Tissue doppler imaging predicts recovery of left ventricular function after recanalization of an occluded coronary artery

OBJECTIVES: We tested the hypothesis that the tissue Doppler imaging (TDI)-derived positive preejection velocity (+VIC) can predict the recovery of contractile function after revascularization in patients with a recent myocardial infarction. BACKGROUND: In experimental studies, the presence and extent of TDI-derived +VIC correlated with the extent of viable myocardium. METHODS: Forty-three patients with a large myocardial infarction and an occluded left anterior descending (n = 38) or dominant right coronary (n = 5) artery were selected. The median duration of occlusion was 24 h. Longitudinal myocardial velocities were recorded at rest by pulsed-wave TDI echocardiography 6 +/- 2 h after revascularization. Functional recovery was defined as an increase in segmental chordal shortening > or =10% at three-month follow-up left ventricular angiogram as compared with baseline. RESULTS: A good quality TDI signal was obtained in 309 of 324 analyzed segments (95.4%). Severe dysfunction was present in 198 segments of which 126 (64%) showed recovery at three-month follow-up. Sampling of all dysfunctional segments lasted 11 +/- 4 min per patient. Sensitivity, specificity, and accuracy of the +VIC to predict segmental recovery were 91%, 71%, and 84%, respectively. The percentage of segments that were dysfunctional at angiography but showed a +VIC correlated with improvement of both global left ventricular ejection fraction (r = 0.60, p = 0.001) and wall motion score index (r = -0.78, p < 0.0001) at follow-up. CONCLUSIONS: Assessment of +VIC by pulsed-wave TDI is a simple and accurate method that predicts recovery of contractile function after revascularization in patients with a recent myocardial infarction.     

Time course of left ventricular dilation after myocardial infarction: influence of infarct-related artery and success of coronary thrombolysis

Dilation of the left ventricle after myocardial infarction is common, occurs rapidly (within 2 weeks of infarction) and may be self-limited. To evaluate the time course of postinfarction left ventricular dilation and to assess the impact of successful coronary thrombolysis, serial radionuclide left ventricular volume analyses were performed in 36 patients undergoing attempted thrombolysis for acute transmural myocardial infarction. All patients underwent cardiac catheterization, coronary angiography and attempted thrombolysis within 7 h of the onset of symptoms. The site of coronary occlusion was the left anterior descending coronary artery in 17 patients, the right coronary artery in 18 and, in 1 patient, occluded bypass grafts to the right and left circumflex coronary arteries. Attempted reperfusion using a thrombolytic agent was successful in 22 individuals, occurring 5 +/- 1 h after the onset of symptoms. Gated radionuclide ventriculography was performed early (mean time 1 day after admission, n = 36), subacutely (mean time 11 days postinfarction, n = 36) and late after infarction (mean time 10.5 months, n = 25), and a geometric technique was used to measure serial left ventricular end-diastolic volume. Left ventricular end-diastolic volume for the entire group increased significantly (p less than 0.01) from 153 +/- 30 ml at baseline to 172 +/- 45 ml (at 11 days) to 220 +/- 63 ml (at 10.5 months). Twenty of 36 patients showed greater than 20% increase in left ventricular end-diastolic volume (dilation) with time. This appeared early in seven patients, occurred remote from infarction in seven others and showed a progressive pattern in six.(ABSTRACT TRUNCATED AT 250 WORDS)     

Delayed recovery of left ventricular function after recanalization of a chronic coronary occlusion.

An unusually prolonged course of recovery of severely impaired left ventricular (LV) function (EF 32%) was observed in a patient after recanalization of a chronically occluded LAD. Despite persistent vessel patency, LV function remained depressed for almost 2 years after the percutaneous transluminal coronary angioplasty until complete recovery (EF 82%) could be observed. The possibility of a delayed recovery should be considered when assessing new therapeutic strategies to improve LV function of chronically ischemic myocardium.     

The effect of recanalization of the occluded coronary artery in acute myocardial infarction on left ventricular function

In 20 patients with acute myocardial infarction a left ventriculogramwas obtained within 6 h after the onset of chest pain and againduring a follow-up study, 2–3 weeks later. In 17 patientsthe infarct-related vessel (IR V) could be recanalized withselective intracoronary infusion of a thrombolytic agent andwas still patent during the second study. In three other casesthe IR V was already patent during the first angiogram and remainedso at the time of the follow-up study. The ejection fractionof these 20 patients increased from 52 to 56% (P < 0.02). In eight other patients the infarct-related artery could notbe recanalized or was reoccluded at the time of the controlstudy. The ejection fraction of these patients with unsuccessfulrecanalization decreased from 49 to 37% (P<0.001). Analysis of regional function in eight patients with anteriorinfarction and seven patients with inferior infarction, allwith a successful recanalization and persistent patency of theinfarct-related vessels, suggests that improvement of globalejection fraction is only partially due to improvement of regionalpump function in the reperfused ‘infarct zone’ butmay also be caused by enhancement of regional function in otherwall regions or by changes in afterload.     

