Immediate impact of coronary artery bypass graft surgery on regional myocardial perfusion: Results from the Collaborative Pilot Study to Determine the Correlation Between Intraoperative Observations Using Spy Near-Infrared Imaging and Cardiac Catheterization Laboratory Physiological Assessment of Lesion Severity.

Objectives: Coronary artery bypass grafting (CABG) is performed using anatomic guidance. Data connecting the physiologic significance of the coronary vessel stenosis to the acute physiologic response to grafting are lacking. The Collaborative Pilot Study to Determine the Correlation Between Intraoperative Observations Using Spy Near-Infrared Imaging and Cardiac Catheterization Laboratory Physiological Assessment of Lesion Severity study is the first to compare preintervention coronary physiology with the acute regional myocardial perfusion change (RMP-QC) at CABG in a per-graft analysis. Methods: Non-emergent patients undergoing diagnostic catheterization suitable for multivessel CABG were enrolled. Synergy between Percutaneous Coronary Intervention with Taxus score, fractional flow reserve (FFR), instantaneous wave free ratio (iFR), and quantitative coronary angiography was documented in 75 epicardial coronary arteries, with 62 angiographically intermediate and 13 severe stenoses. At CABG, near-infrared fluorescence analysis quantified the relative change (post- vs pregrafting, termed RMP-QC) in the grafted vessel's perfusion territory. Scatter plots were constructed for RMP-QC versus quantitative coronary angiography and RMP-QC versus FFR/iFR. Exact quadrant randomization test for randomness was used. Results: There was no relationship between RMP-QC and quantitative coronary angiography percent diameter stenosis, whether all study vessels were included (P = .949) or vessels with core-lab quantitative coronary angiography only (P = .922). A significant nonrandom association between RMP-QC and FFR (P = .025), as well as between RMP-QC and iFR (P = .008), was documented. These associations remained when excluding vessels with assigned FFR and iFR values (P = .0092 and P = .0006 for FFR and iFR, respectively). Conclusions: The Collaborative Pilot Study to Determine the Correlation Between Intraoperative Observations Using Spy Near-Infrared Imaging and Cardiac Catheterization Laboratory Physiological Assessment of Lesion Severity study demonstrates there is no association between angiographic coronary stenosis severity and the acute perfusion change after grafting; there is an association between functional stenosis severity and absolute increase in regional myocardial perfusion after CABG.

Fractional Flow Reserve/Instantaneous Wave-Free Ratio Discordance in Angiographically Intermediate Coronary Stenoses: An Analysis Using Doppler-Derived Coronary Flow Measurements.

OBJECTIVES: The study sought to determine the coronary flow characteristics of angiographically intermediate stenoses classified as discordant by fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR). BACKGROUND: Discordance between FFR and iFR occurs in up to 20% of cases. No comparisons have been reported between the coronary flow characteristics of FFR/iFR discordant and angiographically unobstructed vessels. METHODS: Baseline and hyperemic coronary flow velocity and coronary flow reserve (CFR) were compared across 5 vessel groups: FFR+/iFR+ (108 vessels, n = 91), FFR-/iFR+ (28 vessels, n = 24), FFR+/iFR- (22 vessels, n = 22), FFR-/iFR- (208 vessels, n = 154), and an unobstructed vessel group (201 vessels, n = 153), in a post hoc analysis of the largest combined pressure and Doppler flow velocity registry (IDEAL [Iberian-Dutch-English] collaborators study). RESULTS: FFR disagreed with iFR in 14% (50 of 366). Baseline flow velocity was similar across all 5 vessel groups, including the unobstructed vessel group (p = 0.34 for variance). In FFR+/iFR- discordants, hyperemic flow velocity and CFR were similar to both FFR-/iFR- and unobstructed groups; 37.6 (interquartile range [IQR]: 26.1 to 50.4) cm/s vs. 40.0 [IQR: 29.7 to 52.3] cm/s and 42.2 [IQR: 33.8 to 53.2] cm/s and CFR 2.36 [IQR: 1.93 to 2.81] vs. 2.41 [IQR: 1.84 to 2.94] and 2.50 [IQR: 2.11 to 3.17], respectively (p > 0.05 for all). In FFR-/iFR+ discordants, hyperemic flow velocity, and CFR were similar to the FFR+/iFR+ group; 28.2 (IQR: 20.5 to 39.7) cm/s versus 23.5 (IQR: 16.4 to 34.9) cm/s and CFR 1.44 (IQR: 1.29 to 1.85) versus 1.39 (IQR: 1.06 to 1.88), respectively (p > 0.05 for all). CONCLUSIONS: FFR/iFR disagreement was explained by differences in hyperemic coronary flow velocity. Furthermore, coronary stenoses classified as FFR+/iFR- demonstrated similar coronary flow characteristics to angiographically unobstructed vessels.

