Systemic and local vascular inflammation and arterial reactive oxygen species generation in patients with advanced cardiovascular diseases.

Background: Systemic inflammation may cause endothelial activation, mediate local inflammation, and accelerate progression of atherosclerosis. We examined whether the levels of circulating inflammatory cytokines reflect local vascular inflammation and oxidative stress in two types of human arteries. Methods: Human internal mammary artery (IMA) was obtained in 69 patients undergoing coronary artery bypass graft (CABG) surgery and left anterior descending (LAD) artery was obtained in 17 patients undergoing heart transplantation (HTx). Plasma levels of tumor necrosis factor α (TNF-α), interleukin-6 (IL-6) and interleukin-1ß (IL-1ß) were measured using ELISA, high-sensitivity C-reactive protein (hs-CRP) was measured using Luminex, and mRNA expression of proinflammatory cytokines in the vascular tissues was assessed. Furthermore, formation of superoxide anion was measured in segments of IMA using 5 uM lucigenin-dependent chemiluminescence. Vascular reactivity was measured using tissue organ bath system. Results: TNF-α, IL-6 and IL-1ß mRNAs were expressed in all studied IMA and LAD segments. Plasma levels of inflammatory cytokines did not correlate with vascular cytokine mRNA expression neither in IMA nor in LAD. Plasma TNF-α and IL-6 correlated with hs-CRP level in CABG group. Hs-CRP also correlated with TNF-α in HTx group. Neither vascular TNF-α, IL-6 and IL-1ß mRNA expression, nor systemic levels of either TNF-α, IL-6 and IL-1ß were correlated with superoxide generation in IMAs. Interestingly, circulating IL-1ß negatively correlated with maximal relaxation of the internal mammary artery (r = -0.37, p = 0.004). At the same time the mRNA expression of studied inflammatory cytokines were positively associated with each other in both IMA and LAD. The positive correlations were observed between circulating levels of IL-6 and TNF-α in CABG cohort and IL-6 and IL-1ß in HTx cohort. Conclusions: This study shows that peripheral inflammatory cytokine measurements may not reflect local vascular inflammation or oxidative stress in patients with advanced cardiovascular disease (CVD). Circulating pro-inflammatory cytokines generally correlated positively with each other, similarly their mRNA correlated in the arterial wall, however, these levels were not correlated between the studied compartments.

ECG patterns suggestive of high-risk coronary anatomy in non-ST-segment elevation acute coronary syndrome - an analysis of real-world patients.

Introduction: Electrocardiographic (ECG) patterns suggestive of high-risk coronary anatomy are indications for an urgent invasive approach in non-ST-segment elevation acute coronary syndrome (NSTE-ACS). Aim: To estimate the frequency of the observed phenomenon and assess the clinical characteristics of NSTE-ACS subjects associated with Wellens syndrome, the de Winter sign, or ST-segment depressions by ≥ 1 mm in ≥ 6 classic ECG leads with simultaneous ST-segment elevation in aVR and/or V1. Material and methods: Out of 207 pre-screened subjects diagnosed with NSTE-ACS, 64 patients (26 women and 38 men) with complete medical records (including admission ECG and coronary angiography during the index hospitalization), and significant culprit stenosis or occlusion of the left main coronary artery (LMCA) or the proximal/middle segment of the left anterior descending artery (LAD) entered the final analysis. Clinical characteristics of patients exhibiting any of the high-risk ECG patterns was compared to their counterparts with significant lesions in LMCA or proximal/middle LAD without any of the high-risk ECG patterns. Results: Among 64 patients with significant culprit lesions in LMCA or LAD, 19 (29.69%) exhibited one of the high-risk ECG patterns: Wellens syndrome (n = 10), the de Winter sign (n = 0), or multiple ST-segment depressions (n = 9). Clinical characteristics were comparable in 19 NSTE-ACS patients with the high-risk ECG patterns and their 45 counterparts. Conclusions: Because ECG patterns suggestive of high-risk coronary anatomy are relatively frequent in patients with NSTE-ACS and culprit lesions in LMCA or LAD, their early recognition is of clinical importance.

The change of angina levels in patients with chronic coronary syndromes and coronary microcirculatory dysfunction - a prospective study with 24 months follow-up.

