Examining the performance of engineering treatment evaluation methodologies using the hypothetical treatment and actual treatment settings.

The selection of treatment evaluation methodology is paramount in determining reliable crash modification factors (CMFs) for engineering treatments. A lack of ground truth makes it cumbersome to examine the performance of treatment evaluation methodologies. In addition, a sound methodological framework is critical for evaluating the performances of treatment evaluation methodologies. In addressing these challenges, this study proposed a framework for assessing treatment evaluation methodologies by hypothetical treatments with known ground truth and actual real-world treatments. In particular, this study examined three before-after treatment evaluation approaches: 1) Empirical Bayes, 2) Simulation-based Empirical Bayes, and 3) Full Bayes methods. In addition, this study examined the Cross-Sectional treatment evaluation methodology. The methodological framework utilized five datasets of hypothetical treatment with known ground truth based on the hotspot identification method and a real-world dataset of wide centerline treatment on two-lane, two-way rural highways in Queensland, Australia. Results showed that all the methods could identify the ground truth of hypothetical treatments, but the Full Bayes approach better predicts the known ground truth compared to Empirical Bayes, Simulation-based Empirical Bayes, and Cross-Sectional methods. The Full Bayes approach was also found to provide the most precise estimate for real-world wide centerline treatment along rural highways compared to other methods. Moreover, the current study highlighted that the Cross-Sectional method offers a viable estimate of treatment effectiveness in case the before-period data is limited.

Influence of segmentation approaches on the before-after evaluation of engineering treatments: A hypothetical treatment approach.

The segmentation of highways is a fundamental step in estimating crash frequency models and conducting a before-after evaluation of engineering treatments, but the effects of segmentation approaches on the engineering treatment evaluations are not known very well. This study examined the effects of segmentation approaches on the before-after evaluation of engineering treatments. In particular, this study evaluated four segmentation approaches by applying the Empirical Bayes technique to a dataset for which the ground truth was known. Four segmentation approaches included Highway Safety Manual (HSM), Fixed (kilometre post), Fisher's, and K-means segmentation. This study utilized a 440 km stretch of rural two-lane two-way highway in Queensland, Australia, to prepare a dataset with known ground truth. The treatment under evaluation was a hypothetical treatment, which should yield a crash modification factor (CMF) of 1. For assigning hypothetical treatment, a total of fifteen datasets were prepared, including ten datasets based on the random assignment and five datasets based on the hotspot identification method. Following the before-after evaluation using the Empirical Bayes technique, the results showed that HSM and Fixed segmentation approaches predict the ground truth in both dataset types. From random assignment datasets, the estimated CMFs using HSM, Fixed, Fisher's, and K-means segmentation approaches deviated from the true CMF (i.e., 1) by 2.32 %, 5.30 %, 6.08 %, and 8.62 %, respectively. In the case of hotspots, the corresponding deviations of CMFs were 8.57 %, 9.37 %, 28.84 %, and 35.43 %, respectively. Overall, HSM segmentation best identified the actual treatment effect, followed by the Fixed segmentation. If the variables to define homogeneity for HSM segmentation are limited, then Fixed segmentation can yield reliable crash modification factors from the before-after treatment evaluations than the crash-based segmentation approaches.

Comparison of Tricuspid Regurgitation Severity Between Cardiac Resynchronization Therapy Versus Right Ventricular Pacing in Patients With Chronic Obstructive Pulmonary Disease.

Background: Right ventricular (RV) lead placement can worsen tricuspid regurgitation (TR). TR is known to be associated with lower survival irrespective of left ventricular ejection fraction (LVEF) or pulmonary hypertension (PH). Patients with chronic obstructive pulmonary disease (COPD) often have PH and pre-existent TR with higher morbidity and mortality from worsening TR. Prior studies are lacking to indicate if cardiac resynchronization therapy (CRT) may be more beneficial in lessening TR in COPD patients. Therefore, we sought to study if patients with COPD will have less TR with CRT versus non-CRT devices. Methods: We performed a retrospective, single-center analysis on 154 COPD patients (mean age = 71.69 ± 10.58, males = 54.14%) that required single-chamber (n = 27), dual-chamber (n = 90), or CRT (n = 37) devices. TR severity, LVEF and right ventricular systolic pressure (RVSP) were evaluated by two cardiologists in a blinded fashion. Analysis of variance (ANOVA) and Chi-square tests were applied for continuous and categorical variables respectively. The primary endpoint was a change in the severity of TR comparing pre-device versus post-device echocardiogram. Secondary endpoints included changes in LVEF and RVSP. Results: COPD patients, who underwent a CRT device had a significantly lower incidence of worsening TR (16%) when compared to single- (37%) (P = 0.001) and dual-chamber devices (30%) (P = 0.02). The increase in RVSP was similar between the groups. There was an expected improvement in LVEF in the CRT group. Conclusions: COPD patients receiving a CRT device were least likely to have worsening TR, compared to single- or dual-chamber devices. Since both COPD and progression in TR may result in poor outcomes, our study may suggest that an upfront strategy of CRT rather than a single- or dual-chamber device may be more beneficial in COPD patients, especially with pre-existent TR.