Noninvasive Quantification of Blood Flow in Epicardial Coronary Arteries, Coronary Artery Bypass Grafts, and Anastomoses.

OBJECTIVE: Direct flow measurement in native epicardial coronary arteries, bypass conduits, and anastomoses is severely limited by the invasiveness and inaccuracy of existing technologies. As a result, less than 25% of patients undergoing coronary artery bypass grafting (CABG) worldwide have any intraoperative evaluation performed. A simple, accurate, and noninvasive technology to directly quantify blood flow and rheology surrounding anastomotic sites is a critical unmet need in CABG. METHODS: Existing technology limitations drove development of a different technology solution. With an optical physics approach, flow in conduits and tissue can be quantified in real time with nonionizing broad-spectrum imaging as well as temporal and spatial analyses. Cardiac motion, calibration, and combining anatomy + physiology in imaging were challenges requiring solutions. RESULTS: This patented imaging technology was developed and tested in an established porcine cardiac experimental model and in clinical proof-of-concept studies. Flow velocities and flows in epicardial coronary arteries vary physiologically with the cardiac cycle and with acute ischemia, as predicted by previous studies using traditional technologies. Imaging data are captured from a 30-cm viewing distance, analyzed and displayed in real time as a video. The field of view enables capture of flow in the proximal and distal epicardial coronary, the conduit, at the anastomosis and in the distal myocardium simultaneously. CONCLUSIONS: Rheologic flow interaction between conduit and native coronary at the anastomosis remains the most poorly understood technical aspect of CABG. A noninvasive, noncontact, no-risk imaging technology as simple as a snapshot can provide this critical physiologic information, validate and document intraoperative quality, and improve even further CABG outcomes.

Improving quality and outcomes of coronary artery bypass grafting procedures.

The evolution in the approach, clinical care and outcomes of ischemic heart disease, has been dramatic over the past decade. Optimizing medical therapy initially and throughout the care delivery process has been transformative. The addition of new physiologic data to the traditional anatomic framework for diagnosis and therapy of more extensive stable ischemic heart disease (SIHD) enables quality and outcomes improvements in this patient population overall and in the patient subsets of acute coronary syndrome and SIHD. In patients undergoing coronary artery bypass grafting (CABG), these developments have changed the objective goal of surgical revascularization over this time interval. This review discusses the opportunities for quality and outcomes improvement in CABG, in the context of SIHD overall.

Allen's test: does it have any significance in current practice?

Percutaneous coronary intervention (PCI) performed through transradial access (TRA) has been consistently demonstrated to be safer than transfemoral access (TFA), mainly due to significantly reduced bleeding and vascular complications. Despite demonstrating better patient safety, acceptance of TRA as an access site of choice has remained low, with geographical variations. One of the relative contraindications to performing PCI through TRA is an abnormal Allen's test (AT), in which case the access site is usually switched to TFA. Bleeding and vascular complications are the "Achilles heel" for interventions through the TFA. The use of the AT is controversial given its low sensitivity in assessing both the collateral circulation of the hand and predicting ischemic complications. In this article, we present interesting data from the congenital heart and trauma literature that lead us to suggest the AT is an inadequate test to assess the collateral circulation of the hand. We think the case for its routine guideline-driven use is flawed.

Radiation dose during coronary angiogram: relation to body mass index.

