Mauricio G. Cohen

A Comparison of Low-Molecular-Weight Heparin with Unfractionated Heparin for Unstable Coronary Artery Disease

BACKGROUND Antithrombotic therapy with heparin plus aspirin reduces the rate of ischemic events in patients with unstable coronary artery disease. Low-molecular-weight heparin has a more predictable anticoagulant effect than standard unfractionated heparin, is easier to administer, and does not require monitoring. METHODS In a double-blind, placebo-controlled study, we randomly assigned 3171 patients with angina at rest or non-Q-wave myocardial infarction to receive either 1 mg of enoxaparin (low-molecular-weight heparin) per kilogram of body weight, administered subcutaneously twice daily, or continuous intravenous unfractionated heparin. Therapy was continued for a minimum of 48 hours to a maximum of 8 days, and we collected data on important coronary end points over a period of 30 days. RESULTS At 14 days the risk of death, myocardial infarction, or recurrent angina was significantly lower in the patients assigned to enoxaparin than in those assigned to unfractionated heparin (16.6 percent vs. 19.8 percent, P=0.019). At 30 days, the risk of this composite end point remained significantly lower in the enoxaparin group (19.8 percent vs. 23.3 percent, P=0.016). The need for revascularization procedures at 30 days was also significantly less frequent in the patients assigned to enoxaparin (27.1 percent vs. 32.2 percent, P=0.001). The 30-day incidence of major bleeding complications was 6.5 percent in the enoxaparin group and 7.0 percent in the unfractionated-heparin group, but the incidence of bleeding overall was significantly higher in the enoxaparin group (18.4 percent vs. 14.2 percent, P=0.001), primarily because of ecchymoses at injection sites. CONCLUSIONS Antithrombotic therapy with enoxaparin plus aspirin was more effective than unfractionated heparin plus aspirin in reducing the incidence of ischemic events in patients with unstable angina or non-Q-wave myocardial infarction in the early phase. This benefit of enoxaparin was achieved with an increase in minor but not in major bleeding.

The Transradial Approach to Percutaneous Coronary Intervention: Historical Perspective, Current Concepts, and Future Directions

Periprocedural bleeding complications after percutaneous coronary intervention (PCI) are associated with increased short- and long-term morbidity and mortality. Although clinical trials have primarily assessed pharmacological strategies for reducing bleeding risk, there is a mounting body of evidence suggesting that adoption of a transradial rather than a transfemoral approach to PCI may permit greater reductions in bleeding risk than have been achieved with pharmacological strategies alone. However, despite a long history of use, a lack of widespread uptake by physicians coupled with the technological limitations of available devices has in the past confined transradial PCI to the status of a niche procedure, and many operators lack experience in this technique. In this review, we examine the history of the transradial approach to PCI and discuss some of the circumstances that have hitherto limited its appeal. We then review the current state of the peer-reviewed literature supporting its use and summarize the unresolved issues affecting broader application of this technique, including lack of operator familiarity and an insufficient evidence base for guiding practice. Finally, we describe potential directions for future investigation in the transradial realm.

Adoption of Radial Access and Comparison of Outcomes to Femoral Access in Percutaneous Coronary Intervention An Updated Report from the National Cardiovascular Data Registry (2007–2012)

