Independent impact of thrombolytic therapy and vessel patency on left ventricular dilation after myocardial infarction. Serial echocardiographic follow-up

Major adverse cardiovascular events after implantation of absorb bioresorbable scaffold: One-year clinical outcomes

Background/Aim: Bioresorbable vascular scaffold (BVS) represents a novel generation of intracoronary devices designed to be fully resorbed after healing of the stented lesion, delivering antiproliferative drug to suppress restenosis, providing adequate diameter of the coronary vessel and preserving the vascular endothelial function. It was supposed that BVS will reduce neointimal proliferation and that their late bioresorption will reduce the negative effects of traditional drug-eluting stents, including the late stent thrombosis, local vessel wall inflammation, loss of coronary vasoreactivity and the need for the long-term dual antiplatelet therapy. The purpose of this research was to investigate efficacy and safety of Absorb everolimus-eluting BVS implantation and the prevalence of major adverse cardiovascular events (MACE) at the mid-term follow-up. Methods: The study encompassed 42 patients selected for BVS implantation and fulfilling inclusion criteria - 37 male and 5 female - admitted to the Dedinje Cardiovascular Institute, Belgrade, Serbia over the one-year period (from January 2015 to January 2016) for percutaneous coronary intervention (PCI). Coronary vessel patency before and after stenting was assessed by the Thrombolysis in Myocardial Infarction flow (TIMI) grades. After the index PCI procedure with BVS all patients were clinically followed by regular (prescheduled or event-driven) visits during the next 12-month period. Results: In the intention-to-treat analysis, all Absorb BVS procedures were successful, without the need for conversion to other treatment modalities. The complete reperfusion (TIMI flow grade 3) after the intervention was established in 97.6 % of patients and 100 % of them achieved the TIMI flow grade ≥ 2. The presence of angina pectoris was reduced significantly by the BVS procedure: stable angina 57.1 % to 11.9 %, (p < 0.001) and unstable angina 31 % to 0 %, respectively (p < 0.001). After the one-year follow-up, the MACE rate was 11.9 %. Myocardial infarction occurred in 4.8 % and the need for PCI reintervention in 2.4 % of cases (not influenced by the gender or the age of patients). There were 4 cases of death (all patients were older and had lower values of left ventricular ejection fraction). Conclusion: The results of the current research demonstrated a high interventional success rate of the Absorb BVS implantation, followed by the early improvement of the anginal status. However, that was not translated into the favourable mid-term clinical outcomes, opening debate about the current status of Absorb BVS and the need for future refinements of stent design and implantation techniques.

The Open Artery Hypothesis: Beneficial Effects and Long-term Prognostic Importance of Patency of the Infarct-Related Coronary Artery

There seem to be additional mechanisms of benefit in patients receiving late reperfusion therapy in a time when the opportunity for myocardial salvage has been missed. Previous studies have demonstrated that the restoration of blood flow in the infarct-related coronary artery in patients with acute myocardial infarction improves left ventricular function and reduces mortality. Initially, it was thought that survival was improved because viable myocardium was salvaged. However, data obtained over the past several years have suggested that the restoration of antegrade flow in the infarct-related artery may improve survival via a mechanism independent of the influence on left ventricular function. Clinical interest in the open artery hypothesis has recently resurfaced owing to a substantial improvement in technical aspects of percutaneous coronary interventions (PCI). Observational data suggest a role for late intervention as safer and more effective mechanical reperfusion practices have emerged. Long-term clinical benefits have been shown from balloon angioplasty late after myocardial infarction (MI). Therefore, patients with failed thrombolysis or those with late-presenting MI may still benefit from PCI by mechanisms independent of myocardial salvage. There is accumulative evidence on this matter. Possible mechanisms include reduction of ventricular remodeling, diminished ventricular instability reducing the incidence of arrhythmias, and provision of collaterals to other territories in the event of further coronary artery occlusion. However, caution must be exercised in interpreting the results of studies examining the open artery hypothesis. This hypothesis can be tested in its purest sense in animal experiments; however, the clinical situation is much more complex. Patients may have acute-on-chronic coronary artery occlusion in the presence of multivessel disease and well-developed collateral channels. The pattern of necrosis may also be different with areas of necrosis separated by islands of ischemic, stunned, hibernating, or normal cells. Therefore, the patency of the infarct-related coronary artery in single or multivessel disease days to weeks after infarction markedly influences long-term prognosis unrelated to improvement of left ventricular function. Current technology has made it feasible to open and maintain patency of most occluded infarct-related arteries. However, the hypothesis that late mechanical reperfusion in patients with asymptomatic occluded infarct-related artery will improve long-term clinical outcomes remains to be proved and is currently being tested in a large randomized trial.

Early short-term doxycycline therapy in patients with acute myocardial infarction and left ventricular dysfunction to prevent the ominous progression to adverse remodelling: the TIPTOP trial

AIMS

Experimental studies suggest that doxycycline attenuates post-infarction remodelling and exerts protective effects on myocardial ischaemia/reperfusion injury. However, the effects of the drug in the clinical setting are unknown. The aim of this study was to examine the effect of doxycycline on left ventricular (LV) remodelling in patients with acute ST-segment elevation myocardial infarction (STEMI) and LV dysfunction.

METHODS AND RESULTS

Open-label, randomized, phase II trial. Immediately after primary percutaneous coronary intervention, patients with STEMI and LV ejection fraction < 40% were randomly assigned to doxycycline (100 mg b.i.d. for 7 days) in addition to standard therapy, or to standard care. The echo LV end-diastolic volumes index (LVEDVi) was determined at baseline and 6 months. (99m)Tc-Sestamibi-single-photon emission computed tomography infarct size and severity were assessed at 6 months. We calculated a sample size of 110 patients, assuming that doxycycline may reduce the increase in the LVEDVi from baseline to 6 months > 50% compared with the standard therapy (statistical power > 80% with a type I error = 0.05). The 6-month changes in %LVEDVi were significant smaller in the doxycycline group than in the control group [0.4% (IQR: -16.0 to 14.2%) vs.13.4% (IQR: -7.9 to 29.3%); P = 0.012], as well as infarct size [5.5% (IQR: 0 to 18.8%) vs. 10.4% (IQR: 0.3 to 29.9%) P = 0.052], and infarct severity [0.53 (IQR: 0.43-0.62) vs. 0.44 (IQR: 0.29-0.60), P = 0.014], respectively.

