Beneficial effects of amrinone-hydralazine combination on resting hemodynamics and exercise capacity in patients with severe congestive heart failure

Intravenous vasodilator therapy in congestive heart failure

The prevalence of congestive heart failure (CHF) is increasing in the US and worldwide, partly because patients are living longer. Treatment of CHF is mostly on an outpatient basis, but inpatient care is required for decompensated CHF, acute CHF or poor response to outpatient treatment. Control of symptoms is usually achieved by diuresis. Intravenous (IV) vasodilators are an important adjunct to the inpatient treatment of CHF. They work mainly by reducing the afterload on the myocardium although preload reduction also occurs. After clinical stabilisation, the goal is to switch to a maintenance oral regimen to be continued as outpatient therapy. The range of IV vasodilators available for inpatient treatment of CHF includes nitrates, phosphodiesterase inhibitors, dobutamine, morphine, ACE inhibitors, B-type natriuretic peptides and endothelin receptor antagonists. As each agent may have a different mechanism or site of action, each agent may affect preload, contractility or afterload to a different extent and it may be desirable to choose one over the other in a particular clinical setting. Examples of standard therapy include dobutamine, milrinone and nitroglycerin. Nesiritide, a B-type natriuretic peptide, is a newer vasodilator and US FDA approved for use in acute CHF. However, most studies with this agent have been in small numbers of patients with anecdotal findings. Larger studies are warranted to pinpoint the efficacy and adverse effects of this agent. It is primarily used to reduce the acuity of decompensated CHF on admission to hospital.Endothelin receptor antagonists show promise in the management of acute CHF, but continue to be investigational. Long-term data on their efficacy and safety are limited. None of the endothelin receptor antagonists are FDA approved for use in patients with CHF.

Inotropic therapy of the failing myocardium

The clinical syndrome of congestive heart failure remains a therapeutic dilemma and challenge for the physician in 1992. This is a disease process that appears to be increasing in frequency and continues to carry an unacceptably high mortality rate. For years it has been well recognized that the combination of digoxin, Lasix and vasodilator therapy improved symptoms in these patients and decreased hospitalization, but did not increase survival. It was not until 1986 that the combination of digoxin, Lasix, Isordil, and hydralazine was shown to increase survival. Further significant improvement in quality of life and survival has recently been established in three large clinical trials, and it is now safe to say that the standard of care for symptomatic congestive heart failure in 1992 is digoxin, furosemide, and an ACE inhibitor, with the survival trials favoring the ACE inhibitor enalapril. The IV inotropic drug dobutamine remains the mainstay of pharmacological therapy for the treatment of severely refractory heart failure. Unfortunately, the phosphodiesterase inhibitors--amrinone, milrinone, and enoximone--have demonstrated unacceptable clinical side effects and have been withdrawn from further clinical study. In spite of these promising developments, the mortality and morbidity of congestive heart failure remains unacceptably high, and continued investigation in the new fields of pharmacology and the pathophysiology of congestive heart failure still must be aggressively pursued.

Acute positive inotropic intervention: the phosphodiesterase inhibitors

Phosphodiesterase inhibitors that are selective for cAMP-specific cardiac and vascular PDE III comprise a new group of agents for the treatment of heart failure, which at present are limited to clinical shortterm intravenous use and research uses only. Although both intravenous amrinone and milrinone are FDA approved, only amrinone is available for general clinical use. Selective phosphodiesterase inhibition produces beneficial actions of positive inotropy and peripheral vasodilation that result from increased cardiac and vascular muscle concentrations of intracellular cAMP and ionic calcium. In addition, a positive lusitropic action (enhancement of cardiac relaxation) has been observed. Neither beta-adrenergic agonist activity nor inhibition of the sodium-potassium ATPase is produced by these agents. The magnitude of hemodynamic improvement generally exceeds that of the cardiac glycosides and is comparable with that of intravenous catecholamines such as dobutamine. The different pharmacodynamic profile of the PDE inhibitors is additive to the effects of cardiac glycosides, complementary and synergistic to the actions of catecholamines, and has been shown to have favorable effects on coronary hemodynamics. As a result there is continued enthusiasm for the short-term intravenous use of amrinone and potentially milrinone in the setting of acute heart failure resulting from systolic dysfunction (after myocardial infarction, open heart surgery, or infectious or toxic myocarditis), heart failure resulting from right ventricular systolic dysfunction, and when patients with severe heart failure await cardiac transplantation. Initiation of treatment with an intravenous bolus followed by a maintenance infusion provides prompt increases in stroke volume and cardiac output and simultaneous reductions in right and left ventricular filling pressures and systemic vascular resistance.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute haemodynamic effects of different doses of alifedrine in congestive heart failure

