Mitral regurgitation following acute myocardial infarction

Management of Severe Mitral Regurgitation in Patients With Acute Myocardial Infarction: JACC Focus Seminar 2/5

Severe acute mitral regurgitation after myocardial infarction includes partial and complete papillary muscle rupture or functional mitral regurgitation. Although its incidence is <1%, mitral regurgitation after acute myocardial infarction frequently causes hemodynamic instability, pulmonary edema, and cardiogenic shock. Medical management has the worst prognosis, and mortality has not changed in decades. Surgery represents the gold standard, but it is associated with high rates of morbidity and mortality. Recently, transcatheter interventions have opened a new door for management that may improve survival. Mechanical circulatory support restores vital organ perfusion and offers the opportunity for a steadier surgical repair. This review focuses on the diagnosis and the interventional management, both surgical and transcatheter, with a glance on future perspectives to enhance patient management and eventually decrease mortality.

Acute Heart Valve Emergencies

Within the cardiac intensive care unit, prompt recognition of severe acute valvular lesions is essential because hemodynamic collapse can occur rapidly, especially when cardiac chambers have not had time for compensatory remodeling. Within this context, optimal medical management, considerations for temporary mechanical circulatory support and decisive treatments strategies are addressed. Fundamental concepts include an appreciation for how sudden changes in flow and pressure gradients between cardiac chambers can impact hemodynamic and echocardiographic findings differently compared to similarly severe chronic lesions, as well as understanding the main causes for decompensated heart failure and cardiogenic shock for each valvular abnormality.

Extracorporeal life support in mitral papillary muscle rupture: Outcome of multicenter study

BACKGROUND

Post-acute myocardial infarction papillary muscle rupture (post-AMI PMR) may present variable clinical scenarios and degree of emergency due to result of cardiogenic shock. Veno-arterial extracorporeal life support (V-A ECLS) has been proposed to improve extremely poor pre- or postoperative conditions. Information in this respect is scarce.

METHODS

From the CAUTION (meChanical complicAtion of acUte myocardial infarcTion: an InternatiOnal multiceNter cohort study) database (16 different Centers, data from 2001 to 2018), we extracted adult patients who were surgically treated for post-AMI PMR and underwent pre- or/and postoperative V-A ECLS support. The end-points of this study were in-hospital survival and ECLS complications.

RESULTS

From a total of 214 post-AMI PMR patients submitted to surgery, V-A ECLS was instituted in 23 (11%) patients. The median age was 61.7 years (range 46-81 years). Preoperatively, ECLS was commenced in 10 patients (43.5%), whereas intra/postoperative in the remaining 13. The most common V-A ECLS indication was post-cardiotomy shock, followed by preoperative cardiogenic shock and cardiac arrest. The median duration of V-A ECLS was 4 days. V-A ECLS complications occurred in more than half of the patients. Overall, in-hospital mortality was 39.2% (9/23), compared to 22% (42/219) for the non-ECLS group.

CONCLUSIONS

In post-AMI PMR patients, V-A ECLS was used in almost 10% of the patients either to promote bridge to surgery or as postoperative support. Further investigations are required to better evaluate a potential for increased use and its effects of V-A ECLS in such a context based on the still high perioperative mortality.

Multimodality Imaging of Sudden Cardiac Death and Acute Complications in Acute Coronary Syndrome

Sudden cardiac death (SCD) is a potentially fatal event usually caused by a cardiac arrhythmia, which is often the result of coronary artery disease (CAD). Up to 80% of patients suffering from SCD have concomitant CAD. Arrhythmic complications may occur in patients with acute coronary syndrome (ACS) before admission, during revascularization procedures, and in hospital intensive care monitoring. In addition, about 20% of patients who survive cardiac arrest develop a transmural myocardial infarction (MI). Prevention of ACS can be evaluated in selected patients using cardiac computed tomography angiography (CCTA), while diagnosis can be depicted using electrocardiography (ECG), and complications can be evaluated with cardiac magnetic resonance (CMR) and echocardiography. CCTA can evaluate plaque, burden of disease, stenosis, and adverse plaque characteristics, in patients with chest pain. ECG and echocardiography are the first-line tests for ACS and are affordable and useful for diagnosis. CMR can evaluate function and the presence of complications after ACS, such as development of ventricular thrombus and presence of myocardial tissue characterization abnormalities that can be the substrate of ventricular arrhythmias.

Treatment of severe acute mitral regurgitation following thoracoabdominal aortic aneurysm repair

An asymptomatic 63-year-old male with chronic type B aortic dissection underwent repair of an expanding 6.1 cm extent I thoracoabdominal aortic aneurysm. His postoperative course was complicated by respiratory failure from severe acute mitral regurgitation likely due to papillary muscle rupture, which was corrected with transcatheter MitraClip edge-to-edge repair.

Atypical Presentation of Acute Mitral Regurgitation Secondary to Papillary Muscle Rupture

Acute mitral regurgitation (MR) is a life-threatening condition presenting with severe decompensated heart failure due to sudden retrograde blood flow into the left atrium. The causes are broadly classified into ischemic and non-ischemic. Rapid and accurate diagnosis of acute MR and its potential causes is essential. This case uniquely highlights an atypical presentation of severe MR secondary to papillary muscle rupture without a known, identifiable cause. Therefore, suspicion of acute MR should be high if clinical symptoms are present, even without known risk factors, due to the high morbidity and mortality associated with delayed management.

