Acute hemodynamic effects of conivaptan, a dual V(1A) and V(2) vasopressin receptor antagonist, in patients with advanced heart failure

BACKGROUND

Arginine vasopressin may contribute to abnormalities in hemodynamics and fluid balance in heart failure through its actions on V(1A) (vascular and myocardial effects) and V(2) receptors (renal effects). Inhibiting the action of vasopressin may be beneficial in patients with heart failure.

METHODS AND RESULTS

A total of 142 patients with symptomatic heart failure (New York Heart Association class III and IV) were randomized to double-blind, short-term treatment with conivaptan, a dual V(1a)/V(2) vasopressin receptor antagonist, at a single intravenous dose (10, 20, or 40 mg) or placebo. Compared with placebo, conivaptan at 20 and 40 mg significantly reduced pulmonary capillary wedge pressure (-2.6+/-0.7, -5.4+/-0.7, and -4.6+/-0.7 mm Hg for placebo and 20 and 40 mg groups, respectively; P<0.05) and right atrial pressure (-2.0+/-0.4, -3.7+/-0.4, and -3.5+/-0.4 mm Hg for placebo and 20 and 40 mg groups, respectively; P<0.05) during the 3- to 6-hour interval after intravenous administration. Conivaptan significantly increased urine output in a dose-dependent manner (-11+/-17, 68+/-17, 152+/-19, and 176+/-18 mL/hour for placebo and 10, 20, and 40 mg groups, respectively; P<0.001) during the first 4 hours after the dose. Changes in cardiac index, systemic and pulmonary vascular resistance, blood pressure, and heart rate did not significantly differ from placebo.

CONCLUSIONS

In patients with advanced heart failure, vasopressin receptor antagonism with conivaptan resulted in favorable changes in hemodynamics and urine output without affecting blood pressure or heart rate. These data suggest that vasopressin is functionally significant in advanced heart failure and that further investigations are warranted to examine the effects of conivaptan on symptom relief and natural history in such patients.

Cardiovascular thrombotic events in controlled, clinical trials of rofecoxib

BACKGROUND

In comparing aspirin, nonselective nonsteroidal antiinflammatory agents (NSAIDs), and cyclooxygenase (COX)-2 inhibitors, variation in platelet inhibitory effects exists that may be associated with differential risks of cardiovascular (CV) thrombotic events. Among the randomized, controlled trials with the COX-2 inhibitor rofecoxib, one study demonstrated a significant difference between rofecoxib and its NSAID comparator (naproxen) in the risk of CV thrombotic events. A combined analysis of individual patient data was undertaken to determine whether there was an excess of CV thrombotic events in patients treated with rofecoxib compared with those treated with placebo or nonselective NSAIDs.

METHODS AND RESULTS

CV thrombotic events were assessed across 23 phase IIb to V rofecoxib studies. Comparisons were made between patients taking rofecoxib and those taking either placebo, naproxen (an NSAID with near-complete inhibition of platelet function throughout its dosing interval), or another nonselective NSAIDs used in the development program (diclofenac, ibuprofen, and nabumetone). The major outcome measure was the combined end point used by the Antiplatelet Trialists' Collaboration, which includes CV, hemorrhagic, and unknown deaths; nonfatal myocardial infarctions; and nonfatal strokes. More than 28 000 patients, representing >14 000 patient-years at risk, were analyzed. The relative risk for an end point was 0.84 (95% CI: 0.51, 1.38) when comparing rofecoxib with placebo; 0.79 (95% CI: 0.40, 1.55) when comparing rofecoxib with non-naproxen NSAIDs; and 1.69 (95% CI: 1.07, 2.69) when comparing rofecoxib with naproxen.

CONCLUSIONS

This analysis provides no evidence for an excess of CV events for rofecoxib relative to either placebo or the non-naproxen NSAIDs that were studied. Differences observed between rofecoxib and naproxen are likely the result of the antiplatelet effects of the latter agent.

Reduced kidney function and anemia as risk factors for mortality in patients with left ventricular dysfunction

OBJECTIVES

We sought to evaluate the relationship between the level of kidney function, level of hematocrit and their interaction on all-cause mortality in patients with left ventricular (LV) dysfunction.

BACKGROUND

Anemia and reduced kidney function occur frequently in patients with heart failure. The level of hematocrit and its relationship with renal function have not been evaluated as risk factors for mortality in patients with LV dysfunction.

METHODS

We retrospectively examined the Studies Of LV Dysfunction (SOLVD) database. Glomerular filtration rate (GFR) was predicted using a recently validated formula. Kaplan-Meier survival analyses were used to compare survival times between groups stratified by level of kidney function (predicted GFR) and hematocrit. Cox proportional-hazards regression was used to explore the relationship of survival time to level of kidney function, hematocrit and their interaction.

RESULTS

Lower GFR and hematocrit were associated with a higher prevalence of traditional cardiovascular risk factors. In univariate analysis, reduced kidney function and lower hematocrit, in men and in women, were risk factors for all-cause mortality (p < 0.001 for both). After adjustment for other factors significant in univariate analysis, a 10 ml/min/1.73 m(2) lower GFR and a 1% lower hematocrit were associated with a 1.064 (95% CI: 1.033, 1.096) and 1.027 (95% CI: 1.015, 1.038) higher risk for mortality, respectively. At lower GFR and lower hematocrit, the risk was higher (p = 0.022 for the interaction) than that predicted by both factors independently.

CONCLUSIONS

Decreased kidney function and anemia are risk factors for all-cause mortality in patients with LV dysfunction, especially when both are present. These relationships need to be confirmed in additional studies.

Comparative effects of carvedilol and metoprolol on left ventricular ejection fraction in heart failure: results of a meta-analysis

BACKGROUND

Both metoprolol and carvedilol improve cardiac function and prolong survival in patients with heart failure. Carvedilol has broader antiadrenergic effects than metoprolol, but it is not clear whether this characteristic is associated with greater benefits on cardiac function during long-term treatment.

STUDY DESIGN

We performed a meta-analysis of all 19 randomized controlled trials of carvedilol or metoprolol that measured left ventricular ejection fraction before and after an average of 8.3 +/- 0.1 months of treatment in 2184 patients with chronic heart failure. The mean daily doses were 58 +/- 1 mg of carvedilol and the equivalent of 162 +/- 1 mg of extended-release metoprolol. In the 15 placebo-controlled trials, the mean ejection fraction increased more in the trials of carvedilol than in the trials of metoprolol (placebo-corrected increases of +0.065 and +0.038, respectively), P = .0002. In the 4 active-controlled trials that compared metoprolol directly with carvedilol, the mean ejection fraction also increased more in the carvedilol groups than in the metoprolol groups (+0.084 on carvedilol and +0.057 on metoprolol, respectively), P = .009. The difference in favor of carvedilol in the active-controlled trials was nearly identical to the difference observed in the placebo-controlled trials and was apparent in patients with and without coronary artery disease.