The haemodynamic effects of single oral doses of alifedrine 40 mg, 50 mg, 60 mg and placebo were compared in 30 patients with mild to moderate heart failure. Individual patients received either alifedrine 60 mg and placebo (15 patients) or alifedrine 40 mg and 50 mg (15 patients). All doses of alifedrine produced qualitatively similar haemodynamic responses, with maximum changes between 90 and 180 min after drug administration. The cardiac index was increased by +39%, +57%, and +50% by 40 mg, 50 mg and 60 mg, respectively. The increases were due to rises in stroke volume index (SVI) and in heart rate of +15%, +20% and +23%. Mean arterial blood pressure fell in a dose-related fashion, with a maximum fall of 11% by 120 min after 60 mg. The systemic vascular resistance index (SVRI) fell by 28%, 39% and 41%, and pulmonary vascular resistance index (PVRI) by 32%, 44% and 32% after 40 mg, 50 mg and 60 mg, respectively. The optimum dose appears to be 40 mg, which caused very little fall in blood pressure or increase in heart rate, yet significantly improved cardiac output. Alifedrine may have a place in the treatment of heart failure as an oral by active, positive inotropic agent.

Long-term oral therapy of congestive heart failure with phosphodiesterase inhibitors

The existing management of severe chronic congestive heart failure carries a dismal prognosis. Mortality over 6 months is 50% by some estimates. This fact, coupled with increasing concern for the safety and efficacy of the digitalis glycosides, has stimulated an intense search for new oral cardiotonic agents suitable for chronic administration. Despite the ability of many phosphodiesterase inhibiting agents to affect profound hemodynamic improvements acutely after oral or intravenous administration, none of the four agents here reviewed in 30 clinical trials has been adequately proven to provide benefit over conventional long-term therapy of severe heart failure. The four drugs to have undergone long-term clinical trials are amrinone, milrinone, enoximone (MDL 17043), and piroximone (MDL 19,025). For amrinone, inefficacy was revealed through carefully designed, placebo-controlled studies despite initial enthusiasm generated by open uncontrolled trials. Enoximone has suffered rapid attenuation of its hemodynamic effectiveness in most studies, and piroximone failed in its only long-term trial. Therefore, final judgment on most of these agents must await completion of controlled clinical trials, and any initial optimism stimulated by the current uncontrolled studies should be met with reservation.

Combination of positive inotropic and vasodilating substances in congestive heart failure

Therapy combining vasodilators and inotropic agents is considered to be one of the most powerful means of improving cardiac function in patients with congestive heart failure (CHF). The vasodilators enhance the effectiveness of inotropic agents by providing a reduction in preload and/or afterload. Inotropic drugs with different mechanisms of action, such as digitalis glycosides, ephedrine, dopamine, dobutamine, ibopamine, terbutaline, salbutamol, pirbuterol, prenalterol, amrinone, and milrinone, have been tested in combination with vasodilators with a predominant effect on preload (nitrates, molsidomine), with a predominant effect on afterload (hydralazine, nifedipine), or with a balanced action on both arterial and venous beds (nitroprusside, prazosin, captopril), showing positive results. The problem of the combination of digitalis glycosides and vasodilators with different sites of action has been considered by our group. In 42 patients with CHF, digoxin (DIG, 0.01 mg/kg intravenously) was tested in combination with molsidomine (MLS, 4 mg sublingually) (12 patients), a nitrate-like agent with a predominant vasodilating action on the capacitance vessels, nifedipine (NFP, 10 mg sublingually) (22 patients), a Ca2+ antagonist drug with a predominant action on the resistance vessels, and captopril (CPT, 25 mg orally) (8 patients), an ACE inhibitor with a balanced effect on both preload and afterload. The combination DIG plus MLS caused a reduction in left ventricular filling pressure (LVFP) greater than that achieved with either agent alone. The hemodynamic improvement was obtained without side effects, in spite of the striking fall in preload. We stress that this investigation was performed on patients with CHF following acute myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Intravenous use of amrinone for the treatment of the failing heart