CONCLUSION

In patients with acute STEMI and LV dysfunction, doxycycline reduces the adverse LV remodelling for comparable definite myocardial infarct size (NCT00469261).

Cardiac imaging after myocardial infarction

After myocardial infarction, optimal clinical management depends critically on cardiac imaging. Remodelling and heart failure, presence of inducible ischaemia, presence of dysfunctional viable myocardium, future risk of adverse events including risk of ventricular arrhythmias, need for anticoagulation, and other questions should be addressed by cardiac imaging. Strengths and weaknesses, recent developments, choice, and timing of the different non-invasive techniques are reviewed for this frequent clinical scenario.

Early mitral regurgitation after acute myocardial infarction does not contribute to subsequent left ventricular remodeling

BACKGROUND

It is well known that mitral regurgitation may lead to left ventricular dilation; however, the relationship between progressive left ventricular dilation after acute myocardial infarction (MI) and mitral regurgitation has not yet been clarified.

HYPOTHESIS

This study tested the hypothesis that early mitral regurgitation contributes to left ventricular remodeling after acute MI.

METHODS

We prospectively evaluated 131 consecutive patients by serial two-dimensional and Doppler echocardiography on Days 1, 2, 3, and 7, after 3 and 6 weeks, 3 and 6 months, and 1 year following acute MI. Patients were divided into two groups: those with mitral regurgitation in the first week after acute MI (Group 1, n = 34) and those without mitral regurgitation (Group 2, n = 81).

RESULTS

Over 1 year, a significant increase in end-diastolic volume index (from 62.1 +/- 12.9 to 70.5 +/- 23.6 ml/m2, p = 0.001) with a strong linear trend (F = 15.1, p < 0.001) was noted. Initial end-diastolic volume index was higher in Group 1 (65.6 +/- 13.3 vs. 60.4 +/- 12.5 ml/m2, p = 0.047), but this difference remained constant throughout the study (F = 1.76, p = NS). Therefore, the pattern of end-diastolic volume changes was similar in both groups during the period of observation.

CONCLUSIONS

These data indicate that early mitral regurgitation after acute MI does not contribute to subsequent left ventricular remodeling in the first year after myocardial infarction.

Preinfarction angina prevents left ventricular remodeling in patients treated with thrombolysis for myocardial infarction

BACKGROUND

It has been shown that preinfarction angina may have beneficial effects on infarct size and mortality. However, there are no studies that have serially assessed the impact of preinfarction angina on left ventricular (LV) function in a large series of patients.

HYPOTHESIS

The study was undertaken to determine whether preinfarction angina (within 7 days before infarction) influences LV remodeling.

METHODS

In all, 119 consecutive patients with acute myocardial infarction were serially evaluated by 2-dimensional echocardiography (on Days 1, 2, 3, and 7; at 3 and 6 weeks; and at 3, 6, and 12 months following infarction). Left ventricular volumes were determined using Simpson's biplane formula and normalized for body surface area. Wall motion score index and sphericity index were calculated for each study. Coronary angiography was performed before discharge.

RESULTS

Preinfarction angina was detected in 39 of 119 patients. Initial echocardiographic and clinical data as well as the incidence of patent infarct-related artery and collaterals were similar for patients with and without preinfarction angina. In the subset of thrombolysed patients, patients with preinfarction angina showed decrease of LV end-diastolic and end-systolic volumes during the follow-up period (p = 0.033 and p = 0.001, respectively), and improvement of wall motion score index (p < 0.001) and ejection fraction occurred (p = 0.001), without changing of LV shape (p > 0.05); in addition, patients with preinfarction angina had smaller LV volumes and higher ejection fraction than did those without angina, from 3 weeks onward. These favorable effects were not detected in patients not treated with thrombolysis.

CONCLUSIONS

These data indicate that preinfarction angina has an inhibiting effect on long-term LV remodeling in patients who underwent thrombolysis for first acute myocardial infarction. It appears that preinfarction angina has no impact on infarct size and early postinfarction LV function.

Detection of significant residual stenosis of the infarct-related artery after thrombolysis by high-dose dipyridamole echocardiography test: is it detected often enough?

BACKGROUND AND HYPOTHESIS

It has been reported that high-dose dipyridamole echocardiography test (DET) can be successfully used for the detection of critical residual stenosis of the infarct-related artery (IRA). However, we have recently noticed low sensitivity of DET for the detection of residual IRA stenosis in patients with single-vessel disease. This study sought to determine the value of DET for the detection of significant residual stenosis of the IRA after thrombolysis.

METHODS

Dipyridamole echocardiography test was performed in 55 consecutive patients after a first acute myocardial infarction before hospital discharge. All patients underwent coronary angiography 23 +/- 6 days after infarction.

RESULTS

Nine of 19 patients with positive DET revealed new adjacent asynergy and all of the patients had patient and significantly stenotic IRA. Sensitivity and specificity of DET in identifying significant residual stenosis of the IRA were 24 and 100%, respectively. Among 49 patients with significantly stenotic of occluded IRA, 40 patients without adjacent asynergy during DET had higher baseline wall motion score index (WMSI) compared with 9 patients who revealed adjacent asynergy during DET (1.45 +/- 0.30 vs. 1.24 +/- 0.18; p < 0.05). When all patients with positive DET (adjacent or remote asynergy) were compared with those with negative DET, no difference in baseline WMSI was found (1.37 +/- 0.24 vs. 1.44 +/- 0.24; p > 0.05).

CONCLUSIONS

Our data indicate that sensitivity of DET in detecting significant residual stenosis of the IRA after thrombolysis is low. It seems that the extent of myocardial infarction affects the ability of DET to detect adjacent, but not remote asynergy.

Emergent angioplasty prevents left ventricular dilation in patients with acute anterior wall myocardial infarction and cardiogenic shock

BACKGROUND

Percutaneous transluminal coronary angioplasty (PTCA) reduces in-hospital mortality and improves long-term outcome in patients with acute myocardial infarction (MI) complicated by cardiogenic shock. However, no study has evaluated the effects of different reperfusion therapies on left ventricular (LV) dimension and cardiac function in long-term survivors of MI with cardiogenic shock.

