Contribution of reduced mitral regurgitant volume to vasodilator effect in severe left ventricular failure secondary to coronary artery disease or idiopathic dilated cardiomyopathy

The Role of Arterial Hypertension in Mitral Valve Regurgitation

PURPOSE OF REVIEW

To review medical literature for evidence of association between hypertension and mitral regurgitation (MR) and summarize potential favorable effects of antihypertensive drugs on MR natural history and treatment.

RECENT FINDINGS

Hypertension and MR are common diseases affecting a large proportion of the general population. Contemporary evidence suggests that hypertension may worsen the progression and prognosis of MR through augmented mechanical stress and increased regurgitation volume. Renin-angiotensin axis inhibitors, beta-blockers, and vasodilators have been tested in order to prevent or decrease primary or secondary MR. Although antihypertensive agents may improve hemodynamic parameters and left ventricular remodeling in primary MR, there is no strong evidence of benefit on clinical outcomes. On the other hand, a beneficial effect of these drugs on secondary MR is better established. Moreover, there are no studies evaluating a possible benefit of lower blood pressure targets in MR. Randomized controlled trials are warranted to elucidate the precise role of antihypertensive therapy on treatment of MR.

Renin-angiotensin system inhibitors in patients with or without ischaemic mitral regurgitation after acute myocardial infarction

Objective

Little is known about the long-term effects of renin–angiotensin system inhibitors (RASI) on cardiovascular events in patients after acute myocardial infarction (AMI) with ischaemic mitral regurgitation (IMR). The purpose of this study was to investigate the association of RASI with the incidence of adverse cardiac events in patients with or without IMR after AMI.

Methods

We reviewed charts of 1208 consecutive patients admitted with AMI who underwent emergency coronary angiography between 2000 and 2012. After excluding patients who died within 30 days, 551 patients were diagnosed to have mild or greater MR by transthoracic echocardiography (patients with IMR); the remaining 505 patients had no or trivial MR (non-IMR patients).

Results

Of the study patients, 395 (72%) patients with IMR and 403 (80%) non-IMR patients received RASI. Survival analysis showed that freedom from cardiac death and the composite of cardiac death and heart failure (HF) was significantly higher in patients with IMR receiving RASI than in those not receiving RASI (P<0.001 and P<0.001, respectively). Moreover, adjusted survival analysis using the inverse probability treatment weighting method showed a significant association of RASI therapy with reduced cardiac death (P=0.010) and the composite of cardiac death and HF (P=0.044) in patients with IMR. However, in non-IMR patients, there were no significant associations between RASI therapy and the outcome measures.

Conclusions

RASI therapy was associated with a lower incidence of adverse cardiac events in patients with IMR after AMI, but not in patients without IMR.

Comparative effectiveness of Mitraclip plus medical therapy versus medical therapy alone in high-risk surgical patients: a comprehensive review

In recent years, Mitraclip has become available as a treatment option for mitral regurgitation in high-risk surgical patients. Focusing on the incremental effectiveness of Mitraclip versus the current standard of care, this article provides a comparative review of the evidence on Mitraclip and standard medical therapy (MT) in high-risk mitral regurgitation patients. Evidence was retrieved from seven major databases. Results suggest that Mitraclip presents a high safety profile and a good middle-term effectiveness performance. Evidence on long-term effectiveness is limited both for Mitraclip and MT. Few studies allow a comparison with MT and comparative results on different endpoints are mixed. Therefore, the available evidence does not conclusively inform whether or under which circumstances Mitraclip should be preferred over MT in the treatment of high-risk patients. Head-to-head real-world studies would be needed, as they would provide great and timely insights to support policy decisions when medical devices are at stake.

Reduction in mitral regurgitation during therapy guided by measured filling pressures in the ESCAPE trial

BACKGROUND

Dynamic mitral regurgitation (MR) contributes to decompensation in chronic dilated heart failure. Reduction of MR was the primary physiological end point in the ESCAPE trial, which compared acute therapy guided by jugular venous pressure, edema, and weight (CLIN) with therapy guided additionally by pulmonary artery catheters (PAC) toward pulmonary wedge pressure

METHODS AND RESULTS

Patients were randomized to PAC or CLIN during hospitalization with chronic heart failure and mean left ventricular ejection fraction 20%, and at least 1 symptom and 1 sign of congestion. MR and mitral flow patterns, measured blinded to therapy and timepoint, were available at baseline and discharge in 133 patients, and at 3 months in 104 patients. Changes in MR and related transmitral flow patterns were compared between PAC and CLIN patients. Jugular venous pressure, edema, and weights decreased similarly during therapy in the hospital for both groups. In PAC but not in CLIN patients, MR jet area, MR/left atrial area ratio, and E velocity were each significantly reduced and deceleration time increased by discharge. By 3 months, patients had clinical evidence of increased jugular venous pressure, edema, and weight since discharge, reaching significance in the PAC arm, and the change in MR was no longer different between the 2 groups, although the change in E velocity remained greater in PAC patients.

CONCLUSIONS

During hospitalization, therapy guided by PAC to reduce left-sided pressures improved MR and related filling patterns more than therapy guided clinically by evidence of systemic venous congestion. This early reduction did not translate into improved outcomes out of the hospital, where volume status reverted toward baseline.

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Key Words

• hemodynamics
• heart failure
• cardiomyopathy
• mitral regurgitation

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MESH Headings

• Adult
• Aged
• Body Weight
• Catheterization, Swan-Ganz
• Central Venous Pressure
• Chronic Disease
• Edema/etiology
• Edema/physiopathology
• Edema/therapy
• Female
• Heart Failure/etiology
• Heart Failure/physiopathology
• Heart Failure/therapy
• Hemodynamics
• Hospitalization
• Humans
• Jugular Veins/physiopathology
• Male
• Middle Aged
• Mitral Valve Insufficiency/complications
• Mitral Valve Insufficiency/physiopathology
• Mitral Valve Insufficiency/therapy
• Patient Discharge
• Predictive Value of Tests
• Pulmonary Artery/physiopathology
• Pulmonary Wedge Pressure
• Stroke Volume
• Time Factors
• Treatment Outcome
• United States
• Ventricular Function, Left

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Grants

• N01HV98177 NHLBI NIH HHS
• R01 HL067691 NHLBI NIH HHS
• R01 HL067691-01 NHLBI NIH HHS
• N01-HV-98177 NHLBI NIH HHS

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Affiliation(s)

Maryse Palardy Brigham and Women's Hospital, Boston, Mass; Duke Medical Center, Durham, NC, USA
Lynne W Stevenson
Gudaye Tasissa
Michele A Hamilton
Robert C Bourge
Thomas G Disalvo
Uri Elkayam
James A Hill
Sharon C Reimold

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Plasma N-terminal protype-B natriuretic peptide levels in risk assessment of patients with mitral regurgitation secondary to ischemic and nonischemic dilated cardiomyopathy

BACKGROUND

Functional mitral regurgitation (MR) is a factor affecting prognosis of patients with chronic left ventricular (LV) dysfunction. The aim of the study was to investigate whether the evaluation of plasma N-terminal protype-B natriuretic peptide (NT-proBNP) concentrations is useful for prognostic assessment of patients with functional MR due to either ischemic or nonischemic chronic LV dysfunction.

