Outcomes in Multivessel Coronary Disease Stratified by The Society of Thoracic Surgeons Risk.

BACKGROUND: Surgical risk stratified outcomes after contemporary revascularization strategies have not been well described. We report these outcomes in patients undergoing percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) for multivessel coronary disease. METHODS: A total of 5836 patients with multivessel disease who underwent CABG (n = 4420) or PCI (n = 1416) were included in this retrospective observational analysis. Data were stratified based on The Society of Thoracic Surgeons risk score. A score less than 4% was considered low risk and a score greater than or equal to 4% was considered intermediate-high risk. Outcomes included mortality, inpatient readmissions, and repeat revascularizations. RESULTS: In the CABG population, 3863 (87.3%) were low risk and 557 (12.6%) were intermediate-high risk. The 5-year mortality for the low-risk cohort was 10.9% (95% confidence interval [CI], 9.83%-12.05%), and for the intermediate-high-risk cohort it was 40.1% (95% CI, 35.76%-44.54%). Among those undergoing PCI, 1163 (82.1%) were low risk, while 249 (17.6%) were intermediate-high risk. The 5-year mortality for the low-risk cohort was 21.6% (95% CI, 19.10%-24.26%), and for the intermediate-high-risk cohort it was 61.8% (95% CI, 54.72%-68.70%). CONCLUSIONS: This study reports outcomes stratified by surgical risk after PCI or CABG in patients with multivessel coronary disease. These data can help guide the revascularization strategy choice for individual patients.

Surgical versus percutaneous multivessel coronary revascularization in patients with chronic kidney disease.

OBJECTIVES: This study compared contemporary outcomes following surgical versus percutaneous coronary revascularization for multivessel coronary artery disease (MVCAD) in patients with chronic kidney disease. METHODS: Patients with MVCAD and a reduced glomerular filtration rate (<60 ml/min) undergoing coronary bypass surgery (CABG) or percutaneous coronary intervention (PCI) at a single institution between 2010 and 2017 were included. The primary outcome was major adverse cardiac and cerebrovascular events (MACCE) defined as a composite outcome of death, stroke, myocardial infarction or repeat revascularization. Multivariable Cox regression models were used for risk-adjustment and propensity matching was also performed. RESULTS: A total of 1853 patients were included in the study (1269 CABG, 584 PCI). CABG was associated with greater 5-year freedom from MACCE (70.1% vs 47.3%, P < 0.0001), a finding that persisted after risk-adjustment. The rates of early and late mortality and readmission were also lower with CABG as were individual rates of myocardial infarction and repeat revascularization. A propensity-matched analysis generated 704 well-matched patients (352 in each arm) with similar results, including greater 5-year freedom from MACCE (72.8% vs 45.8%, P < 0.0001), improved 5-year survival (73.9% vs 52.3%, P < 0.0001), lower readmission (cause-specific hazard ratio 0.68, 95% confidence interval 0.58-0.80; P < 0.0001), lower individual rates of myocardial infarction (2.6% vs 9.7%, P < 0.0001) and repeat revascularization (1.1% vs 7.4%, P < 0.0001). CONCLUSIONS: CABG is associated with a lower MACCE rate than that of PCI in patients with MVCAD and chronic kidney disease. Multidisciplinary discussions regarding the optimal revascularization strategy are important in MVCAD, particularly in more complex scenarios such as chronic kidney disease.

Coronary Bypass Versus Percutaneous Revascularization in Multivessel Coronary Artery Disease.