CONCLUSION

Long-term treatment with carvedilol produces greater effects on left ventricular ejection fraction than metoprolol when both drugs are prescribed in doses similar to those that have been shown to prolong life.

Economic impact of beta blockade in heart failure

We reviewed the literature on clinical trials of beta-adrenergic blockade for treatment of heart failure, seeking evidence of reductions in hospital admissions. To analyze the economic implications of six clinical trials, we developed a stochastic cost model to generate estimates of total medical costs resulting from heart failure and related causes. The model includes inpatient, outpatient, and professional cost estimates based on Medicare claims data, and it is driven by traditional endpoint statistics reported in the clinical trial literature. It provides a common framework for comparing cost effectiveness across clinical trials in the absence of detailed cost information collected in the trial. The incremental expected cost per year of life saved is $3,300 for bisoprolol, $2,500 for metoprolol, and $6,700 for carvedilol. The cost per year of life saved for each compound is well below accepted standards for cost effectiveness. These results are sensitive to the cost of drug therapy and the relative mortality rate for the experimental group. For example, if the relative mortality rate of the experimental group were to increase from the reported 40% to 82%, and if the annual cost of the drug were to decrease from $2,000 to $500, then we estimate that carvedilol would break even and the cost per year of life saved would drop to zero. Whether beta-blocker therapy, as assumed, sustains its differential effectiveness in terms of relative mortality risk beyond the study duration has not been demonstrated.

Cause and management of heart failure in patients with chronic renal disease

Heart failure occurs in 40% of patients with end-stage renal disease and is a major determinant of mortality. Heart failure occurs in patients with left ventricular systolic dysfunction (dilated left ventricle) as well as those with a normal resting ejection fraction (nondilated left ventricle). This report describes the cause of heart failure among patients with end-stage renal disease and the effect of heart failure on survival. We also discuss the impact of renal failure on the medical management of these patients.

Heart failure etiology affects peripheral vascular endothelial function after cardiac transplantation

OBJECTIVES

The goal of this study was to examine the effect of heart failure etiology on peripheral vascular endothelial function in cardiac transplant recipients.

BACKGROUND

Peripheral vascular endothelial dysfunction occurs in patients with heart failure of either ischemic or nonischemic etiology. The effect of heart failure etiology on peripheral endothelial function after cardiac transplantation is unknown.

METHODS

Using brachial artery ultrasound, endothelium-dependent, flow-mediated dilation (FMD) was assessed in patients with heart failure with either nonischemic cardiomyopathy (n = 10) or ischemic cardiomyopathy (n = 7), cardiac transplant recipients with prior nonischemic cardiomyopathy (n = 10) or prior ischemic cardiomyopathy (n = 10) and normal controls (n = 10).

RESULTS

Patients with heart failure with either ischemic cardiomyopathy or nonischemic cardiomyopathy had impaired FMD (3.6 +/- 1.0% and 5.1 +/- 1.2%, respectively, p = NS) compared with normal subjects (13.9 +/- 1.3%, p < 0.01 compared with either heart failure group). In transplant recipients with antecedent nonischemic cardiomyopathy, FMD was markedly higher than that of heart failure patients with nonischemic cardiomyopathy (13.0 +/- 2.4%, p < 0.001) and similar to that of normal subjects (p = NS). However, FMD remained impaired in transplant recipients with prior ischemic cardiomyopathy (5.5 +/- 1.5%, p = 0.001 compared with normal, p = 0.002 vs. transplant recipients with previous nonischemic cardiomyopathy).

CONCLUSIONS

Peripheral vascular endothelial function is normal in cardiac transplant recipients with antecedent nonischemic cardiomyopathy, but remains impaired in those with prior ischemic cardiomyopathy. In contrast, endothelial function is uniformly abnormal for patients with heart failure, regardless of etiology. These findings indicate that cardiac transplantation corrects peripheral endothelial function for patients without ischemic heart disease, but not in those with prior atherosclerotic coronary disease.

Ventricular remodeling and the renin angiotensin aldosterone system

Ventricular remodeling in patients with left ventricular systolic dysfunction is an indolent process that is associated with a poor prognosis. Clinical and experimental data support the central role played by the renin-angiotensin-aldosterone system in the pathophysiology of remodeling. ACE inhibitors improve the natural history of ventricular remodeling and the syndrome of heart failure. Experimental and preliminary clinical data suggest that angiotensin II type I receptor blockade also impacts favorably on remodeling. Some experimental studies suggest a possible synergistic effect when combining ACE inhibitors and angiotensin II type I receptor antagonists. Aldosterone, the regulation of which, in part, is independent of angiotensin II, is a direct mediator of the interstitial component of remodeling, and its blockade has been found to improve clinical outcomes. Future research will more precisely define the mechanism for ventricular remodeling and will yield more effective means of achieving a clinically relevant impact on this process. (c)2000 by CHF, Inc.

Effects of losartan and captopril on left ventricular volumes in elderly patients with heart failure: results of the ELITE ventricular function substudy

BACKGROUND

The mechanism by which angiotensin-converting enzyme inhibitors reduce mortality rates and disease progression in patients with heart failure is likely mediated in part through prevention of adverse ventricular remodeling. This study examined the effects of the angiotensin-converting enzyme inhibitor captopril and the angiotensin II type 1 receptor antagonist losartan on ventricular volumes and function in elderly patients with heart failure and reduced left ventricular ejection fraction (< or =40%).

METHODS

Patients underwent radionuclide ventriculograms (RVG) at baseline and were randomized to either captopril (n = 16) or losartan (n = 13). After 48 weeks, another RVG was obtained. Therapy was then withdrawn for at least 5 days, and the RVG was repeated while the patient was not receiving the drug.

RESULTS

At 48 weeks both captopril and losartan significantly reduced left ventricular (LV) end-diastolic volume index (135 +/- 26 to 128 +/- 23 mL/m(2) for losartan, P <.05 vs baseline; 142 +/- 25 to 131 +/- 20 mL/m(2) for captopril, P <.01; mean (SD). Captopril also reduced LV end-systolic volume index (98 +/- 24 to 89 +/- 21 mL/m(2), P <.01 vs. baseline), whereas a nonsignificant trend was observed for the losartan group (97 +/- 23 to 90 +/- 16 mL/m(2), P = not significant). The between-group differences in the changes in LV volumes were not statistically significant. After drug withdrawal, LV end-diastolic volume index remained significantly lower than baseline in the captopril group (P <.01).