Amrinone, a new nonadrenergic, nonglycosidic agent with combined positive inotropic and vasodilating properties, was approved recently for parenteral use in the treatment of left ventricular failure. Its mechanism of action is mediated primarily by selective phosphodiesterase fraction III inhibition, although at high doses alterations of calcium transport may occur. Acute hemodynamic changes produced by amrinone include augmentation of cardiac output and decreases in pulmonary capillary wedge pressure, right atrial pressure and systemic vascular resistance. Heart rate and blood pressure remain unaltered. Myocardial oxygen consumption declines concomitantly with the decrease in systolic wall tension. The efficacy of amrinone is comparable to that of dobutamine and dopamine. Synergistic interactions with catecholamines and vasodilators are described. Adverse effects are minimal, with dosage limited predominantly by decreases in filling pressures.

New positive inotropic drugs for the treatment of congestive heart failure

Positive inotropic agents can stimulate the severely depressed myocardium in late stages of heart failure. However, symptomatic benefits are only gained by improvement in the deranged peripheral circulation, which produces symptoms and limitations. In augmenting cardiac output and reducing filling pressures, the effects of positive inotropic agents and vasodilators are similar and additive, and the "contractile reserve of the heart" in response to inotropic stimulation may limit efficacy of these agents. Although symptomatic benefits occur in patients with severe heart failure after improvement in peripheral blood flow distribution, survival may not be altered, because this appears to be determined more by the amount of myocardial damage and its progression, and neither of these is affected by either inotropic agents or vasodilators. Indeed, in early stages of heart failure, therapy must be redirected toward preventing further myocardial cell loss rather than stimulating pump function.

Assessment of the inotropic and vasodilator effects of amrinone versus isoproterenol

The hemodynamic effects of graded-dose infusions of amrinone (maximal dose 30 micrograms/kg/min) (10 patients) and isoproterenol (maximum dose 4 micrograms/min) (11 patients) were assessed in patients with a range of left ventricular (LV) function. LV ejection fraction ranged from 0.13 to 0.77 (mean +/- standard deviation 0.47 +/- 0.23) among the patients who received amrinone and from 0.24 to 0.77 (mean 0.52 +/- 0.18) among those who received isoproterenol. Peak-dose amrinone produced a reduction in LV filling pressure (from 15 +/- 10 to 10 +/- 7 mm Hg, p less than 0.001), but no significant change in heart rate, cardiac output, mean aortic pressure, total systemic vascular resistance (TSVR) or LV dP/dt max. In contrast, peak-dose isoproterenol produced a similar reduction in LV filling pressure (from 17 +/- 12 to 13 +/- 13 mm Hg, p less than 0.05), but also caused increases in heart rate, cardiac output and LV dP/dt max and decreases in mean aortic pressure and TSVR (p less than 0.001). The absolute change in cardiac output and stroke volume correlated closely with the change in TSVR in response to amrinone (r = -0.90, p less than 0.001 and r = -0.84, p = 0.002, respectively), but not in response to isoproterenol. Although isoproterenol produced a marked increase in cardiac output and LV dP/dt max (not explained by heart rate changes alone) in all patients, amrinone produced an increase in cardiac output only in those with markedly elevated LV filling pressures (who had a reduction in TSVR), and an increase in LV dP/dt in a minority.

