Successful Catheter Ablation for Paroxysmal Supraventricular Tachycardia with Two Alternating Cycle Lengths.

A 62-year-old male was transferred to our hospital complaining of palpitations. His heart rate was 185/min. Electrocardiogram showed a narrow QRS regular tachycardia and the tachycardia changed spontaneously to another narrow QRS tachycardia with two alternating cycle lengths. The arrhythmia was stopped by the administration of adenosine triphosphate. Findings from electrophysiological study suggested that there was an accessory pathway (AP) and dual atrioventricular (AV) nodal pathways. After AP ablation, any other tachyarrythmias were not induced. We supposed that the tachycardia was paroxysmal supraventricular tachycardia involving AP and anterograde conduction alternating between slow and fast AV nodal pathways.

Prehospital Administration of Aspirin and Nitroglycerin for Patients With Suspected Acute Coronary Syndrome　- A Systematic Review.

Background: Recent guidelines for acute coronary syndrome (ACS) recommend prehospital administration of aspirin and nitroglycerin for ACS patients. However, there is no clear evidence to support this. We investigated the benefits and harms of prehospital administration of aspirin and nitroglycerin by non-physician healthcare professionals in patients with suspected ACS. Methods and Results: We searched the PubMed database and used the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach to assess the certainty of evidence. Three retrospective studies for aspirin and 1 for nitroglycerin administered in the prehospital setting to patients with acute myocardial infarction were included. Prehospital aspirin administration was associated with significantly lower 30-day and 1-year mortality compared with aspirin administration after arrival at hospital, with odds ratios (OR) of 0.59 (95% confidence interval [CI] 0.35-0.99) and 0.47 (95% CI 0.36-0.62), respectively. Prehospital nitroglycerin administration was also associated with significantly lower 30-day and 1-year mortality compared with no prehospital administration (OR 0.34 [95% CI 0.24-0.50] and 0.38 [95% CI 0.29-0.50], respectively). The certainty of evidence was very low in both systematic reviews. Conclusions: Our systematic reviews suggest that prehospital administration of aspirin and nitroglycerin by non-physician healthcare professionals is beneficial for patients with suspected ACS, although the certainty of evidence is very low. Further investigation is needed to determine the benefit of the prehospital administration of these agents.

Prehospital Activation of the Catheterization Laboratory Among Patients With Suspected ST-Elevation Myocardial Infarction Outside of a Hospital　- Systematic Review and Meta-Analysis.

Background: In the management of patients with ST-elevation myocardial infarction (STEMI), system delays for reperfusion therapy are still a matter of concern. We investigated the impact of prehospital activation of the catheterization laboratory in the management of STEMI patients. Methods and Results: This is a systematic review of observational studies. A search was conducted of the PubMed database from inception to July 2020 to identify articles for inclusion in the study. The critical outcomes were short- and long-term mortality. The important outcome was door-to-balloon time. The GRADE approach was used to assess the certainty of the evidence. Seven studies assessed short-term mortality; 1,541 were assigned to the prehospital activation (PH) group and 1,191 were assigned to the emergency department activation (ED) group. There were 26 fewer deaths per 1,000 patients in the PH group. Three studies assessed long-term mortality; 713 patients were assigned to the PH group and 1,026 were assigned to the ED group. There were 54 fewer deaths per 1,000 patients among the PH group. Five studies assessed door-to-balloon time; 959 were assigned to the PH group and 631 to the ED group. Door-to-balloon time was 33.1 min shorter in the PH group. Conclusions: Prehospital activation of the catheterization laboratory resulted in lower mortality and shorter door-to-balloon time for patients with suspected STEMI outside of a hospital.

Supplemental Oxygen and Acute Myocardial Infarction　- A Systematic Review and Meta-Analysis.

Background: In Japan, oxygen is commonly administered during the acute phase of myocardial infarction (MI) to patients without oxygen saturation monitoring. In this study we assessed the effects of supplemental oxygen therapy, compared with ambient air, on mortality and cardiac events by synthesizing evidence from randomized controlled trials (RCTs) of patients with suspected or confirmed acute MI. Methods and Results: PubMed was systematically searched for full-text RCTs published in English before June 21, 2020. Two reviewers independently screened the search results and appraised the risk of bias. The estimates for each outcome were pooled using a random-effects model. In all, 2,086 studies retrieved from PubMed were screened. Finally, 7,322 patients from 9 studies derived from 4 RCTs were analyzed. In-hospital mortality in the oxygen and ambient air groups was 1.8% and 1.6%, respectively (risk ratio [RR] 0.90; 95% confidence interval [CI] 0.38-2.10]); 0.8% and 0.5% of patients, respectively, experienced recurrent MI (RR 0.44; 95% CI 0.12-1.54), 1.5% and 1.6% of patients, respectively, experienced cardiac shock (RR 1.10; 95% CI 0.77-1.59]), and 2.4% and 2.0% of patients, respectively, experienced cardiac arrest (RR 0.91; 95% CI 0.43-1.94). Conclusions: Routine supplemental oxygen administration may not be beneficial or harmful, and high-flow oxygen may be unnecessary in normoxic patients in the acute phase of MI.