BACKGROUND: This study focused on contemporary outcomes after coronary artery bypass graft (CABG) surgery versus percutaneous coronary intervention (PCI) in patients with multivessel coronary artery disease (MVCAD). METHODS: This was a propensity-matched retrospective, observational analysis. Patients with MVCAD who underwent CABG or PCI between 2010 and 2018 and for whom data were available through the National Cardiovascular Data Registry or The Society of Thoracic Surgeons Adult Cardiac Surgery Database were included. The primary outcome was overall survival. Secondary outcomes included freedom from inpatient readmission and freedom from repeat revascularization. RESULTS: Of the initial 6,163 patients with MVCAD, the propensity-matched cohort included 844 in each group. The estimated 1-year mortality was 11.5% and 7.2% (p < 0.001) in the PCI and CABG groups, respectively, with an overall hazard ratio for mortality of PCI versus CABG of 1.64 (95% confidence interval [CI], 1.29 to 2.10; p < 0.001). The overall hazard ratio for readmission for PCI versus CABG was 1.42 (95% CI, 1.23 to 1.64; p < 0.001). The overall hazard ratio for repeat revascularization for PCI versus CABG was 4.06 (95% CI, 2.39 to 6.91; p < 0.001). Overall major adverse cardiovascular events and individual outcomes of mortality, readmission, and repeat revascularization all favored CABG across virtually all major clinical subgroups. CONCLUSIONS: This contemporary propensity-matched analysis of patients undergoing coronary revascularization for MVCAD demonstrates a significant mortality benefit with CABG over PCI, and this benefit is consistent across virtually all major patient subgroups. Futures studies are needed reflecting routine practice to assess how best to approach shared decision making and informed consent when it comes to revascularization decisions in any patient with MVCAD.

Longitudinal Outcomes of Women Undergoing Transcatheter Aortic Valve Replacement.

OBJECTIVE: Recent data have suggested that women have a survival benefit at 1-year follow-up. However, long-term gender-based TAVR outcomes are lacking. METHODS: All patients undergoing isolated TAVR from 2011 to 2017 were included. Patients were stratified by gender. The primary outcomes of the study were 3-year mortality and 3-year hospital readmissions. Multivariable logistic regression analysis was used to evaluate the risk-adjusted impact of gender on TAVR outcomes. RESULTS: A total of 1,036 patients were divided into male (n = 518) and female (n = 518) cohorts. Women had a borderline significantly increased STS PROM (8.3% ± 5 vs. 7.7% ± 4.4; P = 0.05). The majority of procedures were performed under conscious sedation (male: 89% vs. female: 88%; P = 0.62) and via transfemoral access (male: 81.8% vs. female: 81.4%; P = 0.46). There was no difference in operative (30-day) mortality (male: 15 [3.3%] vs. female: 17 [3.7%]; P = 0.77) or 30-day readmissions (male: 40 [10.8%] vs. female: 44 [12.2%]; P = 0.56). Perioperative blood product usage was higher for women (male: 8.1% vs. female: 14.1%; P = 0.002). There was no significant difference in major vascular complications (male: 0.4% vs. female: 1.0%; P = 0.26) or major bleeding (male: 0.2% vs. female: 0.4%; P = 0.56). Permanent pacemaker placement was higher for males (11.6% vs. 7.0%; P = 0.01). On risk-adjusted multivariable analysis, gender was not a factor associated with mortality (HR 0.99 [0.76 to 1.30]; P = 0.99) or readmission (HR 0.90 [0.72 to 1.14]; P = 0.42) at 5 years. CONCLUSIONS: There was no difference in survival or readmissions on multivariable analysis for women undergoing TAVR at 3 years. Longitudinal multi-institutional data will be important to validate these findings.

Long-term Hospital Readmissions After Surgical Vs Transcatheter Aortic Valve Replacement.

BACKGROUND: Limited data exist for rates and causes of readmission beyond short-term follow-up for patients undergoing surgical and transcatheter aortic valve replacement (SAVR and TAVR) METHODS: Patients undergoing isolated SAVR and TAVR between 2011 and 2017 at our institution were included in this study. The primary outcome was 5-year hospital readmission. The readmission cohort was identified from index readmission. Multivariable logistic regression analysis was used to evaluate the risk-adjusted impact of TAVR vs SAVR on outcomes. RESULTS: A total of 2379 patients were included: 1034 TAVR (43.5%) and 1345 SAVR (56.5%). Patients undergoing TAVR were on average older (81.8 ± 7.8 years vs 69.1 ± 11.85 years, P < .0001) and had more comorbidities than SAVR patients as represented by a greater Society of Thoracic Surgeons Predicted Risk of Mortality (7.96% ± 4.71% vs 2.73% ± 2.93%, P < .0001). Operative mortality was higher in the TAVR cohort (3.19% vs 1.12%, P < .004) and remained high at 5 years despite risk adjustment. Significantly more cardiac readmissions were found at 5-year follow-up in the TAVR group (73.3% vs 60.0%, P < .0001). Heart failure was the most common cause of cardiac readmission in the TAVR cohort (58.7% vs 42.1%, P = .0001). No difference was found in overall readmission risk at 30 days (hazard ratio [HR] 1.23, 95% confidence interval [CI]: 0.94 to 1.61, P = .12), 1 year (HR 0.93, 95% CI: 0.77 to 1.16, P = .52), and 5 years (HR 0.99, 95% CI: 0.83 to 1.18, P = .89). CONCLUSIONS: There is a disproportionately high rate of long-term hospital readmissions for cardiac causes, including heart failure, in patients who underwent TAVR. These data may support aggressive medical management of patients with careful follow-up in patients undergoing TAVR.