New concepts and drugs in the treatment of congestive heart failure

This article seeks to make clear the basic differences in the treatment of heart failure between therapeutic maneuvers that are aimed at improving the mechanical loading conditions of the heart and those that are aimed at augmenting the fundamental contractile or inotropic state of the myocardium. Emphasis is placed on recognizing that treatment expectations must be viewed within an age- or maturity-dependent framework, since a diminished margin of cardiocirculatory reserve exists in the smallest and youngest patients that limits the extent of benefit that may be derived from diverse treatment approaches.

Failure of low doses of amrinone to produce sustained hemodynamic improvement in patients with severe chronic congestive heart failure

Although amrinone produces acute hemodynamic improvement in patients with severe chronic congestive heart failure (CHF), it has not produced clinical benefits in long-term controlled trials. To determined if the administration of subtherapeutic doses of amrinone may account for its lack of efficacy in these studies, the dose requirements of the drug were investigated in 30 patients with severe CHF. Doses of 100 mg of oral amrinone produced moderate increases in cardiac index (0.35 liters/min/m2) and decreases in pulmonary capillary wedge pressure (6.8 mm Hg) and systemic vascular resistance (16%) (all p less than 0.01); these effects, however, were short-lived (less than 2.5 hours). Doses of 200 mg of oral amrinone produced marked increases in cardiac index (0.56 liters/min/m2) and substantial decreases in left ventricular filling pressure (9.9 mm Hg) and systemic vascular resistance (30%) (all p less than 0.01), and these effects persisted for longer than 4 hours. Only 4 patients showed hemodynamic responses with 100 mg of the drug that were sufficiently marked and long-lasting to merit chronic therapy, whereas 28 patients had such a response with the 200-mg dose. When 200 mg of amrinone was administered orally every 8 hours, sustained hemodynamic benefits were seen for 48 hours. However, 16 of 22 patients who received 600 mg of the drug daily for more than 1 week had intolerable adverse reactions that required drug withdrawal. In conclusion, hemodynamically effective doses of amrinone (600 mg/day) cannot be tolerated for long periods by most patients with severe chronic CHF.(ABSTRACT TRUNCATED AT 250 WORDS)

Echocardiographic evaluation of cardiovascular effects of amrinone

Amrinone, a new inotropic drug, was infused at a dosage of 2.5 mg/kg body weight in 14 patients affected by dilatative cardiomyopathy in New York Heart Association (NYHA) functional class III and IV. Cardiac index, mean arterial pressure, and some echocardiographic parameters were evaluated. Cardiac index (CI) increased from 2.03 +/- 0.24 to 2.82 +/- 0.43 1/min/m2 (p less than 0.001). Fractional shortening (FS) increased from 16.4 +/- 5.2 to 21.5 +/- 5.3% (p less than 0.05). End-diastolic and end-systolic diameters showed a significant reduction. Mean arterial pressure decreased from 90.7 +/- 88 to 87.3 +/- 8.4 mmHg (p less than 0.001), the end-systolic stress (ESS) decreased from 5.8 +/- 1 to 5.2 +/- 1 g/cm (p less than 0.001). Analyzing the relationship between FS and ESS, it was possible in some cases to suppose the presence of an important vasodilator effect of the drug. The afterload in 7 patients was therefore modified before and after infusion of the drug to analyze FS at the same levels of afterload. This was done to evaluate the vasodilator effect of amrinone. Examining the regression line of FS/ESS ratio it was possible to observe a predominant vasodilator effect in some patients, but in most, a sinergic action was noted. This may be useful for chronic treatment of congestive heart failure, reducing amrinone doses, and using it in association with other vasodilator drugs.

