Sex-Related Differences in Long-Term Outcomes After Early-Onset Myocardial Infarction

Importance

There is growing awareness of sex-related differences in cardiovascular risk profiles, but less is known about whether these extend to pre-menopausal females experiencing an early-onset myocardial infarction (MI), who may benefit from the protective effects of estrogen exposure.

Methods

A nationwide study involving 125 Italian Coronary Care Units recruited 2,000 patients between 1998 and 2002 hospitalized for a type I myocardial infarction before the age of 45 years (male, n = 1,778 (88.9%). Patients were followed up for a median of 19.9 years (IQR 18.1–22.6). The primary composite endpoint was the occurrence of cardiovascular death, non-fatal myocardial re-infarction or non-fatal stroke, and the secondary endpoint of hospitalization for revascularisation by means of a percutaneous coronary intervention (PCI) or coronary artery bypass surgery (CABG).

Results

ST-elevation MI was the most frequent presentation among both men and women (85.1 vs. 87.4%, p = ns), but the men had a greater baseline coronary atherosclerotic burden (median Duke Coronary Artery Disease Index: 48 vs. 23; median Syntax score 9 vs. 7; both p < 0.001). The primary composite endpoint occurred less frequently among women (25.7% vs. 37.0%; adjusted hazard ratio: 0.69, 95% CI 0.52–0.91; p = 0.01) despite being less likely to receive treatment with most secondary prevention medications during follow up.

Conclusions

There are significant sex-related differences in baseline risk factors and outcomes among patients with early-onset MI: women present with a lower atherosclerotic disease burden and, although they are less frequently prescribed secondary prevention measures, experience better long-term outcomes.

Trial Registration

4272/98 Ospedale Niguarda, Ca' Granda 03/09/1998.

Long-term outcomes of early-onset myocardial infarction with non-obstructive coronary artery disease (MINOCA)

BACKGROUND

Acute myocardial infarction with non-obstructive coronary artery disease (MINOCA) is frequent in patients experiencing an early-onset MI, but data concerning its long-term prognosis are limited and conflicting.

METHODS

The Italian Genetic Study on Early-onset MI enrolled 2000 patients experiencing a first MI before the age of 45 years, and had a median follow-up of 19.9 years. The composite primary endpoint was cardiovascular (CV) death, non-fatal MI, and non-fatal stroke (MACE); the secondary endpoint was rehospitalisation for coronary revascularisation.

RESULTS

MINOCA occurred in 317 patients (15.9%) and, during the follow-up, there was no significant difference in MACE rates between them and the patients with obstructive coronary artery disease (MICAD: 27.8% vs 37.5%; adjusted hazard ratio [HR] 0.79, 95% confidence interval [CI] 0.57-1.09;p = 0.15). The CV death rate was lower in the MINOCA group (4.2% vs 8.4%, HR 0.26, 95%CI 0.08-0.86;p = 0.03), whereas the rates of non-fatal reinfarction (17.3% vs 25.4%; HR 0.76, 95%CI 0.52-1.13;p = 0.18), non-fatal ischemic stroke (9.5% vs 3.7%; HR 1.79, 95%CI 0.87-3.70;p = 0.12), and all-cause mortality (14.1% vs 20.7%, HR 0.73, 95%CI 0.43-1.25;p = 0.26) were not significantly different in the two groups. The rate of rehospitalisation for coronary revascularisation was lower among the MINOCA patients (6.7% vs 27.7%; HR 0.27, 95% CI 0.15-0.47;p < 0.001).

CONCLUSIONS

MINOCA is frequent and not benign in patients with early-onset MI. Although there is a lower likelihood of CV death,the long-term risk of MACE and overall mortality is not significantly different from that of MICAD patients.

A 23bp Insertion in the Endothelial Protein C Receptor (EPCR) Gene Impairs EPCR Function

EPCR is a type I transmembrane protein, highly expressed on the endothelium of large vessels, that binds protein C and augments its activation. In this study, a 23bp insertion in the EPCR gene was found in 4/198 survivors of myocardial infarction and 3/194 patients with deep vein thrombosis. The EPCR gene with the insertion predicts a protein that lacks part of the extracellular domain, the transmembrane domain and the cytoplasmic tail. Expression studies showed that the truncated protein is not localized on the cell surface, cannot be secreted in the culture medium, and does not bind activated protein C. Since protein C activation depends on the concentration of EPCR, patients with the EPCR insertion could have a diminished protein C activation capacity. Further clinical studies of adequate samples size are necessary to establish whether or not the EPCR insertion predisposes to the development of thrombotic events.

Influence of 9p21.3 genetic variants on clinical and angiographic outcomes in early-onset myocardial infarction

OBJECTIVES

The purpose of this study was to test whether the 9p21.3 variant rs1333040 influences the occurrence of new cardiovascular events and coronary atherosclerosis progression after early-onset myocardial infarction.

BACKGROUND

9p21.3 genetic variants are associated with ischemic heart disease, but it is not known whether they influence prognosis after an acute coronary event.

METHODS

Within the Italian Genetic Study of Early-onset Myocardial Infarction, we genotyped rs1333040 in 1,508 patients hospitalized for a first myocardial infarction before the age of 45 years who underwent coronary angiography without index event coronary revascularization. They were followed up for major cardiovascular events and angiographic coronary atherosclerosis progression.

RESULTS

Over 16,599 person-years, there were 683 cardiovascular events and 492 primary endpoints: 77 cardiovascular deaths, 223 reoccurrences of myocardial infarction, and 383 coronary artery revascularizations. The rs1333040 genotype had a significant influence (p = 0.01) on the primary endpoint, with an adjusted hazard ratio of 1.19 (95% confidence interval [CI]: 1.08 to 1.37) for heterozygous carriers and 1.41 (95% CI: 1.06 to 1.87) for homozygous carriers. Analysis of the individual components of the primary endpoints provided no significant evidence that the rs1333040 genotype influenced the hazard of cardiovascular death (p = 0.24) or the reoccurrence of myocardial infarction (p = 0.57), but did provide significant evidence that it influenced on the hazard of coronary revascularization, with adjusted heterozygous and homozygous ratios of 1.38 (95% CI: 1.17 to 1.63) and 1.90 (95% CI: 1.36 to 2.65) (p = 0.00015), respectively. It also significantly influenced the angiographic endpoint of coronary atherosclerosis progression (p = 0.002).

CONCLUSIONS

In early-onset myocardial infarction, the 9p21.3 variant rs1333040 affects the progression of coronary atherosclerosis and the probability of coronary artery revascularization during long-term follow-up.

Genome-wide association of early-onset myocardial infarction with single nucleotide polymorphisms and copy number variants

We conducted a genome-wide association study testing single nucleotide polymorphisms (SNPs) and copy number variants (CNVs) for association with early-onset myocardial infarction in 2,967 cases and 3,075 controls. We carried out replication in an independent sample with an effective sample size of up to 19,492. SNPs at nine loci reached genome-wide significance: three are newly identified (21q22 near MRPS6-SLC5A3-KCNE2, 6p24 in PHACTR1 and 2q33 in WDR12) and six replicated prior observations (9p21, 1p13 near CELSR2-PSRC1-SORT1, 10q11 near CXCL12, 1q41 in MIA3, 19p13 near LDLR and 1p32 near PCSK9). We tested 554 common copy number polymorphisms (>1% allele frequency) and none met the pre-specified threshold for replication (P < 10(-3)). We identified 8,065 rare CNVs but did not detect a greater CNV burden in cases compared to controls, in genes compared to the genome as a whole, or at any individual locus. SNPs at nine loci were reproducibly associated with myocardial infarction, but tests of common and rare CNVs failed to identify additional associations with myocardial infarction risk.

