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Increased radiation exposure with transradial access for coronary procedures

8 Dec, 15 | by flee

Compared with the transfemoral approach, coronary angiography and percutaneous coronary intervention (PCI) performed via transradial access reduces rates of bleeding and vascular complications.  However, the potential for increased radiation exposure to patients and operators may be a barrier to the adoption of the transradial approach.  In this systematic review and meta-analysis of 24 published studies comparing transradial and transfemoral access for coronary angiography and PCI, the authors compared the differences in radiation exposure between access approaches as measured by fluoroscopy time (min) and kerma-area product (KAP, Gy cm2).  After a rigorous search to identify studies of coronary procedural access that reported radiation exposure, the authors found 24 published randomized controlled trials from 1996-2014 with 19,328 patients for analysis.  Comparing radiation exposure by access site strategy, the authors found a statistically significant increase in fluoroscopy time for diagnostic coronary angiography (DCA) (weighted mean difference [WMD]: 1.04 min [95% CI 0.84-1.24]) and PCI (WMD fluoroscopy time 1.15 min [95% CI 0.96–1.33]), while only a statistically significant increase in KAP for PCI (0.55 Gy cm2 [95% CI 0.08–1.02] but not DCA (1.72 Gy cm2 [95% CI −0.10 – 3.55]. In meta-regression analysis comparing differences in radiation exposure by year of study, differences in fluoroscopy time between transradial and transfemoral approaches decreased over time.  The analysis was limited by significant heterogeneity in the pooled studies (I2 > 75%).

 

Conclusion: This systematic review and meta-analysis suggests transradial access for coronary procedures is associated with a small increase in radiation exposure.  However, this gap in radiation exposure between transradial and transfemoral access has closed over time, presumably reflecting increased operator experience with transradial access.  Further, the clinical significance of the observed difference in radiation exposure is unclear. Given the benefits of transradial access for reducing rates of periprocedural complications, these findings should not discourage use of transradial access.  Instead, these findings emphasize the importance of continued attention to radiation safety as operators adopt a transradial approach.

 

Summarized by Javier A. Valle and Steven M. Bradley

 

Plourde G, Pancholy SB, Nolan J, Jolly S, Rao SV, et al. Radiation exposure in relation to the arterial access site used for diagnostic coronary angiography and percutaneous coronary intervention: a systematic review and meta-analysis

Lancet 2015; 386: 2192–203

Long-term data on fractional flow reserve guided PCI

8 Dec, 15 | by flee

The Fractional Flow Reserve versus Angiography for Multivessel Evaluation (FAME) trial was a landmark study of the use of fractional flow reserve (FFR) to guide coronary revascularization through the identification of ischemia-inducing stenosis at the time of coronary angiography. The previously published 1- and 2-year results of the FAME trial demonstrated fewer major adverse cardiac events in the FFR arm as compared to patients undergoing revascularization guided by angiographic assessment alone.  In the current study, the authors present the 5-year follow-up data from the FAME trial.  The original trial enrolled 1005 patients across 20 centers from 2006 to 2007, with 496 randomized to angiography-guided revascularization and 506 to FFR-guided revascularization.  Of these patients, 429 in the angiography-guided arm and 436 in the FFR-guided arm were included in the 5-year follow-up (86% overall).  At 5 years, there was no difference between treatment arms for major adverse cardiac events (31% angiography vs. 28% FFR, relative risk 0.91 [95% CI 0.75-1.10]), or individual outcomes of all cause mortality, myocardial infarction, or coronary revascularization. Similarly, cardiac mortality was not significantly different between treatment arms (16% angiography vs. 13% FFR, p= 0.21).  A sensitivity analysis in which death was assumed for lost-to-follow-up patients demonstrated similar findings.

 

Conclusions: At 5-years follow up, FFR-guided revascularization demonstrated similar outcomes when compared with revascularization guided by angiography alone.  These findings provide reassurance that the early benefits of FFR targeted revascularization are not overwhelmed by late events.

 

Summarized by Javier A. Valle and Steven M. Bradley

 

van Nunen LX, Zimmermann FM, Tonino PAL, Barbato E, Baumbach A, Engstrøm T, et al. Fractional flow reserve versus angiography for guidance of PCI in patients with multivessel coronary artery disease (FAME): 5-year follow-up of a randomised controlled trial. Lancet 2015; 386: 1853–60.