Open Surgical Access for Transfemoral TAVR Should Not Be a Contraindication for Conscious Sedation.

OBJECTIVES: The use of monitored anesthesia care (MAC) for transcatheter aortic valve replacement (TAVR) is gaining favor in the United States, although general anesthesia (GA) continues to be common for these procedures. Open surgical cutdown for transfemoral TAVR has been a relative contraindication for TAVR with MAC at most centers. The objective of this study was to review the authors' results of transfemoral TAVR performed in patients with open surgical cutdown with the use of MAC. DESIGN: Retrospective study design from a prospectively recorded database. SETTING: Tertiary academic (teaching) hospital. PARTICIPANTS: Two hundred eighty-two patients undergoing transfemoral TAVR with open surgical cutdown under MAC from 2015 to 2017. INTERVENTIONS: Transfemoral TAVR under MAC with surgical cutdown for femoral vascular access. MEASUREMENTS AND MAIN RESULTS: The study cohort consisted of 282 patients with severe aortic stenosis (mean area 0.65 [± 0.16] cm2, mean gradient of 48.9 [±13.3] mmHg, and mean age of 82.7 [± 7.31] years). Eleven (3.9%) patients required conversion to GA. First postoperative pain score (0-10) was 2.9 and highest postoperative pain score was 4.6. Major and minor vascular complications occurred in 2 (0.7%) and 6 (2.1%) patients, respectively. Twenty-nine (10.3%) patients were readmitted within 30 days, and 6 (2.1%) patients had in-hospital mortality. CONCLUSIONS: Open surgical cutdown for transfemoral TAVR can be performed safely using MAC and ilioinguinal block with low rates of conversion to general anesthesia and acceptable postoperative outcomes and pain scores.

Impact of cigarette taxes on smoking prevalence from 2001-2015: A report using the Behavioral and Risk Factor Surveillance Survey (BRFSS).

OBJECTIVES: To provide an up-to-date analysis on the relationship between excise taxes and the prevalence of cigarette smoking in the United States. METHODS: Linear mixed-effects models were used to model the relationship between excise taxes and prevalence of cigarette smoking in each state from 2001 through 2015. RESULTS: From 2001 through 2015, increases in state-level excise taxes were associated with declines in prevalence of cigarette smoking. The effect was strongest in young adults (age 18-24) and weakest in low-income individuals (<$25,000). CONCLUSIONS: Despite the shrinking pool of current smokers, excise taxes remain a valuable tool in public-health efforts to reduce the prevalence of cigarette smoking. POLICY IMPLICATIONS: States with high smoking prevalence may find increased excise taxes an effective measure to reduce population smoking prevalence. Since the effect is greatest in young adults, benefits of increased tax would likely accumulate over time by preventing new smokers in the pivotal young-adult years.

Surgical cut down for vascular access with conscious sedation for transcatheter aortic valve replacement: the best of both worlds?

OBJECTIVES: Despite the established efficacy of transcatheter aortic valve replacement for aortic valve replacement, vascular complications remain a major cause of procedural morbidity and mortality. In this study, we evaluate the use of femoral artery cut down with conscious sedation and report outcomes and complications associated with this approach. METHODS: Our study included 282 patients undergoing transcatheter aortic valve replacement with conscious sedation and surgical cut down for femoral access between 2015 and 2017. Data were prospectively recorded in the local institutional database and were retrospectively accessed. Descriptive statistics are presented, and a Kaplan-Meier time-to-event plot was used to estimate 1-year survival. RESULTS: The mean age of the patients was 82.7 ± 7.31 years and consisted of 146 (52%) women. Echocardiographic data demonstrated a severe aortic stenosis with a mean area of 0.65 ± 0.16 cm2 and a mean gradient of 48.9 ± 13.3 mmHg. STS-PROM for the cohort was 7.2%, representing an intermediate risk group. Six (2.2%) patients died within 30 days after transcatheter aortic valve replacement. Major vascular complications occurred in 2 (0.7%) patients and minor vascular complications occurred in 6 (2.2%) patients in our cohort. Wound complications were observed in 2 (0.7%) patients. CONCLUSIONS: We demonstrate that the use of conscious sedation and surgical cut down for femoral arterial access resulted in a major vascular complication rate of less than 1% and low in-hospital mortality rates without any significant increase in wound complications.

