Implementing a Pharmacogenomic-driven Algorithm to Guide Antiplatelet Therapy among Caribbean Hispanics: A non-randomized prospective cohort study

Background

After percutaneous coronary intervention (PCI), clopidogrel resistant patients are at an increased risk of major adverse cardiovascular and cerebrovascular events (MACCEs). We aimed to assess whether genotype-guided selection of oral antiplatelet drugs using a clinical decision support (CDS) algorithm reduces the occurrence of these ischemic events and improves outcomes among Caribbean Hispanic patients from Puerto Rico, who are underrepresented in clinical pharmacogenomic (PGx)-guided implementation studies.

Methods

Individual platelet function testing (PRU) measures, CYP2C19*2 and PON1 rs662 genotypes, clinical and demographic data from 8 medical facilities were included. Patients were separated into standard of care (SoC) and genotype-guided groups (150 each). Risk scores were calculated based on a previously developed CDS risk prediction algorithm designed to make actionable treatment recommendations for each patient. Alternative therapy with ticagrelor was recommended for patients with a high risk score ≥2. Statistical associations between patient time free of MACCEs and predictor variables (i.e., treatment groups, risk scores) were tested in this population using Kaplan-Meier survival analyses and Cox proportional-hazards regression models.

Results

Median age of participants is 67 years; BMI: 27.8; 48% women; 14% smokers; 59% with type-2 diabetes mellitus (T2DM). Among patients with high-risk scores who were free from MACCE events 6 months after coronary stenting, genotype-driven guidance of antiplatelet therapy showed superiority over SoC in terms of reducing the incidence rate of atherothrombotic events.

Conclusions

The clinical utility of our PGx-driven CDS algorithm to reduce the incidence rate of MACCEs among post-PCI Caribbean Hispanic patients on clopidogrel was externally demonstrated.

Clinical Trial Registration Unique Identifier

NCT03419325.

Discovery of Ancestry-specific Variants Associated with Clopidogrel Response among Caribbean Hispanics

Background

High on-treatment platelet reactivity (HTPR) with clopidogrel is predictive of ischemic events in adults with coronary artery disease. Despite strong data suggesting HTPR varies with ethnicity, including clinical and genetic variables, no genome-wide association study (GWAS) of clopidogrel response has been performed among Caribbean Hispanics. This study aimed to identify genetic predictors of HTPR in a cohort of Caribbean Hispanic cardiovascular patients from Puerto Rico.

Methods

Local Ancestry inference (LAI) and traditional GWASs were performed on a cohort of 511 clopidogrel-treated patients, stratified based on their P2Y12 reaction units (PRU) into responders and non-responders (HTPR).

Results

The LAI GWAS identified variants within the CYP2C19 region associated with HTPR, predominantly driven by individuals of European ancestry and absent in those with native ancestry. Incorporating local ancestry adjustment notably enhanced our ability to detect associations. While no loci reached traditional GWAS significance, three variants showed suggestive significance at chromosomes 3, 14 and 22 (OSBPL10 rs1376606, DERL3 rs5030613, and RGS6 rs9323567). In addition, a variant in the UNC5C gene on chromosome 4 was associated with an increased risk of HTPR. These findings were not identified in other cohorts, highlighting the unique genetic landscape of Caribbean Hispanics.

Conclusion

This is the first GWAS of clopidogrel response in Hispanics, confirming the relevance of the CYP2C19 cluster, particularly among those with European ancestry, and also identifying novel markers in a diverse patient population. Further studies are warranted to replicate our findings in other diverse cohorts and meta-analyses.

Outcomes of chronic total occlusion percutaneous coronary intervention in patients with prior coronary artery bypass graft surgery: Insights from the LATAM CTO registry

OBJECTIVES

To evaluate the outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI) in patients with and without prior coronary artery bypass graft (CABG) surgery.

BACKGROUND

Data on the outcomes of CTO PCI in patients with versus without CABG remains limited and with scarce representation from developing regions like Latin America.

METHODS

We evaluated patients undergoing CTO PCI in 42 centers participating in the LATAM CTO registry between 2008 and 2020. Statistical analyses were stratified according to CABG status. The outcomes of interest were technical and procedural success and in-hospital major adverse cardiac and cerebrovascular events (MACCE).

RESULTS

A total of 1662 patients were included (n = 1411 [84.9%] no-CABG and n = 251 [15.1%] prior-CABG). Compared with no-CABG, those with prior-CABG were older (67 ± 11 vs. 64 ± 11 years; p < 0.001), had more comorbidities and lower left ventricular ejection fraction (52.8 ± 12.8% vs. 54.4 ± 11.7%; p = 0.042). Anatomic complexity was higher in the prior-CABG group (J-CTO score 2.46 ± 1.19 vs. 2.10 ± 1.22; p < 0.001; PROGRESS CTO score 1.28 ± 0.89 vs. 0.91 ± 0.85; p < 0.001). Absence of CABG was associated with lower risk of technical and procedural failure (OR: 0.60, 95% CI: 0.43-0.85 and OR: 0.58, 95% CI: 0.40-0.83, respectively). No significant differences in the incidence of in-hospital MACCE (3.8% no-CABG vs. 4.4% prior-CABG; p = 0.766) were observed between groups.

CONCLUSION

In a contemporary multicenter CTO-PCI registry from Latin America, prior-CABG patients had more comorbidities, higher anatomical complexity, lower success, and similar in-hospital adverse event rates compared with no-CABG patients.