Introduction: A substantial proportion of patients with chronic coronary syndromes suffer from angina even after medical treatment and revascularization. Coronary microvascular dysfunction (CMD) is discussed as a potential mechanism. Aim: To assess angina status in patients with chronic coronary syndromes undergoing functional assessment of coronary circulation regarding the presence of coronary microcirculatory dysfunction. Material and methods: The study included 101 consecutive patients referred for coronary angiography requiring functional stenosis assessment, with median age of 66 years, 74% male, diagnosed or treated for dyslipidemia (91%) and diabetes type 2 (42%), 20% with a history of prior non-ST myocardial infarction. Fractional flow reserve (FFR), coronary flow reserve (CFR), resistive reserve ratio (RRR), and index of microcirculatory resistance (IMR) were measured. The diagnosis of CMD was defined by either IMR ≥ 25 units or CFR ≤ 2.0 in case of no significant stenosis. A change of one CCS class over 24 months follow-up was considered clinically significant. Results: In patients without CMD diagnosis, there was a significant decrease in angina intensity (p < 0.001). Lack of angina improvement was associated with lower median RRR (2.30 (1.70, 3.30) vs. 3.05 (2.08, 4.10), p = 0.004) and lower median CFR (1.90 (1.40, 2.50) vs. 2.30 (IQR: 1.60, 3.00), p = 0.021), as compared to patients with angina improvement. Conclusions: The presence of CMD is a risk factor for no angina improvement. Impaired coronary resistive reserve ratio and lower microvascular reactivity may be one of the pathomechanisms leading to the lack of angina improvement in patients with chronic coronary syndromes.

Impaired coronary flow reserve in patients with poor type 2 diabetes control: Preliminary results from prospective microvascular dysfunction registry.

BACKGROUND: Type 2 diabetes (DM) is a common comorbidity associated with cardiovascular disease, especially when poor glucose control is present. Extracardiac microcirculatory complications prevalence is well documented, however coronary microcirculatory dysfunction (CMD) seem to be underreported in this group. METHODS: The present study analyzed coronary physiology measurements (coronary flow reserve [CFR], index of microcirculatory resistance [IMR], resistance reserve ratio [RRR]) in 47 diabetic patients (21 subjects with poor glycemia control defined as fasting glucose levels > 7.2 mmol/L and 26 with normal fasting glucose), and compared to 54 non-diabetic controls, who had undergone coronary angiography due to symptoms of chronic coronary syndrome. The median age of patients was 65.5 [59.0; 73.0] years old, 74% male, similar in terms of cardiovascular risk factors and prior myocardial infarction. Insulin was used by 19% of diabetic patients with poor glucose control and by 15% of those with DM and low fasting glucose. RESULTS: Prevalence of CMD was 38% in poor glycemia control patients, 27% in DM-patients with proper glucose control and 31% of non-diabetics. Median CFR values were the lowest in poor DM control patients compared to both, normal fasting glucose (1.75 [1.37; 2.32] vs. 2.30 [1.75; 2.85], p = 0.026) and to non-diabetics (1.75 [1.37; 2.32] vs. 2.15 [1.50; 2.95], p = 0.045). Levels of IMR, RRR and MRR did not differ significantly between compared groups (p > 0.05 for all comparisons). CONCLUSIONS: Poor glycemia control in type 2 DM might be associated with a higher prevalence of CMD driven by decreased coronary flow reserve, however, further research in larger groups of patients should be performed to confirm this observation.

The impact of coronary microvascular dysfunction on the discordance between fractional flow reserve and resting full-cycle ratio in patients with chronic coronary syndromes.