Anti-beta 2 glycoprotein I antibodies and the risk of myocardial infarction in young premenopausal women

BACKGROUND

Contrasting data have been reported on the association between the presence of anti-phospholipid antibodies (aPL) and arterial thrombotic events, particularly those in coronary arteries. This discrepancy is perhaps related to the confounding effect of traditional risk factors. Among them, coronary atherosclerosis appears to be the most important in studies conducted in middle-aged and elderly patients.

OBJECTIVE

To minimize such confounding effects, a multicenter case-control study on the association between aPL and myocardial infarction (MI) was carried out in a rare cohort of young premenopausal women.

METHODS

We evaluated 172 cases hospitalized for a first MI before the age of 45 years and 172 controls individually matched with cases for age, sex and geographical origin. Clinical and laboratory data were collected and levels of anti-cardiolipin (aCL), anti-beta2 glycoprotein I (anti-beta2GPI) and anti-nuclear antibodies (ANA) were measured.

RESULTS

A significant association between MI and IgG/IgM anti-beta2GPI antibodies was observed; the results were confirmed after adjusting for smoking and hypertension (anti-beta2GPI IgG OR = 2.47, 95% CI 1.81-3.38; anti-beta2GPI IgM 4th quartile OR 3.68, 95% CI 1.69-8.02). The association between anti-beta2GPI antibodies and MI was detected in both subgroups with and without coronary artery stenosis. Whereas the association of aCL IgG with MI was modest, ANA showed no significant association with MI. No aPL were found in unselected patients (mainly males) who recently developed acute MI.

CONCLUSIONS

Anti-beta2GPI antibodies are a significant risk factor for MI in young premenopausal women independently of other risk factors, including the degree of coronary artery stenosis.

Significance of total and differential leucocyte count in patients with acute myocardial infarction treated with primary coronary angioplasty

AIMS

The aim of this study was to correlate total and differential leucocyte (WBC) count with myocardial blush, peak CK levels, and left ventricular (LV) functional recovery at 6 months in 238 consecutive acute myocardial infarction (MI) patients treated with successful primary coronary angioplasty (PCI).

METHODS AND RESULTS

Total and differential WBC counts were measured on admission and every 24 h for at least 4 days after PCI. ST-segment resolution and myocardial blush were evaluated immediately after successful primary PCI. LV functional recovery (defined as improvement involving at least two segments, or at least one segment, when only two were asynergic on the basal examination) was obtained through echocardiographic evaluation of LV wall motion at the baseline and at 6 months. Basal CK (P<0.001) and increased neutrophil levels (P<0.001) were the only independent factors related to peak CK, whereas neutrophils and monocytes peaks were related to ST-segment resolution as well as to myocardial blush grade (MBG) 2-3. MBG 2-3 and monocytes number (both as continuous values as well as percentile values) were the only variables independently associated with 6-month LV functional recovery.

CONCLUSION

The present study shows that neutrophils and monocytes counts on the first days after acute MI treated with primary PCI are related to markers of effective myocardial reperfusion such as MBG 2-3 and ST-segment resolution. However, only monocytes and MBG are significantly and independently associated with contractile recovery of the infarcted area at 6 months.

Effect of a short antibiotic treatment with roxithromycin on circulating adhesion molecules after coronary stenting: a single-center pilot trial

BACKGROUND

The aim of this study was to assess the effect of periprocedural antibiotic treatment with roxithromycin on circulating cell adhesion molecules and restenosis after coronary stent implantation.

METHODS

Case-control study enrolling 25 consecutive patients submitted to coronary stenting for stable, single-vessel coronary artery disease, treated with 300 mg roxithromycin once daily for 5 days, starting 2 days before the procedure (group R). Twenty-five patients, matched for lesion site, length and diameter, as control group (group C). The serological status for Chlamydia pneumoniae (CP) infection (IgG, ELISA) was assessed in all patients. The plasma concentrations of soluble intercellular adhesion molecule-1 (sICAM-1), E-selectin and C-reactive protein at 1 month after coronary stenting were compared with baseline values. Binary restenosis (> or = 50%) was also evaluated at 6 months.

RESULTS

sICAM-1 significantly decreased at 1 month in group R vs group C (371 +/- 181 vs 573 +/- 273 ng/ml, p = 0.005). This decrease was more evident in patients with a positive serology for CP (CP+) (group R 373 +/- 131 vs group C 597 +/- 255 ng/ml, p = 0.014). Antibiotic treatment had no effects on circulating E-selectin levels at 1 month (56.7 +/- 97 vs 49.8 +/- 62 ng/ml, p = 0.54). The restenosis rate (9/50, 18%) was similar in the two groups (group R 5/25 [20%], group C 4/25 [16%]). The restenosis rate was similar in the CP+ vs CP- group (6/35 [17%] vs 3/15 [20%]).

CONCLUSIONS

A short course of treatment with roxithromycin at the time of coronary stenting induces a significant reduction in the sICAM-1 levels at 1 month but apparently does not influence the restenosis rate.

["Cure" and "tactics" interventional strategies in unstable angina/non-Q infarction]

Early risk stratification and an invasive approach (coronary angiography and reperfusion if indicated) have recently emerged as the treatment of choice in non-ST elevation acute coronary syndromes. An aggressive pharmacologic therapy, i.e. glycoprotein IIb/IIIa antagonists, is also more effective in case of risk assessment at the time of the admission of the patient in the coronary care unit. Recent data have assessed the advantages of abciximab over tirofiban in unstable patients submitted to percutaneous coronary intervention (PCI), whereas non-anticorpal molecules (tirofiban, integrilin) are indicated for the medical treatment of high-risk patients in order to reduce myocardial necrosis during the acute phase. A good platelet inhibition with the oral tienopiridine derivative clopidogrel, resulted in a lower incidence of major cardiovascular events at follow-up both in patients treated conservatively as well as in patients submitted to PCI (CURE and PCI-CURE trials). The early risk of myocardial necrosis before coronary revascularization was also reduced by clopidogrel in patients submitted to PCI, an effect already demonstrated with tirofiban and integrilin ("small molecules like" effect). A new therapeutic scheme including, at the time of admission, oral clopidogrel for platelet inhibition, an early risk assessment and the subsequent use of abciximab in the cath lab, if indicated is proposed for the treatment of unstable angina. The advantages associated with the proposed treatment have to be validated by ad hoc studies.

Integrated analysis of myocardial blush and ST-segment elevation recovery after successful primary angioplasty: Real-time grading of microvascular reperfusion and prediction of early and late recovery of left ventricular function

BACKGROUND

ST-segment elevation (SigmaSTe) recovery and the angiographic myocardial blush (MB) grade are useful markers of microvascular reperfusion after recanalization of the infarct-related artery. We investigated the ability of a combined analysis of MB grade and SigmaSTe changes to identify different patterns of myocardial reperfusion shortly after primary percutaneous coronary angioplasty (PTCA) and to predict 7-day and 6-month left ventricular (LV) functional recovery.

METHODS AND RESULTS

MB grade and SigmaSTe recovery were evaluated shortly after successful primary PTCA (restoration of TIMI grade 3 flow) in 114 consecutive patients with SigmaSTe acute myocardial infarction. LV function was assessed by 2D echocardiograms before PTCA and at 7 days and 6 months thereafter. By combining MB and SigmaSTe changes, 3 main groups of patients were identified. Group 1 patients (n=60) had both significant MB (grade 2 to 3) and SigmaSTe recovery (>50% versus basal SigmaSTe) and a high rate of 7-day (65%) and 6-month (95%) LV functional recovery. In group 2 patients (n=21), who showed MB but persistent SigmaSTe, the prevalence of early LV functional recovery was low (24%) but increased up to 86% in the late phase. Group 3 patients (n=28), who had neither significant MB nor SigmaSTe resolution, had poor early (18%) and late (32%) LV functional recovery.

