José P.S. Henriques

A systematic review and meta-analysis of intra-aortic balloon pump therapy in ST-elevation myocardial infarction : should we change the guidelines?

Aims Intra-aortic balloon counterpulsation (IABP) in ST-segment elevation myocardial infarction (STEMI) with cardiogenic shock is strongly recommended (class IB) in the current guidelines. We performed meta-analyses to evaluate the evidence for IABP in STEMI with and without cardiogenic shock. Methods and results Medical literature databases were scrutinized to identify randomized trials comparing IABP with no IABP in STEMI. In absence of randomized trials, cohort studies of IABP in STEMI with cardiogenic shock were identified. Two separate meta-analyses were performed respectively. The first meta-analysis included seven randomized trials (n = 1009) of STEMI. IABP showed neither a 30-day survival benefit nor improved left ventricular ejection fraction, while being associated with significantly higher stroke and bleeding rates. The second meta-analysis included nine cohorts of STEMI patients with cardiogenic shock (n = 10529). In patients treated with thrombolysis, IABP was associated with an 18% [95% confidence interval (CI), 16-20%; P < 0.0001] decrease in 30 day mortality, albeit with significantly higher revascularization rates compared to patients without support. Contrariwise, in patients treated with primary percutaneous coronary intervention, IABP was associated with a 6% (95% CI, 3-10%; P < 0.0008) increase in 30 day mortality. Conclusion The pooled randomized data do not support IABP in patients with high-risk STEMI. The meta-analysis of cohort studies in the setting of STEMI complicated by cardiogenic shock supported IABP therapy adjunctive to thrombolysis. In contrast, the observational data did not support IABP therapy adjunctive to primary PCI. All available observational data concerning IABP therapy in the setting of cardiogenic shock is importantly hampered by bias and confounding. There is insufficient evidence endorsing the current guideline recommendation for the use of IABP therapy in the setting of STEMI complicated by cardiogenic shock. Our meta-analyses challenge the current guideline recommendations.

Exenatide Reduces Infarct Size and Improves Cardiac Function in a Porcine Model of Ischemia and Reperfusion Injury

OBJECTIVES This study sought to examine whether exenatide is capable of reducing myocardial infarct size. BACKGROUND Exenatide is a glucagon-like peptide (GLP)-1 analogue with insulinotropic and insulinomimetic properties. Because insulin and GLP-1 have been described as reducing apoptosis, exenatide might confer cardioprotection after acute myocardial infarction (MI). METHODS Pigs were randomized to exenatide or phosphate-buffered saline (PBS) treatment after 75 min of coronary artery ligation and subsequent reperfusion. Infarct size was assessed with Evans Blue (Sigma-Aldrich, St. Louis, Missouri) and triphenyltetrazolium chloride. Cardiac function was measured with epicardial ultrasound and conductance catheter-based pressure-volume loops. Western blotting, histology, and activity assays were performed to determine markers of apoptosis/survival and oxidative stress. RESULTS Exenatide reduced myocardial infarct size (32.7 +/- 6.4% vs. 53.6 +/- 3.9%; p = 0.031) and prevented deterioration of systolic and diastolic cardiac function (systolic wall thickening: 47.3 +/- 6.3% vs. 8.1 +/- 1.9%, p < 0.001; myocardial stiffness: 0.12 +/- 0.06 mm Hg/ml vs. 0.22 +/- 0.07 mm Hg/ml; p = 0.004). After exenatide treatment, myocardial phosphorylated Akt and Bcl-2 expression levels were higher compared with those after PBS treatment, and active caspase 3 expression was lower. In addition, fewer cells were terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling-positive. In addition, nuclear oxidative stress as assessed with an 8-hydroxydeoxyguanosine staining was reduced in the exenatide treatment arm, and superoxide dismutase activity and catalase activity were increased. Serum insulin levels increased after exenatide treatment, without affecting glucose levels. CONCLUSIONS These data identify exenatide as a potentially effective compound to reduce infarct size in adjunction to reperfusion therapy in patients with acute MI.