OBJECTIVE: Ionising radiation based diagnostic and therapeutic cardiology and radiology procedures are very common in present day medical practice and are one of the largest medical sources of radiation to humans. The risk to health from radiation has been extensively documented. Obesity is becoming epidemic not only in the western world, but also in developing countries. In the present study we investigated if a patient's Body Mass Index (BMI) has an effect on the radiation dose received by the patient and operator during diagnostic coronary angiography (CAG). METHODS: We analysed data of 3678 consecutive patients who underwent CAG from September 2007 to April 2010 in our cardiac catheter laboratory. Trans-radial access was used in 622 patients, whereas 3056 patients underwent CAG through trans-femoral route. We calculated the radiation dose in dose area product (DAP) units and correlated it with body mass index, screening time, procedure time, contrast volume, vascular access route and individual operator. RESULTS: Among the explored parameters, body mass index had the most significant association with the radiation dose during the procedure. Despite having similar procedure times and contrast doses, patients with increased BMI received much higher radiation dose during CAG. We also found the left anterior oblique (LAO) caudal and LAO cranial views produced the biggest increase in radiation dose in patients with a high BMI. There was no inter-operator variability. CONCLUSION: Obese patients require more than double the radiation dose in comparison to those with normal BMI. The operator should be aware of the increased dose of radiation required when performing CAG in patients with increased BMI, and especially in LAO cranial and caudal views.

Pathophysiology of paradoxical embolism: evaluation of the role of interatrial septum anatomy based on the intracardiac echocardiography assessment of patients with right-to-left shunting.

BACKGROUND: Detailed anatomic variants of the interatrial septum in patients with right-to-left shunt and contribution of specific anatomies to the risk of ischaemic recurrences has not yet been comprehensively classified. OBJECTIVE: To report a classification of the anatomic variants of the interatrial septum as observed by intracardiac echocardiography and its correlation with clinical and functional characteristics. METHODS: We retrospectively reviewed the medical and instrumental data of 520 consecutive patients (mean age 44±15. 5 years, 355 women) who had over a 10-year period undergone intracardiac echocardiography and right-to-left shunt catheter-based closure. The four main features used to analyse were: (a) diameter of the oval fossa, (b) presence and length of the channel, (c) presence and degree of atrial septal aneurysm, and (d) rim thickness. The presence of Eustachian valve was also tabulated. RESULTS: The combinations of interatrial septum anatomical features were classified into six main anatomical subgroups. Recurrent embolism, multiple ischaemic foci on brain magnetic resonance imaging, high grade shunt, and permanent shunt before transcatheter closure procedure were associated with type 2, type 4, and type 6. Type 4 anatomical subtype (OR 4.1, 1.5-8 [95% CI], p<0.001) and type 2+presence of Eustachian valve (OR 4.3, 1.6-9 [95% CI], p<0.001) were the strongest predictors of recurrent ischaemic events before transcatheter closure. CONCLUSION: Our study showed that interatrial septum anatomy greatly differs among patients with right-to-left shunt, as well as the risk of ischaemic recurrences in different anatomies.

Cannabis-associated myocardial infarction in a young man with normal coronary arteries.

BACKGROUND: The use of cannabis is not usually regarded as a risk factor for acute coronary syndrome. However, several cases of myocardial infarction (MI) associated with cannabis use have been reported in the scientific literature. The etiology of this phenomenon is not known. OBJECTIVES: To present a case of cannabis-associated MI in which atherosclerotic coronary disease was excluded as a potential etiology by intravascular ultrasound examination, and briefly review the other possible mechanisms by which this effect may be mediated. CASE REPORT: We present the case of a previously healthy 21-year-old man who regularly smoked cannabis and presented to the Emergency Department with ST-elevation myocardial infarction after participating in a sport. He was also a cigarette smoker, but had no other conventional cardiovascular risk factors. At coronary angiography, a large amount of thrombus was found in the left anterior descending coronary artery. He recovered with medical treatment, and subsequent intravascular ultrasound examination showed no evidence of atherosclerosis at the site of the thrombus. CONCLUSION: Cannabis-associated MI is increasingly recognized. The etiology is unclear, but we believe this is the first report of the phenomenon where atherosclerotic plaque rupture has been excluded as the cause with a high degree of confidence.