Pharmacogenomic polygenic risk score for clopidogrel responsiveness among Caribbean Hispanics: A candidate gene approach

This multicenter clinical study was aimed at conducting a targeted pharmacogenomic association analysis of residual on‐clopidogrel platelet reactivity in 474 Caribbean Hispanic patients. Platelet reactivity was measured using the VerifyNow P2Y12 assay and clopidogrel resistance was defined as P2Y12 reaction units (PRUs) greater than or equal to 208. Genotyping was performed using the whole‐genome Infinium MEGA BeadChip array. An ancestry‐adjusted, weighted polygenic risk score (wPGxRS) was developed to account for the effect of multiple variants on PRU and compared between clopidogrel responders and nonresponders. The mean PRU across the study cohort was 173.8 ± 68.5 and 33.5% of patients were defined as clopidogrel resistant. Multivariate linear regression showed that 19% of PRU variability was attributed to nine independent predictors, with CYP2C19*2 (rs4244285) accounting for ~ 7% of observed PRU variation (p < 0.001). PON1 rs662, ABCB1/MDR1 rs2032582, PEAR1 rs12041331 carrier status, and the interaction between African ancestry and rs12041331 carriers also predicted PRU among the participants (p ≤ 0.05). A clear gene‐dose effect was detected between PRU and CYP2C19*2 genotype, consistent with previous studies in European patient populations, as well as rs12777823. Importantly, a significant positive correlation was detected between our novel wPGxRS (4 variants) and PRU among the Hispanic patient population (r_p = 0.35, p < 0.001). Moreover, the wPGxRS discriminated between nonresponders and responders (p = 0.003), indicating that this multigene‐based score is a useful predictor of clopidogrel resistance among Caribbean Hispanics. Taken together, these results help close the gap of knowledge on clopidogrel pharmacogenomics and its potential clinical implementation in this under‐represented population.

Machine-Learning-Based In-Hospital Mortality Prediction for Transcatheter Mitral Valve Repair in the United States

BACKGROUND

Transcatheter mitral valve repair (TMVR) utilization has increased significantly in the United States over the last years. Yet, a risk-prediction tool for adverse events has not been developed. We aimed to generate a machine-learning-based algorithm to predict in-hospital mortality after TMVR.

METHODS

Patients who underwent TMVR from 2012 through 2015 were identified using the National Inpatient Sample database. The study population was randomly divided into a training set (n = 636) and a testing set (n = 213). Prediction models for in-hospital mortality were obtained using five supervised machine-learning classifiers.

RESULTS

A total of 849 TMVRs were analyzed in our study. The overall in-hospital mortality was 3.1%. A naïve Bayes (NB) model had the best discrimination for fifteen variables, with an area under the receiver-operating curve (AUC) of 0.83 (95% CI, 0.80-0.87), compared to 0.77 for logistic regression (95% CI, 0.58-0.95), 0.73 for an artificial neural network (95% CI, 0.55-0.91), and 0.67 for both a random forest and a support-vector machine (95% CI, 0.47-0.87). History of coronary artery disease, of chronic kidney disease, and smoking were the three most significant predictors of in-hospital mortality.

CONCLUSIONS

We developed a robust machine-learning-derived model to predict in-hospital mortality in patients undergoing TMVR. This model is promising for decision-making and deserves further clinical validation.

Machine Learning Prediction Models for In-Hospital Mortality After Transcatheter Aortic Valve Replacement

OBJECTIVES

This study sought to develop and compare an array of machine learning methods to predict in-hospital mortality after transcatheter aortic valve replacement (TAVR) in the United States.

BACKGROUND

Existing risk prediction tools for in-hospital complications in patients undergoing TAVR have been designed using statistical modeling approaches and have certain limitations.

METHODS

Patient data were obtained from the National Inpatient Sample database from 2012 to 2015. The data were randomly divided into a development cohort (n = 7,615) and a validation cohort (n = 3,268). Logistic regression, artificial neural network, naive Bayes, and random forest machine learning algorithms were applied to obtain in-hospital mortality prediction models.

RESULTS

A total of 10,883 TAVRs were analyzed in our study. The overall in-hospital mortality was 3.6%. Overall, prediction models' performance measured by area under the curve were good (>0.80). The best model was obtained by logistic regression (area under the curve: 0.92; 95% confidence interval: 0.89 to 0.95). Most obtained models plateaued after introducing 10 variables. Acute kidney injury was the main predictor of in-hospital mortality ranked with the highest mean importance in all the models. The National Inpatient Sample TAVR score showed the best discrimination among available TAVR prediction scores.

CONCLUSIONS

Machine learning methods can generate robust models to predict in-hospital mortality for TAVR. The National Inpatient Sample TAVR score should be considered for prognosis and shared decision making in TAVR patients.

Implementing a pharmacogenetic-driven algorithm to guide dual antiplatelet therapy (DAPT) in Caribbean Hispanics: protocol for a non-randomised clinical trial

INTRODUCTION

Minority populations in the USA are disproportionately affected by cardiovascular conditions. Reduced responsiveness to clopidogrel among carriers of CYP2C19 variants has been reported in patients with either coronary artery disease (CAD) or acute coronary syndrome (ACS) after the percutaneous coronary intervention (PCI). Previous studies have evaluated CYP2C19 genotyping-guided antiplatelet therapy in selected populations; however, this has yet to be tested among Hispanics. Given the paucity of clinical research on CYP2C19 and antiplatelet clinical outcomes in Hispanics, our study will test the safety and efficacy of a genetic-driven treatment algorithm to guide dual antiplatelet therapy (DAPT) in Caribbean Hispanics.

METHODS AND ANALYSIS

This is a multicentre, prospective, non-randomised clinical trial that proposes an assessment of pharmacogenomic-guided DAPT in post-PCI Caribbean Hispanic patients with ACS or CAD. We will recruit 250 patients to be compared with a matched non-concurrent cohort of 250 clopidogrel-treated patients (standard-of-care). Major adverse cardiovascular events (MACEs) such as all-cause death, myocardial infarction (MI), stroke, coronary revascularisation, stent thrombosis and bleedings over 6 months will be the study endpoints. Among the recruited, high-risk patients will be escalated to ticagrelor and low-risk patients will remain on clopidogrel. The primary objective is to determine whether genetic-guided therapy is superior to standard of care. The secondary objective will determine if clopidogrel treatment in low-risk patients is not associated with a higher rate of MACEs compared with escalated antiplatelet therapy in high-risk patients. Patients will be enrolled up to the group's completion.

ETHICS AND DISSEMINATION

Approval was obtained from the Institutional Review Board of the University of Puerto Rico Medical Sciences Campus (protocol # A4070417). The study will be carried out in compliance with the Declaration of Helsinki and International Conference on Harmonization Good Clinical Practice Guidelines. Findings will be published in a peer-reviewed journal and controlled access to experimental data will be available.