Angiographic Assessment of Reperfusion in Acute Myocardial Infarction by Myocardial Blush Grade

Background—Angiographic successful reperfusion in acute myocardial infarction has been defined as TIMI 3 flow. However, TIMI 3 flow does not always result in effective myocardial reperfusion. Myocardial blush grade (MBG) is an angiographic measure of myocardial perfusion. We hypothesized that optimal angiographic reperfusion is defined by TIMI 3 flow and MBG 2 or 3. Methods and Results—In 924 consecutive patients with TIMI 3 flow after angioplasty for acute myocardial infarction, we prospectively studied the value of MBG. End points were death, MACE, enzymatic infarct size, and residual left ventricular ejection fraction. Follow-up was 16±11 months. Of the 924 patients, 101 (11%) patients had MBG 0 or 1. Mortality was significantly higher in patients with MBG 0 or 1 compared with patients with MBG 2 or 3 (relative risk, 4.7; 95% CI, 2.3 to 9.5;P <0.001). The combined incidence of MACE was higher in patients with MBG 0 or 1 compared with patients with MBG 2 or 3 (relative risk, 1.8; 95% CI, 1.1 to 2.8;P =0.009). Enzymatic infarct size was larger (1437±2388 versus 809±1672, P =0.001) and left ventricular ejection fraction was lower (37.7±10.6 versus 43.8±11.1, P <0.001) in patients with MBG 0 or 1 compared with patients with MBG 2 or 3. Conclusions—MBG is a strong angiographic predictor of mortality in patients with TIMI 3 flow after primary angioplasty. Enzymatic infarct size is larger and residual left ventricular ejection fraction is lower in patients with MBG 0 or 1 compared with MBG 2 or 3. Angiographic definition of successful reperfusion should include both TIMI 3 flow as well as MBG 2 or 3.

A Prospective, Randomized Clinical Trial of Hemodynamic Support With Impella 2.5 Versus Intra-Aortic Balloon Pump in Patients Undergoing High-Risk Percutaneous Coronary Intervention The PROTECT II Study

Background— Although coronary artery bypass grafting is generally preferred in symptomatic patients with severe, complex multivessel, or left main disease, some patients present with clinical features that make coronary artery bypass grafting clinically unattractive. Percutaneous coronary intervention with hemodynamic support may be feasible for these patients. Currently, there is no systematic comparative evaluation of hemodynamic support devices for this indication. Methods and Results— We randomly assigned 452 symptomatic patients with complex 3-vessel disease or unprotected left main coronary artery disease and severely depressed left ventricular function to intra-aortic balloon pump (IABP) (n=226) or Impella 2.5 (n=226) support during nonemergent high-risk percutaneous coronary intervention. The primary end point was the 30-day incidence of major adverse events. A 90-day follow-up was required, as well, by protocol. Impella 2.5 provided superior hemodynamic support in comparison with IABP, with maximal decrease in cardiac power output from baseline of −0.04±0.24 W in comparison with −0.14±0.27 W for IABP (P=0.001). The primary end point (30-day major adverse events) was not statistically different between groups: 35.1% for Impella 2.5 versus 40.1% for IABP, P=0.227 in the intent-to-treat population and 34.3% versus 42.2%, P=0.092 in the per protocol population. At 90 days, a strong trend toward decreased major adverse events was observed in Impella 2.5–supported patients in comparison with IABP: 40.6% versus 49.3%, P=0.066 in the intent-to-treat population and 40.0% versus 51.0%, P=0.023 in the per protocol population, respectively. Conclusions— The 30-day incidence of major adverse events was not different for patients with IABP or Impella 2.5 hemodynamic support. However, trends for improved outcomes were observed for Impella 2.5–supported patients at 90 days. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00562016.

Familial Sudden Death Is an Important Risk Factor for Primary Ventricular Fibrillation A Case-Control Study in Acute Myocardial Infarction Patients

Background— Primary ventricular fibrillation (VF) accounts for the majority of deaths during the acute phase of myocardial infarction. Identification of patients at risk for primary VF remains very poor. Methods and Results— We performed a case-control study in patients with a first ST-elevation myocardial infarction (STEMI) to identify independent risk factors for primary VF. A total of 330 primary VF survivors (cases) and 372 controls were included; patients with earlier infarcts or signs of structural heart disease were excluded. Baseline characteristics, including age, gender, drug use, and ECG parameters registered well before the index infarction, as well as medical history, were not different. Infarct size and location, culprit coronary artery, and presence of multivessel disease were similar between groups. Analysis of ECGs performed at hospital admission for the index STEMI revealed that cumulative ST deviation was significantly higher among cases (OR per 10-mm ST deviation 1.59, 95% CI 1.25 to 2.02). Analysis of medical histories among parents and siblings showed that the prevalence of cardiovascular disease was similar between cases and controls (73.1% and 73.0%, respectively); however, familial sudden death occurred significantly more frequently among cases than controls (43.1% and 25.1%, respectively; OR 2.72, 95% CI 1.84 to 4.03). Conclusions— In a population of STEMI patients, the risk of primary VF is determined by cumulative ST deviation and family history of sudden death.