Unilateral pulmonary oedema: a case report and literature review

Acute myocarditis is often secondary to an acute virus infection, which can be the first manifestation of upper respiratory tract symptoms, followed by chest tightness, shortness of breath, palpitations, chest pain and other non-specific symptoms. In severe cases, it can quickly progress to serious complications such as heart failure, shock and respiratory failure. Laboratory examinations can show an increase of myocardial injury markers, infection and inflammatory indicators. Cardiac ultrasound can detect the weakening of the myocardial contraction and valve regurgitation. On imaging, bilateral pulmonary oedema demonstrates symmetrical infiltration along the hilum of lung, called the “butterfly shadow”. This current case report describes a patient with unilateral pulmonary oedema caused by myocarditis that was initially misdiagnosed and treated as pneumonia. The patient was subsequently treated with the application of extracorporeal membrane oxygenation and he made a full recovery. A review of this case highlights that when a patient’s symptoms are not typical, a comprehensive examination and evaluation are required to avoid incorrect treatment.

Echocardiography in a critical care unit: A contemporary review

INTRODUCTION

Echocardiography is a rapid, noninvasive, and complete cardiac assessment tool for patients with hemodynamic instability. This review provides an overview of the evidence for current practices in critical care units (CCUs), incorporating the use of echocardiography in different etiologies of shock.

AREAS COVERED

: Relevant articles were extracted after searching on databases by two reviewers and incorporated in this review in a narrative style.

EXPERT OPINION

: In an acute scenario, a basic echocardiographic study yields prompt diagnosis, allowing for the initiation of treatment. The most common pathologies in shocked patients are identified promptly using two-dimensional (2D) and M-mode echocardiography. A more comprehensive assessment can follow after patients have been stabilized. There are four types of shock: (i) cardiogenic shock, (ii) hypovolemic shock, (iii) obstructive shock, and (iv) septic shock. All of them can be readily identified by echocardiography. As echocardiography is increasingly being used in an intensive care setting, its applications and evidence base should be expanded by randomized controlled trials to demonstrate patient outcomes in critical care.

Rupture of Papillary Muscle and Chordae Tendinae Complicating STEMI: A Call for Action

Papillary muscle rupture (PMR) or chordae tendinae rupture (CTR) is a rare but lethal complication after ST elevation myocardial infarction (STEMI). Due to the rarity of this condition, there are limited studies defining its epidemiology and outcomes. This is a retrospective study from Nationwide Inpatient Sample database from 2002 to 2014 of patients with STEMI and PMR/CTR. Outcomes of interest were incidence of in-hospital mortality, cardiogenic shock (CS), utilization of mechanical circulatory support (MCS) devices and mitral valve procedures (MVPs) among patients with and without rupture. We also performed simulation using the cardiovascular model to better understand the hemodynamics of severe mitral regurgitation and effects of different medications and device therapy. We identified 1,888 patients with STEMI complicated with PMR/CTR. Most of the patients were >65 years of age (65.3%), male (63.6%), and white (82.3%). They had significantly higher incidence of CS, cardiac arrest, and utilization of MCS devices. In-hospital mortality was higher in patients with rupture (41% vs. 7.40%, p < 0.001) which remained unchanged over the study period. Hospitalization cost and length of stay was also higher in them. MVP and revascularization led to better survival rates (27.9% vs. 60.6%, adjusted OR: 0.14; 95% CI: 0.10-0.19; p < 0.001). Despite significant advancement in the revascularization strategy, PMR/CTR after STEMI continues to portend poor prognosis with high inpatient mortality. Cardiogenic shock is a common presentation and is associated with significantly inpatient mortality. Future studies are needed determine the best strategies to improve outcomes in patients with STEMI with PMR/CTR and CS.

Tricuspid regurgitation in ischemic mitral regurgitation patients: prevalence, predictors for outcome and long-term follow-up

Background

Functional tricuspid regurgitation (FTR) is common in left-sided heart pathology involving the mitral valve. The incidence, clinical impact, risk factors, and natural history of FTR in the setting of ischemic mitral regurgitation (IMR) are less known.

Method

We conducted a cohort study based on data collected from January 2012 to December 2014. Patients diagnosed with IMR were eligible for the study. The median follow-up was 5 years. The primary outcome is defined as FTR developing at any stage.

Results

Among the 134 IMR patients eligible for the study, FTR was detected in 29.9% (N = 40, 20.0% mild, 62.5% moderate, and 17.5% severe). In the FTR group, the average age was 60.7 ± 9.2 years (25% females), the mean LV ejection fraction (LVEF) was 37.3 ± 6.45 [%], LA area 46.4 ± 8.06 (mm²), LV internal diastolic diameter (LVIDD) 59.6 ± 3.94 (mm), RV fractional area change 22.3 ± 4.36 (%), systolic pulmonary artery pressure (SPAP) 48.4 ± 9.45 (mmHg). Independent variables associated with FTR development were age ≥ 65y [OR 1.2], failed revascularization, LA area ≥ 42.5 (mm²) [OR 17.1], LVEF ≤ 24% [OR 32.5], MR of moderate and severe grade [OR 419.4], moderate RV dysfunction [OR 91.6] and pulmonary artery pressure of a moderate or severe grade [OR 33.6]. During follow-up, FTR progressed in 39 (97.5%) patients. Covariates independently associated with FTR progression were lower LVEF, RV dysfunction, and PHT of moderate severity. LA area and LVIDD were at the margin of statistical significance (p = 0.06 and p = 0.05, respectively).