TRIAL REGISTRATION NUMBER

NCT03419325; Pre-results.

Increased Risk of Perioperative Ischemic Stroke in Patients Who Undergo Noncardiac Surgery with Preexisting Atrial Septal Defect or Patent Foramen Ovale

OBJECTIVES

To evaluate whether a preoperative diagnosis of atrial septal defect (ASD) or patent foramen ovale (PFO) is associated with perioperative stroke in noncardiac surgery and their outcomes.

DESIGN

Retrospective cohort analysis.

SETTING

United States hospitals.

PARTICIPANTS

Adults patients (≥18 years old) who underwent major noncardiac surgery from 2010 to 2015 were identified using the Healthcare Cost and Utilization Project's National Readmission Database.

INTERVENTIONS

Preoperative diagnosis of ASD or patent foramen ovale.

MEASUREMENTS AND MAIN RESULTS

Among the 19,659,161 hospitalizations for major noncardiac surgery analyzed, 12,248 (0.06%) had a preoperative diagnosis of ASD/PFO. Perioperative ischemic stroke occurred in 723 (5.9%) of patients with ASD/PFO and 373,291 (0.02%) of those without ASD/PFO (adjusted odds ratio [aOR], 16.7; 95% confidence interval [CI]: 13.9-20.0). Amongst the different types of noncardiac surgeries, obstetric, endocrine, and skin and burn surgery were associated with higher risk of stroke in patients with pre-existing ASD/PFO. Moreover, patients with ASD/PFO also had an increased in-hospital mortality (aOR, 4.6, 95% CI: 3.6-6.0), 30-day readmission (aOR, 1.2, 95% CI: 1.04-1.38), and 30-day stroke (aOR, 7.2, 95% CI: 3.1-16.6). After adjusting for atrial fibrillation, ischemic stroke remained significantly high in the ASD/PFO group (aOR: 23.7, 95%CI 19.4-28.9), as well as in-hospital mortality (aOR: 5.6, 95% CI 4.1-7.7), 30-day readmission (aOR: 1.19, 95%CI 1.0-1.4), and 30-day stroke (aOR: 9.3, 95% CI 3.7-23.6).

CONCLUSIONS

Among adult patients undergoing major noncardiac surgery, pre-existing ASD/PFO is associated with increased risk of perioperative ischemic stroke, in-hospital mortality, 30-day stroke, and 30-day readmission after surgery.

Qualitative Assessment of Color M-Mode Signals in the Evaluation of Left Ventricular Diastolic Function: A Proof of Concept Study

OBJECTIVES

Although the most recent American Society of Echocardiography guidelines are a major step forward in echocardiographic evaluation of diastolic function, the ability to differentiate between normal and abnormal function remains challenging. The authors aimed to determine whether qualitative assessments of color M-mode flow displays could be a useful parameter in the evaluation of left ventricular (LV) diastolic dysfunction.

DESIGN

Retrospective observational study.

SETTING

Tertiary care level hospital.

PARTICIPANTS

The study comprised echocardiographic data from 105 consecutive patients.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

Patients were allocated into the following 3 groups according to the LV diastolic function based on current American Society of Echocardiography recommendation guidelines for LV diastolic dysfunction classification: group I-normal function (n = 40); group II-early relaxation abnormalities (grade I) (n = 50), and group III-elevated LV pressures (grade II) (n = 15). Patients with normal diastolic function were younger (45 ± 14 y) than those with diastolic dysfunction (group II: 64 ± 10 y and group III: 56 ± 15 y) (p < 0.05). Volumetric echocardiographic parameters and mitral inflow and mitral annulus tissue Doppler imaging measures were significantly different among the 3 studied groups (p < 0.05). Interestingly, qualitative assessment of color M-mode flows displayed distinctive signals based on the left ventricle filling properties. Intraobserver and interobserver variability to determine the reliability of these signals were robust (weighted kappa 0.84 ± 0.11 and 0.65 ± 0.13, respectively).

CONCLUSION

Qualitative assessment of color M-mode flow displays offers simple and reliable information of potential usefulness in the evaluation of LV diastolic function.

Assessment of Mitral Annular Plane Systolic Excursion in Patients With Left Ventricular Diastolic Dysfunction

Background

Mitral annular plane systolic excursion (MAPSE) is a well-known surrogate measurement of left ventricular ejection fraction (LVEF) and prognostic factor for many cardiac conditions. However, little is known about its role in assessing LV diastolic function; we therefore sought to identify potential determinants of MAPSE in patients with LV diastolic dysfunction (LVDD).

Methods

Our echocardiographic database was queried for studies of patients with normal sinus. Patients were allocated into three groups: LVDD 0, LVDD 1 and LVDD 2 in accordance with LVDD stages recommended by the American Society of Echocardiography guidelines.

Results

A total of 107 echocardiographic studies were included in the study. The mean MAPSE was 1.22 ± 0.32 cm. Groups LVDD 0 (n = 23), LVDD 1 (n = 43), and LVDD 2 (n = 41) were significantly different in most of the studied variables. Particularly, MAPSE differed between the three groups (P < 0.01). A multiple regression analysis showed that age, LVEF and LV mass index were predictors of MAPSE instead of LVDD and left atrial measurements. Finally, a regression model was constructed to predict MAPSE in the studied group showing that age and LVEF explained a 46% of the MAPSE variation. A two-way contour plot was illustrated to ease the model interpretation.

Conclusions

Age and measures of LV systolic function correlated well with MAPSE. A simplified model to predict MAPSE based on age and LVEF is proposed. Additional studies are needed to examine the potential role of MAPSE in identifying symptoms and overall prognosis in LVDD patients.

Racial/Ethnic Disparities in Patients Undergoing Transcatheter Aortic Valve Replacement: Insights from the Healthcare Cost and Utilization Project's National Inpatient Sample

PURPOSE

To identify racial/ethnic disparities in utilization rates, in-hospital outcomes and health care resource use among Non-Hispanic Whites (NHW), African Americans (AA) and Hispanics undergoing transcatheter aortic valve replacement (TAVR) in the United States (US).

