Marc Klein

Effect of captopril on mortality and morbidity in patients with left ventricular dysfunction after myocardial infarction: Results of the survival and ventricular enlargement trial

BACKGROUND Left ventricular dilatation and dysfunction after myocardial infarction are major predictors of death. In experimental and clinical studies, longterm therapy with the angiotensin-converting--enzyme inhibitor captopril attenuated ventricular dilatation and remodeling. We investigated whether captopril could reduce morbidity and mortality in patients with left ventricular dysfunction after a myocardial infarction. METHODS Within 3 to 16 days after myocardial infarction, 2231 patients with ejection fractions of 40 percent or less but without overt heart failure or symptoms of myocardial ischemia were randomly assigned to receive doubleblind treatment with either placebo (1116 patients) or captopril (1115 patients) and were followed for an average of 42 months. RESULTS Mortality from all causes was significantly reduced in the captopril group (228 deaths, or 20 percent) as compared with the placebo group (275 deaths, or 25 percent); the reduction in risk was 19 percent (95 percent confidence interval, 3 to 32 percent; P = 0.019). In addition, the incidence of both fatal and nonfatal major cardiovascular events was consistently reduced in the captopril group. The reduction in risk was 21 percent (95 percent confidence interval, 5 to 35 percent; P = 0.014) for death from cardiovascular causes, 37 percent (95 percent confidence interval, 20 to 50 percent; P less than 0.001) for the development of severe heart failure, 22 percent (95 percent confidence interval, 4 to 37 percent; P = 0.019) for congestive heart failure requiring hospitalization, and 25 percent (95 percent confidence interval, 5 to 40 percent; P = 0.015) for recurrent myocardial infarction. CONCLUSIONS In patients with asymptomatic left ventricular dysfunction after myocardial infarction, long-term administration of captopril was associated with an improvement in survival and reduced morbidity and mortality due to major cardiovascular events. These benefits were observed in patients who received thrombolytic therapy, aspirin, or beta-blockers, as well as those who did not, suggesting that treatment with captopril leads to additional improvement in outcome among selected survivors of myocardial infarction.

Effect of Captopril on Mortality and Morbidity in Patients with Left Ventricular Dysfunction after Myocardial Infarction

BACKGROUND Left ventricular dilatation and dysfunction after myocardial infarction are major predictors of death. In experimental and clinical studies, longterm therapy with the angiotensin-converting--enzyme inhibitor captopril attenuated ventricular dilatation and remodeling. We investigated whether captopril could reduce morbidity and mortality in patients with left ventricular dysfunction after a myocardial infarction. METHODS Within 3 to 16 days after myocardial infarction, 2231 patients with ejection fractions of 40 percent or less but without overt heart failure or symptoms of myocardial ischemia were randomly assigned to receive doubleblind treatment with either placebo (1116 patients) or captopril (1115 patients) and were followed for an average of 42 months. RESULTS Mortality from all causes was significantly reduced in the captopril group (228 deaths, or 20 percent) as compared with the placebo group (275 deaths, or 25 percent); the reduction in risk was 19 percent (95 percent confidence interval, 3 to 32 percent; P = 0.019). In addition, the incidence of both fatal and nonfatal major cardiovascular events was consistently reduced in the captopril group. The reduction in risk was 21 percent (95 percent confidence interval, 5 to 35 percent; P = 0.014) for death from cardiovascular causes, 37 percent (95 percent confidence interval, 20 to 50 percent; P less than 0.001) for the development of severe heart failure, 22 percent (95 percent confidence interval, 4 to 37 percent; P = 0.019) for congestive heart failure requiring hospitalization, and 25 percent (95 percent confidence interval, 5 to 40 percent; P = 0.015) for recurrent myocardial infarction. CONCLUSIONS In patients with asymptomatic left ventricular dysfunction after myocardial infarction, long-term administration of captopril was associated with an improvement in survival and reduced morbidity and mortality due to major cardiovascular events. These benefits were observed in patients who received thrombolytic therapy, aspirin, or beta-blockers, as well as those who did not, suggesting that treatment with captopril leads to additional improvement in outcome among selected survivors of myocardial infarction.

Quantitative two-dimensional echocardiographic measurements are major predictors of adverse cardiovascular events after acute myocardial infarction. The protective effects of captopril.