Background: Resting full-cycle ratio (RFR) is an alternative to fractional flow reserve (FFR) for the evaluation of borderline coronary artery lesions. Although FFR and RFR results are discordant in some cases, factors associated with the discordance remain unclear. The role of coronary microvascular dysfunction (CMD) is discussed as a potential mechanism to explain these discrepancies. Aim: The study aimed to assess concordance between RFR and FFR in a real-life cohort from a high-volume center regarding the role of CMD. Methods: Consecutive patients with borderline coronary lesions undergoing coronary functional testing for chronic coronary syndromes were included in the study. Measurements of RFR and FFR were performed alongside additional coronary flow reserve (CFR), resistance reserve ratio (RRR), and an index of microcirculatory resistance (IMR) measurements. CMD was defined according to the current guideline by either IMR ≥25 or CFR ≤2.0 in vessels with no significant stenosis. Results: Measurements were performed in 157 coronary arteries, in 101 patients, with a median age of 66 y., 74% male, with prior history of arterial hypertension (96%), dyslipidaemia (91%), and diabetes (40%). The median value of vessel diameter stenosis was 45% according to QCA.Overall, FFR and RFR values were significantly correlated (r = 0.66, p < 0.001), where positive FFR/negative RFR and negative FFR/positive RFR were observed in 6 (3.8%) and 38 (24.2%) of 157 vessels. The RFR/FFR discrepancy was present in 44 (28%) of measurements. CMD was confirmed in 28 (64%) of vessels with discrepant RFR/FFR and in 46 (41%) of vessels with concordant results (p = 0.01). In discordant RFR/FFR vessels, as compared to concordant ones, significantly lower values of CFR [median 1.95 (IQR: 1.37, 2.30) vs. 2.10 (IQR: 1.50, 3.00), p = 0.030] and RRR [median 2.50 (IQR: 1.60, 3.10) vs. 2.90 IQR (1.90, 3.90), p = 0.048] were observed.Main predictors of RFR/FFR discrepancy in a univariate regression analysis were: higher age of patients [OR = 1.06 (1.01; 1.10), p = 0.010], presence of CMD [OR = 2.51 (1.23; 5.25), p = 0.012], lower CFR [OR = 1.64 (1.12; 2.56), p = 0.018], and lower RRR values [OR = 1.35 (95% CI: 1.03; 1.83), p = 0.038]. Conclusion: In discrepant RFR/FFR vessels, CMD is more prevalent than in concordant RFR/FFR measurements, which can be driven by lower CFR or RRR values. Further research is needed to confirm this observation.

Clinical Characteristics Predicting Worse Long-Term Outcomes in Patients with Myocardial Infarction and Non-Obstructive Coronary Arteries (MINOCA).

Non-obstructive coronary artery disease occurs in 3.5-15% of patients presenting with acute myocardial infarction. This group of patients has a poor prognosis. Identification of factors that predict worse outcomes in myocardial infarction with non-obstructive coronary arteries (MINOCA) is therefore important. Patients with a diagnosis of MINOCA (n = 110) were enrolled in this single-center, retrospective registry. Follow-up was performed 12, 24 and 36 months after discharge. The primary composite endpoint was defined as myocardial infarction, coronary revascularization, stroke or TIA, all-cause death, or hospital readmission due to any cardiovascular event. The mean age of the study group was 64.9 (± 13.5) years and 38.2% of patients were male. The occurrence of the primary composite endpoint was 36.4%. In a COX proportional hazards model analysis, older age (p = 0.027), type 2 diabetes (p = 0.013), history of neoplasm (p = 0.004), ST-segment depression (p = 0.018) and left bundle branch block/right bundle branch block (p = 0.004) by ECG on discharge, higher Gensini score (p = 0.022), higher intraventricular septum (p = 0.007) and posterior wall thickness increases (p = 0.001) were shown to be risk factors for primary composite endpoint occurrence. Our study revealed that several factors such as older age, type 2 diabetes, ST-segment depression and LBBB/RBBB in ECG on discharge, higher Gensini score, and myocardial hypertrophy and history of neoplasm may contribute to worse clinical outcomes in MINOCA patients.

Serum and Vascular Stiffness Biomarkers Associated with the Severity of Degenerative Aortic Valve Stenosis and Cardiovascular Outcomes.

Background: Although degenerative aortic valve stenosis (DAS) is the most prevalent growth-up congestive heart valve disease, still little known about relationships between DAS severity, vascular stiffness (VS), echocardiographic parameters, and serum biomarkers in patients undergoing transcatheter (TAVR) or surgical aortic valve replacement (SAVR). The objective of this study was to identify biomarkers associated with DAS severity, and those that are associated with cardiovascular death (CVD) and episodes of chronic heart failure (CHF) exacerbation. Methods: A total of 137 patients with initially moderate-to-severe DAS were prospectively evaluated for the relationship between DAS severity, baseline VS, and serum biomarkers (uPAR, GDF-15, Gal-3, IL-6Rα, ET-1, PCSK9, RANTES/CCL5, NT-proBNP, and hs-TnT), and were followed-up for 48 months. The prognostic significance of each variable for CVD and CHF risk was measured by hazard ratio of risk (HR), which was calculated by Cox's proportional hazard model. Results: DAS severity showed correlations with IL-6Rα (r = 0.306, p < 0.001), uPAR (r = 0.184, p = 0.032), and NT-proBNP (r = −0.389, p < 0.001). Levels of ET-1 and Gal-3 were strongly correlated with VS parameters (r = 0.674, p < 0.001; r = 0.724, p < 0.001). Out of 137 patients, 20 were referred to TAVR, 88 to SAVR, and 29 to OMT. In TAVR patients, the highest levels of ET-1, Gal-3, and VS were found as compared to other patients. The highest incidence of CVD was observed in patients who underwent TAVR (35%), compared to SAVR (8%) and OMT (10.3%) (p = 0.004). In a multivariate analysis, ET-1 occurred predictive of CVD risk (HR 25.1, p = 0.047), while Gal-3 > 11.5 ng/mL increased the risk of CHF exacerbation episodes requiring hospital admission by 12%. Conclusions: Our study indicated that ET-1 and Gal-3 levels may be associated with the outcomes in patients with DAS.