METHODS AND RESULTS

The National Inpatient Sample database was queried for patients ≥18 years of age who underwent TAVR from 2012 to 2014. The primary outcome was all-cause in hospital mortality. A total of 36,270 individuals were included in the study. The number of TAVR performed per million population increased in all study groups over the three years [38.8 to 103.8 (NHW); 9.1 to 26.4 (AA) and 9.4 to 18.2 (Hispanics)]. The overall in-hospital mortality was 4.2% for the entire cohort. Race/ethnicity showed no association with in-hospital mortality (P > .05). Though no significant difference were found between AA and NHW in any secondary outcome, being Hispanic was associated with higher incidence of acute myocardial infarction (aOR = 2.02; 95% CI, 1.06-3.85; P = .03), stroke/transient ischemic attack (aOR = 1.81; 95% CI, 1.04-3.14; P = .04), acute kidney injury (aOR = 1.65; 95% CI, 1.23-2.21; P < .01), prolonged length of stay (aOR = 1.18; 95% CI, 1.08-1.29; P < .01) and higher hospital costs (aOR = 1.27; 95% CI, 1.18-1.36; P < .01).

CONCLUSION

There are significant racial disparities in patients undergoing TAVR in the US. Though in-hospital mortality was not associated with race/ethnicity, Hispanic patients had less TAVR utilization, higher in-hospital complications, prolonged length of stay and increased hospital costs.

Dynamic Piston Function of the Mitral Annulus to Assess Early Left Ventricular Diastolic Filling: A Proof of Concept Study

INTRODUCTION

Early left ventricular (LV) filling has been described as an asymmetric toroidal vortex ring of blood entering the LV upon opening of the mitral valve. This phenomenon is in part responsible for cyclical changes in LV volumes during the cardiac cycle and also contributes to the apical and basal longitudinal displacements of the mitral annulus (MA). Although MA early diastolic (e') velocities have been used to assess early LV filling characteristics, accurate distinction between normal aging and pathological diastolic dysfunction (DD) might be challenging at times.

METHODS

In this pilot study, echocardiographic data from 60 consecutive patients were reviewed. The studied population was allocated into three groups based on the new American Society of Echocardiography guidelines for diastolic dysfunction classification. To better define LVDD, we based our interpretation of MA tissue Doppler imaging (TDI) signals on the well-described displacement pump mechanism of the MA plane functioning as a piston unit.

RESULTS

Patients with normal diastolic function were younger (50 ± 14 years) than those with DD (group II: 69 ± 8 and group III: 63 ± 17 years) (p < 0.001) with a slight female predominance (57%). As expected, volumetric variables as well as mitral inflow and MA TDI measures were significantly different among the three studied groups (p < 0.001) with the exception of the left atrial volume index. Interestingly, careful interrogation of the MA TDI signal revealed a distinctive appearance of a recoil signal right after the MA e' velocity only occurring in patients with normal LV diastolic function.

CONCLUSIONS

Identification of an early characteristic recoil signal occurring on the MA TDI right after the e' velocity seems to be useful in the characterization of LVDD. Additional prospective studies are now needed to validate its utility as an additional criterion to be used in LVDD.

Prevalence of pharmacogenomic variants affecting the efficacy of clopidogrel therapy in the Hispanic Community Health Study/Study of Latinos cohort

PURPOSE

Although clopidogrel is the most widely used oral P2Y12 receptor antagonist, up to 10% of acute coronary syndrome patients treated with clopidogrel will experience a recurrent myocardial infarction and 2-3% will experience stent thrombosis within 1 year. The purpose of this research is to describe the prevalence of pharmacogene variants associated with clopidogrel responsiveness (CYP2C19, B4GALT2, ABCB1, PON1, CES1 and P2RY12) in Hispanic/Latino patients of diverse backgrounds.

METHODS

Minor allele frequencies of nine variants from participants of Hispanic Community Health Study/Study of Latinos were compared between subpopulations as well as to continental ancestry references using z-test for independent proportions.

RESULTS

MAFs for six out of nine variants differed between Caribbean and Mainland subpopulations (p < 0.05). Compared with European reference group, MAFs of ABCB1, CES1 and PON1 were higher in Hispanic Community Health Study/Study of Latinos, whereas B4GALT2 and CYP2C19*2 and *17 were lower.

CONCLUSION

Significant differences in the prevalence of most pharmacogenomic variants related to clopidogrel response provide a foundation to better inform ongoing and future clinical studies of clopidogrel pharmacogenetics in the US Hispanic/Latino populations.

Bivalirudin versus heparin in patients undergoing percutaneous peripheral interventions: A systematic review and meta-analysis

Background

Bivalirudin may be an effective alternative anticoagulant to heparin for use in percutaneous peripheral interventions. We aimed to compare the safety and efficacy of bivalirudin versus heparin as the procedural anticoagulant agent in patients undergoing percutaneous peripheral intervention.

Methods

For this meta-analysis and systematic review, we conducted a search in PubMed, Medline, Embase, and Cochrane for all the clinical studies in which bivalirudin was compared to heparin as the procedural anticoagulant in percutaneous peripheral interventions. Outcomes studied included all-cause mortality, all-bleeding, major and minor bleeding, and access site complications.

Results

Eleven studies were included in the analysis, totaling 20,137 patients. There was a significant difference favoring bivalirudin over heparin for all-cause mortality (risk ratio 0.58, 95% CI 0.39–0.87), all-bleeding (risk ratio 0.62, 95% CI 0.50–0.78), major bleeding (risk ratio 0.61, 95% CI 0.39–0.96), minor bleeding (risk ratio 0.66, 95% CI 0.47–0.92), and access site complications (risk ratio 0.66, 95% CI 0.51–0.84). There was no significant difference in peri-procedural need for blood transfusions (risk ratio 0.79, 95% CI 0.57–1.08), myocardial infarction (risk ratio 0.87, 95% CI 0.59–1.28), stroke (risk ratio 0.77, 95% CI 0.59–1.01), intracranial bleeding (risk ratio 0.77, 95% CI 0.29–2.02), or amputations (OR 0.75, 95% CI 0.53–1.05).

Conclusion

Our meta-analysis suggests that bivalirudin use for percutaneous peripheral interventions is associated with lower all-cause mortality, bleeding, and access site complications as compared to heparin. Further large randomized trials are needed to confirm the current results.