Oral amrinone for the treatment of chronic congestive heart failure: results of a multicenter randomized double-blind and placebo-controlled withdrawal study

A placebo-controlled study was employed to evaluate the effects of oral amrinone in patients with congestive heart failure. After a baseline period of at least 4 weeks of standard treatment for refractory congestive heart failure, oral amrinone was added to the treatment regimen of 173 patients. Patients were predominantly male (89%), aged 24 to 76 years (mean 54), with ischemic (52%) or idiopathic (37%) dilated cardiomyopathy, in New York Heart Association functional class II (40%), III (59%) and IV (1%) and having a mean (+/- standard deviation) left ventricular ejection fraction of 25 +/- 15%. Phase 1: After the addition of amrinone (113 +/- 33 mg three times daily), 52 patients (30%) showed a maximal increase in treadmill exercise time exceeding 2 minutes (Naughton protocol), 72 (42%) had a lesser increase, 24 (14%) developed limiting adverse reactions, 20 (12%) died and 5 dropped out of the study. Fifty-two "responders" (30%) who were free of limiting side effects and had a greater than 2 minute increase in exercise time were randomized in double-blind fashion to continued amrinone or switched to placebo (each plus standard treatment) for an additional 12 weeks. Phase 2: Comparison of 31 of these 52 responders who continued to receive amrinone with the remaining 21 randomized to placebo revealed no significant differences in vital signs, indexes of left ventricular size and function, systolic time intervals or maximal exercise time. Continued follow-up study of patients receiving either amrinone or placebo revealed decreases in exercise times of 7 and 10%, respectively (both p less than 0.05 compared with before randomization). Episodes of worsened congestive heart failure severe enough to mandate termination of double-blind treatment were as frequent in patients taking placebo (4[18%] of 21) as in those taking amrinone (4[13%] of 31; p = NS). The average symptom score and functional class of each treatment group remained comparable. Adverse effects such as gastrointestinal and central nervous system complaints were more common with amrinone treatment as were elevations of serum liver enzymes and reduced platelet counts. This large multicenter, randomized double-blind withdrawal study revealed no change in estimates of cardiac performance after the discontinuation of amrinone. These findings suggest that amrinone, in the dosages tested, does not importantly improve cardiac function beyond that provided by standard treatment with digoxin, diuretic drugs and vasodilators.

Amrinone therapy in patients with heart failure. Lack of improvement in functional capacity and left ventricular function at rest and during exercise

Short-term amrinone therapy has been shown to exert beneficial hemodynamic effects in patients with heart failure. To determine whether this improvement persists longer, the effects of maximally tolerated doses of amrinone on exercise duration, oxygen consumption, and left ventricular function and volumes were examined during maintenance therapy. After four weeks of amrinone therapy, 75 to 150 mg three times a day (mean 292 +/- 70 mg daily), treadmill exercise duration, maximal oxygen consumption, and functional class were unchanged from control values. Radionuclide-derived ejection fraction and end-diastolic and end-systolic volumes were not altered at rest or during maximal supine exercise. Similarly, significant changes in echocardiographic end-systolic and end-diastolic dimensions did not occur. This lack of clinical benefit on functional capacity and left ventricular function, together with frequent adverse reactions, will limit the application of amrinone in the treatment of heart failure. These findings are relevant to the investigation of amrinone-like derivations presently being studied for the treatment of heart failure. Before their release, these agents will require careful evaluation and demonstration of a therapeutic action during maintenance therapy, together with a low incidence of adverse reactions.

Non-additive positive inotropic effects of amrinone and ouabain on cat papillary muscles

Amrinone has been shown to produce haemodynamic benefits in digitalis-treated patients. Since amrinone is a positive inotropic agent on isolated heart muscle, these benefits may mean that amrinone increases the maximal ouabain-induced increase in force of contraction, without causing toxicity. We have therefore measured, in cat right ventricular papillary muscles, the inotropic effects of ouabain, amrinone alone and amrinone with a maximally effective, non-toxic ouabain concentration (2 X 10(-7) M). Ouabain is much more potent than amrinone (EC50-values: ouabain, 8 X 10(-8) M, amrinone, 1-2.8 X 10(-3) M). The highest amrinone concentration used (6 X 10(-3) M) produced a significantly lower increase in force of contraction than ouabain (2 X 10(-7) M) in the same muscles. After ouabain (2 X 10(-7) M) produced a stable effect, no further increase in force of contraction was observed with any amrinone concentration. Sustained arrhythmias were observed in five of six muscles at 3 X 10(-3) M amrinone with ouabain (2 X 10(-7) M), but in only one of these muscles with amrinone 3 X 10(-3) M alone. Since the positive inotropic effects of amrinone are not additive with those from a maximally effective ouabain concentration, the haemodynamic benefits seen in patients are probably due to non-cardiac effects of amrinone such as vasodilatation.