CONCLUSIONS

Both captopril and losartan prevent LV dilation, representing adverse ventricular remodeling, previously seen with placebo treatment. Reverse remodeling was observed in the captopril group. On the basis of these results, the relative effects on LV remodeling do not provide a rationale for a survival benefit of losartan over captopril.

Effect of losartan compared with captopril on mortality in patients with symptomatic heart failure: randomised trial--the Losartan Heart Failure Survival Study ELITE II

BACKGROUND

The ELITE study showed an association between the angiotensin II antagonist losartan and an unexpected survival benefit in elderly heart-failure patients, compared with captopril, an angiotensin-converting-enzyme (ACE) inhibitor. We did the ELITE II Losartan Heart Failure Survival Study to confirm whether losartan is superior to captopril in improving survival and is better tolerated.

METHODS

We undertook a double-blind, randomised, controlled trial of 3,152 patients aged 60 years or older with New York Heart Association class II-IV heart failure and ejection fraction of 40% or less. Patients, stratified for beta-blocker use, were randomly assigned losartan (n=1,578) titrated to 50 mg once daily or captopril (n=1,574) titrated to 50 mg three times daily. The primary and secondary endpoints were all-cause mortality, and sudden death or resuscitated arrest. We assessed safety and tolerability. Analysis was by intention to treat.

FINDINGS

Median follow-up was 555 days. There were no significant differences in all-cause mortality (11.7 vs 10.4% average annual mortality rate) or sudden death or resuscitated arrests (9.0 vs 7.3%) between the two treatment groups (hazard ratios 1.13 [95.7% CI 0.95-1.35], p=0.16 and 1.25 [95% CI 0.98-1.60], p=0.08). Significantly fewer patients in the losartan group (excluding those who died) discontinued study treatment because of adverse effects (9.7 vs 14.7%, p<0.001), including cough (0.3 vs 2.7%).

Effects of amlodipine on exercise tolerance, quality of life, and left ventricular function in patients with heart failure from left ventricular systolic dysfunction

BACKGROUND

A preliminary study suggested that the long-acting late-generation calcium-channel blocker amlodipine has favorable effects on exercise tolerance and is safe to use in heart failure, in contrast to earlier generation agents. The goal of 2 multicenter studies was to assess the effect of adjunctive therapy with amlodipine in addition to standard therapy on exercise capacity, quality of life, left ventricular function, and safety parameters in patients with heart failure and left ventricular systolic dysfunction.

METHODS

Two large multicenter trials examining the effects of amlodipine on these parameters over a 12-week period of therapy were undertaken in patients with mild to moderate heart failure and left ventricular systolic dysfunction. A total of 437 patients with stable heart failure were studied in a randomized, double-blind, placebo-controlled prospective design.

RESULTS

Amlodipine at a dose of 10 mg/day in addition to standard therapy in such patients was associated with no significant difference in change in exercise tolerance on a Naughton protocol compared with placebo in each trial. Among all patients taking amlodipine, exercise time increased 53 +/- 9 (SE) seconds; exercise time for those taking placebo increased 66 +/- 9 seconds (P = not significant). There were no significant differences in changes of quality of life parameters between amlodipine- and placebo-treated patients, and there were no significant differences in symptom scores or New York Heart Association classification between groups. Left ventricular function (measured as ejection fraction) improved 3. 4% +/- 0.5% in amlodipine-treated patients and 1.5% +/- 0.5% in placebo-treated patients (P =.007). There was no statistically significant excess of important adverse events (episodes of worsening heart failure in 10% amlodipine-treated vs 6.3% of placebo-treated patients) or differences in need for changes in background medication between groups.

CONCLUSIONS

The addition of 10 mg of amlodipine per day to standard therapy in patients with heart failure is associated with no significant improvement in exercise time compared with placebo therapy over a 12-week period, and there was no increased incidence of adverse events. These data suggest that the addition of amlodipine to standard therapy in heart failure will not result in additional efficacy per se beyond standard therapy.

Effects of losartan versus captopril on mortality in patients with symptomatic heart failure: rationale, design, and baseline characteristics of patients in the Losartan Heart Failure Survival Study--ELITE II

BACKGROUND

In the Evaluation of Losartan in the Elderly (ELITE) heart failure study, a survival benefit (primarily because of a reduction in sudden deaths) was observed in symptomatic patients treated with losartan compared with captopril.

METHODS AND RESULTS

The Losartan Heart Failure Survival Study--ELITE II (currently ongoing) is a double-blind, randomized clinical trial being conducted in 45 countries at 288 sites. ELITE II formally tests the hypotheses that losartan, compared with captopril, will reduce all-cause mortality (primary end point) and sudden cardiac death and/or resuscitated cardiac arrest (secondary end point). In addition, all-cause mortality and/or hospitalizations and cardiovascular mortality and/or hospitalizations will be evaluated. The trial has 90% power to detect a 25% treatment difference in all-cause mortality (event driven, 510 deaths). Substudies are examining quality of life, health care resource utilization, and mechanisms related to the reduction in sudden death. During recruitment (June 1997 to May 1998), 3,152 patients aged 60 years or older (mean age, 71.6 years), with New York Heart Association classes II (51%), III (44%), and IV (5%), and left ventricular ejection fraction of 40% or less (mean, 31%) were randomized to receive either 12.5 mg of losartan, titrated as tolerated to 50 mg once daily, or 12.5 mg of captopril, titrated as tolerated to 50 mg thrice daily. Randomization was stratified by clinical site and for baseline beta-blocker use.

CONCLUSION

The ELITE II study will further define the role of losartan in the treatment of patients with symptomatic heart failure relative to the angiotensin-converting enzyme inhibitor captopril, an agent from a class currently considered standard treatment for this disease.

Factors influencing exercise performance in patients with left ventricular dysfunction. SOLVD Investigators. Studies of Left Ventricular Dysfunction

BACKGROUND

The determinants of exercise performance are multifactorial and incompletely understood in patients with symptomatic left ventricular (LV) dysfunction, with much less information regarding asymptomatic LV dysfunction. This study assessed the hemodynamics and neurohormonal factors influencing exercise performance in patients with LV ejection fractions > or =0.35, both symptomatic and asymptomatic, enrolled in Studies of LV Dysfunction.