Radiofrequency recanalization of an occluded long segment left pulmonary artery in bidirectional cavopulmonary anastomosis

In patients with hypoplastic left heart syndrome who experience the Norwood surgical palliative program, development of the pulmonary artery branches is crucial. Balloon dilation and stenting may relieve potential stenosis but complete occlusion remains difficult to address with transcatheter therapy. We report the use of radiofrequency followed by balloon dilation and stenting to treat a long segment left pulmonary artery occlusion in a 15‐month‐old boy bidirectional Glenn. The left pulmonary artery was successfully recanalized with an excellent short‐term outcome. This further enhances the interest of radiofrquency for recanalization of occluded pulmonary artery branches, as an alternative to surgical reconstruction. © 2009 Wiley‐Liss, Inc.     

Reperfusion of the infarct-related coronary artery limits left ventricular expansion beyond myocardial salvage.

Previous echocardiographic data from the Gruppo Italiano per lo Studio della Streptochinasi nell' Infarto Miocardico (GISSI 1) trial suggest that the relation between left ventricular end-systolic volume and infarct size could be altered by thrombolysis, which would exert a restraining effect on end-systolic volume beyond its reducing effect on infarct size. Thus in 63 patients with one-vessel disease and a recent anterior myocardial infarction, we tested at angiography (1) if perfusion of the anterior descending coronary artery exerts any restraining effect on end-systolic volume above and beyond infarct size reduction and (2) if ejection fraction reflects such an additional, beneficial difference in the ventricular remodeling process. End-systolic volume was calculated using the Dodge method and the right anterior oblique projection, while infarct size was quantified according to the number of ventricular radii whose percent shortening fell below the mean -2 SD of a group of normal individuals. Patients were then divided into two groups according to the perfusion status of the vessel using Thrombolysis in Myocardial infarction (TIMI) criteria (TIMI grade 0 to 1: nonperfused vessel, 27 patients; TIMI grade 2 to 3: perfused vessel, 36 patients). For both groups there was a significant linear relation (p less than 0.001) between end-systolic volume and infarct size; as in our echocardiographic data, the regression lines relating volume to infarct size showed a different slope in the two populations so that, for large and matched infarcts, end-systolic volume was smaller in patients with a perfused vessel (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Time course of functional recovery after coronary artery bypass graft surgery in patients with chronic left ventricular ischemic dysfunction

Chronic left ventricular (LV) ischemic dysfunction, a condition often referred to as myocardial hibernation, is associated in humans with ultrastructural alterations of the myocytes, including the loss of myofilaments and the accumulation of glycogen. Given the severity of these structural changes, contractile function is unlikely to resume immediately upon revascularization. Therefore, the aim of the present study was to assess the time course of functional improvement after successful revascularization as well as its potential structural correlates. We studied 32 patients with coronary disease and chronic LV ischemic dysfunction who underwent bypass surgery. Dynamic positron emission tomography with N-13 ammonia and F-18 deoxyglucose to assess myocardial perfusion and glucose metabolism was performed in 29 patients. In all patients, a transmural biopsy was harvested from the center of the dysfunctional area, to quantify the increase in extracellular matrix and the presence of structurally altered cardiomyocytes. LV function was serially measured by digitized 2-dimensional echocardiography before and at 10 days, 2 months, and 6 months after revascularization. The time course of recovery of regional function was estimated from the monoexponential decrease in dysfunctional wall motion score. At follow-up, 19 patients had improved LV function, whereas 13 patients showed persistent dysfunction. Before revascularization, reversibly dysfunctional segments had higher myocardial blood flow (82 ± 29 vs 53 ± 21 ml · (min · 100 g)⁻¹, p = 0.044), higher glucose uptake (40 ± 16 vs 21 ± 9 μmol · (min · 100 g)⁻¹, p = 0.001), and less increase in extracellular matrix (25 ± 15% vs 46 ± 17%, p = 0.0008) than segments with persistent dysfunction. The extent to which function recovered was positively correlated with myocardial blood flow and negatively correlated with the increase in the extracellular matrix. In patients with reversible dysfunction, the return of segmental function was progressive and followed a monoexponential time course with a median time constant of 23 days (range 6 to 78). The rate of recovery correlated best with the proportion of altered cardiomyocytes in the biopsy. The present study thus indicates that the recovery of regional and global LV function after successful revascularization is progressive and follows a monoexponential time course that is influenced by the extent of the structural changes affecting cardiomyocytes.     