Conclusion

In our cohort study, FTR development and progression due to IMR was a common finding. Elderly patients with ischemic MR following unsuccessful PCI are at higher risk. FTR development and severity are directly proportional to LV ejection fraction, to the extent of mitral regurgitation, and SPAP. FTR tends to deteriorate in the majority of patients over a mean of 5-y follow-up.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-01982-y.

Cardiogenic shock due to acute severe ischemic mitral regurgitation

The reduction in patients presenting with ST-elevation myocardial infarction (STEMI) during the COVID19 crisis could have resulted from fears about developing COVID-19 infection in hospital. Patients who delay presenting with STEMI are more likely to develop mechanical complications, including acute ischemic mitral regurgitation (MR). We present a 69-year-old women with an inferior STEMI and cardiogenic shock due to acute ischemic MR who delayed presenting to hospital due to the fear of COVID-19. Early identification of this mechanical complication using transthoracic echocardiography in the Emergency Department enabled the team to target her optimisation. Ultimately these patients require urgent surgery to repair the mitral valve and revascularize the myocardium but they are often too unwell to undergo surgery and even when it is feasible the outcomes are poor.

Fatal pulmonary hemorrhage due to severe mitral regurgitation during venoarterial extracorporeal membrane oxygenation

Pulmonary hemorrhage (PH) during venoarterial extracorporeal membrane oxygenation (VA-ECMO) has been primarily reported in pediatric patients. We report a case of fatal PH during VA-ECMO for cardiogenic shock after myocardial infarction (MI). PH, in this case, was secondary to a triad of aortic insufficiency, left ventricle distension, and severe laminar mitral regurgitation. This case scenario, previously unreported in adults, illustrates the need for the echocardiographic assessment of left-sided heart valves prior to VA-ECMO initiation after MI as well as management considerations for massive PH in this context.

Coronary Artery Disease: From Mechanism to Clinical Practice

In most developed countries, coronary artery disease (CAD), mostly caused by atherosclerosis of coronary arteries, is one of the primary causes of death. From 1990s to 2000s, mortality caused by acute MI declined up to 50%. The incidence of CAD is related with age, gender, economic, etc. Atherosclerosis contains some highly correlative processes such as lipid disturbances, thrombosis, inflammation, vascular smooth cell activation, remodeling, platelet activation, endothelial dysfunction, oxidative stress, altered matrix metabolism, and genetic factors. Risk factors of CAD exist among many individuals of the general population, which includes hypertension, lipids and lipoproteins metabolism disturbances, diabetes mellitus, chronic kidney disease, age, genders, lifestyle, cigarette smoking, diet, obesity, and family history. Angina pectoris is caused by myocardial ischemia in the main expression of pain in the chest or adjoining area, which is usually a result of exertion and related to myocardial function disorder. Typical angina pectoris would last for minutes with gradual exacerbation. Rest, sit, or stop walking are the usual preference for patients with angina, and reaching the maximum intensity in seconds is uncommon. Rest or nitroglycerin usage can relieve typical angina pectoris within minutes. So far, a widely accepted angina pectoris severity grading system included CCS (Canadian Cardiovascular Society) classification, Califf score, and Goldman scale. Patients with ST-segment elevated myocardial infarction (STEMI) may have different symptoms and signs of both severe angina pectoris and various complications. The combination of rising usage of sensitive MI biomarkers and precise imaging techniques, including electrocardiograph (ECG), computed tomography, and cardiac magnetic resonance imaging, made the new MI criteria necessary. Complications of acute myocardial infarction include left ventricular dysfunction, cardiogenic shock, structural complications, arrhythmia, recurrent chest discomfort, recurrent ischemia and infarction, pericardial effusion, pericarditis, post-myocardial infarction syndrome, venous thrombosis pulmonary embolism, left ventricular aneurysm, left ventricular thrombus, and arterial embolism.

Acute mitral regurgitation

The diagnosis of acute mitral regurgitation (MR) is often missed or delayed because the clinical presentation is substantially different from that in patients with chronic MR. Management of acute MR depends on the specific aetiology of valve dysfunction and there is a lack of consensus on the optimal therapeutic approach in many patients. In particular, management of secondary MR due to acute ischaemia is challenging because of unique mechanisms of valve incompetence compared with chronic ischaemic MR. Another clinical challenge is management of acute MR due to transient systolic anterior motion of the mitral valve in the acute phase of Takotsubo cardiomyopathy, which commonly resolves within a few weeks. Additionally, iatrogenic MR induced by intraventricular devices is a recently recognised aetiology of acute MR. Acute primary MR typically requires early surgical intervention, for example, with a flail leaflet or endocarditis, because of acute cardiovascular decompensation with an abrupt increase in left atrial pressure. In an emergency situation and high surgical risk, a percutaneous mitral valve edge-to-edge repair is an alternative therapeutic option. Firm diagnosis of the severity and aetiology of acute MR is necessary for proper decision making, including timing and types of surgical intervention.

Ovine Model of Ischemic Mitral Regurgitation

Ischemic mitral regurgitation (IMR) is a common complication of ischemic heart disease that doubles mortality after myocardial infarction and is a major driving factor increasing heart failure. IMR is caused by left ventricular (LV) remodeling which displaces the papillary muscles that tether the mitral valve leaflets and restrict their closure. IMR frequently recurs even after surgical treatment. Failed repair associates with lack of reduction or increase in LV remodeling, and increased heart failure and related readmissions. Understanding mechanistic and molecular mechanisms of IMR has largely attributed to the development of large animal models. Newly developed therapeutic interventions targeted to the primary causes can also be tested in these models. The sheep is one of the most suitable models for the development of IMR. In this chapter, we describe the protocols for inducing IMR in sheep using surgical ligation of obtuse marginal branches. After successful posterior myocardial infarction involving posterior papillary muscle, animals develop significant mitral regurgitation around 2 months after the surgery.

