Lack of relationship between the short-term hemodynamic effects of captopril and subsequent clinical responses

Invasive hemodynamic monitoring the aftermath of the ESCAPE trial

The Swan-Ganz catheter was developed 35 to 40 years ago for intensive and cardiac care units to allow bedside placement and continuous monitoring and recording of right-sided heart, pulmonary artery, and wedge pressures and reasonably accurate determinations of cardiac output. Considerations for the clinical application of this balloon-tip, flow-directed, multilumen, thermodilution pulmonary artery catheter in the post-ESCAPE era are presented.

Gradual reactivation of vascular angiotensin I to angiotensin II conversion during chronic ACE inhibitor therapy in patients with diabetes mellitus

AIMS/HYPOTHESIS

In chronic heart failure there is gradual reactivation of vascular tissue angiotensin I (AI) to angiotensin II (AII) conversion over time in patients taking chronic ACE inhibitor therapy. However, it remains unknown whether the same overall phenomenon occurs in other patients taking chronic ACE inhibitor therapy, such as patients with type 2 diabetes mellitus.

METHODS

We studied 30 patients with type 2 diabetes mellitus (mean age 43.5 +/- 10.8 years), all of whom received lisinopril (20 mg/day) as part of their normal treatment. Over the course of the 18 month study, we made measurements at 0, 9 and 18 months. These measurements included plasma values for components of the renin-angiotensin-aldosterone system. In addition, we infused AI and AII into the brachial arteries of patients to assess vascular tissue AI to AII conversion.

RESULTS

There were no significant changes in plasma renin activity, ACE, AI, AII or aldosterone during the study. In contrast, vascular AI to AII conversion was significantly (p = 0.01) greater at 18 months than at 0 months. There was no change over time in the response to infused AII.

CONCLUSIONS/INTERPRETATION

We have shown in vivo that vascular tissue AI to AII conversion gradually increases over time in patients with type 2 diabetes being treated with lisinopril. Further studies are required to determine whether this reactivation detracts from the cardioprotective effects of chronic ACE inhibitor therapy in diabetic patients, and if so, how best to overcome it.

Gradual reactivation over time of vascular tissue angiotensin I to angiotensin II conversion during chronic lisinopril therapy in chronic heart failure

OBJECTIVES

This study was designed to fully characterize vascular tissue angiotensin I (AI)/angiotensin II (AII) conversion changes over time in vivo in humans during chronic angiotensin-converting enzyme (ACE) inhibitor therapy.

BACKGROUND

Plasma AII does not remain fully suppressed during chronic ACE inhibitor therapy. However, the plasma renin angiotensin system (RAS) might be dissociated from the vascular tissue RAS. We therefore set out to characterize the time course of vascular RAS reactivation during chronic ACE inhibitor therapy.

METHODS

Vascular AI/AII conversion was studied in patients with chronic heart failure (CHF) taking chronic lisinopril therapy by the differential infusion of AI and AII into the brachial artery. A cross-sectional study was done to see whether there were differences in vascular AI/AII conversion according to New York Heart Association (NYHA) class. A second longitudinal study followed 28 patients with NYHA I to II CHF serially over 18 months to see whether vascular ACE inhibition was progressively lost with time despite ACE inhibitor therapy. A third study examined whether increasing the dose of lisinopril affected subsequent vascular ACE inhibition.

RESULTS

In the cross-sectional study, vascular AI-to-AII conversion was significantly reduced in NYHA class III compared with class I/II (p < 0.05). In the longitudinal study, vascular ACE inhibition was significantly reduced at 18 months as compared with baseline (p < 0.001), suggesting gradual reactivation of vascular ACE in CHF over time. In the third study, tissue ACE inhibition could be restored by increasing the ACE inhibitor dose.

CONCLUSIONS

Vascular AI/AII conversion reactivates over time during chronic ACE inhibitor therapy even if the CHF disease process is clinically stable. It also occurs as the CHF disease process progresses. Even if vascular AI/AII conversion has reactivated, it can be suppressed by increasing the dose of the ACE inhibitor.

Comparison of the first dose response of fosinopril and captopril in congestive heart failure: a randomized, double-blind, placebo controlled study

The purpose of this study was to compare the safety and tolerability of recommended initial doses of fosinopril (FOS) with those of captopril (CAP), in diuretic-treated, salt depleted "high risk" patients with congestive heart failure. Thirty patients were randomized in a double blind fashion to receive a single dose of either FOS 10 mg, CAP 6.25 mg or placebo. CAP produced a significant early and brief fall in BP, while the first-dose hypotensive response with FOS did not differ significantly from placebo. Baseline plasma angiotensin converting enzyme (ACE) activity was similar in all groups. Only CAP showed an acute and significant fall in plasma ACE activity, whereas FOS and placebo did not change ACE activity. There was no correlation between mean arterial pressure or percentile change in mean arterial pressure and plasma ACE activity. Also no correlation was found between high or low ACE activity level and first dose hypotension. The practical importance of the results are: For patients with congestive heart failure. FOS and CAP have different effects on BP after the first dose, and this effect may be dependent on the plasma ACE activity level. FOS produces ACE inhibition and BP changes similar to placebo so it is the safer choice for the treatment of congestive heart failure.

Angiotensin-converting enzyme inhibitor dosages in elderly patients with heart failure

BACKGROUND

We sought to describe the dosages of angiotensin-converting enzyme (ACE) inhibitor prescribed to elderly patients with heart failure at hospital discharge, the factors associated with dosing level, and the association of these dosages with 1-year outcomes.

METHODS

Demographic, procedural, and medication data were collected retrospectively from medical records at 18 Connecticut hospitals. Information on mortality and readmission was obtained from the Health Care Financing Administration administrative databases. Dosages of ACE inhibitor were grouped into 3 categories: dosages recommended in practice guidelines or higher (target dose), dosages used in clinical trials but lower than guideline recommendations (subtarget dose), and dosages lower than those used in clinical trials (low dose).