Performance of the 0-Hour/1-Hour Algorithm for Diagnosing Myocardial Infarction in Patients With Chest Pain in the Emergency Department　- A Systematic Review and Meta-Analysis.

Background: This study assessed the diagnostic performance of the 0-hour/1-hour (0/1-h) algorithm to rule in and rule out acute myocardial infarction (MI) in patients presenting to the emergency department (ED) for suspected acute coronary syndrome without ST-segment elevation, as recommended in the 2015 European Society of Cardiology (ESC) guideline. Methods and Results: Following the Preferred Reporting Items for a Systematic Review and Meta-analysis of Diagnostic Test Accuracy (PRISMA-DTA) guidelines, a systematic review was conducted using the PubMed database from inception to March 31, 2020. We included any article published in English investigating the diagnostic performance of the ESC 0/1-h algorithm for diagnosing MI in patients with chest pain visiting the ED. Of 651 studies identified as potentially available for the study, 7 studies including 16 databases were analyzed. A meta-analysis of the diagnostic accuracy of the 0/1-h algorithm using high-sensitivity cardiac troponin I (hs-cTn) with 6 observational databases showed a pooled sensitivity of 99.3% (95% confidence interval [CI] 98.5-99.7%) and a pooled specificity of 90.1% (95% CI 80.7-95.2%). A meta-analysis of the diagnostic accuracy of 10 observational databases of the ESC 0/1-h algorithm using hs-cTn revealed a pooled sensitivity of 99.3% (95% CI 96.9-99.9%) and a pooled specificity of 91.7% (95% CI 83.5-96.1%). Conclusions: Our results demonstrate that the ESC 0/1-h algorithm can effectively rule in and rule out patients with non-ST-segment elevation MI.

Systematic Review and Meta-Analysis of Diagnostic Accuracy to Identify ST-Segment Elevation Myocardial Infarction on Interpretations of Prehospital Electrocardiograms.

Background: The aim of this study was to assess and discuss the diagnostic accuracy of prehospital ECG interpretation through systematic review and meta-analyses. Methods and Results: Relevant literature published up to July 2020 was identified using PubMed. All human studies of prehospital adult patients suspected of ST-segment elevation myocardial infarction in which prehospital electrocardiogram (ECG) interpretation by paramedics or computers was evaluated and reporting all 4 (true-positive, false-positive, false-negative, and true-negative) values were included. Meta-analyses were conducted separately for the diagnostic accuracy of prehospital ECG interpretation by paramedics (Clinical Question [CQ] 1) and computers (CQ2). After screening, 4 studies for CQ1 and 6 studies for CQ2 were finally included in the meta-analysis. Regarding CQ1, the pooled sensitivity and specificity were 95.5% (95% confidence interval [CI] 82.5-99.0%) and 95.8% (95% CI 82.3-99.1%), respectively. Regarding CQ2, the pooled sensitivity and specificity were 85.4% (95% CI 74.1-92.3%) and 95.4% (95% CI 87.3-98.4%), respectively. Conclusions: This meta-analysis suggests that the diagnostic accuracy of paramedic prehospital ECG interpretations is favorable, with high pooled sensitivity and specificity, with an acceptable estimated number of false positives and false negatives. Computer-assisted ECG interpretation showed high pooled specificity with an acceptable estimated number of false positives, whereas the pooled sensitivity was relatively low.

Impact of Prehospital 12-Lead Electrocardiography and Destination Hospital Notification on Mortality in Patients With Chest Pain　- A Systematic Review.