In-hospital mortality after acute STEMI in patients undergoing primary PCI

BACKGROUND

Acute myocardial infarction (AMI) is the main cause of global and in-hospital mortality in patients with cardiovascular diseases. We aimed to examine the association between the coronary artery involved and the in-hospital mortality in patients who underwent primary percutaneous coronary intervention (pPCI) after ST segment elevation myocardial infarction (STEMI).

METHODS

The in-hospital mortality of STEMI patients who underwent pPCI was assessed at the Department of Cardiology, Harzklinik Goslar, Germany, which has no access to immediate mechanical circulatory support (MCS), between 2013 and 2017.

RESULTS

We enrolled 312 STEMI patients, with a mean age of 67.1 ± 13.4 years, of whom 211 (68%) were male. In-hospital mortality was documented in 31 patients (10%). In-hospital mortality was associated with pre-hospital cardiopulmonary resuscitation (CPR; n = 39/12.5%), older age, lower systolic blood pressure, Killip class > 1, triple-vessel disease (each p < 0.0001), female gender (p = 0.0158), and with the localization of the treated culprit lesion in the left main coronary artery (LMCA; p = 0.0083) and in the ramus circumflexus (RCX; p = 0.0141).

CONCLUSION

In this monocentric cohort, all-cause in-hospital mortality of STEMI patients after pPCI was significantly higher in those patients with culprit lesions in the LMCA and in the RCX, which may prove to be a substantial novel risk factor for STEMI-related mortality. Increasing age and female gender may be interdependent risk factors for mortality in this patient population. Furthermore, our data highlight the importance of the availability of MCS options in pPCI centers for patients after CPR.

Impella percutaneous left ventricular assist device for severe acute ischaemic mitral regurgitation as a bridge to surgery

Ischaemic papillary muscle rupture causing acute severe mitral regurgitation (MR) has a dramatic presentation and a very high mortality. Emergent surgical repair improves outcomes, which necessitates robust preoperative stabilisation. Here we discuss a patient with cardiogenic shock with an acute severe MR that was deemed very high risk for emergent valve replacement due to haemodynamic instability and respiratory failure. A percutaneous left ventricular assist device Impella 2.5 (Abiomed, Danvers, MA) drastically improved clinical status, and the patient underwent a successful surgical mitral valve replacement soon after placement of the temporary assist device. Our case highlights that percutaneous ventricular assist devices may help to stabilise patients with severe acute ischaemic MR, and it can serve as a bridge to surgery in high risk patients.

Percutaneous and minimally invasive approaches to mitral valve repair for severe mitral regurgitation-new devices and emerging outcomes

Mitral valve disease is common in the United States and around the world, and if left untreated, increases cardiovascular morbidity and mortality. Mitral valve repair is technically more demanding than mitral valve replacement. Mitral valve repair should be considered the first line of treatment for mitral regurgitation in younger patients, mitral valve prolapse, annular dilatation, and with structural damage to the valve. Several minimally invasive percutaneous treatment options for mitral valve repair are available that are not restricted to conventional surgical approaches, and may be better received by patients. A useful classification system of these approaches proposed by Chiam and Ruiz is based on anatomic targets and device action upon the leaflets, annulus, chordae, and left ventricle. Future directions of minimally invasive techniques will include improving the safety profile through patient selection and risk stratification, improvement of current imaging and techniques, and multidisciplinary education.

Prognostic importance of mitral regurgitation complicated by acute myocardial infarction during a 5-year follow-up period in the drug-eluting stent era

BACKGROUND

Mitral regurgitation (MR) is a frequent complication of left-ventricular dysfunction, with an incidence ranging from 13 to 59% after acute myocardial infarction (AMI), which is associated with poor clinical outcome. The aim of this study was to assess the clinical and angiographic characteristics associated with MR, the incidence and predictors of MR, and the outcomes of MR after AMI in those who were successfully treated with primary percutaneous coronary intervention (PCI) using a drug-eluting stent.

METHODS

We analyzed a multicenter all-comer AMI registry and identified 4748 patients between January 2004 and December 2009. Of these, 1894 patients were treated with PCI using a drug-eluting stent and had MR. The association between MR and the composite of major adverse cardiac and cerebrovascular events (MACCE; all-cause death, recurrent nonfatal myocardial infarction, stroke, and any revascularization) was examined.

RESULTS

Patients with MR after the index PCI showed significantly higher cumulative incidence of MACCE compared with no-MR patients over the 5-year survival period (P=0.002). When the MR groups were compared on the basis of the severity of MR, ranging from mild to severe grades, a higher grade of MR was found to be associated with a higher incidence of MACCE (P<0.001). Multivariate Cox proportional hazard analysis revealed that no reflow, left-ventricular ejection fraction less than 50%, and anemia, in addition to MR, were consistently associated with increased all-cause death during the 5-year period (adjusted hazard ratio 1.408, 95% confidence interval 1.052-1.884, P=0.021).

CONCLUSION

MR after AMI in patients successfully treated with primary PCI was associated with poor long-term outcome regardless of ST-segment elevation at diagnosis during the drug-eluting stent era.