Improvement in exercise capacity despite cardiac deteriora tion: nonivasive assessment of long-term therapy with amrinone in severe heart failure

Seven patients with severe congestive heart failure (CHF) were treated with oral amrinone for a mean duration of 39 weeks (range 16 to 72). During the first week of therapy, exercise capacity as assessed on a treadmill using the Naughton protocol, increased substantially from 7.6 +/- 4.2 to 12.1 +/- 4.4 minutes (p less than 0.01). At an early period of follow-up (8 to 12 weeks), a further significant increase in exercise capacity to 14.7 +/- 5.0 minutes (p less than 0.05) was demonstrated, while at a later follow-up exercise capacity had decreased to 11.4 +/- 6.8 minutes (p less than 0.05). This was still significantly greater than prior to amrinone therapy (p less than 0.01). Left ventricular ejection fraction was increased from 14 +/- 4 to 19 +/- 4% (p less than 0.05) during the first week of therapy, but was not significantly different from control at the early and late periods of follow-up. Left ventricular end-diastolic dimension index increased from control value of 43 +/- 5 to 47 +/- 7 mm/m2 (p less than 0.01) at the late period of follow-up. Thus long-term amrinone therapy resulted in a substantial improvement in exercise capacity despite a slow, but progressive decline in cardiac performance.

Evaluation of a new bipyridine inotropic agent--milrinone--in patients with severe congestive heart failure

Milrinone, a derivative of amrinone, has nearly 20 times the inotropic potency of the parent compound and does not cause fever or thrombocytopenia in normal volunteers or in animals sensitive to amrinone. In 20 patients with severe congestive heart failure, intravenous milrinone resulted in significant decreases in left ventricular end-diastolic pressure (from 27 +/- 2 to 18 +/- 2 mm Hg), pulmonary wedge pressure, right atrial pressure, and systemic vascular resistance, as well as a slight reduction in mean arterial pressure. Significant increases occurred in cardiac index (from 1.9 +/- 0.1 to 2.9 +/- 0.2 liters per minute per square meter) and the peak positive first derivative of left ventricular pressure, with a slight increase in heart rate. Hemodynamic improvement was sustained during a 24-hour continuous infusion. Nineteen of the 20 patients subsequently received oral milrinone (29 +/- 2 mg per day) for up to 11 months (mean, 6.0 +/- 0.8), with sustained improvement in symptoms of heart failure. In 10 patients receiving long-term oral milrinone (greater than or equal to 6 months) radionuclide ventriculography showed continued responsiveness, with a 27 per cent increase in left ventricular ejection fraction after 7.5 mg of the drug. Four patients died after a mean of 4.8 months of therapy, and three patients with severe underlying coronary-artery disease and angina pectoris required additional antianginal therapy. No patient had fever, thrombocytopenia, gastrointestinal intolerance, or aggravation of ventricular ectopy. We conclude that milrinone shows promise for the longterm treatment of congestive heart failure.

Side effects of amrinone therapy

We gave intravenous amrinone to 40 patients in heart failure, and oral amrinone to 18 patients. Acute intravenous administration caused a significant reduction in mean blood pressure and this was severe enough to require correction by plasma infusion in five patients. Oral amrinone was accompanied by thrombocytopenia in 10 patients but no complications were associated with the low platelet count. Other potentially serious adverse effects were: abdominal pain (two patients), nausea and vomiting (three patients), jaundice (one patient), myositis (one patient), pulmonary infiltrates (two patients), and polyserositis (one patient). Less serious adverse effects observed were: splenomegaly, eosinophilia, fever, headache, reduced tear secretion, dry skin, and nail discoloration. The potentially severe adverse reactions with amrinone need to be weighed carefully against its benefits in the treatment of heart failure.