Background: To achieve early reperfusion therapy for ST-elevation myocardial infarction (STEMI), proper and prompt patient transportation and activation of the catheterization laboratory are required. We investigated the efficacy of prehospital 12-lead electrocardiogram (ECG) acquisition and destination hospital notification in patients with STEMI. Methods and Results: This is a systematic review of observational studies. We searched the PubMed database from inception to March 2020. Two reviewers independently performed literature selection. The critical outcome was short-term mortality. The important outcome was door-to-balloon (D2B) time. We used the GRADE approach to assess the certainty of the evidence. For the critical outcome, 14 studies with 29,365 patients were included in the meta-analysis. Short-term mortality was significantly lower in the group with prehospital 12-lead ECG acquisition and destination hospital notification than in the control group (odds ratio 0.72; 95% confidence interval [CI] 0.61-0.85; P<0.0001). For the important outcome, 10 studies with 2,947 patients were included in the meta-analysis. D2B time was significantly shorter in the group with prehospital 12-lead ECG acquisition and destination hospital notification than in the control group (mean difference -26.24; 95% CI -33.46, -19.02; P<0.0001). Conclusions: Prehospital 12-lead ECG acquisition and destination hospital notification is associated with lower short-term mortality and shorter D2B time than no ECG acquisition or no notification among patients with suspected STEMI outside of a hospital.

Effects of Door-In to Door-Out Time on Mortality Among ST-Segment Elevation Myocardial Infarction Patients Transferred for Primary Percutaneous Coronary Intervention　- Systematic Review and Meta-Analysis.

Background: Primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI) is now widely accepted. Recent guidelines have focused on total ischemic time, because shorter total ischemic time is associated with a more favorable prognosis. The door-in to door-out (DIDO) time, defined as time from arrival at a non-PCI-capable hospital to leaving for a PCI-capable hospital, may affect STEMI patient prognosis. However, a relevant meta-analysis is lacking. Methods and Results: We searched PubMed for clinical studies comparing short-term (30-day and in-hospital) mortality rates of STEMI patients undergoing primary PCI with DIDO times of ≤30 vs. >30 min. Two investigators independently screened the search results and extracted the data. Random effects estimators with weights calculated by the inverse variance method were used to determine pooled risk ratios. The search retrieved 1,260 studies; of these, 2 retrospective cohort studies (15,596 patients) were analyzed. In the DIDO time ≤30 and >30 min groups, the primary endpoint (i.e., in-hospital or 30-day mortality) occurred for 51 of 1,794 (2.8%) and 831 of 13,802 (6.0%) patients, respectively. The incidence of the primary endpoint was significantly lower in the DIDO time ≤30 min group (odds ratio 0.45; 95% confidence interval 0.34-0.60). Conclusions: Our findings suggest that a DIDO time ≤30 min is associated with a lower short-term mortality rate. However, further larger systematic reviews and meta-analyses are needed to validate our findings.

Cluster Randomized Trial of Duration of Cooling in Targeted Temperature Management After Resuscitation for Cardiac Arrest.

Background: The 2020 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care recommend that comatose patients with return of spontaneous circulation after cardiac arrest have targeted temperature management (TTM). However, the duration of TTM remains to be elucidated. Methods and Results: We conducted a cluster randomized trial in 10 hospitals to compare 12-24 vs. 36 h of cooling in patients with cardiac arrest who received TTM. The primary outcome was the incidence, within 1 month, of complications including bleeding requiring transfusion, infection, arrhythmias, decreasing blood pressure, shivering, convulsions, and major adverse cardiovascular events. Secondary outcomes were mortality and favorable neurological outcome (Cerebral Performance Categories 1-2) at 3 months. Random-effects models with clustered effects were used to calculate risk ratios (RR). Data of 185 patients were analyzed (12- to 24-h group, n=100 in 5 hospitals; 36-h group, n=85 in 5 hospitals). The incidence of complications within 1 month did not differ between the 2 groups (40% vs. 34%; RR 1.04, 95% confidence interval [CI] 0.67-1.61, P=0.860). Favorable neurological outcomes at 3 months were comparable between the 2 groups (64% vs. 62%; RR 0.91, 95% CI 0.72-1.14, P=0.387). Conclusions: TTM at 34℃ for 12-24 h did not significantly reduce the incidence of complications. This study did not show superiority of TTM at 34℃ for 12-24 h for neurologic outcomes.

Institutional Characteristics and Prognosis of Acute Myocardial Infarction With Cardiogenic Shock in Japan　- Analysis From the JROAD/JROAD-DPC Database.