Physiological Implications of Myocardial Scar Structure

Once myocardium dies during a heart attack, it is replaced by scar tissue over the course of several weeks. The size, location, composition, structure, and mechanical properties of the healing scar are all critical determinants of the fate of patients who survive the initial infarction. While the central importance of scar structure in determining pump function and remodeling has long been recognized, it has proven remarkably difficult to design therapies that improve heart function or limit remodeling by modifying scar structure. Many exciting new therapies are under development, but predicting their long-term effects requires a detailed understanding of how infarct scar forms, how its properties impact left ventricular function and remodeling, and how changes in scar structure and properties feed back to affect not only heart mechanics but also electrical conduction, reflex hemodynamic compensations, and the ongoing process of scar formation itself. In this article, we outline the scar formation process following a myocardial infarction, discuss interpretation of standard measures of heart function in the setting of a healing infarct, then present implications of infarct scar geometry and structure for both mechanical and electrical function of the heart and summarize experiences to date with therapeutic interventions that aim to modify scar geometry and structure. One important conclusion that emerges from the studies reviewed here is that computational modeling is an essential tool for integrating the wealth of information required to understand this complex system and predict the impact of novel therapies on scar healing, heart function, and remodeling following myocardial infarction.

Surgical revascularization is associated with maximal survival in patients with ischemic mitral regurgitation: a 20-year experience

BACKGROUND

The optimal treatment for ischemic mitral regurgitation remains actively debated. Our objective was to evaluate the relationship between ischemic mitral regurgitation treatment strategy and survival.

METHODS AND RESULTS

We retrospectively reviewed patients at our institution diagnosed with significant coronary artery disease and moderate or severe ischemic mitral regurgitation from 1990 to 2009, categorized by medical treatment alone, percutaneous coronary intervention, coronary artery bypass grafting (CABG), or CABG plus mitral valve repair or replacement. Kaplan-Meier methods and multivariable Cox proportional hazards analyses were performed to assess the relationship between treatment strategy and survival, with the use of propensity scores to account for nonrandom treatment assignment. A total of 4989 patients were included: medical treatment alone=36%, percutaneous coronary intervention=26%, CABG=33%, and CABG plus mitral valve repair or replacement=5%. Median follow-up was 5.37 years. Compared with medical treatment alone, significantly lower mortality was observed in patients treated with percutaneous coronary intervention (adjusted hazard ratio, 0.83; 95% confidence interval, 0.76-0.92; P=0.0002), CABG (adjusted hazard ratio, 0.56; 95% confidence interval, 0.51-0.62; P<0.0001), and CABG plus mitral valve repair or replacement (adjusted hazard ratio, 0.69; 95% confidence interval, 0.57-0.82; P<0.0001). There was no significant difference in these results based on mitral regurgitation severity.

CONCLUSIONS

Patients with significant coronary artery disease and moderate or severe ischemic mitral regurgitation undergoing CABG alone demonstrated the lowest risk of death. CABG with or without mitral valve surgery was associated with lower mortality than either percutaneous coronary intervention or medical treatment alone.

Comprehensive annular and subvalvular repair of chronic ischemic mitral regurgitation improves long-term results with the least ventricular remodeling

BACKGROUND

Undersized ring annuloplasty for ischemic mitral regurgitation (MR) is associated with variable results and >30% MR recurrence. We tested whether subvalvular repair by severing second-order mitral chordae can improve annuloplasty by reducing papillary muscle tethering.

METHODS AND RESULTS

Posterolateral myocardial infarction known to produce chronic remodeling and MR was created in 28 sheep. At 3 months, sheep were randomized to sham surgery versus isolated undersized annuloplasty versus isolated bileaflet chordal cutting versus the combined therapy (n=7 each). At baseline, chronic myocardial infarction (3 months), and euthanasia (6.6 months), we measured left ventricular (LV) volumes and ejection fraction, wall motion score index, MR regurgitation fraction and vena contracta, mitral annulus area, and posterior leaflet restriction angle (posterior leaflet to mitral annulus area) by 2-dimensional and 3-dimensional echocardiography. All groups were comparable at baseline and chronic myocardial infarction, with mild to moderate MR (MR vena contracta, 4.6±0.1 mm; MR regurgitation fraction, 24.2±2.9%) and mitral annulus dilatation (P<0.01). At euthanasia, MR progressed to moderate to severe in controls but decreased to trace with ring plus chordal cutting versus trace to mild with chordal cutting alone versus mild to moderate with ring alone (MR vena contracta, 5.9±1.1 mm in controls, 0.5±0.08 with both, 1.0±0.3 with chordal cutting alone, 2.0±0.4 with ring alone; P<0.01). In addition, LV end-systolic volume increased by 108% in controls versus 28% with ring plus chordal cutting, less than with each intervention alone (P<0.01). In multivariate analysis, LV end-systolic volume and mitral annulus area most strongly predicted MR (r(2)=0.82, P<0.01).

CONCLUSIONS

Comprehensive annular and subvalvular repair improves long-term reduction of both chronic ischemic MR and LV remodeling without decreasing global or segmental LV function at follow-up.

Mitral stenosis after IMR ETlogix ring annuloplasty for ischemic regurgitation

Objectives: Ring annuloplasty combined with coronary artery bypass grafting is the standard approach for treatment of patients with ischemic mitral regurgitation. We evaluated mitral valve hemodynamic performance and recurrence of mitral regurgitation after ring annuloplasty.