METHODS AND RESULTS

We studied 103 patients enrolled prospectively in Studies of LV Dysfunction before randomized therapy; 38 were symptomatic and 65 had no or minimal symptoms. By using rest-exercise gated equilibrium radionuclide ventriculography and cuff blood pressure, we assessed the heart rate, LV and right ventricular (RV) volumes and ejection fractions, total peripheral resistance, the LV peak systolic pressure/end systolic volume ratio as an index of contractility, and plasma renin and norepinephrine at rest and during maximal graded supine bicycle ergometer exercise. Changes between rest and exercise were evaluated as indices of cardiovascular reserve. The cumulative workload ranged from 120 to 2,100 watt-min. At rest, the LV ejection fraction was 0.30 in asymptomatic patients and 0.25 in symptomatic patients, respectively (P < .0004). During exercise, asymptomatic patients had greater increases in heart rate, systolic blood pressure, LV ejection fraction, and cardiac output than symptomatic patients (P > or = .05). Combining all patients, the strongest univariate correlates of exercise workload were the ability to increase heart rate (r = 0.70), the pressure/volume ratio (r = 0.63), and systolic blood pressure (r = 0.55), and to decrease the total peripheral resistance (r = -0.47) with moderate correlations for the ability to increase LV and RV ejection fractions (r = 0.33 and 0.35, respectively) (P < .0008). By multivariate analysis, workload was modeled best by the changes in four factors: heart rate, systolic blood pressure, and the LV and RV ejection fractions (R2 = 0.54, P < .001).

CONCLUSION

Exercise performance and its hemodynamics differed in patients with symptomatic and asymptomatic LV dysfunction. Rather than features at rest, the reserve capacities for increasing heart rate, systolic blood pressure, and the LV and RV ejection fractions were the predominant cardiac mechanisms related to greater exercise performance.

Treatment guidelines in heart failure

The risk of heart failure increases with age. Prognosis is poor, with 82% of patients dying within 6 years of diagnosis. As the population ages, heart failure is becoming an increasing problem. Heart failure is a complex disease that may be managed in a variety of ways depending on its severity and cause. A wide range of pharmacological and nonpharmacological therapeutic measures are available to relieve symptoms and prolong life. These have changed considerably in the last decade. Cardiology experts in the United States and Europe have developed guidelines for the diagnosis and management of heart failure. These are intended to help physicians to keep up with therapeutic developments and to encourage more appropriate and cost-effective management of patients with heart failure. The European guidelines were updated more recently than their US counterparts and consequently contain certain new developments, such as the inclusion of the latest data on beta-blockers, including carvedilol, that have shown morbidity and mortality rate benefits in patients with mild-to-moderate heart failure. As the management of heart failure is changing rapidly, regular schemes for updating of guidelines are being considered.

Divergent effects of angiotensin-converting enzyme inhibition and angiotensin II-receptor antagonism on myocardial cellular proliferation and collagen deposition after myocardial infarction in rats

There is mechanistic rationale to suggest differential effects of angiotensin-converting enzyme (ACE) inhibition and angiotensin II type 1 (AT1)-receptor antagonism on ventricular remodeling after myocardial infarction (MI). We compared the effects of ACE inhibition, AT1-receptor antagonism, and their combination on post-MI ventricular remodeling in rats. We induced MI in 62 rats, which then received one of four treatments: (a) placebo; (b) the ACE inhibitor, enalapril; (c) the AT1-receptor antagonist, losartan; and (d) enalapril and losartan in combination. Two weeks after MI, we examined: (a) heart weight (HW)/body weight (BW) ratio; (b) nonmyocyte cellular proliferation in the noninfarct zone by using proliferating cell nuclear antigen staining; and (c) collagen content within the noninfarct zone. Placebo-treated, infarcted rats developed significant increases in HW/BW ratio (p < 0.001), left ventricular (LV) volume (p < 0.01), nonmyocyte cellular proliferation (p < 0.04), and collagen content (p < 0.01) compared with noninfarcted controls. Enalapril, losartan, and combination therapy limited the increase in HW/BW ratio (all p values <0.01 vs. placebo). Enalapril inhibited nonmyocyte proliferation (p < 0.01 vs. placebo), whereas losartan had a smaller effect (p = NS vs. placebo; p < 0.03 vs. enalapril); combined treatment also reduced nonmyocyte cellular proliferation but did not reach statistical significance (p = 0.08 vs. placebo). Enalapril and combination treatment significantly diminished collagen content (both p values <0.01 vs. placebo), whereas losartan did not. Thus, ACE inhibition and AT1-receptor antagonism equally limited myocardial hypertrophy after MI in rats, but ACE inhibition more effectively prevented nonmyocyte cellular proliferation and collagen deposition in the noninfarcted myocardium. Combination therapy was no more effective than was ACE inhibition alone. These data suggest that the myocyte hypertrophic response after MI is strongly influenced by activation of the AT1 receptor, whereas nonmyocyte cellular proliferation and collagen deposition result, in part, from mechanisms separate from AT1-receptor activation.

Ventricular remodeling in a mouse model of myocardial infarction

We investigated the suitability of studying ventricular remodeling in a mouse model of myocardial infarction (MI). We performed left coronary ligation (n = 22) or a sham procedure (n = 21) on normal C57BL/6J mice. Six weeks later, animals underwent echocardiography and hemodynamic evaluation. Left ventricular (LV) volume at a common distending pressure was calculated from passive pressure-volume curves. The MI group exhibited lower systolic blood pressure (P < 0.05), higher LV end-diastolic pressure (P < 0.05), and lower peak first derivative of LV pressure (dP/dt, P < 0.05) than the sham group. Mice with moderate (< 40%, n = 11) and large (> or = 40%, n = 11) MIs displayed increased LV mass-to-body weight ratio (P < 0.02 and P < 0.01, respectively, vs. sham group), whereas only the large-MI group exhibited increased right ventricular mass-to-body weight ratio (P < 0.01). LV volumes were increased in the moderate-MI group (P = 0.059 vs. sham group) and to a much greater extent in the large-MI group (P < 0.0001 vs. sham group). The moderate- and large-MI groups also exhibited increases in LV end-diastolic diameter (P < 0.03 and P < 0.0001, respectively, vs. sham group) and LV end-systolic diameter (P < 0.01 and P < 0.0001, respectively, vs. sham group) with decreased fractional shortening (P < 0.01 for both). These data demonstrate ventricular remodeling in a mouse model of MI and confirm the feasibility of quantifying indexes of remodeling in vivo and postmortem. This model will be of particular usefulness when applied to transgenic strains.

Ventricular remodeling and its prevention in the treatment of heart failure

Ventricular remodeling refers to changes in left ventricular (LV) geometry, mass, and volume in response to myocardial injury or alterations in load. The extent of LV dilatation or remodeling after myocardial infarction (MI) or in patients with heart failure is a strong predictor of both morbidity and mortality. Based on these observations, it is clear that LV remodeling is a maladaptive process. Two classes of drugs appear to inhibit LV remodeling. A large amount of data support the use of angiotensin-converting enzyme (ACE) inhibitors to improve survival and to prevent progressive remodeling. In addition, recent studies suggest that beta-adrenergic blockers have a beneficial effect on both survival and remodeling. These data support a causative role of the renin-angiotensin system and perhaps the sympathetic nervous system in this process. Thus, ACE inhibitors and possibly beta-blockers should be part of the pharmacologic regimen for the treatment of patients with LV dysfunction to prevent progressive LV remodeling.