Post-traumatic internal mammary artery pseudoaneurysm: A rare complication of pericardiocentesis.

Before the advent of ultrasound, percutaneous pericardiocentesis was associated with relatively high mortality and complication rates (6% and 20-50%, respectively) [1-3]. Ultrasound (US)-guided pericardiocentesis has dramatically decreased the incidence of complications by direct visualization of the heart and other adjacent vital structures. US helps localize the size and location of the pericardial effusion, measure the distance from the chest wall, localize adjacent, vital organs, and determine the optimal access site to the effusion. We report a case of posttraumatic internal mammary artery pseudoaneurysm, a rare complication of pericardiocentesis.

Fractional flow reserve-guided coronary bypass surgery: should surgeons use it?

PURPOSE OF REVIEW: Physiology-based evaluation in stable ischemic heart disease is transforming percutaneous cardiovascular intervention (PCI). Fractional flow reserve (FFR)-guided PCI is associated with more appropriate and beneficial outcomes at lower costs. The surgical community can no longer ignore this development. We review evidence for the rationale, practicality and appropriateness of FFR-guided coronary artery bypass grafting (CABG), as compared with the current conventional, anatomy-based strategy for surgical revascularization. RECENT FINDINGS: Physiologic evaluation links the nature (anatomic or functional) of coronary stenoses to the perfused myocardium supplied by the target vessel and challenges the use of anatomy as the sole criterion for revascularization intervention. In CABG, a functional perfusion deficit/ischemia identifies myocardial territories that would physiologically benefit from revascularization by grafting beyond the functional stenosis. Conversely, deliberately not grafting beyond an anatomic stenosis would dramatically change the procedure of CABG. Recent studies of functionally guided revascularization (PCI or CABG) support this approach, while recent trials of PCI vs. CABG demonstrated a late survival advantage with anatomy-based CABG. Finally, new intraoperative imaging technologies are elucidating the physiologic consequences of surgical revascularization in real time, yielding insights into resolving this dilemma. SUMMARY: Physiologic-based revascularization is challenging our thinking about the historic strategy for CABG. Understanding better the physiologic consequences of revascularization will drive the evolution of CABG in the future.

Drug-eluting stents versus bare metal stents for narrowing in saphenous vein grafts.

Conflicting data exist regarding an advantage of drug-eluting stents (DES) over bare metal stents (BMS) in catheter-based treatment of saphenous vein graft (SVG) stenoses. This study was undertaken to compare the efficacy of these modalities in that lesion subset. The DES group consisted of 138 cases with 183 lesions (sirolimus-eluting stents, n = 117; paclitaxel-eluting stents, n = 66) and the BMS group consisted of 344 cases with 478 lesions that were followed to 1 year. We examined a composite end point that comprised death, Q-wave myocardial infarction, and target lesion revascularization. More BMS were deployed per patient (p <0.001) and the diameters of BMS deployed was significantly greater (p <0.001). Peak postprocedure values of creatine kinase-MB (p = 0.003) and troponin I (p = 0.05) were higher in BMS. At 1 year there was no significant superiority of DES over BMS with regard to hard end points (death and Q-wave myocardial infarction). In conclusion, this study indicates that both DES and BMS for SVG disease provide acceptably safe and efficacious results, but unlike the case in native coronary arteries, DES use does not reduce the frequency of the need for repeat revascularization.

Observations and outcomes of definite and probable drug-eluting stent thrombosis seen at a single hospital in a four-year period.