RESULTS

A total of 554 patients, 65 years old or less with confirmed heart failure and systolic dysfunction, were prescribed an ACE inhibitor at discharge. Target, subtarget, and low doses were given in 19%, 63%, and 18% of the patients, respectively. Few demographic or clinical factors were related to lower dosages. Both subtarget and target doses of ACE inhibitors were associated with a significantly lower adjusted 1-year mortality (relative risk 0.67, P =.04; relative risk 0.51, P =.02, respectively) compared with low doses of ACE inhibitors.

CONCLUSIONS

In a representative elderly cohort of patients with heart failure with systolic dysfunction, the majority (82%) were discharged on doses of ACE inhibitors consistent with those used in clinical trials. We observed a dose-response relationship between higher doses and lower mortality. Future studies will need to determine whether this association is causal.

Effect of aspirin and ifetroban on skeletal muscle blood flow in patients with congestive heart failure treated with Enalapril. Ifetroban Study Group

OBJECTIVES

The purpose of this study was to determine the acute and chronic effects of cyclooxygenase inhibition with aspirin and thromboxane A2 receptor blockade with ifetroban on the chronic vasodilating effects of enalapril in the skeletal muscle circulation of patients with heart failure.

BACKGROUND

Angiotensin-converting enzyme inhibition and antiplatelet therapy with aspirin independently reduce the risk for subsequent nonfatal coronary events in survivors of myocardial infarction. The safety of the combined administration of angiotensin-converting enzyme inhibitors and aspirin has been questioned due to their divergent effects on the vascular synthesis of vasodilating prostaglandins.

METHODS

Forearm blood flow (ml/min/100 ml) at rest and during rhythmic handgrip exercise and after transient arterial occlusion was determined by strain gauge plethysmography before and 4 h and six weeks after combined administration of enalapril with either aspirin, ifetroban or placebo in a multicenter, double-blind, randomized trial of 62 patients with mild to moderate heart failure.

RESULTS

Before randomization, forearm hemodynamics were similar in the three treatment groups except for increased resting forearm blood flow and decreased resting forearm vascular resistance in the aspirin group when compared with the placebo group. After combined administration of enalapril and study drug for 4 h and six weeks, changes from prerandomization values of mean arterial pressure, forearm blood flow and forearm vascular resistance at rest, during handgrip exercise and after transient arterial occlusion did not differ among the three treatment groups.

CONCLUSIONS

These findings demonstrate that the vasodilating effects of enalapril in the skeletal muscle circulation of patients with heart failure are not critically dependent on prostaglandin pathways.

Evaluating the use of angiotensin-converting enzyme inhibitors for older nursing home residents with chronic heart failure

BACKGROUND

Despite their well noted therapeutic benefits for heart failure (HF), angiotensin-converting enzyme (ACE) inhibitors may be underprescribed and underdosed among older nursing home patients.

OBJECTIVES

To assess the use of ACE inhibitor therapy in older (> or =70 years) nursing home residents with systolic heart failure (HF).

DESIGN

A cross-sectional, retrospective analysis.

SETTING

Five long-term care facilities in Providence, Rhode Island.

SUBJECTS

Adults aged 70 years or older with left ventricular (LV) ejection fractions < or =40%.

MEASUREMENTS

New York Heart Association (NYHA) class, comorbid diseases, and cardiac medications with logistic regression analysis to clarify their bearing on the prescription of ACE inhibitors.

RESULTS

Of the 819 nursing home residents who were evaluated, 119 (24 men, 95 women) fulfilled exacting entry criteria, i.e., heart failure signs/symptoms and documented LV systolic dysfunction. Forty-one of these 119 (35%) older persons were receiving ACE inhibitor therapy, predominantly in doses (< or =50 mg captopril/day or < or =5 mg enalapril/ day) less than those of proven therapeutic efficacy. Compared with older residents not receiving ACE inhibitors, those receiving ACE inhibitors included fewer with NYHA Class I HF (0 vs 21%, P = .017), more men (58 vs 28%, P< or =.01), and more people with hypertension (61 vs 35%, P< or =.01). In contrast, diuretics were prescribed more frequently among those not receiving ACE inhibitors (83 vs 56%, P< or =.001).

CONCLUSIONS

ACE inhibitors are underprescribed and underdosed among elderly nursing home patients carefully screened to include systolic HF and no contraindications to the medication. ACE inhibitors are particularly underused in those elderly with NYHA Class I HF and in those receiving diuretics.

Maximal and submaximal exercise testing in heart failure

Although reduced exercise capacity is the main complaint of patients with congestive heart failure (CHF), the best method to measure it remains controversial. Peak VO2, obtained using maximal exercise testing, is the most accurate measure of maximal functional capacity. It is related to peak exercise cardiac output and is one of the most important independent variables for the prognostic assessment of patients with CHF. It has, however, a low sensitivity for measurement of changes induced by therapy and is poorly related to everyday physical activity, patient symptoms, and quality of life. The anerobic threshold may also be regarded as a parameter of maximal functional capacity. Its value is mainly indirect, because it shows that the patient is performing a maximal effort limited by the cardiovascular system. The VO2 kinetics at the start and at the end of exercise are probably more related to patient symptoms, but it is unresolved which protocols and parameters might best be used to study this aspect of exercise performance. Duration of a submaximal exercise at a constant work rate and the distance walked during a 6-min walking test are gaining wide popularity as parameters of submaximal performance. However, when these exams are carried out up to exhaustion in patients with severe functional limitation, they may involve attainment of the anerobic threshold and therefore their clinical meaning may be similar to the one of a maximal exercise test. Moreover, tests based on the assessment of submaximal exercise capacity have been useful for assessment of therapy in single-center trials but have been often inadequate in multicenter trials.

Differences in generalist and specialist physicians' knowledge and use of angiotensin-converting enzyme inhibitors for congestive heart failure

OBJECTIVE

To quantify the extent and determinants of underutilization of angiotensin-converting enzyme (ACE) inhibitors for patients with congestive heart failure, especially with respect to physician specialty and clinical indication.