Pharmacogenetic association study on clopidogrel response in Puerto Rican Hispanics with cardiovascular disease: a novel characterization of a Caribbean population

Introduction

High on-treatment platelet reactivity (HTPR) to clopidogrel imparts an increased risk for ischemic events in adults with coronary artery disease. Platelet reactivity varies with ethnicity and is influenced by both clinical and genetic variables; however, no clopidogrel pharmacogenetic studies with Puerto Rican patients have been reported. Therefore, we sought to identify clinical and genetic determinants of on-treatment platelet reactivity in a cohort of Puerto Rican patients with cardiovascular disease.

Methods

We performed a retrospective study of 111 patients on 75 mg/day maintenance dose of clopidogrel. Patients were allocated into 2 groups: Group I, without HTPR; and Group II, with HTPR. Platelet function was measured ex vivo using the VerifyNow® P2Y12 assay and HTPR was defined as P2Y12 reaction units (PRU) ≥230. Genotyping testing was performed using Taqman^® Genotyping Assays.

Results

The mean PRU across the cohort was 203±61 PRU (range 8–324), and 42 (38%) patients had HTPR. Multiple logistic regression showed that 27% of the total variation in PRU was explained by a history of diabetes mellitus, hematocrit, CYP2C19*2, and PON1 p.Q192R. Body mass index (odds ratio [OR]=1.15; 95% CI: 1.03–1.27), diabetes mellitus (OR=3.46; 95% CI: 1.05–11.43), hematocrit (OR=0.75; 95% CI: 0.65–0.87), and CYP2C19*2 (OR=4.44; 95% CI: 1.21–16.20) were the only independent predictors of HTPR.

Conclusion

Moreover, we propose a predictive model to determine PRU values as measured by VerifyNow P2Y12 assay for the Puerto Rican Hispanic population. This model has the potential to identify Hispanic patients at higher risk for adverse events on clopidogrel.

Clinical Relevant Polymorphisms Affecting Clopidogrel Pharmacokinetics and Pharmacodynamics: Insights from the Puerto Rico Newborn Screening Program

Background: Variations in several clopidogrel-pharmacogenes have been linked to clopidogrel response variability and clinical outcomes. We aimed to determine the frequency distribution of major polymorphisms on CYP2C19, PON1, ABCB1 and P2RY12 pharmacogenes in Puerto Ricans. Methods: This was a cross-sectional, population-based study of 200 unrelated "Guthrie" cards specimens from newborns registered in the Puerto Rican newborn screening program (PRNSP) between 2004 and 2014. Taqman® SNP assay techniques were used for genotyping. Results: Minor allele frequencies (MAF) were 46% for PON1 (rs662), 41% for ABCB1 (rs1045642), 14% for CYP2C19*17, 13% for CYP2C19*2, 12% for P2RY12-H2 and 0.3% for CYP2C19*4. No carriers of the CYP2C19*3 variants were detected. All alleles and genotype proportions were found to be in Hardy⁻Weinberg equilibrium (HWE). Overall, there were no significant differences between MAFs of these variants in Puerto Ricans and the general population (n = 453) of the 1000 Genome project, except when comparisons to each individual parental group were performed (i.e., Africans, Europeans and East-Asians; p < 0.05). As expected, the prevalence of these markers in Puerto Ricans most resembled those in the 181 subjects from reference populations of the Americas. Conclusions: These prevalence data provide a necessary groundwork for future clinical studies of clopidogrel pharmacogenetics in Caribbean Hispanics.

Nonbacterial Thrombotic Endocarditis of the Tricuspid Valve in a Male Patient with Antiphospholipid Syndrome

Valve vegetations in nonbacterial thrombotic endocarditis consist of fibrin and platelet aggregates and can be related to circulating immune complexes, such as in the case of antiphospholipid syndrome. In patients with primary antiphospholipid syndrome, echocardiographic studies have disclosed heart valve abnormalities in about a third of patients. Unusual associations between antiphospholipid syndrome and nonbacterial thrombotic endocarditis include presentation as an intracardiac mass compatible with a myxoma on imaging studies, as well as isolated involvement of the tricuspid valve. Both of these scenarios have been previously reported in female patients. This article presents the case of a 53-year-old Hispanic male with antiphospholipid syndrome who presented to the hospital with symptoms of heart failure and persistent right calf pain. An intracardiac mass attached to the anterior leaflet of the tricuspid valve was found through transthoracic echocardiography. Further imaging studies suggested the mass to be a myxoma and the patient underwent mass excision with tricuspid valve replacement. Pathology report of the surgical specimen was consistent with a diagnosis of nonbacterial thrombotic endocarditis. This case highlights the importance of considering nonbacterial thrombotic endocarditis as a key differential diagnosis in patients with concomitant antiphospholipid syndrome and intracardiac masses, as well as challenges encountered in diagnosis and management.

Potential Usefulness of Clopidogrel Pharmacogenetics in Cerebral Endovascular Procedures and Carotid Artery Stenting

BACKGROUND

Previous reports have shown inadequate response to dual antiplatelet therapy (DAPT) with aspirin and clopidogrel in 5-30% of patients undergoing percutaneous coronary interventions (PCI), due mostly to clopidogrel resistance. This prevalence increases up to 66% in patients undergoing neurointerventional procedures. However, clinical significance of CYP2C19 genotypes in neurointerventional procedures or carotid artery stenting (CAS) is unknown.

OBJECTIVE

The purpose of this review is to update our current knowledge and understanding of the pharmacogenetic basis for poor clopidogrel responsiveness in patients undergoing CAS and endovascular interventions as well as to explore usefulness of genotyping to reduce the rate of procedure-related thrombosis that results in ischemic complications.

METHOD

A literature search for pharmacogenetic studies in cerebral endovascular interventions and CAS was conducted on three databases using a list of the most relevant pharmacogenetic biomarkers.

RESULTS

The review included 7 papers involving 3 genetic polymorphisms on CYP2C19 and 442 subjects. Patients harboring at least one loss-of-function CYP2C19 polymorphism (e.g., CYP2C19*2 and *3) are at an increased risk of thromboembolic complications such as stent thrombosis following neurointerventional procedures. Notably, patients who carry the gain-of-function CYP2C19*17 allele may have increased risk of ischemic events following endovascular treatment, independent of clopidogrel responsiveness.