Background— Radial access for percutaneous coronary intervention (r-PCI) is associated with reduced vascular complications; however, previous reports have shown that <2% of percutaneous coronary intervention (PCI) procedures in the United States are performed via the radial approach. Our aims were to evaluate temporal trends in r-PCI and compare procedural outcomes between r-PCI and transfemoral PCI. Methods and Results— We conducted a retrospective cohort study from the CathPCI registry (n=2 820 874 procedures from 1381 sites) between January 2007 and September 2012. Multivariable logistic regression models were used to evaluate the adjusted association between r-PCI and bleeding, vascular complications, and procedural success, using transfemoral PCI as the reference. Outcomes in high-risk subgroups such as age ≥75 years, women, and patients with acute coronary syndrome were also examined. The proportion of r-PCI procedures increased from 1.2% in quarter 1 2007 to 16.1% in quarter 3 2012 and accounted for 6.3% of total procedures from 2007 to 2012 (n=178 643). After multivariable adjustment, r-PCI use in the studied cohort of patients was associated with lower risk of bleeding (adjusted odds ratio, 0.51; 95% confidence interval, 0.49–0.54) and lower risk of vascular complications (adjusted odds ratio, 0.39; 95% confidence interval, 0.31–0.50) in comparison with transfemoral PCI. The reduction in bleeding and vascular complications was consistent across important subgroups of age, sex, and clinical presentation. Conclusions— There has been increasing adoption of r-PCI in the United States. Transradial PCI now accounts for 1 of 6 PCIs performed in contemporary clinical practice. In comparison with traditional femoral access, transradial PCI is associated with lower vascular and bleeding complication rates. # Clinical Perspective {#article-title-25}Background— Radial access for percutaneous coronary intervention (r-PCI) is associated with reduced vascular complications; however, previous reports have shown that <2% of percutaneous coronary intervention (PCI) procedures in the United States are performed via the radial approach. Our aims were to evaluate temporal trends in r-PCI and compare procedural outcomes between r-PCI and transfemoral PCI. Methods and Results— We conducted a retrospective cohort study from the CathPCI registry (n=2 820 874 procedures from 1381 sites) between January 2007 and September 2012. Multivariable logistic regression models were used to evaluate the adjusted association between r-PCI and bleeding, vascular complications, and procedural success, using transfemoral PCI as the reference. Outcomes in high-risk subgroups such as age ≥75 years, women, and patients with acute coronary syndrome were also examined. The proportion of r-PCI procedures increased from 1.2% in quarter 1 2007 to 16.1% in quarter 3 2012 and accounted for 6.3% of total procedures from 2007 to 2012 (n=178 643). After multivariable adjustment, r-PCI use in the studied cohort of patients was associated with lower risk of bleeding (adjusted odds ratio, 0.51; 95% confidence interval, 0.49–0.54) and lower risk of vascular complications (adjusted odds ratio, 0.39; 95% confidence interval, 0.31–0.50) in comparison with transfemoral PCI. The reduction in bleeding and vascular complications was consistent across important subgroups of age, sex, and clinical presentation. Conclusions— There has been increasing adoption of r-PCI in the United States. Transradial PCI now accounts for 1 of 6 PCIs performed in contemporary clinical practice. In comparison with traditional femoral access, transradial PCI is associated with lower vascular and bleeding complication rates.

Racial variations in treatment and outcomes of black and white patients with high-risk non-ST-elevation acute coronary syndromes: insights from CRUSADE (Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes With Early Implementation of the ACC/AHA Guidelines?).

Background—Black patients with acute myocardial infarction are less likely than whites to receive coronary interventions. It is unknown whether racial disparities exist for other treatments for non–ST-segment elevation acute coronary syndromes (NSTE ACS) and how different treatments affect outcomes. Methods and Results—Using data from 400 US hospitals participating in the CRUSADE (Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes with Early Implementation of the ACC/AHA Guidelines?) National Quality Improvement Initiative, we identified black and white patients with high-risk NSTE ACS (positive cardiac markers and/or ischemic ST-segment changes). After adjustment for demographics and medical comorbidity, we compared the use of therapies recommended by the American College of Cardiology/American Heart Association guidelines for NSTE ACS and outcomes by race. Our study included 37 813 (87.3%) white and 5504 (12.7%) black patients. Black patients were younger; were more likely to have hypertension, diabetes, heart failure, and renal insufficiency; and were less likely to have insurance coverage or primary cardiology care. Black patients had a similar or higher likelihood than whites of receiving older ACS treatments such as aspirin, &bgr;-blockers, or ACE inhibitors but were significantly less likely to receive newer ACS therapies, including acute glycoprotein IIb/IIIa inhibitors, acute and discharge clopidogrel, and statin therapy at discharge. Blacks were also less likely to receive cardiac catheterization, revascularization procedures, or smoking cessation counseling. Acute risk-adjusted outcomes were similar between black and white patients. Conclusions—Black patients with NSTE ACS were less likely than whites to receive many evidence-based treatments, particularly those that are costly or newer. Longitudinal studies are needed to assess the long-term impact of these treatment disparities on clinical outcomes.

Predictive factors, management, and clinical outcomes of coronary obstruction following transcatheter aortic valve implantation: Insights from a large multicenter registry