CONCLUSIONS

After successful primary PTCA, integrated analysis of MB and SigmaSTe recovery allows a real-time grading of microvascular reperfusion of the infarct area and predicts the time-course and magnitude of LV functional recovery.

[Combination therapy for acute myocardial infarction with glycoprotein IIb/IIIa inhibitors and fibrinolysis]

Early achievement of TIMI 3 (normal) flow in the infarct-related artery is the goal of therapy of acute myocardial infarction (AMI) in order to reduce infarct size and improve clinical outcome. By the mid 1990s mechanical treatment (primary angioplasty) has been recognized as the best method to gain this goal but fibrinolysis still remains the standard of care because of logistic limitations of angioplasty. Benefit of aspirin in association with fibrinolytic drugs encouraged the use of antagonists of the glycoprotein IIb/IIIa receptor (abciximab, eptifibatide, tirofiban), which block the final common pathway of platelet aggregation in AMI therapy. In dose-finding and dose-confirmation studies the combination of a fibrinolytic agent with a glycoprotein IIb/IIIa receptor antagonist, such as abciximab, resulted in nearly 80% of patients achieving complete reperfusion at 90 min without a substantial increase in side effects. This combination was tested in the phase III GUSTO V study. Compared to full-dose reteplase alone, the association of half-dose of reteplase and abciximab significantly reduced most non-fatal complications of myocardial infarction such as reinfarction and need of urgent revascularization. Failure to show a reduction in mortality with "combo therapy" must be related to the low 30-day mortality observed in both arms of the study, the lowest ever found in fibrinolytic trials. Warning about an increase in non-intracranial bleeding is counterbalanced by similar rates of intracranial hemorrhages and non-fatal disabling strokes in the two groups. On the basis of the GUSTO V results it appears clear that future advances in the management of AMI will only be possible by combining different reperfusion modalities (lytics, IIb/IIIa antagonists and coronary angioplasty). Whichever is the best combination, mechanical reperfusion will play a central role in the management of AMI. A major challenge for cardiologists will be reinforcement of collaboration and synergy between institutions with different levels of resources.

Effect of Abciximab on prothrombin activation and thrombin generation in acute coronary syndromes without ST-segment elevation: Global Utilization of Strategies to Open Occluded Coronary Arteries Trial IV in Acute Coronary Syndromes (GUSTO IV ACS) Italian Hematologic Substudy

BACKGROUND

Abciximab is very effective in reducing major cardiac events in patients undergoing interventional procedures. Its antithrombotic effect is primarily attributable to the blocking of platelet glycoprotein IIb/IIIa receptors, but recent evidence suggests that it may have a direct antithrombin effect. No data are available concerning the effect of abciximab on the in vivo markers of prothrombin activation and thrombin generation in patients with acute coronary syndromes without ST elevation.

METHODS AND RESULTS

We measured the plasma levels of prothrombin fragment 1+2 (a marker of prothrombin activation) and the thrombin/antithrombin complex (a marker of thrombin generation) in 167 patients with acute coronary syndromes without ST elevation enrolled in the GUSTO IV ACS trial who were randomized to receive abciximab for 24 hours (52 patients), abciximab for 48 hours (59 patients), or placebo (56 patients) in addition to heparin. Blood samples were obtained at baseline (before any treatment), after 24 and 48 hours (before study drug discontinuation), and 1 month later. There was a significant increase in the plasma levels of prothrombin fragment 1+2 after 48 hours and after 1 month in all 3 groups, placebo (P=0.0001), 24-hour abciximab (P=0.0002), and 48-hour abciximab (P=0.0001). The plasma thrombin/antithrombin complex levels were similar in the 3 groups at all time points and did not change during the study drug infusions.

CONCLUSIONS

Abciximab does not decrease prothrombin activation and thrombin generation in patients with acute coronary syndromes without ST elevation not undergoing interventional procedures.

Thrombogenic potential of human coronary atherosclerotic plaques

Higher levels of tissue factor (the initiator of blood coagulation) have been found in coronary atherosclerotic plaques of patients with unstable coronary artery disease, but it is not established whether they are associated with a different thrombotic response to in vivo plaque rupture. In 40 patients undergoing directional coronary atherectomy, prothrombin fragment 1 + 2, a marker of thrombin generation, was measured in intracoronary blood samples obtained proximally and distally to the coronary atherosclerotic plaque before and after the procedure. Before the procedure, plasma prothrombin fragment 1 + 2 levels were significantly increased across the lesion in patients with unstable, but not in those with stable, coronary disease (unstable, median increase, 0.37 nM; range, -0.35-1.16 nM) (stable, median increase, -0.065 nM; range, -0.58-1.06 nM) (P =.0021). After plaque removal, an increase in prothrombin fragment 1 + 2 across the lesion was observed only in patients with unstable coronary disease (unstable, median increase, 0.25 nM; range, -1.04-4.9 nM) (stable, 0.01 nM; range, -0.48-3.59 nM) (P =.036)]. There was a correlation between the tissue factor content of the plaque and the increase in thrombin generation across the lesion (rho = 0.33; P =.038). The higher tissue factor content found in plaques obtained from patients with unstable coronary disease was associated with a local increase in thrombin generation, thus suggesting a link with the in vivo thrombogenicity of the plaque.

A 23bp insertion in the endothelial protein C receptor (EPCR) gene impairs EPCR function

EPCR is a type I transmembrane protein, highly expressed on the endothelium of large vessels, that binds protein C and augments its activation. In this study, a 23bp insertion in the EPCR gene was found in 4/198 survivors of myocardial infarction and 3/194 patients with deep vein thrombosis. The EPCR gene with the insertion predicts a protein that lacks part of the extracellular domain, the transmembrane domain and the cytoplasmic tail. Expression studies showed that the truncated protein is not localized on the cell surface, cannot be secreted in the culture medium, and does not bind activated protein C. Since protein C activation depends on the concentration of EPCR, patients with the EPCR insertion could have a diminished protein C activation capacity. Further clinical studies of adequate samples size are necessary to establish whether or not the EPCR insertion predisposes to the development of thrombotic events.

Tissue factor in human coronary atherosclerotic plaques

The rupture or fissuring of a coronary atherosclerotic plaque and subsequent thrombosis is considered the key event in the pathogenesis of unstable angina and myocardial infarction. Although plaque disruption frequently occurs during the evolution of atherosclerosis, only a minority of ruptured plaques develop thrombosis. The content and procoagulant activity of tissue factor in human coronary atherosclerotic plaques varies widely, and different studies confirm that it is higher in the plaques extracted from patients with unstable angina, myocardial infarction or histologic/angiographic evidence of coronary thrombosis than in those taken from patients with stable angina or uncomplicated coronary lesions. Variations in tissue factor content and activity may be responsible for the different thrombotic responses to human coronary atherosclerotic plaque rupture.

