Renin-angiotensin system and cardiac rupture after myocardial infarction

Ventricular silent rupture leading to sudden death: Navigating diagnostic challenges in a resource-constraint setting

Key Clinical Message

Ventricular myocardial rupture is a rare complication of myocardial infarction. It occurs within hours to weeks after an infarction. Mortality is high. Antemortem diagnosis is a challenge in low-resource settings, leading to potential misdiagnosis.

Abstract

Left ventricular myocardial rupture is a potentially fatal yet common complication in acute myocardial infarction patients. Rupture can occur as early as hours after an infarction. However, rupture may also occur later in the first week in the setting of myocardial necrosis and neutrophilic infiltration. Patients may survive several days to weeks before rupture occurs, and cardiac tamponade may present subacutely with a slow or repetitive clinical course. Sudden death can be attributed to ventricular rupture, more commonly during this time frame. Myocardial rupture can also occur as a result of trauma, infections, or cancer. Mortality is exceedingly high if surgical intervention is delayed. In most patients, myocardial rupture manifests as a catastrophic event within days of a first, small, uncomplicated acute myocardial infarction. Acute onset of shortness of breath, chest pain, shock, diaphoresis, unexplained emesis, cool and clammy skin, and syncope may herald the onset of ventricular septal rupture after acute myocardial infarction. Sudden death from myocardial rupture during acute myocardial infarction in patients with no apparent previous symptoms of myocardial ischemia represents a challenge for medical examiners, law enforcement officers, and society as a whole. An autopsy is critical for establishing the cause of death. We present the case of a 54-year-old male whose body was found beside the road after a trivial quarrel a day before. Further medical information about the deceased was not available. The preliminary cause of death was presumed to be traumatic. No evidence of trauma was seen during the autopsy. Massive pericardial blood collection compressing the heart and concealed left ventricular myocardial rupture were noted. Histopathological examination of the heart demonstrated myocardial infarction with a tear associated with bleeding that was contained in the pericardial sac. We ruled cardiac tamponade as the cause of death due to an infarcted myocardial rupture. Antemortem diagnosis of myocardial rupture can be challenging in low-resource settings, leading to potential misdiagnosis and negative impacts such as community conflicts.

Prognostic impact of monocyte-to-lymphocyte ratio in coronary heart disease: a systematic review and meta-analysis

OBJECTIVE

Inflammatory biomarkers are novel tools to assess the prognosis of different cardiovascular diseases. We evaluated the impact of the monocyte-to-lymphocyte ratio (MLR) on clinical outcomes in patients with coronary heart disease (CHD).

METHODS

We systematically screened English-language articles in PubMed, Scopus, and Web of Science to 31 August 2022. Relevant articles reporting the MLR and its association with clinical outcomes (major adverse cardiovascular events (MACE), coronary artery disease (CAD) severity, mortality, cardiac rupture, subclinical CAD, acute coronary syndrome (ACS) prediction, thin-cap fibroatheroma, no-reflow phenomenon, MLR-related differences in percutaneous coronary intervention, heart failure hospitalization, and depression) in patients with CHD were collected for further analysis.

RESULTS

Nineteen articles were selected. The mean MLR was 0.34. A higher MLR was significantly associated with an increased risk of MACE among patients with CHD. The MLR was an independent predictor of MACE in patients with ACS. No significant association was found for CAD severity. A complementary analysis was not performed because of few studies focusing on the other predefined endpoints.

CONCLUSIONS

The MLR is a simple and widely available tool to predict MACE in patients with CHD. This biomarker can be utilized in emergency settings to prioritize high-risk patients and optimize therapeutic interventions.

Association of Blood Urea Nitrogen with Cardiovascular Diseases and All-Cause Mortality in USA Adults: Results from NHANES 1999-2006