Warfarin anticoagulation and survival: a cohort analysis from the Studies of Left Ventricular Dysfunction

OBJECTIVES

We sought to evaluate the relation between warfarin anticoagulation and survival and morbidity from cardiac disease in patients with left ventricular (LV) dysfunction.

BACKGROUND

Warfarin anticoagulation plays a major role in the management of patients who have had a large myocardial infarction and in those with atrial fibrillation. However, its use in patients with LV systolic dysfunction has been controversial.

METHODS

We reviewed data on warfarin use in 6,797 patients enrolled in the Studies of Left Ventricular Dysfunction (SOLVD) trial and analyzed the relation between warfarin use and all-cause mortality, as well as the combined end point of death or hospital admission for heart failure. We used Cox regression to adjust for differences in baseline characteristics and to test for the interaction between warfarin use and selected patient variables in relation to outcome.

RESULTS

On multivariate analysis, use of warfarin was associated with a significant reduction in all-cause mortality (adjusted hazard ratio [HR] 0.76, 95% confidence interval [CI] 0.65 to 0.89, p = 0.0006) and in the risk of death or hospital admission for heart failure (HR 0.82, 95% CI 0.72 to 0.93, p = 0.0002). Risk reduction was observed when each trial or randomization arm was analyzed separately, as well as in both genders. It was not significantly influenced by the presence of atrial fibrillation, age, ejection fraction, New York Heart Association functional class or etiology.

CONCLUSIONS

In patients with LV systolic dysfunction, warfarin use is associated with improved survival and reduced morbidity. This association is primarily due to a reduction in cardiac events and does not appear to be limited to any particular subgroup.

Antiplatelet agents and survival: a cohort analysis from the Studies of Left Ventricular Dysfunction (SOLVD) trial

OBJECTIVES

This study sought to evaluate the relation between antiplatelet agent (APA) use and survival and morbidity from cardiac disease in patients with left ventricular (LV) systolic dysfunction.

BACKGROUND

APAs play an important role in the prevention and treatment of coronary disease. Their effects in patients with LV systolic dysfunction are unknown.

METHODS

We reviewed data on APA use in 6,797 patients enrolled in the Studies of Left Ventricular Dysfunction (SOLVD) trial and analyzed the relation between their use and all-cause mortality as well as the combined end point of death or hospital admission for heart failure (HF). We used Cox regression to adjust for differences in baseline characteristics and to test for the interaction between APA use and selected patient variables in relation to outcome.

RESULTS

APA use (46.3% of patients) was associated with significantly reduced mortality from all causes (adjusted hazard ratio [HR] 0.82, 95% confidence interval [CI] 0.73 to 0.92, p = 0.0005) and reduced risk of death or hospital admission for HF (adjusted HR 0.81, 95% CI 0.74 to 0.89, p < 0.0001) but was not influenced by trial assignment, gender, LV ejection fraction, New York Heart Association class or etiology. A strong interaction was observed among APA use, randomization group and all-cause mortality. The association between APA use and survival was not observed in the enalapril group, nor was an enalapril benefit on survival detectable in patients receiving APAs at baseline. However, randomization to enalapril therapy significantly reduced the combined end point of death or hospital admission for HF in APA users.

CONCLUSIONS

In patients with LV systolic dysfunction, use of APAs is associated with improved survival and reduced morbidity. This association is retained after adjustment for baseline characteristics. APA use is associated with retained but reduced benefit from enalapril.

Pharmacotherapy for systolic dysfunction: a review of randomized clinical trials

Chronic heart failure (HF) is a leading cause of morbidity and mortality in the United States, affecting >4 million people. The increasing prevalence of HF has placed an enormous burden on the US healthcare system. For many patients with cardiovascular disease, HF is the final common pathway. Treatment strategies for HF are aimed at preventing and delaying progression of the disease and ultimately improving survival. This article reviews recent clinical drug trials for HF, including angiotensin-converting enzyme (ACE) inhibitors, angiotensin II antagonists, vasodilators, beta-adrenergic blockers, positive inotropic agents, calcium antagonists, and antiarrhythmics. The benefits and shortcomings of these agents and the study designs are discussed. For patients with left ventricular (LV) systolic dysfunction, ACE inhibitors are the only agents that consistently improved survival and decreased the rate of HF progression. It is likely that beta-adrenergic blockers have the same effect. The syndrome of HF is complex with both peripheral and cardiac factors contributing to disease progression. The addition of a diuretic and/or digoxin is often needed to prevent worsening heart failure. Although an angiotensin II antagonist may also be beneficial in the treatment of HF, further studies are needed to clarify their precise role in the management of this condition. Calcium anatagonists, antiarrhythmics excluding amiodarone, and positive inotropes other than digoxin do not appear to prevent progression of HF nor improve survival. The most common cause of HF in the United States is related to coronary artery disease. Reduction of cardiac risk factors, such as smoking cessation, lowering serum cholesterol with diet and a lipid lowering agent, and blood pressure control, is likely to prevent the development or progression of HF.

Acute and long-term effects of the angiotensin-converting enzyme inhibitor, enalapril, on adrenergic activity and sensitivity during exercise in patients with left ventricular systolic dysfunction

Patients with heart failure and left ventricular systolic dysfunction exhibit increased adrenergic activity but blunted adrenergic responsiveness. We studied patients enrolled in the Studies of Left Ventricular Dysfunction, examining exercise responses of heart rate (HR) and plasma norepinephrine (PNE). Eighty-seven patients were studied before randomization; 65 of these were examined 1 year after randomization to placebo or enalapril. Compared with prevention trial (asymptomatic) patients, patients in the treatment trial (symptomatic) had higher resting HR and PNE levels and less increase in HR with a greater increase in PNE with exercise. Acute administration of enalapril increased the resting HR in patients in the prevention trial only but had no significant effect on PNE. After 1 year of therapy, patients in the prevention trial exhibited no change. Within the treatment trial, the placebo group displayed both a higher peak PNE and increase in PNE with exercise than did the enalapril group, whose HR response was maintained in spite of a reduction of exercise PNE. We conclude that (1) compared with asymptomatic patients, symptomatic patients with reduced left ventricular ejection fraction manifest greater resting and exercise adrenergic activity, with blunted HR response; and (2) in symptomatic patients, 1 year of enalapril treatment effected an augmented HR response to adrenergic stimulation, supporting an interaction between the renin/angiotensin and adrenergic nervous systems. Normalization of adrenergic tone and response likely contributes to the benefits of long-term angiotensin-converting enzyme inhibitor therapy.