Prothrombotic genetic risk factors in young survivors of myocardial infarction

It has long been thought that an individual thrombotic tendency increases the risk of myocardial infarction, especially in young adults. Several "prothrombotic" genetic factors that may influence the individual thrombotic risk have been identified. To investigate the association between the risk of myocardial infarction at a young age and genetic factors thought to be associated with an increased tendency to thrombosis (the polymorphisms 4G/5G of the PAI-1 gene, PIA1/PIA2 of the platelet glycoprotein IIIa, C3550T of the platelet glycoprotein Ib gene, G10976A of the factor VII gene, C677T of the methylenetetrahydrofolate reductase gene, G1691A of the factor V gene, and G20210A of the prothrombin gene), we performed a case-control study evaluating 200 survivors (185 men, 15 women) of myocardial infarction who had experienced the event before the age of 45 years and 200 healthy subjects with a negative exercise test, individually matched for sex, age, and geographic origin with the cases. The presence of the PIA2 polymorphic allele was the only prothrombotic genetic factor associated with the risk of myocardial infarction at a young age. The odds ratio for carriers of the PIA2 allele compared with those of the PIA1 allele was 1.84 (95% confidence intervals (CI) 1.12 to 3.03). There was a significant interaction between the presence of the PIA2 allele and smoking: with their simultaneous presence, 46% (95% confidence intervals 11% to 81%) of premature myocardial infarctions were attributable to the interaction between the two factors. In conclusion, carrying the PIA2 polymorphic allele of platelet glycoprotein IIIa was the only genetic prothrombotic factor associated with the risk of developing myocardial infarction at a young age. The clinical expression of this genetic predisposition seems to be enhanced by smoking.

Comparison of dobutamine stress echocardiography and exercise stress Thallium-201 SPECT for detection of myocardial ischemia after acute myocardial infarction treated with thrombolysis

In order to compare the ability of dobutamine stress echocardiography (DSE) and exercise Thallium-201 SPECT to detect myocardial ischemia in patients with myocardial infarction (MI) treated with thrombolysis, 43 prospectively selected patients with MI treated with thrombolysis underwent within 1 month from MI DSE, stress-redistribution-reinjection Thallium-201 SPECT and coronary angiography. The echocardiographic and scintigraphic images were analyzed for the presence of myocardial ischemia using a 11-segment left ventricular model. DSE and exercise Thallium-201 SPECT detected myocardial ischemia in the infarct zone in 72% and 72% (31/43) of patients and ischemia at a distance in 12% (5/43) and 19% (8/43) of patients with a concordance of 67% and 88%, respectively. A significant agreement between DSE and exercise Thallium SPECT was found in the evaluation of the extent of both myocardial necrosis and stress-induced myocardial ischemia. DSE and exercise Thallium SPECT showed similar sensitivity (79 vs 76%), specificity (60 vs 60%) and accuracy (77 vs 74%) for detection of a critical stenosis of the infarct-related artery; there was also no significant difference between the tests in sensitivity, specificity and accuracy for detection of the multivessel disease. In conclusion, initially after thrombolyzed MI, DSE and exercise Thallium-201 SPECT detect myocardial ischemia in the infarct zone in a high proportion of patients and show a similar accuracy for the diagnosis of a critical stenosis of the infarct-related coronary artery and of the multivessel disease.

Dobutamine-induced ST-segment elevation in patients without myocardial infarction

During dobutamine stress echocardiography, ST-segment elevation developed in 20 of 372 patients (5%) without previous myocardial infarction and was associated with a transient severe asynergy of the myocardial region corresponding to the site of ST elevation. In 17 of 19 patients, ST-segment elevation was associated with a critical stenosis of the ischemia-related coronary artery, whereas in 2 of 19 patients with no critical lesions of the ischemia-related artery, coronary vasospasm was the most likely mechanism of myocardial ischemia.

Prognostic value of myocardial viability and ischemia detected by dobutamine stress echocardiography early after acute myocardial infarction treated with thrombolysis

OBJECTIVES

The aim of the study was to assess the prognostic value of myocardial viability and ischemia detected by dobutamine stress echocardiography (DSE) in patients with acute myocardial infarction (AMI) treated with thrombolysis.

BACKGROUND

DSE can detect myocardial viability and ischemia early after AMI, but the prognostic importance of viability and ischemia in these patients has yet to be assessed.

METHODS

DSE was performed in 152 patients at a mean of 9 +/- 5 days after a first AMI treated with thrombolysis to evaluate myocardial viability and ischemia. The patients were followed up for 15 +/- 19 months.

RESULTS

On the basis of DSE results three groups of patients were identified: group 1 (95 patients, 62.5%) with myocardial viability and ischemia, group 2 with myocardial viability without ischemia (32 patients, 21%) and group 3 (25 patients, 16.5%) with no myocardial viability. During follow-up 10 patients (6.5%) had hard events, 53 (35%) developed unstable angina and 67 (44%) underwent myocardial revascularization. The rate of hard events was 10% in group 1 and 0% in group 2 and 3 patients (p < 0.05 group 1 versus group 2); group 1 patients with viability and ischemia showed a significantly higher rate of recurrence of unstable angina and myocardial revascularization procedures (40% and 60%) compared to group 2 (22% and 16%) and group 3 patients (20% and 20%). Using the Cox multivariate stepwise model, only the extent of ischemic myocardium (hazard ratio (HR) = 21.7, p = 0.02) and angina during DSE (HR = 4.45, p = 0.03) were significant predictors of hard events; an ischemic response to DSE (HR = 2.92, p = 0.001) was the most important predictor of spontaneous events, followed by ST-segment depression during DSE (HR = 1.71, p = 0.04), angina during DSE (HR = 1.53, p = 0.19) and age (HR = 0.96, p = 0.05).

CONCLUSIONS

In patients with a first AMI treated with thrombolysis the presence and extent of myocardial ischemia during DSE is the most important predictor of both hard and spontaneous cardiac events, whereas myocardial viability does not have an independent prognostic value.

Significance of ST-segment elevation during dobutamine-stress echocardiography in patients with acute myocardial infarction treated with thrombolysis

BACKGROUND

Stress-induced ST-segment elevation in patients with recent myocardial infarction treated with thrombolysis has not been extensively investigated. According to the results of previous studies it may represent residual myocardial ischaemia or dyskinesia in the infarcted region. The aim of the study was to analyse the significance of dobutamine-induced ST-segment elevation in the infarcted area in a consecutive group of patients (n = 42, 41 men, mean age 53 +/- 7 years) with a first acute myocardial infarction treated with thrombolysis within 6 h from symptoms onset.

METHODS AND RESULTS

All patients underwent dobutamine-stress echocardiography (up to 40 micrograms.kg-1.min-1 + atropine) 7 +/- 3 days from the acute event and coronary arteriography within 1 month from the test. Significant ST-segment elevation was defined as a shift > or = 1 mm during dobutamine compared to baseline in at least two contiguous infarct-related leads; a correlation was made between the site of ST-segment elevation and wall motion changes during dobutamine. Dobutamine-induced ST-segment elevation in 23/42 (55%) patients (group 1) while no changes were observed in 19/23 (45%) patients (group 2). Compared to group 2, group 1 patients showed a higher asynergy score index (1.72 +/- 0.24 vs 1.50 +/- 0.32, P < 0.02) and a higher number of asynergic segments (5.04 +/- 1.9 vs 4.11 +/- 1.8), at baseline, a higher incidence of baseline and/or stress-induced dyskinesia (39 vs 10%, P < 0.05) in the infarct-related region and a higher percentage of occluded infarct-related arteries (48 vs 0%, P < 0.001). In the 42 patients studied, a significant correlation was found between baseline ST-segment elevation and baseline asynergy score index (RS = 0.56, P < 0.001) and between ST-segment elevation and asynergy score index at peak stress (RS = 0.55, P < 0.001). The incidence of reversible wall motion abnormalities indicative of myocardial viability and residual myocardial ischaemia was similar in the two groups (87 vs 84% and 74 vs 68%, respectively), while the number of segments with irreversible akinesia indicative of myocardial necrosis was higher in group 1 compared to group 2 (1.5 +/- 1.4 vs 0.9 +/- 1.4). Among the 23 patients of group 1 with dobutamine-induced ST-segment elevation, six had no reversible wall motion abnormalities indicative of myocardial ischaemia; of the 17 patients with myocardial ischaemia, 11 had > or = 50% and six had < or = 50% of basally asynergic segments showing reversible wall motion abnormalities.