METHODS

Echocardiograms were obtained in 207 patients with chronic LV dysfunction (ejection fraction <or=45%) and secondary MR at color flow imaging. The NT-proBNP was measured at the time of the index echocardiogram. The MR was graded as mild when a small central jet <4 cm(2) or <20% of left atrial area or a vena contracta width <0.3 cm was present. It was considered moderate in the presence of signs of more-than-mild MR without criteria for severe MR. A vena contracta width >or=0.7 cm raised MR grade to severe. Median follow-up duration was 29 months.

RESULTS

The NT-proBNP levels increased significantly with MR severity. At multivariate analysis, NT-proBNP was an independent predictor of cardiac death (hazard ratio 2.17, CI 1.10-4.30, P = .026) and the most powerful predictor of cardiac death or heart failure-related hospitalization (hazard ratio 3.19, CI 1.89-5.37, P < .0001). A progressively worse outcome was apparent when patients were stratified by a graded increase in MR severity and by quartiles of NT-proBNP levels. Increased NT-proBNP concentrations and more-than-mild MR identified patients with the highest risk of cardiac mortality.

CONCLUSION

Assessment of plasma NT-proBNP allows for stratifying patients with functional MR regardless of their degree of valvular incompetence. Even in case of only mild or moderate MR, but increased NT-proBNP, patients have to face poor outcome.

Role of vasodilators in regurgitant valve disease

Vasodilator therapy is designed to reduce regurgitant volume and improve left ventricular function. Acute administration reduces vascular resistance and decreases regurgitant volume and left ventricular filling pressure. These effects may be clinically useful in acute regurgitations, but less consistent results have been reported in long-term therapy. In chronic mitral functional regurgitation, vasodilator therapy has proved to have clinical or prognostic benefit only when heart failure or poor ventricular function is present. The indication of vasodilator treatment in aortic regurgitation has raised significant controversy. Several studies with small series have shown beneficial effects on regurgitant volume, ejection fraction, and mass of the left ventricle. Nevertheless, in the only two randomized long-term follow-up studies, results differed completely. In our experience, both nifedipine and enalapril failed to reduce the need for valvular surgery or show benefits in echocardiographic parameters. Vasodilator therapy would be indicated only in patients with severe aortic regurgitation and systemic hypertension, or when surgery is contraindicated.

Medical and surgical treatment of chronic mitral regurgitation

Chronic severe mitral regurgitation is a progressive disease that can lead to left ventricular dysfunction. New information on the natural history of the disease, along with advances in surgical techniques, has changed the roles of medical and surgical therapies. There is no well-defined role for medical therapy in chronic mitral regurgitation. The goal of the treating physician is therefore to identify the optimal timing for surgical intervention. The timing of surgical intervention depends primarily on two factors: (i) clinical symptoms and (ii) the left ventricular response to volume overload. However, the aetiology of mitral regurgitation, the likelihood of surgical repair, the occurrence of atrial fibrillation and the presence of pulmonary hypertension, together with the haemodynamic response to exercise, are important factors in the optimal surgical timing. New concepts in the understanding of the natural history of the disease coupled with success of mitral repair have recently resulted in a widespread evolution towards earlier surgery.

Functional Valvular Incompetence in Decompensated Heart Failure: Noninvasive Monitoring and Response to Medical Management

OBJECTIVE

We hypothesized that functional mitral and tricuspid valvular incompetence (MR and TR, respectively) are reversible causes of reduced cardiac output in decompensated heart failure (DF) that accompanies systolic dysfunction in ischemic or nonischemic cardiomyopathy.

BACKGROUND

DF, defined as signs and symptoms of heart failure at rest, is rooted in a salt-avid state transduced by neurohormonal activation secondary to impaired renal perfusion. Functional MR and TR are reversible causes of reduced systemic blood flow. Their impact on cardiac output, thoracic fluid content, cardiac chamber dimensions, and valvular apparatus function can be monitored noninvasively, before and after optimized medical management.

METHODS

Fourteen male subjects (66 +/- 8 years old) with reduced ejection fraction (24 +/- 5%) secondary to ischemic (71%) or nonischemic (29%) cardiomyopathy, who developed DF with clinical evidence of mitral (MR) and tricuspid (TR) valvular incompetence, were each assessed by bioimpedance and echocardiography before and 1 week after optimized medical management restored compensated failure.

RESULTS

Pharmacologic elimination of DF was accompanied by a reduction in body weight (P < 0.01). Hemodynamic improvements included a rise in cardiac index (2.1 to 2.6 L/min/m2; P < 0.01) and a reduction in predicted pulmonary artery systolic pressure (58 to 35 mm Hg; P < 0.001), thoracic fluid content (39 to 32 kOhm; P < 0.001), and systemic vascular resistance (1633 to 1209 dynes/sec/cm5; P < 0.001). Improvements in functional MR and TR included reductions in left and right atrial areas (27 to 24 cm and 26 to 23 cm2, respectively; P < 0.001), color-flow grading of MR and TR severity (P < 0.01), mitral regurgitant volume (105 to 65 mL; P < 0.001), and effective MR orifice size (0.8 to 0.6 cm2; P < 0.01).

CONCLUSIONS

In DF, functional MR and TR contribute to reduced cardiac output, increased thoracic fluid content, and systemic vascular resistance, together with enlarged atria and valvular orifice size, which can be improved by medical management. Bioimpedance and echocardiography provide for serial noninvasive assessments of hemodynamic status and valvular function in such cases.