Pathophysiological factors contributing to fractional flow reserve and instantaneous wave-free ratio discordance.

The diagnostic accuracy and clinical benefits of instantaneous wave-free ratio (iFR) compared to fractional flow reserve (FFR) have been well-established in the literature. Despite the advantages of non-hyperemic pressure indices, approximately 20% of iFR and FFR measurements are discordant. Efforts have been made to establish the mechanisms as well as identify causative factors that lead to such a discordance. Recent studies have identified many factors of discordance including sex differences, age differences, bradycardia, coronary artery stenosis location, elevated left ventricular end-diastolic pressure, and diastolic dysfunction. Additionally, discordance secondary to coronary artery microcirculation dysfunction, as seen in diabetics and patients on hemodialysis, has sparked interest amongst experts. As more interventional cardiologists are utilizing iFR independent of FFR to guide percutaneous coronary intervention an emphasis has been placed on identifying factors leading to discordance. The aim of this review is to outline recent studies that have identified factors of FFR and iFR discordance.

Triple Antithrombotic Therapy (Triple Therapy) After Percutaneous Coronary Intervention in Chronic Anticoagulation: A Literature Review.

Selecting anticoagulation therapy for patients with atrial fibrillation and coronary artery disease has always been challenging for physicians. The treatment modalities have evolved with time. Oral anticoagulation with warfarin was used in the initial era of stenting to prevent stent thrombosis, and dual antiplatelet therapy is the current recommendation. Triple anticoagulation therapy, i.e., aspirin, P2Y12 inhibitor, and oral anticoagulation, is associated with higher bleeding episodes and mortality compared to the combination of an anticoagulant and a P2Y12 inhibitor.

Mortality in Patients of COVID-19 Infection: Biochemical Markers and its Cut-off Values for Predicting Outcome.

OBJECTIVE: To determine the efficacy and cut-off values of C-reactive protein (CRP), lactate dehydrogenase (LDH), serum ferritin, and D-dimer for predicting mortality of COVID-19 infection. STUDY DESIGN: Observational study. PLACE AND DURATION OF STUDY: Department of Medicine, Jinnah Hospital, Lahore from January to May 2021. METHODOLOGY: Serum CRP, LDH, ferritin, and D-dimer were measured in patients with moderate to severe COVID-19 infection at admission. Patients were followed for in-hospital disease outcome. ROC curve was used to determine area under curve (AUC) and cut-off values of biomarkers, followed by multi-variate analysis by logistic regression. RESULTS: In 386 patients, male to female ratio was 1.47/1 (230/156); and mean age was 54.03 ± 16.2 years. Disease was fatal in 135 (35%) patients. AUC for mortality was 0.730 for LDH, 0.737 for CRP, 0.747 for ferritin and 0.758 for D-dimer. Mortality was higher with LDH ≥400 U/ml, Odds Ratio (OR) 5.37 (95% CI 3.01-9.57: p = 0.001), CRP ≥30 ng/L, OR 4.30 (95% CI 2.11-8.74: p = <0.001), serum ferritin ≥200 ng/ml, OR 4.13 (95% CI 1.05-16.2: p = 0.02), and D-dimer ≥400 ng/ml, OR 2.72 (95% CI 1.06-7.01: p = 0.03) with 2 log likelihood of 131.54 for predicting disease outcome with 71.7% accuracy in multi-variate analysis. CONCLUSION: Elevated serum CRP, LDH, ferritin and D-dimer are associated with higher mortality in patients of COVID-19 infection. Serum CRP ≥30ng/ml, LDH ≥400 U/L, ferritin ≥200 ng/ml and D-dimer ≥400 ng/ml can predict fatal outcome in COVID-19 patients. Key Words: C-reactive protein (CRP), COVID-19 infection, D-dimer, Ferritin, Lactate dehydrogenase (LDH), Mortality.