Patients and methods: 40 consecutive patients (mean age, 70 ± 8 years) with chronic ischemic mitral regurgitation grade ≥2+ received annuloplasty with an IMR ETlogix ring. During follow-up (25.9 ± 15.5 months), 84% of surviving patients underwent exercise stress echocardiography to assess recurrence of mitral regurgitation and differences between rest and exercise mitral valve hemodynamic performance.

Results: Hospital mortality was 10%. During follow-up, we found no significant differences between left ventricular ejection fraction or end-diastolic and end-systolic diameters pre- and postoperatively (41% vs. 45%, 59 vs. 56 mm, and 49 vs. 46 mm, respectively), but there was a significant increase in mitral mean gradient with exercise (3.3 ± 1.2 vs. 7.8 ± 4 mm Hg, p < 0.001). Two patients had mitral regurgitation ≥grade III–IV.

Conclusions: Mitral annuloplasty with the IMR ETlogix ring provides effective correction of chronic ischemic mitral regurgitation, but this technique may induce functional mitral stenosis.

Unilateral pulmonary edema: a rare initial presentation of cardiogenic shock due to acute myocardial infarction

Cardiogenic unilateral pulmonary edema (UPE) is a rare clinical entity that is often misdiagnosed at first. Most cases of cardiogenic UPE occur in the right upper lobe and are caused by severe mitral regurgitation (MR). We present an unusual case of right-sided UPE in a patient with cardiogenic shock due to acute myocardial infarction (AMI) without severe MR. The patient was successfully treated by percutaneous coronary intervention and medical therapy for heart failure. Follow-up chest Radiography showed complete resolution of the UPE. This case reminds us that AMI can present as UPE even in patients without severe MR or any preexisting pulmonary disease affecting the vasculature or parenchyma of the lung.

Evaluation of the performance of echocardiography in acute coronary syndrome patients during their stay in coronary units

OBJECTIVES

To evaluate the frequency and the factors associated with performance of echocardiography in acute coronary syndrome (ACS) patients during their stay in intensive care units or coronary care units (ICU/CCU).

METHODS

Retrospective cohort study including all patients diagnosed with acute coronary syndrome-unstable angina (UA), acute myocardial infarction (AMI)-included in the 'ARIAM' Spanish multi-centre register. The study period was from June 1996 to December 2005. The follow-up period is limited to the time of stay in the Intensive Care Units or Coronary Care Units (ICUs/CCUs). A univariate analysis was carried out on the patients with UA and AMI according to whether or not echocardiograms were performed during their stay in ICU/CCU. In addition the data was evaluated for any temporal variation in the performance of echocardiography, and two multivariate analyses were carried out to evaluate the factors associated with performance of echocardiography in UA and AMI patients.

RESULTS

The study period included 45,688 AMI patients and 17,277 UA patients. Echocardiograms were performed in 26.87% AMI patients and 16.75% UA patients. In total, 15,172 echocardiograms were performed in ACS patients (23.6%). The multivariate analysis demonstrated that the variables associated with the performance of echocardiography in UA were: Killip and Kimball class, cigarette smoking, family history of cardiovascular events, cardiogenic shock, uncontrolled angina, mechanical ventilation and treatment with ACE inhibitors, while the presence of previous AMI was associated with fewer echocardiograms being performed. In AMI, the multivariate analysis showed the following variables to be associated with the performance of echocardiography: Killip and Kimball class, Q-AMI, right heart failure, the need for insertion of Swan-Ganz catheter, cardiogenic shock, high-degree AV block and the administration of ACE inhibitors, while age was associated with fewer being performed. Over the 10 years of the study period, there was a discrete but significant increase in the use of echocardiography in patients in ICU/CCU.

CONCLUSIONS

Echocardiography is not commonly used in ACS patients while in ICU/CCU. UA and AMI patients who did have echocardiograms during their stay in ICU/CCU were chiefly those presenting heart failure and major complications, and represent a subpopulation with poor prognosis. The performance of echocardiography in ACS patients increased slightly over the length of their stay in ICU/CCU.

Assessing functional mitral regurgitation with exercise echocardiography: rationale and clinical applications

Secondary or functional mitral regurgitation (FMR) represents an increasing feature of mitral valve disease characterized by abnormal function of anatomically normal leaflets in the context of the impaired function of remodelled left ventricles. The anatomic and pathophysiological basis of FMR are briefly analyzed; in addition, the role of exercise echocardiography for the assessment of FMR is discussed in view of its relevance to clinical practice.

Risk of heart failure due to a combination of mild mitral regurgitation and impaired distensibility of the left ventricle in patients with old myocardial infarction

BACKGROUND

Ischemic mitral regurgitation (MR) is a serious complication after myocardial infarction, and the incidence of heart failure (HF) increases as the severity of MR increases. However, little is known about the relationship between mild MR and HF in the patients with old myocardial infarction (OMI) and a normal ejection fraction (EF).

HYPOTHESIS

We hypothesized that a combination of mild MR and impaired distensibility of the left ventricle may increase the risk of diastolic HF in the patients with OMI and a normal EF.

METHODS

The relationship between HF and mild MR was retrospectively investigated in 62 patients with OMI and EF of > 50% on echocardiography.