Association of Increased Vascular Stiffness with Cardiovascular Death and Heart Failure Episodes Following Intervention on Symptomatic Degenerative Aortic Stenosis.

BACKGROUND: The resistive (RI) and pulsatile (PI) indices are markers of vascular stiffness (VS) which are associated with outcomes in patients with cardiovascular disease. We aimed to assess whether VS might predict incidence of cardiovascular death (CVD) and heart failure (HF) episodes following intervention on degenerative aortic valve stenosis (DAS). METHODS: The distribution of increased VS (RI ≥ 0.7 and PI ≥ 1.3) from supra-aortic arteries was assessed in patients with symptomatic DAS who underwent aortic valve replacement (AVR, n = 127) or transcatheter aortic valve implantation (TAVI, n = 119). During a 3-year follow-up period (FU), incidences of composite endpoint (CVD and HF) were recorded. RESULTS: Increased VS was found in 100% of TAVI patients with adverse event vs. 88.9% event-free TAVI patients (p = 0.116), and in 93.3% of AVR patients with event vs. 70.5% event-free (p = 0.061). Kaplan-Mayer free-survival curves at 1-year and 3-year FU were 90.5% vs. 97.1 % and 78% vs. 97.1% for patients with increased vs. lower VS. (p = 0.014). In univariate Cox analysis, elevated VS (HR 7.97, p = 0.04) and age (HR 1.05, p = 0.024) were associated with risk of adverse outcomes; however, both failed in Cox multivariable analysis. CONCLUSIONS: Vascular stiffness is associated with outcome after DAS intervention. However, it cannot be used as an independent outcome predictor.

Importance of Increased Arterial Resistance in Risk Prediction in Patients with Cardiovascular Risk Factors and Degenerative Aortic Stenosis.

BACKGROUND: Cardiovascular disease is a leading cause of heart failure (HF) and major adverse cardiac and cerebral events (MACCE). OBJECTIVE: To evaluate impact of vascular resistance on HF and MACCE incidence in subjects with cardiovascular risk factors (CRF) and degenerative aortic valve stenosis (DAS). METHODS: From January 2016 to December 2018, in 404 patients with cardiovascular disease, including 267 patients with moderate-to-severe DAS and 137 patients with CRF, mean values of resistive index (RI) and pulsatile index (PI) were obtained from carotid and vertebral arteries. Patients were followed-up for 2.5 years, for primary outcome of HF and MACCE episodes. RESULTS: RI and PI values in patients with DAS compared to CRF were significantly higher, with optimal cut-offs discriminating arterial resistance of ≥0.7 for RI (sensitivity: 80.5%, specificity: 78.8%) and ≥1.3 for PI (sensitivity: 81.3%, specificity: 79.6%). Age, female gender, diabetes, and DAS were all independently associated with increased resistance. During the follow-up period, 68 (16.8%) episodes of HF-MACCE occurred. High RI (odds ratio 1.25, 95% CI 1.13-1.37) and PI (odds ratio 1.21, 95% CI 1.10-1.34) were associated with risk of HF-MACCE. CONCLUSIONS: An accurate assessment of vascular resistance may be used for HF-MACCE risk stratification in patients with DAS.

Coronary revascularization after heart transplant - the search for prognostic factors.