Drug treatment of patients with decompensated heart failure

Decompensated heart failure (HF) may be defined as sustained deterioration of at least one New York Heart Association functional class, usually with evidence of sodium retention. Episodes of decompensation are most commonly precipitated by sodium retention, often associated with medication noncompliance. Our therapeutic approach to hospitalized patients is based on the documented hemodynamic responses to vasodilator therapy, with redistribution of mitral regurgitant flow to forward cardiac output and decompression of the left atrium. Invasive hemodynamic monitoring is seldom required for the effective management of patients with HF and there are risks associated with pulmonary artery catheterization. The currently available parenteral vasoactive drugs for decompensated heart failure include: (i) vasodilators such as nesiritide, nitroprusside and nitroglycerin (glyceryl trinitrate); (ii) catecholamine inotropes, primarily dobutamine; and (iii) inodilators such as milrinone, a phosphodiesterase inhibitor. Vasodilators are most appropriate for those patients who are primarily volume-overloaded, but with adequate peripheral perfusion. In this class of agents, nesiritide (recombinant human B-type natriuretic peptide) offers advantages over currently available drugs. Nesiritide produces rapid and sustained decreases in right atrial and pulmonary capillary wedge pressures, with reduction in pulmonary and systemic vascular resistance and increases in cardiac index. The hemodynamic effects of nesiritide infusion were sustained over a duration of 1 week and the drug may be used without intensive monitoring in patients with decompensated HF. Treatment with dobutamine is indicated in patients in whom low cardiac output rather than elevated pulmonary pressure is the primary hemodynamic aberration. However, milrinone reduces left atrial congestion more effectively than dobutamine, and is well tolerated and effective when used in patients receiving beta-blockers. In-patient therapy for decompensated HF is a short term exercise for symptom relief and provides an opportunity to re-assess management in the continuum of care.

Relationship between right and left-sided filling pressures in 1000 patients with advanced heart failure

BACKGROUND

Elevated left ventricular filling pressures present a major target of therapy for symptomatic heart failure but are difficult to assess directly. Because the relationship of left- and right-sided pressures remains ill defined in chronic heart failure, this study compared 3 right-sided measurements (right atrial [RA] pressure, pulmonary artery systolic [PAS] pressure, and severity of tricuspid regurgitation [TR]) to the pulmonary capillary wedge (PCW) pressure.

METHODS

Hemodynamic measurements and echocardiography were available from 1000 patients undergoing transplant evaluation. Right atrial and PAS pressure, and TR severity were compared to PCW pressure. For 754 patients undergoing repeat measurements, changes in RA and PAS pressures were compared to PCW changes.

RESULTS

Right atrial pressure correlated with PCW pressure (r = 0.64), regardless of etiology or TR severity. Right atrial pressure changes correlated with PCW changes (r = 0.62). Discordance was defined as either RA > or = 10 mm Hg despite PCW < 22 mm Hg (6%) or RA < 10 mm Hg despite PCW > or = 22 mm Hg (15%). For detection of PCW > or = 22 mm Hg, positive predictive values were 88% for RA > or = 10 mm Hg, 95% for PAS > or = 60 mm Hg, and 79% for > or = moderate TR. Pulmonary artery systolic pressure correlated very closely with PCW (r = 0.79), and could be estimated as 2 x PCW. Reduction in PAS pressure during therapy was strongly determined by PCW pressure reduction (r = 0.67).

CONCLUSIONS

Accurate estimation of RA pressure can potentially guide therapy of left ventricular filling pressures in approximately 80% of chronic heart failure patients without obvious non-cardiac disease. In this population, elevated PAS pressures are largely determined by elevated left-sided filling pressures.

Long-term hemodynamic responses to vasodilator therapy in patients with severe left ventricular dysfunction

Maximal oral vasodilator therapy resulted in long-term reduction of initially elevated pulmonary vascular resistance in 10 of 13 patients with severe heart failure who tolerated inotrope-supported uptitration of afterload reduction. Eleven patients were unable to tolerate vasodilator therapy and required inotropic support for successful cardiac transplantation.

Sustained hemodynamic effects of an infusion of nesiritide (human b-type natriuretic peptide) in heart failure: a randomized, double-blind, placebo-controlled clinical trial. Natrecor Study Group

OBJECTIVES

The goal of this study was to further define the role of nesiritide (human b-type natriuretic peptide) in the therapy of decompensated heart failure (HF) by assessing the hemodynamic effects of three doses (0.015, 0.03 and 0.06 microg/kg/min) administered by continuous intravenous (IV) infusion over 24 h as compared with placebo.

BACKGROUND

Previous studies have shown beneficial hemodynamic, neurohormonal and renal effects of bolus dose and 6-h infusion administration of nesiritide in HF patients. Longer term safety and efficacy have not been studied.

METHODS

This randomized, double-blind, placebo-controlled multicenter trial enrolled subjects with symptomatic HF and systolic dysfunction (left ventricular ejection fraction < or =35%). Central hemodynamics were assessed at baseline, during a 24-h IV infusion and for 4 h postinfusion.

RESULTS

One hundred three subjects with New York Heart Association class II (6%), III (61%) or IV (33%) HF were enrolled. Nesiritide produced significant reductions in pulmonary wedge pressure (27% to 39% decrease by 6 h), mean right atrial pressure and systemic vascular resistance, along with significant increases in cardiac index and stroke volume index, with no significant effect on heart rate. Beneficial effects were evident at 1 h and were sustained throughout the 24-h infusion.

CONCLUSIONS

The rapid and sustained beneficial hemodynamic effects of nesiritide observed in this study support its use as a first-line IV therapy for patients with symptomatic decompensated HF.

[Functional mitral regurgitation. Physiopathology and impact of medical therapy and surgical techniques for left ventricle reduction]

Functional mitral regurgitation is frequently observed in the setting of left ventricular dyfunction. This finding is a marker of poor outcome in patients with either ischemic or dilated cardiomyopathy. The mechanism accounting for this phenomenon is an altered balance of tethering versus coapting forces acting on the mitral valves in the failing heart. Tethering forces represent an anomalous tension on the mitral valves due to displacement of mitral valve attachments secondary to increased left ventricular chamber sphericity associated with systolic ventricular dysfunction. On the other hand, coapting forces are weak and unable to counteract the abnormal tension acting on the mitral valve, which restricts closure and leads to regurgitation. Vasodilators and inotropic drugs are effective in the management of functional mitral regurgitation. Although partial left ventriculectomy or Batista's procedure is still investigational, this new technique seems to provide an optimal control of functional mitral regurgitation and improve functional capacity and survival of some patients with heart failure.

Effects of high-dose lisinopril-isosorbide dinitrate on severe mitral regurgitation and heart failure remodeling

In long-term, 1-year follow-up, uptitration of angiotensin-converting enzyme inhibitor and nitrate therapy over established doses can further improve severe functional mitral regurgitation in patients with dilated cardiomyopathy due to a reversal of heart failure-related left ventricular remodeling. With marked left ventricular enlargement, >6.8 cm end-diastolic diameter, heart failure remodeling may be irreversible and resistant to further medical intervention.