In the general population, there is little evidence of a link between blood urea nitrogen (BUN) and long-term mortality. The goal of this study was to explore whether higher BUN concentration is a predictor of cardiovascular disease (CVD) and all-cause mortality. From 1999 to 2006, the National Health and Nutrition Examination Survey (NHANES) included 17,719 adult individuals. Death outcomes were ascertained by linkage to the database records through 31 December 2015. The Cox proportional hazard regression model was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for CVD and all-cause mortality in individuals. We also performed stratified analyses based on age, gender, drinking, smoking, history of hypertension and diabetes. During a mean follow-up 11.65 years, a total of 3628 deaths were documented, of which 859 were due to CVD. Participants with higher BUN had a higher risk of CVD and all-cause death compared to those with lower BUN. After multifactor adjustment for demographics, major lifestyle factors, and hypertension and diabetes history, higher BUN levels compared with lower levels were significantly associated with higher risk of CVD (HR: 1.48 [1.08, 2.02], P-trend < 0.001) and all-cause mortality (HR: 1.48 [1.28, 1.72], P-trend < 0.001). In subgroup analyses, we found that the trend in the association of BUN with the risk of death remained strong in female subjects. Greater BUN levels were linked to higher CVD and all-cause mortality in the NHANES of American adults. The importance of BUN in predicting death is supported by our research.

Blood urea nitrogen/albumin ratio on admission predicts mortality in patients with non ST segment elevation myocardial infarction

The aim of this study is to reveal the predictive power of biomarkers and SYNTAX (SX) score for short-term mortality in patients diagnosed with non-ST-segment elevation myocardial infarction (NSTEMI) in the emergency department. This is prospective observational cohort study. Demographic characteristics of the patients, laboratory parameters on admission, left ventricular ejection fraction (LVEF) percentages, affected vessels in angiography (CAG) and the treatment strategy [medical therapy, percutaneous transluminal coronary angioplasty (PTCA), coronary angio by-pass graft] and SX scores were recorded on the data collection form. ROC curve was used to investigate the predictivity of blood urea nitrogen/albumin ratio (BAR), procalcitonin, C-reactive protein (CRP), high sensitivity cardiac troponin I (Hs-cTnI), CRP to serum albumin ratio (CAR), neutrophil to lymphocyte ratio (NLR) and SX scores in mortality. Multivariate analysis of biomarkers and SX score was performed to estimate the patients' 30-day mortality. Of the 415 patients were included in the study. ROC analysis of BAR, CAR, CRP, Procalcitonin, Hs-cTnI, NLR and SX score to predict mortality was statistically significant. BAR (OR: 1.280, 95% CI: 1.113-1.472, p = .001) and SX score (OR: 1.071, 95% CI: 1.018-1.126, p = .007) were found to be independent predictors of 30 days mortality. LVEF reduction, SX score, the number of affected vessels and the frequency of LMCA lesions increase were found to be statistically significant in patients with BAR ≥4.8. BAR, which can be calculated easily and quickly on admission to the emergency department and in clinical practice, may be used to predict mortality in patients with NSTEMI.

Endothelin and the Cardiovascular System: The Long Journey and Where We Are Going

Simple Summary

In this review, we describe the basic functions of endothelin and related molecules, including their receptors and enzymes. Furthermore, we discuss the important role of endothelin in several cardiovascular diseases, the relevant clinical evidence for targeting the endothelin pathway, and the scope of endothelin-targeting treatments in the future. We highlight the present uses of endothelin receptor antagonists and the advancements in the development of future treatment options, thereby providing an overview of endothelin research over the years and its future scope.

Abstract

Endothelin was first discovered more than 30 years ago as a potent vasoconstrictor. In subsequent years, three isoforms, two canonical receptors, and two converting enzymes were identified, and their basic functions were elucidated by numerous preclinical and clinical studies. Over the years, the endothelin system has been found to be critical in the pathogenesis of several cardiovascular diseases, including hypertension, pulmonary arterial hypertension, heart failure, and coronary artery disease. In this review, we summarize the current knowledge on endothelin and its role in cardiovascular diseases. Furthermore, we discuss how endothelin-targeting therapies, such as endothelin receptor antagonists, have been employed to treat cardiovascular diseases with varying degrees of success. Lastly, we provide a glimpse of what could be in store for endothelin-targeting treatment options for cardiovascular diseases in the future.

Predictive Value of Blood Urea Nitrogen to Albumin Ratio in Long-Term Mortality in Intensive Care Unit Patients with Acute Myocardial Infarction: A Propensity Score Matching Analysis

Background

Blood urea nitrogen to albumin ratio (BAR) has been implicated in predicting outcomes of various inflammatory-related diseases. However, the predictive value of BAR in long-term mortality in patients with acute myocardial infarction (AMI) has not yet been evaluated.

Methods

In this retrospective cohort study, the patients were recruited from the Medical Information Mart for Intensive Care III (MIMIC III) database and categorized into two groups by a cutoff value of BAR. Kaplan–Meier (K-M) analysis and Cox proportional hazard model were performed to determine the predictive value of BAR in long-term mortality following AMI. In order to adjust the baseline differences, a 1:1 propensity score matching (PSM) was carried out and the results were further validated.