HYPOTHESIS

We investigated the effects of PTCA on the development of LV dilation in patients who survived MI complicated by cardiogenic shock.

METHODS

We studied 34 patients with a first MI and cardiogenic shock in whom two-dimensional echocardiography was performed immediately after admission and 1 month after infarction. Group A consisted of 17 patients who underwent emergent PTCA during the acute phase of MI, and Group B consisted of 17 patients who did not undergo PTCA. We also studied 119 patients with a first uncomplicated acute anterior MI, including 53 who underwent PTCA (Group C) and 66 who did not (Group D). The length and wall thickness of the infarcted and noninfarcted endocardial segments were determined immediately after MI and 1 month later, and LV ejection fraction (LVEF) was measured during the chronic phase.

RESULTS

The lengths of the infarcted and noninfarcted endocardial segments were significantly greater in Group B than in the other three groups (p < 0.05). The LVEF was significantly lower in Group B than in the other three groups (p < 0.05).

CONCLUSIONS

We conclude that PTCA performed in patients during the acute phase of MI complicated by cardiogenic shock lowers in-hospital mortality and prevents both LV dilation and a decrease in LVEF.

Predictors of early and late ventricular remodeling after acute myocardial infarction

BACKGROUND

The determinants of the early and late stages of the ventricular remodeling process after infarction are not well defined.

HYPOTHESIS

The study was undertaken to evaluate the factors that condition the time course of left ventricular dilation during the first 6 months after infarction.

METHODS

The study group consisted of 74 patients with a first intermediate-large (> or = 4 Q waves) acute myocardial infarction. Contrast left ventricular and coronary angiograms were performed at 7 +/- 1 and 175 +/- 25 days after infarction. Left ventricular volumes, regional function and infarction artery status were quantified. Percutaneous transluminal coronary angioplasty (PTCA) was performed in the early angiogram in 31 patients.

RESULTS

In the early angiogram, 13 patients showed ventricular remodeling (end-diastolic volume > 90 ml/m2). A larger extent of dysfunction was the only predictor (p < 0.002) of early remodeling. At 6 months, a smaller, early end-diastolic volume (p < 0.0001) and a poorer regional function recovery (p < 0.05) were independently related to late diastolic enlargement, and a poorer regional function recovery (p < 0.0001) and a smaller, early end-systolic volume (p < 0.009) were independently related to late systolic enlargement. One patient with compared with 20 patients without early remodeling (p < 0.04) presented with late remodeling (increment of the end-diastolic volume > 20% at 6 months). In patients with early remodeling, the end-diastolic volume did not change significantly (101 +/- 13 vs. 94 +/- 22 ml/m2, NS) at 6 months; despite this, they maintained larger diastolic volumes than patients with late remodeling (81 +/- 12 ml/m2, p < 0.04) at 6 months. Infarction artery status did not influence the evolution of ventricular volumes and regional function.

CONCLUSIONS

(1) A large infarct size is the main determinant of postinfarction remodeling. (2) Such infarct size-dependent ventricular dilation occurs early and does not tend to increase in late stage; in contrast, some cases of intermediate-large size infarcts without early remodeling exhibit late remodeling associated with a poor late recovery of regional function. (3) Recovery of regional function (indicating myocardial viability) rather than infarction artery status plays a role in the late ventricular remodeling process.

Early Prediction of Infarct Size by Strain Doppler Echocardiography After Coronary Reperfusion

OBJECTIVES

The objective of this study was to investigate whether strain Doppler echocardiography performed immediately after revascularization by percutaneous coronary intervention could predict the extent of myocardial scar, determined by contrast-enhanced magnetic resonance imaging (MRI).

BACKGROUND

There is considerable variability in survival rate after percutaneous coronary intervention, and accurate early risk stratification is therefore of major clinical importance.

METHODS

Thirty individuals with acute anterior myocardial infarction were examined with longitudinal strain by Doppler 1.5 h after revascularization. The extent of scarring 9 months later was analyzed by MRI in 16 corresponding myocardial segments. Strain in all left ventricular segments was averaged to obtain a global value. Infarct size was estimated by clinical parameters and cardiac markers.

RESULTS

A good correlation was found between the global strain and total infarct size (R = 0.77, p < 0.00001). A multivariate regression analysis showed that global peak strain and serum glutamic oxaloacetic transaminase correlated with the infarct size measured by MRI (p = 0.0001 and p = 0.001, respectively). Furthermore, a clear inverse relationship was found between the segmental strain and the transmural extent of infarction in each segment (R = 0.67, p < 0.0001).

CONCLUSIONS

This study demonstrates that assessment of regional and global strain at 1.5 h after reperfusion therapy correlates with size and transmural extent of myocardial infarction as determined by contrast-enhanced MRI. The novel global strain parameter is a valuable predictor of the total extent of myocardial infarction and may therefore be an important clinical tool for risk stratification in the acute phase of myocardial infarction.

[Acute coronary syndrome in the prehospital phase]

Cardiovascular diseases are the number one cause of death in Germany. In 2002 about 70,000 people died of acute myocardial infarction (AMI) and of these 37% died before arrival at hospital which underlines the relevance of adequate prehospital care. The generic term acute coronary syndrome (ACS) was introduced because a single pathomechanism accounts for the different forms and comprises unstable angina pectoris (iAP), non-ST-elevation myocardial infarction (NSTEMI), ST-elevation myocardial infarction (STEMI) and sudden cardiac death (SCD). Characteristic features are retrosternal pain, vegetative symptoms and radiation of pain into the adjoining regions. Further differentiation can only be achieved by the 12-lead ECG, as cardiac-specific enzymes do not play a role in prehospital decisions. Prehospital delays should be avoided, history and physical examination should be brief but focused, vital parameters should be assessed and monitored. Basic treatment for ACS should comprise inhalative oxygen, nitrates, morphine, aspirin and beta-blockers. If STEMI is diagnosed, patients with symptoms <12 h should undergo fibrinolytic therapy unless there is primary percutaneous coronary intervention (PCI) available within 90 min or if contraindicated. Heparin should be given to patients with STEMI depending on the choice of fibrinolytic agent, it otherwise results in a higher risk of bleeding, but in patients with iAP or NSTEMI it reduces mortality. All patients must be accompanied by the emergency physician during transportation and should be brought to a hospital with primary PCI, especially those with complicated ACS. Treatment of complications depends largely on the type, persistence and severity.