Use of the CHA2DS2-VASc Score in Assessing Transradial Approach Failure.

BACKGROUND: Radial access is now considered the preferred approach for coronary angiography and percutaneous coronary intervention because of the low risk of vascular complications. However, radial access failure is not uncommon, leading to crossover to a different access site. The CHA2DS2-VASc score is used to estimate stroke risk in patients with atrial fibrillation. Our study aimed to assess the CHA2DS2-VASc score in predicting failure of the transradial approach, resulting in crossover to transfemoral access (TFA) for coronary angiography. METHODS: We performed a single-center, non-randomized, retrospective study. The study included 1775 patients who underwent coronary angiography with or without subsequent percutaneous intervention between July 2018 and October 2019. The study population was divided into three groups based on the CHA2DS2-VASc score: low (≤2), intermediate (3-4), and high score (≥5) groups. The association between the CHA2DS2-VASc score and radial access failure was evaluated and compared between the groups. RESULTS: A total of 197 patients (11.1%) had crossover to the femoral artery. A large percentage of patients (19.2%) had radial access failure in the high CHA2DS2-VASc score group (≥5) compared with 12.5% in the intermediate score group (3-4) and only 6.3% in the low score group (≤2). The highest crossover rate (42.9%) was observed in patients with a CHA2DS2-VASc score of 8. Higher CHA2DS2-VASc scores were also associated with increased fluoroscopy time, contrast administration, and radiation exposure. CONCLUSION: The CHA2DS2-VASc score can predict failure of the transradial approach, with a score of ≥5 having the highest correlation of failure requiring crossover to TFA.

Comparison of Transcatheter Aortic Valve Implantation Outcomes Between Normal-Flow, Low-Gradient Severe Aortic Stenosis and Normal-Flow, High-Gradient Severe Aortic Stenosis.

BACKGROUND: Normal flow low gradient severe aortic stenosis (NFLG-AS) with preserved ejection fraction is the most prevalent form of low gradient severe aortic stenosis. Despite the increased prevalence, the clinical outcomes and management strategy of NFLG-AS remain controversial. Therefore, our study aimed to evaluate transcatheter aortic valve implantation (TAVI) outcomes of patients with NFLG-AS compared with normal flow high gradient severe aortic stenosis (NFHG-AS). METHODS: We performed a retrospective analysis of 394 patients who underwent TAVI between January 2011 to September 2020. Among 394 patients, 232 patients had NFLG-AS, and 162 patients had NFHG-AS. The primary outcomes included all-cause mortality and cardiovascular mortality. In addition, multiple secondary outcomes were evaluated, including stroke, myocardial infarction, duration of hospital stay, new-onset atrial fibrillation, temporary or permanent pacemaker requirement, major bleeding, blood transfusion, vascular complications, acute kidney injury, hemodialysis requirement, symptom improvement, and repeat hospitalizations due to any cardiac disease. RESULTS: The cumulative six months incidence of all-cause mortality and cardiovascular mortality were similar between and NFLG-AS and NFHG-AS (4.32% vs. 5.17%, P = 0.71 and 2.47% vs. 2.59%, P = 0.94 respectively). There was no difference in the rates of stroke, myocardial infarction, duration of hospital stay, new-onset atrial fibrillation, temporary or permanent pacemaker requirement, major bleeding, blood transfusion, vascular complications, acute kidney injury, hemodialysis requirement, and symptom improvement between the two groups. However, patients with NFLG-AS compared to NFHG-AS had more frequent cardiac-related repeat hospitalizations (19.14% vs. 11.64%, P = 0.04%). CONCLUSION: There was no significant difference in all-cause mortality and cardiovascular mortality between NFLG-AS and NGHG-AS six months post-TAVI. However, patients undergoing TAVI with NFLG-AS had significantly higher rates of cardiac-related repeat hospitalizations.

A simulation-based empirical bayes approach: Incorporating unobserved heterogeneity in the before-after evaluation of engineering treatments.