Results

A total of 1827 eligible patients were enrolled. The optimal cutoff value of BAR for four-year mortality was 7.83 mg/g. Patients in the high BAR group tended to have a longer intensive care unit (ICU) stay and a higher rate of one-, two-, three- and four-year mortality (all p<0.001) compared with those in the low BAR group. K-M curves indicated a significant difference in four-year survival (p<0.001) between low and high BAR groups. The Cox proportional hazards model showed that higher BAR (>7.83) was independently associated with increased four-year mortality in the entire cohort, with a hazard ratio (HR) of 1.478 [95% CI (1.254–1.740), p<0.001]. After PSM, the baseline characteristics of 312 pairs of patients in the high and low BAR groups were well balanced, and similar results were observed in K-M curve (p=0.003).

Conclusion

A higher BAR (>7.83) was associated with four-year mortality in patients with AMI. As an easily available biomarker, BAR can predict the long-term mortality in AMI patients independently.

The Predictive Value of the Monocyte-to-Lymphocyte Ratio and Monocyte-to-Haematocrit Ratio for Cardiac Rupture Patients with Acute Myocardial Infarction: A Propensity Score Matching Analysis

Background

Cardiac rupture (CR) is a serious complication of acute myocardial infarction (AMI). We aimed to explore the predictive value of blood cell parameters for identifying CR in patients with AMI using the introduction of propensity score matching (PSM).

Methods

This retrospective study enrolled patients who were diagnosed with AMI from January 2013 to May 2020. A total of 109 patients with CR were included, and 327 hospitalized non-CR patients were randomly selected at a 1:3 ratio. Based on the 1:1 nearest neighbour matching method by using SPSS, the covariances of the two groups were balanced. After PSM, the independent risk factors for CR were selected by using multivariate logistic regression analysis, and receiver operating characteristic (ROC) curve analysis was applied to evaluate the predictive value of blood cell parameters for CR. Ninety cases were matched successfully in each of the two groups.

Results

Among the 180 patients with AMI after PSM, the results of multivariate logistic regression analysis showed that the monocyte-to-lymphocyte ratio (MLR) (OR = 3.57, 95% CI: 1.28–9.97, P = 0.015) and monocyte-to-haematocrit ratio (MHR) (OR = 1.80, 95% CI: 1.02–3.20, P = 0.043) were independently related to the risk of CR. Additionally, the MLR (area under the curve (AUC): 0.74) and MHR (AUC: 0.73) were useful for distinguishing CR patients after PSM. To differentiate CR patients from the control subjects, the optimal cut-offs of the MLR and MHR were 0.61 (63% sensitivity and 80% specificity) and 2.06 (57% sensitivity and 81% specificity), respectively.

Conclusion

The blood cell parameters MLR and MHR were independently correlated with CR. Additional, the MLR and MHR were useful to predict CR in patients with AMI.

Neutrophil percentage-to-albumin ratio and monocyte-to-lymphocyte ratio as predictors of free-wall rupture in patients with acute myocardial infarction

Backgrounds

Free‐wall rupture (FWR) has a high mortality rate. We aimed to find sensitive predictive indicators to identify high‐risk FWR patients by exploring the predictive values of neutrophil percentage‐to‐albumin ratio (NPAR) and monocyte‐to‐lymphocyte ratio (MLR) on patients with acute myocardial infarction (AMI).

Methods

76 FWR patients with AMI were collected, and then 228 non‐CR patients with AMI were randomly selected (1:3 ratio) in this retrospective study. The independent influencing factors of FWR were evaluated by univariate and multivariate logistic regression analysis. The receiver‐operating characteristic (ROC) curve analysis was applied to evaluate the predictive value of NPAR and MLR for FWR.

Results

According to the results of multivariate logistic regression analysis, emergency percutaneous coronary intervention (PCI) (OR = 0.27, 95% CI: 0.094–0.751, p = 0.012), angiotensin‐converting enzyme inhibitor (ACEI)/angiotensin receptor blocker (ARB) treatment (OR = 0.17, 95% CI: 0.044–0.659, p = 0.010), NPAR (OR = 2.69, 95% CI: 1.031–7.044, p = 0.043), and MLR (OR = 5.99, 95% CI: 2.09–17.168, p = 0.001) were the influencing factors of the FWR patients with AMI, independently. Additionally, the NPAR and MLR were the predictors of FWR patients, with AUC of 0.811 and 0.778, respectively (both p < 0.001).