Adjunctive effect of hyperbaric oxygen treatment after thrombolysis on left ventricular function in patients with acute myocardial infarction

BACKGROUND

The role of hyperbaric oxygen in patients with acute myocardial infarction is controversial, ranging from not beneficial to having a favorable effect. This randomized study was conducted to further assess the benefit of hyperbaric oxygen treatment after thrombolysis on left ventricular function and remodeling in patients with acute myocardial infarction.

METHODS

Seventy-four consecutive patients with first acute myocardial infarction were randomly assigned to treatment with hyperbaric oxygen treatment combined with streptokinase (HBO+) or streptokinase alone (HBO-).

RESULTS

There was a significant decrease of end-systolic volume index from the first day to the third week in HBO+ patients compared with HBO- patients (from 30.40 to 28.18 vs from 30.89 to 36.68 mL/m2, P <.05) accompanied with no changes of end-diastolic volume index in HBO+ compared with increased values in HBO- (from 55.68 to 55.10 vs from 55.87 to 63.82 mL/m2, P <.05). Ejection fraction significantly improved in the HBO+ group and decreased in the HBO- group of patients after 3 weeks of acute myocardial infarction (from 46.27% to 50.81% vs from 45.54% to 44.05 %, P <.05).

CONCLUSIONS

Adjunctive hyperbaric oxygen therapy after thrombolysis in acute myocardial infarction has a favorable effect on left ventricular systolic function and the remodeling process.

Value of myocardial contrast echocardiography for predicting left ventricular remodeling and segmental functional recovery after anterior wall acute myocardial infarction

OBJECTIVE

We sought to study the value of microvascular perfusion assessed by myocardial contrast echocardiography in predicting left ventricular remodeling after anterior wall acute myocardial infarction.

METHODS

In 31 patients myocardial contrast echocardiography was performed up to 48 hours after acute myocardial infarction with determination of end-diastolic and end-systolic volumes, wall-motion score index, and myocardial perfusion score index (MPSI) at rest and under dobutamine stress at 6 months. Patients were classified into remodeling group (RG) (n = 19) and non-RG (n = 12), and, according to number of segments without opacification, reflow (< or =2 segments, n = 15) and no-reflow (>2 segments, n = 16) groups.

RESULTS

Wall-motion score index (1.84 +/- 0.22 vs 1.64 +/- 0.3; P =.049), MPSI (1.53 +/- 0.25 vs 1.26 +/- 0.17; P =.006), and number of segments without contrast (3.11 +/- 2.23 vs 1.08 +/- 1.38; P =.018) were higher in RG than in non-RG. End-diastolic and end-systolic volumes, and wall-motion score index, increased significantly in RG at 6 months and decreased in non-RG. MPSI increased in RG (1.53 +/- 0.25-1.66 +/- 0.21; P =.011) and was the only independent predictor of left ventricular remodeling (odds ratio = 1.8; 95% confidence interval = 1.15-2.82; P =.010). No-reflow group presented 27.8 +/- 19.9% of segments with resting functional recovery or contractile reserve, and reflow group presented 69.9 +/- 31.2% (P <.001).

CONCLUSION

MPSI obtained 48 hours after acute myocardial infarction is an independent predictor of left ventricular remodeling. Patients with two or fewer segments without opacification revealed a better prognosis of resting ventricular function and contractile reserve.

The trans-cardiac conductance method for on-line measurement of left ventricular volume: assessment of parallel conductance offset volume

The trans-cardiac conductance (TCC) method provides on-line left ventricular (LV) volume signals by determining the electrical conductance of blood in the LV by means of central venous and epithoracic electrodes. Conductive structures outside the LV blood pool cause a "parallel conductance" offset term (Vp) that can be determined by bolus injections of hypertonic saline in the pulmonary artery (Vp(saline)), which cause a transient increase in blood conductivity. This study in anesthetized sheep evaluates the accuracy of the saline calibration method and the variabilities of Vp between animals, between hemodynamic conditions and during the cardiac cycle. The conventional intra-cardiac conductance catheter method was used to obtain independent estimates of Vp by the zero-volume method (Vp(zero volume)). Mean baseline Vp(saline) and Vp(zerovolume) were 104 +/- 6 ml and 106 +/- 6 ml, respectively. Bland-Altman analysis showed a small nonsignificant bias (-2.5 ml) and narrow limits of agreement (4.6 ml). Vp was not significantly different between hemodynamic conditions (baseline, dobutamine, volume load, propranolol), but had a substantial interanimal variability (IAV) (38%). Average variations during the cardiac cycle were < 10% of mean Vp. We conclude that the saline method can be applied to determine Vp for TCC. IAV is substantial, so that Vp must be determined in each animal, but within-animal variability is relatively small.

Late intervention after anterior myocardial infarction: effects on left ventricular size, function, quality of life, and exercise tolerance: results of the Open Artery Trial (TOAT Study)

OBJECTIVE

We sought to conduct a randomized trial comparing late revascularization with conservative therapy in symptom-free patients after acute myocardial infarction (AMI).

BACKGROUND

In the absence of ischemia, the benefits of reperfusion late after AMI remain controversial. However, the possibility exists that an open infarct related artery benefits healing post AMI.

METHODS

Of 223 patients enrolled with Q-wave anterior AMI, 66 with isolated persistent occlusion of the left anterior descending coronary artery (LAD) were randomized to the following treatments: 1) medical therapy (closed artery group; n = 34) or 2) late intervention and stent to the LAD + medical therapy (open artery group; n = 32). The study was powered to compare left ventricular (LV) end-systolic volume between the two groups 12 months post AMI.

RESULTS

Late intervention 26 +/- 18 days post AMI resulted in significantly greater LV end-systolic and end-diastolic volumes at 12 months than medical therapy alone (106.6 +/- 37.5 ml vs. 79.7 +/- 34.4 ml, p < 0.01 and 162.0 +/- 51.4 ml vs. 130.1 +/- 46.1 ml, p < 0.01, respectively). Exercise duration and peak workload significantly increased in both groups from 6 weeks to 12 months post AMI, although absolute values were greater in the open artery group. Quality of life scores tended to deteriorate during this time interval in the closed artery patients but remained unchanged in the open artery patients. Coronary angiography at 1 year documented a low incidence of intergroup cross-over (spontaneous recanalization in 19% and closure in 11%).