BACKGROUND: The high mortality of acute myocardial infarction (AMI) with cardiogenic shock (i.e., Killip class IV AMI) remains a challenge in emergency cardiovascular care. This study aimed to examine institutional factors, including the number of JCS board-certified members, that are independently associated with the prognosis of Killip class IV AMI patients.Methods and Results:In the Japanese registry of all cardiac and vascular diseases-diagnosis procedure combination (JROAD-DPC) database (years 2012-2016), the 30-day mortality of Killip class IV AMI patients (n=21,823) was 42.3%. Multivariate analysis identified age, female sex, admission by ambulance, deep coma, and cardiac arrest as patient factors that were independently associated with higher 30-day mortality, and the numbers of JCS board-certified members and of intra-aortic balloon pumping (IABP) cases per year as institutional factors that were independently associated with lower mortality in Killip class IV patients, although IABP was associated with higher mortality in Killip classes I-III patients. Among hospitals with the highest quartile (≥9 JCS board-certified members), the 30-day mortality of Killip class IV patients was 37.4%. CONCLUSIONS: A higher numbers of JCS board-certified members was associated with better survival of Killip class IV AMI patients. This finding may provide a clue to optimizing local emergency medical services for better management of AMI patients in Japan.

Clinical characteristics and prognostic factors in acute coronary syndrome patients complicated with cardiogenic shock in Japan: analysis from the Japanese Circulation Society Cardiovascular Shock Registry.

Cardiogenic shock frequently leads to death even with intensive treatment. Although the leading cause of cardiogenic shock is acute coronary syndrome (ACS), the clinical characteristics and the prognosis of ACS with cardiogenic shock in the present era still remain to be elucidated. We analyzed clinical characteristics and predictors of 30-day mortality in ACS with cardiogenic shock in Japan. The Japanese Circulation Society Cardiovascular Shock registry was a prospective, observational, multicenter, cohort study. Between May 2012 and June 2014, 495 ACS patients with cardiogenic shock were analyzed. The primary endpoint was 30-day all-cause mortality. The median [interquartile range; IQR] age was 71.0 [63.0, 80.0] years. The median [IQR] value of systolic blood pressure (SBP) and heart rate were 75.0 [50.0, 86.5] mm Hg and 65.0 [38.0, 98.0] bpm, respectively. Multivariable analysis showed an odds ratio (OR) of 4.76 (confidence intervals; CI 1.97-11.5, p < 0.001) in the lowest SBP category (< 50 mm Hg) for SBP ≥ 90 mm Hg. Moreover, age per 10 years increase (OR 1.38, CI 1.18-1.61, p = 0.002), deep coma (OR 3.49, CI 1.94-6.34, p < 0.001), congestive heart failure (OR 3.81, CI 2.04-7.59, p < 0.001) and left main trunk disease (LMTD) (OR 2.81, CI 1.55-5.10, p < 0.001) were independent predictors. Severe hypotension, older age, deep coma, congestive heart failure, and LMTD were independent unfavorable factors in ACS complicated by cardiogenic shock in Japan. A prompt assessment of high-risk patients referring to those predictors in emergency room could lead to appropriate treatment without delay.

Preparedness for rapid veno-venous extracorporeal membrane oxygenation introduction for pediatric severe acute respiratory distress syndrome: a case report.

CASE: Previous research has suggested that venovenous extracorporeal membrane oxygenation (vvECMO) is useful for patients refractory to conventional therapy. We report a pediatric case of influenza A(H1N1)pdm09 infection with a good outcome following rapid initiation of vvECMO.This patient was a 13-year-old boy with severe acute respiratory distress syndrome due to influenza virus. Severe acute respiratory distress syndrome according to the Berlin definition, Murray score of 3.3, and severe air leak syndrome were found. OUTCOME: Puncture for the cannula began 67 min after admission, and vvECMO management was rapidly initiated within 90 min after admission. Introduction of vvECMO required 23 min to complete. The patient was weaned from vvECMO on day 5 and he was discharged home without any complication. CONCLUSION: It is essential to prepare a system that enables the rapid introduction of vvECMO for children in the emergency center.

Two cases with intra-aortic balloon pumping use for severe septic cardiomyopathy.

Cases: Septic cardiomyopathy is defined as a reversible left ventricular systolic dysfunction. Patients with severe septic cardiomyopathy have a high mortality rate, even if they receive conventional therapy. For those patients, previous reports showed intra-aortic balloon pump (IABP) efficacy. We report two rare cases with IABP introduction leading them to drastic improvement, and survival from severe septic cardiomyopathy. Case 1 is a 78-year-old woman diagnosed with renal calculus pyelonephritis, septic shock, and septic cardiomyopathy. Case 2 is a 62-year-old man diagnosed with pneumonia, septic shock, and septic cardiomyopathy. Outcome: In both cases, despite conventional therapy for cardiomyopathy, including high-dose catecholamine therapy, shock was not reversed, and the IABP was inserted. Circulatory status was improved after the introduction of the IABP. Conclusion: Our findings suggest that an IABP can be useful for salvaging patients with septic cardiomyopathy who do not respond to conventional therapy.