RESULTS

Of the 62 patients, 47 (76%) did not have HF and 15 (24%) had HF. There was a significant difference in the incidence of mild MR between the patients with and without HF (p < 0.0001): of the 47 patients without HF, mild MR was detected in 19, but all 15 patients with HF had mild MR. However, there were no significant differences in age, gender, infarct sites, diseased coronary vessels, peak CK level, and observation period between the 2 groups. An increased E-wave and the ratio of the E-wave to the A-wave (E/A), a reduction of the E-wave deceleration time, and an increased brain natriuretic peptide (BNP) level were significantly noted in HF patients with mild MR compared with patients without HF.

CONCLUSIONS

Even a mild MR may cause diastolic HF in patients with impaired distensibility of the left ventricle due to ischemic heart disease.

Functional mitral regurgitation after a first non-ST-segment elevation acute coronary syndrome: contribution to congestive heart failure

AIMS

Functional mitral regurgitation (MR) is a frequent complication after the acute phase of a myocardial infarction and plays an important role in the development of congestive heart failure (CHF) after a Q-wave myocardial infarction. Nevertheless, until now, the relevance of functional MR after a non-ST-segment elevation acute coronary syndrome (NSTSEACS) has been poorly addressed. Our aim was to assess the relationship between the presence or absence and the severity of functional MR after a first NSTSEACS and the development of CHF.

METHODS AND RESULTS

Two hundred and seventy-nine patients discharged from hospital in NYHA functional classes I and II (71.7% men; mean age 66.3 +/- 13.2 years) after a first NSTSEACS were studied. Every patient underwent an echocardiographic study during the first week after the index NSTSEACS and were clinically followed-up. MR was detected in 40.1% patients. Patients were followed-up for a median time of 418 days (inter-quartile range: 295-561). Six patients (3.6%) in the group without MR and 15 patients (13.4%) in the group with MR required hospitalization due to CHF during follow-up. Only MR was found as an independent predictor of CHF development (HR = 1.8; 95% CI = 1.1-3.1; P = 0.02) and CHF development or cardiac death (HR = 2.1; 95% CI = 1.3-3.3; P = 0.01) in the long-term follow-up multivariable Cox regression analysis.

CONCLUSION

There is an increased risk for subsequent CHF in patients with MR after a first NSTSEACS. The risk of CHF is closely related to the MR presence and severity. Thus, the detection of MR by means of Doppler echocardiography after a first episode of NSTSEACS is crucial.

Mitral Valve Tenting Index for Assessment of Subvalvular Remodeling

BACKGROUND

Ischemic mitral regurgitation results from a variable combination of annular dilatation and remodeling of the subvalvular apparatus. Current surgical techniques effectively treat annular dilatation, but methods for addressing subvalvular remodeling have not been standardized. An effective technique for determining the extent of subvalvular remodeling could improve surgical results by identifying patients who are unlikely to benefit from annuloplasty alone.

METHODS

A well-characterized ovine model of ischemic mitral regurgitation was used. Real-time three-dimensional echocardiography was performed on each animal at baseline and at 1 hour and 8 weeks after infarction. Multiple valvular geometric measurements were calculated at each time point.

RESULTS

Immediate and long-term changes in mitral valvular geometry were observed. Annular height-to-commissural width ratio decreased from 20.0% +/- 1.6% to 11.2% +/- 0.9% 1 hour after infarction (p < 0.001) and to 9.4% +/- 0.4% 8 weeks after infarction (p < 0.001), whereas mitral annular area increased from 8.1 +/- 0.3 cm2 to 9.2 +/- 0.4 cm2 (p < 0.05) and then to 10.5 +/- 0.6 cm2 (p < 0.05). Maximum mitral valve tenting area increased from 49.7 +/- 5.1 mm2 to 58.6 +/- 4.2 mm2 (p < 0.05) and then to 106.4 +/- 3.9 mm2 (p < 0.001), whereas mitral valve tenting volume increased from 679.0 +/- 75.5 mm3 to 828.6 +/- 102.4 mm3 (p = 0.050) and then to 1530.5 +/- 97.8 mm3 (p < 0.001). The mitral valve tenting index increased from 0.83 +/- 0.08 mm to 0.88 +/- 0.08 mm (p > 0.05) and then to 1.46 +/- 0.08 mm (p < 0.001).

CONCLUSIONS

We have described a technique that uses real-time three-dimensional echocardiography to perform a comprehensive assessment of leaflet tethering on the entire mitral valve. Our methodology is not influenced by viewing plane selection, regional tenting asymmetry, or annular dilatation and therefore represents a potentially useful, clinically relevant, and consistent measure of subvalvular remodeling.

Complications of myocardial infarction

Echocardiography is a most useful bedside tool to help in the diagnosis and management of critically ill patients after acute myocardial infarction. In most instances, the mechanism of unexplained shock will be elucidated. Transesophageal echocardiography can further delineate the mechanical complications of myocardial infarction when the transthoracic echocardiogram may not be adequate. This article will focus on the mechanical complications of myocardial infarction in patients who most often present with cardiogenic shock or acute pulmonary edema. Each clinical entity is discussed, and illustrative echocardiograms are provided.

Ischemic mitral regurgitation

Ischemic mitral regurgitation is the regurgitation seen with structurally normal valve leaflets that occurs in approximately 20% of patients after myocardial infarction and 56% of patients with congestive heart failure caused by ischemic or nonischemic cardiomyopathy. The initiating event is an ischemic insult that results in remodeling of the left ventricle toward a more spherical shape and new wall motion abnormalities. These changes lead to annular dilation and subvalvular distortion that prevent the mitral leaflets from coapting and closing completely during the contraction phase. Treatment options include coronary revascularization, ring annuloplasty, valve repair and replacement, or left ventricle reconstruction by way of localized reshaping or resection. Pharmacotherapy, aimed at raising left ventricular pressure without increasing tethering or left ventricular volume, is included in the treatment options for improving ischemic mitral regurgitation.