Sub-clinical valve thrombosis in the setting of bioprosthetic aortic valves

25 Nov, 15 | by flee

Bioprosthetic aortic valves have played a critical role in improving both quality of life and prognosis in patients with severe aortic valve disease. Implanted either surgically (SAVR) or percutaneously (TAVI), they provide restoration of valve function without the need for anticoagulation as required with mechanical valves.  This study was the result of clinical evaluation of a patient with a stroke soon after TAVI.  This evaluation included CT imaging of the bioprosthetic valve which revealed restricted leaflet mobility and prompted further inquiry.  Using data from a TAVI randomized trial and 2 registries of patients with both TAVI and SAVR, the authors went on to evaluate 187 patients who underwent CT and echocardiographic imaging during the first 12 months after bioprosthetic valve implantation in the aortic position.  The authors found reduced leaflet motion was not uncommon with 40% of patients in the clinical trial and 13% in the two registries having findings of moderate to severe restriction in 1 or more valve leaflets.  Although the cause of restricted motion could not be determined definitively, imaging suggested thrombus at the base of the valve leaflets that impaired normal leaflet excursion.  The possibility that thrombus was the causal factors was further suggested by the lack of impaired leaflet motion in any patient who was anticoagulated with warfarin.  In addition, among patients with restricted leaflet motion, restoration of leaflet motion was found in 100% of patients who were subsequently started on warfarin as compared with 10% of patients not anticoagulated (P<0.001).  Interestingly, abnormalities in leaflet motion could not be seen on standard transthoracic echo imaging and there was no evidence of an increased gradient across valves with restricted leaflet motion by CT or TEE.  The clinical consequences of this finding remain unclear with no increase in stroke or TIA patients with restricted leaflet motion, although the sample size was small.

Conclusion

Using advanced imaging techniques, reduced motion of bioprosthetic aortic valves was commonly observed and suggestive of subclinical valve thrombosis.  The clinical consequences of this finding remain uncertain and further study is warranted to ascertain optimal imaging approaches and management of this finding.

Summarized by Hussain Contractor and Steven M. Bradley

Makkar RR, Fontana G, Jilaihawi H, Chakravarty T, Kofoed KF, de Backer O, Asch FM, Ruiz CE, Olsen NT, Trento A, Friedman J, Berman D, Cheng W, Kashif M, Jelnin V, Kliger CA, Guo H, Pichard AD, Weissman NJ, Kapadia S, Manasse E, Bhatt DL, Leon MB, Søndergaard L. Possible Subclinical Leaflet Thrombosis in Bioprosthetic Aortic Valves. N Engl J Med. 2015 Oct 5. [Epub ahead of print]

Absorbable stents non-inferior….but is that enough?

25 Nov, 15 | by flee

A coronary artery stent that scaffolds the vessel immediately after angioplasty but disappears over time has been proposed as means to avoid complications of late stent thrombosis and restore physiological vasomotion.  Bioabsorbable platforms (termed scaffolds) are designed to slowly dissolve over 2 to 3 years, leaving little or no residue in the vessel.  However, conventional stent technology sets a very high bar with low rates of late complications, many years of operator experience, and large numbers of prior trials.  In the ABSORB III trial a total of 2008 patients with stable or unstable angina were randomized in a 2:1 fashion to revascularization with either the ABSORB bioabsorbable scaffold or a conventional drug-eluting stent (in this case the everolimus-eluting XIENCE platform).  The study was designed as a non-inferiority trial with a primary end-point of cardiac death, target-vessel myocardial infarction, or ischemia-driven target-lesion revascularization.  At 1 year of follow-up, the study demonstrated no significant difference in the primary end-point (7.8% vs. 6.1%, P=0.007 for noninferiority and P=0.16 for superiority) and no significant difference between the two groups in the individual components of the end-point.  However, it the point-estimates for adverse events were higher among patients receiving the bioabsorbable scaffold.

Conclusions

In this large study comparing first generation bioabsorbable coronary scaffolds against conventional third generation metallic drug-eluting stents, the bioabsorbable scaffolds demonstrated non-inferiority within the pre-specified margin of 4.5% in terms of both efficacy and safety.  However, the point estimates for bioabsorbable scaffolds in this trial raise concern about the true benefits, and even potential for harm, of this new technology.  Longer term data in larger studies is needed prior to wholesale adoption of absorbable coronary scaffolds in clinical practice.