Prolonged Fever After ST-Segment Elevation Myocardial Infarction and Long-Term Cardiac Outcomes.

BACKGROUND: The biphasic inflammation after ST-segment elevation myocardial infarction (STEMI) plays an important role in myocardial healing and progression of systemic atherosclerosis. The purpose of this study is to investigate the impact of fever during the first and second phases of post-STEMI inflammation on long-term cardiac outcomes. METHODS AND RESULTS: A total of 550 patients with STEMI were enrolled in this study. Axillary body temperature (BT) was measured and maximum BTs were determined for the first (within 3 days: max-BT1-3d) and second (from 4 to 10 days after admission: max-BT4-10d) phases, respectively. Patients were followed for cardiac events (cardiovascular death, acute coronary syndrome, and rehospitalization for heart failure) for a median 5.3 years. During the follow-up period, 80 patients experienced cardiac events. A high max-BT4-10d was strongly associated with long-term cardiac events (hazard ratio, 95% CI) for a 1°C increase in the max-BT4-10d: 2.834 (2.017-3.828), P<0.0001, whereas the max-BT1-3d was not associated with cardiac events (1.136 [0.731-1.742], P=0.57). Even after adjustment for coronary risk factors, estimated glomerular filtration rate, infarct size, pericardial effusion, and medications on discharge, fever during the second phase (max-BT4-10d ≥37.1°C) was significantly associated with future cardiac events (hazard ratio [95% CI] 2.900 [1.710-5.143], P<0.0001). CONCLUSIONS: Fever during the second phase but not the first phase of post-STEMI inflammation was a strong associated factor with worse long-term cardiac outcomes in patients after STEMI, suggesting the need to consider the optimal timing for anti-inflammatory strategies after STEMI.

Association between gait speed as a measure of frailty and risk of cardiovascular events after myocardial infarction.

OBJECTIVES: This study sought to determine the additional clinical value of gait speed to Framingham risk score (FRS), cardiac function, and comorbid conditions in predicting cardiovascular events in patients with ST-segment elevation myocardial infarction. BACKGROUND: There is growing evidence that gait speed is inversely associated with all-cause mortality, particularly cardiovascular mortality, among the elderly. METHODS: We undertook a single-center prospective observational study of gait speed in 472 patients with ST-segment elevation myocardial infarction in Japan, between 2001 and 2008. Gait speeds were measured using a 200-m course before discharge in all patients, and we followed up cardiovascular events, which consist of cardiovascular deaths, nonfatal myocardial infarctions, and nonfatal ischemic strokes. RESULTS: During the 2,596 person-years of follow-up, 83 patients (17.6%) experienced cardiovascular events. Cardiovascular events increased across decreasing tertiles of gait speed (fastest tertile: n = 5, 3.2%; middle tertile: n = 20, 12.6%; slowest tertile, n = 58, 36.7%). By multiple adjusted Cox proportional hazards analysis, gait speed was a significant and independent predictor of cardiovascular events (hazard ratio for increasing 0.1 m/s of gait speed: 0.71, 95% confidence interval [CI]: 0.63 to 0.81, p < 0.001). The addition of gait speed to the model incorporating FRS, B-type natriuretic peptide levels, and comorbidity index improved reclassification (net reclassification index: 32.8%, 95% CI: 17.4 to 48.3, p < 0.001) and the C-statistics with a reasonable global fit and calibration (C-statistics: from 0.703 [95% CI: 0.636 to 0.763] to 0.786 [95% CI: 0.738 to 0.829]). CONCLUSIONS: Among patients with ST-segment elevation myocardial infarction, slow gait speed was significantly associated with an increased risk of cardiovascular events. (Gait Speed for Predicting Cardiovascular Events After Myocardial Infarction; NCT01484158).

Percutaneous cardiopulmonary support in pulmonary embolism with cardiac arrest.