New trends in the interventional treatment of ischaemic heart disease

Direct revascularization of an ischaemic vascular bed represents an attractive treatment option for patients with coronary artery disease. Coronary artery bypass surgery has been demonstrated to provide both symptomatic improvement and, in certain circumstances, to improve prognosis, while catheter-based techniques offer substantial improvement in symptomatology, with reduced morbidity compared with bypass surgery. Although balloon angioplasty has been associated with lesion success rates approximating to 89%, a number of anatomical substrates have proved refractory to this approach and restenosis remains a significant problem. Newer interventional modalities, such as directional atherectomy, rotablation, transluminal extraction catheterization, laser coronary angioplasty and coronary stenting, all have the potential to offer improved rates of restenosis under specific circumstances. With the exception of stents, most have not been shown to provide an overall improvement in rates of restenosis. Numerous pharmacological agents have also been investigated in an attempt to reduce levels of restenosis. Calcium channel blockers have been assessed in five trials, none of which has demonstrated a conclusive benefit, although meta-analysis of the data generated in these trials has shown a 30% reduction in the likelihood of restenosis associated with their use. More recently, monoclonal antibodies to glycoprotein IIb/IIIa have been linked to a reduction in restenosis.

Combined analysis of resting regional wall thickening and stress perfusion with electrocardiographic-gated technetium 99m-labeled sestamibi single-photon emission computed tomography: prediction of stress defect reversibility

BACKGROUND

The high photon flux and stable distribution of the myocardial perfusion agent 99mTc-labeled sestamibi allow the perfusion data to be acquired in an electrocardiographic (ECG)-gated mode, such that information on resting regional wall thickening may be obtained simultaneously with stress perfusion data. The objective of this study was to assess whether visual analysis of resting regional wall thickening provided by ECG-gated acquisition of 99mTc-labeled sestamibi stress perfusion images correlates with and predicts the reversibility of stress-induced perfusion defects, potentially obviating the need for rest imaging.

METHODS AND RESULTS

Fifty-nine patients referred for myocardial perfusion imaging were studied with rest and stress single-photon emission computed tomographic (SPECT) sestamibi imaging, and the stress perfusion data were acquired in an ECG-gated mode. Visual analysis of the presence and reversibility of stress perfusion defects on standard imaging was correlated with the wall thickening data from the poststress gated SPECT images. Quantitative circumferential profile analysis of the short-axis images was performed to assess the influence of relative stress perfusion defect severity on the correlation between wall thickening and defect reversibility. Among the 72 segments with stress-induced perfusion defects and visually apparent wall thickening on ECG-gated SPECT images, 69 were reversible on rest imaging (positive predictive value of 96% for wall thickening to predict stress defect reversibility). Of the 35 segments with stress-induced defects and no apparent wall thickening on ECG-gated SPECT images, however, 14 (40%) demonstrated significant stress defect reversibility on rest imaging. This result represents a negative predictive value of only 60% for the lack of apparent wall thickening to predict correctly an irreversible stress defect. Among the segments with reversible stress perfusion defects and visually apparent wall thickening, relative stress sestamibi activity was higher (51% +/- 10% [percentage of peak]) than in segments with reversible stress defects and no visually apparent wall thickening (39% +/- 4% of peak activity [p < 0.0001]).

CONCLUSIONS

Visual evidence of wall thickening by poststress ECG-gated SPECT sestamibi imaging in the territory of a stress-induced perfusion defect correlates highly with stress defect reversibility on rest imaging and may obviate the need to perform rest imaging, thereby potentially reducing the time and cost involved in myocardial perfusion imaging. The absence of visually apparent wall thickening, however, underestimates the prevalence of stress defect reversibility on rest imaging; in such instances, rest imaging must be performed to differentiate ischemia from infarction in the territory of a stress perfusion defect.

Calcium channel blockers in heart failure: help or hindrance?

Since their development, calcium channel blocking agents have stimulated interest in their potential benefit for a variety of cardiovascular disorders, including heart failure. The rationale for the potential benefit of calcium channel blockers in heart failure is multi-factorial, including vasodilation, correction of perturbed diastolic relaxation, anti-ischemic action, and potential for inhibiting myocyte hypertrophy and injury. Despite these potential benefits, the degree of salutary influence has remained controversial, and a number of studies have suggested potential adverse action in patients with heart failure, perhaps linked to either negative inotropic action or to reflex neurohormonal activation. Diversity among different agents, particularly with regard to tissue selectivity and pharmacokinetics may imply substantial differences in the relative benefits and risks in various subgroups of patients with heart failure. One trial with the newer dihydropyridine agent, amlodipine, indicates benefit to survival in patients with moderate to severe heart failure and reduced ejection fraction. The reproducibility of this finding and the mechanism for this benefit deserves further investigation.

Baseline quality of life as a predictor of mortality and hospitalization in 5,025 patients with congestive heart failure. SOLVD Investigations. Studies of Left Ventricular Dysfunction Investigators

This study examined the independent relation of health-related quality of life (HRQL) to mortality and congestive heart failure (CHF)-related hospitalizations in patients with an ejection fraction of < 0.35 followed for a mean of 36.5 months. A brief HRQL questionnaire was administered at baseline to patients randomized to placebo or enalapril in the Studies of Left Ventricular Dysfunction (SOLVD) trial. Participants had an ejection fraction of < 0.35 and either symptomatic CHF (treatment trial, n = 2,465) or asymptomatic CHF (prevention trial, n = 2,560). Baseline assessment of HRQL predicted mortality and CHF-related hospitalizations in symptomatic and asymptomatic patients randomized to enalapril and placebo treatment. Domains that were the stronger univariate predictors of mortality and CHF-related hospitalizations were activities of daily living (relative risk [RR] for mortality: 1.163, p < 0.000; for hospitalization: 1.215, p < 0.000), general health (RR for mortality: 1.205, p < 0.000; for hospitalization: 1.188, p < 0.000), and social functioning (RR for mortality 1.098, p < 0.000; for hospitalization: RR 1.156, p < 0.000). In the multivariate model, activities of daily living (RR for mortality 1.41, p < 0.000; for hospitalization: RR 1.43, p < 0.002), general health (RR for mortality 1.21, p < 0.000; for hospitalization RR 1.16, p < 0.013) and heart failure symptoms (RR for mortality 1.02, p < 0.025; for hospitalization RR 1.03, p < 0.004) were found to be independent risk factors. HRQL independently predicted mortality and CHF-related hospitalizations after adjustment for ejection fraction, age, treatment, and New York Heart Association classification in patients with an ejection fraction of < 0.35, randomized to enalapril and placebo treatment. HRQL provides additional clinical information regarding disease course and outcome that is not captured by traditional indexes of clinical status.