Management of mitral regurgitation. Optimal timing for surgery

Chronic mitral regurgitation is a progressive disorder that can produce myocardial dysfunction in the absence of symptoms. Improvements in surgical techniques have resulted in earlier intervention, at times in asymptomatic patients. This article discusses the factors that influence prognosis, reviews the evidence supporting earlier intervention and provides guidelines for the management of patients with this lesion.

Effect of continuous positive airway pressure on mitral regurgitant fraction and atrial natriuretic peptide in patients with heart failure

OBJECTIVES

We sought to determine the effects of continuous positive airway pressure (CPAP) on mitral regurgitant fraction (MRF) and plasma atrial natriuretic peptide (ANP) concentration in patients with congestive heart failure (CHF).

BACKGROUND

In patients with CHF, elevated plasma ANP concentration is associated with elevated cardiac filling pressures. Secondary mitral regurgitation may contribute to elevation in plasma ANP concentration in patients with CHF. Because CPAP reduces transmural cardiac pressures and left ventricular (LV) volume, we hypothesized that long-term CPAP application would decrease the MRF and plasma ANP concentration in patients with CHF and Cheyne-Stokes respiration with central sleep apnea (CSR-CSA).

METHODS

Seventeen patients with CHF and CSR-CSA underwent baseline assessments of plasma ANP concentration and left ventricular ejection fraction (LVEF) and MRF by radionuclide angiography. They were then randomized to receive nocturnal CPAP plus optimal medical therapy (n = 9) or optimal medical therapy alone (n = 8) for 3 months and were then reassessed.

RESULTS

In the CPAP-treated group, LVEF increased from (mean +/-SEM) 20.2 +/- 4.2% to 28.2 +/- 5.3% (p < 0.02); MRF decreased from 32.8 +/- 7.7% to 19.4 +/- 5.5% (p < 0.02); and plasma ANP concentration decreased from 140.9 +/- 20.8 to 103.9 +/- 17.0 pg/ml (p < 0.05). The control group experienced no significant changes in LVEF, MRF or plasma ANP concentration. Among all patients, the change in plasma ANP concentration from baseline to 3 months correlated significantly with the change in MRF (r = 0.789, p < 0.0002).

CONCLUSIONS

In patients with CHF, CPAP-induced reductions in MRF and plasma ANP concentration in association with improvements in LVEF indicate improved cardiac mechanics. Our findings also suggest that reductions in plasma ANP concentration were at least partly due to reductions in MRF.

Sustained hemodynamic efficacy of therapy tailored to reduce filling pressures in survivors with advanced heart failure

BACKGROUND

During therapy to relieve congestion in advanced heart failure, cardiac filling pressures can frequently be reduced to near-normal levels with improved cardiac output. It is not known whether the early hemodynamic improvement and drug response can be maintained long term.

METHODS AND RESULTS

After referral for cardiac transplantation with initially severe hemodynamic decompensation, 25 patients survived without transplantation to undergo hemodynamic reassessment after 8+/-6 months of treatment tailored to early hemodynamic response. Initial changes included net diuresis, increased ACE inhibitor doses, and frequent addition of nitrates. After 8 months of therapy, early reductions were sustained for pulmonary wedge pressure (24+/-9 to 15+/-5 mm Hg early; 12+/-6 mm Hg late) and systemic vascular resistance (1651+/-369 to 1207+/-281 dynes x s(-1) x cm(-5) early; 1003+/-193 dynes x s(-1) x cm(-5) late). Acute response to doses persisted at reevaluation. Sustained reduction in filling pressures was accompanied by a progressive increase in stroke volume (42+/-10 to 56+/-13 mL early; 79+/-20 mL late), improved functional class, and freedom from resting symptoms. Study design did not control for amiodarone, which was initiated for arrhythmias in 12 patients and associated with greater improvement in cardiac index (1.8 to 3.2 L min(-1) x m(-2) late on amiodarone versus 2.0 to 2.6 L x min(-1) x m(-2), P<.05).

CONCLUSIONS

During chronic therapy tailored to early hemodynamic response in advanced heart failure, acute vasodilator response persists, and near-normal filling pressures can be maintained in patients who survive without transplantation. Stroke volumes at low filling pressures increase further over time. Chronic hemodynamic improvement was accompanied by symptomatic improvement, but the contributions of the monitored hemodynamic approach, increased vasodilator doses, and comprehensive outpatient management have not yet been established.

Insights into the mechanism of the nitroprusside-induced increase in cardiac output in failing hearts: an attempt at its prediction with Doppler echocardiography

Increased left ventricular (LV) diastolic pressure is consistently decreased by the administration of nitroprusside; however, nitroprusside-induced changes in cardiac output (CO) vary among patients with failing hearts. Although the variation has been considered to be related to interindividual inhomogeneity of LV diastolic performance, nitroprusside-induced changes in CO are not predictable before drug administration in individual subjects. We attempted to clarify whether nitroprusside-induced changes in CO may be predicted by analysis of the mitral flow velocity pattern in failing hearts. LV diastolic pressure was increased by the combination of the decrease in LV function and the volume expansion, and 15 conditions with LV end-diastolic pressure (EDP) > or =15 mm Hg were obtained in 8 dogs. In each condition, pulsed Doppler mitral flow velocity patterns were recorded simultaneously with hemodynamic variables before and during intravenous nitroprusside infusion. After nitroprusside administration, LV systolic pressure and LVEDP decreased in all dogs, and CO increased in eight conditions but decreased in seven conditions. CO was more likely to increase with administration of nitroprusside, and its change was greater in the conditions in which deceleration time of the early diastolic filling wave before nitroprusside infusion was longer (r = 0.56, p<0.05, n = 15). Better correlation was obtained with multiple-regression analysis, using the deceleration time and peak filling velocity at atrial contraction (r = 0.67, p<0.05, n = 15). The deceleration time correlated with LV dynamic compliance (r = 0.66, p<0.01, n = 30). Analysis of mitral flow velocity patterns may be useful in predicting nitroprusside-induced changes in CO in failing hearts.