CONCLUSIONS

In the present study, recanalization of occluded infarct-related arteries in symptom-free patients approximately 1 month post AMI had an adverse effect on remodeling but tended to increase exercise tolerance and improve quality of life.

Safety of coronary stenting early after thrombolysis in patients with acute myocardial infarction: one- and six-month clinical and angiographic evolution

To determine the feasibility and safety of early posthrombolysis coronary stenting and the incidence of further reocclusion, we followed 99 consecutive patients with acute myocardial infarction thrombolyzed with rt-PA 2.0 +/- 0.8 hr after onset. Culprit artery was stented 14.0 +/- 7.0 hr after thrombolysis. All patients underwent clinical and angiographic follow-up at 1 and 6 months. Angiographic success was achieved in 99% of cases. Neither major cardiac events nor bleeding or vascular complications occurred during hospital stay. At 30 days, no events occurred and normal flow persisted in all stented arteries. At 6 months, only one artery reoccluded (1%), resulting in a nonfatal reinfarction. Restenosis rate was 21%. Contribution of the infarcted area to left ventricular function significantly increased from baseline to 30-day and to 6-month evaluations. Thus, early posthrombolysis stenting is a safe strategy with a low reocclusion rate, which seems to allow functional recovery of the infarcted area. Further studies are necessary to define its impact on survival and cost-effectiveness.

Prognostic value of left ventricular diastolic function and association with heart rate variability after a first acute myocardial infarction

OBJECTIVE

To study the prognostic value of left ventricular (LV) diastolic function and its relation with autonomic balance expressed by heart rate variability (HRV) in patients after a first acute myocardial infarction.

DESIGN

The study population consisted of 64 consecutive patients with first acute myocardial infarction and 31 control subjects. Long and short term HRV indices were evaluated by 24 hour Holter monitoring, and LV systolic and diastolic function were assessed by two dimensional and Doppler echocardiography before discharge. Patients were divided into two groups: those with restrictive LV filling characteristics (deceleration time </= 140 ms) and those with non-restrictive LV filling characteristics (deceleration time > 140 ms).

RESULTS

Both long and short term HRV indices were significantly reduced in patients with restrictive LV filling compared with the non-restrictive group and control subjects. Mitral deceleration time and isovolumetric relaxation time correlated weakly but significantly with all indices of HRV whereas ejection fraction correlated weakly with the long term HRV indices. The mean follow up time was 14.9 (8.7) months. Multivariate analysis showed that mitral deceleration time (chi(2) = 6.4, p < 0.001) and ejection fraction </= 40% (chi(2) = 4.4, p < 0.05) were independent predictors of cardiac death and readmission to hospital with congestive heart failure.

CONCLUSIONS

A restrictive LV filling pattern was found to be the strongest predictor of adverse outcome independent of HRV and ejection fraction during follow up after a first acute myocardial infarction. Patients with restrictive LV filling characteristics had more reduced HRV than those with non-restrictive diastolic filling.

Short early filling deceleration time on day 1 after acute myocardial infarction is associated with short and long term left ventricular remodelling

OBJECTIVE

To assess the relations between early filling deceleration time, left ventricular remodelling, and cardiac mortality in an unselected group of postinfarction patients.

DESIGN AND PATIENTS

Prospective evaluation of 131 consecutive patients with first acute myocardial infarction. Echocardiography was performed on day 1, day 2, day 3, day 7, at three and six weeks, and at three, six, and 12 months after infarction. According to deceleration time on day 1, patients were divided into groups with short (< 150 ms) and normal deceleration time (⩾ 150 ms).

SETTING

Tertiary care centre.

RESULTS

Patients with a short deceleration time had higher end systolic and end diastolic volume indices and a higher wall motion score index, but a lower ejection fraction, in the year after infarction. These patients also showed a significant increase in end diastolic (p < 0.001) and end systolic volume indices (p = 0.007) during the follow up period, while ejection fraction and wall motion score index remained unchanged. In the group with normal deceleration time, end diastolic volume index increased (p < 0.001) but end systolic volume index did not change; in addition, the ejection fraction increased (p = 0.002) and the wall motion score index decreased (p < 0.001). One year and five year survival analysis showed greater cardiac mortality in patients with a short deceleration time (p = 0.04 and p = 0.02, respectively). In a Cox model, which included initial ejection fraction, infarct location, and infarct size, deceleration time on day 1 was the only significant predictor of five year mortality.

CONCLUSIONS

A short deceleration time on day 1 after acute myocardial infarction can identify patients who are likely to undergo left ventricular remodelling in the following year. These patients have a higher one year and five year cardiac mortality.

Short early filling deceleration time on day 1 after acute myocardial infarction is associated with short and long term left ventricular remodelling

OBJECTIVE

To assess the relations between early filling deceleration time, left ventricular remodelling, and cardiac mortality in an unselected group of postinfarction patients.

DESIGN AND PATIENTS

Prospective evaluation of 131 consecutive patients with first acute myocardial infarction. Echocardiography was performed on day 1, day 2, day 3, day 7, at three and six weeks, and at three, six, and 12 months after infarction. According to deceleration time on day 1, patients were divided into groups with short (< 150 ms) and normal deceleration time (>/= 150 ms).

SETTING

Tertiary care centre.

RESULTS

Patients with a short deceleration time had higher end systolic and end diastolic volume indices and a higher wall motion score index, but a lower ejection fraction, in the year after infarction. These patients also showed a significant increase in end diastolic (p < 0.001) and end systolic volume indices (p = 0.007) during the follow up period, while ejection fraction and wall motion score index remained unchanged. In the group with normal deceleration time, end diastolic volume index increased (p < 0.001) but end systolic volume index did not change; in addition, the ejection fraction increased (p = 0.002) and the wall motion score index decreased (p < 0.001). One year and five year survival analysis showed greater cardiac mortality in patients with a short deceleration time (p = 0.04 and p = 0.02, respectively). In a Cox model, which included initial ejection fraction, infarct location, and infarct size, deceleration time on day 1 was the only significant predictor of five year mortality.