Collateralization of an occluded left internal mammary artery coronary bypass graft

The left internal mammary artery (LIMA) is frequently utilized in coronary artery bypass grafting (CABG); adequate visualization of the LIMA bypass graft during diagnostic angiography is critical for determination of myocardial blood supply. We present a novel case of angiography via a left transradial approach demonstrating an occluded LIMA coronary bypass graft with antegrade flow maintained via a collateral branch from the ipsilateral thyrocervical trunk. Given the prevalence of LIMA use in CABG, it is critical to be aware of unusual configurations, including collateralization of a proximally occluded LIMA graft as described in this report.     

Takotsubo-like left ventricular dysfunction with delayed recovery of left ventricular shape: a case report

A 70-year-old woman was admitted to our hospital because of left ventricular dysfunction, which was observed after permanent pacemaker implantation in another hospital. The left ventricular dysfunction was apical ballooning. Left ventriculography demonstrated takotsubo-like shape. However, the dysfunction did not improve immediately with medical treatment. In this case, 75% stenosis was observed in the left anterior descending artery. We suppose that this lesion corresponded to the delayed recovery of the dysfunction and performed coronary intervention. The takotsubo-like shape improved gradually for about 1 year. Whether the coronary intervention was effective for the recovery of the dysfunction is unclear, this clinical course was interesting in evaluating the delayed recovery of takotsubo-like left ventricular dysfunction.     

Influence of collateral filling of the occluded infarct-related coronary artery on prognosis after acute myocardial infarction.

Previous studies showed that long-term morbidity and mortality after acute myocardial infarction (AMI) are influenced by the presence or absence of anterograde flow in the infarct artery. In comparison with patients with anterograde flow, those whose infarct artery remains occluded are more likely to have unstable angina, recurrent AMI, congestive heart failure and sudden death. This study was performed to assess the influence of collateral filling of the infarct artery on long-term morbidity and mortality in surviving patients of initial AMI in whom the infarct artery was occluded. Over a 12.5-year period, 146 subjects (108 men and 38 women, aged 25 to 76 years) with AMI, no anterograde flow in the infarct artery, and no disease of other coronary arteries were medically treated and followed for 42 +/- 28 (mean +/- standard deviation) months. Of these subjects, 120 had angiographic evidence of collateral filling of the infarct artery (group I), whereas the remaining 26 did not (group II). The groups were similar in age, sex, cardioactive medications, left ventricular performance and infarct artery. They were also similar in incidence of unstable angina (19% of group I, 31% of group II; p = not significant [NS]), recurrent AMI (12% of group I, 8% of group II; p = NS), congestive heart failure (16% of group I, 12% of group II; p = NS) and cardiac death (16% of group I, 19% of group II; p = NS). Thus, angiographic evidence of collateral filling of the infarct artery in surviving patients of AMI exerts no demonstrable influence (beneficial or detrimental) on long-term morbidity or mortality.     

Determinants of left ventricular systolic function recovery after an acute coronary syndrome.

INTRODUCTION: Ischemic heart disease is a major cause of heart failure in western societies. However, the factors that may influence left ventricular function (LVF) recovery after an acute coronary syndrome (ACS) are still unclear. OBJECTIVE: To identify variables that may influence LVF evolution one year after ACS. METHODS: 104 patients hospitalized with ACS between 7/1/2001 and 12/31/2002 and with systolic dysfunction--defined as an echocardiographic ejection fraction (EF) < or = 45%--were randomly allocated to a planned coronary follow-up program (FUP) or a general cardiology clinic (GC); patients from both groups were also randomly referred to a structured cardiac rehabilitation program (CRP). EF was re-assessed at one year. We compared differences between patients who recovered left ventricular function (EF > 45%; group 1) and those who did not (group 2). RESULTS: One year after discharge, 44.2% of the patients had recovered function. There were no significant differences between the groups in gender (77.7 vs. 76.5% male), age (56 vs. 59 years), hypertension, diabetes, dyslipidemia, smoking habits or family history. A previous history of cardiovascular events was more frequent in group 2 (11.1% vs. 35.3%, p = 0.03). Cardiac catheterization was performed before discharge in 88.8% and 88.2% in groups 1 and 2 respectively (p = NS); no differences were found in coronary anatomy between the two groups. Angioplasty was performed in 54.2% in group 1 and 50% in group 2 (p = NS). There were no differences in the use of angiotensin-converting enzyme inhibitors (83.3% vs. 87.5%), beta-blockers (87.5% vs. 87.5%), nitrates (37.5% vs. 33.3%), aspirin (95.8% vs. 95.8%), statins (79.1% vs. 75%) or diuretics (20.8% vs. 45.8%). There was no significant difference in LVF recovery between patients randomized to FUP or GC (38.5% vs. 54.5%). 87.5% of patients who completed the CRP had normal EF at one year compared to 32.7% of patients not referred to the program (p = 0.009). Although EF improved in both groups, this improvement was greater in patients who completed a CRP (EF 8% vs. 5%, p = 0.003). CONCLUSION: A previous cardiovascular event and completion of a CRP were the only variables that influenced LVF recovery. Thus, enrollment in a CRP, in addition to standard therapy, could be an important therapeutic measure in patients with systolic dysfunction after ACS; our data suggest that these programs should be more widely used.     