Vasoactive drugs in chronic regurgitant lesions of the mitral and aortic valves

This review examines the results of vasodilator therapy in patients with chronic regurgitant lesions of the aortic and mitral valves. The analysis includes those studies which provide data on hemodynamic measurements, left ventricular systolic function, ventricular volumes and regurgitant flow. In patients with chronic aortic or mitral regurgitation, the short-term administration of nitroprusside, hydralazine, nifedipine or an angiotensin-converting enzyme (ACE) inhibitor produces salutary hemodynamic effects. The major difference in the response to combined preload and afterload reduction (i.e., nitroprusside) in patients with aortic versus mitral regurgitation was that forward stroke volume generally increased and ejection fraction remained unchanged in mitral regurgitation, whereas ejection fraction generally increased and forward stroke volume remained unchanged in aortic regurgitation. These observations suggest that a reciprocal relation between regurgitant and forward flow characterizes the response to preload and afterload reduction in mitral regurgitation (through a preload-dependent dynamic regurgitant orifice), whereas correction of afterload mismatch dominates the response in aortic regurgitation. In studies of long-term vasodilator therapy in patients with chronic aortic regurgitation, a reduction in left ventricular volumes and regurgitant fraction, with or without an increase in ejection fraction, has been observed during treatment with hydralazine, nifedipine and ACE inhibitors. Patients with the largest, sickest hearts generally benefit the most from treatment with vasoactive drugs. Nonetheless, favorable ventricular remodeling has been reported in asymptomatic patients, and long-term nifedipine use has delayed the need for operation in asymptomatic patients with chronic aortic regurgitation. For patients with chronic mitral regurgitation, definition of the etiology of the lesion is a prerequisite for choosing appropriate therapy. Excluding patients with obstructive hypertrophic cardiomyopathy and mitral valve prolapse, and some with fixed-orifice (i.e., rheumatic) mitral regurgitation, the signal importance of preload reduction suggests that the preferred long-term therapy for symptomatic chronic mitral regurgitation is an ACE inhibitor. There are no long-term studies that support the use of vasodilator therapy in asymptomatic patients with chronic mitral regurgitation.

Basal release of endothelium-derived nitric oxide plays an important role in the prevention of afterload mismatch in acute left ventricular dysfunction

The basal release of endothelium-derived nitric oxide (EDNO) is considered to play an important role in regulating the vascular tone in normal subjects; however, its role in the presence of acute heart failure is unknown. This study was designed to clarify the role of a basal release of EDNO in the presence of acute heart failure. Acute ischemic left ventricular (LV) dysfunction was produced in 22 dogs by coronary microembolization. After the embolization, only saline solution was intravenously infused for sixty minutes in 10 dogs. In another 12 dogs, NG-monomethyl-L-arginine (L-NMMA), which is known to inhibit the formation of EDNO in the vascular endothelium, was intravenously infused at a rate of 20 micrograms/kg/minute for sixty minutes. Infusion of saline solution did not produce any changes in hemodynamic variables. Infusion of L-NMMA caused increases in mean aortic pressure, systemic vascular resistance, and LV end-diastolic pressure without changes in the LV peak + and - dP/dt (time constant) of LV pressure fall, and these changes were associated with a giant "v" wave in the tracing of left atrial pressure and a decrease in cardiac output. The basal release of EDNO may play an important role in the prevention of afterload elevation, subsequent cardiac output reduction, and afterload mismatch in the presence of acute heart failure.

Effect of captopril on functional mitral regurgitation in dilated heart failure: a randomised double blind placebo controlled trial

OBJECTIVE

To determine the efficacy and dose requirements of captopril to reduce functional mitral regurgitation in patients with dilated heart failure.

DESIGN

A randomised double blind placebo controlled parallel arm trial. Incremental daily doses of 25 mg, 50 mg and 100 mg captopril used for a four week period each for a total of 12 weeks preceded by a two week placebo washout. Twenty eight ambulatory patients (mean age 72) New York Heart Association (NYHA) class II or III with apparently controlled ischaemic dilated heart failure (ejection fraction 29% (0.04%)) on digoxin, diuretics, and nitrates were randomised. All had at least grade 2/4 functional mitral regurgitation (> 5 cm2 regurgitant area on colour flow Doppler).

RESULTS

Twenty three patients completed the study (13 on placebo and 10 on captopril). Significant improvements were confined to the captopril group. Compared with placebo the following improvements were noted in the captopril treated group: mitral regurgitant area decreased from a threshold at 50 mg/day (p < 0.05, mean (95% confidence interval (95% CI)) 3.1 (0.2 to 6.0) cm2), with a further decrease at 100 mg/day (p < 0.01, mean (95% CI) 5.3 (3.1 to 7.5) cm2). Significant improvements in all the other measurements were noted only after 100 mg/day. Stroke volume increased (p < 0.01, mean (95% CI) 11, (1.4 to 21) ml), systemic vascular resistance decreased (p < 0.05, mean (95% CI) 414 (35 to 793) dyn s cm5), left atrial area decreased (p < 0.05, mean (95% CI) 4.3 (0.03 to 8.6) cm2), and deceleration time increased (p < 0.01, mean (95% CI) 52 ms (7 to 98) ms). Left ventricular diameter decreased marginally (p = 0.06, mean (95% CI) 4 (-0.05 to 9 mm). Duke activity index score increased (p < 0.001, median (95% CI) 6.8 (4.5 to 12) points). Heart rate, mean arterial blood pressure, serum creatinine, and serum potassium did not change with either placebo or captopril. No patient was withdrawn directly due to the side effects of captopril. In an open phase nine placebo patients given captopril in rapid increments reaching 100 mg/day in the fourth week showed similar improvements.

CONCLUSION

Captopril is efficacious in reducing functional mitral regurgitation in dilated heart failure. Patients require and must tolerate high doses (50-100 mg/day) for additive effects over supervised conventional treatment to occur.

Doppler echocardiographic assessment of left ventricular filling in idiopathic dilated cardiomyopathy during a one-year follow-up: relation to the clinical course of disease

In idiopathic dilated cardiomyopathy (IDC), an impaired left ventricular filling as assessed by the Doppler echocardiographic mitral flow pattern is closely related to the severity of congestive heart failure. This study examined the relation of left ventricular filling and the clinical course of the disease in patients with a recent diagnostic procedure and initiation of medical therapy (group 1, n = 15) as compared with patients in a chronic stage of the disease (group 2, n = 24) with the diagnosis established > 1 year before. All patients had to be in sinus rhythm to facilitate the Doppler echocardiographic evaluation of left ventricular filling. The clinical status was assessed by the New York Heart Association classification and a heart failure score at baseline and after a period of 12 +/- 7 months. At baseline the ratio of the peak early/atrial Doppler velocities (VE/VA) was shifted toward the early diastole in group 1 as compared to group 2 (1.84 +/- 1.02 vs 1.12 +/- 0.55; p < 0.05). Symptoms of heart failure were more severe in group 1. During follow-up, VE/VA tended to decrease in group 1 from 1.84 +/- 1.02 to 1.35 +/- 1.03 (p = 0.07) and remained unchanged in group 2 (1.12 +/- 0.55 and 1.34 +/- 1.23; not significant). In a subgroup of 10 patients who underwent repeat right heart catheterization, the decrease of VE/VA coincided with a decrease of the pulmonary capillary wedge pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute effects of dobutamine on myocardial oxygen consumption and cardiac efficiency measured using carbon-11 acetate kinetics in patients with dilated cardiomyopathy

OBJECTIVES

The aim of this study was to use positron emission tomography (PET)-derived carbon (C)-11 acetate kinetics to determine the effects of dobutamine on oxidative metabolism and its effects on myocardial efficiency in a group of patients with dilated cardiomyopathy.