CONCLUSIONS

A short deceleration time on day 1 after acute myocardial infarction can identify patients who are likely to undergo left ventricular remodelling in the following year. These patients have a higher one year and five year cardiac mortality.

Wall motion of noninfarcted myocardium. Relationship to regional and global systolic function and to early and late left ventricular dilation

We studied the wall motion of the noninfarcted area and its role in left ventricular remodeling. The study group consisted of 43 patients with a first Q-wave acute myocardial infarction and single-vessel disease. Cardiac catheterization was performed at the first week, and was repeated six months later. Left ventricular volumes, wall motion at the infarcted and noninfarcted area, ejection fraction and infarction-related artery status were quantified. Hyperkinesia was only found at the first week in 22% of cases, and at the sixth month in 26% of cases. Wall motion at the noninfarcted area correlated with wall motion at the infarcted area (one week: r=0.53 p<0.0001; six months: r=0.52 p=0.01), ejection fraction (one week: r=0.69 p<0.0001; six months: r=0.56 p=0.006), end-diastolic volume (one week: r=-0.48 p=0.002; six months: r=-0.48 p=0.02) and end-systolic volume (one week: r=-0.70 p<0.0001; six months: r=-0.64 p=0.001). The improvement of the noninfarcted area (from the first week to the sixth month) was only related to basal (one week) wall motion in this area (r=-0.58 p=0.003). We conclude that after an intermediate-large infarction, most patients exhibit a normal or hypokinetic noninfarcted area. Patients with a more depressed infarcted area show poorer contractility at the noninfarcted area. area exhibit greater progressive improvement.

Old and new paradigms on diastolic function in acute myocardial infarction

Although left ventricular systolic function after myocardial infarction has been the subject of detailed studies, diastolic phenomena during and after acute myocardial infarction are less well understood. The reasons for this are that catheterization studies, which are the gold standard, are not practical for serial measurements, whereas Doppler echocardiographic evaluation of diastolic function is based on the assessment of left ventricular filling only rather than on the pressure-volume relation. This article reviews invasive and noninvasive studies of diastolic function after myocardial infarction and proposes an integrated approach to the assessment of systolic and diastolic function that are simultaneously but independently impaired after myocardial infarction.

Association of Killip class on admission and left ventricular dilatation after myocardial infarction: a closer look into an old clinical classification

BACKGROUND

Early identification of patients in whom left ventricular dilatation is likely to occur may have important therapeutic implications. Thus the purpose of this study was to evaluate the relation between Killip class on admission and subsequent left ventricular dilatation after acute myocardial infarction.

METHODS AND RESULTS

We serially evaluated 129 consecutive patients by two-dimensional and Doppler echocardiography on days 1, 2, 3, and 7, at 3 and 6 weeks, and at 3, 6, and 12 months after infarction. Killip class on admission >1 was found in 29 of 129 (22.5%) patients, and they had significantly higher end-systolic and end-diastolic volume indexes and wall motion score index from day 1 onward compared with patients with Killip class 1, whereas ejection fraction was lower during the follow-up period in these patients. Patients with Killip class >1 showed the progressive increase of end-diastolic (68.2 +/- 2.99 to 88.0 +/- 7.55 ml/m2, p = 0.001) and end-systolic volume indexes (43.9 +/- 2.67 to 56.3 +/- 6. 18 ml/m2, p = 0.004) during the follow-up period, whereas ejection fraction and wall motion score index remained unchanged. In patients with Killip class 1, end-systolic volume index did not change (30.8 +/- 1.06 to 33.8 +/- 2.15 ml/m2, p = 0.064), ejection fraction increased (49.3% +/- 0.99% to 51.8% +/- 1.17%, p = 0.027), and wall motion score index decreased (1.50 +/- 0.03 to 1.35 +/- 0.04, p < 0. 001). End-systolic volume index was the major independent correlate of Killip class, followed by history of diabetes and peak creatine kinase level. No association was found between Doppler indexes of diastolic filling and Killip class on admission.

CONCLUSIONS

Killip class >1 on admission is associated with both acute and long-term left ventricular dilatation. On the other hand, Killip class 1 is associated with favorable left ventricular functional indices, and it appears that left ventricular function in these patients may improve over time. Initial end-systolic volume index but not ejection fraction is the major correlate of Killip class.

Heterogeneous fate of perfusion and contraction after anterior wall acute myocardial infarction and effects on left ventricular remodeling

After acute myocardial infarction, patency of infarct vessel and extent of left venticular (LV) dysfunction are major determinants of ventricular remodeling. Spontaneous, delayed reperfusion in the infarct zone occurs in a sizeable number of patients well after the subacute phase. The aim of this study was to determine the relation between the occurrence of this spontaneous, delayed reperfusion and LV remodeling. In 84 patients, resting LV volumes, topography, regional function, and perfusion were quantitatively evaluated by 2-dimensional echocardiography and sestamibi tomography 5 weeks (study 1) and 7 months (study 2) after anterior Q-wave infarction. At study 2, LV end-diastolic volume increased by > 15% in 17 patients (20%, LV remodeling); they had already had at study 1 significantly larger LV volumes, more severe hypoperfusion and wall motion abnormalities, and greater regional dilation than patients with stable LV volumes. Delayed reperfusion occurred in 8 of 17 patients with and in 42 of 67 patients without LV remodeling (47% vs 63%; p=NS). At study 2, LV regional dilation and end-diastolic volumes were stable in patients with, but increased in patients without, spontaneous reperfusion (from 25+/-24% to 29+/-26% at study 2 [p<0.05] and from 65+/-14 to 68+/-18 ml/m2 [p <0.05]). At multivariate analysis, however, regional ventricular dilation at study 1 was the sole predictor of further LV remodeling. Thus, after acute myocardial infarction, spontaneous reperfusion occurring after 5 weeks plays only a minor role in influencing LV remodeling. Benefits from delayed reperfusion seem limited to patients with preserved LV volumes; patients with an enlarged left ventricle 5 weeks after acute infarction are prone to further LV remodeling, irrespective of delayed reperfusion.

Left ventricular dilatation after myocardial infarction: ACE inhibitors, beta-blockers, or both?