BACKGROUND Left ventricular enlargement after myocardial infarction increases the likelihood of an adverse outcome. In an echocardiographic substudy of the Survival and Ventricular Enlargement (SAVE) Trial, we assessed whether captopril would attenuate progressive left ventricular enlargement in patients with left ventricular dysfunction after acute myocardial infarction and, if so, whether this would be associated with improved clinical outcome. METHODS AND RESULTS Two-dimensional transthoracic echocardiograms were obtained in 512 patients at a mean of 11.1 +/- 3.2 days after infarction and were repeated at 1 year in 420 survivors. Left ventricular size was assessed as left ventricular cavity areas at end diastole and end systole and left ventricular function as percent change in cavity area from end diastole to end systole. Patients were randomly assigned to placebo or captopril, and the incidence of adverse cardiovascular events consisting of cardiovascular death, heart failure requiring either hospitalization or open-label angiotensin-converting enzyme inhibitor therapy, and recurrent infarction were determined over a follow-up period averaging 3.0 +/- 0.6 years. Irrespective of treatment assignment, baseline left ventricular systolic area and percent change in area were strong predictors of cardiovascular mortality and adverse cardiovascular events. At 1 year, left ventricular end-diastolic and end-systolic areas were larger in the placebo than in the captopril group (P = .038, P = .015, respectively), and percent change in cavity area was greater in the captopril group (P = .005). One hundred eleven of the 420 1-year survivors with 1-year echo measurements (26.4%) experienced a major adverse cardiovascular event, and these patients had more than a threefold greater increase in left ventricular cavity areas than those with an uncomplicated course. Sixty-nine patients with adverse cardiovascular events were in the placebo group compared with 42 patients in the captopril-treated group (a risk reduction of 35%, P = .010). CONCLUSIONS Two-dimensional echocardiography provides important and independent prognostic information in patients after infarction. Left ventricular enlargement and function after infarction are associated with the development of adverse cardiac events. Attenuation of ventricular enlargement with captopril in these patients was associated with a reduction in adverse events. This study demonstrates the linkage between attenuation of left ventricular enlargement by captopril after infarction and improved clinical outcome.

A comparison of management patterns after acute myocardial infarction in Canada and the United States

BACKGROUND There are major differences in the organization of the health care systems in Canada and the United States. We hypothesized that these differences may be accompanied by differences in patient care. METHODS To test our hypothesis, we compared the treatment patterns for patients with acute myocardial infarction in 19 Canadian and 93 United States hospitals participating in the Survival and Ventricular Enlargement (SAVE) study, which tested the effectiveness of captopril in this population of patients after a myocardial infarction. RESULTS In Canada, 51 percent of the patients admitted to a participating coronary care unit had acute myocardial infarctions, as compared with only 35 percent in the United States (P < 0.001). Despite the similar clinical characteristics of the 1573 U.S. patients and 658 Canadian patients participating in the study, coronary arteriography was more commonly performed in the United States than in Canada (in 68 percent vs. 35 percent, P < 0.001), as were revascularization procedures before randomization (31 percent vs. 12 percent, P < 0.001). During an average follow-up of 42 months, these procedures were also performed more commonly in the United States than in Canada. These differences were not associated with any apparent difference in mortality (22 percent in Canada and 23 percent in the United States) or rate of reinfarction (14 percent in Canada and 13 percent in the United States), but there was a higher incidence of activity-limiting angina in Canada than in the United States (33 percent vs. 27 percent, P < 0.007). CONCLUSIONS The threshold for the admission of patients to a coronary care unit or for the use of invasive diagnostic and therapeutic interventions in the early and late periods after an infarction is higher in Canada than in the United States. This is not associated with any apparent difference in the rate of reinfarction or survival, but is associated with a higher frequency of activity-limiting angina.

Prognostic value of neurohumoral activation in patients with an acute myocardial infarction: effect of captopril.

OBJECTIVES This study attempted to evaluate whether neurohumoral activation at the time of hospital discharge in postinfarction patients helps to predict long-term prognosis and whether long-term therapy with the angiotensin-converting enzyme inhibitor captopril modifies this relation. BACKGROUND Neurohumoral activation persists at the time of hospital discharge in a large number of postinfarction patients. The Survival and Ventricular Enlargement (SAVE) study demonstrated that the angiotensin-converting enzyme inhibitor captopril improves survival and decreases the development of severe heart failure in patients with left ventricular dysfunction (left ventricular ejection fraction < or = 40%) but no overt postinfarction heart failure. METHODS In 534 patients in the SAVE study, plasma neurohormone levels were measured a mean of 12 days after infarction. Patients were then randomized to receive captopril or placebo and were followed up for a mean (+/- SD) of 38 +/- 6 months (range 24 to 55). The association between activation of plasma neurohormones at baseline and subsequent cardiovascular mortality or the development of heart failure was assessed with and without adjustment for other important prognostic factors. RESULTS By univariate analysis, activation of plasma renin activity and aldosterone, norepinephrine, atrial natriuretic peptide and arginine vasopressin levels were related to subsequent cardiovascular events, whereas epinephrine and dopamine levels were not. By multivariate analysis, only plasma renin activity (relative risk 1.6, 95% confidence interval [CI] 1.0 to 2.5) and atrial natriuretic peptide (relative risk 2.2, 95% CI 1.3 to 3.8) were independently predictive of cardiovascular mortality, whereas the other neurohormones were not. Only plasma renin activity and aldosterone, atrial natriuretic peptide and arginine vasopressin were independent predictors of the combined end points of cardiovascular mortality, development of severe heart failure or recurrent myocardial infarction. Except for 1-year cardiovascular mortality, the use of captopril did not significantly modify these relations. CONCLUSIONS Neurohumoral activation at the time of hospital discharge in postinfarction patients is an independent sign of poor prognosis. This is particularly true for plasma renin activity and atrial natriuretic peptide. Except for 1-year cardiovascular mortality, captopril does not significantly modify these relations.

