Surgically remediable complications of myocardial infarction

Mechanical Circulatory Support in Cardiogenic Shock due to Structural Heart Disease

Despite advances in cardiovascular care, managing cardiogenic shock caused by structural heart disease is challenging. Patients with cardiogenic shock are critically ill upon presentation and require early disease recognition and rapid escalation of care. Temporary mechanical circulatory support provides a higher level of care than current medical therapies such as vasopressors and inotropes. This review article focuses on the role of hemodynamic monitoring, mechanical circulatory support, and device selection in patients who present with cardiogenic shock due to structural heart disease. Early initiation of appropriate mechanical circulatory support may reduce morbidity and mortality.

An Overview of FGF-23 as a Novel Candidate Biomarker of Cardiovascular Risk

Fibroblast growth factor-23 (FGF)-23 is a phosphaturic hormone involved in mineral bone metabolism that helps control phosphate homeostasis and reduces 1,25-dihydroxyvitamin D synthesis. Recent data have highlighted the relevant direct FGF-23 effects on the myocardium, and high plasma levels of FGF-23 have been associated with adverse cardiovascular outcomes in humans, such as heart failure and arrhythmias. Therefore, FGF-23 has emerged as a novel biomarker of cardiovascular risk in the last decade. Indeed, experimental data suggest FGF-23 as a direct mediator of cardiac hypertrophy development, cardiac fibrosis and cardiac dysfunction via specific myocardial FGF receptor (FGFR) activation. Therefore, the FGF-23/FGFR pathway might be a suitable therapeutic target for reducing the deleterious effects of FGF-23 on the cardiovascular system. More research is needed to fully understand the intracellular FGF-23-dependent mechanisms, clarify the downstream pathways and identify which could be the most appropriate targets for better therapeutic intervention. This review updates the current knowledge on both clinical and experimental studies and highlights the evidence linking FGF-23 to cardiovascular events. The aim of this review is to establish the specific role of FGF-23 in the heart, its detrimental effects on cardiac tissue and the possible new therapeutic opportunities to block these effects.

Syndromes of Acute Left Ventricular Failure

The syndrome of acute left ventricular failure, manifesting as pulmonary edema and/or cardiogenic shock, occurs in many different clinical settings, has many different causes, and variable treatment strategies. Most commonly it is seen as a complication of acute myocardial infarction where loss of myocardial tissue results in ineffective systolic performance of the left ventricle. Urgent percutaneous transluminal coronary angioplasty may have a significant impact on outcome in this setting. Other complicating events following myocardial infarction may also precipitate left ventricular failure including papillary muscle dysfunction and ventricular septal defect. The syndrome of acute left ventricular failure is also commonly seen in patients with chronic congestive cardiac failure whereby myocardial infarction, arrhythmia and even minor increases in salt intake can precipitate acute decompensation. Other conditions such as fulminant myocarditis, bacterial endocarditis and disease processes characterized by diastolic dysfunction can all cause acute left ventricular failure. Moreover, cardiac function may be depressed in septic shock by the presence of cardiodepressant factors. In summary, acute left ventricular failure is a syndrome with a diverse etiology. Specific diagnosis of the particular cause is crucial to appropriate management.

Cardiac CT and MRI guide surgery in impending left ventricular rupture after acute myocardial infarction

We report the case of a 67 year-old patient who presented with worsening chest pain and shortness of breath, four days post acute myocardial infarction. Contrast enhanced computed tomography of the chest ruled out a pulmonary embolus but revealed an unexpected small subepicardial aneurysm (SEA) in the lateral left ventricular wall which was confirmed on cardiac magnetic resonance imaging. Intraoperative palpation of the left lateral wall was guided by the cardiac MRI and CT findings and confirmed the presence of focally thinned and weakened myocardium, covered by epicardial fat. An aneurysmorrhaphy was subsequently performed in addition to coronary bypass surgery and a mitral valve repair. The patient was discharged home on post operative day eight in good condition and is feeling well 2 years after surgery.