Outcomes of Heart Failure Admissions Under Observation Versus Short Inpatient Stay.

BACKGROUND: Patients with heart failure (HF) are admitted either under observation (OBS) or inpatient stays; however, there is little data on whether this designation reflects the clinical status of a patient, with significant logistical and financial implications. We sought to compare the outcomes of patients with HF admitted OBS versus inpatient stay (≤2 days; INPT). METHODS AND RESULTS: From January 1, 2008 to September 30, 2015, our multisite health system saw 21 339 unique patients totaling 52 493 hospital admissions with a primary diagnosis of HF. Patients were excluded if they underwent cardiac surgery (n=611), heart transplantation (n=187), or left ventricular assist device insertion (n=198), or if they died during hospitalization (n=1839). Of the remaining 50 654 discharges, 2 groups were identified: INPT group and OBS group. Outcomes were HF readmission, all-cause readmission, and all-cause mortality within 1 year of discharge. Hazard ratios were computed using the Andersen-Gill method in the Cox proportional-hazards model. A total of 8709 admissions (17%) occurred in the INPT group and 2648 admissions (5%) occurred in the OBS group. HF readmission rate at 1 year was 55.3% in INPT versus 66.5% in OBS (hazard ratio, 0.75; 95% confidence interval, 0.71-0.80; P<0.01). All-cause readmission rate at 1 year was 70.7% in INPT versus 82.5% in OBS (hazard ratio, 0.74; 95% confidence interval, 0.70-0.78; P<0.01). All-cause mortality at 1 year occurred in 25.2% of INPT versus 24.2% of OBS (hazard ratio, 1.03; 95% confidence interval, 0.95-1.12; P=0.46). CONCLUSIONS: HF admissions designated INPTs were associated with lower readmission rates and equivalent mortality to those designated OBS.

Cardiac amyloidosis is prevalent in older patients with aortic stenosis and carries worse prognosis.

BACKGROUND: Non-invasive cardiac imaging allows detection of cardiac amyloidosis (CA) in patients with aortic stenosis (AS). Our objective was to estimate the prevalence of clinically suspected CA in patients with moderate and severe AS referred for cardiovascular magnetic resonance (CMR) in age and gender categories, and assess associations between AS-CA and all-cause mortality. METHODS: We retrospectively identified consecutive AS patients defined by echocardiography referred for further CMR assessment of valvular, myocardial, and aortic disease. CMR identified CA based on typical late-gadolinium enhancement (LGE) patterns, and ancillary clinical evaluation identified suspected CA. Survival analysis with the Log rank test and Cox regression compared associations between CA and mortality. RESULTS: There were 113 patients (median age 74 years, Q1-Q3: 62-82 years), 96 (85%) with severe AS. Suspected CA was present in 9 patients (8%) all > 80 years. Among those over the median age of 74 years, the prevalence of CA was 9/57 (16%), and excluding women, the prevalence was 8/25 (32%). Low-flow, low-gradient physiology was very common in CA (7/9 patients or 78%). Over a median follow-up of 18 months, 40 deaths (35%) occurred. Mortality in AS + CA patients was higher than AS alone (56% vs. 20% at 1-year, log rank 15.0, P < 0.0001). Adjusting for aortic valve replacement modeled as a time-dependent covariate, Society of Thoracic Surgery predicted risk of mortality, left ventricular ejection fraction, CA remained associated with all-cause mortality (HR = 2.92, 95% CI = 1.09-7.86, P = 0.03). CONCLUSIONS: Suspected CA appears prevalent among older male patients with AS, especially with low flow, low gradient AS, and associates with all-cause mortality. The importance of screening for CA in older AS patients and optimal treatment strategies in those with CA warrant further investigation, especially in the era of transcatheter aortic valve implantation.