Plaque Instability Frequently Occurs Days or Weeks Before Occlusive Coronary Thrombosis A Pathological Thrombectomy Study in Primary Percutaneous Coronary Intervention

Background—Acute ST-elevation myocardial infarction (STEMI) is caused by sudden occlusive coronary thrombosis, after plaque disruption; however, a considerable time interval between plaque disturbance and the onset of symptoms has been suggested. We therefore studied the age of intracoronary thrombi, aspirated during angioplasty in patients with acute STEMI. Methods and Results—Percutaneous intracoronary thrombectomy during angioplasty was performed in 211 consecutive STEMI patients within 6 hours after onset of anginal symptoms. The aspirated material was histologically screened on thrombus and plaque components, and thrombus age was classified as fresh (<1 day), lytic thrombus (1 to 5 days), and organized thrombus (>5 days). In all patients, intracoronary-derived material was retrieved in the filter of the collection bottle. Thrombus was identified in 199 (95%) of 211 patients. In 12 patients (5%), only plaque components were identified, and in 85 patients (41%), both thrombus and plaque material were aspirated. In 18 (9%) of 199 patients, the thrombus was organized, and in 70 patients (35%), the thrombus showed lytic changes, whereas in 98 (49%), a completely fresh thrombus was found. In 14 (7%) of 199 patients, the thrombus showed combined features of both fresh thrombus and organized thrombus. Conclusions—In at least 50% of patients with acute STEMI, coronary thrombi were days or weeks old. This indicates that sudden coronary occlusion is often preceded by a variable period of plaque instability and thrombus formation, initiated days or weeks before onset of symptoms.

A prospective feasibility trial investigating the use of the Impella 2.5 system in patients undergoing high-risk percutaneous coronary intervention (The PROTECT I Trial): initial U.S. experience

OBJECTIVES We sought to evaluate the safety and feasibility of the Impella 2.5 system (Abiomed Inc., Danvers, Massachusetts) in patients undergoing high-risk percutaneous coronary intervention (PCI). BACKGROUND The Impella 2.5 is a miniaturized percutaneous cardiac assist device, which provides up to 2.5 l/min forward flow from the left ventricle into the systemic circulation. METHODS In a prospective, multicenter study, 20 patients underwent high-risk PCI with minimally invasive circulatory support employing the Impella 2.5 system. All patients had poor left ventricular function (ejection fraction <or=35%) and underwent PCI on an unprotected left main coronary artery or last patent coronary conduit. Patients with recent ST-segment elevation myocardial infarction or cardiogenic shock were excluded. The primary safety end point was the incidence of major adverse cardiac events at 30 days. The primary efficacy end point was freedom from hemodynamic compromise during PCI (defined as a decrease in mean arterial pressure below 60 mm Hg for >10 min). RESULTS The Impella 2.5 device was implanted successfully in all patients. The mean duration of circulatory support was 1.7 +/- 0.6 h (range: 0.4 to 2.5 h). Mean pump flow during PCI was 2.2 +/- 0.3 l/min. At 30 days, the incidence of major adverse cardiac events was 20% (2 patients had a periprocedural myocardial infarction; 2 patients died at days 12 and 14). There was no evidence of aortic valve injury, cardiac perforation, or limb ischemia. Two patients (10%) developed mild, transient hemolysis without clinical sequelae. None of the patients developed hemodynamic compromise during PCI. CONCLUSIONS The Impella 2.5 system is safe, easy to implant, and provides excellent hemodynamic support during high-risk PCI. (The PROTECT I Trial; NCT00534859).

Long-Term Outcome of Percutaneous Coronary Intervention for Chronic Total Occlusions