Transcatheter closure of intracardiac shunts

Intracardiac shunts, such as atrial septal defects (ASDs), patent foramen ovales (PFOs), and ventricular septal defects (VSDs), are common forms of congenital or acquired heart disease. Traditional treatment has consisted of surgical closure. Transcatheter closure using implantable devices is now an alternative approach to the treatment of these lesions. Transcatheter closure offers advantages over surgical closure: 1) it is less invasive, resulting in shorter recovery times, less hospital time, and no scarring; 2) it avoids the deleterious neurocognitive effects of cardiopulmonary bypass; 3) it avoids the proarrhythmic effects of atrial or ventricular incisions; and 4) it is potentially less costly. Device closure of secundum ASDs is the procedure of choice. Device closure of PFOs can be performed under humanitarian device exemption (HDE) guidelines, although the indications for this procedure and its effectiveness compared with medical management remain controversial. Ongoing studies are addressing these issues. Transcatheter closure of muscular VSDs is an alternative to surgical treatment, especially for apical defects or those anterior to the moderator band. The CardioSEAL device (NMT Medical, Boston, MA) has HDE status for this purpose and the Amplatzer muscular VSD device (AGA Medical Corp., Golden Valley, MN) is being reviewed by the US Food and Drug Administration for market approval. Phase 1 investigations are underway for device closure of perimembranous VSDs using the Amplatzer perimembranous VSD device (AGA Medical Corp.). Until more data are available, surgical closure of perimembranous VSDs is still the procedure of choice. Closure of postinfarct VSDs can also be accomplished using intracardiac devices; however, this remains a high-risk procedure. Early experience compares favorably with surgical closure. Transcatheter device closure of intracardiac defects is a relatively new procedure. Long-term data for these procedures are currently lacking and, therefore, recommendations regarding the use of these devices will continue to evolve with time.

Surgical Repair of Mechanical Complications of Myocardial Infarction

Mechanical complications of acute myocardial infarction are estimated to account for 25,000 fatalities yearly in the United States. The diagnosis necessitates a high degree of clinical suspicion. Once recognized, prompt surgical intervention is necessary because if left untreated the condition frequently causes a fatal outcome. The main determinants of survival are the preoperative hemodynamic status of the patient, the presence of multisystem failure at presentation, and concomitant revascularization during repair of the defect. Because ischemic heart disease remains the leading cause of death in such patients following repair, coronary artery bypass should be considered and, whenever possible, performed in conjunction with repair of the postinfarct mechanical complication.

Transcatheter closure of postinfarction ventricular septal defects using the new Amplatzer muscular VSD occluder: Results of a U.S. Registry

The objective of this study was to assess the immediate and mid-term results of transcatheter closure of postinfarct muscular ventricular septal defects (VSDs) using the new Amplatzer postinfarct muscular VSD device (PIMVSD). Ventricular septal rupture occurs in 0.2% of myocardial infarcts and remains associated with very high morbidity and mortality. Data were prospectively collected for 18 patients who underwent attempted device closure of postinfarction VSDs between 2000 and 2003. Five patients underwent the closure in the acute phase (within 6 days from the infarct); the remaining patients underwent closure on day 14-95 after the diagnosis of the infarct. Outcome parameters included procedural success, evidence of residual shunts on echocardiography, and occurrence of procedure-related complications. The procedure was successful in deploying a device across the VSD in 16 of 18 patients. The 30-day mortality was 28%. Eleven patients are still alive and have been followed up for a median of 332 days. Two patients required a second procedure to close a residual VSD. At the most recent outpatient follow-up, the VSD was completely closed in two patients, six patients had a trivial or small residual shunt, and two patients had a moderate residual shunt. We conclude that percutaneous device closure of postinfarction VSDs using the Amplatzer PIMVSD occluder appears to be safe and effective. Further trials are required to assess long-term efficacy and compare the results with those of surgical closure.

Rupture of both papillary muscles after acute myocardial infarction: a case report

The authors report a case of transthoracic echocardiographic left ventriculography and surgical pathology findings of a patient with rupture of both papillary muscles after acute myocardial infarction.