Surgical or Transcatheter Aortic-Valve Replacement in Intermediate-Risk Patients.

BACKGROUND: Although transcatheter aortic-valve replacement (TAVR) is an accepted alternative to surgery in patients with severe aortic stenosis who are at high surgical risk, less is known about comparative outcomes among patients with aortic stenosis who are at intermediate surgical risk. METHODS: We evaluated the clinical outcomes in intermediate-risk patients with severe, symptomatic aortic stenosis in a randomized trial comparing TAVR (performed with the use of a self-expanding prosthesis) with surgical aortic-valve replacement. The primary end point was a composite of death from any cause or disabling stroke at 24 months in patients undergoing attempted aortic-valve replacement. We used Bayesian analytical methods (with a margin of 0.07) to evaluate the noninferiority of TAVR as compared with surgical valve replacement. RESULTS: A total of 1746 patients underwent randomization at 87 centers. Of these patients, 1660 underwent an attempted TAVR or surgical procedure. The mean (±SD) age of the patients was 79.8±6.2 years, and all were at intermediate risk for surgery (Society of Thoracic Surgeons Predicted Risk of Mortality, 4.5±1.6%). At 24 months, the estimated incidence of the primary end point was 12.6% in the TAVR group and 14.0% in the surgery group (95% credible interval [Bayesian analysis] for difference, -5.2 to 2.3%; posterior probability of noninferiority, >0.999). Surgery was associated with higher rates of acute kidney injury, atrial fibrillation, and transfusion requirements, whereas TAVR had higher rates of residual aortic regurgitation and need for pacemaker implantation. TAVR resulted in lower mean gradients and larger aortic-valve areas than surgery. Structural valve deterioration at 24 months did not occur in either group. CONCLUSIONS: TAVR was a noninferior alternative to surgery in patients with severe aortic stenosis at intermediate surgical risk, with a different pattern of adverse events associated with each procedure. (Funded by Medtronic; SURTAVI ClinicalTrials.gov number, NCT01586910 .).

Assessment of P2Y12 inhibitor usage and switching in acute coronary syndrome patients undergoing percutaneous coronary revascularization.

BACKGROUND: Dual antiplatelet therapy is recommended for patients with acute coronary syndrome (ACS) that undergo percutaneous coronary intervention (PCI). However, the effect of switching P2Y12 inhibitors between the loading dose and therapy after discharge is not well described. METHODS: This post-hoc analysis of a prospectively collected registry included 3219 consecutive ACS patients who underwent PCI. Patients were categorized into four groups: clopidogrel at load and discharge (C-C), loading dose of clopidogrel and discharged on prasugrel/ticagrelor (C-PT), loading dose of prasugrel/ticagrelor and discharged on clopidogrel (PT-C), and prasugrel/ticagrelor at load and discharge (PT-PT). RESULTS: While 77.6% of patients received the C-C treatment regimen and 13.6% received the PT-PT strategy, the strategy of P2Y12 switching was fairly common with 6.2% in the PT-C group and 2.6% in the C-PT group. While C-C was the most common treatment regimen, PT-C and PT-PT were more commonly used in STEMI patients than in NSTEMI or unstable angina patients. A significantly lower unadjusted incidence of the composite outcome (death, MI, and repeat revascularization) was appreciated in both the PT-C (1.0%) and PT-PT (2.3%) groups than the C-C group (4.0%). Propensity-score matched analysis still showed significantly reduced risk (HR=0.22, 95% CI 0.05-0.93, p=0.04) in the PT-C group vs. a matched group of C-C controls. CONCLUSIONS: The strategy of utilizing a newer P2Y12 inhibitor and then switching to clopidogrel in ACS patients following PCI is used with some frequency in routine clinical practice and further studies should evaluate the safety and efficacy of such a strategy.

Safety and efficacy of implementing a multidisciplinary heart team approach for revascularization in patients with complex coronary artery disease: an observational cohort pilot study.