The Empirical Bayes approach for before-after evaluation methodology utilizing the negative binomial model does not account well for unobserved heterogeneity. Building on the Empirical Bayes approach, the objective of this study was to propose a framework to accommodate unobserved heterogeneity in before-after countermeasure evaluation. In particular, this study has proposed a simulation-based Empirical Bayes approach by applying the panel random parameters negative binomial model with parameterized overdispersion (PRNB-PO) to evaluate the effectiveness of engineering treatments. The proposed framework has been tested for the wide centerline treatment (WCLT) on rural two-lane two-way highways in Australia. The empirical analysis included 511 km of WCLT treated highways in a before-after evaluation within a time period of 2010 - 2018 and 430 km of reference sites in Queensland, Australia. The PRNB-PO models outperformed the traditional negative binomial models in terms of goodness-of-fit and prediction performance for total injury crashes, and fatal and serious injury (FSI) crashes. The simulation-based Empirical Bayes approach using the PRNB-PO model resulted in more precise estimates of crash modification factors than the standard Empirical Bayes approach. The WCLT is found to result in significant reductions in total injury crashes by 28.21% (95% confidence interval (CI) = 22.92 - 33.50%), FSI crashes by 13.90% (95% CI = 6.99 - 20.81%), and head-on crashes by 25.45% (95% CI = 14.87 - 36.03%). Overall, WCLT is an effective engineering treatment and should be considered a low-cost countermeasure on rural two-lane two-way highways.

Heme Effects in Lowering Patient Discomfort in Radial Artery Verapamil Injection.

BACKGROUND: The primary objective of this study was to evaluate whether diluting verapamil with heme as compared to normal saline reduces patient discomfort during radial artery injection. Following radial artery access, verapamil is frequently administered to reduce the incidence of radial artery spasm. The injection of verapamil via the radial artery is associated with a temporary "burning" discomfort. It has been hypothesized that the dilution of verapamil with heme rather than saline leads to less patient discomfort during administration. METHODS: This prospective, single-center, randomized study enrolled patients undergoing coronary angiography via radial artery access between August 2017 and April 2018. Patients were randomized 1:1 to receive either verapamil/heme or verapamil/saline administration. Patient discomfort was assessed at the time of injection, and 1-h post procedure. RESULTS: A total of 214 patients were enrolled in the study. Of these, 103 patients were included in the verapamil/heme group and 100 in the verapamil/saline group. For the primary objectives, there were no statistically significant differences in patient discomfort at the time of verapamil injection (P = 0.15), or 1-h post injection (P = 0.48). However, in the verapamil/heme group, there was a trend towards a lower post-injection pain score (M = 2.83, standard deviation (SD) = 3.18) compared to the verapamil/saline group (M = 3.48, SD = 3.01) (P = 0.15). CONCLUSION: There was no significant difference in immediate or 1-h post-procedure patient discomfort with verapamil diluted with heme as compared to dilution with saline. While there was a trend towards lower immediate patient discomfort in the verapamil/heme group, larger studies are needed to further evaluate this trend.

Iatrogenic Arteriovenous Fistula Secondary to Coronary Artery Dissection Caused by Contrast Injection Into a Chronically Occluded Right Coronary Artery.

Coronary arteriovenous fistulas and coronary cameral fistulas are rare anomalies that involve the abnormal communication between a coronary artery and a venous structure, such as a coronary vein or a right-sided cardiac chamber. Iatrogenic coronary arteriovenous fistulas and coronary cameral fistulas can be uncommon complications of coronary artery angiography and intervention. Acquired coronary arteriovenous fistulas that develop during percutaneous coronary intervention of chronic total occlusions have been previously reported in the literature. However, a coronary arteriovenous fistula resulting from contrast injection into a chronically and totally occluded right coronary artery during diagnostic coronary angiography is very rare. We present a unique case of a contrast-induced iatrogenic right coronary dissection leading to a coronary arteriovenous fistula communicating to the right atrium through the middle cardiac vein.

Successful Low-Dose tPA for Mechanical Mitral Valve Thrombosis in a Patient with Postinfarction Contained Left Ventricular Free Wall Rupture.

Prosthetic valve thrombosis is a potentially life-threatening complication diagnosed by a combination of clinical features and imaging modalities, but the optimal management in high bleeding risk patients remains controversial. Current treatment options for prosthetic valve thrombosis included surgery, thrombolytic therapy, and anticoagulation. We present a very unusual case of a patient with a recent ST-elevation myocardial infarction complicated by contained left ventricle free wall rupture and mechanical mitral valve thrombosis. Deemed a high surgical risk candidate, low-dose tissue plasminogen activator was used despite significant bleeding risk from contained left ventricle free wall rupture, which resulted in resolution of the thrombus. To the best of our knowledge, this is the first report of successful thrombolytic therapy for prosthetic mechanical mitral valve thrombosis in a patient with recent postmyocardial infarction contained left ventricular free wall rupture.