Mitral regurgitation following acute myocardial infarction

Mitral valve regurgitation (MR) is a frequent Doppler echocardiographic finding in patients after acute myocardial infarction (AMI) and an independent predictor of long-term cardiovascular mortality. Reported risk factors include advanced age, prior myocardial infarction, infarct extension, and recurrent ischemia. During the early phase of AMI, transient ischemic MR is common and rarely causes hemodynamic compromise. However, when several chordae tendineae or a papillary muscle ruptures, acute left atrial and ventricular volume overload ensues, leading to abrupt hemodynamic deterioration with cardiogenic shock. Auscultation may be unrevealing due to decreased turbulence. Hence, the importance of a high index of suspicion for acute MR in any patient with acute pulmonary edema in the setting of AMI, especially if left ventricular systolic function is well preserved. Later, ventricular remodeling may lead to MR through annular dilatation or papillary muscle migration with malcoaptation of the leaflets. The widespread availability, ease of use and non-invasive nature of Doppler echocardiography have made it the standard diagnostic tool for detecting MR. Mechanical reperfusion of the infarct-related artery seems to be superior to fibrinolysis in decreasing its incidence acutely and in the long run. Nevertheless, when acute severe MR occurs, unless rapidly diagnosed and treated, this dreaded complication is associated with high morbidity and mortality. Prompt surgical intervention after hemodynamic stabilization is essential to ensure a good short-term and long-term prognosis. This review discusses the incidence, long-term prognosis, associated risk factors, complex pathophysiology, time of occurrence, clinical manifestations, diagnosis, and management of patients with MR after AMI.

Cardiogenic shock due to acute severe mitral regurgitation complicating acute myocardial infarction: a report from the SHOCK Trial Registry. SHould we use emergently revascularize Occluded Coronaries in cardiogenic shocK?

OBJECTIVES

Our objective was to define the outcomes of patients with cardiogenic shock (CS) due to severe mitral regurgitation (MR) complicating acute myocardial infarction (AMI).

BACKGROUND

Methods for early identification and optimal treatment of such patients have not been defined.

METHODS

The SHOCK Trial Registry enrolled 1,190 patients with CS complicating AMI. We compared 1) the cohort with severe mitral regurgitation (MR, n = 98) to the cohort with predominant left ventricular failure (LVF, n = 879), and 2) the MR patients who underwent valve surgery (n = 43) to those who did not (n = 51).

RESULTS

Shock developed early after MI in both the MR (median 12.8 h) and LVF (median 6.2 h) cohorts. The MR patients were more often female (52% vs. 37%, p = 0.004) and less likely to have ST elevation at shock diagnosis (41% vs. 63%, p < 0.001). The MR index MI was more frequently inferior (55% vs. 44%, p = 0.039) or posterior (32% vs. 17%, p = 0.002) than that of LVF and much less frequently anterior (34% vs. 59%, p < 0.001). Despite having higher mean LVEF (0.37 vs. 0.30, p = 0.001) the MR cohort had similar in-hospital mortality (55% vs. 61%, p = 0.277). The majority of MR patients did not undergo mitral valve surgery. Those undergoing surgery exhibited higher mean LVEF than those not undergoing surgery; nevertheless, 39% died in hospital.

CONCLUSIONS

The data highlight opportunities for early identification and intervention to potentially decrease the devastating mortality and morbidity of severe post-myocardial infarction MR.

Three Different Coexisting Mechanical Complications of Myocardial Infarction Detected by Transthoracic and Transesophageal Echocardiography

An aneurysm, pseudoaneurysm, and interventricular septal rupture were detected by transthoracic and transesophageal echocardiography (TEE) in a 61-year-old man with anterior myocardial infarction. This case illustrates the value of these techniques in the assessment of mechanical complications associated with myocardial infarction.

Evolution of echocardiographic modalities in detection of postmyocardial infarction ventricular septal defect and papillary muscle rupture: study of 62 patients

Diagnostic sensitivity of various echocardiographic modalities was assessed for postinfarct ventricular septal defect (40 patients) and papillary muscle rupture (22 patients). Two-dimensional transthoracic echocardiography enabled direct visualization of ventricular septal defect in 68% and combined two-dimensional Doppler echocardiography was diagnostic in 95%. Papillary muscle rupture was directly visualized in 45%, and severe mitral regurgitation was present on Doppler color flow images in 100%. Transesophageal echocardiography was diagnostic in all nine patients (five with ventricular septal defect and four with papillary muscle rupture) in whom this modality was applied. Thus two-dimensional Doppler echocardiography (transthoracic and transesophageal if necessary) is highly sensitive in detecting postinfarct ventricular septal defect and papillary muscle rupture.