Left ventricular (LV) dilatation after myocardial infarction (MI) is a major predictor of prognosis and identifies which patients will develop heart failure. Left ventricular dilatation or remodeling starts immediately after MI and progresses in the chronic phase of heart failure. Factors influencing remodeling, such as infarct size and neurohumoral activation, including the sympathetic and renin-angiotensin system, are discussed. Remodeling can be affected by reduction of infarct size and inhibition of neurohumoral activation. The effect of thrombolysis, beta-blockade, and angiotensin-converting enzyme (ACE) inhibition in the acute phase after MI and in the chronic phase of heart failure on remodeling are discussed. On the basis of beneficial effects of ACE inhibition and beta-blockade in acute MI and in chronic heart failure, a treatment strategy is proposed in which both ACE inhibition and beta-blockade are started early after MI. Depending on infarct size and ventricular function, continued treatment in the chronic phase of heart failure must be considered.

Echocardiography to understand remodeling and to assess prognosis after acute myocardial infarction

Ventricular remodeling indicates a dynamic process, starting with and after acute myocardial infarction, as a result of structural and functional modifications which involve acutely and chronically both the infarcted and noninfarcted zones of the left ventricle. The most effective way to prevent or minimize post-MI cardiac remodeling is to limit the extent of the initial insult. This can be partly achieved by early myocardial reperfusion obtained by different strategies including thrombolysis. In 6405 patients of the GISSI-3 trial, 2D echocardiographic studies were available at predischarge, at 6 weeks and at 6 months after the infarction. The increase in left ventricular volumes over time was reduced by 6-week lisinopril treatment. Patients randomized to lisinopril had smaller volume also at 6 months, after withdrawal of treatment at 6 weeks. Important prognostic indications can also be derived from predischarge echocardiography, since larger quartiles of left ventricular volumes and lower quartile of ejection fraction indicates higher risk of mortality and non-fatal congestive heart failure in the 6 months after the index event, even in the relatively low risk general population of infarcts of the GISSI-3.

Association of ventricular arrhythmias with left ventricular remodelling after myocardial infarction

OBJECTIVE

To assess the relation between ventricular arrhythmias after myocardial infarction and left ventricular remodelling.

DESIGN

Prospective study with consecutive patients.

METHODS

97 patients with acute myocardial infarction underwent serial echocardiographic examinations (days 1, 2, 3, and 7, and after 3 weeks) to determine end diastolic volume, end systolic volume, and ejection fraction; volumes were normalised for body surface area and expressed as indices. Holter monitoring was performed on the day of the final echocardiogram. Coronary angiography was performed in 88 patients before hospital discharge.

RESULTS

Complex ventricular arrhythmias (defined as Lown class 3-5) were found in 16 of 97 patients. In logistic regression models, variables predictive of complex ventricular arrhythmias were end systolic volume index on admission (b = 0.054, P = 0.015) and end diastolic volume index after three weeks (b = 0.034, P = 0.012). Complex arrhythmias were also related to the increase of end diastolic and end systolic volume indices throughout the study (F = 5.62, P = 0.046, and F = 6.42, P = 0.017, respectively by MANOVA). A two stage linear regression model of ventricular volume versus time from infarct showed that both intercept (initial volume) and slope (rate of increase) were higher for patients with complex arrhythmias in both diastole and systole (P < 0.001 for all).

CONCLUSIONS

Complex ventricular arrhythmias after myocardial infarction are related to the increase of left ventricular volume rather than to depressed ejection fraction. Complex arrhythmias may be an aetiological factor linking left ventricular remodelling with higher mortality, but larger follow up studies of patients with progressive left ventricular dilatation after myocardial infarction are necessary to answer these questions.

Role of infarction artery status in left ventricular remodeling after acute myocardial infarction

The aim of this study was to evaluate the relation between the infarction artery status and left ventricular volumes, independently of regional ventricular dysfunction, at 4-6 weeks after a first myocardial infarction. The study group consisted of 100 patients, of whom 80 received thrombolytic treatment. Coronary and contrast left ventricular angiograms were performed at 36+/-5 days postinfarction. Left ventricular end-diastolic and end-systolic volumes were measured. The centerline chord motion method was used to calculate the extent of wall motion abnormality (percentage of chords with hypokinetic motion) and its severity (maximum units of S.D. below the normal wall motion reference). Minimum lumen diameter, patency and collateral flow in the infarction artery were also analyzed. Eight patients (group I) showed occlusion with poor collateral flow in the infarction artery, 22 patients (group II) occlusion with good collateral flow, 38 patients (group III) severe residual stenosis (minimum lumen diameter < or = 1 mm), and 32 patients (group IV) non-severe residual stenosis (minimum lumen diameter > 1 mm). Patients from group I presented greater wall motion abnormality in terms of both extent (P=0.005) and severity (P=0.007), and greater end-diastolic (P=0.07) and end-systolic (P=0.0008) volumes; there were no differences among groups II, III and IV. By stepwise multivariate regression analysis, the extent of wall motion abnormality was the main determinant of end-diastolic (P=0.0001) and end-systolic (P=0.0001) volumes; occlusion with poor collateral flow was also a significant independent factor for end-systolic volume (P=0.03). Total occlusion (including both with and without collaterals) and the minimum lumen diameter did not correlate with end-diastolic and end-systolic volumes. We concluded that (A) the extent of regional dysfunction is the primary determinant of left ventricular volumes at 4-6 weeks postinfarction. (B) The status of the infarction artery is a weak predictor of end-diastolic volume, which is the best descriptor of ventricular remodeling, although occlusion with poor collateral flow is associated to larger end-systolic volume.

Coronary recanalization by elective angioplasty prevents ventricular dilation after anterior myocardial infarction

OBJECTIVES

In a prospective study we evaluated whether late recanalization of the left anterior descending coronary artery (LAD) affects ventricular volume and function after anterior myocardial infarction.

BACKGROUND

Persistent coronary occlusion after anterior myocardial infarction leads to ventricular dilation and heart failure.