Summarized by Hussain Contractor and Steven M. Bradley

Ellis SG, Kereiakes DJ, Metzger DC, Caputo RP, Rizik DG, Teirstein PS, Litt MR, Kini A, Kabour A, Marx SO, Popma JJ, McGreevy R, Zhang Z, Simonton C, Stone GW; ABSORB III Investigators. Everolimus-Eluting Bioresorbable Scaffolds for Coronary Artery Disease. N Engl J Med. 2015 Oct 12. [Epub ahead of print]

Similar Outcomes with Bivalirudin and Unfractionated Heparin During PCI for Acute Coronary Syndromes

4 Nov, 15 | by flee

Approximately two-thirds of all PCI are performed for acute coronary syndromes.  In this setting, the optimal balance of anticoagulation to avoid thrombosis against the risk of major bleeding is a pivotal area of procedural management.  Multiple clinical trials have compared bivalirudin and heparin (+/- IIb/IIIa inhibitor), but the optimal strategy remains debated.  In particular, changes in clinical practice, namely increasing use of radial access and decreasing use of IIb/IIIa inhibitors, may influence the optimal antithrombotic treatment strategy.  In the MATRIX trial, 7213 patients with an acute coronary syndrome (55% with ST-elevation) were randomly allocated to receive either bivalirudin or heparin at 70-100u/kg peri-procedurally with an additional randomization step at procedural completion to either stop bivalirudin or continue the infusion for 4 to 6 hours.  Approximately 25% of the heparin group also received a IIb/IIIa inhibitor at the treating physician’s discretion.  There was no significant difference in rates of major adverse cardiovascular events between the bivalirudin and heparin groups (10.3% vs. 10.9%; RR, 0.94; 95% CI, 0.81 to 1.09; P=0.44), nor was there any difference in safety outcomes between the two arms (P=0.12).  In addition, prolonging bivalirudin infusion made no difference to clinical outcomes with no change in rates of stent thrombosis or other adverse clinical events (P=0.34).

more…

The Natural History of Takotsubo Cardiomyopathy

4 Nov, 15 | by flee

In the 25 years since first being described, takotsubo (stress) cardiomyopathy has gained increasing recognition as a common clinical entity.  Despite this, our understanding of the natural history of takotsubo cardiomyopathy remains limited.  The International Takotsubo Registry has been gathering data on takotsubo cases since 1998 and this publication describes their findings to date.  Among 1,750 patients with takotsubo cardiomyopathy, 90% were women, the mean age was 66.8 years, and psychiatric or neurological disorders were common (56%). Approximately one-quarter of presentations were triggered by an emotional event, slightly more than one-third by a physical event, and the remainder had no identified trigger. Rates of in-hospital cardiogenic shock and death were similar to rates of these events in a matched cohort of patients presenting with an acute coronary syndrome.  Predictors of in-hospital complications of takotsubo cardiomyopathy included a physical event triggering presentation, acute neurologic or psychiatric diseases, high troponin levels, and a low ejection fraction on admission.  In follow-up, the risk of major adverse events was 9.9% per patient-year and the risk of death was 5.6% per patient-year. In this observational analysis, treatment with an ACE I or ARB was associated with significantly improved prognosis, while no effect was observed with beta-blockade.  Rates of takotsubo recurrence were 1.8% per patient year. more…

Adaptive servo-ventilation increases mortality in systolic heart failure

22 Oct, 15 | by flee

Central sleep-apnea (CSA) with associated Cheyne-Stokes breathing patterns effects up to 40% of patients with low ejection fraction heart failure.   Given that CSA is an independent marker for poor prognosis and mortality, treatment of CSA has been identified as a potential target to improve heart failure outcomes.  This study randomized 1325 patients with low ejection fraction heart failure (mean EF 32%) and a diagnosis of CSA to either overnight adaptive servo-ventilation or guideline directed medical therapy alone. Adaptive servo-ventilation (ASV) is a noninvasive therapy that provides inspiratory pressure support in addition to expiratory positive airway pressure.  Trial patients were followed for a mean of 31 months, with a primary composite end-point of all-cause mortality, hospitalization for heart failure or life-saving cardiac intervention.  Although ASV resulted in a significant decrease in the apnea-hypopnea index among patients in the intervention arm, suggesting the treatment was effective in alleviating CSA.  However, ASV treatment of CSA resulted in increased all-cause mortality (hazard ratio, 1.28; 95% CI, 1.06 to 1.55; P=0.01) and cardiovascular mortality (hazard ratio, 1.34; 95% CI, 1.09 to 1.65; P=0.006) in this population of patients with low ejection fraction. more…