CONCLUSION

Studies assessing the influence of CYP2C19 polymorphisms on high on-treatment platelet reactivity in CAS and cerebrovascular disease patients are still limited and need further validation in large multicenter studies. This review covers an important topic in the field of antiplatelet therapy for cerebral endovascular procedures and CAS.

Effect of cilostazol on platelet reactivity among patients with peripheral artery disease on clopidogrel therapy

BACKGROUND

Antiplatelet therapy with clopidogrel is recommended to reduce cardiovascular events in patients with peripheral artery disease (PAD); however, clopidogrel efficacy has not been adequately studied in this patient population. Therefore, we aimed to determine the effects of cilostazol therapy on platelet reactivity among PAD patients on clopidogrel.

METHODS

We performed a cross-sectional pilot study of 46 Puerto Rican patients diagnosed with PAD. The cohort was divided based on use of clopidogrel and cilostazol (n=24) or clopidogrel alone (n=22). Platelet function was measured ex vivo using the VerifyNow P2Y12 assay. Genomic DNA was extracted from peripheral blood samples using the QIAamp DNA Blood Midi Kit, which was subjected to candidate variant genotyping (CYP2C19, ABCB1, PON1 and P2RY12) using TaqMan quantitative polymerase chain reaction assays. All analyses were performed using SAS version 9.4 (SAS Institute).

RESULTS

Among all enrolled patients, 18 (39%) had high on-treatment platelet reactivity (HTPR). The mean platelet reactivity was 207±53 (range, 78-325) with higher P2Y12 reaction units in the non-cilostazol group, 224±45 vs. 191±55 on the cilostazol group (p=0.03). No significant differences were observed in the clinical or genetic variables between the two groups. A multiple regression analysis determined that history of diabetes mellitus (p=0.03), use of cilostazol (p=0.03) and hematocrit (p=0.02) were independent predictors of platelet reactivity.

CONCLUSIONS

In Puerto Rican PAD patients on clopidogrel therapy, history of diabetes mellitus, use of cilostazol and hematocrit are independent predictors of platelet reactivity. Adjunctive cilostazol therapy may enhance clopidogrel efficacy among PAD patients with HTPR.

Are Measures of Left Ventricular Longitudinal Shortening Affected by Left Atrial Enlargement?

BACKGROUND

Even though left atrial (LA) size and function are intimately related to left ventricular (LV) diastolic dysfunction, the role of LA with regard to LV systolic function is less clear. Consequently, we examined the potential association that might exist between measures of longitudinal LV systolic shortening and LA dilation using LA volume index (LAVI).

METHODS

In this retrospective analysis, data from 75 echocardiograms (mean age 53 ± 14; range 24 - 89 years; mean body surface area (BSA) 2.0 ± 0.3) were analyzed.

RESULTS

Peak global longitudinal (PGLS) correlated best with LV mass index (LVMI) followed by mitral annular systolic excursion (MAPSE), and age. Similar results were obtained when analyzing the best variables that correlated with LAVI. Finally, MAPSE correlated best with PGLS, then with MA tissue Doppler systolic velocity, BSA, and LAVI in that order. All patients had normal LV ejection fraction (LVEF) and normal sinus rhythm when studied.

CONCLUSIONS

LAVI does not directly affect LV systolic function and longitudinal measures of LV shortening are mainly dependent on LV mass. Additional studies are now required to determine how these associations vary when different degrees of LV dilatation and systolic dysfunction are included in the analysis.

A Reminder From the Devastation Hurricane Maria Left Behind

On September 20, 2017, Hurricane Maria hit Puerto Rico, causing an unprecedented humanitarian crisis on a level that none of us have experienced before. The following editorial intends to show a physician's perspective of the impact of this storm on healthcare, particularly in triggering cardiovascular events.

Mitral Annular Dynamics and Left Ventricular Diastole

Background

Though diastolic interrogation of the mitral annulus (MA) using tissue Doppler imaging (TDI) has been quite useful in assessing left ventricular (LV) diastolic function, the relative contribution of the previous cycle MA systolic displacement or velocity components to subsequent LV diastole has not been previously investigated. We therefore sought to determine the association between MA systolic dynamics and LV diastolic function parameters.

Methods

For this retrospective study, only complete echocardiograms having good endocardial border resolution of both left atrial (LA) and LV chambers with M-mode (MAPSE) and tissue Doppler of the lateral MA (MA TDI S’) as well as complete Doppler data to perform assessment of LV diastole were included in our analysis.

Results

Data from 100 patients (mean age 54 ± 14) showed that both MA systolic displacement and velocity correlate with LV ejection fraction (P < 0.05). Only MA displacement was associated with age and LV mass. Most importantly no correlation was found between MAPSE and LV diastole. However, in sharp contrast MA TDI S’ correlated with MA relaxation velocities during both early and late LV diastole.

Conclusion

Even though MAPSE and MA TDI S’ are surrogate measures of LV ejection fraction, only MA TDI S’ correlates with diastolic MA velocities as no correlation was identified between MAPSE and measures of LV diastole. Additional studies are now warranted to explore whether a reduced MA TDI S’ may affect the symptomatic profile or the overall prognosis of patients with LV diastolic dysfunction.

Clinical determinants of clopidogrel responsiveness in a heterogeneous cohort of Puerto Rican Hispanics

BACKGROUND

Clopidogrel is by far the most prescribed platelet adenosine diphosphate (ADP) antagonist in Puerto Rico despite the advent of newer agents (prasugrel and ticagrelor). Given the paucity of data on clopidogrel responsiveness in Hispanics, we sought to determine the association between clinical characteristics and platelet reactivity in Puerto Rican patients on clopidogrel therapy.

STUDY POPULATION

A total of 100 Puerto Rican patients on clopidogrel therapy were enrolled and allocated into two groups: Group I, without high on-treatment platelet reactivity (HTPR); and Group II, with HTPR. Platelet function was measured ex vivo using the VerifyNow® P2Y12 assay.