Effect of Atrioventricular Dyssynchrony on Impella Hemodynamics: Mechanism and Its Clinical Implications.

The physiologic importance of atrial systole and atrioventricular (AV) synchrony in maintaining cardiac performance is well established. However, the role of AV synchrony in maintaining adequate Impella output has not been fully evaluated. Despite the common belief that AV dyssynchrony does not affect Impella output, given that Impella is a continuous flow device, recent reports indicate that AV dyssynchrony can lead to low Impella output in patients with cardiogenic shock complicated by complete heart block. Temporary transvenous pacing without establishing AV synchrony may fail to improve Impella hemodynamics; therefore, understanding the mechanism of low Impella output in AV dyssynchrony and promptly restoring AV synchrony may improve Impella output in such cases and lead to better outcomes.

Successful Rescue Intervention of Internal Mammary Artery Anastomotic Site Acute Graft Failure With Direct New Generation Covered Stenting.

Acute, perioperative myocardial infarction (MI) from acute left internal mammary artery (LIMA) to left anterior descending (LAD) graft failure immediately following coronary artery bypass grafting (CABG) surgery is associated with significantly increased in-hospital mortality. The leading etiology of such acute graft failure is acute thrombosis, dissection, spasm, anastomosis failure or no-reflow phenomenon. Repeat bypass surgery carries incremental risk and may not be feasible in hemodynamically unstable patients. Traditional percutaneous coronary intervention (PCI), with or without stent placement is sometimes used in such cases; however, graft anatomy and lesion location increase procedural complexity and challenge technical feasibility. This is particularly true of the LIMA to LAD graft anastomosis, where PCI carries the risk of anastomotic site perforation or avulsion. Therefore, the best revascularization strategy for such a lesion involving the LIMA to LAD graft anastomosis in the immediate perioperative period remains unknown. We present a case of 75-year-old male who suffered an acute MI complicated by cardiogenic shock less than 24 h after two-vessel CABG. Selective angiography revealed acute LIMA to LAD anastomotic site closure, posing a risk for perforation if treated with traditional angioplasty or stenting. We successfully performed rescue PCI, by directly deploying a PK Papyrus covered stent (Biotronik, Berlin, Germany) across the anastomosis. Our case report describes the upfront (rather than a bail out) use of the new covered stent as a novel revascularization strategy to treat "perforation prone" LIMA to LAD anastomotic site acute graft failure.

Association of Echocardiographic Diastolic Dysfunction with Discordance of Invasive Intracoronary Pressure Indices.

Instantaneous wave-free ratio (iFR)-guided coronary revascularization has similar clinical outcomes compared to fractional flow reserve (FFR)-guided revascularization strategy. However, some studies have shown a discordance of around 20% between iFR and FFR. Although various factors have been reported in the literature to affect pressure indices and lead to such discordance, there is a paucity of data regarding the effect of diastolic dysfunction on functional assessment of coronary arteries. Our study aimed to investigate whether there was an association between echocardiographic left ventricular diastolic dysfunction and iFR/FFR discordance. This retrospective observational study evaluated 100 patients with angiographically intermediate coronary stenosis (50-70%) who underwent physiological testing with iFR and FFR. Transthoracic echocardiograms were reviewed to assess echocardiographic indices of diastolic function. The study population was divided into two groups based on diastolic function. iFR and FFR discordance was measured in each group and compared to evaluate the statistical difference. The mean age of the study population was 66.22 ± 10.02 years. Discordance between iFR and FFR was seen in 45.16% of patients with diastolic dysfunction compared to 24.64% of patients with normal diastolic function (p = 0.04). Multivariable logistic regression analysis indicated that echocardiographic E/e' was independently associated with iFR/FFR discordance (p = 0.02). Left ventricular diastolic dysfunction is a significant factor that can lead to discordance between iFR and FFR and should be taken into account during coronary physiological testing.

Positional changes leading to transient ischaemia in a patient with neuroendocrine carcinoma of the lung.

Coronary spasm in carcinoid heart disease has an incidence of 10%, but is rare in patients with neuroendocrine tumours without carcinoid heart disease. We present a rare case of right coronary artery spasm and ST elevations secondary to a neuroendocrine carcinoma of the lung, uniquely provoked by positional changes. Our patient is a 55-year-old man with recurrent ST-elevation myocardial infarction secondary to coronary vasospasm that was diagnosed with neuroendocrine carcinoma of the lung. We believe his positional coronary spasm episodes were likely due to intermittent tumour compression from changes in body position. Our case highlights positional coronary spasm as a previously unreported and potentially early manifestation of neuroendocrine carcinoma of the lung.