OBJECTIVES This study sought to evaluate the main baseline and procedural characteristics, management, and clinical outcomes of patients from a large cohort of patients undergoing transcatheter aortic valve implantation (TAVI) who suffered coronary obstruction (CO). BACKGROUND Very little data exist on CO following TAVI. METHODS This multicenter registry included 44 patients who suffered symptomatic CO following TAVI of 6,688 patients (0.66%). Pre-TAVI computed tomography data was available in 28 CO patients and in a control group of 345 patients (comparisons were performed including all patients and a cohort matched 1:1 by age, sex, previous coronary artery bypass graft, transcatheter valve type, and size). RESULTS Baseline and procedural variables associated with CO were older age (p < 0.001), female sex (p < 0.001), no previous coronary artery bypass graft (p = 0.043), the use of a balloon-expandable valve (p = 0.023), and previous surgical aortic bioprosthesis (p = 0.045). The left coronary artery was the most commonly involved (88.6%). The mean left coronary artery ostia height and sinus of Valsalva diameters were lower in patients with obstruction than in control subjects (10.6 ± 2.1 mm vs. 13.4 ± 2.1 mm, p < 0.001; 28.1 ± 3.8 mm vs. 31.9 ± 4.1 mm, p < 0.001). Differences between groups remained significant after the case-matched analysis (p < 0.001 for coronary height; p = 0.01 for sinus of Valsalva diameter). Most patients presented with persistent severe hypotension (68.2%) and electrocardiographic changes (56.8%). Percutaneous coronary intervention was attempted in 75% of the cases and was successful in 81.8%. Thirty-day mortality was 40.9%. After a median follow-up of 12 (2 to 18) months, the cumulative mortality rate was 45.5%, and there were no cases of stent thrombosis or reintervention. CONCLUSIONS Symptomatic CO following TAVI was a rare but life-threatening complication that occurred more frequently in women, in patients receiving a balloon-expandable valve, and in those with a previous surgical bioprosthesis. Lower-lying coronary ostium and shallow sinus of Valsalva were associated anatomic factors, and despite successful treatment, acute and late mortality remained very high, highlighting the importance of anticipating and preventing the occurrence of this complication.

Racial and Ethnic Differences in the Treatment of Acute Myocardial Infarction Findings From the Get With The Guidelines–Coronary Artery Disease Program

Background— Racial/ethnic differences in cardiovascular care have been well documented. We sought to determine whether racial/ethnic differences in evidence-based acute myocardial infarction care persist among hospitals participating in a national quality improvement program. Methods and Results— We analyzed 142 593 acute myocardial infarction patients (121 528 whites, 10 882 blacks, and 10 183 Hispanics) at 443 hospitals participating in the Get With the Guidelines-Coronary Artery Disease (GWTG-CAD) program between January 2002 and June 2007. We examined individual and overall composite rates of defect-free care, defined as the proportion of patients receiving all eligible performance measures. In addition, we examined temporal trends in use of performance measures according to race/ethnicity by calendar quarter. Overall, individual performance measure use was high, ranging from 78% for use of angiotensin-converting enzyme inhibitors to 96% for use of aspirin at discharge. Use of each of these improved significantly over the 5 years of study. Overall, defect-free care was 80.9% for whites, 79.5% for Hispanics (adjusted odds ratio versus whites 1.00, 95% confidence interval 0.94 to 1.06, P=0.94), and 77.7% for blacks (adjusted odds ratio versus whites 0.93, 95% confidence interval 0.87 to 0.98, P=0.01). A significant gap in defect-free care was observed for blacks mostly during the first half of the study, which was no longer present during the remainder of the study. Overall, progressive improvements in defect-free care were observed regardless of race/ethnic groups. Conclusions— Among hospitals engaged in a national quality monitoring and improvement program, evidence-based care for acute myocardial infarction appeared to improve over time for patients irrespective of race/ethnicity, and differences in care by race/ethnicity care were reduced or eliminated.

Phase 1b Randomized Study of Antidote-Controlled Modulation of Factor IXa Activity in Patients With Stable Coronary Artery Disease

Background— Whether selective factor IXa inhibition produces an appropriate anticoagulant effect when combined with platelet-directed therapy in patients with stable coronary artery disease is unknown. REG1 consists of RB006 (drug), an injectable RNA aptamer that specifically binds and inhibits factor IXa, and RB007 (antidote), the complementary oligonucleotide that neutralizes its anti-IXa activity. Methods and Results— We evaluated the safety, tolerability, and pharmacodynamic profile of REG1 in a randomized, double-blind, placebo-controlled study, assigning 50 subjects with coronary artery disease taking aspirin and/or clopidogrel to 4 dose levels of RB006 (15, 30, 50, and 75 mg) and RB007 (30, 60, 100, and 150 mg). The median age was 61 years (25th and 75th percentiles, 56 and 68 years), and 80% of patients were male. RB006 increased the activated partial thromboplastin time dose dependently; the median activated partial thromboplastin time at 10 minutes after a single intravenous bolus of 15, 30, 50, and 75 mg RB006 was 29.2 seconds (25th and 75th percentiles, 28.1 and 29.8 seconds), 34.6 seconds (25th and 75th percentiles, 30.9 and 40.0 seconds), 46.9 seconds (25th and 75th percentiles, 40.3 and 51.1 seconds), and 52.2 seconds (25th and 75th percentiles, 46.3 and 58.6) (P<0.0001; normal 25th and 75th percentiles, 27 and 40 seconds). RB007 reversed the activated partial thromboplastin time to baseline levels within a median of 1 minute (25th and 75th percentiles, 1 and 2 minutes) with no rebound increase through 7 days. No major bleeding or other serious adverse events occurred. Conclusions— This is the first experience of an RNA aptamer drug-antidote pair achieving inhibition and active restoration of factor IXa activity in combination with platelet-directed therapy in stable coronary artery disease. The preliminary clinical safety and predictable pharmacodynamic effects form the basis for ongoing studies in patients undergoing elective revascularization procedures.