CONCLUSIONS

In patients with recent thrombolyzed myocardial infarction dobutamine-induced ST-segment elevation is associated with a larger akinetic area in basal conditions and either with reversible wall motion abnormalities indicative of myocardial ischaemia or with irreversible or minimally reversible wall motion abnormalities in the infarct area during the test. Thus, dobutamine echocardiography provides useful information for the interpretation of stress-induced ST-segment elevation and clinical management of these patients.

Dobutamine stress echocardiography early after myocardial infarction treated with thrombolysis. Identification of myocardial viability and ischemia and relation to spontaneous functional recovery

The aim of the study was to assess the ability of dobutamine stress echocardiography to detect myocardial viability and ischemia in patients with acute myocardial infarction treated with thrombolysis and to correlate the acute response to dobutamine with late spontaneous functional recovery at follow-up. Forty-two consecutive patients with myocardial infarction treated with thrombolysis underwent low- (5 and 10 mcg/kg/min) and high-dose (20 to 40 mcg/kg/min) dobutamine stress echocardiography at a mean of 7 +/- 3 days of the acute phase. A follow-up 2D-echocardiogram was performed in all patients to evaluate the spontaneous recovery of function in the infarct area. On the basis of the response to the test, 3 groups of patients were identified: group 1 included 7 patients showing an improvement in left ventricular asynergy score index at low doses (from 1.5 +/- 0.3 to 1.3 +/- 0.2, p < 0.05) with no deterioration at high doses, indicative of myocardial viability without ischemia; group 2 (23 patients) showed a significant improvement in the asynergy index at low doses (from 1.58 +/- 0.3 to 1.32 +/- 0.32, p < 0.05) followed by a deterioration at high doses (1.68 +/- 0.4, p < 0.05 vs low-dose), suggestive of residual myocardial ischemia in the infarct zone; group 3 included 12 patients who showed no significant changes in the baseline asynergy score index (1.67 +/- 0.2) either at low or at high doses. The acute response to dobutamine stress echocardiography accurately predicted the spontaneous recovery of function in the infarct area at follow-up: both group 1 and group 2 patients showed a significant reduction in the asynergy score index (group 1: 1.16 +/- 0.3 vs 1.5 +/- 0.2, p < 0.001; group 2: 1.43 +/- 0.3 vs 1.58 +/- 0.3, p < 0.05), while group 3 had no recovery in the asynergy index (1.67 +/- 0.2 vs 1.67 +/- 0.2). Thus, in patients with acute myocardial infarction treated with thrombolysis dobutamine stress echocardiography can detect myocardial viability in 71% and ischemia in the infarct zone in 55% of patients; moreover, the response to the test during the acute phase is correlated with the degree of the late spontaneous recovery of function in the infarct area.

Thrombin activity and early outcome in unstable angina pectoris

BACKGROUND

The blood coagulation system is frequently activated in the acute phase of unstable angina, but it is unknown whether the augmented function of the hemostatic mechanism may serve as a marker of increased risk for an early unfavorable outcome.

METHODS AND RESULTS

Plasma concentrations and 24-hour urinary excretion of fibrinopeptide A were prospectively determined in 150 patients with unstable angina. All patients underwent 24-hour Holter monitoring, during which time urine was collected; at the end of this period, a blood sample was taken and coronary arteriography was performed. The patients were followed up for the occurrence of cardiac events (death and myocardial infarction) until they underwent coronary revascularization or until they were discharged from the hospital. Fibrinopeptide A plasma levels and 24-hour urinary excretion were found to be abnormally elevated in 50% and 45% of the study population, respectively. During hospitalization, 11 patients developed myocardial infarction and 2 patients died. Kaplan-Meier analysis demonstrated a significantly higher probability of developing cardiac events in patients with abnormal rather than normal plasma levels of fibrinopeptide A (P<.01), whereas no difference in outcome was observed between patients with normal and those with abnormal 24-hour urinary excretion. Cox regression analysis showed that the only variables independently related to an early unfavorable outcome were the presence of persistent ischemia during 24-hour Holter monitoring (P<.0001), the presence of intracoronary thrombosis at angiography (P=.016), and abnormal fibrinopeptide A plasma levels (P=.038).

CONCLUSIONS

Patients with unstable angina pectoris and abnormal fibrinopeptide A plasma levels are at increased risk for an early unfavorable outcome.

Comparison of dobutamine stress echocardiography with dipyridamole stress echocardiography for detection of viable myocardium after myocardial infarction treated with thrombolysis

OBJECTIVE

To compare the ability of dobutamine and dipyridamole stress echocardiography to detect functional recovery of stunned but viable myocardial regions early after acute myocardial infarction, and to predict late functional recovery of the reperfusion salvaged myocardium within the infarct area.

METHODS

Within 10 d of acute myocardial infarction, 51 patients--30 anterior and 21 inferior, 44 Q wave and seven non-Q-wave infarction--were submitted to a dobutamine echocardiography test at low dose (5-10 micrograms/kg/min over 5 min) and high dose (20-40 micrograms/kg/min over 3 min) and to dipyridamole echocardiography test (0.56 mg/kg over 4 min + 0.28 mg/kg over 2 min) on different days and in random order, after interruption of any vasoactive drug. Resting echocardiography was repeated at two months in 41 of 51 patients (80%). Regional wall motion of the left ventricle was analysed in a semiquantitative manner on a 14-segment model. Viability was defined as improvement of one grade or more of at least two basally asynergic segments in the infarcted area.

RESULTS

Regional functional recovery was detected by low dose dobutamine in 38/51 patients (75%) and in 147/308 (48%) of basally asynergic segments, compared to 25/51 patients (49%; P < 0.001) and 78/308 segments (25%; P < 0.001) only identified by dipyridamole. Late spontaneous functional recovery was detected in 24/41 patients (59%) and in 78/254 basally asynergic segments (31%). The sensitivity of dobutamine and dipyridamole echocardiography for predicting spontaneous functional recovery was 72% and 51% respectively (P < 0.001), specificity 68% and 82% (P < 0.001), positive predictive value 50% and 56%, and negative predictive value 85% and 79%.

CONCLUSIONS

In comparison with dipyridamole in patients with thrombolysed myocardial infarction, dobutamine induces regional functional recovery. This suggests that dobutamine is more sensitive in showing the presence of viable myocardium within the infarct zone, though it has a lower specificity in predicting delayed spontaneous functional recovery of non-contractile but still viable areas.