METHODS

We studied 73 consecutive patients with acute anterior myocardial infarction as a first cardiac event; all had an isolated lesion or occlusion of the proximal LAD. Six patients died before hospital discharge. The 67 survivors were classified into two groups: group I (patent LAD and good distal flow, n = 40) and group II (LAD occlusion or subocclusion, n = 27). The 20 patients in group I who had significant residual stenosis and all patients in group II underwent elective percutaneous transluminal coronary angioplasty (PTCA) within 18 days of myocardial infarction. The procedure was successful in 17 patients in group I (group IB) and in 16 patients in group II (group IIA): in the remaining 11 patients of group II, patency could not be reestablished (group IIB). Left ventricular volumes, ejection fraction and a dysfunction score were measured by echocardiography on admission, before PTCA, at discharge and after 3 and 6 months.

RESULTS

Although cumulative ST segment elevation was similar in groups I and II, ejection fraction and dysfunction score were significantly worse in group II. However, ventricular function and volumes progressively improved in group IIA, whereas group IIB exhibited progressive deterioration of function (dysfunction score [mean +/- SD] increased from 21 +/- 6 to 25 +/- 8, p < 0.05; ejection fraction decreased from 43 +/- 10% to 37 +/- 11%, p < 0.05); and end-systolic volume increased from 34 +/- 10 to 72 +/- 28 ml/m2, p < 0.05). Patients in group IIB also had worse effort tolerance, higher heart rate at rest, lower blood pressure and significantly greater prevalence of chronic heart failure.

CONCLUSIONS

Delayed PTCA of an occluded LAD can frequently restore vessel patency. Success appears to be associated with better ventricular function and a lack of chronic dilation. Large randomized studies are warranted to evaluate the effect of delayed PTCA on late mortality.

Left ventricular wall motion score as an early predictor of left ventricular dilation and mortality after first anterior infarction treated with thrombolysis. The CATS Investigators Group

To recognize patients prone to subsequent left ventricular dilation after the acute phase of a myocardial infarction treated with thrombolysis, we studied 233 patients with a first anterior infarction, treated with thrombolysis, with 2-dimensional echocardiography within 12 hours after admission and 3 months later. A wall motion score index (WMSI) and left ventricular volumes were assessed, and enzymatic infarct size was expressed as cumulative alphahydroxybutyrate dehydrogenase determined in the first 72 hours after infarction. Patients who died (17 of 233, 7%) after a mean follow-up of 517 days had a significantly higher acute WMSI (2.1 +/- 0.3, mean +/- SD) than those who survived (1.9 +/- 0.4)(p=0.006). With use of this cutoff value for 2 WMSI, ventricles with an acute WMSI < or = 2 (62%) showed no increase in end-diastolic volume index (EDVI) or end-systolic volume index (ESVI), whereas ventricles with an acute WMSI >2 (38%) showed a significant increase in ESVI (6.1 +/- 12.2 ml/m2) and in EDVI (10.3 +/- 16.6 ml/m2) in the first 3 months. Using a cutoff value of 1,000 U/L for cumulative alphahydroxybutytrate dehydrogenase, only infarcts with a value of >1,000 U/L (52%) caused a significant increase in EDVI (10.8 +/- 14.3 ml/m2) and ESVI (6.5 +/- 10.0 ml/m2) in the first 3 months. Thus, acutely assessed WMSI of >2 can readily predict subsequent dilation in patients with a first anterior infarction treated with streptokinase and is a good predictor of mortality. Enzymatic infarct size also is a predictor of dilation, although not available until 3 days after infarction.

Acute and long-term effects of thrombolysis after anterior wall acute myocardial infarction with serial assessment of infarct expansion and late ventricular remodeling

This study investigates the impact of thrombolysis on infarct expansion and subsequent left ventricular (LV) remodeling in patients with anterior wall acute myocardial infarction (AMI). We evaluated 51 consecutive patients (24 treated with thrombolysis) with anterior wall AMI by 2-dimensional echocardiography in the following sequence: days 1, 2, 3, and 7, after 3 and 6 weeks, and after 3, 6, and 12 months. LV end-diastolic and end-systolic volume indexes were determined from apical 2- and 4-chamber views using Simpson's biplane formula. Infarct and total LV perimeters were determined in the same views and their ratio expressed as infarct percentage. Infarct expansion was defined as: (1) an increase in infarct percentage and total perimeter >5% on days 2 to 3 in either of the views, or (2) initial infarct percentage >50% with an increase in total perimeter >5% on days 2 to 3. Coronary angiography was performed in 43 patients before discharge, and patency of the infarct-related artery was assessed using Thrombolysis in Myocardial Infarction trial criteria. Infarct expansion was detected in 23 patients. Infarct perimeter steadily decreased in patients with versus without thrombolysis and in patients with patent versus occluded infarct-related arteries. Furthermore, by logistic regression, thrombolysis (p = 0.007) and potency of the infarct-related artery (p = 0.02) were strong negative predictors of expansion, whereas initial infarct perimeter (p = 0.009) was directly associated with subsequent expansion. End-systolic volume index was higher in patients with expansion from day 1 (p = 0.003) through the end of the study (p = 0.021), and end-diastolic volume index was higher in these patients from day 2 (p = 0.012) through 12 months (p = 0.015). Thus thrombolysis, initial infarct size, and infarct-related artery patency are major predictors of infarct expansion after anterior wall AMI.

Serial assessment of left ventricular chamber stiffness after acute myocardial infarction

Left ventricular (LV) systolic function after acute myocardial infarction (AMI) has been the subject of detailed studies during the last decade, but diastolic phenomena during and after AMI are less well understood. Recently, it has been shown that early filling deceleration time accurately predicted LV chamber stiffness in an experimental model. To assess changes of LV stiffness after AMI, we studied 116 consecutive patients with 2-dimensional and Doppler echocardiographic examinations 1, 2, 3, 7, 21, and 42 days after AMI. Coronary angiography was performed in 101 patients. For the entire study group, deceleration time decreased nonsignificantly on day 2 and subsequently increased on days 3 (p = 0.001) and 7 (p = 0.036), returning toward initial values afterward. Deceleration time was shorter in large (peak creatine kinase level >1,000 U/L) versus small infarcts (p = 0.0008) and in patients with anterior versus inferior AMI (p = 0.02); there was no difference between patients with good and poor (< or = 45%) ejection fraction. These data indicate that increased LV stiffness can be detected 24 to 48 hours after AMI, but returns to normal within several days. Chamber stiffness is higher in large and anterior infarcts, but appears to be independent of LV systolic function.