OBJECTIVE: To assess the role of percutaneous cardiopulmonary support (PCPS) for the resuscitation of patients with massive pulmonary embolism (PE) with circulatory collapse. We also compared outcomes for PCPS between patients with massive PE with circulatory collapse and patients with AMI with cardiogenic shock. BACKGROUND: The effectiveness of PCPS for acute myocardial infarction (AMI) complicated with cardiogenic shock has been reported, but there are few reports on the use of PCPS for massive PE with circulatory collapse. METHOD: We studied 12 consecutive patients with massive PE and 16 patients with AMI, who required PCPS for resuscitation either during cardiopulmonary resuscitation (CPR) or after successful CPR. RESULTS: Twelve patients with PE and 16 patients with AMI were identified. There were no differences in age, the Acute Physiology, Age and Chronic Health Evaluation II (APACHE II) score at admission, rate of cardiac arrest on arrival, and time from first circulatory collapse to PCPS between the two groups. However, the proportion of men with PE (33%) was smaller than those with AMI (87%, p<0.05). The duration of PCPS was shorter in PE (38 h) compared with AMI (83 h, p=0.051) patients. The proportion of patients successfully weaned from PCPS (100% vs. 37.5%, p<0.01), survival rate at discharge (83.3% vs. 12.5%, p<0.001) and good neurological outcome (58.3% vs. 6.3%, p=0.004) was significantly higher for PE compared to AMI patients. CONCLUSION: In our small case series, percutaneous cardiopulmonary support (PCPS) had a life saving role in patients with massive PE and cardiac arrest. PCPS was also more effective in patients with massive PE with cardiac arrest than in patients with AMI and cardiac arrest.

High QRS score on admission strongly predicts impaired myocardial reperfusion in patients with a first anterior acute myocardial infarction.

BACKGROUND: In patients with acute myocardial infarction (AMI), QRS score at presentation electrocardiogram (ECG) may reflect the evolutionary stage of the infarction and allow one to predict the degree of myocardial reperfusion potentially achievable by reperfusion therapy. METHODS AND RESULTS: The relationship between QRS score on admission ECG and myocardial blush grade, an angiographic marker of myocardial reperfusion, was examined in 416 patients with a first anterior AMI who received reperfusion therapy within 6h after symptom onset. Patients were classified into 3 groups according to QRS score: 0 or 1 (n=102), 2-4 (n=228), and ≥5 (n=86). Higher QRS scores were associated with a longer time to admission, a greater ST-segment elevation, a higher frequency of impaired initial and final culprit coronary vessel flow, a higher peak creatine kinase level, and a higher frequency of impaired myocardial reperfusion as defined by myocardial blush grade 0/1 on the final angiogram. Multivariate analysis showed that a high QRS score ≥5 was the strongest predictor of impaired myocardial reperfusion (odds ratio 20.3, P<0.001). These findings were similar when the data were stratified according to time to admission (≤2h, >2h). CONCLUSIONS: In patients with a first anterior AMI treated by reperfusion therapy, admission high QRS score ≥5 strongly predicts impaired myocardial reperfusion, even when presentation is early (≤2h).

Impact of high-responsiveness to dual antiplatelet therapy on bleeding complications in patients receiving drug-eluting stents.

BACKGROUND: Few studies have examined whether high-responsiveness to antiplatelet therapy is associated with an increased risk of bleeding in patients receiving dual antiplatelet therapy. METHODS AND RESULTS: Elective drug-eluting stent implantation was performed in 184 patients treated with aspirin and a thienopyridine (200 mg/day of ticlopidine or 75 mg/day of clopidogrel). The subjects were divided into 3 groups according to post-treatment platelet reactivity before stenting as measured by the response to adenosine diphosphate: the 1(st) quartile group was defined as high-responders, the 4(th) as low-responders, and the other 2 quartiles as middle-responders. Major bleeding occurred more frequently in high-responders than in middle- or low-responders during an average of 16 months' follow-up (15 vs 4, 2%, P=0.02). High-responsiveness was the independent predictor of major bleeding (odds ratio 4.26, P=0.03). Adverse cardiac events were less frequent in high- and middle-responders than in low-responders (24, 16 vs 37%, P=0.02). Middle-responders had better net clinical outcomes, defined as the sum of major bleeding and adverse cardiac events, than did high- or low-responders (21 vs 39, 39%, P=0.02). CONCLUSIONS: In the present study high-responsiveness to antiplatelet therapy was associated with an increased risk of bleeding with no reduction in adverse cardiac events. Measuring platelet reactivity may be useful for risk stratification according to bleeding complications, as well as adverse cardiac events, in patients treated with drug-eluting stents.