INTRODUCTION: Survival after heart transplantation (HTX) is extended due to continuous improvement of medical care, allowing enough time for coronary artery vasculopathy to develop. Data on the clinical outcome of cardiac transplantation patients after percutaneous coronary intervention (PCI) are still not extensively explored. The aim of our study was to assess whether heart transplantation itself compromises the outcome in patients undergoing percutaneous coronary intervention and to assess survival rates as well as major cardiovascular complications in heart transplant recipients who had undergone PCI. MATERIAL AND METHODS: Thirty-three heart transplant recipients who had undergone PCI in the years 2005 to 2015 in a single center were matched by age, sex and main risk factors of arteriosclerosis with 33 controls without heart transplant history. Mean age of patients was 54.6 ±11.4 years in the HTX group and 58.8 ±10.8 years in controls. Median time from heart transplant to PCI was 13 years (4.4-22 years). Case and control groups did not differ in terms of standard risk factors of coronary artery disease, apart from chronic kidney disease, which was present in 70% of patients after heart transplantation, and dyslipidemia, which was present in 91% of control subjects. RESULTS: Patients after HTX had worse survival compared to controls (p = 0.04). When adjusted for comorbidities in the Cox regression model, there was no significant difference in survival between cardiac transplant recipients and the control group (HR = 1.06; 95% CI: 0.10-11.24). Chronic renal disease was a significant predictor of all-cause mortality (HR = 29.9; 95% CI: 2.3-393). Considering other endpoints, HTX patients had considerably higher incidence of severe bleeding compared to the control group (27% vs. 3%, p < 0.05). CONCLUSIONS: There was no significant difference in myocardial infarction rate, revascularization or hospitalization rates.

NEUTROPHIL-LYMPHOCYTE RATIO AND PLATELET-LYMPHOCYTE RATIO AS PREDICTORS OF CORONARY MICROCIRCULATORY DISEASE OCCURRENCE AND OUTCOME IN PATIENTS WITH CHRONIC CORONARY SYNDROME AND NO SIGNIFICANT CORONARY ARTERY STENOSIS.

OBJECTIVE: Introduction: Index of microcirculatory resistance assessment is an invasive method of measuring coronary microcirculation function. Association between impaired microcirculatory function and higher rate of cardiovascular events was proven. Neutrophil-lymphocyte ratio and platelet-lymphocyte ratio seem to be a promising parameters to predict coronary microcirculatory disease in patients with chronic coronary syndrome. The aim: To determine neutrophil-lymphocyte ratio and platelet-lymphocyte ratio levels in patients with coronary microcirculatory disease and potential association with clinical outcome. PATIENTS AND METHODS: Material and methods: 82 consecutive patients with mean age of 67 years, 67% male, were tested for presence of coronary microcirculatory disease using index of microcirculatory resistance. Neutrophil-lymphocyte ratio and platelet-lymphocyte ratio were calculated based on admission full blood count. Follow-up with major adverse cardiac and cardiovascular events registration was performed (median 24 months). RESULTS: Results: The study showed significantly higher neutrophil-lymphocyte ratio and platelet-lymphocyte ratio in patients with coronary microcirculatory disease compared to control group (3.58±2.61 vs 2.54±1.09 and 164±87.9 vs 124±36.6 respectively). Higher level of platelet-lymphocyte ratio in patients with coronary microcirculatory disease results in worse MACCE-free survival. Optimal cut-off values of neutrophil-lymphocyte ratio and platelet-lymphocyte ratio to detect coronary microcirculatory disease were 3.2 and 181.3, respectively. CONCLUSION: Conclusions: Higher neutrophil-lymphocyte ratio and platelet-lymphocyte ratio are associated with increased index of microcirculatory resistance value. Platelet-lymphocyte ratio may be used as a predictor of worse outcome in patients with coronary microcirculatory disease.

Percutaneous management of long and diffused coronary lesions using newer generation drug-eluting stents in routine clinical practice: long-term outcomes and complication predictors.

INTRODUCTION: Long and diffuse coronary lesions (LDCLs) are routinely subjected to percutaneous management, but long­term clinical outcomes and complication predictors with the use of contemporary stents and techniques remain undetermined. OBJECTIVES: The aim of the study was to address long­term effects of percutaneous management of LDCLs, using contemporary devices and optimization techniques. PATIENTS AND METHODS: Long and diffuse coronary lesion was defined as a lesion requiring an implantation of 30 mm or longer total stent(s) length (TSL) into one coronary artery (bailouts excluded). There were 290 LDCL interventions with the use of newer generation drug­eluting stents (DESs; cobalt chromium everolimus- or zotarolimus-eluting stents) performed between January 2013 and January 2016. RESULTS: The mean (SD) TSL was 55.5 (16.8) mm. The use of intravascular ultrasound / optical coherence tomography was 17.1%, rotablation, 6.9%, and noncompliant balloon, 88.9%. The median (range) follow­up duration was 831 (390-1373) days. All­cause mortality and cardiac death rates were 11.7% and 6.9%, respectively. The myocardial infarction (MI) rate was 6.6%, including target­vessel MI in 4.1%. The rate of clinically­driven repeat revascularization was 13.8%, and of definite or probable LDCL stent thrombosis, 7.2%. Overall patient­oriented adverse event rate (any death, MI, or repeat revascularization) was 25.5%, and device­oriented rate (cardiac death, target vessel­MI, or target lesion restenosis), 13.4%. Adverse outcome predictors were chronic kidney disease, acute coronary syndrome as an indication for the procedure, chronic heart failure with reduced left ventricular ejection fraction, multivessel disease, and coexisting peripheral artery disease, but not lesion­related factors, such as bifurcation, calcification, chronic total occlusion, or TSL. CONCLUSIONS: Adverse outcomes following contemporary LDCL management using newer generation DESs in routine clinical practice are associated with clinical patient characteristics rather than lesion characteristics or TSL. We identified high­risk patient cohorts that may benefit from enhanced surveillance.