[Results and prognostic significance of echocardiography-dobutamine + atropine test in recent non-Q wave myocardial infarction]

BACKGROUND

Patients with non-Q wave myocardial infarction (NQ AMI) are usually considered to have an increased risk of recurrent ischemic events and reinfarction. We wished to assess whether dobutamine stress echocardiography with the addition of atropine (DOB-E + ATRO) can detect jeopardized myocardium after a recent NQ AMI and to assess the prognostic significance of this test in a group of patients with a first uncomplicated NQ AMI:

METHODS AND RESULTS

Fourty-one consecutive patients (38 men, mean age 52 +/- 9 years, 31 anterior, 68% treated with thrombolysis) underwent low and high-dose DOB-E (from 5 to 40 mcg/kg/min); ATRO was added in 14/41 (34%) patients. A significant deterioration of wall motion in the infarcted region (IR) indicative of residual myocardial ischemia was present in 36/41 patients (88%). Significant electrocardiographic changes and angina developed in 61% and 32% of patients, respectively. Coronary angiography was performed in 30/41 patients (73%) and showed 1-vessel coronary artery disease (CAD) in 70% of cases, multivessel CAD in 23% of cases and no significant CAD in 7% of patients. Three patients were lost at follow-up and 10 other patients were excluded from the analysis because a revascularization procedure was performed during diagnostic angiography. On a mean follow-up period of 9.5 +/- 9 months, the incidence of coronary events (re-infarction, recurrent angina, revascularization procedures) was higher (15/36 vs 1/5, 42% vs 20%) in patients with a DOB-E + ATRO positive test (1 reinfarction, 9 recurrent angina, 5 revascularized) than in those with a negative test (1 recurrent angina).

CONCLUSIONS

DOB-E + ATRO early after a first uncomplicated NQ AMI documents the presence of myocardial ischemia in the IR in the great majority of patients. A positive DOB-E + ATRO was found to be associated with a higher incidence of cardiac events at follow-up, but the results of this non prospective study (high sensitivity but low specificity and predictive value for cardiac events at follow-up) suggest to utilize with caution this test for risk stratification of patients with recent NQ AMI until prospective and larger studies are performed.

Results of dipyridamole plus atropine echo stress test for the diagnosis of coronary artery disease

Sensitivity of dipyridamole stress echocardiography (DIP-E) has been reported to be less than ideal in particular subsets of patients such as those with less severe extent of coronary artery disease (CAD). To verify if sensitivity could be improved, ATRO (1 mg in 2 minutes) was added at the end of a negative high-dose (0.84 mg/kg over 10 minutes) DIP-E in 61 consecutive patients (58 men, aged 53 +/- 7 years) evaluated for chest pain (33%) or for detection of residual ischemia after acute myocardial infarction (AMI) or previous MI (67%). DIP-E was positive in 28/61 (46%) and negative in 33/61 (54%) patients. Additional echo positivity was obtained in 18/33 (54%) patients after ATRO. Coronary arteriography was normal in 6 patients (10%); 1-vessel CAD was diagnosed in 28 (46%), 2-vessel CAD in 16 (26%) and 3-vessel CAD in 11 (18%) cases. The sensitivity for CAD diagnosis was 49% (27/55) for DIP-E and 84% (46/55) for DIP-E+ATRO (p < 0.001). Specificity was 83% and 80%, respectively. Diagnostic accuracy increased from 52% to 83% (p < 0.001). The better diagnostic accuracy of DIP-E was mainly related to the significant increase in sensitivity of the combined test in patients with 1-vessel CAD (from 46% to 75%) (p < 0.005). At quantitative coronary evaluation, compared to patients with positive DIP-E+ATRO or negative DIP-E+ATRO test, patients with positive DIP-E had a higher mean % diameter stenosis: 80 +/- 13% vs 72 +/- 24% and 65 +/- 36%, respectively. Peak heart rate was significantly higher after the addition of ATRO vs basal and DIP alone in patients with a positive DIP-E+ATRO test. The addition of ATRO to DIP increases diagnostic accuracy of DIP-E particularly in patients with less severe extent of CAD; ATRO may be considered as a useful routine procedure for increasing diagnostic value of DIP-E test.

[The side effects and safety of the echo-dobutamine test. The experience with 373 patients]

BACKGROUND

A potential limitation to the clinical utilization of dobutamine stress echocardiography is the higher incidence of side effects in respect to other noninvasive tests for the diagnosis of coronary artery disease reported by some authors. Due to the increased utilization of this test for the evaluation of chest pain and for prognostic stratification in patients with a recent myocardial infarction, we analyzed the results of 373 consecutive tests to evaluate the incidence and clinical significance of side effects induced by dobutamine.

METHODS

Dobutamine stress echocardiography was performed in 256 patients (69%) for the evaluation of chest pain; 85 out of 256 (33%) suffered from a previous myocardial infarction. 117 patients (31%) were studied in the early phase after an acute myocardial infarction for prognostic purposes. Dobutamine was infused starting with the dose of 5 gamma/kg/min over 3 minutes with incremental steps of 10-20-30-40 gamma/kg/min over 3 minutes under 2D-echocardiographic and 12-lead electrocardiographic monitoring.

RESULTS

In 95% of cases the test was stopped at the achievement of a target end point: wall motion abnormalities (60%), significant ECG changes (5%), 85% of the age-predicted maximal heart rate (13%), maximal dose (17%); only in 5% of cases a limiting side effect requiring a premature interruption of the test occurred: hypertension (systolic blood pressure over 240 mm Hg and/or diastolic over 120 mm Hg) (2%); symptomatic hypotension (0.5%); severe chest pain (1%); nausea (0.5%); cardiac arrhythmias (1%). Cardiac arrhythmias were the most frequently registered non limiting side effect. During the test 79 episodes of supraventricular arrhythmias and 211 episodes of ventricular arrhythmias occurred. Supraventricular arrhythmias consisted usually of benign sporadic premature beats; only 3 cases of self-limiting supraventricular tachycardia or atrial fibrillation were recorded. Sporadic ventricular premature beats were the most frequently recorded arrhythmias; 10 patients developed a ventricular tachycardia; however in no case this arrhythmia was sustained, associated with subjective symptoms and required the administration of a specific antiarrhythmic drug or the premature interruption of the test. Patients were divided according to the absence (Group 1, G1, n = 193, 52%) or the presence (Group 2, G2, n = 180, 48%) of cardiac arrhythmias during the test. Patients of G2 differed from patients of G1 only in respect of the maximal dose of dobutamine infused (33.5 vs 28.6 gamma/kg/min, p < 0.0005) and the incidence of a wall motion abnormality in the basal echocardiogram (66% vs 53%, p < .01). The second most recorded non limiting side effect (71/373 pts) (19%) was the occurrence of systolic hypotension, a drop of systolic blood pressure > or = 20 mm Hg in respect of the antecedent infusion step. In all cases no symptoms developed and the great majority of patients with this finding had a normal echocardiographic response to dobutamine at the time of his occurrence.

CONCLUSIONS

Dobutamine echo stress test is limited by the occurrence of significant side effects only in a minority of patients (5%); however in all cases, including complex ventricular arrhythmias, these side effects were self limiting and promptly recovered after interruption of the drug infusion. Non limiting side effects, in particular cardiac arrhythmias and systolic hypotension, are usually well tolerated and not associated with the occurrence of myocardial ischemia or left ventricular disfunction; thus, dobutamine echo stress test may be considered a safe test for the evaluation of the presence and severity of coronary artery disease both in patients with a previous or recent myocardial infarction and in patients without myocardial infarction.

[Adding atropine improves the diagnostic accuracy of dipyridamole-echo test]

BACKGROUND

The clinical experience with dipyridamole stress echocardiography for the diagnosis of coronary artery disease (CAD) revealed that patients with less severe extent of CAD and limited impairment of coronary reserve are frequently not recognized by the test. Increasing myocardial oxygen consumption adding atropine to dipyridamole may improve the diagnostic accuracy of dipyridamole for the detection of CAD.