Additive Beneficial Effects of Beta-Blockers to Angiotensin-Converting Enzyme Inhibitors in the Survival and Ventricular Enlargement (SAVE) Study

OBJECTIVES This study assessed whether treatment with a beta-adrenergic blocking agent in addition to the use of the angiotensin-converting enzyme (ACE) inhibitor captopril decreases cardiovascular mortality and morbidity in patients with asymptomatic left ventricular dysfunction after myocardial infarction (MI) and whether the presence of neurohumoral activation at the time of hospital discharge predicts the effects of beta-blocker treatment in these patients. BACKGROUND Both beta-blockers and ACE inhibitors have been shown to have beneficial effects in patients with left ventricular dysfunction but no overt heart failure after MI. These patients often have persistent neurohumoral activation at the time of hospital discharge, and one would expect that patients with activation of the sympathetic nervous system derive the most benefit from treatment with beta-blockers. However, beta-blockers are underutilized in this high risk group of patients, and it is unknown whether their beneficial effects are additive to those of ACE inhibitors. METHODS We performed a retrospective analysis of data from the Survival and Ventricular Enlargement (SAVE) study and its neurohumoral substudy. The relations between beta-blocker use at the time of randomization and neurohumoral activation and the subsequent development of cardiovascular events were analyzed by use of Cox proportional hazards models controlling for covariates. RESULTS After adjustment for baseline imbalances, beta-blocker use was associated with a significant reduction in risk of cardiovascular death (30%, 95% confidence interval [CI] 12% to 44%) and development of heart failure (21%, 95% CI 3% to 36%), but the reduction in recurrent MI (11%, 95% CI 13% to 31%) was not significant. These reductions were independent of the use of captopril. Beta-blockers were not found to have a greater effect in patients with neurohumoral activation at the time of hospital discharge. CONCLUSIONS The beneficial effects of beta-blocker use at the time of hospital discharge in patients with asymptomatic left ventricular dysfunction after MI appear to be additive to those of captopril and other interventions known to improve prognosis. Neurohumoral activation at the time of hospital discharge fails to identify those patients who will derive the greatest benefit from treatment with beta-blockers.

Activation of neurohumoral systems in postinfarction left ventricular dysfunction

OBJECTIVES This study was conducted to evaluate the degree of neurohumoral activation around the time of hospital discharge after myocardial infarction. BACKGROUND Because pharmacologic interventions that block the effects of neurohumoral activation improve the prognosis after infarction, we hypothesized that widespread neurohumoral activation persists in some patients until at least the time of hospital discharge and that the determinants of activation vary from one system to another. METHODS Five hundred nineteen patients in the Survival and Ventricular Enlargement Study (SAVE) had plasma neurohormones measured before randomization at a mean of 12 days after infarction. All patients had left ventricular dysfunction (left ventricular ejection fraction < or = 40%) but no overt heart failure. RESULTS Although all neurohormones except epinephrine were increased compared with values in age-matched control subjects, plasma norepinephrine (301 +/- 193 vs. 222 +/- 87 pg/ml, p < 0.001), renin activity (3.0 +/- 3.7 vs. 1.2 +/- 1.2 ng/ml per h, p < 0.001), arginine vasopressin (1.9 +/- 6.9 vs. 0.7 +/- 0.3 pg/ml, p < 0.001) and atrial natriuretic peptide (75 +/- 75 vs. 21 +/- 9 pg/ml, p < 0.001) values ranged from normal to very high, indicating a wide spectrum of neurohumoral activation. Activation of one system did not correlate with activation of another. The clinical and laboratory variables most closely associated with neurohumoral activation were Killip class, left ventricular ejection fraction, age and use of diuretic drugs. The association between neurohumoral activation and clinical and laboratory variables varied from one neurohormone to another. CONCLUSIONS Neurohumoral activation occurs in a significant proportion of patients at the time of hospital discharge after infarction. Which neurohormone is activated and which clinical and laboratory variables determine this activation vary from one neurohormone to another.