Comparing the Efficacy of Patelet-rich Plasma (PRP) versus Tranexamic Acid (4mg/mL) as Intradermal Treatments of Melasma.

OBJECTIVE: To compare the efficacy of intradermal platelet-rich-plasma vs. intradermal tranexamic acid in treatment of melasma. STUDY DESIGN: Non-randomised controlled trial. PLACE AND DURATION OF STUDY: Sheikh Zayed Hospital, Rahim Yar Khan from 1st October 2019 to 30th April 2020. METHODOLOGY: Cases of melasma from either gender with age 20-40 years, were included. Diagnosis of melasma was made clinically on the basis of hyperpigmentation at sun-exposed areas and by Wood's lamp.  Severity was labelled on the basis of melasma area and severity index (MASI) score. Cases in group A were managed with 1 ml of intradermal platelet-rich plasma (PRP) and those in group B were offered intradermal tranexamic acid in a dose of 4 mg. The treatment was offered every 4th week and for a total period of 12 weeks; and final outcome was seen at 24th week. At every visit, the cases were noted for their mean MASI score. RESULTS: In this study, there were a total of 64 cases, 32 in each group. There were 19 (59.38%) males in group A and 16 (50%) in group B (p=0.61). Mean age in group A and B was 24.63 ± 9.87 vs. 23.94 ± 8.93 years (p= 0.76). Mean MASI score at baseline was 29.84 ± 5.14 vs. 29.56 ± 4.39, p=0.21. MASI was significantly better in group A at 4 weeks where score was 29.44 ± 5.35 vs. 28.69 ± 4.10, p=0.01. Mean MASI was 12.81 ± 1.78 vs. 18.38 ± 3.50, p=00001 at 12 weeks and 8.72 ± 3.40 vs. 14.97±4.33, p=0.02 at 24 weeks in group A and B, respectively. CONCLUSION: Intradermal PRP is significantly better than intradermal tranexamic acid in management of melasma. Key Words: Melasma, Tranexamic acid, PRP, MASI.

Effect of Elevated Left Ventricular End Diastolic Pressure on Instantaneous Wave-Free Ratio and Fractional Flow Reserve Discordance.

BACKGROUND: Instantaneous wave-free ratio (iFR)-guided physiological assessment has been shown to be non-inferior to fractional flow reserve (FFR)-guided assessment for deciding best treatment strategy for angiographically intermediate stenosis. The diagnostic accuracy of iFR compared to FFR reported in various studies is around 80%. Many factors can lead to iFR/FFR discordance, though underlying physiological mechanism of discordance and its associated factors have not been fully evaluated. The effect of left ventricle end diastolic pressure (LVEDP) on iFR/FFR discordance is unknown and needs further evaluation. METHODS: We performed a single center, non-randomized, both retrospective and prospective study. A total of 65 patients with intermediate coronary stenosis undergoing physiological assessment were included in the study. Patients were assigned to two groups (normal LVEDP and high LVEDP group) based on LVEDP cutoff of 15 mm Hg. iFR and FFR were measured for each patient and iFR/FFR results were compared between the two groups. RESULTS: A significantly large number of patients in elevated LVEDP group had iFR/FFR discordance compared to normal LVEDP group (42.8% vs. 6.7%, P = 0.001). More patients with acute coronary syndrome (ACS) had discordance compared to stale coronary artery disease (CAD) patients (53% vs. 15%, P = 0.003). CONCLUSIONS: Elevated LVEDP can affect iFR and FFR measurements and can lead to discordance. Further studies are required to determine effect of elevated LVEDP on iFR/FFR discordance and whether such discordance is clinically relevant. "Normal range" iFR results should be cautiously interpreted in patients with elevated LVEDP, especially those with ACS.

Optimizing mechanical circulatory support hemodynamics using coronary sinus pacing.

The role of atrioventricular (AV) dyssynchrony as a cause of low Impella device output in cardiogenic shock from acute anterior myocardial infarction (MI) responding to reestablishing AV synchrony has not been previously reported. We present, for the first time, a unique case of AV dyssynchrony causing recurrent hypotension and ventricular fibrillation in such a patient, followed by immediate return to hemodynamic stability after restoring AV synchrony. Our case also highlights the novel use of a Damato multi-polar catheter for coronary sinus pacing to achieve AV synchrony.