RESULTS

The cohort was comprised of Hispanic patients with coronary artery disease (57%), peripheral artery disease (32%), carotid artery stenosis (7%), cerebral artery aneurysm (2%), and stroke (2%). Mean platelet reactivity was 200 ± 61 P2Y12 reaction units (PRUs) (range: 8-324), and 35% of patients had HTPR (PRUs ⩾ 230). Multivariable logistic regression analysis determined that diabetes mellitus (DM) [odds ratio (OR) = 3.27; 95% confidence interval (CI): 1.20-8.96], use of proton-pump inhibitors (PPIs) (OR = 3.60; 95% CI: 1.09-11.82), and calcium channel blockers (CCBs) (OR = 3.10; 95% CI: 1.09-8.83) were independent predictors of HTPR ( p < 0.05) after adjusting for other clinical variables.

CONCLUSIONS

In a sample of 100 Puerto Rican Hispanic patients on clopidogrel, 35% had HTPR. Furthermore, DM, PPIs and CCBs predicted HTPR. Clinical outcome data are needed to identify appropriate PRU thresholds for risk prediction in the Puerto Rican population.

Left Ventricular Velocity of Propagation: A Useful Non-Invasive Measurement When Assessing Hemodynamic Alterations in Pulmonary Arterial Hypertension

Background

Left ventricular (LV) velocity of propagation (Vp) has been shown to be inversely related to the LV relaxation time constant. We sought to examine Vp from a group of chronic pulmonary hypertension (cPH) patients and compare these values to Vp obtained in normal individuals and patients with known LV diastolic dysfunction (LVDD).

Methods

Echo-Doppler data and Vp measurements were retrospectively collected from all patients. The studied population was divided into four groups. Group I comprised of 15 patients with normal LV diastole, group II included 27 patients with stage 1 LVDD, group III was made up of 27 patients with stage 2 LVDD, and group IV included 66 patients with cPH.

Results

In the cPH population studied, patients had smaller end-diastolic LV cavities with the highest Vp values but their early mitral inflow to Vp ratios were not different from healthy controls. In addition, Vp values and pulmonary wedge capillary pressures were significantly associated in patients with LV dysfunction or pulmonary hypertension (P < 0.01).

Conclusions

LVVp might be a useful non-invasive measurement to be routinely obtained in cPH patients as it probably not only reflects the compressive forces being exerted on the LV, known to increase Vp, but also might be quite useful for the non-invasive assessment of pulmonary capillary wedge pressures in these patients.

Epidemiological Profile of Hispanics Admitted With Acute Myocardial Infarction in Puerto Rico: The Experience of 2007, 2009 and 2011

BACKGROUND

A limited number of studies have been published about coronary artery disease in Hispanics, particularly among the Puerto Rican population. The aim of this study was to present a clinical epidemiological profile and management practices in patients hospitalized in Puerto Rico with acute myocardial infarction (AMI).

METHODS

This secondary data analysis from the Puerto Rico Cardiovascular Surveillance Study included 6,162 patients at 19 hospitals in Puerto Rico, during years 2007, 2009 and 2011.

RESULTS

The mean age of the patients diagnosed with AMI was 67 ± 13.6 years old, with women being older than men (P < 0.001). Women had a different risk factor burden when compared to men. Car/walked in was the principal mode of hospital transportation (65.9%). Women received less medications and cardiac procedures when compared to men. While no significant differences in length of hospital stay (LOS) were observed between genders, in-hospital mortality rate was higher in females when compared with males (6.5% vs. 4.5%; P < 0.001).

CONCLUSION

Prompt initiatives should be implemented to raise awareness, reduce gender disparities and improve outcomes in patients hospitalized with an AMI in Puerto Rico.

Maximal systolic excursion of the tricuspid annulus is independent of right atrial size and function in chronic pulmonary hypertension

BACKGROUND

Even though the tricuspid annulus (TA) is anatomically and functionally related to right atrioventricular dependence and tricuspid annular plane systolic excursion (TAPSE) is a well-known measure of right ventricular (RV) systolic function, there is paucity of data regarding the potential impact that right atrial (RA) size and function have on TAPSE. Hence, we sought to determine whether RA volumetric and longitudinal measures affect TAPSE in patients with chronic pulmonary hypertension (cPH).

METHODS

In this retrospective study, echocardiographic data from 110 patients were reviewed and the studied population was divided into Group I consisting of 50 patients (50±11 years) without PH and Group II that included 60 patients (55±14 years) with cPH.

RESULTS

Even though RA areas, RA fractional area change, and maximal long-axis length measurements were abnormal in cPH patients, TA tissue Doppler imaging systolic velocity and RV fractional area change were the only useful variables in identifying patients with abnormal TAPSE (P<.0001 and P=.018, respectively). Additionally, TAPSE was independent of all RA measures, left ventricular ejection fraction, and age (P>.05).

CONCLUSIONS

Based on these results, TAPSE does not appear to be influenced by either RA size or function. Additional studies using strain echocardiography to interrogate RA mechanics might now be very useful to advance our understanding of TA motion in cPH patients given recent data showing that RA function accounts for a significantly greater proportion of total right heart function in patients with cPH than in normal subjects.

Linking Chronic Inflammation with Cardiovascular Disease: From Normal Aging to the Metabolic Syndrome

The metabolic syndrome (MetS) is a cluster of clinical disorders including an unhealthy body habitus with a large waistline, dyslipidemia, glucose intolerance and hypertension. It is known that these disorders not only increase the chances of developing type 2 diabetes mellitus (T2DM), but also cardiovascular disease (CVD). Furthermore, the co-occurrence of all these risk factors known as the MetS is linked to pathways sharing common underlying mediators and mechanisms. Though insulin resistance has been considered as the root of the problem to explain the conglomerate of metabolic abnormalities within this syndrome; new evidence points to several pro-inflammatory cytokines, reactive oxygen species and free fatty acid intermediates might play an even greater role in regulating a series of intracellular signaling pathways sustain as well as perpetuate the development of the MetS and its CVD complications. Since having a diagnosis of MetS confers not only a 5-fold increase in the risk of T2DM, but also a 2-fold risk of developing CVD over a period of 5 to 10 years; it is vital to better recognize the mechanisms by which the MetS is associated with such adverse outcomes. Therefore, it is the purpose of this review to address (1) how inflammation modifies insulin sensitivity, (2) known factors believed to contribute to this process, and (3) new concepts of inflammatory markers in regulating the development of MetS and its individual components.