Aortic counterpulsation: A review of the hemodynamic effects and indications for use

In the ever evolving field of cardiovascular medicine and coronary intervention, the intra‐aortic balloon pump (IABP) is a mature technology, which still plays an important role. The balloon pump invasively supports patient hemodynamics by augmenting diastolic perfusion and increasing diastolic blood pressure, thereby increasing coronary perfusion and reducing afterload. Its efficacy has been demonstrated in a multitude of clinical situations, including acute coronary syndromes, high‐risk coronary interventions, cardiogenic shock, and cardiovascular surgery. The potential complications of aortic counterpulsation are serious, although much lower than once feared. With proper patient selection, insertion technique, and management, the IABP is a powerful tool to assist in the treatment of patients with cardiovascular disease. This article will review the hemodynamics, indications, and complications associated with its use.© 2005 Wiley‐Liss, Inc.

Impact of Annual Operator and Institutional Volume on Percutaneous Coronary Intervention Outcomes A 5-Year United States Experience (2005–2009)

Background— The relationship between operator or institutional volume and outcomes among patients undergoing percutaneous coronary interventions (PCI) is unclear. Methods and Results— Cross-sectional study based on the Healthcare Cost and Utilization Project’s Nationwide Inpatient Sample between 2005 to 2009. Subjects were identified by International Classification of Diseases, 9th Revision, Clinical Modification procedure code, 36.06 and 36.07. Annual operator and institutional volumes were calculated using unique identification numbers and then divided into quartiles. Three-level hierarchical multivariate mixed models were created. The primary outcome was in-hospital mortality; secondary outcome was a composite of in-hospital mortality and peri-procedural complications. A total of 457 498 PCIs were identified representing a total of 2 243 209 PCIs performed in the United States during the study period. In-hospital, all-cause mortality was 1.08%, and the overall complication rate was 7.10%. The primary and secondary outcomes of procedures performed by operators in 4th [annual procedural volume; primary and secondary outcomes] [>100; 0.59% and 5.51%], 3rd [45–100; 0.87% and 6.40%], and 2nd quartile [16–44; 1.15% and 7.75%] were significantly less (P<0.001) when compared with those by operators in the 1st quartile [⩽15; 1.68% and 10.91%]. Spline analysis also showed significant operator and institutional volume outcome relationship. Similarly operators in the higher quartiles witnessed a significant reduction in length of hospital stay and cost of hospitalization (P<0.001). Conclusions— Overall in-hospital mortality after PCI was low. An increase in operator and institutional volume of PCI was found to be associated with a decrease in adverse outcomes, length of hospital stay, and cost of hospitalization.

First Clinical Application of an Actively Reversible Direct Factor IXa Inhibitor as an Anticoagulation Strategy in Patients Undergoing Percutaneous Coronary Intervention

Background— The ideal anticoagulant should prevent ischemic complications without increasing the risk of bleeding. Controlled anticoagulation is possible with the REG1 system, an RNA aptamer pair comprising the direct factor IXa inhibitor RB006 and its active control agent RB007. Methods and Results— This phase 2a study included a roll-in group (n=2) treated with REG1 plus glycoprotein IIb/IIIa inhibitors followed by 2 groups randomized 5:1 to REG1 or unfractionated heparin. In group 1 (n=12), RB006 was partially reversed with RB007 after percutaneous coronary intervention and fully reversed 4 hours later. In group 2 (n=12), RB006 was fully reversed with RB007 immediately after percutaneous coronary intervention. Femoral sheaths were removed after complete reversal. Patients were pretreated with aspirin and clopidogrel. End points included major bleeding within 48 hours; composite of death, myocardial infarction, or urgent target vessel revascularization within 14 days; and pharmacodynamic measures. All cases were successful, with final Thrombolysis in Myocardial Infarction grade 3 flow and no angiographic thrombotic complications. There were 2 ischemic end points in the REG1 group and 1 in the unfractionated heparin group, with 1 major bleed in the unfractionated heparin group. Median activated clotting time values rose from 151 to 236 seconds after RB006. Administration of the partial RB007 dose reversed anticoagulation to an intermediate activated clotting time value of 186 seconds. Complete reversal with RB007 returned the median activated clotting time value to 144 seconds. Both reversal strategies enabled scheduled femoral sheath removal. Conclusions— This study demonstrates the clinical translation of a novel platform of anticoagulation targeting factor IXa and its active reversal to percutaneous coronary intervention and provides the basis for further investigation. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00715455.