METHODS

Fifty-two patients (48 men, aged 53 +/- 7 years) underwent a high-dose dipyridamole-echo stress test (0.84 mg/kg over 10 minutes) and coronary arteriography within 15 days from the test. Eighteen out of 52 patients were referred for chest pain; 11 suffered from a previous myocardial infarction (MI) and 23 were studied in the early phase after a first acute MI. Starting after 4 minutes from the end of dipyridamole infusion, atropine was added, in 2 doses of 0.5 mg each, at 1-minute interval in those patients with no echocardiographic evidence of myocardial ischemia after dipyridamole alone. Left ventricular wall motion was analyzed on a 11-segment left ventricular model in a qualitative manner.

RESULTS

Dipyridamole-echo stress test was positive in 23/52 (44%) and negative in 29/52 (56%) patients. In these patients atropine was added resulting in an additional echo positivity in 14/29 patients. Coronary arteriography was normal in 6 patients (12%); 1-vessel CAD was diagnosed in 23 (44%), 2-vessel CAD in 13 (25%) and 3-vessel CAD in 10 (19%) cases. The sensitivity for CAD diagnosis was 48% (22/46) for dipyridamole alone and 76% (35/46) for dipyridamole-atropine echo (p < .005), while the specificity was 83% (5/6) and 80% (4/5) respectively. Diagnostic accuracy increased from 52% (27/52) to 75% (39/52) (p < .001). The better diagnostic accuracy of dipyridamole-atropine echo stress test was mainly related to the increased sensitivity of the combined test in patients with 1-vessel CAD (from 39% to 70%) (p < .005). Peak heart rate was significantly higher after the addition of atropine (100 +/- 17 beats/min) compared to basal (64 +/- 10) and dipyridamole (85 +/- 12) in those patients with a positive dipyridamole-atropine echo stress test. No limiting side effects were elicited with the addition of atropine to dipyridamole.

CONCLUSIONS

The combination of atropine and dipyridamole induces a chronotropic stress adjunctive to flow maldistribution phenomena that permits to increase diagnostic accuracy of dipyridamole-echo stress test particularly in patients with less severe extent of CAD; it is usually well tolerated and safe and may be considered as a useful procedure for optimizing diagnostic value of dipyridamole-echo stress test.

Hemodynamics of volume loading compared with dobutamine in severe right ventricular infarction

To compare the hemodynamic effect of volume loading with that of dobutamine infusion in severe ischemic right ventricular (RV) dysfunction, 11 patients with inferior and RV infarction complicated by low cardiac output syndrome and important hemodynamic derangement (systolic blood pressure < 100 mm Hg, cardiac index < 2.0 liters/min/m2, right atrial pressure > 10 mm Hg) were prospectively studied within 48 hours of symptom onset. After right heart catheterization, volume loading (mean 400 ml saline solution) and dobutamine infusion (5 and 10 micrograms/kg/min over 10 minutes) were performed according to a randomized, crossover design. Volume loading resulted in increased right atrial (from 15 +/- 2 to 19 +/- 3 mm Hg, p < 0.05) and pulmonary capillary (from 15 +/- 2 to 19 +/- 3 mm Hg, p < 0.05) pressures, without increasing cardiac index, heart rate, aortic pressure, or right and left ventricular stroke work index. Dobutamine (5 micrograms/kg/min) increased cardiac index (from 1.5 +/- 0.3 to 1.9 +/- 0.5 liters/min/m2, p < 0.05), incrementing both heart rate (from 61 +/- 12 to 70 +/- 13 beats/min, p < 0.05) and stroke volume index (from 25 +/- 6 to 27 +/- 5 ml/beat/m2, p < 0.05), as well as right (from 1.4 +/- 1.6 to 2.3 +/- 2.2 g.m/m2, p < 0.05) and left (from 21 +/- 7 to 27 +/- 10 g.m/m2, p < 0.05) stroke work indexes; right and left ventricular filling pressures did not decrease. Dobutamine (10 micrograms/kg/min) significantly improved myocardial performance.(ABSTRACT TRUNCATED AT 250 WORDS)

Results of dobutamine stress echocardiography in patients with syndrome X

This study describes the results of Dobutamine stress echocardiography in 10 patients with Syndrome X. The diagnosis of Syndrome X was made on the basis of the presence of exertional angina, positive exercise stress test, negative ergonovine stress test and normal coronary arteries at angiography. All patients underwent Dobutamine stress echocardiography after interruption of any antianginal therapy. Dobutamine was infused starting with a dose of 5 mcg/kg/min over 3 minutes with incremental steps of 5 mcg/kg/min every 3 minutes up to a maximal dose of 40 mcg/kg/min. Two-dimensional echocardiography and 12-lead electrocardiography was monitored during the infusion of the drug. Nine patients received the maximal dose while one patient prematurely stopped the test for the occurrence of side effects. None of the ten patients developed segmental left ventricular wall motion abnormalities indicative of myocardial ischemia; ST-segment depression diagnostic for ischemia developed in 30% of patients; angina was elicited in one of these patients and in two additional patients. A hyperkinetic response to Dobutamine infusion involving all the segments of the left ventricle was observed both in patients with and without chest pain or electrocardiographic changes. In patients with Syndrome X Dobutamine induces a hyperkinetic left ventricular response indicative of normal contractile reserve despite the presence in some cases of angina and electrocardiographic signs of ischemia.

[The echo-dobutamine and echo-dipyridamole tests in assessing vital myocardium and residual ischemia in myocardial infarct after thrombolysis]

The aim of the study was to compare the ability of dobutamine and dipyridamole echocardiography to detect stunned but viable myocardium early after acute myocardial infarction, to predict spontaneous functional recovery of the reperfused myocardium at 2 months and to detect myocardial ischemia in the infarcted area. Within 10 days from acute myocardial infarction, 47 patients, 29 anterior and 18 inferior, 41 Q-wave and 6 non Q-wave infarctions, underwent dobutamine echocardiography test at low-dose (5-10 mcg/kg/min over 5 min) and high-dose (20-40 mgc/kg/min over 3 min) and to dipyridamole echocardiography test (0.56 mg/kg over 4 min + 0.28 mg/kg over 2 min) in different days and in random order, after interruption of any vasoactive drug. Resting echocardiography was repeated at 2 months in 38/47 patients. Regional wall motion analysis was performed in a qualitative manner on a 14-segment model; viability was defined as improvement of 1 grade or more of at least 2 basally asynergic segments in the infarcted area. Ischemia was defined as an improvement followed by significant deterioration of contractility of the infarcted segments or deterioration of the infarcted area. All patients underwent coronary arteriography within 1 month from admission. Viability was detected by low-dose dobutamine in 34/47 patients (72%) and in 131/297 (44%) of basally asynergic segments compared to only 21/47 patients (45%) and in 66/297 segments (22%) detected by dipyridamole; myocardial ischemia was induced by dobutamine in 64% of patients compared to 36% by dipyridamole. Late spontaneous functional recovery was detected in 21/38 patients (57%) and in 70/244 (29%) of asynergic segments. Sensitivity of dobutamine and dipyridamole echocardiography for predicting spontaneous functional recovery was 70% and 46% specificity 69% and 83%, positive predictive value 48% and 52%, negative predictive value 85% and 79% respectively. Dobutamine correctly identified the presence of a significant stenosis of the infarct-related artery in 74% of cases compared with 43% of dipyridamole; specificity for detecting stenosis was 67% for dobutamine and 83% for dipyridamole. In conclusion, in patients with thrombolyzed myocardial infarction dobutamine echocardiography detects viable myocardium with late spontaneous recovery in a greater proportion of patients and segments than dipyridamole; dobutamine has a higher sensitivity but a lower specificity compared to dipyridamole for identifying a residual stenosis of the infarct-related artery that may jeopardize myocardium in the area at risk.