Activation of neurohumoral systems following acute myocardial infarction

Previous studies have indicated that patients with an acute myocardial infarction have marked activation of all neurohumoral systems on admission to the hospital. This activation begins to subside within the first 72 hours so that by 7-10 days, all plasma neurohormones have returned to normal. The only documented exceptions were found to occur in patients with left ventricular dysfunction and overt heart failure, where both plasma renin activity and atrial natriuretic peptide were increased, and in patients with left ventricular dysfunction but no overt heart failure, where only atrial natriuretic peptide was increased. Although these studies suggest that neurohumoral activation rarely occurs at the time of hospital discharge, they were small and may have missed an important subgroup of patients with persistent neurohumoral activation. In the Survival and Ventricular Enlargement (SAVE) study, 522 patients had plasma neurohumoral levels measured at a mean of 12 days postinfarction. All SAVE patients had left ventricular dysfunction (left ventricular ejection fraction less than or equal to 40%), but no overt heart failure. In this group of patients, all neurohumoral levels (plasma renin activity, norepinephrine, arginine vasopressin, and atrial natriuretic peptide) were found to be increased compared with age-matched control subjects. These results indicate that, in fact, a subgroup of patients without overt heart failure has persistent neurohumoral activation at the time of hospital discharge postinfarction, and that this activation involves several neurohumoral systems. Since patients with persistent neurohumoral activation postinfarction are likely those most at risk of developing complications and the ones most likely to benefit from pharmacologic interventions blunting the effects of neurohumoral activation, measurement of predischarge neurohumoral levels may be useful.

Synaptic augmentation by 5-HT at rested aplysia sensorimotor synapses: Independence of action potential prolongation

Short-term augmentation of synaptic transmission at sensory neuron synapses of Aplysia contributes to behavioral sensitization and is one of the current models for a cellular mechanism of learning. This neuromodulatory process, mediated at least in part by the facilitatory neurotransmitter serotonin (5-HT) acting through cAMP, has been thought to result largely from prolongation of the sensory neuron action potential (AP). The quantitative contribution of AP prolongation to synaptic augmentation was examined using a new culture preparation that is favorable for controlling the voltage at the presynaptic terminals. Preventing AP prolongation by using unvarying voltage-clamp commands in place of triggered APs did not reduce augmentation significantly, and pharmacological prolongation of APs caused by a high concentration of 5-HT led to a negligible increase in the synaptic response. Together with earlier evidence against the involvement of changes in Ca2+ current, these results suggest that synaptic augmentation may result from modulation of steps in the secretory process that lie distal to the flow of ion currents across the nerve terminal membrane.

Isoform Specificity of PKC Translocation in Living Aplysia Sensory Neurons and a Role for Ca2+-Dependent PKC APL I in the Induction of Intermediate-Term Facilitation

Protein kinase Cs (PKCs) are important effectors of synaptic plasticity. In Aplysia, there are two major phorbol ester-activated PKCs, Ca2+-activated PKC Apl I and Ca2+-independent PKC Apl II. Functional Apl II, but not Apl I, in sensory neurons is required for a form of short-term facilitation induced at sensorimotor synapses by the facilitatory transmitter serotonin (5-HT). Because PKCs are activated by translocating from the cytoplasm to the membrane, we used fluorescently tagged PKCs to determine the isoform and cell-type specificity of translocation in living Aplysia neurons. In Sf9 cells, low levels of diacylglycerol translocate Apl II, but not Apl I, which requires calcium for translocation at low concentrations of diacylglycerol. Accordingly, application of 5-HT to Aplysia sensory neurons in the absence of neuronal firing translocates Apl II, but not Apl I, consistent with the role of Apl II in short-term facilitation. This translocation is observed in sensory neurons, but not in motor neurons. Apl I translocates only if 5-HT is coupled to firing in the sensory neuron; firing alone is ineffective. Because combined 5-HT and firing are required for the induction of one type of intermediate-term facilitation at these synapses, we asked whether this form of synaptic plasticity involves activation of Apl I. We report here that dominant-negative Apl I, but not Apl II, blocks intermediate-term facilitation. Thus, different isoforms of PKC translocate under different conditions to mediate distinct types of synaptic plasticity: Ca2+-independent Apl II is involved in short-term facilitation, and Ca2+-dependent Apl I contributes to intermediate-term facilitation.