Strain Imaging Echocardiography: What Imaging Cardiologists Should Know

Despite recent advances in clinical imaging, echocardiography remains as the most accessi-ble and reliable noninvasive. Since knowledge of left ventricular systolic function remains so critically important in determining prognosis; every effort should be made to prevent subjective estimations. The advent of strain imaging echocardiography now offers a readily available and portable imaging tool that not only offers an objective characterization of myocardial dynamics; but also allows for early detection of subclinical left ventricular dysfunction. This review outlines the basic concepts of strain imaging to better understand the mechanism of myocardial function as well their applicability in the least common cardiac diagnosis among current clinical practice.

Left Ventricular Diastolic Function Assessment of a Heterogeneous Cohort of Pulmonary Arterial Hypertension Patients

BACKGROUND

Pulmonary arterial hypertension (PAH) is known to trigger right ventricular (RV) remodeling that might compromise left ventricular (LV) filling due to inter-ventricular interdependence. In this study, we aimed to examine standard echocardiographic measurements of LV diastolic function in PAH patients.

METHODS

In this retrospective study, we identified clinical as well as complete echocardiographic data from 128 chronic PAH patients to fully assess LV diastolic dysfunction (LVDD) using standard recommended Doppler guidelines. Accordingly, patients were divided into three groups: LVDD 0, LVDD 1 and LVDD 2.

RESULTS

The mean age of the studied population was 57 ± 14 years with a mean pulmonary artery systolic pressure (PASP) of 55 ± 21 mm Hg. A total of 36% of the study patients had normal LV diastolic function. However, 64% had LVDD with LVDD stage 1 being the most common (48%). In terms of echocardiographic data, significant differences were found among the three LVDD groups in regards to PASP, LV end systolic and diastolic volumes, tricuspid annular plane systolic excursion, right ventricular fractional area change as well as many other tissue Doppler imaging parameters. Finally, just age and PASP were predictors of abnormal LV diastolic function (P < 0.05).

CONCLUSIONS

Impaired relaxation is a common abnormality in PAH patients. Additional studies are warranted to determine whether LVDD alters prognosis or is related to changes in the symptomatic profile of this group of patients.

Potential usefulness of diastolic parameters measured by strain imaging echocardiography in the early prediction of chemotherapy-induced cardiotoxicity

Over the past decades, chemotherapy has significantly increased the overall prognosis and survival of several patients diagnosed with cancer. However, the usefulness of some chemotherapeutic agents has been hindered by a collateral dose-dependent cardiotoxicity. To date, although extensive efforts have been directed to the early detection of subclinical toxicity in patients treated with these drugs, it remains unclear which approach would be best in order to prevent chemotherapy-induced cardiotoxicity (CIC). For many years, conventional echocardiography has been among preferred noninvasive imaging modality to monitor left ventricular ejection fraction (LVEF) in patients undergoing chemotherapy. Unfortunately, a significant reduction in LVEF is not recognized early on after chemotherapy-induced myocardial damage. Moreover, delayed recognition has been associated with poor recovery potential and poor clinical outcome. Thus, there is a critical need to identify early, reliable parameters of subclinical injury. Myocardial deformation imaging, also known as strain imaging echocardiography (SIE), is becoming readily available for advanced routine echocardiography and has shown value in detecting subclinical ventricular dysfunction in several clinical scenarios. Abnormalities in systolic deformation parameters have been identified as early manifestation but left ventricular diastolic properties remain less well defined. We hypothesize that onset as well as progression of cardiotoxicity not only should disturb deformation curves of myocardial contraction, but also relaxation. Hence, SIE may detect subtle myocardial changes in diastole that could be of potential benefit in the early prediction of CIC. If this premise is proven correct, the use of a standardized advanced echocardiographic imaging protocol using both, systolic and diastolic strain imaging, will prove to be a powerful noninvasive tool as baseline and follow-up of these patients. Furthermore, it will foster the developing of more effective screening strategies in at risk cancer survivor populations, or identify the best time to start cardioprotective therapy to prevent CIC. Also, this experience might be extrapolated to other non-oncologic patient population in need of a surveillance tool to early recognize cardiac injury secondary to the use of cardiotoxic medications.

Potential of a Pharmacogenetic-Guided Algorithm to Predict Optimal Warfarin Dosing in a High-Risk Hispanic Patient: Role of a Novel NQO1*2 Polymorphism

Deep abdominal vein thrombosis is extremely rare among thrombotic events secondary to the use of contraceptives. A case to illustrate the clinical utility of ethno-specific pharmacogenetic testing in warfarin management of a Hispanic patient is reported. A 37-year-old Hispanic Puerto Rican, non-gravid female with past medical history of abnormal uterine bleeding on hormonal contraceptive therapy was evaluated for abdominal pain. Physical exam was remarkable for unspecific diffuse abdominal tenderness, and general initial laboratory results-including coagulation parameters-were unremarkable. A contrast-enhanced computed tomography showed a massive thrombosis of the main portal, splenic, and superior mesenteric veins. On admission the patient was started on oral anticoagulation therapy with warfarin at 5 mg/day and low-molecular-weight heparin. The prediction of an effective warfarin dose of 7.5 mg/day, estimated by using a recently developed pharmacogenetic-guided algorithm for Caribbean Hispanics, coincided with the actual patient's warfarin dose to reach the international normalized ratio target. We speculate that the slow rise in patient's international normalized ratio observed on the initiation of warfarin therapy, the resulting high risk for thromboembolic events, and the required warfarin dose of 7.5 mg/day are attributable in some part to the presence of the NQO1*2 (g.559C>T, p.P187S) polymorphism, which seems to be significantly associated with resistance to warfarin in Hispanics. By adding genotyping results of this novel variant, the predictive model can inform clinicians better about the optimal warfarin dose in Caribbean Hispanics. The results highlight the potential for pharmacogenetic testing of warfarin to improve patient care.