IMPORTANCE: Since the advent of transcatheter aortic valve replacement, the multidisciplinary heart team (MHT) approach has rapidly become the standard of care for patients undergoing the procedure. However, little is known about the potential effect of MHT on patients with coronary artery disease (CAD). OBJECTIVE: To determine the safety and efficacy of implementing the MHT approach for patients with complex CAD. DESIGN, SETTING, AND PARTICIPANTS: Observational cohort pilot study of 180 patients with CAD involving more than 1 vessel in a single major academic tertiary/quaternary medical center. From May 1, 2012, through May 31, 2013, MHT meetings were convened to discuss evidence-based management of CAD. All cases were reviewed by a team of interventional cardiologists and cardiac surgeons within 72 hours of angiography. All clinical data were reviewed by the team to adjudicate optimal treatment strategies. Final recommendations were based on a consensus decision. Outcome measures were tracked for all patients to determine the safety and efficacy profile of this pilot program. EXPOSURES: Multidisciplinary heart team meeting. MAIN OUTCOMES AND MEASURES: Thirty-day periprocedural mortality and rate of major adverse cardiac events. RESULTS: Most of the patients underwent percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG); a small percentage of patients underwent a hybrid procedure or medical management. Incidence of 30-day periprocedural mortality was low across all groups of patients (PCI group, 5 of 64 [8%]; CABG group, 1 of 87 [1%]). The rate of major adverse cardiac events during a median follow-up of 12.1 months ranged from 12 of 87 patients (14%) in the CABG group to 15 of 64 (23%) in the PCI group. CONCLUSIONS AND RELEVANCE: Outcomes of patients with complex CAD undergoing the optimal treatment strategy recommended by the MHT were similar to those of published national standards. Implementation of the MHT approach for patients with complex CAD is safe and efficacious.

Benefit of long-term dual anti-platelet therapy in patients treated with drug-eluting stents: from the NHLBI dynamic registry.

The optimal duration of dual-antiplatelet therapy (DAPT) after drug-eluting stent (DES) implantation is an important, unanswered question. This study was designed to evaluate the association of varying durations of DAPT on clinical outcomes after DES implantation for the treatment of coronary artery disease. Using the National Heart, Lung, and Blood Institute Dynamic Registry, patients enrolled in the last 2 waves after index percutaneous coronary intervention with DES and who were event free at the time of landmark analysis were included. Landmark analysis was performed 12 and 24 months after percutaneous coronary intervention, and patients were stratified according to continued use of DAPT or not. Subjects were evaluated for rates of death, myocardial infarction, and stent thrombosis at 4 years from their index procedures. The numbers of evaluable patients were 2,157 and 1,918 for the 12- and 24-month landmarks, respectively. In both landmark analyses, there was a significantly lower 4-year rate of death or myocardial infarction in the group that continued DAPT compared to the group that did not (12 months: 10.5% vs 14.5%, p = 0.01; 24 months: 5.7% vs 8.6%, p = 0.02). Beneficial differences in the group that continued on DAPT were preserved after multivariate and propensity adjustment. There were no significant differences in definite stent thrombosis in either landmark analysis. In conclusion, at 12 and 24 months after DES implantation, continued use of DAPT was associated with lower 4-year risk for death and myocardial infarction.

Impact of anemia on platelet response to clopidogrel in patients undergoing percutaneous coronary stenting.

High residual platelet reactivity (HRPR) on clopidogrel is a predictor of recurrent ischemic events in patients undergoing percutaneous coronary interventions (PCI). Significant intraindividual variability in platelet aggregation on repeat testing has been reported. To understand factors contributing to the variability in platelet aggregation testing, we examined clinical and laboratory elements linked to HRPR in 255 consecutive patients tested ≥12 hours after PCI using light transmission aggregometry (LTA) in response to adenosine diphosphate 5 µmol/L and VerifyNow P2Y12 assay (VNP2Y12; Accumetrics). HRPR was defined as >46% residual aggregation for LTA and >236 P2Y12 response units (PRUs) for VNP2Y12. On multivariate analysis the only variable independently associated with HRPR with both LTA and VNP2Y12 was laboratory-defined anemia. Prevalences of HRPR by LTA were 34.3% in anemic patients, 15.6% in patients with normal hemoglobin levels, and 59.8% versus 25.9% by VNP2Y12 (p <0.005 for the 2 comparisons). In a subgroup of 50 patients, testing was done before and after the clopidogrel loading dose. At baseline there were no differences in platelet aggregation with either assay; however, absolute decrease in reactivity after the clopidogrel load was significantly less in anemic patients compared to patients with normal hemoglobin (change in residual aggregation by LTA 15.8 ± 5.8% vs 28.8 ± 3.2%, p <0.05; change in PRU by VNP2Y12 56.5 ± 35.5 vs 145.0 ± 14.2 PRUs, p <0.05, respectively). In conclusion, anemia is an important contributor to apparent HRPR on clopidogrel and may explain some of the intraindividual variability of platelet aggregation testing.