Effects of renal neutral endopeptidase inhibition on sodium excretion, renal hemodynamics and neurohormonal activation in patients with congestive heart failure

We investigated the effects of inhibiting endogenous atrial natriuretic factor (ANF) metabolism on renal hemodynamics, sodium excretion and neurohormones in 12 patients with New York Heart Association functional class II congestive heart failure (CHF) due to left ventricular systolic dysfunction. In a randomized, placebo-controlled, double-blinded fashion, 8 patients received a single oral dose of candoxatril, an inhibitor of renal neutral endopeptidase, and 4 patients received placebo. Candoxatril treatment increased plasma ANF by 70 +/- 71 pg/ml (p < 0.015 vs. placebo) and plasma cGMP by 7.9 +/- 2.7 pmol/ml (p < 0.001 vs. placebo), with maximal effects at 3.5 h. Urinary cGMP more than doubled (p = 0.025 vs. placebo). Candoxatril increased urinary sodium by 2.7 +/- 2.0 mEq/h (p < 0.05 vs. placebo) and significantly elevated filtration fraction with no significant effect on glomerular filtration rate, renal plasma flow or lithium clearance. A significant reduction in aldosterone concentration with a similar trend in plasma renin activity was noted in candoxatril-treated patients. Thus in patients with moderate heart failure, renal neutral endopeptidase inhibition increases urinary sodium excretion. The lack of an effect on renal hemodynamics suggests that this natriuresis results from ANF-mediated inhibition of tubular sodium reabsorption. These findings justify additional investigation into potential clinical benefit of endopeptidase inhibition in patients with CHF.

Angiotensin converting enzyme inhibition in asymptomatic left ventricular systolic dysfunction and early heart failure

Benefit achieved through use of angiotensin converting enzyme (ACE) inhibitors in patients with reduced left ventricular (LV) systolic function is not confined to those with clinical manifestations of heart failure. Although rates of adverse clinical events are lower in asymptomatic patients, within this population ACE inhibitors have been shown to prevent adverse ventricular remodelling, prevent the development of clinical heart failure, reduce rates of hospitalization for heart failure and, in some studies, reduce mortality. Most of the benefit derived appears to be associated with preventing the progression of LV hypertrophy, dilatation, and dysfunction, resulting in prevention of heart failure. Additionally, the incidence of myocardial infarction is decreased, although the exact physiological basis for this benefit remains uncertain. Given the enormity and growth of heart failure as a public health problem and the potential for influencing the underlying pathophysiology, ACE inhibitor treatment offers substantial benefit for patients with asymptomatic LV systolic dysfunction.

Enhanced hepatic uptake of thallium-201 in patients with severe narrowing of the right coronary artery

To assess the hepatic uptake of thallium-201 after exercise treadmill testing and to investigate whether hepatic uptake of thallium-201 may be a useful marker of right coronary artery (RCA) disease, 43 patients were studied: 17 with RCA disease (9 with 1-vessel disease, 8 with multivessel disease including the RCA), 8 with left coronary system disease alone, and 18 with a low probability (< 5%) of coronary disease. All subjects were studied with symptom-limited exercise and redistribution thallium-201 single-photon emission computed tomographic (SPECT) scintigraphy. Two indexes of hepatic uptake were derived: a liver-to-heart ratio after stress, and a stress-to-rest hepatic ratio. The low-probability group had a liver/heart ratio of 0.48 +/- 0.02. In the group with RCA disease alone, liver/heart ratio was 1.29 +/- 0.20 (p < 0.005 vs low-probability group). Patients with multivessel coronary artery disease involving the RCA had a ratio of 1.19 +/- 0.16 (p < 0.005 vs low-probability group), and patients with only left coronary system disease had a liver/heart ratio of 0.87 +/- 0.15 (p < 0.05 vs low-probability group). The stress/rest ratio of the low-probability group was 0.83 +/- 0.04. Patients with RCA disease alone had a stress/rest ratio of 1.49 +/- 0.25 (p < 0.05 vs low-probability group), and patients with multivessel disease involving the RCA had a stress/rest ratio of 1.16 +/- 0.08 (p < 0.005 vs low-probability group).(ABSTRACT TRUNCATED AT 250 WORDS)

Role of angiotensin converting enzyme inhibitors in preventing left ventricular remodelling following myocardial infarction

Progressive changes typically occur in left ventricular (LV) architecture following moderate- to large-sized myocardial infarction (MI). These changes include early expansion and thinning of the infarct zone and subsequent increase in myocardial mass within the non-infarcted zone, with LV dilatation and loss of the normal elliptical configuration of the LV cavity. These changes are accompanied by impaired myocyte function and advancing clinical expression of heart failure. Numerous animal and human studies have documented inhibition of LV remodeling post-MI by angiotensin converting enzyme (ACE) inhibitors. Although the ideal timing for initiating treatment remains uncertain, evidence exists that benefit persists long after the time of initial injury. Mechanisms for the effects of ACE inhibitors on LV remodelling may be dependent on changes in myocardial load, may be load independent, or both. These effects are likely to be mediated by reductions in circulating and local tissue concentrations of angiotensin II and in bradykinin degradation. Regardless of the exact mechanism or mechanisms by which ACE inhibitors exert their favourable influence on LV remodelling, it is likely that this effect is a key mediator of the documented clinical benefits afforded by treatment with this class of agents.

Effect of long-term enalapril therapy on neurohormones in patients with left ventricular dysfunction. SOLVD Investigators

The aim of this study was to compare the long-term effects of treatment with enalapril or placebo on plasma neurohormones in patients with left ventricular (LV) dysfunction. Elevated neurohormonal levels are associated with increased mortality in patients with congestive heart failure. Multiple studies have shown that angiotensin-converting enzyme inhibitors decrease mortality and morbidity in these patients. In Studies of Left Ventricular Dysfunction (SOLVD), enalapril significantly reduced mortality in patients with symptomatic LV dysfunction (treatment trial). In contrast, in patients with asymptomatic LV dysfunction (prevention trial), there was no significant reduction in mortality with enalapril therapy. The effect of enalapril was examined in 333 prevention trial and 129 treatment trial patients. Plasma norepinephrine (NE) and plasma renin activity were measured in these patients at baseline, and at 4 and 12 months of follow-up. In a subset of these patients, atrial natriuretic peptide (ANP) and arginine vasopressin were also measured. Analysis of covariance models were used to determine the effect of enalapril on each neurohormone. Participants in the treatment trial had significantly higher neurohormonal levels when compared with those in the prevention trial or normal control subjects. In the treatment trial, patients taking enalapril had a greater decrease in plasma NE levels than patients taking placebo (p < 0.08).(ABSTRACT TRUNCATED AT 250 WORDS)

Heart failure in women

Observational and other studies suggest gender-related differences in the incidence and prognosis of heart failure. Women appear to live longer after the diagnosis of heart failure when compared with men. After myocardial infarction, women seem more likely than men to exhibit clinical heart failure. Diabetes appears to promote heart failure to a greater extent in women than in men. Review of data from clinical and epidemiologic studies suggests that men and women may differ in their myocardial adaptation to a variety of cardiac insults. Future investigation is necessary to better define gender-related differences and possible sex-specific therapies for those diseases resulting in heart failure.