Empagliflozin reduces cardiovascular mortality in Type 2 Diabetics

22 Oct, 15 | by flee

The prevalence of type 2 diabetes is increasing rapidly and represents a major risk factor for cardiovascular disease.  Although glycemic control has been shown to reduce microvascular complications, the effect of glycemic control on macrovascular disease is more limited.  Furthermore, some glucose lowering drugs have been associated with worse cardiovascular outcomes.  Accordingly, ensuring the cardiovascular safety of new diabetic therapies is important. Empaglifozin is one of the first in a new class of drugs that lowers serum glucose levels by decreasing renal glucose reabsorption.  In this study of 7020 patients at high risk of cardiovascular events, patients were randomized to one of two doses of empagliflozin (10 mg or 25 mg) or placebo, as well as standard guideline based diabetic therapy.  The primary outcome was a composite of major adverse cardiovascular events or cardiovascular death.  Although powered as a non-inferiority study, empaglifozin demonstrated statistical superiority as add-on diabetic therapy, significantly reducing the incidence of the primary end-point (10.5% vs. 12.1%, HR 0.86; 95% CI, 0.74 to 0.99; P=0.04 for superiority), including a significant reduction in the risk of death (5.7% and 8.3%, respectively; 32% relative risk reduction).  Use of empaglifozin increased the rates of genital infection (although UTI rates were similar), presumably secondary to the increased amount of glucose present in urine.  No other adverse events were increased with use of empaglifozin. more…

Revascularization in response to identification of elevated high sensitivity troponin in stable patients does not improve outcomes

9 Oct, 15 | by flee

Among patients presenting with an acute coronary syndrome, cardiac troponin assays are the standard method for the identification of patients at high risk who benefit from early revascularization.  With advances in technology, high-sensitivity troponin (hsTn) assays are now available to identify levels of circulating troponin that were previously undetectable.  In this study, the authors sought to determine the impact of prompt revascularization on outcomes among patients with type 2 diabetes and stable ischemic heart disease. Utilizing patients from the BARI 2D study, a total of 2285 patients with stable ischemic heart disease and type 2 diabetes had hsTn measurements taken at baseline and 12 months.  Patients with an elevated hsTn were randomized to prompt revascularization or to ongoing medical therapy.  Over 5 years of follow-up from the point of revascularization, the primary composite end point was death from cardiovascular causes, myocardial infarction, or stroke.  A total of 897 (39.3%) patients were found to have a hsTn above the normal range (≥14 ng/l).  Compared with patients with normal hsTn levels, patients with elevated hsTn levels had a significantly increased risk for adverse events (27.1% vs 12.9% for the composite outcome; P<0.001) Early revascularization in response to elevated hsTn did not improve patient outcomes in this population of patients with stable ischemic heart disease. more…

Leadless pacemakers demonstrate promise

9 Oct, 15 | by flee

Approximately 10% of patients who receive a pacemaker experience complications related to the use of transvenous leads, the surgical pocket, or the pulse generator.  A leadless pacemaker inserted in the right ventricle by way of a transvenous catheter may result in lower complication rates. These leadless pacemakers include electronics, battery, and electrodes all in a single encapsulated device.  In this study, investigators report on a nonrandomized trial of nonsurgical implantation of a leadless cardiac pacemaker in patients who required permanent ventricular pacing.  The primary efficacy end-point was acceptable pacing and sensing thresholds with a safety end-point of device-related serious adverse events at 6 months.  Reporting on data from the initial 300 patients in the study, implantation was successful in 270 (90%) with 6.7% experiencing a device related complication by 6 months including dislodgement requiring percutaneous retrieval (1.7%), cardiac perforation and tamponade (1.2%) and pacing threshold increase requiring retrieval and repositioning (1.3%).  The study also suggested an operator learning curve with a complication rate of 6.8% for the initial 10 cases by each operator as compared with a 3.6% complication rate for subsequent implants. more…

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