Stent thrombosis (ST) is a major safety concern after drug-eluting stent (DES) deployment, resulting in significant morbidity and mortality. The goal of this study was to examine the incidence, timing, clinical correlates, and outcomes after DES thrombosis in a real-world population. A retrospective analysis of 8,402 patients who underwent percutaneous coronary intervention and received a DES was performed. After DES implantation, 84 definite (DST) and 127 probable ST events occurred. The incidence of early DST was 0.8%, late DST was 0.4%, and very late DST was 0.4%. Multivariate analysis showed that a history of diabetes mellitus, myocardial infarction during admission, number of stents, and DES placement in a restenotic lesion were independently associated with DST. The incidence of early definite or probable ST (DPST) was 1.9%, late DPST was 1.4%, and very late DPST was 0.7%. Multivariate analysis showed that a history of diabetes, myocardial infarction during admission, cardiogenic shock, number of stents, and DES use in a restenotic lesion were independently associated with DPST. Both types of ST were associated with significantly higher rates of all-cause death, Q-wave myocardial infarction, and revascularization up to 24 months after DES implantation. In conclusion, ST after DES implantation in contemporary practice continues to occur from 30 days to 2 years at a rate > or =0.36%/year and is associated with high rates of morbidity and mortality. Diabetes mellitus, myocardial infarction, and DES use in a restenotic lesion were strongly associated with DST; therefore, careful consideration should apply when deploying a DES in these populations.

Outcomes after sirolimus- and paclitaxel-eluting stent implantation in patients with insulin-treated diabetes mellitus.

Insulin-treated diabetic patients undergoing drug-eluting stent implantation are prone to high rates of adverse cardiac events. The efficacy of the sirolimus- (SES) and paclitaxel-eluting stent (PES) in this population was analyzed. Registry data for 434 consecutive patients with insulin-treated diabetes who underwent SES or PES implantation were analyzed. The end point, major adverse cardiac events (MACEs) at 1 year, was high for patients with SESs and PESs (20.6% vs 20.2%; p=0.91). Cox regression and propensity analysis were used to compare outcomes. The adjusted hazard ratio (HR) for MACEs according to stent type (Cox model) was 1.0 (95% confidence interval [CI] 0.64 to 1.76, p=0.82). The propensity score-adjusted (C statistic=0.66) HR was 0.95 (95% CI 0.56 to 1.61, p=0.84). Stent thrombosis rates were relatively high at 2.0% for SESs and 1.5% for PESs (p=0.49). The propensity score-adjusted HR for stent thrombosis was 2.7 (95% CI 0.31 to 23.6, p=0.37). In conclusion, SESs and PESs are similarly efficacious in insulin-treated diabetic patients. The high MACE and stent thrombosis rates are of concern. Additional studies in this group of patients are required to determine the optimal mode of revascularization and minimize the overall stent thrombosis rate.

Adjunct thrombus aspiration reduces mortality in patients undergoing percutaneous coronary intervention for ST-elevation myocardial infarction with high-risk angiographic characteristics.

Routine aspiration thrombectomy (AT) in percutaneous coronary intervention for patients with ST-segment elevation myocardial infarction (STEMI) has not proved effective in randomized trials. However, in patients undergoing primary percutaneous coronary intervention with severely reduced flow or visible thrombus, AT remains an intuitively attractive option. The use of adjunctive AT in a high-risk cohort of 158 consecutive patients with STEMI and Thrombolysis In Myocardial Infarction (TIMI) 0 to 1 flow or visible thrombus on baseline angiography was examined. Of these, 80 patients underwent AT as an adjunct to primary percutaneous coronary intervention, and 78 underwent percutaneous coronary intervention without AT (non-AT). TIMI 3 flow rates, residual thrombus after percutaneous coronary intervention, and major adverse cardiac events (mortality and nonfatal Q-wave myocardial infarction) at 30 days, 6 months, and 1 year were compared. Baseline characteristics were similar between groups. The AT group more frequently achieved TIMI 3 flow after the intervention (91.3% AT vs 67.9% non-AT; p <0.001) and had less residual thrombus (7.5% AT vs 19.2% non-AT; p = 0.03). AT was associated with reduced major adverse cardiac events at 6 months (6.8% AT vs 24.0% non-AT; p = 0.004) and 1 year (16.6% AT vs 29.2% non-AT; p = 0.009), and decreased mortality rates in the AT group at 6 months (5.4% AT vs 21.3% non-AT; p = 0.004) and 1 year (7.7% AT vs 26.2% non-AT; p = 0.005). In conclusion, for patients with STEMI and TIMI 0 or 1 flow or visible thrombus on baseline angiography, AT was associated with increased TIMI 3 flow rates, decreased residual thrombus, and decreased clinical events, including mortality.