DESIGN

Survey of a national systematic sample of physicians.

PARTICIPANTS

Five hundred family practitioners, 500 general internists, and 500 cardiologists.

MEASUREMENTS AND MAIN RESULTS

Physicians' choice of medications were determined for four hypothetical patients with left ventricular systolic dysfunction: (1) new-onset, symptomatic; (2) asymptomatic; (3) chronic heart failure, on digitalis and diuretic; and (4) asymptomatic, post-myocardial infarction. For each patient, randomized controlled trials have demonstrated that ACE inhibitors decrease mortality or the progression of symptoms. Among the 727 eligible physicians returning surveys (adjusted response rate 58%), approximately 90% used ACE inhibitors for patients with chronic heart failure who were already taking digitalis and a diuretic. However, family practitioners and general internists chose ACE inhibitors less frequently (p < or = .01) than cardiologists for the other indications. Respective rates of ACE inhibitor use for each simulated patient were new-onset, symptomatic (family practitioners 72%, general internists 76%, cardiologists 86%); asymptomatic (family practitioners 68%, general internists 78%, cardiologists 93%): and asymptomatic, postmyocardial infarction (family practitioners 58%, general internists 70%, cardiologists 94%). Compared with generalists, cardiologists were more likely [p < or = .05] to increase ACE inhibitors to a target dosage (45% vs 26%) and to tolerate systolic blood pressures of 90 mm Hg or less [43% vs 15%).

CONCLUSIONS

Compared with cardiologists, family practitioners and general internists probably underutilize ACE inhibitors, particularly among patients with decreased ejection fraction who are either asymptomatic or post-myocardial infarction. Educational efforts should focus on these indications and emphasise the dosages demonstrated to lower mortality and morbidity in the trials.

Relation of functional improvement in congestive heart failure after quinapril therapy to peripheral limitation

Angiotensin-converting enzyme inhibitors have been shown to increase maximal muscle blood flow in parallel to peak VO2 in patients with congestive heart failure (CHF). Whether this increase shifts factors limiting peak aerobic capacity from periphery (skeletal muscle or vessels) to central factors (cardiac or respiratory) is unknown. Comparison of peak oxygen consumption (VO2) obtained during leg cycling (VO2 leg) with peak VO2 obtained during combined leg cycling and arm cranking (VO2 arm + leg) allows determination of the relative role of central or peripheral factors. We compared VO2 leg with VO2 arm + leg before and after 3 months of therapy with quinapril 40 mg in 16 patients with CHF (age 53 +/- 13 years) due to left ventricular systolic dysfunction (ejection fraction 0.25 +/- 0.07). Before quinapril, VO2 arm + leg was significantly higher than VO2 leg (19.0 +/- 3.3 vs 16.9 +/- 3.8 ml/kg/min, p < 0.001), whereas after therapy these 2 values were similar (20.3 +/- 4.3 vs 21.0 +/- 4.3 ml/kg/min; p = NS), indicating that patients were no longer limited by peripheral factors. Besides, VO2 leg increase after therapy was higher in patients in whom difference between VO2 arm + leg and VO2 leg was the greatest (i.e., in patients who were initially more limited by peripheral factors). Simultaneously, calf peak reactive hyperemia and circumference significantly increased, indicating an improvement in vascular dilating capacity and an increase in skeletal muscle mass. No significant modification occurred in the forearm. Thus, patients who improved the most after 3 months of quinapril therapy were those who were initially limited by peripheral factors. The restricting role of these factors was reduced after quinapril therapy.

Do angiotensin-converting enzyme inhibitors prolong life in patients with heart failure treated in clinical practice?

Angiotensin converting enzyme (ACE) inhibitors have emerged as a significant advance in the treatment of heart failure; yet only a minority (i.e., 30% to 40%) of eligible patients are being treated with these drugs, and even among treated patients, the doses used in clinical practice are substantially lower than those used in the clinical trials that established the efficacy and safety of these agents. The preference for low doses is based on the belief that low and high doses exert similar benefits but that high doses produce more side effects. Yet, most studies indicate that large doses of ACE inhibitors produce greater hemodynamic and clinical effects than small doses, with no additional toxicity. However, it is uncertain whether the survival effects of these drugs are also related to dose. To address this question, a large multinational, double-blind clinical trial (Assessment of Treatment With Lisinopril and Survival [ATLAS]) was launched to compare the effects of low and high doses of the ACE inhibitor lisinopril on the survival of patients with heart failure. If the study demonstrates that large doses are needed to produce optimal effects on mortality, then the low dose strategies that are now widely used in clinical practice may be inadvertently nullifying the enormous potential benefits that ACE inhibitors might otherwise have on public health.

Effect of enalapril initiated early after acute myocardial infarction on heart failure parameters, with reference to clinical class and echocardiographic determinants. CONSENSUS II Multi-Echo Study Group

BACKGROUND AND HYPOTHESIS

Although the angiotensin-converting enzyme inhibitor enalapril has recently been shown to reduce mortality and the need for hospitalization in patients with left ventricular dysfunction and congestive heart failure, this drug was found to have no significant impact on short-term mortality after acute myocardial infarction (AMI) in the CONSENSUS II trial. The effect of enalapril initiated early after AMI on clinical and echocardiographic determinants of left ventricular (LV) function was studied in a subset of patients from CONSENSUS II.

METHODS

Symptoms and signs of heart failure were classified as NYHA and dyspnea classes. Echocardiography included LV end-systolic volumes (ESV) and end-diastolic volumes (EDV), as well as ejection fraction (EF), wall motion index (WMI), and mitral flow indices. In all, 428 patients were included and followed for an average of 5.1 months by serial examinations, starting 2-5 days after myocardial infarction (MI) and repeated after 1 month and at the completion of the study.