Clinical experience with 12-month follow-up in patients after implantation of a novel long-tapered sirolimus drug-eluting stent.

INTRODUCTION: Long lesions contribute to a significant number of percutaneous coronary interventions. AIM: To assess the efficacy and safety of a novel long-tapered drug-eluting stent (DES) at a 12-month follow-up (FU) in patients with long coronary atherosclerotic lesions. MATERIAL AND METHODS: A prospective clinical cohort study was conducted in 32 patients who underwent percutaneous coronary intervention using a BioMime Morph tapered stent (Meril Life Sciences, India). The patients were followed for 3, 6, and 12 months. The safety endpoints were death, myocardial infarction (MI), target lesion revascularization (TLR), target vessel revascularization (TVR), and MACE and/or major bleeding. RESULTS: Mean lesion length was 48 mm (range: 35-70 mm) measured via quantitative coronary analysis (QCA). In most cases, the target lesion was located in the LAD (68.75%). A GuideLiner catheter (Vascular Solutions Inc., MN, USA) was used in 12.5% of procedures; buddy-wire technique in 9.4% of cases. Bifurcation lesions were treated in 40.6% of cases. Additional stent implantation was needed in 56% of the procedures (25% of cases due to proximal or distal dissection, or due to insufficient stent length in 31% of cases). On 12-month FU we observed 1 TLR (3.1%), 1 TVR (3.1%), and 1 non-cardiovascular death. CONCLUSIONS: The long sirolimus-eluting stent with tapered structure was characterized by good deliverability in long coronary lesions, although in some cases "buddy wire" or extension microcatheter use was necessary. Follow-up at 3, 6, and 12 months showed no significant major adverse cardiovascular events related to the device.

Effect of short-term fluctuations in outdoor air pollution on the number of hospital admissions due to acute myocardial infarction among inhabitants of Kraków, Poland.

INTRODUCTION Air pollution is reaching alarming proportions worldwide; however, previous studies concerning the association between air pollution and myocardial infarction (MI) provided conflicting results. OBJECTIVES We evaluated a relationship between short­term fluctuations in outdoor particulate matter (PM) and nitrogen dioxide (NO2) levels and the number of hospitalizations due to MI among the inhabitants of Kraków, Poland. PATIENTS AND METHODS Data on hospitalizations, daily pollutant concentrations, infections, and meteorological parameters were collected from December 2012 to September 2015. Data were assessed using a time­series regression analysis with a distributed lag model. RESULTS An increase of 10 µg/m3 in PM2.5 levels was associated with a higher risk of hospital admission due to MI (odds ratio [OR], 1.32; 95% CI, 1.01-1.40; P = 0.0002). For PM10 the effect was observed only with a simultaneous decrease of 1ºC in the mean daily temperature (OR, 1.08; 95% CI, 1.01-1.17; P = 0.03). Significant effects were observed at lags 5 and 6. The effect of NO2 was significant at lags 0 and 1, but only in patients aged 70 years or older (OR, 1.13; 95% CI, 1.01-1.23; P = 0.007) and those with pulmonary disorders (OR, 1.12; 95% CI, 1.01-1.31; P = 0.01). CONCLUSIONS In all age groups, the short­term elevation in PM2.5 levels was associated with an increased number of daily hospital admissions for MI, whereas for PM10 the effect was significant only with a simultaneous decrease in temperature. The effect of NO2 was observed only in older individuals and patients with pulmonary disorders. A negative clinical effect was more delayed in time in the case of exposure to PM than to NO2.