Conclusions

In summary, the emergency PCI and ACEI/ARB treatment were independent protective factors for FWR patients with AMI, while the increase of MLR and NPAR were independent risk factors. What's more, NPAR and MLR are good indicators for predicting FWR.

Dietary Menthol Attenuates Inflammation and Cardiac Remodeling After Myocardial Infarction via the Transient Receptor Potential Melastatin 8

BACKGROUND

Transient receptor potential melastatin subtype 8 (TRPM8) is a cold-sensing cation channel, mainly localized in the sensory neurons, which can be activated by menthol, a compound with a naturally cold sensation in mint. However, the effect of TRPM8 activation in inflammation and cardiac remodeling after myocardial infarction (MI) is not well defined.

METHODS

TRPM8 knockout (KO) mice (TRPM8-/-) and their wild-type littermates, aged 8 weeks, were randomly divided into sham and MI groups and were fed with chow or chow plus menthol.

RESULTS

Dietary menthol significantly attenuated MI injury, evidenced by decreased survival rates and plasma cardiac troponion I levels, reduced infarct size and cardiomyocytes, declined collagen deposition, and rescued cardiac function and hemodynamics. However, these effects of menthol disappeared when mice were lacking TRPM8. Furthermore, feeding of menthol ameliorated elevated expression of inflammatory cytokines and chemokines, and aggravated inflammation infiltration in the MI mice but not in TRPM8-/- mice. In addition, menthol treatment increased the release of calcitonin gene-related peptide (CGRP), which were absent in TRPM8-/- mice.

CONCLUSIONS

In conclusion, our results suggest that dietary menthol can protect against inflammation and cardiac remodeling after MI through activation of TRPM8.

Natural cardiac death after stent implantation with iatrogenic injury of a coronary artery

In forensic practice, autopsies are regularly carried out in cases of suspected medical malpractice to determine whether a treatment resulted in death. Intraoperative deaths, as well as deaths shortly after an operation, can be particularly suspicious as iatrogenic. We report a case of a 75-year-old woman with a complaint of intermittent angina pectoris who underwent cardiac catheterization. Intra-interventionally, coronary artery dissection occurred and was stabilized by the placement of two stents. After this procedure, the patient suffered from chest pain. At 5.5 h after the procedure ended, the woman suddenly and unexpectedly died. At forensic autopsy, a hemopericardium with cardiac tamponade was found to have been caused by the rupture of a myocardial infarction that was several days old and had remained clinically unrecognized. This case report illustrates the importance of forensic autopsies in terms of external quality assurance in medicine.

Cardiac Rupture Due to Reinfarction in the Early Phase of Apical Myocardial Infarction

A 72-year-old woman with hypertension, dyslipidemia, and diabetes mellitus presented to our hospital because of the sudden onset of chest pain. Emergency coronary angiography showed acute occlusion of the distal left anterior descending artery and coronary intervention with a drug-eluting stent was performed. Sudden cardiopulmonary arrest occurred on the sixth day of hospitalization, but coronary angiography showed no remarkable progression of the coronary artery diseases, including the site of stent implantation. An autopsy revealed that the cause of the sudden death was apical free wall rupture. In addition, the different timing of acute and sub-acute infarct findings were observed in the apical wall by histology, which indicated cardiac rupture was due to reinfarction at early phase of apical acute myocardial infarction. Although the rate of mechanical complications, including cardiac rupture, is decreasing in the era of primary coronary intervention, in addition to the well-known risk factors of cardiac rupture, the reinfarction of the culprit myocardial site in the early phase of acute myocardial infarction was considered as a possible risk factor of cardiac rupture.

In-hospital worsening renal function is an independent predictor of one-year mortality in patients with acute myocardial infarction

BACKGROUND

We investigated the incidence, clinical predictors and prognostic value of worsening renal function (WRF) regarding 1-year mortality in patients with acute myocardial infarction (AMI).

METHODS

We collected in-hospital data from 447 patients hospitalized for AMI in our institute within 12h of symptoms' onset. WRF was defined as a 25% or more decrease in estimated glomerural filtration rate during hospital stay. From blood samples obtained on admission and throughout hospitalization hemoglobin, white blood cell count, C-reactive protein, B-type natriuretic peptide, plasma glucose, troponin I and baseline and peak creatinine levels were measured. Ejection fraction was calculated on admission with 2D echocardiography. All patients underwent coronary arteriography and the revascularization status (complete or not) was also recorded. The end point was all-cause mortality after one-year of follow-up.