BACKGROUND

Dobutamine is known to improve myocardial function but may do so at the expense of myocardial oxygen consumption, which could be a potential deleterious effect. Carbon-11 acetate kinetics correlate with myocardial oxygen consumption as shown in animal models. Combining these scintigraphic measurements of oxygen consumption with estimates of cardiac work results in a work-metabolic index, which reflects cardiac efficiency.

METHODS

Eight patients with nonischemic dilated cardiomyopathy underwent dynamic PET imaging, echocardiography and hemodynamic measurements. Seven of these patients were also studied while receiving dobutamine. Direct measurements of myocardial oxygen consumption using coronary sinus catheterization were obtained with eight of the PET studies to validate C-11 acetate in patients with cardiomyopathy.

RESULTS

The mean (+/- SD) C-11 clearance rate significantly increased with dobutamine from 0.105 +/- 0.027 to 0.155 +/- 0.023 min-1 (p = 0.001). Directly measured myocardial oxygen consumption had a linear relation to the mean C-11 clearance rate (r = 0.8, p = 0.018). Dobutamine was noted to significantly reduce systemic vascular resistance as well as the severity of mitral regurgitation. The work-metabolic index determined using hemodynamic variables and PET data increased from 2 +/- 0.7 x 10(4) to 2.6 +/- 0.6 x 10(4) (p = 0.04). Efficiency, estimated by employing the oxygen consumption to k2 relation, also increased from 13 +/- 4.5% to 16.9 +/- 6.4% (p = 0.04).

CONCLUSIONS

Despite an increase in myocardial oxygen consumption, dobutamine led to an increase in work-metabolic index in patients with dilated nonischemic cardiomyopathy. Dobutamine reduced systemic vascular resistance and mitral regurgitation, suggesting that in this group of patients, it had important vasodilatory action in addition to its inotropic effects. The use of the C-11 acetate PET for determining myocardial oxygen consumption and estimating efficiency could potentially complement existing clinical measures of ventricular performance and may allow improved and objective evaluation of therapy in patients with heart failure.

Hemodynamic response to intravenous enalaprilat in patients with severe congestive heart failure and mitral regurgitation

The hemodynamic response 1 hour after 1.25 mg of intravenous (IV) enalaprilat was examined in 20 patients (mean age 75 years) with severe congestive heart failure (CHF) and mitral regurgitation (MR), secondary to ischemic heart disease (NYHA Class IV). Patients were classified into two groups based upon the magnitude of MR as derived from Doppler color flow imaging: Group I (n = 13) had severe MR and Group II (n = 7) had moderate MR. Acute therapy significantly reduced systemic vascular resistance index in both groups and provided effective afterload reduction. Although cardiac and stroke volume indices increased in both groups, an improved forward flow was significant only for Group I (cardiac index 2.2 +/- 0.5 to 2.7 +/- 0.5 l/min/m2, p < 0.02). The magnitude of MR, acutely reduced in all patients, was similarly significant only for Group I (56 +/- 10% to 31 +/- 12%, p < 0.01). The reduction of both pulmonary capillary wedge pressure and mean arterial pressure was significant for both groups. This study supports the use of IV enalaprilat, a parenteral angiotensin-converting enzyme (ACE) inhibitor, as an effective and rapidly acting vasodilator in the management of selected patients with chronic heart failure and MR who require immediate hemodynamic improvement.

Effectiveness of preload reserve as a determinant of clinical status in patients with left ventricular systolic dysfunction. The SOLVD Investigators

The hemodynamic determinants of clinical status in patients with left ventricular (LV) systolic dysfunction have not been established. In the present study, preload reserve--LV distension during exercise--was related to clinical status, and the effect of acute angiotensin-converting enzyme inhibition was examined in 97 patients with ejection fraction less than or equal to 0.35 enrolled in the trial, Studies of Left Ventricular Dysfunction (SOLVD). Sixty-one asymptomatic patients (group I) were compared with 36 patients with symptomatic heart failure (group II). Radionuclide LV volumes were measured at rest and during maximal cycle exercise. Group II patients had higher resting heart rates, end-diastolic and end-systolic volumes, and lower ejection fractions (all p less than 0.005). During exercise, only patients in group I had increased stroke volume (from 35 +/- 8 to 39 +/- 11 ml/m2 [mean +/- SD; p less than 0.0005]) due to an increase in end-diastolic volume (from 119 +/- 29 to 126 +/- 29 ml/m2 [p less than 0.0005]), contributing to a greater increase in LV minute output (p less than 0.0001, group I vs group II). After administration of intravenous enalapril (1.25 mg), LV end-diastolic volume response to exercise was augmented in group II (rest, 140 +/- 42; exercise, 148 +/- 43 ml/m2; p less than 0.0005) and LV output response increased slightly (p less than 0.05). Thus, in patients with asymptomatic systolic dysfunction, recruitment of preload during exercise is responsible for maintaining a stroke volume contribution to the cardiac output response.(ABSTRACT TRUNCATED AT 250 WORDS)

Management of refractory congestive heart failure

Despite recent advances in the treatment of congestive heart failure (CHF), many patients continue to present with symptoms refractory to digoxin, diuretic, and vasodilatory therapy. Since it is unlikely that this population will decrease in the near future, practical approaches to management of refractory CHF are reviewed. Refractory CHF here is defined as New York Heart Association (NYHA) functional class III-IV heart failure, despite maximal drug therapy. Before such a diagnosis is made, the patient should be treated with digoxin, diuretics, and a vasodilator. Approach to therapy requires assessment of changing clinical status and pathophysiology, optimizing oral drug treatment, and providing temporary parenteral support when indicated. Specific attention should be given to factors that influence the optimal response to each of these 3 treatment classes. A theoretical, but unproven, concept suggests that combined vasodilatory therapy may be appropriate as long as excessive hypotension is avoided. In the course of management, a decision is required as to whether further optimization of therapy can be achieved on an outpatient basis. Hospital-based intravenous inotropic support given for 2-4 days will often provide the opportunity to restructure patient therapy.

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.

Does the magnitude of mitral regurgitation determine hemodynamic response to vasodilation in chronic congestive heart failure?