OBJECTIVES The aim of this study was to evaluate long-term clinical outcomes after percutaneous coronary intervention (PCI) for chronic total occlusions (CTO). BACKGROUND Despite technical advancements, there is a paucity of data on long-term outcomes after PCI of CTO. METHODS We evaluated long-term clinical outcomes in 1,791 patients who underwent PCI of 1,852 CTO at 3 tertiary care centers in the United States, South Korea, and Italy between 1998 and 2007. Median follow-up was 2.9 years (interquartile range: 1.5 to 4.6 years). RESULTS Procedural success was obtained in 1,226 (68%) patients. Stents were implanted in 1,160 patients (95%); 396 patients (34%) received bare-metal stents (BMS), and 764 patients (66%) received drug-eluting stents (DES). After multivariable analysis, successful CTO PCI was an independent predictor of a lower cardiac mortality (hazard ratio [HR]: 0.40, 95% confidence interval [CI]: 0.21 to 0.75, p < 0.01) and reduced need for coronary artery bypass graft surgery (HR: 0.21, 95% CI: 0.13 to 0.40, p < 0.01); it also correlated with a strong trend toward lower all-cause mortality (HR: 0.63, 95% CI: 0.40 to 1.00, p = 0.05) at 5-year follow-up. Among patients who underwent stent implantation, treatment with DES rather than BMS resulted in less target vessel revascularization at long-term follow-up (17.2% vs. 31.1%, p < 0.01); definite/probable stent thrombosis rates were similar (DES 1.7%, BMS 2.3%, p = 0.58). Within the DES subgroup, patients treated with paclitaxel-eluting stents and sirolimus-eluting stents had similar clinical outcomes. CONCLUSIONS Successful CTO PCI is associated with reduced long-term cardiac mortality and need for coronary artery bypass graft surgery. Treatment of CTO with DES rather than BMS is associated with a significant reduction in target vessel revascularization with similar rates of stent thrombosis. Paclitaxel-eluting stents and sirolimus-eluting stents had similar long-term safety and efficacy outcomes.

Physiological Basis and Long-Term Clinical Outcome of Discordance Between Fractional Flow Reserve and Coronary Flow Velocity Reserve in Coronary Stenoses of Intermediate Severity

Background—Discordance between fractional flow reserve (FFR) and coronary flow velocity reserve (CFVR) may reflect important coronary pathophysiology but usually remains unnoticed in clinical practice. We evaluated the physiological basis and clinical outcome associated with FFR/CFVR discordance. Methods and Results—We studied 157 intermediate coronary stenoses in 157 patients, evaluated by FFR and CFVR between April 1997 and September 2006 in which revascularization was deferred. Long-term follow-up was performed to document the occurrence of major adverse cardiac events: cardiac death, myocardial infarction, or target vessel revascularization. Discordance between FFR and CFVR occurred in 31% and 37% of stenoses at the 0.75, and 0.80 FFR cut-off value, respectively, and was characterized by microvascular resistances during basal and hyperemic conditions. Follow-up duration amounted to 11.7 years (Q1–Q3, 9.9–13.3 years). Compared with concordant normal results of FFR and CFVR, a normal FFR with an abnormal CFVR was associated with significantly increased major adverse cardiac events rate throughout 10 years of follow-up, regardless of the FFR cut-off applied. In contrast, an abnormal FFR with a normal CFVR was associated with equivalent clinical outcome compared with concordant normal results: ⩽3 years when FFR <0.75 was depicted abnormal and throughout 10 years of follow-up when FFR ⩽0.80 was depicted abnormal. Conclusions—Discordance of CFVR with FFR originates from the involvement of the coronary microvasculature. Importantly, the risk for major adverse cardiac events associated with FFR/CFVR discordance is mainly attributable to stenoses where CFVR is abnormal. This emphasizes the requirement of intracoronary flow assessment in addition to coronary pressure for optimal risk stratification in stable coronary artery disease.

Outcome of primary angioplasty for acute myocardial infarction during routine duty hours versus during off-hours

OBJECTIVES We sought to investigate the impact of circadian patterns in the onset of acute myocardial infarction (AMI) on the practice of primary angioplasty. BACKGROUND A circadian variation in the time of onset of AMI with a peak in the morning hours has been described. METHODS We studied 1,702 consecutive patients with acute ST-segment elevation myocardial infarction treated with primary angioplasty. We observed circadian variation in frequency of symptom onset, hospital admission, and first balloon inflation. Circadian patterns of symptom onset, hospital admission, and balloon inflation are similar. RESULTS A majority of patients have symptom onset (53%), hospital admission (53%), and first balloon inflation (52%) during routine duty hours (0800 to 1800 h). There were no differences in baseline clinical characteristics or treatment delays between routine duty hours and off-hours patients. Hospital admission between 0800 and 1800 was associated with an angioplasty failure rate of 3.8%, compared with 6.9% between 1800 and 0800, p < 0.01. Thirty-day mortality was 1.9% in patients with hospital admission between 0800 and 1800, compared with 4.2% in patients with hospital admission between 1800 and 0800, p < 0.01. CONCLUSIONS Circadian variations may have a profound effect on the practice of primary angioplasty. A majority of patients are treated during routine duty hours. Patients treated during off-hours have a higher incidence of failed angioplasty and consequently a worse clinical outcome than patients treated during routine duty hours.