RESULTS

WRF was detected in 63 pts (16.7%) and age, ejection fraction and white blood cell count emerged as the only independent predictors. The incidence of 1-year mortality was 10.7% (48 deaths). Patients with WRF exhibited higher 1-year mortality (37.5% vs. 6.3%, log rank p<0.001) and were characterized by more severe and less completely treated coronary artery disease, greater degree of myocardial necrosis and marked neurohormonal activation. By applying multivariate Cox regression analysis WRF, B-type natriuretic peptide, ejection fraction and admission diastolic blood pressure were identified as the only independent predictors of death.

CONCLUSIONS

WRF is associated with adverse 1-year outcome in patients with AMI. Close monitoring of renal function in the acute phase of MI may substantially contribute to long-term risk stratification.

Fatal myocardial rupture after acute myocardial infarction complicated by heart failure, left ventricular dysfunction, or both: the VALsartan In Acute myocardial iNfarcTion Trial (VALIANT)

BACKGROUND

Myocardial rupture is a relatively rare and usually fatal complication of myocardial infarction (MI). Early recognition of patients at greatest risk of myocardial rupture provides an opportunity for early intervention.

METHODS

VALIANT was a double-blind, randomized, controlled trial comparing valsartan, captopril, and their combination in high-risk patients post-MI. Myocardial rupture was identified by autopsy (available in 138/589 patients dying within 30 days of index MI), echocardiography, direct surgical visualization, or presence of hemopericardium. An independent clinical end points committee reviewed medical records for all deaths or suspected nonfatal cardiovascular events.

RESULTS

Rupture was identified in 45 (0.31%) patients enrolled in VALIANT, occurring 9.8 +/- 6.0 days after the qualifying MI. Rupture accounted for 7.6% (45/589) of all deaths occurring in the first 30 days of follow-up and 24% (33/138) of deaths in which autopsies were obtained. Compared with survivors, rupture was associated with increased age, hypertension, increased Killip class, lower estimated glomerular filtration rate, and Q wave MI, and inversely related to beta-blocker and diuretic use. Compared with patients who died of other causes within 30 days, patients with myocardial rupture were more likely to have had an inferior MI, Q wave MI, or hypertension; to have used oral anticoagulants; or to have received thrombolytic therapy.

CONCLUSIONS

Although rare, myocardial rupture accounted for nearly one fourth of all deaths within the first 30 days after high-risk MI, suggesting an estimated incidence of approximately 1% within the first 30 days. A number of clinical characteristics may identify post-MI patients at higher risk of myocardial rupture.

The impact of transient and persistent acute kidney injury on long-term outcomes after acute myocardial infarction

Acute kidney injury is a common complication of acute myocardial infarction and is generally associated with adverse outcomes. We studied the incidence and clinical significance of transient versus persistent acute kidney injury in 1957 patients who survived an ST-elevation acute myocardial infarction. We divided the patients into 5 groups based on changes in serum creatinine level during hospitalization. Mild acute kidney injury (creatinine 0.3-0.49 mg/dl above baseline) occurred in 156 patients and was transient (resolved during their hospital stay) in 61. Moderate/severe acute kidney injury (creatinine more than or 0.5 mg/dl above baseline) was found in 138 patients and was transient in 60. Compared to patients without acute kidney injury, the adjusted hazard ratio for mortality was 1.2 in patients with mild, transient acute kidney injury and 1.8 in patients with mild, persistent injury where the creatinine remained elevated. Patients with persistent moderate/severe acute kidney injury had the highest mortality (hazard ratio 2.4), whereas patients with transient moderate/severe injury had an intermediate risk (hazard ratio of 1.7). A similar relationship was present between acute kidney injury and admissions for heart failure. Our study shows that dynamic changes in renal function during acute myocardial infarction are strongly related to long-term mortality and heart failure.