Although it is usually assumed that direct-acting vasodilators improve cardiac function in patients with congestive heart failure (CHF) by altering left ventricular preload and afterload, several studies have suggested that most of the benefit occurs as a result of a reduction in associated mitral regurgitation (MR), which is present in the majority of patients with severe CHF. To test his hypothesis, the hemodynamic response to oral hydralazine was examined in CHF patients with competent mitral prostheses (group 1) and patients with CHF due to severe MR and left ventricular dysfunction (group 2). Both groups demonstrated significant increases in cardiac, stroke volume, and stroke work indices, although these were greater in group 2. Only group 2 experienced a significant reduction in left ventricular filling pressure. Thus, the presence of MR is not essential for hemodynamic improvement but is associated with significantly greater responses.

Afterload reduction with vasodilators and diuretics decreases mitral regurgitation during upright exercise in advanced heart failure

In advanced heart failure, mitral regurgitation increases the burden of the failing ventricle and decreases effective stroke volume. Although tailored afterload reduction decreases mitral regurgitation at rest, it is not known if this benefit is maintained during upright exercise. Simultaneous radionuclide ventriculography and thermodilution stroke volumes were compared to measure the forward ejection fraction in 10 patients during upright bicycle exercise before and after therapy with vasodilators and diuretics tailored to decrease pulmonary capillary wedge pressure and systemic vascular resistance. Ventricular volumes, total ejection fraction and the forward ejection fraction did not change during exercise at baseline. At rest, tailored therapy decreased average pulmonary capillary wedge pressure from 36 to 19 mm Hg (p less than 0.01), systemic vascular resistance from 1,570 to 1,210 dynes.s.cm-5 (p less than 0.05), and left ventricular volume index from 251 to 177 ml/m2 (p less than 0.01), while increasing the forward ejection fraction from 0.53 to 0.85 (p less than 0.01) without change in total ejection fraction (0.18 from 0.17). During steady state exercise at low work load, tailored therapy decreased left ventricular volume index from 279 to 213 (p less than 0.05) and increased forward ejection fraction from 0.52 to 0.79 (p less than 0.01) without change in total ejection fraction (0.20 from 0.19). The total stroke volume during exercise was not increased after therapy; the increase in forward stroke volume after therapy appeared to result instead from the decrease in mitral regurgitant flow. The benefits of tailored afterload reduction are maintained throughout upright exercise.

Dynamics of functional mitral regurgitation during dobutamine therapy in patients with severe congestive heart failure: a Doppler echocardiographic study

Functional mitral regurgitation plays a major role in determining the therapeutic response to vasodilators in patients with severe congestive heart failure. Its role in the response to inotropic therapy has not been studied in these patients. Ten patients with stage 3 or 4 congestive heart failure (New York Heart Association class) and secondary mitral regurgitation were studied before and during intravenous administration of dobutamine (mean dose, 7.4 microgram/kg/min). Hemodynamic measurements were obtained invasively. Echo and Doppler cardiography were used to determine cardiac volumes. Mitral regurgitation was calculated as the difference between total stroke volume by echo and forward stroke volume by Doppler. Mitral regurgitation area was calculated from a modified hemodynamic formula. Dobutamine caused a marked rise in mean forward stroke volume (43 to 61 ml), with a decrease in mitral regurgitation volume from 20 to 10 ml/beat and a drop in pulmonary capillary wedge pressure from 21 to 13 mm Hg. Since the pressure gradient between the left ventricle and atrium increased significantly during dobutamine therapy, only a marked decrease in the orifice of regurgitation could explain the changes in regurgitant volume. Indeed, the end-diastolic volume decreased from 254 to 234 ml and the orifice of mitral regurgitation was reduced from 0.25 to 0.12 cm2.

Dynamic mitral regurgitation. An important determinant of the hemodynamic response to load alterations and inotropic therapy in severe heart failure

Cardiac performance and mitral regurgitation were measured by Doppler echocardiography and right heart catheterization in 12 patients with severe congestive heart failure who performed isometric exercise during control and intravenous administration of dobutamine and nitroglycerin. During control isometric exercise, mitral regurgitant volume increased from 18 +/- 13 to 31 +/- 17 ml (p less than 0.01), while forward stroke volume, by both thermodilution and Doppler echocardiography, substantially decreased. At rest, dobutamine decreased mitral regurgitant volume from 18 +/- 13 to 11 +/- 10 ml (p less than 0.05), while forward stroke volume increased from 46 +/- 13 to 55 +/- 15 ml (p less than 0.05). During isometric exercise, dobutamine tended to decrease mitral regurgitant volume (24 +/- 12 vs. 31 +/- 17 ml; NS) when compared with control exercise. At rest, nitroglycerin decreased mitral regurgitant volume from 18 +/- 13 to 11 +/- 11 ml (p less than 0.05), while forward stroke volume, by both thermodilution and Doppler echocardiography, substantially increased. Similarly, during isometric exercise, nitroglycerin decreased mitral regurgitant volume from 31 +/- 17 to 20 +/- 14 ml (p less than 0.05), while significantly increasing forward stroke volume. At control rest, the median mitral regurgitant fraction was 24% for the 12 patients. Neither dobutamine nor nitroglycerin changed significantly forward stroke and mitral regurgitant volumes at rest and during isometric exercise in the six patients with resting mitral regurgitant fraction below the median. In contrast, dobutamine and nitroglycerin significantly decreased mitral regurgitant volume and increased forward stroke volume both at rest and during isometric exercise in the six patients with mitral regurgitant fraction greater than the median.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of medical therapy tailored for severe congestive heart failure in patients transferred for urgent cardiac transplantation

Cardiac transplantation can only be performed in a few patients with severe congestive heart failure (CHF), due to the shortage of donor hearts. The efficacy of current medical therapy tailored for severe CHF, which has not previously been determined for transplant candidates, is of particular importance in patients considered for urgent cardiac transplantation. In this study, 50 consecutive in-patients transferred from other hospitals for urgent transplantation underwent intensive afterload reduction therapy, initially with intravenous and subsequently with oral vasodilators and diuretics tailored to hemodynamic goals. Oral regimens allowed hospital discharge without surgery for 40 of 50 patients. Nineteen of these patients had arrived on inotropic infusions and 32 had received oral vasodilators in the previous month. Cardiac index increased from 1.9 +/- 0.6 to 2.8 +/- 0.7 liters/min/m2, while pulmonary capillary wedge pressure decreased from 30 +/- 8 to 15 +/- 4 mm Hg and systemic vascular resistance decreased from 1,800 +/- 800 to 1,100 +/- 200 dynes-s-cm-5. Despite poor initial hemodynamics, ejection fraction 16 +/- 4%, serum sodium 131 +/- 6 mEq/liter, and apparent failure of previous medical therapy, actuarial survival for 24 discharged patients receiving sustained medical therapy alone was 67% at 1 year, with 67% of survivors employed full- or part-time, and 14 of 16 (88%) discharged transplant candidates survived until transplantation. By decreasing the need for transplantation to be performed urgently, increased emphasis on the design of medical therapy may allow more effective distribution of limited donor hearts.