Mitral regurgitation after myocardial infarction: a review

Mitral regurgitation after myocardial infarction is the result of multifactorial processes involving local and global left ventricular remodeling. The prevalence of mitral regurgitation varies from 11% to 59%. Published studies differ greatly in design, inclusion criteria, duration of follow-up, and technique of mitral regurgitation assessment. However, they consistently indicate that mitral regurgitation after myocardial infarction carries an adverse prognosis with increased risk of death and heart failure independently of previously known indicators of risk after myocardial infarction. Mitral regurgitation is often clinically silent; therefore, it should be systematically evaluated by echocardiography. Standard color Doppler imaging is a highly sensitive method to detect even mild degrees of ischemic mitral regurgitation. One unique advantage of echocardiography is that it accurately quantifies the severity of mitral regurgitation by measuring the effective regurgitant orifice area and the regurgitant volume using Doppler methodology. Therefore, the evaluation should include precise quantification of the degree of mitral regurgitation to best appraise the ensuing risk. Current medical options rely chiefly on angiotensin converting enzyme-inhibitors and beta-blocker therapy, and surgical approaches offer future promise. Both categories of therapeutic approaches should be evaluated by randomized controlled trials.

Accelerated LV remodeling after myocardial infarction in TIMP-1-deficient mice: effects of exogenous MMP inhibition

Alterations in matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) have been implicated in adverse left ventricular (LV) remodeling after myocardial infarction (MI). However, the direct mechanistic role of TIMPs in the post-MI remodeling process has not been completely established. The goal of this project was to define the effects of altering endogenous MMP inhibitory control through combined genetic and pharmacological approaches on post-MI remodeling in mice. This study examined the effects of MMP inhibition (MMPi) with PD-166793 (30 mg.kg(-1).day(-1)) on LV geometry and function (conductance volumetry) after MI in wild-type (WT) mice and mice deficient in the TIMP-1 gene [TIMP-1 knockout (TIMP1-KO)]. At 3 days after MI (coronary ligation), mice were randomized into four groups: WT-MI/MMPi (n = 10), TIMP1-KO-MI/MMPi (n = 10), WT-MI (n = 22), and TIMP1-KO-MI (n = 23). LV end-diastolic volume (EDV) and ejection fraction were determined 14 days after MI. Age-matched WT (n = 20) and TIMP1-KO (n = 28) mice served as reference controls. LVEDV was similar under control conditions in WT and TIMP1-KO mice (36 +/- 2 and 40 +/- 2 microl, respectively) but was greater in TIMP1-KO-MI than in WT-MI mice (48 +/- 2 vs. 61 +/- 5 microl, P < 0.05). LVEDV was reduced from MI-only values in WT-MI/MMPi and TIMP1-KO-MI/MMPi mice (42 +/- 2 and 36 +/- 2 microl, respectively, P < 0.05) but was reduced to the greatest degree in TIMP1-KO mice (P < 0.05). LV ejection fraction was reduced in both groups after MI and increased in TIMP1-KO-MI/MMPi, but not in WT-MI/MMPi, mice. These unique results demonstrated that myocardial TIMP-1 plays a regulatory role in post-MI remodeling and that the accelerated myocardial remodeling induced by TIMP-1 gene deletion can be pharmacologically "rescued" by MMP inhibition. These results define the importance of local endogenous control of MMP activity with respect to regulating LV structure and function after MI.

[Mechanical complications of acute myocardial infarction]

Rupture of the left ventricular myocardium during the course of an acute myocardial infarction may affect the free wall, the interventricular septum, or the papillary muscles. When a rupture occurs, it is referred to as a mechanical complication of acute myocardial infarction. All mechanical complications may lead to cardiogenic shock. However, the location of the rupture can often be suspected clinically. To confirm the diagnosis, echocardiography must be performed. Since the advent of thrombolytic therapy and percutaneous coronary intervention, the incidence of mechanical complications has declined. Even though mortality remains high, their recognition is important since survivors may have an excellent long-term prognosis. The cases convey two main messages: 1) Mechanical complications must be carefully searched for in any patient with an acute coronary syndrome and signs of cardiogenic shock and/or a systolic murmur. 2) Aggressive and timely medical and surgical treatment should be provided even though in a substantial proportion of these patients prognosis may be dismal.

Transcriptional coregulator SNW/SKIP: the concealed tie of dissimilar pathways

Eukaryotic gene expression requires that all the steps of messenger RNA production are regulated in concert to integrate the diverse inputs cells receive. We discuss the functioning of SNW/SKIP, an essential spliceosomal component and transcriptional coregulator, which may provide regulatory coupling of transcription initiation and splicing. SNW/SKIP potentiates the activity of important transcription factors, such as vitamin D receptor, CBF1 (RBP-Jkappa), Smad2/3, and MyoD. It synergizes with Ski in overcoming pRb-mediated cell cycle arrest, and it is targeted by the viral transactivators EBNA2 and E7. SNW/SKIP may aid in conformational transition of the gene expression machine through its avidity to nuclear matrix fractions or by recruiting foldases such as the prolyl isomerase PPIL1. The extensive list of SNW/SKIP partners, its unique primary structure, conserved from yeast to humans, and its essential character suggest a distinct function of general importance.