Clinical utility of regadenoson for assessing fractional flow reserve.

OBJECTIVES: The aim of this study was to evaluate the efficacy of regadenoson, in comparison with adenosine, for assessing fractional flow reserve (FFR) of intermediate coronary artery stenoses (CAS). BACKGROUND: Fractional flow reserve is an established invasive method for assessing the physiological significance of CAS. Regadenoson, a selective A(2A) receptor agonist, is an approved hyperemic agent for pharmacological stress imaging, but its role for measuring FFR is unknown. METHODS: This prospective, single-center study enrolled 25 consecutive patients with intermediate CAS discovered during elective angiography (25 lesions). In each patient, FFR of the CAS was measured first by IV adenosine (140 µg/kg/min), followed by IV regadenoson (400 µg bolus). The intrapatient FFR correlation between adenosine and regadenoson was evaluated. RESULTS: The mean age was 63 ± 11 years, and mean left ventricular ejection fraction was 58 ± 11%. Most patients were male (52%) and had hypertension (84%) and dyslipidemia (84%), with 24% having diabetes mellitus and 20% chronic obstructive pulmonary disease. The CAS was visually estimated during angiography (mean 58 ± 9%) and most often found in the left anterior descending coronary artery (48%). A strong, linear correlation of FFR was noted with adenosine and regadenoson (r = 0.985, p < 0.001). A hemodynamically significant lesion (FFR ≤ 0.80) was present in 52% with no reclassification of significance between adenosine and regadenoson. No serious events occurred with administration of either drug. CONCLUSIONS: Our results suggest that a single IV bolus of regadenoson is as effective as an intravenous infusion of adenosine for measuring FFR and, given its ease of use, should be considered for FFR measurement in the catheterization laboratory.

Calcium-dependent arrhythmias in transgenic mice with heart failure.

Transgenic mice overexpressing the inflammatory cytokine tumor necrosis factor (TNF)-alpha (TNF-alpha mice) in the heart develop a progressive heart failure syndrome characterized by biventricular dilatation, decreased ejection fraction, atrial and ventricular arrhythmias on ambulatory telemetry monitoring, and decreased survival compared with nontransgenic littermates. Programmed stimulation in vitro with single extra beats elicits reentrant ventricular arrhythmias in TNF-alpha (n = 12 of 13 hearts) but not in control hearts. We performed optical mapping of voltage and Ca(2+) in isolated perfused ventricles of TNF-alpha mice to study the mechanisms that lead to the initiation and maintenance of the arrhythmias. When compared with controls, hearts from TNF-alpha mice have prolonged of action potential durations (action potential duration at 90% repolarization: 23 +/- 2 ms, n = 7, vs. 18 +/- 1 ms, n = 5; P < 0.05), no increased dispersion of refractoriness between apex and base, elevated diastolic and depressed systolic [Ca(2+)], and prolonged Ca(2+) transients (72 +/- 6 ms, n = 10, vs. 54 +/- 5 ms, n = 8; P < 0.01). Premature beats have diminished action potential amplitudes and conduct in a slow, heterogeneous manner. Lowering extracellular [Ca(2+)] normalizes conduction and prevents inducible arrhythmias. Thus both action potential prolongation and abnormal Ca(2+) handling may contribute to the initiation of reentrant arrhythmias in this heart failure model by mechanisms distinct from enhanced dispersion of refractoriness or triggered activity.

Gli2, but not Gli1, is required for initial Shh signaling and ectopic activation of the Shh pathway.