RESULTS

There was no beneficial effect of enalapril on clinically determined function. Changes (i.e., changes in NYHA class) in the functional status remained correlated with changes in echocardiographic determinants throughout the study in patients belonging to the placebo group: EDV index (r = 0.36, p = 0.002, ESV index (r = 0.49, p < 0.001), EF (r = -0.41, p < 0.001), and WMI (r = 0.29, p = 0.008). In a stepwise logistic regression model, the best baseline parameters to predict NYHA class at final visit in all patients were age (p = 0.014) and ESV index (p = 0.001).

CONCLUSION

Enalapril treatment for an average period of 5.1 months following MI resulted in no clinically significant beneficial effects on NYHA and dyspnea class. Changes in clinical function class were correlated with changes in echocardiographic determinants in placebo-treated patients, but not in patients given enalapril.

Failure of "effective" treatment for heart failure to improve normal customary activity

OBJECTIVES

To examine the effects of drug treatment on laboratory exercise tests in relation to measures of daily activity in patients with chronic heart failure.

SETTING

University teaching hospital.

SUBJECTS

18 patients with mild to moderate chronic heart failure (New York Heart Association functional class II-III) and 10 age matched healthy controls.

METHODS

Assessments were made before and after 12 weeks of vasodilator drug treatment. Exercise capacity was measured during two different types of treadmill exercise, one using a ramp protocol and the other a fixed work load. Corridor walk tests at three self selected speeds were also undertaken and measures of customary activity assessed from pedometer scores.

RESULTS

Exercise times were significantly increased from baseline (P < 0.01) with both treadmill protocols after 12 weeks of drug treatment, with a positive correlation between the duration of treadmill exercise for both protocols (r = 0.69, P < 0.01). Corridor walk tests of 100 m at a self selected slow speed also improved (P < 0.02) but these did not correlate with the changes in treadmill exercise time. The pedometer scores of the patients with heart failure were greatly reduced compared with those of the controls (258 (45) x 10(2) v 619 (67) x 10(2) steps/week, P < 0.001) and after 12 weeks of treatment were unchanged (261 (42) x 10(2) steps/week).

CONCLUSIONS

These data confirm the need to use different exercise protocols when assessing the benefits of drug treatment in patients with chronic heart failure. Treatments that seem effective with conventional laboratory based exercise tests may not improve daily activities. This may reflect a failure of apparently successful treatment and should be considered when interpreting clinical trials.

The management of heart failure: a matter of definition?

The term heart failure has become a label for more than one clinical entity. For many years heart failure has been used to denote patients with various heart diseases who have begun to suffer from fluid retention, pulmonary venous hypertension, or systemic venous hypertension, either alone or in combination. More recently, the term heart failure has been applied to the combination of effort intolerance and reduced left ventricular contractility due to ischemic heart disease or other myocardial disease. Comparison of the results of epidemiological studies and therapeutic trials is complicated by variation in the composition of the patient populations selected for study. Drug treatment of heart failure remains fairly empirical. Distinction should be made between immediate or prognostic benefits related to the etiological diagnosis, and benefits related specifically to prevention and relief of, for example, fluid retention, rhythm disturbances, or ventricular hypertrophy. The response of individual patients to several forms of drug treatment, including digoxin, ACE inhibitors, and beta-blockade, is unpredictable. Prospective identification of patients liable to respond well to these drugs is not yet possible, but would greatly assist the choice of treatment. At present, trial of therapy is required in each patient to establish benefit and to avoid long-term treatment of nonresponders.

The clinical pharmacology of ACE inhibitors: evidence for clinically relevant differences?

1. Potential differences among ACE inhibitors include pharmacokinetic and pharmacodynamic factors. The presence of a sulfhydryl group conferring antioxidant properties, the administration as a pro-drug to delay the onset and prolong the duration of haemodynamic effects, and the route of elimination are examples of possible differences. 2. Adverse effects of ACE inhibitors may be mediated by effects on bradykinin metabolism at tissue sites, which may be separable from haemodynamic responses mediated largely by angiotensin II withdrawal. 3. Clinically important differences between ACE inhibitors in their adverse event profile have yet to be proven. Evidence is emerging that plasma ACE inhibition and haemodynamic responses are separable, and this may indicate the potential for other organ-specific effects to differ among ACE inhibitors. 4. At present, however, the greatest distinguishing features for one compound vs another are the time to onset and the duration of action, which determine the frequency of administration.

Effect of cilazapril on regional left ventricular wall thickness and chamber dimension following acute myocardial infarction: in vivo assessment using MRI

The primary goal of the current study was to assess in situ, using magnetic resonance imaging, the effect of a new angiotensin-converting enzyme inhibitor, cilazapril, in reducing left ventricular remodeling after acute myocardial infarction. Three groups of animals were investigated: (1) sham-operated rats (n = 19); (2) infarcted rats receiving no treatment (n = 23); and (3) infarcted rats receiving cilazapril (100 mg/L drinking water, n = 20). Treatment with cilazapril began on the third day postocclusion and continued for 3 to 4 months. Myocardial infarction was produced by ligation of the left coronary artery, and electrocardiographic (ECG)-gated short-axis images were acquired 3 to 4 months later. Sham-operated animals were subjected to the same procedure but the left coronary artery was not ligated. From the image acquired in the middle of the left ventricle (equatorial slice), left ventricular wall thicknesses, chamber diameters, and surface area measurements of the cavities were determined. At autopsy examination, infarct size and tissue water content were determined. The results demonstrate that magnetic resonance imaging has the potential to assess in situ the alterations of left ventricular dimensions and mass after acute myocardial infarction and can be used to document the influence of therapeutic interventions. Cilazapril provided protection against the deleterious remodeling changes such as ventricular dilation and wall thinning consequent to acute myocardial infarction.