Transient receptor potential vanilloid gene deletion exacerbates inflammation and atypical cardiac remodeling after myocardial infarction

The transient receptor potential vanilloid (TRPV1) channels expressed in sensory afferent fibers innervating the heart may be activated by protons or endovanilloids released during myocardial ischemia (MI), leading to angina. Although our previous in vitro data indicate that TRPV1 activation may preserve cardiac function after ischemia-reperfusion injury, the underlying mechanisms are largely unknown. To test the hypothesis that TRPV1 modulates inflammatory and early remodeling processes to prevent cardiac functional deterioration after myocardial infarction, TRPV1-null mutant (TRPV1(-/-)) and wild-type (WT) mice were subjected to left anterior descending coronary ligation or sham operation. The infarct size was greater in TRPV1(-/-) than in WT mice (P<0.001) 3 days after MI, and the mortality rate was higher in TRPV1(-/-) than in WT mice (P<0.05) 7 days after MI. The levels of plasma cardiac troponin I; cytokines, including tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6; chemokines, including monocyte chemoattractant protein-1 and macrophage inflammatory protein-2; and infiltration of inflammatory cells, including neutrophils, macrophages, and myofibroblasts; as well as collagen contents, were greater in TRPV1(-/-) than in WT mice (P<0.05) in the infarct area on days 3 and 7 after MI. Changes in left ventricular geometry led to increased end-systolic and -diastolic diameters and reduced contractile function in TRPV1(-/-) compared with WT mice. These data show that TRPV1 gene deletion results in excessive inflammation, disproportional left ventricular remodeling, and deteriorated cardiac function after MI, indicating that TRPV1 may prevent infarct expansion and cardiac injury by inhibiting inflammation and abnormal tissue remodeling.

Serum blood urea nitrogen and long-term mortality in acute ST-elevation myocardial infarction

INTRODUCTION

Renal dysfunction is associated with increased mortality in acute coronary syndromes and other cardiovascular diseases. The prognostic value of kidney dysfunction has been investigated using creatinine-based measures of renal function. Few data are available on the prognostic significance of blood urea nitrogen (BUN), a sensitive marker of hemodynamic alterations and renal perfusion.

METHODS

The relationship between estimated glomerular filtration rate (eGFR), BUN on admission and changes in BUN during hospital course and long-term mortality was evaluated in 1507 patients with acute ST-elevation myocardial infarction (STEMI).

RESULTS

During a median follow-up of 27 months (range, 12 to 44 months), 281 patients (18.6%) died. In multivariable Cox regression models, elevated BUN (>or=25 mg/dL) at admission was an independent predictor of mortality after adjustments for clinical variables and eGFR (adjusted hazard ratio [HR] 1.7; 95% confidence interval [CI] 1.2-2.3, P=0.0015). Similar results were obtained for elevated BUN/creatinine ratio (>or=25) at admission (adjusted HR 2.0; 95% CI 1.4-2.8; P<0.0001). An increase in BUN 50% above admission value occurred in 260 of patients (17.3%) during hospital course, and was associated with increased risk of mortality after adjustments of clinical variables, eGFR and BUN on admission (HR, 1.7 95% CI 1.3-2.2; P<0.0001).

DISCUSSION

Elevated BUN and BUN/creatinine ratio on admission are independent predictors of long-term mortality in patients with STEMI. An increase in BUN level during hospital course portends adverse outcome independent of eGFR and BUN on admission.

Free-wall rupture of the myocardium following infarction: a changing clinical portrait in the reperfusion era: a case report

Free wall rupture of the myocardium is an important complication and major cause of death following acute transmural (ST segment elevation) myocardial infarction. Pathologic changes on a cellular level may combine with mechanical stressors to weaken the myocardium postinfarction. Risk factors for myocardial rupture include advanced age, female gender, prior hyper-tension, first myocardial infarction, late presentation, lack of collateral blood flow, and persisting chest pain and ST segment elevations. Thrombolytic therapy does not increase risk of rupture when given early in myocardial infarction, but late thrombolytic therapy may heighten risk. Primary percutaneous coronary intervention for acute myocardial infarction has reduced the incidence of myocardial rupture compared to thrombolytic therapy. This advantage likely can be ascribed to higher rates of immediate reperfusion with catheter techniques, as well as to the avoidance of thrombolytic-mediated hemorrhagic transformation of the infarction zone. Careful regulation of blood pressure and pulse using nitrates and beta-adrenergic blockers may mitigate the tendency toward myocardial rupture. Early and accurate diagnosis based on clinical and echocardiographic evidence can lead to successful surgical treatment.