Mitral valve operation in postinfarction rupture of a papillary muscle: immediate results and long-term follow-up of 22 patients

The long-term clinical outcome was assessed in 22 patients (15 men and 7 women; mean age, 68 years) who underwent mitral valve replacement or repair for acute mitral regurgitation due to postinfarction rupture of a papillary muscle during the period 1981 through 1990 at the Mayo Clinic. All but three patients underwent operation within the first 3 weeks after acute myocardial infarction. The perioperative mortality was 27%, and the estimated actuarial survival rate at 7 years postoperatively was 47% and 64% for the entire group and for the patients who survived the operation, respectively. The concomitant performance of a coronary artery bypass grafting procedure was the only factor identified that improved both immediate and long-term survival. Patients with a decreased preoperative left ventricular ejection fraction (less than 45%) had somewhat greater short-term and long-term mortality than did those with a left ventricular ejection fraction of 45% or more, but the difference was only of borderline statistical significance. Other factors such as age, sex, severity of coronary artery disease, preoperative existence of congestive heart failure, and timing of the operation in relationship to occurrence of the infarction had no effect on survival. Of the 13 long-term survivors, 10 had significant clinical improvement in comparison with their preoperative state.

The successful surgical repair of a ruptured interventricular septum following a myocardial infarct in an 89 year old man

This case report describes the successful repair of an acquired ventricular septal defect following an anterior full thickness myocardial infarct in an 89 year old man. Four months after the infarct the patient was in severe congestive cardiac failure (NYHA Class IV), despite medical treatment, with signs of a ventricular septal defect. This was confirmed by echodoppler and cardiac catheterization. Surgical repair of the ventricular septal defect was performed. He made an uncomplicated recovery and two and a half years later is well and active. We believe he is the oldest patient who has had this operation successfully.

Two-dimensional echocardiography and Doppler color flow mapping in the diagnosis and prognosis of ventricular septal rupture

Doppler color flow mapping in conjunction with two-dimensional echocardiography was used to evaluate ventricular septal rupture after myocardial infarction (seven anterior and eight inferior) in 15 patients and to correlate these findings with cardiac catheterization and surgical or autopsy data. Ventricular septal rupture was diagnosed by turbulent flow traversing the ventricular septum. The direction and velocity of shunt flow was determined by color M-mode and conventional Doppler methods. In all patients, Doppler color flow mapping correctly defined the site of septal rupture, which occurred at areas of discordant septal wall motion or "hinge points" (six posterior inlet, three anterior inlet, and six apical trabecular septum). Each of three patients with moderate tricuspid regurgitation and three of four patients with right-to-left shunting during diastole died, and all had an elevated right ventricular end-diastolic pressure. Right ventricular wall motion index was significantly higher in the patients who died compared with those who survived (mean +/- SEM; 2.8 +/- 0.2 vs. 2.0 +/- 0.2, p = 0.012), but there was no difference in left ventricular wall motion index. The rupture size measured by Doppler color flow imaging (1.7 +/- 0.1 cm) correlated with the size determined during surgery or autopsy (1.8 +/- 0.2 cm, r = 0.68, p = 0.022) and the pulmonic-to-systemic shunt flow ratio by cardiac catheterization (2.4:1 +/- 0.3, r = 0.74, p = 0.004). Color-guided continuous-wave Doppler estimates of right ventricular systolic pressure (47 +/- 2 mm Hg) correlated with cardiac catheterization measurements (48 +/- 3 mm Hg, r = 0.90, p = 0.0002).(ABSTRACT TRUNCATED AT 250 WORDS)

Patterns of coronary artery disease in post-infarction ventricular septal rupture

Cardiac angiography was reviewed in 91 patients with post-infarction ventricular septal rupture. The results were compared with those of 123 stable survivors who had a positive submaximal exercise test early after infarction. Anterior infarction and occlusion of the infarct vessel were more common in those with ventricular septal rupture than in the comparison group. In the group with ventricular septal rupture there was more left ventricular damage, with aneurysm formation in two thirds, and coronary angiography showed more single than triple vessel disease. In the comparison group there was more triple vessel disease than single vessel disease. Angiographically demonstrable collaterals to the infarct territory were not seen or only very faintly seen in 82% of those with septal rupture. Well developed collaterals were seen in two thirds of the comparison group. These patterns of coronary disease suggest that ventricular septal rupture is more likely in patients with coronary occlusion and little or no collateral support to the infarct territory.