Vasodilators. A re-evaluation of their role in heart failure

Over the past 25 years, the concept of circulation in heart failure has evolved from that of a simple circuit with a weak pump and high pressures to a complex integrated system of cellular modification, cardiac compensation and systemic neurohumoral responses. The original model of cardiac afterload as the systemic vascular resistance has been refined to reflect the interdependence of preload and afterload and the central role of atrioventricular valve regurgitation. It is becoming increasingly apparent that the impact of vasodilator therapy far exceeds the direct haemodynamic effects on preload and afterload, and depends on the mechanism by which vasodilation is achieved, with increasing emphasis on those agents which oppose neurohumoral activation. The potential goals of therapy have broadened to include not only haemodynamic stabilisation through tailored therapy for patients referred with advanced heart failure, but also the prevention of disease progression for patients with asymptomatic ventricular dilation. As the different profiles of heart failure have come to be recognised, the purpose and design of vasodilator treatment must now be considered individually for each patient.

Application of cine nuclear magnetic resonance imaging for sequential evaluation of response to angiotensin-converting enzyme inhibitor therapy in dilated cardiomyopathy

Cine nuclear magnetic resonance (NMR) imaging was used to serially measure cardiovascular function in 17 patients with New York Heart Association class II or III heart failure and left ventricular ejection fraction less than or equal to 45% who were treated for 3 months with benazepril hydrochloride, a new angiotensin-converting enzyme inhibitor, while continuing treatment with diuretic agents and digoxin. Interobserver reproducibilities for ejection fraction (r = 0.94, SEE 3.3%), end-systolic volume (r = 0.98, SEE 10.6 ml), end-diastolic volume (r = 0.99, SEE 8.29 ml), end-systolic mass (r = 0.96, SEE 15.4 g), end-systolic wall stress (r = 0.91, SEE 10 dynes.s.cm-5) and end-systolic stress/volume ratio (r = 0.85, SEE 0.13) demonstrated applicability of cine NMR imaging for the serial assessment of cardiovascular function in response to pharmacologic interventions in patients with heart failure. During 12 weeks of treatment with benazepril, ejection fraction increased progressively from 29.7 +/- 2.2% (mean +/- SEM) to 36 +/- 2.2% (p less than 0.05), end-diastolic volume decreased from 166 +/- 14 to 158 +/- 12 ml (p = NS), end-systolic volume decreased from 118 +/- 12 to 106 +/- 11 ml (p less than 0.05), left ventricular mass decreased from 235 +/- 13 to 220 +/- 12 g (p less than 0.05), end-systolic wall stress decreased 29% from 90 +/- 5 to 64 +/- 5 dynes.s.cm-5 (p less than 0.05), end-systolic pressure decreased from 92.6 +/- 3.7 to 78.8 +/- 5.3 (p less than 0.05) and end-systolic stress/volume ratio, a load-independent index of contractility, decreased from 0.83 +/- 0.05 to 0.67 +/- 0.06 (p less than 0.05), demonstrating that improved ejection fraction is due to afterload reduction.

Effect of direct vasodilation with hydralazine versus angiotensin-converting enzyme inhibition with captopril on mortality in advanced heart failure: the Hy-C trial

To compare the benefit of angiotensin-converting enzyme inhibition and direct vasodilation on the prognosis of advanced heart failure, 117 patients evaluated for cardiac transplantation who had severe symptoms and abnormal hemodynamic status at rest were randomized to treatment with either captopril or hydralazine plus isosorbide dinitrate (Hy-C Trial). Comparable hemodynamic effects of the two regimens were sought by titrating vasodilator doses to match the hemodynamic status achieved with nitroprusside and diuretic agents, attempting to achieve a pulmonary capillary wedge pressure of 15 mm Hg and a systemic vascular resistance of 1,200 dynes.s.cm-5. Treatment with the alternate vasodilator was started because of poor hemodynamic response or side effects (40% of patients in the captopril group and 22% in the hydralazine group). Adequate hemodynamic response in patients with a serum sodium level less than 135 mg/dl was more likely with hydralazine than with captopril (71% vs. 33%, p = 0.04). Isosorbide dinitrate was prescribed in 88% of the hydralazine-treated patients and 84% of the captopril-treated patients. The hemodynamic improvements from each regimen were equivalent. After 8 +/- 7 months of follow-up, the actuarial 1-year survival rate was 81% in the captopril-treated patients and 51% in the hydralazine-treated patients (p = 0.05). The improved survival with captopril resulted from a lower rate of sudden death, which occurred in only 3 of 44 captopril-treated patients compared with 17 of 60 hydralazine-treated patients (p = 0.01). In the subset of patients who continued treatment with the initial vasodilator, results were similar to those for the entire treatment group.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of mitral regurgitation on the response to captopril therapy for congestive heart failure caused by idiopathic dilated cardiomyopathy

To assess the influence of mitral regurgitation (MR) on the response to captopril therapy for congestive heart failure (CHF), 30 patients with idiopathic dilated cardiomyopathy in New York Heart Association functional class III were studied. Left ventricular end-diastolic diameter and stroke volume were measured by Doppler echocardiography, and exercise tolerance by exercise testing before and at 1, 3 and 12 months after treatment. Patients were classified into 2 groups: those with (n = 14) and those without (n = 16) MR. No significant differences were observed between the 2 groups in pretreatment studies. Exercise tolerance increased significantly in the group with MR (p less than 0.001) during the year of follow-up, from 514 +/- 193 seconds at baseline study to 671 +/- 178 seconds (p less than 0.0005) at 1 month, 688 +/- 127 seconds (p less than 0.0005) at 3 months and 690 +/- 108 seconds (p less than 0.01) at 12 months. The group without MR had no significant changes. Stroke volume increased significantly only in the MR group during follow-up (p less than 0.01), changing from 43 +/- 9 ml at baseline study to 52 +/- 11 ml (p less than 0.01) at 1 and 49 +/- 11 ml (p less than 0.01) at 3 months. At 12 months the increase was not statistically significant. Left ventricular end-diastolic diameter decreased more in the group with than without MR, although the differences were not significant. Thus, the presence of dynamic MR appears to be an important factor in the therapeutic response to captopril therapy for CHF.