Noninvasive quantification of mitral regurgitation in dilated cardiomyopathy: correlation of two Doppler echocardiographic methods

The presence and severity of functional mitral regurgitation were quantified by Doppler echocardiography in 17 patients with dilated cardiomyopathy and no evidence of primary valvular disease. Mitral regurgitant fraction was greater than 20% in 11 of the 17 patients, and exceeded 40% in four patients. Total stroke volume, calculated from the difference between end-diastolic and end-systolic volumes obtained by two-dimensional echocardiography, correlated well with mitral valve inflow determined by Doppler echocardiography (r = 0.90, p less than 0.001). Similarly, mitral regurgitant volume, calculated as the difference between echocardiographic total stroke volume and forward aortic volume obtained by Doppler echocardiography, correlated well with regurgitant volume calculated as the difference between mitral valve inflow and forward aortic flow, both determined by Doppler echocardiography (r = 0.90, p less than 0.001). Accordingly, functional mitral regurgitation can be conveniently demonstrated in patients with dilated cardiomyopathy by two different Doppler echocardiography methods, whose results are closely correlated. Mitral regurgitant fraction is greater than 20% in two thirds of the patients with a dilated cardiomyopathy.

Effects of afterload reduction (diuretics and vasodilators) on left ventricular volume and mitral regurgitation in severe congestive heart failure secondary to ischemic or idiopathic dilated cardiomyopathy

The mechanism by which afterload reduction increases left ventricular stroke volume while decreasing left ventricular filling pressure has not previously been established. In 15 patients with severe congestive heart failure due to ischemic or idiopathic dilated cardiomyopathy, absolute ventricular volume, ejection fraction and total stroke volume from radionuclide ventriculography were compared with thermodilution stroke volume before and after intensive afterload reduction with vasodilators and diuretics titrated to hemodynamic goals. After 48 to 72 hours, pulmonary artery wedge pressure decreased from 32 +/- 8 to 16 +/- 4 mm Hg and systemic vascular resistance from 1,960 +/- 700 to 1,200 +/- 400 dynes s cm-5. End-diastolic volume decreased from 390 +/- 138 to 301 +/- 126 ml (p less than 0.01) and end-systolic volume from 316 +/- 127 to 241 +/- 111 (p less than 0.01). Ejection fraction did not change and total stroke volume decreased from 74 +/- 22 to 59 +/- 20 ml (p less than 0.01). Simultaneous forward stroke volume by thermodilution increased from 37 +/- 14 to 52 +/- 14 ml (p less than 0.01), and forward fraction increased from 0.55 +/- 0.40 to 0.96 +/- 0.42. Intensive reduction of ventricular filling pressure and systemic vascular resistance decreased total ventricular stroke volume by 20% but increased forward stroke volume by 40%. The major effect of intensive afterload reduction for severe congestive heart failure may be the reduction of ventricular volume and mitral regurgitation.

Comparative effects on hemodynamics of enoximone (MDL 17,043), dobutamine and nitroprusside in severe congestive heart failure

To assess their comparative effects on hemodynamics, nitroprusside, dobutamine and enoximone were sequentially administered to 10 patients with severe congestive heart failure. Nitroprusside, dobutamine (at 10 micrograms/kg/min) and enoximone (at 2 mg/kg) increased stroke volume index to a similar extent (31%, 34% and 36%, respectively). Enoximone produced less tachycardia than dobutamine and, consequently, a smaller improvement in cardiac index. Mean arterial pressure was not altered by dobutamine but was reduced 9% by enoximone, 2 mg/kg. This finding accounts for the larger (although not significant) increase in left ventricular stroke work index observed with dobutamine compared with enoximone. Ventricular filling pressures and vascular resistances were significantly decreased by all 3 drugs (p = 0.001). All 3 drugs improved cardiac pump function when assessed by the increase in stroke index to a similar extent; however, enoximone (2 mg/kg) resulted in less hypotension than nitroprusside (mean arterial pressure -9% vs -22%, p = 0.0001) and in less tachycardia than dobutamine 10 micrograms/kg/min. Those differences in mode of action account for the variations observed in the heart rate-blood pressure product (dobutamine 10 micrograms/kg/min, +18%, enoximone 2 mg/kg, -5%, p = 0.003). Enoximone thus appears to be of great value in the management of severe congestive heart failure by its combination of vasodilatory and inotropic properties. Enoximone (2 mg/kg) provides a clinically significant increase in cardiac index, a clear reduction of ventricular filling pressures, a moderate reduction of mean arterial pressure and only minor changes of heart rate and of rate pressure product.

Hemodynamic correlates of left ventricular versus right ventricular radionuclide volumetric responses to vasodilator therapy in congestive heart failure secondary to ischemic or dilated cardiomyopathy

Previous studies have failed to demonstrate the clinical relevance of radionuclide functional measurements during treatment of congestive heart failure (CHF). In the present study, data derived before and during nitroprusside infusion were analyzed in 16 patients with CHF to compare correlations of changes in left (LV) and right ventricular (RV) radionuclide measurements with simultaneous changes in 8 hemodynamic variables. Nitroprusside infusion decreased systemic artery pressure, pulmonary arterial wedge pressure, pulmonary artery pressure, right atrial pressure, and pulmonary and systemic vascular resistance, and increased cardiac output. Nitroprusside decreased LV and RV end-diastolic and end-systolic volumes and increased LV and RV ejection fraction and stroke volume. Changes in RV volumes exceeded changes in LV volumes. LV radionuclide measurements did not correlate significantly with any hemodynamic measurement except for a weak correlation between changes in LV end-systolic volume and right atrial pressure (r = 0.51). In contrast, the combination of changes in RV end-systolic volume and stroke volume predicted changes in pulmonary artery peak systolic (r = 0.90) and mean (r = 0.89) pressures. Changes in pulmonary arterial wedge pressure correlated with changes in RV end-diastolic (r = 0.78) and end-systolic (r = 0.71) volumes. In conclusion, LV radionuclide measurements are of limited value in predicting hemodynamic responses to vasodilator therapy in CHF, whereas RV volumes are strongly influenced by load changes. Their responses to nitroprusside correlate well with changes in pulmonary artery and pulmonary arterial wedge pressures.