Hemodynamic abnormalities in acute myocardial infarction

Great strides have been made in the management of patients with acute myocardial infarction since the advent of coronary care units. However, congestive heart failure continues to be the major cause of in-hospital mortality. The accurate diagnosis and classification of hemodynamic abnormalities allow the application of specific therapies for each patient. Because clinicians can now routinely measure left and right ventricular preload, systemic and pulmonary vascular resistance, cardiac output, and arteriovenous oxygen difference, pharmacologic and surgical interventions can be applied in a scientific manner. In addition, mechanical complications can be promptly recognized and aggressively treated. Although the mortality rate for patients with severe left ventricular dysfunction after myocardial infarction remains high, expert management offers an improved prognosis for many patients.

Noninvasive detection by Doppler echocardiography of combined ventricular septal rupture and mitral regurgitation in acute myocardial infarction

The diagnosis of combined ventricular septal rupture and mitral regurgitation complicating acute myocardial infarction is difficult and in previously reported cases has required right and left heart catheterization. This study utilized simultaneous Doppler and two-dimensional echocardiography to diagnose these combined lesions in two cases. Doppler echocardiography should have its greatest impact in the early noninvasive diagnosis of these complications.

Papillary muscle rupture complicating acute myocardial infarction. Treatment with mitral valve replacement and coronary bypass surgery

Six cases of complete or partial rupture of the papillary muscle after acute myocardial infarction are presented. All cases were treated by mitral valve replacement and concomitant coronary bypass surgery. An average delay of 3 days between rupture and operation occurred in the four patients with rupture of the main muscle trunk. The operative mortality rate was 50 percent. Such patients present with acute, florid left ventricular failure secondary to the severe mechanical burden imposed on the newly infarcted heart. The resulting valvular incompetence must be corrected by urgent mitral valve replacement if survival is to be lengthened. Patients with partial or apical head ruptures have a lesser degree of regurgitation and symptoms are largely dependent on intrinsic ventricular function. Both of our patients with partial muscle rupture presented with severe heart failure 2 to 4 months later, and both did well postoperatively. We believe that prompt operation without prolonged attempts at medical stabilization is the key to decreasing operative mortality, especially in instances of complete muscle rupture. Since ischemic heart disease remains the leading cause of death in such patients, coronary artery bypass surgery should be performed in conjunction with valve replacement.

Papillary muscle rupture complicating acute myocardial infarction: analysis of 17 patients

The records of 17 patients (10 men and 7 women) with the diagnosis of acute papillary muscle rupture secondary to acute myocardial infarction (AMI) were reviewed to determine the clinical course and pathologic features of this entity. Eight patients underwent operation after papillary muscle rupture had been diagnosed, and 9 had the diagnosis confirmed at autopsy without a prior surgical procedure. The ages were 44 to 80 years (mean 64). The site of AMI was inferolateral in 15 and anterior in 2. The recorded onset of mitral regurgitation ranged from less than 24 hours to 28 days after AMI (mean 6 days). Of the 11 patients presenting with pulmonary congestion alone, 6 remained stable and had subsequent mitral valve replacement and coronary artery bypass graft operation; however, 5 patients' condition initially stabilized with medical therapy and then suddenly deteriorated after a variable period (1 to 60 days), followed by death. Of the 6 patients who presented with systemic hypotension and pulmonary congestion, 4 were treated medically and died; 1 of the 2 who had surgical treatment survived. The extent of the AMI at autopsy was small and was limited to the subendocardium in half of the patients. Significant coronary artery disease was limited to a single vessel in 7 of 14 patients. The unpredictable and rapid clinical deterioration and the limited extent of coronary atherosclerotic disease and infarct size suggest that early surgical repair should be undertaken in patients with papillary muscle rupture after AMI.

Two dimensional echocardiographic diagnosis of partial papillary muscle rupture

Images

Echocardiographic visualization of the anatomic causes of mitral regurgitation resulting from myocardial infarction

A murmur of mitral regurgitation in patients with congestive heart failure after an acute myocardial infarction suggests a surgically correctable cause of the heart failure. Six patients who presented in this manner and who later underwent surgery have been evaluated by two-dimensional echocardiography (2DE). The underlying anatomical cause of the mitral regurgitation was correctly identified as papillary muscle rupture (2 cases), ruptured chordae tendineae (1 case) and papillary muscle fibrosis (3 cases).