Angiotensin-converting enzyme inhibition and physical training in heart failure

A total of 12 patients (mean age +/- SEM 63 +/- 2.6 years) with moderate to severe heart failure (ejection fraction = 23 +/- 3.2%) were included in a placebo-controlled crossover trial. Patients were randomly allocated to 4 periods of 6 weeks each: placebo, placebo and physical training, lisinopril 10 mg daily, and lisinopril and physical training. The exercise time increased from 13.6 +/- 0.9 min with placebo to 15 +/- 1 min with training alone, and to 16.1 +/- 0.7 min with lisinopril and training. With lisinopril alone there was a non-significant increase in exercise time, to 14.5 +/- 0.6 min. Improvements in exercise time were accompanied by a similar increase in peak oxygen consumption. Overall, the most significant improvements in symptoms and indices of cardiorespiratory fitness were achieved with a combination of lisinopril and training. Thus physical training is not only a useful adjunct to the existing medical therapy for heart failure, but it may also provide symptomatic benefits in its own right.

Effect of medical therapy on survival of patients with dilated cardiomyopathy

Few studies have been conducted that focus on survival as the end point of medical therapy of CHF. No vigorous studies have been conducted in dogs. It is generally accepted that diuretic therapy is an essential component of the therapy of CHF in cardiomyopathic dogs. Significant symptomatic improvement is afforded by diuretics, and acute death may be prevented. In this context diuretics can be said to improve survival. However, diuretics do not alter the natural progression of cardiomyopathy and in this context do not favorably influence long-term survival. Digitalis glycosides have been shown in humans to improve various parameters of CHF in a subset of patients with either atrial fibrillation or third heart sounds. In dogs, these gallop heart rhythms due to third heart sounds are usually associated with myocardial failure due to dilated cardiomyopathy. In spite of symptomatic improvement, no study has demonstrated an unequivocal favorable effect of digoxin on survival of patients with dilated cardiomyopathy. Likewise, there is no convincing evidence of an adverse effect on survival. Newer, powerful inotropes, such as milrinone, often demonstrate impressive short-term improvements in left ventricular function, clinical signs, and exercise tolerance in patients with CHF. However, their long-term benefits are much less impressive, they are arrhythmogenic, and they have not been shown to prolong survival. In fact, long-term milrinone therapy in humans has had an unfavorable influence on mortality. Vasodilators offer the potential advantage of increasing left ventricular performance without an associated increase in myocardial oxygen demand and cardiac rhythm disturbances. The only vigorous survival study that unequivocally demonstrated improved survival of patients with advanced CHF due to myocardial failure, including dilated cardiomyopathy, was the Consensus Trial. Survival of patients receiving enalapril was significantly better than those receiving placebo. In fact, the trial was stopped prematurely by the ethical review committee when it became obvious that the results favored the enalapril group. Although the use of beta-adrenergic blocking drugs in cardiomyopathic patients with CHF is controversial and associated with a risk of short-term deterioration of left ventricular function, their use in human medicine is gaining acceptance. Although hemodynamic and clinical evidence of improvement has been demonstrated along with withdrawal-associated deterioration, the only study purporting a beneficial effect on survival used retrospective controls.(ABSTRACT TRUNCATED AT 400 WORDS)

Differences in first dose response to angiotensin converting enzyme inhibition in congestive heart failure: a placebo controlled study

OBJECTIVE

To compare the first dose responses to low dose angiotensin converting enzyme inhibitors (captopril, enalapril, and perindopril) in elderly patients with stable chronic heart failure.

DESIGN

Double blind, randomised, placebo controlled, parallel, group prospective study of elderly patients with stable chronic heart failure.

SETTING

General hospital in-patient admissions for supervised diuretic withdrawal (24-48 hours) and the introduction of angiotensin converting enzyme inhibitor therapy.

PATIENTS

48 unselected elderly (58-85 years) patients with symptomatic but stable chronic heart failure (New York Heart Association grades II-IV) confirmed by clinical history, examination, and cardiological investigations. Patients gave their written and informed consent to receive their initial treatment under double blind conditions; blood pressure was monitored and blood samples taken to measure the pharmacokinetic and neurohormonal responses.

INTERVENTION

Patients were randomised to receive a daily oral dose of placebo, captopril (6.25 mg), enalapril (2.5 mg), or perindopril (2 mg).

MAIN OUTCOME MEASURES

Blood pressure and heart rate responses, drug concentration, and plasma renin and ACE activities. Differences between treatment groups were analysed by analysis of variance.

RESULTS

The four randomised groups of patients had similar age, severity of heart failure (NYHA class), pretreatment diuretic dosage, plasma renin activity, and serum electrolyte state. Placebo treatment caused a modest but significant diurnal fall in blood pressure. Captopril produced a significant early (1.5 hours) and brief fall in blood pressure. The blood pressure fall with enalapril was later (4-10 hours), longer lasting, and was associated with significant slowing of supine heart rate. Though perindopril produced a similar plasma ACE inhibition to that produced by enalapril, it only caused changes in blood pressure that were similar to those caused by placebo.

CONCLUSIONS

This controlled study is the first to indicate a qualitative difference in the acute response to angiotensin converting enzyme inhibitors with similar structure and metabolism (that is, enalapril and perindopril). Low dose perindopril seems to be less likely to cause hypotension in patients with heart failure. The explanation for the differences is unclear but may reflect differential effects on local tissue angiotensin generation.

Exercise capability in heart failure: is cardiac output important after all?

The exercise capability of 39 patients with severe chronic heart failure was assessed in several ways and compared with measurements of cardiac output. The relation between cardiac index and exercise tolerance measured on a treadmill was poor (r = 0.191, p = 0.245). However, exercise tolerance measured with a series of self-paced corridor walk tests showed moderate correlations with cardiac index (r = -0.404, p = 0.015 to r = -0.516, p = 0.001) and customary activity assessed by step counting correlated better with cardiac index (r = 0.537, p less than 0.001). Cardiac output therefore seems to be a factor determining patients' exercise capability when they choose their own walking speed but not when they undergo formal treadmill tests in the laboratory.