[Echocardiography-dobutamine test in the short-term evaluation of the results of coronary angioplasty]

BACKGROUND

Coronary angioplasty is commonly performed as a means of coronary revascularization, but at present no method has proven to be of definite value in assessing the functional result of a given angiographic procedure.

OBJECTIVES

The purpose of this study was to evaluate whether dobutamine stress echocardiography can detect a reversal of ischemia-induced left ventricular regional wall motion abnormalities 15 days after an angiographically successful percutaneous transluminal coronary angioplasty (PTCA).

METHODS

25 patients underwent dobutamine stress echocardiography 24-48 hours before and 15 days after an elective angiographically successful PTCA. Twelve out of 25 patients (48%) suffered from a previous myocardial infarction. Symptomatic myocardial ischemia was documented before PTCA in 18/25 patients (72%) and asymptomatic ischemia in 7/25 (28%). Dobutamine was infused utilizing incremental steps of 5 mcg/kg/min over 3 minutes, up to a maximal dose of 40 mcg/kg/min. Echocardiographic images were stored on video tape and analyzed in a qualitative manner by two independent and experienced cardiologists without knowledge of the angiographic data. An asynergy score (from 0 = normal to 3 = dyskinesia) was calculated using a 14-segment left ventricular model in basal conditions and at peak stress, before and after PTCA. All tests were performed taking the patients off the antianginal therapy.

RESULTS

One-vessel coronary artery disease was present in 18/25 (72%) patients, and two-vessel disease in 7/25 (28%) four of these 7 patients underwent PTCA on both involved vessels; mean diameter of the stenosis was 91 +/- 6% before PTCA, and was reduced to 22 +/- 8% after PTCA. Dobutamine stress echocardiography induced wall motion abnormalities in 24/25 patients before and in 4/25 after PTCA; the frequency of dobutamine-induced wall motion abnormalities significantly decreased from 96% to 12% before and after angioplasty (p < .01). All patients developed regional wall motion abnormalities in the region supplied by the dilated vessel. Wall motion score at peak dobutamine infusion improved from 8.5 +/- 4.8 before PTCA to 2.6 +/- 4.9 after PTCA (p < .001). There was a significant increase in the rate-pressure product achieved during the test after PTCA (21300 +/- 400 bts/min.mmHg) compared to the test performed before PTCA (19000 +/- 500 bts/min.mmHg) (p < .05). Dobutamine induced angina in 6/25 patients (24%) and ST-segment changes in 19/25 patients (76%) before PTCA, whereas angina occurred only once after PTCA and ST-segment changes 6 times only after PTCA. No major side effects occurred during dobutamine infusion both before and after PTCA.

CONCLUSIONS

Our study indicates that dobutamine stress echocardiography is a feasible and safe method that accurately demonstrates an early improvement in stress-induced regional left ventricular dysfunction after an angiographically successful coronary angioplasty.

Dobutamine stress echocardiography for assessment of myocardial viability and ischemia in acute myocardial infarction treated with thrombolysis

To evaluate the role of dobutamine echocardiography for early assessment of myocardial viability and ischemia in acute myocardial infarction (MI), 59 patients with thrombolyzed acute MI underwent low- (5-10 micrograms/kg/min, 8 patients) and high-dose (20-40 micrograms/kg/min, 51 patients) dobutamine echocardiography at a mean of 8 +/- 4 days after acute MI. Myocardial viability in the infarct zone was documented in 43 of 59 (73%) patients (group 1), in whom mean asynergy score index decreased from 1.6 +/- 0.3 at baseline to 1.3 +/- 0.2 (p < 0.001), after low-dose dobutamine. No viability was present in 16 of 59 (27%) patients (group 2). At follow-up, recovery of regional contractile function was observed in group 1 (asynergy score index decreased from 1.6 +/- 0.3 to 1.4 +/- 0.3; p < 0.001), but not in group 2 patients. Sensitivity, specificity, and negative and positive predictive values of low-dose dobutamine echocardiography in predicting spontaneous recovery of function were 79%, 68%, 50%, and 89%, respectively. Of the 51 patients who underwent high-dose dobutamine, 26 of 36 (72%) group 1 patients showed a deterioration of contractility in the infarct zone indicative of myocardial ischemia compared with only 1 of 15 (7%) group 2 patients. At follow-up, recovery of regional function was greater in patients with no evidence of myocardial ischemia at high doses than in those with an ischemic response.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of dobutamine stress echocardiography, dipyridamole stress echocardiography and exercise stress testing for diagnosis of coronary artery disease

To compare the value of dobutamine and dipyridamole stress echocardiography with exercise stress testing for the diagnosis of coronary artery disease (CAD), 80 patients with chest pain of suspected myocardial ischemic origin (57 with CAD and 23 without significant CAD) underwent dobutamine stress echocardiography (5 to 40 micrograms/kg/min), dipyridamole echocardiography (0.84 mg/kg over 10 minutes) and bicycle exercise electrocardiography after discontinuation of antianginal treatment. Dobutamine echocardiography and exercise testing revealed a higher overall sensitivity than dipyridamole echocardiography (79 vs 60%, p < 0.005; 77 vs 60%, p < 0.05, respectively); this finding was due to a higher dobutamine and exercise sensitivity in 1-vessel CAD (62 vs 33%, p < 0.05 for both tests), whereas sensitivity of the 3 tests was similar in multivessel CAD. Dobutamine and dipyridamole showed a higher specificity than exercise (83 vs 43%, p < 0.01; 96 vs 43%, p < 0.005, respectively). Diagnostic accuracy of dobutamine echocardiography was higher than that of exercise (80 vs 67%, p < 0.05), whereas the difference with dipyridamole (80 vs 70%) was not significant. In the tests that yielded positive results, double product during exercise was significantly higher than that during dobutamine and dipyridamole echocardiography. No major complications occurred during the tests, but adverse effects were more frequent during dobutamine testing. Thus, dobutamine echocardiography may be superior to dipyridamole echocardiography and exercise electrocardiography for the diagnosis of CAD.

[Comparison of results of echo-dobutamine and ECG-dobutamine tests in the diagnosis of coronary disease]

The aim of the study was to compare the results of 2D-Echocardiographic (ECHO) vs 12-lead Electrocardiographic (ECG) monitoring during Dobutamine (DOB) infusion performed as a stress test in patients referred for the evaluation of chest pain of suspected ischemic origin. Fourty-seven consecutive patients, 40 m and 7 f, mean age 52 +/- 9 years, were studied after interruption of any antianginal therapy. DOB was infused in 5-minute stages with incremental doses of 5 mcg/kg/min up to a maximal dose of 40 mcg/kg/min. 2D-ECHO monitoring could not be performed in 3 out of 47 patients because of a poor acoustic window. Thus, the overall feasibility was 94% for 2D-ECHO DOB test vs 100% for ECG DOB test (p = ns). The ECG and 2D-ECHO findings were compared in the remaining 44 patients. Criteria for positivity were: transient regional dyssynergy absent or of lesser degree in the baseline examination for 2D-ECHO; ST-segment shift > 0.1 mV from baseline for ECG. The test was stopped when a regional wall motion abnormality developed even in the absence of significant ECG changes. Angiographically assessed coronary artery disease (CAD) was considered significant when a > 50% reduction of the luminal diameter in at least 1 major coronary vessel occurred. There were 10/44 patients with no significant CAD and 34/44 patients with CAD; 16 had single, 18 double or triple and/or left main vessel disease.(ABSTRACT TRUNCATED AT 250 WORDS)