Acute haemodynamic comparison of amrinone and pirbuterol in chronic heart failure. Additional effects of isosorbide dinitrate

A randomised, within patient comparison was made in patients with severe chronic heart failure, to study the acute haemodynamic effects of oral agents which have inotropic and vasodilator properties. A non-glycosidic non-adrenergic positive inotropic agent with vasodilator properties (amrinone) was compared with a beta-agonist which has vasodilator and positive inotropic effects (pirbuterol). To assess whether combined treatment with a venodilator might be advantageous, the effect of adding isosorbide dinitrate was studied. Oral amrinone or pirbuterol were given in random order to each of 13 patients, on successive days, and oral isosorbide dinitrate was added after two-and-a-half hours. Control values before amrinone or pirbuterol were similar, and both drugs increased cardiac index while reducing left ventricular filling pressure, right atrial pressure, and systemic vascular resistance. Heart rate and blood pressure were unchanged. The magnitude of the changes caused by amrinone and pirbuterol were not significantly different. The addition of isosorbide dinitrate caused further falls in left ventricular filling pressure and right atrial pressures, and a fall in heart rate with each drug. Other measurements remained unchanged. Although amrinone and pirbuterol have different pharmacological properties, their acute haemodynamic effects in patients with chronic heart failure are indistinguishable.

Clinical experience with amrinone in patients with advanced congestive heart failure

To examine the efficacy of chronic amrinone therapy, the drug was administered to 12 patients with advanced congestive heart failure on average for 27.9 days. The majority of patients had a persistent increase in cardiac index and a persistent decrease in systemic vascular resistance. A decrease in pulmonary arterial diastolic pressure was observed after oral amrinone administration in three patients. However, changes in pulmonary arterial pressure were not consistent in response to intravenous administration of the drug. Thrombocytopenia occurred in four patients, hypogeusia was noted by three patients, and dysosmia developed in two patients. The cumulative survival of the amrinone patients was significantly poorer than that of a second group of patients with congestive heart failure having similar symptoms. These findings indicate that there is a subset of patients with congestive heart failure who do not benefit from chronic amrinone administration and that in such patients its use (especially when given concomitantly with potentially toxic and hypotensive drugs) should be extremely guarded.

Long-term amrinone therapy in patients with severe heart failure: drug-dependent hemodynamic benefits despite progression of disease

Six patients with severe congestive heart failure refractory to conventional therapy, including vasodilators, were treated with oral amrinone for a mean duration of 41 weeks (range 20 to 72 weeks). At initiation of therapy, the cardiac index increased from 1.74 +/- 0.31 to 2.62 +/- 0.52 (mean +/- SD) liters/min/m2 (p less than 0.01) and pulmonary capillary wedge pressure decreased from 26.5 +/- 3.5 to 19.5 +/- 5.4 mm Hg (p less than 0.05). Symptoms were alleviated and exercise capacity increased from 5.9 +/- 2.9 to 11.5 +/- 4.5 minutes (p less than 0.05). During long-term therapy, exercise capacity remained constants in three patients whereas it decreased in three others. All patients demonstrated an increase in heart size. Withdrawal of amrinone therapy precipitated severe symptoms at rest and hemodynamic deterioration in all patients. The cardiac index decreased from 1.87 +/- 0.49 to 1.32 +/- 0.30 liter/min/m2 (p less than 0.05) and pulmonary capillary wedge pressure rose from 20.6 +/- 2.9 to 28.8 +/- 5.6 mm Hg (p less than 0.05). These changes were reversed by reinstitution of therapy. Thus, amrinone-dependent hemodynamic benefits were demonstrated during long-term therapy without tachyphylaxis. In addition, progression of the underlying cardiac disease was observed in every patient.