Sustained reduction in valvular regurgitation and atrial volumes with tailored vasodilator therapy in advanced congestive heart failure secondary to dilated (ischemic or idiopathic) cardiomyopathy

Afterload reduction therapy can acutely improve hemodynamic function in patients with advanced heart failure; however, it is unknown if initial reductions in mitral and tricuspid regurgitation and atrial volumes can be sustained with oral therapy. Atrial volumes and atrioventricular valve regurgitation were measured using 2-dimensional and Doppler echocardiography with color-flow imaging in 14 patients with dilated heart failure (ejection fraction 17 +/- 4%) before and after 3 +/- 1 days of intensive vasodilator and diuretic therapy tailored to hemodynamic goals. Echocardiography was repeated again after 6 +/- 2 months on oral vasodilators and a flexible diuretic regimen. Acute therapy reduced systemic vascular resistance from 1,760 +/- 460 to 1,010 +/- 310 dynes.s.cm-5, pulmonary artery wedge pressure from 30 +/- 5 to 17 +/- 4 mm Hg, and right atrial pressure from 13 +/- 5 to 7 +/- 3 mm Hg, and led to a 61% increase in stroke volume (from 36 +/- 10 to 58 +/- 14 ml) (p less than 0.01). Mitral and tricuspid regurgitation, determined by color-flow fraction, initially decreased from 0.34 +/- 0.17 to 0.20 +/- 0.20 and from 0.33 +/- 0.15 to 0.13 +/- 0.13, respectively (p less than 0.001). This reduction was sustained at 6 months. Significant decreases occurred with acute therapy, with further reductions at 6 months in both mean left atrial volume (from 100 +/- 25 to 80 +/- 19 to 65 +/- 15 cm3) and right atrial volume (from 85 +/- 23 to 64 +/- 23 to 52 +/- 14 cm3) (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Tissue and plasma angiotensin converting enzyme and the response to ACE inhibitor drugs

1. There is a body of circumstantial and direct evidence supporting the existence and functional importance of a tissue based RAS at a variety of sites. 2. The relation between circulatory and tissue based systems is complex. The relative importance of the two in determining haemodynamic effects is unknown. 3. Despite the wide range of ACE inhibitors already available, it remains unclear whether there are genuine differences related to tissue specificity. 4. Pathological states such as chronic cardiac failure need to be explored with regard to the contribution of tissue based ACE activities in generating acute and chronic haemodynamic responses to ACE inhibitors. 5. The role of tissue vs plasma ACE activity may be clarified by study of the relation between drug concentration and haemodynamic effect, provided that the temporal dissociation is examined and linked to circulating and tissue based changes in ACE activity, angiotensin peptides and sympathetic hormones.

Importance of hemodynamic response to therapy in predicting survival with ejection fraction less than or equal to 20% secondary to ischemic or nonischemic dilated cardiomyopathy

To identify patients with left ventricular ejection fractions less than 20% who are likely to survive on tailored medical therapy after referral to transplantation, this study of 152 patients addressed the hypotheses that (1) severely elevated filling pressures initially measured at referral would not necessarily predict poor outcome, (2) survival would be best when low pulmonary wedge pressures could be achieved with therapy tailored for hemodynamic goals, and (3) coronary artery disease would be an independent risk factor for early mortality. Despite an average initial ejection fraction of 0.15, cardiac index of 2.0 liters/min/m2 and pulmonary artery wedge pressure of 28 mm Hg, the actuarial survival with tailored therapy was 63% at 1 year, with 34 of 41 (83%) deaths occurring suddenly. Survival was not related to initial filling pressure elevation, but was best predicted by the pulmonary artery wedge pressures during therapy; patients achieving pressure of less than or equal to 16 mm Hg had 1-year survival of 83 vs 38% (p = 0.0001). The other independent predictors were serum sodium and coronary artery disease. Patients with high filling pressures during therapy and coronary artery disease had 21% survival at 1 year. Survival after referral to transplantation with an ejection fraction less than or equal to 20% is better than previously described. Patients in whom left ventricular filling pressures cannot be adequately reduced by tailored therapy, particularly if coronary artery disease is present, should be considered for early transplantation.

Potential role of the tissue renin-angiotensin system in the pathophysiology of congestive heart failure

The circulating renin-angiotensin system (RAS) plays an important role in the maintenance of cardiovascular homeostasis. It has recently been demonstrated that endogenous RAS exist in target tissues that are important in cardiovascular regulation. This article reviews the multiple effects of angiotensin II in target tissues, the evidence for the presence of functional tissue RAS and the data that suggest a role for these tissue RAS in the pathophysiology of heart failure. Activation of circulating neurohormones is predictive of worsened survival in heart failure; however, cardiac and renal tissue RAS activities are also increased in the compensated stage of heart failure, when plasma renin-angiotensin activity is normal. It is hypothesized that the plasma RAS maintains circulatory homeostasis during acute cardiac decompensation, while changes in tissue RAS contribute to homeostatic responses during chronic sustained cardiac impairment. This concept of different functions of circulating and tissue RAS in the pathophysiology of heart failure may have important pharmacologic implications.

Endocrinologic Warfare: The Role of Angiotensin-Converting Enzyme Inhibitors in Congestive Heart Failure

The angiotensin-converting enzyme (ACE) inhibitors represent the gold standard of vasodilator therapy for congestive heart failure through blunting of the endocrinologic manifestations of heart failure. The future role of these agents may be in the asymptomatic and mild stages of heart failure. ACE inhibitors have been shown to decrease morbidity and mortality with the natural history of this disease being altered. The future will bring many new ACE inhibitors to market, with the challenge for physicians and pharmacists to understand the important distinctions of each specific agent. © 1990 by W.B. Saunders Company.