The Shh signaling pathway is required in many mammalian tissues for embryonic patterning, cell proliferation and differentiation. In addition, inappropriate activation of the pathway has been implicated in many human tumors. Based on transfection assays and gain-of-function studies in frog and mouse, the transcription factor Gli1 has been proposed to be a major mediator of Shh signaling. To address whether this is the case in mouse, we generated a Gli1 null allele expressing lacZ. Strikingly, Gli1 is not required for mouse development or viability. Of relevance, we show that all transcription of Gli1 in the nervous system and limbs is dependent on Shh and, consequently, Gli1 protein is normally not present to transduce initial Shh signaling. To determine whether Gli1 contributes to the defects seen when the Shh pathway is inappropriately activated and Gli1 transcription is induced, Gli1;Ptc double mutants were generated. We show that Gli1 is not required for the ectopic activation of the Shh signaling pathway or to the early embryonic lethal phenotype in Ptc null mutants. Of significance, we found instead that Gli2 is required for mediating some of the inappropriate Shh signaling in Ptc mutants. Our studies demonstrate that, in mammals, Gli1 is not required for Shh signaling and that Gli2 mediates inappropriate activation of the pathway due to loss of the negative regulator Ptc.

Pbx1 inactivation disrupts pancreas development and in Ipf1-deficient mice promotes diabetes mellitus.

Pbx1 is a member of the TALE (three-amino acid loop extension) class of homeodomain transcription factors, which are components of hetero-oligomeric protein complexes thought to regulate developmental gene expression and to maintain differentiated cell states. In vitro studies have shown that Pbx1 regulates the activity of Ipf1 (also known as Pdx1), a ParaHox homeodomain transcription factor required for the development and function of the pancreas in mice and humans. To investigate in vivo roles of Pbx1 in pancreatic development and function, we examined pancreatic Pbx1 expression, and morphogenesis, cell differentiation and function in mice deficient for Pbx1. Pbx1-/- embryos had pancreatic hypoplasia and marked defects in exocrine and endocrine cell differentiation prior to death at embryonic day (E) 15 or E16. In these embryos, expression of Isl1 and Atoh5, essential regulators of pancreatic morphogenesis and differentiation, was severely reduced. Pbx1+/- adults had pancreatic islet malformations, impaired glucose tolerance and hypoinsulinemia. Thus, Pbx1 is essential for normal pancreatic development and function. Analysis of trans-heterozygous Pbx1+/- Ipf1+/- mice revealed in vivo genetic interactions between Pbx1 and Ipf1 that are essential for postnatal pancreatic function; these mice developed age-dependent overt diabetes mellitus, unlike Pbx1+/- or Ipf1+/- mice. Mutations affecting the Ipf1 protein may promote diabetes mellitus in mice and humans. This study suggests that perturbation of Pbx1 activity may also promote susceptibility to diabetes mellitus.

Myocardial contrast echocardiography can be used to assess the microvascular response to vascular endothelial growth factor-121.

BACKGROUND: Therapeutic angiogenesis is a new approach to treating ischemic heart disease, and the optimal method for assessing its efficacy is unclear. We used myocardial contrast echocardiography (MCE) to evaluate the therapeutic response to the angiogenic agent, vascular endothelial growth factor-121 (VEGF121). METHODS AND RESULTS: After placement of an ameroid constrictor (day 0) around the left anterior descending artery (LAD), dogs were given intracoronary VEGF121 protein (108 microg, n=6) or placebo (n=6) on days 7 and 21, and subcutaneous VEGF121 (1 mg) or placebo on days 8 to 20 and 22 to 27. On day 48, MCE was performed during rest and dobutamine stress. Videointensity (y) and pulsing interval (t) were fit to an exponential model (y=A[1-e(-beta(t))]) used to derive indices of red cell velocity (beta) and capillary area (A), and parameters were compared with radiolabeled microsphere flow data. VEGF(121) treatment resulted in higher resting left anterior descending artery/left circumflex flow ratio compared with placebo (P<0.03) and improved collateral flow reserve. Beta was 0.94+/-0.37 in VEGF121 dogs versus 0.38+/-0.31 in controls (P<0.02), with the greatest difference in the endocardium. The parameter A was comparable in both groups, suggesting that microvascular changes did not alter capillary cross-sectional area, and histology indicated a trend toward higher arteriolar density in VEGF121-treated animals. CONCLUSIONS: VEGF121 protein improves collateral flow and reserve. MCE can evaluate the transmural location and structural and functional responses of the microvasculature to angiogenic interventions.