Two-dimensional echocardiography is useful in evaluating patients with congestive heart failure who develop a systolic murmur after acute infarction, as it can detect surgically correctable structural defects.

Ventricular septal rupture: a review of clinical and physiologic features and an analysis of survival

Forty-one patients with postinfarction ventricular septal rupture were cared for in our hospital during 1971-1975. Cardiogenic shock developed after septal rupture in 55% of these patients. Shock was unrelated to site of infarction, extent of coronary artery disease, left ventricular ejection fraction, or pulmonary-to-systemic flow ratio, but mean pulmonary artery pressure was lower in shock than in nonshock patients. These observations suggest that shock was produced mainly by right ventricular impairment. Perioperative survival was much higher in patients who did not have shock preoperatively (14 of 17 [82+]) than in those who did (three of 11 [27%]). Magnitude of shunt, left ventricular ejection fraction, extent of coronary artery disease, and performance of aortocoronary bypass grafting were not distinctly correlated with perioperative survival. After a minimum 4-year follow-up, 76% of the perioperative survivors are alive, and none suffer more than New York Heart Association functional class II disability. All 13 unoperated patients (11 in shock) died within 3 months.

Two-dimensional echocardiographic identification of surgically correctable complications of acute myocardial infarction

The appearance of a new, loud systolic murmur in a patient with congestive heart failure after an acute myocardial infarction suggests a surgically correctable cause of the heart failure. Using two-dimensional echocardiography, we studied 14 patients who presented in this manner. Four patients had rupture of a papillary muscle with a flail mitral valve. All four had surgery; three survived. Five patients had fibrosis of the posteromedial papillary muscle. All five had surgery; three survived. Five patients had a ventricular septal defect. Three of the five had surgery; one survived. Two-dimensional echocardiography is useful in studying patients with a new systolic murmur and congestive heart failure after acute myocardial infarction to detect surgically correctable structural defects.

Cardiac rupture and ventricular septal defect in isolated right coronary artery disease

A patient is described who had both ventricular septal defect and then cardiac rupture with death within 24 hours of the onset of acute posteroinferior myocardial infarction. At autopsy he was found to have single-vessel disease involving the right coronary artery. Isolated disease of the right coronary artery can produce unexpected, fatal mechanical complications.

Management of ventricular septal rupture in acute myocardial infarction

Four patients with rupture of the interventricular septum after myocardial infarction are described. This condition carries a grave prognosis. Surgical repair of the septum is almost always urgently required if the left-to-right shunt is large (QP/WS > 3). Results are better if surgery can be deferred for six weeks to allow the infarcted area to heal and the tissues to be come firmer. This delay may be achieved by using a combination of agents to reduce afterload and to exert a positive inotropic effect. The timing of surgical intervention was an important factor in the survival of three of the four patients.

Predictors of late hospital death in acute myocardial infarction

Although death from ischemic heart disease occurs in the majority of cases within 24 hr of a new clinical event, study of patients selected by admission to hospital shows a mortality pattern in which most deaths from myocardial infarction happen after the first day. In one hospital, over the last 2 yr, 46% of deaths from infarction have happened from the fourth day onwards. Introduction of a coronary-care unit in this hospital has reduced hospital mortality in patients under 70 yr of age from approximately 21% in 1966-1967 to 13% in 1977-1979, mainly because of improved treatment of arrhythmias. With the decline of cardiac arrhythmias as a mode of dying in hospitals, mechanical complications of shock and cardiac failure now account for up to two-thirds of hospital deaths, with cardiac rupture probably next in importance, accounting for 15%-20% of deaths. Of these 3 mechanisms, death from cardiac failure is most likely to be "late" (from the fourth day onwards). Shock and cardiac failure are directly related to massive destruction of left ventricular myocardium. Therefore, major efforts aimed at reduction of late hospital mortality should be directed towards therapeutic measures, initiated very early after the onset of infarction, which might protect the threatened myocardial tissue and restrict infarct size.