Duration and reproducibility of initial hemodynamic effects of flosequinan in patients with congestive heart failure

The duration and reproducibility of hemodynamic effects of flosequian, a direct-acting, balanced-type vasodilator, were studied in 19 heart failure patients (NYHA class 3.0 +/- 0.7) receiving 100 mg orally (day 1), placebo (day 2), and again 100 mg (day 3). Flosequinan immediately reduced systemic and pulmonary resistance (23% and 35%, respectively, at 60-90 minutes postdrug) and decreased pulmonary wedge, right atrial, mean pulmonary artery, and mean arterial pressure by 38%, 50%, 25%, and 7%, respectively. Concomitantly, cardiac output, and stroke volume and work increased by 26%, 20%, and 22%, respectively. Most hemodynamic effects persisted for 48 hours. In contrast, changes in pulmonary wedge and arterial pressures, stroke volume, and stroke work only lasted for 2-12 hours. Maximum absolute changes on day 3 were generally comparable with first-dose effects with, again, long-lasting effects on systemic resistance and cardiac output. However, changes in pulmonary artery, wedge, and resistance were significantly shorter than after first dose administration. These data indicate sustained and reproducible arterial dilating effects of flosequinan, but less pronounced and shorter lasting pulmonary arterial and venodilator properties.

Captopril in children with dilated cardiomyopathy: acute and long-term effects in a prospective study of hemodynamic and hormonal effects

Hemodynamic and hormonal effects of captopril were prospectively studied in 12 children (median age 5.8 years, range 4 weeks to 15 years) with dilated cardiomyopathy. A mean dose of 1.83 mg captopril/kg body weight was administered in three or four single doses depending on age. Left ventricular volume, ejection fraction (EF), cardiac index (CI), and systemic vascular resistance (SVR) were noninvasively determined by two-dimensional (2D) and Doppler echocardiography before and 2 days and 3 months after the onset of treatment. Blood pressure and heart rate were recorded as well. Additionally, on the day hemodynamic measurements were made, plasma renin activity (PRA), serum aldosterone, and plasma atrial natriuretic peptide (ANP) concentrations were determined. Plasma catecholamines were measured before and 2 days after captopril treatment. Concomitant medication was kept constant during the short-term phase of captopril treatment. During long-term therapy, diuretics were reduced according to the clinical status. Stroke volume (SVI) (-7%), end-systolic (ESVI) (-31%), and end-diastolic (EDVI) (-21%) volume indexes were significantly reduced (p less than 0.05) during short- and long-term therapy. The remaining hemodynamic parameters showed only minor, statistically not significant, changes. During short-term therapy, median serum aldosterone levels fell from 138-88.5 pg/ml (p less than 0.05), and plasma ANP decreased from 144-94 pg/ml (p less than 0.05). After 3 months these effects were less marked and statistically no longer significant. Changes in PRA and plasma catecholamines were not statistically significant at any time.(ABSTRACT TRUNCATED AT 250 WORDS)

Vasodilator therapy without converting-enzyme inhibition in congestive heart failure--usefulness and limitations

Despite a well-established rationale for pharmacologically induced arterial and venous vasodilatation in congestive heart failure, the clinical usefulness of long-term vasodilator therapy without concomitant converting-enzyme inhibition generally has been disappointing. With the exception of nitrates and, possibly, the combination of nitrates and hydralazine, the use of converting-enzyme inhibitors in many aspects appears preferable in the majority of patients. This article reviews the pathophysiology of inappropriate vasoconstriction in heart failure, the cellular mode of action of the various vasodilators, hemodynamic effects with respect to the peripheral site of action, clinical usefulness and limitations of different vasodilators, and the various determinants of clinical efficacy. Finally, an attempt is made to assess when and how to introduce vasodilator treatment with and without concomitant ACE inhibition.

Congestive heart failure--advances in treatment. Hemodynamic studies--their uses and limitations

Hemodynamic studies are useful in the diagnosis of the pathophysiologic mechanisms of pump failure and low output state in patients with acute heart failure. Hemodynamic monitoring is extremely useful for the appropriate manipulation of the vasoactive drugs to optimize hemodynamic and clinical improvement of patients with acute heart failure and to stabilize patients with severe refractory or unstable chronic heart failure. Determinations of the hemodynamic indexes of left ventricular function during hemodynamic studies also provide information regarding prognosis of patients with acute or chronic heart failure. In patients with stable chronic heart failure, correlations between the changes in hemodynamics after initiation of vasodilator therapy and subsequent changes in the clinical status and exercise tolerance are poor; thus, the value of hemodynamic studies for vasodilator therapy in patients with stable chronic heart failure is limited.

Comparison of enalapril versus digoxin for congestive heart failure

A multicenter, randomized, double-blind, parallel-group trial was conducted to compare the effects of enalapril and digoxin on clinical signs and symptoms, as well as exercise capacity, in 142 patients with congestive heart failure classified as mild to severe (New York Heart Association functional classes II to IV). The patients received optimal treatment with digitalis and diuretics for 2 to 4 weeks. Thereafter, they were randomly assigned to receive either enalapril plus diuretics (n = 72) or digoxin plus diuretics (n = 70). After 8 weeks of treatment, a significant improvement in classification was observed in 22 of 63 patients (35%) in the enalapril group and in 17 of 61 (28%) in the digoxin group (difference not significant [NS]). Similarly, duration of exercise increased in both groups (p less than 0.005; p = NS between groups). Blood pressures decreased in the enalapril group (from 129 +/- 19/80 +/- 10 to 121 +/- 20/78 +/- 11 mm Hg; p less than 0.001), but not in the digoxin group (from 134 +/- 19/82 +/- 12 to 138 +/- 19/85 +/- 10 mm Hg; NS). Serum creatinine and electrolytes did not exhibit any significant change from baseline values, except for serum potassium, which increased slightly in the enalapril group (from 4.24 +/- 0.48 to 4.43 +/- 0.49 mmol/liter; p less than 0.05) and decreased slightly in the digoxin group (from 4.28 +/- 0.47 to 4.18 +/- 0.40 mmol/liter; p less than 0.05). Adverse events were reported in 13 patients (5 withdrawals) in the enalapril group and in 7 patients (2 withdrawals) in the digoxin group (p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)