thrombolytic therapy with tissue-plasminogen activator (t-PA) to those not receiving thrombolytic therapy. Comparison of findings in the 23 patients who received t-PA intravenously 3 +/- 1 hours after onset of symptoms, with the 38 patients who did not, showed similar baseline characteristics with respect to: age, gender, history of hypertension; location of the infarct; heart weight; severity and numbers of coronary arteries narrowed; and frequencies of plaque rupture, plaque hemorrhage and coronary thrombi. Among the patients receiving t-PA, however, there was a greater frequency of platelet-rich (fibrin-poor) thrombi in the infarct-related coronary arteries (6 of 11 vs 4 of 25 thrombi; p = 0.02), more nonocclusive than occlusive thrombi (6 of 11 vs 4 of 25 thrombi; p = 0.02), and a lower frequency of myocardial rupture (left ventricular free wall or ventricular septum) (5 of 23 [22%] vs 18 of 38 [46%]; p = 0.045).

Aged↗
PubMed1990

Cardiac morphologic findings in patients with acute myocardial infarction treated with recombinant tissue plasminogen activator.

The hearts of 52 patients (aged 61 +/- 11 years, 34 men) who participated in the Thrombolysis in Myocardial Infarction (TIMI) Study and died from 5 hours to 260 days (median 2.7 days) after onset of chest pain were studied. One heart became available at cardiac transplantation. Of the 52 patients, 38 received recombinant tissue plasminogen activator (rt-PA) not followed by percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass grafting (CABG). Eight had PTCA, and 6 had CABG. The infarcts were hemorrhagic by gross inspection (with histologic confirmation) in 23 patients, nonhemorrhagic in 20, not visible grossly in 2 and, in 7, there was no myocardial necrosis by either gross or histologic examination.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Thrombosis↗
PubMed1990

The Thrombolysis in Myocardial Infarction (TIMI) Trial phase II: additional information and perspectives.

Given the many thrombolytic agents and the number of ways in which they can be combined with mechanical revascularization, the treatment of acute myocardial infarction has been the subject of active study and lively debate, which are likely to continue for some time. Several studies, including TIMI IIA (2,3,10,22), have suggested that immediate catheterization and angioplasty offer no clinical benefit and have a greater complication rate than a more delayed invasive strategy, but TIMI II (1) and SWIFT (16) trials have suggested that an even more conservative strategy of reserving catheterization and coronary angioplasty after thrombolytic therapy for patients with recurrent spontaneous or exercise-induced ischemia may be the most desirable approach for the majority of patients similar to those entered into these trials.

Angioplasty, Balloon, Coronary↗