Rate of left ventricular functional recovery by radionuclide angiography after exercise in coronary artery disease

To characterize determinants of the rate of recovery of left ventricular (LV) function after exercise-induced ischemia, sequential postexercise radionuclide angiography was performed prospectively in 38 consecutive patients with documented coronary artery disease (CAD). In each patient new or increased regional asynergy developed or absolute ejection fraction decreased at least 4% during exercise. Twenty patients showed immediate recovery of LV function after exercise (group 1) and 18 showed delayed recovery (group 2). Ejection fraction in the first postexercise period was significantly greater in group 1 (65 +/- 12%) than in group 2 (55 +/- 11%) (p less than 0.01). The mean number of coronary arteries with at least 70% diameter narrowing was greater in group 2 (2.7 +/- 0.5) than in group 1 (2.0 +/- 0.9) (p = 0.026); CAD score was also greater in group 2 than in group 1 (p = 0.005). The increase in LV end-diastolic volume from rest to end exercise was greater in group 2 than in group 1 (p = 0.005); neither the change in LV volume nor the change in heart rate or blood pressure after exercise separated the groups. The only independent predictor of the rate of functional recovery was the degree of exercise-induced regional myocardial asynergy (p less than 0.001). Thus, exercise radionuclide angiography in patients with CAD provides a model for evaluating postischemic myocardial function. Delayed functional recovery is associated with extensive exercise-induced regional asynergy as a result of severe CAD and is not primarily influenced by hemodynamic changes.     

The effects of reperfusion of infarct-related coronary artery on serum creatine phosphokinase and left ventricular function

In 31 patients with transmural myocardial infarction in whom coronary arteriography was performed within 8 hours after the onset of symptoms, we examined (1) the effect of restoration of coronary blood flow on serum CPK time-activity curve and (2) the relationship between cumulative CPKr and the left ventricular function in the chronic phase. We divided 31 patients into 2 groups: Group A consists of 19 patients in whom coronary reperfusion was established. Group B consists of 12 patients whose coronary artery remained occluded. In group A, the time required to reach peak serum CPK activity was significantly shorter than in group B. When comparing CPKr with percent abnormally contracting segment (%ACS) in 2 groups, correlation between CPKr and %ACS was not good, but it revealed linear relation in both group A and B. CPKr divided by %ACS (CPKr/%ACS) was significantly higher in group A than in group B. We conclude that reperfusion of infarct-related coronary artery changes serum CPK time-activity curve resulting in earlier appearance of peak serum CPK and that infarct size cannot be estimated by serum CPK level alone.     

Intravascular ultrasound-guided revascularization of a chronically occluded left main coronary artery

We describe a case of a left main coronary artery (LMCA) chronic total occlusion (CTO), which we elected to treat through percutaneous coronary intervention (PCI). In this case report, we briefly review the prevalence of LMCA CTO, discuss the feasibility of PCI versus surgical revascularization and highlight the importance of intravascular ultrasound in the guidance of these complex procedures.     

Patency of the infarct-related coronary artery and ventricular geometry.

The pathogenesis of acute myocardial infarction (AMI) involves a sudden thrombotic occlusion of a coronary artery. Spontaneous or pharmacologic thrombolysis may lead to myocardial salvage if patency is achieved within a narrow time window. However, patients in whom thrombolysis occurs late seem to demonstrate improved left ventricular (LV) function and prognosis, which may be independent of myocardial salvage. Preservation of normal LV geometry by reducing expansion of the infarcted segment is a likely mechanism for this benefit. Infarct expansion is most pronounced in patients with anterior wall AMI who have a persistently occluded infarct-related vessel. This process of expansion leads to early increases in LV volume and distortions of LV contour (abnormal LV geometry). Patients whose infarct segment is largest, patients who have manifested infarct expansion, and patients with a persistently occluded infarct-related artery are at highest risk for progressive LV dilation. Experimental data support the concept that reperfusion of occluded vessels that occurs too late for myocardial salvage will preserve LV geometry by limiting infarct expansion. Prospective clinical trials should address whether there is a late, "second time window" during which infarct expansion and distortions of LV geometry may be reduced by (1) therapy with thrombolytic agents applied late after infarction, (2) late mechanical reperfusion with percutaneous transluminal coronary angioplasty (PTCA) or related methods, and (3) load-reducing agents to decrease remodeling, such as angiotensin-converting enzyme inhibitors or nitroglycerin.