Angiotensin type 2 receptor is expressed in murine atherosclerotic lesions and modulates lesion evolution

BACKGROUND

In the vasculature, the angiotensin type 2 (AT2) receptor (AT2R) exerts antiproliferative, antifibrotic, and proapoptotic effects. Normal adult animals have low AT2R expression; however, vascular injury and exposure to proinflammatory cytokines augment AT2R levels. We hypothesized that AT2R expression increases during initiation and progression of atherosclerosis.

METHODS AND RESULTS

Atherosclerotic lesions of apolipoprotein (Apo) E(-/-) mice contained AT2Rs, measured by real-time polymerase chain reaction and confirmed by immunohistochemistry. To test the consequences of this expression, male ApoE(-/-), angiotensin II type 2 receptor-deficient (Agtr2-), and ApoE(-/-), wild-type (Agtr2+) mice consumed a high-cholesterol diet from 4 weeks of age. Ten weeks later, overall area and cellular composition of aortic arch lesions did not differ significantly among genotypes. After 16 weeks, ApoE(-/-)/Agtr2+, but not ApoE(-/-)/Agtr2- mice had dramatic decreases in percent positive area of macrophages, smooth muscles, lipids, and collagen. Diminished bromodeoxyuridine incorporation and increased TUNEL staining accompanied these decreases.

CONCLUSIONS

Thus, loss of AT2R during the evolution of atherosclerotic lesions augmented the extent of cellularity of atherosclerotic lesions, establishing AT2R as a modulator of atherogenesis.

Inhospital and 1-year mortality of patients who develop worsening renal function following acute ST-elevation myocardial infarction

BACKGROUND

Recent studies have emphasized the prognostic value of baseline creatinine or estimated creatinine clearance in the setting of acute coronary syndromes. However, the prevalence and prognostic significance of worsening renal function (WRF) in patients with acute ST-elevation myocardial infarction are unknown.

METHODS

We studied 1038 patients presenting with acute ST-elevation infarction. WRF was defined as an increase of > or =0.5 mg/dL in creatinine level at any point during hospital stay. The relation between WRF and subsequent inhospital and 1-year mortality was analyzed by use of multivariate logistic regression and Cox proportional hazards models, respectively, controlling for covariates.

RESULTS

WRF occurred in 98 (9.6%) patients during hospital stay. Baseline renal dysfunction (calculated glomerular filtration rate <60 mL/min) and WRF were strong independent predictors of inhospital mortality (adjusted odds ratios 2.8, 95% CI 1.3-5.9; and 11.4, 95% CI 6.6-19.5, respectively). In a Cox multivariate analysis, both baseline renal dysfunction (adjusted hazard ratio 2.8, 95% CI 1.6-4.9) and WRF (adjusted hazard ratio 7.2, 95% CI 4.9-10.4) remained independent predictors of 1-year mortality. WRF provided incremental prognostic value toward the prediction of 1-year mortality when added to clinical risk predictors and baseline renal function. The increased mortality associated with impaired baseline renal function was largely caused by events occurring in patients with WRF.

CONCLUSION

WRF occurring during admission for ST-elevation myocardial infarction is a powerful and independent predictor of inhospital and 1-year mortality. Small elevations of serum creatinine may serve as a simple marker to identify patients at a very high risk.

[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.

Cardiac rupture complicating myocardial infarction

Rupture of the ventricular free wall is a leading cause of death in patients with acute myocardial infarction (MI). There are a number of risk indicators that are associated with cardiac rupture, such as female gender, old age, hypertension, and first MI. Typical symptoms of cardiac rupture are recurrent or persistent chest pain, syncope, and distension of jugular veins. Electrocardiographic signs may include sinus tachycardia, new Q-waves in 2 or more leads, persistent or recurrent ST segment elevation, deviation of expected evolutionary T-wave pattern, and electromechanical dissociation in end-stage cases. Once patients at risk have been identified using clinical symptoms and electrocardiographic signs, a fast and sensitive diagnostic test to confirm cardiac rupture is transthoracic echocardiography (TTE). New insights in the etiology of subacute myocardial rupture suggests that defective cardiac remodeling may predispose the heart for rupture. The matrix metalloproteinase (MMP) system has been shown to play an important role in cardiac extracellular matrix (ECM) remodeling and cardiac rupture. Current therapy of cardiac rupture consists mainly of surgery, and conservative management with hemodynamic monitoring, prolonged bed rest, beta-blockers, and angiotensin-converting enzyme (ACE) inhibitors in selected cases.