Management of heart failure. III. The role of revascularization in the treatment of patients with moderate or severe left ventricular systolic dysfunction

OBJECTIVE

This article reviews the benefits and risks of coronary artery bypass grafting and angioplasty for patients with moderate or severe left ventricular systolic dysfunction and summarizes the recommendations of the expert panel for the Agency for Health Care Policy and Research Heart Failure Guideline.

DATA SOURCES

Data were obtained from studies published in English and referenced in MEDLINE or EMBASE between 1966 and 1993. We used the search terms heart failure, congestive; congestive heart failure; heart failure; cardiac failure; and dilated cardiomyopathy in conjunction with the terms coronary artery bypass grafting and angioplasty.

STUDY SELECTION

All cohort studies and case series that provided separate outcomes data on a subgroup of patients with a left ventricular ejection fraction less than 0.40 were reviewed.

DATA EXTRACTION AND SYNTHESIS

Studies were reviewed for inclusion and exclusion criteria, survival, and functional status measures using a standardized form. Cohort studies were assessed on eight aspects of study quality using a defined list of study flaws.

CONCLUSION

Coronary artery bypass grafting improves 3-year survival by approximately 30% to 50% and physical functioning by approximately one New York Heart Association class in patients with moderate to severe left ventricular dysfunction and limiting angina. However, the operative mortality ranges from 5% to 30% depending on patients' ejection fractions and comorbidity. It is not clear whether patients whose predominant symptom is heart failure rather than angina benefit from bypass surgery or how much ischemia is required to justify surgical intervention. Clinical outcomes after angioplasty have not been adequately studied to determine the relative risks and benefits compared with bypass grafting.

Management of heart failure. I. Pharmacologic treatment

OBJECTIVE

This review of the pharmacologic treatment of heart failure due to left ventricular systolic dysfunction summarizes the recommendations of the expert panel for the Agency for Health Care Policy and Research Heart Failure Guideline. It provides specific advice to help guide practitioners through clinical decision making.

DATA SOURCES

Data were obtained from English-language studies and referenced in MEDLINE or EMBASE between 1966 and 1993. We used the search terms heart failure, congestive; congestive heart failure; heart failure; cardiac failure; and dilated cardiomyopathy in conjunction with terms for the specific treatments. Where data were lacking, we relied on opinions of panel members and peer reviewers.

STUDY SELECTION

Only large prospective trials were used to estimate treatment efficacy. Smaller trials, case series, and case reports were reviewed for the incidence of adverse effects.

DATA EXTRACTION AND SYNTHESIS

Randomized clinical trials were reviewed for inclusion and exclusion criteria, patient outcomes, adverse effects, and eight categories of study quality using a defined list of study flaws.

CONCLUSION

Angiotensin-converting enzyme (ACE) inhibitors should be given to all patients unless specific contraindications exist. Diuretics should be used judiciously early in treatment to prevent excessive diuresis that could prevent titration of ACE inhibitors to target doses. Digoxin has not been shown to affect the natural history of heart failure and should be reserved for patients who remain symptomatic after treatment with ACE inhibitors and diuretics. Isosorbide dinitrate and hydralazine hydrochloride should be tried in patients who cannot tolerate ACE inhibitors or who have refractory symptoms.

Predicting recovery of severe regional ventricular dysfunction. Comparison of resting scintigraphy with 201Tl and 99mTc-sestamibi

BACKGROUND

Regional 201Tl activity after resting injection, imaged early and after redistribution, reflects viable myocardium and can predict improved isotope uptake as well as regional and global ventricular function after revascularization. 99mTc-sestamibi, a perfusion tracer with favorable imaging characteristics, has distinct kinetics compared with 201Tl, demonstrating minimal redistribution; this property may give 201Tl an advantage for detecting viable myocardium, particularly in segments with resting hypoperfusion. The purpose of this study was to compare regional activities of 201Tl and 99mTc-sestamibi after resting injections in patients with coronary artery disease and regional or global left ventricular dysfunction and to assess their comparative abilities for predicting recovery of severe regional ventricular dysfunction after revascularization.

METHODS AND RESULTS

Qualitative and quantitative comparisons of rest and redistribution 201Tl activity and sestamibi activity 1 hour after rest injection were performed in 31 patients with coronary artery disease and left ventricular dysfunction. Quantitative analysis of three short-axis tomograms per patient was performed by use of circumferential profiles that allowed analysis of 12 segments per patient. Two-dimensional echocardiography was used to assess wall motion and thickening in segments corresponding to the single photon emission computed tomography data. Concordance between regional 201Tl activity at redistribution imaging and regional sestamibi activity by semiquantitative visual analysis demonstrated concordant regional activity in 87% of segments; among discordant segments, no significant skew was seen, indicating enhanced uptake of one agent over the other. Quantitative analysis for all segments showed significant correlation (r = .86, P < .001) between quantitative regional 201Tl redistribution activity and 1-hour post-rest injection sestamibi activity in individual segments. Eighteen of these patients were revascularized, and echocardiography was repeated 20 +/- 16 days later; segments exhibiting significant regional ventricular dysfunction before revascularization were classified as having reversible or irreversible dysfunction on the basis of the change in wall motion and thickening. 201Tl and sestamibi regional activities were similar in those segments with reversible (72 +/- 11% [percent of peak activity] versus 75 +/- 9%, respectively, P = NS) as well as irreversible ventricular dysfunction (51 +/- 11% versus 50 +/- 8%, P = NS). Positive (75% versus 80% for 201Tl and sestamibi, respectively) and negative (92% versus 96%, respectively) predictive values for recovery of regional ventricular dysfunction after revascularization were similar for the two agents.

CONCLUSIONS

In patients with coronary artery disease and left ventricular dysfunction, quantified sestamibi activity 1 hour after rest injection parallels redistribution 201Tl activity after a resting injection, suggesting that uptake and subsequent handling of sestamibi are more complex than can be explained by a pure flow tracer with no redistribution. Quantitative analysis of regional activities of both 201Tl and sestamibi after resting injections can differentiate viable from nonviable myocardium, and the two agents comparably predict reversibility of significant regional wall motion abnormalities after revascularization in such patients to a similar degree.